Fiche publication
Date publication
avril 2014
Auteurs
Membres identifiés du Cancéropôle Est :
Dr METZGER Daniel
Tous les auteurs :
Delavar H, Nogueira L, Wagner PD, Hogan MC, Metzger D, Breen EC
Lien Pubmed
Résumé
Vascular endothelial growth factor (VEGF) is exercise responsive, pro-angiogenic, and expressed in several muscle cell types. We hypothesized that in adult mice, VEGF generated within skeletal myofibers (and not other cells within muscle) is necessary for the angiogenic response to exercise training. This was tested in adult conditional, skeletal myofiber-specific VEGF gene-deleted mice (skmVEGF-/-), with VEGF levels reduced by >80%. After 8 wk of daily treadmill training, speed and endurance were unaltered in skmVEGF-/- mice, but increased by 18% and 99% (P < 0.01), respectively, in controls trained at identical absolute speed, incline, and duration. In vitro, isolated soleus and extensor digitorum longus contractile function was not impaired in skmVEGF-/- mice. However, training-induced angiogenesis was inhibited in plantaris (wild type, 38%, skmVEGF-/- 18%, P < 0.01), and gastrocnemius (wild type, 43%, P < 0.01; skmVEGF-/-, 7%, not significant). Capillarity was maintained (different from VEGF gene deletion targeted to multiple cell types) in untrained skmVEGF-/- mice. Arteriogenesis (smooth muscle actin+, artery number, and diameter) and remodeling [vimentin+, 5'-bromodeoxycytidine (BrdU)+, and F4/80+ cells] occurred in skmVEGF-/- mice, even in the absence of training. skmVEGF-/- mice also displayed a limited oxidative enzyme [citrate synthase and beta-hydroxyacyl CoA dehydrogenase (beta-HAD)] training response; beta-HAD activity levels were elevated in the untrained state. These data suggest that myofiber expressed VEGF is necessary for training responses in capillarity and oxidative capacity and for improved running speed and endurance.
Référence
Am J Physiol Regul Integr Comp Physiol. 2014 Apr 15;306(8):R586-95
