title: Relationship between bilirubin concentration, coronary endothelial function, and inflammatory stress in overweight patients.
abstract: OBJECTIVE
  Bilirubin has antioxidant properties and may protect against atherosclerosis and coronary heart disease (CHD). Further, in patients with metabolic syndrome, hyperbilirubinemia is associated with attenuation of insulin resistance. The aim of the present study was to determine the relationship between serum bilirubin concentration and coronary endothelial function in overweight patients.
  
  
  METHODS
  The study population consisted of 107 patients without CHD who underwent coronary flow studies. Vascular reactivity was examined by intra-coronary administration of papaverine and nitroglycerin. Coronary endothelial function was evaluated by assessing the change in coronary artery diameter to papaverine [percent change in flow-mediated dilatation (%FMD)] and nitroglycerin (%NTG). Serum total bilirubin, high-sensitivity C-reactive protein (hs-CRP), high density lipoprotein-cholesterol (HDL-C), fasting plasma glucose and immunoreactive insulin levels were also measured, and the homeostasis model assessment insulin resistance (HOMA-IR) index was calculated. Patients were divided into two groups according to body mass index (BMI): an overweight group (BMI ≥ 25; n = 36) and a normal weight group (BMI < 25; n = 71).
  
  
  RESULTS
  In the overweight group, univariate analysis revealed that log-transformed total bilirubin was positively correlated with %FMD and HDL-C (r = 0.38, p< 0.05; r = 0.30, p < 0.05, respectively) and was inversely correlated with log-transformed hs-CRP and HOMA-IR (r = -0.45, p < 0.01; r = -0.45, p< 0.05, respectively). Multivariate analysis revealed that log-transformed hs-CRP was the only independent predictor of log-transformed total bilirubin (p< 0.05).
  
  
  CONCLUSIONS
  These results suggest that a high bilirubin level was associated with favorable coronary endothelial function in overweight patients. Further, the anti-inflammatory effects of bilirubin may mediate this effect.
authors.affiliation: Department of Cardiovascular, Respiratory and Metabolic Medicine, Graduate School of Medicine, Kagoshima University, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yoshino
authors.forename: Shuichi
authors.initials: S
authors.lastname: Hamasaki
authors.forename: Sanemasa
authors.initials: S
authors.lastname: Ishida
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Kataoka
authors.forename: Akiko
authors.initials: A
authors.lastname: Yoshikawa
authors.forename: Naoya
authors.initials: N
authors.lastname: Oketani
authors.forename: Keishi
authors.initials: K
authors.lastname: Saihara
authors.forename: Hideki
authors.initials: H
authors.lastname: Okui
authors.forename: Takuro
authors.initials: T
authors.lastname: Shinsato
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ichiki
authors.forename: Takuro
authors.initials: T
authors.lastname: Kubozono
authors.forename: So
authors.initials: S
authors.lastname: Kuwahata
authors.forename: Shoji
authors.initials: S
authors.lastname: Fujita
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kanda
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Nakazaki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Miyata
authors.forename: Chuwa
authors.initials: C
authors.lastname: Tei
mesh_terms: D000368:Aged; D001663:Bilirubin / Q000097:blood*; D003331:Coronary Vessels / Q000473:pathology*; D004730:Endothelium, Vascular / Q000473:pathology*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000209:etiology* / Q000473:pathology*; D008297:Male; D050177:Overweight / Q000150:complications*; D012307:Risk Factors
chemical_list: D001663:Bilirubin