Ke. Weltywolf et al., BACTERIAL PRIMING INCREASES LUNG INJURY IN GRAM-NEGATIVE SEPSIS, American journal of respiratory and critical care medicine, 158(2), 1998, pp. 610-619
Citations number
36
Categorie Soggetti
Emergency Medicine & Critical Care","Respiratory System
Sepsis syndrome is a leading cause of acute respiratory distress syndr
ome (ARDS), but the development of acute lung injury is highly variabl
e for reasons that are poorly understood. We hypothesized that nonleth
al systemic exposure to gram-negative bacteria, with its consequent ac
tivation of inflammatory processes, would increase functional and stru
ctural lung injury on a second exposure to live organisms, as compared
with exposure of naive animals. Sixteen adult baboons received 1 to 2
X 10(10) colony-forming-units (cfu)/kg Escherichia coli by intravenou
s infusion. Eight animals received live bacteria as a single infusion,
whereas the other eight received 10% of the total dose as heat-killed
organisms (priming dose) 12 h before the live infusion. Pulmonary gas
exchange and hemodynamics were monitored for 48 h or until blood pres
sure could not be maintained. The animals were killed and one lung was
processed for electron microscopy and morphometry. Group data were co
mpared through analysis of variance (ANOVA). The systemic circulatory
responses to the bacterial challenge were similar, although less sever
e shock occurred in primed animals. In contrast, primed animals had in
creased structural damage involving lung epithelium and endothelium, a
nd showed increased cellularity of the interstitium. The morphologic e
vidence of increased lung injury in septic animals with prior exposure
to heat-killed bacteria suggests that prior activation of systemic in
flammatory responses is a contributing factor in the pathogenesis of A
RDS.