Cruciate ligament-derived mesenchymal stem cells: a potential cell source for cartilage regeneration

Background: Mesenchymal stem cells (MSCs) have been widely investigated for potential in tissue regeneration. The aim of this study was to compare the proliferation and induced differentiation potentials of MSCs isolated from bone marrow (BMSCs), adipose (AMSCs) and cruciate ligament (CLMSCs). Methods: BMSCs, AMSCs and CLMSCs were isolated and identified by flow cytometry with CD markers. Their clonogenicity, proliferation and multi-differentiation capacities were also analyzed. The mRNA expression of adipogenic, osteogenic, and chondrogenic markers at basal state and after multi-lineage inductions was examined using quantitative real-time polymerase chain reaction (qRT-PCR). Results: BMSCs, AMSCs and CLMSCs showed similar positive expression for CD29, CD90, and negative for CD45. Comparative analyses suggested the superior colony forming and proliferation capacity in CLMSCs. When induced toward adipo-, osteo- and chondro-lineages, BMSCs, AMSCs and CLMSCs could successfully differentiate toward target lineages. At basal state and after multi-lineage inductions, AMSCs expressed the highest level of adipogenic markers [peroxisome proliferator-activated receptor gamma 2 (PPAR gamma 2) and CCAAT enhancer binding protein alpha (c/EBP alpha)]; BMSCs expressed the highest level of osteogenic markers [Alpl, Bglap, Runx2, bone morphogenetic protein 2 (Bmp2), and Spp 1]; CLMSCs expressed the highest level of chondrogenic markers (Col2A1, Acan, and Sox9). Conclusions: This study demonstrates that CLMSCs and AMSCs exhibit superiority in cell proliferation compared to BMSCs. CLMSCs can be a potential cell source for clinical application in cartilage regeneration.