Abstract 11493: Gene Therapy with BRCA1 Reduces Systemic Inflammatory Response and Multiple Organ Failure and Improves Survival in Experimental Sepsis
Sepsis-related complications and mortality remain a major clinical problem in critically ill cardiothoracic patients. Increased activation of cell death pathways and unresolved DNA repair have been implicated as key upstream mediators of sepsis-induced multiple organ dysfunction and death. We hypothesized that gene therapy with BRCA1, a critical regulator of DNA-damage repair and cell survival, may be a novel target to limit sepsis-induced multiple organ failure and death. We employed two models of experimental sepsis and multiple organ failure - cecal ligation perforation (CLP) and thioglyocollate-induced inflammation. Experimental sepsis was associated with markedly reduced BRCA1 expression in the vasculature, heart, kidney, and liver, in conjunction with evidence for increased apoptosis, DNA fragmentation and altered RAD51 foci formation. C57Bl/6J mice underwent sham or CLP surgery 3 days following treatment with either human BRCA1 adenovirus (AdBRCA1) or the adeno-CMV-null vector (Adnull). The 24 hours post-CLP mortality was 2.8% vs. 17.9% (P<0.001) and the median post-CLP survival was 50.5 hours vs. 33 hours (log rank test P<0.05) for AdBRCA1- vs. Adnull-treated mice, respectively. AdBRCA1 therapy significantly blunted CLP-associated cardiac, pulmonary, hepatic and renal dysfunction, and improved systemic hemodynamics. AdBRCA1 treatment also reduced cardiac and vascular reactive oxygen species production, coincident with a reduction in apoptosis and γH2A.X foci formation, a marker of double strand DNA breaks. Lastly, thioglycollate-challenged AdBRCA1-treated mice displayed blunted peritoneal neutrophil recruitment and a dampened proinflammatory cytokine profile, with marked reductions in proinflammatory chemokine KC, IL-6, IFNγ, CXCL-2 and MCP-1 and up-regulation of anti-inflammatory IL-10 levels. BRCA1 is a novel and previously unrecognized regulator of multiple organ failure and death in response to experimental sepsis. These effects appear to be mediated in part through a pleiotropic and multiorgan anti-inflammatory response that limits DNA double stand breaks and reduces cellular apoptosis. Translational studies of BRCA1-based therapies to limit sepsis related mortality and morbidity are indicated.
- © 2011 by American Heart Association, Inc.