Reduced skeletal muscle capillarization and glucose intolerance

Abstract

Objective: Reduced capillarization in hemiparetic skeletal muscle of chronic stroke patients can limit insulin, glucose, and oxygen supply to muscle, thereby contributing to impaired glucose metabolism and cardiovascular deconditioning. We hypothesized that compared to sedentary controls, stroke subjects have reduced skeletal muscle capillarization that is associated with glucose intolerance and reduced peak oxygen consumption (Vo(2peak)).

Methods: Twelve chronic stroke subjects (ages, 62.1+/-2.8 years), and matched sedentary controls with impaired (n=12) or normal (n=12) glucose tolerance underwent oral glucose tolerance tests, exercise tests, and vastus lateralis biopsies.

Results: Stroke subjects had lower capillarization in hemiparetic muscle than in nonparetic muscle and normal glucose tolerant controls ( approximately 22 and approximately 28%, respectively; P<0.05) and had similar bilateral capillarization, compared to controls with impaired glucose tolerance. Capillary density in hemiparetic muscle inversely correlated with 120-minute glucose (r=-0.70, P<0.01) and glucose area under the curve (r=-0.78, P<0.01). Vo(2peak) was approximately 40% lower in stroke subjects, compared to controls (P<0.001), but did not correlate with capillarization (P=n.s.).

Conclusions: Hemiparetic muscle capillarization is reduced after stroke, and reduced capillarization is associated with glucose intolerance in stroke and control subjects. Interventions to increase skeletal muscle capillarization may prove beneficial for improving glucose metabolism in chronic stroke patients.

Figures

Figure 1

Capillary density (CD) in chronic stroke subjects and controls. Data are presented as mean ± SEM. *Significant difference, compared to control subjects with normal glucose tolerance (NGT), P <0.01.

Figure 2

Scatterplots depicting the correlations between (A) capillary-fiber perimeter exchange index (CFPE) in overall muscle and 120-minute glucose and (B) capillary density (CD) in type I muscle fibers and glucose area under the curve (GAUC) in all subjects. Capillarization measurements in chronic stroke subjects represent the average of hemiparetic and nonparetic muscle.