Mesenchymal stem cell in venous leg ulcer: An intoxicating therapy

An Evidence Map of Clinical Practice Guideline Recommendations and Quality on Venous Leg Ulcer

Significance: Venous leg ulcers (VLUs) are the most common venous disease, mainly presenting as open skin lesions on the legs or feet and are an important concern in clinical care settings. Recent Advances: Comprehensive tactics were employed to search electronic databases PubMed, Embase, guideline databases, and society websites were searched for Clinical Practice Guidelines (CPGs) on VLU care. The basic information, recommendations for the VLUs, methodological quality, and reporting quality of VLU's CPGs were extracted and captured in Excel. The quality of each CPG was independently assessed by four researchers using AGREE II instrument and the RIGHT checklist. Critical Issues: This study included 19 CPGs with a combined 23 recommendations. The assessment of VLUs was summarized based on the recommendations of VLUs in 11 major items; six on VLU's diagnosis and six on therapeutic strategies of VLUs. The identified CPGs were of mixed quality, and the highest score based on the scope and purpose was 82.85 ± 11.66, whereas the lowest mean score based on the editorial independence by AGREE II was 59.93 ± 21.50. Regarding the RIGHT checklist, field one (basic information) had the highest reporting rate (84.33%), whereas field five (review and quality assurance) had the lowest quality of CPGs (41.11%). Future Directions: This evidence map provided new perspectives in the presentation of evidence. In addition, the evidence map collected and evaluated the characteristics of published CPGs. Thus, the evidence map enhances our knowledge and promotes the development of trustworthy CPGs for VLUs.

Mesenchymal Stem Cell-Derived Extracellular Vesicles as an Advanced Therapy for Chronic Wounds

Chronic wounds are a significant challenge for patients, healthcare providers, and healthcare systems. Chronic wounds develop due to a complex interplay between chronic inflammation, tissue hypoxia, and oxidative stress, often occurring in the setting of advancing age. Ideally, new therapeutics should address all the components of chronic wound pathophysiology. Mesenchymal stem cell (MSC) therapies show significant promise to promote healing of chronic wounds. Extracellular vesicles (EVs) secreted by MSCs mediate many of their beneficial effects. We review the evidence demonstrating that MSC-EVs target the processes leading to chronic wounds. Additionally, we discuss how MSCs can be influenced to generate more potent wound healing EVs. Finally, we highlight the current state of EV clinical trials for wound healing and important preclinical studies that will lead to optimal use of MSC-EVs for patient care.

Strategies and challenges in the treatment of chronic venous leg ulcers

Evaluating patients with chronic venous leg ulcers (CVLUs) is essential to find the underlying etiology. The basic tenets in managing CVLUs are to remove the etiological causes, to address systemic and metabolic conditions, to examine the ulcers and artery pulses, and to control wound infection with debridement and eliminating excessive pressure on the wound. The first-line treatments of CVLUs remain wound care, debridement, bed rest with leg elevation, and compression. Evidence to support the efficacy of silver-based dressings in healing CVLUs is unavailable. Hydrogen peroxide is harmful to the growth of granulation tissue in the wound. Surgery options include a high ligation with or without stripping or ablation of the GSVs depending on venous reflux or insufficiency. Yet, not all CVLUs are candidates for surgical treatment because of comorbidities. When standard care of wound for 4 wk failed to heal CVLUs effectively, use of advanced wound care should be considered based on the available evidence. Negative pressure wound therapy facilitates granulation tissue development, thereby helping closure of CVLUs. Autologous split-thickness skin grafting is still the gold standard approach to close huge CVLUs. Hair punch graft appears to have a better result than traditional hairless punch graft for CVLUs. Application of adipose tissue or placenta-derived mesenchymal stem cells is a promising therapy for wound healing. Autologous platelet-rich plasma provides an alternative strategy for surgery for safe and natural healing of the ulcer. The confirmative efficacy of current advanced ulcer therapies needs more robust evidence.

Strategies and challenges in the treatment of chronic venous leg ulcers

Evaluating patients with chronic venous leg ulcers (CVLUs) is essential to find the underlying etiology. The basic tenets in managing CVLUs are to remove the etiological causes, to address systemic and metabolic conditions, to examine the ulcers and artery pulses, and to control wound infection with debridement and eliminating excessive pressure on the wound. The first-line treatments of CVLUs remain wound care, debridement, bed rest with leg elevation, and compression. Evidence to support the efficacy of silver-based dressings in healing CVLUs is unavailable. Hydrogen peroxide is harmful to the growth of granulation tissue in the wound. Surgery options include a high ligation with or without stripping or ablation of the GSVs depending on venous reflux or insufficiency. Yet, not all CVLUs are candidates for surgical treatment because of comorbidities. When standard care of wound for 4 wk failed to heal CVLUs effectively, use of advanced wound care should be considered based on the available evidence. Negative pressure wound therapy facilitates granulation tissue development, thereby helping closure of CVLUs. Autologous split-thickness skin grafting is still the gold standard approach to close huge CVLUs. Hair punch graft appears to have a better result than traditional hairless punch graft for CVLUs. Application of adipose tissue or placenta-derived mesenchymal stem cells is a promising therapy for wound healing. Autologous platelet-rich plasma provides an alternative strategy for surgery for safe and natural healing of the ulcer. The confirmative efficacy of current advanced ulcer therapies needs more robust evidence.

Autologous platelet-rich plasma injection enhances healing of chronic venous leg ulcer: A prospective randomised study

Our aim was to compare the efficacy and safety of platelet-rich plasma (PRP) application versus PRP injection for chronic venous leg ulcer (VLU) healing compared with compression therapy as a control. From July 2018 to December 2019, 90 chronic VLU patients were randomly assigned to PRP dressings (n = 30), local PRP injections (n = 30), and compression therapy alone (n = 30). Standard compression accompanied both PRP groups. The main endpoints were ulcer healing and area reduction within 3, 6, and 12 months. Complications and ulcer recurrence were also recorded. The study included 72 (80.0%) males and 18 (20.0%) females aged 22 to 66 years, having VLUs for 1 to 11 years. PRP injection promoted healing (24/30, 80%) more than PRP application (20/30, 66.7%) and compression (14/30, 46.7%), P = .007. Healing time was significantly shorter after PRP injection compared with the other two groups. A greater area reduction was observed after PRP injection compared with compression at all follow-up visits, P = .013, .002, and < .001, and compared with PRP application only at 3 months post-treatment, P = .016. Recurrence and complications were comparable among the groups. PRP injection enhances the healing of chronic venous ulcers more than each of PRP application and compression therapy. All had comparable recurrence and safety.

A topical cell therapy approach for diabetic chronic ulcers: Effects of mesenchymal stromal cells associated with platelet-rich plasma

BACKGROUND

Diabetic cutaneous ulcers are subjected to several physiological and biochemical defects, which contribute to wound chronicity and therapeutic failure. Platelet-rich plasma (PRP) has been used for stimulating tissue regeneration, and mesenchymal stromal cells (MSCs) have demonstrated therapeutic properties in all phases of skin regeneration in cell therapy studies.

AIMS

The objective of this study was to evaluate the therapeutic effects related to the use of a biomembrane composed of autologous MSCs and PRP on chronic wounds of diabetic patients (pre-post pilot study).

PATIENTS/METHODS

Six diabetic patients with chronic wounds for more than 6 months were subjected to adipose tissue collection for isolation of MSCs, blood collection for PRP preparation, and topical administration of a biomembrane of MSCs and PRP on each chronic wound. The statistical difference regarding the evolution of ulcers was calculated by means of paired t test.

RESULTS

There was granulation tissue formation starting from 7 days after topical application. Total re-epithelialization occurred in 5 of the 9 lesions treated, and the mean wound healing rate (WHR) was 74.55% (±32.55%) after 90 days. No cicatricial hypertrophy or retraction was observed.

CONCLUSION

Mesenchymal stromal cells topical therapy associated with PRP is well-tolerated and able to provide a reduction in ulcer area of diabetic chronic wounds.

Can supernatant from immortalized adipose tissue MSC replace cell therapy? An in vitro study in chronic wounds model

Background

Mesenchymal stem cells (MSCs) secrete a cocktail of growth factors and cytokines, which could promote tissue regeneration and wound healing. Therefore, in clinical practice, post-culture MSC supernatant treatment could be a more attractive alternative to autologous stem cell transplantation. In this study, we compared the regenerative properties of supernatants harvested from four newly established human adipose tissue mesenchymal stem cell lines (HATMSCs) derived from chronic wound patients or healthy donors.

Methods

HATMSC supernatants were produced in a serum-free medium under hypoxia and their content was analyzed by a human angiogenesis antibody array. The regenerative effect of HATMSCs supernatants was investigated in an in vitro model of chronic wound, where cells originating from human skin, such as microvascular endothelial cells (HSkMEC.2), keratinocytes (HaCaT), and fibroblasts (MSU-1.1), were cultured in serum-free and oxygen-reduced conditions. The effect of supernatant treatment was evaluated using an MTT assay and light microscopy. In addition, fibroblasts and HATMSCs were labeled with PKH67 and PKH26 dye, respectively, and the effect of supernatant treatment was compared to that obtained when fibroblasts and HATMSCs were co-cultured, using flow cytometry and fluorescent microscopy.

Results

A wide panel of angiogenesis-associated cytokines such as angiogenin, growth-regulated oncogene (GRO), interleukin-6 and 8 (IL-6, IL-8), vascular endothelial growth factor (VEGF), insulin growth factor 1 (IGF-1), and matrix metalloproteinase (MMP) were found in all tested HATMSCs supernatants. Moreover, supernatant treatment significantly enhanced the survival of fibroblasts, endothelial cells, and keratinocytes in our chronic wound model in vitro. Importantly, we have shown that in in vitro settings, HATMSC supernatant treatment results in superior fibroblast proliferation than in the case of co-culture with HATMSCs.

Conclusions

Our results suggest that therapy based on bioactive factors released by the immortalized atMSC into supernatant has important effect on skin-derived cell proliferation and might preclude the need for a more expensive and difficult cell therapy approach to improve chronic wound healing.

Iron and iron-dependent reactive oxygen species in the regulation of macrophages and fibroblasts in non-healing chronic wounds

Chronic wounds pose a stern challenge to health care systems with growing incidence especially in the aged population. In the presence of increased iron concentrations, recruitment of monocytes from the circulation and activation towards ROS and RNS releasing M1 macrophages together with the persistence of senescent fibroblasts at the wound site are significantly enhanced. This unrestrained activation of pro-inflammatory macrophages and senescent fibroblasts has increasingly been acknowledged as main driver causing non-healing wounds. In a metaphor, macrophages act like stage directors of wound healing, resident fibroblasts constitute main actors and increased iron concentrations are decisive parts of the libretto, and - if dysregulated - are responsible for the development of non-healing wounds. This review will focus on recent cellular and molecular findings from chronic venous leg ulcers and diabetic non-healing wounds both constituting the most common pathologies often resulting in limb amputations of patients. This not only causes tremendous suffering and loss of life quality, but is also associated with an increase in mortality and a major socio-economic burden. Despite recent advances, the underlying molecular mechanisms are not completely understood. Overwhelming evidence shows that reactive oxygen species and the transition metal and trace element iron at pathological concentrations are crucially involved in a complex interplay between cells of different histogenetic origin and their extracellular niche environment. This interplay depends on a variety of cellular, non-cellular biochemical and cell biological mechanisms. Here, we will highlight recent progress in the field of iron-dependent regulation of macrophages and fibroblasts and related pathologies linked to non-healing chronic wounds.

Autologous bone marrow-derived cells for venous leg ulcers treatment: a pilot study

BACKGROUND

Chronic venous leg ulcers (VLUs) are a common problem in clinical practice and available treatments are not satisfactory. The use of adjuvant therapies in combination with lower limb compression may lead to improved healing rates. Chronic wounds are candidates for new strategies in the emergent field of regenerative medicine. Bone marrow-derived cells (BMDCs) contain cells and secrete cytokines known to participate in wound healing. Thus, BMDC therapy seems a logical strategy for the treatment of chronic wounds. Our objective was to evaluate feasibility, safety and initial clinical outcome of autologous BMDC therapy associated with standard treatment in patients with VLUs.

METHODS

We conducted an open-label, single-arm, prospective pilot clinical trial in four patients with six chronic VLUs. The study protocol was approved by the institutional and national review boards and ethics committees. Bone marrow was harvest, processed and then administered by multiple injections into the ulcers. All patients received standard treatment and non-healing characteristics of the VLUs were confirmed at study entry.

RESULTS

Ulcer size and wound pain evaluated 12 months after BMDC treatment were significantly reduced (P < 0.05). BMDC treatment was safe and well tolerated in long-term follow-up.

DISCUSSION

Despite the low number of patients studied, our results showed that autologous BMDC treatment could be a useful, feasible and safe procedure to enhance ulcer healing. However, randomized controlled trials with more patients are needed to address this question and translate this approach into clinical practice.

Autologous Platelet-Rich Plasma Reduces Healing Time of Chronic Venous Leg Ulcers: A Prospective Observational Study

The study investigated whether the application of dressings with autologous platelet-rich plasma (PRP) would reduce the healing time in patients with chronic venous leg ulcers. This is a prospective observational study that included 100 patients diagnosed with lower extremity venous insufficiency complicated by ulceration of a leg or foot, who had been after angioplasty of stenotic artery. Patients were divided into two groups of 50 each: treated with PRP (study group) and treated with conventional hydrocolloid dressings (control group). We followed the wound changes at Day 10, Day 20, and Day 30 of treatment and compared them with the baseline appearance at Day 0. We evaluated the appearance, area, and depths of wounds with ultrasound. The granulation process was examined histologically to document skin formation and wound tissue neovascularization. The findings were that treatment with PRP dressings resulted in a significant progressive reduction in ulcer size, irrespective of the ulcer's initial size, compared to treatment with conventional dressings. Further, the best effect of PRP was noticed in the category of largest wounds. After a month of treatment with PRP dressings, more than 50% of all ulcers were completely healed. The young epidermis appeared together with the granulation tissue, and the formation of dermis took shape after 20 days of treatment. We conclude that the use of PRP dressings is a safe, nonsurgical adjunctive procedure for treating chronic venous leg ulcers. The potential benefit of PRP dressings over conventional ulcer treatment requires further in-depth exploration.

A phase II randomized clinical trial for the treatment of recalcitrant chronic leg ulcers using centrifuged adipose tissue containing progenitor cells

BACKGROUND AIMS

Preclinical and observational reports indicate that adipose tissue (AT) is a safe and promising tool to treat non-healing venous leg ulcers (VLUs).

METHODS

From an initial cohort of 38 patients, 16 patients affected by non-healing VLUs were randomly allocated to the experimental arm (5 men and 3 women) and control arm (5 men and 3 women). In the experimental arm, wounds were treated by debridement, centrifuged adipose tissue (CAT), advanced dressings and compression. No experimental treatment (CAT) was administered to the control arm. We investigated the functional and the immunophenotypical features of the harvested CAT-derived stem cells. The primary outcome measures were healing time and safety of the cell treatment. Secondary outcomes were pain evaluated by numeric rating scale (NRS), complete wound healing at 24 weeks by Margolis Index and wound-healing process expressed in square centimeters per week. The various immunophenotypic and functional characteristics of CAT-derived stem cells were then correlated with the clinical outcomes.

RESULTS

No major adverse events were recorded. The healing time was significantly faster by applying CAT, 17.5 ± 7.0 weeks versus 24.5 ± 4.9 weeks recorded in the control arm (P < 0.036). NRS dropped after the first week to 2.7 ± 2.0 in the experimental arm versus 6.6 ± 3.0 in the control group (P < 0.01). The rate of healing at the 24th week was not significantly different between arms. Interestingly, we found a strong reverse correlation between the percent of CD34⁺/CD45^- non-hematopoietic cells, respectively, with the healing time (r = -0.894, P < 0.041) and NRS (r = -0.934, P < 0.020).

CONCLUSIONS

CAT is safe and may accelerate healing time in VLUs as well as reduce wound pain. The percentage of CD34⁺/CD45^- cells in stromal vascular fraction (SVF) seems to be a predictive biomarker of successful CAT treatment in these patients.

Current Therapeutic Strategies for Stem Cell-Based Cartilage Regeneration

The process of cartilage destruction in the diarthrodial joint is progressive and irreversible. This destruction is extremely difficult to manage and frustrates researchers, clinicians, and patients. Patients often take medication to control their pain. Surgery is usually performed when pain becomes uncontrollable or joint function completely fails. There is an unmet clinical need for a regenerative strategy to treat cartilage defect without surgery due to the lack of a suitable regenerative strategy. Clinicians and scientists have tried to address this using stem cells, which have a regenerative potential in various tissues. Cartilage may be an ideal target for stem cell treatment because it has a notoriously poor regenerative potential. In this review, we describe past, present, and future strategies to regenerate cartilage in patients. Specifically, this review compares a surgical regenerative technique (microfracture) and cell therapy, cell therapy with and without a scaffold, and therapy with nonaggregated and aggregated cells. We also review the chondrogenic potential of cells according to their origin, including autologous chondrocytes, mesenchymal stem cells, and induced pluripotent stem cells.