Increased sheep lung vascular permeability caused by Escherichia coli endotoxin.
We infused Escherichia coli endotoxin, 0.07-1.33 microgram/kg, intravenously into chronically instrumented unanesthetized sheep and measured pulmonary arterial and left atrial pressures, lung lymph flow, lymph and blood plasma protein concentrations, and arterial blood gases. Endotoxin caused a biphasic reaction: an early phase of pulmonary hypertension and a long late phase of steady state increased pulmonary vascular permeability during which pulmonary arterial and left atrial pressures were not increased significantly and lung lymph flow was 5 times the baseline value. Lymph: plasma total protein concentration ratio during the late phase (0.76 +/- 0.04) was significantly (P less than 0.05) higher than during baseline (0.66 +/- 0.03). The lymph response was reproducible. Lung lymph clearance of endogenous proteins with molecular radii (r) 35.5 to 96 A was increased during the steady state late phase of the reaction, but, as during baseline, clearance decreased as r increased. The endotoxin reaction was similar to the reaction to infusing whole Pseudomonas bacteria, except that endotoxin had less effect on pressures during the steady state response and caused a relatively larger increase in lymph clearance of large proteins. We conclude that E. coli endotoxin in sheep causes a long period of increased lung vascular permeability and may have a greater effect on large solute pathways across microvessels than do Pseudomonas bacteria.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001798:Blood Proteins / Q000032:analysis; D002199:Capillary Permeability / Q000187:drug effects*; D004731:Endotoxins / Q000008:administration & dosage / Q000494:pharmacology*; D004926:Escherichia coli; D006976:Hypertension, Pulmonary / Q000139:chemically induced*; D007263:Infusions, Parenteral; D008196:Lymph / Q000032:analysis; D008208:Lymphatic System / Q000187:drug effects; D011506:Proteins / Q000032:analysis; D011552:Pseudomonas Infections / Q000503:physiopathology; D011651:Pulmonary Artery / Q000187:drug effects*; D018805:Sepsis / Q000503:physiopathology; D012756:Sheep
D001798:Blood Proteins; D004731:Endotoxins; D011506:Proteins