Non-motor symptoms in Parkinson's disease

The Increase of Theta Power and Decrease of Alpha/Theta Ratio as a Manifestation of Cognitive Impairment in Parkinson's Disease

In this study, we aim to assess and examine cognitive functions in Parkinson's Disease patients using EEG recordings, with a central focus on characteristics associated with a cognitive decline. Based on neuropsychological evaluation using Mini-Mental State Examination, Montreal Cognitive Assessment, and Addenbrooke's Cognitive Examination-III, 98 participants were divided into three cognitive groups. All the particpants of the study underwent EEG recordings with spectral analysis. The results revealed an increase in the absolute theta power in patients with Parkinson's disease dementia (PD-D) compared to cognitively normal status (PD-CogN, p=0.00997) and a decrease in global relative beta power in PD-D compared to PD-CogN (p=0.0413). An increase in theta relative power in the left temporal region (p=0.0262), left occipital region (p=0.0109), and right occipital region (p=0.0221) were observed in PD-D compared to PD-N. The global alpha/theta ratio and global power spectral ratio significantly decreased in PD-D compared to PD-N (p = 0.001). In conclusion, the increase in relative theta power and the decrease in relative beta power are characteristic changes in EEG recordings in PD patients with cognitive impairment. Identifying these changes can be a useful biomarker and a complementary tool in the neuropsychological diagnosis of cognitive impairment in Parkinson's Disease.

Targeting α-synuclein post-translational modifications in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease characterized by the progressive loss of dopaminergic neurons in the nigrostriatal pathway. Although the exact mechanisms underlying PD are still not completely understood, it is well accepted that α-synuclein plays key pathophysiological roles as the main constituent of the cytoplasmic inclusions known as Lewy bodies. Several post-translational modifications (PTMs), such as the best-known phosphorylation, target α-synuclein and are thus implicated in its physiological and pathological functions. In this review, we present (1) an overview of the pathophysiological roles of α-synuclein, (2) a descriptive analysis of α-synuclein PTMs, including phosphorylation, ubiquitination, SUMOylation, acetylation, glycation, truncation, and O-GlcNAcylation, as well as (3) a brief summary on α-synuclein PTMs as potential biomarkers for PD. A better understanding of α-synuclein PTMs is of paramount importance for elucidating the mechanisms underlying PD and can thus be expected to improve early detection and monitoring disease progression, as well as identify promising new therapeutic targets.

Premotor, nonmotor and motor symptoms of Parkinson's Disease: A new clinical state of the art

Parkinson's Disease (PD) is a neurodegenerative disorder that affects dopaminergic neurons in the mesencephalic substantia nigra, causing a progressive clinical course characterized by pre-motor, non-motor and motor symptoms, which negatively impact the quality of life of patients and cause high health care costs. Therefore, the present study aims to discuss the clinical manifestations of PD and to make a correlation with the gut-brain (GB) axis, approaching epidemiology and therapeutic perspectives, to better understand its clinical progression and identify symptoms early. A literature review was performed regarding the association between clinical progression, the gut-brain axis, epidemiology, and therapeutic perspectives, in addition to detailing pre-motor, non-motor symptoms (neuropsychiatric, cognitive, autonomic, sleep disorders, sensory abnormalities) and cardinal motor symptoms. Therefore, this article addresses a topic of extreme relevance, since the previously mentioned clinical manifestations (pre-motor and non-motor) can often act as prodromal markers for the early diagnosis of PD and may precede it by up to 20 years.

Both Motor and Non-Motor Fluctuations Matter in the Clinical Management of Patients with Parkinson's Disease: An Exploratory Study

Non-motor symptoms (NMS) characterize the Parkinson's disease (PD) clinical picture, and as well as motor fluctuations, PD patients can also experience NMS fluctuations (NMF). The aim of this observational study was to investigate the presence of NMS and NMF in patients with PD using the recently validated Non-Motor Fluctuation Assessment questionnaire (NoMoFa) and to evaluate their associations with disease characteristics and motor impairment. Patients with PD were consecutively recruited, and NMS, NMF, motor impairment, motor fluctuations, levodopa-equivalent daily dose, and motor performance were evaluated. One-third of the 25 patients included in the study (10 females, 15 males, mean age: 69.9 ± 10.3) showed NMF, and patients with NMF presented a higher number of NMS (p < 0.01). Static NMS and NoMoFa total score were positively associated with motor performance assessed with the Global Mobility Task (p < 0.01 and p < 0.001), and the latter was also correlated with motor impairment (p < 0.05) but not with motor fluctuations. Overall, this study shows evidence that NMF are frequently reported by mild-to-moderate PD patients and associated with an increased number of NMS. The relationship between NoMoFa total score and motor functioning highlights the importance of understanding the clinical role of NMS and NMF in the management of PD patients.

Non-visual hallucinations in Parkinson's disease: a systematic review

BACKGROUND

Non-visual hallucinations in Parkinson's disease (PD) can be prevalent and distressing. Most existing research has however, focused on visual hallucinations as well as related risk factors. The current study thus conducted a systematic review to collate existing evidence on non-visual hallucinations in PD, focusing on their prevalence, phenomenology, and clinical-cognitive correlates.

METHODS

Ninety-one relevant studies were included from a systematic search across PsycINFO APA, PubMed, and Web of Science, for peer-reviewed publications in the English language, from 1970 to the present. These comprised a mix of case (30 studies; n = 56) and group design (62 studies; n = 7346) studies, divided into three somewhat overlapping collections to address our three research foci.

RESULTS

Prevalence estimates for hallucinations were: auditory 1.5-72.0%, olfactory 1.6-21.0%, somatic-tactile 0.4-22.5%, gustatory 1.0-15.0%, and sensed presence 0.9-73.3%. Phenomenological inquiries revealed descriptions of vivid, consuming events replete with elaborate detail, adversely affecting PD patients in different ways. Overt experiences of multisensory hallucinations were also highly variable (0.4-80%) but exceedingly common, reported by almost half of the 45 included prevalence studies. There was some evidence for modality-specific hallucination predictors, but this was largely tentative, pending robust replication.

CONCLUSIONS

Marked prevalence figures coupled with phenomenological descriptions implicating distress denote that non-visual and multisensory hallucinations in PD are of clinical significance. More direct research and clinical attention need to be devoted to the study and management of such hallucinatory experiences.

Early approaches of YKL-40 as a biomarker and therapeutic target for Parkinson's disease

Aim: To investigate whether the estimation of cerebrospinal fluid (CSF) and brain YKL-40 levels may be used as an efficient biomarker for Parkinson's disease (PD). Methods: Lipopolysaccharides (LPS) was injected into the right substantia nigra pars compacta (SNpc). Rats were divided into: control group, early LPS-induced PD group (14 days), and advanced LPS-induced PD group (28 days). YKL-40 and other related factors were detected in CSF and brain tissue. Results: Increased expression of YKL-40 was observed in brain tissue and CSF of PD-induced rats associated with triggered inflammatory cytokine release. Conclusion: The current study was limited to detecting YKL-40 and other inflammatory factors in brain and CSF. YKL-40 may be considered as an early biomarker and therapeutic target for PD.

Depression After Parkinson's Disease: Treated Differently or Not At All?

Depression is a common, potentially debilitating non-motor symptom of Parkinson's disease which may manifest at any time and can respond to treatment. Although depression is a known primary mediator of health-related quality of life, it is currently unknown whether the timing of depression diagnosis relative to PD diagnosis affects receipt of depression treatment. Electronic health record data were examined to explore differences in depression treatment among patients diagnosed with depression before or after PD diagnosis. Compared to PD patients diagnosed with depression prior to PD, those diagnosed with depression following PD are less likely to receive any treatment, either pharmacologic or non-pharmacologic, indicating a temporal association between the time of PD diagnosis and receipt of depression treatment. This highlights a potentially substantial treatment gap, despite the existence of efficacious treatment. Diagnosis with PD appears to alter depression treatment and further research is warranted to determine potential causes and effective interventions.

Parkinson's Disease Stigma Questionnaire (PDStigmaQuest): Development and Pilot Study of a Questionnaire for Stigma in Patients with Idiopathic Parkinson's Disease

BACKGROUND

Stigma is significant in Parkinson's disease (PD). However, no specific tool is available to assess stigma in PD comprehensively.

OBJECTIVE

This pilot study aimed to develop and test a stigma questionnaire specific to PD patients (PDStigmaQuest).

METHODS

Based on a literature review, clinical experience, expert consensus, and patients' feedback, we developed the preliminary, patient-completed PDStigmaQuest in German language. It included 28 items covering five stigma domains: uncomfortableness, anticipated stigma, hiding, experienced stigma, and internalized stigma. In this pilot study, 81 participants (PD patients, healthy controls, caregivers, and health professionals) were included to investigate the acceptability, feasibility, comprehensibility, and psychometric properties of the PDStigmaQuest.

RESULTS

The PDStigmaQuest showed 0.3% missing data points for PD patients and 0.4% for controls, suggesting high data quality. Moderate floor effects, but no ceiling effects were found. In the item analysis, most items met the standard criteria of item difficulty, item variance, and item-total correlation. Cronbach's alpha was > 0.7 for four of five domains. PD patients' domain scores were significantly higher than healthy controls' for uncomfortableness, anticipated stigma, and internalized stigma. Feedback to the questionnaire was predominantly positive.

CONCLUSION

Our results indicate that the PDStigmaQuest is a feasible, comprehensive, and relevant tool to assess stigma in PD and helps to understand the construct of stigma in PD further. Based on our results, the preliminary version of the PDStigmaQuest was modified and is currently validated in a larger population of PD patients for use in clinical and research settings.

Parkinsonian phenotypes induced by Synphilin-1 expression are differentially contributed by serotonergic and dopaminergic circuits and suppressed by nicotine treatment

Synphilin-1 is a protein encoded by the human SNCAIP gene whose function has yet to be fully understood. However, it has been linked to familial Parkinson's disease (PD). Synphilin-1 is a major component of the Lewy bodies found in neurons in the substantia nigra pars compacta of PD patients. Synphilin-1 expression in serotonergic and/or dopaminergic neurons of Drosophila melanogaster induces neurodegeneration, as well as motor and non-motor PD like symptoms. In this work, we examined the contribution of the serotonergic and dopaminergic circuits in the development of PD-like phenotypes. We found that olfactory and visual symptoms are majorly contributed by the serotonergic system, and that motor symptoms and reduction in survival are mainly contributed by the dopaminergic system. Chronic nicotine treatment was able to suppress several of these symptoms. These results indicate that both the serotonergic and dopaminergic systems contribute to different aspects of PD symptomatology and that nicotine has beneficial effects on specific symptoms.

Genetically engineered mesenchymal stem cells with dopamine synthesis for Parkinson's disease in animal models

Although striatal delivery of three critical genes for dopamine synthesis by viruses is a potential clinical approach for treating Parkinson's disease (PD), the approach makes it difficult to finely control dopamine secretion amounts and brings safety concerns. Here, we generate genetically engineered mesenchymal stem cells encoding three critical genes for dopamine synthesis (DOPA-MSCs). DOPA-MSCs retain their MSC identity and stable ability to secrete dopamine during passaging. Following transplantation, DOPA-MSCs reinstate striatal dopamine levels and correct motor function in PD rats. Importantly, after grafting into the caudate and putamen, DOPA-MSCs provide homotopic reconstruction of midbrain dopamine pathways by restoring striatal dopamine levels, and safely and long-term (up to 51 months) correct motor disorders and nonmotor deficits in acute and chronic PD rhesus monkey models of PD even with advanced PD symptoms. The long-term benefits and safety results support the idea that the development of dopamine-synthesized engineered cell transplantation is an important strategy for treating PD.

Oral ENT-01 Targets Enteric Neurons to Treat Constipation in Parkinson Disease : A Randomized Controlled Trial

BACKGROUND

Parkinson disease (PD) is associated with α-synuclein (αS) aggregation within enteric neurons. ENT-01 inhibits the formation of αS aggregates and improved constipation in an open-label study in patients with PD.

OBJECTIVE

To evaluate the safety and efficacy of oral ENT-01 for constipation and neurologic symptoms in patients with PD and constipation.

DESIGN

Randomized, placebo-controlled phase 2b study. (ClinicalTrials.gov: NCT03781791).

SETTING

Outpatient.

PATIENTS

150 patients with PD and constipation.

INTERVENTION

ENT-01 or placebo daily for up to 25 days. After baseline assessment of constipation severity, daily dosing was escalated to the prokinetic dose, the maximum dose (250 mg), or the tolerability limit, followed by a washout period.

MEASUREMENTS

The primary efficacy end point was the number of complete spontaneous bowel movements (CSBMs) per week. Neurologic end points included dementia (assessed using the Mini-Mental State Examination [MMSE]) and psychosis (assessed using the Scale for the Assessment of Positive Symptoms adapted for PD [SAPS-PD]).

RESULTS

The weekly CSBM rate increased from 0.7 to 3.2 in the ENT-01 group versus 0.7 to 1.2 in the placebo group (P < 0.001). Improvement in secondary end points included SBMs (P = 0.002), stool consistency (P < 0.001), ease of passage (P = 0.006), and laxative use (P = 0.041). In patients with dementia, MMSE scores improved by 3.4 points 6 weeks after treatment in the ENT-01 group (n = 14) versus 2.0 points in the placebo group (n = 14). Among patients with psychosis, SAPS-PD scores improved from 6.5 to 1.7 six weeks after treatment in the ENT-01 group (n = 5) and from 6.3 to 4.4 in the placebo group (n = 6). ENT-01 was well tolerated, with no deaths or drug-related serious adverse events. Adverse events were predominantly gastrointestinal, including nausea (34.4% [ENT-01] vs. 5.3% [placebo]; P < 0.001) and diarrhea (19.4% [ENT-01] vs. 5.3% [placebo]; P = 0.016).

LIMITATION

Longer treatment periods need to be investigated in future studies.

CONCLUSION

ENT-01 was safe and significantly improved constipation.

PRIMARY FUNDING SOURCE

Enterin, Inc.

Scale-Free Functional Brain Networks Exhibit Increased Connectivity, Are More Integrated and Less Segregated in Patients with Parkinson's Disease following Dopaminergic Treatment

Dopaminergic treatment (DT), the standard therapy for Parkinson's disease (PD), alters the dynamics of functional brain networks at specific time scales. Here, we explore the scale-free functional connectivity (FC) in the PD population and how it is affected by DT. We analyzed the electroencephalogram of: (i) 15 PD patients during DT (ON) and after DT washout (OFF) and (ii) 16 healthy control individuals (HC). We estimated FC using bivariate focus-based multifractal analysis, which evaluated the long-term memory ( H ( 2 ) ) and multifractal strength ( Δ H 15 ) of the connections. Subsequent analysis yielded network metrics (node degree, clustering coefficient and path length) based on FC estimated by H ( 2 ) or Δ H 15 . Cognitive performance was assessed by the Mini Mental State Examination (MMSE) and the North American Adult Reading Test (NAART). The node degrees of the Δ H 15 networks were significantly higher in ON, compared to OFF and HC, while clustering coefficient and path length significantly decreased. No alterations were observed in the H ( 2 ) networks. Significant positive correlations were also found between the metrics of H ( 2 ) networks and NAART scores in the HC group. These results demonstrate that DT alters the multifractal coupled dynamics in the brain, warranting the investigation of scale-free FC in clinical and pharmacological studies.

Cognitive Digital Intervention for Older Patients with Parkinson's Disease during COVID-19: A Mixed-Method Pilot Study

Mild cognitive impairment is frequent among people with Parkinson's disease. Cognitive training seems effective for cognitive status and for mitigating anxiety and depression. With the COVID-19 outbreak, such therapeutic interventions were delivered online. This longitudinal mixed-method study was aimed at evaluating the effectiveness of an online cognitive treatment, carried out during COVID times and based on Parkinson's-Adapted Cognitive Stimulation Therapy, on cognitive domains and mood of 18 older people with Parkinson's disease. After screening, the cognitive status and mood were assessed three times by Addenbrooke's Cognitive Examination-Revised scale and the Geriatric Depression Scale-Short Form. At the follow-up, patients were also interviewed for understanding their experience with the technology. Such treatment was effective on the participants' cognitive functions, but not on their mood. Despite some initial problems with the technology, the online intervention was experienced as a way of not being 'left behind', staying in contact with others, and being safe during the lockdown. This suggests that online cognitive treatment can be adopted to integrate face-to-face interventions by increasing their efficacy, accessibility, and long-term outcomes. Suggestions for future research are given.

Common and unique dysconnectivity profiles of dorsal and median raphe in Parkinson's disease

The serotonergic (5-HT) system, which undergoes degeneration in Parkinson's disease (PD), is involved in the pathogenesis of motor and nonmotor symptoms. The dorsal raphe (DR) and median raphe (MR) nuclei are the main source of 5-HT neurons, however, brain connectivity changes in these two nuclei have not been delineated in PD. Here we used resting-state fMRI (rs-fMRI) to characterize functional connectivity profiles of DR and MR and further examine the associations between dysconnectivity of raphe nuclei and clinical phenotypes of PD. We found that DR and MR commonly hypo-connected with the sensorimotor, temporal, and occipital cortex, limbic system, left thalamus, putamen, and cerebellum in PD. DR had unique decreased connectivity with the bilateral prefrontal and cingulate cortices, while MR had lower connectivity with the pons. Moreover, reduced connectivity of DR correlated with depression, drowsiness, and anxiety, whereas dysconnectivity of MR correlated with depression, cognitive deficits, sleep disturbances, and pain. Our findings highlight the complex roles of raphe nuclei in motor and nonmotor symptoms, providing novel insights into the neurophysiological mechanisms underlying pathogenesis of PD.

Vexed mutations promote degeneration of dopaminergic neurons through excessive activation of the innate immune response

The hallmark of Parkinson's disease (PD) is the loss of dopaminergic (DA) neurons in the brain. However, little is known about why DA neurons are selectively vulnerable to PD. We previously completed a screen identifying genes associated with the progressive degeneration of DA neurons. Here we describe the role of a previously uncharacterized gene, CG42339, in the loss of DA neurons using Drosophila Melanogaster. CG42339 mutants display a progressive loss of DA neurons and locomotor dysfunction, along with an accumulation of advanced glycation end products (AGEs) in the brain. Based on this phenotype, we refer to CG42339 as vexed. We demonstrate that vexed is specifically required within cortex glia to maintain neuronal viability. Loss of vexed function results in excessive activation of the innate immune response in the brain, leading to loss of DA neurons. We show that activation of the innate immune response leads to increased nitric oxide signaling and accumulation of AGEs, which ultimately result in neurodegeneration. These results provide further insight into the relationship between the role of the immune response in the central nervous system and how this impacts neuronal viability.

The Impact of the COVID-19 Pandemic on Informal Caregivers of People With Parkinson's Disease Residing in the UK: A Qualitative Study

Informal caregivers can experience various demands when providing care and support for People with Parkinson's disease (PwP) in their own homes. The outbreak of SARS-CoV-2 and public health strategies employed to mitigate the spread of COVID-19 have presented challenges to the general populace on a global basis. The present study used a qualitative research design to explore how the COVID-19 pandemic has impacted informal caregivers in their role of providing care for PwP in their own homes. A series of 1:1 semi-structured interviews were conducted with 11 informal caregivers of PwP (M age = 72.64 years, SD = 8.94 years). A thematic analysis indicated that 1) vulnerabilities to COVID-19, 2) home maintenance & activities of daily living and 3) engagement with healthcare services were 3 themes that provided indications on how the COVID-19 pandemic impacted informal caregivers of PwP. The present study provides illustrations of how being an informal caregiver of PwP and being identified as high risk to COVID-19 can present challenges to the process of caring for loved ones who are also vulnerable to SARS-CoV-2. The results of the present study highlights the necessity to develop strategies to ensure that informal caregivers have the necessary resources to provide care for PwP in their homes and also maintain their own well-being in the post COVID-19 era.

pTDP-43 aggregates accumulate in non-central nervous system tissues prior to symptom onset in amyotrophic lateral sclerosis: a case series linking archival surgical biopsies with clinical phenotypic data

Neurodegenerative diseases such as Parkinson's disease (PD), Alzheimer's disease (AD), and amyotrophic lateral sclerosis (ALS) are traditionally considered strictly neurological disorders. However, clinical presentation is not restricted to neurological systems, and non-central nervous system (CNS) manifestations, particularly gastrointestinal (GI) symptoms, are common. Our objective was to understand the systemic distribution of pathology in archived non-CNS tissues, taken as part of routine clinical practice during life from people with ALS. We examined tissue from 13 people who went on to develop ALS; including sporadic ALS (n = 12) and C9orf72 hexanucleotide repeat expansion (n = 1). The tissue cohort consisted of 68 formalin-fixed paraffin embedded samples from 21 surgical cases (some patients having more than one case over their lifetimes), from 8 organ systems, which we examined for evidence of phosphorylated TDP-43 (pTDP-43) pathology. We identified pTDP-43 aggregates in multiple cell types of the GI tract, including macrophages and dendritic cells within the lamina propria; as well as ganglion/neuronal and glial cells of the myenteric plexus. Aggregates were also noted within lymph node parenchyma, blood vessel endothelial cells, and chondrocytes. We note that in all cases with non-CNS pTDP-43 pathology, aggregates were present prior to ALS diagnosis and in some instances preceded neurological symptom onset by more than 10 years. These data imply that patients with microscopically unexplained non-CNS symptoms could have occult protein aggregation that could be detected many years prior to neurological involvement.

Propagation of Parkinson's disease by extracellular vesicle production and secretion

Parkinson's disease (PD) is a common neurodegenerative condition affecting a significant number of individuals globally, resulting in the presentation of debilitating motor and non-motor symptoms, including bradykinesia, resting tremor, as well as mood and sleep disorders. The pathology of PD has been observed to spread through the central nervous system resulting in progressive brain degeneration and a poor prognosis. Aggregated forms of the protein α-synuclein, particularly intermediary aggregates, referred to as oligomers, or preformed fibrils, have been implicated as the causative agent in the degeneration of neuronal processes, including the dysfunction of axonal transport, mitochondrial activity, and ultimately cellular death. Extracellular vesicles (EVs) have been strongly implicated in the propagation of PD pathology. Current observations suggest that aggregated α-synuclein is transported between neurons via small EVs in a series of exocytosis and endocytosis cellular processes leading to the observed spread of neurotoxicity and cellular death. Despite some understanding of the role of EVs in neurodegeneration, the exact mechanism by which these lipidic particles participate in the progression of Parkinson's pathology is not entirely understood. Here we review the current understanding of the role of EVs in the propagation of PD and explore their potential as a therapeutic target.

Calabria as a Genetic Isolate: A Model for the Study of Neurodegenerative Diseases

Although originally multi-ethnic in its structure, nowadays the Calabria region of southern Italy represents an area with low genetic heterogeneity and a high level of consanguinity that allows rare mutations to be maintained due to the founder effect. A complex research methodology—ranging from clinical activity to the genealogical reconstruction of families/populations across the centuries, the creation of databases, and molecular/genetic research—was modelled on the characteristics of the Calabrian population for more than three decades. This methodology allowed the identification of several novel genetic mutations or variants associated with neurodegenerative diseases. In addition, a higher prevalence of several hereditary neurodegenerative diseases has been reported in this population, such as Alzheimer’s disease, frontotemporal dementia, Parkinson’s disease, Niemann–Pick type C disease, spinocerebellar ataxia, Creutzfeldt–Jakob disease, and Gerstmann–Straussler–Scheinker disease. Here, we summarize and discuss the results of research data supporting the view that Calabria could be considered as a genetic isolate and could represent a model, a sort of outdoor laboratory—similar to very few places in the world—useful for the advancement of knowledge on neurodegenerative diseases.

Predictors of prodromal Parkinson's disease in young adult Pink1-/- rats

Parkinson's disease (PD) is a progressive, degenerative disease that affects nearly 10 million people worldwide. Hallmark limb motor signs and dopamine depletion have been well studied; however, few studies evaluating early stage, prodromal biology exist. Pink1-/- rats, a rodent model of PD mitochondrial dysfunction, exhibit early stage behavioral deficits, including vocal communication and anxiety, that progress during mid-to-late adulthood (6-12 months of age). Yet, the biological pathways and mechanisms that lead to prodromal dysfunction are not well understood. This study investigated the Pink1-/- rat in young adulthood (2 months of age). Mixed sex groups of Pink1-/- rats and wildtype (WT) controls were assayed for limb motor, anxiety, and vocal motor behaviors. A customized NanoString CodeSet, based on genetic work in later adulthood, was used to probe for the up regulation of genes involved in disease pathways and inflammation within the brainstem and vocal fold muscle. In summary, the data show sex- and genotype-differences in limb motor, anxiety, and vocal motor behaviors. Specifically, female Pink1-/- rats demonstrate less anxiety-like behavior compared to male Pink1-/- rats and female rats show increased locomotor activity compared to male rats. Pink1-/- rats also demonstrate prodromal ultrasonic vocalization dysfunction across all acoustic parameters and sex differences were present for intensity (loudness) and peak frequency. These data demonstrate a difference in phenotype in the Pink1-/- model. Tuba1c transcript level was identified as a key marker negatively correlated to ultrasonic vocalization at 2 months of age. Identifying genes, such as Tuba1c, may help determine early predictors of PD pathology in the Pink1-/- rat and serve as targets for future drug therapy studies.

Harnessing the Therapeutic Potential of the Nrf2/Bach1 Signaling Pathway in Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative movement disorder characterized by a progressive loss of dopaminergic neurons in the substantia nigra pars compacta. Although a complex interplay of multiple environmental and genetic factors has been implicated, the etiology of neuronal death in PD remains unresolved. Various mechanisms of neuronal degeneration in PD have been proposed, including oxidative stress, mitochondrial dysfunction, neuroinflammation, α-synuclein proteostasis, disruption of calcium homeostasis, and other cell death pathways. While many drugs individually targeting these pathways have shown promise in preclinical PD models, this promise has not yet translated into neuroprotective therapies in human PD. This has consequently spurred efforts to identify alternative targets with multipronged therapeutic approaches. A promising therapeutic target that could modulate multiple etiological pathways involves drug-induced activation of a coordinated genetic program regulated by the transcription factor, nuclear factor E2-related factor 2 (Nrf2). Nrf2 regulates the transcription of over 250 genes, creating a multifaceted network that integrates cellular activities by expressing cytoprotective genes, promoting the resolution of inflammation, restoring redox and protein homeostasis, stimulating energy metabolism, and facilitating repair. However, FDA-approved electrophilic Nrf2 activators cause irreversible alkylation of cysteine residues in various cellular proteins resulting in side effects. We propose that the transcriptional repressor of BTB and CNC homology 1 (Bach1), which antagonizes Nrf2, could serve as a promising complementary target for the activation of both Nrf2-dependent and Nrf2-independent neuroprotective pathways. This review presents the current knowledge on the Nrf2/Bach1 signaling pathway, its role in various cellular processes, and the benefits of simultaneously inhibiting Bach1 and stabilizing Nrf2 using non-electrophilic small molecules as a novel therapeutic approach for PD.

Screening for non-motor symptoms in Egyptian patients with Parkinson’s disease

Background

Most of the patients with Parkinson’s disease (PD) suffer from non-motor symptoms (NMS). Despite their marked effect on patients’ quality of life, NMS remain under-estimated by physicians, patients and caregivers. The aim of this study was to suggest a battery to screen for the presence of NMS in PD patients in the setting of an outpatient clinic and to assess the NMS of PD in Egyptian patients and factors affecting them.

Results

This study was conducted on 50 patients with PD, 35 males (70%) and 15 females (30%) whom their age ranged from 36 to 80 years with a mean of 62.88 ± 8.74 years. All patients were assessed using the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), Apathy Scale (AS), Montreal Cognitive Assessment (MOCA), Hamilton Depression Rating Scale (HDRS) and Parkinson’s Disease Sleep Scale (PDSS). The mean age at disease onset was 59.10 ± 9.34 years and the mean disease duration was 3.76 ± 3.16 years. 98% of patients (49 out of 50) had at least one non-motor symptom. The mean MDS-UPDRS scores were 15.74 ± 7.93 for part I, 17.94 ± 11.61 for part II and 42.32 ± 22.74 for part III. The mean score for AS was 9.90 ± 10.66 with 70% of patients considered apathetic. The mean MOCA score was 21.12 ± 4.73 with 38 patients (76%) found to be cognitively impaired. The mean HDRS score was 12.26 ± 8.52 with 34 patients (68%) found to be depressed. The mean PDSS score was 92.22 ± 32.53 with sleep disturbances found in 38 patients (76%). A statistically significant negative correlation was found between the HDRS and PDSS scores (P value < 0.001). Age of patients, age at disease onset and disease duration were not correlated to MDS-UPDRS, AS, MOCA, HDRS and PDSS scores.

Conclusions

Most of the patients with PD were found to suffer from NMS including apathy, cognitive impairment, depression and sleep disturbances. Physicians need to screen their PD patients for NMS on regular basis using the appropriate tools. Self-administered questionnaires could function as reliable screening tools for NMS in PD patients.

Prediction of Cognitive Degeneration in Parkinson's Disease Patients Using a Machine Learning Method

This study developed a predictive model for cognitive degeneration in patients with Parkinson's disease (PD) using a machine learning method. The clinical data, plasma biomarkers, and neuropsychological test results of patients with PD were collected and utilized as model predictors. Machine learning methods comprising support vector machines (SVMs) and principal component analysis (PCA) were applied to obtain a cognitive classification model. Using 32 comprehensive predictive parameters, the PCA-SVM classifier reached 92.3% accuracy and 0.929 area under the receiver operating characteristic curve (AUC). Furthermore, the accuracy could be increased to 100% and the AUC to 1.0 in a PCA-SVM model using only 13 carefully chosen features.

Prevalence and incidence of non‐motor symptoms in individuals with and without Parkinson's disease

Background

The prevalence ratio (PR) and incidence rate ratio (IRR) of nonmotor symptoms (NMS) were calculated for early Parkinson's disease (PD) versus non‐PD from 2 observational studies.

Methods

NMS were assessed through the self‐reported Non‐Motor Symptom Questionnaire in the online Fox Insight study and through self‐ and clinician‐rated scales in the Parkinson's Progression Marker Initiative (PPMI) study. Age‐ and sex‐adjusted/matched PR and IRR were estimated for each NMS by PD status using Poisson regression.

Results

Most NMS occurred more frequently in PD. Among 15,194 Fox Insight participants, sexual dysfunction had the largest adjusted PR (12.4 [95% CI, 6.9–22.2]) and dysgeusia/hyposmia had the largest adjusted IRR over a 2‐year median follow‐up (17.0 [95% CI, 7.8–37.1]). Among 607 PPMI participants, anosmia had the largest PR (16.6 [95% CI, 6.1–44.8]). During the 7‐year median follow‐up, hallucinations had the largest IRR (13.5 [95% CI, 6.3–28.8]).

Conclusion

Although many NMS are more common in early PD than in non‐PD, their occurrence may differ with time (hallucinations) or data collection methods (sexual dysfunction).

Sleep Dysfunction in Movement Disorders: a Window to the Disease Biology

PURPOSE OF REVIEW

To comprehensively summarize the sleep pathologies associated with movement disorders, focusing on neurodegenerative diseases.

RECENT FINDINGS

Mounting evidence has further implicated both sleep and circadian disruption in the pathophysiology of many movement disorders. In particular, recent data illuminate the mechanisms by which poor sleep quality and circadian dysfunction can exacerbate neurodegeneration. In addition, anti-IgLON5 disease is a recently described autoimmune disease with various symptoms that can feature prominent sleep disruption and parasomnia. Many movement disorders are associated with sleep and circadian rhythm disruption. Motor symptoms can cause sleep fragmentation, resulting in insomnia and excessive daytime sleepiness. Many neurodegenerative movement disorders involve brainstem pathology in regions close to or affecting nuclei that regulate sleep and wake. Further, commonly used movement medications may exacerbate sleep concerns. Providers should screen for and address these sleep symptoms to improve function and quality of life for patients and caregivers.

Targeting thalamic circuits rescues motor and mood deficits in PD mice

Although bradykinesia, tremor and rigidity are the hallmark motor defects in patients with Parkinson's disease (PD), patients also experience motor learning impairments and non-motor symptoms such as depression¹. The neural circuit basis for these different symptoms of PD are not well understood. Although current treatments are effective for locomotion deficits in PD^2,3, therapeutic strategies targeting motor learning deficits and non-motor symptoms are lacking^4-6. Here we found that distinct parafascicular (PF) thalamic subpopulations project to caudate putamen (CPu), subthalamic nucleus (STN) and nucleus accumbens (NAc). Whereas PF→CPu and PF→STN circuits are critical for locomotion and motor learning, respectively, inhibition of the PF→NAc circuit induced a depression-like state. Whereas chemogenetically manipulating CPu-projecting PF neurons led to a long-term restoration of locomotion, optogenetic long-term potentiation (LTP) at PF→STN synapses restored motor learning behaviour in an acute mouse model of PD. Furthermore, activation of NAc-projecting PF neurons rescued depression-like phenotypes. Further, we identified nicotinic acetylcholine receptors capable of modulating PF circuits to rescue different PD phenotypes. Thus, targeting PF thalamic circuits may be an effective strategy for treating motor and non-motor deficits in PD.

Modeling Parkinson's disease-related symptoms in alpha-synuclein overexpressing mice

BACKGROUND

Intracellular deposition of alpha-synuclein (α-syn) as Lewy bodies and Lewy neurites is a central event in the pathogenesis of Parkinson's disease (PD) and other α-synucleinopathies. Transgenic mouse models overexpressing human α-syn, are useful research tools in preclinical studies of pathogenetic mechanisms. Such mice develop α-syn inclusions as well as neurodegeneration with a topographical distribution that varies depending on the choice of promoter and which form of α-syn that is overexpressed. Moreover, they display motor symptoms and cognitive disturbances that to some extent resemble the human conditions.

PURPOSE

One of the main motives for assessing behavior in these mouse models is to evaluate the potential of new treatment strategies, including their impact on motor and cognitive symptoms. However, due to a high within-group variability with respect to such features, the behavioral studies need to be applied with caution. In this review, we discuss how to make appropriate choices in the experimental design and which tests that are most suitable for the evaluation of PD-related symptoms in such studies.

METHODS

We have evaluated published results on two selected transgenic mouse models overexpressing wild type (L61) and mutated (A30P) α-syn in the context of their validity and utility for different types of behavioral studies.

CONCLUSIONS

By applying appropriate behavioral tests, α-syn transgenic mouse models provide an appropriate experimental platform for studies of symptoms related to PD and other α-synucleinopathies.

TNF-α promotes α-synuclein propagation through stimulation of senescence-associated lysosomal exocytosis

Cell-to-cell propagation of α-synuclein is thought to be the underlying mechanism of Parkinson's disease progression. Recent evidence suggests that inflammation plays an important role in the propagation of protein aggregates. However, the mechanism by which inflammation regulates the propagation of aggregates remains unknown. Here, using in vitro cultures, we found that soluble factors secreted from activated microglia promote cell-to-cell propagation of α-synuclein and further showed that among these soluble factors, TNF-α had the most robust stimulatory activity. Treatment of neurons with TNF-α triggered cellular senescence, as shown by transcriptomic analyses demonstrating induction of senescence-associated genes and immunoanalysis of senescence phenotype marker proteins. Interestingly, secretion of α-synuclein was increased in senescent neurons, reflecting acquisition of a senescence-associated secretory phenotype (SASP). Using vacuolin-1, an inhibitor of lysosomal exocytosis, and RNAi against rab27a, we demonstrated that the SASP was mediated by lysosomal exocytosis. Correlative light and electron microscopy and immunoelectron microscopy confirmed that propagating α-synuclein aggregates were present in electron-dense lysosome-like compartments. TNF-α promoted the SASP through stimulation of lysosomal exocytosis, thereby increasing the secretion of α-synuclein. Collectively, these results suggest that TNF-α is the major inflammatory factor that drives cell-to-cell propagation of α-synuclein by promoting the SASP and subsequent secretion of α-synuclein.

Mechanistic insights into accelerated α-synuclein aggregation mediated by human microbiome-associated functional amyloids

The gut microbiome has been shown to have key implications in the pathogenesis of Parkinson's disease (PD). The Escherichia coli functional amyloid CsgA is known to accelerate α-synuclein aggregation in vitro and induce PD symptoms in mice. However, the mechanism governing CsgA-mediated acceleration of α-synuclein aggregation is unclear. Here, we show that CsgA can form stable homodimeric species that correlate with faster α-synuclein amyloid aggregation. Furthermore, we identify and characterize new CsgA homologs encoded by bacteria present in the human microbiome. These CsgA homologs display diverse aggregation kinetics, and they differ in their ability to modulate α-synuclein aggregation. Remarkably, we demonstrate that slowing down CsgA aggregation leads to an increased acceleration of α-synuclein aggregation, suggesting that the intrinsic amyloidogenicity of gut bacterial CsgA homologs affects their ability to accelerate α-synuclein aggregation. Finally, we identify a complex between CsgA and α-synuclein that functions as a platform to accelerate α-synuclein aggregation. Taken together, our work reveals complex interplay between bacterial amyloids and α-synuclein that better informs our understanding of PD causation.

Personality Changes After Subthalamic Nucleus Stimulation in Parkinson’s Disease

Background:

While deep brain stimulation of the subthalamic nucleus (STN-DBS) significantly improves motor deficits in patients with Parkinson’s disease (PD), it is still unclear whether it affects personality functioning.

Objective:

The objective of the present study was to examine personality changes in patients with PD after STN-DBS from the perspectives of both the patients and caregivers. Moreover, by assessing the premorbid personalities of the patients, we tried to determine individual vulnerability to STN-DBS-induced personality changes.

Methods:

In total, 27 patients and their caregivers participated in our retrospective observational study. They were asked to assess the patients’ personality changes with the Iowa Scale of Personality Changes (ISPC) and the patients’ premorbid personalities with the Big Five Inventory (BFI).

Results:

Caregivers reported significant personality changes in the ISPC domains of Executive Disturbance (p = 0.01) and Disturbed Social Behavior (p = 0.02). Most of the ISPC domains were positively correlated with Conscientiousness, while Executive Disturbance was negatively correlated with Neuroticism of the BFI scale.

Conclusion:

Our results show that executive and social functioning are the two most vulnerable domains in patients with PD after STN-DBS, especially in those patients who score higher for neuroticism and lower for conscientiousness on the BFI scale. The results of our study may provide movement disorder specialists with better counseling options and better selection of DBS candidates. Caregivers’ perspective might contribute significantly in understanding postoperative personality changes.

Exploring the multifactorial aspects of Gut Microbiome in Parkinson's Disease

Advanced research in health science has broadened our view in approaching and understanding the pathophysiology of diseases and has also revolutionised diagnosis and treatment. Ever since the establishment of Braak’s hypothesis in the propagation of alpha-synuclein from the distant olfactory and enteric nervous system towards the brain in Parkinson’s Disease (PD), studies have explored and revealed the involvement of altered gut microbiota in PD. This review recapitulates the gut microbiome associated with PD severity, duration, motor and non-motor symptoms, and antiparkinsonian treatment from recent literature. Gut microbial signatures in PD are potential predictors of the disease and are speculated to be used in early diagnosis and treatment. In brief, the review also emphasises on implications of the prebiotic, probiotic, faecal microbiota transplantation, and dietary interventions as alternative treatments in modulating the disease symptoms in PD.

Characterization of retinal function and structure in the MPTP murine model of Parkinson’s disease

In addition to well characterized motor symptoms, visual disturbances are increasingly recognized as an early manifestation in Parkinson’s disease (PD). A better understanding of the mechanisms underlying these changes would facilitate the development of vision tests which can be used as preclinical biomarkers to support the development of novel therapeutics for PD. This study aims to characterize the retinal phenotype of a mouse model of dopaminergic dysfunction and to examine whether these changes are reversible with levodopa treatment. We use a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD to characterize the neurotoxic effects of MPTP on in vivo retinal function (electroretinography, ERG), retinal structure (optical coherence tomography, OCT) and retinal dopaminergic cell number (tyrosine hydroxylase immunohistochemistry, IHC) at two time points (21 and 45 days) post MPTP model induction. We also investigate the effect of levodopa (L-DOPA) as a proof-of-principle chronic intervention against MPTP-induced changes in the retina. We show that MPTP decreases dopaminergic amacrine cell number (9%, p < 0.05) and that a component of the ERG that involves these cells, in particular oscillatory potential (OP) peak timing, was significantly delayed at Day 45 (7–13%, p < 0.01). This functional deficit was paralleled by outer plexiform layer (OPL) thinning (p < 0.05). L-DOPA treatment ameliorated oscillatory potential deficits (7–13%, p < 0.001) in MPTP animals. Our data suggest that the MPTP toxin slows the timing of inner retinal feedback circuits related to retinal dopaminergic pathways which mirrors findings from humans with PD. It also indicates that the MPTP model causes structural thinning of the outer retinal layer on OCT imaging that is not ameliorated with L-DOPA treatment. Together, these non-invasive measures serve as effective biomarkers for PD diagnosis as well as for quantifying the effect of therapy.

Diagnostic classification of Parkinson’s disease based on non-motor manifestations and machine learning strategies

Non-motor manifestations of Parkinson’s disease (PD) appear early and have a significant impact on the quality of life of patients, but few studies have evaluated their predictive potential with machine learning algorithms. We evaluated 9 algorithms for discriminating PD patients from controls using a wide collection of non-motor clinical PD features from two databases: Biocruces (96 subjects) and PPMI (687 subjects). In addition, we evaluated whether the combination of both databases could improve the individual results. For each database 2 versions with different granularity were created and a feature selection process was performed. We observed that most of the algorithms were able to detect PD patients with high accuracy (>80%). Support Vector Machine and Multi-Layer Perceptron obtained the best performance, with an accuracy of 86.3% and 84.7%, respectively. Likewise, feature selection led to a significant reduction in the number of variables and to better performance. Besides, the enrichment of Biocruces database with data from PPMI moderately benefited the performance of the classification algorithms, especially the recall and to a lesser extent the accuracy, while the precision worsened slightly. The use of interpretable rules obtained by the RIPPER algorithm showed that simply using two variables (autonomic manifestations and olfactory dysfunction), it was possible to achieve an accuracy of 84.4%. Our study demonstrates that the analysis of non-motor parameters of PD through machine learning techniques can detect PD patients with high accuracy and recall, and allows us to select the most discriminative non-motor variables to create potential tools for PD screening.

Occupational Therapy Practice Guidelines for People With Parkinson's Disease

IMPORTANCE

Occupational therapy practitioners address the occupational performance and participation needs of people with Parkinson's disease (PD) and their care partners.

OBJECTIVE

This Practice Guideline is informed by systematic reviews on the use of occupational therapy interventions to promote participation in occupations for people with PD and to facilitate their caregivers' participation in the caregiver role. This guideline is meant to support practitioners' clinical decision making when working with people with PD and their care partners.

METHOD

We examined and synthesized the results of four systematic reviews and integrated those results into clinical recommendations for practice.

RESULTS

Thirty-three articles from the systematic reviews served as the basis for the clinical recommendations in this Practice Guideline. Clinical recommendations are provided for interventions that have strong or moderate supporting evidence.

CONCLUSION AND RECOMMENDATIONS

Multidisciplinary, tailored, goal-oriented intervention is recommended for people with PD. Various forms of exercise can be used to improve activities of daily living and instrumental activities of daily living performance and social participation, and interventions should incorporate health behavior change techniques to support adequate physical activity levels in daily life. Mindfulness meditation and exercise can be used to support sleep, and task-oriented training can be used to improve performance of specific tasks. Occupational therapy practitioners should incorporate self-management, coaching, compensatory, cognitive-behavioral, and other approaches into multicomponent treatment plans depending on the client's needs and goals. Additional potentially appropriate intervention approaches or areas to address are discussed on the basis of existing or emerging evidence and expert opinion. What This Article Adds: This Practice Guideline provides a summary and applications of the current evidence supporting occupational therapy intervention for people with PD. It includes case examples and suggested decision-making algorithms to support practitioners in addressing client goals.

Sustained chemogenetic activation of locus coeruleus norepinephrine neurons promotes dopaminergic neuron survival in synucleinopathy

Dopaminergic neuron degeneration in the midbrain plays a pivotal role in motor symptoms associated with Parkinson's disease. However, non-motor symptoms of Parkinson's disease and post-mortem histopathology confirm dysfunction in other brain areas, including the locus coeruleus and its associated neurotransmitter norepinephrine. Here, we investigate the role of central norepinephrine-producing neurons in Parkinson's disease by chronically stimulating catecholaminergic neurons in the locus coeruleus using chemogenetic manipulation. We show that norepinephrine neurons send complex axonal projections to the dopaminergic neurons in the substantia nigra, confirming physical communication between these regions. Furthermore, we demonstrate that increased activity of norepinephrine neurons is protective against dopaminergic neuronal depletion in human α-syn A53T missense mutation over-expressing mice and prevents motor dysfunction in these mice. Remarkably, elevated norepinephrine neurons action fails to alleviate α-synuclein aggregation and microgliosis in the substantia nigra suggesting the presence of an alternate neuroprotective mechanism. The beneficial effects of high norepinephrine neuron activity might be attributed to the action of norepinephrine on dopaminergic neurons, as recombinant norepinephrine treatment increased primary dopaminergic neuron cultures survival and neurite sprouting. Collectively, our results suggest a neuroprotective mechanism where noradrenergic neurons activity preserves the integrity of dopaminergic neurons, which prevents synucleinopathy-dependent loss of these cells.

Inhibition of colony stimulating factor-1 receptor (CSF-1R) as a potential therapeutic strategy for neurodegenerative diseases: opportunities and challenges

Microglia are specialized dynamic immune cells in the central nervous system (CNS) that plays a crucial role in brain homeostasis and in disease states. Persistent neuroinflammation is considered a hallmark of many neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson's disease (PD), Huntington’s disease (HD), amyotrophic lateral sclerosis (ALS) and primary progressive multiple sclerosis (MS). Colony stimulating factor 1-receptor (CSF-1R) is predominantly expressed on microglia and its expression is significantly increased in neurodegenerative diseases. Cumulative findings have indicated that CSF-1R inhibitors can have beneficial effects in preclinical neurodegenerative disease models. Research using CSF-1R inhibitors has now been extended into non-human primates and humans. This review article summarizes the most recent advances using CSF-1R inhibitors in different neurodegenerative conditions including AD, PD, HD, ALS and MS. Potential challenges for translating these findings into clinical practice are presented.

pTDP-43 aggregates accumulate in the gut and other non-central nervous system tissues prior to symptom onset in amyotrophic lateral sclerosis.. [DOI: 10.1101/2022.03.17.484805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Objective

Neurodegenerative diseases such as Parkinson’s disease (PD), Alzheimer’s disease (AD) and amyotrophic lateral sclerosis (ALS) are traditionally considered strictly neurological disorders. However, clinical presentation is not restricted to neurological systems, and non-central nervous system (CNS) manifestations, particularly gastrointestinal (GI) symptoms, are common. Our objective was to understand the systemic distribution of pathology in archived non-CNS tissues, taken as part of routine clinical practice during life from people with ALS.

Design

We requested all surgical specimens of non-CNS tissue taken during life from 48 people with ALS, for whom evidence of the characteristic proteinopathy associated with ALS had been identified in the CNS after death (i.e., the pathological cytoplasmic accumulation of phosphorylated TDP-43 (pTDP-43) aggregates). Of the 48 patients, 13 had sufficient tissue for evaluation: 12 patients with sporadic ALS and 1 patient with aC9orf72hexanucleotide repeat expansion. The final cohort consisted of 68 formalin-fixed paraffin embedded tissue samples from 22 surgical cases (some patients having more than one case over their lifetimes), representing 8 organ systems, which we examined for evidence of pTDP-43 pathology. The median age of tissue removal was 62.4 years old and median tissue removal to death was 6.3 years.

Results

We identified pTDP-43 aggregates in multiple cell types of the GI tract (i.e., colon and gallbladder), including macrophages and dendritic cells within the lamina propria, as well as neuronal and glial cells of the myenteric plexus. Aggregates were also noted within lymph node parenchyma, blood vessel endothelial cells, and chondrocytes. We note that in all cases with non-CNS pTDP-43 pathology, aggregates were present prior to ALS diagnosis (median=3years) and, in some instances, preceded neurological symptom onset by more than 10 years.

Conclusion

These data imply that patients with non-CNS symptoms may have occult protein aggregation that could be detected many years prior to neurological involvement.

Summary

Neurodegenerative diseases such as Parkinson’s disease (PD), Alzheimer’s disease (AD) and amyotrophic lateral sclerosis (ALS) are traditionally considered strictly neurological disorders. However, clinical presentation is not restricted to neurological systems, and non-central nervous system (CNS) manifestations, particularly gastrointestinal (GI) symptoms, are common. Our objective was to understand the systemic distribution of TDP-43 pathology in archived non-CNS tissues, taken as part of routine clinical practice during life from people with ALS. We identified pTDP-43 aggregates in multiple cell types of the GI tract (i.e., colon and gallbladder), and within lymph node parenchyma, blood vessel endothelial cells, and chondrocytes. We note that in all cases with non-CNS pTDP-43 pathology, aggregates were present prior to ALS diagnosis (median=24months) and, in some instances, preceded neurological symptom onset by more than 10years. These data imply that patients with non-CNS symptoms may have occult protein aggregation tha could be detected many years prior to neurological involvement.

Graphical Abstract

Graphical Abstract.

Ante-mortem tissue cohort comprised of tissue taken from people with ALS demonstrates non-CNS accumulation of pTDP-43 aggregates prior to symptom onset.

Schematic of workflow to identify pTDP-43 aggregates indicative of non-central nervous system (CNS) manifestations of ALS. Lower panel left: cartoon depicting organs and cell types that had evidence of pTDP-43 aggregation in ALS patient non-CNS ante-mortem tissue. Lower panel right: cartoon depicting organs with no evidence of pTDP-43 aggregation in ALS patient non-CNS ante-mortem tissue.

Relation of serum level of tumor necrosis factor-alpha to cognitive functions in patients with Parkinson’s disease

Background

Inflammation is suggested to play a role in the development of non-motor Parkinson’s disease (PD) symptoms. We aimed to investigate the association between serum tumor necrosis factor-alpha (TNF-α) levels and cognition in PD patients. Thirty patients with PD and 30 healthy controls were included. Evaluation and staging of PD were done using Unified PD Rating Scale. Cognitive assessment was done using Addenbrooke’s Cognitive Examination (ACE-III) and trail making B tests. Measurement of serum levels of TNF-α was done.

Results

Patients had significantly worser cognitive scores than controls except for language subclass of ACE score. Mean serum TNF-α level was significantly greater in PD patients as compared to controls. TNF-α serum level was significantly negatively correlated with ACE visuospatial function. Sensitivity and specificity of TNF-α to detect cognitive dysfunction in PD using ACE III and trail making B tests were (73.1, 75%), (57.1, 56.2%), respectively, whereas sensitivity and specificity of TNF-α to detect severity of PD using H&Y staging in PD were 50%.

Conclusion

Patients with PD frequently have cognitive impairment. Elevated serum TNF-α levels in patients with PD, and association of this cytokine to visuospatial impairment, implicate this pro-inflammatory cytokine in the neurobiology of cognitive impairment in PD.

Recent Update on the Development of Leucine- Rich Repeat Kinase 2 (LRRK2) Inhibitors: A Promising Target for the Treatment of Parkinson's Disease

Parkinson's disease is a relatively common neurological disorder with incidence increasing with age. Since current medications only relieve the symptoms and do not change the course of the disease, therefore, finding disease-modifying therapies is a critical unmet medical need. However, significant progress in understanding how genetics underpins Parkinson's disease (PD) has opened up new opportunities for understanding disease pathogenesis and identifying possible therapeutic targets. One such target is leucine-rich repeat kinase 2 (LRRK2), an elusive enzyme implicated in both familial and idiopathic PD risk. As a result, both academia and industry have promoted the development of potent and selective inhibitors of LRRK2. In this review, we have summarized recent progress on the discovery and development of LRKK2 inhibitors as well as the bioactivity of several small-molecule LRRK2 inhibitors that have been used to inhibit LRRK2 kinase activity in vitro or in vivo.

Mapping Motor Pathways in Parkinson’s Disease Patients with Subthalamic Deep Brain Stimulator: A Diffusion MRI Tractography Study

Introduction

This study assessed the safety of postoperative diffusion tensor imaging (DTI) with on-state deep brain stimulation (DBS) and the feasibility of reconstruction of the white matter tracts in the vicinity of the stimulation site of the subthalamic nucleus (STN). The association between the impact of DBS on the nigrostriatal pathway (NSP) and the treatment effect on motor symptoms in Parkinson’s disease (PD) was then evaluated.

Methods

Thirty-one PD patients implanted with STN-DBS (mean age: 66 years; 25 male) were scanned on a 1.5-T magnetic resonance imaging (MRI) scanner using the DTI sequence with DBS on. Twenty-three of them were scanned a second time with DBS off. The NSP, dentato-rubro-thalamic tract (DRTT), and hyperdirect pathway (HDP) were generated using both deterministic and probabilistic tractography methods. The DBS-on-state and off-state tractography results were validated and compared. Afterward, the relationships between the characteristics of the reconstructed white matter tracts and the clinical assessment of PD symptoms and the DBS effect were further examined.

Results

No adverse events related to DTI were identified in either the DBS-on-state or off-state. Overall, the NSP was best reconstructed, followed by the DRTT and HDP, using the probabilistic tractography method. The connection probability of the left NSP was significantly lower than that of the right side (p < 0.05), and a negative correlation (r = −0.39, p = 0.042) was identified between the preoperative symptom severity in the medication-on state and the connection probability of the left NSP in the DBS-on-state images. Furthermore, the distance from the estimated left-side volume of tissue activated (VTA) by STN-DBS to the ipsilateral NSP was significantly shorter in the DBS-responsive group compared to the DBS-non-responsive group (p = 0.046).

Conclusions

DTI scanning is safe and delineation of white matter pathway is feasible for PD patients implanted with the DBS device. Postoperative DTI is a useful technique to strengthen our current understanding of the therapeutic effect of DBS for PD and has the potential to refine target selection strategies for brain stimulation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-022-00331-1.

For some more seriously affected Parkinson’s disease (PD) patients, drugs are no longer effective in treating their symptoms. An alternate treatment is to use deep brain stimulation (DBS), a commonly used neurosurgical therapy for PD patients. For those DBS treatments targeting the subthalamic nucleus (STN), the electrical stimulation used may impact nearby white matter tracts and alter the effectiveness of the DBS treatment. The nigrostriatal pathway (NSP), dentato-rubro-thalamic tract, and hyperdirect pathway are three white matter tracts near the STN. They are all relevant to motor symptoms in PD. This study examined whether imaging these tracts using magnetic resonance imaging (MRI) is safe and feasible in the presence of DBS leads. The relationships between the fiber-tracking characteristics and distance to the DBS leads were then evaluated. For this purpose, 31 PD patients with stimulation-on were scanned on a 1.5 T MRI scanner using a diffusion tensor imaging sequence. A total of 23 subjects underwent another scan using the same sequence with stimulation-off. No adverse events related to diffusion tensor imaging were found. Among the white matter tracts near the STN, the NSP was best delineated, followed by the dentato-rubro-thalamic tract and the hyperdirect pathway. The connection probability of the left NSP was significantly lower than that of the right side as were the subject’s motor symptoms. The closer the distance between the NSP and the stimulation location, the better the DBS outcome. These findings indicate that imaging white matter tracts with DBS on is safe and useful in mapping DBS outcomes.

Demoralization and Quality of Life of Patients with Parkinson Disease

INTRODUCTION

Demoralization is quite prevalent in patients with Parkinson disease (PD). Unrecognized or untreated, demoralization may progress, at times, to demands for euthanasia and the desire for suicide. Typically, patients with PD do not complain of being "demoralized"; rather, they report disruptions in the quality of their lives. Hence, early identification of disruptions in health-related quality of life (HRQoL) specifically associated with demoralization may prompt earlier recognition and treatment. Published data on such associations, however, could not be found. Alleviation of demoralization in PD is likely to improve treatment outcomes.

OBJECTIVE

This research aimed at identifying the disruptions of HRQoL specifically associated with the demoralization of patients with PD.

METHODS

Consecutive general hospital outpatients with PD (n = 95) were assessed for: demoralization, with the Diagnostic Criteria for Psychosomatic Research Demoralization Scale (DCPR-D) and the Demoralization Scale (DS); depression, with the Patient Health Questionnaire-9 (PHQ-9); HRQoL, with the Parkinson Disease Questionnaire-Short Form (PDQ-8); sociodemographic variables; medical comorbidities; PD severity; and types of treatment.

RESULTS

The prevalence of demoralization was 19%. Regression analyses showed that demoralization was significantly more likely to be experienced by participants who had difficulty with mobility and felt embarrassed in public due to having PD. Demoralization explained HRQoL over and above depression.

CONCLUSIONS

Stigma and perceived difficulty with mobility are associated with demoralization of PD patients, and they may signal the need for psychotherapeutic and behavioral interventions to prevent the progression to helplessness, hopelessness, demands for euthanasia, and desire for suicide.

Peripheral neuropathy in Parkinson's disease: prevalence and functional impact on gait and balance

Peripheral neuropathy is a common problem in patients with Parkinson's disease. Peripheral neuropathy's prevalence in Parkinson's disease varies between 4.8-55%, compared with 9% in the general population. It remains unclear whether peripheral neuropathy leads to decreased motor performance in Parkinson's disease, resulting in impaired mobility and increased balance deficits. We aimed to determine the prevalence and type of peripheral neuropathy in Parkinson's disease patients and evaluate its functional impact on gait and balance. A cohort of consecutive Parkinson's disease patients assessed by movement disorders specialists based on the UK Brain Bank criteria underwent clinical, neurophysiological (nerve conduction studies and quantitative sensory testing) and neuropathological (intraepidermal nerve fibre density in skin biopsy punches) evaluation to characterize the peripheral neuropathy type and aetiology using a cross-sectional design. Gait and balance were characterized using wearable health-technology in OFF and ON medication states, and the main parameters were extracted using validated algorithms. A total of 99 Parkinson's disease participants with a mean age of 67.2 (±10) years and mean disease duration of 6.5 (±5) years were assessed. Based on a comprehensive clinical, neurophysiological and neuropathological evaluation, we found that 40.4% of Parkinson's disease patients presented peripheral neuropathy, with a predominance of small fibre neuropathy (70% of the group). In the OFF state, the presence of peripheral neuropathy was significantly associated with shorter stride length (P = 0.029), slower gait speed (P = 0.005) and smaller toe-off angles (P = 0.002) during straight walking; significantly slower speed (P = 0.019) and smaller toe-off angles (P = 0.007) were also observed during circular walking. In the ON state, the above effects remained, albeit moderately reduced. With regard to balance, significant differences between Parkinson's disease patients with and without peripheral neuropathy were observed in the OFF medication state during stance with closed eyes on a foam surface. In the ON states, these differences were no longer observable. We showed that peripheral neuropathy is common in Parkinson's disease and influences gait and balance parameters, as measured with mobile health-technology. Our study supports that peripheral neuropathy recognition and directed treatment should be pursued in order to improve gait in Parkinson's disease patients and minimize balance-related disability, targeting individualized medical care.

Fat and Protein Combat Triggers Immunological Weapons of Innate and Adaptive Immune Systems to Launch Neuroinflammation in Parkinson's Disease

Parkinson's disease (PD) is the second-most common neurodegenerative disease in the world, affecting up to 10 million people. This disease mainly happens due to the loss of dopaminergic neurons accountable for memory and motor function. Partial glucocerebrosidase enzyme deficiency and the resultant excess accumulation of glycosphingolipids and alpha-synuclein (α-syn) aggregation have been linked to predominant risk factors that lead to neurodegeneration and memory and motor defects in PD, with known and unknown causes. An increasing body of evidence uncovers the role of several other lipids and their association with α-syn aggregation, which activates the innate and adaptive immune system and sparks brain inflammation in PD. Here, we review the emerging role of a number of lipids, i.e., triglyceride (TG), diglycerides (DG), glycerophosphoethanolamines (GPE), polyunsaturated fatty acids (PUFA), sphingolipids, gangliosides, glycerophospholipids (GPL), and cholesterols, and their connection with α-syn aggregation as well as the induction of innate and adaptive immune reactions that trigger neuroinflammation in PD.

A Comprehensive Review on the Role of the Gut Microbiome in Human Neurological Disorders

The human body is full of an extensive number of commensal microbes, consisting of bacteria, viruses, and fungi, collectively termed the human microbiome. The initial acquisition of microbiota occurs from both the external and maternal environments, and the vast majority of them colonize the gastrointestinal tract (GIT). These microbial communities play a central role in the maturation and development of the immune system, the central nervous system, and the GIT system and are also responsible for essential metabolic pathways. Various factors, including host genetic predisposition, environmental factors, lifestyle, diet, antibiotic or nonantibiotic drug use, etc., affect the composition of the gut microbiota. Recent publications have highlighted that an imbalance in the gut microflora, known as dysbiosis, is associated with the onset and progression of neurological disorders. Moreover, characterization of the microbiome-host cross talk pathways provides insight into novel therapeutic strategies. Novel preclinical and clinical research on interventions related to the gut microbiome for treating neurological conditions, including autism spectrum disorders, Parkinson's disease, schizophrenia, multiple sclerosis, Alzheimer's disease, epilepsy, and stroke, hold significant promise. This review aims to present a comprehensive overview of the potential involvement of the human gut microbiome in the pathogenesis of neurological disorders, with a particular emphasis on the potential of microbe-based therapies and/or diagnostic microbial biomarkers. This review also discusses the potential health benefits of the administration of probiotics, prebiotics, postbiotics, and synbiotics and fecal microbiota transplantation in neurological disorders.

Association between Mediterranean diet and Parkinson’s disease in adults: A systematic review and meta-analysis of cohort studies

BACKGROUND: Parkinson’s disease (PD) is a chronic neurodegenerative disorder, and previous studies have shown that the Mediterranean diet (MeDi) can be effective in reducing the incidence and progression of the disease. OBJECTIVE: The purpose of this study was to determine an association between adherence to MeDi and the risk of PD in adults by meta-analysis of cohort studies. METHODS: Online databases including Scopus, PubMed, Web of Science, and Google Scholar were searched up to March 2021. Cohort studies that examined the association of PD risk with adherence to MeDi were included. A pooled relative risk with a 95% confidence interval was calculated by a random effects meta-analysis. As well, bias assessment, assessment of heterogeneity, sensitivity, and subgroup analyses were carried out. The primary outcome was Parkinson’s incidence. RESULTS: Overall four papers on PD risk were included in the present systematic review and meta-analysis. The effect size of the summary for the risk of overall PD, comparing the highest with the lowest adherence to MeDi, was 0.76 (95% CI: 0.59, 0.98), indicating a significant inverse association. CONCLUSIONS: Adherence to MeDi has a protective role against PD. Also, adhering to this dietary pattern at a younger age may be more beneficial in reducing the risk of PD. However, we suggest more prospective cohort studies in this regard.

Anti-Inflammatory Effect of IKK-Activated GSK-3β Inhibitory Peptide Prevented Nigrostriatal Neurodegeneration in the Rodent Model of Parkinson's Disease

Parkinson’s disease (PD) is a progressive movement disorder caused by nigrostriatal neurodegeneration. Since chronically activated neuroinflammation accelerates neurodegeneration in PD, we considered that modulating chronic neuroinflammatory response might provide a novel therapeutic approach. Glycogen synthase kinase 3 (GSK-3) is a multifunctional serine/threonine protein kinase with two isoforms, GSK-3α and GSK-3β, and GSK-3β plays crucial roles in inflammatory response, which include microglial migration and peripheral immune cell activation. GSK-3β inhibitory peptide (IAGIP) is specifically activated by activated inhibitory kappa B kinase (IKK), and its therapeutic effects have been demonstrated in a mouse model of colitis. Here, we investigated whether the anti-inflammatory effects of IAGIP prevent neurodegeneration in the rodent model of PD. IAGIP significantly reduced MPP⁺-induced astrocyte activation and inflammatory response in primary astrocytes without affecting the phosphorylations of ERK or JNK. In addition, IAGIP inhibited LPS-induced cell migration and p65 activation in BV-2 microglial cells. In vivo study using an MPTP-induced mouse model of PD revealed that intravenous IAGIP effectively prevented motor dysfunction and nigrostriatal neurodegeneration. Our findings suggest that IAGIP has a curative potential in PD models and could offer new therapeutic possibilities for targeting PD.

Cortical excitability changes as a marker of cognitive impairment in Parkinson's disease

Cognitive impairment of different severity with eventual progression to dementia in Parkinson's disease (PD) appears during the course of the disease. In this study, transcranial magnetic stimulation (TMS) was used to assess cortical excitability changes in PD patients with varying cognitive impairment. We aimed to identify the TMS parameters that could serve as a non-invasive marker of cognitive impairment in patients with PD. Consecutive PD patients were recruited in the study. Detailed neuropsychological assessment was carried out to identify PD without cognitive impairment (PD-nC), PD with mild cognitive impairment (PD-MCI) and PD with dementia (PDD). Twenty patients of PDD (2 females and 18 males), 20 PD-MCI (4 females and 16 males), 18 PD-nC (5 females, 13 males) and 18 healthy controls (4 females, and 14 males) were included in the study. All the participants underwent TMS with recording of resting motor threshold, central motor conduction time, silent period, short interval intracortical inhibition (SICI) and intracortical facilitation (ICF). All the groups were age matched. The SICI was present in all; however, significantly greater inhibition was noted in PDD (Mean±SD; 0.11±0.08) followed by PD-MCI (0.31±0.17), PD-nC (0.49±0.26) and controls (0.61±0.23; p<0.001). The ICF was significantly reduced in PDD (Mean±SD; 0.15±0.18), PD-MCI (0.55±0.31), PD-nC (0.96±0.59), when compared to healthy controls (1.81±0.83; p<0.001). Patients with PD-nC, PD-MCI and PDD had graded reduction in ICF and increasing intracortical inhibition as the disease progressed from PD-nC through PD-MCI to PDD. This suggests progressive overactivity of GABAergic transmission, glutaminergic deficiency with consequent reduction of cholinergic transmission leading to dementia.

Evaluation of Inflammatory Cytokine and Anti Helicobacter Pylori Antibodies in the Pathogenesis of Parkinson's Disease

BACKGROUND: Parkinson's disease is a neurodegenerative disorder characterized by degeneration of dopaminergic neurons in the substantia nigari. Previous studies have shown that Helicobacter pylori (H. pylori) infection is associated with treatment and clinical response to Parkinson's disease. In the present study, we aimed to investigate the effect of H. pylori infection in the pathogenesis of Parkinson's disease. METHODS: 75 patients who suffered from Parkinson's disease and H. pylori infection and 91 healthy controls were recruited. All the subjects were evaluated for serum IgM, IgG, and IgA antibodies as well as TNF-α, IL-6, and IL-4 cytokines by Enzyme-Linked ImmunoSorbent Assay (ELISA)methods. RESULTS: The participants included 102 men and 64 women with a mean age of 66±10.2 and 52.6±10.7 years in the patients and control groups, respectively. The level of IgG, TNF-α, IL-6 in the patients with Parkinson's infected with H. pylori was significantly more than that in the control group. In contrast, IgA was significantly lower in patients with Parkinson's disease compared with the control group. CONCLUSION: Probably, persistent infection with H. pylori could be effective in the pathogenesis of Parkinson's disease by dominating the systemic inflammatory profile. It is suggested that pro-inflammatory cytokines followed by H. pylori infection through the promotion of immune response or neurotoxicity might have a role in the pathogenesis of Parkinson's disease.