Abstract 18814: Autologous CD133+ Immunoselected Cells for the Treatment of "no-option" Critical Limb Ischemia: A Pilot Monocentric Study

Background: critical limb ischemia (CLI) is characterized by chronic ischemic rest pain, ulcers or gangren. CLI results in major amputation in about 50% of patients. Recently, it has been shown that bone marrow-derived (BM) CD34+/CD133+ circulating cells promote new vessel growth in experimental models of CLI. Accordingly, we investigated the feasibility and safety of local intramuscular administration of autologous immunoselected CD133+ (AI-CD133+) cells in “no-option” patients. Methods: the protocol was approved by the ethical committee of our hospital and 10 “no-option” patients suffering CLI were enrolled. BM-derived mononuclear cells were mobilized by G-CSF administration and collected by leukapheresis. CD133+ cells were selected with Clini-MACS (Miltenyi Biotec). AI-CD133+ cells were administered intramuscularly by direct injection. FACS analysis and Hill assay (CFU-Hill colonies) were performed both before and after G-CSF administration. Clinical examination, pain assessment, Ankle Brachial Index (ABI) and transcutaneous oxygen tension (TcPO2) measurements were performed before the treatment and 3, 6 and 12 months thereafter. At the same time points, patients underwent Contrast Enhanced UltraSound (CEUS) to assess muscle perfusion. Results: mobilization of CD34+/CD133+ cells was successful in 8 out of 10 patients. Of relevance, 6 out of 8 treated patients showed relevant clinical improvements. In particular, the treatment drastically ameliorated local pain and favored the healing of the ulcers (figure). The 2 non-responders, both diabetics, underwent major amputation. An overall increase in ABI rate was documented by CEUS (ABI at 12 months increased from 91,45 to 136,82; p<0.05). TcPO2 increased by 45.5±34.1% after 1 year (p<0.05). The number of CFU-Hill colonies was significantly lower (p<0.05) in CLI patients compared with healthy donors; after G-CSF stimulation, the number of CFU colonies significantly increased, except in those patients who did not respond to the treatment. Conclusions: our results demonstrate the feasibility and safety of G-CSF mobilized AI-CD133+ cell injection in end stage CLI patients. Clinical and instrumental data suggest a dramatic effect of CD133+ treatment, except in diabetic patients.