Efficacy of Cellular Therapy for Diabetic Foot Ulcer: A Meta-Analysis of Randomized Controlled Clinical Trials

Efficacy of stem cell therapy for diabetic foot: Clinical evidence from meta-analyses

To assess the clinical data on the effectiveness of stem cell therapy for diabetic foot (DF) based on recent systematic reviews and meta-analyses (SRs/MAs). SRs/MAs that evaluate the clinical evidence on the efficacy of stem cell therapy for DF were identified through a systematic search in public databases. The methodological quality and evidence quality of the included SRs/MAs were assessed separately by two researchers. Eight SRs/MAs were included in this analysis. Since there were no registered protocol or exclusion criteria for the included SRs/MAs, the methodological quality was rated as critically low. There was no high-quality evidence available for the outcomes, and the evidence quality ranged from critically low to moderate. Evidence degradation was most commonly caused by the risk of bias, followed by imprecision, publication bias and inconsistency. In conclusion, stem cell therapy may be effective for DF. However, this conclusion should be approached with caution, considering the quality of the supporting SRs/MAs.

The Immune-Centric Revolution in the Diabetic Foot: Monocytes and Lymphocytes Role in Wound Healing and Tissue Regeneration-A Narrative Review

Monocytes and lymphocytes play a key role in physiologic wound healing and might be involved in the impaired mechanisms observed in diabetes. Skin wound macrophages are represented by tissue resident macrophages and infiltrating peripheral blood recruited monocytes which play a leading role during the inflammatory phase of wound repair. The impaired transition of diabetic wound macrophages from pro-inflammatory M1 phenotypes to anti-inflammatory pro-regenerative M2 phenotypes might represent a key issue for impaired diabetic wound healing. This review will focus on the role of immune system cells in normal skin and diabetic wound repair. Furthermore, it will give an insight into therapy able to immuno-modulate wound healing processes toward to a regenerative anti-inflammatory fashion. Different approaches, such as cell therapy, exosome, and dermal substitute able to promote the M1 to M2 switch and able to positively influence healing processes in chronic wounds will be discussed.

Recent advances in the induced pluripotent stem cell-based skin regeneration

Skin regeneration has been a challenging clinical problem especially in cases of chronic wounds such as diabetic foot ulcers, and epidermolysis bullosa-related skin blisters. Prolonged non-healing wounds often lead to bacterial infections increasing the severity of wounds. Current treatment strategies for chronic wounds include debridement of wounds along with antibiotics, growth factors, and stem cell transplantation therapies. However, the compromised nature of autologous stem cells in patients with comorbidities such as diabetes limits the efficacy of the therapy. The discovery of induced pluripotent stem cell (iPSC) technology has immensely influenced the field of regenerative therapy. Enormous efforts have been made to develop integration-free iPSCs suitable for clinical therapies. This review focuses on recent advances in the methods and reprogramming factors for generating iPSCs along with the existing challenges such as genetic alterations, tumorigenicity, immune rejection, and regulatory hurdles for the clinical application of iPSCs. Furthermore, this review also highlights the benefits of using iPSCs for the generation of skin cells and skin disease modeling over the existing clinical therapies for skin regeneration in chronic wounds and skin diseases.

Nonpharmacological Management of Diabetic Foot Ulcers: An Update

Diabetic foot ulcers (DFUs) are a common and serious complication of diabetes mellitus that is associated with increased morbidity and mortality, as well as substantial economic burden for the health care system. The standard of care for DFUs includes pressure off-loading, sharp debridement, and wound moisture balance, along with infection control and management of peripheral arterial disease. A variety of advanced modalities that target distinct pathophysiological aspects of impaired wound healing in diabetes are being studied as possible adjunct therapies for difficult to heal ulcers. These modalities include growth factors, stem cells, cultured fibroblasts and keratinocytes, bioengineered skin substitutes, acellular bioproducts, human amniotic membranes, oxygen therapy, negative pressure wound therapy, and energy therapies. Additionally, the use of advanced biomaterials and gene delivery systems is being investigated as a method of effective delivery of substances to the wound bed. In the present narrative review, we outline the latest advances in the nonpharmacological management of DFUs and summarize the efficacy of various standard and advanced treatment modalities.

Adipose-Derived Mesenchymal Stem Cells in the Treatment of Diabetic Foot Ulcers: A Review of Preclinical and Clinical Studies

This review provides an outline of the use of adipose-derived mesenchymal stem cells (AMSCs) in the treatment of diabetic foot ulcers (DFUs). A systematic search of PubMed and the Cochrane database was performed on October 2, 2019. Eighteen studies were identified (14 preclinical and 4 clinical). Studies in animal models have demonstrated that AMSCs enhance diabetic wound healing, accelerate granulation tissue formation, and increase reepithelialization and neovascularization. Only 1 randomized control trial has been published so far. Patients (n = 25) with DFUs were treated using an allogeneic AMSC directly on the wound bed as a primary dressing, and improvements were found in complete wound closure in the treatment group (n = 16). Three clinical studies showed that autologous AMSC might be a safe alternative to achieve therapeutic angiogenesis in patients with diabetes and peripheral arterial disease. Based on the available evidence, AMSCs hold promise in the treatment of DFUs. However, this evidence requires confirmation by well-designed trials. Additional studies are also required to understand some issues regarding this treatment for DFUs. For example, the potential application of autologous or allogeneic AMSCs in different types of DFUs, optimal dose/infusion schedules, safety evaluations, and cost-effectiveness.

Model-Based Analysis Reveals a Sustained and Dose-Dependent Acceleration of Wound Healing by VEGF-A mRNA (AZD8601)

Intradermal delivery of AZD8601, an mRNA designed to produce vascular endothelial growth factor A (VEGF‐A), has previously been shown to accelerate cutaneous wound healing in a murine diabetic model. Here, we develop population pharmacokinetic and pharmacodynamic models aiming to quantify the effect of AZD8601 injections on the dynamics of wound healing. A dataset of 584 open wound area measurements from 131 mice was integrated from 3 independent studies encompassing different doses, dosing timepoints, and number of doses. Evaluation of several candidate models showed that wound healing acceleration is not likely driven directly by time‐dependent VEGF‐A concentration. Instead, we found that administration of AZD8601 induced a sustained acceleration of wound healing depending on the accumulated dose, with a dose producing 50% of the maximal effect of 92 µg. Simulations with this model showed that a single dose of 200 µg AZD8601 can reduce the time to reach 50% wound healing by up to 5 days.

Surgical Offloading Techniques Should be Used More Often and Earlier in Treating Forefoot Diabetic Ulcers: An Evidence-Based Review

Conservative treatment is the basis for diabetic foot ulcer (DFU) management, whereas surgical treatment is usually reserved for patients with failed, recurrent, or nonresponsive infected wounds. However, many reports demonstrated good to excellent results following surgery. Evidence synthesis on surgical offloading techniques and clear guidelines regarding the timing of surgery are lacking. The present study aimed to investigate the evidence behind surgical offloading techniques and propose a cutoff time for surgical indication following failed conservative treatment of neuropathic diabetic forefoot ulcers. Electronic databases were searched from inception to identify the best evidence level articles related to non-vascular surgical treatment of DFUs, such as metatarsal head resection, resection arthroplasty, metatarsal osteotomy, Achilles tendon lengthening, gastrocnemius recession, and flexor tenotomy, that have been employed for managing DFUs. Based on the highest level of evidence available, surgery was found to generate better values than standard conservative care for all outcomes except for the transfer rate. In particular, surgical bony offloading procedures demonstrated significantly better outcomes than standard conservative nonsurgical care in terms of higher healing rates, shorter healing durations, and lower recurrence rates. Moreover, 96% of DFUs healed in <1 month following surgical bony offloading, whereas 68% of ulcers healed within 3 months after standard care. The findings could challenge the classical guidelines of DFU management. This evidence-based review indicates that surgical offloading could be used more often and be proposed earlier during the course of ulcer management. The results imply that a period of 12 weeks could be considered a reasonable cutoff value to consider surgical treatment for patients with nonhealing DFUs.

Role of platelet-rich plasma in healing diabetic foot ulcers: a prospective study

OBJECTIVE

To evaluate the role of platelet-rich plasma (PRP) in healing diabetic fool ulcers (DFUs), and to compare the rate of healing and final outcome with conventional therapy.

METHOD

A prospective study conducted between October 2013 and July 2015. Participants were divided in to two groups: a study group in which PRP was used and a control group receiving standard therapy. Wound assessment was carried out according to the Bates-Jensen Wound Assessment Tool at 0, 7, 14, 21 and 28 days.

RESULTS

A total of 55 patients were recruited to the study. There were 29 patients in the study group and 26 patients in the control group. After application of PRP, there was significant improvement in mean wound score and significant percent improvement in wound score in the study group (p<0.0001). Complete healing occurred in all patients in the study group in (mean score and standard deviation) 36.7±3 days compared with 60.6±3.7 days in the control group (p<0.0001). There were no unwanted side effects in patients using the PRP in this study.

CONCLUSION

PRP appears to be a promising agent in the management of DFUs. In this study, DFUs healed more quickly in the study group than in the control group. There was also significant percent improvement in wound score as compared with debridement and dressing only. If proper selection criteria are applied, PRP could be a useful aid to wound healing in people with DFUs.

Effect of Induced Membrane Formation Followed by Polymethylmethacrylate Implantation on Diabetic Foot Ulcer Healing When Revascularization Is Not Feasible

No study has investigated the role of induced membrane (IM) formation in treating diabetic foot ulcer (DFU). This retrospective study was aimed (1) at evaluating the potential role of a two-staged surgical approach, comprising polymethylmethacrylate (PMMA) implantation and IM formation, in the treatment of DFU and (2) at comparing the results of those with routine wound debridement in patients with DFUs and nonrevascularized peripheral arterial disease (PAD). Fifty patients with infected DFUs who were not candidates for vascular interventions were enrolled between February 2016 and April 2018 and assigned to the PMMA group (n = 28) and conventional group (n = 22). The healing rate, major amputation rate, duration of healing, frequency of debridement procedures, patient survival rate, and reulceration of DFUs were determined. The Mann-Whitney U test, independent sample t-test, and χ ² or Fisher exact test were used in statistical analysis. Overall clinical outcomes were statistically different between the groups (Z = -2.495, P = 0.013). In the PMMA group, 16 patients (57.1%) with intact IM formation achieved ulceration healing at 13.1 ± 3.7 weeks with a mean number of debridements of 1.3 ± 0.4, which were significantly different compared to those values in 5 patients of the conventional group (22.7%, P = 0.014; healing duration: 26.4 ± 7.8 weeks, P = 0.016; mean number of debridements: 3.6 ± 0.5, P ≤ 0.001). At a mean 16.8 ± 4.3-month follow-up, patient survival rates were 92.9% and 68.2% in the PMMA and conventional groups, respectively (P = 0.032). The major amputation rate and reulceration of DFUs were similar between the groups. The two-staged surgical approach is an available, effective modality for improving healing of DFUs. This study provides preliminary information of IM formation followed by PMMA implantation in the management of DFUs in PAD when revascularization is not feasible.