Summary Since 2006, several longitudinal studies have assessed environmental or behavioural factors that seem to modify the risk of developing Parkinson's disease. Increased risk of Parkinson's ...disease has been associated with exposure to pesticides, consumption of dairy products, history of melanoma, and traumatic brain injury, whereas a reduced risk has been reported in association with smoking, caffeine consumption, higher serum urate concentrations, physical activity, and use of ibuprofen and other common medications. Randomised trials are investigating the possibility that some of the negative risk factors might be neuroprotective and thus beneficial in individuals with early Parkinson's disease, particularly with respect to smoking (nicotine), caffeine, and urate. In the future, it might be possible to identify Parkinson's disease in its prodromal phase and to promote neuroprotective interventions before the onset of motor symptoms. At this time, however, the only intervention that seems justifiable for the primary prevention of Parkinson's disease is the promotion of physical activity, which is likely to be beneficial for the prevention of several chronic diseases.
Oxidative stress has been implicated as a core contributor to the initiation and progression of multiple neurological diseases. Genetic and environmental factors can produce oxidative stress through ...mitochondrial dysfunction leading to the degeneration of dopaminergic and other neurons underlying Parkinson disease (PD). Although clinical trials of antioxidants have thus far failed to demonstrate slowed progression of PD, oxidative stress remains a compelling target. Rather than prompting abandonment of antioxidant strategies, these failures have raised the bar for justifying drug and dosing selections and for improving study designs to test for disease modification by antioxidants. Urate, the main antioxidant found in plasma as well as the end product of purine metabolism in humans, has emerged as a promising potential neuroprotectant with advantages that distinguish it from previously tested antioxidant agents. Uniquely, higher urate levels in plasma or cerebrospinal fluid (CSF) have been linked to both a lower risk of developing PD and to a slower rate of its subsequent progression in numerous large prospective epidemiological and clinical cohorts. Laboratory evidence that urate confers neuroprotection in cellular and animal models of PD, possibly via the Nrf2 antioxidant response pathway, further strengthened its candidacy for rapid clinical translation. An early phase trial of the urate precursor inosine demonstrated its capacity to safely produce well tolerated, long-term elevation of plasma and CSF urate in early PD, supporting a phase 3 trial now underway to determine whether oral inosine dosed to elevate urate to concentrations predictive of favorable prognosis in PD slows clinical decline in people with recently diagnosed, dopamine transporter-deficient PD.
Neuroinflammation may contribute to the pathogenesis of Parkinson disease (PD). Use of nonsteroidal anti-inflammatory drugs (NSAID) in general, and possibly ibuprofen in particular, has been shown to ...be related to lower PD risk in previous epidemiologic studies.
We prospectively examined whether use of ibuprofen or other NSAIDs is associated with lower PD risk among 136,197 participants in the Nurses' Health Study (NHS) and the Health Professionals Follow-up Study (HPFS) free of PD at baseline (1998 for NHS and 2000 for HPFS). NSAIDs use was assessed via questionnaire. Results were combined in a meta-analysis with those of published prospective investigations.
We identified 291 incident PD cases during 6 years of follow-up. Users of ibuprofen had a significantly lower PD risk than nonusers (relative risk RR, adjusted for age, smoking, caffeine, and other covariates = 0.62; 95% confidence interval CI 0.42-0.93; p = 0.02). There was a dose-response relationship between tablets of ibuprofen taken per week and PD risk (p trend = 0.01). In contrast, PD risk was not significantly related to use of aspirin (RR = 0.99; 95% CI 0.78-1.26), other NSAIDs (RR = 1.26; 95% CI 0.86-1.84), or acetaminophen (RR = 0.86; 95% CI 0.62-1.18). Similar results were obtained in the meta-analyses: the pooled RR was 0.73 (95% CI 0.63-0.85; p < 0.0001) for ibuprofen use, whereas use of other types of analgesics was not associated with lower PD risk.
The association between use of ibuprofen and lower PD risks, not shared by other NSAIDs or acetaminophen, suggests ibuprofen should be further investigated as a potential neuroprotective agent against PD.
Urate is a naturally occurring antioxidant whose levels are associated with reduced risk of developing Parkinson’s disease (PD) and Alzheimer’s disease. Urate levels are also associated with ...favorable progression in PD, amyotrophic lateral sclerosis, Huntington’s disease, and multisystem atrophy. These epidemiological data are consistent with laboratory studies showing that urate exhibits neuroprotective effects by virtue of its antioxidant properties in several preclinical models. This body of evidence supports the hypothesis that urate may represent a shared pathophysiologic mechanism across neurodegenerative diseases. Most importantly, beyond its role as a molecular predictor of disease risk and progression, urate may constitute a novel therapeutic target. Indeed, clinical trials of urate elevation in PD and amyotrophic lateral sclerosis are testing the impact of raising peripheral urate levels on disease outcomes. These studies will contribute to unraveling the neuroprotective potential of urate in human pathology. In parallel, preclinical experiments are deepening our understanding of the molecular pathways that underpin urate’s activities. Altogether, these efforts will bring about new insights into the translational potential of urate, its determinants, and its targets and their relevance to neurodegeneration.
OBJECTIVE:To examine whether higher plasma urate concentrations are associated with a lower risk of developing Parkinson disease (PD) and whether there is a sex difference in the potential urate–PD ...relationship.
METHODS:We conducted a nested case-control study based on 90,214 participants of 3 ongoing US cohorts. We identified 388 new PD cases (202 men and 186 women) since blood collection, which were then matched to 1,267 controls. PD cases were confirmed by medical record review. Conditional logistic regression estimated relative risks (RRs) and 95% confidence intervals (95% CIs), after adjustment for age, smoking, caffeine intake, plasma concentrations of cholesterol and ferritin, and other covariates. We also conducted a meta-analysis to combine our study with 3 previously published prospective studies on urate and PD risk.
RESULTS:In the present nested case-control study, the multivariate-adjusted RRs of PD comparing extreme quartiles of urate were 0.63 (95% CI 0.35, 1.10; ptrend = 0.049) in men and 1.04 (95% CI 0.61, 1.78; ptrend = 0.44) in women (pheterogeneity = 0.001). In the meta-analysis, the pooled RRs comparing 2 extreme quartiles of urate were 0.63 (95% CI 0.42, 0.95) in men and 0.89 (95% CI 0.57, 1.40) in women.
CONCLUSION:We observed that men, but not women, with higher urate concentrations had a lower future risk of developing PD, suggesting that urate could be protective against PD risk or could slow disease progression during the preclinical stage of disease.
Objective
Prior studies on the gut microbiome in Parkinson's disease (PD) have yielded conflicting results, and few studies have focused on prodromal (premotor) PD or used shotgun metagenomic ...profiling to assess microbial functional potential. We conducted a nested case–control study within 2 large epidemiological cohorts to examine the role of the gut microbiome in PD.
Methods
We profiled the fecal metagenomes of 420 participants in the Nurses' Health Study and the Health Professionals Follow‐up Study with recent onset PD (N = 75), with features of prodromal PD (N = 101), controls with constipation (N = 113), and healthy controls (N = 131) to identify microbial taxonomic and functional features associated with PD and features suggestive of prodromal PD. Omnibus and feature‐wise analyses identified bacterial species and pathways associated with prodromal and recently onset PD.
Results
We observed depletion of several strict anaerobes associated with reduced inflammation among participants with PD or features of prodromal PD. A microbiome‐based classifier had moderate accuracy (area under the curve AUC = 0.76 for species and 0.74 for pathways) to discriminate between recently onset PD cases and controls. These taxonomic shifts corresponded with functional shifts indicative of carbohydrate source preference. Similar, but less marked, changes were observed in participants with features of prodromal PD, in both microbial features and functions.
Interpretation
PD and features of prodromal PD were associated with similar changes in the gut microbiome. These findings suggest that changes in the microbiome could represent novel biomarkers for the earliest phases of PD. ANN NEUROL 2023;94:486–501
Despite many clinical trials over the last three decades, the goal of demonstrating that a treatment slows the progression of Parkinson’s disease (PD) remains elusive. Research advances have shed new ...insight into cellular pathways contributing to PD pathogenesis and offer increasingly compelling therapeutic targets. Here we review recent and ongoing clinical trials employing novel strategies toward disease modification, including those targeting alpha-synuclein and those repurposing drugs approved for other indications. Active and passive immunotherapy approaches are being studied with the goal to modify the spread of alpha-synuclein pathology in the brain. Classes of currently available drugs that have been proposed to have potential disease-modifying effects for PD include calcium channel blockers, antioxidants, anti-inflammatory agents, iron-chelating agents, glucagon-like peptide 1 agonists, and cAbl tyrosine kinase inhibitors. The mechanistic diversity of these treatments offers hope, but to date, results from these trials have been disappointing. Nevertheless, they provide useful lessons in guiding future therapeutic development.
Exercise may be the most commonly offered yet least consistently followed therapeutic advice for people with Parkinson's disease (PD). Epidemiological studies of prospectively followed cohorts have ...shown a lower risk for later developing PD in healthy people who report moderate to high levels of physical activity, and slower rates of motor and non-motor symptom progression in people with PD who report higher baseline physical activity. In animal models of PD, exercise can reduce inflammation, decrease α-synuclein expression, reduce mitochondrial dysfunction, and increase neurotrophic growth factor expression. Randomized controlled trials of exercise in PD have provided clear evidence for short-term benefits on many PD measurements scales, ranging from disease severity to quality of life. In this review, we present these convergent epidemiological and laboratory data with particular attention to translationally relevant features of exercise (e.g., intensity requirements, gender differences, and associated biomarkers). In the context of these findings we will discuss clinical trial experience, design challenges, and emerging opportunities for determining whether exercise can prevent PD or slow its long-term progression.
Sirtuin deacetylases regulate diverse cellular pathways and influence disease processes. Our previous studies identified the brain-enriched sirtuin-2 (SIRT2) deacetylase as a potential drug target to ...counteract neurodegeneration. In the present study, we characterize SIRT2 inhibition activity of the brain-permeable compound AK7 and examine the efficacy of this small molecule in models of Parkinson's disease, amyotrophic lateral sclerosis and cerebral ischemia. Our results demonstrate that AK7 is neuroprotective in models of Parkinson's disease; it ameliorates alpha-synuclein toxicity in vitro and prevents 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopamine depletion and dopaminergic neuron loss in vivo. The compound does not show beneficial effects in mouse models of amyotrophic lateral sclerosis and cerebral ischemia. These findings underscore the specificity of protective effects observed here in models of Parkinson's disease, and previously in Huntington's disease, and support the development of SIRT2 inhibitors as potential therapeutics for the two neurodegenerative diseases.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
