Lower skeletal muscle capillarization in hypertensive elderly men

Marine Gueugneau (1) , Cécile Coudy-Gandilhon (1) , Bruno Meunier (2) , Lydie Combaret (1) , Daniel Taillandier (1) , Cécile Polge (1) , Didier Attaix (1) , Frédéric Roche (3) , Léonard Feasson (4, 5, 6, 7) , Jean-Claude Barthélémy (3) , Daniel Bechet (1)

1 UNH - Unité de Nutrition Humaine
2 UMRH - Unité Mixte de Recherche sur les Herbivores - UMR 1213
3 Service de Physiologie Clinique et de l'Exercice [CHU de Saint-Etienne]
4 Centre de Référence des Maladies Neuromusculaires Rares, Unité de Myologie
5 LPE - Laboratoire de Physiologie de l'Exercice
6 Institut de recherche Expérimentale et Clinique-Pôle d'Endocrinologie, Diabétologie, et Nutrition (EDIN)
7 LIBM - Laboratoire Interuniversitaire de Biologie de la Motricité

Aging strongly affects the skeletal muscle and is associated with microvascular dysfunctions. Age is also a primary risk factor for the metabolic syndrome, which is a cluster of metabolic and cardiovascular symptoms. Among the metabolic syndrome components, hypertension is the most prevalent in elderly subjects and has a central role in vascular alterations. Despite critical clinical outcomes, the effects of hypertension and metabolic syndrome on skeletal muscle capillarization have poorly been investigated during aging. In the present study, muscle biopsies from normotensive young (YO) and elderly (ELc) men, and elderly men with hypertension (EL-HT) or metabolic syndrome (EL-MS) were assessed for the number of capillaries around a fiber (CAF), capillary-to-fiber perimeter exchange (CFPE), length of contact to perimeter of fiber ratio (LC/PF), capillary tortuosity, and for extracellular matrix (ECM) embedding capillaries. As capillarization and muscle mitochondrial oxidative capacity may be associated, we also investigated cytochrome c oxidase (COX) content. Our findings indicate that capillarization and COX did not change between normotensive adult and old individuals. They further reveal that hypertension in elderly men is associated with reduced CAF (ELc: 5.2 +/- 0.4, EL-HT: 4.1 +/- 0.2, P < 0.02 for type I fibers; ELc: 4.1 +/- 0.2, EL-HT: 3.1 +/- 0.3, P < 0.03 for type IIA fibers), CFPE (ELc: 7.9 +/- 0.7, EL-HT: 6.4 +/- 0.4 capillaries/1000 mu m, P < 0.03 for type I fibers; ELc: 6.5 +/- 0.4, EL-HT: 5.2 +/- 0.4 capillaries/1000 mu m, P < 0.03 for type IIA fibers), LC/PF (ELc: 23.3 +/- 1.2, EL-HT: 17.8 +/- 0.6%, P < 0.01 for type I fibers; ELc: 19.8 +/- 1.1, EL-HT: 15.6 +/- 0.8%, P < 0.01 for type IIA fibers) and capillary tortuosity, and with ECM endomysium fibrosis. Capillary rarefaction also correlated with lower COX content in the old hypertensive muscle. No further modification occurred with metabolic syndrome in elderly men. Collectively, our results suggest that hypertension plays a central role in muscle capillarization during aging, and that the other components of metabolic syndrome do not make major additional changes in the aged skeletal muscle capillary network

Mots clés: hypertension; capillary; aging; metabolic syndrome; muscle fiber; sarcopenia

Domaines: Gériatrie et gérontologie; Alimentation et Nutrition

Marine Gueugneau, Cécile Coudy-Gandilhon, Bruno Meunier, Lydie Combaret, Daniel Taillandier, et al.. Lower skeletal muscle capillarization in hypertensive elderly men. Experimental Gerontology, 2016, 76, pp.80-88. ⟨10.1016/j.exger.2016.01.013⟩. ⟨hal-01297805⟩