From the Department of Plastic and Cosmetic Surgery, Nanfang Hospital, Southern Medical University.
Dermatology Department, First People's Hospital of Yunnan Province.
Plast Reconstr Surg. 2023 Sep 1;152(3):446e-457e. doi: 10.1097/PRS.0000000000010259. Epub 2023 Feb 1.
Low early macrophage fat graft infiltration (within a week of surgery) hinders tissue regeneration, suggesting that macrophages play a vital role in early angiogenesis and adipogenesis. However, the source of macrophages during this period is unclear.
C57BL/6 mice were split into fascial removal (FR) group and control groups (CG). Mice had a piece of back fascia removed in the FR group, which was immediately replaced in the CG, and inguinal fat injected into the transplantation site of both groups. Separately, fascia was harvested from green fluorescent protein-expressing mice and transplanted into C57BL/6 mice for tracing macrophage infiltration after fat grafting.
The number of capillaries in the FR group was lower than that in the CG at days 3 ( P < 0.01) and 7 ( P < 0.05). Moreover, the number of small adipocytes in the FR group was lower than in the CG on days 3, 7, and 14 (all P < 0.05), and the relative expression of several adipogenic proteins was significantly lower in the FR group than in the CG on days 14 and 30. The timeline of macrophage infiltration was consistent with angiogenesis and adipogenesis. The number of macrophages in the FR group was significantly lower than in the CG at days 3 and 7 ( P < 0.05), and there were more fascia-derived macrophages than circulation-derived macrophages infiltrated into fat grafts within 7 days. Finally, the graft retention was lower in the FR group than the CG at day 90 ( P < 0.05).
In the early stage after fat grafting, fascial macrophage infiltration initiates tissue regeneration, thereby improving graft retention by promoting angiogenesis and adipogenesis.
In the clinic, injecting fat close to the fascia may increase fat retention. Fascia is widespread and self-regenerating, which may be a promising alternative source of local macrophages, with implications for tissue-engineering therapies such as correction of soft-tissue defects and breast reconstruction.
脂肪移植后早期（术后一周内）巨噬细胞浸润不足会阻碍组织再生，这表明巨噬细胞在早期血管生成和脂肪生成中起着至关重要的作用。然而，在此期间巨噬细胞的来源尚不清楚。
将 C57BL/6 小鼠分为筋膜去除（FR）组和对照组（CG）。FR 组的小鼠背部筋膜被切除，CG 组的筋膜被立即替换，腹股沟脂肪被注射到两组的移植部位。此外，从绿色荧光蛋白表达的小鼠中提取筋膜，并将其移植到 C57BL/6 小鼠体内，以追踪脂肪移植后巨噬细胞的浸润情况。
FR 组在第 3 天（P<0.01）和第 7 天（P<0.05）的毛细血管数量低于 CG 组。此外，FR 组的小脂肪细胞数量在第 3、7 和 14 天均低于 CG 组（均 P<0.05），在第 14 天和第 30 天，FR 组的几个脂肪生成蛋白的相对表达水平明显低于 CG 组。巨噬细胞浸润的时间线与血管生成和脂肪生成一致。在第 3 天和第 7 天，FR 组的巨噬细胞数量明显低于 CG 组（P<0.05），并且在 7 天内，有更多的筋膜来源的巨噬细胞浸润到脂肪移植物中，而不是循环来源的巨噬细胞。最后，FR 组的移植物保留率在第 90 天低于 CG 组（P<0.05）。
脂肪移植后早期，筋膜巨噬细胞浸润启动组织再生，从而通过促进血管生成和脂肪生成来提高移植物保留率。
在临床上，将脂肪注射到靠近筋膜处可能会增加脂肪的保留率。筋膜广泛存在且具有自我再生能力，这可能是局部巨噬细胞的一种有前途的替代来源，对组织工程治疗具有重要意义，例如纠正软组织缺损和乳房重建。
