Mobilization of Stem and Progenitor Cells in Septic Shock Patients

Septic shock is associated with multiple injuries to organs and tissues. These events may induce the regenerative response of adult stem cells. However, little is known about how endogenous stem cells are modulated by sepsis. This study analyzed the circulation of hematopoietic stem cells (HSCs), endothelial progenitor cells (EPCs) and very small embryonic-like stem cells (VSELs) in the peripheral blood of patients with septic shock. Thirty-three patients with septic shock and twenty-two healthy control subjects were enrolled in this prospective observational study. Blood samples were collected on the first, third and seventh days of septic shock. Populations of stem cells were analyzed by flow cytometry. Chemotactic mediators were analyzed by HPLC and ELISA. Populations of early HSCs (Lin-CD133+CD45+ and CD34+CD38-) were mobilized to the peripheral blood after an initial decrease. Mobilized HSCs showed significantly increased expression of Ki-67, a marker of cell proliferation. Circulating EPCs and VSELs were mobilized to the blood circulation upon the first day of sepsis. Patients with a greater number of Lin-CD133+CD45+HSCs and Lin-CD34+CD45-VSELs had a significantly lower probability of 60-day survival. The concentration of CXCL12 was elevated in the blood of septic patients, while the concentration of sphingosine-1-phosphate was significantly decreased. As an emergency early response to sepsis, VSELs and EPCs were mobilized to the peripheral blood, while the HSCs showed delayed mobilization. Differential mobilization of stem cell subsets reflected changes in the concentration of chemoattractants in the blood. The relationship between the probability of death and a large number of HSCs and VSELs in septic shock patients can be used as a novel prognostic marker and may provide new therapeutic approaches.