Stromal vascular fraction improves deep partial thickness burn wound healing

The pathogenic role of the immune system in erectile dysfunction and Peyronie's disease: focusing on immunopathophysiology and potential therapeutic strategies

INTRODUCTION

Erectile dysfunction (ED) represents the major cause of male sexual dysfunction, which is often associated with obesity, diabetes mellitus, atherosclerotic cardiovascular disease, and cigarette smoking. Peyronie's disease is a chronic disorder associated with irreversible fibrotic damage of the tunica albuginea leading to ED, painful erection, coital disturbance, and physical and social complaints. Both conditions are characterized by chronic inflammation, oxidative stress, and significant changes in intracavernous hydrodynamics. In this scenario, oxidized lipoproteins, M1-polarized macrophages, proinflammatory cytokines (such as the tumor necrosis factor α), endothelial nitric oxide synthase, penile smooth muscle cells, and toll-like receptors represent the main triggers of the inflammatory process in ED. Phosphodiesterase-5 inhibitors are the most common treatment for ED. This treatment is used intermittently, as it is conceived as a symptomatic and not curative therapy. Moreover, not all patients respond to phosphodiesterase-5 inhibitors (35%-85%), particularly those with dysmetabolic phenotypes. Additional or alternative treatments are therefore desirable, mostly in refractory cases.

OBJECTIVES

In this review, we describe the immune-mediated pathogenesis of ED and Peyronie's disease (PD). In our literature search we placed particular emphasis on potentially practical therapeutic approaches, including natural products (such as polyphenols), due to their anti-inflammatory and antioxidant activities, stem cell therapy, and platelet-derived preparations.

METHODS

We searched PubMed/MEDLINE, Web of Science, Scopus, Cochrane Library, Google Scholar, and institutional websites. Original studies, narrative reviews, systematic reviews, and meta-analyses written in English were searched, screened, and selected.

RESULTS

In animal models of ED and PD, therapeutic approaches, including anti-inflammatory and antioxidant agents, stem cell therapy, and platelet-derived preparations, have provided positive results, including improved penile function, reduced inflammation and oxidative stress, and promotion of tissue repair. However, clinical evidence of improvement in human patients is still insufficient.

CONCLUSION

Promising results for treating ED and PD have been shown in preclinical and pilot clinical studies, but specific clinical trials are needed to validate the efficacy of these therapeutic approaches in men with ED.

Efficacy of the immediate adipose-derived stromal vascular fraction autograft on functional sensorimotor recovery after spinal cord contusion in rats

BACKGROUND

Spinal cord injuries (SCI) lead to functional alteration with important consequences such as motor and sensory disorders. The repair strategies developed to date remain ineffective. The adipose tissue-derived stromal vascular fraction (SVF) is composed of a cocktail of cells with trophic, pro-angiogenic and immunomodulatory effects. Numerous therapeutic benefits were shown for tissue reconstitution, peripheral neuropathy and for the improvement of neurodegenerative diseases. Here, the therapeutic efficacy of SVF on sensorimotor recovery after an acute thoracic spinal cord contusion in adult rats was determined.

METHOD

Male Sprague Dawley rats (n = 45) were divided into 3 groups: SHAM (without SCI and treatment), NaCl (animals with a spinal lesion and receiving a saline injection through the dura mater) and SVF (animals with a spinal lesion and receiving a fraction of fat removed from adipocytes through the dura mater). Some animals were sacrificed 14 days after the start of the experiment to determine the inflammatory reaction by measuring the interleukin-1β, interleukin-6 and Tumor Necrosis Factor-α in the lesion area. Other animals were followed once a week for 12 weeks to assess functional recovery (postural and locomotor activities, sensorimotor coordination). At the end of this period, spinal reflexivity (rate-dependent depression of the H-reflex) and physiological adjustments (ventilatory response to metabosensitive muscle activation following muscle fatigue) were measured with electrophysiological tools.

RESULTS

Compared to non-treated animals, results indicated that the SVF reduced the endogenous inflammation and increased the behavioral recovery in treated animals. Moreover, H-reflex depression and ventilatory adjustments to muscle fatigue were found to be comparable between SHAM and SVF groups.

CONCLUSION

Our results highlight the effectiveness of SVF and its high therapeutic potential to improve sensorimotor functions and to restore the segmental sensorimotor loop and the communication between supra- and sub-lesional spinal cord regions after traumatic contusion.

Use of adipose derived stem cells accelerates the healing process in third-degree burns

INTRODUCTION

Burns are defined as a traumatic injury, usually of thermal origin, that affects the epithelial and adjacent tissue and is classified according to the depth reached. Tissue repair involved in this type of injury is often a challenge both due to its severity and the multiplicity of complications. Regenerative medicine has focused on the use of low-level laser photobiomodulation therapy (LLLT) and adipose-derived stem cells (ADSC), especially in the early stages of the process, to promote better healing and shorten repair time. Therefore, aim of this study was to evaluate the action of LLLT (660 nm) and ADSC in the repair process of burned skin tissue and investigate the association of the techniques (LLLT and ADSC).

MATERIALS AND METHODS

An in vivo study was carried out using 96 rats (Wister) with a scald burn model at a temperature of 95ºC, exposing the animal's back for 14 s. Animals were randomized into seven groups and three periods, five, 14 and 21 days. The groups included GC: Control group, ADSC-: Group treated with CD49d negative cells, ADSC+ : Group treated with positive CD49d cells, CULT: Group treated with conventional isolation cells, LLLT: Group treated only with LLLT Low Power Laser, ADSC-LLLT: Group treated with CD49d negative cells and LLLT. ADSC+LLLT: Group treated with positive CD49d cells and LLLT. The groups treated with LLLT (660 nm; 5 J/cm2) received irradiation three times a week, on alternate days for five, 14 and 21 days, according to the time of biopsy. ADSC-treated groups received one to three applications of the cells in a total volume of 1000 μL starting soon after the surgical debridement of the burn. Photographic monitoring was carried out at 5, 14 and 21 days after the beginning of the experiment to assess the degree of lesion contraction. Macroscopic, morphometric and histopathological analyzes were performed.

RESULTS

We showed significant re-epithelialization as well as an improvement in the healing process in the ADSC+, LLLT and ADSC+LLLT groups. We observed effects in the reduction of the inflammatory phase, increase in angiogenesis, decrease in oedema, greater collagen deposition, and better organization of the extracellular matrix compared to the other treatments. Moreover, the immunomagnetic separation of ADSC cells through the expression of the CD49d protein proved to be a useful means to obtain a more homogeneous population of cells with a role in tissue regeneration compared to the ADSC- and CULT groups.

CONCLUSION

In conclusion, the association of ADSC+ with LLLT was effective in accelerating the burn repair process, stimulating cell proliferation and formation of more normal skin tissue.

Use of autologous adipose tissue in acute burn wound management: A systematic review

Fat transfer is increasingly used as part of our reconstructive armamentarium to address the challenges encountered in burn wounds and reconstructive surgery. The present systematic review aimed to evaluate the effectiveness of autologous fat transfer for acute burn wound management. A systematic review of the US National Library of Medicine, Cochrane Library, Web of Science, and Embase was conducted on October 15, 2022 (registration number CDR42022369726). A database watch was performed until submission of the manuscript. The review focused on wound healing. All studies reporting fat transfer in adult patients (at least 5 patients reported) with deep 2nd degree burn wounds were included. The database search yielded a total of 720 records and 367 patients were included from 3 studies. A statistically significant improvement in scar texture, scar appearance, and time to healing was reported in one study in the fat transfer group versus control (P<0.001). Similarly, scores for scar color, scar thickness, scar stiffness, and scar regularity increased significantly. The small number of included studies and their heterogeneity did not allow a meta-regression to be performed. This systematic review emphasizes the limited evidence currently available regarding the use of autologous fat transfer to improve burn wound healing in adult patients, even though it seems promising. Future search should focus on randomized controlled trials with a larger number of participants.

Evaluating the quality of studies reporting on clinical applications of stromal vascular fraction: A systematic review and proposed reporting guidelines (CLINIC-STRA-SVF)

Background

The stromal vascular fraction (SVF) has been widely explored in a number of therapeutic applications in several specialties. Its therapeutic potential is being increasingly demonstrated, although its mechanism of action is still unclear.

Objective

To evaluate the quality of studies reporting on clinical applications of SVF.

Method

This is a systematic literature review that followed the PRISMA guidelines with the search of the studies from December 1, 2012, to December 1, 2022, in the following databases: MEDLINE, LILACS and EMBASE. The level of evidence of the studies was assessed using the GRADE system, and the rigor used in the publication of the results was assessed in relation to adherence to the guidelines indicated by the EQUATOR Network Group. The CLINIC - STRA-SVF reporting guideline was developed after the completion of this systematic review.

Results

A total of 538 articles were found, and 77 articles were selected after reading the titles and abstracts and removing duplicates. Then, 15 studies were removed for not meeting the inclusion criteria, leaving 62 studies. The CLINIC - STRA-SVF was developed and consists of 33 items and two tables.

Conclusion

There is scientific evidence, although mostly with a low level of evidence, that the use of SVF in clinical applications is safe and effective. The information published in these studies should be standardized, and the CLINIC - STRA-SVF reporting guideline proposed in this study may assist in the design, conduct, recording and reporting of clinical trials and others clinical studies involving the SVF.

Application of Adipose-Tissue Derived Products for Burn Wound Healing

Burn injuries are a significant global health concern, leading to high morbidity and mortality. Deep burn injuries often result in delayed healing and scar formation, necessitating effective treatment options. Regenerative medicine, particularly cell therapy using adipose-derived stem cells (ASCs), has emerged as a promising approach to improving burn wound healing and reducing scarring. Both in vitro and preclinical studies have demonstrated the efficacy of ASCs and the stromal vascular fraction (SVF) in addressing burn wounds. The application of ASCs for burn healing has been studied in various forms, including autologous or allogeneic cells delivered in suspension or within scaffolds in animal burn models. Additionally, ASC-derived non-cellular components, such as conditioned media or exosomes have shown promise. Injection of ASCs and SVF at burn sites have been demonstrated to enhance wound healing by reducing inflammation and promoting angiogenesis, epithelialization, and granulation tissue formation through their paracrine secretome. This review discusses the applications of adipose tissue derivatives in burn injury treatment, encompassing ASC transplantation, as well as the utilization of non-cellular components utilization for therapeutic benefits. The application of ASCs in burn healing in the future will require addressing donor variability, safety, and efficacy for successful clinical application.

Efficacy of stromal vascular fraction and enzyme-free mechanical isolation therapy in experimental full thickness burn wounds

BACKGROUND

Autologous cell suspensions obtained by a stromal vascular fraction (SVF) and enzyme-free mechanical isolation (EMI) are an alternative in the treatment of burn wounds. In this study, we aimed to investigate the effect of autologous cell suspensions obtained by SVF and EMI on full-thickness skin burn wounds.

METHODS

A total of 45 male Sprague-Dawley rats were divided into three groups, SVF group, EMI group, and SVF + EMI group. The groups were also classified as the first, second, and third week of the burn to reveal the effect of the treatment on the burn in the early, middle, and late stages. For treatment, 0.2 ml SVF or 0.2 ml EMI was injected subcutaneously into the burn lesions of the subjects. Histopathological examination was performed on the burn wounds taken at the end of the experiment, and Ki67, CD44, CD73, CD90, and CK17 expressions were evaluated.

RESULTS

Histological examination revealed that there was no improvement in the control samples, but the skin was multicellular, vascularization was present. Histologic scores in all groups was significantly better than control, and SVF + EMI was the best group in terms of recovery (p < 0.05). Ki67, CK17, CD44, CD73, and CD90 expressions were significantly higher in the treatment groups compared to the control (p < 0.05).

CONCLUSION

We found in our study that both applications significantly increased the healing of the burn wound. Moreover, SVF + EMI application provided more improvement than SVF or EMI alone.

Adipose-derived stem cells applied in skin diseases, wound healing and skin defects: a review

Adipose tissue presents a comparably easy source for obtaining stem cells, and more studies are increasingly investigating the therapeutic potential of adipose-derived stem cells. Wound healing, especially in chronic wounds, and treatment of skin diseases are some of the fields investigated. In this narrative review, the authors give an overview of some of the latest studies concerning wound healing as well as treatment of several skin diseases and concentrate on the different forms of application of adipose-derived stem cells.

The effect of stromal vascular fraction in an experimental frostbite injury model

BACKGROUND

Despite current treatment modalities, frostbite remains an injury with a poor prognosis which may cause functional morbidities. Several experimental and clinical studies have demonstrated that stromal vascular fraction is an autologous mixture, which can improve wound healing and vasculogenesis. The aim of this study was to show the beneficial effects of stromal vascular fraction on experimental frostbite healing.

MATERIAL AND METHODS

Stromal vascular fraction (SVF) was harvested from 5 rats after excision of the inguinal fat pads. Another 20 rats were separated into 2 groups of 10 as the SVF group and the control group. A frostbite injury was created on each rat using a cryoprobe frozen with liquid nitrogen (-196 °C). SVF was applied to the SVF group and phosphate-buffered saline to the control group. All injections were performed subcutaneously within the frostbite injury area. Biopsies were performed on days 5 and 14 for histopathological and immunochemical evaluations. The tissue perfusion rates of both groups were assessed on day 14 using indocyanine green angiography (SPY system).

RESULTS

The increase in mean tissue perfusion was 373.3% ( ± 32.1) in the SVF group and 123.8% ( ± 16.3) in the control group (p < 0.001). The macroscopic wound reduction rates of the SVF and control groups were 25.5% ( ± 19.1) and 18.0% ( ± 5.9), respectively on day 5%, and 78.2% ( ± 9.2) and 57.3% ( ± 16.7) on day 14 (p = 0.007; p = 0.003). Acute inflammation and the fibrosis gradient were significantly decreased in the SVF group compared to the control group (p = 0.004, p = 0.054 respectively on day 14). Granulation tissue amount, re-epithelialization score and neovascularization were significantly increased in the SVF group (p = 0.006, p = 0.010 and p = 0.021, respectively on day 14).

CONCLUSIONS

The study results demonstrated that SVF increases frostbite wound healing by increasing tissue perfusion rate, neovascularization and re-epithelialization, and modulating acute inflammation and fibrosis.

Fat Juice: A Novel Approach on the Usage and Preparation of Adipose Tissue By-Products

BACKGROUND

Adipose tissue is considered to be naturally rich in a range of bioactive substances that may be extracted directly for therapeutic use without the need for cell isolation or culture.

OBJECTIVES

The aim of this study was to introduce a novel approach that utilizes stromal vascular fraction in conjunction with fat extract, termed "fat juice," and to perform a comprehensive biochemical analysis in relation to the potential clinical relevance of this new combination.

METHODS

A total of 11 samples of fat juice from the abdominal lipoaspirate were extracted from 11 healthy patients and analyzed in terms of the quantity and viability of stem cells, the presence and quantification of connective tissue fibers on histopathologic examination, and the levels of interleukin-6, mannose receptor C type 1, and vascular endothelial growth factor measured by enzyme-linked immunosorbent assay.

RESULTS

Total stem cell amounts ranged from 0.14 × 105 to 1.31 × 105, and cell viability rates varied between 20% and 67.9%. Interleukin-6 protein and vascular endothelial growth factor expressions were highest in Sample 3, while staining intensity was highest in Sample 4. For collagen I, collagen III, and elastin, the highest expressions were observed in Samples 4 and 8, in Sample 3, and in Samples 2 and 4, respectively.

CONCLUSIONS

Fat juice provides an easy-to-inject concentration of adipocyte/preadipocytes, red blood cells, adipose-derived stem cells, endothelial-derived cells, and cell residues. Prepared through an easy isolation process enabling abundant availability, fat juice seems to be an effective skin quality enhancer with potential for widespread use in the fields of plastic surgery, dermatology, and aesthetic/regenerative medicine.

Fluidic Device System for Mechanical Processing and Filtering of Human Lipoaspirate Enhances Recovery of Mesenchymal Stem Cells

BACKGROUND

Adipose tissue is an easily accessible source of stem and progenitor cells that offers exciting promise as an injectable autologous therapeutic for regenerative applications. Mechanical processing is preferred over enzymatic digestion, and the most common method involves shuffling lipoaspirate between syringes and filtering to produce nanofat. Although nanofat has shown exciting clinical results, the authors hypothesized that new device designs could enhance recovery of stem/progenitor cells through optimization of fluid dynamics principles, integration, and automation.

METHODS

The authors designed and fabricated the emulsification and micronization device (EMD) and the filtration device (FD) to replace the manual nanofat procedures. Using human lipoaspirate samples, the EMD and the FD were optimized and compared to traditional nanofat using ex vivo measurements of cell number, viability, and percentage of mesenchymal stem cells and endothelial progenitor cells.

RESULTS

The EMD produced results statistically similar to nanofat, and these findings were confirmed for a cohort of diabetic patients. Combining the FD with the EMD was superior to manually filtered nanofat in terms of both recovered cell percentages (>1.5-fold) and numbers (two- to three-fold). Differences were statistically significant for total mesenchymal stem cells and a DPP4 + /CD55 + subpopulation linked to improved wound healing in diabetes.

CONCLUSIONS

The new EMD and the FD improved mechanical processing of human lipoaspirate in terms of mesenchymal stem cell enrichment and number compared to traditional nanofat. Future work will seek to investigate the wound healing response both in vitro and in vivo, and to refine the technology for automated operation within clinical settings.

CLINICAL RELEVANCE STATEMENT

The new devices improved mechanical processing of human lipoaspirate in terms of stem cell enrichment and number compared to traditional methods. Future work will seek to validate wound healing response and refine the technology for automated operation within clinical settings.

Intraoperative Intradermal Application of Stromal Vascular Fraction into the Abdominal Suture Line: Histological Analysis of Abdominal Scar Tissue

BACKGROUND

Stem cell therapy is a promising new approach to wound healing. Stromal vascular fraction is a heterogeneous collection of cells, including adipose-derived stem cells, which are traditionally isolated using a manual collagenase-based technique. To our knowledge, this is the first human study that histologically assesses the potential of intraoperative intradermal injection of stromal vascular fraction on skin regeneration.

METHODS

In this controlled study, 20 patients undergoing deep inferior epigastric perforator flap breast reconstruction and bilateral flank liposuction were included. Stromal vascular fraction was injected intradermally into one side of the abdominal suture line, while the other side served as a control. Outcome measures included analysis of stromal vascular fraction by flow cytometry, histological analysis of scar tissue, and scar photography.

RESULTS

Cell yield for application and cell viability were 55.9 ± 28.5 × 10⁶ and 75.1% ± 14.5%, respectively. Age and body mass index were positively correlated with the number of cells for application and adipose-derived stem cells. Mean vascular density, elastic fiber content, collagen maturity (scar index), epidermal thickness, and number of rete ridges all showed higher values on the treated side. Furthermore, the injected number of adipose-derived stem cells and pericytes positively correlated with vascular density.

CONCLUSIONS

It is safe to speculate that intradermal stromal vascular fraction injection at the beginning of the healing process increases vascular density, collagen maturity and organization, elastic fiber content, epidermal thickness, epidermal-dermal anchoring of the scarring skin and is therefore responsible for improved skin regeneration. It is a viable and safe method that can be used as an adjunctive treatment in plastic surgery procedures where suboptimal wound healing is anticipated.

LEVEL OF EVIDENCE IV

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 .

Stromal Vascular Fraction for Knee Osteoarthritis - An Update

Orthobiologics never cease to cause popularity within the medical science field, distinctly in regenerative medicine. Recently, adipose tissue has been an object of interest for many researchers and medical experts due to the fact that it represents a novel and potential cell source for tissue engineering and regenerative medicine purposes. Stromal vascular fraction (SVF), for instance, which is an adipose tissue-derivative, has generated optimistic results in many scenarios. Its biological potential can be harnessed and administered into injured tissues, particularly areas in which standard healing is disrupted. This is a typical feature of osteoarthritis (OA), a common degenerative joint disease which is outlined by persistent inflammation and destruction of surrounding tissues. SVF is known to carry a large amount of stem and progenitor cells, which are able to perform self-renewal, differentiation, and proliferation. Furthermore, they also secrete several cytokines and several growth factors, effectively sustaining immune modulatory effects and halting the escalated pro-inflammatory status of OA. Although SVF has shown interesting results throughout the medical community, additional research is still highly desirable in order to further elucidate its potential regarding musculoskeletal disorders, especially OA.

Adipose stromal vascular fraction: a promising treatment for severe burn injury

Thermal skin burn injury affects both adults and children globally. Severe burn injury affects a patient's life psychologically, cosmetically, and socially. The pathophysiology of burn injury is well known. Due to the complexity of burn pathophysiology, the development of specific treatment aiding in tissue regeneration is required. Treatment of burn injury depends on burn severity, size of the burn and availability of donor site. Burn healing requires biochemical and cellular events to ensure better cell response to biochemical signals of the healing process. This led to the consideration of using cell therapy for severe burn injury. Adult mesenchymal stem cells have become a therapeutic option because of their ability for self-renewal and differentiation. Adipose stromal vascular fraction (SVF), isolated from adipose tissues, is a heterogeneous cell population that contains adipose-derived stromal/stem cells (ADSC), stromal, endothelial, hematopoietic and pericytic lineages. SVF isolation has advantages over other types of cells; such as heterogeneity of cells, lower invasive extraction procedure, high yield of cells, and fast and easy isolation. Therefore, SVF has many characteristics that enable them to be a therapeutic option for burn treatment. Studies have been conducted mostly in animal models to investigate their therapeutic potential for burn injury. They can be used alone or in combination with other treatment options. Treatment with both ADSCs and/or SVF enhances burn healing through increasing re-epithelization, angiogenesis and decreasing inflammation and scar formation. Research needs to be conducted for a better understanding of the SVF mechanism in burn healing and to optimize current techniques for enhanced treatment outcomes.

Clinical applications of adipose-derived stromal vascular fraction in veterinary practice

Adipose tissue-derived stromal vascular fraction (AdSVF) comprises a heterogeneous cell population, including the multipotent mesenchymal stem cells, hematopoietic stem cells, immune cells, endothelial cells, fibroblasts, and pericytes. As such, multipotent adipose tissue-derived mesenchymal stem cells (AdMSCs), are one of the important components of AdSVF. Commonly used techniques to harvest AdSVF involve enzymatic or non-enzymatic methods. The enzymatic method is considered to be the gold standard technique due to its higher yield. The cellular components of AdSVF can be resuspended in normal saline, platelet-rich plasma, or phosphate-buffered saline to produce a ready-to-use solution. Freshly isolated AdSVF has exhibited promising osteogenic and vasculogenic capacity. AdSVF has already been proven to possess therapeutic potential for osteoarthritis management. It is also an attractive therapeutic option for enhancing wound healing. In addition, the combined use of AdSVF and platelet-rich plasma has an additive stimulatory effect in accelerating wound healing and can be considered an alternative to AdMSC treatment. It is also widely used for managing various orthopaedic conditions in clinical settings and has the potential for regenerating bone, cartilage, and tendons. Autologous AdSVF cells are used along with bone substitutes and other biological factors as an alternative to conventional bone grafting techniques owing to their promising osteogenic and vasculogenic capacity. It can also be used for treating osteonecrosis, meniscus tear, chondromalacia, and tendon injuries in veterinary practice. It has several advantages over in vitro expanded AdMSC, including precluding the need for culturing, reduced risk of cell contamination, and cost-effectiveness, making it ideal for clinical use.

Preparation, biocompatibility, and wound healing effects of O-carboxymethyl chitosan nonwoven fabrics in partial-thickness burn model

This study was aimed at preparing O-carboxymethyl chitosan (CM-CTS) fabrics, and examining the wound healing effects on partial-thickness burn. The functional polysaccharides were produced from chitosan needle-punched nonwovens reacted with chloroacetic acid. Then the biocompatibility and biological functions were evaluated through fibroblast L-929 and SD rats. CM-CTS fabrics were obtained with elongation at break more than 42%, tensile strength reaching 0.65 N/mm², and water vapor transmission rate about 2600 g/m²∙24 h. Moreover, CM-CTS fabrics could effectively promote the mouse L-929 migration in vitro. CM-CTS fabrics yielded satisfactory results in angiogenesis, collagen deposition, interleukin-6 content, transforming growth factor level and healing rate, which were superior to the positive control and model groups after rats suffering with partial-thickness burn. In conclusion, CM-CTS fabrics possessed proper mechanical properties, air permeability, favorable biocompatibility, acceleration on fibroblasts migration and healing capacity for partial-thickness burn injury, and owned good potential as high-quality wound dressing.

Burn Wound Healing: Clinical Complications, Medical Care, Treatment, and Dressing Types: The Current State of Knowledge for Clinical Practice

According to the World Health Organization (WHO), it is estimated that each year approximately 11 million people suffer from burn wounds, 180,000 of whom die because of such injuries. Regardless of the factors causing burns, these are complicated wounds that are difficult to heal and are associated with high mortality rates. Medical care of a burn patient requires a lot of commitment, experience, and multidirectional management, including surgical activities and widely understood pharmacological approaches. This paper aims to comprehensively review the current literature concerning burn wounds, including classification of burns, complications, medical care, and pharmacological treatment. We also overviewed the dressings (with an emphasis on the newest innovations in this field) that are currently used in medical practice to heal wounds.

Analysis of the Curative Effect and Influencing Factors of Collagen Sponge Combined with Autologous Skin Graft in the Treatment of Deep Burn Patients

Burn is one of the common traumatic diseases in clinics. After deep burn, the complicated changes of the condition are caused by the burn wound, which ends with the repair of the wound. For patients with deep burns, whether the wound can be repaired as soon as possible is the key to the success of clinical treatment. For patients with deep burns, due to the lack of an autologous skin source, scar hyperplasia at donor site, skin graft repair at donor site, postoperative flap necrosis, and other problems in traditional surgical procedures, the method of improving function only by an autologous skin source has been unable to perform the later function reconstruction in patients with deep burns. In this study, collagen sponge combined with autologous skin graft was used to treat patients with deep burn, and the clinical efficacy of the patients was observed, and the related factors affecting the efficacy of the patients were analyzed. The results showed that collagen sponge combined with autologous skin graft was effective in the treatment of deep burn patients, and it was worth popularizing. Deep III-IV degree burns, wound infection, and hospital stay >3 months are all risk factors affecting the postoperative curative effect of patients. Therefore, in the clinical work, we should focus on patients with deep III-IV degree burns, perform surgery as soon as possible, and actively deal with wounds to prevent infection, which is beneficial to improve the curative effect.

Translational products of adipose tissue-derived mesenchymal stem cells: Bench to bedside applications

With developments in the field of tissue engineering and regenerative medicine, the use of biological products for the treatment of various disorders has come into the limelight among researchers and clinicians. Among all the available biological tissues, research and exploration of adipose tissue have become more robust. Adipose tissue engineering aims to develop by-products and their substitutes for their regenerative and immunomodulatory potential. The use of biodegradable scaffolds along with adipose tissue products has a major role in cellular growth, proliferation, and differentiation. Adipose tissue, apart from being the powerhouse of energy storage, also functions as the largest endocrine organ, with the release of various adipokines. The progenitor cells among the heterogeneous population in the adipose tissue are of paramount importance as they determine the capacity of regeneration of these tissues. The results of adipose-derived stem-cell assisted fat grafting to provide numerous growth factors and adipokines that improve vasculogenesis, fat graft integration, and survival within the recipient tissue and promote the regeneration of tissue are promising. Adipose tissue gives rise to various by-products upon processing. This article highlights the significance and the usage of various adipose tissue by-products, their individual characteristics, and their clinical applications.

Therapeutic approach of adipose-derived mesenchymal stem cells in refractory peptic ulcer

Peptic ulcer is one of the most common gastrointestinal tract disorders worldwide, associated with challenges such as refractory morbidity, bleeding, interference with use of anticoagulants, and potential side effects associated with long-term use of proton pump inhibitors. A peptic ulcer is a defect in gastric or duodenal mucosa extending from muscularis mucosa to deeper layers of the stomach wall. In most cases, ulcers respond to standard treatments. However, in some people, peptic ulcer becomes resistant to conventional treatment or recurs after initially successful therapy. Therefore, new and safe treatments, including the use of stem cells, are highly favored for these patients. Adipose-derived mesenchymal stem cells are readily available in large quantities with minimal invasive intervention, and isolation of adipose-derived mesenchymal stromal stem cells (ASC) produces large amounts of stem cells, which are essential for cell-based and restorative therapies. These cells have high flexibility and can differentiate into several types of cells in vitro. This article will investigate the effects and possible mechanisms and signaling pathways of adipose tissue-derived mesenchymal stem cells in patients with refractory peptic ulcers.

Technological Advances of 3D Scaffold-Based Stem Cell/Exosome Therapy in Tissues and Organs

Recently, biomaterial scaffolds have been widely applied in the field of tissue engineering and regenerative medicine. Due to different production methods, unique types of three-dimensional (3D) scaffolds can be fabricated to meet the structural characteristics of tissues and organs, and provide suitable 3D microenvironments. The therapeutic effects of stem cell (SC) therapy in tissues and organs are considerable and have attracted the attention of academic researchers worldwide. However, due to the limitations and challenges of SC therapy, exosome therapy can be used for basic research and clinical translation. The review briefly introduces the materials (nature or polymer), shapes (hydrogels, particles and porous solids) and fabrication methods (crosslinking or bioprinting) of 3D scaffolds, and describes the recent progress in SC/exosome therapy with 3D scaffolds over the past 5 years (2016-2020). Normal SC/exosome therapy can improve the structure and function of diseased and damaged tissues and organs. In addition, 3D scaffold-based SC/exosome therapy can significantly improve the structure and function cardiac and neural tissues for the treatment of various refractory diseases. Besides, exosome therapy has the same therapeutic effects as SC therapy but without the disadvantages. Hence, 3D scaffold therapy provides an alternative strategy for treatment of refractory and incurable diseases and has entered a transformation period from basic research into clinical translation as a viable therapeutic option in the future.

A Feasibility Study on 3D Bioprinting of Microfat Constructs Towards Wound Healing Applications

Chronic wounds affect over 400,000 people in the United States alone, with up to 60,000 deaths each year from non-healing ulcerations. Tissue grafting (e.g., autografts, allografts, and xenografts) and synthetic skin substitutes are common treatment methods, but most solutions are limited to symptomatic treatment and do not address the underlying causes of the chronic wound. Use of fat grafts for wound healing applications has demonstrated promise but these grafts suffer from low cell viability and poor retention at the wound site resulting in suboptimal healing of chronic wounds. Herein, we report on an innovative closed-loop fat processing system (MiniTC^TM) that can efficiently process lipoaspirates into microfat clusters comprising of highly viable regenerative cell population (i.e., adipose stromal cells, endothelial progenitors) preserved in their native niche. Cryopreservation of MiniTC^TM isolated microfat retained cell count and viability. To improve microfat retention and engraftment at the wound site, microfat was mixed with methacrylated collagen (CMA) bioink and 3D printed to generate microfat-laden collagen constructs. Modulating the concentration of microfat in CMA constructs had no effect on print fidelity or stability of the printed constructs. Results from the Alamar blue assay showed that the cells remain viable and metabolically active in microfat-laden collagen constructs for up to 10 days in vitro. Further, quantitative assessment of cell culture medium over time using ELISA revealed a temporal expression of proinflammatory and anti-inflammatory cytokines indicative of wound healing microenvironment progression. Together, these results demonstrate that 3D bioprinting of microfat-laden collagen constructs is a promising approach to generate viable microfat grafts for potential use in treatment of non-healing chronic wounds.

Combination of platelet rich plasma and stromal vascular fraction on the level of vascular endothelial growth factor in rat subjects experiencing deep dermal burn injury

Background

The healing process of burns includes coagulation, inflammation, and remodeling. Vascular endothelial growth factor (VEGF) is involved throughout this healing process. Stem cells from the platelet-rich plasma (PRP) with stromal vascular fraction (SVF) can increase concentrations of growth factors, including VEGF. This is expected to accelerate burn healing. The aim of this study was to determine the effect of a combination of PRP and SVF on VEGF levels in a rats model of deep dermal burn wound healing.

Materials and methods

This is an experimental research study in rats using a post-test control group design with 4 groups: A) control, B) Vaseline, C) topical PRP and SVF, and D) PRP and SVF injection. Burn wounds were induced according to the modified Guo method.

Results

In a rats model of deep dermal wound healing, topical Vaseline significantly increased serum VEGF compared to control. Topical application and injection of stem cells also significantly increased serum VEGF compared to control and Vaseline. The VEGF concentration was significantly higher following injection of PRP and SVF, suggesting that the injection route is more effective at increasing VEGF levels compared to the topical application of stem cells.

Conclusion

The combination of PRP and SVF, either by injection or topical application, can increase VEGF levels during the healing process from deep dermal burns.

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Stem cells can increase concentrations of growth factors.

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Topical application and injection of stem cells significantly increased serum VEGF compared to control.

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The VEGF concentration was significantly higher following injection of PRP and SVFs.

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The injection route of stem cells is more effective at increasing VEGF levels compared to the topical application.

An update on stem cells applications in burn wound healing

Burn wounds have proven to be capable of having a long lasting devastating effects on human body. Conventional therapeutic approaches are not up to the mark as they are unable to completely heal the burn wound easily and effectively. Major pitfalls of these treatments include hypertrophic scarring, contracture and necrosis. Presence of these limitations in the current therapies necessitate the search for a better and more efficient cure. Regenerative potency of stem cells in burn wound healing outweigh the traditional treatment procedures. The use of multiple kinds of stem cells are gaining interest due to their enhanced healing efficiency. Distinctions of stem cells include better and faster burn wound healing, decreased inflammation levels, less scar progression and fibrosis on site. In this review, we have discussed the wound-healing process, present methods used for stem cells administration, methods of enhancing stem cells potency and human studies. Pre-clinical and the clinical studies focused on the treatment of thermal and radiation burns using stem cells from 2003 till the present time have been enlisted. Studies shows that the use of stem cells on burn wounds, whether alone or by the help of a scaffold significantly improves healing. Homing of the stem cells at the wound site results in the re-epithelialization, angiogenesis, granulation, inhibition of apoptosis, and regeneration of skin appendages together with reduced infection rate in the human studies. Several studies on animals have shown that stem cells can effectively promote wound healing. Although more research is needed to find out the effectiveness of this treatment in patients with severe burn wounds.

Cannula Size Effect on Stromal Vascular Fraction Content of Fat Grafts

Background

Fat is an active and dynamic tissue composed of adipocytes supported by a structural framework known as the stromal vascular fraction (SVF). SVF is traditionally isolated by enzymatic processing, but new methods are being investigated to isolate it mechanically. Recent studies propose that fat harvested with larger cannulas has a higher survival rate, most likely due to a higher concentration of SVF.

Methods

Lipoaspirates were obtained from 10 patients who underwent elective liposuction using a 5-mm and a 1-mm cannula attached to a syringe using standard pressure. The fat was aspirated from the same area at adjacent sites. An estimated 5-mm fat particles were also cut down to 1-mm using a micronizer (Marina Medical). A 5-cm³ volume of each sample was compressed through a 0.5-mm opening strainer and rinsed with normal saline to extrude the oil. The resultant SVF left on the strainer was then measured in a 1-cm³ syringe.

Results

The volume extracted from a 5-mm cannula (mean, 0.23 cm³; SD, 0.10) versus a 1-mm cannula (mean, 0.11 cm³; SD, 0.06) was statistically significant (P = 0.009). An H&E-stained slide from the SVF was obtained for confirmation. Finally, 5-mm fat particles cut down to 1-mm particles using the micronizer resulted in an average volume of 0.20 cm³, which was higher than the average volume harvested with a 1-mm cannula.

Conclusions

Harvesting with a 5-mm cannula resulted in significantly more SVF than harvesting with a 1-mm cannula. Resizing fat particles harvested with a larger cannula down to 1-mm resulted in higher SVF than SVF obtained with a 1-mm cannula directly.

Update on the role of emerging stem cell technology in head and neck medicine

Head and neck surgery is a broad discipline that involves the management of complex conditions such as burns, skin cancer, head and neck cancer, congenital abnormalities, and facial rejuvenation. For patients with cancer, surgery, radiotherapy, and chemotherapy are often the main modes of treatment. Many patients require follow-up reconstructive surgery, and the use of stem cells offers novel treatments that could aid recovery. Laryngeal, tracheal, and neuronal tissues are frequently damaged by surgery in the head and neck and these tissues have little intrinsic regenerative ability. Pluripotent embryonic stem cells retain the ability to differentiate into a wide variety of cells meaning that large tissue defects can be reduced by stimulating new cell growth. Research has demonstrated potential benefits of using stem cells in facial rejuvenation procedures and the management of burns sequelae. The advancements made in the use of adult progenitor stem cells as a possible source for pluripotent stem cells (induced pluripotent stem cells) mean that ethical considerations around the use of embryological tissue can be minimized, allowing for more research to take place. Currently, the evidence base for the use of stem cells in head and neck surgery is limited, but it has now been proven that stem cells can act as a source for lost or damaged tissue in the head and neck. With continuous advancements being made in the fields of tissue engineering, it is likely that stem cells will play a major role in head and neck surgery in the future.

[Research progress of adipose-derived stem cells in skin scar prevention and treatment]

Objective

To review the research progress of adipose-derived stem cells (ADSCs) in skin scar prevention and treatment.

Methods

The related literature was extensively reviewed and analyzed. The recent in vitroand in vivo experiments and clinical studies on the role of ADSCs in skin scar prevention and treatment, and the possible mechanisms and biomaterials to optimize the effect of ADSCs were summarized.

Results

As demonstrated by in vitro and in vivo experiments and clinical studies, ADSCs participate in the whole process of skin wound healing and may prevent and treat skin scars by reducing inflammation, promoting angiogenesis, or inhibiting (muscle) fibroblasts activity to reduce collagen deposition through the p38/mitogen-activated protein kinase, peroxisome proliferator activated receptor γ, transforming growth factor β ₁/Smads pathways. Moreover, bioengineered materials such as hydrogel from acellular porcine adipose tissue, porcine small-intestine submucosa, and poly (3-hydroxybutyrate-co-hydroxyvalerate) scaffold may further enhance the efficacy of ADSCs in preventing and treating skin scars.

Conclusion

Remarkable progress has been made in the application of ADSCs in skin scar prevention and treatment. While, further studies are still needed to explore the application methods of ADSCs in the clinic.

Therapeutic Targeting of Neutrophil Extracellular Traps Improves Primary and Secondary Intention Wound Healing in Mice

Background

Neutrophils are the first responders in wound healing after injury that mediate pro- and anti-inflammatory activities i.a. through the formation of extracellular traps (NETs). However, excessive NETs presence in wound tissue can cause local hyperinflammation and -coagulation resulting in delayed wound healing. To improve wound healing, we aimed to examine the role of NETs and DNase1 on primary and secondary wound healing.

Methods

The study included 93 C57BL/6 mice, with 3 different genotypes: wildtype, Pad4-, and DNase1-Knockout (KO). Pad4-KO mice show limited NETs formation, while DNase1-KO mice cannot disintegrate them. All 3 genotypes were included in (1) a laparotomy group and (2) a thermal injury group. Animals in both groups either received DNase1 or a vehicle i.p. post wound induction and wound assessment and euthanasia were conducted. Laparotomy and burn scars were assessed using the stony brook scar evaluation scale and modified Yeong scale respectively. Tissue was analyzed histologically using H&E staining. Ly6g, Collagen I and III, SMA, and Fibrinogen were visualized and neutrophils activation (NE, MPO) and NETs (H3cit) formation assessed.

Results

All animals survived with no complications. DNase1 treatment led to a significantly improved scar appearance in both groups, which was also seen in Pad4-KO mice. In the laparotomy group DNase1 improved collagen deposition and fibrin concentration was significantly reduced by DNase1 treatment. Markers of neutrophil activation were significantly reduced in the treatment and Pad4-KO group. In the thermal injury group wound closure time was significantly reduced after DNase1 treatment and in the Pad4-KO group. Even though inflammation remained high in the thermal injury model over time, neutrophil activation and NETs formation were significantly reduced by DNase1 treatment compared to controls.

Discussion

Primary and secondary intention wound healing is improved by targeting NETs through DNase1 treatment or genetic KO, as assessed by wound closure time and scar appearances. Additionally, wound stability was not affected by DNASE treatment. The results suggest that overall wound healing is accelerated and DNase1 appears to be a promising option to reduce scar formation; which should be evaluated in humans.

Feasibility of First Injection of Autologous Adipose Tissue-Derived Stromal Vascular Fraction in Human Scarred Vocal Folds: A Nonrandomized Controlled Trial

Importance

Patients with scarred vocal folds, whether congenitally or after phonosurgery, often exhibit dysphonia that negatively affects daily life and is difficult to treat. The autologous adipose tissue-derived stromal vascular fraction (ADSVF) is a readily accessible source of cells with angiogenic, anti-inflammatory, immunomodulatory, and regenerative properties.

Objective

To evaluate the feasibility and tolerability of local injections of autologous ADSVF in patients with scarred vocal folds.

Design, Setting, and Participants

CELLCORDES (Innovative Treatment for Scarred Vocal Cords by Local Injection of Autologous Stromal Vascular Fraction) is a prospective, open-label, single-arm, single-center, nonrandomized controlled trial with a 12-month follow-up and patient enrollment from April 1, 2016, to June 30, 2017. Eight patients with severe dysphonia attributable to vocal fold scarring associated with a congenital malformation or resulting from microsurgical sequelae (voice handicap index score >60 of 120) completed the study. Data analysis was performed from September 1, 2018, to January 1, 2019.

Interventions

Injection of ADSVF into 1 or 2 vocal folds.

Main Outcomes and Measures

The primary outcomes were feasibility and the number and severity of adverse events associated with ADSVF-based therapy. The secondary outcomes were changes in vocal assessment, videolaryngostroboscopy, self-evaluation of dysphonia, and quality of life at 1, 6, and 12 months after cell therapy.

Results

Seven women and 1 man (mean [SD] age, 44.6 [10.4] years) were enrolled in this study. Adverse events associated with liposuction and ADSVF injection occurred; most of them resolved spontaneously. One patient received minor treatment to drain local bruising, and another experienced a minor contour defect at the liposuction site. At 12 months, the voice handicap index score was improved in all patients, with a mean (SD) improvement from baseline of 40.1 (21.5) points. Seven patients (88%) were considered to be responders, defined as improvement by 18 points or more in the voice handicap index score (the minimum clinically important difference).

Conclusions and Relevance

The findings suggest that autologous ADSVF injection in scarred vocal folds is feasible and tolerable. The findings require confirmation in a randomized clinical trial with a larger population.

Trial Registration

ClinicalTrials.gov Identifier: NCT02622464.

Umbilical cord-derived mesenchymal stem cells preconditioned with isorhamnetin: potential therapy for burn wounds

BACKGROUND

Impaired wound healing can be associated with different pathological states. Burn wounds are the most common and detrimental injuries and remain a major health issue worldwide. Mesenchymal stem cells (MSCs) possess the ability to regenerate tissues by secreting factors involved in promoting cell migration, proliferation and differentiation, while suppressing immune reactions. Preconditioning of MSCs with small molecules having cytoprotective properties can enhance the potential of these cells for their use in cell-based therapeutics.

AIM

To enhance the therapeutic potential of MSCs by preconditioning them with isorhamnetin for second degree burn wounds in rats.

METHODS

Human umbilical cord MSCs (hU-MSCs) were isolated and characterized by surface markers, CD105, vimentin and CD90. For preconditioning, hU-MSCs were treated with isorhamnetin after selection of the optimized concentration (5 µmol/L) by cytotoxicity analysis. The migration potential of these MSCs was analyzed by the in vitro scratch assay. The healing potential of normal, and preconditioned hU-MSCs was compared by transplanting these MSCs in a rat model of a second degree burn wound. Normal, and preconditioned MSCs (IH + MSCs) were transplanted after 72 h of burn injury and observed for 2 wk. Histological and gene expression analyses were performed on day 7 and 14 after cell transplantation to determine complete wound healing.

RESULTS

The scratch assay analysis showed a significant reduction in the scratch area in the case of IH + MSCs compared to the normal untreated MSCs at 24 h, while complete closure of the scratch area was observed at 48 h. Histological analysis showed reduced inflammation, completely remodeled epidermis and dermis without scar formation and regeneration of hair follicles in the group that received IH + MSCs. Gene expression analysis was time dependent and more pronounced in the case of IH + MSCs. Interleukin (IL)-1β, IL-6 and Bcl-2 associated X genes showed significant downregulation, while transforming growth factor β, vascular endothelial growth factor, Bcl-2 and matrix metallopeptidase 9 showed significant upregulation compared to the burn wound, showing increased angiogenesis and reduced inflammation and apoptosis.

CONCLUSION

Preconditioning of hU-MSCs with isorhamnetin decreases wound progression by reducing inflammation, and improving tissue architecture and wound healing. The study outcome is expected to lead to an improved cell-based therapeutic approach for burn wounds.

Use of ovine acellular peritoneal matrix combined with honey and ovine fetal skin extract in the healing of full-thickness infected burn wounds in a rat model

Treatment of infected burn wounds remains a challenge in burn units. Silver-sulfadiazine (SSD) is the most commonly used topical antimicrobial agent in managing these wounds. We aimed to accelerate the healing of burn wounds by combined application of ovine acellular peritoneal matrix (OAPM), honey (H), and ovine fetal skin extract (OFSE). Sixty-four standardized burn wounds were created on the dorsum of 16 rats and were subsequently inoculated with Staphyloccocus aureus and Pseudomonas aeruginosa. After 48 hr, the wounds were surgically debrided and received either physiologic saline (control group) or SSD, OAPM+SSD, OAPM+H+SSD, and OAPM+H+OFSE+SSD. The healing wounds were evaluated for size, bacterial counts, histopathology, and biomechanical properties on days 3, 7, 14, 21, and 28 after surgery. All treatments had effectively reduced the level of S. aureus and P. aeruginosa on wounds compared to the control group by day 3 and 7. The wounds treated with combined application of OAPM+H+OFSE+SSD demonstrated considerable inflammation reduction, fibroplasia, complete re-epithelialization, and wound contraction together with significantly lesser scar tissue formation. Treatment with OAPM+H+OFSE+SSD showed superior biomechanical properties of the healing wounds. The findings suggested that the synergistic effect of dressing the wounds with OAPM, H, and OFSE was a very effective approach in accelerating the healing process of the experimentally induced infected full-thickness burn wounds in rats.

[Current review of factors in the stem cell donor that influence the regenerative potential of adipose tissue-derived stem cells]

BACKGROUND

Regenerative therapies like cell-assisted lipotransfer or preclinical experimental studies use adipose tissue-derived stem cells (ASCs) as the main therapeutic agent. But there are also factors depending on the clinical donor that influence the cell yield and regenerative potential of human ASCs and stromal vascular fraction (SVF). Therefore, the aim of this review was to identify and evaluate these factors according to current literature.

METHODS

For this purpose, a systematic literature review was performed with focus on factors affecting the regenerative potential of ASCs and SVF using the National Library of Medicine.

RESULTS

Currently, there is an abundance of studies regarding clinical donor factors influencing ASCs properties. But there is some contradiction and need for further investigation. Nevertheless, we identified several recurrent factors: age, sex, weight, diabetes, lipoedema, use of antidepressants, anti-hormonal therapy and chemotherapy.

CONCLUSION

We recommend characterisation of the ASC donor cohort in all publications, regardless of whether they are experimental studies or clinical trials. By these means, donor factors that influence experimental or clinical findings can be made transparent and results are more comparable. Moreover, this knowledge can be used for study design to form a homogenous donor cohort by precise clinical history and physical examination.

Mechanical Vibration-Extracted Stromal Vascular Fraction Improves Volume Retention after Autologous Fat Grafting

BACKGROUND

The stromal vascular fraction can improve volume retention after fat grafting, but the optimal stromal vascular fraction extraction method remains controversial. This study investigated the effect of mechanical vibration on stromal vascular fraction activity and explored the efficacy of vibration as a new extraction method compared to centrifugation, enzyme digestion, and nanoemulsion methods.

METHODS

Twenty-four rabbits were divided into three groups, and adipose tissue was harvested from the scapular region of each rabbit. In the first group, stromal vascular fraction was extracted from adipose tissue by vibration with different frequencies and durations. Cell counts and colony formation were assessed to determine the optimal vibration parameters. In the second group, stromal vascular fraction was extracted by the four methods, and the cell counts, proliferation, and adipogenic capabilities were observed in vitro. In the third group, adipose tissue mixed with stromal vascular fraction extracted by means of the four methods was grafted into rabbit ears. Volume retention and histologic changes were evaluated over 24 weeks.

RESULTS

Stromal vascular fraction activity was not influenced by low-frequency (≤45 Hz) and short-duration (≤20 minutes) vibrations. Vibration at 30 Hz for 15 minutes was most efficient for stromal vascular fraction extraction. In vitro, stromal vascular fraction extracted by vibration showed advantages for cell viability. In vivo, the vibration group showed a more normal tissue morphology and a higher retention rate (60.68 ± 7.07 percent) than the enzyme digestion (31.88 ± 4.99 percent), centrifugation (43.76 ± 4.32 percent), and nanoemulsion groups (21.79 ± 3.57 percent) (p < 0.05).

CONCLUSION

Vibration at 30 Hz for 15 minutes is recommended as a novel nonenzymatic method to extract stromal vascular fraction with high activity.

Systematic Review of Stem-Cell-Based Therapy of Burn Wounds: Lessons Learned from Animal and Clinical Studies

Treatment of severe burn wounds presents a daunting medical challenge, and novel approaches promoting healing and reducing scarring are highly desirable. The application of mesenchymal stem/stromal cells (MSCs) has been suggested as a novel treatment. In this paper, we present systematic reviews of pre-clinical and clinical studies of MSC therapy for second- or third-degree thermal burn wounds. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, the PubMed and Embase databases were searched, and interventional studies of MSC therapy using rodent models (21 studies) or human burn patients (three studies) were included in the pre-clinical and clinical reviews, respectively, where both overall outcome and wound-healing-phase-specific methodologies and effects were assessed. The pre-clinical studies demonstrated a promising effect of the application of MSCs on several wound healing phases. The clinical studies also suggested that the MSC treatment was beneficial, particularly in the remodeling phase. However, the limited number of studies, their lack of homogeneity in study design, relatively high risk of bias, lack of reporting on mode of action (MOA), and discontinuity of evidence restrict the strength of these findings. This comprehensive review presents an overview of available methodologies to assess the MOA of MSC treatment for distinct wound healing phases. Furthermore, it includes a set of recommendations for the design of high-quality clinical studies that can determine the efficacy of MSCs as a therapy for burn wounds.

Therapeutic application of adipose-derived stromal vascular fraction in diabetic foot

Diabetic foot is one of the severest complications of diabetes. In severe cases, this disease may be lead to amputation or even death due to secondary infection and ischemic necrosis. Since the ineffectiveness of traditional therapy, autologous stem cell transplantation has been used to treat diabetic foot. This simple, safe, and effective therapy is expected to be applied and promoted in the future.In this review, we described the detailed pathogenesis of diabetic foot and the common clinical treatments currently used. We also revealed vascular remodeling as the potential mechanism of therapeutic functions of adipose-derived stromal vascular fraction (SVF) in treating diabetic foot.

Umbilical Cord-Derived Mesenchymal Stem Cell-Derived Exosomes Combined Pluronic F127 Hydrogel Promote Chronic Diabetic Wound Healing and Complete Skin Regeneration

Purpose

Chronic refractory wounds are a multifactorial comorbidity of diabetes mellitus with the characteristic of impaired vascular networks. Currently, there is a lack of effective treatments for such wounds. Various types of mesenchymal stem cell-derived exosomes (MSC-exos) have been shown to exert multiple therapeutic effects on skin regeneration. We aimed to determine whether a constructed combination of human umbilical cord MSC (hUCMSC)-derived exosomes (hUCMSC-exos) and Pluronic F-127 (PF-127) hydrogel could improve wound healing.

Materials and Methods

We topically applied human umbilical cord-derived MSC (hUCMSC)-derived exosomes (hUCMSC-exos) encapsulated in a thermosensitive PF-127 hydrogel to a full-thickness cutaneous wound in a streptozotocin-induced diabetic rat model. The material properties and wound healing ability of the hydrogel and cellular responses were analyzed.

Results

Compared with hUCMSC-exos, PF-127-only or control treatment, the combination of PF-127 and hUCMSC-exos resulted in a significantly accelerated wound closure rate, increased expression of CD31 and Ki67, enhanced regeneration of granulation tissue and upregulated expression of vascular endothelial growth factor (VEGF) and factor transforming growth factor beta-1 (TGFβ-1).

Conclusion

The efficient delivery of hUCMSC-exos in PF-127 gel and improved exosome ability could promote diabetic wound healing. Thus, this biomaterial-based exosome therapy may represent a new therapeutic approach for cutaneous regeneration of chronic wounds.

A Concise Review on Tissue Engineered Artificial Skin Grafts for Chronic Wound Treatment: Can We Reconstruct Functional Skin Tissue In Vitro?

Chronic wounds occur as a consequence of a prolonged inflammatory phase during the healing process, which precludes skin regeneration. Typical treatment for chronic wounds includes application of autografts, allografts collected from cadaver, and topical delivery of antioxidant, anti-inflammatory, and antibacterial agents. Nevertheless, the mentioned therapies are not sufficient for extensive or deep wounds. Moreover, application of allogeneic skin grafts carries high risk of rejection and treatment failure. Advanced therapies for chronic wounds involve application of bioengineered artificial skin substitutes to overcome graft rejection as well as topical delivery of mesenchymal stem cells to reduce inflammation and accelerate the healing process. This review focuses on the concept of skin tissue engineering, which is a modern approach to chronic wound treatment. The aim of the article is to summarize common therapies for chronic wounds and recent achievements in the development of bioengineered artificial skin constructs, including analysis of biomaterials and cells widely used for skin graft production. This review also presents attempts to reconstruct nerves, pigmentation, and skin appendages (hair follicles, sweat glands) using artificial skin grafts as well as recent trends in the engineering of biomaterials, aiming to produce nanocomposite skin substitutes (nanofilled polymer composites) with controlled antibacterial activity. Finally, the article describes the composition, advantages, and limitations of both newly developed and commercially available bioengineered skin substitutes.

Efficacy of topical platelet-rich plasma and chitosan co-administration on Candida albicans-infected partial thickness burn wound healing

This study aims to evaluate the effects of topical sole and co-administration of Platelet-rich plasma (PRP) and chitosan on the infected burn wounds model by Candida albicans in Wistar rats. A circle partial thickness contact burn wound model occurred via brass a size of 8mm diameter between the shoulders and after that, 50μl of a suspension containing C. albicans yeast (5×10⁷) colony forming unit was poured on the surface of the wound. The experimental groups included Control, Clotrimazole, PRP and Chitosan+PRP that received any agent, Clotrimazole®, PRP and Chitosan+PRP to treat the wound, respectively. To assess the healing rate, wound size rate, tissue yeast count (TYC) and immunohistochemical staining for heat shock protein 70 (HSP70), HSP 90 and proliferating cell nuclear antigen (PCNA) were conducted. Moreover, enzymatic activity of glutathione peroxidase (GPx), superoxide dismutase (SOD) and malondialdehyde (MDA) rate were evaluated. The results demonstrated that the co-administration of Chitosan+PRP drastically (P<0.05) decreased the wound size and TYC rate comparing to other groups (P<0.05). Immunohistochemical results for HSP 70, HSP 90 and PCNA showed positive reactions and increased intensity in all the treated groups comparing to the control group. Activities of GPx and SOD were higher and the level of MDA was lower all treated groups compared to the control group. A topical use of PRP and chitosan can be advantageous in the infected burn wounds healing.

Fractionation of Adipose Tissue Procedure With a Disposable One-Hole Fractionator

BACKGROUND

Adipose tissue has been widely used in regenerative surgery for its therapeutic potential. This potential is often ascribed to the stromal vascular fraction (SVF), which can be mechanically isolated. Mechanical isolation results in an SVF that retains intact cell-cell communication including extracellular matrix and is therefore named tissue-SVF (tSVF).

OBJECTIVES

The aim of this study was to evaluate a new disposable 1-hole fractionator for fractionation of adipose tissue (FAT), and compare this new device with the existing reusable 3-hole fractionator.

METHODS

The composition of tSVF obtained via the 1-hole fractionator was histologically and histochemically compared to unprocessed adipose tissue. The number of viable nuclear cells in tSVF obtained by the 1-hole and 3-hole fractionators as well as unprocessed adipose tissue were compared after enzymatic isolation and tested for colony-forming capacity. Flow cytometry was used to compare different cell compositions based on surface marker expression between tSVF isolated by the two types of fractionators.

RESULTS

Fractionation of adipose tissue with the 1-hole fractionator condenses vasculature and extracellular matrix by disrupting adipocytes. The number of viable nuclear cells in tSVF obtained with the two fractionators was comparable and significantly higher than unprocessed lipoaspirate. Furthermore, tSVF isolated by both fractionators showed similar cell compositions and comparable colony-forming capacities.

CONCLUSIONS

FAT with a disposable 1-hole fractionator effectively isolates tSVF with a cell count and cell composition comparable to the fraction obtained with the 3-hole reusable fractionator. The disposable 1-hole fractionator, however, is safer and more user friendly.

Adipose-derived stromal vascular fraction aids epithelialisation and angiogenesis in an animal model

OBJECTIVE

Limited data exist regarding the correlation between adipose-derived stromal vascular fraction (SVF) and wound healing. The aim of this study was to investigate the direct effect of intradermally injected SVF on full-thickness cutaneous wounds in a murine model.

METHOD

Wistar rats were divided into three groups (A, B and C) according to their day of euthanasia (day 7, 16 and 21). Inguinal fat pad was excised and SVF enzymatically extracted. Full-thickness cutaneous wounds were created on each side of the dorsum; SVF injected intradermally at one side while the contralateral wound served as control receiving normal saline. Postoperatively, evaluation of wound healing was performed by planimetry (percentages of wound contraction, epithelialisation and total wound healing) on days 0, 3, 5, 7, 10, 13, 16 and 21, and histology and immunochemistry (cellular infiltration score, collagen production score, neoangiogenesis and epithelial thickness) on days 7, 16 and 21.

RESULTS

Despite the high rate of wound contraction, it was significantly lower in the SVF-treated wounds on day 21 (p=0.037). On days 13, 16 and 21, the percentages of epithelialisation were higher in the SVF-treated wounds compared with control wounds (p=0.026, p=0.048 and p=0.05, respectively). Histologically, the number of new vessels was significantly higher in the SVF-treated wounds compared with controls on days seven (p=0.028) and 16 (p=0.027). This was also confirmed by immunohistochemistry. No significant differences were found between treated and control wounds regarding cellular infiltration score, collagen production score and epithelial thickness.

CONCLUSION

Data indicate that intradermally injected SVF increases angiogenesis and enhances epithelialisation in full-thickness cutaneous wounds in rats.

Hypoxia Rapidly Induces the Expression of Cardiomyogenic Factors in Human Adipose-Derived Adherent Stromal Cells

BACKGROUND

The efficacy of interstitial vascular fraction (SVF) transplantation in the treatment of heart disease has been proven in a variety of in vivo studies. In a previous study, we found that bone marrow-derived mesenchymal stem cells (BM-MSCs) altered their expression of several cardiomyogenic factors under hypoxic conditions.

METHODS

We hypothesized that hypoxia may also induce obtained adipose-derived adherent stromal cells (ADASs) from SVFs and adipose-derived stem cells (ASCs) to differentiate into cardiomyocytes and/or cells with comparable phenotypes. We examined the differentiation markers of cell lineages in ADASs and ASCs according to time by hypoxic stress and found that only ADASs expressed cardiomyogenic markers within 24 h under hypoxic conditions in association with the expression of hypoxia-inducible factor 1-α (HIF-1α).

RESULTS

Differentially secreted proteins in a conditioned medium (CM) from ASCs and ADASs under normoxic or hypoxic conditions were detected using an antibody assay and may be associated with a dramatic increase in the expression of cardiomyogenic markers in only ADASs. Furthermore, the cardiomyogenic factors were expressed more rapidly in ADASs than in ASCs under hypoxic conditions in association with the expression of HIF-1α, and angiogenin, fibroblast growth factor-19 (FGF-19) and/or macrophage inhibitory factor (MIF) are related.

CONCLUSIONS

These results provide new insights into the applicability of ADASs preconditioned by hypoxic stress in cardiac diseases.

Wound healing and fibrosis: current stem cell therapies

Scarring is a result of the wound healing response and causes tissue dysfunction after injury. This process is readily evident in the skin, but also occurs internally across organ systems in the form of fibrosis. Stem cells are crucial to the innate tissue healing response and, as such, present a possible modality to therapeutically promote regenerative healing while minimizing scaring. In this review, the cellular basis of scaring and fibrosis is examined. Current stem cell therapies under exploration for skin wound healing and internal organ fibrosis are discussed. While most therapeutic approaches rely on the direct application of progenitor-type cells to injured tissue to promote healing, novel strategies to manipulate the scarring response are also presented. As our understanding of developmental and stem cell biology continues to increase, therapies to encourage regeneration of healthy functional tissue after damage secondary to injury or disease will continue to expand.