Abstract
Recombinant human erythropoietin (rHuEPO) has been used as a performance‐enhancing agent by athletes in a variety of sports. The resulting increase in hematocrit levels leads to increased blood viscosity and can affect blood flow, potentially increasing the athlete's risk of developing health complications. However, the actual effects of using rHuEPO on microvascular blood flow and post‐occlusive reactive hyperemia are currently unknown. We therefore evaluated the effect of rHuEPO on the cutaneous microcirculation in well‐trained cyclists using laser speckle contrast imaging (LSCI). This study was part of a randomized, double‐blind, placebo‐controlled, parallel trial designed to investigate the effects of rHuEPO in 47 well‐trained adult cyclists (age 18–50 years). Subjects received a weekly dose of either rHuEPO or placebo for 8 weeks, and LSCI was performed at baseline, after a maximal exercise test in week 6, and before maximal exercise in week 8. Endpoints included basal blood flux, maximum post‐occlusion reperfusion, and time to return to baseline. Despite an increase in hematocrit levels in the rHuEPO‐treated group, we found no statistically significant difference in microvascular function measured between the rHuEPO‐treated group and the placebo group. Our results suggest that the increased hematocrit levels in rHuEPO‐treated well‐trained cyclists are not associated with changes in microvascular blood flow or post‐occlusive reactive hyperemia measured using LSCI.
Highlights
The protein erythropoietin (EPO) is produced in the kidney and stimulates erythropoiesis in the bone marrow
We used laser speckle contrast imaging (LSCI) to study the effect of Recombinant human EPO (rHuEPO) injections and maximal exercise on the microvasculature and post-occlusive reactive hyperemia in well-trained cyclists
RHuEPO caused a significant increase in hematocrit levels; in contrast, we found no difference between the rHuEPO and placebo groups at 8 weeks with respect to blood flow in the cutaneous microvasculature
Summary
The protein erythropoietin (EPO) is produced in the kidney and stimulates erythropoiesis in the bone marrow. EPO production is often greatly reduced in patients with end-stage renal disease, leading to severe anemia. Recombinant human EPO (rHuEPO) is a biologically synthesized protein that helps maintain steady-state erythropoiesis (Eschbach et al 1989); in 1989, rHuEPO became available for clinical use in patients with chronic renal failure. Despite conflicting evidence with respect to its efficacy, rHuEPO has been used as a performance-enhancing agent by athletes in a variety of sports, including elite cycling. The use of rHuEPO by athletes is generally based on the notion that increasing hematocrit levels (i.e., increasing the ratio between the volume of red blood cells and total blood volume) increases the amount of oxygen available for the muscles, thereby increasing performance. There is currently no clear evidence to suggest that this is the case in elite cyclists (Heuberger et al 2013)
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