There is evidence that immune-inflammatory, stress of reactive oxygen and nitrogen species (IO&NS) processes play a role in the neurodegenerative processes observed in Parkinson's disease (PD). The aim of the present study was to investigate peripheral IO&NS biomarkers in PD. We included 56 healthy individuals and 56 PD patients divided in two groups: early PD stage and late PD stage. Plasma lipid hydroperoxides (LOOH), malondialdehyde (MDA), nitric oxide metabolites (NOx), sulfhydryl (SH) groups, catalase (CAT) activity, superoxide dismutase (SOD) activity, paraoxonase (PON)1 activity, total radical trapping antioxidant parameter (TRAP) and C-reactive protein (CRP) were measured. PD is characterized by increased LOOH, MDA and SOD activity and lowered CAT activity. A combination of five O&NS biomarkers highly significantly predicts PD with a sensitivity of 94.5% and a specificity of 86.8% (i.e., MDA, SOD activity, TRAP, SH-groups and CAT activity). The single best biomarker of PD is MDA, while LOOH and SOD activity are significantly associated with late PD stage, but not early PD stage. Antiparkinson drugs did not affect O&NS biomarkers, but levodopa+carbidopa significantly increased CRP. It is suggested that MDA may serve as a disease biomarker, while LOOH and SOD activity are associated with late PD stage characteristic. New treatments for PD should not only target dopamine but also lipid peroxidation.
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.
Pregnancy is accompanied by interrelated signs of O&NS, lowered antioxidant defenses and activated neuro-immune pathways. Increased O&NS at the end of term is associated with perinatal depressive and physio-somatic symptoms and may predict obstetric and behavioral complications in mother and baby.
Lowered levels of IgM responses to MDA during pregnancy are accompanied by a reduced regulation of nitro-oxidative processes thereby explaining increased oxidative and nitrosative stress biomarkers in association with DPSS. IgM responses to NO adducts, which reflect nitrosylation as a consequence of increased NO production, regulate DPSS symptoms at the end of term and are a trait marker of major depression. IgM responses to MDA are a key part of the compensatory anti-inflammatory responses system.
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