Urinary Desmosine Excretion as a Marker of Lung Injury in the Adult Respiratory Distress Syndrome* COL Michael F. Tenholdet; M.D., F.C.C.R; LTC Krishnan R. Rajagopal, M.D.; LTC (P) Yancy Y Phillips, M.D., F.C.C.R; LTC Thom.as A. Dillard, M.D., F.C.C.R; 1.£0 L. Bennett, M.D., F.C.C.R; CPT Thom.as G. Mundie; and COL Claude]. Tellis, M.D., F.C.C.R Desmosine, the intermolecular and intramolecular crosS link between the chains of elastin polypeptide, may be useful as a marker of a lung injury in adult respiratory distress syndrome (ARDS). A radioimmunoassay for rabbit antibody developed against desmosine, conjugated to b0vine serum albumin, can detect as little as 100 pg of desmosine in plasma or urine. Desmosine is not metabolically absorbed, reused, or catabolized by the body, but rather eliminated unchanged in the urine as low molecular weight peptides. The lung is relatively rich in elastin, and we reasoned that a timed collection could be used as an index of elastin degradation in vivo. A 2-h collection of urine for desmosine assay was obtained at the time of SwanGanz catheter insertion in 41 consecutive patients. On the basis of clinical and initial Swan-Ganz catheter data, the patients were assigned to one of three groups: an ARDS group (n 12); a cardiogenic pulmonary edema (CPE) group (n = 12); and a critically ill, nonpulmonary edema group

(NPE, n= 17). The mean urine desmosine concentration (mgIL) for the ARDS group (0.728±0.22 SE) differed from the CPE group (0.149±0.07; p