Simvastatin Inhibited the Apoptosis of PC12 Cells Induced by 1-Methyl-4-Phenylpyridinium Ion via Inhibiting Reactive Oxygen Species Production

Association between Statin Use and Risk of Parkinson’s Disease: Evidence from 18 Observational Studies Comprising 3.7 Million Individuals

The potential impact of statins on the risk of Parkinson’s disease (PD) is still controversial; therefore, we conducted a comprehensive meta-analysis of observational studies to examine the effect of statin use on the risk of PD. We searched electronic databases, such as PubMed, EMBASE, Scopus, and Web of Science, for articles published between 1 January 2000 and 15 March 2022. Cohort studies which examined the association between statins and PD risk in the general population were also included. Two authors assessed the data and extracted all potential information for analysis. Random effects meta-analyses were performed to measure the risk ratio (RR) and 95% confidence intervals (CIs). Eighteen cohort studies including 3.7 million individuals with 31,153 PD participants were identified. In statin users, compared with non-users, the RR for PD was 0.79 (95% CI: 0.68–0.91). In a subgroup analysis of PD, this association was observed with medium and high quality, and the studies were adjusted for age, gender, and smoking status. When the data were stratified according to the duration of exposure, long-duration statin use was associated with a decreased risk of PD (RR = 0.49; 95% CI: 0.26–0.92). There was no significant decrease in the risk of PD in short-term statin users (RR = 0.94; 95% CI: 0.67–1.31). Moreover, no significant difference in the reduction in the risk of PD was observed between men (RR = 0.80; 95% CI: 0.75–0.86) and women (RR = 0.80; 95% CI: 0.75–0.86). Although our findings confirm a reduction in the PD risk associated with statin treatment and suggest that statins play a clinically favorable role, these findings should be interpreted with caution. Future randomized control trials with an ad hoc design are needed to confirm the potential utility of statins in reducing the risk of PD.

Association between statin use and Parkinson's disease in Korean patients with hyperlipidemia

INTRODUCTION

Findings on the association between statin therapy and Parkinson's disease (PD) occurrence have been inconsistent. This study aimed to identify the association between statin use and PD in participants with a history of hyperlipidemia or blood cholesterol >200 in a Korean population to exclude nonstatin users owing to normal lipid values.

METHODS

We conducted a nested case-control analysis using the Korean National Health Insurance Service-National Sample Cohort assessed between 2002 and 2015. We identified 3026 PD cases. A total of 12,104 controls were then individually matched by age, sex, income, and region of residence at a ratio of 1:4. Potential confounders comprised basic demographic factors, lifestyle factors, various medical conditions and comorbidities. A conditional/unconditional logistic regression method was applied.

RESULTS

Compared with statin use for <6 months, adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for 6-12 months of statin use and ≥12 months of statin use were 1.03 (0.92-1.15) and 1.61 (1.35-1.93) after adjustment for confounders, respectively (P = 0.664 and P < 0.001). In analyses according to statin solubility, only the association between lipophilic statin use for ≥12 months and PD maintained statistical significance, with an aOR of 1.64 (95% CI = 1.34-2.01, P < 0.001). These relations were consistent in subgroup analyses by covariates.

CONCLUSIONS

Statin use for more than 12 months was associated with a higher probability of PD in the Korean population with hyperlipidemia. This probability was significant for lipophilic statins but not hydrophilic statins.

The History, Status, Gaps, and Future Directions of Neurotoxicology in China

BACKGROUND

Rapid economic development in China has produced serious ecological, environmental, and health problems. Neurotoxicity has been recognized as a major public health problem. The Chinese government, research institutes, and scientists conducted extensive studies concerning the source, characteristics, and mechanisms of neurotoxicants.

OBJECTIVES

This paper presents, for the first time, a comprehensive history and review of major sources of neurotoxicants, national bodies/legislation engaged, and major neurotoxicology research in China.

METHODS

Peer-reviewed research and pollution studies by Chinese scientists from 1991 to 2015 were examined. PubMed, Web of Science and Chinese National Knowledge Infrastructure (CNKI) were the major search tools.

RESULTS

The central problem is an increased exposure to neurotoxicants from air and water, food contamination, e-waste recycling, and manufacturing of household products. China formulated an institutional framework and standards system for management of major neurotoxicants. Basic and applied research was initiated, and international cooperation was achieved. The annual number of peer-reviewed neurotoxicology papers from Chinese authors increased almost 30-fold since 2001.

CONCLUSIONS

Despite extensive efforts, neurotoxicity remains a significant public health problem. This provides great challenges and opportunities. We identified 10 significant areas that require major educational, environmental, governmental, and research efforts, as well as attention to public awareness. For example, there is a need to increase efforts to utilize new in vivo and in vitro models, determine the potential neurotoxicity and mechanisms involved in newly emerging pollutants, and examine the effects and mechanisms of mixtures. In the future, we anticipate working with scientists worldwide to accomplish these goals and eliminate, prevent and treat neurotoxicity.

CITATION

Cai T, Luo W, Ruan D, Wu YJ, Fox DA, Chen J. 2016. The history, status, gaps, and future directions of neurotoxicology in China. Environ Health Perspect 124:722-732; http://dx.doi.org/10.1289/ehp.1409566.

Statin Use and the Risk of Parkinson's Disease: An Updated Meta-Analysis

INTRODUCTION

In response to the ongoing debate over the relationship between the use of statins and the risk of Parkinson's disease (PD), we performed a systematic review and meta-analysis of observational studies to examine their association.

METHODS

We conducted a review of the literature using electronic databases supplemented by a manual search to identify potentially relevant case-control or cohort studies. Summary relative risk (RRs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Sensitivity and subgroup analyses were also conducted.

RESULTS

Eleven studies (five case-control and six cohort) with a total of 3,513,209 participants and 21,011 PD cases were included. Statin use was associated with a lower risk of PD, with a summary RR of 0.81 (95% CI 0.71-0.92). Sensitivity analysis demonstrated the robustness of results. Subgroup analyses showed that neither study design nor study region significantly influenced the effect estimates. However, subgroup studies adjusted for age or sex had a greater inverse association than did unadjusted analyses (age-adjusted RR 0.75, 95% CI 0.60-0.95; age-unadjusted RR 0.86, 95% CI 0.75-0.99 and sex-adjusted RR 0.76, 95% CI 0.59-0.98; sex-unadjusted RR 0.85, 95% CI 0.79-0.92).

CONCLUSIONS

Results of this systematic review suggest that statin use is associated with a reduced PD risk. However, randomized controlled trials and more observational studies should be performed before strong conclusions are drawn.

The neuroprotective effect of lovastatin on MPP(+)-induced neurotoxicity is not mediated by PON2

Parkinson's disease (PD) is a neurodegenerative disorder characterized by loss of the pigmented dopaminergic neurons in the substantia nigra pars compacta with subsequent striatal dopamine (DA) deficiency and increased lipid peroxidation. The etiology of the disease is still unclear and it is thought that PD may be caused by a combination of genetic and environmental factors. In the search of new pharmacological options, statins have been recognized for their potential application to treat PD, due to their antioxidant effect. The aim of this work is to contribute in the characterization of the neuroprotective effect of lovastatin in a model of PD induced by 1-methyl-4-phenylpyridinium (MPP(+)). Male Wistar rats (200-250 g) were randomly allocated into 4 groups and administered for 7 days with different pharmacological treatments. Lovastatin administration (5 mg/kg) diminished 40% of the apomorphine-induced circling behavior, prevented the striatal DA depletion and lipid peroxides formation by MPP(+) intrastriatal injection, as compared to the group of animals treated only with MPP(+). Lovastatin produced no change in paraoxonase-2 (PON2) activity. It is evident that lovastatin conferred neuroprotection against MPP(+)-induced protection but this effect was not associated with the induction of PON2 in the rat striatum.

Neurotoxin mechanisms and processes relevant to Parkinson's disease: an update

The molecular mechanism responsible for degenerative process in the nigrostriatal dopaminergic system in Parkinson's disease (PD) remains unknown. One major advance in this field has been the discovery of several genes associated to familial PD, including alpha synuclein, parkin, LRRK2, etc., thereby providing important insight toward basic research approaches. There is an consensus in neurodegenerative research that mitochon dria dysfunction, protein degradation dysfunction, aggregation of alpha synuclein to neurotoxic oligomers, oxidative and endoplasmic reticulum stress, and neuroinflammation are involved in degeneration of the neuromelanin-containing dopaminergic neurons that are lost in the disease. An update of the mechanisms relating to neurotoxins that are used to produce preclinical models of Parkinson´s disease is presented. 6-Hydroxydopamine, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and rotenone have been the most wisely used neurotoxins to delve into mechanisms involved in the loss of dopaminergic neurons containing neuromelanin. Neurotoxins generated from dopamine oxidation during neuromelanin formation are likewise reviewed, as this pathway replicates neurotoxin-induced cellular oxidative stress, inactivation of key proteins related to mitochondria and protein degradation dysfunction, and formation of neurotoxic aggregates of alpha synuclein. This survey of neurotoxin modeling-highlighting newer technologies and implicating a variety of processes and pathways related to mechanisms attending PD-is focused on research studies from 2012 to 2014.