Cell Therapy of Vascular and Neuropathic Complications of Diabetes: Can We Avoid Limb Amputation?

Globally, a leg is amputated approximately every 30 seconds, with an estimated 85 percent of these amputations being attributed to complications arising from diabetic foot ulcers (DFU), as stated by the American Diabetes Association. Peripheral arterial disease (PAD) is a risk factor resulting in DFU and can, either independently or in conjunction with diabetes, lead to recurring, slow-healing ulcers and amputations. According to guidelines amputation is the recommended treatment for patients with no-option critical ischemia of the limb (CTLI). In this article we propose cell therapy as an alternative strategy for those patients. We also suggest the optimal time-frame for an effective therapy, such as implanting autologous mononuclear cells (MNCs), autologous and allogeneic mesenchymal stromal cells (MSC) as these treatments induce neuropathy relief, regeneration of the blood vessels and tissues, with accelerated ulcer healing, with no serious side effects, proving that advanced therapy medicinal product (ATMPs) application is safe and effective and, hence, can significantly prevent limb amputation.

Efficacy and safety of intramuscular administration of allogeneic adipose tissue derived and expanded mesenchymal stromal cells in diabetic patients with critical limb ischemia with no possibility of revascularization: study protocol for a randomized controlled double-blind phase II clinical trial (The NOMA Trial)

Background

Chronic lower limb ischemia develops earlier and more frequently in patients with type 2 diabetes mellitus. Diabetes remains the main cause of lower-extremity non-traumatic amputations. Current medical treatment, based on antiplatelet therapy and statins, has demonstrated deficient improvement of the disease. In recent years, research has shown that it is possible to improve tissue perfusion through therapeutic angiogenesis. Both in animal models and humans, it has been shown that cell therapy can induce therapeutic angiogenesis, making mesenchymal stromal cell-based therapy one of the most promising therapeutic alternatives. The aim of this study is to evaluate the feasibility, safety, and efficacy of cell therapy based on mesenchymal stromal cells derived from adipose tissue intramuscular administration to patients with type 2 diabetes mellitus with critical limb ischemia and without possibility of revascularization.

Methods

A multicenter, randomized double-blind, placebo-controlled trial has been designed. Ninety eligible patients will be randomly assigned at a ratio 1:1:1 to one of the following: control group (n = 30), low-cell dose treatment group (n = 30), and high-cell dose treatment group (n = 30). Treatment will be administered in a single-dose way and patients will be followed for 12 months. Primary outcome (safety) will be evaluated by measuring the rate of adverse events within the study period. Secondary outcomes (efficacy) will be measured by assessing clinical, analytical, and imaging-test parameters. Tertiary outcome (quality of life) will be evaluated with SF-12 and VascuQol-6 scales.

Discussion

Chronic lower limb ischemia has limited therapeutic options and constitutes a public health problem in both developed and underdeveloped countries. Given that the current treatment is not established in daily clinical practice, it is essential to provide evidence-based data that allow taking a step forward in its clinical development. Also, the multidisciplinary coordination exercise needed to develop this clinical trial protocol will undoubtfully be useful to conduct academic clinical trials in the field of cell therapy in the near future.

Trial registration

ClinicalTrials.govNCT04466007. Registered on January 07, 2020. All items from the World Health Organization Trial Registration Data Set are included within the body of the protocol.

Adipose-derived mesenchymal stromal cells for the treatment of patients with severe SARS-CoV-2 pneumonia requiring mechanical ventilation. A proof of concept study

BACKGROUND

Identification of effective treatments in severe cases of COVID-19 requiring mechanical ventilation represents an unmet medical need. Our aim was to determine whether the administration of adipose-tissue derived mesenchymal stromal cells (AT-MSC) is safe and potentially useful in these patients.

METHODS

Thirteen COVID-19 adult patients under invasive mechanical ventilation who had received previous antiviral and/or anti-inflammatory treatments (including steroids, lopinavir/ritonavir, hydroxychloroquine and/or tocilizumab, among others) were treated with allogeneic AT-MSC. Ten patients received two doses, with the second dose administered a median of 3 days (interquartile range-IQR- 1 day) after the first one. Two patients received a single dose and another patient received 3 doses. Median number of cells per dose was 0.98 × 10⁶ (IQR 0.50 × 10⁶) AT-MSC/kg of recipient's body weight. Potential adverse effects related to cell infusion and clinical outcome were assessed. Additional parameters analyzed included changes in imaging, analytical and inflammatory parameters.

FINDINGS

First dose of AT-MSC was administered at a median of 7 days (IQR 12 days) after mechanical ventilation. No adverse events were related to cell therapy. With a median follow-up of 16 days (IQR 9 days) after the first dose, clinical improvement was observed in nine patients (70%). Seven patients were extubated and discharged from ICU while four patients remained intubated (two with an improvement in their ventilatory and radiological parameters and two in stable condition). Two patients died (one due to massive gastrointestinal bleeding unrelated to MSC therapy). Treatment with AT-MSC was followed by a decrease in inflammatory parameters (reduction in C-reactive protein, IL-6, ferritin, LDH and d-dimer) as well as an increase in lymphocytes, particularly in those patients with clinical improvement.

INTERPRETATION

Treatment with intravenous administration of AT-MSC in 13 severe COVID-19 pneumonia under mechanical ventilation in a small case series did not induce significant adverse events and was followed by clinical and biological improvement in most subjects.

FUNDING

None.