Pulmonary capillary endothelium-bound angiotensin-converting enzyme activity in acute lung injury.
BACKGROUND
Pulmonary capillary endothelium-bound (PCEB) angiotensin-converting ectoenzyme (ACE) activity alteration is an early, sensitive, and quantifiable lung injury index in animal models. We hypothesized that (1) PCEB-ACE alterations can be found in patients with acute lung injury (ALI) and (2) PCEB-ACE activity correlates with the severity of lung injury and may be used as a quantifiable marker of the underlying pulmonary capillary endothelial dysfunction.


RESULTS
Applying indicator-dilution techniques, we measured single-pass transpulmonary hydrolysis of the synthetic ACE substrate (3)H-benzoyl-Phe-Ala-Pro (BPAP) in 33 mechanically ventilated, critically ill patients with a lung injury score (LIS) ranging from 0 (no lung injury) to 3.7 (severe lung injury) and calculated the kinetic parameter A(max)/K(m). Both parameters decreased early during the ALI continuum and were inversely related to APACHE II score and LIS. Hydrolysis decreased with increasing cardiac output (CO), whereas 2 different patterns were observed between CO and A(max)/K(m).


CONCLUSIONS
PCEB-ACE activity decreases early during ALI, correlates with the clinical severity of both the lung injury and the underlying disease, and may be used as a quantifiable marker of underlying pulmonary capillary endothelial dysfunction.
Orfanos
S E
SE
Critical Care Department, Evangelismos Hospital, University of Athens Medical School, Greece. stelmar@ath.forthnet.gr
Armaganidis
A
A
Glynos
C
C
Psevdi
E
E
Kaltsas
P
P
Sarafidou
P
P
Catravas
J D
JD
Dafni
U G
UG
Langleben
D
D
Roussos
C
C
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008168:Lung / Q000098:blood supply / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides / Q000378:metabolism; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000175:diagnosis / Q000201:enzymology*; D015996:Survival Rate; D014316:Tritium
D009842:Oligopeptides; D014316:Tritium; C029689:benzoylphenylalanyl-alanyl-proline; D007703:Peptidyl-Dipeptidase A