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A strong correlation was found between lens GSH and lens TBARS concentrations in the diabetic group. This emphasized the vital role of GSH as an antioxidant in the lens over the other antioxidant parameters, e.g., enzymes, and the oxidative stress is at the highest level in lens.

Purpose: To evaluate interleukin-8 (IL-8), nitric oxide (NO) and glutathione (GSH) profiles in vitreous humor and blood samples in patients with proliferative diabetic retinopathy (PDR) and in patients with proliferative vitreoretinopathy (PVR) and to compare the levels with those of controls. Patients and Methods: NO concentrations were determined by using the Greiss reaction in plasma and vitreous humor samples. GSH levels were determined in both blood and vitreous humor samples, using DTNB, a disulfide chromogen. Vitreous IL-8 were assayed by ELISA. Twenty-three patients with PDR, 18 patients with PVR and 21 cadavers as the control group were included in the study. Results: Plasma and vitreous NO levels were found to be25.6 ± 2.1 and 36.9 ± 3.0 µmol/l in patients with PDR, 27.0 ± 4.7 and 34.3 ± 2.9 µmol/l in patients with PVR and 17.4 ± 2.7 and 15.9 ± 1.4 µmol/l in controls, respectively. Vitreous humor and plasma NO levels did not show any statistically significant difference between PDR and PVR groups. However, the values for vitreous in both groups were significantly higher than those of controls (p < 0.0001). Although IL-8 levels in vitreous samples of patients with PDR were not significantly different (79.6 ± 9.7 pg/ml) from those of patients with PVR (42.2 ± 7.3 pg/ml) (p = 0.06), the levels in both groups were significantly higher than those of controls (19.0 ± 3.9 pg/ml) (p < 0.0001 and p < 0.05, respectively). Blood and vitreousGSH levels were found to be5.3 ± 0.4 µmol/g·Hb and 0.58 ± 0.16 µmol/l in patients with PDR and 8.4 ± 0.5 µmol/g·Hb and 15.7 ± 2.2 µmol/l in patients with PVR and 12.0 ± 1.1 µmol/g·Hb and 0.26 ± 0.03 mmol/l in controls, respectively. Vitreous and blood GSH levels were significantly lower in patients with PDR compared to those with PVR (p < 0.0001 for both). Conclusion: Elevated levels of vitreous and plasma NO and vitreous IL-8 in PDR and PVR implicate a role for these parameters in the proliferation in these ocular disorders. GSH concentrations both in vitreous and blood samples of the PVR and PDR patients were much less than those observed in the control group. Lower GSH concentrations detected in PDR in comparison with those in PVR in vitreous humor and to a lesser degree in blood may play an important role in pathogenesis of new retinal vessel formation in patients with PDR. This also suggests that oxidative stress may be involved in the pathogenesis of PVR and particularly that of PDR.

No abstract

Hypertension is an important health problem throughout the world and a risk factor for many diseases. Angiotensin-converting enzyme (ACE), a component of the renin-angiotensin system, has an important role in the regulation of blood pressure. Zinc (Zn), a trace element with important biological functions, is located in the catalytic site of ACE. Calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K) also appear to be involved in hypertension pathogenesis. In this study, plasma ACE activities and Cat, Cai, Mg, Na, K, and plasma/erythrocyte Zn levels of 20 untreated patients with essential hypertension and 28 healthy individuals were evaluated. Plasma ACE activities (p<0.05) and erythrocyte Zn concentrations (p<0.001) were significantly higher in patients with essential hypertension than values of the control group. No significant difference was found between plasma Zn concentrations of the groups (p>0.05). Plasma Cat (p<0.001) and Mg levels (p<0.05) in essential hypertension were significantly lower than those of controls. Plasma Na, K, and Cai levels remained normal in essential hypertension. There are complex associations between metals and arterial pressure. Ca and Mg deficiencies seem to be associated with increased prevalence of hypertension. Increases in erythrocyte Zn may have a future potential use for diagnosis of hypertension.