Attenuation of the acute-phase response in thermally injured rats by cholesterol-containing cationic liposomes used as a delivery system for gene therapy

Hypothesis: Cholesterol-containing cationic liposomes alone modulate the acute-phase response and cytokine expression in thermally injured rats and are an effective delivery system for gene therapy in trauma. Setting: Laboratory. Intervention: Fifty-six adult male Sprague-Dawley rats with a full-thickness scald burn covering 60% of total body surface area were randomly divided into 2 groups to receive either intravenous injections of cholesterol-containing cationic liposomes or saline (control). Main Outcome Measures: Body weights, muscle and liver dry-wet weights, serum levels of constitutive hepatic proteins, acute-phase protein levels, and cytokine levels were determined at 1, 2, 5, and 7 days after thermal injury. Results: Rats receiving cholesterol-containing cationic liposomes had less body weight loss, increased serum transferrin levels, and decreased serum α₁-acid glycoprotein levels when compared with controls (P<.05). Serum interleukin 1β and tumor necrosis factor α levels were decreased in rats receiving liposomes at 1 and 2 days after burn compared with controls (P<.05). Conclusions: These results suggest that cholesterol-containing cationic liposomes alone may have a beneficial effect in modulating the hypermetabolic response after burn injury by decreasing type 1 acute-phase proteins and the expression of the proinflammatory cytokines interleukin 1β and tumor necrosis factor α. Therefore, cholesterol-containing cationic liposomes appear to be suitable as a delivery system for gene therapy in trauma.