Enhancing Fat Graft Survival via Upregulating Autophagy of Adipocytes.

BACKGROUND: Autophagy is a cellular self-protection mechanism. The upregulation of adipose-derived stem cells' (ADSCs) autophagy can promote fat graft survival. However, the effect of interfering with adipocyte autophagy on graft survival is still unknown. In addition, autophagy is involved in adipocyte dedifferentiation. We investigated the effect of autophagy on adipocyte dedifferentiation and fat graft survival. METHODS: The classic autophagy regulatory drugs rapamycin (100 nM) and 3-methyladenine (3-MA; 10 mM) were used to treat adipocytes, adipocyte dedifferentiation was observed, and their effects on ADSCs were detected. In our experiments, 100 nM rapamycin, 10 mM 3-MA and saline were mixed with human adipose tissue and transplanted into nude mice. At 2, 4, 8 and 12 weeks postoperatively, the grafts were harvested for histological and immunohistochemical analysis. RESULTS: Rapamycin and 3-MA can promote and inhibit adipocyte dedifferentiation by regulating autophagy. Both drugs can inhibit ADSC proliferation, and 10 mM 3-MA can inhibit ADSC adipogenesis. At weeks 8 and 12, the volume retention rate of the rapamycin group (8 weeks, 64.77% ± 6.36%; 12 weeks, 56.13% ± 4.73%) was higher than the control group (8 weeks, 52.62% ± 4.04%; P < 0.05; 12 weeks, 43.17% ± 6.02%; P < 0.05) and the rapamycin group had more viable adipocytes and better vascularization. Compared with the control group, the volume retention rate, viable adipocytes and vascularization of the 3-MA group decreased. CONCLUSIONS: Rapamycin can promote adipocyte dedifferentiation by upregulating autophagy to promote fat graft survival. 3-MA can inhibit graft survival, but its mechanism includes the inhibition of adipocyte dedifferentiation and ADSC proliferation and adipogenesis. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Buccal Fat Pad Augmentation for Midfacial Rejuvenation: Modified Fat Grafting Technique and Ogee Line Remodeling.

BACKGROUND: The volume and position of the buccal fat pad (BFP) change with age, which manifests as a hollow midface. Previous studies showed that autologous fat grafting for BFP augmentation could effectively ameliorate midfacial hollowing. OBJECTIVES: The aim of this study was to introduce a modified fat grafting technique for female patients with midfacial hollowing to restore the volume of BFP, and to evaluate the safety and effectiveness of this approach. METHODS: Two cadavers were used for the dissection of the BFP and to demonstrate the surgical procedures. Forty-eight patients were treated for midfacial hollowing with the modified grafting strategy. The BFP was filled through a percutaneous zygomatic incision and an immediate amelioration in the hollow area was observed. Improvements were evaluated from measurements of the ogee line and ogee angle, FACE-Q questionnaires, and 3-party satisfaction ratings. Clinical profiles were reviewed and statistically analysed. RESULTS: The mean [standard deviation] ogee angle was 6.6° [1.9°] preoperatively and 3.9° [1.4°] postoperatively (average reduction, 2.7°). Patients' ogee lines were smoother postoperatively, with marked improvements in overall appearance, psychological well-being, and social confidence. Patients reported high satisfaction with decision-making and postoperative outcomes and felt 6.61 [2.21] years younger. Overall, 88%, 76%, and 83% of the cases were graded as good or excellent in improvement by surgeon, patient, and the third party, respectively. CONCLUSIONS: For age-dependent midfacial hollowing in female patients, the modified percutaneous grafting technique described here was safe and efficacious in restoring BFP volume. This technique produced a smoother ogee line and a natural, younger midfacial contour.

Delivery of microRNA-423-5p by exosome from adipose-derived stem/stromal cells inhibits DVL3 to potentiate autologous fat graft survival through adipogenesis and inflammatory response.

Autologous fat grafting represents a reconstructive technique but is limited by unstable graft retention. Based on existing reports and bioinformatics prediction, we hypothesized that delivering exosomes from human adipose-derived stem/stromal cells (hADSC-Exo) would increase fat graft survival and further explore the mechanism. hADSC-Exo were extracted and identified. An autologous fat grafting model was established using donor and recipient mice, followed by hADSC-Exo treatment. hADSC-Exo promoted the retention of autologous fat grafts in mice, along with increased adipocyte activity, angiogenesis, and decreased inflammation in grafts. Moreover, hADSC-Exo potentiated the adipose differentiation of 3T3-L1 cells, enhanced the angiogenic and migratory capacity of human umbilical vein endothelial cells, and inhibited the inflammation and viability of RAW 264.7 cells. The therapeutic effect of hADSC-Exo on fat grafting was associated with the delivery of microRNA (miR)-423-5p. Deletion of miR-423-5p in Exo impaired the function of hADSC-Exo on fat retention. miR-423-5p bound to DVL3 to suppress DVL3 expression, and DVL3 deletion promoted adipose differentiation of 3T3-L1 cells. In conclusion, our findings further widen the theoretical basis of the clinical application of hADSC-Exo in autologous fat grafts.

Evaluating the Efficacy of Dedifferentiated Fat Cells (DFATs) vs Adipose-Derived Stem Cells (ASCs) in Enhancing the Viability of Fat Grafts.

BACKGROUND: Enhancing graft fat survival remains a paramount challenge in autologous fat transplantation surgeries. Dedifferentiated fat cells (DFATs) and adipose-derived stem cells (ASCs) represent 2 pivotal cells with potential to improve fat graft survival rates. OBJECTIVES: In this study we aimed to compare the effectiveness of DFATs and ASCs in promoting fat graft survival, emphasizing their adipogenic and angiogenic capabilities. METHODS: Both in vitro and in vivo experiments were conducted. In vitro assessments compared adipogenesis, angiogenesis, osteogenesis, chondrogenesis, cell migration abilities, and surface markers. For in vivo evaluation, a cell-assisted lipotransfer animal model was employed to gauge graft volume retention and histological morphology. Analysis techniques included hematoxylin and eosin staining, Western blotting, and real-time polymerase chain reaction. RESULTS: In vitro findings suggested a slight superiority of DFATs in adipogenesis and angiogenesis compared to ASCs. In vivo tests demonstrated both cell types surpassed the control in terms of graft volume retention, with the DFATs group marginally outperforming in retention rates and the ASC group presenting a slightly enhanced graft tissue structure. CONCLUSIONS: Our study underscores the distinct advantages of DFATs and ASCs in bolstering fat graft survival, offering potentially novel insights for plastic surgeons aiming to elevate fat graft survival rates.

A Retrospective Analysis of Upper Arm Rejuvenation Surgery in 50 Patients.

BACKGROUND: Upper arm aesthetics often suffer from aging effects such as skin laxity and sagging due to collagen and elastin depletion. Fat loss, obesity, and weight fluctuations further exacerbate these issues. Existing classification systems for upper arm excess are complex and have practical limitations. OBJECTIVES: The aim of this study was to develop a more concise and clearer classification of upper arm excess that can guide surgical interventions effectively and assess clinical outcomes. METHODS: Patients undergoing upper arm rejuvenation surgery from January 2020 to January 2023 were categorized as mild, moderate, or severe. Mild cases underwent suction-assisted liposuction (SAL), moderate cases underwent radiofrequency-assisted liposuction combined with SAL, and severe cases underwent brachioplasty combined with SAL. Arm circumferences and BODY-Q questionnaires were collected pre- and postoperatively. RESULTS: The study included 50 female patients, aged 21 to 49 years. The average follow-up time was 7.5 [2.2] months. Arm circumference reduction rates were 6.8% in mild cases, 15.1% in moderate cases, and 17.3% in severe cases. Regarding the BODY-Q questionnaire for upper arms, the average score increased by 0.9 for mild, 2.1 for moderate, and 2.9 for severe cases. Complications were minimal, including 1 seroma and 2 cases of scar widening. CONCLUSIONS: The revised classification system for upper arm excess proved effective in guiding surgical decisions. Selecting the surgical approach based on severity resulted in satisfactory outcomes based on BODY-Q scores. This system offers a concise, objective, and practical tool for plastic surgeons.

The impact of SARS-Cov-2 infection on the periocular injection pain and hypersensitive reaction to botulinum toxin type A: results from clinical questionnaires.

Background: The COVID-19 pandemic has brought about significant changes in the medical field, yet the use of botulinum toxin type A has remained uninterrupted. Plastic surgeons must carefully consider the timing of administering botulinum toxin type A to patients who have recovered from COVID-19. Methods: A questionnaire survey was conducted among patients who had contracted and recovered from SARS-CoV-2 within a month. The survey aimed to investigate various indicators in patients who had received botulinum toxin A injections at the same site before and after their infection, including pain scores and allergic reactions and the occurrence of complications. Results: The pain scores of patients who contracted SARS-CoV-2 infection between 14-21 days post-infection exhibited significant variation from previous injections. However, patients who contracted the infection between 22-28 days post-infection did not exhibit significant variation from previous injections. Furthermore, the incidence of allergic reactions and complications following botulinum toxin injection within one month after contracting the infection did not significantly differ from that observed prior to infection. Conclusion: Administering botulinum toxin type A three weeks after COVID-19 recovery is a justifiable and comparatively secure approach.

Deep-learning based segmentation of ultrasound adipose image for liposuction.

BACKGROUND: To develop an automatic and reliable ultrasonic visual system for robot- or computer-assisted liposuction, we examined the use of deep learning for the segmentation of adipose ultrasound images in clinical and educational settings. METHODS: To segment adipose layers, it is proposed to use an Attention Skip-Convolutions ResU-Net (Attention SCResU-Net) consisting of SC residual blocks, attention gates and U-Net architecture. Transfer learning is utilised to compensate for the deficiency of clinical data. The Bama pig and clinical human adipose ultrasound image datasets are utilized, respectively. RESULTS: The final model obtains a Dice of 99.06 ± 0.95% and an ASD of 0.19 ± 0.18 mm on clinical datasets, outperforming other methods. By fine-tuning the eight deepest layers, accurate and stable segmentation results are obtained. CONCLUSIONS: The new deep-learning method achieves the accurate and automatic segmentation of adipose ultrasound images in real-time, thereby enhancing the safety of liposuction and enabling novice surgeons to better control the cannula.

Comparison of Microfat, Nanofat, and Extracellular Matrix/Stromal Vascular Fraction Gel for Skin Rejuvenation: Basic Animal Research.

BACKGROUND: Although stromal vascular fraction (SVF) cells and adipose-derived stem cells have well-defined antiaging effects on skin, certain disadvantages have limited their clinical application. OBJECTIVES: The aim of this study was to evaluate the effects of microfat, nanofat, and SVF-gel in improving ultraviolet (UV)-induced photoaged skin injury in nude mice. METHODS: After successfully establishing a photoaging model by UVA and UVB irradiation in nude mice, the back of each mouse was divided into 2 regions and randomly injected under the dermis with 0.5 mL of microfat, nanofat, SVF-gel, and phosphate-buffered saline. Inflammatory infiltration, dermis thickness, hydroxyproline content, Type I/Type III collagen ratio, elastic fiber morphology, skin cell proliferation, and adipocyte viability were measured. The overall structure of the skin was also observed by scanning electron microscopy. RESULTS: In the microfat group, the grafts survived well, with intact structure and viable adipocytes and little infiltration of inflammatory cells. Microfat promoted skin cell proliferation, collagen content increased, the ratio of Type I and III collagen reversed, and new oxytalan fibers formed, which to some extent improved the photoaging skin. In the nanofat and SVF-gel groups, a large amount of inflammatory cell infiltration and foam cell deposition in the grafts and dermis led to fibrosis and proliferation of skin tissue. Although the skin thickness and collagen content were also increased, these factors did not improve the photoaging skin. CONCLUSIONS: Microfat survives well, and improves photoaged skin injury in nude mice by promoting skin tissue regeneration and supplementing the capacity of subcutaneous adipose tissue.

Facial Rejuvenation and Contouring with Radiofrequency-Assisted Procedures in Asians.

Radiofrequency (RF)-assisted liposuction treatment is a minimally invasive skin-tightening technique for the patient population with skin laxity. The authors recommend facial liposuction combined with the RF procedure for the treatment of skin laxity. Minimal-invasive liposuction creates working channels for RF treatment and sufficiently exposes the subdermal fibrous septal network tissue so that the RF energy can directly act on the collagen of the fibrous septal network for thermal shrinkage, leading to better surgical results. In this article, the authors describe their preferred technique and experience for face rejuvenation and contouring.

Pyramidal multiple-theory (multi-type, multi-method and multi-layer) for facial fat grafting.

BACKGROUND: Age-related changes to the face pertinent anatomy and important aspects of autologous fat grafting have been widely applied in facial rejuvenation. Various types of autologous fat products (Macrofat, Microfat, SEFF, nanofat, and SVF-gel) with different properties and applicabilities have been introduced and available for surgeons. METHODS: Key differences between common techniques for fat processing and infiltration. Develop a plan for patients based on site-specific facial anatomical zones, we suggested a pyramidal multiple-theory (multi-type, multi-method and multi-layer) for facial fat grafting. Based on the complicated mechanism of the face decrepitude in different layers of facial soft tissue, autologous fat products with various particle sizes and components into different layers. RESULTS: Fifty-eight patients underwent this facial fat grafting strategy from June 2020 to Jan 2022. All achieved cosmetic improvements, with higher patients' satisfaction, and minor complications. Our facial fat grafting strategy takes advantage of different fat products and is able to address the physiological tissue changes during aging, more properly and targetedly, than the traditional facial fat grafting. CONCLUSIONS: Fat grafting to the face aids in volume restoration and rejuvenation, thereby addressing soft-tissue atrophy associated with the aging face, acquired conditions, or congenital malformations. The technique described as "lipo-tumescence" has been successfully used in the breast and other regions of the body that have radiation damage and is discussed in this article specifically for the face and neck.

Increased Fat Graft Survival by Promoting Adipocyte Dedifferentiation.

BACKGROUND: Some adipocytes undergo dedifferentiation after fat transplantation, and this may affect the survival of fat grafts. However, this effect has not been adequately studied. OBJECTIVES: This study aimed to clarify the effect of promoting the dedifferentiation of mature adipocytes on the survival of fat grafts. METHODS: Mature adipocytes and adipose stem cells (ASCs) were treated with OSI-906 (a specific inhibitor of insulin receptor and insulin-like growth factor-1 receptor) in vitro, and then the dedifferentiation of mature adipocytes and the proliferation of ASCs were evaluated. In the in vivo experiment, human lipoaspirates mixed with phosphate-buffered saline (Group A) or OSI-906 (Group B) were compared in nude mice. Grafts were harvested at 2, 8, and 12 weeks, and volume retention rate, histologic, and immunohistochemical analyses were conducted. RESULTS: OSI-906 can promote the dedifferentiation of mature adipocytes and inhibit the proliferation of ASCs. At 12 weeks, Group B showed a better volume retention rate (mean [standard deviation, SD], 62.3% [7.61%]) than group A (47.75% [6.11%]) (P < .05). Moreover, viable adipocytes and vascularization showed greater improvement in Group B than in Group A. CONCLUSIONS: This study suggests that promoting the dedifferentiation of mature adipocytes can improve the survival rate and quality of fat grafts.

[Autologous fat grafting for perioral and lower face rejuvenation].

Objective: To review the research progress of the application of autologous fat grafting in perioral and lower face rejuvenation. Methods: By extensively reviewing related articles and combining the clinical experiences, the anatomic features (fat compartments and blood supply), aging features of the perioral and lower face, and the application advancement and related complications of autologous fat grafting in this area were generally summarized. Results: The aesthetic features of perioral and lower face include the lip, chin, and so on, and the anatomic structures relating autologous fat grafting include the mandibular fat compartments, chin fat compartments, and other fat compartments. Meanwhile, the facial artery passes through this area and spreads out several important branches. The aging features of perioral and lower face include the depening of nasolabial fold, the aging lip, perioral wrinkles, "marionette lines", and so on. Autologous fat grafting can improve perioral and lower face rejuvenation by restoring volume loss of facial fat compartments, correcting aging malformation, and improving skin quality. But there are neurovascular injuries, facial aesthetic problems, and other related complications. Conclusion: Autologous fat grafting can be applied in perioral and lower face rejuvenation, and it can effectively improve related aging features. There are several aspects developing aggressively, including the research of facial asthetics features of Chinese people, combining autologous fat grafting with surgery as well as other methods to comprehensively treat facial aging, and the application of fat tissue related derivatives in perioral and lower face rejuvenation. However, the resorption rate of facial grafted fat tissue is still too high, and the long-term effectiveness can not be assured. In the future, the solutions related to improving the survival rate of grafted fat tissue need to be explored in the future.

An explainable machine learning method for assessing surgical skill in liposuction surgery.

PURPOSE: Surgical skill assessment has received growing interest in surgery training and quality control due to its essential role in competency assessment and trainee feedback. However, the current assessment methods rarely provide corresponding feedback guidance while giving ability evaluation. We aim to validate an explainable surgical skill assessment method that automatically evaluates the trainee performance of liposuction surgery and provides visual postoperative and real-time feedback. METHODS: In this study, machine learning using a model-agnostic interpretable method based on stroke segmentation was introduced to objectively evaluate surgical skills. We evaluated the method on liposuction surgery datasets that consisted of motion and force data for classification tasks. RESULTS: Our classifier achieved optimistic accuracy in clinical and imitation liposuction surgery models, ranging from 89 to 94%. With the help of SHapley Additive exPlanations (SHAP), we deeply explore the potential rules of liposuction operation between surgeons with variant experiences and provide real-time feedback based on the ML model to surgeons with undesirable skills. CONCLUSION: Our results demonstrate the strong abilities of explainable machine learning methods in objective surgical skill assessment. We believe that the machine learning model based on interpretive methods proposed in this article can improve the evaluation and training of liposuction surgery and provide objective assessment and training guidance for other surgeries.

Microliposuction and radiofrequency combined with the thread technique as a new method used in lower face lifting.

BACKGROUND: Minimally invasive facial rejuvenation is a popular and well-established treatment for patients seeking facial lifting. OBJECTIVE: The authors combined facial microliposuction, radiofrequency, and thread lifting technology as a comprehensive treatment (LRT) for facial rejuvenation in a case series of 57 patients. METHODS: A total of 76 patients underwent surgery and 75% completed 6 months of follow-up (57 patients); the patients were aged 26 to 51 (33.6 ± 4.5) years. All patients were followed up for hematoma within 1 week after the operation and for skin numbness and muscle paralysis at 1 week and 3 months postoperatively. Patient satisfaction with the postoperative aesthetic effects was analyzed by Face-Q™ at 6 months after the operation. RESULTS: The score for hematoma within 1 week was 1.21 ± 0.33, scores for postoperative skin numbness within 1 week and 3 months were 2.06 ± 0.51 and 1.17 ± 0.32, respectively, and scores for postoperative muscle paralysis within 1 week and 3 months were 1.31 ± 0.55 and 1.00 ± 0, respectively. Fifty-seven patients completed Face-Q™ (score: 22.1 ± 1.8, standard score: 82.2 ± 14.8). CONCLUSION: LRT is a minimally invasive method that can achieve a synergistic and satisfactory result for patients with mild to moderate facial skin sagging.

Function-preserving fat grafting in the breast: Results based on 18 years of experience.

BACKGROUND: Autologous fat transplantation has been used for breast nearly 40 years, but there are two main problems: the volume retention rate is unpredictable, leading to too many operations, and various complications, such as nodules, necrosis and calcification, occur. OBJECTIVE: The author proposed "function-preserving fat grafting" (FPFG) and reviewed the clinical data of patients from October 2002 to December 2020. METHODS: A total of 1218 patients underwent surgery, and 767 patients were followed up for more than half a year. Their ages ranged from 22 to 61 (31.9±10.1) years, and the BMI values ranged from 16.1 to 28.2 (20.6±2.73) kg/m2. Group I included 703 cases of breast aesthetic augmentation, group II included 38 cases of breast reconstruction after mastectomy (10 cases after radiotherapy and 7 cases after the Brava device was worn) and group III included 26 cases of simultaneous implant exchange with fat. RESULTS: At 6 months after the operation, 89.8% of the patients were satisfied with the outcome. For these patients, aesthetic augmentation required 1.9±0.73 procedures, and the unilateral breast injection volume was 180-380 ml (265.5±46.6); breast reconstruction required an average of 3.4±0.71 procedures, and the unilateral injection volume was 140-370 ml (233.9±67.7). The simultaneous implant exchange volume with fat was 160-320 ml (241.3±35.8 ml). There were 9 cases (1.2%) of palpable nodules, 3 cases of infection (0.39%), and no other severe complications. CONCLUSIONS: FPFG has the advantages of requiring few operations; leading to few necrosis, oil cysts and nodules; and leading to high postoperative satisfaction.

Types of periocular wrinkles based on anatomical and contractile characteristics of participating periocular muscles: A modified classification method and personalized injection technique.

BACKGROUND: Clinical classification methods for periocular wrinkles based on participating muscle behavior are lacking, and traditional treatment lacks detailed and individualized methods. AIMS: This study aimed to propose a modified classification system and individualized treatment for periocular wrinkles based on the participating muscles. PATIENTS/METHODS: Periocular wrinkles were classified into types I.I, I.II, I.III, II, and III. A personalized treatment pattern with a multipoint, low-dose technique was developed based on wrinkle classification and severity. Standard photographs were taken and assessments made at follow-up to evaluate wrinkle severity. RESULTS: Wrinkle severity was reduced at 1 and 3 months after periorbital botulinum toxin injection, and no serious adverse events were recorded. CONCLUSIONS: Periorbital wrinkles were classified according to participating muscles. The modified injection pattern was individualized, effective, and safe for the treatment of periorbital wrinkles.

The Importance of Protecting the Structure and Viability of Adipose Tissue for Fat Grafting.

BACKGROUND: Fat grafting is widely used for soft-tissue augmentation; however, the related clinical outcome remains variable and technique-dependent. The mechanisms underlying fat graft survival are not fully understood, particularly regarding the contributions of different cell types, such as functional adipocytes. This study evaluated the importance of adipose tissue structure and viability in fat grafting and, to some extent, revealed the effect of adipocytes in fat grafting. METHODS: Human lipoaspirate was harvested using suction-assisted liposuction and processed using three separate methods: cotton-pad filtration, soft centrifugation (400 g for 1 minute), and Coleman centrifugation (1200 g for 3 minutes). Then all samples were subjected to second cotton-pad concentration. Adipose tissue structure and viability, the numbers of adipose-derived stem cells, and their proliferation and multilineage differentiation abilities were compared in vitro. The volume retention rate and fat graft quality were evaluated in vivo. RESULTS: Cell structure destruction and viability decline were more evident in the Coleman centrifugation group compared to the cotton-pad filtration group and the soft centrifugation group. However, no intergroup differences were observed in the numbers, proliferation, or multilineage differentiation abilities of adipose-derived stem cells. After transplantation, the volume retention rates were similar in the three groups. However, greater structural and functional damage was associated with poorer graft quality, including decreased levels of graft viability, vessel density, and vascular endothelial growth factor secretion and increased levels of vacuoles, necrotic areas, fibrosis, and inflammation. CONCLUSIONS: Protecting adipose tissue structure and viability is crucial for improving fat grafting outcomes. CLINICAL RELEVANCE STATEMENT: The protection of the structure and viability of adipose tissue should be ensured throughout the whole process of fat grafting to reduce complications and improve graft quality.

[Research progress of external volume expansion assisted autologous fat grafting for breast reconstruction].

Objective: To review the application progress, mechanism, application points, limitations, and oncological safety of external volume expansion (EVE) assisted autologous fat grafting for breast reconstruction and provide a reference for optimizing the design of EVE. Methods: Based on the latest relevant articles, the basic experiments and clinical applications of EVE were summarized. Results: EVE can reduce interstitial fluid pressure, increase blood supply, and promote adipogenic differentiation, thereby benefiting the survival of transplanted fat. EVE assisted autologous fat grafting in clinical practice can improve the retention rate of breast volume and the outcome of breast reconstruction, meanwhile it doesn't increase the risk of local recurrence. But there is no standard parameters for application, and there are many complications and limitations. Conclusion: EVE improves the survival of transplanted fat, but its complications and poor compliance are obvious, so it is urgent to further investigate customized products for breast reconstruction after breast cancer and establish relevant application guidelines.

Washing Lipoaspirate Improves Fat Graft Survival in Nude Mice.

BACKGROUND: The optimal fat processing technique of fat grafting has not been determined. We have proved the importance of washing lipoaspirate to remove blood, but the necessity of washing when there is no obvious bleeding during liposuction is not clear. OBJECTIVES: The purpose of this study is to further investigate the effect of washing on fat graft survival and the underlying mechanisms, from the perspective of inflammation, oxidative stress and apoptosis. METHODS: To exclude the influence of blood, de-erythrocyte infranatant (dEI) isolated from lipoaspirate was obtained. Purified fat processed by cotton pad filtration mixed with dEIs after sedimentation (sedimentation group), washing (washing group) or phosphate buffer solution (control group) was transplanted to nude mice subcutaneously. Samples were harvested at 1 day and 1, 3, 8 weeks after transplantation. Volume and weight retention, histologic examination, immunostaining of perilipin-1, CD31, CD45 and Ly6g, mRNA expression of PPAR-γ, C/EBPα, VEGF, bFGF, IL-6, IL10, TNF-α, TGF-ß, Bax and Bcl-2, and protein contents of 8-iso-PGF2α, IL-6, IL10, TNF-α and TGF-ß were all compared among groups. RESULTS: After transplantation, volume and weight retention, histologic scores, viable adipocytes and vascularization were all improved in the washing group, with increased expression of adipogenic and angiogenic genes. Compared with the sedimentation group, the washing group had milder inflammation, lower levels of oxidative stress and apoptosis. CONCLUSIONS: Washing lipoaspirate to eliminate mixed components can improve fat graft survival and promote adipogenesis and angiogenesis, possibly by relieving inflammation, reducing oxidative stress injury and inhibiting apoptosis. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of 47 these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .