High Variability of Mesenchymal Stem Cells Obtained via Bone Marrow Aspirate Concentrate Compared With Traditional Bone Marrow Aspiration Technique

Background: Bone marrow aspirate (BMA) is a common source for harvesting mesenchymal stem cells (MSCs), other progenitor cells, and associated cytokines and growth factors to be used in the biologic treatment of various orthopaedic pathologies. The aspirate is commonly centrifuged into a concentrated volume that can be immediately administered to a patient using commercially available kits. However, the handling and efficacy of BMA concentrate (BMAC) are still controversial. Purpose: To characterize BMA versus BMAC for MSC quantity, potency, and cytokine profile. Study Design: Controlled laboratory study. Methods: From 8 participants (age, 17-68 years), 30 mL of bone marrow was aspirated by a single surgeon from either the proximal humerus or distal femur and was separated into 2 equal samples. One sample was kept as BMA, and the other half was centrifuged into BMAC. The 2 samples then underwent flow cytometry for detection of MSCs, cell analysis for colony-forming units (CFUs), and cytokine profiling. A 2-tailed t test was used to detect differences between MSCs, CFUs, and cytokine density concentrations between BMA and BMAC. Results: The average concentration of MSCs in both BMA and BMAC was 0.001%. Average MSC events detected by flow cytometry were significantly higher in BMA versus BMAC (15.1 and 8.1, respectively; P < .045). Expanded MSCs demonstrated similar phenotypes, but CFUs were significantly increased in BMA compared with BMAC (104 vs 68 CFUs, respectively; P < .001). Total protein concentration and cytokine profiling demonstrated great variability between BMA and BMAC and between patients. Most importantly, BMAC failed to concentrate MSCs in 6 of 8 samples. Conclusion: There is great variability in MSC concentration, total protein concentration, and cytokine profile between BMA and BMAC.

Automated summary

This study aimed to characterize bone marrow aspirate (BMA) versus bone marrow aspirate concentrate (BMAC) for mesenchymal stem cell (MSC) quantity, potency, and cytokine profile. The results showed significantly higher MSC concentration and CFU number in BMA compared to BMAC, with BMAC failing to concentrate MSC in 6 out of 8 samples.