Both autologous bone marrow mononuclear cell and peripheral blood progenitor cell therapies similarly improve ischaemia in patients with diabetic foot in comparison with control treatment

Impacts of stem cells from different sources on wound healing rate in diabetic foot ulcers: a systematic review and meta-analysis

Background

Diabetic foot ulcers (DFU) are a significant complication of diabetes, with huge implications on patient morbidity and healthcare costs. The objective of this meta-analysis was to evaluate the impacts of stem cells from different sources on wound healing rate in DFU patients.

Methods

We systematically retrieved records via key databases PubMed, Cochrane Library, Web of Science, Embase, China National Knowledge Infrastructure (CNKI) and Wanfang from the inception to October 2024. The Stata 16.0 (Stata Corp, TX) software was used to perform the meta-analysis. Risk of bias in all included studies was evaluated by Cochrane Risk of Bias version 2.

Results

A total of 24 studies involving 1,321 patients were included. There was an increased likelihood of wound healing with peripheral blood-derived stem cells, the most effective cells (odds ratios (OR) = 7.31, 95% CI: 2.90-18.47), followed by adipose-derived stem cells (OR = 5.23, 95% CI: 2.76-9.90), umbilical cord-derived stem cells (OR = 4.94, 95% CI: 0.61-40.03), bone-derived stem cells (OR = 4.36, 95% CI: 2.43-7.85) and other sources stem cells (OR = 3.16, 95% CI: 1.83-5.45). Nevertheless, only umbilical cord-derived stem cells showed statistical significance (p < 0.05). The heterogeneity ranged from non-existent in the adipose and peripheral blood groups (I2 = 0.00%) to moderate in the bone groups (I2 = 26.31%) and other groups (I2 = 30.62%), and substantial in the umbilical cord groups (I2 = 88.37%). Asymmetrical funnel plots pointed to publication bias, but the trim-and-fill method to correct for this brought the effect estimates even lower: based on the pooled OR, corrected OR was 3.40 (95% CI 2.39-4.84). Stem cell therapy was also associated with improvements in several secondary outcomes, suggesting its potential to influence the progression of DFU.

Conclusion

Our study suggested that stem cells from different sources showed potential in promoting wound healing in DFU, although with some variation in effectiveness. Despite some publication bias and moderate heterogeneity, the overall therapeutic effect remained positive. These findings indicated that stem cell therapy might influence the progression of DFU.

Purified CD34+ Cells Transplantation in Patients with Angiitis-Induced Chronic Limb-Threatening Ischemia: A Single-Center Retrospective Study over a 10-Year Period

BACKGROUND

Angiitis-induced chronic limb-threatening ischemia (AICLTI) is defined as chronic limb-threatening ischemia caused by thromboangiitis obliterans or other arteritis-related autoimmunological diseases. In the current study, we aimed to report the 10-year outcomes of AICLTI patients who underwent purified cluster of differentiation 34 positive (CD34+) cells (PCCs) transplantation.

METHODS

AICLTI patients who underwent PCCs transplantation at our center from May 2009 to September 2011 were retrospectively enrolled. The main outcome was major amputation-free survival (MAFS); other outcomes included Rutherford classification, intolerable pain-free walking time, Wong-Baker Faces Pain Rating Scale, recurrence, new lesions, quality of life and patients' posttransplantation work conditions.

RESULTS

Twenty-four patients were enrolled with a mean age of 41.5 ± 7.8 years. Three underwent major amputation during the follow-up, and the 10-year MAFS was 87.5%. Eight were observed to have recurrence, and 2 had new lesions; the 10-year recurrence-free rate was 66.1%. All patients were unable to work at admission, 17 (70.8%) patients were reemployed after transplantation.

CONCLUSIONS

The current study further demonstrated satisfactory long-term efficacy of PCCs transplantation, with a 10-year MAFS of 87.5%. However, the 10-year recurrence-free rate of 66.1% suggested that strict and regular long-term follow-up is necessary.

The Immune-Centric Revolution Translated into Clinical Application: Peripheral Blood Mononuclear Cell (PBMNC) Therapy in Diabetic Patients with No-Option Critical Limb-Threatening Ischemia (NO-CLTI)-Rationale and Meta-Analysis of Observational Studies

Chronic limb-threatening ischemia (CLTI), the most advanced form of peripheral arterial disease (PAD), is the comorbidity primarily responsible for major lower-limb amputations, particularly for diabetic patients. Autologous cell therapy has been the focus of efforts over the past 20 years to create non-interventional therapeutic options for no-option CLTI to improve limb perfusion and wound healing. Among the different available techniques, peripheral blood mononuclear cells (PBMNC) appear to be the most promising autologous cell therapy due to physio-pathological considerations and clinical evidence, which will be discussed in this review. A meta-analysis of six clinical studies, including 256 diabetic patients treated with naive, fresh PBMNC produced via a selective filtration point-of-care device, was conducted. PBMNC was associated with a mean yearly amputation rate of 15.7%, a mean healing rate of 62%, and a time to healing of 208.6 ± 136.5 days. Moreover, an increase in TcPO2 and a reduction in pain were observed. All-cause mortality, with a mean rate of 22.2% and a yearly mortality rate of 18.8%, was reported. No serious adverse events were reported. Finally, some practical and financial considerations are provided, which point to the therapy's recommendation as the first line of treatment for this particular and crucial patient group.

The Use of Autologous Cell Therapy in Diabetic Patients with Chronic Limb-Threatening Ischemia

Autologous cell therapy (ACT) is primarily used in diabetic patients with chronic limb-threatening ischemia (CLTI) who are not candidates for standard revascularization. According to current research, this therapy has been shown in some studies to be effective in improving ischemia parameters, decreasing the major amputation rate, and in foot ulcer healing. This review critically evaluates the efficacy of ACT in patients with no-option CLTI, discusses the use of mononuclear and mesenchymal stem cells, and compares the route of delivery of ACT. In addition to ACT, we also describe the use of new revascularization strategies, e.g., nanodiscs, microbeads, and epigenetics, that could enhance the therapeutic effect. The main aim is to summarize new findings on subcellular and molecular levels with the clinical aspects of ACT.

One-Year Analysis of Autologous Peripheral Blood Mononuclear Cells as Adjuvant Therapy in Treatment of Diabetic Revascularizable Patients Affected by Chronic Limb-Threatening Ischemia: Real-World Data from Italian Registry ROTARI

Wounds in diabetic patients with peripheral arterial disease (PAD) may be poorly responsive to revascularization and conventional therapies. Background/Objective: This study's objective is to analyze the results of regenerative cell therapy with peripheral blood mononuclear cells (PBMNCs) as an adjuvant to revascularization. Methods: This study is based on 168 patients treated with endovascular revascularization below the knee plus three PBMNC implants. The follow-up included clinical outcomes at 1-2-3-6 and 12 months based on amputations, wound healing, pain, and TcPO2. Results: The results at 1 year for 122 cases showed a limb rescue rate of 94.26%, a complete wound healing in 65.59% of patients, and an improvement in the wound area, significant pain relief, and increased peripheral oxygenation. In total, 64.51% of patients completely healed at 6 months, compared to the longer wound healing time reported in the literature in the same cohort of patients, suggesting that PBMNCs have an adjuvant effect in wound healing after revascularization. Conclusions: PBMNC regenerative therapy is a safe and promising treatment for diabetic PAD. In line with previous experiences, this registry shows improved healing in diabetic patients with below-the-knee arteriopathy. The findings support the use of this cell therapy and advocate for further research.

Effectiveness of Stem Cell Therapy for Diabetic Foot Ulcers: A Systematic Review and GRADE Compliant Bootstrapped Meta-Analysis of Randomized Clinical Trials

Diabetic foot (DF) represents a severe complication of diabetes mellitus, imposing substantial psychological and economic burdens on affected individuals. This investigation sought to assess the therapeutic efficacy of stem cell interventions in the management of DF complications. A comprehensive systematic search across PubMed, Embase, CINAHL, Scopus, and the Cochrane library databases was conducted to identify pertinent studies for meta-analysis. Outcome measures encompassed ulcer or wound healing rates, amputation rates, angiogenesis, ankle-brachial index (ABI), and pain-free walking distance. Dichotomous outcomes were expressed as risk differences (RDs) with 95% confidence intervals (CIs), while continuous data were articulated as standardized mean differences (SMDs) with corresponding 95% CIs. Statistical analyses were executed using RevMan 5.3 and Open Meta, with bootstrapped meta-analysis conducted through OpenMEE software. A total of 20 studies, comprising 24 arms and involving 1304 participants, were incorporated into the meta-analysis. The findings revealed that stem cell therapy exhibited superior efficacy compared to conventional interventions in terms of ulcer or wound healing rate [RD = 0.36 (0.28, 0.43)], pain-free walking distance [SMD = 1.27 (0.89, 1.65)], ABI [SMD = 0.61 (0.33, 0.88)], and new vessel development [RD = 0.48 (0.23, 0.78)], while concurrently reducing the amputation rate significantly [RD = -0.19 (-0.25, -0.12)]. Furthermore, no statistically significant difference in adverse events was observed [RD -0.07 (-0.16, 0.02)]. The Grading of Recommendations, Assessment, Development, and Evaluation assessment indicated varying levels of evidence certainty, ranging from very low to moderate, for different outcomes. Bootstrapping analysis substantiated the precision of the results. The meta-analysis underscores the significant superiority of stem cell therapy over conventional approaches in treating DF complications. Future investigations should prioritize large-scale, randomized, double-blind, placebo-controlled, multicenter trials, incorporating rigorous long-term follow-up protocols. These studies are essential for elucidating the optimal cell types and therapeutic parameters that contribute to the most effective treatment strategies for DF management.

Current State and Future Perspective of Diabetic Wound Healing Treatment: Present Evidence from Clinical Trials

Diabetes is a chronic metabolic condition that is becoming more common and is characterised by sustained hyperglycaemia and long-term health effects. Diabetes-related wounds often heal slowly and are more susceptible to infection because of hyperglycaemia in the wound beds. The diabetic lesion becomes harder to heal after planktonic bacterial cells form biofilms. A potential approach is the creation of hydrogels with many functions. High priority is given to a variety of processes, such as antimicrobial, pro-angiogenesis, and general pro-healing. Diabetes problems include diabetic amputations or chronic wounds (DM). Chronic diabetes wounds that do not heal are often caused by low oxygen levels, increased reactive oxygen species, and impaired vascularization. Several types of hydrogels have been developed to get rid of contamination by pathogens; these hydrogels help to clean up the infection, reduce wound inflammation, and avoid necrosis. This review paper will focus on the most recent improvements and breakthroughs in antibacterial hydrogels for treating chronic wounds in people with diabetes. Prominent and significant side effects of diabetes mellitus include foot ulcers. Antioxidants, along with oxidative stress, are essential to promote the healing of diabetic wounds. Some of the problems that can come from a foot ulcer are neuropathic diabetes, ischemia, infection, inadequate glucose control, poor nutrition, also very high morbidity. Given the worrying rise in diabetes and, by extension, diabetic wounds, future treatments must focus on the rapid healing of diabetic wounds.

Cell Therapy of Severe Ischemia in People with Diabetic Foot Ulcers-Do We Have Enough Evidence?

This current opinion article critically evaluates the efficacy of autologous cell therapy (ACT) for chronic limb-threatening ischemia (CLTI), especially in people with diabetes who are not candidates for standard revascularization. This treatment approach has been used in 'no-option' CLTI in the last two decades and more than 1700 patients have received ACT worldwide. Here we analyze the level of published evidence of ACT as well as our experience with this treatment method. Many studies have shown that ACT is safe and an effective method for patients with the most severe lower limb ischemia. However, some trials did not show any benefit of ACT, and there is some heterogeneity in the types of injected cells, route of administration and assessed endpoints. Nevertheless, we believe that ACT plays an important role in a comprehensive treatment of patients with diabetic foot and severe ischemia.

Re-Epithelialization of Neuropathic Diabetic Foot Wounds with the Use of Cryopreserved Allografts of Human Epidermal Keratinocyte Cultures (Epifast)

The application of tissue-engineering technology to wound healing has become an option for the treatment of diabetic foot ulcers (DFU). A comparative, prospective study was conducted to assess the efficacy of a cryopreserved allograft of human epidermal keratinocytes (Epifast) to enhance wound healing in granulating DFU. Eighty patients were assigned to receive Epifast (n = 40) or Standard Care (SC) treatment (n = 40). The Epifast group displayed a shorter duration of the epithelialization phase (3.5 ± 4 vs. 6.4 ± 3.6 weeks, p < 0.05) and upon the entire wound healing process than the SC group (10 ± 5.7 vs. 14.5 ± 8.9 weeks, p < 0.05), reaching wound closure at 16 and 30 weeks, respectively. The Kaplan−Meier analysis revealed that Epifast group patients were 50% more likely than the SC to heal wounds faster (Cox-hazards ratio of 0.5, 95% CI = 0.3−0.8, p < 0.0001; Likelihood Ratio of 7.8. p < 0.05). Patients in the control group displayed a slower healing as the Saint Elian (SEWSS) severity grade increased (group differences of 0.6, 3.8, and 4.3 weeks for grades I, II, and III, respectively). DFW treated with Epifast displayed a shorter time to complete re-epithelialization than wounds treated with standard care.

Potential of stem cells for treating infected Diabetic Foot Wounds and Ulcers: a systematic review

Infected diabetic foot ulcers (iDFUs) cause great concern, as they generally heal poorly and are precursive of diabetic-related foot amputation and even death. Scientists have tested various techniques in attempts to ascertain the best treatment for iDFUs; however, the results have remained inconclusive. Stem cell therapy (SCT) appears to improve iDFU through its antimicrobial impacts, yet cogent information regarding the repair of iDFUs with SCT is lacking. Herein, published articles are evaluated to report coherent information about the antimicrobial effects of SCT on the repair of iDFUs in diabetic animals and humans. In this systematic review, we searched the Scopus, Medline, Google Scholar, and Web of Science databases for relevant full-text English language articles published from 2000 to 2022 that described stem cell antimicrobial treatments, infected diabetic wounds, or ulcers. Ultimately, six preclinical and five clinical studies pertaining to the effectiveness of SCT on healing infected diabetic wounds or ulcers were selected. Some of the human studies confirmed that SCT is a promising therapy for diabetic wounds and ulcers. Notably, more controlled studies performed on animal models revealed that stem cells combined with a biostimulator such as photobiomodulation decreased colony forming units and hastened healing in infected diabetic wounds. Moreover, stem cells alone had lower therapeutic impact than when combined with a biostimulant.

Effectiveness and safety of stem cell therapy for diabetic foot: a meta-analysis update

BACKGROUND

Diabetic foot (DF) is one of the most common and serious complications of diabetes mellitus (DM), which brings great psychological and economic pressure to patients. This study aimed to evaluate the efficacy of stem cells in the treatment of diabetic foot.

METHODS

All relevant studies in Cochrane, Embase, PubMed, Web of Science, China National Knowledge Infrastructure, and WanFang databases were systematically searched for meta-analysis. The outcomes consisted of ulcer or wound healing rate, amputation rate, new vessels, ankle-brachial index (ABI), transcutaneous oxygen pressure (TcPO2), pain-free walking distance, and rest pain score. Dichotomous outcomes were described as risk ratios (RR) with 95% confidence intervals (CIs), while continuous data were presented as standardized mean differences (SMDs) with 95% CIs. Statistical analysis was performed with RevMan 5.3 software.

RESULTS

A total of 14 studies with 683 participants were included in the meta-analysis. Meta-analysis showed that stem cell therapy was more effective than conventional therapy in terms of ulcer or wound healing rate [OR = 8.20 (5.33, 12.62)], improvement in lower extremity ischemia(new vessels) [OR = 16.48 (2.88, 94.18)], ABI [MD = 0.13 (0.04, 0.08)], TcO2[MD = 4.23 (1.82, 6.65)], pain-free walking distance [MD = 220.79 (82.10, 359.48)], and rest pain score [MD = - 1.94 (- 2.50, - 1.39)], while the amputation rate was significantly decreased [OR = 0.19 (0.10, 0.36)].

CONCLUSIONS

The meta-analysis of the current studies has shown that stem cells are significantly more effective than traditional methods in the treatment of diabetic foot and can improve the quality of life of patients after treatment. Future studies should conduct large-scale, randomized, double-blind, placebo-controlled, multicenter trials with high-quality long-term follow-up to demonstrate the most effective cell types and therapeutic parameters for the treatment of diabetic foot.

Stem Cell Therapy in Limb Ischemia: State-of-Art, Perspective, and Possible Impacts of Endometrial-Derived Stem Cells

As an evidence-based performance, the rising incidence of various ischemic disorders has been observed across many nations. As a result, there is a growing need for the development of more effective regenerative approaches that could serve as main therapeutic strategies for the treatment of these diseases. From a cellular perspective, promoted complex inflammatory mechanisms, after inhibition of organ blood flow, can lead to cell death in all tissue types. In this case, using the stem cell technology provides a safe and regenerative approach for ischemic tissue revascularization and functional cell formation. Limb ischemia (LI) is one of the most frequent ischemic disease types and has been shown to have a promising regenerative response through stem cell therapy based on several clinical trials. Bone marrow-derived mononuclear cells (BM-MNCs), peripheral blood CD34-positive mononuclear cells (CD34+ PB-MNCs), mesenchymal stem cells (MSCs), and endothelial stem/progenitor cells (ESPCs) are the main, well-examined stem cell types in these studies. Additionally, our investigations reveal that endometrial tissue can be considered a suitable candidate for isolating new safe, effective, and feasible multipotent stem cells for limb regeneration. In addition to other teams’ results, our in-depth studies on endometrial-derived stem cells (EnSCs) have shown that these cells have translational potential for limb ischemia treatment. The EnSCs are able to generate diverse types of cells which are essential for limb reconstruction, including endothelial cells, smooth muscle cells, muscle cells, and even peripheral nervous system populations. Hence, the main object of this review is to present stem cell technology and evaluate its method of regeneration in ischemic limb tissue.

Autologous Immune Cell-Based Regenerative Therapies to Treat Vasculogenic Erectile Dysfunction: Is the Immuno-Centric Revolution Ready for the Prime Time?

About 35% of patients affected by erectile dysfunction (ED) do not respond to oral phosphodiesterase-5 inhibitors (PDE5i) and more severe vasculogenic refractory ED affects diabetic patients. Innovative approaches, such as regenerative therapies, including stem cell therapy (SCT) and platelet-rich plasma (PRP), are currently under investigation. Recent data point out that the regenerative capacity of stem cells is strongly influenced by local immune responses, with macrophages playing a pivotal role in the injury response and as a coordinator of tissue regeneration, suggesting that control of the immune response could be an appealing approach in regenerative medicine. A new generation of autologous cell therapy based on immune cells instead of stem cells, which could change regenerative medicine for good, is discussed. Increasing safety and efficacy data are coming from clinical trials using peripheral blood mononuclear cells to treat no-option critical limb ischemia and diabetic foot. In this review, ongoing phase 1/phase 2 stem cell clinical trials are discussed. In addition, we examine the mechanism of action and rationale, as well as propose a new generation of regenerative therapies, evolving from typical stem cell or growth factor to immune cell-based medicine, based on autologous peripheral blood mononuclear cells (PBMNC) concentrates for the treatment of ED.

Pitavastatin-Incorporated Nanoparticles for Chronic Limb Threatening Ischemia: A Phase I/IIa Clinical Trial

AIM

To assess the results of a phase I/IIa open-label dose-escalation clinical trial of 5-day repeated intramuscular administration of pitavastatin-incorporated poly (lactic-co-glycolic acid) nanoparticles (NK-104-NP) in patients with chronic limb threatening ischemia (CLTI).

METHODS

NK-104-NP was formulated using an emulsion solvent diffusion method. NK-104-NP at four doses (nanoparticles containing 0.5, 1, 2, and 4 mg of pitavastatin calcium, n=4 patients per dose) was investigated in a dose-escalation manner and administered intramuscularly into the ischemic limbs of 16 patients with CLTI. The safety and therapeutic efficacy of treatment were investigated over a 26-week follow-up period.

RESULTS

No cardiovascular or other serious adverse events caused by NK-104-NP were detected during the follow-up period. Improvements in Fontaine and Rutherford classifications were noted in five patients (one, three, and one in the 1-, 2-, and 4-mg dose groups, respectively). Pharmacokinetic parameters including the maximum serum concentration and the area under the blood concentration-time curve increased with pitavastatin treatment in a dose-dependent manner. The area under the curve was slightly increased at day 5 compared with that at day 1 of treatment, although the difference was not statistically significant.

CONCLUSIONS

This is the first clinical trial of pitavastatin-incorporated nanoparticles in patients with CLTI. Intramuscular administration of NK-104-NP to the ischemic limbs of patients with CLTI was safe and well tolerated and resulted in improvements in limb function.

Comparison of Three Methods for Preparation of Autologous Cells for Use in Cell Therapy of Chronic Limb-Threatening Ischemia in People with Diabetes

Autologous cell therapy (ACT) is a new therapeutic approach for diabetic patients with no-option chronic limb-threatening ischemia (NO-CLTI). The aim of our study was to quantify cell populations of cell therapy products (CTPs) obtained by three different isolation methods and to correlate their numbers with changes in transcutaneous oxygen pressure (TcPO2). CTPs were separated either from stimulated peripheral blood (PB) (n = 11) or harvested from bone marrow (BM) processed either by Harvest SmartPReP2 (n = 50) or sedimented with succinate gelatin (n = 29). The clinical effect was evaluated by the change in TcPO2 after 1, 3 and 6 months. TcPO2 increased significantly in all three methods at each time point in comparison with baseline values (p < .01) with no significant difference among them. There was no correlation between the change in TcPO2 and the size of injected cell populations. We only observed a weak correlation between the number of injected white blood cells (WBC) and an increase in TcPO2 at 1 and 3 months. Our study showed that all three isolation methods of ACT were similarly relatively efficient in the treatment of NO-CLTI. We observed no correlation of TcPO2 increase with the number of injected monocytes, lymphocytes or CD34+. We observed a weak correlation between TcPO2 increase and the number of injected WBCs.

The peripheral blood mononuclear cells versus purified CD34+ cells transplantation in patients with angiitis-induced critical limb ischemia trial: 5-year outcomes and return to work analysis-a randomized single-blinded non-inferiority trial

Backgrounds

Patients with AICLI constitute a considerable proportion of NO-CLI patients and cannot be treated with surgical or endovascular treatment. Although cell therapy has shown satisfactory results in treating AICLI, research comparing the efficacy of treatment with the 2 kinds of cell products is rare. The aim of this study was to report the 5-year outcomes of a randomized single-blinded noninferiority trial (Number: NCT 02089828) on peripheral blood mononuclear cells (PBMNCs) and purified CD34⁺ cells (PCCs) transplantation for treating angiitis-induced critical limb ischemia (AICLI).

Methods

A randomized single-blinded non-inferiority trial (Number: NCT 02089828) was performed. Fifty patients were randomized 1:1 to the PBMNCs and PCCs groups. Efficacy outcomes, safety outcomes and patients’ work conditions were analyzed. The primary efficacy outcomes included major amputation and total amputation over 60 months.

Results

During the 60-month follow-up, 1 patient was lost to follow-up, 1 died, and 2 underwent major amputation. The major amputation-free survival rate (MAFS) was 92.0% (95% confidence interval [CI] 82.0%-100.0%) in the PBMNCs group and 91.7% (95% CI 81.3%-100.0%) in the PCCs group (P = 0.980). Compared with the PCCs group, the PBMNCs group had a significantly higher 5-year new lesion-free survival rate (100.0% vs. 83.3% [95% CI 69.7–99.7%], P = 0.039). All patients lost their ability to work before transplantation, and the 5-year cumulative return to work (RTW) rates were 88.0% in the PBMNCs group and 76.0% in the PCCs group (P = 0.085).

Conclusion

The long-term follow-up outcomes of this trial not only demonstrated similar efficacy and safety for the 2 types of autoimplants but also showed a satisfactory cumulative RTW rate in AICLI patients who underwent cell transplantation.

Trial registration: ClinicalTrials.gov, number NCT 02089828. Registered 14 March 2014, https://clinicaltrials.gov/ct2/show/record/NCT02089828.

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.

Comparison of the impact of autologous cell therapy and conservative standard treatment on tissue oxygen supply and course of the diabetic foot in patients with chronic limb-threatening ischemia: A randomized controlled trial

BACKGROUND

Autologous cell therapy (ACT) is a new treatment method for patients with diabetes and no-option chronic limb-threatening ischemia (NO-CLTI). We aimed to assess the impact of ACT on NO-CLTI in comparison with standard treatment (ST) in a randomized controlled trial.

METHODS

Diabetic patients with NO-CLTI were randomized to receive either ACT (n=21) or ST (n=19). After 12 weeks, those in the ST group, who did not improve were treated with ACT. The effect of ACT on ischemia and wound healing was assessed by changes in transcutaneous oxygen pressure (TcPO₂) and the number of healed patients at 12 weeks. Pain was evaluated by Visual Analogue Scale (VAS). Amputation rates and amputation-free survival (AFS) were assessed in both groups.

RESULTS

During the first 12 weeks, TcPO₂ increased in the ACT group from 20.8 ± 9.6 to 41.9 ± 18.3 mm Hg (p=0.005) whereas there was no change in the ST group (from 21.2 ± 11.4 to 23.9 ± 13.5 mm Hg). Difference in TcPO₂ in the ACT group compared to ST group was 21.1 mm Hg (p=0.034) after 12 weeks. In the period from week 12 to week 24, when ST group received ACT, the TcPO₂ in this group increased from 20.1 ± 13.9 to 41.9 ± 14.8 (p=0.005) while it did not change significantly in the ACT in this period. At 24 weeks, there was no significant difference in mean TcPO₂ between the two groups. Wound healing was greater at 12 weeks in the ACT group compared to the ST group (5/16 vs. 0/13, p=0.048). Pain measured using VAS was reduced in the ACT group after 12 weeks compared to the baseline, and the difference in scores was again significant (p<0.001), but not in the ST group. There was no difference in rates of major amputation and AFS between ACT and ST groups at 12 weeks.

CONCLUSIONS

This study has showed that ACT treatment in patients with no-option CLTI and diabetic foot significantly improved limb ischemia and wound healing after 12 weeks compared to conservative standard therapy. Larger randomized controlled trials are needed to study the benefits of ACT in patients with NO-CLTI and diabetic foot disease.

TRIAL REGISTRATION

The trial was registered in the National Board of Health (EudraCT 2016-001397-15).

Autologous Stem Cell Therapy for Chronic Lower Extremity Wounds: A Meta-Analysis of Randomized Controlled Trials

Lower extremity chronic wounds (LECWs) commonly occur in patients with diabetes mellitus (DM) and peripheral arterial disease (PAD). Autologous stem cell therapy (ASCT) has emerged as a promising alternative treatment for those who suffered from LECWs. The purpose of this study was to assess the effects of ASCT on LECWs. Two authors searched three core databases, and independently identified evidence according to predefined criteria. They also individually assessed the quality of the included randomized controlled trials (RCTs), and extracted data on complete healing rate, amputation rate, and outcomes regarding peripheral circulation. The extracted data were pooled using a random-effects model due to clinical heterogeneity among the included RCTs. A subgroup analysis was further performed according to etiology, source of stem cells, follow-up time, and cell markers. A total of 28 RCTs (n = 1096) were eligible for this study. The pooled results showed that patients receiving ASCT had significantly higher complete healing rates (risk ratio (RR) = 1.67, 95% confidence interval (CI) 1.28-2.19) as compared with those without ASCT. In the CD34+ subgroup, ASCT significantly led to a higher complete healing rate (RR = 2.70, 95% CI 1.50-4.86), but there was no significant difference in the CD34- subgroup. ASCT through intramuscular injection can significantly improve wound healing in patients with LECWs caused by either DM or critical limb ischemia. Lastly, CD34+ is an important cell marker for potential wound healing. However, more extensive scale and well-designed studies are necessary to explore the details of ASCT and chronic wound healing.

Intra-lesionally autologous stem cell application in diabetic foot/ulcer

The diabetic fot/ulcer is the cause of high morbidity and mortality in patients with diabetes mellitus (DM). Generally, medical treatment of diabetic foot/ulcer is ineffective and stem cell implantation is an important option in the treatment. Here, we present a 69 years old man admitted to hospital due to a 3 × 4 cm wound in the plantar surface of left foot. Autologous stem cells were applied intralesionally into diabetic ulcers. The lesion shrunken 50 % at the 16th week and there is a wound under the left foot at 32nd week. Intralesionally autologous stem cell application was useful and safe without adverse course in patients with diabetic foot/ulcer.

Autologous cell therapy in diabetes‑associated critical limb ischemia: From basic studies to clinical outcomes (Review)

Cell therapy is becoming an attractive alternative for the treatment of patients with no‑option critical limb ischemia (CLI). The main benefits of cell therapy are the induction of therapeutic angiogenesis and neovascularization that lead to an increase in blood flow in the ischemic limb and tissue regeneration in non‑healing cutaneous trophic lesions. In the present review, the current state of the art of strategies in the cell therapy field are summarized, focusing on intra‑operative autologous cell concentrates in diabetic patients with CLI, examining different sources of cell concentrates and their mechanisms of action. The present study underlined the detrimental effects of the diabetic condition on different sources of autologous cells used in cell therapy, and also in delaying wound healing capacity. Moreover, relevant clinical trials and critical issues arising from cell therapy trials are discussed. Finally, the new concept of cell therapy as an adjuvant therapy to increase wound healing in revascularized diabetic patients is introduced.

Autologous Peripheral Blood Mononuclear Cells for Limb Salvage in Diabetic Foot Patients with No-Option Critical Limb Ischemia

Peripheral blood mononuclear cells (PBMNCs) are reported to prevent major amputation and healing in no-option critical limb ischemia (NO-CLI). The aim of this study is to evaluate PBMNC treatment in comparison to standard treatment in NO-CLI patients with diabetic foot ulcers (DFUs). The study included 76 NO-CLI patients admitted to our centers because of CLI with DFUs. All patients were treated with the same standard care (control group), but 38 patients were also treated with autologous PBMNC implants. Major amputations, overall mortality, and number of healed patients were evaluated as the primary endpoint. Only 4 out 38 amputations (10.5%) were observed in the PBMNC group, while 15 out of 38 amputations (39.5%) were recorded in the control group (p = 0.0037). The Kaplan-Meier curves and the log-rank test results showed a significantly lower amputation rate in the PBMNCs group vs. the control group (p = 0.000). At two years follow-up, nearly 80% of the PBMNCs group was still alive vs. only 20% of the control group (p = 0.000). In the PBMNC group, 33 patients healed (86.6%) while only one patient healed in the control group (p = 0.000). PBMNCs showed a positive clinical outcome at two years follow-up in patients with DFUs and NO-CLI, significantly reducing the amputation rate and improving survival and wound healing. According to our study results, intramuscular and peri-lesional injection of autologous PBMNCs could prevent amputations in NO-CLI diabetic patients.

Three-year outcomes of peripheral blood mononuclear cells vs purified CD34+ cells in the treatment of angiitis-induced no-option critical limb ischemia and a cost-effectiveness assessment: A randomized single-blinded noninferiority trial

For patients with angiitis-induced critical limb ischemia (AICLI), cell transplantation, such as purified CD34+ cells (PCCs) and peripheral blood mononuclear cells (PBMNCs), is gradually being used as a promising treatment. This was the first randomized single-blinded noninferiority trial (number: NCT02089828) specifically designed to evaluate the therapeutic efficacies of the transplantation of PCCs vs those of PBMNCs for the treatment of AICLI. We aimed to compare the mid-term safety and efficacy between the two groups and determine their respective advantages. From April 2014 to September 2019, 50 patients with AICLI were equally allocated to the two groups, except for 1 lost patient, 1 amputee, and 1 patient who died of heart disease. The other 47 patients completed the 36-month follow-up. The endpoints were as follows: major amputation-free survival and total amputation-free survival at 6 months, which were 96.0% and 84.0% in the PBMNCs group and 96.0% and 72.0% in the PCCs group, respectively. These rates remained stable at 12, 24, and 36 months. The PCCs group had a significant higher probability of rest pain relief than the PBMNCs group, whereas earlier significant improvements in the Rutherford classification were observed in the PBMNCs group. Accordingly, PCCs would be preferred for patients with significant pain, whereas PBMNCs may be a good option for patients with two or more critically ischemic limbs. Concerning cost-effectiveness, PCCs are not more cost-effective than PBMNCs. These outcomes require verification from long-term trials involving larger numbers of patients.

Effect of recombinant equine interleukin-1β on function of equine endothelial colony-forming cells in vitro

OBJECTIVE

To investigate the effects of recombinant equine IL-1β on function of equine endothelial colony-forming cells (ECFCs) in vitro.

SAMPLE

ECFCs derived from peripheral blood samples of 3 healthy adult geldings.

PROCEDURES

Function testing was performed to assess in vitro wound healing, tubule formation, cell adhesion, and uptake of 1,1'-dioctadecyl-3,3,3',3' tetramethylindocarbocyanine perchlorate-labeled acetylated low-density lipoprotein (DiI-Ac-LDL) by cultured ECFCs. Cell proliferation was determined by 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay. Effects on function test results of different concentrations and exposure times of recombinant equine IL-1β were assessed.

RESULTS

Challenge of cultured ECFCs with IL-1β for 48 hours inhibited tubule formation. Continuous challenge (54 hours) with IL-1β in the wound healing assay reduced gap closure. The IL-1β exposure did not significantly affect ECFC adhesion, DiI-Ac-LDL uptake, or ECFC proliferation.

CONCLUSIONS AND CLINICAL RELEVANCE

These results suggested a role for IL-1β in the inhibition of ECFC function in vitro. Functional changes in ECFCs following challenge with IL-1β did not appear to be due to changes in cell proliferative capacity. These findings have implications for designing microenvironments for and optimizing therapeutic effects of ECFCs used to treat ischemic diseases in horses.

Autologous Bone-Marrow vs. Peripheral Blood Mononuclear Cells Therapy for Peripheral Artery Disease in Diabetic Patients

Diabetes mellitus (DM) remains one of the most important risk factors for peripheral artery disease (PAD), with approximately 20% of DM patients older than 40 years old are affected with PAD. The current standard management for severe PAD is endovascular intervention with or without surgical bypass. Unfortunately, up to 40% of patients are unable to undergo these revascularization therapies due to excessive surgical risk or adverse vascular side effects. Stem cell therapy has emerged as a novel therapeutic strategy for these ‘no-option’ patients. Several types of stem cells are utilized for PAD therapy, including bone marrow mononuclear cells (BMMNC) and peripheral blood mononuclear cells (PBMNC). Many studies have reported the safety of BMMNC and PBMNC, as well as its efficacy in reducing ischemic pain, ulcer size, pain-free walking distance, ankle-brachial index (ABI), and transcutaneous oxygen pressure (TcPO2). However, the capacity to establish the efficacy of reducing major amputation rates, amputation free survival, and all-cause mortality is limited, as shown by several randomized placebo-controlled trials. The present literature review will focus on comparing safety and efficacy between BMMNC and PBMNC as cell-based management in diabetic patients with PAD who are not suitable for revascularization therapy.

Current Status of Angiogenic Cell Therapy and Related Strategies Applied in Critical Limb Ischemia

Critical limb ischemia (CLI) constitutes the most severe form of peripheral arterial disease (PAD), it is characterized by progressive blockade of arterial vessels, commonly correlated to atherosclerosis. Currently, revascularization strategies (bypass grafting, angioplasty) remain the first option for CLI patients, although less than 45% of them are eligible for surgical intervention mainly due to associated comorbidities. Moreover, patients usually require amputation in the short-term. Angiogenic cell therapy has arisen as a promising alternative for these "no-option" patients, with many studies demonstrating the potential of stem cells to enhance revascularization by promoting vessel formation and blood flow recovery in ischemic tissues. Herein, we provide an overview of studies focused on the use of angiogenic cell therapies in CLI in the last years, from approaches testing different cell types in animal/pre-clinical models of CLI, to the clinical trials currently under evaluation. Furthermore, recent alternatives related to stem cell therapies such as the use of secretomes, exosomes, or even microRNA, will be also described.

Peripheral Arterial Disease in Persons with Diabetic Foot Ulceration: a Current Comprehensive Overview

In developed countries, the prevalence of persons with diabetes and peripheral arterial disease (PAD) is approximately 50%. The presence of PAD is associated with non-healing ulcers, major amputation, cardiovascular morbidity, and mortality. It is estimated that persons with diabetes, foot ulceration and PAD have 50% of 5-years mortality rate. Therefore, subjects with ischemic diabetic foot ulcers (DFUs) should be considered a special group of patients with specific clinical characteristics, general health status and prognosis. In persons with ischemic DFUs, an early diagnosis and treatment are mandatory to reduce the risk of worse outcomes such as major amputation. Revascularization of occluded lower extremity arteries is the main treatment to restore blood flow in the foot and promote wound healing. Nonetheless, there are several unmet needs in the management of diabetic subjects with PAD and foot ulceration as medical therapy, diagnostic criteria and indications for revascularization, revascularization strategy and technical approach as well as the management of no-option critical limb ischemia patients. It is a common opinion that there is an evolution of PAD features in diabetic persons, which seems to present a more aggressive pattern. This may be related to the frequent presence of concomitant comorbidities such as renal failure which could influence the characteristics of atherosclerotic plaques and their distribution. The aim of this review is to commence a complete overview and state of the art in the treatment of patients with diabetes, PAD, and foot ulceration and to describe the current challenges and future perspectives.

Randomized, Double-Blind, Placebo-Controlled Trial to Evaluate Safety and Therapeutic Efficacy of Angiogenesis Induced by Intraarterial Autologous Bone Marrow-Derived Stem Cells in Patients with Severe Peripheral Arterial Disease

PURPOSE

To evaluate safety and efficacy of angiogenesis induced by intraarterial autologous bone marrow-derived stem cell (BMSC) injection in patients with severe peripheral arterial disease (PAD).

MATERIALS AND METHODS

Eighty-one patients with severe PAD (77 men), including 56 with critical limb ischemia (CLI) and 25 with severe claudication, were randomized to receive sham injection (group A) or intraarterial BMSC injection at the site of occlusion (group B). Primary endpoints included improvement in ankle-brachial index (ABI) of > 0.1 and transcutaneous pressure of oxygen (TcPO₂) of > 15% at mid- and lower foot at 6 mo. Secondary endpoints included relief from rest pain, > 30% reduction in ulcer size, and reduction in major amputation in patients with CLI and > 50% improvement in pain-free walking distance in patients with severe claudication.

RESULTS

Technical success was achieved in all patients, without complications. At 6 mo, group B showed more improvements in ABI of > 0.1 (35 of 41 [85.37%] vs 13 of 40 [32.50%]; P < .0001) and TcPO₂ of > 15% at the midfoot (35 of 41 [85.37%] vs 17 of 40 [42.50%]; P = .0001] and lower foot (37 of 41 [90.24%] vs 19 of 40 [47.50%]; P < .0001). No patients with CLI underwent major amputation in group B, compared with 4 in group A (P = .0390). No significant difference was observed in relief from rest pain or > 30% reduction in ulcer size among patients with CLI or in > 50% improvement in pain-free walking distance among patients with severe claudication.

CONCLUSIONS

Intraarterial delivery of autologous BMSCs is safe and effective in the management of severe PAD.

Cell-Based Therapies for Chronic Wounds Tested in Clinical Studies: Review

INTRODUCTION

Transplantation of the keratinocytes, fibroblasts, bone marrow, and adipose tissue-derived mesenchymal stem cells may improve chronic wound healing by delivery of different cytokines, chemokines, and growth factors, which play an essential role in wound healing. The purposes of this review were to check which cell lines are potentially beneficial in enhancement of wound healing and to describe the safety and efficacy of cell therapies in the clinical treatment of chronic wounds, as well as to summarize the pertinent literature and research progress in this field.

METHODS

PubMed search engine and ClinicalTrials.gov were used to analyze the available data on cell therapies applied in treatment of chronic wound. The analysis included 51 articles, assessing the use of keratinocytes (10), fibroblasts (7), keratinocytes and fibroblasts (10), bone marrow-derived cells (20), and adipose tissue cells (4). Studies on the cell-based products that are currently available on the market (Dermagraft, EpiDex, Apligraf, and HP802-247) were also included, with majority of reports found on fibroblasts and keratinocytes studies.

RESULTS

Cell-based therapies have a great potential to improve wound healing without major surgical procedures and donor-site morbidity. There is, however, a lack of guidelines on how the age of the patients, the general health conditions, and the coexistence of different diseases may affect the success of these therapies. Further studies are needed to determine the fate of transplanted cells and the number of cells required to obtain optimal effects and outcomes.

CONCLUSIONS

Despite many promising clinical trials on application of various stem cell-based therapies for treatment of chronic wounds, there is still a need for multicenter comparative studies assessing the dose response and the cell source response on the efficacy of chronic wound healing.

Rejuvenated Circulating Endothelial Progenitor Cells and Nitric Oxide in Premenopausal Women with Hyperhomocysteinemia

Hyperhomocysteinemia (HHcy) induced endothelial dysfunction is associated with disturbance in circulating endothelial progenitor cells (EPCs). Nevertheless, whether this unfavorable effect of HHcy on circulating EPCs also exists in premenopausal women is still unknown. Therefore, this leaves an area for the investigation of the difference on the number and activity of circulating EPCs in premenopausal women with hyperhomocysteinemia and its underlying mechanism. The number of circulating EPCs was measured by fluorescence-activated cell sorter analysis, as well as DiI-acLDL and lectin fluorescent staining. The migration and proliferation of circulating were evaluated by the Transwell chamber assay and MTT. Additionally, the endothelial function and levels of nitric oxide (NO), VEGF, and GM-CSF in plasma and culture medium were determined. The number or activity of circulating EPCs and flow-mediated dilatation (FMD) in premenopausal women with or without HHcy were higher than those in postmenopausal women. However, no significant effect of HHcy on the number or activity of circulating EPCs in premenopausal women was observed. A similar alteration in NO level between the four groups was observed. There was a correlation between FMD and the number or activity of EPCs, as well as NO level in plasma or secretion by EPCs. For the first time, our findings illuminated the quantitive or qualitative alterations of circulating EPCs and endothelial function in premenopausal patients with HHcy are preserved, which was associated with retained NO production. The recuperated endothelial repair capacity is possibly the potential mechanism interpreting cardiovascular protection in premenopausal women with HHcy.

Autologous peripheral blood-derived stem cells transplantation for treatment of no-option angiitis-induced critical limb ischemia: 10-year management experience

Background

Previous studies have demonstrated that no-option angiitis-induced critical limb ischemia (NO-AICLI) could be significantly improved by transplantation of peripheral blood-derived stem cells (PBDSCs). Additionally, a randomized controlled trial (RCT) recently conducted by us suggested that peripheral blood-derived purified CD34+ cells (PCCs) were not inferior to non-purified peripheral blood mononuclear cells (PBMNCs) at limb salvage in treatment of NO-AICLI. However, most of these clinical trials whether RCT or single-arm studies were characterized with a small sample size and absence of long-term outcomes.

Methods

To analyze long-term clinical outcomes of PBDSCs transplantation for NO-AICLI, we reviewed clinical data of patients with NO-AICLI receiving PBDSCs transplantation at our center during the past decade. Meanwhile, we first compared the long-term safety and efficacy of intramuscular transplantation of PCCs versus PBMNCs in a sizable number of patients with NO-AICLI.

Results

From May 2009 to December 2019, a total of 160 patients with NO-AICLI patients were treated by PBDSCs transplantation (82 with PCCs, 78 with PBMNCs) at our center. Baseline characteristics between two groups were similar. Up to June 2020, the mean follow-up period was 46.6 ± 35.3 months. No critical adverse events were observed in either group. There was one death during the follow-up period. A total of eight major amputations occurred. The cumulative major amputation-free survival (MAFS) rate at 5 years after PBDSCs transplantation was 94.4%, without difference between two groups (P = .855). Wound healing, rest pain, pain-free walking time, ankle-brachial index, transcutaneous oxygen pressure, and quality of life (QoL) also significantly improved after PBDSCs transplantation.

Conclusions

Autologous PBDSCs intramuscular transplantation could significantly decrease the major amputation rates and improve the QoL in patients with NO-AICLI. Long-term observation of a large sample of patients confirmed that the clinical benefits of PBDSCs transplantation were durable, without difference between the PCCs and PBMNCs groups.

Medical adjunctive therapy for patients with chronic limb-threatening ischemia: a systematic review

INTRODUCTION

The aim of this article is to systematically review the literature on medical adjunctive therapy for patients with chronic limb-threatening ischemia (CLTI).

EVIDENCE ACQUISITION

MEDLINE, Embase, and Cochrane Database of Systematic Reviews were searched for studies published between January 1st, 2009, and June 1st, 2019. Articles that studied medical treatment of CLTI patients and reported clinical outcomes were eligible. Main exclusion criteria were case reports <20 patients, incorrect publication type, and CLTI caused by Buerger disease. The primary end point was major amputation (above the ankle) in studies with a follow-up of ≥6 months. Secondary end points were other clinical end points such as death and wound healing. Study quality was assessed according to the Downs and Black checklist.

EVIDENCE SYNTHESIS

Included were 42 articles: four focused on antiplatelet therapy, five on antihypertensive medication, 6 on lipid-lowering therapy, 16 on stem cell therapy, three on growth factors, five on prostanoids, and one study each on cilostazol, glucose-lowering therapy, spinal cord stimulation, sulodexide, and hemodilution. Calcium channel blockers, iloprost, cilostazol, and hemodilution showed significant improvement of limb salvage, but data are limited. Stem cell therapy showed no significant improvement of limb salvage but could potentially improve wound healing. Antiplatelets, antihypertensives, and statins showed significantly lower cardiovascular events rates but not evident lower major amputation rates. The quality of the studies was fair to good.

CONCLUSIONS

Certain medical therapies serve to improve limb salvage next to revascularization in CLTI patients, whereas others are important in secondary prevention. Because high quality evidence is limited, further research is needed.

Critical limb ischemia: Current and novel therapeutic strategies

Critical limb ischemia (CLI) is the advanced stage of peripheral artery disease spectrum and is defined by limb pain or impending limb loss because of compromised blood flow to the affected extremity. Current conventional therapies for CLI include amputation, bypass surgery, endovascular therapy, and pharmacological approaches. Although these conventional therapeutic strategies still remain as the mainstay of treatments for CLI, novel and promising therapeutic approaches such as proangiogenic gene/protein therapies and stem cell-based therapies have emerged to overcome, at least partially, the limitations and disadvantages of current conventional therapeutic approaches. Such novel CLI treatment options may become even more effective when other complementary approaches such as utilizing proper bioscaffolds are used to increase the survival and engraftment of delivered genes and stem cells. Therefore, herein, we address the benefits and disadvantages of current therapeutic strategies for CLI treatment and summarize the novel and promising therapeutic approaches for CLI treatment. Our analyses also suggest that these novel CLI therapeutic strategies show considerable advantages to be used when current conventional methods have failed for CLI treatment.

Impact of severe diabetic kidney disease on the clinical outcome of autologous cell therapy in people with diabetes and critical limb ischaemia

AIM

To assess the impact of autologous cell therapy on critical limb ischaemia in people with diabetes and diabetic kidney disease.

METHODS

A total of 59 people with diabetes (type 1 or type 2) and critical limb ischaemia, persisting after standard revascularization, were treated with cell therapy in our foot clinic over 7 years; this group comprised 17 people with and 42 without severe diabetic kidney disease. The control group had the same inclusion criteria, but was treated conservatively and comprised 21 people with and 23 without severe diabetic kidney disease. Severe diabetic kidney disease was defined as chronic kidney disease stages 4-5 (GFR <30 ml/min/1.73 m²). Death and amputation-free survival were assessed during the 18-month follow-up; changes in transcutaneous oxygen pressure were evaluated at 6 and 12 months after cell therapy.

RESULTS

Transcutaneous oxygen pressure increased significantly in both groups receiving cell therapy compared to baseline (both P<0.01); no significant change in either of the control groups was observed. The cell therapy severe diabetic kidney disease group had a significantly longer amputation-free survival time compared to the severe diabetic kidney disease control group (hazard ratio 0.36, 95% CI 0.14-0.91; P=0.042); there was no difference in the non-severe diabetic kidney disease groups. The severe diabetic kidney disease control group had a tendency to have higher mortality (hazard ratio 2.82, 95% CI 0.81-9.80; P=0.062) than the non-severe diabetic kidney disease control group, but there was no difference between the severe diabetic kidney disease and non-severe diabetic kidney disease cell therapy groups.

CONCLUSIONS

The present study shows that autologous cell therapy in people with severe diabetic kidney disease significantly improved critical limb ischaemia and lengthened amputation-free survival in comparison with conservative treatment; however, the treatment did not influence overall survival.

Clinical and (31)P magnetic resonance spectroscopy characterization of patients with critical limb ischemia before and after autologous cell therapy

Autologous cell therapy (ACT) is a new treatment method for diabetic patients with critical limb ischemia (CLI) not eligible for standard revascularization. After intramuscular injection of bone marrow-derived mononuclear cells local arteriogenesis in the ischemic tissue occurs. Studies assessing visualization of this therapeutic vasculogenesis after ACT by novel imaging techniques are lacking. The aim of our study was to assess the effect of ACT on possible metabolic changes and perfusion of critically ischemic limbs using (31)P magnetic resonance spectroscopy ( (31)P MRS) and its possible correlation with changes of transcutaneous oxygen pressure (TcPO(2)). Twenty-one patients with diabetes and no-option CLI treated by ACT in our foot clinic over 8 years were included in the study. TcPO(2) as well as rest (phosphocreatine, adenosine triphosphate and inorganic phosphate) and dynamic (mitochondrial capacity and phosphocreatine recovery time) (31)P-MRS parameters were evaluated at baseline and 3 months after cell treatment. TcPO(2) increased significantly after 3 months compared with baseline (from 22.4±8.2 to 37.6±13.3 mm Hg, p=0.0002). Rest and dynamic (31)P MRS parameters were not significantly different after ACT in comparison with baseline values. Our study showed a significant increase of TcPO(2) on the dorsum of the foot after ACT. We did not observe any changes of rest or dynamic (31)P MRS parameters in the area of the proximal calf where the cell suspension has been injected into.

Acellular and cellular approaches to improve diabetic wound healing

Chronic diabetic wounds represent a huge socioeconomic burden for both affected individuals and the entire healthcare system. Although the number of available treatment options as well as our understanding of wound healing mechanisms associated with diabetes has vastly improved over the past decades, there still remains a great need for additional therapeutic options. Tissue engineering and regenerative medicine approaches provide great advantages over conventional treatment options, which are mainly aimed at wound closure rather than addressing the underlying pathophysiology of diabetic wounds. Recent advances in biomaterials and stem cell research presented in this review provide novel ways to tackle different molecular and cellular culprits responsible for chronic and nonhealing wounds by delivering therapeutic agents in direct or indirect ways. Careful integration of different approaches presented in the current article could lead to the development of new therapeutic platforms that can address multiple pathophysiologic abnormalities and facilitate wound healing in patients with diabetes.

Skin tissue regeneration for burn injury

The skin is the largest organ of the body, which meets the environment most directly. Thus, the skin is vulnerable to various damages, particularly burn injury. Skin wound healing is a serious interaction between cell types, cytokines, mediators, the neurovascular system, and matrix remodeling. Tissue regeneration technology remarkably enhances skin repair via re-epidermalization, epidermal-stromal cell interactions, angiogenesis, and inhabitation of hypertrophic scars and keloids. The success rates of skin healing for burn injuries have significantly increased with the use of various skin substitutes. In this review, we discuss skin replacement with cells, growth factors, scaffolds, or cell-seeded scaffolds for skin tissue reconstruction and also compare the high efficacy and cost-effectiveness of each therapy. We describe the essentials, achievements, and challenges of cell-based therapy in reducing scar formation and improving burn injury treatment.

Predictors of responders to mononuclear stem cell-based therapeutic angiogenesis for no-option critical limb ischemia

Background

Although the mononuclear cell (MNC) transplantation could theoretically induce therapeutic angiogenesis in the patients with no-option critical limb ischemia (NO-CLI), the clinical responses to this approach are inconsistent among different clinical trials. The purpose of this study was to identify the prognostic factors of responders and develop a predictive nomogram to guide patient selection.

Methods

We retrospectively reviewed a consecutive NO-CLI cohort who received peripheral blood-derived transplantation in our center. The patients who survived and achieved complete remission of CLI at 6 months post-transplantation were defined as responders. Logistic regression models were used to screen and identify the prognostic factors based on which predictive nomogram was developed. A receiver operating characteristic (ROC) curve and a calibration curve were drawn to determine the discrimination level and predictive accuracy.

Results

The study ultimately enrolled 103 patients, including 58 responders and 45 non-responders. Based on the multivariate regression analysis, age ≥ 50 years (odds ratio [OR] 0.201, P = 0.004), blood fibrinogen > 4 g/L (OR 0.176, P = 0.003), arterial occlusion above the knee/elbow (OR 0.232, P = 0.010), the transcutaneous pressure of oxygen (TcPO₂) (OR 1.062, P = 0.006), and the Log total transplanted CD34⁺ cell count (OR 3.506, P = 0.046) were identified as independent prognostic factors of the responders in the nomogram. An area under the ROC curve of 0.851 indicated good discrimination, and the calibration curve of the predicted probability showed optimal agreement with that of the observed probability.

Conclusions

Age, blood fibrinogen, arterial occlusion level, TcPO₂, and the total transplanted CD34⁺ cell count were independent prognostic factors of the responders. A nomogram with high discrimination and accuracy was developed to provide individualized predictions.

Trail registration

ChiCTR, ChiCTR1800019401. Registered 9 November 2018—Retrospectively registered

Electronic supplementary material

The online version of this article (10.1186/s13287-018-1117-5) contains supplementary material, which is available to authorized users.

Transplantation of human mobilized mononuclear cells improved diabetic neuropathy

Rodent stem cells demonstrated regenerative effects in diabetic neuropathy via improvement in nerve perfusion. As a pre-clinical step, we explored if human mobilized mononuclear cells (hMNC) would have the same effects in rats. hMNC were injected into Rt. hind-limb muscles of streptozotocin-induced diabetic nude rats, and the grafts were monitored using with MRI. After 4 weeks, the effects were compared with those in the vehicle-injected Lt. hind limbs. Nerve conduction, muscle perfusion and gene expression of sciatic nerves were assessed. Induction of diabetes decreased nerve function and expression of Mpz and Met in the sciatic nerves, which are related with myelination. hMNC injection significantly improved the amplitude of compound muscle action potentials along with muscle perfusion and sciatic nerve Mpz expression. On MRI, hypointense signals were observed for 4 weeks at the graft site, but their correlation with the presence of hMNC was detectable for only 1 week. To evaluate paracrine effects of hMNC, IMS32 cells were tested with hepatocyte growth factor (HGF), which had been reported as a myelination-related factor from stem cells. We could observe that HGF enhanced Mpz expression in the IMS32 cells. Because hMNC secreted HGF, IMS32 cells were co-cultured with hMNC, and the expression of Mpz increased along with morphologic maturation. The hMNC-induced Mpz expression was abrogated by treatment of anti-HGF. These results suggest that hMNC could improve diabetic neuropathy, possibly through enhancement of myelination as well as perfusion. According to in vitro studies, HGF was involved in the hMNC-induced myelination activity, at least in part.

Purified CD34+ cells versus peripheral blood mononuclear cells in the treatment of angiitis-induced no-option critical limb ischaemia: 12-Month results of a prospective randomised single-blinded non-inferiority trial

BACKGROUND

Peripheral blood mononuclear cells (PBMNCs) and purified CD34+ cells (PCCs) are increasingly being used at treating no-option critical limb ischaemia (NO-CLI). We aimed to compare the efficacies and uncover the advantages associated with each treatment approach.

METHODS

A randomised single-blinded non-inferiority trial (Number: NCT 02089828) was performed. NO-CLI patients were 1:1 randomised to the PBMNCs and PCCs groups, and compared in relation to safety and efficacy outcomes. The primary efficacy outcomes included major amputation and total amputation over 12 months. The major amputation-free survival (MAFS) and total amputation-free survival (TAFS) rates were calculated.

FINDINGS

Fifty patients (25 per group, 47 with thromboangiitis obliterans and 3 with other angiitis) were enrolled, with a median follow-up period of 24.5 months (interquartile range: 17-34 months). One patient in the PCCs group was lost at 2 months and one major amputation occurred in the PBMNCs group at 3 months post-transplantation. The total amputation rates at 6 months post-transplantation were 28.0% in the PCCs group and 16.0% in the PBMNCs group (p = 0.343), and remained unchanged at 12 months. The groups did not differ regarding the MAFS and TAFS (Breslow-Wilcoxon test: p = 0.3014 and p = 0.3414). The PCCs group had a significantly higher probability of rest pain relief than the PBMNCs group (Breslow-Wilcoxon test: p = 0.0454).

INTERPRETATION

PCCs was not inferior to PBMNCs at limb salvage in the treatment of angiitis-induced NO-CLI and appeared to induce earlier ischaemia relief. Each cell type had specific advantages. These outcomes require verification from longer-term trials involving larger numbers of patients. FUND: Training program for outstanding academic leaders of Shanghai health and family planning system (Hundred Talent Program，Grant No. 2018BR40); China National Natural Science Funds (Grant No. 30801122); The excellent core member training programme at Zhongshan Hospital, Fudan University, China (Grant No. 2015ZSYXGG02); and Zhongshan Funds for the Institute of Vascular Surgery, Fudan University, China.

CLINICAL TRIAL REGISTRATION

This study is registered with ClinicalTrials.gov (NCT 02089828).

Autologous cells derived from different sources and administered using different regimens for 'no-option' critical lower limb ischaemia patients

BACKGROUND

Revascularisation is the gold standard therapy for patients with critical limb ischaemia (CLI). In over 30% of patients who are not suitable for or have failed previous revascularisation therapy (the 'no-option' CLI patients), limb amputation is eventually unavoidable. Preliminary studies have reported encouraging outcomes with autologous cell-based therapy for the treatment of CLI in these 'no-option' patients. However, studies comparing the angiogenic potency and clinical effects of autologous cells derived from different sources have yielded limited data. Data regarding cell doses and routes of administration are also limited.

OBJECTIVES

To compare the efficacy and safety of autologous cells derived from different sources, prepared using different protocols, administered at different doses, and delivered via different routes for the treatment of 'no-option' CLI patients.

SEARCH METHODS

The Cochrane Vascular Information Specialist (CIS) searched the Cochrane Vascular Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE Ovid, Embase Ovid, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Allied and Complementary Medicine Database (AMED), and trials registries (16 May 2018). Review authors searched PubMed until February 2017.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) involving 'no-option' CLI patients comparing a particular source or regimen of autologous cell-based therapy against another source or regimen of autologous cell-based therapy.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed the eligibility and methodological quality of the trials. We extracted outcome data from each trial and pooled them for meta-analysis. We calculated effect estimates using a risk ratio (RR) with 95% confidence interval (CI), or a mean difference (MD) with 95% CI.

MAIN RESULTS

We included seven RCTs with a total of 359 participants. These studies compared bone marrow-mononuclear cells (BM-MNCs) versus mobilised peripheral blood stem cells (mPBSCs), BM-MNCs versus bone marrow-mesenchymal stem cells (BM-MSCs), high cell dose versus low cell dose, and intramuscular (IM) versus intra-arterial (IA) routes of cell implantation. We identified no other comparisons in these studies. We considered most studies to be at low risk of bias in random sequence generation, incomplete outcome data, and selective outcome reporting; at high risk of bias in blinding of patients and personnel; and at unclear risk of bias in allocation concealment and blinding of outcome assessors. The quality of evidence was most often low to very low, with risk of bias, imprecision, and indirectness of outcomes the major downgrading factors.Three RCTs (100 participants) reported a total of nine deaths during the study follow-up period. These studies did not report deaths according to treatment group.Results show no clear difference in amputation rates between IM and IA routes (RR 0.80, 95% CI 0.54 to 1.18; three RCTs, 95 participants; low-quality evidence). Single-study data show no clear difference in amputation rates between BM-MNC- and mPBSC-treated groups (RR 1.54, 95% CI 0.45 to 5.24; 150 participants; low-quality evidence) and between high and low cell dose (RR 3.21, 95% CI 0.87 to 11.90; 16 participants; very low-quality evidence). The study comparing BM-MNCs versus BM-MSCs reported no amputations.Single-study data with low-quality evidence show similar numbers of participants with healing ulcers between BM-MNCs and mPBSCs (RR 0.89, 95% CI 0.44 to 1.83; 49 participants) and between IM and IA routes (RR 1.13, 95% CI 0.73 to 1.76; 41 participants). In contrast, more participants appeared to have healing ulcers in the BM-MSC group than in the BM-MNC group (RR 2.00, 95% CI 1.02 to 3.92; one RCT, 22 participants; moderate-quality evidence). Researchers comparing high versus low cell doses did not report ulcer healing.Single-study data show similar numbers of participants with reduction in rest pain between BM-MNCs and mPBSCs (RR 0.99, 95% CI 0.93 to 1.06; 104 participants; moderate-quality evidence) and between IM and IA routes (RR 1.22, 95% CI 0.91 to 1.64; 32 participants; low-quality evidence). One study reported no clear difference in rest pain scores between BM-MNC and BM-MSC (MD 0.00, 95% CI -0.61 to 0.61; 37 participants; moderate-quality evidence). Trials comparing high versus low cell doses did not report rest pain.Single-study data show no clear difference in the number of participants with increased ankle-brachial index (ABI; increase of > 0.1 from pretreatment), between BM-MNCs and mPBSCs (RR 1.00, 95% CI 0.71 to 1.40; 104 participants; moderate-quality evidence), and between IM and IA routes (RR 0.93, 95% CI 0.43 to 2.00; 35 participants; very low-quality evidence). In contrast, ABI scores appeared higher in BM-MSC versus BM-MNC groups (MD 0.05, 95% CI 0.01 to 0.09; one RCT, 37 participants; low-quality evidence). ABI was not reported in the high versus low cell dose comparison.Similar numbers of participants had improved transcutaneous oxygen tension (TcO₂) with IM versus IA routes (RR 1.22, 95% CI 0.86 to 1.72; two RCTs, 62 participants; very low-quality evidence). Single-study data with low-quality evidence show a higher TcO₂ reading in BM-MSC versus BM-MNC groups (MD 8.00, 95% CI 3.46 to 12.54; 37 participants) and in mPBSC- versus BM-MNC-treated groups (MD 1.70, 95% CI 0.41 to 2.99; 150 participants). TcO₂ was not reported in the high versus low cell dose comparison.Study authors reported no significant short-term adverse effects attributed to autologous cell implantation.

AUTHORS' CONCLUSIONS

Mostly low- and very low-quality evidence suggests no clear differences between different stem cell sources and different treatment regimens of autologous cell implantation for outcomes such as all-cause mortality, amputation rate, ulcer healing, and rest pain for 'no-option' CLI patients. Pooled analyses did not show a clear difference in clinical outcomes whether cells were administered via IM or IA routes. High-quality evidence is lacking; therefore the efficacy and long-term safety of autologous cells derived from different sources, prepared using different protocols, administered at different doses, and delivered via different routes for the treatment of 'no-option' CLI patients, remain to be confirmed.Future RCTs with larger numbers of participants are needed to determine the efficacy of cell-based therapy for CLI patients, along with the optimal cell source, phenotype, dose, and route of implantation. Longer follow-up is needed to confirm the durability of angiogenic potential and the long-term safety of cell-based therapy.

Perfusion Scintigraphy in the Assessment of Autologous Cell Therapy in Diabetic Patients With Critical Limb Ischemia

Perfusion scintigraphy with technetium-99-methoxy-isobutyl-isonitrile (99mTc-MIBI) is often used for assessing myocardial function but the number of studies concerning lower limb perfusion is limited. The aim of our study was to assess whether 99mTc-MIBI was an eligible method for evaluation of the effect of cell therapy on critical limb ischemia (CLI) in diabetic patients. 99mTc-MIBI of calf muscles was performed before and 3 months after autologous cell therapy (ACT) in 24 diabetic patients with CLI. Scintigraphic parameters such as rest count and exercising count after a stress test were defined. These parameters and their ratios were compared between treated and untreated (control) limbs and with changes in transcutaneous oxygen pressure (TcPO2) that served as a reference method. The effect of ACT was confirmed by a significant increase in TcPO2 values (p˂0.001) at 3 months after ACT. We did not observe any significant changes of scintigraphic parameters both at rest and after stress 3 months after ACT, there were no differences between treated and control limbs and no association with TcPO2 changes. Results of our study showed no significant contribution of 99mTc-MIBI of calf muscles to the assessment of ACT in diabetic patients with CLI over a 3-month follow-up period.

Peripheral Blood Mononuclear Cells Therapy for Treatment of Lower Limb Ischemia in Diabetic Patients: A Single-Center Experience

BACKGROUND

The aim of this study is to analyze the effects of peripheral blood mononuclear cells (PBMNCs) therapy in diabetic patients with critical limb ischemia (CLI), with particular regard to its application, as adjuvant therapy in patients underwent endovascular revascularization.

METHODS

Fifty diabetic patients affected by CLI were enrolled. All patients underwent PBMNCs therapy. Thirty-two patients underwent PBMNCs therapy associated with endovascular revascularization (adjuvant therapy group). In 18 patients, who were considered nonrevascularizable or underwent unsuccessful revascularization, regenerative therapy with PBMNCs was performed as the therapeutic choice (PBMNCs therapy group).

RESULTS

The median follow-up period was 10 months. The baseline and end point results in adjuvant group were as follows. The mean transcutaneous partial pressure of oxygen (TcPO₂) improved from 25 ± 9.2 mmHg to 45.6 ± 19.1 mmHg (P < 0.001), and visual analogue scale (VAS) score means decreased from 8.6 ± 2.1 to 3.8 ± 3.5 (P = 0.001). In PBMNCs therapy group, the mean TcPO₂ improved from 16.2 ± 7.2 mmHg to 23.5 ± 8.4 mmHg (P < 0.001), and VAS score means decreased from 9 ± 1.1 to 4.1 ± 3.3 (P = 0.001). Major amputation was observed in 3 cases (9.4%), both in adjuvant therapy group and in PBMNCs therapy one (16.7%) (P = 0.6).

CONCLUSIONS

The role of cellular therapy with PBMNCs is decisive in the patients that are not susceptible to revascularization. In diabetic patients with CLI and healing resistant ulcers, the adjuvant PBMNCs therapy could represent a valid therapeutic option.

Stem cell therapy for diabetic foot ulcers: a review of preclinical and clinical research

BACKGROUND

Diabetic foot ulcer (DFU) is a severe complication of diabetes, preceding most diabetes-related amputations. DFUs require over US$9 billion for yearly treatment and are now a global public health issue. DFU occurs in the setting of ischemia, infection, neuropathy, and metabolic disorders that result in poor wound healing and poor treatment options. Recently, stem cell therapy has emerged as a new interventional strategy to treat DFU and appears to be safe and effective in both preclinical and clinical trials. However, variability in the stem cell type and origin, route and protocol for administration, and concomitant use of angioplasty confound easy interpretation and generalization of the results.

METHODS

The PubMed, Google Scholar, and EMBASE databases were searched and 89 preclinical and clinical studies were selected for analysis.

RESULTS

There was divergence between preclinical and clinical studies regarding stem cell type, origin, and delivery techniques. There was heterogeneous preclinical and clinical study design and few randomized clinical trials. Granulocyte-colony stimulating factor was employed in some studies but with differing protocols. Concomitant performance of angioplasty with stem cell therapy showed increased efficiency compared to either therapy alone.

CONCLUSIONS

Stem cell therapy is an effective treatment for diabetic foot ulcers and is currently used as an alternative to amputation for some patients without other options for revascularization. Concordance between preclinical and clinical studies may help design future randomized clinical trials.

Autologous Stem Cell Therapy in Critical Limb Ischemia: A Meta-Analysis of Randomized Controlled Trials

Objective

Critical limb ischemia (CLI) is the most dangerous stage of peripheral artery disease (PAD). Many basic researches and clinical treatment had been focused on stem cell transplantation for CLI. This systematic review was performed to review evidence for safety and efficacy of autologous stem cell therapy in CLI.

Methods

A systematic literature search was performed in the SinoMed, PubMed, Embase, ClinicalTrials.gov, and Cochrane Controlled Trials Register databases from building database to January 2018.

Results

Meta-analysis showed that cell therapy significantly increased the probability of ulcer healing (RR = 1.73, 95% CI = 1.45–2.06), angiogenesis (RR = 5.91, 95% CI = 2.49–14.02), and reduced the amputation rates (RR = 0.59, 95% CI = 0.46–0.76). Ankle-brachial index (ABI) (MD = 0.13, 95% CI = 0.11–0.15), TcO₂ (MD = 12.22, 95% CI = 5.03–19.41), and pain-free walking distance (MD = 144.84, 95% CI = 53.03–236.66) were significantly better in the cell therapy group than in the control group (P < 0.01).

Conclusions

The results of this meta-analysis indicate that autologous stem cell therapy is safe and effective in CLI. However, higher quality and larger RCTs are required for further investigation to support clinical application of stem cell transplantation.

Efficiency of stem cell based therapy in the treatment of diabetic foot ulcer: a meta-analysis

Diabetic foot ulcer is a chronic, refractory, frequent complication in diabetic patient. Its treatment often requires multidisciplinary joint efforts, diverse strategies have been adopted to address this annoying issue, including stem cell-based therapy/acellular dermal matrix/negative pressure wound therapy etc. However, consensus has not been reached. To assess the current evidence regarding the efficiency and potential advantages of stem cell-based therapy compared with conventional standard treatment and/or placebo in the treatment of diabetic foot ulcer. A comprehensive search in PubMed, EmBase, Cochrane Central and Web of Science databases was conducted during December 2016 and a systematic review and meta-analysis of all relevant studies were performed. A total of 7 studies that involved 224 diabetic foot patients, classified as Wagner grades 1-5, were analyzed. The pooled results confirmed the benefits of using the stem cell treatment. Partial and/or complete healing were significantly higher in the stem cell group compared with the control group (77.4% vs. 31.9%; RR: 2.22; 95% CI, 1.65-2.98). Subgroup analysis on ABI and TCP02 also confirmed the results. The present meta-analysis indicates that stem cell-based therapy can enhance the healing of diabetic foot ulcers and is associated with lesser pain, lower amputation rate and improved prognosis compared with normal treatment. Well-designed randomized controlled trials are required in the future in order to confirm and update these findings.

Adjuvant Biological Therapies in Chronic Leg Ulcers

Current biological treatments for non-healing wounds aim to address the common deviations in healing mechanisms, mainly inflammation, inadequate angiogenesis and reduced synthesis of extracellular matrix. In this context, regenerative medicine strategies, i.e., platelet rich plasmas and mesenchymal stromal cell products, may form part of adjuvant interventions in an integral patient management. We synthesized the clinical experience on ulcer management using these two categories of biological adjuvants. The results of ten controlled trials that are included in this systematic review favor the use of mesenchymal stromal cell based-adjuvants for impaired wound healing, but the number and quality of studies is moderate-low and are complicated by the diversity of biological products. Regarding platelet-derived products, 18 controlled studies investigated their efficacy in chronic wounds in the lower limb, but the heterogeneity of products and protocols hinders clinically meaningful quantitative synthesis. Most patients were diabetic, emphasizing an unmet medical need in this condition. Overall, there is not sufficient evidence to inform routine care, and further clinical research is necessary to realize the full potential of adjuvant regenerative medicine strategies in the management of chronic leg ulcers.

Stem cell-based peripheral vascular regeneration

Chronic critical limb ischemia (CLI) represents an end-stage manifestation of peripheral arterial disease (PAD). CLI patients are at very high risk of amputation and cardiovascular complications, leading to severe morbidity and mortality. Because many patients with CLI are ineligible for conventional revascularization procedures, it is urgently needed to explore alternative strategies to improve blood supply in the ischemic tissue. Although researchers initially focused on gene/protein therapy using proangiogenic growth factors/cytokines, recent discovery of somatic stem/progenitor cells including bone marrow (BM)-derived endothelial progenitor cells (EPCs) and mesenchymal stem cells (MSCs) has drastically developed the field of therapeutic angiogenesis for CLI. Overall, early phase clinical trials demonstrated that stem/progenitor cell therapies may be safe, feasible and potentially effective. However, only few late-phase clinical trials have been conducted. This review provides an overview of the preclinical and clinical reports to demonstrate the usefulness and the current limitations of the cell-based therapies.