title: Black currant anthocyanins normalized abnormal levels of serum concentrations of endothelin-1 in patients with glaucoma.
abstract: OBJECTIVE
  Our recent study, which involved a randomized, placebo-controlled, double-masked 24-month trial (Ophthalmologica 2012;228:26-35), revealed that oral administration of black currant anthocyanins (BCACs) slowed down the visual field deterioration and elevation of ocular blood flow of open-angle glaucoma (OAG). To elucidate the underlying mechanisms of these BCAC-induced effects, as possible factors affecting glaucomatous optic neuropathy, changes of serum endothelin-1 (ET-1), nitric oxide (NO), and antioxidative activities were examined in the present study.
  
  
  METHODS
  From among patients with OAG who participated in the randomized, placebo-controlled, double-masked trial, serum specimens were obtained from BCAC-treated (n=19) or placebo-treated (n=19) patients at baseline and every 6 months. Healthy volunteers (n=20) with age and gender matching the patients were used as a control. Serum ET-1 concentration, [NO2(-)] and [NO2(-) + NO3(-)] levels, advanced oxidation protein products (AOPP), and antioxidant activities were measured by using commercially available kits.
  
  
  RESULTS
  At the trial baseline, serum ET-1 concentrations were significantly lower in patients with OAG (BCACs, 3.18±1.06 pg/mL; placebo, 3.44±0.84 pg/mL) than those in healthy volunteers (4.38±1.03 pg/mL) (one-way analysis of variance and a Tukey's multiple comparison post hoc test, P<0.05). Upon administration of BCACs, serum ET-1 concentrations increased to the levels of those in healthy volunteers during the 24-month period. In contrast, those of placebo-treated patients remained at lower levels (3.82±1.14 pg/mL). While [NO2(-)] and [NO2(-)+NO3(-)] levels, AOPP, and antioxidative activities of patients from both the BCACs and placebo groups showed comparable levels to those of healthy subjects at baseline, no significant changes were observed during the observational period in either the BCAC or placebo groups.
  
  
  CONCLUSIONS
  Among the possible beneficial effects of BCACs toward visual field progression in patients with OAG, our present results suggest that BCACs caused normalization of serum ET-1 levels, and this may modulate ET-1-dependent regulation of the ocular blood hemodynamics.
authors.affiliation: Department of Ophthalmology, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Yoshida
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Ohguro
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohguro
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000704:Analysis of Variance; D000872:Anthocyanins / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D000975:Antioxidants / Q000378:metabolism; D016022:Case-Control Studies; D004311:Double-Blind Method; D019332:Endothelin-1 / Q000097:blood*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000150:complications / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D009901:Optic Nerve Diseases / Q000209:etiology / Q000517:prevention & control; D031965:Ribes / Q000737:chemistry*; D016896:Treatment Outcome; D014794:Visual Fields / Q000187:drug effects
chemical_list: D000872:Anthocyanins; D000975:Antioxidants; D019332:Endothelin-1; D009569:Nitric Oxide