Matrix metalloproteinase inhibitor prevents acute lung injury after cardiopulmonary bypass.
BACKGROUND
Acute lung injury (ALI) after cardiopulmonary bypass (CPB) results from sequential priming and activation of neutrophils. Activated neutrophils release neutral serine, elastase, and matrix metalloproteinases (MMPs) and oxygen radical species, which damage alveolar-capillary basement membranes and the extracellular matrix, resulting in an ALI clinically defined as adult respiratory distress syndrome (ARDS). We hypothesized that treatment with a potent MMP and elastase inhibitor, a chemically modified tetracycline (CMT-3), would prevent ALI in our sequential insult model of ALI after CPB.


RESULTS
Anesthetized Yorkshire pigs were randomized to 1 of 5 groups: control (n=3); CPB (n=5), femoral-femoral hypothermic bypass for 1 hour; LPS (n=7), sham bypass followed by infusion of low-dose Escherichia coli lipopolysaccharide (LPS; 1 microgram/kg); CPB+LPS (n=6), both insults; and CPB+LPS+CMT-3 (n=5), both insults plus intravenous CMT-3 dosed to obtain a 25-micromol/L blood concentration. CPB+LPS caused severe lung injury, as demonstrated by a significant fall in PaO(2) and an increase in intrapulmonary shunt compared with all groups (P<0.05). These changes were associated with significant pulmonary infiltration of neutrophils and an increase in elastase and MMP-9 activity.


CONCLUSIONS
All pathological changes typical of ALI after CPB were prevented by CMT-3. Prevention of lung dysfunction followed an attenuation of both elastase and MMP-2 activity. This study suggests that strategies to combat ARDS should target terminal neutrophil effectors.
Departments of Surgery and Cardiovascular Perfusion, SUNY Health Science Center at Syracuse, NY, 13210, USA.
D E
DE
Carney
C J
CJ
Lutz
A L
AL
Picone
L A
LA
Gatto
N S
NS
Ramamurthy
L M
LM
Golub
S R
SR
Simon
B
B
Searles
A
A
Paskanik
K
K
Snyder
C
C
Finck
H J
HJ
Schiller
G F
GF
Nieman
D000208:Acute Disease; D000818:Animals; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D018093:Gelatinases / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008168:Lung / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D008171:Lung Diseases / Q000139:chemically induced / Q000201:enzymology / Q000209:etiology* / Q000473:pathology / Q000517:prevention & control*; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors*; D009504:Neutrophils / Q000473:pathology; D010196:Pancreatic Elastase / Q000378:metabolism; D011183:Postoperative Complications / Q000517:prevention & control*; D011480:Protease Inhibitors / Q000494:pharmacology*; D013552:Swine; D013754:Tetracyclines / Q000494:pharmacology*
D008070:Lipopolysaccharides; D011480:Protease Inhibitors; D013754:Tetracyclines; C117155:tetracycline CMT-3; D010196:Pancreatic Elastase; D018093:Gelatinases; D008666:Metalloendopeptidases