title: Association between n-3 polyunsaturated fatty acid content of red blood cells and inflammatory biomarkers in patients with peripheral artery disease.
abstract: OBJECTIVE
  The n-3 polyunsaturated fatty acids are dietary components derived from fish oil with beneficial cardiovascular effects that may relate in part to anti-inflammatory properties. Peripheral artery disease (PAD) is characterized by a marked proinflammatory state. We hypothesized that the n-3 polyunsaturated fatty acids content of red blood cells (omega-3 index) would be correlated with biomarkers of inflammation and vascular function in a PAD cohort.
  
  
  METHODS
  This was a cross-sectional study of subjects who presented to an outpatient vascular surgery clinic for evaluation of PAD. We used linear regression to evaluate the independent association between the omega-3 index, inflammatory biomarkers (C-reactive protein [CRP], intercellular adhesion molecule-1, interleukin-6, and tumor-necrosis-factor-α) and endothelial function (brachial artery flow mediated dilation).
  
  
  RESULTS
  64 subjects (61 claudicants and three with critical limb ischemia) were recruited for the study. The mean CRP level was 5.0 ± 5.0 mg/L, and the mean omega-3 index was 5.0% ± 1.8%. In an unadjusted model, the omega-3 index was negatively associated with CRP (38% increase in CRP for one standard deviation decrease in the omega-3 index; P = .007), which remained significant after adjustment for age, body mass index, smoking, ankle-brachial index, and high-density lipoprotein (33%; P = .04). There was also evidence for independent associations between the omega-3 index and IL-6 (P = .001). There were no significant associations between the omega-3 index and vascular function tests.
  
  
  CONCLUSIONS
  In a cohort of patients with PAD, the omega-3 index was inversely associated with biomarkers of inflammation even after adjustment for covariates including the ankle-brachial index. Because patients with PAD have a high inflammatory burden, further studies should be conducted to determine if manipulation of omega-3 index via dietary changes or fish oil supplementation could improve inflammation and symptoms in these patients.
authors.affiliation: Department of Surgery, University of California, San Francisco, San Francisco, Calif; Department of Surgery, Veterans Affairs Medical Center, San Francisco, Calif. Electronic address: marlene.grenon@ucsfmedctr.org.
authors.forename: S Marlene
authors.initials: SM
authors.lastname: Grenon
authors.forename: Michael S
authors.initials: MS
authors.lastname: Conte
authors.forename: Emily
authors.initials: E
authors.lastname: Nosova
authors.forename: Hugh
authors.initials: H
authors.lastname: Alley
authors.forename: Karen
authors.initials: K
authors.lastname: Chong
authors.forename: William S
authors.initials: WS
authors.lastname: Harris
authors.forename: Eric
authors.initials: E
authors.lastname: Vittinghoff
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Owens
mesh_terms: D000368:Aged; D055109:Ankle Brachial Index; D015415:Biomarkers / Q000097:blood; D001916:Brachial Artery / Q000378:metabolism / Q000503:physiopathology; D002097:C-Reactive Protein / Q000032:analysis*; D003430:Cross-Sectional Studies; D004730:Endothelium, Vascular / Q000378:metabolism / Q000503:physiopathology; D004912:Erythrocytes / Q000737:chemistry*; D015525:Fatty Acids, Omega-3 / Q000097:blood*; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D058729:Peripheral Arterial Disease / Q000097:blood* / Q000175:diagnosis / Q000276:immunology / Q000503:physiopathology; D011237:Predictive Value of Tests; D011379:Prognosis; D014664:Vasodilation
chemical_list: D015415:Biomarkers; D015525:Fatty Acids, Omega-3; D018836:Inflammation Mediators; D002097:C-Reactive Protein