Myeloperoxidase and Advanced Oxidation Protein Products in the Cerebrospinal Fluid in Women and Men with Parkinson's Disease.

Background: Myeloperoxidase (MPO) and advanced oxidation protein products, or AOPP (a type of MPO-derived chlorinated adducts), have been implicated in Parkinson´s disease (PD). Human MPO also show sex-based differences in PD. The objective was to study the relationship of MPO and AOPP in the cerebrospinal fluid (CSF) with motor features of idiopathic PD in male and female patients. Methods: MPO concentration and activity and AOPP content were measured in the CSF and serum in 34 patients and 30 controls. CSF leukocytes and the integrity of the blood-brain barrier were evaluated. Correlations of MPO and AOPP with clinical variables were examined. Results: The blood-brain barrier was intact and CSF leukocyte count was normal in all patients. CSF MPO concentration and activity were similar in the cohort of patients and controls, but CSF MPO content was significantly higher in male patients than in PD women (p = 0.0084). CSF MPO concentration correlated with disease duration in male and female patients (p < 0.01). CSF MPO concentration was significantly higher in men with disease duration ≥12 years versus the remainder of the male subjects (p < 0.01). Changes in CSF MPO in women were not significant. Serum MPO concentration and activity were significantly higher in all PD patients relative to controls (p < 0.0001). CSF MPO was not correlated with serum MPO. Serum AOPP were detected in all patients, but CSF AOPP was undetectable in 53% of patients. AOPP were not quantifiable in controls. Conclusions: CSF MPO is not a good biomarker for PD because mean CSF MPO concentration and activity are not different between the cohort of patients and controls. CSF MPO concentration positively correlated with disease duration in men and women, but CSF MPO is significantly enhanced only in male patients with disease duration longer than 12 years. It can be hypothesized that the MPO-related immune response in early-stage PD might be weak in all patients, but then the MPO-related immune response is progressively enhanced in men, not women. Since the blood-brain barrier is intact, and CSF MPO is not correlated with serum MPO, CSF myeloperoxidase would reflect MPO content in brain cells, not blood-derived cells. Finally, serum AOPP was detected in all patients, but not controls, which is consistent with the occurrence of chlorinative stress in blood serum in PD. The study of CSF AOPP as biomarker could not be assessed because the ELISA assay was hampered by its detection limit in the CSF.

Cerebrospinal fluid lactoperoxidase level is enhanced in idiopathic Parkinson's disease, and correlates with levodopa equivalent daily dose.

Lactoperoxidase (LPO) is proposed to play a role in the pathogenesis of Parkinson's disease (PD). This enzyme has been reported to be enhanced in the cerebrospinal fluid (CSF) in parkinsonian patients. The objective was to look at the relationship of LPO in the CSF and serum with clinical features of idiopathic PD. LPO concentration was analyzed through ELISA techniques. Correlation of CSF or serum LPO and MDS-UPDRS, dopaminergic medication, and other clinical parameters was examined. The findings revealed that LPO concentration in the CSF, not serum, was found to be elevated in patients with PD relative to controls (p < 0.001). CSF LPO concentration negatively correlated with MDS-UPDRS part-IV score (p < .0001), a rating scale that allows evaluating motor complications. CSF LPO level inversely correlated with the dose intensity of the dopaminergic medication regimen, as evaluated with levodopa equivalent dose or LED (mg/day; p < .0001). LED value positively correlated with MDS-UPDRS part-IV score (p < .0001). To sum up, the findings indicate that CSF LPO is found to be elevated in the CSF of PD patients, and this enzyme holds promise as potential biomarker for diagnosis of PD. Increasing the dose intensity of the dopaminergic medication regimen attenuates the elevation in LPO levels in the CSF, and it facilitates the development of motor complications in patients. The pathophysiological mechanisms that seem to be responsible for LPO increase would include dopamine deficiency, oxidative stress, and less likely, microbial infection.

Analysis of neurotrophic and antioxidant factors related to midbrain dopamine neuronal loss and brain inflammation in the cerebrospinal fluid of the elderly.

Midbrain dopamine neuronal loss and neuroinflammation are two phenomena that are associated with brain senescence. Neurotrophic factor changes and oxidative stress could subserve these phenomena. Aging-related brain changes can be well monitored through the cerebrospinal fluid (CSF). The objective was to analyze neurotrophic and oxidative parameters that could be related to midbrain dopamine neuronal loss or brain inflammation in the CSF of elderly subjects: 1) levels of the dopaminotrophic factors BDNF, GDNF, persephin, and neurturin, 2) levels of the proinflammatory factors TGFß1 and TGFß2; 3) activity of main antioxidant enzymes (catalases, glutathione-peroxidase, glutathione-reductase, glutathione-S-transferases, peroxirredoxins, and superoxide-dismutases), 4) ferritin content, antioxidant protein which reduces reactive free iron, and 5) antioxidant potential of the cerebrospinal fluid. ELISA and PAO tests were used. Subjects were also evaluated clinically, and the group of old subjects with mild cognitive impairment was studied separately. The findings indicate that normal elderly CSF is devoid of changes in either dopaminotrophic or proinflammatory factors. The antioxidant efficacy is slightly reduced with normal aging, through a reduction of glutathione-S-transferase activity in people older than 74 years (p < 0.05). However old people with mild cognitive impairment show reduced BDNF levels, and stronger signs of oxidative stress such as low antioxidant potential and glutathione-S-transferase activity (p < 0.05). To sum up, the present study demonstrates that, in CSF of normal senescence, dopaminotrophic factors and proinflammatory TGF-family ligands are not affected, and antioxidant efficacy is slightly reduced. CSF of elderly subjects with mild cognitive impairment shows more oxidative and trophic changes that are characterized by reduction of BDNF content, glutathione-S-transferase activity, and antioxidant potential.

Does the Cerebrospinal Fluid Reflect Altered Redox State But Not Neurotrophic Support Loss in Parkinson's Disease?

Alteration in neurotrophic factors support and antioxidant defenses in the central nervous system (CNS) along with deficit of ferritin have been associated with idiopathic Parkinson's disease (PD). The objectives were to analyze in the cerebrospinal fluid (CSF) of patients with PD and controls the following: (i) the levels of the neuroprotectant factors glial cell line-derived neurotrophic factor, persephin, neurturin, and brain-derived neurotrophic factor, (ii) the levels of transforming growth factor-ß1 (TGFß1) and transforming growth factor-ß2 (TGFß2), proinflammatory factors, (iii) the activity of the antioxidant enzymes glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST), catalase, superoxide dismutases (SODs), and peroxiredoxins (PRDxs), and (iv) ferritin levels. The study revealed that, among neurotrophic factors, only TGFß1 levels were found to be enhanced in patients with PD (early, p < 0.05; advanced, p < 0.02). Regarding antioxidant enzymes, the activity of GPx, catalase, and PRDxs, all hydrogen peroxide scavengers, was found to be significantly reduced in patients (GPx, p < 0.001; catalase, p < 0.01; PRDxs, p < 0.01, one-way analysis of variance). Finally, ferritin content in CSF was significantly diminished over time in patients (early, p < 0.01, -49%; advanced, p < 0.001, -80.7%). Our observations lead to the hypothesis that parkinsonian patients suffer from a serious disturbance of redox state in the CNS, as evaluated through the CSF, characterized by reduced hydrogen peroxide scavenging and iron storage.

May the thyroid gland and thyroperoxidase participate in nitrosylation of serum proteins and sporadic Parkinson's disease?

The research group has detected nitrosative stress and a singular version of nitrosylated serum α-synuclein in serum of Parkinson's disease (PD) patients. Dysfunction of the thyroid gland has been proposed to be linked to this disease. The aim of the study was to know if the thyroid gland is involved in idiopathic PD and nitrosative stress. We studied 50 patients (early and advanced disease patients), 35 controls, and 6 subjects with thyroidectomy. Clinical characteristics, serum thyroperoxidase levels, and 3-nitrotyrosine proteins were analyzed. Enzyme-linked immunosorbent assay and immunoblotting methods were employed. The findings indicated that the prevalence of two thyroid dysfunctions (hyper- or hypothyroidism) was not found to be different in patients relative to controls. However, the levels of the enzyme thyroperoxidase were found to be elevated in early disease patients (p<0.006), not in advanced disease subjects, and these levels were negatively correlated with serum 3-nitrotyrosine proteins (p<0.05), the indicators of nitrosative stress. The thyroidectomized subjects showed very low levels of serum 3-nitrotyrosine proteins (78% reduction vs. controls) and, among these proteins, the nitrosylated serum α-synuclein was nearly absent. These observations lead to the hypothesis that the thyroid gland and thyroperoxidase participate in nitrosylation of serum proteins and they could influence Parkinsonian nitrosative stress as well as nitrosylation of serum α-synuclein, a potentially pathogenic factor.

May the evaluation of nitrosative stress through selective increase of 3-nitrotyrosine proteins other than nitroalbumin and dominant tyrosine-125/136 nitrosylation of serum α-synuclein serve for diagnosis of sporadic Parkinson's disease?

Nitrosative stress, where nitrosylation of tyrosine (Tyr) leading to 3-nitrotyrosine proteins or free 3-nitrotyrosine is the most prominent change, has been proposed as a pathogenic mechanism in Parkinson's disease (PD). Levels of 3-nitrotyrosine proteins in serum and cerebrospinal fluid (CSF) of patients with PD have not been studied. Nitrosative stress-induced protein changes in serum and CSF were analyzed in patients with PD (n=54) and controls (n=40). Herein, we demonstrate the presence of nitrosative stress in serum and CSF of patients with early PD leading to selective increase of 3-nitrotyrosine proteins other than nitroalbumin, without free 3-nitrotyrosine (Hoehn-Yahr stage 1, p<0.05; stage 2, p<0.01). Among 3-nitrotyrosine proteins, nitro-α-synuclein (N-αSyn) was detected in serum, not CSF, and the sites of Tyr nitrosylation were observed to be modified in patients with early PD. Thus, the intensity of nitrosylation of Tyr125/136 residues is enhanced (stage 1, p<0.05; stage 2, p<0.01), and that of the Tyr39 site is reduced (stage 1, p<0.05), and the ratio between both parameters (α-synuclein with nitrosylated tyrosines 125 and 136 [N-αSyn-Tyr125/136]:α-synuclein with nitrosylated tyrosine 39 [N-αSyn-Tyr39] ratio) is significantly higher in patients with early PD (p<0.01). These observations lead to the hypothesis that evaluating nitrosative stress through enhanced levels of 3-nitrotyrosine proteins in serum and CSF without changes in nitroalbumin, together with the profile of tyrosine nitrosylation of serum αSyn characterized by dominant nitrosylation of Tyr125/136, could serve for the diagnosis of sporadic PD.

May serum levels of advanced oxidized protein products serve as a prognostic marker of disease duration in patients with idiopathic Parkinson's disease?

Protein and amine halogenation is a type of oxidative stress induced by phagocytic overstimulation, and its role in Parkinson's disease (PD) has not been discerned. We have detected that advanced oxidized protein products, markers of protein halogenation, are reliably enhanced in serum of patients with PD (n=60) relative to control subjects (n=45, p<0.012), and to a lesser extent in the cerebrospinal fluid. Amine halogenation, as evaluated through 3-chlorotyrosine, is not affected. Mieloperoxidase and hydrogen peroxide levels, halogenative factors of phagocytes, are devoid of changes. Levels of advanced oxidized protein products are progressively reduced over time, and the duration of PD is larger in the Hoehn-Yahr-stage-2/3 patients (n=34) with low serum levels (R(2)=0.0145, p<0.003). Levodopa treatment contributes to this reduction (R(2)=0.259, p<0.001). These protein products are not cytotoxic, unlike 3-chlorotyrosine, but they are known to form inflammatory mediators after conjugation with serum albumin. Our observations lead to the hypothesis that the serum level of advanced oxidized protein products is a prognostic marker of PD duration, and these oxidized proteins could participate in the development of parkinsonian neurodegeneration.