Autologous Adipose Tissue Graft to Treat Hypertensive Leg Ulcer: A Pilot Study

The Efficacy of Stem Cells in Wound Healing: A Systematic Review

Wound healing is an intricate process involving coordinated interactions among inflammatory cells, skin fibroblasts, keratinocytes, and endothelial cells. Successful tissue repair hinges on controlled inflammation, angiogenesis, and remodeling facilitated by the exchange of cytokines and growth factors. Comorbid conditions can disrupt this process, leading to significant morbidity and mortality. Stem cell therapy has emerged as a promising strategy for enhancing wound healing, utilizing cells from diverse sources such as endothelial progenitor cells, bone marrow, adipose tissue, dermal, and inducible pluripotent stem cells. In this systematic review, we comprehensively investigated stem cell therapies in chronic wounds, summarizing the clinical, translational, and primary literature. A systematic search across PubMed, Embase, Web of Science, Google Scholar, and Cochrane Library yielded 22,454 articles, reduced to 44 studies after rigorous screening. Notably, adipose tissue-derived mesenchymal stem cells (AD-MSCs) emerged as an optimal choice due to their abundant supply, easy isolation, ex vivo proliferative capacities, and pro-angiogenic factor secretion. AD-MSCs have shown efficacy in various conditions, including peripheral arterial disease, diabetic wounds, hypertensive ulcers, bullous diabeticorum, venous ulcers, and post-Mohs micrographic surgery wounds. Delivery methods varied, encompassing topical application, scaffold incorporation, combination with plasma-rich proteins, and atelocollagen administration. Integration with local wound care practices resulted in reduced pain, shorter healing times, and improved cosmesis. Stem cell transplantation represents a potential therapeutic avenue, as transplanted stem cells not only differentiate into diverse skin cell types but also release essential cytokines and growth factors, fostering increased angiogenesis. This approach holds promise for intractable wounds, particularly chronic lower-leg wounds, and as a post-Mohs micrographic surgery intervention for healing defects through secondary intention. The potential reduction in healthcare costs and enhancement of patient quality of life further underscore the attractiveness of stem cell applications in wound care. This systematic review explores the clinical utilization of stem cells and stem cell products, providing valuable insights into their role as ancillary methods in treating chronic wounds.

New Paradigm in Diabetic Foot Ulcer Grafting Techniques Using 3D-Bioprinted Autologous Minimally Manipulated Homologous Adipose Tissue (3D-AMHAT) with Fibrin Gel Acting as a Biodegradable Scaffold

Adipose tissue is an abundant source of extracellular substances that support the tissue repair process. This pilot study was carried out to determine the efficacy of 3D-bioprinted autologous adipose tissue grafts on diabetic foot ulcers (DFUs), with fibrin gel used to stabilise the graft. This was a single-arm pilot study in a tertiary hospital that provides diabetic wound care services. A total of 10 patients with a DFU were enrolled, and the primary endpoint was complete healing within 12 weeks. The secondary endpoints were wound size reduction, time to healing, and adverse events. Seven out of ten patients showed complete healing of their DFU within 12 weeks (at 2, 4, 5, 10, and 12 weeks, respectively). The wound size reduction rate was significantly and progressively reduced over time. According to our data, autologous adipose tissue grafting using a 3D bioprinter, with the addition of fibrin gel that acts as a scaffold, promotes wound healing with high-quality skin reconstruction. Throughout this study period, no adverse events were observed.

Convergence of Biofabrication Technologies and Cell Therapies for Wound Healing

BACKGROUND

Cell therapy holds great promise for cutaneous wound treatment but presents practical and clinical challenges, mainly related to the lack of a supportive and inductive microenvironment for cells after transplantation. Main: This review delineates the challenges and opportunities in cell therapies for acute and chronic wounds and highlights the contribution of biofabricated matrices to skin reconstruction. The complexity of the wound healing process necessitates the development of matrices with properties comparable to the extracellular matrix in the skin for their structure and composition. Over recent years, emerging biofabrication technologies have shown a capacity for creating complex matrices. In cell therapy, multifunctional material-based matrices have benefits in enhancing cell retention and survival, reducing healing time, and preventing infection and cell transplant rejection. Additionally, they can improve the efficacy of cell therapy, owing to their potential to modulate cell behaviors and regulate spatiotemporal patterns of wound healing.

CONCLUSION

The ongoing development of biofabrication technologies promises to deliver material-based matrices that are rich in supportive, phenotype patterning cell niches and are robust enough to provide physical protection for the cells during implantation.

Tissue Stromal Vascular Fraction Improves Early Scar Healing: A Prospective Randomized Multicenter Clinical Trial

BACKGROUND

Wound healing and scar formation depends on a plethora of factors. Given the impact of abnormal scar formation, interventions aimed to improve scar formation would be most advantageous. The tissue stromal vascular fraction (tSVF) of adipose tissue is composed of a heterogenous mixture of cells embedded in extracellular matrix. It contains growth factors and cytokines involved in wound-healing processes, eg, parenchymal proliferation, inflammation, angiogenesis, and matrix remodeling.

OBJECTIVES

The aim of this study was to investigate the hypothesis that tSVF reduces postsurgical scar formation.

METHODS

This prospective, double-blind, placebo-controlled, randomized trial was conducted between 2016 and 2020. Forty mammoplasty patients were enrolled and followed for 1 year. At the end of the mammoplasty procedure, all patients received tSVF in the lateral 5 cm of the horizontal scar of 1 breast and a placebo injection in the contralateral breast to serve as an intrapatient control. Primary outcome was scar quality measure by the Patient and Observer Scar Assessment Scale (POSAS). Secondary outcomes were obtained from photographic evaluation and histologic analysis of scar tissue samples.

RESULTS

Thirty-four of 40 patients completed follow-up. At 6 months postoperation, injection of tSVF had significantly improved postoperative scar appearance as assessed by the POSAS questionnaire. No difference was observed at 12 months postoperation. No improvement was seen based on the evaluation of photographs and histologic analysis of postoperative scars between both groups.

CONCLUSIONS

Injection of tSVF resulted in improved wound healing and reduced scar formation at 6 months postoperation, without any noticeable advantageous effects seen at 12 months.

LEVEL OF EVIDENCE: 2

A Peptide/MicroRNA-31 nanomedicine within an electrospun biomaterial designed to regenerate wounds in vivo

microRNA-31 (miR-31) has been identified to be downregulated in pathologies associated with delayed wound repair. Thus, it was proposed that the delivery of a plasmid encoding miR-31 (pmiR-31) to the skin could hold potential in promoting wound healing. Effective delivery of pmiR-31 was potentiated by encapsulation with the CHAT peptide to form nanocomplexes, this improved cellular entry and elicited a potent increase in miR-31 expression in vitro in both skin human keratinocyte cell line (HaCaT) and human microvascular endothelial cell line (HMEC-1). Transfection efficiencies with CHAT/pEFGP-N1 were significant at 15.2 ± 8.1% in HMEC-1 cells and >40% in HaCaT cells. In this study, the CHAT/pmiR-31 nanocomplexes at a N:P ratio of 10 had an average particle size of 74.2 nm with a cationic zeta potential of 9.7 mV. Delivery of CHAT/pmiR-31 to HaCaT and HMEC-1 cells resulted in significant improvements in cell migration capacity and increased angiogenesis. In vivo studies were conducted in C57BL/6 J mice were CHAT/pmiR-31 was delivered via electrospun PVA nanofibres, demonstrating a significant increase in epidermal (increase of ∼38.2 µm) and stratum corneum (increase of 8.2 µm) layers compared to controls. Furthermore, treatment in vivo with CHAT/pmiR-31 increased angiogenesis in wounds compared to controls, with a significant increase in vessel diameter by ∼20.4 µm compared against a commercial dressing control (Durafiber™). Together, these data demonstrate that the delivery of CHAT/pmiR-31 nanocomplexes from electrospun PVA nanofibres represent an innovative therapy for wound repair, eliciting a positive therapeutic response across both stromal and epithelial tissue compartments of the skin. STATEMENT OF SIGNIFICANCE: This study advances research regarding the development of our unique electrospun nanofibre patch to deliver genetic nanoparticles into wounds in vivo to promote healing. The genetic nanoparticles are comprised of: (a) plasmid micro-RNA31 that has been shown to be downregulated in pathologies with delayed wound repair and (b) a 15 amino acid linear peptide termed CHAT. The CHAT facilitates complexation of miR-31 and cellular uptake. Herein, we report for the first time on the use of CHAT to deliver a therapeutic cargo pmiR-31 for wound healing applications from a nanofibre patch. Application of the nanofibre patch resulted in the controlled delivery of the CHAT/pmiR-31 nanoparticles with a significant increase in both epidermal and stratum corneum layers compared to untreated and commercial controls.

Autologous Fat Grafting - A Step Forward in Wound Management

Autologous fat grafting (AFG) is an emerging therapeutic option for wounds that are not ready for grafting. The regenerative potential of autologous fat lies in the adipose derived stem cells (ADSCs) contained within the stromal vascular fraction (SVF), which are capable of differentiating into multiple cell lineages. However to date, there has been no comprehensive evaluation of its efficacy in acute complicated wounds. This study aims to critically evaluate the efficacy and safety of AFG in cutaneous wound healing. Materials and Methods: This prospective, quasi experimental study was conducted in the Department Of Plastic Surgery, SIMS, Lahore, between June 2020 and June 2021. Thirty patients with pale granulation, not ready for grafting with no vital structure exposed were included in the study after detailed history, examination and were photographed pre and postoperatively. The procedure was performed under local anaesthesia. 40 to 80 ml fat was harvested from lower abdomen and after emulsification, placed over the wound wrapped in sufra tulle dressing. The dressing was changed on third postoperative day and outcome was assessed on clinical grounds. Results: Thirty patients (M:F Ratio 1.75:1) with mean age 30 years (Range 13-45 years) were included in this study with post traumatic (n = 23) and post infective (n = 7). Of 27 patients who completed their follow up, all had healthy granulation tissue which was later on grafted. Mean number of fat dressing sessions were 2 (Range 1-3). Conclusion: Autologous fat grafting has shown promising results for cutaneous wounds without any unacceptably high complication rates reported so far. Randomised controlled trials should be done on a larger scale to prove its efficacy in the management of complicated wounds.

Adipose-Derived Stem Cell: "Treat or Trick"

Stem cells have been widely used for treating disease due to the various benefits they offer in the curing process. Several treatments using stem cells have undergone clinical trials, such as cell-based therapies for heart disease, sickle cell disease, thalassemia, etc. Adipose-derived stem cells are some of the many mesenchymal stem cells that exist in our body that can be harvested from the abdomen, thighs, etc. Adipose tissue is easy to harvest, and its stem cells can be obtained in higher volumes compared to stem cells harvested from bone marrow, for which a more invasive technique is required with a smaller volume obtained. Many scientists have expressed interest in investigating the role of adipose-derived stem cells in treating disease since their use was first described. This is due to these stem cells' ability to differentiate into multiple lineages and secrete a variety of growth factors and proteins. Previous studies have found that the hormones, cytokines, and growth factors contained in adipose tissue play major roles in the metabolic regulation of adipose tissue, as well as in energy balance and whole-body homeostasis through their endocrine, autocrine, and paracrine functions. These are thought to be important contributors to the process of tissue repair and regeneration. However, it remains unclear how effective and safe ADSCs are in treating diseases. The research that has been carried out to date is in order to investigate the impact of ADSCs in disease treatment, as described in this review, to highlight its "trick or treat" effect in medical treatment.

A Systematic Review of Autologous Fat Grafting in the Treatment of Acute and Chronic Cutaneous Wounds

There is a growing interest in the regenerative potential of autologous fat. Adipose-derived stem cells, within the stromal vascular fraction of lipoaspirate samples, demonstrate anti-inflammatory, immunomodulatory, and angiogenic properties. This systematic review aimed to determine the efficacy and safety of autologous fat therapies for wound healing, with an evaluation of the quality of evidence provided by the literature.

Autologous fat grafting for the treatment of sclerotic lesions and scars

INTRODUCTION

Microfat grafting is a well-known technique that is underutilized in dermatology. Instead of removing sclerotic tissue, microfat grafting preserves the tissue and uses stem cells for remodeling its structure into normal tissue. We performed a retrospective study of patients treated with microfat grafting for sclerotic and atrophic skin lesions and scars.

PATIENTS AND METHODS

Seventy-two microfat grafts were performed using the Magalon technique under general anaesthesia for the treatment of sclerotic and atrophic skin lesions. We performed grafts for different indications, such as scars (n=55) and sclerotic and atrophic skin lesions (n=17: Parry-Romberg syndrome, morphea). The main outcome was assessed for satisfaction during follow-up. In addition, an independent committee judged the results based on photographs.

RESULTS

Satisfaction levels (e.g. results were judged to be "good") were almost 91% (n=50/55) for scars and 100% (n=17/17) for atrophic and sclerotic skin lesions. Satisfaction levels according to the independent committee were 94.1% for sclerotic and atrophic lesions and nearly 51% for scars.

CONCLUSION

Satisfaction was high after microfat grafting for atrophic and sclerotic skin lesions. Microfat grafting enabled restoration of the skin texture by exploiting stem cell properties. It is an efficient dermatological therapy for sclerotic and atrophic lesions, for which there are few alternative treatments.

Cell seeding accelerates the vascularization of tissue engineering constructs in hypertensive mice

Rapid blood vessel ingrowth into transplanted constructs represents the key requirement for successful tissue engineering. Seeding three-dimensional scaffolds with suitable cells is an approved technique for this challenge. Since a plethora of patients suffer from widespread diseases that limit the capacity of neoangiogenesis (e.g., hypertension), we investigated the incorporation of cell-seeded poly-L-lactide-co-glycolide scaffolds in hypertensive (BPH/2J, group A) and nonhypertensive (BPN/3J, group B) mice. Collagen-coated scaffolds (A1 and B1) were additionally seeded with osteoblast-like (A2 and B2) and mesenchymal stem cells (A3 and B3). After implantation into dorsal skinfold chambers, inflammation and newly formed microvessels were measured using repetitive intravital fluorescence microscopy for 2 weeks. Apart from a weak inflammatory response in all groups, significantly increased microvascular densities were found in cell-seeded scaffolds (day 14, A2: 192 ± 12 cm/cm², A3: 194 ± 10 cm/cm², B2: 249 ± 19 cm/cm², B3: 264 ± 17 cm/cm²) when compared with controls (A1: 129 ± 10 cm/cm², B1: 185 ± 8 cm/cm²). In this context, hypertensive mice showed reduced neoangiogenesis in comparison with nonhypertensive animals. Therefore, seeding approved scaffolds with organ-specific or pluripotent cells is a very promising technique for tissue engineering in hypertensive organisms.

Adipose-derived stem cells promote diabetic wound healing via the recruitment and differentiation of endothelial progenitor cells into endothelial cells mediated by the VEGF-PLCγ-ERK pathway

Adipose-derived stem cell (ADSC) therapy is a promising treatment strategy for wound healing; however, the mechanism underlying this effect remains unclear. In the present study, we aimed to explore the influence of ADSC-derived VEGF on diabetic wounds and its role in modulating endothelial progenitor cells. The effect of ADSCs and ADSC-derived VEGF in vivo was investigated using a diabetic wound healing model, and inflammatory factors, such as IL-6, IL-10, and TNF-α, were detected. RT-qPCR and western blot analysis were used to detect the expression of downstream targets. In addition, the role of ADSC-derived VEGF in modulating endothelial progenitor cells (EPCs) was investigated using EdU assay, CD-31 immunofluorescence, and Transwell assay in vitro. The results show that ADSCs accelerated diabetic wound tissue closure and decreased the expression of inflammatory factors, such as IL-6, IL-10, and TNF-α. Further molecular mechanism studies indicated that coculturing EPCs with ADSC--conditioned medium enhanced the proliferation, mobilization and differentiation of EPCs into endothelial cells. This enhancement was inhibited when the expression of the VEGF downstream signal molecules VEGFR2, PLCγ, and ERK1/ERK2 was blocked, indicating that ADSCs might accelerate diabetic wound healing through the recruitment and differentiation of EPCs mediated by VEGF. Overall, the results of the study revealed that ADSCs could promote diabetic wound healing through the recruitment and differentiation of EPCs via angiogenesis effects regulated by the VEGF-PLCγ-ERK1/ERK2 pathway and suppression of the inflammatory response. In addition, it will be helpful to establish further understanding of ADSC therapy for clinical application.

Role of stem cell therapies in treating chronic wounds: A systematic review

BACKGROUND

The impairment of cutaneous wound healing results in chronic, non-healing wounds that are caused by altered wound environment oxygenation, tissue injury, and permissive microbial growth. Current modalities for the treatment of these wounds inadequately address the complex changes involved in chronic wound pathogenesis. Consequently, stem cell therapies have emerged as a potential therapeutic modality to promote cutaneous regeneration through trophic and paracrine activity.

AIM

To investigate current literature regarding use of stem cell therapies for the clinical treatment of chronic, non-healing wounds.

METHODS

PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus were queried with combinations of the search terms “mesenchymal stem cells,” “adult stem cells,” “embryonic stem cells,” “erythroid precursor cells,” “stem cell therapies,” and “chronic wounds” in order to find relevant articles published between the years of 2000 and 2019 to review a 20-year experience. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved manuscripts (reviews, case reports/series, retrospective/prospective studies, and clinical trials) were evaluated by the authors for their depiction of clinical stem cell therapy use. Data were extracted from the articles using a standardized collection tool.

RESULTS

A total of 43 articles describing the use of stem cell therapies for the treatment of chronic wounds were included in this review. While stem cell therapies have been explored in in vitro and in vivo applications in the past, recent efforts are geared towards assessing their clinical role. A review of the literature revealed that adipose-derived stem cells, bone marrow-derived stem cells, bone marrow-derived mononuclear cells, epidermally-derived mesenchymal stem cells, fibroblast stem cells, keratinocyte stem cells, placental mesenchymal stem cells, and umbilical cord mesenchymal stem cells have all been employed in the treatment of chronic wounds of various etiologies. Most recently, embryonic stem cells have emerged as a novel stem cell therapy with the capacity for multifaceted germ cell layer differentiation. With the capacity for self-renewal and differentiation, stem cells can enrich existing cell populations in chronic wounds in order to overcome barriers impeding the progression of wound healing. Further, stem cell therapies can be utilized to augment cell engraftment, signaling and activity, and resultant patient outcomes.

CONCLUSION

Assessing observed clinical outcomes, potential for stem cell use, and relevant therapeutic challenges allows wound care stakeholders to make informed decisions regarding optimal treatment approaches for their patients’ chronic wounds.

Fat grafting and platelet-rich plasma for the treatment of diabetic foot ulcers: A feasibility-randomised controlled trial

Chronic, nonhealing diabetic foot ulcers (DFU) are increasing in prevalence and are often unresponsive to conventional therapy. Adipose tissue, containing adipose-derived stem cells, and platelet rich plasma (PRP) are regenerative therapies rich in growth factors which may provide a solution to chronic wound healing. This study aimed to assess the feasibility of conducting a definitive randomised controlled trial (RCT) to investigate the efficacy of these therapies for the treatment of DFU. This was a single centre, feasibility, three-arm, parallel group RCT. Eligible DFU patients were randomised on a 1:1:1 basis to three intervention arms: control (podiatry); fat grafting; fat grafting with PRP. The intervention was delivered once and patients were followed-up for 12 weeks. The primary objective was to assess measures of trial feasibility. Clinical outcomes and health-related quality of life (HRQoL) were also evaluated. Three hundred and thirty four patients were screened and 32 patients (9.6%) were deemed eligible with 18 enrolled in the trial (6 per arm) over 17 months. All participants completed the trial with no withdrawals or crossover. Participant engagement was high with most HRQoL questionnaires returned and only 4.8% follow-up appointments missed. There were five adverse events (AEs) related to the trial with no serious AEs. Five (28%) of the wounds healed. There was no difference between any of the groups in terms of clinical outcomes. This feasibility study demonstrated that a multi-centre RCT is safe and feasible with excellent patient engagement. We have highlighted crucial information regarding methodology and recruitment, which will guide future trial design. Registration number: NCT03085550 clinicaltrials.gov. Registered 01/03/2017.

In vitro Engineering of a Skin Substitute Based on Adipose-Derived Stem Cells

In the field of wound healing, stem cell-based strategies are gaining importance for their regenerative potential. Adipose-derived stem cells (ADSCs) are a particular subset of mesenchymal stem cells present in the stromal-vascular fraction of the adipose tissue, today considered very attractive for their relative abundance and accessibility in the human body. However, ADSCs are still not routinely used in normal clinical practice. Several studies have also reported ADSC transplantation in association with biomaterials in an attempt to enhance the local retention and growth rate of the cells. The aim of our study was to evaluate the ability of ADSCs to build a dermal scaffold to be potentially used as a dermal substitute in the field of wound healing, with optimal biocompatibility and mechanical properties. ADSCs were defined as CD90-, CD73-, and CD105-positive cells. ADSCs turned out to be capable of secreting all the main components of the extracellular matrix (ECM) upon stimulation, thus efficiently producing a collagen and fibronectin-containing dermal matrix. We also checked whether the ADSC-produced dermal scaffold could be seeded with keratinocytes. The scaffolding material directly produced by ADSCs has several advantages when compared to the commercially available ones: it is easily obtained from the patients and it is 100% biocompatible and supports cell-ECM interaction. Moreover, it represents a possible powerful therapeutic tool for patients with chronic ulcers since it appears to be potentially grafted with keratinocytes layers, thus bypassing the classical two-step grafting procedure.

Adipose-derived stem cells for treatment of chronic ulcers: current status

Chronic ulcers remain a difficult challenge in healthcare systems. While treatment options are limited, stem cells may be a novel alternative. Adipose-derived stem cells (ADSC) have become increasingly popular compared with bone marrow-derived stem cells as they are far easier to harvest. To summarize the current status of treating chronic ulcers with ADSC, this systematic review includes all clinical trials on the subject from PubMed and EmBase, as well as all registered clinical trials on ClinicalTrials.Gov. A total of nine clinical trials and fourteen registered trials were included. The studies were significantly different in terms of study design and patient population, and the overall quality of the studies was low to moderate. Despite the overall low study quality and the significant differences between the studies, some conclusions were consistent: ADSCs are safe, improve the healing of chronic ulcers, and reduce pain. As these results are consistent despite the shortcomings of the studies, they appear to highlight the efficacy of ADSCs in the treatment of chronic ulcers. Larger numbers of higher quality studies are needed to determine the precise role of ADSCs in treating chronic leg ulcers.

Skin Wound Healing: Refractory Wounds and Novel Solutions

This overview of the current state of skin wound healing includes in vitro and in vivo approaches along with some recent clinical trials. From an introduction to wound healing, to tissue engineering as applied to the skin, we cover the basis for the current wound care techniques as well as novel and promising approaches. Special emphasis is given to refractory wounds which include wounds in diabetic patients. Natural compounds have been ever present in wound healing, and so we devote a section to highlighting current attempts to understand their mechanisms and to use them in novel ways.