Improve Fat Graft Survival Research Articles

Fat extract improves fat graft survival via proangiogenic, anti-apoptotic and pro-proliferative activities

BackgroundOur previous study proved that nanofat could enhance fat graft survival by promoting neovascularization. Fat extract (FE), a cell-free component derived from nanofat, also possesses proangiogenic activity.ObjectivesThe aim of this study was to investigate whether FE could improve fat graft survival and whether FE and nanofat could work synergistically to promote fat graft survival. The underlying mechanism was also investigated.MethodsIn the first animal study, human macrofat from lipoaspirate was co-transplanted into nude mice with FE or nanofat. The grafts were evaluated at 2, 4 and 12 weeks post-transplantation. In the second animal study, nude mice were transplanted with a mixture of macrofat and nanofat, followed by intra-graft injection of FE at days 1, 7, 14, 21 and 28 post-transplantation. The grafts were evaluated at 12 weeks post-transplantation. To detect the mechanism by which FE impacts graft survival, the proangiogenic, anti-apoptotic and pro-proliferative activities of FE were analysed in grafts in vivo and in cultured human vascular endothelial cells (HUVECs), adipose-derived stem cells (ADSCs) and fat tissue in vitro.ResultsIn the first animal study, the weights of the fat grafts in the nanofat- and FE-treated groups were significantly higher than those of the fat grafts in the control group. In addition, higher fat integrity, more viable adipocytes, more CD31-positive blood vessels, fewer apoptotic cells and more Ki67-positive proliferating cells were observed in the nanofat- and FE-treated groups. In the second animal study, the weights of the fat grafts in the nanofat+FE group were significantly higher than those of the fat grafts in the control group. In vitro, FE showed proangiogenic effects on HUVECs, anti-apoptotic effects on fat tissue cultured under hypoxic conditions and an ability to promote ADSC proliferation and maintain their multiple differentiation capacity.ConclusionsFE could improve fat graft survival via proangiogenic, anti-apoptotic and pro-proliferative effects on ADSCs. FE plus nanofat-assisted fat grafting is a new strategy that could potentially be used in clinical applications.

Local Subcutaneous Injection of Erythropoietin Might Improve Fat Graft Survival, Whereas Continuous Infusion Using an Osmotic Pump Device Was Harmful by Provoking an Overwhelming Foreign Body Reaction in a Nude Mouse Model

Local Subcutaneous Injection of Erythropoietin Might Improve Fat Graft Survival, Whereas Continuous Infusion Using an Osmotic Pump Device Was Harmful by Provoking an Overwhelming Foreign Body Reaction in a Nude Mouse Model

Stromal vascular fraction cells plus sustained release VEGF/Ang-1-PLGA microspheres improve fat graft survival in mice.

Autologous fat transplantation is increasingly applied in plastic and reconstructive surgery. Stromal vascular fraction cells (SVFs) combined with angiogenic factors, such as VEGF (vascular endothelial growth factor A) and Ang-1 (angiogenin-1), can improve angiogenesis, which is a critical factor for graft survival. However, direct transplant with such a mixture is insufficient owing to the short half-life of angiogenic factors. In this study, we evaluated whether a double sustained release system of VEGF/ANG-1-PLGA (poly (lactic-co-glycolic acid)) microspheres plus SVFs can improve angiogenesis and graft survival after autologous fat transplantation. VEGF/ANG-1-PLGA-sustained release microspheres were fabricated by a modified double emulsion-solvent evaporation technique. Human aspirated fat was mixed with SVF suspension plus VEGF/ANG-1 sustained release microspheres (Group C), SVF suspension (Group B) alone, or Dulbecco's modified Eagle's medium as the control (Group A). Eighteen immunocompromised nude mice were injected with these three mixtures subcutaneously at random positions. After 8 weeks, the mean volume of grafts was greater in the SVFs plus VEGF/ANG-1-PLGA group than in the control and SVFs groups (1.08 ± 0.069 ml vs. 0.62 ± 0.036 ml, and 0.83 ± 0.059 ml, respectively). Histological assessments showed that lower fibrosis, but greater microvascular density in the SVFs plus VEGF/ANG-1-PLGA group than in the other groups, though the SVFs group also had an appropriate capillary density and reduced fibrosis. Our findings indicate that SVFs plus VEGF/ANG-1-PLGA-sustained release microspheres can improve angiogenesis and graft survival after autologous fat transplantation.

Tamoxifen-Prefabricated Beige Adipose Tissue Improves Fat Graft Survival in Mice.

Fat grafting has become an important tool for breast reconstruction in breast cancer patients. Tamoxifen, the hormone therapy agent most frequently used for breast cancer, can affect adipose metabolism and cause browning of adipose tissue. This study hypothesized that tamoxifen could increase fat graft survival by altering adipose metabolism. C57/BL6 mice were divided into three groups receiving different treatments before and after fat grafting. The tamoxifen/grafting/tamoxifen group was pretreated with daily tamoxifen for 8 weeks, received fat grafting, and was treated with daily tamoxifen. The graft/tamoxifen group was pretreated with daily phosphate-buffered saline for 8 weeks, received fat grafting, and was treated with daily tamoxifen. The control group was pretreated with daily phosphate-buffered saline for 8 weeks, received fat grafting, and was treated with daily phosphate-buffered saline. The inguinal fat used for transplantation and the transferred fat at weeks 4 and 12 after transplantation were harvested and analyzed. Tamoxifen-pretreated inguinal fat showed beige fat features, with smaller adipocyte size, up-regulated uncoupling protein 1 expression, and improved vascularization. The retention rate of transferred fat was significantly higher in the tamoxifen/grafting/tamoxifen group than in the control group (69 ± 12 percent versus 36 ± 13 percent; p < 0.05), but fat grafts in the graft/tamoxifen group had a retention rate similar to that in the control group (31 ± 12 percent versus 36 ± 13 percent; p > 0.05). Improved angiogenesis and increased vascular endothelial growth factor expression were found in the tamoxifen/grafting/tamoxifen group but not in the graft/tamoxifen group. Tamoxifen treatment before fat grafting resulted in prefabricated vascularized beige fat with small adipocytes, which greatly improve fat graft survival. However, tamoxifen after fat grafting did not affect fat graft evolution.

A Systematic Review of Autologous Platelet-Rich Plasma and Fat Graft Preparation Methods.

The addition of platelet-rich plasma (PRP) to adipose tissue may improve fat graft survival, although graft retention rates vary markedly between studies. To what extent this outcome heterogeneity reflects differing methodological factors remains unknown. This systematic review aims to synthesize and critically review methodological approaches to autologous PRP and fat cotransplantation in both human and animal studies. In accordance with PRISMA guidelines, Ovid MEDLINE, Scopus, and Cochrane Library databases were searched from inception to April 2017. Data were extracted from all in vivo studies involving autologous PRP and fat cotransplantation. A secondary aim was to assess reporting of technical detail; authors were not contacted to provide missing data. From 335 articles, 23 studies were included in the qualitative synthesis. Some 21 were performed in humans and 2 in rabbits. Six studies were randomized control trials; the remainder reported on observational data. Methods of PRP extraction and activation varied markedly between studies. Fat graft preparation was comparatively more consistent. Methods of PRP and fat mixing differed significantly, especially with regards to relative volume/volume ratios. Our study represents the first systematic review of methodological factors in autologous PRP and fat cotransplantation. It demonstrates that technical factors in graft preparation and administration vary significantly between in vivo studies. Such methodological heterogeneity may explain observed differences in experimental and clinical outcomes. Reporting of key procedural information is inconsistent and often inadequate. These issues make meaningful evaluation of the PRP-enhanced fat grafting literature difficult and may limit its translation into clinical practice.

Co-Transplantation of Nanofat Enhances Neovascularization and Fat Graft Survival in Nude Mice.

Autologous fat grafting is commonly used for soft-tissue augmentation and reconstruction. However, this technique is limited by a high rate of graft absorption. Thus, approaches to improve fat graft survival that promote neovascularization are of great interest. Nanofat has several beneficial features that may render it more suitable for clinical applications than other stem-cell based approaches. We aimed to determine whether nanofat could enhance new vessel formation and improve the long-term retention of fat grafts. Nanofat was processed via mechanical emulsification and filtration. Fat grafts were transplanted subcutaneously under the scalps of nude mice with different nanofat volumes or without nanofat. The grafted fat was dissected 12 weeks after transplantation. Graft weight and volume were measured, and histological evaluations, including capillary density measurement, were performed. The co-transplantation of fat with nanofat showed higher graft weight and volume retention, better histological structure, and higher capillary density compared to that in controls. However, there were no significant differences between the two nanofat volumes utilized. Nanofat can enhance neovascularization and improve fat graft survival, providing a potential clinically viable approach to fat graft supplementation in plastic and reconstructive surgery.

Low-dose G-CSF improves fat graft retention by mobilizing endogenous stem cells and inducing angiogenesis, whereas high-dose G-CSF inhibits adipogenesis with prolonged inflammation and severe fibrosis

BackgroundHematopoietic stem cells (HSCs) promote fat graft survival by modulating its revascularization. The authors hypothesize that mobilization of HSCs by G-CSF will improve fat graft survival. Hence, we evaluated the effect of different doses of G-CSF on fat grafting. MethodsMale 8-week-old C57 mice received high-dose G-CSF (100 μg/kg), low-dose G-CSF (10 μg/kg), and PBS (control) intraperitoneally for 7 consecutive days right after autologous fat grafting. Grafted fat was harvested at 1, 4, and 12 weeks for examination. ResultsThe low-dose G-CSF, high-dose G-CSF, and control groups had retention rates of 73.6% ± 3.1%, 51.6% ± 4.4%, and 44.5% ± 4.0%, respectively, at 12 weeks (low-dose G-CSF versus control and low-dose G-CSF versus high-dose G-CSF, both p < 0.05; no significant difference between high-dose G-CSF and control group). Both doses of G-CSF successfully mobilized HSCs into circulation and upregulated the level of blood-derived stem cells in fat grafts, contributing to improved angiogenesis. However, high-dose G-CSF caused a prolonged macrophage infiltration and elevated level of inflammation (IL-6 and TNF-α), which led to severe fibrosis and impaired adipogenesis (downregulated expression of PPAR-γ and CEBP-α). ConclusionsLow-dose G-CSF treatment successfully improved fat graft survival by mobilizing HSCs and inducing angiogenesis. However, high-dose G-CSF prolonged inflammation and caused severe fibrosis, leading to impaired adipogenesis and poor fat graft survival.

Abstract 72: Subselected Adipocyte Progenitor Niche Cells Show Superior Incorporation and Function in a Mouse Model

PURPOSE: Previous work from our group has reported that human fat elaborates vascular sprouts when placed in angiogenic media. These vascular sprouts constitute a unique niche for specific cells (Adipocyte Progenitor Niche Cells =APNC) which, when then subjected to adipogenic media, differentiate into adipocytes. This study shows that these subselected adipocytes have superior fat cell function when grafted into a mouse host, as assessed by functional and biochemical parameters that report degree of differentiation and vascularization (levels of human adiponectin in mouse serum and human and mouse PLIN1 and CDH5 mRNA levels in graft). METHODS: Fat excised from a human panniculectomy specimen, was embedded to obtain vascular sprouts. APNCs were extracted, plated and at confluence exposed to control vehicle (APNC_control) or adipogenic cocktail (insulin, dexamethosome and IBMX) for three days (APNC_differentated). After 10 days cells were injected subcutaneously into the flanks of NOD mice. The following groups were compared: 1) APNC_differentated, 2) lipoaspirate from the same specimen, 3) APNC_control and 4) ADSCs prepared from the stromovascular fraction. Grafts were assayed for volume by micro-CT, and functional integration by human serum adiponectin. In addition, immunohistochemistry and RT-PCR for both human and mouse cadherin5 (CDH5, endothelium) and perilipin 1 (PLIN1, adipose) were performed on grafts, and compared to human and mouse adipose tissue samples. RESULTS: Grafts formed from APNC_differentiated produced higher levels of adiponectin per unit volume compared to grafts formed from liposuctioned tissue. Grafts formed from APNC_differentiated were vascularized by host vessels to the same extent as endogenous mouse fat, and contained the same levels of perilipin as human fat. APNC_control, but not ADSCs were able to differentiate in-vivo to a lesser degree, as assessed by detection of human adiponectin in mouse serum. CONCLUSIONS: APNCs may represent more elegant way to retrieve the balanced niche of cells needed for adipocyte tissue engineering. In this pilot work, we show that APNCs produce a superior graft in terms of host incorporation and adipocyte function. Although processing time is an issue, if these cells prove to be more effective than other cells extracted from fat tissue, then they could be used to improve fat graft survival and/or deliver tissue regenerative stimuli in altered wound states. Further work will look to compare APNC_differentiated and APNC_control to the function of SVF and ADSC isolates (important control groups which are already used to ‘supercharge fat grafts) after they have been differentiated through the same media exchanges as APNC_differentiated.

A Simple, Reliable, and Inexpensive Intraoperative External Expansion System for Enhanced Autologous Structural Fat Grafting

External volume expansion of the recipient site by suction has been proposed as a way of improving fat graft survival. The objective of this study was to present an innovative and simple intraoperative external expansion system to enhance small-volume autologous fat grafting (40–80 mL) and to discuss its background and its mechanism of action. In this system, expansion is performed using a complete vacuum delivery system known as the Kiwi VAC-6000M with a PalmPump (Clinical Innovations). The recipient site is rapidly expanded intraoperatively 10 times for 30 seconds each with a negative pressure of up to 550 mm Hg before autologous fat injection. During this repetitive stimulation, the tissues become grossly expanded, developing macroscopic swelling that regresses slowly over the course of hours following the cessation of the stimulus. The system sets various mechanisms in motion, including scar release, mechanical stimulation, edema, ischemia, and inflammation, which provide an environment conducive for cell proliferation and angiogenesis. In order to maintain the graft construct in its expansive state, all patients are encouraged postoperatively to use the Kiwi three times daily for one minute per session over the course of three days. The handling of this system is simple for both the patients and the surgeon. Satisfactory clinical outcomes have been achieved without significant complications.

External Volume Expansion Modulates Vascular Growth and Functional Maturation in a Swine Model.

Despite increasing application of the pre-grafting expansion during autologous fat transplantation in breast reconstruction, little is known about its mechanism of action. To address that, ventral skins of miniature pigs were treated over a 10-day or 21-day period, with continuous suction at −50 mm Hg via a 7-cm diameter rubber-lined suction-cup device. Soft tissue thickness increased immediately after this external volume expansion (EVE) treatment, such increase completely disappeared by the next day. In the dermis and subcutaneous fat, the EVE treated groups showed significant increases in blood vessel density evident by CD31 staining as well as in vascular networks layered with smooth muscle cells when compared with the control group. This finding was corroborated by the increased percentage of endothelial cells present in the treatment groups. There was no significant difference in the percentages of proliferating basal keratinocytes or adipocytes, nor in epidermal thickness. Moreover, the EVE had no effect on proliferation or differentiation potential of adipose stem cells. Taken together, the major effects of EVE appeared to be vascular remodeling and maturation of functional blood vessels. This understanding may help clinicians optimize the vascularity of the recipient bed to further improve fat graft survival.

Efficacy and Safety of Cell-Assisted Lipotransfer: A Systematic Review and Meta-Analysis.

The main drawback of autologous fat grafting, which is commonly used for soft-tissue augmentation, is the high resorption rate. Cell-assisted lipotransfer has been used to improve fat graft survival; however, evidence for its efficacy and safety is still lacking. The authors searched PubMed, Cochrane Library, EBSCO, and EMBASE for clinical studies on cell-assisted lipotransfer published from 2008 through 2014. A meta-analysis was conducted to pool the estimated fat survival rate. Incidence of complications and incidence of multiple operations were calculated. Seventeen articles involving 387 cases were included in the systematic review. The pooled fat survival rate was significantly higher in the cell-assisted lipotransfer group than in the nonlipotransfer group (60 percent versus 45 percent, p = 0.0096). Complication incidence was similar in the two groups. Cell-assisted lipotransfer significantly improved fat survival in the face (by 19 percent) and reduced the incidence of multiple operations (by 13.6 percent). In breast fat grafting, however, fat survival was improved by only 9 percent, which was not statistically significant. Meanwhile, lipotransfer in breast cases was associated with a higher complication incidence compared with face cases (p < 0.001). This study demonstrates that cell-assisted lipotransfer has better efficacy than conventional fat grafting (non-cell-assisted lipotransfer). It is more applicable to face cases than to breast cases. Until now, there has not been enough evidence of the superiority of cell-assisted lipotransfer over conventional fat grafting for reducing complications. Therapeutic, III.

Coimplanted Endothelial Cells Improve Adipose Tissue Grafts’ Survival by Increasing Vascularization

With goal of improving fat graft survival, many studies have focused on supplementing cells in the graft fat. In these studies, enhanced vascularization is considered the most important mechanism for the improved graft survival. Endothelial cells (ECs) are essential in vessel formation of the vascularization. Therefore, in this study, we coimplanted ECs with adipose tissue to investigate whether the ECs can enhance graft survival in a cell concentration-dependent manner. Endothelial cells were isolated from stromal vascular fraction derived from human liposuction aspirates, and the EC characteristics were confirmed by CD31 immunofluorescence staining, measuring acetylated low-density lipoprotein uptake, and observing the formation of capillary-like tubular structures in Matrigel. During the animal experiment, the isolated ECs were labeled, then added to 0.5-mL fat grafts at different numbers (0.5 × 10(6), 1 × 10(6), 2 × 10(6), and 4 × 10(6) cells) before subcutaneous implantation in nude mice. Grafts were harvested at 1 week, 1 month, and 2 months after -transplantation, and graft survival and vascularization were evaluated based on weight measurements, histological assessment, and vascular gene expression. Stromal vascular fraction-derived vascular cells exhibited typical EC characteristics. The observed differences in explanted graft weight, vessel density, vascular gene expression, and cell tracking result indicated that coimplantation with ECs accelerated vascularization that increased graft survival in a concentration-dependent manner. Over the experimental period, fat grafts implanted with 4 × 10(6) ECs showed no weight loss and the greatest increases in measures of vascularization. Endothelial cells can effectively enhance vascularization in fat grafts, and higher EC concentrations (eg, 4 × 10(6) ECs/0.5 mL adipose tissue) may best support graft survival.

Improvement of the survival of human autologous fat transplantation by adipose-derived stem-cells-assisted lipotransfer combined with bFGF.

Adipose-derived stem cells (ASCs) transplanted along with autologous adipose tissue may improve fat graft survival; however, the efficacy of ASCs has been diluted by low vascularization. This study was designed to test the hypothesis that basic fibroblast growth factor (bFGF) may improve the effects of ASCs because it owns the property to boost angiogenesis. In the present study, human fat tissues were mixed with ASCs, ASCs plus 100 U bFGF, or medium as the control and then injected subcutaneously into immunologically compromised nude mice for 12 weeks. Our findings demonstrated that mixture with the ASCs significantly increased the weight and volume of the fat grafts compared to control grafts, and histological analysis revealed that both ASCs and ASCs plus bFGF grafts consisted predominantly of adipose tissue and had significantly less fibrosis but greater microvascular density compared with control and also grafts mixed with ASCs had a high expression of angiogenic factors. More importantly, the bFGF treated fat grafts shown elevate in survival, vascularization, and angiogenic factors expression when compared with the grafts that received ASCs alone. These results indicated that bFGF together with ASCs can enhance the efficacy of autologous fat transplantation and increase blood vessel generation involved in the benefits from bFGF.

N-Acetylcysteine (NAC) Improves Free Autologous Fat Graft Survival

BACKGROUND: Autologous fat grafting is an increasingly popular technique for soft tissue reconstruction, but is limited by inconsistent graft take, under correction, and repeat procedures.1–3 The authors examined whether a widely available, clinically safe anti-oxidant, N-acetylcysteine (NAC), could be added to tumescent solution at time of harvest to improve fat graft survival in a mouse model. METHODS: Inguinal fat grafts were harvested from C57BL/6 mice using tumescent solution with or without NAC, and injected under recipient mouse scalps. Fat graft volumes were evaluated via microCT and Materialise’s Interactive Medical Imaging Control System (MIMICS) volumetric analysis at 4 days (baseline), and 1 and 3 months post-injection. Explanted grafts were weighed and evaluated histologically for vascularity and quality. Flow cytometric analysis (FACS) and MTT assays were performed on adipose-derived stem cells (ADSCs) exposed to oxidative stress (hydrogen peroxide) with and without NAC. The effect of NAC on proliferation of a preadipocyte cell line was also analyzed using Oil Red-O staining and qualitative polymerase chain reaction (qRT-PCR). RESULTS: N-acetylcysteine resulted in improved fat graft retention, with 46% take in NAC animals, compared to 17% in controls (p=0.027) (Figure 1).Figure 1: MIMICS three-dimensional reconstructions of control (left) and NAC (right) mice free fat grafts at 3 months post injection.Explanted grafts from the NAC group were significantly larger (46 vs. 8 milligrams, p<0.01) and had a 133% higher mean adipocyte density on histology (p<0.0001) than controls (Figure 2).Figure 2: Free fat graft weights at 4 days, 1 month, and 3 months of control versus NAC based on three-dimensional reconstructed micro-CT scans of the grafts In Vivo.No increase in vascularity was observed on histology. FACS analysis demonstrated that NAC protected ADSCs from oxidative stress in a dose-dependent manner. Combined exposure to both NAC and hydrogen peroxide led to a 200-fold increase in ADSC proliferation, significantly higher than with either agent alone. NAC significantly decreased the differentiation of pre-adipocyte cells into adipocytes compared to control (p<0.05). CONCLUSIONS: Addition of NAC to tumescent fluid for harvest of fat improves graft survival and quality in a mouse model. Our In Vitro findings suggest that this effect is the result of protection from oxidative stress and increased survival of ADSCs and adipocytes, while keeping the ADSCs in a pre-differentiation state to allow re-population of the graft over time. Thus, NAC is a clinically safe anti-oxidant that could be added to tumescent solution to improve fat graft survival over time, without any subsequent steps or additives ex vivo.

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.

Enhancement of Fat Graft Survival by Bone Marrow–Derived Mesenchymal Stem Cell Therapy

Adipose-derived stem cells can improve fat graft survival, but there is no literature reporting whether bone marrow-derived mesenchymal stem cells enhance fat graft survival. The authors explored the feasibility of enhancing fat graft survival using bone marrow-derived mesenchymal stem cells. Third-passage expanded rabbit bone marrow-derived mesenchymal stem cells were characterized by adipocyte and osteocyte differentiation and by CD29 and CD31 expression. Three were three groups of nude mice in this experiment: group A, mesenchymal stem cells; group B, expanded mesenchymal stem cells; group C, Dulbecco's medium as a blank control. The transplanted mixture contained 0.3 ml of adipose granule and 0.2 ml of cell components of 5×10⁶ cells. Four months later, grafts were harvested, weighed, and analyzed. Expanded cells were successfully isolated and identified by fibroblast-like adherent shape and osteogenic and adipogenic differentiation. The results were 24.6±3.4 percent for CD29 and 1.8±0.4 percent for CD31 in group A, and 45.0±4.9 percent for CD29 and 1.6±0.3 percent for CD31 in group B. Fat graft survival rates were 0.2052±0.0015 g, 0.1761±0.0014 g, and 0.1350±0.0020 g in groups A, B, and C, respectively (p<0.05). Fat grafts in group A exhibited the best survival and morphologic integrity, uniform lipid droplets, and rich blood vessels; those in group B exhibited modest survival, less integrity, less uniform lipid droplets, and connective tissue septa; and those in group C exhibited some large bubbles, varied sizes of lipid droplets, and significant fibrous septa (p<0.05). The vascular densities for groups A, B, and C were 30.4±1.5, 27.2±1.3, and 23.3±1.9 capillaries/mm2, respectively (p<0.05). Bone marrow-derived mesenchymal stem cells and expanded bone marrow-derived mesenchymal stem cells are capable of improving fat graft survival; bone marrow-derived mesenchymal stem cells are more potent than expanded bone marrow-derived mesenchymal stem cells for doing so.

Quantitative volumetric analysis of progressive hemifacial atrophy corrected using stromal vascular fraction-supplemented autologous fat grafts.

Progressive hemifacial atrophy (Parry-Romberg disease) is rare and involves all skin layers and subcutaneous soft and hard tissue. Autologous fat grafting has revolutionized the field of soft-tissue reconstruction and augmentation, but long-term maintenance is unpredictable. Stromal vascular fraction (SVF)-supplemented cell therapy offers new hope for improving fat graft survival, with good long-term results, but efficacy and long-term outcome in the clinic are rarely studied using objective data. To compare the long-term viability of SVF-supplemented fat grafts and fat grafts alone for contour reconstruction of progressive hemifacial atrophy using quantitative volume analysis. We treated 20 patients with stable hemifacial atrophy for at least 2years with SVF-supplemented autologous fat grafting (n=10) or fat grafting alone (n=10). All patients were followed up every 3months. Hemifacial volume was measured using computed tomography and the Philips Extended Brilliance Workspace. All patients had successful outcomes without complications, but fat survival and clinical improvement was greater with SVF-supplemented grafting than fat grafting alone after 6months. SVF-supplemented autologous fat transplantation is effective and safe for treating progressive hemifacial atrophy and can enhance the survival of grafts in the face without major complications.

The Chemokine Stromal Cell–Derived Factor-1α Promotes Endothelial Progenitor Cell–Mediated Neovascularization of Human Transplanted Fat Tissue in Diabetic Immunocompromised Mice

Stromal cell-derived factor-1α is a chemokine and mediates endothelial progenitor cell-induced neovascularization. Because vascularization of a graft is crucial for its survival, the authors investigated whether stromal cell-derived factor-1α could improve fat graft survival by inducing endothelial progenitor cell-mediated neovascularization and preventing its resorption. The authors injected 1 ml of human fat tissue into the scalps of 30 diabetic and 10 nondiabetic immunocompromised mice. The fat grafts were treated with phosphate-buffered saline or stromal cell-derived factor-1α. Determination of graft phenotype included measurements of their weights and volumes, vascular endothelial growth factor (VEGF) levels, the stromal cell-derived factor-1α receptor CXCR4, VEGF receptor 2, endothelial nitric oxide synthase, serine/threonine-specific protein kinase (protein kinase B), caspase 3, and cytochrome c expression levels, and the extent of vascularization. Eighteen days after transplantation, stromal cell-derived factor-1α treatment of the grafts in the diabetic mice (1) increased plasma VEGF levels; (2) raised VEGF receptor 2, CXCR4, endothelial nitric oxide synthase, and protein kinase B expression levels; and (3) reduced caspase 3 and cytochrome c expression levels in the fat grafts. Fifteen weeks after transplantation, stromal cell-derived factor-1α treatment of the grafts prevented their resorption and increased the extent of their vascularization. Locally delivered stromal cell-derived factor-1α increases fat graft survival by stimulating neovascularization and reducing fat cell apoptosis through an endothelial progenitor cell-mediated mechanism.

Stem Cells, Mature Adipocytes, and Extracellular Scaffold: What Does Each Contribute to Fat Graft Survival?

Soft tissue engineering offers new perspectives for improving fat graft survival, for which the appropriate association of cells and scaffold seems essential. This study aimed to analyze the survival of free-cell grafts compared with adipose-derived stem cells (ASCs) seeded on collagen scaffolds. Adipose tissue from a single volunteer was used for the following preparations: purified adipose tissue, isolated mature adipocytes (free-cell graft), cultured ASCs without scaffold (free-cell graft), collagen scaffold only, cultured ASCs in collagen scaffold without and with bioactive factors, and freshly-isolated ASCs in collagen scaffold. These were grafted on 18 nude mice for 2months, after which specimens were evaluated grossly and histologically using hematoxylin-phloxine-safran (HPS), Oil-Red-O, and antivimentin labeling. Specimens and animals were weighed before implantation and after explantation, and weight values were statistically analyzed. Free-cell grafts (mature adipocytes and free ASCs) showed complete resorption in 50 and 60% of the animals (remaining weight fraction was 22.5 and 5.3%, respectively). The survival of purified adipose tissue was 81.8% (statistically greater compared with free-cell grafts; p<0.05). In the ASCs-scaffold association, the remaining weight fractions (87.3-70.4%) were statistically greater than in free-cell grafts (5.3-22.5%; p<0.05), but the difference between ASC-scaffolds and fat grafts was not statistically significant. These results were confirmed by clinical and histologic observations. Three-dimensional collagen scaffolds seem to improve survival of ASCs compared with free-cell grafts (adipocytes and free ASCs).

The Effect of Epidermal Growth Factor on Autogenous Fat Graft

Autogenous fat grafting is widely used for the correction of soft tissue contour deformity. However, the high absorption rate results in the need for overcorrection, and graft longevity is unpredictable. The authors hypothesized that epidermal growth factor (EGF), a potent stimulator of neovascularization, would improve fat graft survival. The experiment used two groups of New Zealand White Rabbit ear. Inguinal fat was harvested and injected with EGF or saline (n=24, each group). The 48 cases of fat grafting were managed for observation of volume and morphologic change. The fat was harvested 3months after the autogenous graft. The survival rate and the degree of neovascularization were measured. The grafts in the EGF group had a significantly higher survival rate than those in the control group. Histologic examination of the grafts demonstrated an increase in neovascularization and maintenance of fat cell morphology. These findings show that EGF can enhance fat graft survival and degree of neovascularization. Further well-controlled studies are required before EGF is used for clinical purposes.