Pattern of collagen types and molecular structure of collagen in acute post-traumatic pulmonary fibrosis

Analyses of collagen types and their amino acid structures have been made with lungs obtained from eight patients who died from the adult respiratory distress syndrome after non-pulmonary trauma. Collagen in lungs from patients with the adult respiratory distress syndrome was twice as soluble as that in control lungs (p less than 0.01). The proportion of type III collagen in the whole organ as well as in the pepsin solubilised fraction was slightly but significantly raised (net increase of about 5-10% type III collagen (p less than 0.05]. Both type I and type III collagen from the patients contained less hydroxylysine than collagen from control lungs. The alterations in tissue composition described here and observed in normal wound healing support the notion that acute post-traumatic pulmonary fibrosis resembles a wound healing process in the lungs.