Skip Navigation LinksHome > June 2009 - Volume 37 - Issue 6 > Detrimental hemodynamic and inflammatory effects of micropar...
Critical Care Medicine:
doi: 10.1097/CCM.0b013e3181a00629
Laboratory Investigations

Detrimental hemodynamic and inflammatory effects of microparticles originating from septic rats*

Mortaza, Satar MD; Martinez, M Carmen PhD; Baron-Menguy, Céline PhD; Burban, Mélanie ST; de la Bourdonnaye, Mathilde ST; Fizanne, Lionel PhD; Pierrot, Marc MD; Calès, Paul MD, PhD; Henrion, Daniel PhD; Andriantsitohaina, Ramaroson PhD; Mercat, Alain MD, PhD; Asfar, Pierre MD, PhD; Meziani, Ferhat MD, PhD

Collapse Box

Abstract

Objective: Microparticles (MPs) are membrane vesicles with procoagulant and proinflammatory properties released during cell activation and might be potentially involved in the pathophysiology of septic shock. This study was designed to assess the effects of MPs from septic origin on the systemic hemodynamics as well as on the inflammatory, oxidative, and nitrosative stresses.

Design: A prospective, randomized, controlled experimental study with repeated measurements.

Setting: Investigational animal laboratory.

Subjects: Forty healthy rats were randomly allocated to three groups: 10 animals inoculated with MPs isolated from control rats (cMPs), 15 animals inoculated with MPs isolated from sham rats (shMPs), and 15 animals inoculated with MPs isolated from rats with peritonitis (sMPs).

Interventions: Rats were anesthetized, mechanically ventilated, and infused with the same amount of cMPs, shMPs, or sMPs. We measured the heart rate, mean arterial pressure, carotid artery, and portal vein blood flows. Hemodynamic parameters were recorded during 7 hours, and then animals were killed. Aorta and heart were harvested for further in vitro tissue analyses.

Measurements and Main Results: 1) The cellular origin (phenotype) but not the circulating concentration of MPs was different in septic rats, characterized by a significant increase in leukocyte-derived MPs. 2) sMPs but not cMPs or shMPs decreased mean arterial pressure without any effect on carotid artery and portal vein blood flows. 3) Rats inoculated with sMPs exhibited an increase in superoxide ion production and nuclear factor kappa B activity, overexpression of inducible nitric oxide synthase with subsequent nitric oxide overproduction and decrease in endothelial nitric oxide synthase activation.

Conclusions: Rats with sepsis induced by peritonitis exhibited a specific phenotype of MPs. Inoculation of sMPs in healthy rats reproduced hemodynamic, septic inflammatory patterns, associated with oxidative and nitrosative stresses.

© 2009 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins

Article Tools

Share

Search for Similar Articles
You may search for similar articles that contain these same keywords or you may modify the keyword list to augment your search.