Fat grafting to the breast and adipose-derived stem cells: recent scientific consensus and controversy

Metformin and adipose-derived stem cell combination therapy alleviates radiation-induced skin fibrosis in mice

BACKGROUND

Radiation therapy often leads to late radiation-induced skin fibrosis (RISF), causing movement impairment and discomfort. We conducted a comprehensive study to assess the effectiveness of metformin and adipose-derived stem cells (ASCs), whether autologous or allogeneic, individually or in combination therapy, in mitigating RISF.

METHODS

Using a female C57BL/6J mouse model subjected to hind limb irradiation as a representative RISF model, we evaluated metformin, ASCs, or their combination in two contexts: prophylactic (started on day 1 post-irradiation) and therapeutic (initiated on day 14 post-irradiation, coinciding with fibrosis symptoms). We measured limb movement, examined skin histology, and analyzed gene expression to assess treatment efficacy.

RESULTS

Prophylactic metformin and ASCs, whether autologous or allogeneic, effectively prevented late fibrosis, with metformin showing promising results. However, combination therapy did not provide additional benefits when used prophylactically. Autologous ASCs, alone or with metformin, proved most effective against late-stage RISF. Prophylactic intervention outperformed late therapy for mitigating radiation skin damage. Co-culture studies revealed that ASCs and metformin downregulated inflammation and fibrotic gene expression in both mouse and human fibroblasts.

CONCLUSIONS

Our study suggests metformin's potential as a prophylactic measure to prevent RISF, and the combination of ASCs and metformin holds promise for late-stage RISF treatment. These findings have clinical implications for improving the quality of life for those affected by radiation-induced skin fibrosis.

Human adipose ECM alleviates radiation-induced skin fibrosis via endothelial cell-mediated M2 macrophage polarization

Radiation therapy can lead to late radiation-induced skin fibrosis (RISF), causing movement restriction, pain, and organ dysfunction. This study evaluated adipose-derived extracellular matrix (Ad-ECM) as a mitigator of RISF. Female C57BL/6J mice that were irradiated developed fibrosis, which was mitigated by a single local Ad-ECM injection, improving limb movement and reducing epithelium thickness and collagen deposition. Ad-ECM treatment resulted in decreased expression of pro-inflammatory and fibrotic genes, and upregulation of anti-inflammatory cytokines, promoting M2 macrophage polarization. Co-culture of irradiated human fibroblasts with Ad-ECM down-modulated fibrotic gene expression and enhanced bone marrow cell migration. Ad-ECM treatment also increased interleukin (IL)-4, IL-5, and IL-15 expression in endothelial cells, stimulating M2 macrophage polarization and alleviating RISF. Prophylactic use of Ad-ECM showed effectiveness in mitigation. This study suggests Ad-ECM's potential in treating chronic-stage fibrosis.

A Study on Breast Augmentation Using Fat Grafting With Stromal Vascular Fraction

BACKGROUND

Stromal vascular fraction (SVF) and fat grafting are emerging alternatives to implants for breast augmentation. However, the lack of controlled clinical data has led to conflicting results regarding the effectiveness of surgical treatments. This study aimed to identify the key factors affecting the outcomes of fat grafting with SVF and to recognize novel methods to improve the retention rate.

PATIENTS AND METHODS

In total, 384 women underwent breast augmentation using fat grafting with SVF. The patients were preoperatively and postoperatively managed and recalled for follow-up at 3, 6, and 18 months.

RESULTS

The average volume of the injection in the left breast was 162.35 mL (range, 50-260 mL). The postoperative retention rates were 78.65% in 384 patients at 3 months, 77.17% in 273 patients at 6 months, and 77.48% in 102 patients at 18 months. The retention rates were compared based on the number of SVF cells; patients with more than 60 million cells had a retention rate of 70.77%, and those with less than 60 million cells had a retention rate of 85.60% at 18 months. The retention rates at the 18-month follow-up were 65.62% and 85.09% in stiff and soft breasts, respectively. A higher number of cells in the SVF was associated with a greater retention volume, and the retention volume was greater in patients with soft breasts.Given the higher use of the right arm, after 18 months of the surgery, the retention rate of the right breast (60.35%) was lower than that of the left breast (77.48%) ( P < 0.05; t = -13.199).

CONCLUSIONS

Limiting arm movement, increasing the number of cells in the SVF, and improving the skin tension might enhance the retention rate in patients undergoing breast augmentation.

Assessment of human adipose-derived stem cell on surface-modified silicone implant to reduce capsular contracture formation

Medical devices made from poly(dimethylsiloxane) (PDMS)-based silicone implants have been broadly used owing to their inert properties, biocompatibility, and low toxicity. However, long-term implantation is usually associated with complications, such as capsular contracture due to excessive local inflammatory response, subsequently requiring implant removal. Therefore, modification of the silicone surface to reduce a risk of capsular contracture has attracted increasing attention. Human adipose-derived stem cells (hASCs) are known to provide potentially therapeutic applications for tissue engineering, regenerative medicine, and reconstructive surgery. Herein, hASCs coating on a PDMS (hASC-PDMS) or itaconic acid (IA)-conjugated PDMS (hASC-IA-PDMS) surface is examined to determine its biocompatibility for reducing capsular contracture on the PDMS surface. In vitro cell cytotoxicity evaluation showed that hASCs on IA-PDMS exhibit higher cell viability than hASCs on PDMS. A lower release of proinflammatory cytokines is observed in hASC-PDMS and hASC-IA-PDMS compared to the cells on plate. Multiple factors, including in vivo mRNA expression levels of cytokines related to fibrosis; number of inflammatory cells; number of macrophages and myofibroblasts; capsule thickness; and collagen density following implantation in rats for 60 days, indicate that incorporated coating hASCs on PDMSs most effectively reduces capsular contracture. This study demonstrates the potential of hASCs coating for the modification of PDMS surfaces in enhancing surface biocompatibility for reducing capsular contracture of PDMS-based medical devices.

Adipose-derived stem cells (ADSCs) inhibit the expression of anti-apoptosis proteins through up-regulation of ATF4 on breast cancer cells

Background

While current basic studies indicate adipose-derived stem cells (ADSCs) can promote cell proliferation, clinical trials have shown no significant difference in breast cancer recurrence rates for patients with or without autologous fat grafting (AFG). In this study we attempted to explore the underlying mechanism for these contradictory results.

Methods

ADSCs and umbilical mesenchymal stem cells (UMSCs) were co-cultured with breast cancer cells (MCF-7 and MDA-MB-231), and the cell viability analyzed by CCK-8 cell proliferation assay, TUNEL assay and immunofluorescence assay. In addition, real-time quantitative polymerase chain reaction (RT-qPCR) experiments and Western blot analysis were used to detect the mRNA and protein expression of activating transcription factor 4 (ATF4) and its downstream gene (MCL1 & BCL2), respectively.

Results

Co-cultured ADSCs could promote cell proliferation and cell apoptosis, and up-regulate ATF4 expression both in MCF-7 and MDA-MB-231. While co-cultured UMSCs could only promote cell apoptosis in MCF-7. Interestingly, we found that when co-cultured ADSCs, the expression of MCL1 and BCL2 protein was decreased, even if their mRNA expression was up-regulated both in MCF-7 and MDA-MB-231.

Conclusions

Co-cultured ADSCs can up-regulate ATF4 expression, then interfere with the translation process of MCL1 and BCL2 mRNA and induce cell apoptosis. These data provide insight into the safety characteristics of AFG.

Evaluation of the ex vivo Effects of Tamoxifen on Adipose-Derived Stem Cells: A Pilot Study

Autologous fat grafting (AFG) is a safe and minimally invasive procedure to correct soft tissue defects. The benefit of AFG is attributed to adipose-derived stem cells (ASCs) in fat tissue graft. This technique is useful also in patients undergoing reconstructive surgery following quadrantectomy for breast cancer. However, these patients are frequently treated with tamoxifen. We evaluated the ex vivo effects of tamoxifen on ASCs to understand if cellular functions of ASCs are affected. We selected 24 female patients; 10 of which were breast cancer patients treated with quadrantectomy and tamoxifen. As control group, we selected 14 healthy female subjects (9 premenopausal and 5 menopausal). We found that tamoxifen has no effect on cellular proliferation, VEGF secretion or apoptosis of ASCs. The gene expression assessment demonstrated no impairment in differentiation capacity of ASCs. Our results showed that tamoxifen has no effect on cellular functions of ASCs for the first time in an ex vivo single-center study.

Therapeutic Reversal of Radiotherapy Injury to Pro-fibrotic Dysfunctional Fibroblasts In Vitro Using Adipose-derived Stem Cells

Cancer patients often require radiotherapy (RTx) to enhance their survival. Unfortunately, RTx also damages nearby healthy non-cancer tissues, leading to progressive fibrotic soft-tissue injury, consisting of pain, contracture, tissue-breakdown, infection, and lymphoedema. Mechanisms underlying the clinically observed ability of fat grafting to ameliorate some of these effects, however, are poorly understood. It was hypothesized that RTx significantly alters fibroblast cell function and the paracrine secretome of adipose-derived stem cells (ADSC) may mitigate these changes.

Methods

To investigate cellular changes resulting in the fibrotic side-effects of RTx, cultured normal human dermal fibroblasts (NHDF) were irradiated (10Gy), then studied using functional assays that reflect key fibroblast functions, and compared with unirradiated controls. RNA-Seq and targeted microarrays (with specific examination of TGFβ) were performed to elucidate altered gene pathways. Finally, conditioned-media from ADSC was used to treat irradiated fibroblasts and model fat graft surgery.

Results

RTx altered NHDF morphology, with cellular functional changes reflecting transition into a more invasive phenotype: increased migration, adhesion, contractility, and disordered invasion. Changes in genes regulating collagen and MMP homeostasis and cell-cycle progression were also detected. However, TGFβ was not identified as a key intracellular regulator of the fibroblast response. Finally, treatment with ADSC-conditioned media reversed the RTx-induced hypermigratory state of NHDF.

Conclusions

Our findings regarding cellular and molecular changes in irradiated fibroblasts help explain clinical manifestations of debilitating RTx-induced fibrosis. ADSC-secretome-mediated reversal indicated that these constituents may be used to combat the devastating side-effects of excessive unwanted fibrosis in RTx and other human fibrotic diseases.

Adipose-Derived Stem Cell Therapy Ameliorates Ionizing Irradiation Fibrosis via Hepatocyte Growth Factor-Mediated Transforming Growth Factor-β Downregulation and Recruitment of Bone Marrow Cells

Radiation therapy to anatomic regions, including the head and neck, chest wall, and extremities, can produce radiation-induced fibrosis (RIF). To elucidate the cellular and molecular mechanism(s) involved in RIF, female C57BL/6J mice were irradiated to the right flank to 35 Gy in single fraction using 6 Mv electrons. Radiation fibrosis was detected by day 14, was increased by day 28, and confirmed by Masson's trichrome histological staining for collagen. Biopsied tissue at day 14 showed an increase in expression of fibrosis-related genes including transforming growth factor-β (TGF-β) and collagens 1-6. A single adipose-derived stem cell (ASC) injection on day 28 at the irradiated site decreased by day 40: epithelial thickness, collagen deposition, and significantly improved limb excursion compared with irradiated controls. Noncontact transwell coculture of ASCs above a monolayer of irradiated human foreskin fibroblasts downregulated fibrosis-related genes TGF-β, connective tissue growth factor, interleukin-1, NF-kB, tumor necrosis factor, and collagens 1-6. Hepatocyte growth factor (HGF) secreted by ASCs was identified as a novel mechanism by which ASCs exert antifibrotic effects by downregulating fibrotic gene expression in irradiated cells and recruiting bone marrow cells to the irradiated site. In conclusion, these data indicate a mechanistic role of HGF secreted by ASCs in reducing RIF. Stem Cells 2019;37:791-802.

Adipose-Derived Stem Cells in Aesthetic Surgery

Adipose-derived stem cells (ADSC) have come to be viewed as a ubiquitous solution for aesthetic and reconstructive problems involving loss of tissue volume and age or radiation-induced loss of tissue pliability and vascularity. As the theoretical potential of "stem cell therapy" has captured the public imagination, so the commercial potential of novel therapies is being exploited beyond scientifically sound, hypothesis-driven paradigms and in the absence of evidence establishing clinical efficacy and safety. Moreover, with variations in methods of isolation, manipulation, and reintroduction described, it is unclear how the practitioner with an interest in ADSC can harness the clinical potential in reproducible and scientifically measurable ways. This Continuing Medical Education (CME) article presents a summary of our understanding of what ADSC are, their utility within the field of aesthetic surgery, and the current and future directions for adipose stem cell research.

A systematic review of the effectiveness and complications of fat grafting in the facial region

INTRODUCTION

The objective of this study was to evaluate the safety and efficacy of fat grafting to the facial region for the reconstruction and aesthetic enhancement of facial contour.

METHODS

A systematic literature review of the National Library of Medicine (PubMed), MEDLINE and Cochrane databases was performed. Studies involving the outcomes of autologous fat grafting to correct or enhance contour defects of the face were included. Extracted data included patient demographics, harvest and injection sites, graft harvesting and injection technique, mean injected volume, retained volume percentage and complications.

RESULTS

Forty-three articles met the inclusion criteria, resulting in 4577 patients with various facial contour defects treated with autologous fat grafting. Injection sites were categorized by anatomic facial regions as upper (32.5%), middle (53%) and lower face (14.5%). The mean volume of injected fat was 16.9 ml. The mean weighted volume retention of non-enriched grafts was 41.63% at the time of follow up (mean 13.9 months). A total of 104 (2.27%) complications were reported including asymmetry (74), skin irregularities (14), prolonged edema (4), graft hypertrophy (4), fat necrosis (3), infection (2), erythema (1), telangiectasia (1), and activation of acne (1).

CONCLUSION

The present study represents the first systematic review of fat grafting in the facial region, a widely-performed procedure within plastic surgery practice. Importantly, it presents pooled important data such as retained grafting volume and complication rates in this anatomical region, providing clinicians with more accurate information with which to guide their decision-making and patient education.

Volume Retention, Metabolism, and Cellular Composition of Human Fat Xenografts

Background

To optimize the take of transferred fat, better understanding of fat graft morphology and growth properties in vivo is critical. We aim to evaluate survival, volume retention, metabolism, and cellular composition of various aliquots of human fat xenografts.

Methods

Twenty athymic nude mice were injected subcutaneously in opposing flanks with 0.1 ml (small) and 1.0 ml (large) aliquots of human fat graft. Volume (ultrasound) of fat aliquots was measured at baseline, 1, 3, and 12 weeks after implantation. Tissue metabolism (¹⁸F-FDG), Hematoxylin and Eosin, special stains, and immunohistochemical analysis were performed at 3 and 12 weeks to determine graft viability, cell origin, and proliferative activity.

Results

Only 1 of 10 small grafts were detected after 12 weeks by ultrasound and 5 of 10 were found at necropsy. Volume of large grafts decreased significantly from baseline at 3 (827 ± 195 mm³ versus 953 ± 122 mm³; P = 0.004) and 12 weeks (515 ± 163 mm³ versus 953 ± 122 mm³; P = 0.0001). Metabolism increased with time in small (0.6 ± 0.4%ID/g versus 2.0 ± 1.1%ID/g, P = 0.01) and large grafts (0.4 ± 0.3%ID/g versus 1.4 ± 0.9 %ID/g; P = 0.005). Large grafts viability decreased between 3 and 12 weeks (72 ± 20% versus 31 ± 30%; P = 0.012) although small graft viability remained unchanged. Viable and proliferating human and mouse adipocytes and chimeric blood vessels were seen within grafts at both time points.

Conclusions

Larger graft aliquot was associated with better volume retention by ultrasound but lower viability by histology. Graft metabolism increased with time irrespective of aliquot size potentially due to regenerative processes of both donor and recipient origin.

Therapeutic effects of a recombinant human collagen peptide bioscaffold with human adipose-derived stem cells on impaired wound healing after radiotherapy

Chronic changes following radiotherapy include alterations in tissue-resident stem cells and vasculatures, which can lead to impaired wound healing. In this study, novel recombinant human collagen peptide (rhCP) scaffolds were evaluated as a biomaterial carrier for cellular regenerative therapy. Human adipose-derived stem cells (hASCs) were successfully cultured on rhCP scaffolds. By hASC culture on rhCP, microarray assay indicated that expression of genes related to cell proliferation and extracellular matrix production was upregulated. Pathway analyses revealed that signaling pathways related to inflammatory suppression and cell growth promotion were activated as well as signaling pathways consistent with some growth factors including vascular endothelial growth factor, hepatocyte growth factor, and transforming growth factor beta, although gene expression of these growth factors was not upregulated. These findings suggest the rhCP scaffold showed similar biological actions to cytokines regulating cell growth and immunity. In subsequent impaired wound healing experiments using a locally irradiated (20 Gray) mouse, wound treatment with rhCP sponges combined with cultured hASCs and human umbilical vein endothelial cells accelerated wound closure compared with wounds treated with rhCP with hASCs alone, rhCP only, and control (dressing alone), with better healing observed according to this order. These results indicating the therapeutic value of rhCP scaffolds as a topical biomaterial dressing and a biocarrier of stem cells and vascular endothelial cells for regenerating therapies. The combination of rhCP and functional cells was suggested to be a potential tool for revitalizing stem cell-depleted conditions such as radiation tissue damage.

Breast Augmentation and Reconstruction from a Regenerative Medicine Point of View: State of the Art and Future Perspectives

Breast reconstruction and augmentation are very common procedures, yet the prevailing current methods utilize silicone implants that may have significant local complications requiring reoperation. Lipofillling is increasingly used to contour and is considered safe, however, its utility is limited by significant volume loss. A new approach could offer an alternative and increase the scope of patient choice. A small number of teams around the world are investigating a breast tissue engineering (TE) paradigm. Conventional breast TE concepts are based on seeding a scaffold with the patients' own stem cells. However, the clinical viability of many of these approaches is limited by their costs in relevant volumes. In this article the state of the art of tissue-engineered breast reconstruction is reviewed and future perspectives are presented and discussed.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Adipose-Derived Stromal Vascular Fraction Differentially Expands Breast Progenitors in Tissue Adjacent to Tumors Compared to Healthy Breast Tissue

Supplemental Digital Content is available in the text.

Background:

Autologous fat grafts supplemented with adipose-derived stromal vascular fraction are used in reconstructive and cosmetic breast procedures. Stromal vascular fraction contains adipose-derived stem cells that are thought to encourage wound healing, tissue regeneration, and graft retention. Although use of stromal vascular fraction has provided exciting perspectives for aesthetic procedures, no studies have yet been conducted to determine whether its cells contribute to breast tissue regeneration. The authors examined the effect of these cells on the expansion of human breast epithelial progenitors.

Methods:

From patients undergoing reconstructive breast surgery following mastectomies, abdominal fat, matching tissue adjacent to breast tumors, and the contralateral non–tumor-containing breast tissue were obtained. Ex vivo co-cultures using breast epithelial cells and the stromal vascular fraction cells were used to study the expansion potential of breast progenitors. Breast reduction samples were collected as a source of healthy breast cells.

Results:

The authors observed that progenitors present in healthy breast tissue or contralateral non–tumor-containing breast tissue showed significant and robust expansion in the presence of stromal vascular fraction (5.2- and 4.8-fold, respectively). Whereas the healthy progenitors expanded up to 3-fold without the stromal vascular fraction cells, the expansion of tissue adjacent to breast tumor progenitors required the presence of stromal vascular fraction cells, leading to a 7-fold expansion, which was significantly higher than the expansion of healthy progenitors with stromal vascular fraction.

Conclusions:

The use of stromal vascular fraction might be more beneficial to reconstructive operations following mastectomies compared with cosmetic corrections of the healthy breast. Future studies are required to examine the potential risk factors associated with its use.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, V.

In vitro effects of tamoxifen on adipose-derived stem cells

In breast reconstructive procedures, adipose-derived stem cells (ASCs) that are present in clinical fat grafting isolates are considered to play the main role in improving wound healing. In patients following chemotherapy for breast cancer, poor soft tissue wound healing is a major problem. However, it is unclear if tamoxifen (TAM) as the most widely used hormonal therapeutic agent for breast cancer treatment, affects the ASCs and ultimately wound healing. This study evaluated whether TAM exposure to in vitro human ASCs modulate cellular functions. Human ASCs were isolated and treated with TAM at various concentrations. The effects of TAM on cell cycle, cell viability and proliferation rates of ASCs were examined by growth curves, MTT assay and BrdU incorporation, respectively. Annexin V and JC-1 Mitochondrial Membrane Potential assays were used to analyze ASC apoptosis rates. ASCs were cultured in derivative-specific differentiation media with or without TAM (5 uM) for 3 weeks. Adipogenic and osteogenic differentiation levels were measured by quantitative RT-PCR and histological staining. TAM has cytotoxic effects on human ASCs through apoptosis and inhibition of proliferation in dose- and time-dependent manners. TAM treatment significantly down-regulates the capacity of ASCs for adipogenic and osteogenic differentiation (p<0.05 vs. control), and inhibit the ability of the ASCs to subsequently formed cords in Matrigel. This study is the first findings to our knowledge that demonstrated that TAM inhibited ASC proliferation and multi-lineage ASC differentiation rates. These results may provide insight into the role of TAM with associated poor soft tissue wound healing and decreased fat graft survival in cancer patients receiving TAM.

Fat transfer and fatal macroembolization

Fat embolism is usually associated with long bone fractures or other trauma. The diagnosis is usually clinical, and in most cases, emboli are not fatal and not usually seen on gross examination. At the Los Angeles County Coroner's Office, we autopsied the victim of fatal macroscopic fat embolization to the lungs. The patient died during buttock enhancement surgery when fat from liposuction was injected into her buttocks. Fat embolism from liposuction and fat injection is reportedly rare, and macroscopic embolization is rarer still. Varicose veins can occur in the area of the sciatic notch and are known to cause painful sciatica symptoms. We suggest them as a potential conduit for macroscopic fat to reach the lungs. Simple pre-operative questioning for sciatica symptoms and possible radiologic study to rule out sciatic varices seem prudent before undertaking buttock-enhancing surgery. Careful fat injection with pre-aspiration is always advised.

Adipose-derived stem cells in radiotherapy injury: a new frontier

Radiotherapy is increasingly used to treat numerous human malignancies. In addition to the beneficial anti-cancer effects, there are a series of undesirable effects on normal host tissues surrounding the target tumor. While the early effects of radiotherapy (desquamation, erythema, and hair loss) typically resolve, the chronic effects persist as unpredictable and often troublesome sequelae of cancer treatment, long after oncological treatment has been completed. Plastic surgeons are often called upon to treat the problems subsequently arising in irradiated tissues, such as recurrent infection, impaired healing, fibrosis, contracture, and/or lymphedema. Recently, it was anecdotally noted - then validated in more robust animal and human studies - that fat grafting can ameliorate some of these chronic tissue effects. Despite the widespread usage of fat grafting, the mechanism of its action remains poorly understood. This review provides an overview of the current understanding of: (i) mechanisms of chronic radiation injury and its clinical manifestations; (ii) biological properties of fat grafts and their key constituent, adipose-derived stem cells (ADSCs); and (iii) the role of ADSCs in radiotherapy-induced soft-tissue injury.

Human adipose tissue-derived stromal/stem cells promote migration and early metastasis of triple negative breast cancer xenografts

Background

Fat grafting is used to restore breast defects after surgical resection of breast tumors. Supplementing fat grafts with adipose tissue-derived stromal/stem cells (ASCs) is proposed to improve the regenerative/restorative ability of the graft and retention. However, long term safety for ASC grafting in proximity of residual breast cancer cells is unknown. The objective of this study was to determine the impact of human ASCs derived from abdominal lipoaspirates of three donors, on a human breast cancer model that exhibits early metastasis.

Methodology/Principal Findings

Human MDA-MB-231 breast cancer cells represents “triple negative” breast cancer that exhibits early micrometastasis to multiple mouse organs [1]. Human ASCs were derived from abdominal adipose tissue from three healthy female donors. Indirect co-culture of MDA-MB-231 cells with ASCs, as well as direct co-culture demonstrated that ASCs had no effect on MDA-MB-231 growth. Indirect co-culture, and ASC conditioned medium (CM) stimulated migration of MDA-MB-231 cells. ASC/RFP cells from two donors co-injected with MDA-MB-231/GFP cells exhibited a donor effect for stimulation of primary tumor xenografts. Both ASC donors stimulated metastasis. ASC/RFP cells were viable, and integrated with MDA-MB-231/GFP cells in the tumor. Tumors from the co-injection group of one ASC donor exhibited elevated vimentin, matrix metalloproteinase-9 (MMP-9), IL-8, VEGF and microvessel density. The co-injection group exhibited visible metastases to the lung/liver and enlarged spleen not evident in mice injected with MDA-MB-231/GFP alone. Quantitation of the total area of GFP fluorescence and human chromosome 17 DNA in mouse organs, H&E stained paraffin sections and fluorescent microscopy confirmed multi-focal metastases to lung/liver/spleen in the co-injection group without evidence of ASC/RFP cells.

Conclusions

Human ASCs derived from abdominal lipoaspirates of two donors stimulated metastasis of MDA-MB-231 breast tumor xenografts to multiple mouse organs. MDA-MB-231 tumors co-injected with ASCs from one donor exhibited partial EMT, expression of MMP-9, and increased angiogenesis.

Autologous bone-marrow-derived-mononuclear-cells-enriched fat transplantation in breast augmentation: evaluation of clinical outcomes and aesthetic results in a 30-year-old female

Autologous fat transfer (lipofilling) is becoming an invaluable tool for breast augmentation as well as for breast reconstruction. Autologous lipofilling has several advantages, including biocompatibility, versatility, natural appearance, and low donor site morbidity. The main limitation is unpredictable fat graft resorption, which ranges from 25% to 80%, probably as a result of ischaemia and lack of neoangiogenesis. To obviate these disadvantages, several studies have searched for new ways of increasing the viability of the transplanted fat tissue. One promising approach is to enrich the fat graft with autologous bone-marrow-derived mononuclear cells (BMMNCs) before transplantation. BMMNCs produce many angiogenic and antiapoptotic growth factors, and their secretion is significantly enhanced by hypoxia. All of these mechanisms of actions could be beneficial for the stimulation of angiogenesis in ischemic tissues by BMMNCs administration. In our aesthetic surgery practice, we use fat transplantation enriched with BMMNCs, which caused a significant improvement in survival of fat grafts, compared with that of traditional lipofilling. Our experience with freshly isolated autologous fat enriched with BMMNCs for breast augmentation procedures is presented. The concept of this surgical and tissue handling technique is based on ability of BMMNCs to stimulate blood vessel growth.

Comparative analysis of adipose-derived mesenchymal stem cells isolated from abdominal and breast tissue

BACKGROUND

Adipose-derived mesenchymal stem cells (ADSC) may have a potential dual role in soft tissue augmentation by suppressing inflammation and promoting regeneration. Due to these properties, there is increasing interest in their potential use in autologous fat grafting, particularly to the breast.

OBJECTIVES

The authors isolate and compare ADSC derived from abdominal and breast tissues with a hypothesis that different adipose tissue sources may demonstrate different functional characteristics affecting outcomes in autologous cell transplantation in reconstructive and aesthetic surgery.

METHODS

Adipose-derived mesenchymal stem cells from abdominal and breast tissues were isolated and compared in terms of surface marker expression, differentiation capabilities, and both fibroblast growth factor (FGF) and receptor expression. Immunophenotype of macrophages was also investigated using cell surface markers following a 7-day co-culture period with ADSC.

RESULTS

Results showed similar cell surface phenotype and multilineage differentiation capabilities of ADSC derived from abdominal and breast tissues. Variations of FGF expression were demonstrated on reverse transcription polymerase chain reaction, with a significantly higher expression of FGF2 seen in breast ADSC. Following the 7-day co-culture period, increased expression of the anti-inflammatory surface marker CD206 was identified, with decreased CD16 and human leukocyte antigen-DR on macrophages co-cultured with ADSC compared with controls.

CONCLUSIONS

The data indicate similarities between ADSC derived from abdominal and breast tissues. Significant differences were seen, however, in the expression of FGF2, which is important in angiogenesis and wound healing. The results support the utility of ADSC in cell-based therapies such as autologous fat grafting.

Comparison of 3 techniques of fat grafting and cell-supplemented lipotransfer in athymic rats: a pilot study

BACKGROUND

Given the wide application of autologous fat grafting, a new emphasis on fat processing techniques has emerged in an effort to limit unpredictable degrees of resorption often seen with this procedure. With the growing interest in regenerative medicine, approaches to supplement fat grafts with adipose-derived stem cells are evolving in hopes of promoting vascularization and neoadipogenesis.

OBJECTIVE

The authors evaluated the outcomes of the most common processing techniques for fat grafting--decantation, washing, high-speed centrifugation--and stromal vascular cell-supplemented lipotransfer to determine which method yields a higher percentage of retention and better quality graft.

METHODS

A total of 32 subcutaneous injections of processed human lipoaspirate were carried out in 8 athymic rats. Each animal received all 4 processing conditions, with end points at 4, 8, and 12 weeks postinjection. Evaluation of graft survival included serial measurements of volume retention and histologic analysis.

RESULTS

At 12 weeks postinjection, cell-supplemented and centrifuged grafts showed the most consistent volume maintenance. Based on histologic analysis, cell-supplemented and washed grafts had higher scores of viability and vascularity, with the former presenting the least cystic necrosis and calcification as well as minimal inflammation.

CONCLUSIONS

Cell-supplemented lipotransfer had optimal outcomes for graft retention, viability, and vascularity, while washing resulted in high viability with a less intensive process. High-speed centrifugation resulted in consistent volume retention but lower viability. Each of these approaches is ideal under different circumstances and contributes to the versatility and reliability of fat grafting.

The use of abdominal free fat for volumetric augmentation and primary dural closure in supratentorial skull base surgery: managing the stigma of a temporal defect

The most prominent stigma of supratentorial skull base surgery is the defect caused by wasting of the temporalis muscle by denervation, devascularization, or rotation of the muscle. Any of the above may lead to a unilateral temporal deformity informally referred to patients as "the divot in my head." Abdominal free fat grafting has been used by surgeons for years to close posterior fossa defects with excellent results. We present our experience using abdominal free fat grafts to improve cosmetic results and to prevent cerebrospinal fluid leaks in supratentorial skull base surgery. The basic technique and its benefits are described.

Effect of ASCs on the graft survival rates of fat particles in rabbits

This study was conducted to explore the effect of adipose-derived stem cells (ASCs) on the graft survival rates of fat particles in rabbits. Six domestic rabbits were used for a 3-month study; 1.4 grams of fat tissues were harvested from the bilateral inguinal regions of each animal. They were cut into granules and divided into three parts (A = 0.4 g, B = 0.4 g, and C = 0.6 g). Part A was centrifuged after 0.075% collagenase digestion for isolation of the stromal vascular fraction (SVF). About 0.2 grams of SVF containing ASCs was obtained, and then incorporated with part B to create a treated group, whereas part C was treated as a control group. The tissues in both groups were randomly transplanted into a subcutaneous space that had been created on each side of the dorsal midline of the rabbit. The grafts were taken out after 3 months for calculation of the survival rates. The graft survival rate in the treated group was 23.56 ± 2.49%, while that in the control group was 11.06 ± 2.10%. The graft survival rate in the treated group increased significantly, compared with in the control group (p < 0.01). Improved transplantation effects may be obtained by implanting the fat particles mixed with ASCs. It is suggested that this approach has the potential for becoming a new method of fat graft in clinical practice.

Clinical use of Dieletrophoresis separation for live Adipose derived stem cells

BACKGROUND

Microelectrode dieletrophoresis capture of live cells has been explored in animal and cellular models ex-vivo. Currently, there is no clinical data available regarding the safety and efficacy of dielectrophoresis (DEP) buffers and microcurrent manipulation in humans, despite copious pre-clinical studies suggesting its safety. The purpose of this study was to determine if DEP isolation of SVF using minimal manipulation methods is safe and efficacious for use in humans using the hand lipotransfer model.

METHODS

Autologous stromal vascular fraction cells (SVF) were obtained from lipoaspirate by collagenase digestion and centrifugation. The final mixture of live and dead cells was further processed using a custom DEP microelectrode array and microcurrent generator to isolate only live nucleated cells. Lipotransfer was completed using fat graft enhanced with either standard processed SVF (control) versus DEP filtered SVF (experimental). Spectral photography, ultrasound and biometric measurements were obtained at post operatively days 1, 4, 7, 14, 30, 60 and 90.

RESULTS

The DEP filter was capable of increasing SVF viability counts from 74.3 ± 2.0% to 94.7 ± 2.1%. Surrogate markers of inflammation (temperature, soft tissue swelling, pain and diminished range of motion) were more profound on the control hand. Clinical improvement in hand appearance was appreciated in both hands, though the control hand exclusively sustained late phase erosive skin breaks on post operative day 7. No skin breaks were appreciated on the DEP-SVF treated hand. Early fat engraftment failure was noted on the control hand thenar web space at 3 months post surgery.

DISCUSSION

No immediate hypersensitivity or adverse reaction was appreciated with the DEP-SVF treated hand. In fact, the control hand experienced skin disruption and mild superficial cellulitis, whereas the experimental hand did not experience this complication, suggesting a possible "protective" effect with DEP filtered SVF. Late ultrasound survey revealed larger and more frequent formation of oil cysts in the control hand, also suggesting greater risk of engraftment failure with standard lipotransfer.

CONCLUSION

Clinical DEP appears safe and efficacious for human use. The DEP microelectrode array was found to be versatile and robust in efficiently isolating live SVF cells from dead cells and cellular debris in a time sensitive clinical setting.

Natural Breast Augmentation or Fat Transfer

Natural breast augmentation, or fat transfer, involves taking fat cells from one area of the body and injecting them into another area, such as the breast. This can be done for cosmetic reasons after a lumpectomy or other surgical procedures that affect the shape of the breast. Breast augmentation is also being used electively by some women to enhance the appearance of their breasts. Defects such as asymmetry, sagging, or indentations have been improved with fat transfers. The changes of the breast tissue from the reaction to the new fat can also change the outcome of mammograms and sonograms. The interpreting radiologist might recommend a biopsy to exclude the possibility of missing a malignant lesion. These two case reports give sonographers an idea of what additional questions they may need to ask patients to clarify their history.

Potential of mesenchymal stem cell applications in plastic and reconstructive surgery

: Novel therapy with mesenchymal stem cells from bone marrow, adipose tissue, or other sources has raised high hopes for treatment of a variety of diseases. For plastic and reconstructive surgery, first pilot studies and clinical trials using stem cells for treatment of chronic wounds, radiation injury, or soft tissue augmentation have furnished encouraging results compared with the limitations of standard therapy, for example autologous fat grafting. Further research must be conducted to reveal the complex physiological interactions between activated stem cells and the host environment. Long-term effects and safety aspects of these novel treatment options also require randomized controlled studies. For future clinical applications, guidelines and standardized procedures for stem cell isolation and preparation, and techniques for application must be established.

Autologous fat grafting for primary breast augmentation: a systematic review

As the technique of autologous fat grafting is being refined and perfected, its clinical applications are expanding. The use of autologous fat grafting for primary breast augmentation is controversial due to a lack of clarity regarding its safety and efficacy. Most notably, concerns about interference with the detection of breast cancer have been raised, but these have not been clearly addressed in the literature. To help surgeons gain further insight, the authors conducted a systematic review of the literature, carefully comparing technique, clinical outcome, radiologic impact, and complications in all available data on this subject. Although an optimal method of autologous fat grafting for primary breast augmentation is yet to be standardized, further strong evidence-based studies are necessary to confirm the findings of this approach.

The safety of autologous fat transfer in breast cancer: lessons from stem cell biology

Autologous fat grafting is versatile tool in plastic surgery and is increasing used for reconstruction following breast conserving surgery for breast cancer. Part of the reconstructive qualities of the transferred fat may be due to the presence of adipose derived mesenchymal stem cells (ADMSC) playing an angiogenic and an adipogenic role. In this context it must be considered if autologously engrafted fat tissue could contribute to carcinogenesis following breast conserving surgery. In this article we review the current stem cell biology evidence on engraftment, transdifferentiation and potential carcinogenic contribution in the breast and other solid organ stem cell niches in an attempt to highlight possible areas of concern.

The use of autologous fat for facial rejuvenation

Adding volume to the aging face is a notion that has come into vogue as of late but is, however, not a new idea. With the advent of miro-liposuction techniques, there is renewed interest in the use of aspirated fat. Commercial fillers have a valuable place in the cosmetic surgeon's armamentarium and offer immediate volume correction with a more modest financial commitment. Nevertheless, the standardization of fat grafting techniques marks an exciting shift in facial aesthetics with the ability to correct all aspects of the aging face with safe, natural, and lasting results.

Diverse and active roles for adipocytes during mammary gland growth and function

The mammary gland is unique in its requirement to develop in close association with a depot of adipose tissue that is commonly referred to as the mammary fat pad. As discussed throughout this issue, the mammary fat pad represents a complex stromal microenvironment that includes a variety of cell types. In this article we focus on adipocytes as local regulators of epithelial cell growth and their function during lactation. Several important considerations arise from such a discussion. There is a clear and close interrelationship between different stromal tissue types within the mammary fat pad and its adipocytes. Furthermore, these relationships are both stage- and species-dependent, although many questions remain unanswered regarding their roles in these different states. Several lines of evidence also suggest that adipocytes within the mammary fat pad may function differently from those in other fat depots. Finally, past and future technologies present a variety of opportunities to model these complexities in order to more precisely delineate the many potential functions of adipocytes within the mammary glands. A thorough understanding of the role for this cell type in the mammary glands could present numerous opportunities to modify both breast cancer risk and lactation performance.