Clinical Research
Cardiometabolic Risk
Effects of Bariatric Surgery on Human Small Artery Function: Evidence for Reduction in Perivascular Adipocyte Inflammation, and the Restoration of Normal Anticontractile Activity Despite Persistent Obesity

https://doi.org/10.1016/j.jacc.2013.04.027Get rights and content
Under a Creative Commons license
open access

Objectives

The aim of this study was to investigate the effects of bariatric surgery on small artery function and the mechanisms underlying this.

Background

In lean healthy humans, perivascular adipose tissue (PVAT) exerts an anticontractile effect on adjacent small arteries, but this is lost in obesity-associated conditions such as the metabolic syndrome and type II diabetes where there is evidence of adipocyte inflammation and increased oxidative stress.

Methods

Segments of small subcutaneous artery and perivascular fat were harvested from severely obese individuals before (n = 20) and 6 months after bariatric surgery (n = 15). Small artery contractile function was examined in vitro with wire myography, and perivascular adipose tissue (PVAT) morphology was assessed with immunohistochemistry.

Results

The anticontractile activity of PVAT was lost in obese patients before surgery when compared with healthy volunteers and was restored 6 months after bariatric surgery. In vitro protocols with superoxide dismutase and catalase rescued PVAT anticontractile function in tissue from obese individuals before surgery. The improvement in anticontractile function after surgery was accompanied by improvements in insulin sensitivity, serum glycemic indexes, inflammatory cytokines, adipokine profile, and systolic blood pressure together with increased PVAT adiponectin and nitric oxide bioavailability and reduced macrophage infiltration and inflammation. These changes were observed despite the patients remaining severely obese.

Conclusions

Bariatric surgery and its attendant improvements in weight, blood pressure, inflammation, and metabolism collectively reverse the obesity-induced alteration to PVAT anticontractile function. This reversal is attributable to reductions in local adipose inflammation and oxidative stress with improved adiponectin and nitric oxide bioavailability.

Key Words

bariatric
cardiovascular
obesity

Abbreviations and Acronyms

AdipoR1
adiponectin receptor 1
BMI
body mass index
hsCRP
high-sensitivity C-reactive protein
NO
nitric oxide
PVAT
perivascular adipose tissue
TNF
tumor necrosis factor

Cited by (0)

This study was funded by 2 Clinical Research Fellowships awarded to Dr. Aghamohammadzadeh (British Heart Foundation [FS/10/42/ 28372] and NIHR Manchester Biomedical Research Centre); and the support of Wellcome Trust Clinical Research Facility (Manchester, United Kingdom). Dr. Greenstein was funded by the British Heart Foundation (FS11/68/28821). Drs. Greenstein and Heagerty were funded by the British Heart Foundation (FS12/81/29882). All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.