Insulin resistance is associated with lower acetylcholine-induced microvascular reactivity in nondiabetic women

Pienaar, P. R., Micklesfield, L. K., Levitt, N. S., Gooding, K., Shore, A. C., Goedecke, J. H., Gill, J. M.R. and Lambert, E. V. (2014) Insulin resistance is associated with lower acetylcholine-induced microvascular reactivity in nondiabetic women. Metabolic Syndrome and Related Disorders, 12(3), pp. 178-184. (doi: 10.1089/met.2013.0126)

Abstract

Background: The association between insulin resistance and microvascular dysfunction is well established in obese individuals with type 2 diabetes. It is unclear whether this relationship is dependent on obesity and body fat in insulin-resistant persons. This study investigated acetylcholine (ACh)-induced microvascular reactivity in apparently healthy women (n=37, 20–45 years), with and without insulin resistance.<p></p> Methods: Body fat mass (dual X-ray absorptiometry), waist circumference (WC), blood pressure, fasting glucose, insulin, and free fatty acid concentrations were measured. Insulin resistance was estimated using homeostasis model assessment of insulin resistance (HOMA-IR), and subjects were divided into insulin-resistant (IR, n=16) and insulin-sensitive (IS, n=21) groups. ACh-induced forearm microvascular reactivity was measured by laser Doppler imagery using iontophoresis of ACh and compared between groups adjusting for WC and skin resistance (SR).<p></p> Results: The IR group had a higher body mass index (BMI) (30.7±6.4 vs. 22.9±7.3 kg/m2, P<0.01), fat mass (34.7±11.9 vs. 19.7±9.6 kg, P<0.01), WC (89.9±13.6 vs. 74.4±9.7 cm, P<0.01), and a lower SR (0.24±0.08 vs. 0.32±0.08 Ω, P<0.05) than the IS group. Microvascular reactivity, expressed as percentage increase in perfusion from baseline, was significantly lower in IR subjects after adjusting for differences in WC and SR (420.9±166.5 vs. 511.6±214.8%, P<0.05). There were associations between microvascular reactivity and SR (r=−0.34, P<0.05) and systolic blood pressure (r=−0.36, P<0.05), but not BMI, body fat mass, WC, or HOMA-IR.<p></p> Conclusion: ACh-induced microvascular reactivity was different between IR and IS apparently healthy, nondiabetic women once differences in WC and SR were accounted for.<p></p>

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Gill, Professor Jason
• Authors: Pienaar, P. R., Micklesfield, L. K., Levitt, N. S., Gooding, K., Shore, A. C., Goedecke, J. H., Gill, J. M.R., and Lambert, E. V.
• College/School: College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Journal Name: Metabolic Syndrome and Related Disorders
• Publisher: Mary Ann Liebert
• ISSN: 1540-4196
• ISSN (Online): 1557-8518