Summary

Cells isolated and cultured from meniscal debris were identified to be mesenchymal stem cells and found to be capable of differentiating along three lineages.

Abstract

The purpose is to characterize and culture mesenchymal stem cells derived from meniscal debris of patients with meniscal injury, as well as analyze their surface markers and multilineage differentiation potential. Cells in meniscal debris from patients with meniscal injury were isolated by enzymatic digestion, cultured in vitro to the third passage and analyzed to observe morphology and growth. Third-passage cultures were also analyzed for immunophenotype and ability to differentiate into tri-lineages. After 4-6 days in culture, cells in meniscal debris showed a long fusiform shape and adhered to the plastic walls of the culture dish. After 8-10 days, cell clusters and colonies were observed. Third-passage cells showed uniform morphology and good proliferation. They expressed surface markers typical of mesenchymal stem cells (CD29, CD90, CD105), but not surface markers typical of hematopoietic stem cells (CD34, CD45). Cultures were induced to differentiate into bone, adipose and cartilage, cells showed positive staining for Alizarin Red as well as for alkaline phosphatase activity for formation of mineralization nodes and early osteogenic marker, Oil Red O for lipid vacuoles, Toluidine blue and Col II immunohistochemical staining for the cartilage-specific matrix. Cells isolated and cultured from meniscal debris were identified to be mesenchymal stem cells and found to be capable of differentiating along three lineages. The existence of MSCs in meniscal debris and showed that they can be cultured and differentiated, opening the door to studies examining their potential for meniscal regeneration.