March 13th, 2004
AOSSM Specialty Day

Tissue engineering of the meniscus: In-vivo study with a cell-seeded meniscus collagen scaffold in sheep

Authors:
  1. Vladimir Martinek MD, PhD, Technical University Munich, Munich, Germany
  2. Peter Ueblacker MD, Technical University Munich, Munich, Germany
  3. Klaus Braeun MD, Technical University Munich, Munich, Germany
  4. Stephan Nitzschke, Technical University Munich, Munich, Germany
  5. Bernd Gaensbacher MD, Prof., Technical University Munich, Munich, Germany
  6. Andreas B. Imhoff MD, Prof., Univ. of Munich Ortho Sports Med., Munich, Germany
Objective:  Therapeutic options following meniscus loss - allograft transplantation or implantation of the Collagen Meniscus Implant (CMI), offer only limited chances for a long-term success. For this reason, the development of biologic materials for meniscus replacement is ongoing intensively. In the following experimental study, we evaluated the effect of tissue engineering on biochemical, histological and biomechanical properties of the meniscus transplant in-vivo.
Methods:  Autologous fibrochondrocytes were obtained per biopsy from the medial meniscus of the right knee joints of adult female Merino sheep (n=39). The cell were released from the matrix, cultured in-vitro under standard conditions and seeded on CMI matrices (n=16). The seeded scaffolds were kept in in-vitro culture for 3 weeks and then used for autologous transplantation of the medial menisci. The transplantated specimen were obtained after 3 and 6 months for macroscopical, histological, biochemical and biomechanical evaluation and compared with unseeded CMI controls (n=14) as well as with meniscus-resected controls (n=9).
Results:  The evaluation of the lameness score did not differ between the groups. Histologically, a significant difference was found between the seeded and unseeded scaffolds. In the tissue engineered menisci, an enhanced superficial and deep vascularisation, an accelerated re-modelling of the collagen scaffold, a higher content of extracellular matrix and a lower number of cells were noted in comparison with the unseeded controls. A small regenerate found in 2 of 5 cases in the resection control group showed histologically a dense, less-organized, high-cellular fibrous scar tissue. The content of glycosaminoglycans (2.2 % vs. 0.5%; p< 0.05) and the content of collagen type II (6.63 % vs. 1,31%; p=0.16) were increased in the group of the cell-seeded scaffolds in comparison to the contents in the unseeded scaffolds. An improvement of the biomechanical properties, however, could not be demonstrated.
Conclusions:  The tissue engineering of the meniscus in form of in-vitro seeding of the collagen meniscus prosthesis with autologous fibrochondrocytes demonstrates a marked histological and biochemical improvement of the meniscus transplant in sheep. However, further development of the methods, especially of the scaffold and of the cell-seeding procedure will prove the feasibility of this idea for human applications.
Keywords:
  1. Meniscus
 Categories:
  1. BASIC SCIENCE: Knee - Meniscus