SEP-16: RESPONSES OF THE HEMATOPOIETIC STEM AND PROGENITOR CELL COMPARTMENT DURING ACUTE PHASE OF MOUSE CLP SEPSIS DEPEND ON ITS SEVERITY AND OUTCOME

INTRODUCTION:Sepsis deregulates early hematopoiesis and can shift stem cells into an “emergency program”, but dynamics of this phenomenon are unclear. We aimed to characterize outcome-dependent changes occurring in the hematopoietic stem and progenitor cells (HSPCs) compartment during acute polymicrobial sepsis. METHODS:Forty female CD-1 mice underwent medium-grade (50% mortality) cecal ligation and puncture (CLP). Mice were stratified into predicted to die (P-DIE) or survive (P-SUR) using their body temperature and clinical score (98% specificity) and were sacrificed in P-DIE/P-SUR pairs within 48 h of CLP. Bone marrow (BM) cell pellet and supernatant were analyzed. RESULTS:The BM cellularity decreased in all CLP mice (vs. healthy); this depletion was 2-fold greater in P-DIE vs. P-SUR. Similarly, LSK (Lin-ckit+Sca-1+) and short-term-HSC (Lin-ckit+Sca-1+CD48+CD150+) populations decreased in P-DIE mice (by approx. 2-fold and 2.3-fold; p