Estimates of Intracellular Dopamine in Parkinson’s Disease: A Systematic Review and Meta-Analysis

Journal of Parkinson s Disease ◽

10.3233/jpd-212715 ◽

2021 ◽

pp. 1-8

Author(s):

Jonathan Sackner-Bernstein

Keyword(s):

Systematic Review ◽

Parkinson’S Disease ◽

Parkinson's Disease ◽

Meta Analysis ◽

Dopamine Synthesis ◽

Similar Degree ◽

Normal Brain ◽

Protein Levels ◽

Neuroprotective Strategies ◽

Meta Analyses

Background: The hallmark of Parkinson’s disease is depletion of dopamine in the basal ganglia. Models of Parkinson’s disease include dopamine as a contributor to disease progression. However, intraneuronal levels of dopamine have not been reported. Objective: Meta-analytic methods were utilized to determine intracellular dopamine levels in Parkinson’s disease. Methods: A systematic review of the literature and frequentist meta-analyses were performed. Dopamine levels were scaled for cell and axon numbers as well as VMAT2 protein levels. Results: Reduced tissue dopamine, dopaminergic cell bodies and VMAT2 protein were confirmed. The ratio of Parkinson’s to normal brain intracellular dopamine scaled for either cell or axon number, each with VMAT2 level in the caudate ranged from 1.49 to 1.87 (p = 0.51 and p = 0.12, respectively) and in the putamen from 0.75 to 4.61 (p = 0.40 and 0.001, respectively). Conclusion: Free, intracellular dopamine levels are not reduced in Parkinson’s disease compared to normals to a similar degree as are total tissue concentrations, supporting the relevance of modulating VMAT2, neuromelanin and/or dopamine synthesis as rational neuroprotective strategies.

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Auditory and visual hallucination prevalence in Parkinson's disease and dementia with Lewy bodies: a systematic review and meta-analysis

Psychological Medicine ◽

10.1017/s0033291718003161 ◽

2018 ◽

Vol 49 (14) ◽

pp. 2342-2353 ◽

Cited By ~ 4

Author(s):

Charlotte Louise Eversfield ◽

Llwyd David Orton

Keyword(s):

Systematic Review ◽

Parkinson’S Disease ◽

Parkinson's Disease ◽

Dementia With Lewy Bodies ◽

Meta Analysis ◽

Lewy Bodies ◽

Eligibility Criteria ◽

Pooled Prevalence ◽

Prevalence Estimates ◽

Meta Analyses

AbstractBackgroundNon-motor features of Parkinson's disease (PD) and dementia with Lewy bodies (DLB), such as auditory hallucinations (AH), contribute to disease burden but are not well understood.MethodsSystematic review and random-effects meta-analyses of studies reporting AH associated with PD or DLB. Prevalence of visual hallucinations (VH) in identified studies meeting eligibility criteria were included in meta-analyses, facilitating comparison with AH. Synthesis of qualitative descriptions of AH was performed. PubMed, Web of Science and Scopus databases were searched for primary journal articles, written in English, published from 1970 to 2017. Studies reporting AH prevalence in PD or DLB were screened using PRISMA methods.ResultsSearches identified 4542 unique studies for consideration, of which, 26 met inclusion criteria. AH pooled prevalence in PD was estimated to be 8.9% [95% confidence interval (CI) 5.3–14.5], while in DLB was estimated to be 30.8% (±23.4 to 39.3). Verbal hallucinations, perceived as originating outside the head, were the most common form of AH. Non-verbal AH were also common while musical AH were rare. VH were more prevalent, with an estimated pooled prevalence in PD of 28.2% (±19.1 to 39.5), while in DLB they were estimated to be 61.8% (±49.1 to 73.0). Meta-regression determined that the use of validated methodologies to identify hallucinations produced higher prevalence estimates.ConclusionsAH and VH present in a substantial proportion of PD and DLB cases, with VH reported more frequently in both conditions. Both AH and VH are more prevalent in DLB than PD. There is a need for standardised use of validated methods to detect and monitor hallucinations.

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Auditory and visual hallucination prevalence in Parkinson’s disease and dementia with Lewy bodies: a systematic review and meta-analysis

10.31219/osf.io/spjd7 ◽

2018 ◽

Author(s):

Charlotte Louise Eversfield ◽

Llwyd David Orton

Keyword(s):

Systematic Review ◽

Parkinson’S Disease ◽

Parkinson's Disease ◽

Dementia With Lewy Bodies ◽

Psychotic Disorders ◽

Meta Analysis ◽

Lewy Bodies ◽

Eligibility Criteria ◽

Pooled Prevalence ◽

Meta Analyses

Background: Non-motor features of Parkinson’s disease (PD) and dementia with Lewy bodies (DLB) contribute significantly to disease burden yet are less well understood than motor features. Auditory hallucinations (AH) are commonly associated with psychotic disorders, yet their contribution to PD and DLB is not well understood.Methods: We conducted a systematic review and random-effects model meta-analyses of studies reporting AH associated with PD or DLB. Prevalence of visual hallucinations (VH) in identified studies meeting eligibility criteria were included in meta-analyses, facilitating comparison with AH. Synthesis of qualitative descriptions of AH was performed. PubMed, Web of Science and Scopus databases were searched for primary journal articles, written in English, published from 1970 to 2017. Studies reporting AH prevalence in PD or DLB were screened using PRISMA methods. Results: Searches identified 4,542 unique studies for consideration, of which, 26 met inclusion criteria. AH pooled prevalence in PD was estimated to be 8.9% (95% CI=5.3-14.5), while in DLB was estimated to be 30.8% (±23.4-39.3). VH were more common, with an estimated pooled prevalence in PD of 28.2% (±19.1-39.5), while in DLB they were estimated to be 61.8% (±49.1-73.0). Meta-regression determined that the use of validated methodologies to identify hallucinations produced higher prevalence estimates.Conclusions: AH and VH present in a substantial proportion of PD and DLB cases, with VH reported more frequently in both conditions. Both AH and VH are more prevalent in DLB than PD. There is a need for standardised use of validated methods to detect and monitor hallucinations.

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A systematic review of nutritional risk factors of Parkinson's disease

Nutrition Research Reviews ◽

10.1079/nrr2005108 ◽

2005 ◽

Vol 18 (2) ◽

pp. 259-282 ◽

Cited By ~ 28

Author(s):

Lianna Ishihara ◽

Carol Brayne

Keyword(s):

Risk Factors ◽

Systematic Review ◽

Parkinson’S Disease ◽

Parkinson's Disease ◽

Cohort Studies ◽

Meta Analysis ◽

Caffeine Intake ◽

Inverse Association ◽

Coffee Drinking ◽

Meta Analyses

A wide variety of nutritional exposures have been proposed as possible risk factors for Parkinson's disease (PD) with plausible biological hypotheses. Many studies have explored these hypotheses, but as yet no comprehensive systematic review of the literature has been available. MEDLINE, EMBASE, and WEB OF SCIENCE databases were searched for existing systematic reviews or meta-analyses of nutrition and PD, and one meta-analysis of coffee drinking and one meta-analysis of antioxidants were identified. The databases were searched for primary research articles, and articles without robust methodology were excluded by specified criteria. Seven cohort studies and thirty-three case–control (CC) studies are included in the present systematic review. The majority of studies did not find significant associations between nutritional factors and PD. Coffee drinking and alcohol intake were the only exposures with a relatively large number of studies, and meta-analyses of each supported inverse associations with PD. Factors that were reported by at least one CC study to have significantly increased consumption among cases compared with controls were: vegetables, lutein, xanthophylls, xanthins, carbohydrates, monosaccharides, junk food, refined sugar, lactose, animal fat, total fat, nuts and seeds, tea, Fe, and total energy. Factors consumed significantly less often among cases were: fish, egg, potatoes, bread, alcohol, coffee, tea, niacin, pantothenic acid, folate and pyridoxine. In three cohort studies, two reported borderline decreased relative risks and one a significant increased risk with vitamin C intake. One cohort reported an inverse association between caffeine intake and PD. Three cohorts reported significant positive association in men between dairy products and PD.

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