From the Department of Plastic Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University; and the Department of Plastic and Cosmetic Surgery, Nanfang Hospital, Southern Medical University.
Plast Reconstr Surg. 2019 Dec;144(6):1323-1333. doi: 10.1097/PRS.0000000000006272.
Mature adipocytes dedifferentiate in vivo on application of a soft-tissue expander. Dedifferentiated adipocytes can proliferate and redifferentiate. This study used tissue expanders to pretreat adipose flaps, to increase the retention rate after fat graft.
A soft-tissue expander and silicone sheet were implanted beneath the left and right inguinal fat pads of rats, respectively. After 7 days of expansion, the adipose tissue derived from the pads was transplanted beneath dorsal skin. Samples were harvested at various time points, and histologic, immunohistochemical, and gene expression analyses were conducted. Mature adipocytes were cultured in vitro under a pressure of 520 Pa. Changes in cell morphology, the cytoskeleton, and expression of mechanical signal-related proteins were investigated.
Pressure in adipose flaps increased to 25 kPa on expansion. Mature adipocytes dedifferentiated following expansion. At 1 week after transplantation, the expression of vascular endothelial growth factor (p < 0.05) was higher in the expanded group. The retention rate at 12 weeks after transplantation was higher in the expanded group (56 ± 3 percent) than in the control group (32 ± 3 percent) (p < 0.05), and the surviving/regenerating zones (p < 0.01) were wider. The lipid content of mature adipocytes gradually decreased on culture under increased pressure, and these cells regained a proliferative capacity. This was accompanied by increased expression of mechanical signal--related proteins (p < 0.05).
Mechanical signals may induce dedifferentiation of mature adipocytes. Dedifferentiated adipocytes increase the retention rate of fat grafts by acting as seed cells.
在软组织扩张器的应用下，成熟脂肪细胞在体内去分化。去分化的脂肪细胞可以增殖和再分化。本研究使用组织扩张器预处理脂肪皮瓣，以增加脂肪移植后的保留率。
分别在大鼠左右腹股沟脂肪垫下方植入软组织扩张器和硅胶片。扩张 7 天后，从垫中提取脂肪组织移植至背部皮肤下。在不同时间点采集样本，并进行组织学、免疫组织化学和基因表达分析。将成熟脂肪细胞在 520 Pa 的压力下体外培养。研究细胞形态、细胞骨架和机械信号相关蛋白表达的变化。
脂肪皮瓣的压力在扩张时增加到 25 kPa。扩张后成熟脂肪细胞去分化。移植后 1 周，扩张组血管内皮生长因子的表达更高（p < 0.05）。移植后 12 周，扩张组的保留率（56 ± 3%）高于对照组（32 ± 3%）（p < 0.05），存活/再生区（p < 0.01）更宽。在增加压力下培养成熟脂肪细胞时，其脂质含量逐渐减少，这些细胞恢复了增殖能力。这伴随着机械信号相关蛋白表达的增加（p < 0.05）。
机械信号可能诱导成熟脂肪细胞去分化。去分化的脂肪细胞作为种子细胞增加脂肪移植的保留率。
