The following article requires a subscription:

(Format: HTML, PDF)

In septic shock (SS), dysfunction of many organ systems develops during the course of the illness, although the mechanisms are not clear. In earlier studies, we reported that lysozyme-c (Lzm-S), a protein that is released from leukocytes and macrophages, was a mediator of the myocardial depression and vasodilation that develop in a canine model of Pseudomonas aeruginosa SS. Whereas both of these effects of Lzm-S are dependent on its ability to intrinsically generate hydrogen peroxide, we subsequently showed that Lzm-S can also deposit within the vascular smooth muscle layer of the systemic arteries in this model. In the present study, we extend our previous findings. We used a canine carotid artery organ bath preparation to study the time course and dose dependence of Lzm-S deposition within the vascular smooth muscle layer. We used a human aortic vascular smooth muscle cell preparation to determine whether Lzm-S can persistently inhibit contraction in this preparation. We also used a canine P. aeruginosa model to determine whether Lzm-S deposition might occur in other organs such as the kidney, liver, and small intestine. The results showed that, in the carotid artery organ bath preparation, Lzm-S deposition occurred within minutes of instillation and there was a dose-response effect. In the human aortic vascular smooth muscle cell preparation, Lzm-S inhibited contraction during a 4-day period. In the in vivo model, Lzm-S accumulated in the kidney and the superior mesenteric artery. In a canine renal epithelial preparation, we further showed that Lzm-S can be taken up by the renal tubules to activate inflammatory pathways. We conclude that Lzm-S can deposit in the systemic vasculature and kidneys in SS, where this deposition could lead to acute organ dysfunction.

(C) 2014 by the Shock Society