Results of a prospective observational study of autologous peripheral blood mononuclear cell therapy for no-option critical limb-threatening ischemia and severe diabetic foot ulcers

Cell therapy with autologous peripheral blood mononuclear cells (PB-MNCs) may help restore limb perfusion in patients with diabetes mellitus and critical limb-threatening ischemia (CLTI) deemed not eligible for revascularization procedures and consequently at risk for major amputation (no-option). Fundamental is to establish its clinical value and to identify candidates with a greater benefit over time. Assessing the frequency of PB circulating angiogenic cells and extracellular vesicles (EVs) may help in guiding candidate selection

The management of the infected diabetic foot

Diabetes is a chronic disease with a worldwide increasing trend. Foot complications, closely related to neuropathy and obstructive peripheral vascular disease, are responsible for more than 1 million of leg amputations every year. Foot infection can dramatically increase the risk of amputation. Although many ulcer classification systems have been proposed to stratify the severity of the infectious process, the definition of a specific therapeutic approach still remains an unsolved problem. A Diabetic Foot Triage and an Integrated Surgical Protocol are proposed to identify a diagnostic flowchart and a step-by-step surgical protocol that can be applied in the treatment of diabetic foot infection. Considering the rapid climbing of multidrug resistant strains it is very important to rationalize the use of antibiotics utilizing them only for the treatment of true infected ulcers. PAD is widely considered the most important factor conditioning the outcome of a diabetic foot ulcer. Currently no randomized control trials are reported in the international literature directly comparing open versus endovascular revascularisation in diabetic patients with CLI. Insufficient data are available to demonstrate whether open bypass surgery or endovascular interventions are more effective in these patients. A decisional flow chart in choosing the best revascularization strategy in diabetic patients with CLI is proposed. Goals and technical aspects of emergency and elective surgical procedures in diabetic foot are analysed to evaluate critical aspects and to suggest proper surgical choices

Additional file 1 of Results of a prospective observational study of autologous peripheral blood mononuclear cell therapy for no-option critical limb-threatening ischemia and severe diabetic foot ulcers

Additional file 1: Figure S1 Panel A-B. Representative case of gangrene of the big toe. Panel C. PB-MNCs injection procedure was performed along the relevant axis below the knee, below the ankle, and closed to the wound area, at intervals of 1–2 cm and to a mean depth of 1.5–2 cm, using a 21G needle.Panel D. Patient submitted to big toe necrosectomy with bone exposure and dressing with Bioinductive Dermal Substitute based on Hyaluronic Acid. Figure S2 Representative dot plots for the gating strategy to detect the relative frequency (expressed as % of cells positive for the selected surface antigens and their combination) of the following PB-MNCs populations, as determined by multicolor flow cytometry. For rare events (CD34+ and CD34+CXCR4+ cells), the large dot option, by FlowJo software, was used. FSC: forward scatter, SSC: side scatter. Figure S3 Representative images of two clinical cases. Panel A. Representative pictures of a clinical case of PB-MNCs therapy and right Chopart Amputation. From left to right: (i) before PB-MNCs therapy; (ii) at the time of the 1st treatment; (iii) at the 2nd treatment; (iv) at the 3rd treatment; (v) ulcer healing; (vi) definitive orthosis employing Below the Knee rigid casting with semi-rigid sole with high energy release to allow correct residual walking capacity. Panel B. Forefoot-mid foot gangrene in severe CLTI with no distal vessels run-off submitted to PB-MNC therapy. (i) Dorsal and (ii) plantar aspect of the foot; (iii) the aspect of the foot with secondary bone coverage and new dermal tissues coming from dermal substitute HA-based dressing. (iv) Dorsal and (v) plantar aspect of the foot at the indicated time after treatment. (vi) Correct orthesis for transmetatarsal amputation: custom-made shoes with lateral and medial reinforcement, biomechanics rigid rocker bottom sole, and fitting multilayer insole. Figure S4 Probability of ulcer healing without a major amputation during the 1st year after treatment in the study population stratified by TcPO2 at the last treatment (panel A); during the whole follow-up period in the study population stratified by TcPO2 at the last treatment (panel B). Patients who died or drop out were not counted as “at-risk” (censored subjects). Figure S5 Relative abundance of CD34+ subpopulations during PB-MNCs therapy stratified by ulcer healing without a major amputation after 1 year. Panel A. CD34+. Panel B. CD34+CXCR4+ HSPCs. The grey box represents patients with healing and the white box represents patients without healing at 1-year follow-up. No statistical differences were observed. Table S1 Perfusion and cellular characterization at enrollement, stratifying study population according to ulcer healing without a major amputation at 1 year. Table S2 Clinical outcomes occurred during follow-up, stratifying the study population according to TcPO2 levels after the last PB-MNCs treatment (< 40 mmHg; ≥ 40 mmHg)