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Effects of erythropoietin on systemic hematocrit and oxygen transport in the splenectomized horse.
Abstract: To test the hypotheses that erythropoietin (rhuEPO) treatment increases systemic hematocrit, maximal O2 uptake (VO2max, by elevated perfusive and diffusive O2 conductances) and performance five female horses (4-13 years) received 15 IU/kg rhuEPO (erythropoietin) three times per week for three weeks. These horses had been splenectomized over 1 year previously to avoid confounding effects from the mobilization of splenic red blood cell reserves. Each horse performed three maximal exercise tests (one per month) on an inclined (4°) treadmill to the limit of tolerance; two control trials and one following EPO treatment. Measurements of hemoglobin concentration ([Hb] and hematocrit), plasma and blood volume, VO2, cardiac output as well as arterial and mixed venous blood gases were made at rest and during maximal exercise. EPO increased resting [Hb] by 18% from 13.3 ± 0.6 to 15.7 ± 0.8 g/dL (mean ± SD) corresponding to an increased hematocrit from 36 ± 2 to 46 ± 2% concurrent with 23 and 10% reductions in plasma and blood volume, respectively (all P<0.05). EPO elevated VO2max by 20% from 25.7 ± 1.7 to 30.9 ± 3.4 L/min (P<0.05) via a 17% increase in arterial O2 content and 18% greater arteriovenous O2 difference in the face of an unchanged cardiac output. To achieve the greater VO2max after EPO, diffusive O2 conductance increased ∼ 30% (from 580 ± 76 to 752 ± 166 mL O2/mmHg/min, P<0.05) which was substantially greater than the elevation of perfusive O2 conductance. These effects of EPO were associated with an increased exercise performance (total running time: control, 216 ± 72; EPO, 264 ± 48 s, P<0.05). We conclude that EPO substantially increases VO2max and performance in the splenectomized horse via improved perfusive and diffusive O2 transport.
Copyright © 2016 Elsevier B.V. All rights reserved.
Publication Date: 2016-02-04 PubMed ID: 26853328DOI: 10.1016/j.resp.2016.02.001Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research was carried out to investigate the effects of erythropoietin, a hormone that stimulates the production of red blood cells, on the level of hematocrit, oxygen transport, and performance in horses that have had their spleens removed. The findings revealed that erythropoietin increases hematocrit, oxygen uptake during maximal exercise, and overall performance.
Introduction and Methodology
- The researchers hypothesized that treatment with recombinant human erythropoietin (rhuEPO) would increase systemic hematocrit (the proportion of blood that is made up of red blood cells), maximal oxygen uptake (VO2max), and total running time in horses.
- Five female horses, aged between 4 and 13 years, were subjected to a regime of receiving 15 IU/kg of rhuEPO three times weekly for three weeks.
- The horses had been splenectomized over a year prior to the study so as to eliminate any interference from the mobilization of red blood cells from the spleen.
- Throughout the course of the study, each horse performed three maximal exercise tests on an inclined treadmill to the limit of their tolerance. These tests took place once a month and included two control trials and one post-EPO treatment trial.
- Various measurements, including hemoglobin concentration, hematocrit, plasma and blood volume, cardiac output, and blood gases, were collected both at rest and during maximal exercise.
Key Findings
- EPO treatment led to an 18% increase in hemoglobin concentration and a corresponding increase in hematocrit from 36% to 46%.
- Concurrently, plasma and blood volume saw declines of 23% and 10% respectively.
- Maximal oxygen uptake increased by 20%, attributed to a 17% increase in arterial oxygen content and an 18% higher arteriovenous oxygen difference, even though the cardiac output remained the same.
- Diffusive oxygen conductance increased by about 30%, which was significantly more than the increase in perfusive oxygen conductance.
- The overall running time of the horses increased, indicating improved performance with EPO treatment.
Conclusion
- The study suggests that erythropoietin significantly improves performance in splenectomized horses by enhancing both perfusive and diffusive oxygen transport, thereby increasing the maximum oxygen uptake during exercise.
- It also significantly increases the proportion of red blood cells in the blood volume (hematocrit).
Cite This Article
APA
McKeever KH, McNally BA, Hinchcliff KW, Lehnhard RA, Poole DC.
(2016).
Effects of erythropoietin on systemic hematocrit and oxygen transport in the splenectomized horse.
Respir Physiol Neurobiol, 225, 38-47.
https://doi.org/10.1016/j.resp.2016.02.001 Publication
Researcher Affiliations
- Department of Animal Science, Rutgers the State University of New Jersey, New Brunswick, NJ 08903, United States. Electronic address: mckeever@aesop.rutgers.edu.
- School of Health, Physical Education and Recreation, The Ohio State University, Columbus, OH 43210, United States.
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Melbourne, Australia.
- Department of Kinesiology, University of Maine, Orono, ME, United States.
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, United States.
MeSH Terms
- Animals
- Blood Gas Analysis
- Blood Viscosity / physiology
- Erythropoietin / metabolism
- Exercise Test
- Female
- Hematocrit
- Hemodynamics
- Hemoglobins / metabolism
- Horses
- Movement / physiology
- Oxygen / metabolism
- Splenectomy
Citations
This article has been cited 4 times.- Dahlgren AR, Knych HK, Arthur RM, Durbin-Johnson BP, Finno CJ. Transcriptomic Markers of Recombinant Human Erythropoietin Micro-Dosing in Thoroughbred Horses. Genes (Basel) 2021 Nov 24;12(12).
- Bollinger L, Bartel A, Küper A, Weber C, Gehlen H. Age and Hydration of Competing Horses Influence the Outcome of Elite 160 km Endurance Rides. Front Vet Sci 2021;8:668650.
- Kämpf S, Seiler E, Bujok J, Hofmann-Lehmann R, Riond B, Makhro A, Bogdanova A. Aging Markers in Equine Red Blood Cells. Front Physiol 2019;10:893.
- Loria F, Grabherr S, Kuuranne T, Leuenberger N. Use of RNA biomarkers in the antidoping field. Bioanalysis 2024;16(10):475-484.
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