Background: Several lines of evidence, including postmortem studies, suggest increased oxidative stress and inflammation in patients with schizophrenia. Alteration of oxidative stress markers has been reported in schizoprenia studies, but with inconsistent results. Oxidized low-density lipoproteins (oxLDL) have been reported to be capable of eliciting neurocytotoxicity. On the other hand, paraoxonase (PON1), an arylesterase(ARE), plays a role in protection against oxidative modifications of LDL and is considered to be one of the antioxidant enzymes. There are no studies showing the changes in oxidative stress and inflammation together, nor the activities of PON1 and ARE in schizophrenic patients. In this study, we examined PON1, ARE activities and oxidative/anti-oxidative markers in patients with chronic schizophrenia and healthy controls. Methods: We recruited 30 male chronic schizophrenic patients and 30 male healthy control subjects and examined C-reactive protein(CRP), fibrinogen, PON1, ARE and plasma total antioxidant status (TAS) and total oxidant status (TOS), oxidative stress index(OSI) in both groups. Schizophrenia symptoms were assessed using the positive and negative syndrome scale (PANSS). The related routine lipid profile parameters including HDL were also examined. Results: Patients had significantly higher CRP, fibrinogen, TOS and OSI levels; but the patients and control subjects did not differ on activities of the antioxidant enzymes PON1 and ARE. Interestingly, there were not any group differences in the lipid profile parameters except the triglyceride levels, that increased significantly in the patient group. Conclusions: In the present study, reporting the ARE activities besides the PON1 activities in schizophrenic patients for the first time, we showed that PON1 and ARE enzyme activities were not statistically different in patients with chronic schizophrenia. This study provides additional evidence of increased oxidative stress and inflammation in chronic schizophrenia, but no alterations in the antioxidant status were observed. Our results suggest that other mechanisms than the high density lipoprotein(HDL)-disfunctionality, namely decreases in PON1 or ARE enzyme activities, are more important in oxidative or antioxidative pathophysiological processes in schizophrenia.

Increases in the generation of reactive oxygen species and decreases in antioxidant enzyme activities with aging have been reported in the prostate, and are also observed in age-related disorders such as atherosclerosis, Alzheimer's disease, and cataracts. Several studies have demonstrated that proteins are targets for reactive oxidants in cells, and that oxidized proteins accumulate during aging, oxidative stress and in some pathological conditions. However, only a limited number of studies have actually evaluated oxidative damage in relation to HDL-cholesterol-associated antioxidant enzyme activities or have assessed its relationship with prostate cancer. In this study, we examined the effect of HDL-cholesterol-associated antioxidant enzyme activities, paraoxonase1, arylesterase and new oxidative stress parameters (total oxidant status, total antioxidant status [and oxidative stress index]) in newly-diagnosed prostate cancer patients and healthy controls. There were no significant differences in oxidative stress parameters and lipid parameters between prostate cancer patients and controls, however, paraoxonase1 enzyme activity, and non-HDL-cholesterol levels were higher in prostate cancer patients than controls. The results of this study were derived from a small number of subjects, but might represent an important working hypothesis for further research in a larger number of cases to clarify the role of paraoxonase1 overproduction on the prostate and its clinical relevance.

SummaryBackgroundOxidative stress may be involved in the pathogenesis of every human disease. To understand its possible role in benign prostatic hyperplasia (BPH), we measured the overall oxidative status of patients with BPH and the serum activity of the high density lipoprotein (HDL)-related antioxidant enzymes paraoxonase 1 (PON1) and arylesterase (ARE).MethodsFifty-six urology outpatient clinic patients with BPH (mean age 64±8.6 years) were prospectively included in the study. Forty volunteer healthy controls from the laboratory staff (mean age 62±10 years) were enrolled for comparison. Serum total antioxidant status (TAS), total oxidant status (TOS), PON1, ARE, and HDL levels were measured by commercially available, ready-to-use kits.ResultsSerum TAS and HDL levels were significantly lower in the BPH group than in the control group (P=0.004 and P=0.02, respectively). No significant between-group differences were observed for TOS levels or PON1 and ARE enzyme activities (P=0.30, P=0.89, and P=0.74, respectively). In the BPH group, the calculated parameters PON1/HDL and ARE/HDL were significantly higher (P=0.02 and P=0.04, respectively).ConclusionsOur findings agree with the previous reports of impaired oxidant/antioxidant balance in BPH patients. The activities of HDL-related enzymes between groups with significantly different HDL levels may be deceptive; adjusted values may help to reach more accurate conclusions.