Title:Modulation of Small Artery Function by Insulin in Young Women: Role of Adiposity
Volume: 20
Issue: 8
Author(s): Moulinath Banerjee*, Linda Shaw, Valentyn Charlton-Menys, Phillip Pemberton, Rayaz Ahmed Malik, John Kennedy Cruickshank and Clare Elizabeth Austin
Affiliation:
- Centre for Endocrinology & Diabetes Research Group, University of Manchester, Manchester M13 9NT,United Kingdom
Keywords:
Small artery function, endothelium, insulin, adiposity, women, myography.
Abstract:
Objectives: Vascular dysfunction is common in obesity. Insulin can directly modulate arterial
function, but its role is unclear in obesity. We examined the influence of adiposity on direct effects
of insulin on human artery responses.
Methods: 22 healthy women were stratified by median BMI into lower (LA) (n=11) and higher adiposity
(HA) (n=11). Small arteries from gluteal biopsies were tested for contractile responses to
Noradrenaline (NA), the endothelium-dependent dilator Carbachol and the endothelium-independent
dilator sodium nitroprusside were examined before and after incubation with 100 mU/ml human insulin.
Results: Contractile responses were similar in the two groups. Insulin reduced NA-induced contraction
in HA [3.5 (2.4-4.6) vs. 2.4 (1.4-3.4) mN/mm: p=0.004] but not those from LA [4.1 (2.8-5.3) vs. 3.7
(2.5-5.0) mN/mm: p=0.33]. Endothelium-dependent dilation (EDD) was significantly reduced in arteries
from women in the HA (34.7 (18.8-50.6%)) compared to those from women in the LA (62.3 (46.2-
78.4); p=0.013). Insulin improved EDD (change in maximal dilation before/after insulin (%)) in arteries
from the HA (37.7 (18.0 to 57.3) but not the LA (6.3 (-6.5 to 19.1), p=0.007.
Conclusion: Reduced EDD evident in arteries from HA subjects improve by incubating in insulin.
Hyperinsulinaemia may be necessary in maintaining endothelial function in obesity.
