A type I cell-specific protein is a biochemical marker of epithelial injury in a rat model of pneumonia.
In this study we determined whether the alveolar fluid content of a specific epithelial type I cell protein, rTI40, can be used as a biochemical marker for lung injury. A model of alveolar epithelial injury was developed by instilling Pseudomonas aeruginosa bacteria (PA103) into the airspaces of anesthetized, ventilated rats. After 6 h, the alveolar fluid content of rTI40 from PA103-treated rats was increased over 80-fold in comparison to alveolar fluid from control rats (P < 0.05). This increase in rTI40 correlated with both morphological evidence of injury to alveolar epithelial type I cells and increased permeability of the alveolar epithelium to protein tracers. In contrast, the lactate dehydrogenase activity of alveolar fluid from PA103-treated rats was elevated only threefold over control values at 6 h (P < 0.05). In a second study using a less injurious strain of P. aeruginosa (PA103 exsA::omega), the alveolar fluid content of rTI40 was the same as control values. These findings indicate that the alveolar fluid content of a type I cell-specific protein can be used as a sensitive and specific biochemical marker of type I cell injury.
McElroy
M C
MC
Department of Anesthesia, University of California, San Francisco 94143.
Pittet
J F
JF
Hashimoto
S
S
Allen
L
L
Wiener-Kronish
J P
JP
Dobbs
L G
LG
D000818:Animals; D015415:Biomarkers; D001826:Body Fluids / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D010539:Permeability; D011014:Pneumonia / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology*; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D011552:Pseudomonas Infections; D011650:Pulmonary Alveoli / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D015415:Biomarkers; D011506:Proteins; D007770:L-Lactate Dehydrogenase