Infusion of autologous-peripheral blood mononuclear cells: a new approach for limb salvage in patients with diabetes

Alba Di Pardo*, Enrico Cappello*, Giuseppe Pepe, Federico Marracino, Vincenzo Carrieri, Vittorio Maglione, and Francesco Pompeo

Unit of Vascular and Endovascular Surgery- Division of Regenerative Medicine for Vascular and Neurovascular diseases, IRCCS Neuromed, Pozzilli, Italy 

* The two authors contributed equally to this work

Diabetes is the most common metabolic disorder clinically expressed by chronic hyperglycemia that has been extensively reported as linked to several vascular and neurological complications that significantly impair patient quality of life. The disease has a severe impact on the health systems worldwide and its incidence and prevalence is progressively increasing around the world, with approximately 642 million people predicted to be affected by the year 2040.  
Foot ulcer is a major complication of poorly controlled diabetes and probably the major component of the diabetic foot syndrome (DFS), which represents a very common precursor event prior of lower extremity amputation and the first cause of hospitalization in diabetic patients. Due to the multifactorial pathogenic profile, care of the diabetic foot involves a focused interdisciplinary approach and often fails to sufficiently respond to conventional treatments such as drug therapy and vascular surgery. Beside the huge emotional and social burden that the DFS may cause to patients, the resulting physical impairment represents a significant cause of health care costs. Thus, there is an urgent need for new care strategies to deal with this problem.
Over the last decade, research has mainly focused its efforts on developing cell-based therapies as a potential alternative and more effective therapeutic interventions for skin regeneration and ulcer repair. 
Emerging evidence indicates that circulating mononuclear cells isolated from peripheral blood (PBMNC) have remarkable regenerative expansion capacities and are able to speed up tissue repair by promoting neoangiogenesis, collagen deposition and re-epithelization. 
The aim of this study is to demonstrate the therapeutic efficacy of autologous-PBMNC (A-PBMNC) infusion in diabetic patients with unresponsive skin ulcers and to investigate the underlying molecular mechanisms. 
A-PBMNC were isolated from fresh venous blood sample through a new selective filtration and the cell concentration system - WB Pall Celeris System (CE marked under the 93/42/EEC Medical Devices Directive) -. After filtration, cells were infused back through multiple local, intralesional and perilesional intramuscular injections and along the relevant axis. Molecular profile and biological responses to A-PBMNC infusion were investigated by histological examination of the incisional biopsy of the ulcers.
Infusion of A-PBMNC leads to a clinically significant reduction in pain at rest and markedly accelerates the healing of the wound and the regeneration of damaged tissue.
Favourable clinical outcomes were integrated by histological evaluation clearly showing that A-PBMNC infusion significantly increases angiogenic cytokine production in the dermis, modulates local inflammatory response and promotes formation of new vessels, collagen deposition and re-epithelization of ulcers. 
A-PBMNC-based therapy is an innovative and promising approach for the wound healing, regeneration of damaged tissues and tissue repair in the DFS. Taking into account the prompt and long-term effects together with a favourable safety profile, it is plausible to believe that this strategy may significantly decrease the risk of amputation in diabetic patients with critical ischemia of the limb. From our perspective, all these properties make this procedure a key player in the future of the healthcare in such as chronic and worldwide disease