51
|
d'Uscio LV, Smith LA, Katusic ZS. Erythropoietin increases expression and function of vascular copper- and zinc-containing superoxide dismutase. Hypertension 2010; 55:998-1004. [PMID: 20194292 DOI: 10.1161/hypertensionaha.110.150623] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Previous studies have shown that treatment with erythropoietin (EPO) exerts vascular protective effects. The exact mechanisms responsible for these effects are not completely understood. In the present study, we hypothesized that EPO stimulates expression and activity of copper- and zinc-containing superoxide dismutase (SOD1), thus protecting vascular tissue from oxidative stress induced by excessive concentrations of superoxide anions. EPO treatment of wild-type mice for 2 weeks (1000 U/kg, SC, biweekly) significantly increased aortic expression of SOD1. This effect resulted in a significant reduction of superoxide anion concentrations in aorta of treated mice. The ability of EPO to reduce vascular production of superoxide anions was abolished in SOD1-deficient mice. In a mouse model of wire-induced injury of the common carotid artery, treatment of wild-type mice with EPO prevented pathological remodeling, whereas the vascular effect of EPO was absent in SOD1-deficient mice. Our findings demonstrate that treatment with EPO increases vascular expression of SOD1. This effect appears to be an important molecular mechanism underlying vascular protection by EPO.
Collapse
Affiliation(s)
- Livius V d'Uscio
- Departmentsof Anesthesiology and Molecular Pharmacology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | | | | |
Collapse
|
52
|
Kato S, Amano H, Ito Y, Eshima K, Aoyama N, Tamaki H, Sakagami H, Satoh Y, Izumi T, Majima M. Effect of erythropoietin on angiogenesis with the increased adhesion of platelets to the microvessels in the hind-limb ischemia model in mice. J Pharmacol Sci 2010; 112:167-75. [PMID: 20134117 DOI: 10.1254/jphs.09262fp] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Erythropoietin (EPO) has been shown to enhance angiogenesis, but its precise mechanisms of enhancement during ischemia are not fully elucidated. We examined the effect of EPO on blood flow recovery from acute hind-limb ischemia induced by ligation of the femoral artery in male C57Bl/6 mice. The density of microvessels with platelet adhesion in ischemic tissues was assessed by intravital microscopy. Treatment with EPO (100 and 1000 IU/kg, i.p.) restored blood flow in a dose-dependent manner and increased plasma levels of soluble-P-selectin, vascular endothelial growth factor (VEGF), and stromal cell-derived factor (SDF-1). Flow cytometric analysis revealed increased P-selectin expression on platelets in EPO-treated mice compared to PBS-treated mice. Intravital microscopic studies showed that EPO increased density of microvessels with platelet adhesion selectively in the ischemic tissues. Neutralizing antibody against P-selectin reduced the density of microvessels with platelet adhesion enhanced with EPO and impaired blood flow recovery with reductions in VEGF and SDF-1 levels. These results suggest that EPO administration enhances recovery from hind-limb ischemia, and platelet adhesion to the microvessels is a key event to enhance the angiogenesis in the ischemic tissues.
Collapse
Affiliation(s)
- Shintaro Kato
- Department of Pharmacology, Kitasato University School of Medicine, Kitasato, Sagamihara 228-8555, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
53
|
Sims B, Clarke M, Njah W, Hopkins ES, Sontheimer H. Erythropoietin-induced neuroprotection requires cystine glutamate exchanger activity. Brain Res 2010; 1321:88-95. [PMID: 20102705 DOI: 10.1016/j.brainres.2010.01.040] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 01/12/2010] [Accepted: 01/13/2010] [Indexed: 12/25/2022]
Abstract
Erythropoietin (Epo) has been used for many years in neonates for the treatment of anemia of prematurity. Epo has also been proposed for treatment of neonatal brain injury, as mounting evidence suggests neuroprotective properties for Epo. However, Epo's neuroprotective mechanism of action is poorly understood. In this study we hypothesized that Epo may confer neuroprotection by enhancing cellular redox defense brought about by cellular glutathione (GSH). This was examined in cultures of differentiated cortical neural stem cells and using the B104 cell line as model systems. Our data shows that Epo causes a time- and dose-dependent increase in expression and activity of system Xc(-), the transporter responsible for uptake of cystine for the production of glutathione. Cystine uptake increases 3-5 fold in differentiated neural stem cells and B104 cells treated with Epo. Exposure of cells to 100 microM kainate suppressed cellular GSH and caused excitotoxicity, but GSH levels and cell viability were completely restored by Epo in the continued presence of kainate. This rescue effect of Epo vanished if system Xc(-) was inhibited pharmacologically using S4-CPG in the presence of Epo leading to marked cell death of B104 cells and cultured mouse cortical neural stem cells. This could also be achieved using xCT siRNA to decrease xCT expression. This data suggests that system Xc(-) activity and protein expression are positively regulated by Epo directly explaining its neuroprotective effect.
Collapse
Affiliation(s)
- Brian Sims
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | | | | | | |
Collapse
|
54
|
Santhanam AVR, d'Uscio LV, Katusic ZS. Cardiovascular effects of erythropoietin an update. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2010; 60:257-85. [PMID: 21081221 DOI: 10.1016/b978-0-12-385061-4.00009-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Erythropoietin (EPO) is a therapeutic product of recombinant DNA technology and it has been in clinical use as stimulator of erythropoiesis over the last two decades. Identification of EPO and its receptor (EPOR) in the cardiovascular system expanded understanding of physiological and pathophysiological role of EPO. In experimental models of cardiovascular and cerebrovascular disorders, EPO exerts protection either by preventing apoptosis of cardiac myocytes, smooth muscle cells, and endothelial cells, or by increasing endothelial production of nitric oxide. In addition, EPO stimulates mobilization of progenitor cells from bone marrow thereby accelerating repair of injured endothelium and neovascularization. A novel signal transduction pathway involving EPOR--β-common heteroreceptor is postulated to enhance EPO-mediated tissue protection. A better understanding of the role of β-common receptor signaling as well as development of novel analogs of EPO with enhanced nonhematopoietic protective effects may expand clinical application of EPO in prevention and treatment of cardiovascular and cerebrovascular disorders.
Collapse
|
55
|
Sipos PI, Crocker IP, Hubel CA, Baker PN. Endothelial progenitor cells: their potential in the placental vasculature and related complications. Placenta 2009; 31:1-10. [PMID: 19917514 DOI: 10.1016/j.placenta.2009.10.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 09/23/2009] [Accepted: 10/12/2009] [Indexed: 02/04/2023]
Abstract
Endothelial progenitor cells (EPCs) have received significant attention in recent times. A role for EPCs has been suggested in a range of pathologies and some recent studies of EPCs in pregnancy have been published. This review provides a guide to the confusing field of EPCs. Attention is paid to their phenotyping, as although elementary this remains a highly debated topic. The current understanding of different subtypes and physiological role of EPCs in the placenta, fetus and adult are also considered. An overview is given as to role of EPC's in the pathophysiology of different disease states and the possible therapeutic and diagnostic applications expected from EPC-related research in obstetrics.
Collapse
Affiliation(s)
- P I Sipos
- Maternal and Fetal Health Research Group, The University of Manchester, Research Floor, St Mary's Hospital, Oxford Road, Manchester, M13 9WL, UK.
| | | | | | | |
Collapse
|
56
|
Byts N, Sirén AL. Erythropoietin: a multimodal neuroprotective agent. EXPERIMENTAL & TRANSLATIONAL STROKE MEDICINE 2009; 1:4. [PMID: 20142991 PMCID: PMC2816866 DOI: 10.1186/2040-7378-1-4] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Accepted: 10/21/2009] [Indexed: 05/28/2023]
Abstract
The tissue protective functions of the hematopoietic growth factor erythropoietin (EPO) are independent of its action on erythropoiesis. EPO and its receptors (EPOR) are expressed in multiple brain cells during brain development and upregulated in the adult brain after injury. Peripherally administered EPO crosses the blood-brain barrier and activates in the brain anti-apoptotic, anti-oxidant and anti-inflammatory signaling in neurons, glial and cerebrovascular endothelial cells and stimulates angiogenesis and neurogenesis. These mechanisms underlie its potent tissue protective effects in experimental models of stroke, cerebral hemorrhage, traumatic brain injury, neuroinflammatory and neurodegenerative disease. The preclinical data in support of the use of EPO in brain disease have already been translated to first clinical pilot studies with encouraging results with the use of EPO as a neuroprotective agent.
Collapse
Affiliation(s)
- Nadiya Byts
- University of Würzburg, Department of Neurosurgery, Würzburg, Germany
| | - Anna-Leena Sirén
- University of Würzburg, Department of Neurosurgery, Würzburg, Germany
| |
Collapse
|
57
|
Loesch A, Tang H, Cotter MA, Cameron NE. The endothelium of basilar artery of diabetic rat treated with epoetin delta. Angiology 2009; 61:405-14. [PMID: 19815604 DOI: 10.1177/0003319709348294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Erythropoiesis-stimulating agents (ESAs) are used to treat anemia associated with renal failure. It is now known that these agents also show a broad range of cell- and tissue-protective effects. In the current study, we explored whether an ESA, epoetin delta, affects vascular pathology linked to diabetes mellitus (DM). In a rat model of streptozotocin-induced DM, we investigated, by pre-embedding electron-immunocytochemistry, whether epoetin delta affects DM-induced structural changes in cerebrovascular endothelium of the rat basilar artery and influences the subcellular distribution of endothelial nitric oxide synthase (eNOS). Epoetin delta treatment influenced DM-induced changes to the distribution of eNOS in, and the structure of, the endothelial cell. This may indicate potential beneficial effects of epoetin delta on cerebrovascular endothelium and suggests eNOS as a possible target molecule of epoetin delta in DM.
Collapse
Affiliation(s)
- Andrzej Loesch
- Research Department of Inflammation, University College London Medical School, Royal Free Campus, London, United Kingdom.
| | | | | | | |
Collapse
|
58
|
Kurdi M, Booz GW. JAK redux: a second look at the regulation and role of JAKs in the heart. Am J Physiol Heart Circ Physiol 2009; 297:H1545-56. [PMID: 19717737 DOI: 10.1152/ajpheart.00032.2009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A number of type 1 receptor cytokine family members protect the heart from acute and chronic oxidative stress. This protection involves activation of two intracellular signaling cascades: the reperfusion injury salvage kinase (RISK) pathway, which entails activation of phosphatidylinositol 3-kinase (PI3-kinase) and ERK1/2, and JAK-STAT signaling, which involves activation of transcription factor signal transducer and activator of transcription 3 (STAT3). Obligatory for activation of both RISK and STAT3 by nearly all of these cytokines are the kinases JAK1 and JAK2. Yet surprisingly little is known about how JAK1 and JAK2 are regulated in the heart or how they couple to PI3-kinase activation. Although the JAKs are linked to antioxidative stress programs in the heart, we recently reported that these kinases are inhibited by oxidative stress in cardiac myocytes. In contrast, others have reported that cardiac JAK2 is activated by acute oxidative stress by an undefined process. Here we summarize recent insights into the regulation of JAK1 and JAK2. Besides oxidative stress, inhibitory regulation involves phosphorylation, nitration, and intramolecular restraints. Stimulatory regulation involves phosphorylation and adaptor proteins. The net effect of stress on JAK activity in the heart likely represents the sum of both inhibitory and stimulatory processes, along with their dynamic interaction. Thus the regulation of JAKs in the heart, once touted as the paragon of simplicity, is proving rather complicated indeed, requiring a second look. It is our contention that a better understanding of the regulation of this kinase family that is implicated in cardiac protection could translate into effective therapeutic strategies for preventing myocardial damage or repairing the injured heart.
Collapse
Affiliation(s)
- Mazen Kurdi
- Department of Chemistry and Biochemistry, Faculty of Sciences, Lebanese University, Rafic Hariri Educational Campus, Hadath, Lebanon
| | | |
Collapse
|
59
|
Erythropoietin enhances oxygenation in critically perfused tissue through modulation of nitric oxide synthase. Shock 2009; 31:599-606. [PMID: 18838945 DOI: 10.1097/shk.0b013e31818b9cc4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The aim of this study was to investigate the effect of human recombinant erythropoietin (EPO) on the microcirculation and oxygenation of critically ischemic tissue and to elucidate the role of endothelial NO synthase in EPO-mediated tissue protection. Island flaps were dissected from the back skin of anesthetized male Syrian golden hamsters including a critically ischemic, hypoxic area that was perfused via a collateralized vasculature. Before ischemia, animals received an injection of epoetin beta at a dose of 5,000 U/kg body weight with (n = 7) or without (n = 7) blocking NO synthase by 30 mg/kg body weight L-NAME (Nomega-nitro-L-arginine methyl ester hydrochloride). Saline-treated animals served as control (n = 7). Ischemic tissue damage was characterized by severe hypoperfusion and inflammation, hypoxia, and accumulation of apoptotic cell nuclei after 5 h of collateralization. Erythropoietin pretreatment increased arteriolar and venular blood flow by 33% and 37%, respectively (P < 0.05), and attenuated leukocytic inflammation by approximately 75% (P < 0.05). Furthermore, partial tissue oxygen tension in the ischemic tissue increased from 8.2 to 15.8 mmHg (P < 0.05), which was paralleled by a 21% increased density of patent capillaries (P < 0.05) and a 50% reduced apoptotic cell count (P < 0.05). The improved microcirculation and oxygenation were associated with a 2.2-fold (P < 0.05) increase of endothelial NO synthase protein expression. Of interest, L-NAME completely abolished all the beneficial effects of EPO pretreatment. Our study demonstrates that, in critically ischemic and hypoxic collateralized tissue, EPO pretreatment improves tissue perfusion and oxygenation in vivo. This effect may be attributed to NO-dependent vasodilative effects and anti-inflammatory actions on the altered vascular endothelium.
Collapse
|
60
|
Schröder K, Kohnen A, Aicher A, Liehn EA, Büchse T, Stein S, Weber C, Dimmeler S, Brandes RP. NADPH oxidase Nox2 is required for hypoxia-induced mobilization of endothelial progenitor cells. Circ Res 2009; 105:537-44. [PMID: 19679834 DOI: 10.1161/circresaha.109.205138] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RATIONALE Endothelial progenitor cells (EPCs, defined as sca-1(+)flk-1(+)lin(-) mononuclear blood cells) contribute to vascular repair. The role of hypoxia and reactive oxygen species (ROS) in mobilization and function of these cells is incompletely understood. OBJECTIVE We studied the contribution of the NADPH oxidase Nox2, an important vascular source of ROS in this context. METHODS AND RESULTS Hypoxia (10% oxygen) induced the mobilization of EPCs in wild-type (WT) and Nox1 but not in Nox2 knockout (Nox2(y/-)) mice. As erythropoietin (EPO) is known to induce EPC mobilization, we focused on this hormone. EPO induced the mobilization of EPCs in WT and Nox1(y/-) but not Nox2(y/-) animals. Transplantation of bone marrow from Nox2(y/-) mice into WT-mice blocked mobilization in response to hypoxia and EPO, whereas transplantation of WT bone marrow into Nox2(y/-) mice restored mobilization. Reendothelialization of the injured mouse carotid artery was enhanced by hypoxia as well as by EPO, and this effect was not observed in Nox2(y/-) mice or after transplantation of Nox2(y/-) bone marrow. In cultured EPCs from WT but not Nox2(y/-) mice, EPO induced ROS production, migration, and proliferation. EPO signaling involves the STAT5 transcription factor. EPO-induced STAT5-dependent reporter gene expression was absent in Nox2-deficient cells. siRNA against the redox-sensitive phosphatase SHP-2 restored EPO-mediated STAT5 induction and inhibition of SHP-2 restored EPO-induced migration in Nox2-deficient cells CONCLUSIONS We conclude that Nox2-derived ROS inactivate SHP-2 and thereby facilitate EPO signaling in EPCs to promote hypoxia-induced mobilization and vascular repair by these cells.
Collapse
Affiliation(s)
- Katrin Schröder
- Institut für Kardiovaskuläre Physiologie, Johann Wolfgang Goethe-Universität, Theodor-Stern-Kai 7, D-60596 Frankfurt am Main, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
61
|
Sustained release of erythropoietin using biodegradable gelatin hydrogel microspheres persistently improves lower leg ischemia. J Am Coll Cardiol 2009; 53:2378-88. [PMID: 19539150 DOI: 10.1016/j.jacc.2009.02.056] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 02/18/2009] [Accepted: 02/24/2009] [Indexed: 11/24/2022]
Abstract
OBJECTIVES We hypothesized that erythropoietin (EPO)-immersed gelatin hydrogel microspheres (GHM) injected into ischemic legs might continuously release a small amount of EPO to locally stimulate angiogenesis without unfavorable systemic effects. BACKGROUND EPO is a potent angiogenic factor, but its use for relieving ischemic organs is limited because of the untoward systemic erythrogenic effect and its short half-life in plasma. METHODS The right femoral arteries of BALB/c mice were ligated. Recombinant human EPO (5,000 IU/kg)-immersed GHM was injected into the right hind limb muscles (n = 12); the control groups included a saline-injected group (n = 12), an EPO-injected group (n = 8), and an empty GHM-injected group (n = 8). RESULTS Eight weeks later, improvement of blood perfusion to the ischemic limb was significantly augmented in the EPO-GHM group compared with any of the control groups. There was no increase in the hemoglobin level, nor was there any increase in endothelial progenitor cells. However, capillary and arteriolar densities were significantly increased in this group. Although the treatment did not affect the levels of vascular endothelial growth factor or interleukin-1 beta, it up-regulated the EPO receptor and matrix metalloproteinase-2 and activated the downstream signaling of Akt and also endothelial nitric oxide synthase in ischemic limbs, which might have been associated with the evident angiogenic and arteriogenic effects in the present system. CONCLUSIONS The present drug delivery system is suggested to have potential as a novel noninvasive therapy for ischemic peripheral artery disease.
Collapse
|
62
|
Mihov D, Vogel J, Gassmann M, Bogdanova A. Erythropoietin activates nitric oxide synthase in murine erythrocytes. Am J Physiol Cell Physiol 2009; 297:C378-88. [PMID: 19515903 DOI: 10.1152/ajpcell.00543.2008] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Erythropoietin (Epo) is the main regulator of erythrocyte production and a potent cytoprotective factor. It was suggested that some of Epo cytoprotective properties are due to its regulation of nitric oxide (NO) production. Recently, functionally active endothelial type NO synthase (eNOS) was discovered in mature murine and human red blood cells (RBC-eNOS). The goal of the present study was to characterize the effect of physiological and therapeutic doses of Epo on RBC-eNOS function. We found that recombinant human Epo (rHuEpo) binds specifically to mouse erythrocytes. Epo binding sites are not equally distributed through the RBC population but prevail in reticulocytes and young erythrocytes with about 105 receptors/cell, compared with adult and old erythrocytes containing 1-4 receptors/cell. The treatment of mouse erythrocytes with rHuEpo resulted in a time- and dose-dependent upregulation of NO production mediated via activation of the phosphatidylinositol-3-kinase /Akt pathway and RBC-eNOS phosphorylation at Ser-1177. Finally, when erythrocytes were incubated in L-arginine-free medium, rHuEpo treatment resulted in upregulation of superoxide radical production with concomitant shifting of the cellular redox state toward more oxidized state. Epo-induced changes in erythrocyte redox potential were absent in erythrocytes from eNOS-deficient mice.
Collapse
Affiliation(s)
- Deyan Mihov
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zürich Center for Integrative Human Physiology, University of Zürich, Zurich, Switzerland
| | | | | | | |
Collapse
|
63
|
Durrant JR, Seals DR, Connell ML, Russell MJ, Lawson BR, Folian BJ, Donato AJ, Lesniewski LA. Voluntary wheel running restores endothelial function in conduit arteries of old mice: direct evidence for reduced oxidative stress, increased superoxide dismutase activity and down-regulation of NADPH oxidase. J Physiol 2009; 587:3271-85. [PMID: 19417091 DOI: 10.1113/jphysiol.2009.169771] [Citation(s) in RCA: 184] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Habitual aerobic exercise is associated with enhanced endothelium-dependent dilatation (EDD) in older humans, possibly by increasing nitric oxide bioavailability and reducing oxidative stress. However, the mechanisms involved are incompletely understood. EDD was measured in young (6-8 months) and old (29-32 months) cage control and voluntary wheel running (VR) B6D2F1 mice. Age-related reductions in maximal carotid artery EDD to acetylcholine (74 vs. 96%, P < 0.01) and the nitric oxide (NO) component of EDD (maximum dilatation with ACh and l-NAME minus that with ACh alone was -28% vs. -55%, P < 0.01) were restored in old VR (EDD: 96%, NO: -46%). Nitrotyrosine, a marker of oxidative stress, was increased in aorta with age, but was markedly lower in old VR (P < 0.05). Aortic superoxide dismutase (SOD) activity was greater (P < 0.01), whereas NADPH oxidase protein expression (P < 0.01) and activity (P = 0.05) were lower in old VR vs. old cage control. Increasing SOD (with 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl) and inhibition of NADPH oxidase (with apocynin) improved EDD and its NO component in old cage control, but not old VR mice. VR increased endothelial NO synthase (eNOS) protein expression (P < 0.05) and activation (Ser1177 phosphorylation) (P < 0.05) in old mice. VR did not affect EDD in young mice. Our results show that voluntary aerobic exercise restores the age-associated loss of EDD by suppression of oxidative stress via stimulation of SOD antioxidant activity and inhibition of NADPH oxidase superoxide production. Increased eNOS protein and activation also may contribute to exercise-mediated preservation of NO bioavailability and EDD with ageing.
Collapse
Affiliation(s)
- Jessica R Durrant
- Department of Integrative Physiology, University of Colorado at Boulder, 80309, USA
| | | | | | | | | | | | | | | |
Collapse
|
64
|
Abstract
In the haematopoietic system, the principal function of erythropoietin (EPO) is the regulation of RBC production. Consequently, following the cloning of the EPO gene, recombinant human EPO (rHuEPO) forms have been widely used for treatment of anaemia in chronic kidney disease and chemotherapy-induced anaemia in cancer patients. However, a steadily growing body of evidence indicates that the therapeutic benefits of rHuEPO could be far beyond the correction of anaemia. Several articles have been recently published on the tissue-protective, nonhaematological effects of rHuEPO that prevent ischaemia-induced tissue damage in several organs including the kidney.In this review, we focus on nonhaematological effects of rHuEPO in various experimental settings of acute and chronic kidney injury. Because this tissue-protective action of rHuEPO is not the result of correction of anaemia-related tissue hypoxia, we will also discuss potential molecular pathways involved. Finally, we will review the current literature on clinical studies with rHuEPO or analogous substances and progression of chronic kidney disease, and propose possible clinical renoprotective strategies.
Collapse
|
65
|
Toba H, Sawai N, Morishita M, Murata S, Yoshida M, Nakashima K, Morita Y, Kobara M, Nakata T. Chronic treatment with recombinant human erythropoietin exerts renoprotective effects beyond hematopoiesis in streptozotocin-induced diabetic rat. Eur J Pharmacol 2009; 612:106-14. [PMID: 19356735 DOI: 10.1016/j.ejphar.2009.03.065] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2008] [Revised: 03/12/2009] [Accepted: 03/30/2009] [Indexed: 11/28/2022]
Abstract
Recombinant human erythropoietin (rHuEPO), which has been used clinically for the management of renal anemia, is reported to exert pleiotropic beneficial properties against acute ischemic/reperfusion injury in various tissues. To investigate the hypothesis that chronic treatment with rHuEPO might ameliorate diabetic nephropathy beyond hematopoiesis, rHuEPO (150 U/kg, subcutaneously) was administered three times per week to the streptozotocin-induced diabetic rats for 4 weeks. Streptozotocin (65 mg/kg, intravenously) significantly increased urinary protein excretion and collagen deposition in glomerular and tubulointerstitial areas in the kidney, which were attenuated by rHuEPO. rHuEPO normalized the levels of creatinine clearance, serum creatinine, and blood urea nitrogen of diabetic rats. RT-PCR analysis revealed that the expressions of mRNA for transforming growth factor-beta, osteopontin and adhesion molecules were enhanced in the diabetic rat kidney and that the overexpression of these molecules was suppressed by rHuEPO. rHuEPO exerted antioxidant properties by inhibiting renal activation and overexpression of NADPH oxidase. We found the activation of the Akt signaling pathway by the increased expression of phosphorylated Akt and GSK-3beta and a reduction of TUNEL-positive apoptotic cell death in renal tissue from rHuEPO-treated diabetic group. We also demonstrated that rHuEPO restored the endothelial nitric oxide synthase (eNOS) content in the diabetic rat kidney. On the other hand, treatment with rHuEPO did not affect blood glucose level, blood pressure, or hematocrit in diabetic rats. These results suggest that chronic treatment with rHuEPO attenuated renal injury beyond hematopoiesis and regulated apoptosis and eNOS expression, which might be due to the activation of Akt pathway.
Collapse
Affiliation(s)
- Hiroe Toba
- Department of Clinical Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
66
|
Abstract
OBJECTIVE Erythropoietin has recently emerged as a cytoprotective cytokine, which possesses the ability to protect many tissues, including the brain, heart, and kidneys, against ischemia or traumatic injury. We investigated the therapeutic effects of erythropoietin in a murine model of endotoxin shock. DESIGN Prospective, randomized study. SETTING University-based research laboratory. SUBJECTS Male BALB/c mice. INTERVENTIONS Mice intraperitoneally received either lipopolysaccharide (LPS) from Escherichia coli or vehicle. Erythropoietin was administered at a dose of 1000 IU/kg subcutaneously at different time points after LPS administration. We also investigated the effect of erythropoietin on the development of septic shock caused by cecal perforation. MEASUREMENTS AND MAIN RESULTS Treatment of mice with erythropoietin, within 2 hours after LPS administration, improved the mortality rate. Treatment of cecal perforated mice with erythropoietin extended survival by 12 hours, but all animals died by 72 hours in both groups. Erythropoietin attenuated apoptosis in the lungs, liver, small intestine, thymus, and spleen, as assessed by terminal deoxynucleotidyl transferase-mediated nucleotide nick-end labeling staining, active caspase-3 immunostaining and immunoblotting, and measurements of caspase-3/7 activity. Erythropoietin also reduced inducible nitric oxide synthase expression, nitric oxide production, peroxynitrite formation, and tissue hypoxia. In contrast, erythropoietin did not affect the degree of LPS-induced inflammation, as assessed by measurements of blood levels of interleukin-1beta, interleukin-6, tumor necrosis factor-alpha, growth-related oncogene/keratinocyte-derived cytokine, and high mobility group box 1, the phosphorylation levels of nuclear factor kappaB, and the number of neutrophils infiltrating the lungs and the liver. CONCLUSIONS The results of the study demonstrate that administration of a large dose of erythropoietin after induction of experimental endotoxemia improved survival and that the beneficial effects of erythropoietin were associated with inhibition of apoptosis, nitric oxide production, and tissue hypoxia, without alterations in inflammatory responses.
Collapse
|
67
|
Toda N, Ayajiki K, Okamura T. Cerebral Blood Flow Regulation by Nitric Oxide: Recent Advances. Pharmacol Rev 2009; 61:62-97. [DOI: 10.1124/pr.108.000547] [Citation(s) in RCA: 268] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
|
68
|
Abstract
The regenerative capacity of the myocardium and its blood vessels has now been well demonstrated. The cytokines granulocyte colony-stimulating factor, erythropoietin, and stem cell factor may play a role in helping to stimulate cell regeneration under normal physiologic conditions and in patients with myocardial injury. After an ischemic insult, cytokines are released into the peripheral circulation and signal for the mobilization of stem cells. In experimental cardiac injury models, the addition of cytokines has been shown to improve myocardial function with and without the concurrent use of stem cell therapy. Preliminary studies in humans using cytokine therapy alone for treating myocardial infarction have been disappointing. Future studies in patients with myocardial injury need to examine the use of various combinations of cytokines, with and without the addition of intravascular stem cell infusions or direct stem cell injections.
Collapse
|
69
|
Critical role of scavenger receptor-BI–expressing bone marrow–derived endothelial progenitor cells in the attenuation of allograft vasculopathy after human apo A-I transfer. Blood 2009; 113:755-64. [DOI: 10.1182/blood-2008-06-161794] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Abstract
Allograft vasculopathy is the leading cause of death in patients with heart transplantation. Accelerated endothelial regeneration mediated by enhanced endothelial progenitor cell (EPC) incorporation may attenuate the development of allograft vasculopathy. We investigated the hypothesis that modulation of EPC biology and attenuation of allograft vasculopathy by increased high-density lipoprotein cholesterol after human apo A-I (AdA-I) transfer requires scavenger receptor (SR)–BI expression in bone marrow–derived EPCs. After AdA-I transfer, the number of circulating EPCs increased 2.0-fold (P < .001) at different time points in C57BL/6 mice transplanted with SR-BI+/+ bone marrow but remained unaltered in mice with SR-BI−/− bone marrow. The effect of high-density lipoprotein on EPC migration in vitro requires signaling via SR-BI and extracellular signal-regulated kinases and is dependent on increased nitric oxide (NO) production in EPCs. Human apo A-I transfer 2 weeks before paratopic artery transplantation reduced intimal area at day 21 3.7-fold (P < .001) in mice with SR-BI+/+ bone marrow but had no effect in mice with SR-BI−/− bone marrow. AdA-I transfer potently stimulated EPC incorporation and accelerated endothelial regeneration in chimeric SR-BI+/+ mice but not in chimeric SR-BI−/− mice. In conclusion, human apo A-I transfer accelerates endothelial regeneration mediated via SR-BI expressing bone marrow–derived EPCs, thereby preventing allograft vasculopathy.
Collapse
|
70
|
Current World Literature. Curr Opin Nephrol Hypertens 2009; 18:91-3. [DOI: 10.1097/mnh.0b013e32831fd875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
71
|
Abstract
In organ transplantation, blood borne cells and macromolecules (e.g., antibodies) of the host immune system are brought into direct contact with the endothelial cell lining of graft vessels. In this location, graft endothelial cells play several roles in allograft rejection, including the initiation of rejection responses by presentation of alloantigen to circulating T cells; the development of inflammation and thrombosis; and as targets of injury and agents of repair.
Collapse
|
72
|
Abstract
In organ transplantation, blood borne cells and macromolecules (e.g., antibodies) of the host immune system are brought into direct contact with the endothelial cell lining of graft vessels. In this location, graft endothelial cells play several roles in allograft rejection, including the initiation of rejection responses by presentation of alloantigen to circulating T cells; the development of inflammation and thrombosis; and as targets of injury and agents of repair.
Collapse
|
73
|
Beirão I, Lobato L, Moreira L, Mp Costa P, Fonseca I, Cabrita A, Porto G. Long-term treatment of anemia with recombinant human erythropoietin in familial amyloidosis TTR V30M. Amyloid 2008; 15:205-9. [PMID: 18925459 DOI: 10.1080/13506120802195840] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Familial amyloidosis or familial amyloid polyneuropathy (FAP) TTR V30M is a hereditary disease presented, in most cases, as a sensorimotor and autonomic neuropathy. Normocytic and normochromic anaemia was found in 24.8% of symptomatic FAP patients associated to lower serum erythropoietin (Epo) levels. Erythropoietin has been reported as efficient in anaemia correction in this disease. To evaluate the tolerance and efficacy of this treatment, a retrospective longitudinal study with 24 patients was undertaken. Patients were followed for at least 6 months. Haemoglobin, hematocrit, iron status, serum creatinine and urea and r-HuEPO doses were monitored, at 0, 3 months, 6 months and at the end of the follow-up. Long-term use of r-HuEPO proved to be efficient in the treatment of anaemia in familial amyloidosis TTR V30M and, despite the disease progression, no resistance cases to this treatment were observed. Positive side effects, like improvement on orthostatic hypotension symptoms and well-being sensation, contributing to confirm erythropoietin as a drug of choice to treat anaemia in amyloidosis TTR V30M.
Collapse
|
74
|
Abstract
It is common knowledge that ischemic stroke has major social and economic consequences. However, until now, translation of experimental studies into clinical reality has been sorely lacking. So far, most studies have focused on acute stroke outcome and early treatment paradigms affording neuroprotection. It is increasingly recognized that it will be necessary to harness the capacity of the brain for neuroregeneration to improve longer-term outcome. Endothelial nitric oxide synthase (eNOS) is emerging as a key target in molecular stroke research. eNOS ameliorates acute ischemic injury and promotes recovery following cerebral ischemia. This review summarizes the effects of eNOS on the regulation of cerebral blood flow, hemostasis, inflammation, angiogenesis as well as neurogenesis. The possible impact on stroke prevention as well as on strategies aimed at improving long-term stroke outcome are discussed.
Collapse
Affiliation(s)
- Karen Gertz
- Charité Universitätsmedizin Berlin, Klinik und Poliklinik für Neurologie, Abteilung für Experimentelle Neurologie, Charitéplatz 1, 10117 Berlin, Germany
| | - Matthias Endres
- Charité Universitätsmedizin Berlin, Klinik und Hochschulambulanz für Neurologie und Klinische Neurophysiologie, Campus Benjamin Franklin and Center for Stroke Research Berlin, Charitéplatz 1, 10117 Berlin, Germany
| |
Collapse
|
75
|
Santhanam AVR, d’Uscio LV, Peterson TE, Katusic ZS. Activation of endothelial nitric oxide synthase is critical for erythropoietin-induced mobilization of progenitor cells. Peptides 2008; 29:1451-5. [PMID: 18448202 PMCID: PMC2570495 DOI: 10.1016/j.peptides.2008.03.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Revised: 03/13/2008] [Accepted: 03/14/2008] [Indexed: 11/20/2022]
Abstract
The present study aimed to define the ability of erythropoietin (EPO) to mobilize hematopoietic stem cells (c-kit(+)/sca-1(+)/lin-1(-); KSL-cells) and hematopoietic progenitor cells (CD34(+) cells), including vascular endothelial growth factor receptor 2 expressing hematopoietic progenitor cells (CD34(+)/Flk-1(+) cells). We also sought to determine the role of endothelial nitric oxide synthase (eNOS) in EPO-induced mobilization. Wild type (WT) and eNOS(-/-) mice were injected bi-weekly with recombinant erythropoietin (EPO, 1000U/kg, s.c.) for 14 days. EPO increased the number of KSL, CD34(+), CD34(+)/Flk-1(+) cells in circulating blood of wild type mice. These effects of EPO were abolished in eNOS(-/-) mice. Our results demonstrate that, EPO stimulates mobilization of hematopoietic stem and progenitor cells. This effect of EPO is critically dependent on activation of eNOS.
Collapse
Affiliation(s)
| | | | | | - Zvonimir S Katusic
- Author for Correspondence: Dr. Zvonimir S. Katusic, Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905, , Phone: 507-255-5156, Fax: 507-255-7300
| |
Collapse
|
76
|
d'Uscio LV, Katusic ZS. Erythropoietin increases endothelial biosynthesis of tetrahydrobiopterin by activation of protein kinase B alpha/Akt1. Hypertension 2008; 52:93-9. [PMID: 18519842 PMCID: PMC2646900 DOI: 10.1161/hypertensionaha.108.114041] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Tetrahydrobiopterin (BH(4)) is an essential cofactor required for enzymatic activity of endothelial NO synthase. Recently, it has been shown that vascular protective effects of erythropoietin (EPO) are dependent on activation of endothelial NO synthase. Therefore, our objective was to characterize the effect of EPO on the biosynthesis of BH(4) in the vascular wall. Incubation of isolated C57BL/6J mouse aortas for 18 hours with recombinant human EPO (1 to 50 U/mL) caused a concentration-dependent increase in intracellular BH(4) levels and activity of GTP-cyclohydrolase I. Maximal biosynthesis of BH(4) was detected at therapeutic concentrations of 5 U/mL. Removal of the endothelium abolished EPO-induced biosynthesis of BH(4) demonstrating that the vascular endothelium is a major source of BH(4). Treatment with a selective phosphatidylinositol 3-kinase inhibitor wortmannin significantly reduced BH(4) biosynthesis stimulated by EPO. The stimulatory effect of EPO on vascular GTP-cyclohydrolase I activity, BH(4) production, and phosphorylation of endothelial NO synthase was also detected in vivo in mice treated with recombinant human EPO. These effects of EPO were abolished in protein kinase Balpha/Akt1-deficient mice. In addition, EPO significantly increased systolic blood pressure and the number of circulating platelets in Akt1-deficient mice. Our results demonstrate that EPO stimulates biosynthesis of BH(4) in vascular endothelium and that the increase in BH(4) levels is caused by de novo biosynthesis of BH(4) via the phosphatidylinositol 3-kinase/Akt1 pathway. This effect is most likely designed to provide optimal intracellular concentration of the cofactor necessary for EPO-induced elevation of endothelial NO synthase activity.
Collapse
Affiliation(s)
- Livius V d'Uscio
- Department of Anesthesiology and Molecular, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
| | | |
Collapse
|
77
|
Abstract
The major physiological function of erythropoietin (EPO) is thought to be the induction of erythropoiesis. However, a growing body of evidence indicates that EPO as well as recombinant human erythropoietin (rHuEPO) and its analogues have tissue-protective effects and prevent tissue damage during ischaemia. This mini review summarizes the present knowledge on protective vascular effects of EPO and discusses the potential underlying mechanisms.
Collapse
Affiliation(s)
- D Fliser
- Saarland University Medical Centre, Homburg, Germany.
| | | |
Collapse
|
78
|
Rodrigue ME, Brochu I, D' orleans-Juste P, Larivierea R, Lebel M. Effect of erythropoietin on blood pressure and on the vascular endothelial ET-1/ETB receptor system. Am J Hypertens 2008; 21:639-43. [PMID: 18437122 DOI: 10.1038/ajh.2008.37] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Recombinant human erythropoietin (rhEPO) increases blood pressure (BP) and the vascular production of endothelin-1 in renal failure rats. This study was designed to investigate the effect of rhEPO on BP and on the ET-1/ET(B)R system in rats with normal renal function. To further characterize the effect of rhEPO on the ET-1/ET(B)R system, we also studied heterozygous (+/-) ET(B)R knockout (KO) mice. METHODS The animals received either the vehicle or rhEPO (100 U/kg subcutaneously three times per week). ET(B)R(+/-) mice were compared with ET(A)R(+/-) and wild-type (WT) mice. In rats, the ET(B)R mRNA expression was assessed in blood vessels as well as the vascular ET(B)R density using immunohistochemistry. In mice, ET-1 concentration was measured in the thoracic aorta. RESULTS RhEPO administration increased hematocrit levels in all treated animals. This therapy had no effect on BP in normal rats, but it did increase vascular and renal cortex ET(B)R mRNA expression. Immunohistochemistry confirmed that the ET(B)R density was increased in blood vessel endothelium in these normal rats. In contrast, rhEPO increased BP in ET(B)R(+/-) mice and this pressor effect was associated with higher ET-1 concentrations in the thoracic aorta. CONCLUSIONS RhEPO exerts a pleotropic effect on the endothelial ET-1/ET(B)R system. The increase in endothelial ET(B)R expression may contribute to maintaining normal BP during rhEPO administration in normal animals. Conversely, conditions with deficient ET(B)R expression, such as in ET(B)R(+/-) mice, may lead to hypertension while receiving the same therapy.
Collapse
|
79
|
Gluhovschi G, Gluhovschi C, Bob F, Velciov S, Trandafirescu V, Petrica L, Bozdog G. Multiorgan-protective actions of blockers of the renin-angiotensin system, statins and erythropoietin: common pleiotropic effects in reno-, cardio- and neuroprotection. Acta Clin Belg 2008; 63:152-69. [PMID: 18714846 DOI: 10.1179/acb.2008.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Renal diseases induce nephroprotective measures that may affect the heart, brain and other organs. In addition, many cardiovascular and neurological diseases are accompanied by renal lesions. For these reasons, multiorgan-protective measures, including cardio-, reno- and neuro-protective measures, are necessary to treat these diseases. The drugs used in nephrology are often pleiotropic. Although they usually address a single organ or tissue, many of them have complex actions that may provide multiorgan-protection. The present paper aims to review 3 classes of drugs that are commonly prescribed in nephrological practice: statins, RAS blockers (such as ACEIs and ARBs) and erythropoietin (EPO). This paper highlights the renoprotective actions, as well as those that are protective of the heart, brain and other organs, of these drugs at the cellular and molecular level. Their protective actions are attributable to their main effects and pleiotropic effects. The protective pleiotropic actions of these drugs may be exerted on multiple organs, making them multiorgan-protective. Another objective is to analyse the shared multiorgan-protective pleiotropic effects of RAS blockers (ACEIs and ARBs), statins and erythropoietin. This will allow for the practical association of the main renoprotective drugs with multiorgan protection.
Collapse
Affiliation(s)
- G Gluhovschi
- Nephrology Department, University of Medicine and Pharmacy Victor Babes, Timisoara, Romania.
| | | | | | | | | | | | | |
Collapse
|
80
|
Ruifrok WPT, de Boer RA, Westenbrink BD, van Veldhuisen DJ, van Gilst WH. Erythropoietin in cardiac disease: new features of an old drug. Eur J Pharmacol 2008; 585:270-7. [PMID: 18407263 DOI: 10.1016/j.ejphar.2008.01.054] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2007] [Revised: 12/21/2007] [Accepted: 01/22/2008] [Indexed: 12/11/2022]
Abstract
Erythropoietin is a haematopoietic hormone with extensive non-haematopoietic effects. The discovery of an erythropoietin receptor outside the haematopoietic system has fuelled the research into the beneficial effects of erythropoietin for various conditions, predominantly in cardiovascular disease. Experimental evidence has revealed the cytoprotective and angiogenic properties of erythropoietin and it seems that the erythropoietin-erythropoietin receptor system provides a powerful backbone against acute and chronic myocardial ischemia, each gaining from the different properties of erythropoietin. Clinical trials in which erythropoietin was titrated to achieve certain haematocrit levels have generated equivocal results. It has been suggested that a (too) high haematocrit is undesirable in cardiovascular disease. We have shown that intermittent (low-dose) erythropoietin administration, that does not increase haematocrit substantially, suffices to activate the beneficial downstream pathways of erythropoietin. We postulate that intermittent administration or a lower than conventional dose of erythropoietin, not only aimed at increasing haemoglobin at high levels, will provide powerful cellular protection and will improve cardiac outcome, without the side effects of erythropoietin associated with increased haematocrit.
Collapse
Affiliation(s)
- Willem-Peter T Ruifrok
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
| | | | | | | | | |
Collapse
|
81
|
Westenbrink BD, Oeseburg H, Kleijn L, van der Harst P, Belonje AMS, Voors AA, Schoemaker RG, de Boer RA, van Veldhuisen DJ, van Gilst WH. Erythropoietin stimulates normal endothelial progenitor cell-mediated endothelial turnover, but attributes to neovascularization only in the presence of local ischemia. Cardiovasc Drugs Ther 2008; 22:265-74. [PMID: 18327705 DOI: 10.1007/s10557-008-6094-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 01/31/2008] [Indexed: 10/22/2022]
Abstract
PURPOSE We aimed to evaluate whether ischemia is required for erythropoietin (EPO) induced stimulation of endothelial progenitor cells (EPCs) and their related effects on endothelial and cardiac function. METHODS Bone marrow of rats was replaced by transgenic cells to allow tracking of EPCs. Ischemic heart failure was induced by left coronary artery ligation to induce myocardial infarction (MI) and control rats received a sham procedure. Three weeks after surgery, rats were randomized to receive EPO (darbepoetin alfa 40 microg/kg per 3 weeks) or vehicle and were sacrificed 9 weeks after surgery. RESULTS In all treated groups, EPO significantly increased circulating EPCs and their incorporation into the endothelium of the ischemic and non-ischemic hearts as well as in the control organs; kidney and liver. This was associated with significantly improved endothelial function, which was strongly correlated with circulating EPCs (R = 0.7, p < 0.01). However, additional EPCs preferentially homed to the ischemic MI borderzone (p < 0.01) resulting in specific EPO-induced improvement of cardiac microvascularization and performance only in ischemic hearts (all p < 0.05). The differential stimulation of neovascularization by EPO was associated with increased EPO-receptor and VEGF expression in ischemic hearts only. CONCLUSIONS In general, EPO stimulates normal endothelial progenitor cell-mediated endothelial turnover, but improves cardiac microvascularization and function only in the presence of ischemia.
Collapse
Affiliation(s)
- B Daan Westenbrink
- Department of Cardiology, Thoraxcenter, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
82
|
Aydin Z, Duijs J, Bajema IM, van Zonneveld AJ, Rabelink TJ. Erythropoietin, progenitors, and repair. Kidney Int 2007:S16-20. [PMID: 17943139 DOI: 10.1038/sj.ki.5002483] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The erythropoietin-erythropoietin-receptor (EPO-EPO-R) system has recently been identified as an important cellular survival pathway. Its presence has also been demonstrated in the kidney and identified as a therapeutic target to prevent loss of renal function. Part of the protective effects may be related to the action of erythropoietin on endothelial function and expansion of endothelial progenitor cells. This paper reviews current evidence for involvement of these mechanisms in EPO-mediated renoprotection.
Collapse
Affiliation(s)
- Z Aydin
- Department of Nephrology, Leiden University Medical Centre, Leiden, The Netherlands
| | | | | | | | | |
Collapse
|
83
|
|