Review: Proposed Methods to Improve the Survival of Adipose Tissue in Autologous Fat Grafting

Adipose-Derived Stromal Cell-Based Therapies for Radiation-Induced Fibrosis

Significance: Half of all cancer patients receive radiation therapy as a component of their treatment regimen, and the most common resulting complication is radiation-induced fibrosis (RIF) of the skin and soft tissue. This thickening of the dermis paired with decreased vascularity results in functional limitations and esthetic concerns and poses unique challenges when considering surgical exploration or reconstruction. Existing therapeutic options for RIF of the skin are limited both in scope and efficacy. Cell-based therapies have emerged as a promising means of utilizing regenerative cell populations to improve both functional and esthetic outcomes, and even as prophylaxis for RIF. Recent Advances: As one of the leading areas of cell-based therapy research, adipose-derived stromal cells (ADSCs) demonstrate significant therapeutic potential in the treatment of RIF. The introduction of the ADSC-augmented fat graft has shown clinical utility. Recent research dedicated to characterizing specific ADSC subpopulations points toward further granularity in understanding of the mechanisms driving the well-established clinical outcomes seen with fat grafting therapy. Critical Issues: Various animal models of RIF demonstrated improved clinical outcomes following treatment with cell-based therapies, but the cellular and molecular basis underlying these effects remains poorly understood. Future Directions: Recent literature has focused on improving the efficacy of cell-based therapies, most notably through (1) augmentation of fat grafts with platelet-rich plasma and (2) the modification of expressed RNA through epitranscriptomics. For the latter, new and promising gene targets continue to be identified which have the potential to reverse the effects of fibrosis by increasing angiogenesis, decreasing inflammation, and promoting adipogenesis.

Engineering 3D-Printed Bioresorbable Scaffold to Improve Non-Vascularized Fat Grafting: A Proof-of-Concept Study

Autologous fat grafting is the gold standard for treatment in patients with soft-tissue defects. However, the technique has a major limitation of unpredictable fat resorption due to insufficient blood supply in the initial phase after transplantation. To overcome this problem, we investigated the capability of a medical-grade poly L-lactide-co-poly ε-caprolactone (PLCL) scaffold to support adipose tissue and vascular regeneration. Deploying FDM 3D-printing, we produced a bioresorbable porous scaffold with interconnected pore networks to facilitate nutrient and oxygen diffusion. The compressive modulus of printed scaffold mimicked the mechanical properties of native adipose tissue. In vitro assays demonstrated that PLCL scaffolds or their degradation products supported differentiation of preadipocytes into viable mature adipocytes under appropriate induction. Interestingly, the chorioallantoic membrane assay revealed vascular invasion inside the porous scaffold, which represented a guiding structure for ingrowing blood vessels. Then, lipoaspirate-seeded scaffolds were transplanted subcutaneously into the dorsal region of immunocompetent rats (n = 16) for 1 or 2 months. The volume of adipose tissue was maintained inside the scaffold over time. Histomorphometric evaluation discovered small- and normal-sized perilipin+ adipocytes (no hypertrophy) classically organized into lobular structures inside the scaffold. Adipose tissue was surrounded by discrete layers of fibrous connective tissue associated with CD68+ macrophage patches around the scaffold filaments. Adipocyte viability, assessed via TUNEL staining, was sustained by the presence of a high number of CD31-positive vessels inside the scaffold, confirming the CAM results. Overall, our study provides proof that 3D-printed PLCL scaffolds can be used to improve fat graft volume preservation and vascularization, paving the way for new therapeutic options for soft-tissue defects.

Hybrid Stromal Vascular Fraction (Hybrid-SVF): A New Paradigm in Mechanical Regenerative Cell Processing

Enzymatic digestion of extracellular matrix (ECM) from lipoaspirate is the conventional form of harvesting stromal vascular fraction (SVF) called enzymatically digested SVF (E-SVF). Mechanical SVF (M-SVF) isolation has emerged as an alternative method, but it has also some limitations in terms of lower cell viability and diminished cell counts. To enhance the SVF qualitatively and quantitatively, we propose a novel concept called "hybrid-SVF," in which we combine M-SVF with the concentrated parts of adipose tissue after centrifugation, which is called stromal vascular matrix (SVM).

Methods

Hybrid-SVF injection was applied as an adjunctive therapy to fat grafting in 88 patients and 11 samples were evaluated in the laboratory for cell count, viability and cell activity.

Results

Experimental results determined that SVM part showed higher cellular activity. SVM and M-SVF showed higher cellular potency than E-SVF. Clinically, none of the patients required an additional session for fat grafting since there was no significant graft resorption. However, seven patients asked for further volume augmentation due to their individual preferences. No major complication was encountered.

Conclusions

The usage of hybrid-SVF has a very high regenerative potential due to the ECM support and exceptionally high cell yield in addition to preserved cell potency. Although there are ongoing studies focusing on optimizing cell counts and further clinical applications, we believe that our preliminary results might create a paradigm shift in the area of regenerative fat grafting.

The Utilization Of Poly-L-Lactic Acid As A Safe And Reliable Method For Volume Maintenance After Facelift Surgery With Fat Grafting

Background

For age-related volume loss, fat grafting is now recognized as an integral adjunctive procedure with facelift surgery. However, when there is continued and unpredicted volume loss postoperatively, the surgeon has limited options for restoring this lost volume.

Objectives

Poly-l-lactic acid (PLLA) is a proven biostimulator that creates volumetric enhancement. This study is undertaken to demonstrate that PLLA is a safe and efficacious option for maintenance of post-facelift volume loss.

Methods

A retrospective review was conducted to identify all patients who underwent facelift surgery with fat grafting and postoperative PLLA injections from 2010 to 2018 by a single surgeon. Demographic and clinical data were collected and analyzed.

Results

This review identified a total of 241 patients who had undergone a facelift with fat grafting and PLLA injections. Of these, 190 patients were treated with PLLA after facelift and fat grafting, while 51 patients received PLLA injections before their operation. We identified 5 common indications for use of PLLA after facelift surgery and fat grafting. These included unexplained early fat graft loss, significant weight loss in the postoperative period, normal aging process, and patients who had a high perioperative lean body mass. Additionally, PLLA was found to be an effective volumizer for site-specific areas that did not undergo fat grafting during the initial operation. There were no complications reported from the PLLA injections related to nodule formation, papules, or granulomas.

Conclusions

The high degree of variability in the survival of fat grafts with facelift surgery is an accepted reality. PLLA represents a safe and highly effective solution to restore volume loss in patients who have undergone facelifts with fat grafting.

The Effects of Vasonatrin Peptide on Fat Graft Viability: An Experimental Study

Vasonatrin peptide (VNP) is a synthetic peptide that possesses vasodilatory, natriuretic, and anti-inflammatory properties. The authors aimed to analyze the effects of VNP on fat graft survival. Twenty Sprague-Dawley rats are randomly divided into two groups of 10. Fat grafts are harvested from the right inguinal region. After preparation, fat grafts are placed to the interscapular region. The first group of rats were administered VNP after their fat injection, while the second group received tail-vein injections of an equal volume of sterile saline following their fat injection. Experiment and control groups are evaluated according to their level of degeneration of adipocytes, fat necrosis, vacuolization, cyst formation in adipocytes, fibrosis of the fat tissue, capillary density, and CD31 immunohistochemical staining. Degeneration, vacuolization, and cyst formation in adipocytes were lower in the experiment group. Increased capillary density in the experiment group was demonstrated by CD31 antibody staining and by counting capillary density under a microscope. The average percentage of change in weight of the fat grafts in the experiment group was lower than that in the control group. The results indicate that VNP has some beneficial effects on fat graft survival by multiple independent mechanisms that influence both local and systemic homeostasis.

'Fat chance': a review of adipose tissue engineering and its role in plastic and reconstructive surgery

Soft tissue reconstruction remains a continuing challenge for plastic and reconstructive surgeons. Standard methods of reconstruction such as local tissue transfer and free autologous tissue transfer are successful in addressing soft tissue cover, yet they do not come without the additional morbidity of donor sites. Autologous fat transfer has been used in reconstruction of soft tissue defects in different branches of plastic surgery, specifically breast and facial defect reconstruction, while further maintaining a role in body contouring procedures. Current autologous fat transfer techniques come with the drawbacks of donor-site morbidity and, more significantly, resorption of large amounts of fat. Advancement in tissue engineering has led to the use of engineered adipose tissue structures based on adipose-derived stem cells. This enables a mechanically similar reconstruct that is abundantly available. Cosmetic and mechanical similarity with native tissue is the main clinical goal for engineered adipose tissue. Development of novel techniques in the availability of natural tissue is an exciting prospect; however, it is important to investigate the potential of cell sources and culture strategies for clinical applications. We review these techniques and their applications in plastic surgery.

Comparison of the Effects of Repeated Applications of Platelet-Rich Plasma versus Platelet-Poor Plasma on Fat Graft Survival in Nude Mice

Autologous fat grafting has been widely used for soft tissue filling in plastic surgery. Platelet-rich plasma (PRP) could play a wide role in health and disease because of containing a variety of growth factors and cytokines. Although previous studies have described the positive effect of autologous PRP mixed with fat grafts, only minimal improvements in fat graft survival have been reported. The present study is aimed at comparing the effects of PRP and platelet-poor plasma (PPP) on the survival and quality of fat grafting. We built a 180-day nude mouse model implanted with a fat graft supplemented with PRP, PPP, or saline, respectively. The above reagents (PRP, PPP, or saline) were injected two additional times after the initial engraftment. The survival ratio of the fat grafts and the capillary density in the PRP group were significantly higher than those in the PPP group and the saline group (control group) at 15, 30, 90, and 180 days posttransplantation (P < 0.05). The survival ratio of the PPP group was higher than that of the saline group (P < 0.05), but the capillary density in the PPP group was not significantly different from that in the saline group at any time point (P > 0.05). We hence conclude that the repeated application of PRP or PPP three times can enhance the survival of fat grafts within 180 days. Moreover, the effect of PRP is superior to that of PPP.

Hirsutism Induced by Facial Autologous Fat Grafting

Autologous fat grafting (AFG) is a common procedure, which gains popularity for a large number of indications, mainly for reshaping and filling of contour defects. It is considered a safe procedure, with only uncommon and mild complications. Here we report on a 60-year-old female patient who developed excess hair growth on both cheeks 1 month following facial AFG done in conjunction with a facelift. Complete endocrine evaluation was within normal levels. Previous reports have suggested that adipocyte mesenchymal stem cells can secrete a number of growth factors, which in turn can lead to activation of stem cells in the hair follicle, affecting their growth. However, to the best of our knowledge, this is the first report on hirsutism as a side effect of AFG.

Autologous fat transfer for facial recontouring in Parry-Romberg syndrome

BACKGROUND

Parry-Romberg syndrome (PRS) is a rare condition involving self-limited progressive facial hemiatrophy.

AIMS

To analyze esthetic results of fat graft used for correcting soft-tissues atrophy in PRS patients, in the aspect of volume restoration and skin rejuvenation, to present our experience in redefining facial contours in PRS and modification of fat graft accusation technique (based on Coleman's technique).

PATIENTS/METHODS

A prospective evaluation study was designed to analyze esthetic results (contour and skin condition), complications, and subjective satisfaction of eight patients with PRS treated with fat graft.

RESULTS

All patients underwent two (n = 6) or three (n = 2) procedures in 3 months intervals (the mean 3.7 months). No major postoperative complications were observed. The authors evaluated their esthetic results concerning face contour and symmetry as good (in four patients) and very good (in four patients). Subjective assessment showed high patients' satisfaction with the final result of face contouring (the mean VAS [0-5]-4.75).

CONCLUSIONS

Our experience shows that fat grafting in patients with PRS is safe and gives satisfactory results in the aspect of volume restoration and skin quality improvement. Modified technique of graft preparation (112 g for 3 minutes) enables to obtain less dense fat graft, which is more appropriate in case of PRS patients with thin atrophic skin.

Aesthetic correction of lesion by post-liposuction corticoid infiltration using subcision, PMMA filling, and CO2 laser

INTRODUCTION

Post-liposuction fibrosis is a relatively common complication which can be repaired.

CASE REPORT

We report a case of cutaneous atrophy and diffuse irregularity of the abdominal region with achromia post-liposuction. She was treated with subcision, PMMA filler and fractioned CO2 laser.

RESULTS

Cutaneous colour and irregularities get improved.