RESUMEN
Background: Cardiovascular disease is the major cause of mortality in patients undergoing chronic hemodialysis treatment. The oxidative modification of low-density lipoprotein is a crucial step in the pathogenesis of atherosclerosis. Paraoxonase 1 (PON1) is the protein responsible for most of the antioxidant activity of high-density lipoprotein, and its reduced levels are associated with more cardiovascular events in several populations. In hemodialysis patients, reduced PON1 activity has been shown to be associated with increased cardiovascular mortality. Studies have shown that after the hemodialysis session, the activity of PON1 increases. The influence of dialyzer reuse on the activity of PON1 is unknown. We aimed to evaluate the effect of the reuse of two types of dialyzers (polynephron and polyethersulfone) on the PON1 activity of hemodialysis patients. Subjects and Methods: A total of 30 patients on hemodialysis were included. Pre- and post-dialysis blood samples were collected to analyze the activity of PON1 in thefirst use of the dialyzer and in the hemodialysis session of its sixth reuse. This process was carried out with polynephron (bisphenol-free) and polyethersulfone dialyzers. Results: We found that post-dialysis PON1 activity was significantly higher than pre-dialysis activity in both thefirst use and sixth reuse (P < 0.001). Conclusion: The practice of reusing the dialyzer did not interfere with the improvement of PON1 activity after the hemodialysis session.
RESUMEN
BACKGROUND: Primary deficit schizophrenia (DS) is characterized by enduring negative symptoms and represents a qualitatively different disease entity with respect to non-deficit schizophrenia (NDS). No studies investigated the association between the enzyme paraoxonase 1 (PON1) and DS and its phenomenology. METHODS: In this case-control study, Thai women and men, aged 18 to 65 years, were divided in DS (n = 40) and NDS (n = 40) and were compared to controls (n = 40). PON1 activities against 4-(chloromethyl)phenyl acetate (CMPA) and phenylacetate were determined. Moreover, subjects were genotyped for their PON1 Q192R polymorphism and immunoglobulin A (IgA) levels responses directed to Gram-negative bacteria were measured. RESULTS: DS is significantly associated with the QQ genotype and the Q allele as compared with NDS and controls. PON1 activities are significantly and inversely associated with negative symptoms, formal thought disorders, psychomotor retardation, excitation and DS. The presence of the Q allele is associated with increased IgA responses to Pseudomonas aeruginosa, Morganella morganii, and Pseudomonas putida as compared with RR carriers. CONCLUSIONS: The PON1 Q allele and lower PON1 activities especially against CMPA are associated with DS, indicating lowered quorum quenching abilities as well as lowered defenses against lipoperoxidation and immune activation. It is suggested that lowered PON1 activity in DS constitutes an impairment in the innate immune system which together with lowered natural IgM may cause lower immune regulation thereby predisposing toward greater neurotoxic effects of immune-inflammatory, oxidative and nitrosative pathways and Gram-negative microbiota.