In vivo cartilage regeneration in a multi-layered articular cartilage architecture mimicking scaffold.

AIMS: Extracellular matrix (ECM) and its architecture have a vital role in articular cartilage (AC) structure and function. We hypothesized that a multi-layered chitosan-gelatin (CG) scaffold that resembles ECM, as well as native collagen architecture of AC, will achieve superior chondrogenesis and AC regeneration. We also compared its in vitro and in vivo outcomes with randomly aligned CG scaffold. METHODS: Rabbit bone marrow mesenchymal stem cells (MSCs) were differentiated into the chondrogenic lineage on scaffolds. Quality of in vitro regenerated cartilage was assessed by cell viability, growth, matrix synthesis, and differentiation. Bilateral osteochondral defects were created in 15 four-month-old male New Zealand white rabbits and segregated into three treatment groups with five in each. The groups were: 1) untreated and allogeneic chondrocytes; 2) multi-layered scaffold with and without cells; and 3) randomly aligned scaffold with and without cells. After four months of follow-up, the outcome was assessed using histology and immunostaining. RESULTS: In vitro testing showed that the secreted ECM oriented itself along the fibre in multi-layered scaffolds. Both types of CG scaffolds supported cell viability, growth, and matrix synthesis. In vitro chondrogenesis on scaffold showed an around 400-fold increase in collagen type 2 (COL2A1) expression in both CG scaffolds, but the total glycosaminoglycan (GAG)/DNA deposition was 1.39-fold higher in the multi-layered scaffold than the randomly aligned scaffold. In vivo cartilage formation occurred in both multi-layered and randomly aligned scaffolds treated with and without cells, and was shown to be of hyaline phenotype on immunostaining. The defects treated with multi-layered + cells, however, showed significantly thicker cartilage formation than the randomly aligned scaffold. CONCLUSION: We demonstrated that MSCs loaded CG scaffold with multi-layered zonal architecture promoted superior hyaline AC regeneration.Cite this article: Bone Joint Res 2020;9(9):601-612.

Lipofibromatosis: report of a rare paediatric soft tissue tumour.

The clinical, radiological and pathological features of a case of lipofibromatosis, a rare paediatric soft tissue neoplasm, are described. The tumour involved the foot of a male infant and was present at birth. Magnetic resonance imaging showed a lipomatous mass, with splaying of muscles of the sole by lobules of fat. Histopathological examination revealed typical findings of an admixture of mature adipose tissue and fibroblastic elements. The radiological and pathological features helpful in differentiating this entity from other fibro-fatty paediatric soft tissue tumours is discussed, and the relevant literature is briefly reviewed.