Morphological and ultrastructural analysis of normal, injured and osteoarthritic human knee menisci

The human meniscus plays a crucial role for transmission and distribution of load across the knee, as well as shock absorption, joint stability, lubrication, and congruity. The aim of this study was to compare the complex geometry, and unique ultrastructure and tissue composition of the meniscus in healthy (control) and pathological conditions to provide understanding of structural changes that could be helpful in the future design of targetted therapies and improvement of treatment indications. We analyzed meniscus samples collected from 3 healthy multi-organ donors (median age, 66 years), 5 patients with traumatic meniscal tear (median age, 41 years) and 3 patients undergoing total knee replacement (TKR) for end-stage osteoarthritis (OA) (median age, 72 years). We evaluated the extracellular matrix (ECM) organization, the appearance and distribution of areas of calcification, and modifications of cellular organization and structure by electron microscopy and histology. The ECM structure was similar in specimens from traumatic meniscus tears compared to those from patients with late-stage OA, showing disorganization of collagen fibers and increased proteoglycan content. Cells of healthy menisci showed mainly diffuse chromatin and well preserved organelles. Both in traumatic and in OA menisci, we observed increased chromatin condensation, organelle degeneration, and cytoplasmic vacuolization, a portion of which contained markers of autophagic vacuoles. Areas of calcification ...
Source: European Journal of Histochemistry - Category: Biomedical Science Source Type: research