Fat Graft Survival Research Articles

The Potential Role of Exosomes in Aesthetic Plastic Surgery: A Review of Current Literature.

A literature review was performed using PubMed with keywords exosomes, secretomes, extracellular vesicles, plastic surgery, skin rejuvenation, scar revision, hair growth, body contouring, and breast augmentation. Publications from 2010 to 2021 were analyzed for relevance and level of evidence. A Google search identified exosome distributors, where manufacturing/procurement details, price, efficacy, and clinical indications for use were obtained by direct contact and summarized in table format. Exosomes are currently derived from bone marrow, placental, adipose, and umbilical cord tissue. Laboratory-based exosome studies demonstrate enhanced outcomes in skin rejuvenation, scar revision, hair restoration, and fat graft survival on the macro and micro levels. Clinical studies are limited to anecdotal results. Prices vary considerably from $60 to nearly $5000 based on company, source tissue, and exosome concentration. No exosome-based products are currently Food and Drug Administration-approved. Administered alone or as an adjunct, current reports show promise in several areas of aesthetic plastic surgery. However, ongoing investigation is warranted to further delineate concentration, application, safety profile, and overall outcome efficacy.

MiR-24-3p regulates the differentiation of adipose-derived stem cells toward pericytes and promotes fat grafting vascularization.

Adipose-derived stem cells (ADSCs) enhance fat graft survival by promoting neovascularization. The mechanism that promotes ADSCs differentiation toward pericytes was not known. We treated ADSCs with conditional medium (CM) from endothelial cells (ECs) or human recombinant transforming growth factor β (TGF-β) to induce differentiation into pericytes. Pericytes markers, including platelet-derived growth factor receptor β (PDGFRβ), alpha-smooth muscle actin (α-SMA), and desmin, were examined. Pericytes differentiation markers, migration, and their association with ECs were examined in ADSCs transfected with miR-24-3p mimics and inhibitors. Bioinformatics target prediction platforms and luciferase assays were used to investigate whether PDGFRβ was directly targeted by miR-24-3p. In vivo, fat mixed with ADSCs transfected with miR-24-3p mimics or inhibitors was implanted subcutaneously on the lower back region of nude mice. Fat grafts were harvested and analyzed at 2, 4, 6, and 8 weeks. Results showed that endogenous TGF-β derived from CM from EC or human recombinant TGF-β promoted migration, association with ECs, and induced expression of pericyte markers (PDGFRβ, α-SMA, Desmin) in ADSCs. MiR-24-3p directly targeted PDGFRβ in ADSCs by lucifer reporter assays. Inhibition of miR-24-3p promoted pericytes differentiation, migration, and association with ECs in ADSCs. Inhibition of miR-24-3p in ADSCs promoted survival, integrity, adipocyte viability, vascularization, pericytes association with ECs, and reduced fibrosis, whereas overexpression of miR-24-3p in ADSCs yielded the opposite results. Collectively, TGF-β released by ECs induced ADSCs differentiation toward pericytes through miR-24-3p. Downregulation of miR-24-3p in ADSCs induced survival, integrity, adipocyte viability, vascularization, pericytes association with ECs, and reduced fibrosis after fat grafting.

Fat graft survival requires metabolic reprogramming toward the glycolytic pathway

Fat grafts are widely used as natural fillers in reconstructive and cosmetic surgery. However, the mechanisms underlying fat graft survival are poorly understood. Here, we performed an unbiased transcriptomic analysis in a mouse fat graft model to determine the molecular mechanism underlying free fat graft survival. We conducted RNA-sequencing (RNA-seq) analysis in a mousefree subcutaneous fat graft model on days 3 and 7 following grafting (n = 5). High-throughput sequencing was performed on paired-end reads using NovaSeq6000. The calculated transcripts per million (TPM) values were processed for principal component analysis (PCA), unsupervised hierarchically clustered heatmap generation, and gene set enrichment analysis. PCA and heatmap data revealed global differences in the transcriptomes of the fat graft model and the non-grafted control. The top meaningful upregulated gene sets in the fat graft model were related to the epithelial-mesenchymal transition, hypoxia on day 3, and angiogenesis on day 7. Mechanistically, the glycolytic pathway was upregulated in the fat graft model at days 3 (FDR q = 0.012) and 7 (FDR q = 0.084). In subsequent experiments, pharmacological inhibition of the glycolytic pathway in mouse fat grafts with 2-deoxy-D-glucose (2-DG) significantly suppressed fat graft retention rates, both grossly and microscopically (n = 5). Free adipose tissue grafts undergo metabolic reprogramming toward the glycolytic pathway. Future studies should examine whether targeting this pathway can enhance the graft survival rate.

Evaluation of the Effect of Metoprolol Dosage on Fat Graft Survival.

The aim of this study was to evaluate the effect of different metoprolol doses on fat graft survival. A total of 10 Sprague-Dawley rats were used in the study. The dorsal regions of the rats were separated into four quadrants: right and left cranial, and right and left caudal. Each quadrant was determined as a separate group. Fat grafts were harvested from the groin areas and incubated in 5ml solutions containing 0.9% sodium chloride (control group), 1mg/mL metoprolol (Group 1), 2mg/mL metoprolol (Group 2), and 3mg/mL metoprolol (Group 3), respectively. The fat grafts were then placed in pockets dissected in each of the 4 dorsal quadrants. After 3 months all the rats were euthanized. The fat grafts were removed together with the surrounding area to which they had passed. Histopathological examination was made with hematoxylin and eosin (HE) and Masson Trichrome staining, and immunohistochemical examination with fibroblast growth factor-2 and perilipin staining. In the examinations made with HE and Masson Trichrome staining, the scores of Group 2 and Group 3 were determined to be significantly higher than those of the control group (p<0.05). The Group 3 scores were significantly higher than those of Group 1 (p<0.05). In the examinations made with fibroblast growth factor-2 staining, the scores of Group 2 and Group 3 were determined to be significantly higher than those of the control group (p<0.05). The Group 3 scores were significantly higher than those of Group 1 and Group 2 (p<0.05). In the examinations made with perilipin staining, the scores in Groups 1, 2, and 3 were higher than those of the control group (p<0.05). Although metoprolol has previously been shown to prolong the survival of fat grafts, the results of this study demonstrated immunohistochemically that as the metoprolol dose increased, so the quality and vitality of fat graft also increased. 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 .

Astaxanthin Promotes the Survival of Adipose-Derived Stem Cells by Alleviating Oxidative Stress via Activating the Nrf2 Signaling Pathway.

The survival of free fat grafts is dependent primarily on adipose-derived stem cells (ADSCs); however, ADSCs are susceptible to oxidative stress in the recipient area. Astaxanthin (Axt) is a natural xanthophyll carotenoid with potent antioxidant properties and numerous clinical applications. To date, the therapeutic potential of Axt in fat grafting has not been explored. The purpose of this study is to investigate the effects of Axt on oxidatively stressed ADSCs. An oxidative model of ADSCs was developed to simulate the host's microenvironment. Oxidative insult decreased the protein levels of Cyclin D1, type I collagen alpha 1 (COL1A1), and type II collagen alpha 1 (COL2A1), while increasing the expression of cleaved Caspase 3 and secretion of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) in ADSCs. Axt pre-treatment significantly reduced oxidative stress, increased the synthesis of an adipose extracellular matrix, alleviated inflammation, and restored the impaired adipogenic potential in the present model. Furthermore, Axt immensely activated the NF-E2-related factor 2 (Nrf2) pathway, and ML385, an inhibitor of Nrf2, could negate Axt's protective effects. Additionally, Axt alleviated apoptosis by inhibiting bcl-2-associated X protein (BAX)/Caspase 3 signaling and improving the mitochondrial membrane potential (MMP), which could also be abolished by ML385. Our results suggest that Axt may exert its cytoprotective effect on ADSCs through the Nrf2 signaling pathway and could be therapeutic in fat grafting.

Analysis of Fat Graft Survival and Platelet-Rich Plasma Effects: The Transcriptomic Differences.

Fat graft survival has been studied numerously but has not gone beyond hypothetical solutions. The molecular changes in survival of standard fat grafts and enhanced survival by platelet-rich plasma (PRP) are compared in this study to reveal the etiology that causes the loss of fat grafts after transplantation. A New Zealand rabbit's inguinal fat pads were excised and divided into three groups: Sham, Control (C), and PRP. Each weighing 1 g, C and PRP fat were placed into the bilateral parascapular area of the rabbit. After 30 days, the remaining fat grafts were harvested and weighed (C = 0.7 g, PRP = 0.9 g). All three specimens were put into transcriptome analysis. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes Analysis were done to compare the genetic pathways between the specimens. Transcriptome analysis showed similar differential expressions in Sham vs. PRP and Sham vs. C comparisons, indicating the dominance of the cellular immune response in both C and PRP specimens. C and PRP comparison resulted in inhibited migration and inflammation pathways in PRP. Fat graft survival is more related to immune responses than any other physiological process. PRP enhances survival by attenuating cellular immune reactions.

Monocyte Chemoattractant Protein-1-Supplemented Plasma Enhances Adiponectin and Adipogenesis-Related Gene Expression.

Increasing adipogenesis has been explored to treat metabolic diseases and atherosclerosis through the release of adiponectin. The effects and mechanism of platelet-rich plasma treatment on fat graft survival and adipogenesis have not been clarified. Here, we aimed to study the effects of monocyte chemoattractant protein-1 (MCP-1)-supplemented plasma on adipogenesis-related gene expression and adiponectin levels. Stromal vascular fractions (SVFs) purified from the inguinal adipose tissue of obese and diabetic (Leprdb/db) mice were treated with plasma from control (Lepr+/+) mice supplemented with 10 or 50 ng of MCP-1. The expression of adiponectin and interleukin-33 (IL-33) mRNA in adipose tissue was increased in Leprdb/db mice, whereas control (Lepr+/+) plasma reduced expression of IL-33 mRNA as well as peroxisome proliferator-activated receptor gamma (PPARγ), pJNK, and pNF-κB protein, and increased the expression of IL-10 mRNA in SVFs of Leprdb/db mice. MCP-1-supplemented control plasma increased the expression of adiponectin, CCAAT-enhancer-binding protein α (C/EBPα), dipeptidyl peptidase 4 (DPP4), IL-33, and PDGFα mRNA and the expression of adiponectin protein as well as PPARγ of SVFs and the expression of PPARγ mRNA in adipose tissue macrophages (ATMs). Injection of MCP-1-supplemented plasma into adipose tissue of Leprdb/db mice increased the expression of IL-33 and Col3a1 mRNA in SVFs and IL-33, FABP4, PDGFα, PPARγ and PPARγ2 of ATMs, protein expression of adiponectin and PPARγ of SVFs, and plasma adiponectin levels, as well as DPP4 activity. In conclusion, our results demonstrate that control plasma decreases adipogenesis and increases IL-10, and decreases IL-33, pJNK, and pNF-κB in adipose tissue. MCP-1-supplemented plasma enhances adipogenesis-related gene expression in SVFs and adiponectin levels, which may be mediated through an increase of IL-33 and PPARγ. Thus, our findings suggest that MCP-1-supplemented plasma represents a novel therapy to stimulate local adipogenesis and systemic adiponectin levels.

Retracted: Hyperbaric Oxygen Improves the Survival and Angiogenesis of Fat Grafts after Autologous Fat Transplantation.

[This retracts the article DOI: 10.1155/2022/6738959.].

Stem cells in plastic surgery and aesthetic medicine.

Stem cells (SCs) have multiple applications in today's medicine including aesthetic dermatology and plastic surgery. The purpose of this paper is to review some clinical use of mesenchymal SCs. The main focus was put on adipose tissue-derived stem cells (ADSCs) as these cells are easy to harvest and because of their properties showed great potential in many studies, where they proved to accelerate wound healing, reduce scars, cause hair regrowth, or rejuvenate skin. Furthermore, when added to lipofilling procedures, such as breast augmentation they enhance fat graft survival and provide satisfying results. Currently, many different strategies for using SCs in treatments are developed with great efficacy, however, there are still many limitations and concerns regarding their clinical use.

Stages of preadipocyte differentiation: biomarkers and pathways for extracellular structural remodeling

BackgroundThis study utilized bioinformatics to analyze the underlying biological mechanisms involved in adipogenic differentiation, synthesis of the extracellular matrix (ECM), and angiogenesis during preadipocyte differentiation in human Simpson–Golabi–Behmel syndrome at different time points and identify targets that can potentially improve fat graft survival.ResultsWe analyzed two expression profiles from the Gene Expression Omnibus and identified differentially expressed genes (DEGs) at six different time points after the initiation of preadipocyte differentiation. Related pathways were identified using Gene Ontology/Kyoto Encyclopedia of Genes and Genomes analyses and Gene Set Enrichment Analysis (GSEA). We further constructed a protein–protein interaction (PPI) network and its central genes. The results showed that upregulated DEGs were involved in cell differentiation, lipid metabolism, and other cellular activities, while downregulated DEGs were associated with angiogenesis and development, ECM tissue synthesis, and intercellular and intertissue adhesion. GSEA provided a more comprehensive basis, including participation in and positive regulation of key pathways of cell metabolic differentiation, such as the “peroxisome proliferator-activated receptor signaling pathway” and the “adenylate-activated protein kinase signaling pathway,” a key pathway that negatively regulates pro-angiogenic development, ECM synthesis, and adhesion.ConclusionsWe identified the top 20 hub genes in the PPI network, including genes involved in cell differentiation, ECM synthesis, and angiogenesis development, providing potential targets to improve the long-term survival rate of fat grafts. Additionally, we identified drugs that may interact with these targets to potentially improve fat graft survival.

The Effect of Centrifuge Duration on Fat Graft Survival.

Background Although fat grafts are widely used for reconstruction and aesthetic purposes, their survival rates differ significantly. Centrifugation is one of the methods used to increase the survival of fat grafts. However, experimental studies examining the long-term outcomes of centrifugation duration are currently limited. Thus, in the present study, the effects of centrifugation duration on the survival of fat grafts were assessed using an animal model. Methods Thirty Sprague Dawley rats were included in the study and fat grafts were obtained from each specimen by excision from inguinal fat pads. Preparation protocols were administered as an en-bloc fat graft in Group 1, minced fat graft in Group 2, and fat graft centrifuged at 1,054 ×g for 2 minutes, 3 minutes, and 4 minutes in Group 3, 4, and 5, respectively. After 12 weeks of follow-up, grafts were harvested and were subjected to histopathological evaluation based on an established scoring system. Results En-block fat grafts were associated with necrosis, fibrosis, inflammation, vacuole formation, and alterations in adipocyte morphology. Among the three centrifugation groups, Group 3 demonstrated the best adipocyte viability and vascularity. However, graft weights decreased in all experimental groups. Conclusion The centrifugation process may have positive effects on adipocyte survival by means of purifying the fat graft and increasing adipocyte concentration. When the centrifugal durations were compared, 3-minute centrifuge yielded the most favorable results.

Salvianolic Acid B Reduces the Inflammation of Fat Grafts by Inhibiting the NF-Kb Signalling Pathway in Macrophages.

Autologous fat grafting is a common method for soft tissue defect repair. However, the high absorption rate of transplanted fat is currently a bottleneck in the process. Excessive inflammation is one of the main reasons for poor fat transplantation. Salvianolic acid B (Sal-B) is a herbal medicine that shows promise for improving the effectiveness of fat transplantation. The aim of this study was to improve fat graft survival by injecting Sal-B into fat grafts locally. In vivo, 0.2 mL of Coleman fat was transplanted into nude mice along with Sal-B. The grafts were evaluated by histologic analysis at 2, 4, and 12 weeks posttransplantation and by microcomputed tomography at 4 weeks posttransplantation. In vitro ribonucleic acid sequencing, cell proliferation assays, anti-inflammatory activity assays, molecular docking studies, and kinase activity assays were performed in RAW264.7 cells to detect the potential mechanism. Sal-B significantly improved fat graft survival and attenuated adipose tissue fibrosis and inflammation. Sal-B also inhibited the polarization of M1 macrophages in fat grafts. In vitro, Sal-B inhibited the proliferation and activation of inflammatory pathways in RAW264.7 cells. In addition, Sal-B had an inhibitory effect on NF-κB (nuclear factor κ light polypeptide gene enhancer in B cells) signaling. This bioactivity of Sal-B may result from its selective binding to the kinase domain of the inhibitor of NF-κB kinase subunit β. Sal-B could serve as a promising agent for improving the effect of fat transplantation by inhibiting the polarization of M1 macrophages through NF-κB signaling.

Increased Fat Graft Survival by Promoting Adipocyte Dedifferentiation.

Some adipocytes undergo dedifferentiation after fat transplantation, and this may affect the survival of fat grafts. However, this effect has not been adequately studied. This study aimed to clarify the effect of promoting the dedifferentiation of mature adipocytes on the survival of fat grafts. 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. 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. This study suggests that promoting the dedifferentiation of mature adipocytes can improve the survival rate and quality of fat grafts.

Fat Grafting Practices and Preferences, Are We Any Closer to a Standardized Approach? A Survey Providing Insights on Current Trends in Small and Large Fat Grafting

INTRODUCTION: Fat grafting has revolutionized plastic surgery practices since Coleman brought it to the frontline in 1995, and it is now used in a variety of areas ranging from breast reconstruction to regenerative medicine. However, due to a lack of evidence-based studies, multicenter, prospective, and/or randomized trials, we still don’t recognize which variables influence fat grafting’s positive clinical outcomes. METHODS: Following International Society of Plastic Regenerative Surgeons (ISPRES) Board approval, a 30-item questionnaire online survey was designed for distribution to a randomized cohort of ISPRES members) from 2nd July to 16th July 2021, participation in the survey was voluntary and participants could exit the survey without submitting their responses at any time. No participant compensation was provided. The questionnaire was designed to delineate in addition to demographic information, experience, practices, and beliefs among surgeons with regard to the use of autologous fat for contour restoration. RESULTS: The survey was completed by 62 ISPRES members, with 93.5% of the participants having Plastic Surgery Board Certification Status. The mean age of the surveyed members was 53 (9.7). The majority of the members (69.4%) work predominantly in aesthetic plastic surgery. Experience with Large-volume Fat Grafting Donor Site Selection The most commonly used donor area selection criteria were based on the patient’s fat availability (59.7 percent). In addition, 35.5 percent said they preferred to go directly to the abdomen, and only three (4.8 percent) said the patients chose the donor area. Nevertheless, when asked which zones they prefer to remove fat, when possible, abdomen (88.7%) was the commonest site, followed by flanks (62.9 percent). Fat Grafting Harvesting Infiltration Solution, Harvesting Instrument and Technique The most common infiltration solutions used in high volume fat transfers are the 3: 1 ratio tumescent solution (41.9 percent), secondly the super wet solution (40.3 percent) and thirdly the wet solution {100-300 ml of liquid (with or without epinephrine) at each site to be treated} (14.5 percent). Most respondents chose multiple options for the preferred cannula size, tip, holes and method used for fat harvest. The most common instrument preferred for large-volume fat harvesting amongst the respondents are 3-4mm cannulas (69.5 percent). Respondents’ preference of type of cannula tip and holes for fat harvest in large-volume procedures were the three-hole standard cannulas. Handheld suction (59.7 percent) was the most preferred fat harvest method followed by vacuum machine suction (46.8 percent.) Fat Graft Processing Following fat harvest, 56.5 percent (n=35) respondents (without exclusivity) performed decantation of fat, 43.5 percent performed centrifugation. Routine addition of PRP (platelet-rich-plasma) and adipose stem cells have been reported by 12.9 percent and 9.7 percent respondents respectively. Furthermore, 13 respondents report employing additional processing steps to isolate, prepare and store adipose stem cells. Fat Injection For handheld injections (without exclusivity), respondents prefer 1-2mm cannula with 1cc syringe (58.1 percent), closely followed by 1-2mm cannula with 10cc syringe (56.4 percent). Assessment of Outcome Preoperative and postoperative picture evaluation (59.6 percent) and clinical assessment (20.9 percent) were the most commonly used for assessment of fat graft survival by respondents. Only 14.5 percent of participants use preoperative and postoperative 3D images to evaluate. Fat Transfer in Cosmetic Breast Augmentation and Application of Pre-expansion Devices for Breast Augmentation The most commonly preferred plane for fat injection in cosmetic breast augmentation were gland and subcutaneous tissue. Only 8.1 percent (n=5) respondents routinely use pre-expansion devices for breast augmentation before fat grafting. Experience with Small-volume Fat Grafting The majority (53.3 percent) of the responders performed none or less than 25 percent of the small volume fat grafts under general anesthesia. Although there are almost 29 percent of surgeons who apply general anesthesia in 50 percent or more of them, being that 8 percent of them perform almost all surgeries with general anesthesia. CONCLUSION: Evidence-based studies incorporating randomized controlled, prospective, multicenter trials are imperative to understand which variables influence positive fat grafting clinical outcomes. Our research shows preliminary findings analyzing the current practices and preferences of the ISPRES community. The respondents’ tendencies were similar to previous literature, with some exceptions, such as the technique for preparing fat and enrichment, as well as the disparity in responses in the use of cannulas. A cross-sectional survey study of a wider scope, involving national delegates and global representatives of plastic surgeons is anticipated.

Cell-Enriched Lipotransfer (CELT) Improves Tissue Regeneration and Rejuvenation without Substantial Manipulation of the Adipose Tissue Graft.

The good availability and the large content of adult stem cells in adipose tissue has made it one of the most interesting tissues in regenerative medicine. Although lipofilling is one of the most frequent procedures in plastic surgery, the method still struggles with high absorption rates and volume losses of up to 70%. Therefore, many efforts have been made to optimize liposuction and to process the harvested tissue in order to increase fat graft retention. Because of their immunomodulatory properties, their cytokine secretory activity, and their differentiation potential, enrichment with adipose tissue-derived stem cells was identified as a promising tool to promote transplant survival. Here, we review the important parameters for lipofilling optimization. Finally, we present a new method for the enrichment of lipoaspirate with adipose tissue-derived stem cells and discuss the parameters that contribute to fat graft survival.

Xenogenic induction of adipose tissue and maintenance through pre- and post-conditioning using external volume expansion

External volume expansion (EVE) has been shown to improve fat graft survival. In this study, we investigated the xenogenic implantation of human allograft adipose matrix (AAM) in non-immunocompromised mice in combination with pre- and post-conditioning with EVE to assess long-term adipose tissue survival. Sixty-eight recipient sites in thirty-four eight-week-old wild type (C57BL/6J) mice were separated into four groups. Thirty-four sites received no conditioning and either a subcutaneous injection of 300 μl saline (n = 17; PBS group) or AAM (n = 17; AAM group). Thirty-four sites received pre-conditioning with EVE (Day -7–3 pre-grafting) and 300 μl of AAM. Seventeen of these sites received immediate post-conditioning (Day 1–5 post-grafting) and 17 delayed post-conditioning (Day 28–32 post-grafting). Tissue was harvested at week 12 for analysis. At 12 weeks, immediate and delayed post-conditioning enabled higher volume retention (p = 0.02 and p < 0.0001, respectively). Adipose Stem Cells were greater in the AAM+Del-EVE group compared to the AAM (p = 0.01). Microvessel density was lower in the AAM group compared to the AAM+Imm-EVE (p = 0.04) and AAM+Del-EVE group (p = 0.02). Macrophage infiltration was lower in the AAM+Imm-EVE (p = 0.002) and AAM+Del-EVE (p = 0.003) groups compared to the AAM group. PCR analysis and Western blotting identified a significantly higher expression of PPAR-γ, LPL and VEGF with delayed-conditioning. Pre- and post-conditioning, particularly delayed-post-conditioning, of the recipient site optimized the microenvironment allowing significant adipogenesis and survival of neo-adipose tissue through robust angiogenesis. This study supports that xenogenic transplantation of adipose matrix allows adipose tissue formation and survival with EVE as an adjuvant.

Mechanical Stress Improves Fat Graft Survival by Promoting Adipose-Derived Stem Cells Proliferation.

Cell-assisted lipotransfer (CAL), defined as co-transplantation of aspirated fat with enrichment of adipose-derived stem cells (ASCs), is a novel technique for cosmetic and reconstructive surgery to overcome the low survival rate of traditional fat grafting. However, clinically approved techniques for increasing the potency of ASCs in CAL have not been developed yet. As a more clinically applicable method, we used mechanical stress to reinforce the potency of ASCs. Mechanical stress was applied to the inguinal fat pad by needling. Morphological and cellular changes in adipose tissues were examined by flow cytometric analysis 1, 3, 5, and 7 days after the procedure. The proliferation and adipogenesis potencies of ASCs were evaluated. CAL with ASCs treated with mechanical stress or sham control were performed, and engraftment was determined at 4 weeks post-operation. Flow cytometry analysis revealed that mechanical stress significantly increased the number as well as the frequency of ASC proliferation in fat. Proliferation assays and adipocyte-specific marker gene analysis revealed that mechanical stress promoted proliferation potential but did not affect the differentiation capacity of ASCs. Moreover, CAL with cells derived from mechanical stress-treated fat increased the engraftment. Our results indicate that mechanical stress may be a simple method for improving the efficacy of CAL by enhancing the proliferation potency of ASCs.

Effects of miR126 Expressing Adipose-Derived Stem Cells on Fat Graft Survival and Angiogenesis.

Fat transplantation supported by supplementation with ASCs has become a reliable procedure for treating soft tissue defects. However, the unpredictable survival rates for grafted fat remains a challenge with post-transplantation ischemia causing tissue loss. MiR126, which regulates VEGF signaling, is an endothelial cell-specific miRNA known to play an essential role in angiogenesis. We hypothesized that increased miR126 expression in grafted ASCs may promote fat survival within an autologous fat transfer model. Rat adipose-derived stem cells were isolated, expanded ex vivo for three passages and then transduced with miR126. We used PCR to verify lentiviral transduction and ELISA to confirm VEGF expression. We then mixed autologous fat tissues from our rat model with transduced ASCs, augmented with a nonsense control or miR126 expression vector. These mixtures were used in the fat grafting procedure, completed via subcutaneous injection at three paravertebral points in each rat. Fat grafts were then harvested on days 4, 7, 14, and 28 post-transplant and evaluated for survival, neovascularization, and protein expression via western blot. VEGF expression levels in ASCs, Con-ASCs, and miR126-ASCs were not significantly different. However, miR126-ASCs experienced significantly improved survival on days 7, 14, and 28 when compared with the other groups. These ASCs also presented with the greatest capillary density on days 7, 14, and 28 post-transplantation as well as increased p-ERK and p-AKT expression when compared to the other groups. This data suggests that miR126 augmentation of ASCs may help to enhance the survival and angiogenic capacity of transplanted fat tissues, and that this augmentation was not dependent on VEGF but rather the activation of the ERK/AKT pathway. 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 .

The fates of different types of adipose tissue after transplantation in mice.

Fat grafting is one of the most commonly applied procedure for soft-tissue repair. However, it remains unclear whether the type of adipose tissue would have any effects on fat graft survival. The present study aimed to determine fates of fat grafting of three different types of fat tissue. In this study, mice were randomly divided into three groups, white adipose tissue (WAT) group, beige adipose tissue (beige AT) group and brown adipose tissue (BAT) group. Before transplantation, donor mice were injected with rosiglitazone or phosphate-buffered saline (PBS). The WAT and BAT were obtained from PBS-treated mice while beige AT was obtained from the rosiglitazone-treated mice. Three types of fat tissue (150 mg each) were transplanted in three groups, respectively, and harvested at 2, 4 or 12 weeks. The BAT and beige AT contained smaller adipocytes and expressed higher level of uncoupling protein-1 gene. The retention rate of the transplanted fat was significantly higher for beige than for white fat, but was significantly lower for brown than for white fat. Transplanted brown fat was characterized by upregulated inflammation and high endoplasmic reticulum stress. By contrast, fat grafts in beige AT group showed the best adipogenic capacity, moderate inflammation level and superior angiongenesis. In vitro, under hypoxic condition, fewer apoptotic cells were found in beige adipocyte group than that in brown and white adipocyte group. Conditioned medium from brown adipocytes induced M1 polarization of RAW 264.7 macrophages while that from beige adipocytes effectively promoted M2 polarization. Therefore, we suggest that beige AT provides a new potential choice for fat grafting because of low inflammation and superior survival but BAT might not be ideal for fat grafting due to its poor survival.

Retropectoral Fat Graft Survival in Mammoplasty: Evaluation by Magnetic Resonance Imaging.

Fat grafting is used in combination with mammoplasty to improve filling of the upper pole of the breasts. Its effectiveness remains in question due to unpredictable results. Difficulty in isolating the grafted fat and differentiating it from host tissues may hinder assessment of graft integration. The plane between the pectoral muscles is free of fat and has already been described with respect to placement of breast implants and fat grafting in breast surgeries. This study sought to evaluate via magnetic resonance imaging (MRI) the integration and retention of retropectoral fat grafts in mammoplasty. Thirty patients with breast flaccidity who desired to undergo mammoplasty were selected. Fat collected from the abdomen was separated by sedimentation and transferred to the retropectoral region after undermining of the breast and resection of excess tissue. The patients underwent MRI preoperatively and at three and six months after surgery. Fat volumes were calculated by multiplying the values for the major vertical, horizontal, and anteroposterior axes by the constant 0.523. Twenty-five patients completed the study. The mean volume grafted was 116.4 ± 22.5 ml per breast. Six months after surgery, the mean fat graft volume in the retropectoral plane was 48.1 ± 25.71 ml, and the integration rate was 40.82% (range, 32.2-49.4%). The rate of complications related to fat grafting was 8%. In mammoplasty, retropectoral fat grafting showed good integration rates and is a safe and predictable approach that can contribute to improving the outcomes of aesthetic and reconstructive breast surgeries. 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 .