Relationship between cell number and clinical outcomes of autologous bone-marrow mononuclear cell implantation in critical limb ischemia

Cell therapy using intramuscular injections of autologous bone-marrow mononuclear cells (BM-MNCs) improves clinical symptoms and can prevent limb amputation in atherosclerotic peripheral arterial disease (PAD) patients with critical limb ischemia (CLI). The purpose of this study was to evaluate the effects of the number of implanted BM-MNCs on clinical outcomes in atherosclerotic PAD patients with CLI who underwent cell therapy. This study was a retrospective observational study with median follow-up period of 13.5 years (range, 6.8-15.5 years) from BM-MNC implantation procedure. The mean number of implanted cells was 1.2 ± 0.7 × 109 per limb. There was no significant difference in number of BM-MNCs implanted between the no major amputation group and major amputation group (1.1 ± 0.7 × 109 vs. 1.5 ± 0.8 × 109 per limb, P = 0.138). There was also no significant difference in number of BM-MNCs implanted between the no death group and death group (1.5 ± 0.9 × 109 vs. 1.8 ± 0.8 × 109 per patient, P = 0.404). Differences in the number of BM-MNCs (mean number, 1.2 ± 0.7 × 109 per limb) for cell therapy did not alter the major amputation-free survival rate or mortality rate in atherosclerotic PAD patients with CLI. A large number of BM-MNCs will not improve limb salvage outcome or mortality.