No abstract

An impaired cochlear perfusion seems to be an important etiopathogenetic event in idiopathic sudden sensorineural hearing loss (ISSNHL). Recently, oxidative stress has been proposed as risk factors of microvascular damage. This observational study aimed to evaluate the possible role of oxidative stress in ISSNHL. In thirty-nine ISSNHL patients and seventy healthy subjects serum reactive oxygen species concentrations (ROS) and total antioxidant capacity (TAC) were measured by spectrophotometric methods on F.R.E.E. analyzer (Diacron International, Italy). Moreover, a global oxidative stress index (Oxidative-INDEX), reflecting both oxidative and antioxidant counterparts, was also calculated. 25/39 patients showed oxidative stress due to ROS levels significantly higher than controls (348.2 ± 84.8 vs. 306.75 ± 46.7 UCarr; p = 0.001). The Oxidative-INDEX was significantly higher in patients than in controls (0.75 ± 2.4 vs. -0.0007 ± 1.28 AU, p = 0.03). As oxidative stress is a key determinant in endothelial dysfunction, our findings could suggest vascular impairment involvement in ISSNHL etiopathogenesis.

Renal transplant patients have a pattern of increased oxidant stress that is counterbalanced by an enhancement of the antioxidant mechanisms. Besides the well-known risk factors, the authors found that anemia is an independent risk factor for an increase of ROS. Further studies are needed to evaluate whether the correction of anemia might prevent or reduce the oxidative stress in renal transplant patients.

Background: Oxidative stress is present in cardiovascular diseases (CVDs), and hyperhomocysteinemia, an independent risk factor for these diseases, may play a role by inducing production of oxygen free radicals. Methods: To evaluate the possible role of homocysteine (Hcy) in inducing oxidative stress in coronary artery disease (CAD), plasma Hcy was measured in 68 consecutive cardiovascular patients, and plasma malondialdehyde (MDA), both free and total (free + bound), was measured in 40 patients with CAD (18 with chronic stable angina and 22 with unstable angina). As controls, we tested 70 healthy volunteers. Hcy was measured by an immunoenzymatic method and MDA, an index of lipid peroxidation, by gas chromatography–mass spectrometry. Results: Plasma Hcy concentrations were significantly higher in cardiovascular patients than in controls (10.2 vs 8.9 μmol/L; P <0.0002), with no significant difference between values in the stable and unstable angina subgroups. Similarly, total MDA was significantly higher in the CAD group than in the controls (2.6 vs 1.3 μmol/L; P <0.00001), again with no significant difference between stable and unstable angina patients. By contrast, free MDA, which was significantly higher in the CAD patients than the controls (0.4 vs 0.2 μmol/L; P <0.00001), was also significantly higher in the unstable than in the stable angina group (0.5 vs 0.3 μmol/L; P <0.03). However, no correlation was observed among Hcy and free and total MDA. Conclusions: Our findings show that a moderate increase of Hcy is associated with CVD but that Hcy at the detected values cannot be considered completely responsible for oxidative damage. That lipid peroxidation is involved in CAD is shown by our observation of significantly increased plasma free and total MDA concentrations compared with controls. Moreover, free MDA values discriminated between unstable and chronic stable angina, and could thus represent a new diagnostic tool.