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

Background: 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.Conclusions: The properties of SV-PVAT are close to, but not the same as, those of SCAT, possibly resulting from inherent differ-ences in adipocytes. SV-PVAT has healthy expansion with less fibrosis in fat than SCAT.