Thrombospondin as a component of the extracellular matrix of epiretinal membranes: comparisons with cellular fibronectin.

We compared the distribution of the adhesive extracellular matrix glycoproteins thrombospondin and cellular fibronectin in epiretinal membranes. A total of nine membranes were investigated with immunohistochemical techniques. Thrombospondin and cellular fibronectin immunoreactivity were observed in seven of the specimens and immunostaining for the two glycoproteins was co-localised in four of the membranes. The findings indicate that thrombospondin contributes to the extracellular glycoprotein content of epiretinal membranes and is frequently co-distributed with cellular fibronectin in the tissue. As a consequence, thrombospondin may play a role in the assembly of the extracellular matrix of epiretinal membranes.