title: Circulating Biomarkers of Gut Barrier Function: Correlates and Nonresponse to Calcium Supplementation among Colon Adenoma Patients.
abstract: BACKGROUND
  Gut barrier dysfunction contributes to several gastrointestinal disorders, including colorectal cancer, but factors associated with intestinal hyperpermeability have been minimally studied in humans.
  
  
  METHODS
  We tested the effects of two doses of calcium (1.0 or 2.0 g/d) on circulating biomarkers of gut permeability [anti-flagellin and anti-lipopolysaccharide (LPS) Ig, measured via ELISA] over a 4-month treatment period among colorectal adenoma patients in a randomized, double-blinded, placebo-controlled clinical trial (n = 193), and evaluated the factors associated with baseline levels of these biomarkers.
  
  
  RESULTS
  Baseline concentrations of anti-flagellin IgA and anti-LPS IgA were, respectively, statistically significantly proportionately higher by 11.8% and 14.1% among men, 31.3% and 39.8% among those with a body mass index ≥ 35 kg/m(2), and 19.9% and 22.0% among those in the upper relative to the lowest sex-specific tertile of waist circumference. A combined permeability score (the summed optical densities of all four biomarkers) was 24.3% higher among women in the upper tertile of plasma C-reactive protein (Ptrend < 0.01). We found no appreciable effects of supplemental calcium on anti-flagellin or anti-LPS Igs.
  
  
  CONCLUSIONS
  Our results suggest that (i) men and those with higher adiposity may have greater gut permeability, (ii) gut permeability and systemic inflammation may be directly associated with one another, and (iii) supplemental calcium may not modify circulating levels of gut permeability biomarkers within 4 months.
  
  
  CONCLUSIONS
  Our findings may improve the understanding of the factors that influence gut permeability to inform development of treatable biomarkers of risk for colorectal cancer and other health outcomes.
authors.affiliation: Department of Epidemiology, Emory University, Atlanta, Georgia. Laney Graduate School, Emory University, Atlanta, Georgia.
authors.forename: Baiyu
authors.initials: B
authors.lastname: Yang
authors.affiliation: Department of Epidemiology, Emory University, Atlanta, Georgia. Winship Cancer Institute, Emory University, Atlanta, Georgia.
authors.forename: Roberd M
authors.initials: RM
authors.lastname: Bostick
authors.affiliation: Center for Inflammation, Immunity, and Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia.
authors.forename: Hao Quang
authors.initials: HQ
authors.lastname: Tran
authors.affiliation: Center for Inflammation, Immunity, and Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Gewirtz
authors.affiliation: Epidemiology Research Program, American Cancer Society, Atlanta, Georgia.
authors.forename: Peter T
authors.initials: PT
authors.lastname: Campbell
authors.affiliation: Department of Epidemiology, Emory University, Atlanta, Georgia. Winship Cancer Institute, Emory University, Atlanta, Georgia. vfedirk@emory.edu.
authors.forename: Veronika
authors.initials: V
authors.lastname: Fedirko
mesh_terms: D000236:Adenoma / Q000378:metabolism*; D000328:Adult; D000368:Aged; D015415:Biomarkers; D002118:Calcium / Q000378:metabolism*; D003106:Colon / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000378:metabolism*; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D015415:Biomarkers; D002118:Calcium