Importance of mesenchymal stem cells in autologous fat grafting: a systematic review of existing studies

Aspirin Stimulates the Osteogenic Differentiation of Human Adipose Tissue-Derived Stem Cells In Vitro

This study investigates the impact of acetylsalicylic acid (ASA), also known as aspirin, on adipose tissue-derived stem cells (ASCs), aiming to elucidate its dose-dependent effects on morphology, viability, proliferation, and osteogenic differentiation. Isolated and characterized human ASCs were exposed to 0 µM, 100 µM, 200 µM, 400 µM, 800 µM, 1000 µM, 10,000 µM, and 16,000 µM of ASA in vitro. Cell morphology, viability, and proliferation were evaluated with fluorescent live/dead staining, alamarBlue viability reagent, and CyQUANT® cell proliferation assay, respectively. Osteogenic differentiation under stimulation with 400 µM or 1000 µM of ASA was assessed with alizarin red staining and qPCR of selected osteogenic differentiation markers (RUNX2, SPP1, ALPL, BGLAP) over a 3- and 21-day-period. ASA doses ≤ 1000 µM showed no significant impact on cell viability and proliferation. Live/dead staining revealed a visible reduction in viable cell confluency for ASA concentrations ≥ 1000 µM. Doses of 10,000 µM and 16,000 µM of ASA exhibited a strong cytotoxic and anti-proliferative effect in ASCs. Alizarin red staining revealed enhanced calcium accretion under the influence of ASA, which was macro- and microscopically visible and significant for 1000 µM of ASA (p = 0.0092) in quantification if compared to osteogenic differentiation without ASA addition over a 21-day-period. This enhancement correlated with a more pronounced upregulation of osteogenic markers under ASA exposure (ns). Our results indicate a stimulatory effect of 1000 µM of ASA on the osteogenic differentiation of ASCs. Further research is needed to elucidate the precise molecular mechanisms underlying this effect; however, this discovery suggests promising opportunities for enhancing bone tissue engineering with ASCs as cell source.

Autologous Fat Grafting in Breast Augmentation: A Systematic Review Highlighting the Need for Clinical Caution

BACKGROUND

Autologous fat grafting (AFG) is a breast augmentation method for treating volume and contour abnormalities. This systematic review aims to summarize complications, radiologic safety, volume retention, and patient satisfaction associated with AFG.

METHODS

The PubMed, Embase, Google Scholar, Cochrane Central Register of Controlled Trials, Wiley library, clinical key/Elsevier, and EBSCO databases were searched for relevant studies from January of 2009 to March of 2022. Articles describing AFG for breast augmentation were selected based on predetermined inclusion and exclusion criteria. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were adhered to, and the study was registered on the International Prospective Register of Systematic Reviews. The Risk of Bias in Nonrandomized Studies of Interventions assessment was used to assess the quality of studies and the risk of bias was measured using the Cochrane Risk of Bias Assessment Tool for Nonrandomized Studies of Interventions.

RESULTS

A total of 35 studies comprising 3757 women were included. The average follow-up duration was 24.5 months (range, 1 to 372 months). The overall complication rate was 27.8%, with fat necrosis making up 43.7% of all complications. Average fat volume injected was 300 mL (range, 134 to 610 mL), and average volume retention was 58% (range, 44% to 83%). Volume retention was greater with supplementation of fat with platelet-rich plasma and stromal vascular fraction. The most common radiologic changes were fat necrosis (9.4%) and calcification (1.2%). After 1 year of follow-up, patient satisfaction was, on average, 92% (range, 83.2% to 97.5%). The included studies were of good quality and consisted of a moderate risk of bias.

CONCLUSIONS

AFG was associated with an overall complication rate of 27.8%. Additional supplementation of fat with platelet-rich plasma and stromal vascular fraction may improve graft survival. Despite poor volume retention being a persistent drawback, patient satisfaction remains high.

Cosmetic Breast Augmentation with Autologous Ex Vivo-Expanded Adipose-Derived Mesenchymal Stem/Stromal Cell (Stemform®)-Enriched Fat Grafts: A Study of the First Twenty-Two Real-World Patients

BACKGROUND

Fat grafting is commonly utilized in breast surgery, and since it was first described, clinicians and researchers have stridden towards improvement of graft retention. Current advancements include adding adipose-derived mesenchymal stem/stromal cells (MSC(AT)s), which have demonstrated promise for improved graft retention.

OBJECTIVES

This study reports outcomes for the first twenty-two patients undergoing breast augmentation (Stemform BA) or artificial implant replacement (Stemform AIR) with MSC(AT)-enriched fat in a real-world setting.

METHODS

Autologous MSC(AT)s were isolated and expanded ex vivo, then mixed with lipoaspirate and injected as enriched fat for Stemform BA and AIR. The breast volume was measured preoperatively and at 3 and 12 months postoperative using a 3D Infinity Dual-Lens Camera and LifeVizApp software. Additionally, independent plastic surgeons evaluated clinical images, and patient satisfaction was obtained at equal time points.

RESULTS

Twenty-two patients were included. All completed 3 and 12 months clinical follow-up and 3 months volume measurements. Nineteen patients completed 12 months volume measurements. The median fat graft retention at 12 months was 95.7% (IQR = 82.44-103.12%) for Stemform BA patients and 113.0% (IQR = 94.8-131.2%) for Stemform AIR patients. The Stemform BA patients had a median breast enlargement of 172.0% (IQR = 156.7-241.0%). The implant replacement volume of Stemform AIR patients was 102% (IQR = 85.1-130.3%). The patient reported 92.8% and 100% would elect to repeat treatment if they had the opportunity for Stemform BA and Stemform AIR, respectively.

CONCLUSION

Breast augmentation and breast implant replacement patients receiving ex vivo-expanded MSC(AT)-enriched fat grafts had high graft retention and patient satisfaction scores. The paper confirms the clinical efficacy of using ex vivo-expanded MSC(AT)s. Level of Evidence V 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 .

Three-dimensional spheroid formation of adipose-derived stem cells improves the survival of fat transplantation by enhance their therapeutic effect

Adipose-derived stem cells (ADSCs) have important applications in basic research, especially in fat transplantation. Some studies have found that three-dimensional (3D) spheroids formed by mesenchymal stem cells have enhanced therapeutic potential. However, the fundamental basics of this effect are still being discussed. ADSCs were harvested from subcutaneous adipose tissues and 3D spheroids were formed by the automatic aggregation of ADSCs in a non-adhesive 6-well plate. Oxygen glucose deprivation (OGD) was used to simulate the transplantation microenvironment. We found that 3D culture of ADSCs triggered cell autophagy. After inhibiting autophagy by Chloroquine, the rates of apoptosis were increased. When the 3D ADSC-spheroids were re-planked, the number of senescent ADSCs decreased, and the proliferation ability was promoted. In addition, there were more cytokines secreted by 3D ADSC-spheroids including VEGF, IGF-1, and TGF-β. After adding the conditioned medium with human umbilical vein endothelial cells (HUVECs), 3D ADSC-spheroids were more likely to promote migration, and tube formation, stimulating the formation of new blood vessels. Fat grafting experiments in nude mice also showed that 3D ADSC-spheroids enhanced survival and neovascularization of fat grafts. These results suggested that 3D spheroids culturing of ADSCs can increase the therapeutic potential in fat transplantation.

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.

Supplementation of Facial Fat Grafting to Increase Volume Retention: A Systematic Review

BACKGROUND

For decades, facial fat grafting has been used in clinical practice for volume restoration. The main challenge of this technique is variable volume retention. The addition of supplements to augment fat grafts and increase volume retention has been reported in recent years.

OBJECTIVES

The aim of this systematic review was to investigate which supplements increase volume retention in facial fat grafting as assessed by volumetric outcomes and patient satisfaction.

METHODS

Embase, Medline, Ovid, Web of Science Core Collection, Cochrane Central Register of Controlled Trials, and Google Scholar were searched up to November 30, 2020. Only studies assessing volume after facial fat grafting with supplementation in human subjects were included. Outcomes of interest were volume or patient satisfaction. The quality of the studies was assessed with the Effective Public Health Practice Project tool.

RESULTS

After duplicates were removed 3724 studies were screened by title and abstract. After reading 95 full-text articles, 27 studies were eligible and included for comparison. Supplementation comprised of platelet-rich plasma, platelet-rich fibrin, adipose tissue-derived stromal cells or bone marrow-derived stromal cells, cellular or tissue stromal vascular fraction, or nanofat. In 13 out of 22 studies the supplemented group showed improved volumetric retention and 5 out of 16 studies showed greater satisfaction. The scientific quality of the studies was rated as weak for 20 of 27 studies, moderate for 6 of 27 studies, and strong for 1 study.

CONCLUSIONS

It remains unclear if additives contribute to facial fat graft retention and there is a need to standardize methodology.

LEVEL OF EVIDENCE: 4

The Effects of Shear Force-Based Processing of Lipoaspirates on White Adipose Tissue and the Differentiation Potential of Adipose Derived Stem Cells

Autologous lipotransfer is a promising method for tissue regeneration, because white adipose tissue contains a heterogeneous cell population, including mesenchymal stem cells, endothelial cells, immune cells, and adipocytes. In order to improve the outcome, adipose tissue can be processed before application. In this study, we investigated changes caused by mechanical processing. Lipoaspirates were processed using sedimentation, first-time centrifugation, shear-force homogenization, and second-time centrifugation. The average adipocyte size, stromal vascular cell count, and adipocyte depot size were examined histologically at every processing step. In addition, the adipose derived stem cells (ADSCs) were isolated and differentiated osteogenically and adipogenically. While homogenization causes a disruption of adipocyte depots, the shape of the remaining adipocytes is not changed. On average, these adipocytes are smaller than the depot adipocytes, they are surrounded by the ECM, and therefore mechanically more stable. The volume loss of adipocyte depots leads to a significant enrichment of stromal vascular cells such as ADSCs. However, the mechanical processing does not change the potential of the ADSCs to differentiate adipogenically or osteogenically. It thus appears that mechanically processed lipoaspirates are promising for the reparation of even mechanically stressed tissue as that found in nasolabial folds. The changes resulting from the processing correspond more to a filtration of mechanically less stable components than to a manipulation of the tissue.

Stromal vascular fraction improves the durability of autologous fat temple augmentation-A split-face randomized study using ultrasound biomicroscopy

BACKGROUND

Autologous lipotransfer aims to restore aging-associated volume loss, but with low predictability owing to 20-90% first-year loss of transferred fat. Enrichment by adipose-derived stem cells within the stromal vascular fraction (SVF) aims to improve volume retention through their differentiation potential and paracrine actions exerted by secreted trophic and angiogenic factors. Assessing studies lacked split-face designs, and used multitudes of enrichment ratios, preparation techniques and evaluation methods ending in contradictory reports regarding enrichment advantage.

AIM

To test whether enriching the autologous fat graft with SVF will increase its residual volume as compared to non-enriched graft. A standardized enrichment protocol and ratio and objective assessment were employed.

PATIENTS AND METHODS

In a split-face design, and after random assignment, bilateral temple augmentation using non-enriched versus SVF-enriched autologous lipotransfer were compared in middle-aged females otherwise healthy non-pregnant or breast-feeding females abstaining from esthetic or weight-controlling procedures. Temple volume scale (TVS), skin layers' thickness measured by ultrasound biomicroscopy (UBM), visual analog scale for patients' satisfaction, and side effects were blindly assessed at 1 week, 3 months, and 6 months.

RESULTS

In the included 15 females, TVS was significantly lower (0.5 ± 0.5 versus 1.1 ± 0.7, P = 0.0001), and% hypodermal augmentation was significantly higher (70.92 ± 58.09 versus 18.93 ± 19.33, P = 0.001) on the SVF-enriched side at 6 months. Patient satisfaction was similar bilaterally (P = 1), as were sequelae frequencies as lumping, edema, and ecchymosis.

CONCLUSION

SVF enrichment of transferred fat significantly improved its residual volume at 6 months; a conclusion that needs further validation. UBM was an informative objective tool for the following temple skin thickness changes. Trial registration clinical trials.gov (NCT03965936).

Fat Grafting: Basic Science, Techniques, and Patient Management

In this review, a summary of the rich history of autologous fat grafting is provided, and a comprehensive summary of the science and theory behind autologous adipocyte transplantation, as well as the techniques commonly used is described. These include recipient site preparation, harvesting, processing, and engraftment. In addition, important considerations for preoperative and postoperative management are discussed to maximize graft retention. Special considerations in grafting to the breast, face, and buttocks are also summarized.

Inhibition of RIP3 increased ADSC viability under OGD and modified the competency of adipogenesis, angiogenesis, and inflammation regulation

Adipose-derived stem cells (ADSCs) showed decreased cell viability and increased cell death under oxygen-glucose deprivation (OGD). Meanwhile, vital necroptotic proteins, including receptor-interacting protein kinase (RIP) 3 (RIP3) and mixed lineage kinase domain-like pseudokinase (MLKL), were expressed in the early stage. The present study aims to explore the effect of necroptosis inhibition on ADSCs. ADSCs were obtained from normal human subcutaneous fat and verified by multidirectional differentiation and flow cytometry. By applying cell counting kit-8 (CCK-8), calcein/propidium iodide (PI) staining and immunostaining, we determined the OGD treatment time of 4 h, a timepoint when the cells showed a significant decrease in viability and increased protein expression of RIP3, phosphorylated RIP3 (pRIP3) and phosphorylated MLKL (pMLKL). After pretreatment with the inhibitor of RIP3, necroptotic protein expression decreased under OGD conditions, and cell necrosis decreased. Transwell assays proved that cell migration ability was retained. Furthermore, the expression of the adipogenic transcription factor peroxisome proliferator-activated receptor γ (PPARγ) and quantitative analysis of Oil Red O staining increased in the inhibitor group. The expression of vascular endothelial growth factor-A (VEGFA) and fibroblast growth factor 2 (FGF2) and the migration test suggest that OGD increases the secretion of vascular factors, promotes the migration of human umbilical vein endothelial cells (HUVECs), and forms unstable neovascularization. ELISA revealed that inhibition of RIP3 increased the secretion of the anti-inflammatory factor, interleukin (IL)-10 (IL-10) and reduced the expression of the proinflammatory factor IL-1β. Inhibition of RIP3 can reduce the death of ADSCs, retain their migration ability and adipogenic differentiation potential, reduce unstable neovascularization and inhibit the inflammatory response.

Standardized Anatomic and Regenerative Facial Fat Grafting: Objective Photometric Evaluation 1 to 19 Months After Injectable Tissue Replacement and Regeneration

BACKGROUND

A standardized technique for facial fat grafting, injectable tissue replacement and regeneration (ITR2), incorporating new regenerative approaches, was developed to address anatomic volume losses in superficial and deep fat compartments as well as skin aging.

OBJECTIVES

The aim of this study was to track the short- and long-term effects of facial fat grafting by ITR2 in the midfacial zone over 19 months.

METHODS

Twenty-nine females were analyzed for midfacial volume changes after autologous fat transfer with ITR2 with varying fat parcel sizes. Volumes were evaluated with an imaging system to calculate differences between a predefined, 3-dimensional midfacial zone measured preoperatively and after fat grafting.

RESULTS

Patient data were analyzed collectively and by age (<55 and >55 years). Collective analysis revealed a trend of initial volume loss during Months 1 to 7 followed by an increase during Months 8 to 19, averaging 56.6% postoperative gain, and ending at an average of 52.3% gain in volume by 14 to 19 months. A similar trend was observed for patients <55 years of age, with a 54.1% average postoperative gain and a greater final average of 75.2%. Conversely, patients >55 years of age revealed a linear decay from 60.6% to 29.5%. Multiple regression analysis revealed no statistically significant influence of weight change throughout the study.

CONCLUSIONS

A dynamic change in facial volume was observed, with an initial decrease in facial volume followed by a rebound effect, by 19 months after treatment, of improved facial volume regardless of the amount of fat injected. Volume improvement was greater in patients <55 years old, whereas in patients >55 years old, volume gradually decreased. This study represents the first time that progressive improvement in facial volume has been shown 19 months after treatment.

LEVEL OF EVIDENCE: 4

Perforating Fat Injections for Chronic Plantar Fasciitis: A Randomized, Crossover Clinical Trial

SUMMARY

Plantar fasciitis affects 2 million patients per year. Ten percent of cases are chronic, with thickened plantar fascia. Treatment may lead to prolonged recovery, foot instability, and scar. The authors hypothesized that perforating fat injections would decrease plantar fascia thickness, reduce pain, and improve quality of life. Adults with plantar fascia greater than 4 mm for whom standard treatment had failed were included in a prospective, randomized, crossover pilot study. Group 1 (intervention) was followed for 12 months. Group 2 was observed for 6 months, injected, and then followed for 6 months. Validated patient reported outcome measures, ultrasound, and complications were assessed. Group 1 had nine female patients and group 2 had five patients. A total of 2.6 ± 1.6 ml of fat was injected per foot at one to two sites. In group 1, plantar fascia thickness decreased from screening at 6 and 12 months (p < 0.05). Group 2 had decreased plantar fascia thickness from screening to 6 months after injection (p < 0.05). Group 1 had pain improvements at 6 and 12 months compared with screening (p < 0.01). Group 2 reported no pain difference after injections (p > 0.05). Group 1 had improved activities of daily living and sports activity at 6 and 12 months compared with screening (p < 0.003). Group 2 noted increased sports activity 6 months after injection compared with screening (p < 0.03). In conclusion, perforating fat injections for chronic plantar fasciitis demonstrate significant improvement in pain, function, and plantar fascia thickness.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Safety of Aesthetic Medicine Procedures in Patients with Autoimmune Thyroid Disease: A Literature Review

Autoimmune thyroid diseases are the most common organ-specific autoimmune diseases, affecting 2–5% of the world’s population. Due to the autoimmune background of thyroid diseases, we analyzed a wide range of cosmetic procedures, from minimally invasive cosmetic injections (mesotherapy) to highly invasive procedures, such as lifting threads. Out of the seven categories of treatments in aesthetic medicine analyzed by us—hyaluronic acid, botulinum toxin, autologous platelet-rich plasma, autologous fat grafting, lifting threads, IPL and laser treatment and mesotherapy—only two, mesotherapy and lifting threads, are not recommended. This is due to the lack of safety studies and the potential possibility of a higher frequency of side effects in patients with autoimmune thyroid diseases.

Effectiveness of preconditioned adipose-derived mesenchymal stem cells with photobiomodulation for the treatment of diabetic foot ulcers: a systematic review

The primary goal of this systematic review article was to provide an outline of the use of diabetic autologous adipose-derived mesenchymal stem cells (DAAD-MSCs) in the treatment of wounds and ulcers in animal models and patients with diabetes mellitus (DM). The secondary goal was to present the outcomes of pretreatment of diabetic adipose-derived mesenchymal stem cells (DAD-MSCs) with probable different agents in the treatment of diabetic foot ulcers (DFUs) and wounds. In view of possible clinical applications of AD-MSC-mediated cell therapy for DFUs, it is essential to evaluate the influence of DM on AD-MSC functions. Nevertheless, there are conflicting results about the effects of DAAD-MSCs on accelerating wound healing in animals and DM patients. Multistep research of the MEDLINE, PubMed, Embase, Clinicaltrials.gov, Scopus database, and Cochrane databases was conducted for abstracts and full-text scientific papers published between 2000 and 2020. Finally, 5 articles confirmed that the usage of allogeneic or autologous AD-MSCs had encouraging outcomes on diabetic wound healing. One study reported that DM changes AD-MSC function and therapeutic potential, and one article recommended that the pretreatment of diabetic allogeneic adipose-derived mesenchymal stem cells (DAlD-MSCs) was more effective in accelerating diabetic wound healing. Recently, much work has concentrated on evolving innovative healing tactics for hastening the repair of DFUs. While DM alters the intrinsic properties of AD-MSCs and impairs their function, one animal study showed that the pretreatment of DAlD-MSCs in vitro significantly increased the function of DAlD-MSCs compared with DAlD-MSCs without any treatment. Preconditioning diabetic AD-MSCs with pretreatment agents like photobiomodulation (PBM) significantly hastened healing in delayed-healing wounds. It is suggested that further animal and human studies be conducted in order to provide more documentation. Hopefully, these outcomes will help the use of DAAD-MSCs plus PBM as a routine treatment protocol for healing severe DFUs in DM patients.

The Influence of High and Low Negative Pressure Liposuction and Various Harvesting Techniques on the Viability and Function of Harvested Cells-a Systematic Review of Animal and Human Studies

BACKGROUND

An understanding of fat grafting methodology, techniques and patient-related factors is crucial when considering fat grafting. Multiple factors can influence the success of a fat graft and consequently the outcome of the procedure. The aim of this systematic review is to elucidate the influence of negative pressure and various techniques of fat harvesting on the viability and function of cells, particularly adipocytes and adipose-derived stem cells.

METHODS

We conducted a literature search from 1975 to 2020 using the PubMed bibliography, ScienceDirect, SCOPUS and the Google Scholar databases which produced 168,628 articles on the first pass. After applying all the exclusion criteria by two independent reviewers, we were left with 21 articles (level IV of Oxford Centre for Evidence-Based Studies and Grade C of Grade Practice Recommendation from the American Society of Plastic Surgeons) on which this review is based.

RESULTS

From 11 studies focused on different negative pressures, no one found using high negative pressure advantageous. Summarising 13 studies focused on various harvesting techniques (excision, syringe, and pump-machine), most often equal results were reported, followed by excision being better than either syringe or liposuction.

CONCLUSION

From our systematic review, we can conclude that the low negative pressure seems to yield better results and that the excision seems to be the most sparing method for fat graft harvesting. However, we have to point out that this conclusion is based on a very limited number of statistically challengeable articles and we recommend well-conducted further research.

LEVEL OF EVIDENCE III

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 .

Changing the Paradigm of Craniofacial Reconstruction: A Prospective Clinical Trial of Autologous Fat Transfer for Craniofacial Deformities

OBJECTIVE

This study aimed to prospectively assess outcomes for surgical autologous fat transfer (AFT) applied for traumatic and postsurgical craniofacial deformities. The minimally invasive nature of AFT has potential for reduced risk and superior outcomes compared with current reconstructive options.

BACKGROUND

Craniofacial deformities have functional and psychosocial sequelae and can profoundly affect quality of life. Traditional reconstructive options are invasive, invasive, complex, and often lack precision in outcomes. Although AFT is safe, effective, and minimally invasive, only anecdotal evidence exists for reconstruction of craniofacial deformities.

METHODS

In this Institutional Review Board-approved prospective cohort study, 20 subjects underwent AFT (average volume: 23.9 ± 13.2 mL). Volume retention over time was determined using high-resolution computed tomography. Flow cytometry was used to assess cellular subpopulations and viability in the stromal vascular fraction. Quality of life assessments were performed. After the completion of 9-month follow-up, 5 subjects were enrolled for a second treatment.

RESULTS

No serious adverse events occurred. Volume retention averaged 63 ± 17% at 9 months. Three-month retention strongly predicted 9-month retention (r=0.996, P < 0.0001). There was no correlation between the total volume injected and retention. Patients undergoing a second procedure had similar volume retention as the first (P = 0.05). Age, sex, body mass index, and stromal vascular fraction cellular composition did not impact retention. Surprisingly, former smokers had greater volume retention at 9 months compared with nonsmokers (74.4% vs 56.2%, P = 0.009). Satisfaction with physical appearance (P = 0.002), social relationships (P = 0.02), and social functioning quality of life (P = 0.05) improved from baseline to 9 months.

CONCLUSIONS

For craniofacial defects, AFT is less invasive and safer than traditional reconstructive options. It is effective, predictable, and reaches volume stability at 3 months. Patient-reported outcomes demonstrate a positive life-changing impact.

Polydioxanone-Based Membranes for Bone Regeneration

Resorbable synthetic and natural polymer-based membranes have been extensively studied for guided tissue regeneration. Alloplastic biomaterials are often used for tissue regeneration due to their lower immunoreactivity when compared with allogeneic and xenogeneic materials. Plenum^® Guide is a synthetic membrane material based on polydioxanone (PDO), whose surface morphology closely mimics the extracellular matrix. In this study, Plenum^® Guide was compared with collagen membranes as a barrier material for bone-tissue regeneration in terms of acute and subchronic systemic toxicity. Moreover, characterizations such as morphology, thermal analysis (Tm = 107.35 °C and crystallinity degree = 52.86 ± 2.97 %, final product), swelling (thickness: 0.25 mm ≅ 436% and 0.5 mm ≅ 425% within 24 h), and mechanical tests (E = 30.1 ± 6.25 MPa; σ = 3.92 ± 0.28 MPa; ε = 287.96 ± 34.68%, final product) were performed. The in vivo results revealed that the PDO membranes induced a slightly higher quantity of newly formed bone tissue than the control group (score: treated group = 15, control group = 13) without detectable systemic toxicity (clinical signs and evaluation of the membranes after necropsy did not result in differences between groups, i.e., non-reaction -> tissue-reaction index = 1.3), showing that these synthetic membranes have the essential characteristics for an effective tissue regeneration. Human adipose-derived stem cells (hASCs) were seeded on PDO membranes; results demonstrated efficient cell migration, adhesion, spread, and proliferation, such that there was a slightly better hASC osteogenic differentiation on PDO than on collagen membranes. Hence, Plenum^® Guide membranes are a safe and efficient alternative for resorbable membranes for tissue regeneration.

Adipose Tissue-Derived Stem Cell Yield Depends on Isolation Protocol and Cell Counting Method

In plastic surgery, lipofilling is a frequent procedure. Unsatisfactory vascularization and impaired cell vitality can lead to unpredictable take rates in the fat graft. The proliferation and neovascularization inducing properties of adipose tissue-derived stem cells may contribute to solve this problem. Therefore, the enrichment of fat grafts with stem cells is studied intensively. However, it is difficult to compare these studies because many factors—often not precisely described—are influencing the results. Our study summarizes some factors which influence the cell yield like harvesting, isolation procedure and quantification. Stem cells were isolated after liposuction. Quantification was done using a cell chamber, colony counting, or flow cytometry with changes to one parameter, only, for each comparison. Quantification of cells isolated after liposuction at the same harvesting site from the same patient can vary greatly depending on the details of the isolation protocol and the method of quantification. Cell yield can be influenced strongly by many factors. Therefore, a comparison of different studies should be handled with care.

Human ESC-derived MSCs enhance fat engraftment by promoting adipocyte reaggregation, secreting CCL2 and mobilizing macrophages

Mesenchymal stem cells (MSCs) derived from somatic tissues have been used to promote lipotransfer, a common practice in cosmetic surgery. However, the effect of lipotransfer varies, and the mechanism of action remains vague. To address these questions, we differentiated human embryonic stem cells, a stable and unlimited source, into MSCs (EMSCs). Then we subcutaneously transplanted human fat aspirates together with EMSCs or PBS as a control into the back of nude mice. Within 24 h of transplantation, EMSCs promoted aggregation and encapsulation of injected fat tissues. Afterward, all grafts gradually shrank. However, EMSC-containing grafts were larger, heavier and had fewer dark areas on the surface than the control grafts. Histologically, more live adipocytes, vascular cells, and macrophages and less fibrosis were observed in EMSC-containing grafts than in the controls. Some EMSCs differentiated into vascular cells and adipocytes in the EMSC-containing grafts. RNA sequencing revealed that human RNA was shown to decline rapidly, while mouse RNA increased in the grafts; further, human genes related to extracellular matrix remodeling, adipogenesis, and chemokine (including CCL2) signaling were expressed at higher levels in the EMSC-containing grafts than they were in the controls. CCL2 knockout reduced macrophage migration towards EMSCs in vitro and early macrophage recruitment to the grafts and the pro-engraftment effect of EMSCs in vivo. Treating mice with a macrophage inhibitor abolished the EMSC effects and converted the grafts to heavy masses of cell debris. Together, these data demonstrate that EMSCs promote fat engraftment via enhanced tissue reconstitution and encapsulation of implanted tissues, which was followed by increased angiogenesis and adipocyte survival and reduced fibrosis, in which stimulated CCL2 signaling and mobilized macrophages play pivotal roles.

Human adipose-derived stem cells enriched with VEGF-modified mRNA promote angiogenesis and long-term graft survival in a fat graft transplantation model

Background

Fat grafting, as a standard treatment for numerous soft tissue defects, remains unpredictable and technique-dependent. Human adipose-derived stem cells (hADSCs) are promising candidates for cell-assisted therapy to improve graft survival. As free-living fat requires nutritional and respiratory sources to thrive, insufficient and unstable vascularization still impedes hADSC-assisted therapy. Recently, cytotherapy combined with modified mRNA (modRNA) encoding vascular endothelial growth factor (VEGF) has been applied for the treatment of ischemia-related diseases. Herein, we hypothesized that VEGF modRNA (modVEGF)-engineered hADSCs could robustly enhance fat survival in a fat graft transplantation model.

Methods

hADSCs were acquired from lipoaspiration and transfected with modRNAs. Transfection efficiency and expression kinetics of modRNAs in hADSCs were first evaluated in vitro. Next, we applied an in vivo Matrigel plug assay to assess the viability and angiogenic potential of modVEGF-engineered hADSCs at 1 week post-implantation. Finally, modVEGF-engineered hADSCs were co-transplanted with human fat in a murine model to analyze the survival rate, re-vascularization, proliferation, fibrosis, apoptosis, and necrosis of fat grafts over long-term follow-up.

Results

Transfections of modVEGF in hADSCs were highly tolerable as the modVEGF-engineered hADSCs facilitated burst-like protein production of VEGF in both our in vitro and in vivo models. modVEGF-engineered hADSCs induced increased levels of cellular proliferation and proangiogenesis when compared to untreated hADSCs in both ex vivo and in vivo assays. In a fat graft transplantation model, we provided evidence that modVEGF-engineered hADSCs promote the optimal potency to preserve adipocytes, especially in the long-term post-transplantation phase. Detailed histological analysis of fat grafts harvested at 15, 30, and 90 days following in vivo grafting suggested the release of VEGF protein from modVEGF-engineered hADSCs significantly improved neo-angiogenesis, vascular maturity, and cell proliferation. The modVEGF-engineered hADSCs also significantly mitigated the presence of fibrosis, apoptosis, and necrosis of grafts when compared to the control groups. Moreover, modVEGF-engineered hADSCs promoted graft survival and cell differentiation abilities, which also induced an increase in vessel formation and the number of surviving adipocytes after transplantation.

Conclusion

This current study demonstrates the employment of modVEGF-engineered hADSCs as an advanced alternative to the clinical treatment involving soft-tissue reconstruction and rejuvenation.

Ex vivo-expanded autologous adipose tissue-derived stromal cells ensure enhanced fat graft retention in breast augmentation: A randomized controlled clinical trial

Autologous fat grafting and implant surgery are used for volume restoration in plastic surgery. With the aim of producing a treatment superior to current solutions, we report a randomized, controlled, data assessor‐blinded clinical trial comparing fat grafts enriched with ex vivo‐expanded autologous adipose‐derived stromal cells (ASCs) to nonenriched fat grafts in breast augmentation. The intervention group received ASC‐enriched fat grafts (≥20 × 10⁶ viable ex vivo‐expanded ASCs per milliliter fat), and the control group received conventional nonenriched fat grafts. Volume retention was measured by magnetic resonance imaging, and clinical photographs were taken simultaneously for outcome evaluation. ASC‐enriched fat grafts had significantly higher retention rates (mean = 80.2%) compared with conventional fat grafts (mean = 45.1%). Clinical photos showed statistically significant superior results in the intervention group, assessed by independent clinical experts. These results improve the prospects for using culture‐expanded ASCs in both reconstructive and cosmetic volume restoration and make the procedure an attractive alternative to conventional fat grafting and implants. This study is registered at www.ClinicalTrials.gov, number H‐16046960.

Use of Buccal Fat Pad in the Treatment of Peri-Implant Mucosal Defect: A Case Report

The present study describes a clinical case in which the buccal fat pad (BFP) was used to improve the contour of the peri-implant mucosa. To our knowledge, this is the first case report of such an application in the literature. A 58-year-old woman presented with teeth #2 and #3 missing and an indication for extraction of tooth #4. After clinical examination and CBCT analysis, immediate implants were placed in the region of the extracted tooth and that of tooth #2 for prosthetic rehabilitation using a three-unit fixed partial denture. There was an extensive mucosal defect in the region of tooth #3, with vertical and horizontal changes in the contour of the mucosa. As an alternative to the use of a subepithelial connective tissue graft, we opted for displacement of the BFP and its accommodation on the alveolar ridge of tooth #3 to improve the buccal tissue contour. After 5 years of follow-up, satisfactory gain and maintenance of mucosal volume were observed in the treated area, as well as improvement of buccal tissue contour. The use of BFP seems to be a feasible alternative for filling and treating peri-implant mucosal defects.

Fat Therapeutics: The Clinical Capacity of Adipose-Derived Stem Cells and Exosomes for Human Disease and Tissue Regeneration

Fat grafting is a well-established surgical technique used in plastic surgery to restore deficient tissue, and more recently, for its putative regenerative properties. Despite more frequent use of fat grafting, however, a scientific understanding of the mechanisms underlying either survival or remedial benefits of grafted fat remain lacking. Clinical use of fat grafts for breast reconstruction in tissues damaged by radiotherapy first provided clues regarding the clinical potential of stem cells to drive tissue regeneration. Healthy fat introduced into irradiated tissues appeared to reverse radiation injury (fibrosis, scarring, contracture and pain) clinically; a phenomenon since validated in several animal studies. In the quest to explain and enhance these therapeutic effects, adipose-derived stem cells (ADSCs) were suggested as playing a key role and techniques to enrich ADSCs in fat, in turn, followed. Stem cells - the body's rapid response 'road repair crew' - are on standby to combat tissue insults. ADSCs may exert influences either by releasing paracrine-signalling factors alone or as cell-free extracellular vesicles (EVs, exosomes). Alternatively, ADSCs may augment vital immune/inflammatory processes; or themselves differentiate into mature adipose cells to provide the 'building-blocks' for engineered tissue. Regardless, adipose tissue constitutes an ideal source for mesenchymal stem cells for therapeutic application, due to ease of harvest and processing; and a relative abundance of adipose tissue in most patients. Here, we review the clinical applications of fat grafting, ADSC-enhanced fat graft, fat stem cell therapy; and the latest evolution of EVs and nanoparticles in healing, cancer and neurodegenerative and multiorgan disease.

Autologous fat graft assisted by stromal vascular fraction improves facial skin quality: A randomized controlled trial

BACKGROUND

Cell-assisted lipotransfer (CAL) promotes the survival of fat grafts with high vascular density and improves skin quality by increasing collagen content. However, no study has quantified the changes on the skin surface, and rigorous methodological evaluations are still lacking.

DESIGN

Fifty patients were recruited and randomly divided into two groups: an experimental group (n = 25) that underwent a stromal vascular fraction (SVF)-assisted fat graft and a control group (n = 25) that underwent fat graft only.

METHODS

The SVF cells were counted, tested in terms of viability, and characterized. The volumes of whole faces were determined by using a 3D scanner and Geomagic software preoperation, immediately after surgery, and 6 months postoperation. Facial skin qualities, including spots, wrinkles, texture, pores, UV spots, brown spots, red areas, and porphyrins, were detected by a VISIA skin detector preoperation and 6 months postoperation. A visual analog scale was used for clinical evaluation.

RESULTS

The cell pellet contained 1-3 × 10⁷/mL of fresh SVF cells. The cell viability exceeded 98%. The immunophenotyping characteristics and stemness were consistent with the features of adipose- derived stem cells (ADSCs). The survival rate of SVF-enriched fat grafts was significantly higher than that of control grafts: 77.6%±11.6% versus 56.2%±9.5% (p<0.001). The VISIA values of wrinkles (19.3 ± 6.6 versus 10.9 ± 5.5, p<0.001) and texture (15.8 ± 7.0 versus 10.3 ± 5.0, p<0.01) were significantly higher in SVF-enriched group than in control group at 6 months postoperation. During long-term follow-up, the majority of patients in both groups were satisfied with the final facial esthetic results.

CONCLUSIONS

Our results demonstrated the positive outcomes of autologous SVF-assisted fat graft in improving facial skin quality and its promising application potential in clinical settings. This study is registered at www. ClinicalTrials.gov, number NCT02923219.

The use of autologous fat grafts in breast surgery: A literature review

Autologous fat injection was first described roughly a century ago and has been used in surgery ever since. In addition to its use in many surgical fields, it is also frequently used for both aesthetic and reconstructive purposes in breast surgery. Since the application of fat grafting in breast surgery has steadily increased, studies investigating its reliability have simultaneously become increasingly common. Previous studies have reported that the use of fat grafting in breast surgery is reliable, but some pending questions remain about its routine use. In order to use fat grafts successfully in breast surgery, it is necessary to be familiar with the structure and content of adipose tissue, the efficacy of adipose stem cell-enriched fat grafts, the oncological safety of fat grafts, and the problems that may occur in the radiological follow-up of patients who undergo fat grafting procedures. In this literature review, we aim to discuss the use of fat grafts in breast surgery by investigating these common problems.

Heterogeneity in Adipose Stem Cells

Adipose stem cells (ASCs) are the basis of procedures intended for tissue regeneration. These cells are heterogeneous, owing to various factors, including the donor age, sex, body mass index, and clinical condition; the isolation procedure (liposuction or fat excision); the place from where the cells were sampled (body site and depth of each adipose depot); culture surface; type of medium (whether supplemented with fetal bovine serum or xeno-free), that affect the principal phenotypic features of ASCs. The features related to ASCs heterogeneity are relevant for the success of therapeutic procedures; these features include proliferation capacity, differentiation potential, immunophenotype, and the secretome. These are important characteristics for the success of regenerative tissue engineering, not only because of their effects upon the reconstruction and healing exerted by ASCs themselves, but also because of the paracrine signaling of ASCs and its impact on recipient tissues. Knowledge of sources of heterogeneity will be helpful in the standardization of ASCs-based procedures. New avenues of research could include evaluation of the effects of the use of more homo1geneous ASCs for specific purposes, the study of ASCs-recipient interactions in heterologous cell transplantation, and the characterization of epigenetic changes in ASCs, as well as investigations of the effect of the metabolome upon ASCs behavior in culture.

Regenerative Capacity of Adipose Derived Stem Cells (ADSCs), Comparison with Mesenchymal Stem Cells (MSCs)

Adipose tissue is now on the top one of stem cell sources regarding its accessibility, abundance, and less painful collection procedure when compared to other sources. The adipose derived stem cells (ADSCs) that it contains can be maintained and expanded in culture for long periods of time without losing their differentiation capacity, leading to large cell quantities being increasingly used in cell therapy purposes. Many reports showed that ADSCs-based cell therapy products demonstrated optimal efficacy and efficiency in some clinical indications for both autologous and allogeneic purposes, hence becoming considered as potential tools for replacing, repairing, and regenerating dead or damaged cells. In this review, we analyzed the therapeutic advancement of ADSCs in comparison to bone marrow (BM) and umbilical cord (UC)-mesenchymal stem cells (MSCs) and designed the specific requirements to their best clinical practices and safety. Our analysis was focused on the ADSCs, rather than the whole stromal vascular fraction (SVF) cell populations, to facilitate characterization that is related to their source of origins. Clinical outcomes improvement suggested that these cells hold great promise in stem cell-based therapies in neurodegenerative, cardiovascular, and auto-immunes diseases.

Regenerative Capacity of Adipose Derived Stem Cells (ADSCs), Comparison with Mesenchymal Stem Cells (MSCs)

Adipose tissue is now on the top one of stem cell sources regarding its accessibility, abundance, and less painful collection procedure when compared to other sources. The adipose derived stem cells (ADSCs) that it contains can be maintained and expanded in culture for long periods of time without losing their differentiation capacity, leading to large cell quantities being increasingly used in cell therapy purposes. Many reports showed that ADSCs-based cell therapy products demonstrated optimal efficacy and efficiency in some clinical indications for both autologous and allogeneic purposes, hence becoming considered as potential tools for replacing, repairing, and regenerating dead or damaged cells. In this review, we analyzed the therapeutic advancement of ADSCs in comparison to bone marrow (BM) and umbilical cord (UC)-mesenchymal stem cells (MSCs) and designed the specific requirements to their best clinical practices and safety. Our analysis was focused on the ADSCs, rather than the whole stromal vascular fraction (SVF) cell populations, to facilitate characterization that is related to their source of origins. Clinical outcomes improvement suggested that these cells hold great promise in stem cell-based therapies in neurodegenerative, cardiovascular, and auto-immunes 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.

Making Sense of Stem Cells and Fat Grafting in Plastic Surgery: The Hype, Evidence, and Evolving U.S. Food and Drug Administration Regulations

Autologous fat grafting and adipose-derived stem cells are two distinct entities with two different risk profiles, and should be regulated as such. Autologous fat grafting prepared with the additional step of stromal vascular fraction isolation is considered a form of "stem cell therapy" given the high concentration of stem cells found in stromal vascular fraction. Much ambiguity existed in the distinction between autologous fat grafting and stromal vascular fraction initially, in terms of both their biological properties and how they should be regulated. The market has capitalized on this in the past decade to sell unproven "stem cell" therapies to unknowing consumers while exploiting the regulatory liberties of traditional fat grafting. This led to a Draft Guidance from the U.S. Food and Drug Administration in 2014 proposing stricter regulations on fat grafting in general, which in turn elicited a response from plastic surgeons, who have safely used autologous fat grafting in the clinical setting for over a century. After a series of discussions, the U.S. Food and Drug Administration released its Final Guidance in November of 2017, which established clear distinctions between autologous fat grafting and stromal vascular fraction and their separate regulations. By educating ourselves on the U.S. Food and Drug Administration's final stance on fat grafting and stem cell therapy, we can learn how to navigate the regulatory waters for the two entities and implement their clinical use in a responsible and informed manner.

Argon plasma surface modification promotes the therapeutic angiogenesis and tissue formation of tissue-engineered scaffolds in vivo by adipose-derived stem cells

Background

Synthetic implants are being used to restore injured or damaged tissues following cancer resection and congenital diseases. However, the survival of large tissue implant replacements depends on their ability to support angiogenesis that if limited, causes extrusion and infection of the implant. This study assessed the beneficial effect of platelet-rich plasma (PRP) and adipose-derived stem cells (ADSCs) on synthetic biomaterials in combination with argon plasma surface modification to enhance vascularisation of tissue-engineered constructs.

Methods

Non-biodegradable polyurethane scaffolds were manufactured and modified with plasma surface modification using argon gas (PM). Donor rats were then used to extract ADSCs and PRP to modify the scaffolds further. Scaffolds with and without PM were modified with and without ADSCs and PRP and subcutaneously implanted in the dorsum of rats for 3 months. After 12 weeks, the scaffolds were excised and the degree of tissue integration using H&E staining and Masson’s trichrome staining, angiogenesis by CD31 and immune response by CD45 and CD68 immunohistochemistry staining was examined.

Results

H&E and Masson’s trichrome staining showed PM+PRP+ADSC and PM+ADSC scaffolds had the greatest tissue integration, but there was no significant difference between the two scaffolds (p < 0.05). The greatest vessel formation after 3 months was shown with PM+PRP+ADSC and PM+ADSC scaffolds using CD31 staining compared to all other scaffolds (p < 0.05). The CD45 and CD68 staining was similar between all scaffolds after 3 months showing the ADSCs or PRP had no effect on the immune response of the scaffolds.

Conclusions

Argon plasma surface modification enhanced the effect of adipose-derived stem cells effect on angiogenesis and tissue integration of polyurethane scaffolds. The combination of ADSCs and argon plasma modification may improve the survival of large tissue implants for regenerative applications.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1195-z) contains supplementary material, which is available to authorized users.

Regenerative and Transplantation Medicine: Cellular Therapy Using Adipose Tissue-Derived Mesenchymal Stromal Cells for Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is caused by the autoimmune targeting of pancreatic β-cells, and, in the advanced stage, severe hypoinsulinemia due to islet destruction. In patients with T1DM, continuous exogenous insulin therapy cannot be avoided. However, an insufficient dose of insulin easily induces extreme hyperglycemia or diabetic ketoacidosis, and intensive insulin therapy may cause hypoglycemic symptoms including hypoglycemic shock. While these insulin therapies are efficacious in most patients, some additional therapies are warranted to support the control of blood glucose levels and reduce the risk of hypoglycemia in patients who respond poorly despite receiving appropriate treatment. There has been a recent gain in the popularity of cellular therapies using mesenchymal stromal cells (MSCs) in various clinical fields, owing to their multipotentiality, capacity for self-renewal, and regenerative and immunomodulatory potential. In particular, adipose tissue-derived MSCs (ADMSCs) have become a focus in the clinical setting due to the abundance and easy isolation of these cells. In this review, we outline the possible therapeutic benefits of ADMSC for the treatment of T1DM.

Does Stromal Vascular Fraction Ensure a Higher Survival in Autologous Fat Grafting for Breast Augmentation? A Volumetric Study Using 3-Dimensional Laser Scanning

Background

Cell-assisted lipotransfer (CAL) has been considered a promising technique for promoting adipogenesis and angiogenesis in fat grafts.

Objectives

The author sought to objectively analyze the change of breast volume in patients who underwent stromal vascular fraction (SVF)-enriched fat grafting for breast augmentation and compared the clinical results with those who underwent conventional fat grafting without SVF by using 3-dimensional laser scanning.

Methods

From April 2015 to March 2016, 105 patients who underwent traditional fat grafting without SVF enrichment for breast augmentation were assigned to group A and served as the control. The other 101 patients who underwent SVF-enriched fat grafting for breast augmentation were assigned to group B. The charts of these patients were retrospectively reviewed.

Results

The survival rate of the transplanted fat was 67.9% in group A and 68.7% in group B at 12 months after the operation. Postoperative complication rate was 3.8% in group A and 5.9% in group B. The differences were statistically insignificant.

Conclusions

SVF does not ensure a higher survival rate in autologous fat grafting for breast augmentation. Considering the potential drawbacks of adipose-derived stem cells (ADSC) and the extra cost of the consumables, in particular the need for harvesting larger amount of fat which could be reserved for additional fat grafting at a later time to achieve even better improvement, the results of this study do not support the use of SVF in autologous fat grafting for breast augmentation in terms of graft survival and postoperative complications.

Level of Evidence 3

The use of fat grafting and platelet-rich plasma for wound healing: A review of the current evidence

Fat grafting is becoming a common procedure in regenerative medicine because of its high content of growth factors and adipose derived stem cells (ADSCs) and the ease of harvest, safety, and low cost. The high concentration of ADSCs found in fat has the potential to differentiate into a wide range of wound-healing cells including fibroblasts and keratinocytes as well as demonstrating proangiogenic qualities. This suggests that fat could play an important role in wound healing. However retention rates of fat grafts are highly variable due in part to inconsistent vascularisation of the transplanted fat. Furthermore, conditions such as diabetes, which have a high prevalence of chronic wounds, reduce the potency and regenerative potential of ADSCs. Platelet-rich plasma (PRP) is an autologous blood product rich in growth factors, cell adhesion molecules, and cytokines. It has been hypothesised that PRP may have a positive effect on the survival and retention of fat grafts because of improved proliferation and differentiations of ADSCs, reduced inflammation, and improved vascularisation. There is also increasing interest in a possible synergistic effect that PRP may have on the healing potential of fat, although the evidence for this is very limited. In this review, we evaluate the evidence in both in vitro and animal studies on the mechanistic relationship between fat and PRP and how this translates to a benefit in wound healing. We also discuss future directions for both research and clinical practice on how to enhance the regenerative potential of the combination of PRP and fat.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Strategic Design and Fabrication of Biomimetic 3D Scaffolds: Unique Architectures of Extracellular Matrices for Enhanced Adipogenesis and Soft Tissue Reconstruction

The higher rate of soft tissue impairment due to lumpectomy or other trauma greatly requires the restoration of the irreversibly lost subcutaneous adipose tissues. The nanofibers fabricated by conventional electrospinning provide only a superficial porous structure due to its sheet like 2D structure and thereby hinder the cell infiltration and differentiation throughout the scaffolds. Thus we developed a novel electrospun 3D membrane using the zwitterionic poly (carboxybetaine-co-methyl methacrylate) co-polymer (CMMA) through electrostatic repulsion based electrospinning for soft tissue engineering. The inherent charges in the CMMA will aid the nanofiber to directly transform into a semiconductor and thereby transfer the immense static electricity from the grounded collector and will impart greater fluffiness to the scaffolds. The results suggest that the fabricated 3D nanofiber (CMMA 3NF) scaffolds possess nanofibers with larger inter connected pores and less dense structure compared to the conventional 2D scaffolds. The CMMA 3NF exhibits significant cues of soft tissue engineering such as enhanced biocompatibility as well as the faster regeneration of cells. Moreover the fabricated 3D scaffolds greatly assist the cells to develop into its stereoscopic topographies with an enhanced adipogenic property.

Materials-Directed Differentiation of Mesenchymal Stem Cells for Tissue Engineering and Regeneration

Cell-based therapies are a promising alternative to grafts and organ transplantation for treating tissue loss or damage due to trauma, malfunction, or disease. Over the past two decades, mesenchymal stem cells (MSCs) have attracted much attention as a potential cell population for use in regenerative medicine. While the proliferative capacity and multilineage potential of MSCs provide an opportunity to generate clinically relevant numbers of transplantable cells, their use in tissue regenerative applications has met with relatively limited success to date apart from secreting paracrine-acting factors to modulate the defect microenvironment. Presently, there is significant effort to engineer the biophysical properties of biomaterials to direct MSC differentiation and further expand on the potential of MSCs in tissue engineering, regeneration, and repair. Biomaterials can dictate MSC differentiation by modulating features of the substrate including composition, mechanical properties, porosity, and topography. The purpose of this review is to highlight recent approaches for guiding MSC fate using biomaterials and provide a description of the underlying characteristics that promote differentiation toward a desired phenotype.

Effects of Collagenase Digestion and Stromal Vascular Fraction Supplementation on Volume Retention of Fat Grafts

OBJECTIVE

The use of autologous fat as a soft tissue filler has increased over the past decade in both reconstructive and aesthetic surgeries. Enhancement of autologous fat grafts with the addition of the stromal vascular fraction (SVF) has been reported to improve long-term volume retention. Stromal vascular fraction is most commonly isolated using enzymatic digestion, but it is unknown what effect the digestion process has on the adipocytes and SVF cells that comprise the graft. Some clinicians have reported use of enzymatically digested fat grafts to alter the physical properties of the tissue in specialized applications. We have previously reported that increasing collagenase digestion duration adversely affects the viability of adipocytes and SVF cells. Here, we aimed to determine if collagenase digestion of adipocytes before grafting is detrimental to long-term graft retention and if SVF supplementation can abrogate these potential deleterious effects.

METHODS AND RESULTS

We used a published xenograft model in which human lipoaspirate was implanted into the scalp of immunocompromised mice to study the effects of collagenase digestion on in vivo graft survival after 12 weeks. We used 4 experimental groups: grafts composed of collagenase-digested and nondigested adipocytes (50-minute digestion) and grafts with and without SVF supplementation. We used microcomputed tomography to serially and noninvasively quantify graft volume, in conjunction with hematoxylin-eosin staining of histological cross-sections of implanted and excised grafts to assess overall tissue viability. We found that adipocytes that were collagenase-digested before implantation had significantly lower retention rates at 12 weeks and poorer tissue health, which was assessed by quantifying the number of intact adipocytes, the number of cystic formations, and by scoring the degree of inflammation and fibrosis. Further, we found that SVF supplementation of the digested grafts improved graft survival, but not to the level observed in undigested grafts.

CONCLUSIONS

We conclude that collagenase digestion adversely affects the long-term volume retention of fat grafts, but that graft retention is improved by SVF supplementation. These experimental results can serve as an initial framework to further elucidate the reported efficacy and safety of using collagenase-digested fat grafts and SVF in the clinical setting.

Isolation and Flow Cytometric Analysis of the Stromal Vascular Fraction Isolated from Mouse Adipose Tissue

Evidence from preclinical research and clinical trials demonstrates the use of the stromal vascular fraction (SVF) as therapy for numerous indications. These results demonstrate that autologous SVF is not only safe and effective but provides robust anti-inflammatory, immunomodulatory, and reparative effects in vivo. The potency of the SVF is attributed to the cellular composition which includes adipose-derived stem cells (ASCs), adipocytes, endothelial cells, and various immune cells. As the name would suggest, these SVF cells are derived from the stromal compartment of adipose, or fat. Once digested, the cells that constitute adipose are released and collected as the SVF. The cellular frequencies within the SVF can then be assessed using a fluorescent antibody-based technique known as flow cytometry. The following chapter provides a standard operating protocol that describes the procedures from harvesting the fat tissue from experimental mice to isolating and characterizing the SVF.

Application of adipose-derived stromal cells in fat grafting: Basic science and literature review

Autologous fat is considered the ideal material for soft-tissue augmentation in plastic and reconstructive surgery. The primary drawback of autologous fat grafting is the high resorption rate. The isolation of mesenchymal stem cells from adipose tissue inevitably led to research focusing on the study of combined transplantation of autologous fat and adipose derived stem cells (ADSCs) and introduced the theory of ‘cell-assisted lipotransfer’. Transplantation of ADSCs is a promising strategy, due to the high proliferative capacity of stem cells, their potential to induce paracrine signalling and ability to differentiate into adipocytes and vascular cells. The current study examined the literature for clinical and experimental studies on cell-assisted lipotransfer to assess the efficacy of this novel technique when compared with traditional fat grafting. A total of 30 studies were included in the present review. The current study demonstrates that cell-assisted lipotransfer has improved efficacy compared with conventional fat grafting. Despite relatively positive outcomes, further investigation is required to establish a consensus in cell-assisted lipotransfer.

Historical Overview of Stem Cell Biology and Fat Grafting

The last two decades have seen significant advances within the field of adipose stromal cell transfers, with novel clinical applications being published every few months. This article gives a brief historical overview of the development of stem cell biology and fat grafting.

Systematic review of patient factors affecting adipose stem cell viability and function: implications for regenerative therapy

BACKGROUND

The applications for fat grafting have increased recently, within both regenerative and reconstructive surgery. Although fat harvesting, processing and injection techniques have been extensively studied and standardised, this has not had a big impact on the variability of outcome following fat grafting. This suggests a possible larger role of patient characteristics on adipocyte and adipose-derived stem cell (ADSC) viability and function. This systematic review aims to collate current evidence on the effect of patient factors on adipocyte and ADSC behaviour.

METHODS

A systematic literature review was performed using MEDLINE, Cochrane Library and EMBASE. It includes outcomes observed in in vitro analyses, in vivo animal studies and clinical studies. Data from basic science work have been included in the discussion to enhance our understanding of the mechanism behind ADSC behaviour.

RESULTS

A total of 41 papers were included in this review. Accumulating evidence indicates decreased proliferation and differentiation potential of ADSCs with increasing age, body mass index, diabetes mellitus and exposure to radiotherapy and Tamoxifen, although this was not uniformly seen across all studies. Gender, donor site preference, HIV status and chemotherapy did not show a significant influence on fat retention. Circulating oestrogen levels have been shown to support both adipocyte function and graft viability. Evidence so far suggests no significant impact of total cholesterol, hypertension, renal disease, physical exercise and peripheral vascular disease on ADSC yield.

CONCLUSIONS

A more uniform comparison of all factors highlighted in this review, with the application of a combination of tests for each outcome measure, is essential to fully understand factors that affect adipocyte and ADSC viability, as well as functionality. As these patient factors interact, future studies looking at adipocyte viability need to take them into consideration for conclusions to be meaningful. This would provide crucial information for surgeons when deciding appropriate volumes of lipoaspirate to inject, improve patient selection, and counsel patient expectations with regards to outcomes and likelihood for repeat procedures. An improved understanding will also assist in identification of patient groups that would benefit from graft enrichment and cryopreservation techniques.

Receptor for hyaluronan mediated motility (RHAMM/HMMR) is a novel target for promoting subcutaneous adipogenesis

Hyaluronan, CD44 and the Receptor for Hyaluronan-Mediated Motility (RHAMM, gene name HMMR) regulate stem cell differentiation including mesenchymal progenitor differentiation. Here, we show that CD44 expression is required for subcutaneous adipogenesis, whereas RHAMM expression suppresses this process. We designed RHAMM function blocking peptides to promote subcutaneous adipogenesis as a clinical and tissue engineering tool. Adipogenic RHAMM peptides were identified by screening for their ability to promote adipogenesis in culture assays using rat bone marrow mesenchymal stem cells, mouse pre-adipocyte cell lines and primary human subcutaneous pre-adipocytes. Oil red O uptake into fat droplets and adiponectin production were used as biomarkers of adipogenesis. Positive peptides were formulated in either collagen I or hyaluronan (Orthovisc) gels then assessed for their adipogenic potential in vivo following injection into dorsal rat skin and mammary fat pads. Fat content was quantified and characterized using micro CT imaging, morphometry, histology, RT-PCR and ELISA analyses of adipogenic gene expression. Injection of screened peptides increased dorsal back subcutaneous fat pad area (208.3 ± 10.4 mm²versus control 84.11 ± 4.2 mm²; p < 0.05) and mammary fat pad size (45 ± 11 mg above control background, p = 0.002) in female rats. This effect lasted >5 weeks as detected by micro CT imaging and perilipin 1 mRNA expression. RHAMM expression suppresses while blocking peptides promote expression of PPARγ, C/EBP and their target genes. Blocking RHAMM function by peptide injection or topical application is a novel and minimally invasive method for potentially promoting subcutaneous adipogenesis in lipodystrophic diseases and a complementary tool to subcutaneous fat augmentation techniques.

Mesenchymal Stem Cells from Adipose Tissue in Clinical Applications for Dermatological Indications and Skin Aging

Operating at multiple levels of control, mesenchymal stem cells from adipose tissue (ADSCs) communicate with organ systems to adjust immune response, provide signals for differentiation, migration, enzymatic reactions, and to equilibrate the regenerative demands of balanced tissue homeostasis. The identification of the mechanisms by which ADSCs accomplish these functions for dermatological rejuvenation and wound healing has great potential to identify novel targets for the treatment of disorders and combat aging. Herein, we review new insights into the role of adipose-derived stem cells in the maintenance of dermal and epidermal homeostasis, and recent advances in clinical applications of ADSCs related to dermatology.

In Vitro Effects of Adipose-Derived Stem Cells on Breast Cancer Cells Harvested From the Same Patient

INTRODUCTION

Fat grafting for breast cancer (BrCa) reconstruction and breast augmentation has become increasingly more popular. A major area of debate and controversy is the effect of adipose-derived stem cells (ASCs) on remnant or undetected BrCa cells. We investigate the in vitro response of BrCa to ASCs in a coculture model with regards to cell migration.

METHODS

The study was approved by the institutional review board. BrCa and adipose tissue specimens either from subcutaneous breast tissue or abdominal lipoaspirate were obtained from the same patient. BrCa cells and ASCs were harvested with either explant culture and/or enzymatic digestion. Tissues were grown in cell culture flasks until adequate cell libraries were established. Adipose-derived stem cells from adipose specimens were characterized with flow cytometry. Immunofluorescence (IF) staining of the initial cell population harvested from the BrCa specimens confirmed the presence of CD24, an epithelial marker of BrCa. A homogenous CD 24+/CD 90- BrCa cell population was obtained with flowcytometric cell sorting. The in vitro migration of BrCa cells was examined in coculture with and without ASCs.

RESULTS

Adipose-derived stem cells harvested from the adipose specimens were positive for mesenchymal stem cell markers CD 105, CD 90, CD 73, and CD 44 and negative for lymphocyte cell marker CD 34 and leukocyte marker CD 45. The percentage of the CD 24+/CD 90- BrCa cells in the initial cell population harvested from BrCa specimens was 0.61%. The BrCa cells morphologically had large nuclei and small cytoplasm in clusters under the light microscope, suggesting a cancer cell phenotype. CD 24 expression on the surface of BrCa cells was confirmed with IF staining. The number of BrCa cells migrated in ASCs coculture was approximately 10 times higher than the number of BrCa cells migrated in BrCa cell only cultures.

CONCLUSIONS

Adipose-derived stem cells significantly increase the migration capacity of BrCa cells in vitro in cocultures. This should be taken into consideration when performing fat grafting to the breast especially in patients with a history of BrCa or strong family history of BrCa.