Phipps Kyle D, Gebremeskel Simon, Gillis Joshua, Hong Paul, Johnston Brent, Bezuhly Michael
Halifax, Nova Scotia, Canada From the Faculty of Medicine, the Departments of Immunology and Microbiology, Pathology, and Pediatrics, and the Divisions of Plastic and Reconstructive Surgery and Otolaryngology, Dalhousie University.
Plast Reconstr Surg. 2015 Jan;135(1):140-149. doi: 10.1097/PRS.0000000000000793.
Variability in graft retention with subsequent undercorrection remains a significant limitation of autologous fat grafting. The authors evaluated whether graft retention in a mouse model could be improved via graft supplementation with alternatively activated M2 macrophages, cells known to play a critical role in tissue repair.
Grafts from C57BL/6 mouse inguinal fat pads were supplemented with M2 macrophages generated by intraperitoneal Brewer's thioglycollate injection and in vitro culture. Grafts with saline or M2 macrophages were injected under recipient mouse scalps and assessed by serial micro-computed tomographic analysis. Explanted grafts underwent immunohistochemical and flow cytometric analyses. M2 culture supernatants were added to stromal vascular fraction adipose-derived stem cells to assess adipogenic gene expression induction.
One month after graft injection, no significant difference was noted between M2 macrophage-supplemented (105 ± 7.0 mm) and control graft volumes (72 ± 22 mm). By 3 months after injection, M2 macrophage-supplemented grafts remained stable, whereas controls experienced further volume loss (103 ± 8 mm versus 39.4 ± 15 mm; p = 0.015). Presence of macrophages in supplemented grafts was confirmed by flow cytometry. M2 macrophage-supplemented grafts exhibited a 157 percent increase in vascular density compared with controls (p < 0.05). Induction of adipogenic C/EBPα gene expression was observed with M2 supernatants addition to stromal vascular fraction adipose-derived stem cells.
M2 macrophages improve autologous fat graft volume retention by stimulating angiogenesis. These findings provide proof-of-principle for development of fat grafting techniques that harness reparative properties of M2 macrophages.
移植脂肪留存率存在差异并伴有后续矫正不足，仍然是自体脂肪移植的一个重大局限。作者评估了在小鼠模型中，通过向移植脂肪补充交替活化的M2巨噬细胞（已知在组织修复中起关键作用的细胞），是否能够提高移植脂肪的留存率。
将通过腹腔注射布鲁尔氏巯基乙酸盐并进行体外培养产生的M2巨噬细胞，补充到C57BL/6小鼠腹股沟脂肪垫的移植物中。将含有生理盐水或M2巨噬细胞的移植物注射到受体小鼠头皮下，并通过连续微计算机断层扫描分析进行评估。对取出的移植物进行免疫组织化学和流式细胞术分析。将M2培养上清液添加到基质血管成分脂肪来源干细胞中，以评估成脂基因表达诱导情况。
移植后1个月，补充M2巨噬细胞的移植物（105±7.0立方毫米）与对照移植物体积（72±22立方毫米）之间未观察到显著差异。注射后3个月，补充M2巨噬细胞的移植物保持稳定，而对照移植物体积进一步减小（103±8立方毫米对39.4±15立方毫米；p = 0.015）。通过流式细胞术证实了补充移植物中存在巨噬细胞。与对照相比，补充M2巨噬细胞的移植物血管密度增加了157%（p < 0.05）。向基质血管成分脂肪来源干细胞中添加M2上清液后，观察到成脂C/EBPα基因表达的诱导。
M2巨噬细胞通过刺激血管生成来提高自体脂肪移植物的体积留存率。这些发现为开发利用M2巨噬细胞修复特性的脂肪移植技术提供了原理证明。
