[The role of interstitial hyaluronan in acute lung injury]

The pulmonary interstitium may affect the movement of water, macromolecules, and inflammatory cells between capillaries and lymphatics. Hyaluronan (hyaluronic acid), a glycosaminoglycan of the interstitial matrix, helps to retain water in the lung interstitium and to exclude proteins. Marked reduction of interstitial hyaluronan by infusion of hyaluronidase decreased the resistance to fluid transport and decreased water retention in the interstitium, and thus accelerated lymphatic removal of fluid filtered across capillary walls. However, reduction of hyaluronan increased the accumulation of neutrophils in the lung and exacerbated acute lung injury caused by pancreatic elastase. Interstitial hyaluronan may protect against acute inflammatory changes in elastase-induced lung injury.