4 MARKERS OF COLLAGEN-METABOLISM AS POSSIBLE INDICATORS OF DISEASE INTHE ADULT-RESPIRATORY-DISTRESS-SYNDROME

During the adult respiratory distress syndrome(ARDS), an irreversible fibrotic process can occur extremely rapidly. To establish indices of ARDS in pneumonia as well as the severity of the lung fibrosis, we hav e undertaken for the first time a study of four markers of collagen me tabolism obtained from both bronchoalveolar lavage fluid (BALF) and se rum: Type I (CI), Type III (CIII), N-terminal peptide of Type III proc ollagen (PIIINP), and galactosylhydroxylysylglucosyltransferase activi ty (GGT). We studied 61 patients (13 coma controls, 29 with pneumonia, and 19 with ARDS). In BALF, the average values of Cl, CIII, PIIINP, a nd GGT were significantly higher in ARDS than in the control patients. The values for patients with pneumonia, although increased, were sign ificantly lower than those in ARDS for CI, CIII, and PIIINP In serum, the mean CI and PIIINP were significantly increased in pneumonia and A RDS, but the mean CIII was significantly increased only in ARDS compar ed with the control group. Significant positive linear correlations we re observed for ARDS between CI and CIII or PIIINP and CIII in BALF an d serum. Such correlations were observed for pneumonia only in serum. Molecular mass determinations demonstrated that CI- and CIII-related a ntigens in BALF were essentially intact triple helices of collagens or procollagens. Among patients with histologically defined interstitial fibrosis, the level of PIIINP in BALF was significantly higher for th ose with an additional intraalveolar fibrosis. In conclusion, measurem ents of these collagen markers may be useful for assessing disease act ivity and reflecting the flux of collagen molecules in the lung.