Postmaximal contraction blood volume responses are blunted in obese and type 2 diabetic subjects in a muscle-specific manner.

Sanchez OA, Copenhaver EA, Chance MA, Fowler MJ, Towse TF, Kent-Braun JA, Damon BM
Am J Physiol Heart Circ Physiol. 2011 301 (2): H418-27

PMID: 21572006 · PMCID: PMC3154659 · DOI:10.1152/ajpheart.00060.2011

The purpose of this study was to determine whether there are differences in postisometric contraction blood volume and oxygenation responses among groups of type 2 diabetes mellitus (T2DM), obese, and lean individuals detectable using MRI. Eight T2DM patients were individually matched by age, sex, and race to non-T2DM individuals with similar body mass index (obese) and lean subjects. Functional MRI was performed using a dual-gradient-recalled echo, echo-planar imaging sequence with a repetition time of 1 s and at two echo times (TE = 6 and 46 ms). Data were acquired before, during, and after 10-s isometric dorsiflexion contractions performed at 50 and 100% of maximal voluntary contraction (MVC) force. MRI signal intensity (SI) changes from the tibialis anterior and extensor digitorum longus muscles were plotted as functions of time for each TE. From each time course, the difference between the minimum and the maximum postcontraction SI (ΔSI) were determined for TE = 6 ms (ΔSI(6)) and TE = 46 ms (ΔSI(46)), reflecting variations in blood volume and oxyhemoglobin saturation, respectively. Following 50% MVC contractions, the mean postcontraction ΔSI(6) values were similar in the three groups. Following MVC only, and in the EDL muscle only, T2DM and obese participants had ∼56% lower ΔSI(6) than the lean individuals. Also following MVC only, the ΔSI(46) response in the EDL was lower in T2DM subjects than in lean individuals. These data suggest that skeletal muscle small vessel impairment occurs in T2DM and body mass index-matched subjects, in muscle-specific and contraction intensity-dependent manners.

MeSH Terms (18)

Adult Blood Volume Diabetes Mellitus, Type 2 Female Humans Isometric Contraction Linear Models Magnetic Resonance Imaging Male Microcirculation Middle Aged Muscle, Skeletal Obesity Oxygen Oxygen Consumption Oxyhemoglobins Regional Blood Flow Time Factors

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