Inflammatory Gene Expression in Neck Perivascular and Subcutaneous Adipose Tissue in Men With Carotid Stenosis

Neck circumference predicts development of carotid intima-media thickness and carotid plaque: A community-based longitudinal study

BACKGROUND AND AIMS

Carotid intima-media thickness (C-IMT) is an important index for evaluating subclinical atherosclerosis. Neck circumference (NC), a new anthropometric index of the upper body fat, is closely related to cardiovascular disease (CVD) and CVD risk factors. This study investigated the relationship between NC, C-IMT, and carotid plaque in a community-based cohort.

METHODS AND RESULTS

Participants recruited from Shanghai communities were followed up for 1.1-2.9 years. All participants underwent anthropometric and biochemical measurements. Elevated NC was defined as NC ≥ 38.5 cm and NC ≥ 34.5 cm in men and women, respectively. Elevated C-IMT, determined by ultrasound, was defined as a level higher than the 75th percentile in the study population (>0.75 mm). In total, 1189 participants without carotid plaque at baseline were included, with an average age of 59.6 ± 7.3 years. After a mean follow-up of 2.1 ± 0.2 years, 203 participants developed carotid plaques. After adjusting for various atherosclerosis risk factors, the logistic regression showed that the higher NC group had a significantly greater risk of developing carotid plaque than the lower NC group (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.12-2.14; P = 0.008). Of those without carotid plaque at follow-up, 495 participants developed elevated C-IMT. Compared to the lower NC group, the higher NC group had a significantly increased risk of elevated C-IMT (OR, 1.49; 95% CI, 1.14-1.95; P = 0.003).

CONCLUSION

Higher NC was significantly positively correlated with the risk of carotid plaque and elevated C-IMT.

Perivascular Adipose-Derived Exosomes Reduce Foam Cell Formation by Regulating Expression of Cholesterol Transporters

Background: Accumulating evidence demonstrates that perivascular adipose tissue (PVAT) plays an important role in maintaining vascular homeostasis. The formation of macrophage foam cells is a central feature of atherosclerosis. This study aimed to evaluate the effect of PVAT-derived exosomes (EXOs) on the lipid accumulation of macrophages and verify the anti-atherogenic characteristics of PVAT.

Methods and Results: We extracted EXOs from the PVAT and subcutaneous adipose tissue (SCAT) of wild-type C57BL/6J mice. After coincubation, the EXOs were taken up by RAW264.7 cells. Oil Red O staining revealed that macrophage foam cell formation and intracellular lipid accumulation were ameliorated by PVAT-EXOs. Flow cytometry showed that PVAT-EXOs significantly reduced macrophage uptake of fluorescence-labelled oxidised low-density lipoprotein (ox-LDL). In addition, high-density lipoprotein-induced cholesterol efflux was promoted by PVAT-EXOs. Western blot analysis showed the downregulation of macrophage scavenger receptor A and the upregulation of ATP-binding cassette transporter A1 and ATP-binding cassette transporter G1, which could be mediated by the overexpression of peroxisome proliferator-activated receptor γ and was independent of liver X receptor α.

Conclusion: Our findings suggest that PVAT-EXOs reduce macrophage foam cell formation by regulating the expression of cholesterol transport proteins, which provides a novel mechanism by which PVAT protects the vasculature from atherosclerosis.