Insulin vascular action in skeletal muscle is attenuated with insulin resistance and features of metabolic syndrome

Turzyniecka, M.J., Ung, J.C.C., Krentz, A.J., Clough, G.F. and Byrne, C.D. (2007) Insulin vascular action in skeletal muscle is attenuated with insulin resistance and features of metabolic syndrome. Diabetologia, 50 (Supplement 1), S291.

Abstract

Background and Aims: the relationship between total muscle blood flow,
capillary recruitment and skeletal muscle insulin sensitivity remains unclear.
The aim of this study was to investigate insulin-induced changes in muscle
microvascular blood flow using a novel non-invasive laser Doppler surface
probe in individuals with features of metabolic syndrome

Materials and Methods: twenty one volunteers (age range 37 – 67years;
mean 51.5 ± 1.5y; 8 men) were recruited. All gave written informed consent.
Blood flux in muscle and skin was measured by laser Doppler fluximetry
(DRT4 Moor Instruments Ltd, UK) using a 785 nm, 20 mW, 4 mm separation
(muscle) and a 1 mW, 0.5 mm separation (skin) probe placed above the
anterior tibialis muscle. Measurements were made at rest and during a
reactive hyperaemia (RH) to arterial occlusion, before and during stepped
hyperinsulinaemic euglycaemic clamp at low (0.2 mU/kg/min) and high
dose insulin (1.5 mU/kg/ min). Insulin sensitivity was measured as the rate of
glucose disposal (M = mg/kg/min) during the steady state of the clamp.

Results: resting blood flux in muscle and skin was 80±3 and 9±0.3 AU
(arbitrary perfusion units), respectively. The insulin-induced increase in
resting muscle blood flow was positively related to insulin sensitivity (r=0.45
p<0.05). The relative increase in RH from baseline was negatively correlated
with percentage body fat measured by DEXA (r=–0.59, p< 0.02).

Conclusion: we conclude that insulin’s vascular action within skeletal muscle,
as measured by non- invasive laser Doppler fluximetry, is attenuated with
insulin resistance and with increased body fat. We speculate that an impaired
insulin response within skeletal muscle microvasculature may contribute to
whole body insulin resistance and to decreased glucose disposal by muscle
in these patients

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Contributors

Author: G.F. Clough

Author: C.D. Byrne

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