title: High levels of inflammatory biomarkers are associated with increased allele-specific apolipoprotein(a) levels in African-Americans.
abstract: BACKGROUND
  A role of inflammation for cardiovascular disease (CVD) is established. Lipoprotein(a) [Lp(a)] is an independent CVD risk factor where plasma levels are determined by the apolipoprotein(a) [apo(a)] gene, which contains inflammatory response elements.
  
  
  METHODS
  We investigated the effect of inflammation on allele-specific apo(a) levels in African-Americans and Caucasians. We determined Lp(a) levels, apo(a) sizes, allele-specific apo(a) levels, fibrinogen and C-reactive protein (CRP) levels in 167 African-Americans and 259 Caucasians.
  
  
  RESULTS
  Lp(a) levels were increased among African-Americans with higher vs. lower levels of CRP [<3 vs. > or =3 mg/liter (143 vs. 108 nmol/liter), P = 0.009] or fibrinogen (<340 vs. > or =340 mg/liter, P = 0.002). We next analyzed allele-specific apo(a) levels for different apo(a) sizes. No differences in allele-specific apo(a) levels across CRP or fibrinogen groups were seen among African-Americans or Caucasians for small apo(a) sizes (<22 kringle 4 repeats). Allele-specific apo(a) levels for medium apo(a) sizes (22-30 kringle 4 repeats) were significantly higher among African-Americans, with high levels of CRP or fibrinogen compared with those with low levels (88 vs. 67 nmol/liter, P = 0.014, and 91 vs. 59 nmol/liter, P < 0.0001, respectively). No difference was found for Caucasians.
  
  
  CONCLUSIONS
  Increased levels of CRP or fibrinogen are associated with higher allele-specific medium-sized apo(a) levels in African-Americans but not in Caucasians. These findings indicate that proinflammatory conditions result in a selective increase in medium-sized apo(a) levels in African-Americans and suggest that inflammation-associated events may contribute to the interethnic difference in Lp(a) levels between African-Americans and Caucasians.
authors.affiliation: Department of Medicine, University of California, Davis, Sacramento, California 95817, USA.
authors.forename: Erdembileg
authors.initials: E
authors.lastname: Anuurad
authors.forename: Jill
authors.initials: J
authors.lastname: Rubin
authors.forename: Alan
authors.initials: A
authors.lastname: Chiem
authors.forename: Russell P
authors.initials: RP
authors.lastname: Tracy
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Pearson
authors.forename: Lars
authors.initials: L
authors.lastname: Berglund
mesh_terms: D001741:Black or African American / Q000235:genetics*; D000483:Alleles; D053241:Apoprotein(a) / Q000097:blood*; D015415:Biomarkers; D002097:C-Reactive Protein / Q000032:analysis*; D005260:Female; D005340:Fibrinogen / Q000032:analysis*; D006801:Humans; D007249:Inflammation / Q000208:ethnology*; D008297:Male; D044465:White People
chemical_list: D015415:Biomarkers; D005340:Fibrinogen; D002097:C-Reactive Protein; D053241:Apoprotein(a)