Concise review: adipose-derived stromal vascular fraction cells and platelet-rich plasma: basic and clinical implications for tissue engineering therapies in regenerative surgery

Designed Surface Topographies Control ICAM-1 Expression in Tonsil-Derived Human Stromal Cells

Fibroblastic reticular cells (FRCs), the T-cell zone stromal cell subtype in the lymph nodes, create a scaffold for adhesion and migration of immune cells, thus allowing them to communicate. Although known to be important for the initiation of immune responses, studies about FRCs and their interactions have been impeded because FRCs are limited in availability and lose their function upon culture expansion. To circumvent these limitations, stromal cell precursors can be mechanotranduced to form mature FRCs. Here, we used a library of designed surface topographies to trigger FRC differentiation from tonsil-derived stromal cells (TSCs). Undifferentiated TSCs were seeded on a TopoChip containing 2176 different topographies in culture medium without differentiation factors, then monitored cell morphology and the levels of ICAM-1, a marker of FRC differentiation. We identified 112 and 72 surfaces that upregulated and downregulated, respectively, ICAM-1 expression. By monitoring cell morphology, and expression of the FRC differentiation marker ICAM-1 via image analysis and machine learning, we discovered correlations between ICAM-1 expression, cell shape and design of surface topographies and confirmed our findings by using flow cytometry. Our findings confirmed that TSCs are mechano-responsive cells and identified particular topographies that can be used to improve FRC differentiation protocols.

Accelerated healing of a diabetic foot ulcer using autologous stromal vascular fraction suspended in platelet-rich plasma

We describe the case of a Type I diabetic patient with a refractory foot ulcer that remained unhealed for 2 years despite conventional therapy. Autologous adipose-derived stromal vascular fraction suspended in autologous platelet-rich plasma was applied to the wound, which completely healed within 1 month. The wound remained closed with no complications for a 2-year follow-up. Reporting of this and similar cases may lead to larger clinical trials that will prove the efficacy of this therapy that may offer accelerated healing and lessen the financial burden of more expensive therapeutic modalities.

Effect of Use of Platelet-Rich Plasma (PRP) in Skin with Intrinsic Aging Process

BACKGROUND

In previous papers, we demonstrated that the treatment of human photoaged skin with stromal-vascular fraction-enriched fat or expanded adipose-derived stem cells showed a decrease of elastosis and the appearance of new oxytalan elastic fibers in dermis and an increase in the vascular network. The utilization of fat plus platelet-rich plasma (PRP) led to an increase in the vascular permeability and reactivity of the nervous component.

OBJECTIVES

The purpose of this study was to analyze the histologic and ultrastructural changes of human skin after the injection of only PRP in the retroauricular area that was not exposed to sun and did not present the photoaging process, in comparison with our previous results.

METHODS

This study was performed in 13 patients who were candidates for facelift and whose ages ranged between 45 and 65 years. The PRP injection was performed in the mastoidea area. Fragments of skin were removed before and 3 months after treatment and analyzed by optical and electron microscopy.

RESULTS

After the injection of PRP, we observed an increase of reticular dermis thickness because of the deposition of elastic fibers and collagen, with a fibrotic aspect. A modified pattern of adipose tissue was also found at the dermohypodermal junction. Significative regenerative aspects were not found at histologic and ultrastructural analysis. The presence of foci of moderate inflammation and microangiopathy were observed.

CONCLUSIONS

Treatment with PRP increased reticular dermis thickness with a fibrotic aspect. In the long term, the presence of inflammation and microangiopathy caused by PRP injection could lead to trophic alteration of the skin and the precocious aging process.

LEVEL OF EVIDENCE 4

Is Centrifugation Necessary for Processing Lipoaspirate Harvested via Water-Jet Force Assisted Technique before Grafting? Evidence of Lipoaspirate Concentration With Enhanced Fat Graft Survival

BACKGROUND

Although water-jet force-assisted liposuction technique (WAL) was demonstrated to have favorable effects on fat grafting, controversy continues concerning the application of centrifugation for lipoaspirate harvested via WAL. As a controversial technique, plastic surgeons often get perplexed to the necessity of using centrifugation during fat grafting procedure. In the present study, we adopted the recommended centrifugal intensity (1200g, 3 minutes) to process lipoaspirate and focused on the influence of centrifugation on the fate of lipoaspirate harvested with WAL technique.

METHODS

Lipoaspirate was obtained from 10 healthy Chinese female patients who underwent cosmetic liposuction. The harvested lipoaspirate was either not centrifuged (group A) or centrifuged at 1200g for 3 minutes (group B). Lipoaspirate from each group was compared in the in vitro and in vivo experiments. The influence of centrifugation on lipoaspirate viability and lipoaspirate survival after grafting were evaluated.

RESULTS

The viability of the lipoaspirates was similar between equally volumetric uncentrifugal and centrifugal lipoaspirate. However, centrifugation at 1200g for 3 minutes concentrated stromal vascular fraction cells and adipose-derived stem cells in lipoaspirate; greater angiogenesis and weight retention rates were observed in centrifugal lipoaspirate after grafting than those uncentrifugal lipoaspirate.

CONCLUSIONS

Centrifugation at 1200g for 3 minutes enhanced the survival of lipoaspirate harvested via WAL technique after grafting. Centrifugation at 1200g for 3 minutes was recommended to process lipoaspirate harvested with water-jet force assistance before grafting.

Regenerative Cells For Facial Surgery: Biofilling and Biocontouring

Zuk et al in 2001 identified stem and regenerative cells within the stromal vascular fraction of fat. In preclinical studies, these cells appeared to stimulate angiogenesis and reduce inflammation, and soon thereafter, clinical use of stromal vascular fraction (SVF) evolved as researchers such as Rigotti, Coleman, Mojallal, our group, and others demonstrated that fat can be used for both therapeutic and aesthetic indications. The regenerative effects of fat and its contents on facial aesthetics have been shown at the histologic and cellular level. Regeneration of elastin and collagen fibers as well as improvement in capillary density and reduction of inflammation have been reported. We review our current approach to the use of regenerative cells and different types of fat grafts in facial surgery. The fat graft is classified, both from a regenerative point of view as well as a tissue product that can be modified into different tissue characteristics, depending on the area and condition treated. Clinical use of SVF enriched fat, millifat, microfat, and nanofat grafts as well as composite fat grafts are reviewed. Based on clinical experience and evidence to date, it appears that the regenerative effects seen with the use of SVF in aesthetic surgery are modest, but there appear to be definite histologic findings of regeneration. These improvements may not be clinically apparent to a patient when cell enriched fat grafts are compared to fat grafts alone. However, the subtle changes seen in histology may be cumulative over time. Three types of fat grafts are defined: millifat (parcel size 2.4<), microfat (1.2<), and nanofat (400-600 μm). Each are characterized by their injectability ratings and emulsification parcel size as well as amount of sSVF cells. Newer concepts of periosteal fat grafting, buccal fat pad grafting, pyriform aperture fat grafting, intraorbital fat grafting, and nanofat grafting are discussed. Composite fat grafts are presented as a new concept as is biofilling and biocontouring. The use of regenerative cells in facial surgery is evolving rapidly. Our understanding of the anatomic changes that occur with aging has become more precise and our ability to target histologic changes seen with aging has become more effective. Deep fat compartment grafting, superficial fat grafting, nanofat, and SVF are becoming important components of contemporary facial rejuvenation. The use of regenerative approaches in facial rejuvenation is a logical step in changing the paradigm from surgical treatment of aging to a more proactive prevention and maintenance approach that keeps up with changes in the tissues as they age.

Short-term hypoxic preconditioning promotes prevascularization in 3D bioprinted bone constructs with stromal vascular fraction derived cells

Reconstruction of complex, craniofacial bone defects often requires autogenous vascularized bone grafts, and still remains a challenge today. In order to address this issue, we isolated the stromal vascular fraction (SVF) from adipose tissues and maintained the phenotypes and the growth of endothelial lineage cells within SVF derived cells (SVFC) by incorporating an endothelial cell medium. We 3D bioprinted SVFC within our hydrogel bioinks and conditioned the constructs in either normoxia or hypoxia. We found that short-term hypoxic conditioning promoted vascularization-related gene expression, whereas long-term hypoxia impaired cell viability and vascularization. 3D bioprinted bone constructs composed of polycaprolactone/hydroxyapatite (PCL/HAp) and SVFC-laden hydrogel bioinks were then implanted into athymic mice, after conditioning in normoxic or short-term hypoxic environments, in order to determine the in vitro and in vivo vascularization and osteogenic differentiation of the constructs. Short-term hypoxic conditioning promoted microvessel formation in vitro and in vivo and promoted integration with existing host vasculature, but did not affect osteogenic differentiation of SVFC. These findings demonstrate the benefit of short-term hypoxia and the potential for utilization of SVFC and 3D bioprinting for generating prevascularized 3D bioprinted bone constructs. Furthermore, the ability to custom design complex anatomical shapes has promising applications for the regeneration of both large and small craniofacial bone defects.

Adipose tissue stromal vascular fraction in the treatment of full thickness burns in rats

PURPOSE:

To analyze the healing effects of stromal vascular fraction (SVF) application compared to wound dressing with 2% silver sulfadiazine in full thickness burn wounds in rats.

METHODS:

Animals were divided into two groups: 2% silver sulfadiazine group and SVF group. Both groups received occlusive bandages while the first one was treated with 2% silver sulfadiazine and the latter was treated with injections of SVF prepared from adipose tissue extracted from an animal donor. The animals were accompanied through 3, 7 and 30 days for evaluation of macroscopic, microscopic and morphometric aspects.

RESULTS:

On day three, a significant increase (p<0.05) of infiltration of polymorphonuclear, fibrin formation and fibroblasts migration in SVF group was observed. On the 7th day the mononuclear infiltrate, angiogenesis, collagen and fibroblasts were significantly increased in the SVF group (p<0.05). At 30 days significantly increased collagen deposition was observed in the SVF group (p<0.05) .

CONCLUSION:

Adipose tissue derived stromal vascular fraction injections promotes better wound repair than 2% silver sulfadiazine in the treatment of full thickness burn in rats during the evaluated experimental period.

Isolation, Primary Culture, and Differentiation of Preadipocytes from Mouse Brown Adipose Tissue

Evolutionally, brown adipose tissue (BAT) is developed for nonshivering thermogenesis to prevent hypothermia. BAT has a high capacity to dissipate chemical energy generated from metabolism of nutrients for heat production. Therefore when BAT is activated, nutrients are "burned' instead of being stored. This feature makes BAT an attractive target for obesity treatment. To investigate BAT function and regulation, brown adipocyte culturing is indispensable. This chapter describes a detailed protocol for isolation, primary culture, and differentiation of preadipocytes from mouse BAT. The preadipocytes can be used for investigating the regulation of brown fat cell differentiation. The differentiated brown adipocytes maintain major BAT features including high expression of uncoupling protein-1 and can be used to study BAT biology and pharmacology.

Reconstruction of Alar Nasal Cartilage Defects Using a Tissue Engineering Technique Based on a Combined Use of Autologous Chondrocyte Micrografts and Platelet-rich Plasma: Preliminary Clinical and Instrumental Evaluation

Background:

Developing cartilage constructs with injectability, appropriate matrix composition, and persistent cartilaginous phenotype remains an enduring challenge in cartilage repair. The combined use of autologous chondrocyte micrografts and platelet-rich plasma (PRP) is an alternative that opens a new era in this field.

Methods:

At the Department of Plastic and Reconstructive Surgery, University of Rome Tor Vergata, Italy, 11 patients underwent nasal alar reconstruction with chondrocyte micrografts gently poured onto PRP in solid form. A computed tomographic scan control was performed after 12 months. Pearson’s Chi-square test was used to investigate difference in cartilage density between native and newly formed cartilages.

Results:

The constructs of chondrocyte micrografts–PRP that were subcutaneously injected resulted in a persistent cartilage tissue with appropriate morphology, adequate central nutritional perfusion without central necrosis or ossification, and further augmented nasal dorsum without obvious contraction and deformation.

Conclusion:

This report demonstrated that chondrocyte micrografts derived from nasal septum poured onto PRP in solid form are useful for cartilage regeneration in patients with external nasal valve collapse.

Concise Review: The Use of Adipose-Derived Stromal Vascular Fraction Cells and Platelet Rich Plasma in Regenerative Plastic Surgery

Tissue engineering has emerged at the intersection of numerous disciplines to meet a global clinical need for technologies to promote the regeneration of tissues. Recently, many authors have focused their attention on mesenchymal stem/stromal cells (MSCs) for their capacity to differentiate into many cell lineages. The most widely studied cell types are bone marrow mesenchymal stem cells and adipose-derived stem cells (ASCs), which display similar results. Biomaterials, cells, and growth factors are needed to design a regenerative plastic surgery approach in the treatment of organ and tissue defects, but not all tissues are created equal. The aim of this article is to describe the advances in tissue engineering through the use of ASCs, platelet rich plasma, and biomaterials to enable regeneration of damaged complex tissue. Stem Cells 2017;35:117-134.

Evaluation of adipose-derived stromal vascular fraction from the lateral tailhead, inguinal region, and mesentery of horses

Use of mesenchymal stem cells (MSCs) found in the stromal vascular fraction (SVF) of equine adipose tissue has promising applications for regenerative therapies. The most commonly used source of equine adipose tissue is the subcutaneous tailhead. The objective of this study was to compare 3 adipose depot sites in horses and determine the viability and cellular yield, capillary density, gene expression for selected markers, and colony-forming unit fibroblasts (CFU-Fs) in adipose tissue taken from these sites. Adipose tissue was excised from the area lateral to the tailhead, the inguinal region, and the small colon mesentery of 6 horses. Lipoaspirate was also collected from the area lateral to the tailhead. Stromal vascular fraction (SVF) was prepared in duplicate from the 3 different adipose tissue depots. The total nucleated and dead cell counts was determined manually using a hemocytometer and percent viability was calculated. Mass and volume of adipose were determined in order to calculate density and factor-VIII immunohistochemical staining was used to determine vascular density in the excisional adipose tissue samples from each horse. Quantitative polymerase chain reaction (qPCR) was used to quantify gene expression for selected cellular markers from each site. There were significant differences in viability, yield of nucleated cells/gram of adipose tissue, vascular density, gene expression, and CFU-Fs among adipose depots. Adipose from the mesentery yielded the highest number of nucleated cells/gram of tissue and the highest vascular density and percentage of CFU-Fs. In the horse, both the anatomical site of collection and the method of tissue collection significantly impact the yield and composition of cells in the SVF. Further study is needed to assess whether one adipose source is superior for harvesting mesenchymal stem cells (MSCs) and whether the differences among sources are clinically relevant for in-vivo treatment of musculoskeletal injuries in horses.

Effects of platelet-rich plasma in a model of bovine endometrial inflammation in vitro

BACKGROUND

Endometritis reduces fertility and is responsible for major economic losses in beef and dairy industries. The aim of this study was to evaluate an alternative therapy using platelet-rich plasma (PRP). PRP was tested in vivo, after bovine intrauterine administration, and in vitro on endometrial cells.

METHODS

Bovine endometrial cells were cultured until passage (P) 10 with 5 % or 10 % PRP. Effect of PRP on endometrial cell proliferation and on the expression of genes [prostaglandin-endoperoxide synthase 2 (COX2), tumor protein p53 (TP53), oestrogen receptors (ER-α and ER-β), progesterone receptor (PR) and c-Myc] involved in the regulation of oestrus cycle and fetal-maternal interaction were evaluated. Moreover, to evaluate the ability of PRP to counteract inflammation, 10 and 100 ng/ml of bacterial endotoxin lipopolysaccharide (LPS) were used to inflame endometrial cells in vitro for 1, 6, 12, 24 and 48 h. The expression of genes such as interleukin 1β (IL-1β), interleukin-8 (IL-8), inducible nitric oxide synthase (iNOS), prostaglandin-endoperoxide synthase 2 (COX2/PTGS2), and the release of PGE-2, IL-1β and IL-8 were evaluated.

RESULTS

In vivo treatment with PRP increased the detection of PR. In vitro, 5 % PRP at passage 5 increased proliferation rate and induced a significant increase in the expression of all studied genes. Furthermore, the results revealed that 10 ng/ml of LPS is the most effective dose to obtain an inflammatory response, and that PRP treatment significantly down regulated the expression of pro-inflammatory genes.

CONCLUSION

This study lays the foundations for the potential treatment of endometritis with PRP in vivo.

Platelet-rich plasma (PRP) and adipose-derived mesenchymal stem cells: stimulatory effects on proliferation and migration of fibroblasts and keratinocytes in vitro

The clinical use of tissue engineering associated with cell therapy is considered a new alternative therapy for the repair of chronic lesions with potential application in different medical areas, mostly in orthopedic and dermatological diseases. Platelet-rich plasma (PRP) is a rich source of growth factors and cytokines important for wound healing. Adipose-derived mesenchymal stem cells (ADSCs) have shown potential to accelerate the resolution of ulcers, to stimulate cell proliferation, and to benefit the quality of skin repair. This study aims to determine the effect of PRP and conditioned medium (CM) from ADSC on fibroblast and keratinocyte proliferation in vitro. Migration and proliferation assays were performed to evaluate the growth of fibroblasts and keratinocytes in the presence of PRP, CM, and CM + PRP. Significant proliferative stimulation was observed after 48 h of culture (p < 0.05) on mean absorbance of fibroblasts cultured with 10 and 25 % PRP, 100 % CM, and 25 % PRP + 25 % CM, if compared with control. Keratinocyte proliferation was stimulated after 48 h in cultures with 25, 50, and 100 % CM, and growth was compared with controls. The migration assay detected a significant migratory stimulus in fibroblasts cultured with 10 % PRP + 10 % CM after 48 h. These in vitro results suggest that PRP and ADSC have therapeutic potential for healing and re-epithelialization of chronic wounds in vivo.

Platelet-Rich Plasma Influences Expansion and Paracrine Function of Adipose-Derived Stromal Cells in a Dose-Dependent Fashion

BACKGROUND

Lipofilling is a treatment modality to restore tissue volume. Both platelet-rich plasma and adipose-derived stromal cells have been reported to augment the efficacy of lipofilling, yet results are not conclusive. The authors hypothesized that the variation reported in literature is caused by a dose-dependent influence of platelet-rich plasma on adipose-derived stromal cells.

METHODS

Whole blood (n = 3) was used to generate platelet-rich plasma, which was diluted with Dulbecco's Modified Eagle Medium to 15%, 5%, and 1.7%, with 15% platelet-poor plasma and 10% fetal calf serum as controls. Pooled adipose-derived stromal cells (n = 3) were cultured in these media. Gene expression was assessed, along with angiogenic sprouting of endothelial cells by conditioned medium and platelet-rich plasma.

RESULTS

platelet-rich plasma in culture medium affected the expression of genes in a dose-dependent manner. The 15% concentration stimulated proliferation almost eightfold. Mesenchymal markers were unaffected. Interestingly, expression of collagens type 1 and 3 increased at lower concentrations, whereas transforming growth factor-β showed reduced expression in lower concentrations. Proangiogenic gene expression was unaltered or strongly reduced in a dose-dependent manner. platelet-rich plasma promoted endothelial sprouting and survival in a dose-dependent manner; however, conditioned medium from adipose-derived stromal cells exposed to platelet-rich plasma blocked endothelial sprouting capabilities.

CONCLUSION

The dose-dependent influence of platelet-rich plasma on the therapeutic capacity of adipose-derived stromal cells conditioned medium in vitro warrants caution in clinical trials.

Adipose-Derived Regenerative Cell Therapy for Burn Wound Healing: A Comparison of Two Delivery Methods

Objective: The use of noncultured autologous stromal vascular fraction or clinical grade adipose-derived regenerative cells (ADRCs) is a promising strategy to promote wound healing and tissue repair. Nevertheless, issues regarding the optimal mode of administration remain unclear. The purpose of this study was to compare the effects of local injection and topical spray delivery of ADRCs in a porcine model of thermal burns. Approach: Full-thickness thermal burns were created on the dorsum of 10 Gottingen minipigs. Two days following injury, wounds underwent fascial excision and were randomized to receive control vehicle or freshly isolated autologous ADRCs delivered by either multiple injections into or surrounding the wound bed, or by spray onto the wound surface (0.25 × 10⁶ viable cells/cm²). Healing was evaluated by planimetry, histopathology, and immunohistochemistry at day 7, 12, 16, 21, and 28 posttreatment. Results:In vitro analysis demonstrated that there was no substantial loss of cell number or viability attributable to the spray procedure. Planimetric assessment revealed that delivery of ADRCs by either local injection or topical spray increased wound reepithelialization relative to control at day 14. No significant difference in wound reepithelialization was observed between both delivery approaches. In addition, on day 7 posttreatment, blood vessel density was greater in wounds receiving local or topical spray ADRCs than in the wounds treated with vehicle control. Histopathologic analysis suggests that ADRC treatment may modulate the inflammatory response by reducing neutrophil infiltration at day 7 and 12 posttreatment, irrespective of the route of administration. Conclusions: These data demonstrate that local injection and spray delivery of ADRCs modulate inflammation and improve wound angiogenesis and epithelialization. Importantly, both delivery routes exhibited similar effects on wound healing. Given the greater ease-of-use associated with topical spray delivery, these data support the use of a spray system for autologous ADRC delivery.

Preischemic Administration of Nonexpanded Adipose Stromal Vascular Fraction Attenuates Acute Renal Ischemia/Reperfusion Injury and Fibrosis

: Ischemia/reperfusion (IR)-induced acute kidney injury (AKI) is a common clinical syndrome. Stem/progenitor cell therapy is a promising option to foster the intrinsic capacity for kidney regeneration. However, there are still several challenges to be resolved, including the potential risks during cell culture, low retention rate after transplantation, and unclear effect on the progression of chronic kidney disease (CKD). Recently, nonexpanded adipose stromal vascular fraction (SVF) has been regarded as an attractive cell source for cell-based therapy. Preconditioning with ischemia has been suggested as a useful method to promote the retention and survival of transplanted cells in vivo. In this study, freshly isolated autologous SVF was transplanted to the kidney of rats before ischemia, and then an IR-induced AKI model was established. Postischemic administration of SVF to the kidney was performed after renal IR injury was induced. A higher cell retention rate was detected in the preischemic group. Preischemic administration of SVF showed stronger functional and morphologic protection from renal IR injury than postischemic administration, through enhancing tubular cell proliferation and reducing apoptosis. Progression of kidney fibrosis was also significantly delayed by preischemic administration of SVF, which exhibited stronger inhibition of transforming growth factor-β1-induced epithelia-mesenchymal transition and microvascular rarefaction. In addition, in vitro study showed that prehypoxic administration of SVF could significantly promote the proliferation, migration, and survival of hypoxic renal tubular epithelial cells. In conclusion, our study demonstrated that preischemic administration of nonexpanded adipose SVF protected the kidney from both acute IR injury and long-term risk of developing CKD.

SIGNIFICANCE

Renal ischemia/reperfusion (IR) injury is a common clinical syndrome. Cell-based therapy provides a promising option to promote renal repair after IR injury. However, several challenges still remain because of the potential risks during cell culture, low retention rate after transplantation, and unclear effect on the progression of chronic kidney disease. Stromal vascular fraction (SVF) is considered as an attractive cell source. This study demonstrated that preischemic administration of uncultured SVF could increase cell retention and then improve renal function and structure at both early and long-term stage after IR, which may provide a novel therapeutic approach for IR injury.

Stem Cells in Skin Wound Healing: Are We There Yet?

Significance: Cutaneous wound healing is a serious problem worldwide that affects patients with various wound types, resulting from burns, traumatic injuries, and diabetes. Despite the wide range of clinically available skin substitutes and the different therapeutic alternatives, delayed healing and scarring are often observed. Recent Advances: Stem cells have arisen as powerful tools to improve skin wound healing, due to features such as effective secretome, self-renewal, low immunogenicity, and differentiation capacity. They represent potentially readily available biological material that can particularly target distinct wound-healing phases. In this context, mesenchymal stem cells have been shown to promote cell migration, angiogenesis, and a possible regenerative rather than fibrotic microenvironment at the wound site, mainly through paracrine signaling with the surrounding cells/tissues. Critical Issues: Despite the current insights, there are still major hurdles to be overcome to achieve effective therapeutic effects. Limited engraftment and survival at the wound site are still major concerns, and alternative approaches to maximize stem cell potential are a major demand. Future Directions: This review emphasizes two main strategies that have been explored in this context. These comprise the exploration of hypoxic conditions to modulate stem cell secretome, and the use of adipose tissue stromal vascular fraction as a source of multiple cells, including stem cells and factors requiring minimal manipulation. Nonetheless, the attainment of these approaches to target successfully skin regeneration will be only evident after a significant number of in vivo works in relevant pre-clinical models.

Expanded Stem Cells, Stromal-Vascular Fraction, and Platelet-Rich Plasma Enriched Fat: Comparing Results of Different Facial Rejuvenation Approaches in a Clinical Trial

BACKGROUND

In a previous study, the authors demonstrated that treatment with expanded adipose-derived stem cells or stromal vascular fraction (SVF)-enriched fat modify the pattern of the dermis in human beings, representing a skin rejuvenation effect. Considering that expanded stem cells require a cell factor, the authors wanted to assess similar results by replacing them with platelet-rich plasma (PRP), which is easier to obtain and for which an empirical regenerative effect has been already described.

OBJECTIVES

To determine if PRP injection could replace the cutaneous regenerative effect of adipose-derived stem cells.

METHODS

This study was performed in 13 patients who were candidates for facelift. The patients underwent sampling of fat by liposuction from the abdomen and submitted to one of three protocols: injection of SVF-enriched fat or expanded adipose-derived stem cells or fat plus PRP in the preauricular areas. Fragments of skin were removed before and 3 months after treatment and analyzed by optical and electron microscopy.

RESULTS

The use of fat plus PRP led to the presence of more pronounced inflammatory infiltrates and a greater vascular reactivity, increasing in vascular permeability and a certain reactivity of the nervous component. The addition of PRP did not improve the regenerative effect.

CONCLUSION

The use of PRP did not have significant advantages in skin rejuvenation over the use of expanded adipose-derived stem cells or SVF-enriched fat. The effect of increased vascular reactivity may be useful in pathological situations in which an intense angiogenesis is desirable, such as tissular ischemia.

Advancing biomaterials of human origin for tissue engineering

Biomaterials have played an increasingly prominent role in the success of biomedical devices and in the development of tissue engineering, which seeks to unlock the regenerative potential innate to human tissues/organs in a state of deterioration and to restore or reestablish normal bodily function. Advances in our understanding of regenerative biomaterials and their roles in new tissue formation can potentially open a new frontier in the fast-growing field of regenerative medicine. Taking inspiration from the role and multi-component construction of native extracellular matrices (ECMs) for cell accommodation, the synthetic biomaterials produced today routinely incorporate biologically active components to define an artificial in vivo milieu with complex and dynamic interactions that foster and regulate stem cells, similar to the events occurring in a natural cellular microenvironment. The range and degree of biomaterial sophistication have also dramatically increased as more knowledge has accumulated through materials science, matrix biology and tissue engineering. However, achieving clinical translation and commercial success requires regenerative biomaterials to be not only efficacious and safe but also cost-effective and convenient for use and production. Utilizing biomaterials of human origin as building blocks for therapeutic purposes has provided a facilitated approach that closely mimics the critical aspects of natural tissue with regard to its physical and chemical properties for the orchestration of wound healing and tissue regeneration. In addition to directly using tissue transfers and transplants for repair, new applications of human-derived biomaterials are now focusing on the use of naturally occurring biomacromolecules, decellularized ECM scaffolds and autologous preparations rich in growth factors/non-expanded stem cells to either target acceleration/magnification of the body's own repair capacity or use nature's paradigms to create new tissues for restoration. In particular, there is increasing interest in separating ECMs into simplified functional domains and/or biopolymeric assemblies so that these components/constituents can be discretely exploited and manipulated for the production of bioscaffolds and new biomimetic biomaterials. Here, following an overview of tissue auto-/allo-transplantation, we discuss the recent trends and advances as well as the challenges and future directions in the evolution and application of human-derived biomaterials for reconstructive surgery and tissue engineering. In particular, we focus on an exploration of the structural, mechanical, biochemical and biological information present in native human tissue for bioengineering applications and to provide inspiration for the design of future biomaterials.

Autologous staged fat tissue transfer in post-traumatic lower extremity reconstruction

Autologous fat tissue transfer for aesthetic reconstruction has been described in the literature for soft tissue damage as early as 1893. One area that has yet to be described is the role of fat grafting in post-traumatic lower extremity injuries. In this case report, we present a patient who had significant injury to her right lower extremity and presented for reconstruction. The patient is a 52-year-old female who presented to clinic after a right lower extremity traumatic injury that required multiple re-operations, which lead to dense scarring and volume loss along the extremity inferior to the knee joint. The patient received two staged autologous fat injections and reported positive outcomes. Our case report demonstrates the utility of fat transfer in reconstruction of the lower extremity in staged fashion. Further research in the refinement of this technique and patient follow-up will lead to better graft survival and reconstructive outcomes.

Fluorine-19 Labeling of Stromal Vascular Fraction Cells for Clinical Imaging Applications

Stromal vascular fraction (SVF) cells are used clinically for various therapeutic targets. The location and persistence of engrafted SVF cells are important parameters for determining treatment failure versus success. We used the GID SVF-1 platform and a clinical protocol to harvest and label SVF cells with the fluorinated ((19)F) agent CS-1000 as part of a first-in-human phase I trial (clinicaltrials.gov identifier NCT02035085) to track SVF cells with magnetic resonance imaging during treatment of radiation-induced fibrosis in breast cancer patients. Flow cytometry revealed that SVF cells consisted of 25.0% ± 15.8% CD45+, 24.6% ± 12.5% CD34+, and 7.5% ± 3.3% CD31+ cells, with 2.1 ± 0.7 × 10⁵ cells per cubic centimeter of adipose tissue obtained. Fluorescent CS-1000 (CS-ATM DM Green) labeled 87.0% ± 13.5% of CD34+ progenitor cells compared with 47.8% ± 18.5% of hematopoietic CD45+ cells, with an average of 2.8 ± 2.0 × 10¹² ¹⁹F atoms per cell, determined using nuclear magnetic resonance spectroscopy. The vast majority (92.7% ± 5.0%) of CD31+ cells were also labeled, although most coexpressed CD34. Only 16% ± 22.3% of CD45-/CD31-/CD34- (triple-negative) cells were labeled with CS-ATM DM Green. After induction of cell death by either apoptosis or necrosis, >95% of ¹⁹F was released from the cells, indicating that fluorine retention can be used as a surrogate marker for cell survival. Labeled-SVF cells engrafted in a silicone breast phantom could be visualized with a clinical 3-Tesla magnetic resonance imaging scanner at a sensitivity of approximately 2 × 10⁶ cells at a depth of 5 mm. The current protocol can be used to image transplanted SVF cells at clinically relevant cell concentrations in patients.

SIGNIFICANCE

Stromal vascular fraction (SVF) cells harvested from adipose tissue offer great promise in regenerative medicine, but methods to track such cell therapies are needed to ensure correct administration and monitor survival. A clinical protocol was developed to harvest and label SVF cells with the fluorinated (¹⁹F) agent CS-1000, allowing cells to be tracked with (19)F magnetic resonance imaging (MRI). Flow cytometry evaluation revealed heterogeneous ¹⁹F uptake in SVF cells, confirming the need for careful characterization. The proposed protocol resulted in sufficient ¹⁹F uptake to allow imaging using a clinical MRI scanner with point-of-care processing.

Stromal vascular fraction: A regenerative reality? Part 2: Mechanisms of regenerative action

Adipose tissue is a rich source of cells with emerging promise for tissue engineering and regenerative medicine. The stromal vascular fraction (SVF), in particular, is an eclectic composite of cells with progenitor activity that includes preadipocytes, mesenchymal stem cells, pericytes, endothelial cells, and macrophages. SVF has enormous potential for therapeutic application and is being investigated for multiple clinical indications including lipotransfer, diabetes-related complications, nerve regeneration, burn wounds and numerous others. In Part 2 of our review, we explore the basic science behind the regenerative success of the SVF and discuss significant mechanisms that are at play. The existing literature suggests that angiogenesis, immunomodulation, differentiation, and extracellular matrix secretion are the main avenues through which regeneration and healing is achieved by the stromal vascular fraction.

Effect of platelet-rich plasma therapy associated with exercise training in musculoskeletal healing in rats

BACKGROUND

Muscle healing is a time-dependent process associated with an increase in the total amount of local collagen fibers. Platelet-rich plasma therapy (PRPT) associated with exercise may improve this healing process. The aim of this study was to demonstrate the regenerative effect of PRPT in association with exercise training on musculoskeletal healing.

METHODS

Male Wistar rats were submitted to an injury in the vastus lateralis muscle and randomly divided into 4 groups (n = 5/group): sedentary sham-operated (SSO); sedentary group submitted to PRPT (SPR); swim-trained (SWT); and swim-trained group submitted to PRPT (SWP). Serum lactate level was used to confirm the training protocol effectiveness to increase aerobic fitness. The collagen fiber concentration was measured by the polarization colors in picrosirius red-stained tissue sections.

RESULTS

Lactate levels decreased in both training groups (SWT and SWP; P < .05) after training (SWT: from 6.2 ± 0.44 to 4.7 ± 0.22 mmol/L; SWP: from 5.5 ± 0.99 to 4.0 ± 0.78 mmol/L). There were less type 1 collagen fibers in SWP group compared with other groups (SSO = 31.8 ± 10.3, SSP = 32.3 ± 13.5, SWT = 14.6 ± 13.4, SWP = 5.7 ± 4.7, P < .05), while there were more type 3 collagen fibers on SWP (SSO = 68.7 ± 9.8, SSP = 71.2 ± 12.2, SWT = 85.4 ± 13.4, SWP = 94.4 ± 4.6, P < .05) in the injured region.

CONCLUSION

Exercise in association with PRPT enhances the skeletal muscle-healing process.

Antiaging treatment of the facial skin by fat graft and adipose-derived stem cells

BACKGROUND

The regenerative property of fat grafting has been described. However, it is not clear whether the clinical results are attributable to the stem cells or are linked to other components of the adipose tissue. This work is aimed at analysis of the histologic and ultrastructural changes of aged facial skin after injection of fat graft in addition to its stromal vascular fraction, obtained by centrifugation, and to compare the results with those obtained by the injection of expanded adipose-derived mesenchymal stem cells.

METHODS

This study was performed in six consecutive patients who were candidates for face lift and whose ages ranged between 45 and 65 years. The patients underwent sampling of fat by liposuction from the abdominal region. The injection of fat and its stromal vascular fraction or expanded mesenchymal stem cells was performed in the preauricular areas. Fragments of skin were removed before and 3 months after each treatment and analyzed by optical and electron microscopy.

RESULTS

After treatment with the autologous lipidic component and stromal vascular fraction, the skin showed a decrease in elastic fiber network (elastosis) and the appearance of new oxytalan elastic fibers in papillary dermis. The ultrastructural examination showed a modified tridimensional architecture of the reticular dermis and the presence of a richer microvascular bed. Similar results following treatment with expanded mesenchymal stem cells were observed.

CONCLUSION

This study demonstrates that treatment with either fat and stromal vascular fraction or expanded mesenchymal stem cells modifies the pattern of the dermis, representing a skin rejuvenation effect.

The contribution of resident vascular stem cells to arterial pathology

Intimal accumulation of smooth muscle cells contributes to the development and progression of atherosclerotic lesions and restenosis following endovascular procedures. Arterial smooth muscle cells display heterogeneous phenotypes in both physiological and pathological conditions. In response to injury, dedifferentiated or synthetic smooth muscle cells proliferate and migrate from the tunica media into the intima. As a consequence, smooth muscle cells in vascular lesions show a prevalent dedifferentiated phenotype compared to the contractile appearance of normal media smooth muscle cells. The discovery of abundant stem antigen-expressing cells in vascular lesions also rarely detected in the tunica media of normal adult vessels stimulated a great scientific debate concerning the possibility that proliferating vascular wall-resident stem cells accumulate into the neointima and contribute to the progression of lesions. Although several experimental studies support this hypothesis, others researchers suggest a positive effect of stem cells on plaque stabilization. So, the real contribute of vascular wall-resident stem cells to pathological vascular remodelling needs further investigation. This review will examine the evidence and the contribution of vascular wall-resident stem cells to arterial pathobiology, in order to address future investigations as potential therapeutic target to prevent the progression of vascular diseases.

Cells and stimuli in small-caliber blood vessel tissue engineering

The absence of successful solutions in treatments of small-caliber vessel diseases led to the Vascular Tissue Engineering approach to develop functional nonimmunogenic tissue engineered blood vessels. In this context, the choice of cells to be seeded and the microenvironment conditioning are pivotal. Biochemical and biomechanical stimuli seem to activate physiological regulatory pathways that induce the production of molecules and proteins stimulating stem cell differentiation toward vascular lineage and reproducing natural cross-talks among vascular cells to improve the maturation of tissue engineered blood vessels. Thus, this review focuses on (1) available cell sources, and (2) biochemical and biomechanical stimuli, with the final aim to obtain the long-term stability of the endothelium and mechanical properties suitable for withstanding physiological load.

Gluteal and abdominal subcutaneous adipose tissue depots as stroma cell source: gluteal cells display increased adipogenic and osteogenic differentiation potentials

Human adipose-derived stroma cells (ADSCs) have successfully been employed in explorative therapeutic studies. Current evidence suggests that ADSCs are unevenly distributed in subcutaneous adipose tissue; therefore, the anatomical origin of ADSCs may influence clinical outcomes. This study was designed to investigate proliferation and differentiation capacities of ADSCs from the gluteal and abdominal depot of 8 females. All had normal BMI (22.01 ± 0.39 kg/m(2) ) and waist circumference (81.13 ± 2.33 cm). Examination by physicians and analysis of 31 laboratory parameters did not reveal possibly confounding medical disorders. Gluteal and abdominal adipose tissue was sampled by en bloc resection on day 7 (±1) after the last menses. Histological examination did not reveal significant depot-specific differences. As assessed by BrdU assay, proliferation of cells from both depots was similar after 24 h and analysis of 15 cell surface markers by flow cytometry identified the isolated cells as ADSCs, again without depot-specific differences. ADSCs from both depots differentiated poorly to chondroblasts. Gluteal ADSCs displayed significantly higher adipogenic differentiation potential than abdominal cells. Osteogenic differentiation was most pronounced in gluteal cells, whereas differentiation of abdominal ADSCs was severely impaired. Our data demonstrate a depot-specific difference in ADSC differentiation potential with abdominal cells failing to meet the criteria of multipotent ADSCs. This finding should be taken into account in future explorations of ADSC-derived therapeutic strategies.

Mesenchymal stem cells: potential for therapy and treatment of chronic non-healing skin wounds

Wound healing is a complex physiological process including overlapping phases (hemostatic/inflammatory, proliferating and remodeling phases). Every alteration in this mechanism might lead to pathological conditions of different medical relevance. Treatments for chronic non-healing wounds are expensive because reiterative treatments are needed. Regenerative medicine and in particular mesenchymal stem cells approach is emerging as new potential clinical application in wound healing. In the past decades, advance in the understanding of molecular mechanisms underlying wound healing process has led to extensive topical administration of growth factors as part of wound care. Currently, no definitive treatment is available and the research on optimal wound care depends upon the efficacy and cost-benefit of emerging therapies. Here we provide an overview on the novel approaches through stem cell therapy to improve cutaneous wound healing, with a focus on diabetic wounds and Systemic Sclerosis-associated ulcers, which are particularly challenging. Current and future treatment approaches are discussed with an emphasis on recent advances.

Adipose-derived stem cells: Implications in tissue regeneration

Adipose-derived stem cells (ASCs) are mesenchymal stem cells (MSCs) that are obtained from abundant adipose tissue, adherent on plastic culture flasks, can be expanded in vitro, and have the capacity to differentiate into multiple cell lineages. Unlike bone marrow-derived MSCs, ASCs can be obtained from abundant adipose tissue by a minimally invasive procedure, which results in a high number of cells. Therefore, ASCs are promising for regenerating tissues and organs damaged by injury and diseases. This article reviews the implications of ASCs in tissue regeneration.

Adult adipose-derived stem cells and breast cancer: a controversial relationship

Breast cancer is the most common cancer in women and autologous fat grafting is an important clinical application in treatment of post-surgical deformities. The simplicity of fat grafting procedures and the absence of subsequent visible scar prompted an increasing interest for this technique. The plasticity of adipose-derived stem cells (ASCs) obtained from stromal vascular fraction (SVF) of adult adipose tissue provided exciting perspectives for regenerative medicine and surgery. The recent discovery that SVF/ASC enrichment further ameliorates clinical efficacy of grafting ASCs suggest as ASC-mediated new adipogenesis and vasculogenesis. ASC adipogenic differentiation involves Akt activity and EGFRs, FGFRs, ERbB2 receptor-mediated pathways that also play a pivotal role in the regulation of breast cancer growth. Moreover, the finding that platelet-derived growth factors and hormones improved long-term maintenance of fat grafting raises new concerns for their use during breast reconstruction after cancer surgery. However, it remains unclear whether grafted or resident ASCs may increase the risk of de novo cancer development or recurrence. Preliminary follow-up studies seem to support the efficacy and safety of SVF/ASCs enrichment and the additional benefit from the combined use of autologous platelet-derived growth factors and hormones during breast reconstruction procedures. In the present review we highlighted the complex interplay between resident or grafted ASCs, mature adipocytes, dormant or active breast cancer cells and tumor microenvironment. Actually, data concerning the permissive role of ASCs on breast cancer progression are contrasting, although no clear evidence speaking against their use exists.

Increased survival of human free fat grafts with varying densities of human adipose-derived stem cells and platelet-rich plasma

The high absorption rate of transplanted fat has limited the application of autogenous fat grafts in the clinical setting. Therefore, this study aimed to evaluate the effects of platelet-rich plasma (PRP) and adipose-derived stem cells (ASCs) on fat regeneration by investigating the impact of PRP and conditioned medium on the biological characteristics of ASCs. Fat grafts were prepared with ASCs at densities of 10⁷ /ml, 10⁶ /ml, 10⁵ /ml, 10⁴ /ml and 0/ml with and without PRP and injected subcutaneously into nude mice. Liquid overflow method, haematoxylin and eosin staining, and immunohistochemical analyses were used to examine the fat grafts. The residual fat volume of the 10⁵ /ml ASC + PRP group was significantly higher than that of other treatment conditions after 90 days. Furthermore, histological examination revealed that in 10⁵ /ml ASCs-treated grafts normal adipocyte area and capillary formation were increased dramatically compared with other treatment conditions. It is concluded that fat grafts consisting of PRP and 10⁵ /ml ASCs constitute an ideal transplant strategy, which may result in decreased absorption and accelerated fat regeneration. This simple and reliable method could provide a valuable and needed tool in plastic and reconstructive surgery. Copyright © 2014 John Wiley & Sons, Ltd.

Human breast adipose‑derived stem cells: characterization and differentiation into mammary gland‑like epithelial cells promoted by autologous activated platelet‑rich plasma

Human adipose‑derived stem cells (ASCs) isolated from various body sites have been widely investigated in basic and clinical studies. However, ASCs derived from human breast tissue (hbASCs) have not been extensively investigated. In order to expand our understanding of hbASCs and examine their potential applications in stem cell research and cell‑based therapy, hbASCs were isolated from discarded surgical fat tissue following reduction mammoplasty and a comprehensive characterization of these hbASCs was performed, including analysis of their cellular morphology, growth features, cell surface protein markers and multilineage differentiation capacity. These hbASCs expressed cluster of differentiation (CD)44, CD49d, CD90 and CD105, but did not express CD31 and CD34. Subsequently, the hbASCs were differentiated into adipocytes, osteocytes and chondrocytes in vitro. In order to examine the potential applications of hbASCs in breast reconstruction, an approach to promote in vitro differentiation of hbASCs into mammary gland‑like epithelial cells (MGECs) was developed using activated autologous platelet‑rich plasma (PRP). A proliferation phase and a subsequent morphological conversion phase were observed during this differentiation process. PRP significantly promoted the growth of hbASCs in the proliferation phase and increased the eventual conversion rate of hbASCs into MGECs. Thus, to the best of our knowledge, the present study provided the first comprehensive characterization of hbASCs and validated their multipotency. Furthermore, it was revealed that activated autologous PRP was able to enhance the differentiation efficiency of hbASCs into MGECs. The present study and other studies of hbASCs may aid the development of improved breast reconstruction strategies.

The biomolecular basis of adipogenic differentiation of adipose-derived stem cells

There is considerable attention regarding the role of receptor signaling and downstream-regulated mediators in the homeostasis of adipocytes, but less information is available concerning adipose-derived stem cell (ASC) biology. Recent studies revealed that the pathways regulating ASC differentiation involve the activity of receptor tyrosine kinases (RTKs), including fibroblast growth factor, vascular endothelial growth factor, ErbB receptors and the downstream-regulated serine/threonine protein kinase B (Akt) and phosphatase and tensin homolog (PTEN) activity. RTKs are cell surface receptors that represent key regulators of cellular homeostasis but also play a critical role in the progression of cancer. Many of the metabolic effects and other consequences of activated RTKs are mediated by the modulation of Akt and extracellular signal-regulated protein kinases 1 (Erk-1) signaling. Akt activity sustains survival and the adipogenic differentiation of ASCs, whereas Erk-1 appears downregulated. The inhibition of FGFR-1, EGFR and ErbB2 reduced proliferation, but only FGFR-1 inihibition reduced Akt activity and adipogenesis. Adipogenesis and neovascularization are also chronologically and spatially coupled processes and RTK activation and downstream targets are also involved in ASC-mediated angiogenesis. The potentiality of ASCs and the possibility to modulate specific molecular pathways underlying ASC biological processes and, in particular, those shared with cancer cells, offer new exciting strategies in the field of regenerative medicine.

Age influence on stromal vascular fraction cell yield obtained from human lipoaspirates

BACKGROUND AIMS

The adipose stromal vascular fraction (SVF) is a heterogeneous population of mononuclear cells that includes approximately 1-10% mesenchymal stromal cells. These SVF cells can be freshly obtained from human lipo-aspirates and represent and ideal candidate for regenerative medicine applications. In the present study, we analyzed the SVF yield as a function of the patient's age.

METHODS

Adipose tissue samples from 52 informed subjects (all women) were processed by means of an innovative point-of-care technology for SVF isolation (GID platform). After enzymatic dissociation of adipose tissue and SVF pellet resuspension, we measured the concentration of mononucleated cells as well as other cell quality analyses on the cell suspension obtained. We then calculated the cell yield as total nucleated cells per milliliter of dry adipose processed.

RESULTS

The mean SVF yield obtained was 7.19 × 10(5) ± 2.11 × 10(5) total nucleated cells per milliliter of adipose tissue. Our results show that there is a clear statistically significant decline in SVF cell yield with increasing age.

CONCLUSIONS

Because all samples were obtained from the same donor area and the isolation technique used was the same in all cases, we conclude that the SVF cell yield in women is affected by patient age. Specific age-related factors should be analyzed in the future to explain these results.

Hypertensive rat lungs retain hallmarks of vascular disease upon decellularization but support the growth of mesenchymal stem cells

There are an insufficient number of donor organs available to meet the demand for lung transplantation. This issue could be addressed by regenerating functional tissue from diseased or damaged lungs that would otherwise be deemed unsuitable for transplant. Detergent-mediated whole-lung decellularization produces a three-dimensional natural scaffold that can be repopulated with various cell types. In this study, we investigated the decellularization and initial recellularization of diseased lungs using a rat model of monocrotaline-induced pulmonary hypertension (MCT-PHT). Decellularization of control and MCT-PHT Sprague-Dawley rat lungs was accomplished by treating the lungs with a combination of Triton X-100, sodium deoxycholate, NaCl, and DNase. The resulting acellular matrices were characterized by DNA quantification, Western blotting, immunohistochemistry, and proteomic analyses revealing that decellularization was able to remove cells while leaving the extracellular matrix (ECM) components and lung ultrastructure intact. Decellularization significantly reduced DNA content (∼30-fold in MCT-PHT lungs and ∼50-fold in the control lungs) and enriched ECM components (>60-fold in both the control and MCT-PHT lungs) while depleting cellular proteins. MicroCT visualization of MCT-PHT rat lungs indicated that the vasculature was narrowed as a result of MCT treatment, and this characteristic was unchanged by decellularization. Mean arterial vessel diameter of representative decellularized MCT-PHT and control scaffolds was estimated to be 0.152±0.134 mm and 0.247±0.160 mm, respectively. Decellularized MCT-PHT lung scaffolds supported attachment and survival of rat adipose-derived stem cells (rASCs), seeded into the airspace or the vasculature, for at least 2 weeks. The cells seeded in MCT-PHT lung scaffolds proliferated and underwent apoptosis similar to control scaffolds; however, the initial percentage of apoptotic cells was slightly higher in MCT-PHT lungs (2.79±2.03% vs. 1.05±1.02% of airway-seeded rASCs, and 4.47±1.21% vs. 2.66±0.10% of vascular seeded rASCs). The ECM of cell-seeded scaffolds showed no signs of degradation by the cells after 14 days in culture. These data suggest that diseased hypertensive lungs can be efficiently decellularized similar to control lungs and have the potential to be recellularized with mesenchymal stem cells with the ultimate goal of generating healthy, functional pulmonary tissue.

Stromal vascular fraction improves deep partial thickness burn wound healing

OBJECTIVE

The practice of early burn wound excision and wound closure by immediate autologous skin or skin substitutes is the preferred treatment in extensive deep partial and full-thickness burns. To date there is no proven definite medical treatment to decrease burn wound size and accelerate burn wound healing in modern clinical practice. Stromal vascular fraction is an autologous mixture that has multiple proven beneficial effects on different kinds of wounds. In our study, we investigated the effects of stromal vascular fraction on deep partial-thickness burn wound healing.

METHODS

In this study, 20 Wistar albino rats were used. Inguinal adipose tissue of the rats was surgically removed and stromal vascular fraction was isolated. Thereafter, deep second-degree burns were performed on the back of the rats by hot water. The rats were divided into two groups in a randomized fashion. The therapy group received stromal vascular fraction, whereas the control group received only physiologic serum by intradermal injection. Assessment of the burn wound healing between the groups was carried out by histopathologic and immuno-histochemical data.

RESULTS

Stromal vascular fraction increased vascular endothelial growth factor, proliferating cell nuclear antigen index, and reduced inflammation of the burn wound. Furthermore, vascularization and fibroblastic activity were achieved earlier and observed to be at higher levels in the stromal vascular fraction group.

CONCLUSIONS

Stromal vascular fraction improves burn wound healing by increasing cell proliferation and vascularization, reducing inflammation, and increasing fibroblastic activity.

"Strategic sequences" in adipose-derived stem cell nerve regeneration

BACKGROUND

Peripheral nerve injuries (PNI) are a major source of morbidity worldwide. The development of cellular regenerative therapies has the potential to improve outcomes of nerve injuries. However, an ideal therapy has yet to be found. The purpose of this study is to examine the current literature key points of regenerative techniques using human adipose-derived stem cells (hADSCs) for nerve regeneration and derive a comprehensive approach to hADSC therapy for PNI.

METHODS

A literature review was conducted using the electronic database PubMed to search for current experimental approaches to repairing PNI using hADSCs. Key search elements focused on specific components of nerve regeneration paradigms, including (1) support cells, (2) scaffolds, and (3) nerve conduits.

RESULTS

Strategic sequences were developed by optimizing the components of different experimental regenerative therapies. These sequences focus on priming hADSCs within a specialized growth medium, a hydrogel matrix base, and a collagen nerve conduit to achieve neuromodulatory nerve regeneration. hADSCs may exert their neuroregenerative influence through paracrine effects on surrounding Schwann cells in addition to physical interactions with injured tissue.

CONCLUSIONS

hADSCs may play a key role in nerve regeneration by acting primarily as support for local neurotrophic mediation and modulation of nerve growth rather than that of a primary neuronal differentiation agent.