Parkinson's Disease in Women and Men: What's the Difference?

Incidence of Parkinson disease in North America

Parkinson disease (PD) is the second most common age-related neurodegenerative condition diagnosed in North America. We recently demonstrated, using multiple epidemiological data sources, that the prevalence of PD diagnoses was greater than previously reported and currently used for clinical, research, and policy decision-making. Prior PD incidence estimates have varied, for unclear reasons. There is a need for improved estimates of PD incidence, not only for care delivery planning and future policy but also for increasing our understanding of disease risk. The objective of this study was thus to investigate the incidence of Parkinson disease across five epidemiological cohorts in North America in a common year, 2012. The cohorts contained data on 6.7 million person-years of adults ages 45 and older, and 9.3 million person-years of adults ages 65 and older. Our estimates of age-sex-adjusted incidence of PD ranged from 108 to 212 per 100,000 among persons ages 65 and older, and from 47 to 77 per 100,00 among persons ages 45 and older. PD incidence increased with age and was higher among males. We also found persistent spatial clustering of incident PD diagnoses in the U.S. PD incidence estimates varied across our data sources, in part due to case ascertainment and diagnosis methods, but also possibly due to the influence of population factors (prevalence of genetic risk factors or protective markers) and geographic location (exposure to environmental toxins). Understanding the source of these variations will be important for health care policy, research, and care planning.

Prevalence of Malnutrition in Patients with Parkinson's Disease: A Systematic Review

OBJECTIVES

This systematic review analyzed the prevalence of malnutrition in patients with Parkinson's Disease.

STUDY DESIGN

a systematic review.

METHOD

Four databases-Cochrane, PubMed, Embase and Web of Science-were searched from October 2021 to June 2022 by two independent researchers. The inclusion criteria were as follows: patients above 18 years old with confirmed Parkinson's Disease, performed screening nutritional assessment, cohort studies, case-control studies, and cross-sectional studies. Patients without Parkinson's Disease and with other parkinsonian syndromes were excluded.

RESULTS

49 studies were included in this systematic review. Patients ranged in age from 20 to 96 years. There were 5613 subjects included. According to Mini Nutritional Assessment, 23.9% (n = 634) participants were at risk of malnutrition and 11.1% (n = 294) were malnourished. According to BMI score, most patients were either obese or overweight.

CONCLUSIONS

the prevalence of malnutrition or risk of malnutrition in the study group was significant. Therefore, more specific and detailed studies on the prevalence of malnutrition in patients with Parkinson's Disease are needed.

PGCLCs of human 45,XO reveal pathogenetic pathways of neurocognitive and psychosocial disorders

Background

Neurocognitive disorders and psychosocial difficulties are common in patients with Turner syndrome and multiple neurodegenerative diseases, yet there is no effective cure. Human primordial germ cells (hPGCs) are pluripotent germline stem cells in early embryo, which pass genetic information from one generation to the next, whereas all somatic cells will die along with the end of life. However, it is not known whether patient hPGCs with Turner syndrome contain information of neurocognitive and psychosocial illness.

Results

In this report, we used a high-density of culture system of embryoids derived from iPSCs of a patient with Turner syndrome to ask how pathogenetic pathways are associated with onset of neurocognitive and psychosocial disorders. The hPGC-Like Cells (hPGCLCs) were in vitro specified from iPSCs of 45,XO, 46,XX and 46,XY by the high-density induction of embryoids. Amazingly, we found that the specification process of the hPGCLCs in 45,XO, compared to those in 46,XX and 46,XY, enriched several common pathogenetic pathways regulating neurocognitive and psychosocial disorders, that shared among multiple neurodegenerative diseases and Turner syndrome. The downregulated chemical synaptic transmission pathways, including glutamatergic, GABAergic, and nicotine cholinergic synapses, indicated synaptic dysfunctions, while upregulated pathways that were associated with imbalance of mitochondrial respiratory chain complexes and apoptosis, may contribute to neuronal dysfunctions. Notably, downregulation of three types of ubiquitin ligases E1-E2-E3 and lysosome-associated sulfatases and RAB9A, owing to haploinsufficiency and parental preference of the X chromosome expression, indicated that two pathways of cellular degradation, lysosome and ubiquitin–proteasome, were impaired in the specification process of 45,XO hPGCLCs. This would lead to accumulation of undesired proteins and aggregates, which is a typically pathological hallmark in neurodegenerative diseases.

Conclusions

Our data suggest that the specification process of the hPGCLCs in 45,XO, compared to those in 46,XX and 46,XY, enriched pathogenetic pathways that are associated with the onset of neurocognitive and psychosocial disorders.

Repetitive mild TBI causes pTau aggregation in nigra without altering preexisting fibril induced Parkinson's-like pathology burden

Population studies have shown that traumatic brain injury (TBI) is associated with an increased risk for Parkinson's disease (PD) and among U.S. Veterans with a history of TBI this risk is 56% higher. The most common type of TBI is mild (mTBI) and often occurs repeatedly among athletes, military personnel, and victims of domestic violence. PD is classically characterized by deficits in fine motor movement control resulting from progressive neurodegeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) midbrain region. This neurodegeneration is preceded by the predictable spread of characteristic alpha synuclein (αSyn) protein inclusions. Whether repetitive mTBI (r-mTBI) can nucleate PD pathology or accelerate prodromal PD pathology remains unknown. To answer this question, an injury device was constructed to deliver a surgery-free r-mTBI to rats and human-like PD pathology was induced by intracranial injection of recombinant αSyn preformed fibrils. At the 3-month endpoint, the r-mTBI caused encephalomalacia throughout the brain reminiscent of neuroimaging findings in patients with a history of mTBI, accompanied by astrocyte expansion and microglial activation. The pathology associated most closely with PD, which includes dopaminergic neurodegeneration in the SNpc and Lewy body-like αSyn inclusion burden in the surviving neurons, was not produced de novo by r-mTBI nor was the fibril induced preexisting pathology accelerated. r-mTBI did however cause aggregation of phosphorylated Tau (pTau) protein in nigra of rats with and without preexisting PD-like pathology. pTau aggregation was also found to colocalize with PFF induced αSyn pathology without r-mTBI. These findings suggest that r-mTBI induced pTau aggregate deposition in dopaminergic neurons may create an environment conducive to αSyn pathology nucleation and may add to preexisting proteinaceous aggregate burden.

Doxycycline attenuates l-DOPA-induced dyskinesia through an anti-inflammatory effect in a hemiparkinsonian mouse model

The pharmacological manipulation of neuroinflammation appears to be a promising strategy to alleviate l-DOPA-induced dyskinesia (LID) in Parkinson's disease (PD). Doxycycline (Doxy), a semisynthetic brain-penetrant tetracycline antibiotic having interesting anti-inflammatory properties, we addressed the possibility that this compound could resolve LID in l-DOPA-treated C57BL/6 mice presenting either moderate or intermediate lesions of the mesostriatal dopaminergic pathway generated by intrastriatal injections of 6-OHDA. Doxy, when given subcutaneously before l-DOPA at doses of 20 mg kg^-1 and 40 mg kg^-1, led to significant LID reduction in mice with moderate and intermediate dopaminergic lesions, respectively. Importantly, Doxy did not reduce locomotor activity improved by l-DOPA. To address the molecular mechanism of Doxy, we sacrificed mice with mild lesions 1) to perform the immunodetection of tyrosine hydroxylase (TH) and Fos-B and 2) to evaluate a panel of inflammation markers in the striatum, such as cyclooxygenase-2 and its downstream product Prostaglandin E2 along with the cytokines TNF-α, IL-1β and IL-6. TH-immunodetection revealed that vehicle and Doxy-treated mice had similar striatal lesions, excluding that LID improvement by Doxy could result from neurorestorative effects. Importantly, LID inhibition by Doxy was associated with decreased Fos-B and COX-2 expression and reduced levels of PGE₂, TNF-α, and IL-1β in the dorsolateral striatum of dyskinetic mice. We conclude 1) that Doxy has the potential to prevent LID regardless of the intensity of dopaminergic lesioning and 2) that the anti-inflammatory effects of Doxy probably account for LID attenuation. Overall, the present results further indicate that Doxy might represent an attractive and alternative treatment for LID in PD.

Machine learning based risk prediction for Parkinson's disease with nationwide health screening data

Although many studies have been conducted on machine learning (ML) models for Parkinson's disease (PD) prediction using neuroimaging and movement analyses, studies with large population-based datasets are limited. We aimed to propose PD prediction models using ML algorithms based on the National Health Insurance Service-Health Screening datasets. We selected individuals who participated in national health-screening programs > 5 times between 2002 and 2015. PD was defined based on the ICD-code (G20), and a matched cohort of individuals without PD was selected using a 1:1 random sampling method. Various ML algorithms were applied for PD prediction, and the performance of the prediction models was compared. Neural networks, gradient boosting machines, and random forest algorithms exhibited the best average prediction accuracy (average area under the receiver operating characteristic curve (AUC): 0.779, 0.766, and 0.731, respectively) among the algorithms validated in this study. The overall model performance metrics were higher in men than in women (AUC: 0.742 and 0.729, respectively). The most important factor for predicting PD occurrence was body mass index, followed by total cholesterol, glucose, hemoglobin, and blood pressure levels. Smoking and alcohol consumption (in men) and socioeconomic status, physical activity, and diabetes mellitus (in women) were highly correlated with the occurrence of PD. The proposed health-screening dataset-based PD prediction model using ML algorithms is readily applicable, produces validated results, and could be a useful option for PD prediction models.

Identification of hub genes of Parkinson's disease through bioinformatics analysis

Parkinson's disease (PD) is a common neurodegenerative disease, and there is still a lack of effective diagnostic and treatment methods. This study aimed to search for hub genes that might serve as diagnostic or therapeutic targets for PD. All the analysis was performed in R software. The expression profile data of PD (number: GSE7621) was acquired from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) associated with PD were screened by the “Limma” package of the R software. Key genes associated with PD were screened by the “WGCNA” package of the R software. Target genes were screened by merging the results of “Limma” and “WGCNA.” Enrichment analysis of target genes was performed by Gene Ontology (GO), Disease Ontology (DO), and Kyoto Enrichment of Genes and Genomes (KEGG). Machine learning algorithms were employed to screen for hub genes. Nomogram was constructed using the “rms” package. And the receiver operating characteristic curve (ROC) was plotted to detect and validate our prediction model sensitivity and specificity. Additional expression profile data of PD (number: GSE20141) was acquired from the GEO database to validate the nomogram. GSEA was used to determine the biological functions of the hub genes. Finally, RPL3L, PLEK2, PYCRL, CD99P1, LOC100133130, MELK, LINC01101, and DLG3-AS1 were identified as hub genes of PD. These findings can provide a new direction for the diagnosis and treatment of PD.

Differences in Sex-Specific Frequency of Glucocerebrosidase Variant Carriers and Familial Parkinsonism

BACKGROUND

Although men and women with the LRRK2 G2019S variant appear to be equally likely to have Parkinson's disease (PD), the sex-distribution among glucocerebrosidase (GBA) variant carriers with PD, including limited to specific variant severities of GBA, is not well understood. Further, the sex-specific genetic contribution to PD without a known genetic variant is controversial.

OBJECTIVES

To better understand sex differences in genetic contribution to PD, especially sex-specific frequencies among GBA variant carriers with PD (GBA PD) and LRRK2-G2019S variant carriers with PD (LRRK2 PD).

METHODS

We assess differences in the sex-specific frequency in GBA PD, including in subsets of GBA variant severity, LRRK2 PD, and idiopathic PD in an Ashkenazi Jewish cohort with PD. Further, we expand prior work evaluating differences in family history of parkinsonism.

RESULTS

Both idiopathic PD (267/420 men, 63.6%) (P < 0.001) and GBA PD overall (64/107, 59.8%) (P = 0.042) were more likely to be men, whereas no difference was seen in LRRK2 PD (50/99, 50.5%) and LRRK2/GBA PD (5/10, 50%). However, among GBA PD probands, severe variant carriers were more likely to be women (15/19 women, 79.0%) (P = 0.005), whereas mild variant carriers (44/70 men, 62.9%) (P = 0.039) and risk-variant carriers (15/17 men, 88.2%) (P = 0.001) were more likely to be men.

CONCLUSIONS

Our study demonstrates that the male-sex predominance present in GBA PD overall was not consistent across GBA variant severities, and a female-sex predominance was present among severe GBA variant carriers. Therefore, research and trial designs for PD should consider sex-specific differences, including across GBA variant severities. © 2022 International Parkinson and Movement Disorder Society.

Effect Modification between Genes and Environment and Parkinson's Disease Risk

Parkinson's disease (PD) is a complex neurodegenerative condition in which genetic and environmental factors interact to contribute to its etiology. Remarkable progress has been made in deciphering disease etiology through genetic approaches, but there is limited data about how environmental and genetic factors interact to modify penetrance, risk, and disease severity. Here, we provide insights into environmental modifiers of PD, discussing precedents from other neurological and non-neurological conditions. Based on these examples, we outline genetic and environmental factors contributing to PD and review potential environmental modifiers of penetrance and clinical variability in monogenic and idiopathic PD. We also highlight the potential challenges and propose how future studies might tackle these important questions. ANN NEUROL 2022;92:715-724.

Role of SUMOylation in Neurodegenerative Diseases

Neurodegenerative diseases (NDDs) are irreversible, progressive diseases with no effective treatment. The hallmark of NDDs is the aggregation of misfolded, modified proteins, which impair neuronal vulnerability and cause brain damage. The loss of synaptic connection and the progressive loss of neurons result in cognitive defects. Several dysregulated proteins and overlapping molecular mechanisms contribute to the pathophysiology of NDDs. Post-translational modifications (PTMs) are essential regulators of protein function, trafficking, and maintaining neuronal hemostasis. The conjugation of a small ubiquitin-like modifier (SUMO) is a reversible, dynamic PTM required for synaptic and cognitive function. The onset and progression of neurodegenerative diseases are associated with aberrant SUMOylation. In this review, we have summarized the role of SUMOylation in regulating critical proteins involved in the onset and progression of several NDDs.

The Role of Diet and Dietary Patterns in Parkinson's Disease

Parkinson's Disease (PD) is a neurodegenerative disorder associated with diminished nutrition status and decreased quality of life. While the prevalence of PD is expected to increase, no preventative or curative therapy for PD exists at this time. Although nutrition and diet represent modifiable risk factors for reducing chronic disease risk, research on the impact of single nutrients on PD has yielded mixed results. As a result, this single-nutrient approach may be the driving force behind the inconsistency, and a holistic dietary approach may overcome this inconsistency by accounting for the interactions between nutrients. The following review aims to examine the impact of a generally healthy dietary pattern, the protein-restricted diet (PRD), the ketogenic diet (KD), the Mediterranean diet (MD), and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet on PD risk, progression, and severity. While most of the included studies support the role of diet and dietary patterns in reducing the risk of PD or alleviating PD severity, the inconsistent results and need for further evidence necessitate more research being conducted before making dietary recommendations. Research on the potential beneficial effects of dietary patterns on PD should also investigate potential risks.

State-of-the-art review of the clinical research on menopause and hormone replacement therapy association with Parkinson's disease: What meta-analysis studies cannot tell us

The menopause is a midlife endocrinological process that greatly affects women's central nervous system functions. Over the last 2 decades numerous clinical studies have addressed the influence of ovarian hormone decline on neurological disorders like Parkinson's disease and Alzheimer's disease. However, the findings in support of a role for age at menopause, type of menopause and hormone replacement therapy on Parkinson's disease onset and its core features show inconsistencies due to the heterogeneity in the study design. Here, we provide a unified overview of the clinical literature on the influence of menopause and ovarian hormones on Parkinson's disease. We highlight the possible sources of conflicting evidence and gather considerations for future observational clinical studies that aim to explore the neurological impact of menopause-related features in Parkinson's disease.

Association of Premenopausal Bilateral Oophorectomy With Parkinsonism and Parkinson Disease

IMPORTANCE

The association of premenopausal bilateral oophorectomy with parkinsonism and Parkinson disease (PD) remains controversial.

OBJECTIVE

To assess whether women who underwent premenopausal bilateral oophorectomy were at increased risk of parkinsonism and PD and whether the associations varied by age at oophorectomy and by receipt of estrogen replacement therapy.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from a combination of 2 independent cohort studies, the Mayo Clinic Cohort Study of Oophorectomy and Aging 1 and 2, which were based on the Rochester Epidemiology Project medical records-linkage system. A population-based sample of 5499 women from Olmsted County, Minnesota, were included; of those, 2750 women underwent bilateral oophorectomy for a benign indication before spontaneous menopause between January 1, 1950, and December 31, 2007 (oophorectomy cohort), and 2749 age-matched women who did not undergo bilateral oophorectomy were randomly sampled from the general population (reference cohort). Data were analyzed from March 1 to April 30, 2022. The date of oophorectomy was considered the index date for both groups.

EXPOSURES

Medical record documentation of bilateral oophorectomy abstracted from a medical records-linkage system (Rochester Epidemiology Project).

MAIN OUTCOMES AND MEASURES

Incidence and risk of parkinsonism or PD, with diagnoses confirmed by in-person examination or medical record review.

RESULTS

Among 5499 participants (median [IQR] age, 45.0 [40.0-48.0] years; 5312 [96.6%] White), 2750 women (2679 White [97.4%]) underwent bilateral oophorectomy at a median age of 45.0 years (IQR, 40.0-48.0 years), and 2749 women (2633 White [95.8%]) with a median age of 45.0 years (IQR, 40.0-48.0 years) at the index date were included in the reference cohort. Bilateral oophorectomy was associated with an increased risk of parkinsonism overall (hazard ratio [HR], 1.59; 95% CI, 1.02-2.46) and in women younger than 43 years at oophorectomy (HR, 7.67; 95% CI, 1.77-33.27). There was a pattern of increasing risk with younger age at the time of oophorectomy using 4 age strata (≥50 years: HR, 1.43 [95% CI, 0.50-4.15]; 46-49 years: HR, 1.55 [95% CI, 0.79-3.07]; 40-45 years: HR, 1.36 [95% CI, 0.64-2.89]; <40 years: HR, 8.82 [95% CI, 1.08-72.00]; P = .02 for trend). The number needed to harm was 53 women overall and 27 women younger than 43 years at the time of oophorectomy. Bilateral oophorectomy was also associated with an increased risk of PD in women younger than 43 years at oophorectomy (HR, 5.00; 95% CI, 1.10-22.70), with a number needed to harm of 48 women. Among women who underwent oophorectomy at 45 years and younger, the risk was lower in women who received estrogen after the procedure and through age 50 years compared with women who did not. For parkinsonism, the HRs were 1.72 (95% CI, 0.54-5.53) vs 2.05 (95% CI, 0.80-5.23); for PD, the HRs were 1.53 (95% CI, 0.29-8.23) vs 2.75 (95% CI, 0.84-9.04). However, the differences were not significant.

CONCLUSIONS AND RELEVANCE

In this study, premenopausal women who underwent bilateral oophorectomy before age 43 years had an increased risk of parkinsonism and PD compared with women who did not undergo bilateral oophorectomy. These findings suggest that a reduction in the practice of prophylactic bilateral oophorectomy in premenopausal women at average risk of ovarian cancer may have substantial benefit for reducing the risk of parkinsonism and PD.

Dyskinesia and Parkinson's disease: animal model, drug targets, and agents in preclinical testing

INTRODUCTION

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease. PD patients exhibit a classic spectrum of motor symptoms, arising when dopamine neurons in the substantia nigra pars compacta are reduced by 60%. The dopamine precursor L-DOPA represents the most effective therapy for improving PD motor dysfunctions, thus far available. Unfortunately, long-term treatment with L-DOPA is associated with the development of severe side effects, resulting in abnormal involuntary movements termed levodopa-induced dyskinesia (LID). Amantadine is the only drug currently approved for the treatment of LID indicating that LID management is still an unmet need in PD and encouraging the search for novel anti-dyskinetic drugs or the assessment of combined therapies with different molecular targets.

AREAS COVERED

This review provides an overview of the main preclinical models used to study LID and of the latest preclinical evidence on experimental and clinically available pharmacological approaches targeting non-dopaminergic systems.

EXPERT OPINION

LIDs are supported by complex molecular and neurobiological mechanisms that are still being studied today. This complexity suggests the need of developing personalized pharmacological approach to obtain an effective amelioration of LID condition and improve the quality of life of PD patients.

Parkinsonism-Hyperpyrexia Syndrome: A Case Series and Literature Review

Parkinsonism-hyperpyrexia syndrome (PHS) is a rare, potentially fatal neurological emergency, that is seen in Parkinson’s Disease (PD) patients and mimics neuroleptic malignant syndrome. The most common trigger for PHS is sudden withdrawal of anti-parkinsonian medications, specifically levodopa. However, it can also be due to Deep Brain Stimulation (DBS) device malfunction. In this work, we describe three cases of PHS; the first of which is related to DBS battery depletion, and the remaining two to dopaminergic withdrawal. Additionally, we will include the results of a literature review on PHS, its etiologies, presentation, and management.

Network Pharmacology and Molecular Docking Analyses Unveil the Mechanisms of Yiguanjian Decoction against Parkinson’s Disease from Inner/Outer Brain Perspective

Objective

This study aims to explore the pharmacodynamic mechanism of Yiguanjian (YGJ) decoction against Parkinson's disease (PD) through integrating the central nervous (inner brain) and peripheral system (outer brain) relationship spectrum.

Methods

The active components of YGJ were achieved from the TCMSP, TCMID, and TCM@Taiwan databases. The blood-brain barrier (BBB) permeability of the active components along with their corresponding targets was evaluated utilizing the existing website, namely, SwissADME and SwissTargetPrediction. The targets of PD were determined through database retrieval. The interaction network was constructed upon the STRING database, followed by the visualization using Cytoscape software. Then, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses on potential targets. Finally, the molecular docking approach was employed to assess the binding affinity between key components and key targets.

Results

Overall, we identified 79 active components, 128 potential targets of YGJ, and 97 potential targets of YGJ-BBB potentially suitable for the treatment of PD. GO and KEGG analyses showed that the YGJ treatment of PD mainly relied on PI3K-Akt pathway while the YGJ-BBB was mostly involved in endocrine resistance. The molecular docking results displayed high affinity between multiple compounds and targets in accordance with previous observations.

Conclusions

Our study unveiled the potential mechanisms of YGJ against PD from a systemic perspective: (1) for the YGJ, they have potential exerting effects on the peripheral system and inhibiting neuronal apoptosis through regulating the PI3K-Akt pathway; (2) for the YGJ-BBB, they can directly modulate endocrine resistance of the central nervous and holistically enhance body resistance to PD along with YGJ on PI3K-Akt pathway.

Parkinson's disease-associated, sex-specific changes in DNA methylation at PARK7 (DJ-1), SLC17A6 (VGLUT2), PTPRN2 (IA-2β), and NR4A2 (NURR1) in cortical neurons

Evidence for epigenetic regulation playing a role in Parkinson's disease (PD) is growing, particularly for DNA methylation. Approximately 90% of PD cases are due to a complex interaction between age, genes, and environmental factors, and epigenetic marks are thought to mediate the relationship between aging, genetics, the environment, and disease risk. To date, there are a small number of published genome-wide studies of DNA methylation in PD, but none accounted for cell type or sex in their analyses. Given the heterogeneity of bulk brain tissue samples and known sex differences in PD risk, progression, and severity, these are critical variables to account for. In this genome-wide analysis of DNA methylation in an enriched neuronal population from PD postmortem parietal cortex, we report sex-specific PD-associated methylation changes in PARK7 (DJ-1), SLC17A6 (VGLUT2), PTPRN2 (IA-2β), NR4A2 (NURR1), and other genes involved in developmental pathways, neurotransmitter packaging and release, and axon and neuron projection guidance.

Small soluble α-synuclein aggregates are the toxic species in Parkinson's disease

Soluble α-synuclein aggregates varying in size, structure, and morphology have been closely linked to neuronal death in Parkinson's disease. However, the heterogeneity of different co-existing aggregate species makes it hard to isolate and study their individual toxic properties. Here, we show a reliable non-perturbative method to separate a heterogeneous mixture of protein aggregates by size. We find that aggregates of wild-type α-synuclein smaller than 200 nm in length, formed during an in vitro aggregation reaction, cause inflammation and permeabilization of single-liposome membranes and that larger aggregates are less toxic. Studying soluble aggregates extracted from post-mortem human brains also reveals that these aggregates are similar in size and structure to the smaller aggregates formed in aggregation reactions in the test tube. Furthermore, we find that the soluble aggregates present in Parkinson's disease brains are smaller, largely less than 100 nm, and more inflammatory compared to the larger aggregates present in control brains. This study suggests that the small non-fibrillar α-synuclein aggregates are the critical species driving neuroinflammation and disease progression.

Inflammation in VTA Caused by HFD Induces Activation of Dopaminergic Neurons Accompanied by Binge-like Eating

Binge eating is a characteristic symptom observed in obese individuals that is related to dysfunction of dopaminergic neurons (DNs). Intermittent administration of a high-fat diet (HFD) is reported to induce binge-like eating, but the underlying mechanisms remain unclear. We generated dopaminergic neuron specific IKKβ deficient mice (KO) to examine the effects of inflammation in DNs on binge-like eating under inflammatory conditions associated with HFD. After administration of HFD for 4 weeks, mice were fasted for 24 h, and then the consumption of HFD was measured for 2 h. We also evaluated that the mRNA expressions of inflammatory cytokines, glial markers, and dopamine signaling-related genes in the ventral tegmental area (VTA) and striatum. Moreover, insulin was administered intraventricularly to assess downstream signaling. The consumption of HFD was significantly reduced, and the phosphorylation of AKT in the VTA was significantly increased in female KO compared to wild-type (WT) mice. Analyses of mRNA expressions revealed that DNs activity and inflammation in the VTA were significantly decreased in female KO mice. Thus, our data suggest that HFD-induced inflammation with glial cell activation in the VTA affects DNs function and causes abnormal eating behaviors accompanied by insulin resistance in the VTA of female mice.

The long-term trend of Parkinson’s disease incidence and mortality in China and a Bayesian projection from 2020 to 2030

Background: Parkinson’s disease is a disabling degenerative disease of the central nervous system that occurs mainly in elderly people. The changes in the incidence and mortality of Parkinson’s disease at the national level in China over the past three decades have not been fully explored.

Methods: Research data were obtained from the Global Burden of Disease 2019 study. The trends of crude and age-standardized incidence and mortality rates by gender of Parkinson’s disease in China were analyzed with the age-period-cohort model and the Joinpoint regression analysis. The effects of age, time period, and birth cohort on the incidence and mortality of Parkinson’s disease were estimated. The gender- and age-specific incidence and mortality rates of Parkinson’s disease from 2020 to 2030 were projected using the Bayesian age-period-cohort model with integrated nested Laplace approximations.

Results: From 1990 to 2019, the annual percentage change of the age-standardized incidence rate was 0.8% (95% CI: 0.7%–0.8%) for males and 0.2% (95% CI, 0.2–0.2%) for females. And the age-standardized mortality rate for males was 2.9% (95% CI: 2.6%–3.2%) and 1.8% (95% CI: 1.5%–2.1%) for females. The results of the age-period-cohort analysis suggested that the risk and burden of Parkinson’s disease continued to increase for the last several decades. Projection analysis suggested that the overall Parkinson’s disease incidence will continue to increase for the next decades. It was projected that China would have 4.787 million Parkinson’s patients by the year 2030, however, the mortality of Parkinson’s disease for both genders in China may keep decreasing.

Conclusion: Though the mortality risk may decrease, Parkinson’s disease continues to become more common for both genders in China, especially in the senior-aged population. The burden associated with Parkinson’s disease would continue to grow. Urgent interventions should be implemented to reduce the burden of Parkinson’s disease in China.

Correlation of biomarker cortisol with fatigue and quality of life among men and women with idiopathic Parkinson’s disease

Introduction and Aim: Fatigue is the prodromal symptom occurring as the earliest symptom even before motor symptoms. It has been unidentified, which also proves to be an untouched symptom for intervention. Little has been understood how men and women feel fatigued. The objective of this study is to find the correlation between fatigue and quality of life among men and women with idiopathic Parkinson’s disease (PD).  Materials and Methods: Recommended scale for fatigue as fatigue severity score and a biomarker salivary cortisol was correlated against the quality-of-life questionnaire as PDQ-39 among 25 PD male and female patients. Results: Females are found to show significantly higher values compared to males in PDQ and salivary cortisol. F values are significant for PDQ and salivary cortisol only (p < 0.01) when compared to the H/Y scale (‘r’ = 0.420). Conclusion: Females reported more fatigue and poor quality of life. Salivary cortisol can be a useful biomarker to measure and infer the level of fatigue which had been only feeling reported by the patients until now.

Aging, testosterone, and neuroplasticity: friend or foe?

Neuroplasticity or neural plasticity implicates the adaptive potential of the brain in response to extrinsic and intrinsic stimuli. The concept has been utilized in different contexts such as injury and neurological disease. Neuroplasticity mechanisms have been classified into neuroregenerative and function-restoring processes. In the context of injury, neuroplasticity has been defined in three post-injury epochs. Testosterone plays a key yet double-edged role in the regulation of several neuroplasticity alterations. Research has shown that testosterone levels are affected by numerous factors such as age, stress, surgical procedures on gonads, and pharmacological treatments. There is an ongoing debate for testosterone replacement therapy (TRT) in aging men; however, TRT is more useful in young individuals with testosterone deficit and more specific subgroups with cognitive dysfunction. Therefore, it is important to pay early attention to testosterone profile and precisely uncover its harms and benefits. In the present review, we discuss the influence of environmental factors, aging, and gender on testosterone-associated alterations in neuroplasticity, as well as the two-sided actions of testosterone in the nervous system. Finally, we provide practical insights for further study of pharmacological treatments for hormonal disorders focusing on restoring neuroplasticity.

Crosstalk between regulatory non-coding RNAs and oxidative stress in Parkinson’s disease

Parkinson’s disease is the second most common neurodegenerative disease after Alzheimer’s disease, which imposes an ever-increasing burden on society. Many studies have indicated that oxidative stress may play an important role in Parkinson’s disease through multiple processes related to dysfunction or loss of neurons. Besides, several subtypes of non-coding RNAs are found to be involved in this neurodegenerative disorder. However, the interplay between oxidative stress and regulatory non-coding RNAs in Parkinson’s disease remains to be clarified. In this article, we comprehensively survey and overview the role of regulatory ncRNAs in combination with oxidative stress in Parkinson’s disease. The interaction between them is also summarized. We aim to provide readers with a relatively novel insight into the pathogenesis of Parkinson’s disease, which would contribute to the development of pre-clinical diagnosis and treatment.

Task-specific effects of biological sex and sex hormones on object recognition memories in a 6-hydroxydopamine-lesion model of Parkinson's disease in adult male and female rats

Many patients with Parkinson's disease (PD) experience cognitive or memory impairments with few therapeutic options available to mitigate them. This has fueled interest in determining how factors including sex and sex hormones modulate higher order function in this disease. The objective of this study was to use the Novel Object Recognition (NOR) and Object-in-Place (OiP) paradigms to compare the effects of a bilateral neostriatal 6-hydroxydopamine (6-OHDA) lesion model of PD in gonadally intact male and female rats, in orchidectomized male rats and in orchidectomized males supplemented with 17β-estradiol or testosterone propionate on measures of recognition memory similar to those at risk in PD. These studies showed that 6-ODHA lesions impaired discrimination in both tasks in males but not females. Further, 6-OHDA lesions disrupted NOR performance similarly in all males regardless of whether they were gonadally intact, orchidectomized or hormone-supplemented. In contrast, OiP performance was disrupted in males that were orchidectomized or 6-OHDA-lesioned but was spared in orchidectomized and orchidectomized, 6-OHDA lesioned males supplemented with 17β-estradiol. The distinct effects that sex and/or sex hormones have on 6-OHDA lesion-induced NOR vs. OiP deficits identified here also differ from corresponding impacts recently described for 6-OHDA lesion-induced deficits in spatial working memory and episodic memory. Together, the collective data provide strong evidence for effects of sex and sex hormones on cognition and memory in PD as being behavioral task and behavioral domain specific. This specificity could explain why a cohesive clinical picture of endocrine impacts on higher order function in PD has remained elusive.

Artificial intelligence and machine-learning approaches in structure and ligand-based discovery of drugs affecting central nervous system

CNS disorders are indications with a very high unmet medical needs, relatively smaller number of available drugs, and a subpar satisfaction level among patients and caregiver. Discovery of CNS drugs is extremely expensive affair with its own unique challenges leading to extremely high attrition rates and low efficiency. With explosion of data in information age, there is hardly any aspect of life that has not been touched by data driven technologies such as artificial intelligence (AI) and machine learning (ML). Drug discovery is no exception, emergence of big data via genomic, proteomic, biological, and chemical technologies has driven pharmaceutical giants to collaborate with AI oriented companies to revolutionise drug discovery, with the goal of increasing the efficiency of the process. In recent years many examples of innovative applications of AI and ML techniques in CNS drug discovery has been reported. Research on therapeutics for diseases such as schizophrenia, Alzheimer's and Parkinsonism has been provided with a new direction and thrust from these developments. AI and ML has been applied to both ligand-based and structure-based drug discovery and design of CNS therapeutics. In this review, we have summarised the general aspects of AI and ML from the perspective of drug discovery followed by a comprehensive coverage of the recent developments in the applications of AI/ML techniques in CNS drug discovery.

Gender Differences in Personal and Situational Risk Factors for Traumatic Brain Injury Among Older Adults

OBJECTIVE

To investigate differences between older men and women in Taiwan in personal and situational risk factors for sustaining a traumatic brain injury (TBI) versus soft-tissue injury (STI) due to a fall.

DESIGN

Matched case-control study.

PARTICIPANTS AND SETTINGS

Cases were defined as patients with a primary diagnosis of TBI due to a fall and were identified from those 60 years or older who visited the emergency department (ED) of 3 university-affiliated hospitals in 2015. Matched by the same hospital ED, gender, and time of falling, 3 controls who had no TBI and who had sustained only soft-tissue injury (STI) due to falling were selected for comparison with each case. Personal factors and situational exposures were compared between the control and case groups. In total, 96 cases and 288 controls in men and 72 cases and 216 controls in women participated in this study.

MAIN MEASURES

Personal factors (sociodemographic and lifestyle factors, medical characteristics, and functional abilities) and situational exposures (location, activities before the fall, center-of-mass change, type of fall, falling direction, protective response, and impact during the fall).

RESULTS

In men, after adjusting for other variables, older age (odds ratio [OR] = 1.04), regular alcohol use (OR = 2.03), an indoor fall (OR = 1.92), activity of getting in/out of bed (OR = 2.56), a fall due to dizziness (OR = 4.09), and falling backward (OR = 2.95) were independently associated with a higher odds of TBI. In women, an older age (OR = 1.03), the presence of Parkinson disease (OR = 10.4), activities of toileting (OR = 2.50), getting in/out of bed (OR = 4.90), and negotiating stairs (OR = 7.13), a fall due to dizziness (OR = 5.05), and falling backward (OR = 2.61) were independently associated with a higher odds of TBI.

CONCLUSIONS

Our results demonstrated similarities and differences in personal and situational risk factors for fall-related TBIs versus STIs between older men and women, and gender differences should be considered when developing intervention strategies.

Nomogram for Predicting Depression Improvement after Deep Brain Stimulation for Parkinson’s Disease

Background: Parkinson’s disease is a common neurodegenerative disease, with depression being a common non-motor symptom. Bilateral subthalamic nucleus deep brain stimulation is an effective method for the treatment of Parkinson’s disease. Thus, this study aimed to establish a nomogram of the possibility of achieving a better depression improvement rate after subthalamic nucleus deep brain stimulation in patients with Parkinson’s disease. Methods: We retrospectively analyzed 103 patients with Parkinson’s disease who underwent subthalamic nucleus deep brain stimulation and were followed up for the improvement of their Hamilton Depression scale scores 1 year postoperatively. Univariate and multivariate logistic regression analyses were used to select factors affecting the improvement rate of depression. A nomogram was then developed to predict the possibility of achieving better depression improvement. Furthermore, the discrimination and fitting performance was evaluated using a calibration diagram, receiver operating characteristics, and decision curve analysis. Results: The mean and median improvement rates of Hamilton Depression scores were 13.1 and 33.3%, respectively. Among the 103 patients, 70.8% had an improved depression, 23.3% had a worsened depression, and 5.8% remained unchanged. Logistic multivariate regression analysis showed that age, preoperative Parkinson’s Disease Questionnaire, Hamilton Anxiety, and Hamilton Depression scores were independent factors for the possibility of achieving a better depression improvement rate. Based on these results, a nomogram model was developed. The nomogram had a C-index of 0.78 (95% confidence interval: 0.69–0.87) and an area under the receiver operating characteristics of 0.78 (95% confidence interval: 0.69–0.87). The calibration plot and decision curve analysis further demonstrated goodness-of-fit between the nomogram predictions and actual observations. Conclusion: We developed a nomogram to predict the possibility of achieving good depression improvement 1 year after subthalamic nucleus deep brain stimulation in patients with Parkinson’s disease, which showed a certain value in judging the expected depression improvement of these patients.

Nomogram to Predict Cognitive State Improvement after Deep Brain Stimulation for Parkinson's Disease

Purpose: Parkinson’s disease (PD) is a common neurodegenerative disease, for which cognitive impairment is a non-motor symptom (NMS). Bilateral subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment for PD. This study established a nomogram to predict cognitive improvement rate after STN-DBS in PD patients. Methods: We retrospectively analyzed 103 PD patients who underwent STN-DBS. Patients were followed up to measure improvement in MoCA scores one year after surgery. Univariate and multivariate logistic regression analyses were used to identify factors affecting improvement in cognitive status. A nomogram was developed to predict this factor. The discrimination and fitting performance were evaluated by receiver operating characteristics (ROC) analysis, calibration diagram, and decision curve analysis (DCA). Results: Among 103 patients, the mean improvement rate of the MoCA score was 37.3% and the median improvement rate was 27.3%, of which 64% improved cognition, 27% worsened cognition, and 8.7% remained unchanged. Logistic multivariate regression analysis showed that years of education, UPDRSIII drug use, MoCA Preop, and MMSE Preop scores were independent factors affecting the cognitive improvement rate. A nomogram model was subsequently developed. The C-index of the nomogram was 0.98 (95%CI, 0.97–1.00), and the area under the ROC was 0.98 (95%CI 0.97–1.00). The calibration plot and DCA demonstrated the goodness-of-fit between nomogram predictions and actual observations. Conclusion: Our nomogram could effectively predict the possibility of achieving good cognitive improvement one year after STN-DBS in patients with PD. This model has value in judging the expected cognitive improvement of patients with PD undergoing STN-DBS.

Voluntary Exercise Boosts Striatal Dopamine Release: Evidence for the Necessary and Sufficient Role of BDNF

Physical exercise improves motor performance in individuals with Parkinson's disease and elevates mood in those with depression. Although underlying factors have not been identified, clues arise from previous studies showing a link between cognitive benefits of exercise and increases in brain-derived neurotrophic factor (BDNF). Here, we investigated the influence of voluntary wheel-running exercise on BDNF levels in the striatum of young male wild-type (WT) mice, and on the striatal release of a key motor-system transmitter, dopamine (DA). Mice were allowed unlimited access to a freely rotating wheel (runners) or a locked wheel (controls) for 30 d. Electrically evoked DA release was quantified in ex vivo corticostriatal slices from these animals using fast-scan cyclic voltammetry. We found that exercise increased BDNF levels in dorsal striatum (dStr) and increased DA release in dStr and in nucleus accumbens core and shell. Increased DA release was independent of striatal acetylcholine (ACh), and persisted after a week of rest. We tested a role for BDNF in the influence of exercise on DA release using mice that were heterozygous for BDNF deletion (BDNF+/-). In contrast to WT mice, evoked DA release did not differ between BDNF+/- runners and controls. Complementary pharmacological studies using a tropomyosin receptor kinase B (TrkB) agonist in WT mouse slices showed that TrkB receptor activation also increased evoked DA release throughout striatum in an ACh-independent manner. Together, these data support a causal role for BDNF in exercise-enhanced striatal DA release and provide mechanistic insight into the beneficial effects of exercise in neuropsychiatric disorders, including Parkinson's, depression, and anxiety.SIGNIFICANCE STATEMENT Exercise has been shown to improve movement and cognition in humans and rodents. Here, we report that voluntary exercise for 30 d leads to an increase in evoked DA release throughout the striatum and an increase in BDNF in the dorsal (motor) striatum. The increase in DA release appears to require BDNF, indicated by the absence of DA release enhancement with running in BDNF+/- mice. Activation of BDNF receptors using a pharmacological agonist was also shown to boost DA release. Together, these data support a necessary and sufficient role for BDNF in exercise-enhanced DA release and provide mechanistic insight into the reported benefits of exercise in individuals with dopamine-linked neuropsychiatric disorders, including Parkinson's disease and depression.

The immunology of Parkinson's disease

Parkinson’s disease (PD) is the second most common neurodegenerative disorder which affects 6.1 million people worldwide. The neuropathological hallmarks include the loss of dopaminergic neurons in the substantia nigra, the presence of Lewy bodies and Lewy neurites caused by α-synuclein aggregation, and neuroinflammation in the brain. The prodromal phase happens years before the onset of PD during which time many patients show gastro-intestinal symptoms. These symptoms are in support of Braak’s theory and model where pathological α‐synuclein propagates from the gut to the brain. Importantly, immune responses play a determinant role in the pathogenesis of Parkinson’s disease. The innate immune responses triggered by microglia can cause neuronal death and disease progression. In addition, T cells infiltrate into the brains of PD patients and become involved in the adaptive immune responses. Interestingly, α‐synuclein is associated with both innate and adaptive immune responses by directly interacting with microglia and T cells. Here, we give a detailed review of the immunobiology of Parkinson’s disease, focusing on the role α-synuclein in the gut-brain axis hypothesis, the innate and adaptive immune responses involved in the disease, and current treatments.

Treatment initiation for parkinson’s disease in Australia 2013–2018: a nation-wide study

Background

Guidelines highlight the importance of an individualized approach to treatment initiation for Parkinson’s disease. Our aim was to investigate initiation of anti-Parkinson medication in Australia from 2013–2018, and to determine factors predicting choice of initial treatment.

Methods

Cohort of new-users (N = 4,887) of anti-Parkinson medication aged ≥ 40 years were identified from a 10% random representative sample of national medication dispensing data from July-2013 to June-2018. Changes in treatment initiation were examined across the whole cohort and stratified by age and sex.

Results

Treatment initiation was most frequent with levodopa followed by non-ergot dopamine agonists (DAs) and anticholinergics. Two thirds initiated with levodopa across the study period. Initiation with non-ergot DAs increased from 22 to 27% (rate ratio, RR 1.23, 95% confidence interval, CI 1.02–1.47) and initiation with anticholinergics decreased from 6.9% to 2.4% (RR 0.34, 95% CI 0.21–0.55) from 2013–2018. Among persons aged ≥ 65 years, one third of women and one fourth of men initiated on levodopa. Among women aged < 65 years, rates of treatment initiation with DAs (37%) and levodopa (37%) were similar in 2013/2014 but initiation with DA exceeded levodopa thereafter. Among men aged < 65 years, treatment initiation with levodopa (44%-49%) remained more frequent than initiation with DAs (29%-32%) throughout the study period.

Conclusions

Treatment initiation with levodopa was most frequent among persons aged ≥ 65 years, consistent with current guidelines. Whilst the value of levodopa sparing strategies is unclear, treatment initiation with DA has become increasingly common relative to levodopa among women but not among men aged < 65 years.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03095-3.

The role of Tumour Necrosis Factor in neuroinflammation associated with Parkinson's disease and targeted therapies

Neurodegenerative disorders Parkinson's disease is a progressive neurodegenerative disorder associated with neuroinflammatory responses that lead to the neurodegeneration of the dopaminergic neurons. These neuroinflammatory mechanisms involve various cytokines produced by the activated glial cells. Tumour Necrosis factor α (TNF α) is one of the major mediators of the neuroinflammation associated with neurodegeneration. TNF α has a dual role of neuroprotection and neurotoxicity in the brain. The effective pathways of TNF involve various signalling pathways transduced by the receptors TNFR1 and TNFR2. Effective therapeutic strategies have been produced targeting the neurotoxic behaviour of the Tumour Necrosis Factor and the associated neurodegeneration which includes the use of Dominant Negative Tumour Necrosis Factor (DN-TNF) inhibitors like XENP 345 and XPro®1595 and peroxisome proliferator receptor gamma (PPAR-γ) agonists.

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.

Alterations in Self-Aggregating Neuropeptides in Cerebrospinal Fluid of Patients with Parkinsonian Disorders

Background: Parkinson’s disease (PD), progressive supranuclear palsy (PSP), and multiple system atrophy (MSA) present with similar movement disorder symptoms but distinct protein aggregates upon pathological examination. Objective: Discovery and validation of candidate biomarkers in parkinsonian disorders for differential diagnosis of subgroup molecular etiologies. Methods: Untargeted liquid chromatography (LC)-mass spectrometry (MS) proteomics was used for discovery profiling in cerebral spinal fluid (CSF) followed by LC-MS/MS based multiple reaction monitoring for validation of candidates. We compared clinical variation within the parkinsonian cohort including PD subgroups exhibiting tremor dominance (TD) or postural instability gait disturbance and those with detectable leukocytes in CSF. Results: We have identified candidate peptide biomarkers and validated related proteins with targeted quantitative multiplexed assays. Dopamine-drug naïve patients at first diagnosis exhibit reduced levels of signaling neuropeptides, chaperones, and processing proteases for packaging of self-aggregating peptides into dense core vesicles. Distinct patterns of biomarkers were detected in the parkinsonian disorders but were not robust enough to offer a differential diagnosis. Different biomarker changes were detected in male and female patients with PD. Subgroup specific candidate biomarkers were identified for TD PD and PD patients with leukocytes detected in CSF. Conclusion: PD, MSA, and PSP exhibit overlapping as well as distinct protein biomarkers that suggest specific molecular etiologies. This indicates common sensitivity of certain populations of selectively vulnerable neurons in the brain, and distinct therapeutic targets for PD subgroups. Our report validates a decrease in CSF levels of self-aggregating neuropeptides in parkinsonian disorders and supports the role of native amyloidogenic proteins in etiologies of neurodegenerative diseases.

Baseline Differences in Long-term Survivors and Nonsurvivors of the Colorado/Columbia Fetal Implant Trial

OBJECTIVE

This study is based on long-term follow-up of participants in a randomized double-blind sham surgery-controlled trial (1995-1999) designed to determine the effectiveness of implantation of human embryonic mesencephalic tissue containing dopamine neuron precursors into the brains of patients with advanced Parkinson's disease (PD). We investigated differences between long-term survivors and nonsurvivors at baseline in order to contribute to information regarding optimal patient selection for upcoming stem cell trials.

METHOD

Forty participants were randomly assigned to receive either neural implantation or sham surgery. Thirty-four patients who ultimately received the implant were followed periodically with the most recent assessment occurring in 2015-2016. Demographic information, neurological measures, positron emission tomography (PET) imaging, neuropsychological assessments, and a personality assessment were included in the current analyses. T-tests were used to compare survivors and nonsurvivors. Logistic regression analyses examined predictors of survivorship.

RESULTS

Five of six survivors were female. They were younger than nonsurvivors (p = .03) and more neuropsychologically "intact" across a broad range of cognitive areas (significance levels ranged from <.001 to .045). There were no differences between survivors and nonsurvivors off medications at baseline on neurological or PET assessments. Survivors reported more "Openness to Experience" (p = .004) than nonsurvivors. Using empirically derived predictor variables, results of logistic regression analyses indicated that Animal Naming (cognitive task) and Openness to Experience (personality variable) were the strongest predictors of survivorship.

CONCLUSIONS

Variables to consider when selecting participants for future cell-based therapies include being "intact" neuropsychologically, level of Openness to Experience, younger age, and inclusion of women.

Demystifying the Neuroprotective Role of Neuropeptides in Parkinson's Disease: A Newfangled and Eloquent Therapeutic Perspective

Parkinson's disease (PD) refers to one of the eminently grievous, preponderant, tortuous nerve-cell-devastating ailments that markedly impacts the dopaminergic (DArgic) nerve cells of the midbrain region, namely the substantia nigra pars compacta (SN-PC). Even though the exact etiopathology of the ailment is yet indefinite, the existing corroborations have suggested that aging, genetic predisposition, and environmental toxins tremendously influence the PD advancement. Additionally, pathophysiological mechanisms entailed in PD advancement encompass the clumping of α-synuclein inside the lewy bodies (LBs) and lewy neurites, oxidative stress, apoptosis, neuronal-inflammation, and abnormalities in the operation of mitochondria, autophagy lysosomal pathway (ALP), and ubiquitin-proteasome system (UPS). The ongoing therapeutic approaches can merely mitigate the PD-associated manifestations, but until now, no therapeutic candidate has been depicted to fully arrest the disease advancement. Neuropeptides (NPs) are little, protein-comprehending additional messenger substances that are typically produced and liberated by nerve cells within the entire nervous system. Numerous NPs, for instance, substance P (SP), ghrelin, neuropeptide Y (NPY), neurotensin, pituitary adenylate cyclase-activating polypeptide (PACAP), nesfatin-1, and somatostatin, have been displayed to exhibit consequential neuroprotection in both in vivo and in vitro PD models via suppressing apoptosis, cytotoxicity, oxidative stress, inflammation, autophagy, neuronal toxicity, microglia stimulation, attenuating disease-associated manifestations, and stimulating chondriosomal bioenergetics. The current scrutiny is an effort to illuminate the neuroprotective action of NPs in various PD-experiencing models. The authors carried out a methodical inspection of the published work procured through reputable online portals like PubMed, MEDLINE, EMBASE, and Frontier, by employing specific keywords in the subject of our article. Additionally, the manuscript concentrates on representing the pathways concerned in bringing neuroprotective action of NPs in PD. In sum, NPs exert substantial neuroprotection through regulating paramount pathways indulged in PD advancement, and consequently, might be a newfangled and eloquent perspective in PD therapy.

Neuroglial Senescence, α-Synucleinopathy, and the Therapeutic Potential of Senolytics in Parkinson’s Disease

Parkinson’s disease (PD) is the most common movement disorder and the second most prevalent neurodegenerative disease after Alzheimer’s disease. Despite decades of research, there is still no cure for PD and the complicated intricacies of the pathology are still being worked out. Much of the research on PD has focused on neurons, since the disease is characterized by neurodegeneration. However, neuroglia has become recognized as key players in the health and disease of the central nervous system. This review provides a current perspective on the interactive roles that α-synuclein and neuroglial senescence have in PD. The self-amplifying and cyclical nature of oxidative stress, neuroinflammation, α-synucleinopathy, neuroglial senescence, neuroglial chronic activation and neurodegeneration will be discussed. Finally, the compelling role that senolytics could play as a therapeutic avenue for PD is explored and encouraged.

Contributions and Limitations of Mitochondria-Targeted and Non-Targeted Antioxidants in the Treatment of Parkinsonism: an Updated Review

As conventional therapeutics can only treat the symptoms of Parkinson's disease (PD), major focus of research in recent times is to slow down or prevent the progression of neuronal degeneration in PD. Non-targeted antioxidants have been an integral part of the conventional therapeutics regimen; however, their importance have lessened over time because of their controversial outcomes in clinical PD trials. Inability to permeate and localize within the mitochondria remains the main drawback on the part of non-targeted antioxidants inspite of possessing free radical scavenging properties. In contrast, mitochondrial-targeted antioxidants (MTAs), a special class of compounds have emerged having high advantages over non-targeted antioxidants by virtue of efficient pharmacokinetics and better absorption rate with capability to localize many fold inside the mitochondrial matrix. Preclinical experimentations indicate that MTAs have the potential to act as better alternatives compared to conventional non-targeted antioxidants in treating PD; however, sufficient clinical trials have not been conducted to investigate the efficacies of MTAs in treating PD. Controversial clinical outcomes on the part of non-targeted antioxidants and lack of clinical trials involving MTAs have made it difficult to go ahead with a direct comparison and in turn have slowed down the progress of development of safer and better alternate strategies in treating PD. This review provides an insight on the roles MTAs and non-targeted antioxidants have played in the treatment of PD till date in preclinical and clinical settings and discusses about the limitations of mitochondria-targeted and non-targeted antioxidants that can be resolved for developing effective strategies in treating Parkinsonism.

Gender differences in progressive supranuclear palsy

The gender differences in progressive supranuclear palsy (PSP) are not extensively studied. The objective of this study was to determine the gender differences in the phenotypic expression and progression in PSP. We did a retrospective review of medical records of patients diagnosed with PSP over a 21-year period. The interval between disease onset and attainment of the five clinical disability milestones namely wheel chair dependency, unintelligible speech, severe dysphagia, severe cognitive impairment and urinary catheterization was used to determine the progression. Data was analysed from the case records of 334 patients with PSP. 209 patients (62.2%) were male and 125 (37.4%) among the patients were women (male:female ratio = 1.6:1). Males had older age at onset with longer duration of illness at time of presentation. Tremors were more common, PSP-P phenotype was more frequent and time to attain wheelchair dependency was earlier in males. Falls within 1 year of disease onset, apathy and executive dysfunction were more frequent and time to attain unintelligible speech, severe dysphagia and cognitive impairment were earlier in females. This study in a large cohort of clinically diagnosed cases of PSP has showed that gender differences exist in PSP in terms of clinical characteristics, progression of the disease.

Aromatase inhibitors and the incidence of Parkinson disease: A population-based cohort study

BACKGROUND

Current guidelines recommend the treatment of hormone receptor-positive breast cancer with aromatase inhibitors (AIs) and tamoxifen in the adjuvant setting. Some observational studies have raised concerns that tamoxifen may be associated with an increased risk of Parkinson disease (PD). However, no studies have directly compared the risk of PD between AIs and tamoxifen in women diagnosed with breast cancer.

METHODS

Using the UK Clinical Practice Research Datalink, the authors assembled a cohort of women newly diagnosed with breast cancer and newly treated with either AIs or tamoxifen between January 1, 1995, and December 31, 2017. Patients were followed 1 year after treatment initiation (ie, a 1-year lag) until an incident diagnosis of PD or were censored at death from any cause, the date of transfer out of the practice, or the end of the study period (December 31, 2018). Cox proportional hazards models with inverse probability of treatment weights were used to estimate weighted hazard ratios (HRs) and 95% confidence intervals (CIs) for PD comparing AIs with tamoxifen and accounting for more than 30 confounders.

RESULTS

In all, 30,140 women with nonmetastatic breast cancer were identified: 13,838 initiated AIs, and 16,302 initiated tamoxifen. Compared with tamoxifen, AIs were not associated with an increased risk of PD (HR, 0.94; 95% CI, 0.60-1.47). Consistent results were observed across all secondary and sensitivity analyses.

CONCLUSIONS

In this large observational study, the use of AIs, in comparison with tamoxifen, was not associated with an increased risk of PD in women diagnosed with nonmetastatic breast cancer in a real-world setting.

LAY SUMMARY

Previous studies have indicated that tamoxifen may increase the risk of Parkinson disease in the treatment of breast cancer. However, no studies have directly compared the risk of Parkinson disease between aromatase inhibitors and tamoxifen. This study included 30,140 women diagnosed with breast cancer and treated with aromatase inhibitors or tamoxifen. Overall, compared with tamoxifen, aromatase inhibitors were not associated with an increased risk of Parkinson disease in women diagnosed with breast cancer. This study provides an important addition to the comparative safety profile of aromatase inhibitors and tamoxifen in the treatment of breast cancer.

Restoration and targeting of aberrant neurotransmitters in Parkinson's disease therapeutics

Neurotransmitters are considered as a fundamental regulator in the process of neuronal growth, differentiation and survival. Parkinson's Disease (PD) occurs due to extensive damage of dopamine-producing neurons; this causes dopamine deficits in the midbrain, followed by the alternation of various other neurotransmitters (glutamate, GABA, serotonin, etc.). It has been observed that fluctuation of neurotransmission in the basal ganglia exhibits a great impact on the pathophysiology of PD. Dopamine replacement therapy, such as the use of L-DOPA, can increase the dopamine level, but it majorly ameliorates the motor symptoms and is also associated with long-term complications (for e.g., LID). While the non-dopaminergic system can efficiently target non-motor symptoms, for instance, the noradrenergic system regulates the synthesis of BDNF via the MAPK pathway, which is important in learning and memory. Herein, we briefly discuss the role of different neurotransmitters, implementation of neurotransmitter receptors in PD. We also illustrate the recent advances of neurotransmitter-based drugs, which are currently under in vivo and clinical studies. Reinstating normal neurotransmitter levels has been believed to be advantageous in the treatment of PD. Thus, there is an increasing demand for drugs that can specifically target the neurotransmission system and reinstate the normal levels of neurotransmitters, which might prevent or delay neurodegeneration in PD.

Trends in Prevalence Cases and Disability-Adjusted Life-Years of Parkinson's disease: Findings from the Global Burden of Disease Study 2019

BACKGROUND

Parkinson's disease is a common, age-related progressive neurodegenerative disorder with considerable socioeconomic burdens, although the studies in incremental burdens to the disease' rapid growth are incomplete and lag behind. We aim to assess global burdens of Parkinson's disease based on a public database online.

METHODS

Based on the Global Burden of Disease, Injuries, and Risk Factors Study, we screened a range of indicators including prevalence cases, disability-adjusted life-years (DALY), age-standardized prevalence rates (ASPR) and age-standardized DALY (ASDR). The Join point regression was used to assess the indicators, wherein the ASPR and the ASDR were referred to temporal trends for burdens of Parkinson's disease.

RESULTS

Prevalence cases of global Parkinson's disease were on the rise for 30 years, with an increase of 155.51% during 1990-2019. Temporal trend of ASDRs was on the rise during 1990-2002 but in decline during 2002-2019. The ASPRs had a turning point in 2017 and a decline during 2017-2019 (APC (annual percentage changes) =-0.51%, P > 0.05). China, India, the United States, Japan and Germany shared the five highest prevalence cases and DALYs in 2019. Socio-demographic Index (SDI) was in relation to a significantly positive ASPR (R=0.61, P < 0.001) but not a significantly negative ASDR (R=-0.044, P=0.53), respectively.

CONCLUSIONS

In this study, a range of indicators for global burdens of Parkinson's disease were on the rise during 1990-2019. Tremendous efforts should be in place to prevent Parkinson's disease, especially among the populations of males, with advanced ages, in East Asia, and in regions with high SDI.

Intake of Flavonoids and Flavonoid-Rich Foods and Mortality Risk Among Individuals With Parkinson Disease: A Prospective Cohort Study

BACKGROUND AND OBJECTIVES

Although flavonoids have the potential to exert neuroprotective benefits, evidence of their role in improving survival rates among individuals with Parkinson disease (PD) remains lacking. We aimed to prospectively study the association between prediagnosis and postdiagnosis flavonoid intakes and risk of mortality among individuals with PD identified from 2 large ongoing cohorts of US men and women.

METHODS

Included in the current analysis were 599 women from the Nurses' Health Study and 652 men from the Health Professionals Follow-Up Study who were newly diagnosed with PD during follow-up. Dietary intakes of total flavonoid and its subclasses, together with major flavonoid-rich foods (tea, apples, berries, orange and orange juice, and red wine), were repeatedly assessed with a validated food frequency questionnaire every 4 years. Mortality was ascertained via the National Death Index and state vital statistics records.

RESULTS

We documented 944 deaths during 32 to 34 years of follow-up. A higher total flavonoid intake before PD diagnosis was associated with a lower future risk for all-cause mortality in men (hazard ratio [HR] comparing 2 extreme quartiles 0.53, 95% confidence interval [CI] 0.39, 0.71; p for trend < 0.001) but not in women (HR 0.93, 95% CI 0.68, 1.28; p for trend = 0.69) after adjustment for age, smoking status, total energy intake, and other covariates. The pooled HR comparing the extreme quartiles was 0.70 (95% CI 0.40, 1.22; p for trend = 0.25) with significant heterogeneity (p = 0.01). For flavonoid subclasses, the highest quartile of anthocyanins, flavones, and flavan-3-ols intakes before diagnosis had a lower mortality risk compared to the lowest quartile (pooled HR 0.66, 0.78, and 0.69, respectively; p < 0.05 for all); for berries and red wine, participants consuming ≥3 servings per week had a lower risk (pooled HR 0.77, 95% CI 0.58, 1.02; and pooled HR 0.68, 95% CI 0.51, 0.91, respectively) compared to <1 serving per month. After PD diagnosis, greater consumptions of total flavonoid, subclasses including flavonols, anthocyanins, flavan-3-ols, and polymers, and berries and red wine were associated with lower mortality risk (p < 0.05 for all).

DISCUSSION

Among individuals with PD, higher consumption of flavonoids, especially anthocyanins and flavan-3-ols, and flavonoid-rich food such as berries and red wine was likely to be associated with a lower risk of mortality.

Hormones and Sex-Specific Medicine in Human Physiopathology

A prodigious increment of scientific evidence in both preclinical and clinical studies is narrowing a major gap in knowledge regarding sex-specific biological responses observed in numerous branches of clinical practices. Some paradigmatic examples include neurodegenerative and mental disorders, immune-related disorders such as pathogenic infections and autoimmune diseases, oncologic conditions, and cardiovascular morbidities. The male-to-female proportion in a population is expressed as sex ratio and varies eminently with respect to the pathophysiology, natural history, incidence, prevalence, and mortality rates. The factors that determine this scenario incorporate both sex-associated biological differences and gender-dependent sociocultural issues. A broad narrative review focused on the current knowledge about the role of hormone regulation in gender medicine and gender peculiarities across key clinical areas is provided. Sex differences in immune response, cardiovascular diseases, neurological disorders, cancer, and COVID-19 are some of the hints reported. Moreover, gender implications in occupational health and health policy are offered to support the need for more personalized clinical medicine and public health approaches to achieve an ameliorated quality of life of patients and better outcomes in population health.

Sex-based differences in histology, staging, and prognosis among 2983 gastric cancer surgery patients

BACKGROUND

Few studies have been conducted on sex differences in the incidence, pathophysiology, and prognosis of gastric cancer (GC).

AIM

To analyze the differences in GC characteristics according to sex in patients who underwent surgical treatment for GC.

METHODS

A total of 2983 patients diagnosed with gastric adenocarcinoma who received surgical treatment at the Seoul National University Bundang Hospital between 2003 and 2017 were included. Baseline clinicopathological characteristics, histologic type of GC, overall and GC-specific survival rates, and associated risk factors were analyzed.

RESULTS

Among the 2983 patients, 2005 (67.2%) and 978 (32.8%) were males and females, respectively. The average age of the female group (59.36 years) was significantly younger than that of the male group (61.66 years; P < 0.001). Cancer of the gastric body (P < 0.001) and diffuse-type histology (P < 0.001) were more common in females than in males. This trend was more prominent in females younger than 60 years of age, with a significantly higher proportion of diffuse-type cancer than in the male group. Regardless of sex, diffuse-type GC was more common in younger patients, and the proportion of intestinal-type GC increased with age. The overall survival rate was significantly higher in females (P < 0.001). However, this difference disappeared for GC-specific survival (P = 0.168), except for the poor GC-specific survival rate in advanced-stage cancer (stage III or above) in females (P = 0.045). The risk factors for GC-related mortality were older age, upper location of GC, and diffuse- or mixed-type histology. In terms of comorbidities, more males died from diseases other than GC, including other malignancies such as lung cancer, hepatocellular carcinoma, and pancreatic cancer, and respiratory diseases such as interstitial lung disease and chronic obstructive pulmonary disease, while there were relatively more cardiovascular or cerebrovascular deaths in females.

CONCLUSION

Sex-based differences in GC were observed in clinicopathological features, including age at diagnosis, tumor location, histologic type, survival rate, and comorbidities.

Parkinson's disease and cancer: a systematic review and meta-analysis on the influence of lifestyle habits, genetic variants, and gender

PURPOSE

The relationship between Parkinson's disease (PD) and cancer has been debated. Gender and genetic influences on cancer development in PD is unclear.

METHODS

Using QUOROM guidelines, we conducted a systematic review and meta-analysis on potential clinical and genetic factors influencing the PD and subsequent cancer relationship. English articles published in PubMed, Web of Science, and SCOPUS from 2010 to 30 August 2020 were considered for suitability.

RESULTS

Of 46 studies identified, fourteen satisfied the inclusion criteria and were further analysed. Unadjusted risk ratios (RR) and 95% confidence intervals were computed to determine the PD and cancer relationship. PD patients have decreased subsequent cancer risks (RR = 0.87, 95% CI = 0.81-0.93), reduced risks of colon, rectal, and colorectal cancer (RR = 0.77, 95% CI = 0.63-0.94), lung cancer (RR = 0.62, 95% CI = 0.48-0.80), and increased brain cancer (R = 1.48, 95% CI = 1.02-2.13) and melanoma risk (R = 1.76, 95% CI = 1.23-2.50). Compared to idiopathic PD, LRRK2-G2019S carriers had increased general cancer risks (RR = 1.26, 95% CI = 1.09-1.46), particularly brain (RR = 2.41, 95% CI = 1.06-5.50), breast (RR = 2.57, 95% CI = 1.19-5.58), colon (RR = 1.83, 95% CI = 1.13-2.99), and haematological cancers (RR = 2.05, 95% CI = 1.07-3.92). Female PD patients have decreased general cancer risks compared to male PD patients in this analysis (RR = 0.83, 95% CI = 0.69-0.98).

CONCLUSION

PD patients have reduced risks of colon, rectal, colorectal cancer and lung cancers and increased risks of brain cancer and melanoma. LRRK2-G2019S carriers have increased cancer risks, particularly brain, breast, colon and blood cancers. Female gender was associated with reduced risks. The role of ethnicity, comorbidities, and lifestyle habits on PD patients' subsequent cancer risk should be further investigated.