Increased muscle blood supply and transendothelial nutrient and insulin transport induced by food intake and exercise: effect of obesity and ageing.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing mechanistic and physiological literature without systematic search methodology
PubMed 25627798 · doi:10.1113/jphysiol.2014.284513
What was done
This narrative review synthesizes literature on skeletal muscle microvascular regulation, microvascular unit recruitment, and transendothelial transport of glucose, fatty acids, and insulin in response to food intake, exercise, aging, and obesity.
What was found
The abstract reports no numerical data or effect sizes. It describes qualitatively that sedentary lifestyle, obesity, and aging reduce microvascular density and blunt vasodilator responses to insulin, exercise, and VEGF-A. Muscle contraction and insulin recruit microvascular units (terminal arterioles supplying up to 20 capillaries), expanding endothelial surface area for nutrient and insulin transport. Skeletal muscle VEGF-B expression regulates endothelial fatty acid transporter expression.
Why it matters
It highlights microvascular recruitment as a pivotal bottleneck in muscle nutrient delivery, linking microvascular impairment directly to metabolic diseases and insulin resistance.
Limits
As a narrative review, it lacks systematic search criteria, risk-of-bias assessment, and meta-analytic synthesis. The abstract provides purely qualitative mechanistic summaries without sample sizes or quantitative clinical endpoints.
Cited by
- supports Aging impairs insulin-mediated capillary recruitment and vasodilation in skeletal muscle without necessarily causing overt glycemic insulin resistance.