Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0151744 (myocardial ischemia)
 31,282 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Autologous blood (AB) donation can minimize exposure to allogeneic blood in patients scheduled for coronary artery bypass graft (CABG) surgery. During AB donation in this group of patients, minimization of the accompanying decrease in hemoglobin (Hb) levels is important to reduce the risk of provoking silent myocardial ischemia and/or arrhythmias. Recombinant human erythropoietin (rHuEPO) has been used to facilitate AB donation and minimize the accompanying decrease in Hb levels in patients scheduled for cardiac surgery. In 24 patients scheduled for CABG surgery, once-weekly subcutaneous (s.c.) administration of rHuEPO (epoetin alfa 400 IU/kg) plus oral iron supplementation for 4 weeks prior to surgery caused marked stimulation of erythropoiesis and significantly increased collection of autologous red blood cells (RBCs) compared with oral iron alone. Furthermore, epoetin alfa minimized the decrease in Hb levels associated with AB donation and significantly attenuated allogeneic blood requirements by facilitating the collection of 4 AB units prior to surgery. During AB donation, no changes in the incidence or severity of ischemic attacks or ST-segment changes were observed using electrocardiographic monitoring. Epoetin alfa was well tolerated. Once-weekly s.c. administration of epoetin alfa for 4 weeks therefore represents a practical means of facilitating AB donation by patients scheduled for CABG surgery.
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PMID:Subcutaneous epoetin alfa as an adjunct to autologous blood donation before elective coronary artery bypass graft surgery. 872 87

It has been suggested that normalization of haemoglobin with epoetin in anaemic chronic renal failure (CRF) patients might result in even greater benefits than those currently achieved with partial haemoglobin correction. Four prospective randomized trials recently examined this hypothesis. The Scandinavian Multicentre Trial, which was completed in February 1998, included 416 haemodialysis, continuous ambulatory peritoneal dialysis and pre-dialysis patients. Preliminary analysis of the data found no differences with respect to safety between patients treated to achieve subnormal haemoglobin (9.0-12.0 g/dl) and those in whom haemoglobin was normalized (13.5-16.0 g/dl). The Canadian Multicentre Trial included 159 haemodialysis patients with asymptomatic left ventricular (LV) dysfunction. In patients with a normal LV cavity volume at enrolment, the change in LV cavity volume at 48 weeks was significantly greater in the control group (target haemoglobin 9.5-10.5 g/dl) than in the intervention group (target haemoglobin 13.0-14.0 g/dl). The Normal Hematocrit Cardiac Trial in the US included 1233 haemodialysis patients with clinically evident ischaemic heart disease or congestive heart failure. The trial was stopped in 1996 after an interim analysis showed increased mortality in the intervention group (target haematocrit 42%) compared with the control group (target haematocrit 30%). The higher haematocrit values themselves, however, did not appear to be responsible for the differences in mortality, as the mortality rates within each group decreased with increasing haematocrit. Nonetheless, until evidence is available from other trials demonstrating a benefit of normalizing haemoglobin, it has been recommended that a target haematocrit value of 42% be avoided in haemodialysis patients with clinically evident ischaemic heart disease or congestive heart failure. Further studies are also required to determine whether increasing haemoglobin to normal may prove to be beneficial in other patient groups. The Spanish Quality of Life Study of 134 haemodialysis patients found a significant improvement in all quality-of-life parameters when haemoglobin was increased to a mean of 12.5 g/dl. The investigators suggested that in patients without severe co-morbidity, the target haemoglobin should be as close to normal as possible.
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PMID:Normalization of haemoglobin: why not? 1033 71

Despite the use of recombinant human erythropoietin (rh-EPO, epoetin) for more than a decade in treating renal anaemia, there is still considerable debate over optimal target haemoglobin (Hb) levels. Current European and North American guidelines that are based on decade-old trials aim for partial anaemia correction, with a subnormal target Hb concentration. More recent randomized clinical trials examining the effect of normalizing Hb levels have produced conflicting results. A study in the USA, in patients with existing congestive heart failure or ischaemic heart disease, showed an unexpected rise in cardiac mortality and haemodialysis access failure with higher Hb levels. In contrast, three other studies (in Australia, Spain and Canada) that normalized Hb levels in healthier dialysis patients observed improvements in quality of life and exercise capacity and a slower progression of left ventricular dilatation, without an unacceptable increase in the incidence of adverse effects. These studies indicate that, while higher Hb levels may be detrimental to patients with pre-existing cardiac disease, healthier patients benefit from normalized Hb levels. Thus, there is no clear scientific rationale for setting a single Hb target for all patients, and individualized treatment targets would appear to be a more logical and patient-centred approach.
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PMID:A rationale for an individualized haemoglobin target. 1209 94

Erythropoietin (Epo) is a hormone regulating proliferation and differentiation of erythroid cells. The hypothesis that hematopoietic and endothelial cells share a common hemangioblast progenitor among others is based on the finding that both cell lineages express cell surface antigens like CD31 and CD34. In this study we investigated the angiogenic potential of recombinant human erythropoietin (rHuEpo) on endothelial cells derived from human adult myocardial tissue. In addition, we compared the angiogenic potential of rHuEpo to that of other cytokines (VEGF, aFGF) and combinations of growth factors. Samples of myocardial tissue (cardiac auricle) were obtained during coronary bypass surgery, embedded in a fibrin gel matrix, and cultured for 21 days. Capillary sprouting was measured with an eye-piece graticule under an inverted-phase contrast microscope. Tube-forming endothelial cells were characterized by immunohistochemistry and RT-PCR. Using a concentration of 2.5 U/ml, we found that rHuEpo stimulates capillary outgrowth up to 220%, compared to the nonstimulated physiological outgrowth. Epo therefore exhibits the same angiogenic potential on endothelial cells in our in vitro assay as VEGF(165) (230% increase). Erythropoietin stimulates capillary outgrowth in an in vitro angiogenesis assay using adult human myocardial tissue. This implies a role of erythropoietin in vasoproliferative processes. rHuEpo may serve as a direct angiogenic substance in patients with ischemic heart disease.
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PMID:Erythropoietin and VEGF exhibit equal angiogenic potential. 1220 56

Erythropoietin (EPO), originally identified for its critical hormonal role in promoting erythrocyte survival and differentiation, is a member of the large and diverse cytokine superfamily. Recent studies have identified multiple paracrineautocrine functions of EPO that coordinate local responses to injury by maintaining vascular autoregulation and attenuating both primary (apoptotic) and secondary (inflammatory) causes of cell death. Experimental evidence also supports a role for EPO in repair and regeneration after brain and spinal cord injury, including the recruitment of stem cells into the region of damage. Tissue expression of the EPO receptor is widespread, especially during development, and includes the heart. However, it is currently unknown as to whether EPO plays a physiological function in adult myocardial tissue. We have assessed the potential protective role of EPO in vitro with adult rat cardiomyocytes, and in vivo in a rat model of myocardial infarction with reperfusion. The results show that EPO markedly prevents the apoptosis of cultured adult rat myocardiocytes subjected to 28 h of hypoxia (approximately 3% normal oxygen). Additional studies employing a rat model of coronary ischemia-reperfusion showed that the administration of recombinant human EPO (5,000 units/kg of body weight; i.p. daily for 7 days) reduces cardiomyocyte loss by approximately 50%, an extent sufficient to normalize hemodynamic function within 1 week after reperfusion. These observations not only suggest a potential therapeutic role for recombinant human EPO in the treatment of myocardial ischemia and infarction by preventing apoptosis and attenuating postinfarct deterioration in hemodynamic function, but also predict that EPO is likely a tissue-protective cytokine in other organs as well.
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PMID:Recombinant human erythropoietin protects the myocardium from ischemia-reperfusion injury and promotes beneficial remodeling. 1266 57

Erythropoietin (EPO) has been shown to protect neurons from ischemic stroke, but can also increase thrombotic events and mortality rates in patients with ischemic heart disease. We reasoned that benefits of EPO might be offset by increases in hematocrit and evaluated the direct effects of EPO in the ischemic heart. We show that preconditioning with EPO protects H9c2 myoblasts in vitro and cardiomyocytes in vivo against ischemic injury. EPO treatment leads to significantly improved cardiac function following myocardial infarction. This protection is associated with mitigation of myocyte apoptosis, translating into more viable myocardium and less ventricular dysfunction. EPO-mediated myocyte survival appears to involve Akt activation. Importantly, cardioprotective effects of EPO were seen without an increase in hematocrit (eliminating oxygen delivery as an etiologic factor in myocyte survival and function), demonstrating that EPO can directly protect the ischemic and infarcted heart.
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PMID:A novel protective effect of erythropoietin in the infarcted heart. 1452 37

Erythropoietin has recently been shown to have effects beyond hematopoiesis such as prevention of neuronal and cardiac apoptosis secondary to ischemia. In this study, we evaluated the in vivo protective potential of erythropoietin in the reperfused rabbit heart following ventricular ischemia. We show that "preconditioning" with erythropoietin activates cell survival pathways in myocardial tissue in vivo and adult rabbit cardiac fibroblasts in vitro. These pathways, activated by erythropoietin in both whole hearts and cardiac fibroblasts, are also activated acutely by ischemia/reperfusion injury. Moreover, in vivo studies indicate that erythropoietin treatment either prior to or during ischemia significantly enhances cardiac function and recovery, including left ventricular contractility, following myocardial ischemia/reperfusion. Our data indicate that a contributing in vivo cellular mechanism of this protection is mitigation of myocardial cell apoptosis. This results in decreased infarct size as evidenced by area at risk studies following in vivo ischemia/reperfusion injury, translating into more viable myocardium and less ventricular dysfunction. Therefore, erythropoietin treatment may offer novel protection against ischemic heart disease and may act, at least in part, by direct action on cardiac fibroblasts and myocytes to alter survival and ventricular remodeling.
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PMID:Cardioprotective effects of erythropoietin in the reperfused ischemic heart: a potential role for cardiac fibroblasts. 1502 May 86

Erythropoietin is protective against cardiac ischemia, but the underlying mechanisms are unknown. We determined whether erythropoietin (0.5 - 10.0 U/ml) confers acute cardioprotection in infant rabbit hearts and the contribution of protein kinases, nitric oxide synthase and potassium channels to the underlying mechanism. Hearts from normoxic infant New Zealand White rabbits (n=8/group) were isolated and perfused in the Langendorff mode. Biventricular function was recorded under steady-state conditions prior to 30 min global no-flow ischemia and 35 min reperfusion. Administration of erythropoietin for 15 min immediately prior to ischemia resulted in a concentration-dependent increase in recovery of left and right ventricular developed pressure in rabbit hearts following myocardial ischemia and reperfusion. The optimal concentration of erythropoietin that afforded maximum recovery of developed pressure was manifest at 1.0 U/ml. Erythropoietin (1.0 U/ml) treatment resulted in phosphorylation of PKC, p38 MAP kinase and p42/44 MAP kinase. The cardioprotective effects of erythropoietin were abolished by the protein kinase inhibitors SB203580 (p38 MAP kinase), PD98059 (p42/44 MAP kinase) and chelerythrine (PKC) as well as the potassium channel blockers glibenclamide, HMR 1098, 5-HD and Paxilline. Nitrite and nitrate release from hearts before (2.3 +/- 0.9 nmol/min/g) and after (2.4 +/- 1.9 nmol/min/g) 15 min treatment with erythropoietin (1.0 U/ml) were not different. L-NAME and L-NMA did not block the cardioprotective effect of erythropoietin. We conclude the rapid activation of potassium channels and protein kinases by erythropoietin represents an important new mechanism for increasing cardioprotection.
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PMID:Acute cardioprotective effects of erythropoietin in infant rabbits are mediated by activation of protein kinases and potassium channels. 2751 2

Understanding the tissue distribution of erythropoietin receptors and cellular actions of erythropoietic agents may facilitate the development of wider applications for these compounds. Erythropoietin receptors have been identified in the central nervous system (CNS), retina, heart, vascular endothelium, kidney, lung, liver, gastrointestinal and reproductive tracts, and erythroid bone marrow precursors. Potential benefits of erythropoietic agents in several therapeutic areas may result from actions other than hematopoiesis stimulation. Their hematopoietic effects may also have broader applications in treating anemia of the elderly and non-chemotherapy (CT)-related anemia in patients with cancer. Furthermore, because hypoxic tumor cells tend to be more resistant to radiation therapy (RT) and some forms of CT, and more aggressive than normoxic cells, increased oxygenation resulting from anemia correction may increase RT and CT sensitivity, possibly impacting treatment outcomes. However, clinical studies addressing this hypothesis have conflicting results. Preliminary evidence suggests erythropoietin has CNS neuroprotective effects, including potential clinical benefits in ischemic stroke. In addition, data suggest that erythropoietin (epoetin alfa) may attenuate declines in cognitive function during CT for early-stage breast cancer. Erythropoietin may have benefits in retinal disease, peripheral neuropathy, and myocardial ischemia. Thus, accumulating evidence suggests that erythropoietic agents may have clinical utility outside CT-related anemia.
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PMID:Preclinical and clinical studies: a preview of potential future applications of erythropoietic agents. 1576 75

Erythropoietin (EPO), known for its role in stimulating erythropoiesis, has recently been shown to have a cardio-protective effect in animal models of myocardial ischemia-reperfusion (I-R) injury. The mechanism of the cardio-protective effect of EPO is unclear. Part of the mechanism for EPO-induced cardio-protection may involve inhibition of myocardial apoptosis and preservation of ATP levels in the ischemic myocardium. We studied the expression of heat shock protein 70 (Hsp70) and its possible links to the cardio-protective effect of EPO. A rat model of myocardial I-R injury was established by ligating the left descending coronary artery for 30 min and then reperfusing for 2 hr. Recombinant human EPO (rhEPO) was injected ip 24 hr before the ligation. The myocardial infarct size and the area at risk of ischemia were measured by staining with triphenyltetrazolium chloride (TTC) and Evans blue dye. Expression of Hsp70 in the left ventricle was analyzed by ELISA and that of nuclear factor-kappaB (NF-kappaB) was analyzed by electrophoretic mobility shift assay (EMSA). The results showed that a single ip injection of 3,000 units/kg of rhEPO at 24 hr pre-ligation enhanced the expression of Hsp70 and diminished the expression of NF-kappaB in rat myocardium, and that the myocardial infarct induced by I-R injury was remarkably reduced in size, compared to control rats that received an ip saline injection at 24 hr pre-ligation.
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PMID:Recombinant human erythropoietin pretreatment attenuates myocardial infarct size: a possible mechanism involves heat shock Protein 70 and attenuation of nuclear factor-kappaB. 1594 80


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