Individuals who undergo Roux-en-Y gastric bypass (RYGB) show improved high-density lipoprotein (HDL) functionality, which then contributes to a decrease in adipose tissue and systemic inflammation, reports a recent study.

In this analysis, the authors measured biomarkers associated with increased cardiovascular disease (CVD) risk, including tumour necrosis factor-α (TNF-α), high-sensitivity C-reactive protein (hsCRP), myeloperoxidase mass (MPO), PON1 activity, and CEC in vitro, in 44 patients before and 6 and 12 months after bariatric surgery.

Overweight, healthy individuals (mean body mass index [BMI], 28 kg/m2) served as controls. In addition, 12 participants submitted themselves to gluteal subcutaneous adipose tissue biopsies before and 6 months after RYGB for targeted gene expression (ABCA1, ABCG1, SR-B1, TNF-α) and histological analysis (adipocyte size, macrophage density, TNF-α immunostaining).

BMI, HDL-cholesterol, hsCRP, TNF-α, MPO mass, PON1 activity, and CEC in vitro significantly improved following RYGB (p<0.05). ABCG1 (fold-change, 2.24; p=0.005) and ABCA1 gene expression increased significantly (fold-change, 1.34; p=0.05).

RYGB also reduced gluteal fat adipocyte size (p<0.0001), macrophage density (p=0.0067), and TNF-α immunostaining (p=0.0425), while ABCG1 expression showed an inverse association with TNF-α immunostaining (r, ‒0.71; p=0.03).

“HDL is essential for reverse cholesterol transport (RCT) and reduces inflammation and oxidative stress principally via paraoxonase-1 (PON1),” the authors said.

“RCT depends on HDL’s capacity to accept cholesterol (cholesterol efflux capacity [CEC]) and active transport through ATP-binding cassette (ABC) A1, G1, and scavenger receptor-B1 (SR-B1),” they added.