Evidence of hyaluronic acid and hyaluronic acid binding sites on human corneal endothelium.

A highly specific hyaluronic acid (HA) recognizing protein (HABR) was used to study whether the human corneal endothelium is covered by HA and to quantify the amount. Tritiated high molecular weight HA was used to determine the capacity of the human endothelium to bind exogenous HA. Human corneas were obtained from keratoconus patients having corneal transplantation and from postmortem eyes. The corneas were immersed in a 4% formaldehyde solution containing 1% cetylpyridine chloride for histochemistry, frozen for biochemistry, or used for 3H-HA (Mr 3 x 10(6) binding. For the biochemical determinations, 125I-labeled HABR was used. Tritiated HA was used for the binding experiment. A specific layer of HA covering the endothelial cells of the corneal buttons was demonstrated. The biochemical analysis also revealed the presence of HA. Finally, the human endothelial cells had specific hyaluronic acid binding sites.