Increased visceral fat accumulation modifies the effect of insulin resistance on arterial stiffness and hypertension risk

Background and aims: Both insulin resistance (IR) and visceral adipose tissue (VAT) are related cardiometabolic risk factors; nevertheless, their joint effect on endothelial functionality is controversial. This study aims to evaluate the joint effect of IR and VAT on endothelial functionality using the pulse-waveform analysis and explore the mediating role of VAT on the effect of IR on arterial pressure, arterial stiffness and incident arterial hypertension. Methods and results: We measured VAT (n = 586) using two methods (dual-energy X-ray absorptiometry and a clinical surrogate), arterial stiffness (with pulse-waveform velocity), and IR (using three methods: HOMA2-IR (n = 586), a frequently sampled intravenous glucose tolerance test (n = 131) and euglycemic hyperinsulinemic clamping (n = 97)) to confirm the mediator effect of IR on VAT. The incidence of arterial hypertension attributable to the mediating effect of IR related to VAT was evaluated using a prospective cohort (n = 6850). Adjusted linear regression models, causal mediation analysis, and Cox-proportional hazard risk regression models were performed to test our objective. IR and VAT led to increased arterial stiffness and increased blood pressure; the combination of both further worsened vascular parameters. Nearly, 57% (Delta(E -> MY) 95% CI: 31.7-100.0) of the effect of IR on altered pulse-wave velocity (PWV) analysis was mediated through VAT. Moreover, VAT acts as a mediator of the effect of IR on increased mean arterial pressure (Delta(E -> MY) 35.7%, 95% CI: 23.8-59) and increased hypertension risk (Delta(E -> MY) 69.1%, 95% CI: 46.1-78.8). Conclusion: VAT acts as a mediator of IR in promoting arterial stiffness and arterial hypertension. Both phenomena should be targeted to ameliorate the cardiometabolic risk. (C) 2020 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

Automated summary

This study found that the joint effect of insulin resistance and visceral adipose tissue on endothelial functionality, arterial stiffness, and hypertension is controversial. Visceral adipose tissue acts as a mediator of insulin resistance in promoting arterial stiffness and arterial hypertension. Both insulin resistance and visceral adipose tissue should be targeted to ameliorate cardiometabolic risk.