U.S. patent application number 12/759275 was filed with the patent office on 2010-09-30 for use of erythropoietin.
This patent application is currently assigned to EPOPLUS GMBH & CO. KG. Invention is credited to Ferdinand Hermann Bahlmann, Hermann Haller.
Application Number | 20100247450 12/759275 |
Document ID | / |
Family ID | 30128436 |
Filed Date | 2010-09-30 |
United States Patent
Application |
20100247450 |
Kind Code |
A1 |
Bahlmann; Ferdinand Hermann ;
et al. |
September 30, 2010 |
USE OF ERYTHROPOIETIN
Abstract
The present invention relates to the use of erythropoietin for
stimulating the physiological mobilization, proliferation and
differentiation of endothelial progenitor cells, for stimulating
vasculogenesis, for the therapy of diseases associated with a
dysfunction of endothelial progenitor cells and for producing
pharmaceutical compositions for the treatment of such diseases, and
pharmaceutical compositions which comprise erythropoietin and other
suitable active ingredients for stimulating endothelial progenitor
cells.
Inventors: |
Bahlmann; Ferdinand Hermann;
(Hannover, DE) ; Haller; Hermann; (Hannover,
DE) |
Correspondence
Address: |
OSTROLENK FABER GERB & SOFFEN
1180 AVENUE OF THE AMERICAS
NEW YORK
NY
100368403
US
|
Assignee: |
EPOPLUS GMBH & CO. KG
Hannover
DE
|
Family ID: |
30128436 |
Appl. No.: |
12/759275 |
Filed: |
April 13, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10522426 |
Mar 25, 2005 |
7745387 |
|
|
PCT/EP2003/008229 |
Jul 25, 2003 |
|
|
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12759275 |
|
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|
Current U.S.
Class: |
424/46 ;
514/6.9 |
Current CPC
Class: |
A61P 9/08 20180101; A61P
3/00 20180101; A61K 38/1866 20130101; A61P 9/00 20180101; A61P
29/00 20180101; A61P 3/06 20180101; A61P 17/00 20180101; A61P 9/12
20180101; A61P 43/00 20180101; A61P 13/12 20180101; A61K 38/1816
20130101; A61K 38/1891 20130101; A61P 9/14 20180101; A61P 9/04
20180101; A61P 35/00 20180101; A61P 15/00 20180101; A61P 17/02
20180101; A61K 38/193 20130101; A61P 3/10 20180101; A61P 9/10
20180101; A61P 11/00 20180101; A61K 38/1816 20130101; A61K 2300/00
20130101; A61K 38/1866 20130101; A61K 2300/00 20130101; A61K
38/1891 20130101; A61K 2300/00 20130101; A61K 38/193 20130101; A61K
2300/00 20130101 |
Class at
Publication: |
424/46 ;
514/6.9 |
International
Class: |
A61K 38/28 20060101
A61K038/28; A61K 9/14 20060101 A61K009/14; A61P 3/10 20060101
A61P003/10; A61P 13/12 20060101 A61P013/12; A61P 17/02 20060101
A61P017/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 26, 2002 |
DE |
102 34 192.3 |
Claims
1. A method for therapeutic treatment of diabetes mellitus, said
method comprising administering a pharmaceutical composition
comprising a subpolycythemic erythropoietin dose corresponding to a
weekly dose of 1 to 90 international units (IU) EPO/kg body weight
to a subject in need of said therapeutic treatment for healing said
diabetes mellitus.
2. The method of claim 1, wherein the pharmaceutical composition is
administered parenterally.
3. The method of claim 2, wherein said parenteral administration is
carried out using a mode selected from the group consisting of
intravenous, intramuscular, intracutaneous and subcutaneous,
administration.
4. The method of claim 2, where the pharmaceutical composition is
in a form selected from the group consisting of an injectable form
and an infusible form.
5. The method of claim 1, where the pharmaceutical composition is
administered via pulmonary administration.
6. The method of claim 5, where the pharmaceutical composition is
in a form selected from the group consisting of an aqueous
solution, a nonaqueous solution and a powder.
7. The method of claim 5, where the pharmaceutical composition is
in an aerosol form.
8. The method of claim 1, wherein the pharmaceutical composition is
orally administered.
9. The method of claim 8, where the pharmaceutical composition is
in a form selected from the group consisting of a solution, a
suspension, an emulsion and a tablet.
10. The method of claim 1, where the pharmaceutical composition
comprises at least one further active ingredient which stimulates
endothelial progenitor cells.
11. The method of claim 10, where the further active ingredient is
selected from the group consisting of VEGF, PIGF, GM-CSF, an
HMG-CoA reductase inhibitor and an NO donor.
12. The method of claim 11, wherein the further active ingredient
is the HMG-CoA reductase inhibitor and wherein said inhibitor is a
statin.
13. The method of claim 1, wherein the erythropoietin is human or
animal erythropoietin.
14. The method of claim 1, wherein the erythropoietin is selected
from the group consisting of a derivative, an analog, a
modification and a mutein of erythropoietin.
15. The method of claim 1, wherein said erythropoietin is isolated
from a source selected from the group consisting of human urine,
urine or plasma of patients suffering from aplastic anemia, tissue
cultures of human renal cancer cells, human lymphoblast cells
having the ability to produce human erythropoietin and a hybridoma
culture obtained by cell fusion of a human cell line.
16. The method of claim 1, wherein the erythropoietin is produced
by DNA recombination techniques.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 10/522,426, filed Mar. 25, 2005, which is a 35
U.S.C. .sctn..sctn.371 national phase conversion of
PCT/EP2003/008229, filed Jul. 25, 2003, which claims the priority
of German Patent Application No. 102 34 192.3, filed Jul. 26, 2002,
the entire contents of which are hereby incorporated by reference.
The PCT International Application was published in the German
language.
DESCRIPTION
[0002] The present invention relates to the use of erythropoietin
for stimulating the physiological mobilization, proliferation and
differentiation of endothelial progenitor cells, for stimulating
vasculogenesis, for the therapy of diseases associated with a
dysfunction of endothelial progenitor cells and for producing
pharmaceutical compositions for the treatment of such diseases, and
pharmaceutical compositions which comprise erythropoietin and other
suitable active ingredients for stimulating endothelial progenitor
cells.
[0003] The vascular endothelium is a layer of cells which lines
blood vessels. The endothelium separates the blood from other
vessel layers, and the endothelium does not just represent a
passive barrier but is actively involved in regulating vessel tone.
Reference is also accordingly made to endothelium-dependent
vasodilatation. As a result of its position, the endothelium is
permanently exposed to hemodynamic stress and metabolic stress.
Pathogenic conditions, for example elevated blood pressure,
elevated LDL levels, impaired kidney function or elevated blood
glucose, are therefore frequently associated with functional
endothelial defects which may then be followed by morphologically
detectable lesions such as the formation of atherosclerotic
plaques. A very early sign of an altered or diminished endothelial
function, or endothelial dysfunction, is a reduction in the
endothelium-dependent vasodilatation.
[0004] In coronary heart disease (CHD), but also when risk factors
are present without CHD, for example hypertension,
hyperlipoproteinemia or diabetes, the defects in endothelial
function are manifested by a reduced production of NO (=EDRF) and
increased endothelin production. High plasma levels of endothelin
lead to abnormal adhesion of cells, inflammations, vascular
proliferation and severe vessel constrictions. Disturbances of
endothelial function are additionally characterized by increased
production of adhesion molecules such as ICAM-1 and VCAM-1, causing
platelets and monocytes to adhere to an increased extent to
endothelium. The result of this is an increase in vessel tone.
Thus, an imbalance develops in various systems, favoring
vasoconstriction, adhesion, aggregation, coagulation,
atherosclerosis and atherothrombosis. Even mental stress leads to a
measurable endothelial dysfunction which may persist for up to 4
hours.
[0005] Endothelial cells are involved in the formation of new blood
vessels. The formation of blood vessels is important in a large
number of processes such as, for example, embryogenesis, the female
reproductive cycle, wound healing, tumor growth and the
neovascularization of ischemic areas. Originally, postnatal
formation of blood vessels, that is the formation of blood vessels
after birth, was mainly attributed to angiogenic processes.
Angiogenesis means the formation of new blood vessels through
capillaries sprouting from a pre-existing vascular system. During
angiogenesis, firstly the basement membrane surrounding the blood
vessels is broken down by proteolytic enzymes, and the
extracellular matrix in the perivascular space is fragmented. The
angiogenic stimuli released thereby caused differentiated
endothelial cells which are already present to migrate in the
direction of the chemotactic stimulus, during which they
simultaneously proliferate and are transformed. Juxtapositioning of
endothelial cells then forms new vessel loops with a capillary-type
lumen. The onset of synthesis of a new basement membrane
follows.
[0006] However, recent investigations show that the formation of
new blood vessels in the adult organism derives not only from
angiogenesis but also from vasculogenic mechanisms. Vasculogenesis
means formation of new vessels from endothelial progenitor cells
which are differentiating in situ. The belief that vasculogenesis
is confined to embryo-genesis was refuted by the detection of
endothelial progenitor cells (EPC) in peripheral blood of healthy
humans and animals. It was possible to prove by using animal models
that the endothelial progenitor cells derived from bone marrow are
actively involved in neovascularization. It was also shown that a
specific CD34-positive subgroup of leukocyte which expresses
endothelium-specific antigens becomes established in ischemic
regions. In addition, endothelial progenitor cells (EPC) which make
a significant contribution to the formation of blood vessels in the
adult organism can be obtained from CD133.sup.+ and CD34.sup.+
cells in vitro (Asahara et al., Science, 275 (1997), 964-967;
Crosby et al., Circ. Res., 87 (2000), 728-730; Gehling et al.,
Blood, 95 (2000), 3106-3112). It was additionally shown that
injection of isolated CD34.sup.+ cells or cultivated endothelial
progenitor cells expedites restoration of blood flow in diabetic
mice (Schatteman et al., J. Clin. Invest., 106 (2000), 571-578) and
improves neovascularization in vivo (Asahara et al., Circ. Res., 85
(1999), 221-228; Crosby et al., Circ. Res., 87 (2000), 728-730;
Murohara et al., J. Clin. Invest., 105 (2000), 1527-1536). It was
moreover possible to show that a neovascularization induced by
CD34.sup.+ cells improves cardiac function (Kocher et al., Nat.
Med., 7 (2001), 430-436).
[0007] However, the mechanisms underlying the mobilization and
differentiation of endothelial progenitor cells are not yet fully
explained. Molecular biological and cytobiological investigations
indicate that various cytokines and angiogenic growth factors have
stimulating effects on the mobilization of endothelial progenitor
cells in bone marrow. Thus, it is known that proangiogenic factors
such as VEGF and GM-CSF are able to increase the number of
endothelial progenitor cells (Asahara et al., EMBO, J., 18 (1999),
3964-3972; Takahashi et al., Nat. Med., 5 (1999), 434-438). VEGF
(vascular endothelial growth factor) is a protein which occurs in
various isoforms and which binds to the two tyrosine kinase
receptors VEGF-R1 (flt-1) and VEGF-R2 (flk-1) which occur for
example on the surface of growing endothelial cells (Wernert et
al., Angew. Chemie, 21 (1999), 3432-3435). Activation of VEGF
receptors leads via the Ras-Raf-MAP kinase pathway to expression of
proteinases and specific integrins on the surface of endothelial
cells or endothelial progenitor cells and finally to initiation of
proliferation and migration of these cells in the direction of the
angiogenic stimulus. GM-CSF (granulocyte-macrophage
colony-stimulating factor) is a cytokine which was previously known
in particular for stimulating white blood corpuscles including
neutrophils, macrophages and eosinophils. PIGF (placental growth
factor) is known to stimulate the mobilization of endothelial
progenitor cells but not proliferation thereof. Investigations by
Llevadot et al. (J. Clin. Invest., 108 (2001), 399-405) reveal that
HMG-CoA reductase inhibitors, especially statins, which are
employed as lipid-lowering medicaments and reduce the morbidity and
mortality of coronary disease, are able to mobilize endothelial
progenitor cells. Dimmeler et al. (J. Clin. Invest., 108 (2001),
391-397) were able to show further that statins such as
atorvastatin and simvastatin significantly improve the
differentiation of endothelial progenitor cells in mononuclear
cells and CD34.sup.+ stem cells isolated from peripheral blood in
vitro and in vivo. Thus, treatment of mice with statins led to an
increased number of differentiated endothelial progenitor cells,
with statins showing an effect as strong as that of VEGF.
[0008] Stimulation of the mobilization and/or differentiation of
endothelial progenitor cells represents an important novel
therapeutic strategy for increasing postnatal neo-vascularization,
especially vasculogenesis, and for treating diseases associated
with a dysfunction of endothelial progenitor cells and/or
endothelial cells.
[0009] The present invention is based on the technical problem of
providing means and methods for improved stimulation of endothelial
progenitor cells and for the therapy of disorders particularly
associated with a dysfunction of endothelial progenitor cells.
[0010] The present invention solves this technical problem by
disclosing the use of erythropoietin and/or its derivatives for
stimulating the physiological mobilization of endothelial
progenitor cells, the proliferation of endothelial progenitor
cells, the differentiation of endothelial progenitor cells to
endothelial cells and/or the migration of endothelial progenitor
cells in the direction of an angiogenic or vasculogenic stimulus in
a human or animal body. The present invention also solves this
technical problem by disclosing the use of erythropoietin and/or
its derivatives for the therapy of diseases or pathological states
associated with a dysfunction of endothelial progenitor cells
and/or endothelial cells.
[0011] It has surprisingly been found according to the invention
that a treatment with erythropoietin leads to physiological
mobilization of endothelial progenitor cells, with an increase in
the number of circulating endothelial progenitor cells and
induction of differentiation thereof, especially in comparatively
low EPO doses. In addition, functional deficits, which occur in
certain pathological conditions, of the endothelial progenitor
cells are compensated. It was possible to show according to the
invention that the number of circulating stem cells in patients
with chronic kidney disease in the terminal stage is just as high
as in healthy subjects, but in these patients they have lost the
ability to differentiate to endothelial cells via endothelial
progenitor cells. Thus, the number of cells capable of adhesion and
showing an endothelial cell phenotype is distinctly reduced in
patients with chronic kidney disease compared with healthy
subjects. It has now been found according to the invention that the
number of circulating stem cells increases significantly by more
than 50% after treatment of these patients with erythropoietin.
There is moreover a drastic increase in particular in the number of
cells which develop an endothelial phenotype. As was demonstrated
by means of a functional cell culture assay, there is three-fold
increase in the impaired adhesion ability of the endothelial
progenitor cells due to erythropoietin treatment in patients with
chronic kidney disease. The adhesion ability of differentiating
endothelial progenitor cells and of endothelial cells is one of the
basic preconditions for the formation of new tissues and/or
vessels. Erythropoietin is able in this way to induce
neovascularization, in particular vasculogenesis, in tissues or
organs in which corresponding vasculogenic or angiogenic stimuli
are released.
[0012] Erythropoietin (called EPO hereinafter) can be used
according to the invention to stimulate the physiological
mobilization of endothelial progenitor cells, the proliferation of
endothelial progenitor cells, the differentiation of endothelial
progenitor cells to endothelial cells and/or for migration of
endothelial progenitor cells in the direction of a vasculogenic or
angiogenic stimulus in a human or animal body, in particular an
adult organism. Erythropoietin can therefore advantageously be
employed according to the invention to stimulate the formation of
new vessels by vasculogenesis in tissues or organs in which
pathological vascular lesions are present. In addition, the
formation of endothelial tissue can also be induced owing to the
stimulation of endothelial progenitor cells by erythropoietin.
Erythropoietin can therefore also be employed according to the
invention for treating diseases of the human or animal body which
are associated with a dysfunction of endothelial progenitor cells
and/or endothelial cells.
[0013] In connection with the present invention, "erythropoietin"
or "EPO" means a substance which controls the growth or the
differentiation and the maturation of stem cells via erythroblasts
to erythrocytes. Erythropoietin is a glycoprotein having 166 amino
acids, three glycosylation sites and a molecular weight of about 34
000 Da. During EPO-induced differentiation of erythrocyte
progenitor cells there is induction of globin synthesis and an
increase in the synthesis of the heme complex and in the number of
ferritin receptors. The cell can take up more iron and synthesize
functional hemoglobin thereby. Hemoglobin binds oxygen in mature
erythrocytes. Thus, erythrocytes and the hemoglobin present in them
play a key role in the body's oxygen supply. These processes are
initiated through the interaction of EPO with an appropriate
receptor on the cell surface of erythrocyte progenitor cells
(Graber and Krantz, Ann. Rev. Med. 29 (1978), 51-56).
[0014] Erythropoietin is produced mainly in the kidney, but also in
smaller proportions in the liver and in the brain. Small amounts of
erythropoietin are also found in the serum and, under physiological
conditions, it is at least partly excreted in the urine. Patients
with renal failure are capable of only inadequate erythropoietin
(called EPO hereinafter) production and accordingly suffer from
anemia. Compensation of erythropoietin deficiency by administering
erythropoietin is known. Further clinical applications of
erythropoietin are in the administration of erythropoietin for
iatrogenic anemia following chemotherapy or radiotherapy of
malignant diseases or viral infections (EP 0 456 153 B1). U.S. Pat.
No. 4,732,889 discloses the use of erythropoietin-containing
compositions for the treatment of anemia associated with rheumatoid
arthritis. WO 88/03808 discloses the treatment of hemochromatosis
by means of EPO-containing compositions.
[0015] The term "erythropoietin" used herein includes EPO of every
origin, especially human or animal EPO. The term used herein
encompasses not only the naturally occurring, that is wild-type
forms of EPO, but also its derivatives, analogs, modifications,
muteins, mutants or others, as long as they show the biological
effects of wild-type erythropoietin.
[0016] In connection with the present invention, "derivatives" mean
functional equivalents or derivatives of erythropoietin which are
obtained, with retention of the basic erythropoietin structure, by
substitution of one or more atoms or molecular groups or radicals,
in particular by substitution of sugar chains such as ethylene
glycol, and/or whose amino acid sequences differ from that of the
naturally occurring human or animal erythropoietin protein in at
least one position but essentially have a high degree of homology
at the amino acid level and comparable biological activity.
Erythropoietin derivatives as can be employed for example in the
present invention are disclosed inter alia in WO 94/25055, EP 0 148
605 B1 or WO 95/05465.
[0017] "Homology" means in particular a sequence identity of at
least 80%, preferably at least 85% and particularly preferably at
least more than 90%, 95%, 97% and 99%. The term "homology" which is
known to the skilled worker thus refers to the degree of
relationship between two or more polypeptide molecules, which is
determined by the agreement between the sequences. It is possible
in this connection for an agreement to mean both an identical
agreement and a conservative amino acid exchange.
[0018] The term "derivative" also includes according to the
invention fusion proteins in which functional domains of another
protein are present on the N-terminal part or on the C-terminal
part. In one embodiment of the invention, this other protein may be
for example GM-CSF, VEGF, PIGF, a statin or another factor which
has a stimulating effect on endothelial progenitor cells. In a
further embodiment of the invention, the other protein may also be
a factor which has a stimulating effect on differentiated
endothelial cells, for example angiogenin or bFGF (basic fibroblast
growth factor). It is known that the growth factor bFGF exerts a
strong mitogenic and chemotactic activity on endothelial cells.
[0019] The differences between an erythropoietin derivative and
native erythropoietin may arise for example through mutations such
as, for example, deletions, substitutions, insertions, additions,
base exchanges and/or recombinations of the nucleotide sequences
encoding the erythropoietin amino acid sequences. Obvious
possibilities in this connection are also naturally occurring
sequence variations, for example sequences from another organism or
sequences which have been mutated in a natural way, or mutations
introduced deliberately into the erythropoietin-encoding nucleic
acid sequences with the aid of conventional means known in the art,
for example chemical agents and/or physical agents. In connection
with the invention, therefore, the term "derivative" also includes
mutation erythropoietin molecules, that is erythropoietin
muteins.
[0020] It is also possible according to the invention to employ
peptide or protein analogs of erythropoietin. In connection with
the present invention, the term "analogs" includes compounds which
do not have an amino acid sequence identical to the erythropoietin
amino acid sequence but whose three-dimensional structure greatly
resembles that of erythropoietin and which therefore have a
comparable biological activity. Erythropoietin analogs may be, for
example, compounds which comprise in a suitable conformation the
amino acid residues responsible for the binding of erythropoietin
to its receptors and which are therefore able to simulate the
essential surface properties of the erythropoietin binding region.
Compounds of this type are described for example in Wrighton et
al., Science, 273 (1996), 458.
[0021] The EPO employed according to the invention can be produced
in various ways, for example by isolation from human urine or from
the urine or plasma (including serum) of patients suffering from
aplastic anemia (Miyake et al., J.B.C. 252 (1977), 5558). Human EPO
can be obtained for example also from tissue cultures of human
renal cancer cells (JA-OS 55790/1979), from human lymphoblast cells
which have the ability to produce human EPO (JA-OS 40411/1982) and
from a hybridoma culture obtained by cell fusion of a human cell
lines. EPO can also be produced by genetic engineering methods by
using suitable DNA or RNA which codes for the appropriate amino
acid sequence of EPO to produce the desired protein recombinantly,
for example in a bacterium, a yeast, a plant cell line or animal
cell line. Methods of these types are described for example in EP 0
148 605 B2 or EP 0 205 564 B2 and EP 0 411 678 B1.
[0022] The present invention relates in particular to the use of
erythropoietin (called EPO hereinafter) and/or derivatives thereof
to stimulate the physiological mobilization of endothelial
progenitor cells, the proliferation of endothelial progenitor
cells, the differentiation of endothelial progenitor cells to
endothelial cells and/or for the migration of endothelial
progenitor cells in the direction of a vasculogenic or angiogenic
stimulus in a human or animal body, in particular an adult
organism.
[0023] In connection with the present invention, "endothelial
progenitor cells" (EPC) mean cells which circulate in the
bloodstream and have the ability to differentiate to endothelial
cells. The endothelial progenitor cells which occur during
embryonic development are angioblasts. The endothelial progenitor
cells occurring in the adult organism are angioblast-like cells
which can be obtained from mononuclear cells, in particular
CD34.sup.-CD14.sup.+ monocytes, and/or CD34.sup.+ stem cells, which
have been isolated from peripheral blood.
[0024] In connection with the present invention, "mobilization" or
"physiological mobilization" means the process of activating stem
cells and/or progenitor cells from the bone marrow by growth
factors, with entry of the stem cells or progenitor cells into the
bloodstream, in particular into the peripheral blood.
[0025] In connection with the present invention "proliferation"
means the ability of cells to enlarge and subsequently divide into
two or more daughter cells. The EPO-mediated stimulation of
endothelial progenitor cells thus relates in particular to the
number and thus the dividing behavior of endothelial progenitor
cells.
[0026] In connection with the present invention, "Differentiation"
of endothelial progenitor cells means the development of
mononuclear cells derived from the bone marrow via endothelial
progenitor cells into endothelial cells. "Endothelial cells" mean
the cells which form the endothelium, that is the monolayer
cellular lining of vessels and serous cavities. Endothelial cells
are characterized in that they release vasoactive substances, for
example vasodilating substances such as EDRF (endothelial derived
relaxing factor) or constricting substances such as endothelin,
factors for inhibition or activation of blood clotting and factors
for regulating vascular permeability. Endothelial cells also
synthesize components of the subendothelial connective tissue,
especially collagens of type IV and V, cell adhesion proteins such
as laminin, fibronectin and thrombospondin, growth factors, for
example for smooth muscle cells, and factors for the formation of
new vessels.
[0027] In connection with the present invention, "migration" of
endothelial progenitor cells means that the endothelial progenitor
cells present in the bloodstream migrate in the direction of a
vasculogenic or angiogenic stimulus and become concentrated in the
region of the vasculogenic or angiogenic stimulus. A "vasculogenic
stimulus" means a chemical stimulus in a tissue or blood vessel of
a human or animal body which acts specifically on endothelial
progenitor cells and brings about migration thereof to the site in
the body from which the chemical stimulus originates. The
vasculogenic stimulus induces in this way the vasculogenesis
process. An "angiogenic stimulus" means a chemical stimulus in a
tissue or blood vessel of a human or animal body which acts
specifically on differentiated endothelial cells and brings about
migration thereof to the site in the body from which the chemical
stimulus originates. The angiogenic stimulus brings about in this
way an induction of angiogenesis.
[0028] A further embodiment of the invention provides the use of
erythropoietin and/or derivatives thereof for increasing the
adhesion ability of differentiating endothelial progenitor cells.
Erythropoietin is used according to the invention in particular for
improving the adhesion ability of endothelial progenitor cells,
that is for cell-cell adhesion. The adhesion of differentiating
endothelial progenitor cells or differentiated endothelial cells is
one of the basic preconditions for the formation of new vessels or
of new endothelial tissue. Cell adhesion is mediated by protein
molecules.
[0029] The present invention also relates to the use of
erythropoietin for stimulating the formation of new vessels, in
particular stimulation of vasculogenesis. In connection with the
present invention, "vasculogenesis" means the formation of new
vessels from endothelial progenitor cells which are differentiating
in situ. Thus, according to the invention, the use of
erythropoietin results in increased involvement of endothelial
progenitor cells in the formation of new vessels or in a local
formation of new vessels to restore damaged vascular regions. The
invention thus provides for the use of erythropoietin and/or its
derivatives to promote the formation of new blood vessels and/or
the replacement of damaged vascular regions through local formation
of new blood vessels.
[0030] A further embodiment of the invention provides for the use
of erythropoietin and/or derivatives thereof for stimulating
endothelial progenitor cells to form endothelial tissue.
[0031] A particularly preferred embodiment of the invention
provides the use of erythropoietin and/or derivatives thereof for
the therapy of pathological states or diseases of the human or
animal body which are associated with a dysfunction of endothelial
progenitor cells, or of sequelae thereof.
[0032] In connection with the present invention, "diseases",
"pathological states" or "disorders" mean disturbances of vital
processes in organs or in the whole body resulting in subjectively
experienced or objectively detectable physical, mental or
intellectual changes. The invention is concerned in particular with
diseases associated with a dysfunction of endothelial progenitor
cells, that is diseases which either are the result of such a
dysfunction of these cells or are mediated by these cells.
"Sequelae" mean secondary diseases, that is a second disorder added
to a primary pathological state.
[0033] In connection with the present invention, a "dysfunction" of
endothelial progenitor cells means a disturbance of essential cell
functions such as metabolic activities, response to stimuli,
motility, dividing behavior or differentiation behavior of these
cells. A dysfunction of endothelial progenitor cells may consist
for example of only inadequate or no proliferation of these cells.
Since the proliferation of endothelial progenitor cells is
stimulated by the use of erythropoietin, it is thus possible to
compensate the deficient dividing behavior both of endothelial
progenitor cells and of previously differentiated endothelial
cells, and to increase the number of endothelial progenitor cells
or endothelial cells. A dysfunction of endothelial progenitor cells
may consist for example of the impaired ability of these cells to
differentiate to endothelial cells. The dysfunction of endothelial
progenitor cells may also be caused by their impaired adhesion
ability and/or their impaired ability to migrate in the direction
of an angiogenic or vasculogenic stimulus. Such dysfunctions of
endothelial progenitor cells may lead for example to the impairment
or prevention of the formation of new endothelial tissue and/or
vasculogenesis. A dysfunction of endothelial progenitor cells may
also have a pathogenic cause, for example due to hyper-tension,
hyperlipoproteinemia, uremia or diabetes. The dysfunction of
endothelial progenitor cells may be manifested for example by a
reduced production of NO (=EDRF) by NO synthases (NOS) from
L-arginine, increased endothelin production and/or enhanced
production of adhesion molecules such as ICAM-1 and VCAM-1.
[0034] The diseases associated with a dysfunction of endothelial
progenitor cells are according to the invention in particular
hypercholesterolemia, diabetes mellitus, endothelium-mediated
chronic inflammatory disorders such as inflammations of vessels,
endotheliosis including reticuloendotheliosis, atherosclerosis,
coronary heart disease, myocardial ischemia, angina pectoris,
age-related cardiovascular disorder, ischemic disorders of the
extremities, Raynaud's disease, preeclampsia, pregnancy-induced
hyper-tension, chronic or acute renal failure, especially terminal
renal failure, heart failure, wound healing and sequelae
thereof.
[0035] "Hypercholesterolemia" is characterized by elevated
concentrations of cholesterol in the blood. By far the commonest
form of primary hypercholesterolemia is polygenic
hypercholesterolemia. Secondary hypercholesterolemias frequently
occur in association with diabetes mellitus, nephrotic syndrome,
hypothyroidism and hepatic disorders.
[0036] "Diabetes mellitus" encompasses various forms of glucose
metabolism disorders differing in etiology and symptoms.
Responsible for the development of vessel-related diabetic
complications is, in particular, the AGE-RAGE system. AGEs
(advanced glycation endproducts) are produced by a series of
complex reactions after long-lasting exposure of proteins or lipids
to reducing sugars, for example glucose. The formation of AGEs
takes place during the normal aging process and to an increased
extent in diabetes mellitus and Alzheimer's disease. Binding of
AGEs leads to oxidative stress, activation of the NF-KB
transcription factor and thus a disturbance of endothelial
homeostasis.
[0037] "Endothelium-mediated chronic inflammatory disorders" are
disorders or conditions of a human or animal body which derive from
a defense response of the body and its tissues to harmful stimuli,
with certain signal molecules altering the properties of
endothelial cells so that, in concert with the activation of other
cell types, leukocytes remain adherent to endothelial cells,
finally penetrate into the tissue and there initiate inflammation.
One example of an endothelium-mediated inflammation is leukocytic
vasculitis. A central part is played in the activation of an
endothelium-mediated inflammatory event by the transcription factor
NF-.kappa.B. Another system leading to the development of
endothelial cell-mediated chronic inflammations is the AGE-RAGE
system.
[0038] "Endotheliosis" means degenerative and proliferative
endothelial changes associated with non-thrombopenic purpura.
"Reticuloendotheliosis" means diseases of the reticulohistiocytic
system, such as reticulum, reticulosis, reticulohistiocytosis and
Hand-Schuller-Christian disease.
[0039] "Myocardial ischemia" means bloodlessness or hypoperfusion,
that is an impairment of the blood supply, of the muscular wall of
the heart as a result of inadequate or absent arterial supply of
blood. A "cardiac infarct" or "myocardial infarct" is a necrosis of
a localized region of the myocardium, which usually occurs as an
acute event complicating chronic coronary heart disease. "Coronary
heart disease" or "ischemic heart disease" is a degenerative
coronary disorder which, owing to a constriction or a closure of
coronary vessels of the heart, leads to a reduced blood supply to
the myocardium. "angina pectoris" means an acute coronary
insufficiency or stenocardia which may be induced by an imbalance
of the oxygen supply and oxygen demand associated with coronary
heart disease, coronary spasms, impairments of blood flow, cardiac
arrhythmias, hypertension or hypotension. "Raynaud's disease" means
ischemic states which are caused by vasoconstriction, that is
vessel spasms, and occurs episodically, usually in the arteries of
the fingers. Primary Raynaud's disease is a purely functional
impairment of the small vessels supplying the distal parts of the
extremities, whereas secondary Rynaud's disease has another disease
underlying it, for example an inflammation of vessels.
[0040] "Preeclampsia" is an endothelial and vascular disease of the
maternal body and appears to be the effect of endotheliotropic
substances from the placenta. Preeclampsia is a multisystem
disorder which may lead to disturbances of function of numerous
organs and be manifested by diverse symptoms. The impairments of
blood supply which are typical of the disorder are the result of an
increased vascular resistance, possibly with local variations in
severity. It is regarded as confirmed that an endothelial
dysfunction is the central component of the pathogenesis of
preeclampsia.
[0041] "Renal failure" means in connection with the present
invention the restricted ability of the kidneys to excrete
substances normally excreted in the urine, and in advanced stages
there is also loss of the ability to regulate the electrolyte,
water and acid-base balance. Terminal renal failure is
characterized by a collapse of the excretory and endocrine function
of the kidneys.
[0042] The renal failure may according to the invention be acute
renal failure which is also referred to as acute kidney failure or
shock aneuria. Acute renal failure is characterized by a sudden
partial or complete loss of the excretory function of the kidneys
as a result of usually reversible kidney damage. The cause may be
hypoperfusion due to hypovolemia, hypotension and dehydration
resulting from blood losses (polytrauma, gastrointestinal or
postpartum bleeding, major surgical procedures on the heart,
vessels, abdomen or prostate), shock (myocardial infarct,
embolism), serious infections (sepsis, peritonitis, cholecystitis),
hemolysis (hemolytic-uremic syndrome, paroxysmal hemoglobulinuria,
transfusion reaction), myolysis (crush syndrome, rhabdomyolysis,
myositis, burns), water and electrolyte losses (massive vomiting,
diarrhea, excessive sweating, ileus, acute pancreatitis). Further
causes may be nephrotoxins such as exogenous toxins, for example
aniline, glycol compounds, methanol and the like, or endogenous
toxins, for example myoglobin and oxalates. Further causes of acute
renal failure are renal diseases, for example inflammatory
nephropathies or rejection reactions following renal
transplantation. Acute renal failure may also be caused by
retention of urine following obstruction to the flow of urine. The
treatment according to the invention of acute renal failure with
erythropoietin leads according to the invention to prevention or at
least diminution of progression of acute renal failure.
[0043] The renal failure may according to the invention also be
chronic renal failure. Causes of chronic renal failure are
vascular, glomerular and tubulointerstitial renal disorders,
infections and inborn or acquired structural defects. Causes of
chronic renal failure are, inter alia, chronic glomerulopathy,
chronic pyelonephritis, analgesic nephropathy, obstructive uropathy
and arterio- and arteriolosclerosis. The terminal stage of chronic
renal failure is uremia. The treatment according to the invention
of chronic renal failure with erythropoietin leads according to the
invention to a diminution in the progression of chronic renal
failure.
[0044] In connection with the present invention, "heart failure"
means a pathological state which is also referred to as myocardial
insufficiency or weakness of the heart muscle. Heart failure is
characterized by inadequate functioning of the heart, the heart no
longer being capable of efficient delivery to comply with the
requirements. Heart failure can be categorized according to various
aspects. For example, according to the affected segment of the
heart it is classified as right heart failure, left heart failure
and failure on both sides (global failure). According to the
stability of an equilibrium influenced by physiological and
therapeutic mechanisms, a distinction is made between compensated
and decompensated heart failure. Classification takes place into
acute and chronic heart failure according to the time course.
Causes of heart failure are, inter alia, myocardial infarction,
cardiomyopathy, inborn or acquired cardiac defects, essential or
pulmonary hypertension, cardiac arrhythmias, coronary heart disease
or myocarditis.
[0045] In connection with the present invention, "wound healing"
means the physiological processes for regenerating damaged tissue
and for closing a wound, especially formation of new connective
tissue and capillaries. The wound healing may be primary wound
healing (first intention healing), which is characterized by rapid
and complication-free closure and substantially complete recovery
as a result of minimal formation of new connective tissue between
the edges of a wound, which have a good blood supply and are
approximated where appropriate, of a clean wound. Wounds where the
edges of the wound are further apart and, in particular, crushed or
necrotic, and infected wounds, undergo delayed secondary wound
healing (second intention healing) in which, as a result of an (a)
bacterial inflammation, there is filling of the tissue defect with
granulation tissue and extensive formation of scar tissue.
Epithelialization starting from the edge terminates the wound
healing. The wound healing is divided into three phases, namely
latency phase, proliferative phase and repair phase. The latency
phase in turn is divided into the exudative phase with scab
formation, especially in the first few hours after the wound
occurred, and the absorptive phase with catabolic autolysis, which
extends over a period of from one to three days after the wound
occurred. The proliferative phase is characterized by anabolic
repair with production of collagen by fibroblasts and occurs on the
fourth to seventh day after the wound occurred. The repair phase
occurs after the eighth day after the wound occurred and is
characterized by transformation of the granulation tissue into a
scar.
[0046] A "wound" means in connection with the present invention an
interruption of the coherence of body tissues with or without loss
of substance and caused by mechanical injury or physically caused
cell damage. Types of wound are mechanical wounds, thermal wounds,
chemical wounds, radiation wounds and disease-related wounds.
Mechanical wounds arise through traumatic violence and occur in
particular as incision and puncture wounds, crushing, lacerating,
tearing and abrading wounds, scratch and bite wounds and projective
wounds. Thermal wounds arise through exposure to heat or cold.
Chemical wounds arise in particular through the action of acids or
alkalis. Radiation wounds arise for example through exposure to
actinic and ionizing radiation. Wounds occurring in relation to
disease are in particular congestion-related wounds, traumatic
wounds, diabetic wounds etc. The invention provides in particular
for erythropoietin to be administered preferably topically or
intravenously for wound healing.
[0047] The present invention therefore relates to the use of
erythropoietin for the therapy of hypercholesterolemia, diabetes
mellitus, endothelium-mediated chronic inflammatory disorders,
endotheliosis including reticuloendotheliosis, atherosclerosis,
coronary heart disease, myocardial ischemia, angina pectoris,
age-related cardiovascular disorders, ischemic disorders of the
extremities, preeclampsia, Raynaud's disease, pregnancy-induced
hypertension, chronic or acute renal failure, especially terminal
renal failure, heart failure, wound healing and sequelae
thereof.
[0048] The invention provides for erythropoietin to be administered
to a patient in a therapeutically effective dose which is
sufficient to cure the condition of an aforementioned disease, in
particular a disease associated with a dysfunction of endothelial
progenitor cells, or to prevent this condition, to stop the
progression of such a disease and/or to alleviate the symptoms of
such a disease. The dose to be administered to a patient depends on
many factors, for example the age, body weight and gender of the
patient, the severity of the disorders etc.
[0049] It is particularly preferred according to the invention for
erythropoietin, in all the uses, methods and compositions of the
present disclosure, to be used in very small amounts which are
below the amounts known to be employed, administering in particular
in vivo, i.e. per patient, EPO doses of from 200 to 2 000 units
(IU; international units)/week, preferably doses of from 500 to 2
000 IU/week, depending on the severity of the disorder and
depending on renal function. The doses, provided according to the
invention, of from 200 to 2 000 units (IU)/week and per patient,
especially from 500 to 2 000 IU/week and per patient, are
subpolycythemic doses, that is doses which do not lead to
erythrocytosis with hematocrit values of more than 50%. The
subpolycythemic doses provided according to the invention
correspond to weekly doses of about 1 to 90 units (IU) of EPO/kg of
body weight, in particular 1 to 45 IU of EPO/kg of body weight, or
a comparable weekly dose of Aranesp of from 0.005 to 0.45 .mu.g/kg
of body weight, in particular 0.005 to 0.225 .mu.g/kg of body
weight. Aranesp is a doubly PEGylated EPO. The dose of from 200 to
2 000 units/week per patient, in particular from 500 to 2 000
IU/week and per patient, which is provided according to the
invention for the treatment of diseases or pathological states
associated with a dysfunction of endothelial progenitor cells is
very low compared with the initial dose of 50-150 IU/kg of body
weight/week (usually starting with 4 000-8 000 IU/week, but also
considerably higher if the result of therapy is unsatisfactory)
normally employed for the therapy of renal anemia.
[0050] A particularly preferred embodiment of the invention relates
to the use of erythropoietin and/or its derivative as active
ingredient for producing a pharmaceutical composition or a
medicament for the therapy of pathological states or diseases
associated with a dysfunction of endothelial progenitor cells.
[0051] An "active ingredient" means according to the invention an
endogenous or exogenous substance which on contact with target
molecules or target cells or target tissues influences in a
differentiated manner specific functions of tissues, organs or
organisms. The invention thus provides for erythropoietin as active
ingredient of the pharmaceutical composition of the invention
influencing the proliferation, differentiation and/or migration
behavior of endothelial progenitor cells on contact therewith in a
human or animal organism in such a way that dysfunctions of
endothelial progenitor cells can be compensated and the diseases
occurring as a consequence of these dysfunctions effectively
controlled, alleviated or eliminated, or these diseases effectively
prevented.
[0052] In connection with the present invention, a "pharmaceutical
composition" or a "medicament" means a mixture which is used for
diagnostic, therapeutic and/or prophylactic purposes, that is
promoting or restoring the health of a human or animal body, and
which includes at least one natural or synthetically produced
active ingredient which brings about the therapeutic effect. The
pharmaceutical composition may be either a solid or a liquid
mixture. For example, a pharmaceutical composition including the
active ingredient may comprise one or more pharmaceutically
acceptable components. The pharmaceutical composition may
additionally include additives normally used in the art, for
example stabilizers, manufacturing materials, release agents,
disintegrants, emulsifiers or other substances normally used for
pharmaceutical composition production.
[0053] The invention provides in particular the use of
erythropoietin and/or a derivative thereof as active ingredient for
producing a medicament for the therapy of hypercholesterolemia,
diabetes mellitus, endothelium-mediated chronic inflammatory
disorders such as inflammations of vessels, endotheliosis including
reticuloendotheliosis, atherosclerosis, coronary heart disease,
myocardial ischemia, angina pectoris, age-related cardiovascular
disorder, ischemic disorders of the extremities, Raynaud's disease,
preeclampsia, pregnancy-induced hypertension, acute or chronic
renal failure, especially terminal renal failure, heart failure,
wound healing and sequelae thereof.
[0054] The pharmaceutical composition of the invention may be
suitable both for topical and for systemic administration.
[0055] A preferred embodiment of the invention provides for the
pharmaceutical composition to be used for parenteral, in particular
intravenous, intramuscular, intracutaneous or subcutaneous
administration. The erythropoietin-containing medicament preferably
has the form of an injection or infusion.
[0056] A further use provides for the erythropoietin-containing
pharmaceutical composition to be administered orally. For example,
the erythropoietin-containing medicament is administered in a
liquid dosage form such as a solution, suspension or emulsion, or a
solid dosage form such as a tablet.
[0057] A further use provides for the pharmaceutical composition to
be suitable for pulmonary administration or for inhalation. The
invention thus provides for erythropoietin to be administered in a
therapeutically effective manner directly onto the lungs of the
patient. This type of administration of erythropoietin makes it
possible to deliver an erythropoietin dose quickly to a patient
without the need to perform an injection. When erythropoietin is
absorbed through the lungs it is possible to deliver considerable
amounts of erythropoietin via the lungs to the bloodstream, which
leads to increased amounts of erythropoietin in the bloodstream. In
a preferred embodiment of the invention, the pharmaceutical
composition to be absorbed through the lung is an aqueous or
nonaqueous solution or a dry powder. When the
erythropoietin-containing medicament to be administered by the
pulmonary route is in the form of a dry powder, the latter
preferably includes erythropoietin-containing particles, where the
particles have a diameter of less than 10 .mu.m, so that the
medicament can also reach distal regions of the patient's lung. A
particularly preferred embodiment of the invention provides for the
medicament which is to be administered by the pulmonary route to be
in the form of an aerosol.
[0058] A particularly preferred embodiment of the invention relates
to the use of erythropoietin for producing a pharmaceutical
composition for the therapy of diseases associated with a
dysfunction of endothelial progenitor cells, where the
pharmaceutical composition comprises besides erythropoietin as
active ingredient at least one further additional active ingredient
to stimulate endothelial progenitor cells.
[0059] The further active ingredient is preferably an active
ingredient which stimulates in particular the physiological
mobilization of endothelial progenitor cells from the bone marrow.
However, the further active ingredient may also be according to the
invention an active ingredient which stimulates in particular the
dividing behavior, that is the proliferation, of endothelial
progenitor cells. However, there is also the possibility according
to the invention for the further active ingredient in particular to
stimulate the differentiation behavior and/or the migration
behavior of endothelial progenitor cells. The further active
ingredient which stimulates endothelial progenitor cells is
particularly preferably VEGF, PIGF, GM-CSF, an HMG-CoA reductase
inhibitor, in particular a statin such as simvastatin, mevastatin
or atorvastatin, and/or an NO donor, especially L-arginine.
[0060] The invention also provides for the at least one further
active ingredient in particular to stimulate differentiated
endothelial cells, that is the proliferation and/or migration
thereof, but not endothelial progenitor cells. Particular
preference is given in this connection to bFGF (basic fibroblast
growth factor) or angiogenin.
[0061] A further embodiment of the invention relates to the use of
erythropoietin and/or derivatives thereof as active ingredient for
producing a pharmaceutical composition to stimulate endothelial
progenitor cells, in particular to stimulate the mobilization,
proliferation, differentiation to endothelial cells and/or for
migration in the direction of a vasculogenic or angiogenic
stimulus. The invention further provides for the use of
erythropoietin and/or its derivatives as active ingredient for
producing a pharmaceutical composition to stimulate vasculogenesis
and/or endothelium formation, in particular in the adult human or
animal organism.
[0062] The present invention therefore also relates to
pharmaceutical compositions to stimulate endothelial progenitor
cells, in particular to stimulate the mobilization, proliferation,
differentiation thereof to endothelial cells and/or migration in
the direction of a vasculogenic or angiogenic stimulus, to
stimulate vasculogenesis and/or endothelium formation and for the
treatment of disease of the human or animal body which are
associated with a dysfunction of endothelial progenitor cells
and/or endothelial cells. The present invention relates in
particular to pharmaceutical compositions or medicaments which
include erythropoietin as active ingredient and at least one
further active ingredient to stimulate endothelial progenitor cells
and/or differentiated endothelial cells. In a preferred embodiment,
the present invention relates to pharmaceutical compositions which
include erythropoietin and at least one further active ingredient
from the group consisting of VEGF, PIGF, GM-CSF, an HMG-CoA
reductase inhibitor, in particular a statin such as simvastatin,
mevastatin or atorvastatin, an NO donor, especially L-arginine,
bFGF and angiogenin.
[0063] A further preferred embodiment of the invention relates to
the use of erythropoietin for producing a transplantable
endothelial cell preparation. The invention provides in this
connection in particular for endothelial cells to be produced in
vitro by cultivating endothelial progenitor cells in the presence
of erythropoietin and subsequently transplanted into a recipient
organism, in particular an organism suffering from a disease
associated with a dysfunction of endothelial progenitor cells. For
example, mononuclear cells (MNC) can be isolated from blood by
density gradient centrifugation and cultivated in suitable culture
media in vitro. Methods for the isolation and in vitro cultivation
of mononuclear cells are described for example in Asahara, Science,
275 (1997), 964-967; Dimmeler et al., J. Clin. Invest., 108 (2001),
391-397 and Llevadot et al., J. Clin. Invest., 108 (2001) 399-405.
The mononuclear cells are then cultivated further in the presence
of erythropoietin in order to stimulate the proliferation and
differentiation behavior of the endothelial progenitor cells
present in the MNCs, and in particular to increase the number of
differentiated adherent endothelial cells. The invention also
provides for the cultivation of the MNCs to take place in the
presence of erythropoietin and at least one further substance which
stimulates the proliferation and differentiation of endothelial
progenitor cells. The further substance particularly preferably
employed is VEGF, PIGF, GM-CSF, an NO donor such as L-arginine or
an HMG-CoA reductase inhibitor such as a statin, in particular
simvastatin, mevastatin or atorvastatin.
[0064] A further preferred embodiment of the invention provides for
the use of erythropoietin for the pretreatment and/or further
treatment of tissues or organs to be transplanted. In this case,
the transplants are treated with erythropoietin before the
transplantation, preferably immediately before, while still in the
donor organism. The recipient organism can likewise be treated with
erythropoietin from the time of transplantation onwards. This
treatment of the organs or tissues to be transplanted, both
directly before and after transplantation, with erythropoietin
achieves according to the invention rapid formation of new blood
vessels in the transplant after transplantation has taken place
into a body, because of the induced vasculogenesis, and rapid
connection of these newly formed blood vessels to the blood system
of the recipient organism. The formation of endothelia is likewise
achieved quickly in this way. The treatment of organ or tissue
transplants with erythropoietin thus brings about faster
incorporation of these systems in the body, thus considerably
reducing the risk of rejection.
[0065] A further development of the invention provides for the
organ or tissue transplants to be treated before transplantation
with erythropoietin in combination with at least one further factor
which stimulates endothelial progenitor cells. This factor is
preferably a substance from the group consisting of VEGF, PIGF,
GM-CSF, an HMG-CoA reductase inhibitor, for example a statin, in
particular simvastatin, mevastatin or atorvastatin, or an NO donor,
in particular L-arginine. A further development provides for the
organ or tissue transplants to be treated before transplantation
besides erythropoietin with a further substance which stimulates
the proliferation and migration of differentiated endothelial
cells. This substance is particularly preferably angiogenin or
bFGF. A further development provides for the pretreatment of the
organ or tissue transplants with erythropoietin to take place using
isolated and, where appropriate, in vitro expanded endothelial
progenitor cells.
[0066] A further particularly preferred embodiment of the invention
provides for erythropoietin to be used to produce implantable or
transplantable cell-containing in vitro organs or tissues. The
invention provides in particular for the organ or tissue produced
in vitro to be treated before the transplantation or implantation
with erythropoietin in vitro in order to stimulate endothelial
progenitor cells which are present in the body of the recipient
organism, especially the physiological mobilization, migration,
proliferation and differentiation thereof. The recipient organism
is preferably treated further, after transplantation or
implantation of the in vitro organ or tissue, with erythropoietin
in the doses of the invention. Treatment of the in vitro organ or
tissue before transplantation or implantation with erythropoietin
and, where appropriate, subsequent treatment of the recipient
organism with erythropoietin achieves according to the invention
rapid formation of new blood vessels in the in vitro organ or
tissue system after transplantation or implantation has taken place
into a body, because of the induced vasculogenesis, and rapid
connection of these newly formed blood vessels to the blood system
of the recipient organism. Rapid formation of endothelia and thus
reendothelialization is likewise achieved in this way. Treatment of
the in vitro organ or tissue systems with erythropoietin thus
brings about faster incorporation of these systems into the body,
thus considerably reducing the risk of rejection, and serves to
protect the transplant.
[0067] An "in vitro organ or tissue system" means a transplantable
or implantable cell-containing tissue or organ which is produced in
vitro using defined cells and/or defined tissues and under defined
culture conditions. An "implantable in vitro organ or tissue
system" means a system which, besides cells, includes exogenous
materials. A "transplant-able in vitro organ or tissue system"
means in particular a cell-containing system which, besides cells,
tissue or organs of the same or a different individual, comprises
endogenous substances. In vitro organs or tissues are characterized
in particular by substantially corresponding in terms of their
structure to the native organs or tissues which are to be replaced,
and thus are able to undertake the function of the replaced native
organs or tissues in vivo.
[0068] One development of the invention provides for the in vitro
organ or tissue systems to be treated before transplantation or
implantation with erythropoietin in combination with at least one
further factor which stimulates endothelial progenitor cells. This
factor is preferably a substance from the group consisting of VEGF,
PIGF, GM-CSF, an HMG-CoA reductase inhibitor, in particular
simvastatin, mevastatin or atorvastatin, and an NO donor. A further
development provides for the in vitro organ or tissue systems to be
treated before transplantation or implantation besides
erythropoietin with a further substance which stimulates the
proliferation and migration of differentiated endothelial cells.
This substance is particularly preferably angiogenin or bFGF. A
further development provides for the in vitro organ or tissue
systems additionally to comprise isolated and, where appropriate,
in vitro expanded endothelial progenitor cells.
[0069] A further preferred embodiment of the invention relates to
the use of erythropoietin for producing vascular prostheses or
heart valves, where the vascular prostheses or heart valves are
coated with erythropoietin before insertion into a body, in
particular a human body. The coating of the vascular prostheses or
heart valves with erythropoietin achieves stimulation of
endothelial progenitor cells in the body of the recipient organism,
stimulating in particular their mobilization from the bone marrow,
their proliferation, their differentiation to endothelial cells and
their migration to the employed vascular prostheses or heart
valves. Following introduction of the vascular prosthesis or heart
valves produced in this way into a body, the latter can be treated
further with erythropoietin, in particular in the doses of the
invention. This results in faster formation of endothelial layers
on the employed vascular prostheses and thus faster incorporation
into the relevant area of the body. A preferred development
provides for additionally employed isolated and, where appropriate,
in vitro expanded endothelial progenitor cells for coating the
vascular prostheses and heart valves.
[0070] The present invention likewise relates to a method for
stimulating endothelial cell formation in vitro comprising
[0071] a) isolation of cell populations comprising endothelial
progenitor cells from blood by means of density gradient
centrifugation
[0072] b) cultivation of the isolated cell populations comprising
endothelial progenitor cells in cell culture medium, and
[0073] c) cultivation of the cell populations in the presence of
erythropoietin.
[0074] The cultivation of the cell populations can according to the
invention take place in the presence of a further substance which
stimulates endothelial progenitor cells.
[0075] The present invention further relates to a method for
treating diseases associated with a dysfunction of endothelial
progenitor cells by administering erythropoietin in a dose of from
200 to 2 000 IU/week, in particular in a dose of from 500 to 2 000
IU/week, to a patient with such a disease. The method of the
invention is particularly suitable for treating diseases of the
human body such as hypercholesterolemia, diabetes mellitus,
endothelium-mediated chronic inflammatory disorders such as
inflammations of vessels, endotheliosis including
reticuloendotheliosis, atherosclerosis, coronary heart disease,
myocardial ischemia, angina pectoris, age-related cardiovascular
disorder, ischemic disorders of the extremities, Raynaud's disease,
preeclampsia, pregnancy-induced hypertension, acute or chronic
renal failure, especially terminal renal failure, heart failure,
wound healing and sequelae.
[0076] A preferred embodiment of the method of the invention for
treating diseases associated with a dysfunction of endothelial
progenitor cells provides for administration to the patient besides
erythropoietin of at least one further active ingredient selected
from the group consisting of VEGF, PIGF, GM-CSF, an HMG-CoA
reductase inhibitor and an NO donor. The HMG-CoA reductase
inhibitor which is administered is preferably a statin such as
simvastatin, mevastatin or atorvastatin. The NO donor which is
administered is preferably L-arginine.
[0077] A further preferred embodiment of the method of the
invention for treating diseases associated with a dysfunction of
endothelial progenitor cells provides for endothelial progenitor
cells to be isolated from the blood of a human organism, to be
expanded in vitro using erythropoietin and to be differentiated to
endothelial cells and, after purification and isolation of the
differentiated endothelial cells or the differentiating endothelial
progenitor cells, the latter then to be transplanted in a targeted
manner into a region of the body, a tissue or an organ of a patient
which is damaged owing to the dysfunction of endothelial progenitor
cells and/or endothelial cells, in order to induce local formation
of new endothelium there. A more targeted and faster treatment of
the damaged regions of the body, tissues and/or organs of the
patient is possible in this way. This embodiment of the method of
the invention for treating diseases associated with a dysfunction
of endothelial progenitor cells comprises the following steps:
[0078] a) isolation of cell populations comprising endothelial
progenitor cells from blood by means of density gradient
centrifugation,
[0079] b) cultivation of the cell populations comprising
endothelial progenitor cells in cell culture medium,
[0080] c) cultivation of the cell populations comprising
endothelial progenitor cells in the presence of erythropoietin to
stimulate the proliferation of endothelial progenitor cells and/or
differentiation thereof to endothelial cells,
[0081] d) isolation and purification of the differentiated
endothelial cells, and
[0082] e) transplantation of the differentiated endothelial cells
into a body with a disease associated with a dysfunction of
endothelial progenitor cells.
[0083] Following transplantation of the differentiated endothelial
cells into a body, the latter can be treated further with
erythropoietin, in particular in the doses of from 200 to 2 000
IU/week provided according to the invention.
[0084] It is possible according to the invention for the cell
populations comprising endothelial progenitor cells to be
cultivated in vitro in the presence of at least one further active
ingredient selected from the group consisting of VEGF, PIGF,
GM-CSF, an HMG-CoA reductase inhibitor and an NO donor. The HMG-CoA
reductase inhibitor used for the cultivation is preferably a statin
such as simvastatin, mevastatin or atorvastatin.
[0085] A further preferred embodiment of the invention relates to a
method for treating vascular disorders, comprising:
[0086] a) isolation of cell populations comprising endothelial
progenitor cells from blood by means of density gradient
centrifugation,
[0087] b) cultivation of the cell populations comprising
endothelial progenitor cells in cell culture medium,
[0088] c) cultivation of the cell populations comprising
endothelial progenitor cells in the presence of erythropoietin to
stimulate the proliferation of endothelial progenitor cells and/or
differentiation thereof to endothelial cells,
[0089] d) isolation and purification of the differentiated
endothelial cells, and
[0090] e) transplantation of the endothelial cells into a body with
a vascular disorder.
[0091] Following transplantation of the endothelial cells into the
body with a vascular disorder, the latter can be treated further
with erythropoietin, preferably in the doses of the invention of
from 200 IU/week to 2 000 IU/week.
[0092] It is possible according to the invention for the cell
populations comprising endothelial progenitor cells to be
cultivated in the presence of at least one further active
ingredient selected from the group consisting of VEGF, PIGF, GM-CSF
and/or an HMG-CoA reductase inhibitor. The HMG-CoA reductase
inhibitor used for the cultivation is preferably a statin such as
simvastatin, mevastatin or atorvastatin.
[0093] The method of the invention for treating vascular disorders
thus provides for endothelial progenitor cells to be isolated from
the blood of a human organism, to be expanded in vitro using
erythropoietin and to be differentiated to endothelial cells and,
after purification and isolation of the differentiated endothelial
cells or the differentiating endothelial progenitor cells, the
latter then to be transplanted in a targeted manner into a damaged
blood vessel or an ischemic region in order to induce local
neovascularization there. More targeted and faster treatment of
damaged blood vessels or ischemic tissues is possible in this way.
The method of the invention for treating vascular disorders is
particularly suitable for treating vascular disorders such as
ischemia, especially cerebral ischemia, ischemic disorders of the
extremities, myocardial ischemia, myocardial infarction, stroke,
coronary heart disease, angina pectoris, acute arterial occlusion,
arterial occlusive disease, Raynaud's disease and ergotism.
[0094] Further advantageous developments of the invention are
evident from the dependent claims.
[0095] The invention is explained in more detail by means of the
following figures and examples.
[0096] FIG. 1 shows the results of a FACS analysis of circulating
CD34.sup.+ stem cells (cSC). (A-D): patients' samples; (E-F):
isotype controls. cSC were identified by means of the additional
expression of the CD34 marker (B and F), by means of the
characteristic low to moderate CD45 antigen expression (C and G)
and by means of the characteristic light scattering properties (D
and H). The absolute cSC number was calculated per 100 000
monocytes and lymphocytes.
[0097] FIG. 2 shows a quantitative determination of circulating
stem cells by means of flow cytometry. The figure shows the
time-dependent effect of erythropoietin treatment using rhEPO
(recombinant human erythropoietin) after 0, 2, 4, 6 and 8 weeks.
n=11, the values correspond to averages+/-standard deviation.
Medians depicted as line.
*: p<0.01 compared with 2 weeks;
.quadrature...quadrature..p<0.05 compared with 4 weeks, #:
p<0.05 compared with 8 weeks.
[0098] FIG. 3 shows a quantitative determination of cultivated
endothelial progenitor cells (EPC). The figure shows that rhEPO
treatment increases the relative number of EPCs. EPCs were isolated
before the treatment of renal patients with rhEPO and 2, 4, 6 and 8
weeks after treatment of the patients with rhEPO, and characterized
by means of their adhesion ability and the two markers acLDL-Dil
and UEA-1 FITC. n=11, the values correspond to averages+/-standard
deviation. Medians depicted as line.
*: p<0.01 compared with the period before treatment; #:
p<0.001 compared with the period before treatment.
[0099] FIG. 4 shows the quantitative determination of cultivated
endothelial progenitor cells (EPC). The figure shows that the
absolute number of EPCs before initiation of rhEPO therapy is
significantly reduced compared with healthy age- and gender-matched
subjects. Patients with renal anemia thus show distinct EPC
dysfunction compared with control subjects. This reduced number of
functional EPC was compensated 8 weeks after starting rhEPO therapy
for renal anemia. EPCs were isolated before the treatment of renal
patients with rhEPO and 2, 4, 6 and 8 weeks after treatment of the
patients with rhEPO, and characterized by means of their adhesion
ability and the two markers acLDL-Dil and UEA-1 FITC. n=11. The
example shown is the course over 8 weeks and all the controls. The
absolute values are shown on the one hand as individual values. In
addition, box plots are shown (90th/75th/50th/25th and 10th
percentiles and the average). Age- and gender-matched subjects for
which EPCs were isolated and characterized analogously (n=11)
served as healthy control.
[0100] FIG. 5 shows the effect of erythropoietin on wound healing.
The figure shows that on treatment of a standardized skin wound on
mice, made with a tissue punch, with erythropoietin the wound was
completely closed only after 7 to 8 days, whereas on treatment of
the wound with physiological sodium chloride solution (saline) the
wound was not completely closed until after 13 to 14 days.
Treatment with erythropoietin or physiological sodium chloride
solution started 7 days before making the skin wound. Recombinant
human erythropoietin was administered once a week by s.c.
(subcutaneous) injection (0.1 .mu.g/kg Aranesp) (n=5 per
group).
[0101] FIG. 6 shows that erythropoietin diminishes the loss of
renal function after acute kidney failure (acute renal failure).
Sprague Dawley rats (250-300 g) were included in the study. The
rats were anesthetized with ketamine (120 mg/kg) and Rompun (10
mg/kg). One of the experimental groups received Aranesp 0.1
.mu.g/kg of body weight once on the day before induction of the
acute kidney failure. The comparison group comprised experimental
animals each given an s.c. injection of sodium chloride at the same
time. Blood flow into the kidney was stopped for 45 minutes by
placing an arterial clamp on the right renal arteries. A left
nephrectomy was performed in this time. A sham operation was
performed on a further control group. This entailed opening the
abdomen, exposing the left renal artery but not stopping the blood
supply, and removing the contralateral right kidney. All the
animals were anesthetized for 60 min and sacrificed 24 h after the
operation. The 45-minute ischemia with subsequent reperfusion of
the remaining right kidney led to an extensive acute loss of renal
function in the animals treated with sodium chloride. This is
reflected by a serum creatinine level 24 h after the
ischemia-reperfusion which is 7 times higher than the level before
the ischemia-reperfusion (p<0.05). By contrast, the animals
treated with erythropoietin analog Aranesp showed only a four-fold
increase in the serum creatinine levels one day after induction of
the ischemia-reperfusion damage. There was no increase in the
retention levels in the animals which underwent left nephrectomy
and a sham operation on the right kidney. The figure shows the
creatinine concentration in the serum of EPO-treated animals
(IR+EPO), NaCl-treated animals (IR) and sham-operated animals (sham
OP) before ischemia-reperfusion (IR) injury and 24 hours
thereafter. It is evident from the figure that the serum creatinine
concentration in the Aranesp-treated animals is almost halved
compared with the control without (NaCl treatment) 24 hours after
ischemia-reperfusion injury.
[0102] FIG. 7 shows the Kaplan-Mayer survival plots of two
experimental groups treated either with Aranesp or NaCl after
induction of chronic renal failure. 8-week old Sprague Dawley rats
were included in the study. The rats were anesthetized with
ketamine (120 mg/kg) and Rompun (10 mg/kg). The right kidney was
removed from them on day 0 and, immediately after removal, was
fixed in formalin for histological examination. The segmental
arteries which supply the upper and lower renal pole of the left
kidney were ligated. This results in a renal infarction of the
corresponding areas of the kidney, and only the middle third of the
kidney retains its function. The rats received s.c. injection of
Aranesp (0.1 .mu.g/kg of body weight) or NaCl once a week. The
animals treated with the erythropoietin analog Aranesp show a
significant survival advantage compared with the animals treated
with sodium chloride (p=0.027; log rank test).
[0103] FIGS. 8-15 show optical microscopic kidney sections 6 weeks
after induction of chronic renal failure in two experimental groups
which were treated either with Aranesp or NaCl and whose
Kaplan-Mayer survival plots are depicted in FIG. 7.
[0104] FIG. 8 shows the histological changes in a Sprague-Dawley
rat with chronic renal failure after NaCl treatment once a week
starting immediately after induction of the chronic renal failure
for a period of 6 weeks. The chronic renal failure results from
removal of the right kidney and ligation of the segmental arteries
which supply the upper and lower renal pole of the left kidney. The
figure shows a medium-sized preglomerular artery with
characteristic onion ring-type vessel wall proliferation associated
with severe hypertensive damage, called Fahr's malignant
nephrosclerosis with endarteritis.
[0105] FIG. 9 shows the histological changes in a Sprague-Dawley
rat with chronic renal failure after NaCl treatment once a week
starting immediately after induction of the chronic renal failure
for a period of 6 weeks. The chronic renal failure results from
removal of the right kidney and ligation of the segmental arteries
which supply the upper and lower renal pole of the left kidney. The
figure shows florid focal-segmental glomerulosclerosis, called
proliferative FSGS (right glomerulus). The other glomerulus (left)
shows ischemic collapse of the loop convolution. A small vessel
with severe endothelial damage is to be seen lower in the picture.
The observed histological changes correspond to hypertensive organ
damage or changes associated with overload nephropathy following
5/6 nephrectomy.
[0106] FIG. 10 shows the histological changes in a Sprague-Dawley
rat with chronic renal failure after NaCl treatment once a week
starting immediately after induction of the chronic renal failure
for a period of 6 weeks. The chronic renal failure results from
removal of the right kidney and ligation of the segmental arteries
which supply the upper and lower renal pole of the left kidney. The
figure shows almost complete sclerosis or destruction of a
glomerulus with compensatory enlargement and pronounced hyalinosis
or fibrinoid necrosis of the relevant afferent arterioles.
[0107] FIG. 11 shows the histological changes in a Sprague-Dawley
rat with chronic renal failure after NaCl treatment once a week
starting immediately after induction of the chronic renal failure
for a period of 6 weeks. The chronic renal failure results from
removal of the right kidney and ligation of the segmental arteries
which supply the upper and lower renal pole of the left kidney. The
figure shows a small preglomerular artery with characteristic onion
ring-like vessel wall proliferation and wall necrosis associated
with severe hypertensive damage, called malignant nephrosclerosis
(compare right of picture). A normal (as yet) undamaged arteriole
is to be seen on the left.
[0108] FIG. 12 shows the histological changes in a Sprague-Dawley
rat with chronic renal failure after Aranesp (EPO) treatment (0.1
.mu.g/kg Aranesp) once a week starting immediately after induction
of the chronic renal failure for a period of 6 weeks. The chronic
renal failure results from removal of the right kidney and ligation
of the segmental arteries which supply the upper and lower renal
pole of the left kidney. The figure shows a normal glomerulus with
delicate afferent vessel. There is no pathological
tubulointerstitial finding.
[0109] FIG. 13 shows the histological changes in a Sprague-Dawley
rat with chronic renal failure after Aranesp (EPO) treatment (0.1
.mu.g/kg Aranesp) once a week starting immediately after induction
of the chronic renal failure for a period of 6 weeks. The chronic
renal failure results from removal of the right kidney and ligation
of the segmental arteries which supply the upper and lower renal
pole of the left kidney. The figure shows a normal glomerulus with
delicate afferent vessel (630.times. magnification). There is no
pathological tubulointerstitial finding.
[0110] FIG. 14 shows the histological changes in a Sprague-Dawley
rat with chronic renal failure after Aranesp (EPO) treatment (0.1
.mu.g/kg Aranesp) once a week starting immediately after induction
of the chronic renal failure for a period of 6 weeks. The chronic
renal failure results from removal of the right kidney and ligation
of the segmental arteries which supply the upper and lower renal
pole of the left kidney. The figure shows a normal glomerulus with
delicate afferent vessel. There is no pathological
tubulointerstitial finding.
[0111] FIG. 15 shows the histological changes in a Sprague-Dawley
rat with chronic renal failure after Aranesp (EPO) treatment (0.1
.mu.g/kg Aranesp) once a week starting immediately after induction
of the chronic renal failure for a period of 6 weeks. The chronic
renal failure results from removal of the right kidney and ligation
of the segmental arteries which supply the upper and lower renal
pole of the left kidney. The figure shows a normal glomerulus with
delicate afferent vessel (630.times. magnification). There is no
pathological tubulointerstitial finding.
EXAMPLE 1
Effect of EPO in Patients with Renal Anemia
[0112] The effect of erythropoietin in patients with renal anemia
(Hb <10.5 g/dl) as a consequence of kidney disease in the
terminal stage (preterminal renal failure; creatinine clearance
<35 ml/min) was investigated. 11 patients were treated
intravenously or subcutaneously with erythropoietin in weekly doses
averaging 5 000 IU of rhEPO (recombinant human erythropoietin) for
a period of at least 8 weeks. After erythropoietin treatment, the
endothelial progenitor cells in the blood of the patients were
investigated over a period of 20 weeks, analyzing endothelial
progenitor cells for their number and their differentiation status
by flow cytometry and a culture assay after 0, 2, 4, 6 and 8
weeks.
[0113] Circulating peripheral blood stem cells (CPBSC) comprise a
small population of cells which express both the CD34 antigen and
the CD45 antigen. An assay has been developed to determine the
number of CPBSC by flow cytometry on the basis of the ISHAGE
guidelines (Sutherland et al., J. Hematother., 5 (1996), 213-226).
This assay was used to determine both the expression pattern of
CD34 and CD45 cells and the morphology of the stem cells. Both the
absolute number of CPBSC per .mu.l and the proportion of CPBSC as a
percentage of the total number of leukocytes was determined in this
way.
[0114] FIG. 1 shows the results of an FACS analysis of circulating
CD34.sup.+ stem cells based on the ISHAGE guidelines.
[0115] FIG. 2 shows the number of CD34.sup.+ stem cells measured by
FACS analysis over a period of 8 weeks.
Cell Culture Assay
[0116] Peripheral blood mononuclear cells (PBMCs) were isolated by
Ficoll density centrifugation from human blood samples in
accordance with the method described in Asahara, Science, 275
(1997), 964-967. The cells were plated out on culture plates with
fibronectin and maintained in EC basal medium. EC basal medium
consists of EBM-2 basal medium (from Clonetics) and EGM-2 Quots
(hEGF; GA-100 (gentamicin, amphotericin-B) FBS, VEGF, hFGF-B
(w/heparin), R.sup.3-IGF-1, ascorbic acid, heparin). After
cultivation for 4 days, nonadherent cells were removed by washing
the plates. The remaining adherent cells were treated with trypsin
and plated out anew. They were then cultivated for a further 3
days. Cells with the endothelial phenotype were identified by
positive staining for two different endothelial markers on day 7
after isolation. These are DiI-labeled acetylated low density
lipoprotein (acLDL-DiI) and Ulex europaeus aglutinin-1 (UEA-1). The
results of this investigation are depicted in FIG. 3.
[0117] The results show that erythropoietin is able to mobilize
endothelial progenitor cells and increase the number of circulating
endothelial progenitor cells. Moreover, functional deficits which
occur in certain pathological states such as renal anemia are
compensated. These results are depicted in FIG. 4.
[0118] It was found by flow cytometry that the number of
circulating CD34.sup.+ stem cells in patients with renal disease in
the terminal stage corresponds to the number of circulating
CD34.sup.+ stem cells in the blood of healthy subjects. After the
erythropoietin treatment is started, the number of CD34.sup.+ stem
cells in the bloodstream increases significantly by more than 50%.
It was determined by using the cell culture assay that there is a
drastic increase in the number of cells developing an endothelial
phenotype after treatment with erythropoietin. In a functional cell
culture assay there was an increase of more than 3-fold in the
greatly impaired ability of endothelial progenitor cells.
EXAMPLE 2
Improved Wound Healing Through Systemic Use of rhEPO
[0119] FVB/N mice were anesthetized by inhalation anesthesia with
isoflorane. The fur on the two rear limbs was removed using a
depilatory lotion and disinfected with 70% alcohol. A sterile 4 mm
disposable biopsy tissue punch was used to make a skin wound on the
right flank of each of the mice. The opposite side served as
internal control. Postoperative antibiotic cover with penicillin G
(20 000 units/kg) was performed once. Throughout the period of
investigation, subcutaneous injections of the recombinant human
erythropoietin analog Aranesp (0.1 .mu.g/kg of body weight) took
place once a week throughout the study period. The treatment
started 7 days before removal of the tissue punch. The results are
depicted in FIG. 5. They show that administration of EPO
considerably expedites the wound healing process.
EXAMPLE 3
Reduction in the Progression of Chronic Renal Failure Through
Erythropoietin Treatment
[0120] 8-week-old Sprague-Dawley rats were anesthetized with
ketamine (120 mg/kg) and Rompun (10 mg/kg). The right kidney was
removed from the rats on day 0 and was fixed in formalin
immediately after removal for histological examination. The
segmental arteries which supply the upper and lower renal pole of
the left kidney were ligated. This results in a renal infarction of
the corresponding areas of the kidney, with only the middle third
of the kidney remaining functional. The rats received subcutaneous
(s.c.) injection of the erythropoietin analog Aranesp in a dose of
0.1 .mu.g/kg of body weight or NaCl as control once a week.
[0121] FIG. 7 shows the Kaplan-Mayer survival plots for both
experimental groups. The Aranesp-treated animals have distinctly
improved survival compared with the control animals treated with
sodium chloride.
[0122] FIGS. 12-15 show that the renal tissue shows no pathological
changes after treatment with erythropoietin, whereas severe
pathological changes are visible after treament with NaCl (compare
FIGS. 8-11). Further histological investigations revealed that a
distinctly greater vessel density (CD31) is to be observed in
Aranesp-treated animals than in animals treated with sodium
chloride (data not shown).
EXAMPLE 4
Reduction in the Progression of Acute Renal Failure
[0123] Sprague-Dawley rats with a body weight of from 250 to 300 g
were employed for this investigation. One of the experimental
groups received Aranesp in a dose of 0.1 .mu.g/kg of body weight
once on the day before induction of the acute kidney failure. The
rats were anesthetized with ketamine (120 mg/kg of body weight) and
Rompun (10 mg/kg). A group of experimental animals which received
s.c. injection of sodium chloride at the same time served as
comparison. The blood flow in the kidney was stopped for 45 minutes
by placing an arterial clamp on the right renal artery. A left
nephrectomy was performed in this time. A sham operation was
performed on a further control group. In this case, the abdomen was
opened, the left renal artery was exposed but the blood supply was
not stopped, and the contralateral right kidney was removed. All
the animals were anesthetized for a period of 60 minutes and
sacrificed 24 hours after the operation.
[0124] The 45-minute ischemia with subsequent reperfusion of the
remaining right kidney led to extensive acute loss of renal
function in the animals treated with sodium chloride. This was
manifested by an increase by a factor of 7 in the serum creatinine
level (p<0.05). By contrast, the animals treated with the
erythropoietin analog Aranesp showed only a four-fold increase in
the serum creatinine level one day after induction of the
ischemia-reperfusion damage. There was no increase in the retention
values in the animals which underwent left nephrectomy and a sham
operation on the right kidney. The results are depicted in FIG.
6.
* * * * *