A Multicenter Prospective Interventional Trial of Therapeutic Angiogenesis Using Bone Marrow-Derived Mononuclear Cell Implantation for Patients With Critical Limb-Threatening Ischemia Caused by Thromboangiitis Obliterans

BACKGROUND

Thromboangiitis obliterans (TAO) can lead to the development of critical limb-threatening ischemia (CLTI). Despite conventional treatments, such as smoking cessation or revascularization, young patients (<50 years) still require limb amputation. Therapeutic angiogenesis using bone marrow-derived mononuclear cell (BM-MNC) implantation has been tested and shown to have reasonable efficacy in CLTI. In this multicenter prospective clinical trial, we evaluated the safety and efficacy of BM-MNC implantation in CLTI patients with TAO.Methods and Results: We enrolled 22 CLTI patients with skin perfusion pressure (SPP) <30 mmHg. The primary endpoint of this trial is the recovery of SPP in the treated limb after a 180-day follow-up period. Secondary endpoints include the pain scale score and transcutaneous oxygen pressure (TcPO2). One patient dropped out during follow-up, leaving 21 patients (mean age 48 years, 90.5% male, Fontaine Class IV) for analysis. BM-MNC implantation caused no serious adverse events and increased SPP by 1.5-fold compared with baseline. Surprisingly, this effect was sustained over the longer term at 180 days. Secondary endpoints also supported the efficacy of this novel therapy in relieving pain and increasing TcPO2. Major amputation-free and overall survival probabilities at 3 years among all enrolled patients were high (95.5% and 89.5%, respectively).

CONCLUSIONS

BM-MNC implantation showed safety and significant efficacy in CLTI patients with TAO.

Current State and Issues of Regenerative Medicine for Rheumatic Diseases

The prognosis of rheumatic diseases is generally better than that of malignant diseases. However, some cases with poor prognoses resist conventional therapies and cause irreversible functional and organ damage. In recent years, there has been much research on regenerative medicine, which uses stem cells to restore the function of missing or dysfunctional tissues and organs. The development of regenerative medicine is also being attempted in rheumatic diseases. In diseases such as systemic sclerosis (SSc), systemic lupus erythematosus (SLE), and rheumatoid arthritis, hematopoietic stem cell transplantation has been attempted to correct and reconstruct abnormalities in the immune system. Mesenchymal stem cells (MSCs) have also been tried for the treatment of refractory skin ulcers in SSc using the ability of MSCs to differentiate into vascular endothelial cells and for the treatment of systemic lupus erythematosus SLE using the immunosuppressive effect of MSCs. CD34-positive endothelial progenitor cells (EPCs), which are found in the mononuclear cell fraction of bone marrow and peripheral blood, can differentiate into vascular endothelial cells at the site of ischemia. Therefore, EPCs have been used in research on vascular regeneration therapy for patients with severe lower limb ischemia caused by rheumatic diseases such as SSc. Since the first report of induced pluripotent stem cells (iPSCs) in 2007, research on regenerative medicine using iPSCs has been actively conducted, and their application to rheumatic diseases is expected. However, there are many safety issues and bioethical issues involved in regenerative medicine research, and it is essential to resolve these issues for practical application and spread of regenerative medicine in the future. The environment surrounding regenerative medicine research is changing drastically, and the required expertise is becoming higher. This paper outlines the current status and challenges of regenerative medicine in rheumatic diseases.

Human mesenchymal stem cells for the management of systemic sclerosis. Systematic review

INTRODUCTION

Sistemic Sclerosis (SSc) is a heterogeneous autoimmune disease with a high rate of progression and therapeutic failure, and treatment is a challenge, new therapeutic proposals being needed, being mesenchymal stem cells (MSCs) considered as alternative therapy for SSc for its immunomodulatory capacity. We evaluated the efficacy and safety of human MSC (hMSC) in patients with SSc through a systematic literature review (SLR).

METHODS

SLR (PRISMA guideline) on MEDLINE/OVID, LILACS, EMBASE, and Cochrane/OVID bases (until July 2020, without limits). All types of clinical studies were considered: patients ≥18 years old with SSc and treatment with hMSC.

EXCLUSION CRITERIA

animal models, autologous/allogenic hematopoietic stem cell transplants, narrative reviews, letters to the editor. MeSH and "Key word" terms were used. The level of evidence and the quality rating were rated [Joanna Briggs Institute (JBI) lists]. Registration in PROSPERO repository (ID CRD42020185245) The Synthesis Without Meta-analysis (SWiM) guideline was followed.

RESULTS

We initially identified 508 articles, of which 11 were finally included (8 case series and 3 case reports). The 11 articles included 101 patients (85 female, age range 18-75 years). The level of evidence was mostly 4 (JBI); the quality of evidence was met (≥50% of JBI items). SWiM showed that vascular skin involvement (digital ulcers, necrosis, and gangrene) and associated pain were the predominant outcomes, while improvements were found in almost all cases. One patient died in the first month, and the frequency of complications was low. Expanded hMSCs were used in 24 patients and other cell sources in the remaining patients.

CONCLUSION

There is too little reported data to reach definite conclusions about the use of hMSC in SSc. Further studies with better epidemiological designs are needed to evaluate the benefit of hMSCs in SSc patients.

Therapeutic Angiogenesis Using Bone Marrow-Derived Mononuclear Cell Implantation for Patients With Critical Limb-Threatening Ischemia Caused by Thromboangiitis Obliterans - Study Protocol for a Multicenter Prospective Interventional Trial

Background: Patients with thromboangiitis obliterans (TAO) can develop critical limb-threatening ischemia (CLTI) and require limb amputation. Smoking cessation and exercise therapy are recommended as standard treatments, and revascularization by bypass surgery or endovascular therapy (EVT) is required for patients with CLTI. However, there are many cases in which revascularization is difficult because of vascular characteristics, and the patency rate after revascularization remains unsatisfactory. Therapeutic angiogenesis using bone marrow-derived mononuclear cell (BM-MNC) implantation is used clinically, with many trials demonstrating long-term efficacy and safety of the technique in patients with CLTI, especially that caused by TAO. To expand the use of BM-MNCs implantation in clinical practice, further evidence is required in patients with CLTI caused by TAO.

Methods and Results: This trial is a multicenter, prospective, non-randomized interventional trial of an Advanced Medicine B treatment approach. We aim to enroll 25 patients aged 20–80 years with Fontaine classification Stage III or IV, who will undergo BM-MNC implantation. The primary endpoint is the improvement in skin perfusion pressure of the target limb 180 days after BM-MNC implantation, whereas secondary endpoints are improvements in rest pain or ulcer size. We will also investigate rates of major or minor amputation, survival, and adverse events during follow-up.

Conclusions: BM-MNC implantation is expected to be an efficacious and feasible treatment for patients with CLTI caused by TAO.

Impact of Therapeutic Angiogenesis Using Autologous Bone Marrow-derived Mononuclear Cell Implantation in Patients with No-option Critical Limb Ischemia

Recently, the limb salvage rate of patients with critical limb ischemia (CLI) has been improved due to the development of revascularization and wound care treatment. However, many patients with CLI are refractory to standard treatments, including revascularization such as endovascular treatment or surgical bypass. Establishment of a new cell therapy is required to improve the limb salvage rate and prognosis in patients with CLI. In 1997, endothelial progenitor cells were found to be derived from the bone marrow to circulate as CD34 surface antigen positive cells in peripheral blood and to affect therapeutic angiogenesis in ischemic tissues. Later, therapeutic angiogenesis using autologous bone marrow-derived mononuclear cell (BM-MNC) implantation was performed for patients with no-option CLI in clinical practice. Several reports showed the safety and efficacy of the BM-MNC implantation in patients with CLI caused by arteriosclerosis obliterans, thromboangiitis obliterans (TAO), and collagen diseases. In particular, in patients with CLI caused by TAO, limb salvage rate was significantly improved compared with standard treatments. The BM-MNC implantation may be feasible and safe in patients with no-option CLI. Here, we review the efficacy of BM-MNC implantation in no-option CLI, with a focus on therapeutic angiogenesis.