Functional heterogeneity of rat hepatic and alveolar macrophages: effects of chronic ethanol administration

Chronic ethanol consumption is associated with increased incidence of hepat ic and pulmonary infections. To determine if this is correlated with altere d macrophage activity, we analyzed the functional properties of cells isola ted sequentially from the Liver and lung of rats fed a liquid diet containi ng ethanol (35% of calories) or malto-dextrin control for 9-12 weeks. Hepat ic and alveolar macrophages from control animals were found to exhibit dist inct morphologic and functional properties. Thus, hepatic macrophages were highly vacuolated and appeared larger and more irregular in shape than alve olar macrophages, These cells also displayed greater phagocytic activity an d random migration. In contrast, lung macrophages produced more superoxide anion and nitric oxide, and exhibited enhanced chemotactic activity toward the complement fragment C5a. Whereas administration of ethanol to rats for 9-12 weeks resulted in decreased chemotaxis and superoxide anion production by alveolar macrophages, cell adhesion molecule expression was reduced in hepatic macrophages, Nitric oxide production and inducible nitric oxide syn thase protein expression were decreased in both macrophage populations. The se effects were not observed after 3-6 weeks of ethanol administration to r ats. Our results suggest that changes in macrophage functioning may play a role in decreased host defense following chronic ethanol exposure.