Non-motor symptoms in Parkinson's disease

Excitatory synaptic structural abnormalities produced by templated aggregation of α-syn in the basolateral amygdala

Parkinson's disease (PD) and Dementia with Lewy bodies (DLB) are characterized by neuronal α-synuclein (α-syn) inclusions termed Lewy Pathology, which are abundant in the amygdala. The basolateral amygdala (BLA), in particular, receives projections from the thalamus and cortex. These projections play a role in cognition and emotional processing, behaviors which are impaired in α-synucleinopathies. To understand if and how pathologic α-syn impacts the BLA requires animal models of α-syn aggregation. Injection of α-syn pre-formed fibrils (PFFs) into the striatum induces robust α-syn aggregation in excitatory neurons in the BLA that corresponds with reduced contextual fear conditioning. At early time points after aggregate formation, cortico-amygdala excitatory transmission is abolished. The goal of this project was to determine if α-syn inclusions in the BLA induce synaptic degeneration and/or morphological changes. In this study, we used C57BL/6 J mice injected bilaterally with PFFs in the dorsal striatum to induce α-syn aggregate formation in the BLA. A method was developed using immunofluorescence and three-dimensional reconstruction to analyze excitatory cortico-amygdala and thalamo-amygdala presynaptic terminals closely juxtaposed to postsynaptic densities. The abundance and morphology of synapses were analyzed at 6- or 12-weeks post-injection of PFFs. α-Syn aggregate formation in the BLA did not cause a significant loss of synapses, but cortico-amygdala and thalamo-amygdala presynaptic terminals and postsynaptic densities with aggregates of α-syn show increased volumes, similar to previous findings in human DLB cortex, and in non-human primate models of PD. Transmission electron microscopy showed that asymmetric synapses in mice with PFF-induced α-syn aggregates have reduced synaptic vesicle intervesicular distances, similar to a recent study showing phospho-serine-129 α-syn increases synaptic vesicle clustering. Thus, pathologic α-syn causes major alterations to synaptic architecture in the BLA, potentially contributing to behavioral impairment and amygdala dysfunction observed in synucleinopathies.

An update on novel and emerging therapeutic targets in Parkinson's disease

Parkinson's Disease (PD) remains a significant focus of extensive research aimed at developing effective therapeutic strategies. Current treatments primarily target symptom management, with limited success in altering the course of the disease. This shortfall underscores the urgent need for novel therapeutic approaches that can modify the progression of PD.This review concentrates on emerging therapeutic targets poised to address the underlying mechanisms of PD. Highlighted novel and emerging targets include Protein Abelson, Rabphilin-3 A, Colony Stimulating Factor 1-Receptor, and Apelin, each showing promising potential in preclinical and clinical settings for their ability to modulate disease progression. By examining recent advancements and outcomes from trials focusing on these targets, the review aims to elucidate their efficacy and potential as disease-modifying therapies.Furthermore, the review explores the concept of multi-target approaches, emphasizing their relevance in tackling the complex pathology of PD. By providing comprehensive insights into these novel targets and their therapeutic implications, this review aims to guide future research directions and clinical developments toward more effective treatments for PD and related neurodegenerative disorders.

Striosomes Target Nigral Dopamine-Containing Neurons via Direct-D1 and Indirect-D2 Pathways Paralleling Classic Direct-Indirect Basal Ganglia Systems

Balanced activity of canonical direct D1 and indirect D2 basal ganglia pathways is considered a core requirement for normal movement, and their imbalance is an etiologic factor in movement and neuropsychiatric disorders. We present evidence for a conceptually equivalent pair of direct-D1 and indirect-D2 pathways that arise from striatal projection neurons (SPNs) of the striosome compartment rather than from SPNs of the matrix, as do the canonical pathways. These S-D1 and S-D2 striosomal pathways target substantia nigra dopamine-containing neurons instead of basal ganglia motor output nuclei. They modulate movement oppositely to the modulation by the canonical pathways: S-D1 is inhibitory and S-D2 is excitatory. The S-D1 and S-D2 circuits likely influence motivation for learning and action, complementing and reorienting canonical pathway modulation. A major conceptual reformulation of the classic direct-indirect pathway model of basal ganglia function is needed, as well as reconsideration of the effects of D2-targeting therapeutic drugs.

Financial capability of people living with Parkinson's disease - A case-control study

Parkinson's disease (PD) is a neurodegenerative disorder affecting 1% of people older than 60 years. One of the abilities that seems vulnerable to the cognitive impairments associated with PD is financial capability. This explorative study aimed to evaluate the extent and type of problems in financial capability of people with PD without a diagnosis of dementia. Participants were 31 people with PD and 62 matched controls. Participants completed an extensive test-battery, including measures for financial capability and cognitive functioning. Compared to controls, the PD-group performed significantly poorer on two financial competence tasks and showed a comparable performance on the other financial capability measures. For 45% of the PD-group, cognitive test performance was indicative of mild cognitive impairment, yet no significant difference was observed in overall cognitive functioning between the PD and control group. In the total sample, only small or medium correlations were found between financial competence and cognition, and between financial capability and the contextual factors of income and financial experience. The findings suggest that in the earlier stages of PD, when cognitive impairments are relatively mild, some problems may be observed in financial competence, yet other domains of financial capability appear less affected. The absence of strong correlations between financial competence and overall cognitive functioning indicates that standard neuropsychological assessments seem inadequate to make financial capability determinations. By offering insight into the financial capability of people in the milder stages of PD, the findings of the present study may aid in the development and provision of tailored support.

The Effect of Neuronal CoQ10 Deficiency and Mitochondrial Dysfunction on a Rotenone-Induced Neuronal Cell Model of Parkinson's Disease

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder currently affecting the ageing population. Although the aetiology of PD has yet to be fully elucidated, environmental factors such as exposure to the naturally occurring neurotoxin rotenone has been associated with an increased risk of developing PD. Rotenone inhibits mitochondrial respiratory chain (MRC) complex I activity as well as induces dopaminergic neuronal death. The aim of the present study was to investigate the underlying mechanisms of rotenone-induced mitochondrial dysfunction and oxidative stress in an in vitro SH-SY5Y neuronal cell model of PD and to assess the ability of pre-treatment with Coenzyme Q10 (CoQ10) to ameliorate oxidative stress in this model. Spectrophotometric determination of the mitochondrial enzyme activities and fluorescence probe studies of reactive oxygen species (ROS) production was assessed. Significant inhibition of MRC complex I and II-III activities was observed, together with a significant loss of neuronal viability, CoQ10 status, and ATP synthesis. Additionally, significant increases were observed in intracellular and mitochondrial ROS production. Remarkably, CoQ10 supplementation was found to reduce ROS formation. These results have indicated mitochondrial dysfunction and increased oxidative stress in a rotenone-induced neuronal cell model of PD that was ameliorated by CoQ10 supplementation.

An Overview of Epigenetic Changes in the Parkinson's Disease Brain

Parkinson's disease is a progressive neurodegenerative disorder, predominantly of the motor system. Although some genetic components and cellular mechanisms of Parkinson's have been identified, much is still unknown. In recent years, emerging evidence has indicated that non-DNA-sequence variation (in particular epigenetic mechanisms) is likely to play a crucial role in the development and progression of the disease. Here, we present an up-to-date overview of epigenetic processes including DNA methylation, DNA hydroxymethylation, histone modifications and non-coding RNAs implicated in the brain of those with Parkinson's disease. We will also discuss the limitations of current epigenetic research in Parkinson's disease, the advantages of simultaneously studying genetics and epigenetics, and putative novel epigenetic therapies.

Navigating through the complexities of synucleinopathies: Insights into pathogenesis, heterogeneity, and future perspectives

The aggregation of alpha-synuclein (aSyn) represents a neuropathological hallmark observed in a group of neurodegenerative disorders collectively known as synucleinopathies. Despite their shared characteristics, these disorders manifest diverse clinical and pathological phenotypes. The mechanism underlying this heterogeneity is thought to be due to the diversity in the aSyn strains present across the diseases. In this perspective, we will explore recent findings on aSyn strains and discuss recent discoveries about Lewy bodies' composition. We further discuss the current hypothesis for aSyn spreading and emphasize the emerging biomarker field demonstrating promising results. A comprehension of these mechanisms holds substantial promise for future clinical applications. This understanding can pave the way for the development of personalized medicine strategies, specifically targeting the unique underlying causes of each synucleinopathy. Such advancements can revolutionize therapeutic approaches and significantly contribute to more effective interventions in the intricate landscape of neurodegenerative disorders.

Cortico-amygdala synaptic structural abnormalities produced by templated aggregation of α-synuclein

Parkinson's disease (PD) and Dementia with Lewy bodies (DLB) are characterized by neuronal α-synuclein (α-syn) inclusions termed Lewy Pathology, which are abundant in the amygdala. The basolateral amygdala (BLA), in particular, receives projections from the thalamus and cortex. These projections play a role in cognition and emotional processing, behaviors which are impaired in α-synucleinopathies. To understand if and how pathologic α-syn impacts the BLA requires animal models of α-syn aggregation. Injection of α-synuclein pre-formed fibrils (PFFs) into the striatum induces robust α-synuclein aggregation in excitatory neurons in the BLA that corresponds with reduced contextual fear conditioning. At early time points after aggregate formation, cortico-amygdala excitatory transmission is abolished. The goal of this project was to determine if α-syn inclusions in the BLA induce synaptic degeneration and/or morphological changes. In this study, we used C57BL/6J mice injected bilaterally with PFFs in the dorsal striatum to induce α-syn aggregate formation in the BLA. A method was developed using immunofluorescence and three-dimensional reconstruction to analyze excitatory cortico-amygdala and thalamo-amygdala presynaptic terminals closely juxtaposed to postsynaptic densities. The abundance and morphology of synapses were analyzed at 6- or 12-weeks post-injection of PFFs. α-Syn aggregate formation in the BLA did not cause a significant loss of synapses, but cortico-amygdala and thalamo-amygdala presynaptic terminals and postsynaptic densities with aggregates of α-synuclein show increased volumes, similar to previous findings in human DLB cortex, and in non-human primate models of PD. Transmission electron microscopy showed that PFF-injected mice showed reduced intervesicular distances similar to a recent study showing phospho-serine-129 α-synuclein increases synaptic vesicle clustering. Thus, pathologic α-synuclein causes major alterations to synaptic architecture in the BLA, potentially contributing to behavioral impairment and amygdala dysfunction observed in synucleinopathies.

Development of Midbrain Dopaminergic Neurons and the Advantage of Using hiPSCs as a Model System to Study Parkinson's Disease

Midbrain dopaminergic (mDA) neurons are significantly impaired in patients inflicted with Parkinson's disease (PD), subsequently affecting a variety of motor functions. There are four pathways through which dopamine elicits its function, namely, nigrostriatal, mesolimbic, mesocortical and tuberoinfundibular dopamine pathways. SHH and Wnt signalling pathways in association with favourable expression of a variety of genes, promotes the development and differentiation of mDA neurons in the brain. However, there is a knowledge gap regarding the complex signalling pathways involved in development of mDA neurons. hiPSC models have been acclaimed to be effective in generating complex disease phenotypes. These models mimic the microenvironment found in vivo thus ensuring maximum reliability. Further, a variety of therapeutic compounds can be screened using hiPSCs since they can be used to generate neurons that could carry an array of mutations associated with both familial and sporadic PD. Thus, culturing hiPSCs to study gene expression and dysregulation of cellular processes associated with PD can be useful in developing targeted therapies that will be a step towards halting disease progression.

State-dependent alteration of respiration in a rat model of Parkinson's disease

Parkinson's disease (PD) is the second most frequent neurodegenerative disorder. Besides major deficits in motor coordination, patients may also display sensory and cognitive impairments, which are often overlooked despite being inherently part of the PD symptomatology. Amongst those symptoms, respiration, a key mechanism involved in the regulation of multiple physiological and neuronal processes, appears to be altered. Importantly, breathing patterns are highly correlated with the animal's behavioral states. This raises the question of the potential impact of behavioral state on respiration deficits in PD. To answer this question, we first characterized the respiratory parameters in a neurotoxin-induced rat model of PD (6-OHDA) across three different vigilance states: sleep, quiet waking and exploration. We noted a significantly higher respiratory frequency in 6-OHDA rats during quiet waking compared to Sham rats. A higher respiratory amplitude was also observed in 6-OHDA rats during both quiet waking and exploration. No effect of the treatment was noted during sleep. Given the relation between respiration and olfaction and the presence of olfactory deficits in PD patients, we then investigated the odor-evoked sniffing response in PD rats, using an odor habituation/cross-habituation paradigm. No substantial differences were observed in olfactory abilities between the two groups, as assessed through sniffing frequency. These results corroborate the hypothesis that respiratory impairments in 6-OHDA rats are vigilance-dependent. Our results also shed light on the importance of considering the behavioral state as an impacting factor when analyzing respiration.

Oxidative Stress and Neurodegeneration: Insights and Therapeutic Strategies for Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative condition marked by the gradual deterioration of dopaminergic neurons in the substantia nigra. Oxidative stress has been identified as a key player in the development of PD in recent studies. In the first part, we discuss the sources of oxidative stress in PD, including mitochondrial dysfunction, dopamine metabolism, and neuroinflammation. This paper delves into the possibility of mitigating oxidative stress as a potential treatment approach for PD. In addition, we examine the hurdles and potential of antioxidant therapy, including the challenge of delivering antioxidants to the brain and the requirement for biomarkers to track oxidative stress in PD patients. However, even if antioxidant therapy holds promise, further investigation is needed to determine its efficacy and safety in PD treatment.

Common genetic risk for Parkinson's disease and dysfunction of the endo-lysosomal system

Parkinson's disease is a progressive neurological disorder, characterized by prominent movement dysfunction. The past two decades have seen a rapid expansion of our understanding of the genetic basis of Parkinson's, initially through the identification of monogenic forms and, more recently, through genome-wide association studies identifying common risk variants. Intriguingly, a number of cellular pathways have emerged from these analysis as playing central roles in the aetiopathogenesis of Parkinson's. In this review, the impact of data deriving from genome-wide analyses for Parkinson's upon our functional understanding of the disease will be examined, with a particular focus on examples of endo-lysosomal and mitochondrial dysfunction. The challenges of moving from a genetic to a functional understanding of common risk variants for Parkinson's will be discussed, with a final consideration of the current state of the genetic architecture of the disorder. This article is part of a discussion meeting issue 'Understanding the endo-lysosomal network in neurodegeneration'.

Suppression of presynaptic corticostriatal glutamate activity attenuates L-dopa-induced dyskinesia in 6-OHDA-lesioned Parkinson's disease mice

A common adverse effect of Parkinson's disease (PD) treatment is L-dopa-induced dyskinesia (LID). This condition results from both dopamine (DA)-dependent and DA-independent mechanisms, as glutamate inputs from corticostriatal projection neurons impact DA-responsive medium spiny neurons in the striatum to cause the dyskinetic behaviors. In this study, we explored whether suppression of presynaptic corticostriatal glutamate inputs might affect the behavioral and biochemical outcomes associated with LID. We first established an animal model in which 6-hydroxydopamine (6-OHDA)-lesioned mice were treated daily with L-dopa (10 mg/kg, i.p.) for 2 weeks; these mice developed stereotypical abnormal involuntary movements (AIMs). When the mice were pretreated with the NMDA antagonist, amantadine, we observed suppression of AIMs and reductions of phosphorylated ERK1/2 and NR2B in the striatum. We then took an optogenetic approach to manipulate glutamatergic activity. Slc17a6 (vGluT2)-Cre mice were injected with pAAV5-Ef1a-DIO-eNpHR3.0-mCherry and received optic fiber implants in either the M1 motor cortex or dorsolateral striatum. Optogenetic inactivation at either optic fiber implant location could successfully reduce the intensity of AIMs after 6-OHDA lesioning and L-dopa treatment. Both optical manipulation strategies also suppressed phospho-ERK1/2 and phospho-NR2B signals in the striatum. Finally, we performed intrastriatal injections of LDN 212320 in the dyskenesic mice to enhance expression of glutamate uptake transporter GLT-1. Sixteen hours after the LDN 212320 treatment, L-dopa-induced AIMs were reduced along with the levels of striatal phospho-ERK1/2 and phospho-NR2B. Together, our results affirm a critical role of corticostriatal glutamate neurons in LID and strongly suggest that diminishing synaptic glutamate, either by suppression of neuronal activity or by upregulation of GLT-1, could be an effective approach for managing LID.

Inflachromene ameliorates Parkinson's disease by targeting Nrf2-binding Keap1

Parkinson's disease (PD) is the most common neurodegenerative disease characterized by movement disorder. Despite current therapeutic efforts, PD progression and the loss of dopaminergic neurons in the substantia nigra remain challenging to prevent due to the complex and unclear molecular mechanism involved. We adopted a phenotype-based drug screening approach with neuronal cells to overcome these limitations. In this study, we successfully identified a small molecule with a promising therapeutic effect for PD treatment, called inflachromene (ICM), through our phenotypic screening strategy. Subsequent target identification using fluorescence difference in two-dimensional gel electrophoresis (FITGE) revealed that ICM ameliorates PD by targeting a specific form of Keap1. This interaction led to upregulating various antioxidants, including HO-1, NQO1, and glutathione, ultimately alleviating PD symptoms. Furthermore, ICM exhibited remarkable efficacy in inhibiting the loss of dopaminergic neurons and the activation of astrocytes and microglia, which are critical factors in PD pathology. Our findings suggest that the phenotypic approach employed in this study identified that ICM has potential for PD treatment, offering new hope for more effective therapeutic interventions in the future.

Computer Vision for Parkinson's Disease Evaluation: A Survey on Finger Tapping

Parkinson's disease (PD) is a progressive neurodegenerative disorder whose prevalence has steadily been rising over the years. Specialist neurologists across the world assess and diagnose patients with PD, although the diagnostic process is time-consuming and various symptoms take years to appear, which means that the diagnosis is prone to human error. The partial automatization of PD assessment and diagnosis through computational processes has therefore been considered for some time. One well-known tool for PD assessment is finger tapping (FT), which can now be assessed through computer vision (CV). Artificial intelligence and related advances over recent decades, more specifically in the area of CV, have made it possible to develop computer systems that can help specialists assess and diagnose PD. The aim of this study is to review some advances related to CV techniques and FT so as to offer insight into future research lines that technological advances are now opening up.

Axonal Lysosomal Assays for Characterizing the Effects of LRRK2 G2019S

The degeneration of axon terminals before the soma, referred to as "dying back", is a feature of Parkinson's disease (PD). Axonal assays are needed to model early PD pathogenesis as well as identify protective therapeutics. We hypothesized that defects in axon lysosomal trafficking as well as injury repair might be important contributing factors to "dying back" pathology in PD. Since primary human PD neurons are inaccessible, we developed assays to quantify axonal trafficking and injury repair using induced pluripotent stem cell (iPSC)-derived neurons with LRRK2 G2019S, which is one of the most common known PD mutations, and isogenic controls. We observed a subtle axonal trafficking phenotype that was partially rescued by a LRRK2 inhibitor. Mutant LRRK2 neurons showed increased phosphorylated Rab10-positive lysosomes, and lysosomal membrane damage increased LRRK2-dependent Rab10 phosphorylation. Neurons with mutant LRRK2 showed a transient increase in lysosomes at axotomy injury sites. This was a pilot study that used two patient-derived lines to develop its methodology; we observed subtle phenotypes that might correlate with heterogeneity in LRRK2-PD patients. Further analysis using additional iPSC lines is needed. Therefore, our axonal lysosomal assays can potentially be used to characterize early PD pathogenesis and test possible therapeutics.

Cannabidiol and brain function: current knowledge and future perspectives

Cannabidiol (CBD) is a naturally occurring non-psychoactive cannabinoid found in Cannabis sativa, commonly known as cannabis or hemp. Although currently available CBD products do not meet the safety standards of most food safety authorities to be approved as a dietary supplement or food additive, CBD has been gaining widespread attention in recent years due to its various potential health benefits. While primarily known for its therapeutic effects in managing epileptic seizures, psychosis, anxiety, (neuropathic) pain, and inflammation, CBD's influence on brain function has also piqued the interest of researchers and individuals seeking to enhance cognitive performance. The primary objective of this review is to gather, synthesize, and consolidate scientifically proven evidence on the impact of CBD on brain function and its therapeutic significance in treating neurological and mental disorders. First, basic background information on CBD, including its biomolecular properties and mechanisms of action is presented. Next, evidence for CBD effects in the human brain is provided followed by a discussion on the potential implications of CBD as a neurotherapeutic agent. The potential effectiveness of CBD in reducing chronic pain is considered but also in reducing the symptoms of various brain disorders such as epilepsy, Alzheimer's, Huntington's and Parkinson's disease. Additionally, the implications of using CBD to manage psychiatric conditions such as psychosis, anxiety and fear, depression, and substance use disorders are explored. An overview of the beneficial effects of CBD on aspects of human behavior, such as sleep, motor control, cognition and memory, is then provided. As CBD products remain largely unregulated, it is crucial to address the ethical concerns associated with their use, including product quality, consistency, and safety. Therefore, this review discusses the need for responsible research and regulation of CBD to ensure its safety and efficacy as a therapeutic agent for brain disorders or to stimulate behavioral and cognitive abilities of healthy individuals.

Effects of Manual Therapy on Parkinson's Gait: A Systematic Review

Manual therapy (MT) is commonly used in rehabilitation to deal with motor impairments in Parkinson's disease (PD). However, is MT an efficient method to improve gait in PD? To answer the question, a systematic review of clinical controlled trials was conducted. Estimates of effect sizes (reported as standard mean difference (SMD)) with their respective 95% confidence interval (95% CI) were reported for each outcome when sufficient data were available. If data were lacking, p values were reported. The PEDro scale was used for the quality assessment. Three studies were included in the review. MT improved Dynamic Gait Index (SMD = 1.47; 95% CI: 0.62, 2.32; PEDro score: 5/10, moderate level of evidence). MT also improved gait performances in terms of stride length, velocity of arm movements, linear velocities of the shoulder and the hip (p < 0.05; PEDro score: 2/10, limited level of evidence). There was no significant difference between groups after MT for any joint's range of motion during gait (p > 0.05; PEDro score: 6/10, moderate level of evidence). There is no strong level of evidence supporting the beneficial effect of MT to improve gait in PD. Further randomized controlled trials are needed to understand the impact of MT on gait in PD.

Neuroprotective effects of nanogold-based Ayurveda medicine Suvarna Bhasma against rotenone-induced Parkinson's-like model

BACKGROUND

Neurodegenerative diseases have been one of the major concerns for human health. Genetic and environmental factors are believed to be responsible for neuronal diseases such as Parkinson's disease, Alzheimer's disease, and Huntington's disease. It is difficult to restore normal nervous function after neurodegeneration; hence, prevention could be the best strategy against these diseases. Ayurved medicines such as Suvarna Bhasma (SB) have enormous potential to treat these neurological diseases.

AIM

The aim of this study is to examine the protective effect of SB against rotenone-induced Parkinson's-like model in zebrafish.

MATERIALS AND METHODS

In this study, we induced Parkinson's-like disease model in zebrafish by inducing it with rotenone (7 μg/L). We examined the behavioural, proteomics and dopamine alterations of rotenone induced zebrafish of SB pre-treated group as compared to the control group.

RESULTS

The behavioural experiments showed that due to rotenone exposure, Parkinson's-like behavioural abnormality was induced in zebrafish. However, because of SB treatment, this behavioural abnormality was reduced. The proteomics study of zebrafish brains clearly showed that the SB-treated group was not significantly affected due to rotenone exposure. However, in the SB non-treated group, expression of nine proteins that are linked to Parkinson's disease (gene name: sncgb, ywhae1, ywhah, uchl1, ywhaba, psma6a, ywhabl, ywhaqb, and ywhabb) were differentially expressed after rotenone exposure. Finally, prevention of dopamine alteration in SB-treated fish brains confirmed the protective action of SB against rotenone-induced Parkinson's-like model in zebrafish.

CONCLUSIONS

This study finds that Suvarna Bhasma has neuroprotective effects against Parkinson's-like disease model.

CBT for Generalized Anxiety Disorder in Parkinson's Disease: A Case Study

OBJECTIVES

To examine the use of cognitive behavioral therapy (CBT) in a case of co-occurring generalized anxiety disorder (GAD) and Parkinson's disease (PD).

METHODS

This case study refers to a male aged 75 years with a diagnosis of Idiopathic Parkinson's disease. It focuses on applying a CBT model to address the psychological difficulties with PD and GAD.

RESULTS

This case study reveals key aspects in presentation, diagnosis, and psychological treatment between PD and GAD, and is one of few studies published in this area.

CONCLUSIONS

Symptoms of anxiety in an older adult with PD decreased during a course of CBT. The implications of the treatment outcome of this study and further considerations of treatment plans for comorbid PD and anxiety have been discussed.

CLINICAL IMPLICATIONS

Using CBT could positively impact non-motor symptoms of Parkinson's, such as sleep difficulties and speech impediments. Using CBT for the catastrophic thinking and worry content in GAD seems to act as a complementary therapy for psychological/non-motor symptoms of PD.

Role of Autophagy and Mitophagy in Neurodegenerative Disorders

Autophagy is a self-destructive cellular process that removes essential metabolites and waste from inside the cell to maintain cellular health. Mitophagy is the process by which autophagy causes disruption inside mitochondria and the total removal of damaged or stressed mitochondria, hence enhancing cellular health. The mitochondria are the powerhouses of the cell, performing essential functions such as ATP (adenosine triphosphate) generation, metabolism, Ca2+ buffering, and signal transduction. Many different mechanisms, including endosomal and autophagosomal transport, bring these substrates to lysosomes for processing. Autophagy and endocytic processes each have distinct compartments, and they interact dynamically with one another to complete digestion. Since mitophagy is essential for maintaining cellular health and using genetics, cell biology, and proteomics techniques, it is necessary to understand its beginning, particularly in ubiquitin and receptor-dependent signalling in injured mitochondria. Despite their similar symptoms and emerging genetic foundations, Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS) have all been linked to abnormalities in autophagy and endolysosomal pathways associated with neuronal dysfunction. Mitophagy is responsible for normal mitochondrial turnover and, under certain physiological or pathological situations, may drive the elimination of faulty mitochondria. Due to their high energy requirements and post-mitotic origin, neurons are especially susceptible to autophagic and mitochondrial malfunction. This article focused on the importance of autophagy and mitophagy in neurodegenerative illnesses and how they might be used to create novel therapeutic approaches for treating a wide range of neurological disorders.

Stem Cell-Based Modeling Protocol for Parkinson's Disease

Parkinson's disease is a progressive neurodegenerative disorder, which is mainly characterized by unintended or uncontrollable body movements. Pathophysiologically, disturbances in the neurotransmission system of the brain like dopaminergic system and synaptic dysfunction are classified as top-rated causes of the onset of Parkinson's disease, which symptoms can be different according to the involvement of neurotransmission system type and the effect of the disease on the motor and non-motor systems. Although some pharmacological and non-pharmacological approaches have been applied to control and slow down the progression of the disease, a definitive cure has not yet been discovered. One of the factors involved in this issue is the lack of appropriate laboratory models to investigate the pathological mechanisms involved in the disease as well as various aspects of candidate drugs, which ultimately leads to the failure of drug discovery and development pipelines. To deal with these challenges, the application of stem cells, especially cellular reprogramming of somatic cells to human pluripotent stem cells, also known as induced pluripotent stem cells, has been able to promise a new chapter in the modeling of Parkinson's disease. Induced pluripotent stem cells have the stemness capability; therefore, they can differentiate into any type of cell such as nerve cells. Also, since these cells are obtained from the reprogramming of somatic cells in the patient's body, they maintain the patient's genetic content, which can play an important role in increasing the quality of disease modeling and the validity of the results of laboratory studies. Therefore, the procedure for modeling induced pluripotent stem cells for Parkinson's disease is explained in this chapter.

Safinamide for pain management in patients with Parkinson's disease

INTRODUCTION

Pain is often neglected in Parkinson's disease (PD), although it impacts most PD patients. While the mechanism of pain in PD is still being studied, various pharmacological, interventional, and alternative treatment options have been offered for pain relief. Safinamide, a recently approved drug for PD, has shown promising results in improving pain in patients with PD. Several clinical studies report changes in pain scores in PD patients treated with safinamide, but these have not been systematically summarized. Therefore, our main goal was to perform a systematic review and statistical analysis of relevant studies.

METHODS

A systematic search of studies was conducted using four databases: Pubmed, Cochrane Library, Google Scholar, and Scopus. The nine included randomized controlled trials did not provide sufficient data for a meta-analysis; therefore, we conducted a qualitative systematic review.

RESULTS

Our results suggest that safinamide at a daily dose of 100mg is more effective for treating PD pain than that of 50mg. Moreover, the reduction in fluctuation-related pain and pain from edema was more consistent when treated with safinamide compared to other PD pain types. We also attempted to suggest a mechanism of action for safinamide on pain processing in the brain, which should be explored in more detail in future studies.

CONCLUSION

Clinical evidence suggests that safinamide may be particularly beneficial for PD patients experiencing fluctuation-related pain and pain from edema, as these subtypes of pain showed greater improvement compared to other types of pain. Based on the findings of the included studies, safinamide appears to relieve the overall pain burden. However, the lack of sufficient data for conducting a meta-analysis highlights the need for future studies to report mean pain scores and their standard deviations.

Enhanced mTORC1 signaling and protein synthesis in pathologic α-synuclein cellular and animal models of Parkinson's disease

Pathologic α-synuclein plays an important role in the pathogenesis of α-synucleinopathies such as Parkinson's disease (PD). Disruption of proteostasis is thought to be central to pathologic α-synuclein toxicity; however, the molecular mechanism of this deregulation is poorly understood. Complementary proteomic approaches in cellular and animal models of PD were used to identify and characterize the pathologic α-synuclein interactome. We report that the highest biological processes that interacted with pathologic α-synuclein in mice included RNA processing and translation initiation. Regulation of catabolic processes that include autophagy were also identified. Pathologic α-synuclein was found to bind with the tuberous sclerosis protein 2 (TSC2) and to trigger the activation of the mammalian target of rapamycin (mTOR) complex 1 (mTORC1), which augmented mRNA translation and protein synthesis, leading to neurodegeneration. Genetic and pharmacologic inhibition of mTOR and protein synthesis rescued the dopamine neuron loss, behavioral deficits, and aberrant biochemical signaling in the α-synuclein preformed fibril mouse model and Drosophila transgenic models of pathologic α-synuclein-induced degeneration. Pathologic α-synuclein furthermore led to a destabilization of the TSC1-TSC2 complex, which plays an important role in mTORC1 activity. Constitutive overexpression of TSC2 rescued motor deficits and neuropathology in α-synuclein flies. Biochemical examination of PD postmortem brain tissues also suggested deregulated mTORC1 signaling. These findings establish a connection between mRNA translation deregulation and mTORC1 pathway activation that is induced by pathologic α-synuclein in cellular and animal models of PD.

Clinical biomarkers for Lewy body diseases

Synucleinopathies are a group of neurodegenerative disorders characterized by pathologic aggregates of neural and glial α-synuclein (α-syn) in the form of Lewy bodies (LBs), Lewy neurites, and cytoplasmic inclusions in both neurons and glia. Two major classes of synucleinopathies are LB disease and multiple system atrophy. LB diseases include Parkinson's disease (PD), PD with dementia, and dementia with LBs. All are increasing in prevalence. Effective diagnostics, disease-modifying therapies, and therapeutic monitoring are urgently needed. Diagnostics capable of differentiating LB diseases are based on signs and symptoms which might overlap. To date, no specific diagnostic test exists despite disease-specific pathologies. Diagnostics are aided by brain imaging and cerebrospinal fluid evaluations, but more accessible biomarkers remain in need. Mechanisms of α-syn evolution to pathologic oligomers and insoluble fibrils can provide one of a spectrum of biomarkers to link complex neural pathways to effective therapies. With these in mind, we review promising biomarkers linked to effective disease-modifying interventions.

Impact of deep brain stimulation (DBS) on olfaction in Parkinson's disease: Clinical features and functional hypotheses

Deep brain stimulation (DBS) is a surgical therapy typically applied in Parkinson's disease (PD). The efficacity of DBS on the control of motor symptoms in PD is well grounded while the efficacity on non-motor symptoms is more controversial, especially on olfactory disorders (ODs). The present review shows that DBS does not improve hyposmia but can affect positively identification/discrimination scores in PD. The functional hypotheses suggest complex mechanisms in terms of cerebral connectivity and neurogenesis process which could act indirectly on the olfactory bulb and olfactory pathways related to specific cognitive olfactory tasks. The functional hypotheses also suggest complex mechanisms of cholinergic neurotransmitter interactions involved in these pathways. Finally, the impact of DBS on general cognitive functions in PD could also be beneficial to identification/discrimination tasks in PD.

Safety and feasibility of faecal microbiota transplantation for patients with Parkinson's disease: a protocol for a self-controlled interventional donor-FMT pilot study

INTRODUCTION

Experimental studies suggest a role of gut microbiota in the pathophysiology of Parkinson's disease (PD) via the gut-brain axis. The gut microbiota can also influence the metabolism of levodopa, which is the mainstay of treatment of PD. Therefore, modifying the gut microbiota by faecal microbiota transplantation (FMT) could be a supportive treatment strategy.

METHODS AND ANALYSIS

We have developed a study protocol for a single-centre, prospective, self-controlled, interventional, safety and feasibility donor-FMT pilot study with randomisation and double-blinded allocation of donor faeces. The primary objectives are feasibility and safety of FMT in patients with PD. Secondary objectives include exploring whether FMT leads to alterations in motor complications (fluctuations and dyskinesias) and PD motor and non-motor symptoms (including constipation), determining alterations in gut microbiota composition, assessing donor-recipient microbiota similarities and their association with PD symptoms and motor complications, evaluating the ease of the study protocol and examining FMT-related adverse events in patients with PD. The study population will consist of 16 patients with idiopathic PD that use levodopa and experience motor complications. They will receive FMT with faeces from one of two selected healthy human donors. FMT will be administered via a gastroscope into the duodenum, after treatment with oral vancomycin, bowel lavage and domperidone. There will be seven follow-up moments during 12 months.

ETHICS AND DISSEMINATION

This study was approved by the Medical Ethical Committee Leiden Den Haag Delft (ref. P20.087). Study results will be disseminated through publication in peer-reviewed journals and international conferences.

TRIAL REGISTRATION NUMBER

International Clinical Trial Registry Platform: NL9438.

Pink1-/- Rats Demonstrate Swallowing and Gastrointestinal Dysfunction in a Model of Prodromal Parkinson Disease

Early motor and non-motor signs of Parkinson disease (PD) include dysphagia, gastrointestinal dysmotility, and constipation. However, because these often manifest prior to formal diagnosis, the study of PD-related swallow and GI dysfunction in early stages is difficult. To overcome this limitation, we used the Pink1-/- rat, a well-established early-onset genetic rat model of PD to assay swallowing and GI motility deficits. Thirty male rats were tested at 4 months (Pink1-/- = 15, wildtype (WT) control = 15) and 6 months (Pink1-/- = 7, WT = 6) of age; analogous to early-stage PD in humans. Videofluoroscopy of rats ingesting a peanut-butter-barium mixture was used to measure mastication rate and oropharyngeal and pharyngoesophageal bolus speeds. Abnormal swallowing behaviors were also quantified. A second experiment tracked barium contents through the stomach, small intestine, caecum, and colon at hours 0-6 post-barium gavage. Number and weight of fecal emissions over 24 h were also collected. Compared to WTs, Pink1-/- rats showed slower mastication rates, slower pharyngoesophageal bolus speeds, and more abnormal swallowing behaviors. Pink1-/- rats demonstrated significantly delayed motility through the caecum and colon. Pink1-/- rats also had significantly lower fecal pellet count and higher fecal pellet weight after 24 h at 6 months of age. Results demonstrate that swallowing dysfunction occurs early in Pink1-/- rats. Delayed transit to the colon and constipation-like signs are also evident in this model. The presence of these early swallowing and GI deficits in Pink1-/- rats are analogous to those observed in human PD.

ALS-plus related clinical and genetic study from China

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder. An increasing number of researchers have found extra motor features in ALS, which are also called ALS-plus syndromes. Besides, a great majority of ALS patients also have cognitive impairment. However, clinical surveys of the frequency and genetic background of ALS-plus syndromes are rare, especially in China.

METHODS

We investigated a large cohort of 1015 patients with ALS, classifying them into six groups according to different extramotor symptoms and documenting their clinical manifestations. Meanwhile, based on their cognitive function, we divided these patients into two groups and compared demographic characteristics. Genetic screening for rare damage variants (RDVs) was also performed on 847 patients.

RESULTS

As a result, 16.75% of patients were identified with ALS-plus syndrome, and 49.5% of patients suffered cognitive impairment. ALS-plus group had lower ALSFRS-R scores, longer diagnostic delay time, and longer survival times, compared to ALS pure group. RDVs occurred less frequently in ALS-plus patients than in ALS-pure patients (P = 0.042) but showed no difference between ALS-cognitive impairment patients and ALS-cognitive normal patients. Besides, ALS-cognitive impairment group tends to harbour more ALS-plus symptoms than ALS-cognitive normal group (P = 0.001).

CONCLUSION

In summary, ALS-plus patients in China are not rare and show multiple differences from ALS-pure patients in clinical and genetic features. Besides, ALS-cognitive impairment group tends to harbour more ALS-plus syndrome than ALS-cognitive normal group. Our observations correspond with the theory that ALS involves several diseases with different mechanisms and provide clinical validation.

Striatal and thalamic automatic segmentation, morphology, and clinical correlates in Parkinsonism: Parkinson's disease, multiple system atrophy and progressive supranuclear palsy

Parkinson's disease (PD), multisystem atrophy (MSA), and progressive supranuclear palsy (PSP) present similarly with bradykinesia, tremor, rigidity, and cognitive impairments. Neuroimaging studies have found differential changes in the nigrostriatal pathway in these disorders, however whether the volume and shape of specific regions within this pathway can distinguish between atypical Parkinsonian disorders remains to be determined. This paper investigates striatal and thalamic volume and morphology as distinguishing biomarkers, and their relationship to neuropsychiatric symptoms. Automatic segmentation to calculate volume and shape analysis of the caudate nucleus, putamen, and thalamus were performed in 18 PD patients, 12 MSA, 15 PSP, and 20 healthy controls, then correlated with clinical measures. PSP bilateral thalami and right putamen were significantly smaller than controls, but not MSA or PD. The left caudate and putamen significantly correlated with the Neuropsychiatric Inventory total score. Bilateral thalamus, caudate, and left putamen had significantly different morphology between groups, driven by differences between PSP and healthy controls. This study demonstrated that PSP patient striatal and thalamic volume and shape are significantly different when compared with controls. Parkinsonian disorders could not be differentiated on volumetry or morphology, however there are trends for volumetric and morphological changes associated with PD, MSA, and PSP.

A genome-wide association study coupled with machine learning approaches to identify influential demographic and genomic factors underlying Parkinson's disease

Background: Despite the recent success of genome-wide association studies (GWAS) in identifying 90 independent risk loci for Parkinson's disease (PD), the genomic underpinning of PD is still largely unknown. At the same time, accurate and reliable predictive models utilizing genomic or demographic features are desired in the clinic for predicting the risk of Parkinson's disease. Methods: To identify influential demographic and genomic factors associated with PD and to further develop predictive models, we utilized demographic data, incorporating 200 variables across 33,473 participants, along with genomic data involving 447,089 SNPs across 8,840 samples, both derived from the Fox Insight online study. We first applied correlation and GWAS analyses to find the top demographic and genomic factors associated with PD, respectively. We further developed and compared a variety of machine learning (ML) models for predicting PD. From the developed ML models, we performed feature importance analysis to reveal the predictability of each demographic or the genomic input feature for PD. Finally, we performed gene set enrichment analysis on our GWAS results to identify PD-associated pathways. Results: In our study, we identified both novel and well-known demographic and genetic factors (along with the enriched pathways) related to PD. In addition, we developed predictive models that performed robustly, with AUC = 0.89 for demographic data and AUC = 0.74 for genomic data. Our GWAS analysis identified several novel and significant variants and gene loci, including three intron variants in LMNA (p-values smaller than 4.0e-21) and one missense variant in SEMA4A (p-value = 1.11e-26). Our feature importance analysis from the PD-predictive ML models highlighted some significant and novel variants from our GWAS analysis (e.g., the intron variant rs1749409 in the RIT1 gene) and helped identify potentially causative variants that were missed by GWAS, such as rs11264300, a missense variant in the gene DCST1, and rs11584630, an intron variant in the gene KCNN3. Conclusion: In summary, by combining a GWAS with advanced machine learning models, we identified both known and novel demographic and genomic factors as well as built well-performing ML models for predicting Parkinson's disease.

Soluble interleukin-1 receptor type 2 plasma levels in Parkinson's disease: relationship with cardiac autonomic profile before and after peripheral mechanical somatosensory stimulation

Introduction: Systemic inflammation promotes neurodegeneration in Parkinson's disease (PD). Interleukin-1 receptor type 2 (sIL-1R2) plasma levels increase during inflammation. Data on sIL-1R2 in PD patients and its relationship with PD cardiac autonomic profile are limited, given the possible anti-inflammatory effect of vagal activation. Previously, automated mechanical peripheral somatosensory stimulation (AMPSS) enhanced cardiac vagal modulation. Objectives were to 1) evaluate sIL-1R2 plasma concentrations in PD patients and healthy controls and 2) investigate the correlations between sIL-1R2 and cardiac autonomic indices obtained by spectrum analysis of heart rate variability before and after AMPSS. Methods: sIL-1R2 plasma levels were assessed in 48 PD patients and 50 healthy controls. Electrocardiogram and beat-by-beat arterial pressure were recorded at baseline and after 5 AMPSS sessions in 16 PD patients. Results: PD patients had higher sIL-1R2 levels than controls. In the PD subgroup, an inverse correlation between sIL-1R2 and HFnu was found. There was a negative correlation between changes induced by AMPSS on HFnu and sIL-1R2. Discussion: Higher sIL-1R2 levels in PD patients reflect the inflammatory dysregulation associated with the disease. In PD patients, higher sIL-1R2 was associated with reduced cardiovagal tone. Increased cardiovagal modulation following AMPSS was associated with lower sIL-1R2 levels in Parkinson's disease patients, suggesting inflammatory state improvement.

Validation of Administrative Health Data Algorithms for Identifying Persons with Parkinson's Disease and the 10-Year Prevalence Trend in Bologna, Italy

INTRODUCTION

Health administrative databases are widely used for the estimation of the prevalence of Parkinson's disease (PD). Few in general, and none used in Italy, have been validated by testing their diagnostic accuracy. The primary objective was to validate two algorithms for the identification of persons with PD using clinical diagnosis as the reference standard on an Italian sample of people with PD. The second objective was to estimate 10-year trends in PD prevalence in the Bologna Local Health Trust from 2010 to 2019.

METHODS

Two algorithms (index tests) applied to health administrative databases (hospital discharge, drug prescriptions, exemptions for medical costs) were validated against clinical diagnosis of PD by an expert neurologist (reference standard) in a cohort of consecutive outpatients. Sensitivity and specificity with relative 95% confidence intervals (CIs) were calculated. The prevalence of PD in a specific year was estimated as the ratio between the number of subjects fulfilling any criteria of the algorithm with better diagnostic accuracy and the total population in the same year (×1,000), stratified by age, sex, and district of residence.

RESULTS

The two algorithms showed high accuracy for identifying patients with PD: one with greater sensitivity of 94.2% (CI: 88.4-97.6) and the other with greater specificity of 98.1% (CI: 97.7-98.5). For the estimation of prevalence, we chose the most specific algorithm with the fewest total number of misclassified cases. We identified 3,798 people with PD as of December 31, 2019, corresponding to a prevalence of 4.3 per 1,000 inhabitants (CI: 4.2-4.4). Prevalence was higher in males (4.7, CI: 4.5-5.0) than females (3.8, CI: 3.7-4.0) and increased with age. The crude prevalence over time was slightly elevated as it followed a progressive aging of the population. When stratifying the prevalence for age groups, we did not observe a trend except in the 45-64 year category where we observed an increasing trend over time.

CONCLUSION

Algorithms based on administrative data are accurate when detecting people with PD in the Italian public health system. In a large northern Italian population, increased prevalence of about 10% was observed in the decade 2010-2019 and is explained by increased life expectancy. These data may be useful in planning the allocation of health care resources for people with PD.

The Enigmatic CA2: Exploring the Understudied Region of the Hippocampus and Its Involvement in Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disease that affects both motor and non-motor functions. Although motor impairment is a prominent clinical sign of PD, additional neurological symptoms may also occur, particularly in the preclinical and prodromal stages. Among these symptoms, social cognitive impairment is common and detrimental. This article aims to review non-motor symptoms in PD patients, focusing on social cognitive deficits. It also examines the specific characteristics of the CA2 region and its involvement in social behavior, highlighting recent advances and perspectives. Additionally, this review provides critical insights into and analysis of research conducted in rodents and humans, which may help improve the understanding of the current status of putative therapeutic strategies for social cognitive dysfunction in PD and potential avenues related to the function of the hippocampal CA2 region.

Parkinson's Disease: A Narrative Review on Potential Molecular Mechanisms of Sleep Disturbances, REM Behavior Disorder, and Melatonin

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. There is a wide range of sleep disturbances in patients with PD, such as insomnia and rapid eye movement (REM) sleep behavior disorder (or REM behavior disorder (RBD)). RBD is a sleep disorder in which a patient acts out his/her dreams and includes abnormal behaviors during the REM phase of sleep. On the other hand, melatonin is the principal hormone that is secreted by the pineal gland and significantly modulates the circadian clock and mood state. Furthermore, melatonin has a wide range of regulatory effects and is a safe treatment for sleep disturbances such as RBD in PD. However, the molecular mechanisms of melatonin involved in the treatment or control of RBD are unknown. In this study, we reviewed the pathophysiology of PD and sleep disturbances, including RBD. We also discussed the potential molecular mechanisms of melatonin involved in its therapeutic effect. It was concluded that disruption of crucial neurotransmitter systems that mediate sleep, including norepinephrine, serotonin, dopamine, and GABA, and important neurotransmitter systems that mediate the REM phase, including acetylcholine, serotonin, and norepinephrine, are significantly involved in the induction of sleep disturbances, including RBD in PD. It was also concluded that accumulation of α-synuclein in sleep-related brain regions can disrupt sleep processes and the circadian rhythm. We suggested that new treatment strategies for sleep disturbances in PD may focus on the modulation of α-synuclein aggregation or expression.

Salivary levels of disease-related biomarkers in the early stages of Parkinson's and Alzheimer's disease: A cross-sectional study

Introduction

Finding a non-invasive and repeatable tool has been recommended to make an accurate diagnosis of Alzheimer's disease (AD) and Parkinson's disease (PD).

Methods

70 volunteers participated in three groups: 24 with mild dementia of AD, 24 in the first and second stages of PD, and 22 healthy controls. After valuing the scores of cognitive tests, the salivary levels of phosphorylated tau (p-tau), total alpha-synuclein (α-syn), and beta-amyloid 1-42 (Aβ)‏‎ proteins have been evaluated. Finally, the cutoff points, receiver operating characteristic (ROC), sensitivity, and specificity have been calculated to find accurate and detectable biomarkers.

Results

Findings showed that the salivary level of Aβ was higher in both PD (p < 0.01) and AD (p < 0.001) patients than in controls. Moreover, the level of α-syn in both PD and AD patients was similarly lower than in controls (p < 0.05). However, the level of p-tau was only ‎higher in the AD group than in the control (p < 0.01). Salivary Aβ 1-42 level at a 60.3 pg/ml cutoff point revealed an excellent performance for diagnosing AD (AUC: 0.81).

Conclusion

Evaluation of p-tau, α-syn, and Aβ 1-42 levels in the saliva of AD and PD patients could help the early diagnosis. The p-tau level might be valuable for differentiation between AD and PD. Therefore, these hopeful investigations could be done to reduce the usage of invasive diagnostic methods, which alone is a success in alleviating the suffering of AD and PD patients. Moreover, introducing accurate salivary biomarkers according to the pathophysiology of AD and PD should be encouraged.

Beyond the Microbiota: Understanding the Role of the Enteric Nervous System in Parkinson's Disease from Mice to Human

The enteric nervous system (ENS) is a nerve network composed of neurons and glial cells that regulates the motor and secretory functions of the gastrointestinal (GI) tract. There is abundant evidence of mutual communication between the brain and the GI tract. Dysfunction of these connections appears to be involved in the pathophysiology of Parkinson's disease (PD). Alterations in the ENS have been shown to occur very early in PD, even before central nervous system (CNS) involvement. Post-mortem studies of PD patients have shown aggregation of α-synuclein (αS) in specific subtypes of neurons in the ENS. Subsequently, αS spreads retrogradely in the CNS through preganglionic vagal fibers to this nerve's dorsal motor nucleus (DMV) and other central nervous structures. Here, we highlight the role of the ENS in PD pathogenesis based on evidence observed in animal models and using a translational perspective. While acknowledging the putative role of the microbiome in the gut-brain axis (GBA), this review provides a comprehensive view of the ENS not only as a "second brain", but also as a window into the "first brain", a potentially crucial element in the search for new therapeutic approaches that can delay and even cure the disease.

The Spectrum of Neurological and Sensory Abnormalities in Gaucher Disease Patients: A Multidisciplinary Study (SENOPRO)

Gaucher disease (GD) has been increasingly recognized as a continuum of phenotypes with variable neurological and sensory involvement. No study has yet specifically explored the spectrum of neuropsychiatric and sensory abnormalities in GD patients through a multidisciplinary approach. Abnormalities involving the nervous system, including sensory abnormalities, cognitive disturbances, and psychiatric comorbidities, have been identified in GD1 and GD3 patients. In this prospective study, named SENOPRO, we performed neurological, neuroradiological, neuropsychological, ophthalmological, and hearing assessments in 22 GD patients: 19 GD1 and 3 GD3. First, we highlighted a high rate of parkinsonian motor and non-motor symptoms (including high rates of excessive daytime sleepiness), especially in GD1 patients harboring severe glucocerebrosidase variants. Secondly, neuropsychological evaluations revealed a high prevalence of cognitive impairment and psychiatric disturbances, both in patients initially classified as GD1 and GD3. Thirdly, hippocampal brain volume reduction was associated with impaired short- and long-term performance in an episodic memory test. Fourthly, audiometric assessment showed an impaired speech perception in noise in the majority of patients, indicative of an impaired central processing of hearing, associated with high rates of slight hearing loss both in GD1 and GD3 patients. Finally, relevant structural and functional abnormalities along the visual system were found both in GD1 and GD3 patients by means of visual evoked potentials and optical coherence tomography. Overall, our findings support the concept of GD as a spectrum of disease subtypes, and support the importance of in-depth periodic monitoring of cognitive and motor performances, mood, sleep patterns, and sensory abnormalities in all patients with GD, independently from the patient's initial classification.

Facial expression and emotion

Human facial expressions are unique in their ability to express our emotions and communicate them to others. The mimic expression of basic emotions is very similar across different cultures and has also many features in common with other mammals. This suggests a common genetic origin of the association between facial expressions and emotion. However, recent studies also show cultural influences and differences. The recognition of emotions from facial expressions, as well as the process of expressing one's emotions facially, occurs within an extremely complex cerebral network. Due to the complexity of the cerebral processing system, there are a variety of neurological and psychiatric disorders that can significantly disrupt the coupling of facial expressions and emotions. Wearing masks also limits our ability to convey and recognize emotions through facial expressions. Through facial expressions, however, not only "real" emotions can be expressed, but also acted ones. Thus, facial expressions open up the possibility of faking socially desired expressions and also of consciously faking emotions. However, these pretenses are mostly imperfect and can be accompanied by short-term facial movements that indicate the emotions that are actually present (microexpressions). These microexpressions are of very short duration and often barely perceptible by humans, but they are the ideal application area for computer-aided analysis. This automatic identification of microexpressions has not only received scientific attention in recent years, but its use is also being tested in security-related areas. This article summarizes the current state of knowledge of facial expressions and emotions.

Sexual Dysfunctions in Females with Parkinson's Disease: A Cross-Sectional Study with a Psycho-Endocrinological Perspective

Background and Objectives: Normal human sexual functioning is a complex integration of an intact neuroanatomic substrate, vascular supply, a balanced hormonal profile, and a predominance of excitatory over inhibitory psychological mechanisms. However, sexual functioning in Parkinson's disease (PD) is often overlooked in clinical practice, especially in female patients. Materials and Methods: In this cross-sectional study, we have investigated the frequency of sexual dysfunction and the possible correlation with psycho-endocrinological factors in a sample of women with idiopathic PD. Patients were assessed using a semi-structured sexual interview, in addition to psychometric tools, including the Hamilton Rating Scale for Anxiety and for Depression and the Coping Orientation to the Problems Experiences-New Italian Version. Specific blood tests, including testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen E2, prolactin (PRL), and vitamin D3 were also evaluated. Results: Our results reported a statistical difference in sexual intercourse frequency before and after the onset of PD (p < 0.001). The percentage of women who complained about reduced sexual desire increased after diagnosis (52.7%) compared to the period before the onset of the illness (36.8%). The endocrinological profile in females with PD revealed statistically significant differences regarding testosterone (p < 0.0006), estradiol (p < 0.00), vitamin D3 (p < 0.006), and calcium (0.002). Depression (44% characterized by perceived feelings of anger and frustration during sexual intercourse) and anxiety symptoms (29.5% reported feelings of fear and anxiety for not satisfying the partner) with abnormal coping strategies (48.14% experienced feelings of anger and intolerance) were also found to be statistically significant. This study showed a high frequency of sexual dysfunction in female patients with PD, which correlated with sexual hormone abnormalities, mood/anxiety, and coping strategies alterations. This supports the idea that there is a need to better investigate the sexual function of female patients with PD to provide them with an adequate therapeutic approach and potentially improve quality of life.

Phosphodiesterase-4 Inhibition in Parkinson's Disease: Molecular Insights and Therapeutic Potential

Clinicians and researchers are exploring safer and novel treatment strategies for treating the ever-prevalent Parkinson's disease (PD) across the globe. Several therapeutic strategies are used clinically for PD, including dopamine replacement therapy, DA agonists, MAO-B blockers, COMT blockers, and anticholinergics. Surgical interventions such as pallidotomy, particularly deep brain stimulation (DBS), are also employed. However, they only provide temporal and symptomatic relief. Cyclic adenosine monophosphate (cAMP) is one of the secondary messengers involved in dopaminergic neurotransmission. Phosphodiesterase (PDE) regulates cAMP and cGMP intracellular levels. PDE enzymes are subdivided into families and subtypes which are expressed throughout the human body. PDE4 isoenzyme- PDE4B subtype is overexpressed in the substantia nigra of the brain. Various studies have implicated multiple cAMP-mediated signaling cascades in PD, and PDE4 is a common link that can emerge as a neuroprotective and/or disease-modifying target. Furthermore, a mechanistic understanding of the PDE4 subtypes has provided perceptivity into the molecular mechanisms underlying the adverse effects of phosphodiesterase-4 inhibitors (PDE4Is). The repositioning and development of efficacious PDE4Is for PD have gained much attention. This review critically assesses the existing literature on PDE4 and its expression. Specifically, this review provides insights into the interrelated neurological cAMP-mediated signaling cascades involving PDE4s and the potential role of PDE4Is in PD. In addition, we discuss existing challenges and possible strategies for overcoming them.

Senolytics: opening avenues in drug discovery to find novel therapeutics for Parkinson's disease

Aging is one of the major risk factors for most neurodegenerative disorders including Parkinson's disease (PD). More than 10 million people are affected with PD worldwide. One of the predominant factors accountable for progression of PD pathology could be enhanced accumulation of senescent cells in the brain with the progress of age. Recent investigations have highlighted that senescent cells can ignite PD pathology via increased oxidative stress and neuroinflammation. Senolytics are agents that kill senescent cells. This review mainly focuses on understanding the pathological connection between senescence and PD, with emphasis on some of the recent advances made in the area of senolytics and their evolution to potential clinical candidates for future pharmaceuticals against PD.

Copy number analysis from whole-exome sequencing data revealed a novel homozygous deletion in PARK7 leads to severe early-onset Parkinson's disease

Parkinson's disease (PD), a neurodegenerative disease characterized by both motor neuron and non-motor neuron symptoms, is the most frequent neurodegenerative disease after Alzheimer's disease. Both genetic and environmental factors take part in disease etiology. Most cases are considered complex multifactorial diseases. About 15% of PD appear in the familial form, and about 5% of all cases arise from a single gene mutation. Among Mendelian causes of PD, PARK7 is one of the autosomal recessive forms due to loss-of-function mutations in both gene alleles. Both single nucleotide variants (SNVs) and copy number variations (CNVs) are observed in PARK7. This study presents an Iranian family with familial PD where some relatives had psychiatric disorders. A homozygous 1617 bp deletion in a female with early-onset PD was detected through copy-number analysis from whole-exome sequencing (WES) data in this consanguineous family. Further investigation by surveying microhomology revealed that the actual size of the deletion is 3,625 bp. This novel CNV that was in the PARK7gene is supposed to co-relation with early-onset PD and infertility in this family.

Neurological update: the palliative care landscape for atypical parkinsonian syndromes

Atypical parkinsonian syndromes are neurodegenerative conditions, characterised by rapid disease progression and shorter life expectancy compared to idiopathic Parkinson's disease. These conditions inflict substantial physical and psychosocial burden on patients and their families; hence, there is a clear rationale for a palliative care approach from diagnosis. An interdisciplinary care model has been shown to improve symptom burden, quality of life and engagement with advance care planning, in a heterogeneous group of neurodegenerative conditions. In this update, we summarise how the landscape for treating these patients has changed and the questions that still need to be resolved.

Pros and cons for statins use and risk of Parkinson's disease: An updated perspective

Parkinson's disease (PD) is the second most frequent neurodegenerative brain disease (NBD) after Alzheimer's disease (AD). Statins are the most common lipid-lowering agents used in the management of dyslipidemia and the prevention of primary and secondary cardiovascular diseases (CVD) events. In addition, there is a controversial point regarding the role of serum lipids in the pathogenesis of PD. In this bargain, as statins reduce serum cholesterol so they affect the PD neuropathology in bidirectional ways either protective or harmful. Statins are not used in the management of PD, but they are frequently used in the cardiovascular disorders commonly associated with PD in the elderly population. Therefore, the use of statins in that population may affect PD outcomes. Concerning the potential role of statins on PD neuropathology, there are conflicts and controversies either protective against the development of PD or harmful by increasing the risk for the development of PD. Therefore, this review aimed to clarify the precise role of statins in PD regarding the pros and cons from published studies. Many studies suggest a protective role of statins against PD risk through the modulation of inflammatory and lysosomal signaling pathways. Nevertheless, other observations suggest that statin therapy may increase PD risk by diverse mechanisms including reduction of CoQ10. In conclusion, there are strong controversies regarding the protective role of statins in PD neuropathology. Therefore, retrospective and prospective studies are necessary in this regard.

Proximity to residential and workplace pesticides application and the risk of progression of Parkinson's diseases in Central California

BACKGROUND

Pesticide exposure has consistently been associated with Parkinson's disease (PD) onset. Yet, fewer epidemiologic studies have examined whether pesticides influence PD motor and non-motor symptom progression.

OBJECTIVES

Using a geographic information system tool that integrates agricultural pesticide use reports and land use records to derive ambient exposures at residences and workplaces, we assessed associations between specific pesticides previously related to PD onset with PD symptom progression in two PD patient cohorts living in agricultural regions of California.

METHODS

We calculated the pounds of pesticide applied agriculturally near each participant's residential or occupational addresses from 1974 to the year of PD diagnosis, using a geographic information system tool that links the California Pesticide Use Reports database to land use data. We examined 53 pesticides selected a priori as they have previously been associated with PD onset. We longitudinally followed two PD patient cohorts (PEG1 N = 242, PEG2 N = 259) for an average of 5.0 years (SD ± 3.5) and 2.7 years (SD ± 1.6) respectively and assessed PD symptoms using the movement disorder specialist-administered Unified Parkinson's disease Rating Scale part III (UPDRS), Mini-Mental State Examination (MMSE), and Geriatric Depression Scale (GDS). Weighted time-to-event regression models were implemented to estimate effects.

RESULTS

Ten agricultural pesticides, including copper sulfate (pentahydrate), 2-methyl-4-chlorophenoxyacetic acid (MCPA) dimethylamine salt, tribufos, sodium cacodylate, methamidophos, ethephon, propargite, bromoxynil octanoate, monosodium methanearsonate (MSMA), and dicamba, were associated with faster symptom progression. Among these pesticides, residential or workplace proximity to higher amounts of copper sulfate (pentahydrate) and MCPA (dimethylamine salt) was associated with all three progression endpoints (copper sulfate: HRs = 1.22-1.36, 95 % CIs = 1.03-1.73; MCPA: HRs = 1.27-1.35, 95 % CIs = 1.02-1.70).

CONCLUSIONS

Our findings suggest that pesticide exposure may not only be relevant for PD onset but also PD progression phenotypes. We have implicated ten specific pesticide active ingredients in faster PD motor and non-motor decline.

Electroconvulsive Seizure Normalizes Motor Deficits and Induces Autophagy Signaling in the MPTP-Induced Parkinson Disease Mouse Model

OBJECTIVE

Electroconvulsive seizure (ECS) is a potent treatment modality for various neuropsychiatric diseases, including Parkinson disease (PD). Recent animal studies showed that repeated ECS activates autophagy signaling, the impairment of which is known to be involved in PD. However, the effectiveness of ECS on PD and its therapeutic mechanisms have not yet been investigated in detail.

METHODS

Systemic injection of a neurotoxin 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP), which destroys dopaminergic neurons in the substantia nigra compacta (SNc), in mice was utilized to induce an animal model of PD. Mice were treated with ECS 3 times per week for 2 weeks. Behavioral changes were measured with a rotarod test. Molecular changes related to autophagy signaling in midbrain including SNc, striatum, and prefrontal cortex were analyzed with immunohistochemistry and immunoblot analyses.

RESULTS

Repeated ECS treatments normalized the motor deficits and the loss of dopamiergic neurons in SNc of the MPTP PD mouse model. In the mouse model, LC3-II, an autophagy marker, was increased in midbrain while decreased in prefrontal cortex, both of which were reversed by repeated ECS treatments. In the prefrontal cortex, ECS-induced LC3-II increase was accompanied with AMP-activated protein kinase (AMPK)-Unc-51-like kinase 1-Beclin1 pathway activation and inhibition of mamalian target of rapamycin signaling which promotes autophagy initiation.

CONCLUSION

The findings revealed the therapeutic effects of repeated ECS treatments on PD, which could be attributed to the neuroprotective effect of ECS mediated by AMPK-autophagy signaling.

The lived experience of stigma and parkinson's disease in Kenya: a public health challenge

BACKGROUND

As a disease characterised by non-motor and very visible motor symptoms, Parkinson's disease has been associated with multiple forms of stigma, while awareness about the disease globally remains low. The experience of stigma relating to Parkinson's disease from high-income nations is well-documented, while less is known about low- and middle-income countries (LMICs). Literature on stigma and disease from Africa and the Global South has described the added complexities people face resulting from structural violence, as well as perceptions about symptoms and disease associated with supernatural beliefs, which can have significant implications for access to healthcare and support. Stigma is a recognised barrier to health-seeking behaviour and a social determinant of population health.

METHODS

This study draws on qualitative data collected as part of a wider ethnographic study to explore the lived experience of Parkinson's disease in Kenya. Participants include 55 people diagnosed with Parkinson's and 23 caregivers. The paper draws on the Health Stigma and Discrimination Framework as a tool to understand stigma as a process.

RESULTS

Data from interviews identified the drivers and facilitators of stigma, including poor awareness of Parkinson's, lack of clinical capacity, supernatural beliefs, stereotypes, fear of contagion and blame. Participants reported their lived realities of stigma, and experiences of stigma practices, which had significant negative health and social outcomes, including social isolation and difficulty accessing treatment. Ultimately, stigma had a negative and corrosive effect on the health and wellbeing of patients.

CONCLUSION

This paper highlights the interplay of structural constraints and the negative consequences of stigma experienced by people living with Parkinson's in Kenya. The deep understanding of stigma made possible through this ethnographic research leads us to see stigma as a process, something that is embodied and enacted. Targeted and nuanced ways of tackling stigma are suggested, including educational and awareness campaigns, training, and the development of support groups. Importantly, the paper shows that awareness of, and advocacy for the recognition of, Parkinson's globally needs to improve. This recommendation is in line with the World Health Organization's Technical Brief on Parkinson disease, which responds to the growing public health challenge posed by Parkinson's.

Multidomain cognitive training increases physical activity in people with Parkinson's disease with mild cognitive impairment

INTRODUCTION

Cognitive impairment in Parkinson's disease (PD), especially in patients with mild cognitive impairment (PD-MCI), coincides with less physical activity. Cognitive trainings (CT) have been found to promote laboratory environment-based movement. Knowledge about their effect in natural home-based environment, reflecting everyday function, is sparse. This explorative study investigated short-term effects of CT on physical activity assessed by home-based accelerometry, and its relation to change of cognitive function over time and non-cognitive outcomes in patients with PD-MCI. Cognitive and non-cognitive correlates of movement parameters at pretest were evaluated as well.

METHODS

Eighteen patients with PD-MCI of the TrainParC study were analyzed. Those patients received either a 6-week multidomain group CT or physical training (PT). Physical activity and sedentary behavior were assessed with wearable accelerometers worn up to seven days pre- and post-training.

RESULTS

Patients in the CT group displayed significantly greater increases in active periods after training than patients assigned to PT. In the CT group, increases in executive functioning were associated with increases in active periods and decreases in active mean bout length after training. At pretest, reduced working memory correlated with longer sedentary mean bout length, and impairment in activities of daily living (ADL) correlated with a higher number of sedentary periods.

CONCLUSION

Study data revealed that CT can increase physical activity in patients with PD-MCI, possibly due to effects on executive functions, which needs further investigation in larger sample sizes. Lower working memory performance and ADL impairment might be associated with a more inactive lifestyle in patients with PD-MCI.