Circulating endothelial progenitor cells inversely associate with organ dysfunction in sepsis

Endothelial dysfunction is a primary contributor to sepsis-related organ dysfunction and death. In sepsis animal models, endothelial progenitor cells (EPC) have contributed to vascular repair. The role of endothelial progenitor cells as a biomarker for organ dysfunction is still unknown. We hypothesized that circulating numbers of endothelial progenitor cells would be associated with improved outcomes in sepsis. Prospective, observational single-center cohort study in adult intensive care units at Grady Memorial Hospital, an affiliate of Emory University, from July 2007 through April 2009. Peripheral blood was obtained from 95 patients with sepsis, 37 intensive care unit controls, and 51 healthy controls, of whom only 86 patients with sepsis were used in the analysis because we were not able to obtain enough blood in 9 sepsis patients. Clinical data were obtained, and organ dysfunction was measured by Sepsis-Related Organ Failure Assessment (SOFA) score. Endothelial progenitor cells were assessed by a colony-forming unit (CFU) assay in which peripheral blood mononuclear cells were isolated using Ficoll density-gradient centrifugation and cultured in growth media. The patients with sepsis had significantly lower mean endothelial progenitor cell colony counts compared with intensive care unit controls (p = 0.035) and healthy controls (p = 0.0005). There was no difference in colony counts between ICU controls and healthy controls (p = 0.81). In the sepsis patients, EPC CFU numbers inversely associated with SOFA score, adjusting for mortality (r (2) = 0.05, p = 0.04). Increased circulating endothelial progenitor cells inversely correlate with organ dysfunction in sepsis patients.