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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, OBJECTIVE, RESULTS. Meshes: Animals, Apoptosis, Capillaries, Coronary Vessels, Darbepoetin alfa, Disease Models, Animal, Dose-Response Relationship, Drug, Erythropoietin, Heart Failure, Hematinics, Hematocrit, Male, Myocardial Contraction, Neovascularization, Physiologic, Random Allocation, Rats, Rats, Sprague-Dawley, Treatment Outcome.
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Does low-dose erythropoietin improve cardiac function in experimental heart failure without increasing haematocrit? Context: Erythropoietin (EPO) may improve cardiac function and induce neovascularisation in experimental models of chronic heart failure (CHF). However, the increased haematocrit associated with EPO treatment might exert concomitant deleterious effects. To investigate the haematocrit independent effects of EPO on cardiac function. Rats underwent permanent coronary artery ligation to induce myocardial infarction (MI) or sham surgery. Three weeks after MI, rats were randomly allocated to treatment with vehicle (MI) or the long-acting EPO analogue darbepoetin alfa administered in a high (40 microg/kg/3 weeks, MI-EPO-high) or a low-dose (0.4 microg/kg/3 weeks, MI-EPO-low). After 9 weeks, haemodynamic parameters, myocardial histology and Myosin Heavy Chain (MHC) isoforms were determined. High-dose EPO resulted in a significant increase in haematocrit (p<0.01) while low-dose EPO had no effect on haematocrit levels. EPO significantly improved cardiac function in both EPO groups, reflected by increased left ventricular (LV)-developed pressure and improved contractility (dP/dt(max)) and relaxation (dP/dt(min)) indices of the LV at 9-weeks (all p<0.05 compared to MI). The improved cardiac function was associated with increased capillary growth (38% in MI-EPO-high (p<0.01) and 27% in MI-EPO-low (p<0.05)) and an attenuated switch to slow beta-MHC isoforms in both EPO groups.
assistant
EPO improves cardiac function and induces neovascularisation at a dose that does not increase haematocrit, thereby circumventing the possible deleterious effects of increased erythropoiesis. Final Decision: yes