TY - JOUR

T1 - No evidence for direct effects of recombinant human erythropoietin on cerebral blood flow and metabolism in healthy humans

AU - Vestergaard, Mark Bitsch

AU - Henriksen, Otto Mølby

AU - Lindberg, Ulrich

AU - Aachmann-Andersen, Niels Jacob

AU - Lisbjerg, Kristian

AU - Christensen, Søren Just

AU - Olsen, Niels Vidiendal

AU - Law, Ian

AU - Larsson, Henrik Bo Wiberg

AU - Rasmussen, Peter

PY - 2018

Y1 - 2018

N2 - Erythropoietin (EPO) is expressed in human brain tissue, but its exact role is unknown. EPO may improve the efficiency of oxidative metabolism and has neuroprotective properties against hypoxic injuries in animal models. We aimed to investigate the effect of recombinant human EPO (rHuEPO) administration on healthy cerebral metabolism in humans during normoxia and during metabolic stress by inhalation of 10% O2 hypoxic air. Twenty-four healthy men participated in a two-arm double-blind placebo-controlled trial. rHuEPO was administered as a low dose (5,000 IU) over 4 wk (n = 12) or as a high dose (500 IU·kg body wt-1·day-1) for three consecutive days (n = 12). Global cerebral blood flow (CBF) and metabolic rate of glucose (CMRglc) were measured with positron emission tomography. CBF, metabolic rate of oxygen (CMRO2 ), and cerebral lactate concentration were measured by magnetic resonance imaging and spectroscopy. Low-dose treatment increased hemoglobin and was associated with a near-significant decrease in CBF during baseline normoxia. High-dose treatment caused no change in CBF. Neither treatment had an effect on normoxia CMRglc, CMRO2 , or lactate concentration or an effect on the cerebral metabolic response to inhalation of hypoxic air. In conclusion, the study found no evidence for a direct effect of rHuEPO on cerebral metabolism. NEW & NOTEWORTHY We demonstrate with magnetic resonance imaging and positron emission tomography that administration of erythropoietin does not have a substantial direct effect on healthy human resting cerebral blood flow or effect on cerebral glucose and oxygen metabolism. Also, administration of erythropoietin did not have a direct effect on the metabolic response to acute hypoxic stress in healthy humans, and a suggested neuroprotective effect from erythropoietin is therefore likely not a direct effect of erythropoietin on cerebral metabolism.

AB - Erythropoietin (EPO) is expressed in human brain tissue, but its exact role is unknown. EPO may improve the efficiency of oxidative metabolism and has neuroprotective properties against hypoxic injuries in animal models. We aimed to investigate the effect of recombinant human EPO (rHuEPO) administration on healthy cerebral metabolism in humans during normoxia and during metabolic stress by inhalation of 10% O2 hypoxic air. Twenty-four healthy men participated in a two-arm double-blind placebo-controlled trial. rHuEPO was administered as a low dose (5,000 IU) over 4 wk (n = 12) or as a high dose (500 IU·kg body wt-1·day-1) for three consecutive days (n = 12). Global cerebral blood flow (CBF) and metabolic rate of glucose (CMRglc) were measured with positron emission tomography. CBF, metabolic rate of oxygen (CMRO2 ), and cerebral lactate concentration were measured by magnetic resonance imaging and spectroscopy. Low-dose treatment increased hemoglobin and was associated with a near-significant decrease in CBF during baseline normoxia. High-dose treatment caused no change in CBF. Neither treatment had an effect on normoxia CMRglc, CMRO2 , or lactate concentration or an effect on the cerebral metabolic response to inhalation of hypoxic air. In conclusion, the study found no evidence for a direct effect of rHuEPO on cerebral metabolism. NEW & NOTEWORTHY We demonstrate with magnetic resonance imaging and positron emission tomography that administration of erythropoietin does not have a substantial direct effect on healthy human resting cerebral blood flow or effect on cerebral glucose and oxygen metabolism. Also, administration of erythropoietin did not have a direct effect on the metabolic response to acute hypoxic stress in healthy humans, and a suggested neuroprotective effect from erythropoietin is therefore likely not a direct effect of erythropoietin on cerebral metabolism.

KW - Cerebral blood flow

KW - Cerebral lactate

KW - Cerebral metabolic rate of glucose

KW - Cerebral metabolic rate of oxygen

KW - Erythropoietin

U2 - 10.1152/japplphysiol.00869.2017

DO - 10.1152/japplphysiol.00869.2017

M3 - Journal article

C2 - 29357480

AN - SCOPUS:85047772608

VL - 124

SP - 1107

EP - 1116

JO - Journal of Applied Physiology

JF - Journal of Applied Physiology

SN - 8750-7587

IS - 4

ER -