title: Relations of inflammatory markers to lipid levels and autonomic tone in patients with moderate and severe chronic kidney disease and in patients under maintenance hemodialysis.
abstract: OBJECTIVE
  Chronic kidney disease is associated with enhanced inflammatory response and autonomic dysfunction. Evidence exists of a potential interaction of inflammation and nervous system. We sought to investigate determinants of heart rate variability (HRV) and relations between the inflammatory markers C-reactive protein (CRP) and interleukin-6 (IL-6) and autonomic tone in patients with moderate and severe chronic kidney disease and in maintenance hemodialysis patients, and relations of CRP and IL-6 with clinical characteristics and lipid levels.
  
  
  METHODS
  This was a cross-sectional study of 51 hemodialysis and 53 moderate and severe chronic kidney disease patients. Autonomic tone was assessed using 24-hour HRV analysis in time and frequency domain. All patients underwent measurements of high sensitivity CRP, IL-6 and lipid levels.
  
  
  RESULTS
  CRP and IL-6 were elevated in the non-dialysis group at levels similar to hemodialysis patients. Hemodialysis patients had lower total cholesterol, LDL cholesterol and apolipoprotein B levels (p < 0.05), and in this group of patients lipids were related to CRP and IL-6 (p < 0.05). The inflammatory marker IL-6 was associated to HRV in the moderate and severe chronic kidney disease group (R = -0.4, p < 0.01 for standard deviation of RR intervals and very low frequency power, R = -0.5, p < 0.01 for standard deviation of all five-minute RR intervals, R = 0.35, p < 0.05, for total power and low frequency power). Adequacy of dialysis, but not the inflammatory markers, was associated to HRV in the hemodialysis group (R = 0.6, p < 0.01 for high frequency power).
  
  
  CONCLUSIONS
  Enhanced inflammatory response occurs already in stages 3 and 4 chronic kidney disease. IL-6 is related to HRV in these patients, but not in the hemodialysis group, suggesting that IL-6 may interact with autonomic tone in that stage of disease.
authors.affiliation: Second Department of Cardiology, Nikea General Hospital, Athens, Greece.
authors.forename: S N
authors.initials: SN
authors.lastname: Psychari
authors.forename: L
authors.initials: L
authors.lastname: Sinos
authors.forename: C
authors.initials: C
authors.lastname: Iatrou
authors.forename: G
authors.initials: G
authors.lastname: Liakos
authors.forename: T S
authors.initials: TS
authors.lastname: Apostolou
mesh_terms: D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D003430:Cross-Sectional Studies; D015716:Electrocardiography, Ambulatory; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000503:physiopathology*; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D006435:Renal Dialysis; D018709:Statistics, Nonparametric
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; D008055:Lipids; D002097:C-Reactive Protein