The safety and efficacy of mesenchymal stem cell therapy in diabetic lower extremity vascular disease: a meta-analysis and systematic review

Stem Cell Therapy for Diabetic Foot: An Umbrella Review of Systematic Reviews and Meta-Analyses

Objective: This umbrella review aims to summarize and evaluate the evidence from current systematic reviews/meta-analyses (SRs/MAs) on the effectiveness of stem cell therapy for diabetic foot (DF). Approach: We conducted a comprehensive search in four databases for SRs/MAs that included randomized controlled trials (RCTs) on stem cell therapy for DF. Two separate researchers independently evaluated the methodological quality and evidence quality of the SRs/MAs that were included in the study. We conducted a quantitative synthesis of all RCTs included in the SRs/MAs to obtain objective and updated conclusions. Egger's test and sensitivity analysis are used to examine the reliability of the results. Results: This umbrella review includes eight SRs/MAs, and their methodological quality and evidence quality were all deemed unsatisfactory. Out of the 8 SRs/MAs, 26 RCTs were included, with a total corrected covered area of 21.4%, indicating a high degree of overlap. The test of super-significance did not yield any significant results. Our updated meta-analysis suggests that DF patients can benefit from stem cell therapy, as indicated by effectiveness in measures, including healing rate, amputation rate, ankle-brachial index, transcutaneous oxygen pressure, ulcer size reduction, complete healing time, pain-free walking distance, rest pain score, and new angiogenesis rate. Innovation: This study conducted a comprehensive evaluation and reanalysis of the current evidence regarding the effectiveness and safety of stem cell therapy for DF, which is the first of its kind. Conclusion: Based on the existing evidence, stem cell therapy is effective and safe for patients with DF.

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.

Roles and mechanisms of umbilical cord mesenchymal stem cells in the treatment of diabetic foot: A review of preclinical and clinical studies

AIMS

Growing preclinical and clinical evidence has suggested the potential method of umbilical cord mesenchymal stem cell (UCMSC) therapy for diabetic foot. Thus, the authors provided an outline of the application of UCMSCs in the treatment of diabetic foot and further summarized the roles and mechanisms of this therapy.

DATA SYNTHESIS

With no time limitations, the authors searched the Web of Science, Cochrane Central Register of Controlled Trials, and PubMed (MEDLINE) databases. 14 studies were included, including 9 preclinical experiments and 5 clinical trials (3 RCTs and 2 single-arm trials).

CONCLUSIONS

The UCMSCs are of great efficacy and safety, and function mainly by reducing inflammation, regulating immunity, promoting growth factors, and enhancing the functions of vascular endothelial cells, fibroblasts, and keratinocytes. As a result, ulcer healing-related biological processes ensue, which finally lead to diabetic foot ulcer healing and clinical symptom improvement. UCMSC treatment enhances diabetic foot ulcer healing and has a safety profile. They function mainly by modulating immunity, promoting growth factor secretion, and enhancing cellular functions. More well-designed preclinical and clinical studies are needed to provide the most optimal protocol, the comprehensive molecular mechanisms, as well as to further evaluate the efficiency and safety profile of UCMSC treatment in diabetic foot patients.

A novel therapeutic management for diabetes patients with chronic limb-threatening ischemia: comparison of autologous bone marrow mononuclear cells versus allogenic Wharton jelly-derived mesenchymal stem cells

BACKGROUND

Chronic limb-threatening ischemia (CLTI) represents the final stage of peripheral arterial disease. Approximately one-third of patients with CLTI are not eligible for conventional surgical treatments. Furthermore, patients with advanced stage of CLTI are prone to amputation and death. Thus, an effective therapeutic strategy is urgently needed. In this context, autologous bone marrow mononuclear cell (auto-BM-MNC) and allogeneic mesenchymal stem cells represent a promising therapeutic approach for treating CLTI. In this study, we compared the safety and beneficial therapeutic effect of auto-BM-MNC versus allogeneic Wharton jelly-derived mesenchymal stem cells (allo-WJ-MSCs) in diabetic patients with CLTI.

METHODS

We performed a randomized, prospective, double-blind and controlled pilot study. Twenty-four diabetic patients in the advanced stage of CLTI (4 or 5 in Rutherford's classification) and a transcutaneous oxygen pressure (TcPO2) below 30 mmHg were randomized to receive 15 injections of (i) auto-BM-MNC (7.197 × 106 ± 2.984 × 106 cells/mL) (n = 7), (ii) allo-WJ-MSCs (1.333 × 106 cells/mL) (n = 7) or (iii) placebo solution (1 mL) (n = 10), which were administered into the periadventitial layer of the arterial walls under eco-Doppler guidance. The follow-up visits were at months 1, 3, 6, and 12 to evaluate the following parameters: (i) Rutherford's classification, (ii) TcPO2, (iii) percentage of wound closure, (iv) pain, (v) pain-free walking distance, (vi) revascularization and limb-survival proportion, and (vii) life quality (EQ-5D questionnaire).

RESULTS

No adverse events were reported. Patients with CLTI who received auto-BM-MNC and allo-WJ-MSCs presented an improvement in Rutherford's classification, a significant increase in TcPO2 values‬, a reduction in the lesion size in a shorter time, a decrease in the pain score and an increase in the pain-free walking distance, in comparison with the placebo group. In addition, the participants treated with auto-BM-MNC and allo-WJ-MSCs kept their limbs during the follow-up period, unlike the placebo group, which had a marked increase in amputation.

CONCLUSIONS

Our results showed that patients with CLTI treated with auto-BM-MNC and allo-WJ-MSCs conserved 100% of their limb during 12 months of the follow-up compared to the placebo group, where 60% of participants underwent limb amputation in different times. Furthermore, we observed a faster improvement in the allo-WJ-MSC group, unlike the auto-BM-MNC group. Trial registration This study was retrospectively registered at ClinicalTrials.gov (NCT05631444).

Therapeutic Benefits of Stem Cells and Exosomes for Sulfur-Mustard-Induced Tissue Damage

Sulfur mustard (SM) is a highly toxic chemical agent that causes severe tissue damage, particularly to the eyes, lungs, and skin. Despite advances in treatment, there is a need for more effective therapies for SM-induced tissue injury. Stem cell and exosome therapies are emerging as promising approaches for tissue repair and regeneration. Stem cells can differentiate into multiple cell types and promote tissue regeneration, while exosomes are small vesicles that can deliver therapeutic cargo to target cells. Several preclinical studies demonstrated the potential of stem cell, exosome, or combination therapy for various tissue injury, showing improvements in tissue repairing, inflammation, and fibrosis. However, there are also challenges associated with these therapies, such as the requirement for standardized methods for exosome isolation and characterization, the long-term safety and efficacy and reduced SM-induced tissue injury of these therapies. Stem cell or exosome therapy was used for SM-induced eye and lung injury. Despite the limited data on the use for SM-induced skin injury, this therapy is a promising area of research and may offer new treatment options in the future. In this review, we focused on optimizing these therapies, evaluating their safety and efficacy, and comparing their efficacy to other emerging therapeutic approaches potentially for SM-induced tissue injury in the eye, lung, and skin.

GelMA Hydrogel Loaded with Extracellular Vesicles Derived from Umbilical Cord Mesenchymal Stem Cells for Promoting Cutaneous Diabetic Wound Healing

Chronic diabetic wounds have become a significant cause of disability worldwide. It is highly desired to develop effective therapies that can promote the rapid healing of diabetic wounds. Owing to the outstanding hydrophilic and water-retaining properties, hydrogels could accelerate the healing process. Extracellular vesicles (EVs) have shown the ability to promote cell regeneration and angiogenesis. In this study, we chose a gelatin methacryloyl (GelMA) hydrogel, a kind of biomaterial characteristic of good biocompatibility, to load the EVs derived from umbilical cord mesenchymal stem cells (UCMSCs) in order to have a long-lasting effect by consistent release of EVs. Then, the hydrogel with EVs was used to treat diabetic wounds in rat models. Nuclear magnetic resonance spectroscopy and scanning electron microscopy were used to characterize the synthesis of the hydrogel; cell experiments, animal experiments, and histological staining were used to evaluate the function of the hydrogel with EVs. The results show that the GelMA hydrogel incorporated with the UCMSC-derived EVs exhibits unique physicochemical properties, excellent biocompatibility, and much enhanced therapeutic effects for diabetic wounds.

Progress and expectation of stem cell therapy for diabetic wound healing

Impaired wound healing presents great health risks to diabetics. Encouragingly, the current clinical successfully found out meaningful method to repair wound tissue, and stem cell therapy could be an effective method for diabetic wound healing with its ability to accelerate wound closure and avoid amputation. This minireview aims at introducing stem cell therapy for facilitating tissue repair in diabetic wounds, discussing the possible therapeutic mechanism and clinical application status and problems.