Investigation of the Effect of Mobile and Immobile Regions on Fat Graft Viability: An Experimental Study in a New Model.

BACKGROUND: Fat grafts are widely used in plastic, aesthetic and reconstructive surgery. Their unpredictable resorption is their main disadvantage. A review of the literature shows that there is a lack of research on the effect of mobile and immobile regions on fat graft survival in fat graft applications. OBJECTIVE: Our aim was to investigate the relationship of fat graft survival with mobile and immobile region in a new experimental model. METHODS: Twenty-four male Wistar albino rats were randomly divided into two groups (n=12). Fat grafts were harvested from the right inguinal region of the rat. In Group 1, the fat graft was placed in the subcutaneous pouch formed in the scalp region of the rat. In Group 2, fat grafts were placed in the pouch formed in the posterior cervical region of the rat. At the end of 6 weeks, the weights and histopathology of the fat grafts were evaluated. Histopathological examinations were performed in a blinded fashion. RESULTS: The weights of the fat grafts were found to be higher in Group 1. At the same time, histopathological examinations showed that vascular density was higher in Group 1. There was no statistically significant difference in other histopathological examinations. CONCLUSION: The mobile and immobile areas may have different effects on the survival of transplanted fat grafts. Sliding movement between muscle and skin in the mobile zone puts stress on the fat graft. In our study, the mobile site was shown to have a negative effect on the vascularity of the fat graft. It was observed that the vascular density was higher in the fat graft placed in the immobilised area. Further studies on the increase in vascularity can be carried out using the new experimental model we have created. 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 .

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 .

Effects of Oleuropein Oral Intake on Infected Fat Grafts: Experimental Study.

AIM: The aim of this study was to evaluate the effects of oleuropein oral intake on infected fat grafts and fat graft survival. MATERIALS AND METHODS: 32 Wistar albino rats were divided into four groups: 0. none treated, 1. serum oral intake, 2. antibiotic oral intake, and 3. oleuropein oral intake. The dorsal regions of the rats were separated into four quadrants as right and left cranial, and right and left caudal to determine each quadrant where fat grafts were placed. Right cranial and caudal quadrants were infected with the methicillin-susceptible Staphylococcus aureus (MSSA) strain. The left cranial and caudal quadrants were infected with the Pseudomonas aeruginosa strain. On the 7th day and end of the 3rd month, fibroblast density, inflammation, and fat survival were demonstrated immunohistochemically with FGF, CD68, and perilipin (PP), respectively. RESULTS: On the 7th day, for P. aureginosa-infected grafts, oleuropein was shown higher rates in CD68 and PP staining compared to the antibiotic group (p < 0.05, p < 0.001, respectively). At the end of the 3rd month, for P. aureginosa and S. aureus-infected grafts, the oleuropein group was demonstrated improved PP staining rates compared to the antibiotic group (p < 0.01, p < 0.01, respectively). CONCLUSION: Oleuropein as a natural olive leaf extract with potent antioxidant, anti-inflammatory, and antimicrobial features is an alternative and supportive agent for both treatment and prophylaxis of surgical site infections like the antibiotics of chemical synthesis. P. aeruginosa and S. aureus surgical site infections could treat and prevent safely and effectively by oleuropein, particularly in early and late periods after surgery. 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 .

LRG-1 promotes fat graft survival through the RAB31-mediated inhibition of hypoxia-induced apoptosis.

Autologous adipose tissue is an ideal soft tissue filling material, and its biocompatibility is better than that of artificial tissue substitutes, foreign bodies and heterogeneous materials. Although autologous fat transplantation has many advantages, the low retention rate of adipose tissue limits its clinical application. Here, we identified a secretory glycoprotein, leucine-rich-alpha-2-glycoprotein 1 (LRG-1), that could promote fat graft survival through RAB31-mediated inhibition of hypoxia-induced apoptosis. We showed that LRG-1 injection significantly increased the maintenance of fat volume and weight compared with the control. In addition, higher fat integrity, more viable adipocytes and fewer apoptotic cells were observed in the LRG-1-treated groups. Furthermore, we discovered that LRG-1 could reduce the ADSC apoptosis induced by hypoxic conditions. The mechanism underlying the LRG-1-mediated suppression of the ADSC apoptosis induced by hypoxia was mediated by the upregulation of RAB31 expression. Using LRG-1 for fat grafts may prove to be clinically successful for increasing the retention rate of transplanted fat.

Quercetin May Improve Fat Graft Survival by Promoting Fat Browning Peripherally.

BACKGROUND: Adipose browning occurs after white fat transfer. But its location and effects on fat graft survival remains controversial. This study was performed to locate the browning of fat grafts, and to explore the effects of quercetin on fat graft browning and fat graft survival. METHODS: Human fat granules were injected into the subcutaneous layer of 12 nude mice. Control group was injected with fat granules and 10% of normal saline, while quercetin group was injected with fat granules and 10% of quercetin. The graft samples (n = 6 for each group) were obtained in weeks 2, 4, 8 and 12. Weight retention rate of the grafts was calculated. Gene and protein expression of mitochondrial markers (silent information regulator 1, SIRT1; heat shock protein 60, HSP60), browning marker (uncoupling protein 1, UCP1), peroxisome proliferator-activated receptor-γ (PPAR-γ), vascular endothelial growth factor A (VEGF-A) were evaluated. Hematoxylin and eosin staining and anti-UCP1 staining were performed. RESULTS: Clusters of small multilocular beige adipocytes were observed in the periphery of fat grafts. Compared with control group, quercetin group had a higher weight retention rate, a higher gene/protein expression of SIRT1, HSP60, UCP1, PPAR-γ and VEGF-A, and a higher occurrence of peripheral adipose browning. CONCLUSIONS: Peripherally located adipose browning occurred after white fat transfer. It can be enhanced by the addition of quercetin through promoting mitochondrial function of fat cells, and may be one of the mechanisms that quercetin improves fat graft survival. 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 .

"Fasting: An Effective Preconditioning Method to Increase Fat Graft Survival".

BACKGROUND: Most preconditioning techniques before fat grafting require external manipulation. Since nutrition is the main factor maintaining the balance of lipogenesis and lipolysis, we hypothesized that fasting before undergoing autologous fat grafting may increase lipolysis and reduce adipocyte size, thereby improving the fat graft survival rate. METHODS: C57BL/6 mice were divided into 24 h starved or fed groups. Adipose tissue lipolysis, adipogenesis, and angiogenesis-related gene expression, in fat from both groups, were analyzed. The volume and weight of the grafted fat at 4-8 weeks postoperatively were measured using micro-computed tomography. Immunohistochemistry staining and mRNA expression analysis were also performed to evaluate the effect of fasting on fat graft survival. RESULTS: Fasting decreased adipocyte size by inducing adipose tissue lipolysis. Adipogenesis-related genes were remarkably downregulated while lipolysis-related genes and angiogenesis inducer genes were significantly upregulated in the starved adipose tissue. The mice grafted with the fat from the 24 h starved group had approximately 20% larger volumes and considerably heavier weights than those from the fed group. Increased viable adipocytes and vessels, and reduced macrophages in the fat grafts obtained from the 24 h starved group were also observed. CONCLUSIONS: Fasting for 24 h before harvesting fat increased the retention volume of fat graft by increasing angiogenesis via VEGF induction. Therefore, fasting would be a novel and reliable preconditioning strategy to improve graft survival in autologous fat grafting. 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.

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 .

Effects of Cigarette Smoke on Fat Graft Survival in an Experimental Rat Model.

INTRODUCTION: A fat graft is the closest thing to being the ideal soft tissue filler. Although it has many advantages, reliability of late-term survival is a never-ending debate. Although there are observational studies that research the effect of cigarette smoke on fat graft take in clinical setting, there has not been an objective experimental animal study on the affect of smoking on fat graft survival. The aim of our study is to search if smoking has an affect on fat grafts. MATERIALS AND METHODS: Twenty-two Sprague-Dawley type rats were used. Exposure was maintained via a passive smoke exposure system. Rats were divided into three groups regarding their exposure period. At the end of the study, transferred fat grafts were extracted and weighed with a precision scale, an arterial blood sample was taken for biochemical analysis, and grafts were sent to the pathology laboratory for immunohistochemical assessment. RESULTS: There were meaningful differences between the control group and the other two groups in graft weight loss, serum cotinine, tissue MDA, adipose tissue/fibrosis ratio, stem cell counts, perilipin positive cell density and inflammation density. Furthermore, we detected meaningful correlations between serum cotinine, tissue MDA and graft weight loss. CONCLUSION: Fat graft takes with the same mechanisms as a wound heals. So like wound healing, cigarette smoke has a negative affect on fat graft survival. A fat graft is by its nature an elective procedure so to improve our late-term success, cigarette smoke exposure should be kept to a minimum for increased reliability. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each article. 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 .

The effect of host tissue and radiation on fat-graft survival: A comparative experimental study.

Because lipofilling is often associated with various reconstructive procedures, especially breast reconstructions, improving fat-graft retention remains a major concern for plastic surgeons. We conducted an experimental protocol in a rat model simulating an autologous breast reconstruction method using the fat-augmented latissimus dorsi myocutaneous (LDM) flap. This study aimed to compare the survival rates of autologous adipocytes when injected subcutaneously and intramuscularly and to evaluate the role of recipient host tissue, volume of the injected fat, and postoperative radiation on fat-graft retention. Thirty rats were divided into five groups (A, B, C, D, and E), of six rats each. All animals underwent a pedicled LDM flap transfer to the anterior thoracic wall, and different volumes of autologous fat were injected into three recipient areas, namely, the pectoralis major and latissimus dorsi muscles and the subcutaneous tissue of the flap's skin island, as follows: 1 mL of fat was injected in total in group A, 2 mL in groups B and D, and 5 mL in group C. Group D animals received postoperative radiation (24 Gy), whereas group E animals (controls) did not undergo any fat grafting procedure. Eight weeks after surgery, adipocyte survival was assessed in all groups using histological and immunochemistry techniques. The results showed that the pectoralis major muscle was the substrate with the highest adipocyte survival rates, which were proportional to the amount of fat injected, followed by the latissimus dorsi muscle and the subcutaneous tissue. Increased volumes of transplanted fat into the subcutaneous tissue did not correspond to increased adipocyte survival. Irradiation of host tissues resulted in a statistically significant decrease in surviving adipocytes in all three recipient sites (p<0.001). Our study strongly suggests that muscle ensures optimal fat-graft retention, whereas postoperative radiation negatively affects adipocyte survival following fat transplantation.

Salvianolic acid-B improves fat graft survival by promoting proliferation and adipogenesis.

BACKGROUND: Our previous study proved that Salvia miltiorrhiza could enhance fat graft survival by promoting adipogenesis. However, the effect of salvianolic acid B (Sal-B), the most abundant and bioactive water-soluble compound in Salvia miltiorrhiza, on fat graft survival has not yet been investigated. OBJECTIVE: This study aims to investigate whether salvianolic acid B could improve fat graft survival and promote preadipocyte differentiation. The underlying mechanism has also been studied. METHODS: In vivo, 0.2 ml of Coleman fat was transplanted into nude mice with salvianolic acid B. The grafts were evaluated by HE and IF at 2 and 4 weeks posttransplantation and by micro-CT at 4 weeks posttransplantation. In vitro, the adipogenesis and proliferative activities of salvianolic acid B were analyzed in cultured human adipose-derived stem cells (h-ADSCs) and 3T3-L1 cells to detect the mechanism by which salvianolic acid B affects graft survival. RESULTS: In vivo, the weights and volumes of the fat grafts in the Sal-B-treated groups were significantly higher than those of the fat grafts in the control group. In addition, higher fat integrity and more viable adipocytes were observed in the Sal-B-treated groups. In vitro, salvianolic acid B showed the ability to promote 3T3-L1 and h-ADSC proliferation and adipogenesis. CONCLUSIONS: Our in vitro experiments demonstrated that salvianolic acid B can promote the proliferation of adipose stem cells and enhance the differentiation of adipose stem cells. Simultaneously, in vivo experiments showed that salvianolic acid B can improve the survival rate of fat transplantation. Therefore, our research shed light on the potential therapeutic usage of salvianolic acid B in improving the survival rate of fat transplantation.

Cosmetic Fat Transplantation: A Review.

AIM: To review current techniques used in fat grafting to optimise graft persistence and achieve optimal cosmetic outcomes. BACKGROUND: Fat transplantation has been used extensively in the reconstruction and cosmetic industry for many years. However, there is significant adipocyte loss and reabsorption rates, leading to the loss of external cosmetic volume and the need for repeat procedures. Adipocyte loss can occur at all four stages of transplantation and this review discusses each of these methods with the aim being to optimise graft outcome. RESULTS: Several new techniques have been discussed including liposuction techniques, fat processing, and assisted fat grafting which show an improvement in adipocyte survival, revasculisation and graft outcomes. CONCLUSION: There have been many improvements in fat grafting and the implementation of these will optimise surgical outcomes but there are still strategies to improve further. However, there is still a lack of standardised techniques and training. More research is needed in the areas of fat processing and the use of additives to the fat graft. More clinical research is needed in the fat placement technique, which has very little published evidence and current techniques are mostly anecdotal by cosmetic surgeons.

The Science of Fat Grafting.

Autologous fat grafting has become a popular and well-established technique used by plastic surgeons in a variety of aesthetic and reconstructive procedures. An understanding of the basic science principles underlying fat grafting is crucial to explaining its extensive utility for soft tissue rejuvenation, volume augmentation, and body contouring-and the unpredictable fat resorption rates after grafting that pose a significant challenge for plastic surgeons. While the scientific principles of fat grafting can theoretically be exploited to optimize fat grafting techniques and increase fat tissue survival, a consensus has yet been established as to the best practices for this procedure. This review discusses the biology of adipose tissue and the scientific principles behind its behavior and survival in autologous fat grafting.

Fat grafting to the face with adjunctive microneedling: a simple technique with high patient satisfaction

Background/aim: Even though new techniques are emerging to overcome the inconsistent long-term viability of fat grafts, current methods for increasing fat graft survival are not routinely adaptable to all clinical environments. The purpose of this study was to determine the efficacy of microneedling as an adjunct to fat grafting to the face. Materials and methods: Twenty-two patients that underwent fat grafting to the face with adjunctive microneedling were evaluated in terms of improvement in facial skin quality and facial volume and their results were compared to those in 18 patients that underwent fat grafting without microneedling. The evaluation was conducted with a modification of the Global Aesthetic Improvement Scale at the postoperative third month. Results: All patients that underwent fat grafting and microneedling demonstrated "much improvement" in skin quality and volume at the postoperative third month while "improvement" was noted in patients that underwent fat grafting alone. The difference between skin quality and volume improvement scores was found to be significantly in favor of the patients that received adjunctive microneedling. Conclusion: Fat grafting to the face with adjunctive microneedling is a practical and potentially mutual-acting technique that can be used both for its significant effect on increasing fat graft survival and improving skin quality.

The effect of low-dose methotrexate on autologous fat graft survival.

BACKGROUND/AIM: The survival of autologous fat graft tissue is dependent on various factors such as vascularization and inflammation. The aim of the present study was to evaluate the possible beneficial effects of low-dose methotrexate (LD-MTX) on fat graft volume and survival. MATERIALS AND METHODS: A total of 13 male Wistar albino rats were divided into two groups, a control group and an LD-MTX group. An autologous fat graft obtained from the inguinal region of each rat was transferred to its back. LD-MTX was administered intraperitoneally in the LD-MTX group once a week for 4 weeks after the surgical procedure. The control group underwent surgery but was not administered MTX. Fat grafts were harvested for analyses. RESULTS: The results showed that 2 months postoperatively the fat graft weights of the control and LD-MTX groups were not significantly different. In addition, the vascularity of the grafts was higher in the LD-MTX group than it was in the control group. The mean lipid peroxidation levels were essentially the same in the two groups, but myeloperoxidation was significantly lower in the LD-MTX group than it was in the other group. CONCLUSION: The results showed that LD-MTX administration may not preserve the quality and volume of transplanted fat tissue in rats.

The effects of the centrifugation speed on the survival of autogenous fat grafts in a rat model.

Purpose The most important problem in fat transplantation is the durability, which is closely associated with the applied technique. This study includes the comparison of different centrifugation speeds on the survival of autogenous fat grafts in rats. Materials and methods Forty-nine Sprague-Dawley rats were divided into seven groups and the left inguinal fat pad was extracted and re-implanted under the scalp after performing appropriate preparation processes. In the first group the fatty tissue was re-implanted in en-bloc fashion and in the second group it was re-implanted after trimming. After trimming, centrifugation with a G-force of 111.8 (1000 rpm) was performed in the third group, 447.2 (2000 rpm) in the fourth group, 1006.2 (3000 rpm) in the fifth group, 1788.8 (4000 rpm) in the sixth group, and 2795 (5000 rpm) in the seventh group for 4 minutes. The fat grafts were taken after 3 months and histopathological and statistical evaluations were performed. Results The rate of viable fat grafts was significantly higher in the 4th and 5th groups comparing to the first three groups. Total weight and volume amounts of the 4th and 5th groups were also significantly higher comparing to the first three groups. Conclusion Maximal long-term durability and fat cell viability results were obtained in the groups with 2000 rpm or 447.2 G-force/4 minutes and 3000 rpm or 1006.2 G-force/4 minutes centrifugation speed, indicating that 4 minutes centrifugation with an average G-force of 698.75 or 2500 rpm provides the best results for the survival of autogenous fat grafts.

Improving fat graft survival through preconditioning of the recipient site with microneedling.

Although fat grafts are considered the ideal soft-tissue fillers, the main concern dealing with this technique is not being able to predict long-term graft survival due to high absorption rates. The purpose of this study was to investigate the angiogenic effects of preconditioning the recipient area with micro-needling and to determine its overall impact on fat graft survival. The study consisted of a sham, control and study group. The source of fat was the Wistar albino rat inguinal fat pad while the recipient area was a dorsal subcutaneous pouch. The dorsal area was preconditioned with standard technique micro-needling 1-week prior to fat graft transfer in the study group while the control group did not undergo micro-needling. At the end of 15 weeks, morphological, biochemical, histological and immunohistochemical evaluation was carried out. Fat grafts in the study group had better integrity and a higher level of vascularity compared to the control group. Volume analysis demonstrated higher graft survival in the study group in comparison to the control group. Histomorphometric and immunohistochemical evaluation showed better graft integrity and uniform adipocytes, less fibrosis, less vacuolisation and inflammation and better vascularisation in the study group. Although higher triglyceride concentrations were measured for the study group, the difference between the two groups was statistically insignificant. In conclusion, fat grafting performed in an area preconditioned with micro-needling results in higher graft volume, better integrity and vascularisation and an overall higher graft survival rate.