Loss of spatial organization and destruction of the pericellular matrix in early osteoarthritis in vivo and in a novel in vitro methodology.

Objectives: Current repair procedures for articular cartilage (AC) cannot restore the tissue's original form and function because neither changes in its architectural blueprint throughout life nor the respective biological understanding is fully available. We asked whether two unique elements of human cartilage architecture, the chondrocyte-surrounding pericellular matrix (PCM) and the superficial chondrocyte spatial organization (SCSO) beneath the articular surface (AS) are congenital, stable or dynamic throughout life. We hypothesized that inducing chondrocyte proliferation in vitro impairs organization and PCM and induces an advanced osteoarthritis (OA)-like structural phenotype of human cartilage.

Stress-vs-time signals allow the prediction of structurally catastrophic events during fracturing of immature cartilage and predetermine the biomechanical, biochemical, and structural impairment.

Objective: Trauma-associated cartilage fractures occur in children and adolescents with clinically significant incidence. Several studies investigated biomechanical injury by compressive forces but the injury-related stress has not been investigated extensively. In this study, we hypothesized that the biomechanical stress occurring during compressive injury predetermines the biomechanical, biochemical, and structural consequences.

Laminin-5 and type I collagen promote adhesion and osteogenic differentiation of animal serum-free expanded human mesenchymal stromal cells.

Mesenchymal stromal cells (MSC) are differentiation competent cells and may generate, among others, mature osteoblasts or chondrocytes in vitro and in vivo. Laminin-5 and type I collagen are important components of the extracellular matrix. They are involved in a variety of cellular and extracellular activities including cell attachment and osteogenic differentiation of MSC.

Modeling chondrocyte patterns by elliptical cluster processes.

Superficial zone chondrocytes (CHs) of human joints are spatially organized in distinct horizontal patterns. Among other factors, the type of spatial CH organization within a given articular surface depends on whether the cartilage has been derived from an intact joint or the joint is affected by osteoarthritis (OA). Furthermore, specific variations of the type of spatial organization are associated with particular states of OA.

Human mesenchymal stromal cells express CD14 cross-reactive epitopes.

Mesenchymal stromal cells (MSCs) do not express a unique definite epitope or marker gene. As such, minimal criteria were recently established for defining multipotent MSC. These criteria include expression of CD73, CD90, CD105, and a lack of hematopoietic marker expression.