title: Lipopolysaccharide-binding protein, a surrogate marker of microbial translocation, is associated with physical function in healthy older adults.
abstract: BACKGROUND
  Physical function declines, and markers of inflammation increase with advancing age, even in healthy persons. Microbial translocation (MT) is the systemic exposure to mucosal surface microbes/microbial products without overt bacteremia and has been described in a number of pathologic conditions. We hypothesized that markers of MT, soluble CD14 (sCD14) and lipopolysaccharide (LPS) binding protein (LBP), may be a source of chronic inflammation in older persons and be associated with poorer physical function.
  
  
  METHODS
  We assessed cross-sectional relationships among two plasma biomarkers of MT (sCD14 and LBP), physical function (hand grip strength, short physical performance battery [SPPB], gait speed, walking distance, and disability questionnaire), and biomarkers of inflammation (C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), TNF-α soluble receptor 1 [TNFsR1]) in 59 older (60-89 years), healthy (no evidence of acute or chronic illness) men and women.
  
  
  RESULTS
  LBP was inversely correlated with SPPB score and grip strength (p = .02 and p < .01, respectively) and positively correlated with CRP (p = 0.04) after adjusting for age, gender, and body mass index. sCD14 correlated with IL-6 (p = .01), TNF-α (p = .05), and TNFsR1 (p < .0001). Furthermore, the correlations between LBP and SPPB and grip strength remained significant after adjusting for each inflammatory biomarker.
  
  
  CONCLUSIONS
  In healthy older individuals, LBP, a surrogate marker of MT, is associated with worse physical function and inflammation. Additional study is needed to determine whether MT is a marker for or a cause of inflammation and the associated functional impairments.
authors.affiliation: Section on Gerontology and Geriatric Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA. jstehle@wakehealth.edu
authors.forename: John R
authors.initials: JR
authors.lastname: Stehle
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Leng
authors.forename: Dalane W
authors.initials: DW
authors.lastname: Kitzman
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Nicklas
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kritchevsky
authors.forename: Kevin P
authors.initials: KP
authors.lastname: High
mesh_terms: D000209:Acute-Phase Proteins / Q000235:genetics / Q000378:metabolism*; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D018988:Bacterial Translocation / Q000502:physiology*; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003430:Cross-Sectional Studies; D016207:Cytokines / Q000032:analysis / Q000378:metabolism*; D005080:Exercise Test; D005260:Female; D005684:Gait / Q000502:physiology; D015577:Geriatric Assessment / Q000379:methods; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D007249:Inflammation / Q000097:blood* / Q000382:microbiology; D018836:Inflammation Mediators / Q000378:metabolism; D016014:Linear Models; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D015999:Multivariate Analysis; D010809:Physical Fitness / Q000502:physiology*; D012680:Sensitivity and Specificity; D000099231:Lipopolysaccharide-Binding Protein
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; D002352:Carrier Proteins; D016207:Cytokines; D018836:Inflammation Mediators; D008562:Membrane Glycoproteins; D000099231:Lipopolysaccharide-Binding Protein