title: Aged mice are unable to mount an effective myeloid response to sepsis.
abstract: The elderly have increased morbidity and mortality following sepsis; however, the cause(s) remains unclear. We hypothesized that these poor outcomes are due in part to defects in innate immunity, rather than to an exaggerated early inflammatory response. Young (6-12 wk) or aged (20-24 mo) mice underwent polymicrobial sepsis, and subsequently, the aged mice had increased mortality and defective peritoneal bacterial clearance compared with young mice. No differences were found in the magnitude of the plasma cytokine responses. Although septic aged mice displayed equivalent or increased numbers of circulating, splenic, and bone marrow myeloid cells, some of these cells exhibited decreased phagocytosis, reactive oxygen species production, and chemotaxis. Blood leukocyte gene expression was less altered in aged versus young mice 1 d after sepsis. Aged mice had a relative inability to upregulate gene expression of pathways related to neutrophil-mediated protective immunity, chemokine/chemokine receptor binding, and responses to exogenous molecules. Expression of most MHC genes remained more downregulated in aged mice at day 3. Despite their increased myeloid response to sepsis, the increased susceptibility of aged mice to sepsis appears not to be due to an exaggerated inflammatory response, but rather, a failure to mount an effective innate immune response.
authors: Department of Surgery, University of Florida College of Medicine, Gainesville, FL 32610;
authors: Dina C
authors: DC
authors: Nacionales
authors: Lori F
authors: LF
authors: Gentile
authors: Erin
authors: E
authors: Vanzant
authors: M Cecilia
authors: MC
authors: Lopez
authors: Angela
authors: A
authors: Cuenca
authors: Alex G
authors: AG
authors: Cuenca
authors: Ricardo
authors: R
authors: Ungaro
authors: Yi
authors: Y
authors: Li
authors: Tezcan Ozrazgat
authors: TO
authors: Baslanti
authors: Azra
authors: A
authors: Bihorac
authors: Frederick A
authors: FA
authors: Moore
authors: Henry V
authors: HV
authors: Baker
authors: Christiaan
authors: C
authors: Leeuwenburgh
authors: Lyle L
authors: LL
authors: Moldawer
authors: Philip A
authors: PA
authors: Efron
mesh_terms: D000368:Aged; D000818:Animals; D018925:Chemokines / Q000097:blood / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D005260:Female; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics / Q000276:immunology*; D007962:Leukocytes / Q000276:immunology / Q000378:metabolism; D008285:Major Histocompatibility Complex / Q000235:genetics / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D022423:Myeloid Cells / Q000276:immunology* / Q000378:metabolism; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism; D010587:Phagocytosis / Q000235:genetics / Q000276:immunology; D017382:Reactive Oxygen Species / Q000276:immunology / Q000378:metabolism; D019707:Receptors, Chemokine / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018805:Sepsis / Q000097:blood / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D013154:Spleen / Q000276:immunology / Q000378:metabolism; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology
chemical_list: D018925:Chemokines; D017382:Reactive Oxygen Species; D019707:Receptors, Chemokine