Interaction between synoviocytes and extracellular matrix in vitro.

Synoviocyte adhesion, migration, and proliferation are essential in the growth of pannus and the subsequent invasion of cartilage in inflammatory arthritis. These cellular functions are regulated by the extracellular matrix.' In vitro studies of synoviocytes have previously demonstrated that they display abnormal phenotypic properties, including a transformation-like morphology manifested by cell overlapping and focus formation.2 3 Abnormal synoviocyte phenotype has been shown to be strongly influenced by extracellular matrix; synoviocytes exhibit extensive focus formation when plated on exogenous fibronectin rich matrices or when primed to switch endogenous matrix production from a collagen enriched to a fibronectin enriched type.3 To determine if the influence of matrix on synoviocyte morphology is associated with effects on synoviocyte adhesion and growth, we studied the effect of purified matrix components and a cell free matrix preparation isolated from human synovium on the attachment, spreading, and proliferation of human synoviocytes in vitro.