BACKGROUND: The tear trough deformity is a sign of eye aging. Filling is an ideal choice for the tear trough accompanied by infraorbital hollows. OBJECTIVE: To evaluate the efficacy and safety of stromal vascular fraction gel (SVF-gel) as a filler for the tear trough deformity which is combined with infraorbital hollows. MATERIALS AND METHODS: From July 2017 to June 2018, 33 patients underwent autologous fat aspiration and were followed up successfully. Stromal vascular fraction gel was used to correct patients with bilateral Barton Ⅰ/Ⅱ tear trough deformity and infraorbital hollows. Improvement was evaluated by measuring skin-periosteal depth, 3D volume, global aesthetic improvement scale (GAIS), and patient self-assessment. RESULTS: Skin-periosteal depth improved significantly ( p < .001). The volumetric increment of the tear trough and infraorbital regions increased 2.132 ± 0.671 mL, and the retention rate was excellent (72.87 ± 10.23%). The GAIS showed a high score (2.5 ± 0.5 points), with patient self-assessment showing satisfactory results for all 7 questions on the questionnaire. CONCLUSION: The high retention rate of SVF-gel suggests that it can provide an effective solution to tear trough deformity accompanied by infraorbital hollows.

Autologous fat grating is a widely-accepted method to correct soft tissue deficiency. Although fat transplantation shows excellent biocompatibility and simple applicability, the relatively low retention rate caused by fat necrosis is still a challenge. The vasculature is integral after fat grafting, serving multiple crucial functions. Rapid and effective angiogenesis within grafts is essential for supplying oxygen necessary for adipocytes’ survival. It facilitates the influx of inflammatory cells to remove necrotic adipocytes and aids in the delivery of regenerative cells for adipose tissue regeneration in fat grafts. The vasculature also provides a niche for interaction between adipose progenitor cells and vascular progenitor cells, enhancing angiogenesis and adipogenesis in grafts. Various methods, such as enriching grafts with diverse pro-angiogenic cells or utilizing cell-free approaches, have been employed to enhance angiogenesis. Beige and dedifferentiated adipocytes in grafts could increase vessel density. This review aims to outline the function of vasculature in fat grafting and discuss different cell or cell-free approaches that can enhance angiogenesis following fat grafting.

Autologous fat grafting is becoming increasingly common worldly. However, the long-term retention of fat grafting is still unpredictable due to the inevitable fibrosis arising during tissue repair. Fibrosis may be regulated by T-cell immune responses that are influenced by adipose-derived stem cells (ASCs). Therefore, we hypothesized that overly abundant ASCs might promote fibrosis by promoting T-cell immune responses to adipose tissue. We performed 0.3 ml fat grafts with 10⁴/ml, 10⁶/ml and 10⁸/ml ASCs and control group in C57 BL/6 mice in vivo. We observed retention, fibrosis, T-cell immunity, and macrophage infiltration over 12 weeks. Besides, CD4+ T-helper 1 (Th1) cells and T-helper 2 (Th2) cells were co-cultured with ASCs or ASCs conditioned media (ASCs-CM) in vitro. We detected the ratio of Th2%/Th1%. Results showed that the retention rate was higher in 10⁴ group, while even lower in 10⁸ group with significantly increased inflammation and fibrosis than control group at week 12 in vivo. There was no significance between control group and 10⁶ group. Also, 10⁸ group increased the infiltration of M2 macrophages, CD4+ T-cells and Th2/Th1 ratio. In vitro, the ratio of Th2%/Th1% induced by ASCs-transwell group was higher than ASCs-CM group and showed concentration-dependent. Accordingly, high concentrations of ASCs in adipose tissue can promote Th1–Th2 shifting, and excessive Th2 cells might promote the persistence of M2 macrophages and increase the level of fibrosis which lead to a decrease in the long-term retention of fat grafts. Also, we found ASCs promoted Th1–Th2 shifting in vitro.

Fat grafting is a popular operative approach for rejuvenation. Some patients requiring facial fat grafting also have acne. Fat grafting may improve acne in some patients. The aim of this study was to assess whether fat grafting can improve acne and to analyze the mechanism of action by which such improvement occurs. Preoperative and postoperative digital photographs were examined retrospectively in 229 patients who underwent fat grafting to compare the numbers of inflammatory acne lesions. In addition, 18 patients with acne who were treated by injection of subdermal stromal vascular fraction gel (SVF-gel) were examined prospectively. The numbers of inflammatory acne lesions before and after treatment were measured, and changes in the levels of CD4⁺ T-cell infiltration were determined from immunohistochemical staining. Of the 229 retrospectively evaluated patients who underwent fat grafting, 22 had acne and had complete follow-up data; in these patients, the numbers of acne lesions were significantly lower after than before treatment. The 18 patients who received subdermal SVF-gel injection showed evident improvements in inflammatory lesions after more than 1 year of follow-up. CD4⁺ T-cell infiltration was significantly decreased at week 4. Facial fat grafting can improve inflammatory acne lesions, perhaps because adipose-derived stem cells, which are plentiful in SVF-gel, reduce CD4⁺ T-cell-mediated inflammation responses.

At present, fat transplantation is widely used in the plastic surgery industry, but the long-term preservation rate of transplanted fat decreases because of complications such as oil cysts due to the inability in macrophages to metabolize absorption. In cell-assisted lipotransfer technology, adipose-derived stem cells (ASCs) can influence the inflammatory response of grafts through the immunoregulation in macrophages, and the lipid metabolism in macrophages plays an important role in this process. Therefore, we hypothesized ASCs could improve the retention rate of fat grafts by regulating the progress of lipid metabolism in macrophages. We established fat transplantation and ASC-assisted fat transplantation model in C57BL/6 mice in vivo, and bone marrow-derived macrophages cocultured with apoptotic adipocytes were treated with or without ASCs in vitro. Graft retention, tissue structure, fibrosis, macrophage phenotype transformation, lipid deposition, mitochondrial morphology, oxygen consumption rate (OCR), fatty acid β-oxidation (FAO) level, and ATP production were assessed. Additionally, fat transplantation and ASC-assisted fat transplantation model was treated with etomoxir which inhibits mitochondrial FAO. Macrophages pretreated with etomoxir were co-cultured with apoptotic adipocytes and treated with or without ASCs. The method aboved was used for detection and verification. In vivo, ASC-assisted fat transplantation improved macrophage mitochondrial expression and FAO level, promoted the early transformation of M2 macrophages, reduced the long-term lipid deposition of macrophages, and improved the retention rate of fat grafts. In vitro, ASCs up-regulated the level of mitochondrial FAO, OCR and ATP production in macrophages, reduced lipid deposition of macrophages and promoted M2 macrophages polarization by paracine function. The ability of ASCs in group pretreated with etomoxir to reduce the foaming of macrophages, promote the transformation to M2 macrophages, and improve the retention rate of fat transplantation was weakened. ASCs increased the retention rate of transplanted fat by upregulating mitochondrial FAO to promote M2 polaration in macrophages. In addition, ASCs up-regulate mitochondrial FAO by paracrine effect to reduce foam cells formation and promote M2 transformation in macrophages in vitro.