Comparison between embryonic stem cell versus adult stem cell to restore cartilage repair: an experimental study

This study aimed at comparing quantitative and qualitative results of experiments based on embryo cells (embryonic stem-like – ESL) relative to medullary stimulation (BMS) for chondral lesions treatment of Medial Femur Condyle (MFC) in sheep. Male ESL cells embedded in fibrin glue were engrafted into chondral defects in the MFC of 4 ewes. An identical defect was created in other 4 sheep and treated with Nanofracture technique for bone marrow stimulation. Sheep were euthanized at 12 months from surgery. The evaluation of regenerated tissue was performed by macroscopic, histological, immunohistochemical (collagen type II) and Fluorescent in situ Hybridization (FISH) assay. When the BMS and ESL scores at 12 months were compared, statistically significant differences in some macroscopic categories scores were found between the two treatments: ESL samples recorded significantly higher matrix staining score (p= 0.01), and tidemark score (p = 0.04); BMS samples had significantly higher points in subchondral bone category (p = 0.01). No significant differences were found in the others categories. At 12 months, collagen type II immunostaining was detected and marked in all ESL samples. In BMS samples the repaired tissue resulted positive for type II collagen especially around the performed perforations. FISH showed positive intranuclear signals only in the ESL cells found in the newly formed tissue. This study demonstrated that ESL cells, engrafted into chondral defects in sheep knee condyles, enhanced the quality of the regeneration of articular hyaline cartilage. In addition, it confirmed that BMS technique can provide for a good subchondral bone remodeling and a fair quantitative filling of chondral defects.