Comparison of Phenotypes in Subcutaneous Fat and Perivascular Adipose Tissue Surrounding the Saphenous Vein in Coronary Artery Bypass Grafting.

Abstract

The saphenous vein (SV) is used as an essential conduit in coronary artery bypass grafting (CABG), but the long-term patency of SV grafts is a crucial issue. The use of the novel "no-touch" technique of harvesting the SV together with its surrounding tissue has been reported to result in good long-term graft patency of SV grafts. We recently showed that perivascular adipose tissue (PVAT) surrounding the SV (SV-PVAT) had lower levels of metaflammation and consecutive adipose tissue remodeling than did PVAT surrounding the coronary artery. However, the difference between SV-PVAT and subcutaneous adipose tissue (SCAT) remains unclear.Methods and Results: Fat pads were sampled from 55 patients (38 men, 17 women; mean [±SD] age 71±8 years) with coronary artery disease who underwent elective CABG. Adipocyte size was significantly larger in SV-PVAT than SCAT. The extent of fibrosis was smaller in SV-PVAT than SCAT. There were no significant differences between SCAT and SV-PVAT in macrophage infiltration area, quantified by antibodies for CD68, CD11c, and CD206, or in gene expression levels of metaflammation-related markers. Expression patterns of adipocyte developmental and pattern-forming genes differed between SCAT and SV-PVAT. The properties of SV-PVAT are close to, but not the same as, those of SCAT, possibly resulting from inherent differences in adipocytes. SV-PVAT has healthy expansion with less fibrosis in fat than SCAT.