Association of Polyunsaturated Fatty Acids and Clinical Progression in Patients With ALS: Post Hoc Analysis of the EMPOWER Trial.

BACKGROUND AND OBJECTIVES: Polyunsaturated fatty acids (PUFAs) have neuroprotective and anti-inflammatory effects and could be beneficial in amyotrophic lateral sclerosis (ALS). Higher dietary intake and plasma levels of PUFAs, in particular alpha-linolenic acid (ALA), have been associated with a lower risk of ALS in large epidemiologic cohort studies, but data on disease progression in patients with ALS are sparse. We examined whether plasma levels of ALA and other PUFAs contributed to predicting survival time and functional decline in patients with ALS. METHODS: We conducted a study among participants in the EMPOWER clinical trial who had plasma samples collected at the time of randomization that were available for fatty acid analyses. Plasma fatty acids were measured using gas chromatography. We used Cox proportional hazards models and linear regression to evaluate the association of individual fatty acids with risk of death and joint rank test score of functional decline and survival. RESULTS: Fatty acid analyses were conducted in 449 participants. The mean (SD) age of these participants at baseline was 57.5 (10.7) years, and 293 (65.3%) were men; 126 (28.1%) died during follow-up. Higher ALA levels were associated with lower risk of death (age-adjusted and sex-adjusted hazard ratio comparing highest vs lowest quartile 0.50, 95% CI 0.29-0.86, p-trend = 0.041) and higher joint rank test score (difference in score according to 1 SD increase 10.7, 95% CI 0.2-21.1, p = 0.045), consistent with a slower functional decline. The estimates remained similar in analyses adjusted for body mass index, race/ethnicity, symptom duration, site of onset, riluzole use, family history of ALS, predicted upright slow vital capacity, and treatment group. Higher levels of the n-3 fatty acid eicosapentaenoic acid and the n-6 fatty acid linoleic acid were associated with a lower risk of death during follow-up. DISCUSSION: Higher levels of ALA were associated with longer survival and slower functional decline in patients with ALS. These results suggest that ALA may have a favorable effect on disease progression in patients with ALS.

Long-Term Intake of Folate, Vitamin B6, and Vitamin B12 and the Incidence of Parkinson's Disease in a Sample of U.S. Women and Men.

BACKGROUND: Folate and vitamins B6 and B12 have been proposed as protective against the development of Parkinson's disease (PD). Two prior longitudinal studies were inconclusive. OBJECTIVE: The aim was to examine the association of long-term intake of folate, vitamin B6, and vitamin B12 with the incidence of PD. METHODS: The study population comprised 80,965 women (Nurses' Health Study, 1984-2016) and 48,837 men (Health Professionals Follow-up Study, 1986-2016) followed prospectively for the development of PD. Intake of B vitamins was measured at baseline and every 4 years thereafter using food frequency questionnaires. We estimated the hazard ratio (HR) and 95% confidence interval (CI) of PD based on quintiles of cumulative average intake adjusting for potential confounders. Secondary analyses considered different lagged exposure periods as well as baseline and recent intakes. RESULTS: In separate analyses of cumulative average intake, total folate, B6, and B12 were not associated with the risk of PD. Results from 8-, 12-, and 16-year lag analyses were consistent with these findings. Results for baseline intake of folate and B6 also pointed toward a null association. In contrast, a lower PD risk was observed among individuals with higher baseline total intake of B12 (pooled HR top vs. bottom quintile: 0.80; 95% CI: 0.67-0.95; P-trend = 0.01); results from 20-year lag analyses were consistent with this finding. CONCLUSIONS: Our results do not support the hypothesis that a higher intake of folate or vitamin B6 would reduce PD risk in this population. Our results provide moderate support for a possible protective effect of vitamin B12 on the development of PD. © 2023 International Parkinson and Movement Disorder Society.

Dissociation between urate and blood pressure in mice and in people with early Parkinson's disease.

BACKGROUND: Epidemiological, laboratory and clinical studies have established an association between elevated urate and high blood pressure (BP). However, the inference of causality remains controversial. A naturally occurring antioxidant, urate may also be neuroprotective, and urate-elevating treatment with its precursor inosine is currently under clinical development as a potential disease-modifying strategy for Parkinson's disease (PD). METHODS: Our study takes advantage of a recently completed phase II trial evaluating oral inosine in de novo non-disabling early PD with no major cardiovascular and nephrological conditions, and of three lines of genetically engineered mice: urate oxidase (UOx) global knockout (gKO), conditional KO (cKO), and transgenic (Tg) mice with markedly elevated, mildly elevated, and substantially reduced serum urate, respectively, to systematically investigate effects of urate-modifying manipulation on BP. FINDINGS: Among clinical trial participants, change in serum urate but not changes in systolic, diastolic and orthostatic BP differed by treatment group. There was no positive correlation between urate elevations and changes in systolic, diastolic and orthostatic BP ((p = .05 (in inverse direction), 0.30 and 0.63, respectively)). Between UOx gKO, cKO, or Tg mice and their respective wildtype littermates there were no significant differences in systolic or diastolic BP or in their responses to BP-regulating interventions. INTERPRETATION: Our complementary preclinical and human studies of urate modulation in animal models and in generally healthy early PD do not support a hypertensive effect of urate elevation or an association between urate and BP. FUND: U.S. Department of Defense, RJG Foundation, Michael J. Fox Foundation LEAPS program, National Institutes of Health, American Federation for Aging Research, Parkinson's Disease Foundation Advancing Parkinson's Therapies initiative.

Intake of antioxidant vitamins and risk of Parkinson's disease.

INTRODUCTION: Oxidative stress is proposed to be one of the potential mechanisms leading to neurodegeneration in Parkinson's disease. However, previous epidemiologic studies investigating associations between antioxidant vitamins, such as vitamins E and C and carotenoids, and PD risk have produced inconsistent results. OBJECTIVE: The objective of this work was to prospectively examine associations between intakes of antioxidant vitamins, including vitamins E and C and carotenoids, and PD risk. METHODS: Cases were identified in two large cohorts: the Nurses' Health Study and the Health Professionals Follow-up Study. Cohort members completed semiquantitative food frequency questionnaires every 4 years. RESULTS: A total of 1036 PD cases were identified. Dietary intakes of vitamin E and carotenoids were not associated with PD risk; the multivariable-adjusted relative risk comparing extreme intake quintiles were 0.93 (95% confidence interval: 0.75-1.14) and 0.97 (95% confidence interval: 0.69-1.37), respectively. Dietary vitamin C intake was significantly associated with reduced PD risk (relative risk: 0.81; 95% confidence interval: 0.65-1.01; ptrend , 0.01); however, this result was not significant in a 4-year lag analysis. For vitamins E and C, intake from foods and supplements combined were also unrelated to PD risk. CONCLUSIONS: Our results do not support the hypothesis that intake of antioxidant vitamins reduces the risk of PD. © 2016 International Parkinson and Movement Disorder Society.

Neuroprotective effects of urate are mediated by augmenting astrocytic glutathione synthesis and release.

Urate has emerged as a promising target for neuroprotection based on epidemiological observations, preclinical models, and early clinical trial results in multiple neurologic diseases, including Parkinson's disease (PD). This study investigates the astrocytic mechanism of urate's neuroprotective effect. Targeted biochemical screens of conditioned medium from urate- versus vehicle-treated astrocytes identified markedly elevated glutathione (GSH) concentrations as a candidate mediator of urate's astrocyte-dependent neuroprotective effects. Urate treatment also induced the nuclear translocation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) protein and transcriptional activation of its key target genes in primary astrocytic cultures. Urate's neuroprotective effect was attenuated when GSH was depleted in the conditioned media either by targeting its synthesis or release by astrocytes. Overall, these results implicate GSH as the extracellular astrocytic factor mediating the protective effect of urate in a cellular model of PD. These results also show that urate can employ a novel indirect neuroprotective mechanism via induction of the Nrf2 signaling pathway, a master regulator of the response to oxidative stress, in astrocytes.

Disrupted and transgenic urate oxidase alter urate and dopaminergic neurodegeneration.

Urate is the end product of purine metabolism in humans, owing to the evolutionary disruption of the gene encoding urate oxidase (UOx). Elevated urate can cause gout and urolithiasis and is associated with cardiovascular and other diseases. However, urate also possesses antioxidant and neuroprotective properties. Recent convergence of epidemiological and clinical data has identified urate as a predictor of both reduced risk and favorable progression of Parkinson's disease (PD). In rodents, functional UOx catalyzes urate oxidation to allantoin. We found that UOx KO mice with a constitutive mutation of the gene have increased concentrations of brain urate. By contrast, UOx transgenic (Tg) mice overexpressing the enzyme have reduced brain urate concentrations. Effects of the complementary UOx manipulations were assessed in a mouse intrastriatal 6-hydroxydopamine (6-OHDA) model of hemiparkinsonism. UOx KO mice exhibit attenuated toxic effects of 6-OHDA on nigral dopaminergic cell counts, striatal dopamine content, and rotational behavior. Conversely, Tg overexpression of UOx exacerbates these morphological, neurochemical, and functional lesions of the dopaminergic nigrostriatal pathway. Together our data support a neuroprotective role of endogenous urate in dopaminergic neurons and strengthen the rationale for developing urate-elevating strategies as potential disease-modifying therapy for PD.

Caffeine and risk of Parkinson's disease in a large cohort of men and women.

Caffeine consumption has been associated with a reduced risk of Parkinson's disease (PD). The association is strong and consistent in men, but uncertain in women, possibly because of an interaction with hormone replacement therapy (HRT). We sought to confirm these findings using data on PD incidence in the Cancer Prevention Study II Nutrition Cohort (CPS II-Nutrition), a large, prospective study of men and women. We conducted a prospective study of caffeine intake and risk of PD within the CPS II Nutrition Cohort. Intakes of coffee and other sources of caffeine were assessed at baseline. Incident cases of PD (n = 317; 197 men and 120 women) were confirmed by treating physicians and medical record review. Relative risks (RRs) were estimated using proportional hazards models, adjusting for age, smoking, and alcohol consumption. After adjustment for age, smoking, and alcohol intake, high caffeine consumption was associated with a reduced risk of PD. The RR comparing the 5th to the 1st quintile of caffeine intake was 0.43 (95% confidence interval [CI]: 0.26, 0.71; P trend = <0.002) in men, and 0.61 (95% CI: 0.34, 1.09; P trend = 0.05) in women. Among women, this association was stronger among never users of HRT (RR = 0.32) than among ever users (RR = 0.81; P interaction = 0.15). Consumption of decaffeinated coffee was not associated with PD risk. Findings from this large, prospective study of men and women are consistent with a protective effect of caffeine intake on PD incidence, with an attenuating influence of HRT in women. © 2012 Movement Disorder Society.

Recreational physical activity and risk of Parkinson's disease.

The purpose of this study was to investigate associations between recreational physical activity and Parkinson's disease (PD) risk. We prospectively followed 143,325 participants in the Cancer Prevention Study II Nutrition Cohort from 1992 to 2001 (mean age at baseline = 63). Recreational physical activity was estimated at baseline from the reported number of hours per week on average spent performing light intensity activities (walking, dancing) and moderate to vigorous intensity activities (jogging/running, lap swimming, tennis/racquetball, bicycling/stationary bike, aerobics/calisthenics). Incident cases of PD (n = 413) were confirmed by treating physicians and medical record review. Relative risks (RR) were estimated using proportional hazards models, adjusting for age, gender, smoking, and other risk factors. Risk of PD declined in the highest categories of baseline recreational activity. The RR comparing the highest category of total recreational activity (men > or = 23 metabolic equivalent task-hours/week [MET-h/wk], women > or = 18.5 MET-h/wk) to no activity was 0.8 (95% CI: 0.6, 1.2; P trend = 0.07). When light activity and moderate to vigorous activity were examined separately, only the latter was found to be associated with PD risk. The RR comparing the highest category of moderate to vigorous activity (men > or = 16 MET-h/wk, women > or = 11.5 MET-h/wk) to the lowest (0 MET-h/wk) was 0.6 (95% CI: 0.4, 1.0; P trend = 0.02). These results did not differ significantly by gender. The results were similar when we excluded cases with symptom onset in the first 4 years of follow-up. Our results may be explained either by a reduction in PD risk through moderate to vigorous activity, or by decreased baseline recreational activity due to preclinical PD.

A prospective study of night shift work, sleep duration, and risk of Parkinson's disease.

The authors prospectively investigated whether working rotating night shifts was associated with the risk of Parkinson's disease among 84,794 female nurses who reported years of night shift work in 1988 (the US Nurses' Health Study). After 975,912 person-years of follow-up (1988-2000), 181 incident Parkinson's disease cases were documented. Compared with nurses who never worked rotating night shifts, those with 15 years or more of night shift work had a 50% lower risk of Parkinson's disease after adjustment for age and smoking (95% confidence interval: 0.26, 0.97; p(trend) = 0.01). Sleep duration was positively associated with Parkinson's disease risk: The relative risk was 1.84 (95% confidence interval: 0.99, 3.42) when comparing nurses who reported 9 or more hours of sleep per day with those who slept 6 hours or less (p(trend) = 0.005). These data suggest that working night shifts may be protective against Parkinson's disease or that low tolerance for night shift work is an early marker of Parkinson's disease. Conversely, habitual longer sleep duration may be an earlier marker of Parkinson's disease. Because of the novelty and the exploratory nature of these findings, confirmation is needed.

Monoamine oxidase B inhibition and neuroprotection: studies on selective adenosine A2A receptor antagonists.

The principal therapeutic agents used in the management of Parkinson's disease (PD) enhance nigrostriatal dopaminergic flux through either replenishment of depleted dopamine stores or the action of dopaminergic agonists. Adenosine A2A receptor antagonists (e.g., KW-6002) may provide symptomatic relief in PD and perhaps also may display neuroprotective properties based on studies in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of nigrostriatal neurodegeneration. A second class of compounds that is neuroprotective in the MPTP model comprises inhibitors of the outer mitochondrial flavoenzyme monoamine oxidase B (MAO B), one of the two forms of MAO that regulate levels of brain neurotransmitter substances, including dopamine. In this article, data are presented that document the overlapping A2A antagonist and MAO B inhibitory properties of several 2-styrylxanthinyl derivatives. A limited structure-activity analysis of these compounds and structurally related analogs is provided. The results raise the possibility that a single structure may offer the combined benefits of two pharmacologic strategies, each with symptomatic and potential neuroprotective benefits, for the management of PD.