Lipopolysaccharide-binding protein, a surrogate marker of microbial translocation, is associated with physical function in healthy older adults

J Gerontol A Biol Sci Med Sci. 2012 Nov;67(11):1212-8. doi: 10.1093/gerona/gls178. Epub 2012 Sep 7.

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.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute-Phase Proteins / genetics
  • Acute-Phase Proteins / metabolism*
  • Aged
  • Aged, 80 and over
  • Aging / physiology
  • Bacterial Translocation / physiology*
  • Biomarkers / blood
  • Biomarkers / metabolism
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cross-Sectional Studies
  • Cytokines / analysis
  • Cytokines / metabolism*
  • Exercise Test
  • Female
  • Gait / physiology
  • Geriatric Assessment / methods
  • Hand Strength / physiology
  • Humans
  • Inflammation / blood*
  • Inflammation / microbiology
  • Inflammation Mediators / metabolism
  • Linear Models
  • Male
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism*
  • Middle Aged
  • Multivariate Analysis
  • Physical Fitness / physiology*
  • Sensitivity and Specificity

Substances

  • Acute-Phase Proteins
  • Biomarkers
  • Carrier Proteins
  • Cytokines
  • Inflammation Mediators
  • Membrane Glycoproteins
  • lipopolysaccharide-binding protein