title: Erythropoietin administration alone or in combination with endurance training affects neither skeletal muscle morphology nor angiogenesis in healthy young men.
abstract: The aim was to investigate the ability of an erythropoiesis-stimulating agent (ESA), alone or in combination with endurance training, to induce changes in human skeletal muscle fibre and vascular morphology. In a comparative study, 36 healthy untrained men were randomly dispersed into the following four groups: sedentary-placebo (SP, n = 9); sedentary-ESA (SE, n = 9); training-placebo (TP, n = 10); or training-ESA (TE, n = 8). The ESA or placebo was injected once weekly. Training consisted of progressive bicycling three times per week for 10 weeks. Before and after the intervention period, muscle biopsies and magnetic resonance images were collected from the thigh muscles, blood was collected, body composition measured and endurance exercise performance evaluated. The ESA treatment (SE and TE) led to elevated haematocrit, and both ESA treatment and training (SE, TP and TE) increased maximal O2 uptake. With regard to skeletal muscle morphology, TP alone exhibited increases in whole-muscle cross-sectional area and fibre diameter of all fibre types. Also exclusively for TP was an increase in type IIa fibres and a corresponding decrease in type IIx fibres. Furthermore, an overall training effect (TP and TE) was statistically demonstrated in whole-muscle cross-sectional area, muscle fibre diameter and type IIa and type IIx fibre distribution. With regard to muscle vascular morphology, TP and TE both promoted a rise in capillary to muscle fibre ratio, with no differences between the two groups. There were no effects of ESA treatment on any of the muscle morphological parameters. Despite the haematopoietic effects of ESA, we provide novel evidence that endurance training rather than ESA treatment induces adaptational changes in angiogenesis and muscle morphology.
authors.affiliation: Section of Sports Science, Institute of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Mads S
authors.initials: MS
authors.lastname: Larsen
authors.affiliation: Section of Sports Science, Institute of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Kristian
authors.initials: K
authors.lastname: Vissing
authors.affiliation: Section of Sports Science, Institute of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Line
authors.initials: L
authors.lastname: Thams
authors.affiliation: Section of Sports Science, Institute of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Sieljacks
authors.affiliation: Section of Sports Science, Institute of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Ulrik
authors.initials: U
authors.lastname: Dalgas
authors.affiliation: Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Birgitte
authors.initials: B
authors.lastname: Nellemann
authors.affiliation: Section of Sports Science, Institute of Public Health, Aarhus University, Aarhus, Denmark Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark britt.christensen@ki.au.dk.
authors.forename: Britt
authors.initials: B
authors.lastname: Christensen
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology; D000293:Adolescent; D000328:Adult; D001642:Bicycling / Q000502:physiology; D001823:Body Composition / Q000187:drug effects / Q000502:physiology; D004921:Erythropoietin / Q000494:pharmacology*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000502:physiology; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D055815:Young Adult
chemical_list: D004921:Erythropoietin