Systematic review and meta-analysis of the effect of bone marrow-derived cell therapies on hind limb perfusion.

Preclinical and clinical studies on the administration of bone marrow-derived cells to restore perfusion show conflicting results. We conducted a systematic review and meta-analysis on preclinical studies to assess the efficacy of bone marrow-derived cells in the hind limb ischemia model and identify possible determinants of therapeutic efficacy. In vivo animal studies were identified using a systematic search in PubMed and EMBASE on 10 January 2022. 85 studies were included for systematic review and meta-analysis. Study characteristics and outcome data on relative perfusion were extracted. The pooled mean difference was estimated using a random effects model. Risk of bias was assessed for all included studies. We found a significant increase in perfusion in the affected limb after administration of bone marrow-derived cells compared to that in the control groups. However, there was a high heterogeneity between studies, which could not be explained. There was a high degree of incomplete reporting across studies. We therefore conclude that the current quality of preclinical research is insufficient (low certainty level as per GRADE assessment) to identify specific factors that might improve human clinical trials.

Human Bone Marrow Mononuclear Cells Do Not Improve Limb Perfusion in the Hindlimb Ischemia Model.

Effective treatments for chronic limb-threatening ischemia are lacking. (Pre)clinical studies on administration of bone marrow (BM) mononuclear cells (MNCs) and BM-derived mesenchymal stromal cells (MSCs) have shown variable results and no studies have directly compared administration of human BM MNCs and BM MSCs in in vivo models. We studied the effect of intramuscular administration of human BM-derived MNCs and MSCs on limb perfusion in the murine hindlimb ischemia (HLI) model. Human BM MNCs and MSCs were obtained from healthy consenting donors. Both cell types were cryopreserved before use. Twenty-four hours after induction of HLI, nude NMRI mice were randomized to receive intramuscular administration of human BM MNCs (n = 13), or BM MSCs (n = 14), or vehicle control (n = 19) in various doses. Limb perfusion was measured using laser Doppler imaging on day 0, 1, 4, 7, 10, and 14. Intramuscular injection of human BM MNCs did not improve limb perfusion as compared with vehicle over the 2 weeks after cell administration (P = 0.88, mean relative perfusion for vehicle 0.56 ± 0.04 and 0.53 ± 0.04 for BM MNCs at day 14). Administration of human BM MSCs significantly improved limb perfusion as compared with both BM MNCs and vehicle (P ≤ 0.001, mean relative perfusion at day 14 0.79 ± 0.06). Our data suggest that BM MNCs are less suitable than BM MSCs for cell-based therapy that aims to restore perfusion.