title: Endothelial dysfunction and increased oxidative stress in mitochondrial diseases.
abstract: MDs (mitochondrial diseases) are a clinically heterogeneous group of disorders characterized by impairment of the respiratory chain function with altered oxidative phosphorylation. We tested the hypothesis that the function of vascular endothelium is affected by increased oxidative stress in MDs. A total of 12 patients with MDs and pair-matched controls were studied. Endothelial function was assessed by measuring FMD (flow-mediated vasodilation) of brachial and common femoral arteries. The test was repeated after vitamin C (500 mg, twice a day) and E (400 mg, once a day) supplementation for 30 days and 90 days after vitamin withdrawal. FMD was reduced in patients compared with controls [AUC/τ (time-averaged area under the curve) for the brachial artery, 1.05±0.24 compared with 4.19±0.59% respectively, P<0.001; AUC/τ for the femoral artery, 0.98±0.19 compared with 2.36±0.29% respectively, P=0.001; values are means±S.E.M.] and correlated (brachial artery) with plasma lactate (r=-0.63, P<0.01). Urinary 8-iso-PGF2α (8-iso-prostaglandin F2α) was higher in patients than controls (505.6±85.9 compared with 302.5±38.7 pg/mg of creatinine; P<0.05) and correlated with plasma lactate (r=0.70, P<0.05). Immunohistochemical analysis showed 8-iso-PGF2α staining in MD-affected striated muscle cells and in blood vessels in muscle biopsies of patients. Antioxidant vitamins transiently restored FMD in patients [ΔAUC/τ (change in AUC/τ) for the brachial artery, +1.38±0.49%, P<0.05; ΔAUC/τ for the femoral artery, +0.98±0.24%, P<0.01] but had no effect on FMD in controls (brachial artery, -1.3±0.63%; and common femoral artery, -0.58±0.30%), thus abolishing the differences between patients and controls. The results of the present study indicate that oxidative stress is increased and is, at least partly, responsible for endothelial dysfunction in MDs.
authors.affiliation: Department of Medicine, Section of Internal Medicine, University of Verona, Verona, Italy. pietro.minuz@univr.it
authors.forename: Pietro
authors.initials: P
authors.lastname: Minuz
authors.forename: Cristiano
authors.initials: C
authors.lastname: Fava
authors.forename: Gaetano
authors.initials: G
authors.lastname: Vattemi
authors.forename: Guido
authors.initials: G
authors.lastname: Arcaro
authors.forename: Matteo
authors.initials: M
authors.lastname: Riccadonna
authors.forename: Paola
authors.initials: P
authors.lastname: Tonin
authors.forename: Alessandra
authors.initials: A
authors.lastname: Meneguzzi
authors.forename: Maurizio
authors.initials: M
authors.lastname: Degan
authors.forename: Valeria
authors.initials: V
authors.lastname: Guglielmi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Lechi
authors.forename: Giuliano
authors.initials: G
authors.lastname: Tomelleri
mesh_terms: D000328:Adult; D015237:Dinoprost / Q000031:analogs & derivatives / Q000652:urine; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D028361:Mitochondrial Diseases / Q000503:physiopathology*; D009569:Nitric Oxide / Q000502:physiology; D018384:Oxidative Stress; D017382:Reactive Oxygen Species; D014664:Vasodilation
chemical_list: D017382:Reactive Oxygen Species; C075750:8-epi-prostaglandin F2alpha; D009569:Nitric Oxide; D015237:Dinoprost