News

2016.11.28 Press Release

A stabilized hypoxic response favors the effect of endurance training

The research group led by Professor Ryoichi Nagatomi, Division of Biomedical Engineering for Health and Sports and Exercise, Graduate School of Biomedical Engineering, Tohoku University has reported that stabilized hypoxic response favors the effect of endurance training through skeletal muscle adaptation in a model mouse experiment.

Hypoxic response seems to contribute to the benefit of endurance training, which is known as hypoxic training (or altitude training). Putative increase in the capacity of oxygen supply by increased hemoglobin concentration and increased capillary density has been accepted as a possible underlying mechanism. However, controversial results have been indicated through human studies. To verify the veracity of the benefit of hypoxic training, the researchers examined the effect of 4-week running training on maximal endurance capacity of model genetically manipulated mice presenting hypoxic response.

Under normal oxygen concentration, an intracellular enzyme called prolyl hydroxylase domain 2 (PHD2) triggers disposal of hypoxia inducible factor (HIF-1). Under low oxygen concentration, inactivation of PHD2 leads to intracellular accumulation of HIF-1 which triggers a series of hypoxic response. Thus, the research group generated mice lacking PHD2(Phd2-deficient mice) which exhibit hypoxic response without exposing them to low oxygen concentration, which is a great advantage to the investigators.

They found a marked improvement in the exercise capacity of PHD2 deficient mice. The increase in the running time after training was longer in PHD2 deficient mice by a factor of 1.57 compared with the control mice. Interestingly, despite marked increase in the hemoglobin concentration (21.6g/dL-1) which may benefit oxygen delivery, the endurance capacity of PHD2 deficient mice did not improve without training. Skeletal muscle adaptation induced by training was required for the enhanced training effect in PHD2-deficient mice. The investigators suggested that hematological alteration is not sufficient for improved exercise capacity, but hypoxic adaptation in PHD2-deficiency favored skeletal muscle adaptation by running training in gaining enhanced endurance capacity.
This research was originally published in Acta Physiologica ©, an official journal of the Federation of European Physiological Societies (FEPS).

Contact
(About the research)
Professor Roichi NAGATOMI
Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine
Division of Biomedical Engineering for Health and Sports and Exercise, Tohoku University Graduate School of Biomedical Engineering
TEL: +81-22-717-7294
E-mail: nagatomi*med.tohoku.ac.jp (Replace * with @)

(Public Relations)
Lecturer Hitoshi Inada
Public Relations Office of Tohoku University Graduate School of Medicine
TEL: +81-22-717-7891 FAX: +81-22-717-8187
E-mail: pr-office*med.tohoku.ac.jp (Replace * with @)