Matrix-encapsulation cell-seeding technique to prevent cell detachment during arthroscopic implantation of matrix-induced autologous chondrocytes.

The research study explores a technique for maintaining viable cells within a construct during arthroscopic implantation, a process often accompanied by high fluid flow that can detach cells. Researchers tested this method on horses and found that it allows for a sufficient number of viable cells to remain in the construct while also promoting tissue formation.

Research Method

• The study began with arthroscopic osteochondral biopsy specimens taken from the medial femoral trochlea of eight horses.
• The chondrocytes were isolated using collagenase digestion and then expanded in M199 media until they reached confluency.
• After 10 to 12 days, the cultures were trypsinized and the cells were suspended in culture media.
• Then, the cells were seeded on a culture dish and in a flask. Once an extracellular matrix formed, a polyglycolic/polylactic acid disk was placed in the culture dish.
• The cells obtained from the flasks were then seeded onto the polymer and encapsulated by lifting the monolayer of cells and the matrix from the bottom of the dish using surgical forceps.

Study Execution and Findings

• On days 1, 3, 5, 7, and 9, they checked cell viability using calcein fluorescence. Cell attachment to the polymer was also evaluated using environmental scanning electron microscopy.
• Of the eight horses, six were implanted with the original naive cell-polymer constructs, while the other two were implanted with cells transduced with an adenoviral vector carrying green fluorescent protein (AdGFP).
• At 4 weeks and 8 weeks, biopsy samples of the repaired tissue were evaluated using second-look arthroscopy, biopsy, histochemistry, and confocal laser scanning microscopy.
• The results confirmed that the encapsulation method maintained cell viability and attachment to the polymer. The best period for implantation was found to be between days 7 and 9.
• Furthermore, tissue repair in the subjects implanted with AdGFP-transduced cells after 4 weeks showed fluorescent cells, indicating cell viability. At the 8-week mark, newly formed tissue that adhered well to the bone and surrounding cartilage was observed.

Conclusions

• The matrix-encapsulation cell-seeding technique successfully counteracted the damaging effects of the high-pressure fluid flow that occurs during arthroscopic implantation, thus preserving a significant number of viable cells.
• This method can mitigate cellular loss during arthroscopic implantation of cell-polymer constructs carried out using a fluid pump, suggesting a possible advancement in the field of tissue engineering and regenerative medicine.