TISSUCOL-BASED SCAFFOLD IN THE TREATMENT OF KNEE CARTILAGE DEFECTS: EXPERIMENTAL RESURFACING BY EMBRIONYC STEMS CELLS

Abstract

Introduction: Recently, tissue engineering based on stem cells has emerged as a new discipline that amalgamates aspects from biology, engineering, material science and surgery and that has as goal the fabrication of functional new tissue to replace damage tissue. The aim of our study was to verify if the pluripotent cells derived from inner mass cell (ICM, Inner Cell Mass) of embryos at the first stages of development (blastocysts), seeded on Tissucol., maintaining them properties, and grow and form cartilage in chondral defects, when used for repair the lesion.

Methods: An osteochondral full thickness lesion was produced in the medial femoral condyles of twelve sheeps. The pluripotent cells were then isolated from feeder layer and seeded on fibrin glue before the transfer. We proceded with aspiration of ES cells in fibrinogen and successively addition of trombin at time to transplantation. The creation of full-thickness defects was performed in such a manner as to render it impermeable to blood-borne cells and signaling substances emanating from the subchondral bone-tissue spaces. After this, into the left knee 170 μl of Tissucol were inserted whether on right knee170 μl of Tissucol with 120.000 ES cells into the hole. The number of stems cells obtained initially correspond to the maximum quantity avalaible before the last differentiation of them.

The new tissue obtained was tested using the ICRS classification, and analysed biomechanically by the Artscan 200 series. We performed besides immunohistochemical evaluation of cartilage to check collagen type I.

Results: The compressive stiffness of the reparative tissue was higher in the treated group (Es cells + Tissucol) mean = 1.02 N than in the control group (Tissucol) mean = 0.68 N).

Four weeks after transplantation immunohistological analysis show in the treatment group cartilaginous tissue; The cells in the repair cartilage were round and arranged in numerous small clumps; the matrix showed strong metacromasia, indicating that this was hyaline cartilage. eight weeks after transplantation, the cells were largely distributed on the area and the repair tissue still resembled hyaline cartilage. After eight weeks the repair tissue implanted was fibrous with prevalence in extracellular matrix of Type II collagen.

Conclusion: Passage in fibrinogen and the addition of thrombin doesn’t alter the properties of the cells; Tissucol mimics embryonic environment and appears to be quite suitable and appropriately flexible delivery vehicle. This repair tissue manifests neither a arcade-like organization of its fibers nor a well-define zonal stratification of its chondrocytes but detection of Type I collagen rendering the pluripotent-cells-fibrin glue complex a possible candidate for the repair of cartilage lesions.