Lung production of platelet-activating factor acetylhydrolase in oleic acid-induced acute lung injury

Lipid bodies in innate immune response to bacterial and parasite infections

“…Increased lipid body accumulation in leukocytes has been observed in both clinical and experimental infectious conditions, including in cells from blood and peritoneum in bacterial sepsis [27,[43][44][45], bronchoalveolar lavage (BAL) of patients and experimental animals with acute respiratory distress [46,47]; in septic arthritis [31] and foamy differentiated macrophages from granuloma or pleural lavage from mycobacterial infections [48][49][50][51]. Accumulating evidence indicating that lipid body formation during infections is a well-regulated phenomenon that may have implications for microbial pathogenesis have been achieved over recent years.…”

Differential expression of platelet-activating factor acetylhydrolase in lung macrophages

“…Likewise, Gomes et al (19) found moderately decreased values for plasma PAF acetylhydrolase activity in patients with sepsis and septic shock. In contrast, PAF acetylhydrolase activity has been consistently shown to increase in BAL fluid in both critically ill human patients and in animal models of acute lung injury (20,34,39,48).…”

“…6 and 8), although smaller leukocytes, most likely neutrophils in the BAL, showed positive PAF acetylhydrolase staining (see below). Numerous studies have documented increased PAF acetylhydrolase activity in BAL fluid in both critically ill patients and in animal models of acute lung injury (20,34,39). Grissom et al (20) demonstrated that PAF acetylhydrolase activity is increased in BAL fluid from patients with ARDS and detected PAF acetylhydrolase mRNA in alveolar macrophages.…”

“…However, this RT-PCR result was obtained from BAL cells that were characterized as having anywhere from 35 to 63% neutrophils present. In a porcine model of oleic acid-induced acute lung injury, Salluh et al (39) demonstrated increased BAL fluid PAF acetylhydrolase activity and observed PAF acetylhydrolase immunostaining of macrophages and epithelial cells in the lung tissue. In their studies, increased PAF acetylhydrolase activity did not correlate with increased protein content in the lavage fluid, and the increase in PAF acetylhydrolase activity detected was several hours after the increase in protein content.…”

The platelet activating factor (PAF) signaling cascade in systemic inflammatory responses

“…In critically-ill patients plasma PAF AH activity was correlated with levels of neopterin, a macrophage marker [62], and was detected in alveolar macrophages [67], consistent with these in vitro observations. PAF AH was also detected in lung macrophages in a porcine model of ALI [68]. In vitro and in vivo experiments indicate that plasma PAF AH levels may be increased by synthetic glucocorticoids [7], which are commonly given to critically-ill patients and in systemic inflammatory syndromes, potentially by altering macrophage synthesis.…”