Lung microvessel injury from peritoneal abscesses and gram-negative bacteremia.
To analyze the effect of an extrathoracic focus of infection on lung vessel wall structure, we produced peritoneal abscesses in the rat, over a period of 3 to 7 weeks, by implanting capsules containing live gram-negative bacteria (3.0 x 10(7) Escherichia coli and 5.0 x 10(7) Bactercides fragilis) with an adjutant. We document here by arteriography, morphometric analysis, and high resolution microscopy, microvessel cell injury, and wall remodeling. In the sepsis-injured lung, both dilated and thick-walled microvessels are present. The walls of dilated vessels are disrupted by extensive endothelial and precursor smooth muscle cell injury. In thick-walled vessels these cells are hypertrophied, and the precursor smooth muscle cells express filaments, demonstrating a shift toward a contractile phenotype. Infiltrating monocytic cells focally consolidate alveolar regions. In the residual nonconsolidated regions, alveolar-capillary membrane cells are attenuated and the capillaries dilated. Vessel changes after 7 weeks are similar to those after 3 weeks but alveolar-capillary membrane injury is more extensive. These structural changes, including the development of precursor smooth muscle cells, may contribute to the known increase in reactivity of these lung vessels to challenge by vasoactive agents.
Jones
R
R
Department of Anesthesia, Massachusetts General Hospital-East, Charlestown.
Kirton
O C
OC
D018784:Abdominal Abscess / Q000382:microbiology / Q000473:pathology*; D000818:Animals; D016470:Bacteremia / Q000473:pathology*; D001442:Bacteroides Infections / Q000473:pathology*; D001441:Bacteroides fragilis; D004730:Endothelium, Vascular / Q000473:pathology; D004927:Escherichia coli Infections / Q000473:pathology*; D008168:Lung / Q000098:blood supply*; D008297:Male; D008566:Membranes; D008833:Microcirculation / Q000000981:diagnostic imaging / Q000502:physiology; D010532:Peritoneal Diseases / Q000382:microbiology / Q000473:pathology*; D011650:Pulmonary Alveoli / Q000098:blood supply; D011859:Radiography; D051381:Rats; D017207:Rats, Sprague-Dawley