OBJECTIVE: To determine the effects of polymyxin B sulfate in rats fed by total parenteral nutrition on norepinephrine excretion, macrophage tumor necrosis factor production, and bacterial translocation. DESIGN: Randomized animal study. SETTING: A university teaching hospital in Seattle, Wash. MATERIALS AND METHODS: Three groups of rats were studied: chow plus intravenous saline, total parenteral nutrition, or total parenteral nutrition supplemented with polymyxin B sulfate. After 5 days, urinary excretion of norepinephrine and epinephrine was calculated, peritoneal and alveolar macrophages were cultured, and their spontaneous and lipopolysaccharide-stimulated tumor necrosis factor production was measured. Mesenteric lymph nodes were cultured for bacteria. RESULTS: Rats fed by total parenteral nutrition had increased urine norepinephrine excretion (33%) and alveolar macrophage tumor necrosis factor production (80%) and trends for increased epinephrine excretion and bacterial translocation compared with rats fed chow. Alveolar but not peritoneal macrophage tumor necrosis factor production was significantly related to norepinephrine excretion (r = .5, P < .01). The addition of polymyxin B to total parenteral nutrition decreased weight gain (P < .05), urinary norepinephrine excretion (P < .01), and alveolar macrophage tumor necrosis factor production (P < .05) compared with rats fed by total parenteral nutrition. Polymyxin B also tended to decrease the magnitude of bacterial translocation. CONCLUSIONS: Alveolar macrophage tumor necrosis factor production appears to be influenced by sympathetic nervous activity. Total parenteral nutrition-induced endotoxemia may indirectly alter macrophage function by stimulating sympathetic nervous activity.
OBJECTIVE: To determine the effects of polymyxin B sulfate in rats fed by total parenteral nutrition on norepinephrine excretion, macrophage tumor necrosis factor production, and bacterial translocation. DESIGN: Randomized animal study. SETTING: A university teaching hospital in Seattle, Wash. MATERIALS AND METHODS: Three groups of rats were studied: chow plus intravenous saline, total parenteral nutrition, or total parenteral nutrition supplemented with polymyxin B sulfate. After 5 days, urinary excretion of norepinephrine and epinephrine was calculated, peritoneal and alveolar macrophages were cultured, and their spontaneous and lipopolysaccharide-stimulated tumor necrosis factor production was measured. Mesenteric lymph nodes were cultured for bacteria. RESULTS:Rats fed by total parenteral nutrition had increased urine norepinephrine excretion (33%) and alveolar macrophage tumor necrosis factor production (80%) and trends for increased epinephrine excretion and bacterial translocation compared with rats fed chow. Alveolar but not peritoneal macrophage tumor necrosis factor production was significantly related to norepinephrine excretion (r = .5, P < .01). The addition of polymyxin B to total parenteral nutrition decreased weight gain (P < .05), urinary norepinephrine excretion (P < .01), and alveolar macrophage tumor necrosis factor production (P < .05) compared with rats fed by total parenteral nutrition. Polymyxin B also tended to decrease the magnitude of bacterial translocation. CONCLUSIONS:Alveolar macrophage tumor necrosis factor production appears to be influenced by sympathetic nervous activity. Total parenteral nutrition-induced endotoxemia may indirectly alter macrophage function by stimulating sympathetic nervous activity.