Human adipocytes from the subcutaneous superficial layer have greater adipogenic potential and lower PPAR-γ DNA methylation levels than deep layer adipocytes.

Human subcutaneous fat tissue consists of two layers, superficial adipose tissue (SAT) and deep adipose tissue (DAT). Some recent reports suggest that a disproportionate accumulation of DAT is related to obesity-associated metabolic complications. However, the differences in adipocyte function between SAT and DAT are unclear. To clarify the differences in human adipocyte characteristics between SAT and DAT, human ceiling culture-derived proliferative adipocytes (ccdPAs) were primary cultured from SAT and DAT of three lean female patients. Differences in adipogenic differentiation potential and sensitivity to exogenous adipogenic factors were examined. Epigenetic modification of the CpG island DNA methylation levels of genes related to adipogenesis was measured. In histological analyses, the mean adipocyte size in SAT was significantly larger than that in DAT (8,741 ± 416 vs. 7,732 ± 213 µm(2), P < 0.05). Primary cultured adipocytes from SAT showed significantly greater adipogenesis than did those of DAT. Sensitivity to partial adipogenic stimulation was significantly different between ccdPAs of SAT and DAT. Peroxisome proliferator-activated receptor-γ (PPAR-γ) protein expression and leptin protein secretion from ccdPAs were significantly higher in SAT than DAT. DNA methylation levels of PPAR-γ were significantly lower in ccdPAs of SAT than DAT. Adipocyte size was larger in SAT than DAT in vivo. This is consistent with the findings of an in vitro study that, compared with ccdPAs in DAT, ccdPAs in SAT have higher adipogenic potential and lower DNA methylation levels of PPAR-γ.

Low-rise scar deep inferior epigastric artery perforator flap for breast reconstruction.

BACKGROUND: To achieve an unnoticeable postoperative scar in patients with little abdominal skin laxity for breast reconstruction by deep inferior epigastric artery perforator (DIEP) flap, we devised a new design called the low-rise scar DIEP flap; the skin paddle of this flap is located lower with a smaller vertical width, and more adipose tissue is elevated to obtain enough volume. The purpose of this report is to evaluate the utility of the low-rise scar DIEP flap compared with that of the conventionally designed flap. METHODS: Twelve patients who underwent low-rise scar DIEP flaps (study group) and 11 patients who underwent conventionally-designed DIEP flaps (control group) were included in the present study. The distance from the umbilicus to horizontal scar was divided by the patient's height. The length of the scar was divided by the abdominal circumference. These ratios were compared between groups. RESULTS: All flaps survived completely and no recipient site complication was observed, except for one case in the control group with small-range fat necrosis. No donor site complication was observed in either group. The distance ratio was significantly larger in study group (<0.01, 0.049 ± 0.004, and 0.028 ± 0.005, respectively). The length ratio was significantly smaller in the study group <0.01, 0.42 ± 0.02 and 0.36 ± 0.02, respectively). The weight of the flap used for reconstruction was 338.8 ± 127.7 g in the study group and 320.5 ± 63.0 g in the control group CONCLUSIONS: A low-rise scar DIEP flap leaves a lower and shorter postoperative scar.

Low-dose radiation pretreatment improves survival of human ceiling culture-derived proliferative adipocytes (ccdPAs) under hypoxia via HIF-1 alpha and MMP-2 induction.

Poor survival is a major problem of adipocyte transplantation. We previously reported that VEGF and MMPs secreted from transplanted adipocytes are essential for angiogenesis and adipogenesis. Pretreatment with low-dose (5 Gy) radiation (LDR) increased VEGF, MMP-2, and HIF-1 alpha mRNA expression in human ceiling culture-derived proliferative adipocytes (hccdPAs). Gene expression after LDR differed between adipose-derived stem cells (hASCs) and hccdPAs. Pretreatment with LDR improved the survival of hccdPAs under hypoxia, which is inevitable in the early stages after transplantation. Upregulation of VEGF and MMP-2 after LDR in hccdPAs is mediated by HIF-1 alpha expression. Our results suggest that pretreatment with LDR may improve adipocyte graft survival in a clinical setting through upregulation of VEGF and MMP-2 via HIF-1 alpha.