OBJECTIVE:

Plasma gelsolin is a circulating actin-binding protein that serves a protective role against tissue injuries. Depletion of plasma gelsolin in systemic inflammation may contribute to adverse outcomes. We examined the role of plasma gelsolin in animal models of sepsis.

DESIGN:

Animal and laboratory experiments.

SETTING:

Academic research laboratory.

SUBJECTS:

Adult male mice.

INTERVENTIONS:

Mice subjected to endotoxin or cecal ligation and puncture (CLP) were treated with exogenous plasma gelsolin or placebo.

MEASUREMENTS AND MAIN RESULTS:

We document the depletion of plasma gelsolin (25-50% of normal) in murine models of sepsis associated with the presence of circulating actin within 6 hrs of septic challenge. Repletion of plasma gelsolin leads to solubilization of circulating actin aggregates and significantly reduces mortality in endotoxemic mice (survival rates were 88% in the gelsolin group vs. 0% in the saline group, p < .001) and in CLP-challenged mice (survival rates were 30% in the gelsolin group vs. 0% in the saline group, p = .001). Plasma gelsolin repletion also shifted the cytokine profile of endotoxemic mice toward anti-inflammatory (plasma interleukin-10 levels were 205 +/- 108 pg/mL in the gelsolin group vs. 39 +/- 29 pg/mL in the saline group, p = .02).

CONCLUSIONS:

We propose that circulation of particulate actin is a marker for sepsis-induced cell injury, that plasma gelsolin has a crucial protective role in sepsis, and that gelsolin replacement represents a potential therapy for this common lethal condition.