Non-motor symptoms in patients with Parkinson's disease - correlations with inflammatory cytokines in serum

Rev-erbα regulate neurogenesis through suppression of Sox2 in neuronal cells to regenerate dopaminergic neurons and abates MPP+ induced neuroinflammation

Parkinson's disease is a progressive neurodegenerative disease that affects the motor and non-motor circuits of the brain. Currently, there are no promising therapeutic measures for Parkinson's disease, and most strategies designed to alleviate the Parkinson's disease are palliative. The dearth of therapeutic interventions in Parkinson's disease has driven attention in the search for targets that may augment dopamine secretion, promote differentiation towards dopaminergic neuronal lineage, or aid in neuroprotection from neuronal stress and inflammation, and prevent Parkinson's disease associated motor impairment and behavioural chaos. The study first reports that Rev-erbα plays an important role in regulating the differentiation of undifferentiated neuronal cells towards dopaminergic neurons through abating Sox2 expression in human SH-SY5Y cells. Rev-erbα directly binds to the human Sox2 promoter region and represses their expression to promote differentiation towards dopaminergic neurons. We have reported a novel mechanism of Rev-erbα which effectively abrogates 1-methyl-4-phenylpyridinium induced cytotoxicity, inflammation, and oxidative stress, exerted a beneficial effect on transmembrane potential, and suppressed apoptosis in the neuronal in vitro model of Parkinson's disease. Rev-erbα ligand SR9011 was observed to ease the disease severity in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine induced mouse model of Parkinson's disease. Rev-erbα alleviates the locomotor behavioural impairment, prevents cognitive decline and promotes motor coordination in mice. Administration of Rev-erbα ligand also helps in replenishing the dopaminergic neurons and abrogating the neurotoxin mediated toxicity in an in vitro and in vivo Parkinson's disease model. We conclude that Rev-erbα emerges as a moonlighting nuclear receptor that could be targeted in the treatment and alleviation of Parkinson disease.

Associations Between Neuropsychiatric Symptoms and Inflammation in Neurodegenerative Dementia: A Systematic Review

Background

Neuropsychiatric symptoms are common in dementia and linked to adverse outcomes. Inflammation is increasingly recognized as playing a role as a driver of early disease progression in Alzheimer's disease (AD) and related dementias. Inflammation has also been linked to primary psychiatric disorders, however its association with neuropsychiatric symptoms in neurodegenerative dementias remains uncertain.

Methods

We conducted a systematic literature review investigating associations between inflammation and neuropsychiatric symptoms in neurodegenerative dementias, including AD, Lewy body, Frontotemporal, Parkinson's (PD) and Huntington's disease dementias.

Results

Ninety-nine studies met our inclusion criteria, and the majority (n = 59) investigated AD and/or mild cognitive impairment (MCI). Thirty-five studies included PD, and only 6 investigated non-AD dementias. Inflammation was measured in blood, CSF, by genotype, brain tissue and PET imaging. Overall, studies exhibited considerable heterogeneity and evidence for specific inflammatory markers was inconsistent, with lack of replication and few longitudinal studies with repeat biomarkers. Depression was the most frequently investigated symptom. In AD, some studies reported increases in peripheral IL-6, TNF-a associated with depressive symptoms. Preliminary investigations using PET measures of microglial activation found an association with agitation. In PD, studies reported positive associations between TNF-a, IL-6, CRP, MCP-1, IL-10 and depression.

Conclusion

Central and peripheral inflammation may play a role in neuropsychiatric symptoms in neurodegenerative dementias; however, the evidence is inconsistent. There is a need for multi-site longitudinal studies with detailed assessments of neuropsychiatric symptoms combined with replicable peripheral and central markers of inflammation.

Diagnostic value and correlation analysis of serum cytokine levels in patients with multiple system atrophy

Background

The association between cytokines in peripheral blood and clinical symptoms of multiple system atrophy (MSA) has been explored in only a few studies with small sample size, and the results were obviously controversial. Otherwise, no studies have explored the diagnostic value of serum cytokines in MSA.

Methods

Serum cytokines, including interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor alpha (TNF-α), were measured in 125 MSA patients and 98 healthy controls (HCs). Correlations of these serum cytokines with clinical variables were analyzed in MSA patients. Diagnostic value of cytokines for MSA was plotted by receiver operating curves.

Results

No significant differences were found in sex and age between the MSA group and the HCs. TNF-α in MSA patients were significantly higher than those in HCs (area under the curve (AUC) 0.768), while IL-6 and IL-8 were not. Only Hamilton Anxiety Scale (HAMA) has a positive correlation between with TNF-α in MSA patients with age and age at onset as covariates. Serum IL-6 was associated with HAMA, Hamilton Depression Scale (HAMD), the Unified MSA Rating Scale I (UMSARS I) scores, the UMSARS IV and the Instrumental Activity of Daily Living scores. However, IL-8 was not associated with all clinical variables in MSA patients. Regression analysis showed that HAMA and age at onset were significantly associated with TNF-α, and only HAMA was mild related with IL-6 levels in MSA patients.

Conclusion

Serum TNF-α and IL-6 levels in MSA patients may be associated with anxiety symptom; however, only TNF-α was shown to be a useful tool in distinguishing between MSA and HCs.

Alpha Synuclein Toxicity and Non-Motor Parkinson's

Parkinson's disease (PD) is a common multisystem neurodegenerative disorder affecting 1% of the population over the age of 60 years. The main neuropathological features of PD are the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the presence of alpha synuclein (αSyn)-rich Lewy bodies both manifesting with classical motor signs. αSyn has emerged as a key protein in PD pathology as it can spread through synaptic networks to reach several anatomical regions of the body contributing to the appearance of non-motor symptoms (NMS) considered prevalent among individuals prior to PD diagnosis and persisting throughout the patient's life. NMS mainly includes loss of taste and smell, constipation, psychiatric disorders, dementia, impaired rapid eye movement (REM) sleep, urogenital dysfunction, and cardiovascular impairment. This review summarizes the more recent findings on the impact of αSyn deposits on several prodromal NMS and emphasizes the importance of early detection of αSyn toxic species in biofluids and peripheral biopsies as prospective biomarkers in PD.

A neurotherapeutic approach with Lacticaseibacillus rhamnosus E9 on gut microbiota and intestinal barrier in MPTP-induced mouse model of Parkinson's disease

The gut microbiota plays a crucial role in neural development and progression of neural disorders like Parkinson's disease (PD). Probiotics have been suggested to impact neurodegenerative diseases via gut-brain axis. This study aims to investigate the therapeutic potential of Lacticaseibacillus rhamnosus E9, a high exopolysaccharide producer, on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced mouse model of PD. C57BL/6 mice subjected to MPTP were fed L. rhamnosus E9 for fifteen days and sacrificed after the last administration. Motor functions were determined by open-field, catalepsy, and wire-hanging tests. The ileum and the brain tissues were collected for ELISA, qPCR, and immunohistochemistry analyses. The cecum content was obtained for microbiota analysis. E9 supplementation alleviated MPTP-induced motor dysfunctions accompanied by decreased levels of striatal TH and dopamine. E9 also reduced the level of ROS in the striatum and decreased the DAT expression while increasing the DR1. Furthermore, E9 improved intestinal integrity by enhancing ZO-1 and Occludin levels and reversed the dysbiosis of the gut microbiota induced by MPTP. In conclusion, E9 supplementation improved the MPTP-induced motor deficits and neural damage as well as intestinal barrier by modulating the gut microbiota in PD mice. These findings suggest that E9 supplementation holds therapeutic potential in managing PD through the gut-brain axis.

Associations of inflammatory cytokines and cortisol with nonmotor features of Huntington's disease

OBJECTIVE

Huntington's disease (HD) is an inherited neurodegenerative disease involving progressive motor abnormalities, cognitive decline, and psychiatric disturbances. Depression and cognitive difficulties are among the most impactful symptoms of HD, yet the pathogenesis of these symptoms is not fully understood. HD involves low-level chronic inflammation and dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which are linked to depression and cognitive impairment in non-HD populations. However, previous research on the relationships of these pathologies with depression and cognition in HD is limited and inconsistent.

METHODS

Fifty-three adults with the HD gene expansion (30 premanifest and 23 manifest) completed measures of depression and cognitive functioning. Forty-eight out of 53 participants provided hair samples for quantification of cortisol, and 34 participants provided blood samples for quantification of peripheral inflammatory cytokines. We examined the associations of four cytokines (interleukin [IL]-6, IL-10, IL-1β, and tumor necrosis factor [TNF]-α) and cortisol levels with depression and cognitive scores.

RESULTS

In unadjusted models, higher levels of plasma IL-6, IL-10, and TNF-α correlated with higher depression scores, and higher levels of IL-10 and TNF-α correlated with poorer cognitive performance. After controlling for age, sex, and body mass index, only the correlations of IL-10 with depression and cognitive performance remained significant. No correlations were evident with hair cortisol.

INTERPRETATIONS

Peripheral inflammation is associated with depression symptoms and cognitive impairment in HD. Our findings suggest that interactions between the immune and nervous systems are important in HD, and highlight the potential of chronic inflammation as a therapeutic target in early stages of HD.

Inflammation and Neurodegeneration in Glaucoma: Isolated Eye Disease or a Part of a Systemic Disorder? - Serum Proteomic Analysis

Introduction

Glaucoma is the most common optic neuropathy and the leading cause of irreversible blindness worldwide, which affects 3.54% of the population aged 40-80 years. Despite numerous published studies, some aspects of glaucoma pathogenesis, serum biomarkers, and their potential link with other diseases remain unclear. Recent articles have proposed that autoimmune, oxidative stress and inflammation may be involved in the pathogenesis of glaucoma.

Methods

We investigated the serum expression of 92 inflammatory and neurotrophic factors in glaucoma patients. The study group consisted of 26 glaucoma patients and 192 healthy subjects based on digital fundography.

Results

Patients with glaucoma had significantly lower serum expression of IL-2Rβ, TWEAK, CX3CL1, CD6, CD5, LAP TGF-beta1, LIF-R, TRAIL, NT-3, and CCL23 and significantly higher expression of IL-22Rα1.

Conclusion

Our results indicate that patients with glaucoma tend to have lower levels of neuroprotective proteins and higher levels of neuroinflammatory proteins, similar to those observed in psychiatric, neurodegenerative and autoimmune diseases, indicating a potential link between these conditions and glaucoma pathogenesis.

Increased plasma lipocalin-2 levels are associated with nonmotor symptoms and neuroimaging features in patients with Parkinson's disease

Lipocalin-2 (LCN2) is essential for the regulation of neuroinflammation and cellular uptake of iron. This study aimed to evaluate plasma LCN2 levels and explore their correlation with clinical and neuroimaging features in Parkinson's disease (PD) patients. Enzyme-linked immunosorbent assay (ELISA) was used to measure plasma LCN2 levels in 120 subjects. Evaluation of motor symptoms and nonmotor symptoms in PD patients was assessed by the associated scales. Voxel-based morphometry (VBM) was used to evaluate brain volume alterations, and quantitative susceptibility mapping (QSM) was used to quantitatively analyze brain iron deposition in 46 PD patients. Plasma LCN2 levels were significantly higher in PD patients than those in healthy controls. LCN2 levels were negatively correlated with Montreal Cognitive Assessment (MoCA) scores, total brain gray matter volume (GMV), and GMV/total intracranial volume (TIV) ratio, but positively correlated with Hamilton Anxiety Rating Scale (HAMD) scores and mean QSM values of the bilateral substantial nigra (SN). Receiver operating characteristic (ROC) curves confirmed that plasma LCN2 levels had good predictive accuracy for PD. The results suggest that plasma LCN2 levels have potential as a biomarker for the diagnosis of PD. LCN2 may be a therapeutic target for neuroinflammation and brain iron deposition.

The molecular mechanism of aging and the role in neurodegenerative diseases

Aging is a complex and inevitable biological process affected by a combination of external environmental and genetic factors. Humans are currently living longer than ever before, accompanied with aging-related alterations such as diminished autophagy, decreased immunological function, mitochondrial malfunction, stem cell failure, accumulation of somatic and mitochondrial DNA mutations, loss of telomere, and altered nutrient metabolism. Aging leads to a decline in body functions and age-related diseases, for example, Alzheimer's disease, which adversely affects human health and longevity. The quality of life of the elderly is greatly diminished by the increase in their life expectancy rather than healthy life expectancy. With the rise in the age of the global population, aging and related diseases have become the focus of attention worldwide. In this review, we discuss several major mechanisms of aging, including DNA damage and repair, free radical oxidation, telomeres and telomerase, mitochondrial damage, inflammation, and their role in neurodegenerative diseases to provide a reference for the prevention of aging and its related diseases.

Effect of Transcranial Direct Current Stimulation (tDCS) on Depression in Parkinson's Disease-A Narrative Review

INTRODUCTION

Depression is the most prevalent comorbid neuropsychiatric condition in individuals with Parkinson's disease (PD), and its underlying mechanisms are not yet fully understood. Current treatment methods are characterised by moderate effectiveness and possible side effects, prompting the search for new non-invasive and safe treatment methods.

METHODS

This narrative review explores the use of transcranial direct current stimulation (tDCS) in the treatment of depression in PD, based on neuropsychological measures. Searches were conducted in the PubMed/Medline, Research Gate, and Cochrane databases.

RESULTS

Nine relevant studies were identified, where depression scores served as either primary or secondary outcomes. Stimulation protocols displayed heterogeneity, especially concerning choice of stimulation site. Patient samples were also heterogeneous. The majority of the studies incorporated anodal stimulation targeting the left dorsolateral prefrontal cortex (DLPFC). The results revealed a reduction in depression scores among PD patients following tDCS. Potential mechanisms through which tDCS may alleviate depression in PD were discussed and recommendations for future research were made.

CONCLUSIONS

Preliminary evidence suggests that tDCS applied anodally to the left DLPFC reduces depression scores in people with PD; however, due to the heterogeneity of the studies analysed, the use of tDCS in this field should be approached with caution and warrants further validation and confirmation.

Targeted Treatment Strategies for Mitochondria Dysfunction: Correlation with Neurological Disorders

Mitochondria are an essential intracellular organelle for medication targeting and delivery since they seem to create energy and conduct many other cellular tasks, and mitochondrial dysfunctions and malfunctions lead to many illnesses. Many initiatives have been taken to detect, diagnose, and image mitochondrial abnormalities, and to transport and accumulate medicines precisely to mitochondria, all because of special mitochondrial aspects of the pathophysiology of cancer. In addition to the negative membrane potential and paradoxical mitochondrial dynamics, they include high temperatures, high levels of reactive oxygen species, high levels of glutathione, and high temperatures. Neurodegenerative diseases represent a broad spectrum of debilitating illnesses. They are linked to the loss of certain groups of neurons based on an individual's physiology or anatomy. The mitochondria in a cell are generally accepted as the authority with respect to ATP production. Disruption of this system is linked to several cellular physiological issues. The development of neurodegenerative disorders has been linked to mitochondrial malfunction, according to pathophysiological studies. There seems to be substantial evidence connecting mitochondrial dysfunction and oxidative stress to the development of neurodegenerative disorders. It has been extensively observed that mitochondrial malfunction triggers autophagy, which plays a role in neurodegenerative disorders. In addition, excitotoxicity and mitochondrial dysfunction have been linked to the development of neurodegenerative disorders. The pathophysiology of neurodegenerative illnesses has been linked to increased apoptosis and necrosis, as well as mitochondrial malfunction. A variety of synthetic and natural treatments have shown efficacy in treating neurodegenerative illnesses caused by mitochondrial failure. Neurodegenerative illnesses can be effectively treated with existing drugs that target mitochondria, although their precise formulations are poorly understood. Therefore, there is an immediate need to focus on creating drug delivery methods specifically targeted at mitochondria in the treatment and diagnosis of neurodegenerative disorders.

Plasma TNF-α and phosphorylated α-syn are associated with fatigue in patients with Parkinson's disease

BACKGROUD

Fatigue is one of the most common non-motor symptoms among patients with Parkinson's disease (PD).However, the pathogenesis keeps largely unknown. Moreover, it is lack of objective biomarker.

OBJECTIVE

To investigate the relationship between plasma inflammatory cytokines and α-syn levels and fatigue in patients with PD.

METHODS

A total of 63 PD patients were enrolled, including 35 patients with fatigue and 28 patients without fatigue. We compared the difference between plasma cytokines and alpha-synuclein (α-syn) in the two groups. Meanwhile, we analyzed the relationship between plasma cytokines and p-α-syn levels and fatigue.

RESULTS

PD patients with fatigue had older age, longer disease duration, more severe motor scores. There were significant differences in the plasma levels of IL-1β, IL-18, TNF-α, and phosphorylated α-syn (p-α-syn) between the two groups. The plasm inflammatory cytokine levels (IL-1β, IL-18 and TNF-α) were positively associated with FSS scores. Moreover, the plasma p-α-syn level was significantly positively correlated with FSS scores. Furthermore, the higher PDQ-39 scores and higher plasma levels of TNF-α and p-α-syn were strongly associated with fatigue in PD. The ROC curve analysis showed the AUC of TNF-α for fatigue in PD was 0.663 with a sensitivity of 65.71% and specificity of 67.86%, while the AUC of p-α-syn was 0.786 with a sensitivity of 74.29% and specificity of 64.29%. The combination of TNF-α and p-α-syn improves the AUC to 0.803 with a sensitivity of 88.57% and specificity of 64.29%.

CONCLUSION

The high plasma levels of TNF-α and p-α-syn were strongly associated with fatigue in PD.

How should we be using biomarkers in trials of disease modification in Parkinson's disease?

The recent validation of the α-synuclein seed amplification assay as a biomarker with high sensitivity and specificity for the diagnosis of Parkinson's disease has formed the backbone for a proposed staging system for incorporation in Parkinson's disease clinical studies and trials. The routine use of this biomarker should greatly aid in the accuracy of diagnosis during recruitment of Parkinson's disease patients into trials (as distinct from patients with non-Parkinson's disease parkinsonism or non-Parkinson's disease tremors). There remain, however, further challenges in the pursuit of biomarkers for clinical trials of disease modifying agents in Parkinson's disease, namely: optimizing the distinction between different α-synucleinopathies; the selection of subgroups most likely to benefit from a candidate disease modifying agent; a sensitive means of confirming target engagement; and the early prediction of longer-term clinical benefit. For example, levels of CSF proteins such as the lysosomal enzyme β-glucocerebrosidase may assist in prognostication or allow enrichment of appropriate patients into disease modifying trials of agents with this enzyme as the target; the presence of coexisting Alzheimer's disease-like pathology (detectable through CSF levels of amyloid-β42 and tau) can predict subsequent cognitive decline; imaging techniques such as free-water or neuromelanin MRI may objectively track decline in Parkinson's disease even in its later stages. The exploitation of additional biomarkers to the α-synuclein seed amplification assay will, therefore, greatly add to our ability to plan trials and assess the disease modifying properties of interventions. The choice of which biomarker(s) to use in the context of disease modifying clinical trials will depend on the intervention, the stage (at risk, premotor, motor, complex) of the population recruited and the aims of the trial. The progress already made lends hope that panels of fluid biomarkers in tandem with structural or functional imaging may provide sensitive and objective methods of confirming that an intervention is modifying a key pathophysiological process of Parkinson's disease. However, correlation with clinical progression does not necessarily equate to causation, and the ongoing validation of quantitative biomarkers will depend on insightful clinical-genetic-pathophysiological comparisons incorporating longitudinal biomarker changes from those at genetic risk with evidence of onset of the pathophysiology and those at each stage of manifest clinical Parkinson's disease.

The Utility of Methylphenidate for Fatigue in Long-Term Neurological Conditions: A Meta-analytical Review

OBJECTIVE

Fatigue is a chronic and debilitating symptom of many long-term neurological conditions (LTNCs). Although methylphenidate provides some promise in alleviating fatigue in other clinical groups, little work has explored its potential utility within LTNCs. The current systematic review and meta-analysis evaluates the utility of methylphenidate for symptoms of fatigue in LTNCs.

METHODS

Five databases (PsycINFO, MEDLINE, Embase, Scopus, and Cochrane Library) were searched for relevant articles from their inception to February 2022. A purpose-developed evaluation tool was used to assess each study's research quality (QuEST:F).

RESULTS

Of the 1698 articles identified, 11 articles were included within this review (n = 370). Meta-analytical findings reported an overall significant benefit of methylphenidate for symptoms of fatigue across a mixed neurological sample ( g = -0.44; 95% confidence interval, -0.77 to -0.11). Subgroup analyses identified a significantly greater benefit ( P < 0.001) of methylphenidate for fatigue in LTNCs with static pathogenic trajectories (eg, traumatic brain injury) (number needed to treat = 2.5) compared with progressive conditions (eg, multiple sclerosis) (number needed to treat = 40.2).

CONCLUSIONS

Methylphenidate may pose an effective intervention for the treatment of fatigue in a number of LTNCs. Nonetheless, given the quality of the current evidence base, there exists a clear need for further robust assessment of the utility of methylphenidate-with a focus on subgroup-specific variability.

Effect of Zishen pingchan granules combined with pramipexole on serum BDNF, IL-1β, IL-6, CRP, TNF-α levels in depressed patients with Parkinson's disease: Results of a randomized, double-blind, controlled study

INTRODUCTION

Depression is a common comorbidity in Parkinson's Disease (PD) and treatment of depression can significantly support PD management. Zishen pingchan granules (ZPG), a traditional Chinese herbal formula, may help ameliorate depressive symptoms in PD patients. However, the molecular mechanisms underlying the effects of ZPG remain unclear. This study aimed to investigate the impact of ZPG on serum levels of brain-derived neurotrophic factor (BDNF), interleukin-1β (IL-1β), interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor-α (TNF-α) in PD patients with depression.

METHODS

Eighty PD patients treated with pramipexole but still experiencing mild to moderate depression symptoms were randomly allocated to a group receiving 12-week ZPG treatment (n = 40) or placebo (n = 40). The Hamilton Depression Scale 17 items (HAM-D-17) was utilized to evaluate changes in depressive symptoms from baseline over 12 weeks, while the Unified Parkinson's Disease Rating Scales (UPDRS) part 3 was employed to assess changes in motor symptoms over the same duration. Serum levels of BDNF, IL-1β, IL-6, CRP, and TNF-α were measured at baseline and post-treatment.

RESULTS

Seventy-one participants completed the study. Following treatment, both groups showed significantly reduced HAMD scores. The placebo group demonstrated a decrease in BDNF levels, while the ZPG group showed an increase in IL-6 levels post-treatment. In the examination of the group-time interaction, the ZPG group exhibited a greater decrease in HAMD scores and increase in IL-6 levels compared to the placebo group. Conversely, the placebo group showed a greater decrease in BDNF levels compared to the ZPG group. However, no significant group differences were observed in UPDRS part 3 change scores or serum levels of IL-1β, CRP, or TNF-α change from baseline.

CONCLUSION

ZPG may potentially ameliorate depressive symptoms in PD patients, with the potential mechanism involving mitigation of reductions in serum BDNF level and an increase in IL-6 level.

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.

The Molecular Mechanisms of the Relationship between Insulin Resistance and Parkinson's Disease Pathogenesis

Parkinson's disease (PD) is a degenerative condition resulting from the loss of dopaminergic neurons. This neuronal loss leads to motor and non-motor neurological symptoms. Most PD cases are idiopathic, and no cure is available. Recently, it has been proposed that insulin resistance (IR) could be a central factor in PD development. IR has been associated with PD neuropathological features like α-synuclein aggregation, dopaminergic neuronal loss, neuroinflammation, mitochondrial dysfunction, and autophagy. These features are related to impaired neurological metabolism, neuronal death, and the aggravation of PD symptoms. Moreover, pharmacological options that involve insulin signaling improvement and dopaminergic and non-dopaminergic strategies have been under development. These drugs could prevent the metabolic pathways involved in neuronal damage. All these approaches could improve PD outcomes. Also, new biomarker identification may allow for an earlier PD diagnosis in high-risk individuals. This review describes the main pathways implicated in PD development involving IR. Also, it presents several therapeutic options that are directed at insulin signaling improvement and could be used in PD treatment. The understanding of IR molecular mechanisms involved in neurodegenerative development could enhance PD therapeutic options and diagnosis.

Pharmacological and Non-Pharmacological Treatments for Depression in Parkinson's Disease: An Updated Review

Depression represents one of the most common non-motor disorders in Parkinson's disease (PD) and it has been related to worse life quality, higher levels of disability, and cognitive impairment, thereby majorly affecting not only the patients but also their caregivers. Available pharmacological therapeutic options for depression in PD mainly include selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, and tricyclic antidepressants; meanwhile, agents acting on dopaminergic pathways used for motor symptoms, such as levodopa, dopaminergic agonists, and monoamine oxidase B (MAO-B) inhibitors, may also provide beneficial antidepressant effects. Recently, there is a growing interest in non-pharmacological interventions, including cognitive behavioral therapy; physical exercise, including dance and mind-body exercises, such as yoga, tai chi, and qigong; acupuncture; therapeutic massage; music therapy; active therapy; repetitive transcranial magnetic stimulation (rTMS); and electroconvulsive therapy (ECT) for refractory cases. However, the optimal treatment approach for PD depression is uncertain, its management may be challenging, and definite guidelines are also lacking. It is still unclear which of these interventions is the most appropriate and for which PD stage under which circumstances. Herein, we aim to provide an updated comprehensive review of both pharmacological and non-pharmacological treatments for depression in PD, focusing on recent clinical trials, systematic reviews, and meta-analyses. Finally, we discuss the pharmacological agents that are currently under investigation at a clinical level, as well as future approaches based on the pathophysiological mechanisms underlying the onset of depression in PD.

Gut Microbial Alteration in MPTP Mouse Model of Parkinson Disease is Administration Regimen Dependent

Parkinson Disease (PD) is one of the most common neurodegenerative disorders characterized by loss of dopaminergic neurons involved in motor functions. Growing evidence indicates that gut microbiota communicates with the brain known as the gut-brain axis (GBA). Mitochondrial toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is commonly used in animal studies to investigate the GBA in PD. Various MPTP administration regimens are performed in PD mouse models involving one to multiple injections in 1 day or one injection per day for several days. The aim of this study is to investigate if the impact of MPTP on gut microbiota differs depending on the administration regimen. C57BL/6 mice were treated with acute or subchronic regimens of MPTP. Motor functions were assessed by open-field, catalepsy, and wire hanging tests. The cecum and the brain samples were obtained for microbiota and gene expression analyses, respectively. MPTP administration regimens differed in their ability to alter the gut microbiota. Firmicutes and Bacteroidota were both increased in subchronic mice while did not change and decreased, respectively, in acute mice. Verrucomicrobiota was elevated in acute MPTP mice but dropped in subchronic MPTP mice. Muribaculaceae was the predominant genus in all groups but acute mice. In acute mice, Akkermansia was increased and Colidextribacter was decreased; however, they showed an opposite trend in subchronic mice. These data suggest that MPTP mouse model cause a gut microbiota dysbiosis in an administration regimen dependent manner, and it is important to take consideration of mouse model to investigate the GBA in neurodegenerative diseases including PD.

Inflammatory Bowel Disease and Neurodegenerative Diseases

A growing body of evidence has demonstrated an intricate association between inflammatory bowel disease (IBD) and neurodegenerative conditions, expanding beyond previous foci of comorbidities between IBD and mood disorders. These new discoveries stem from an improved understanding of the gut-microbiome-brain axis: specifically, the ability of the intestinal microbiota to modulate inflammation and regulate neuromodulatory compounds. Clinical retrospective studies incorporating large sample sizes and population-based cohorts have demonstrated and confirmed the relevance of IBD and chronic neurodegeneration in clinical medicine. In this review, we expound upon the current knowledge on the gut-microbiome-brain axis, highlighting several plausible mechanisms linking IBD with neurodegeneration. We also summarize the known associations between IBD with Parkinson disease, Alzheimer disease, vascular dementia and ischemic stroke, and multiple sclerosis in a clinical context. Finally, we discuss the implications of an improved understanding of the gut-microbiome-brain axis in preventing, diagnosing, and managing neurodegeneration among IBD and non-IBD patients.

The old second messenger cAMP teams up with novel cell death mechanisms: potential translational therapeutical benefit for Alzheimer's disease and Parkinson's disease

Alzheimer's disease (AD) and Parkinson's disease (PD) represent the most prevalent neurodegenerative disorders severely impacting life expectancy and quality of life of millions of people worldwide. AD and PD exhibit both a very distinct pathophysiological disease pattern. Intriguingly, recent researches, however, implicate that overlapping mechanisms may underlie AD and PD. In AD and PD, novel cell death mechanisms, encompassing parthanatos, netosis, lysosome-dependent cell death, senescence and ferroptosis, apparently rely on the production of reactive oxygen species, and seem to be modulated by the well-known, "old" second messenger cAMP. Signaling of cAMP via PKA and Epac promotes parthanatos and induces lysosomal cell death, while signaling of cAMP via PKA inhibits netosis and cellular senescence. Additionally, PKA protects against ferroptosis, whereas Epac1 promotes ferroptosis. Here we review the most recent insights into the overlapping mechanisms between AD and PD, with a special focus on cAMP signaling and the pharmacology of cAMP signaling pathways.

Trimethylamine N-oxide: role in cell senescence and age-related diseases

INTRODUCTION

Hayflick and Moorhead first demonstrated cell senescence as the irreversible growth arrest of cells after prolonged cultivation. Telomere shortening and oxidative stress are the fundamental mechanisms that drive cell senescence. Increasing studies have shown that TMAO is closely associated with cellular aging and age-related diseases. An emerging body of evidence from animal models, especially mice, has identified that TMAO contributes to senescence from multiple pathways and appears to accelerate many neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. However, the specific mechanism of how TMAO speeds aging is still not completely clear.

MATERIAL AND METHODS

In this review, we summarize some key findings in TMAO, cell senescence, and age-related diseases. We focused particular attention on the potential mechanisms for clinical transformation to find ways to interfere with the aging process.

CONCLUSION

TMAO can accelerate cell senescence by causing mitochondrial damage, superoxide formation, and promoting the generation of pro-inflammatory factors.

Neurobiology of depression in Parkinson's disease: Insights into epidemiology, molecular mechanisms and treatment strategies

Parkinson's disease (PD) is characterized mainly by motor dysfunctions due to the progressive loss of dopaminergic neurons. However, PD patients experience a multitude of debilitating non-motor symptoms, including depression, which may have deleteriously detrimental effects on life. Depression is multifactorial and exhibits a bimodal progression in PD, but its underlying molecular mechanisms are poorly understood. Studies demonstrating the pathophysiology of depression in PD and the specific treatment strategies for depression-like symptoms in PD patients are largely lacking, often underrated, under-recognized and, consequently, inadequately/under-treated. Nevertheless, reports suggest that the incidence of depression is approximately 20-30% of PD patients and may precede the onset of motor symptoms. Diagnosing depression in PD becomes difficult due to the clinical overlap in symptomatology between the two diseases, and the nigrostriatal dysfunction alone is insufficient to explain depressive symptoms in PD. Therefore, the current study provides an overview of the molecular mechanisms underlying the development of depression in PD and new insights into developing current antidepressant strategies to treat depression in PD. This review will identify and understand the molecular pathological mechanisms of depression in PD that will fundamentally help tailoring therapeutic interventions for depressive symptoms in PD.

Biomarkers of sleep disturbance in adults with chronic illness: A scoping review

OBJECTIVES

The purpose of this scoping review was to identify which biomarkers for sleep disturbance were the most prevalent and significant in the literature across chronic illnesses.

METHODS

A scoping review was conducted, following Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines, to provide a map of the existing literature on the biomarkers of sleep disturbance in adults with chronic illness. Peer-reviewed articles published between 2010-2020 were included if they measured a biomarker and discussed sleep deprivation, disturbance, or dysfunction secondary to a chronic illness.

RESULTS

A total of 21 articles were included and synthesized using data charting. There were 24 different biomarkers identified, most commonly collected through serum. Biomarkers were grouped, then biomarkers and correlations with sleep were identified and mapped.

DISCUSSION

Overall, the most common biomarkers studied were interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), c-reactive protein (CRP), and interleukin-1 beta (IL-1β). Cytokines were the most commonly studied biomarkers, with a majority of studies focusing on pro-inflammatory cytokines. Based on the results of this review, CRP, IL-6, TNF-α, and erythrocyte sedimentation rate (ESR) showed themost significant correlations with sleep across all chronic illnesses. Future research is still needed to identify an ideal biomarker for sleep disturbance that can be used across chronic illnesses.

Blood Biomarkers in Patients with Parkinson's Disease: A Review in Context of Anesthetic Care

Parkinson's disease (PD) is the second most common inflammatory neurodegenerative disorder after dementia. Preclinical and epidemiological data strongly suggest that chronic neuroinflammation slowly induces neuronal dysfunction. Activated microglia secrete several neurotoxic substances, such as chemokines and proinflammatory cytokines, which may promote blood-brain barrier (BBB) permeabilization. CD4⁺ T cells comprise proinflammatory cells such as T helper (Th) 1 and Th17 cells, as well as anti-inflammatory cells such as Th2 and T regulatory cells (Tregs). Th1 and Th17 cells can be detrimental to dopamine neurons, whereas Th2 and Tregs are neuroprotective. The results of studies on the serum levels of cytokines such as IFN-γ and TNF-α secreted by Th1 T cells, IL-8 and IL-10 secreted by Th2 T cells, and IL-17 secreted by Th17 cells in PD patients are not uniform. In addition, the relationships between serum cytokine levels and motor and non-motor symptoms of PD are controversial. Surgical stress and anesthesia induce inflammatory responses by disturbing the balance between pro- and anti-inflammatory cytokines, which may exacerbate the neuroinflammatory response in PD patients. Here we review studies on blood inflammatory biomarkers in PD patients and discuss the roles of surgery and anesthesia in PD progression.

Therapeutic modulation of JAK-STAT, mTOR, and PPAR-γ signaling in neurological dysfunctions

The cytokine-activated Janus kinase (JAK)-signal transducer and activator of transcription (STAT) cascade is a pleiotropic pathway that involves receptor subunit multimerization. The mammalian target of rapamycin (mTOR) is a ubiquitously expressed serine-threonine kinase that perceives and integrates a variety of intracellular and environmental stimuli to regulate essential activities such as cell development and metabolism. Peroxisome proliferator-activated receptor-gamma (PPARγ) is a prototypical metabolic nuclear receptor involved in neural differentiation and axon polarity. The JAK-STAT, mTOR, and PPARγ signaling pathways serve as a highly conserved signaling hub that coordinates neuronal activity and brain development. Additionally, overactivation of JAK/STAT, mTOR, and inhibition of PPARγ signaling have been linked to various neurocomplications, including neuroinflammation, apoptosis, and oxidative stress. Emerging research suggests that even minor disruptions in these cellular and molecular processes can have significant consequences manifested as neurological and neuropsychiatric diseases. Of interest, target modulators have been proven to alleviate neuronal complications associated with acute and chronic neurological deficits. This research-based review explores the therapeutic role of JAK-STAT, mTOR, and PPARγ signaling modulators in preventing neuronal dysfunctions in preclinical and clinical investigations.

Investigating Therapeutic Effects of Indole Derivatives Targeting Inflammation and Oxidative Stress in Neurotoxin-Induced Cell and Mouse Models of Parkinson's Disease

Neuroinflammation and oxidative stress have been emerging as important pathways contributing to Parkinson's disease (PD) pathogenesis. In PD brains, the activated microglia release inflammatory factors such as interleukin (IL)-β, IL-6, tumor necrosis factor (TNF)-α, and nitric oxide (NO), which increase oxidative stress and mediate neurodegeneration. Using 1-methyl-4-phenylpyridinium (MPP⁺)-activated human microglial HMC3 cells and the sub-chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD, we found the potential of indole derivative NC009-1 against neuroinflammation, oxidative stress, and neurodegeneration for PD. In vitro, NC009-1 alleviated MPP⁺-induced cytotoxicity, reduced NO, IL-1β, IL-6, and TNF-α production, and suppressed NLR family pyrin domain containing 3 (NLRP3) inflammasome activation in MPP⁺-activated HMC3 cells. In vivo, NC009-1 ameliorated motor deficits and non-motor depression, increased dopamine and dopamine transporter levels in the striatum, and reduced oxidative stress as well as microglia and astrocyte reactivity in the ventral midbrain of MPTP-treated mice. These protective effects were achieved by down-regulating NLRP3, CASP1, iNOS, IL-1β, IL-6, and TNF-α, and up-regulating SOD2, NRF2, and NQO1. These results strengthen the involvement of neuroinflammation and oxidative stress in PD pathogenic mechanism, and indicate NC009-1 as a potential drug candidate for PD treatment.

Serum inflammatory cytokines levels and the correlation analyses in Parkinson's disease

Objective: To investigate the serum levels of inflammatory cytokines and the correlations with Parkinson's disease (PD) clinical symptoms. Methods: Serum levels of the cytokines, including IL-6, IL-8, and TNF-α, were measured in 273 PD patients and 91 healthy controls (HCs). The clinical manifestations of PD were assessed with nine different scales to evaluate the cognitive function, non-motor symptoms, motor symptoms, and disease severity. The differences in these inflammatory indicators were examined between PD patients and HCs, and the correlations of these inflammatory indicators with clinical variables were analyzed in PD patients. Results: Serum levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in PD patients were higher than those in HCs, but serum interleukin-8 (IL-8) level was not significantly different from that in HCs. In PD patients, serum IL-6 level was positively correlated with age of onset, the Hamilton Depression Scale (HAMD), and the Non-Motor Symptom Scale (NMSS), UPDRS part I, part II, and part III, but it was inversely correlated with the Frontal Assessment Battery (FAB) and the Montreal Cognitive Assessment (MoCA) scores. Serum TNF-α level was positively correlated with age of onset and H&Y stage in PD patients (p = .037), but negatively correlated with FAB scores in PD patients (p = .010). However, no associations were found between all the clinical variables and the serum IL-8 level. The forward binary logistic regression model revealed that serum IL-6 level was associated with MoCA (p = .023) and UPDRS I scores (p = .023), but no associations was found with the remaining factors. The ROC curve of TNF-α for the diagnosis of PD showed the area under the curve (AUC) was .719 (p < .05, 95% CI: .655-.784), and the critical value of TNF-α was 5.380 pg/ml, with a diagnostic sensitivity of 76.0% and a specificity of 59.3%. Conclusion: Our results suggest increased serum levels of IL-6 and TNF-α in PD, we further found that IL-6 level was associated with non-motor symptoms and cognitive dysfunction, and IL-6 may play a role in the pathophysiology of non-motor symptoms in PD. At the same time, we also propose that TNF-α has a good diagnostic value for PD despite its irrelevance to clinical symptoms.

The complex role of inflammation and gliotransmitters in Parkinson's disease

Our understanding of the role of innate and adaptive immune cell function in brain health and how it goes awry during aging and neurodegenerative diseases is still in its infancy. Inflammation and immunological dysfunction are common components of Parkinson's disease (PD), both in terms of motor and non-motor components of PD. In recent decades, the antiquated notion that the central nervous system (CNS) in disease states is an immune-privileged organ, has been debunked. The immune landscape in the CNS influences peripheral systems, and peripheral immunological changes can alter the CNS in health and disease. Identifying immune and inflammatory pathways that compromise neuronal health and survival is critical in designing innovative and effective strategies to limit their untoward effects on neuronal health.

Peripheral Inflammatory Markers TNF-α and CCL2 Revisited: Association with Parkinson's Disease Severity

One of the major mediators of neuroinflammation in PD is tumour necrosis factor alpha (TNF-α), which, similar to other cytokines, is produced by activated microglia and astrocytes. Although TNF-α can be neuroprotective in the brain, long-term neuroinflammation and TNF release can be harmful, having a neurotoxic role that leads to death of oligodendrocytes, astrocytes, and neurons and, therefore, is associated with neurodegeneration. Apart from cytokines, a wide family of molecules with homologous structures, namely chemokines, play a key role in neuro-inflammation by drawing cytotoxic T-lymphocytes and activating microglia. The objective of the current study was to examine the levels of the serum TNF-α and CCL2 (Chemokine (C-C motif) ligand 2), also known as MCP-1 (Monocyte Chemoattractant Protein-1), in PD patients compared with healthy controls. We also investigated the associations between the serum levels of these two inflammatory mediators and a number of clinical symptoms, in particular, disease severity and cognition. Such an assessment may point to their prognostic value and provide some treatment hints. PD patients with advanced stage on the Hoehn-Yahr scale showed an increase in TNF-α levels compared with PD patients with stages 1 and 2 (p = 0.01). Additionally, the UPDRS score was significantly associated with TNF-α levels. CCL2 levels, however, showed no significant associations.

Inflammatory markers and depression in Parkinson's disease: a systematic review

BACKGROUND

Parkinson's disease (PD) patients experience non-motor symptoms (NMS), which may appear before motor manifestations. The most common NMS is depression, affecting about 30-40% of PD patients. Both PD and depression are associated with an increased inflammatory burden, with studies showing elevation of diverse inflammatory markers in patients with both conditions.

METHODS

A systematic review was conducted in PubMed and PsycINFO databases to investigate what inflammatory markers are associated with PD depression (PDD). Only studies in English that measured inflammatory markers and analyzed against depression scores in PD patients were included.

RESULTS

A total of 1132 articles were retrieved, and 14 entries were found to be eligible. Twelve were cross-sectional studies, one was a cohort, and one was a non-randomized controlled trial. IL-17A was the only marker strongly associated with PDD, while studies assessing sIL-2R and serum amyloid A found a moderate correlation. C-reactive protein, IL-10, tumor necrosis factor-α, monocyte chemoattractant protein-1, and IL-6 yielded conflicting results. Their possible roles in PDD are discussed. PDD was also related to longer disease duration and other NMS, such as anxiety, fatigue, dementia, REM sleep behavior disorder, and autonomic dysfunction.

CONCLUSION

We suggest that these markers may be used for distinguishing isolated depression from that related to neurodegeneration, especially in individuals that concurrently present with other known prodromal symptoms of PD and other α-synucleinopathies. However, future prospective studies are warranted to confirm this hypothesis.

Neuroinflammation and Autophagy in Parkinson's Disease-Novel Perspectives

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder. It is characterized by the accumulation of α-Synuclein aggregates and the degeneration of dopaminergic neurons in substantia nigra in the midbrain. Although the exact mechanisms of neuronal degeneration in PD remain largely elusive, various pathogenic factors, such as α-Synuclein cytotoxicity, mitochondrial dysfunction, oxidative stress, and pro-inflammatory factors, may significantly impair normal neuronal function and promote apoptosis. In this context, neuroinflammation and autophagy have emerged as crucial processes in PD that contribute to neuronal loss and disease development. They are regulated in a complex interconnected manner involving most of the known PD-associated genes. This review summarizes evidence of the implication of neuroinflammation and autophagy in PD and delineates the role of inflammatory factors and autophagy-related proteins in this complex condition. It also illustrates the particular significance of plasma and serum immune markers in PD and their potential to provide a personalized approach to diagnosis and treatment.

Pathogenesis of α-Synuclein in Parkinson's Disease: From a Neuron-Glia Crosstalk Perspective

Parkinson's disease (PD) is a progressive neurodegenerative disorder. The classical behavioral defects of PD patients involve motor symptoms such as bradykinesia, tremor, and rigidity, as well as non-motor symptoms such as anosmia, depression, and cognitive impairment. Pathologically, the progressive loss of dopaminergic (DA) neurons in the substantia nigra (SN) and the accumulation of α-synuclein (α-syn)-composed Lewy bodies (LBs) and Lewy neurites (LNs) are key hallmarks. Glia are more than mere bystanders that simply support neurons, they actively contribute to almost every aspect of neuronal development and function; glial dysregulation has been implicated in a series of neurodegenerative diseases including PD. Importantly, amounting evidence has added glial activation and neuroinflammation as new features of PD onset and progression. Thus, gaining a better understanding of glia, especially neuron-glia crosstalk, will not only provide insight into brain physiology events but also advance our knowledge of PD pathologies. This review addresses the current understanding of α-syn pathogenesis in PD, with a focus on neuron-glia crosstalk. Particularly, the transmission of α-syn between neurons and glia, α-syn-induced glial activation, and feedbacks of glial activation on DA neuron degeneration are thoroughly discussed. In addition, α-syn aggregation, iron deposition, and glial activation in regulating DA neuron ferroptosis in PD are covered. Lastly, we summarize the preclinical and clinical therapies, especially targeting glia, in PD treatments.

A Focus on Astrocyte Contribution to Parkinson's Disease Etiology

Parkinson's disease (PD) is an incurable neurodegenerative disease of high prevalence, characterized by the prominent death of dopaminergic neurons in the substantia nigra pars compacta, which produces dopamine deficiency, leading to classic motor symptoms. Although PD has traditionally been considered as a neuronal cell autonomous pathology, in which the damage of vulnerable neurons is responsible for the disease, growing evidence strongly suggests that astrocytes might have an active role in the neurodegeneration observed. In the present review, we discuss several studies evidencing astrocyte implications in PD, highlighting the consequences of both the loss of normal homeostatic functions and the gain in toxic functions for the wellbeing of dopaminergic neurons. The revised information provides significant evidence that allows astrocytes to be positioned as crucial players in PD etiology, a factor that needs to be taken into account when considering therapeutic targets for the treatment of the disease.

Inflammation and immune dysfunction in Parkinson disease

Parkinson disease (PD) is a progressive neurodegenerative disease that affects peripheral organs as well as the central nervous system and involves a fundamental role of neuroinflammation in its pathophysiology. Neurohistological and neuroimaging studies support the presence of ongoing and end-stage neuroinflammatory processes in PD. Moreover, numerous studies of peripheral blood and cerebrospinal fluid from patients with PD suggest alterations in markers of inflammation and immune cell populations that could initiate or exacerbate neuroinflammation and perpetuate the neurodegenerative process. A number of disease genes and risk factors have been identified as modulators of immune function in PD and evidence is mounting for a role of viral or bacterial exposure, pesticides and alterations in gut microbiota in disease pathogenesis. This has led to the hypothesis that complex gene-by-environment interactions combine with an ageing immune system to create the 'perfect storm' that enables the development and progression of PD. We discuss the evidence for this hypothesis and opportunities to harness the emerging immunological knowledge from patients with PD to create better preclinical models with the long-term goal of enabling earlier identification of at-risk individuals to prevent, delay and more effectively treat the disease.

Perception of Physical Demand, Mental Demand, and Performance: A Comparison of Two Voice Interventions for Parkinson's Disease

PURPOSE

The purpose of the study was to examine the effect of two voice intervention approaches for hypophonia secondary to Parkinson's disease (PD) on self-reported measures of physical demand, mental demand, and vocal performance.

METHOD

Thirty-four persons with hypophonia secondary to PD were assigned to one of three groups: Lee Silverman Voice Treatment (LSVT) LOUD (n = 12), SpeechVive (n = 12), and nontreatment clinical control (n = 10). The LSVT LOUD and the SpeechVive participants received 8 weeks of voice intervention following the standardized protocol previously described for each approach. To confirm the effectiveness of each voice intervention, sound pressure level (dB SPL) data were analyzed for the experimental and control participants for a monologue sample obtained pretreatment, midtreatment, and posttreatment. During the voice intervention period, the LSVT LOUD and the SpeechVive participants were instructed to complete a modified version of the National Aeronautics and Space Administration Task Load Index rating scale to indicate the mental and physical demand required to complete the intervention activities, and to indicate how well they performed in completing the assigned vocal tasks.

RESULTS

The LSVT LOUD and the SpeechVive participants demonstrated a significant posttreatment increase in SPL (dB), in comparison to the clinical controls, thus confirming a positive intervention effect. The LSVT LOUD participants reported significantly higher ratings of physical and mental demand over the course of treatment, in comparison to the SpeechVive participants.

CONCLUSION

Consideration of the mental and physical demand associated with two voice intervention approaches, commonly used for PD, may help to foster improved therapeutic compliance and treatment outcomes.

Blood-based biomarker in Parkinson's disease: potential for future applications in clinical research and practice

The clinical presentation of Parkinson's disease (PD) is both complex and heterogeneous, and its precise classification often requires an intensive work-up. The differential diagnosis, assessment of disease progression, evaluation of therapeutic responses, or identification of PD subtypes frequently remains uncertain from a clinical point of view. Various tissue- and fluid-based biomarkers are currently being investigated to improve the description of PD. From a clinician's perspective, signatures from blood that are relatively easy to obtain would have great potential for use in clinical practice if they fulfill the necessary requirements as PD biomarker. In this review article, we summarize the knowledge on blood-based PD biomarkers and present both a researcher's and a clinician's perspective on recent developments and potential future applications.

Perception of Swallowing-Related Fatigue Among Older Adults

PURPOSE

Although fatigue is recognized as clinically relevant to swallowing performance, its prevalence and significance in dysphagic and nondysphagic adults have not been sufficiently examined. In this study, an online survey was used to examine swallowing- and eating-related fatigue (SERF) symptoms, the relationship between perceived SERF and other dysphagia-related health outcomes, and whether perceived SERF predicts risk for dysphagia or malnutrition.

METHOD

An online survey of older adults (aged 60 years or older) was conducted. A novel 12-item scale was developed to capture perceived SERF. Previously validated scales were used to measure dysphagia risk, sarcopenia, general fatigue, malnutrition risk, and quality of life. Logistic regression was used to examine whether SERF predicted risk for dysphagia and/or malnutrition.

RESULTS

Complete responses were collected from 417 community-dwelling adults (M _age = 70.6 years, SD = 4.9; 263 women); 75% (n = 312) reported at least some degree of SERF. SERF was significantly correlated with dysphagia risk, sarcopenia, general fatigue, malnutrition risk, and quality of life. SERF was a significant predictor of dysphagia risk while controlling for age, gender, and other health outcomes (odds ratio [OR] = 1.2, 95% confidence interval [CI; 1.16, 1.27], p < .001). For every unit increase in SERF score, the odds of being at risk for dysphagia were associated with an increase of 22%. Significant predictors for malnutrition risk included SERF (OR = 0.94, 95% CI [0.91, 0.98]), general fatigue (OR = 0.95, 95% CI [0.92, 0.99]), and quality of life (OR = 1.04, 95% CI [1.0, 1.1]).

CONCLUSIONS

Fatigue during swallowing and mealtimes is experienced by community-dwelling older adults and predicted dysphagia risk and malnutrition risk. Further research is needed to refine and validate a patient-reported outcome measure for SERF and examine the effects of fatigue on swallowing function and physiology under imaging.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.20405835.

Emerging urinary alpha-synuclein and miRNA biomarkers in Parkinson's disease

Parkinson's disease (PD) is one of the most common neurodegenerative diseases after Alzheimer's disease (AD), afflicting adults above the age of sixty irrespective of gender, race, ethnicity, and social status. PD is characterized by motor dysfunctions, displaying resting tremor, rigidity, bradykinesia, and postural imbalance. Non-motor symptoms, including rapid eye movement (REM) behavior disorder, constipation, and loss of sense of smell, typically occur many years before the appearance of the PD motor symptoms that lead to a diagnosis. The loss of dopaminergic neurons in the substantia nigra, which leads to the motor symptoms seen in PD, is associated with the deposition of aggregated, misfolded α-Synuclein (α-Syn, SNCA) proteins forming Lewy Bodies. Additionally, dysregulation of miRNA (a short form of mRNA) may contribute to the developing pathophysiology in PD and other diseases such as cancer. Overexpression of α-Syn and miRNA in human samples has been found in PD, AD, and dementia. Therefore, evaluating these molecules in urine, present either in the free form or in association with extracellular vesicles of biological fluids, may lead to early biomarkers for clinical diagnosis. Collection of urine is non-invasive and thus beneficial, particularly in geriatric populations, for biomarker analysis. Considering the expression and function of α-Syn and miRNA, we predict that they can be used as early biomarkers in the diagnosis and prognosis of neurodegenerative diseases.

Exploration of the Common Gene Characteristics and Molecular Mechanism of Parkinson's Disease and Crohn's Disease from Transcriptome Data

Parkinson's disease (PD) is the second most common neurodegenerative disorder, and the mechanism of its occurrence is still not fully elucidated. Accumulating evidence has suggested that the gut acts as a potential origin of PD pathogenesis. Recent studies have identified that inflammatory bowel disease acts as a risk factor for Parkinson's disease, although the underlying mechanisms remain elusive. The aim of this study was to further explore the molecular mechanism between PD and Crohn's disease (CD). The gene expression profiles of PD (GSE6613) and CD (GSE119600) were downloaded from the Gene Expression Omnibus (GEO) database and were identified as the common differentially expressed genes (DEGs) between the two diseases. Next, analyses were performed, including functional enrichment analysis, a protein-protein interaction network, core genes identification, and clinical correlation analysis. As a result, 178 common DEGs (113 upregulated genes and 65 downregulated genes) were found between PD and CD. The functional analysis found that they were enriched in regulated exocytosis, immune response, and lipid binding. Twelve essential hub genes including BUB1B, BUB3, DLGAP5, AURKC, CBL, PCNA, RAF1, LYN, RPL39L, MRPL13, RSL24D1, and MRPS11 were identified from the PPI network by using cytoHubba. In addition, inflammatory and metabolic pathways were jointly involved in these two diseases. After verifying expression levels in an independent dataset (GSE99039), a correlation analysis with clinical features showed that LYN and RAF1 genes were associated with the severity of PD. In conclusion, our study revealed the common pathogenesis of PD and CD. These common pathways and hub genes may provide novel insights for mechanism research.

Depression in Patients with Parkinson's Disease: Current Understanding of its Neurobiology and Implications for Treatment

Depression is one of the most frequent and burdensome non-motor symptoms in Parkinson’s disease (PD), across all stages. Even when its severity is mild, PD depression has a great impact on quality of life for these patients and their caregivers. Accordingly, accurate diagnosis, supported by validated scales, identification of risk factors, and recognition of motor and non-motor symptoms comorbid to depression are critical to understanding the neurobiology of depression, which in turn determines the effectiveness of dopaminergic drugs, antidepressants and non-pharmacological interventions. Recent advances using in vivo functional and structural imaging demonstrate that PD depression is underpinned by dysfunction of limbic networks and monoaminergic systems, depending on the stage of PD and its associated symptoms, including apathy, anxiety, rapid eye movement sleep behavior disorder (RBD), cognitive impairment and dementia. In particular, the evolution of serotonergic, noradrenergic, and dopaminergic dysfunction and abnormalities of limbic circuits across time, involving the anterior cingulate and orbitofrontal cortices, amygdala, thalamus and ventral striatum, help to delineate the variable expression of depression in patients with prodromal, early and advanced PD. Evidence is accumulating to support the use of dual serotonin and noradrenaline reuptake inhibitors (desipramine, nortriptyline, venlafaxine) in patients with PD and moderate to severe depression, while selective serotonin reuptake inhibitors, repetitive transcranial magnetic stimulation and cognitive behavioral therapy may also be considered. In all patients, recent findings advocate that optimization of dopamine replacement therapy and evaluation of deep brain stimulation of the subthalamic nucleus to improve motor symptoms represents an important first step, in addition to physical activity. Overall, this review indicates that increasing understanding of neurobiological changes help to implement a roadmap of tailored interventions for patients with PD and depression, depending on the stage and comorbid symptoms underlying PD subtypes and their prognosis.

Serum Inflammatory Markers and Progression of Nonmotor Symptoms in Early Parkinson's Disease

BACKGROUND

The influence of peripheral inflammation on nonmotor symptoms (NMSs) in Parkinson's disease (PD) remains unclear.

OBJECTIVE

The aim of this study was to explore whether serum inflammatory marker profiles are associated with the progression of NMSs in early PD.

METHODS

We included 45 patients with early PD and 20 healthy control subjects. Six inflammatory markers, including interleukin (IL)-1β, IL-2, IL-6, IL-10, tumor necrosis factor-α, and high-sensitivity C-reactive protein, were measured. NMSs were assessed using the Non-Motor Symptoms Scale, Montreal Cognitive Assessment, and Composite Autonomic Symptom Score-31 at baseline and after 3 years.

RESULTS

Principal component (PC) analysis showed that only PC3 scores, mainly loaded by IL-2 and IL-6, were significantly elevated in the PD group compared with the control group. Higher PC3 scores in the PD group were associated with faster progression of Non-Motor Symptoms Scale total and mood/apathy domain scores. There were no significant associations of PC scores with Montreal Cognitive Assessment and Composite Autonomic Symptom Score-31 score changes.

CONCLUSIONS

Peripheral inflammation may be related to the evolution of NMSs, particularly mood symptoms, in the early stages of PD. © 2022 International Parkinson and Movement Disorder Society.

Peripheral inflammatory cytokines and motor symptoms in persons with Parkinson's disease

Background

Many of the motor symptoms of Parkinson's disease (PD) impact quality of life and are not fully ameliorated by current pharmacological and surgical treatments. A better understanding of the pathophysiology underlying these symptoms is needed. Previous research has suggested that inflammation may play a significant role in PD pathophysiology and progression, but there is limited research exploring how inflammation directly relates to motor symptoms in PD. Thus, the purpose of this study was to evaluate associations between peripheral immune inflammatory markers and motor symptoms of PD, specifically, tremor, bradykinesia, and postural and gait instability. We hypothesized that peripheral inflammatory cytokines would predict the severity of motor symptoms in persons with PD, and that there will be higher levels of peripheral inflammatory cytokine markers in persons with PD when compared to age-matched healthy older adults.

Methods

Twenty-six participants with PD and fourteen healthy older adults completed the study. For participants with PD, the motor section of the Unified Parkinson's Disease Rating Scale (UPDRS) was recorded and scored by two Movement Disorders Neurologists masked to the study. A blood sample was collected from both participants with PD and the healthy older adults. Through the MILLIPLEX® map High Sensitivity Human Cytokine Kit, key inflammation-related markers were analyzed (TNF-α, IFN-γ, IL-1β, IL-8, IL-2, IL-7, IL-5, IL-13, IL, 4, IL-10 IL-12p70, GM-CSF, and IL-6).

Results

Results revealed significantly higher levels of IL-6 in persons with PD when compared to healthy older adults (p ​= ​0.005). Moreover, results revealed that higher levels of IL-4 (p ​= ​0.011) and lower levels of IFNγ (p ​= ​0.003) significantly predicted more severe tremor in persons with PD. No other associations between the peripheral inflammation markers and other motor symptoms were observed.

Conclusions

Overall, these results are consistent with a growing body of literature that implicates inflammatory cytokines in the PD, and further suggests that inflammatory cytokines, or lack thereof, may be associated with tremor in persons with PD.

Chinese Herbal Medicine in the Treatment of Depression in Parkinson’s Disease: From Molecules to Systems

Depression is one of the most common non-motor symptoms in patients with Parkinson’s disease (PD). Depression in PD (DPD) increases the disability rate and reduces the quality of life of PD patients and increases the caregiver burden. Although previous studies have explained the relationship between depression and PD through a variety of pathological mechanisms, whether depression is a precursor or an independent risk factor for PD remains unclear. Additionally, increasing evidence shows that conventional anti-PD drug therapy is not ideal for DPD. Chinese Herbal Medicine (CHM) prescriptions exhibit the characteristics of multi-target, multi-pathway, and multi-level treatment of DPD and may simultaneously improve the motor symptoms of PD patients through multiple mechanisms. However, the specific pharmacological mechanisms of these CHM prescriptions remain unelucidated. Here, we investigated the mechanisms of action of the active ingredients of single herbs predominantly used in CHM prescriptions for depression as well as the therapeutic effect of CHM prescriptions on DPD. This review may facilitate the design of new selective and effective treatment strategies for DPD.

Biomarker of Neuroinflammation in Parkinson's Disease

Parkinson's disease (PD) is caused by abnormal accumulation of α-synuclein in dopaminergic neurons of the substantia nigra, which subsequently causes motor symptoms. Neuroinflammation plays a vital role in the pathogenesis of neurodegeneration in PD. This neuroinflammatory neurodegeneration involves the activation of microglia, upregulation of proinflammatory factors, and gut microbiota. In this review, we summarized the recent findings on detection of PD by using inflammatory biomarkers, such as interleukin (IL)-1β, IL-2, IL-6, IL-10, tumor necrosis factor (TNF)-α; regulated upon activation, normal T cell expressed and presumably secreted (RANTES) and high-sensitivity c-reactive protein (hsCRP); and radiotracers such as [11C]PK11195 and [18F]-FEPPA, as well as by monitoring disease progression and the treatment response. Many PD-causing mutations in SNCA, LRRK2, PRKN, PINK1, and DJ-1 are also associated with neuroinflammation. Several anti-inflammatory medications, including nonsteroidal anti-inflammatory drugs (NSAID), inhibitors of TNF-α and NLR family pyrin domain containing 3 (NLRP3), agonists of nuclear factor erythroid 2-related factor 2 (NRF2), peroxisome proliferator-activated receptor gamma (PPAR-γ), and steroids, have demonstrated neuroprotective effects in in vivo or in vitro PD models. Clinical trials applying objective biomarkers are required to investigate the therapeutic potential of anti-inflammatory medications for PD.

Dietary Patterns and Nonmotor Symptoms in Parkinson's Disease: A Cross-Sectional Analysis

OBJECTIVE

Evidence-based treatment for nonmotor symptoms in Parkinson's disease (PD) is limited. Lifestyle-based improvements including dietary changes may be a potential management strategy. The intent of this research was to investigate the extent to which 3 dietary indices (Mediterranean-DASH Diet Intervention for Neurodegenerative Delay [MIND], Dietary Inflammation Index [DII], and Healthy Diet Indicator [HDI-2020]) are associated with overall and individual nonmotor symptom severity among individuals with PD.

METHOD

An exploratory cross-sectional analysis of dietary (food frequency questionnaire) and clinical data was undertaken, including measures of overall nonmotor symptom severity, such as fatigue, depression, anxiety, apathy, sleep problems, daytime sleepiness, and cognitive impairment. The relationship between each dietary score and symptom outcome was assessed by linear regression for continuous variables and through general linear model analysis for tertiles of dietary adherence.

RESULTS

None of the dietary indices significantly predicted the total nonmotor symptom severity score. The HDI predicted a significant decrease in fatigue scores as measured by the NeuroQoL fatigue item (standardized β = -.19, p = 0.022), after adjusting for age, sex, energy intake, years since diagnosis, physical activity level, education, and smoking. Self-reported depression symptoms reduced by .17 (standardized β) for each unit increase in HDI score (p = 0.035), after controlling for age, gender, energy intake, and years since diagnosis. No other significant associations were evident between dietary scores and any other nonmotor symptoms.

CONCLUSIONS

Our results indicate that fatigue and depression in PD may be modified by diet; however, more research is needed using a larger sample to replicate these findings.

Supplemental data for this article is available online at https://doi.org/10.1080/07315724.2022.2056544 .

Effects of the COVID-19 Pandemic on Parkinson's Disease: a Single-Centered Qualitative Study

BACKGROUND

The public health measure restrictions across the world due to COVID-19 have inadvertently impacted the routines for people with Parkinson's disease (PD) and their care partners not only in terms of compromised neurological clinical care but also drastically changing the way of life to minimize the risk of becoming infected. This study explores initial PD patients' lived experiences to observe how quality of life and health care has been affected at the start of the COVID-19 pandemic and provide insight into the importance of patient engagement and virtual care.

METHODS

Twenty-two virtual, in-depth semi-structured interviews with persons diagnosed with PD who usually attend a Movement Disorders specialty clinic in Calgary, Alberta, were completed between April 28 and May 13, 2020, and the care partners that wished to participate. Interviews were recorded and transcribed, after which transcripts were analyzed and coded into relevant themes using NVivo 12.

RESULTS

Impacts from the public health measures and COVID-19 results into three main themes: (1) Impacts of COVID-19 on PD Clinical Care; (2) Activities of Daily Living; (3) Attitudes and Perceptions. Participants reported worsening in motor and nonmotor symptoms and had to accommodate to clinical care via virtual means which were associated with limitations and suggestions for improvement of remote care.

CONCLUSION

This study provides a unique opportunity for researchers to better understand the lived experiences of PD patients in all aspects of their life suggesting that innovative means are needed for facilitating virtual health care medicine and increased social interaction.

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.

Role of exosomes in the pathogenesis of inflammation in Parkinson's disease

Inflammatory responses, including glial cell activation and peripheral immune cell infiltration, are involved in the pathogenesis of Parkinson’s disease (PD). These inflammatory responses appear to be closely related to the release of extracellular vesicles, such as exosomes. However, the relationships among different forms of glial cell activation, synuclein dysregulation, mitochondrial dysfunction, and exosomes are complicated. This review discusses the multiple roles played by exosomes in PD-associated inflammation and concludes that exosomes can transport toxic α-synuclein oligomers to immature neurons and into the extracellular environment, inducing the oligomerization of α-synuclein in normal neurons. Misfolded α-synuclein causes microglia and astrocytes to activate and secrete exosomes. Glial cell-derived exosomes participate in communications between glial cells and neurons, triggering anti-stress and anti-inflammatory responses, in addition to axon growth. The production and release of mitochondrial vesicles and exosomes establish a new mechanism for linking mitochondrial dysfunction to systemic inflammation associated with PD. Given the relevance of exosomes as mediators of neuron-glia communication in neuroinflammation and neuropathogenesis, new targeted treatment strategies are currently being developed that use these types of extracellular vesicles as drug carriers. Exosome-mediated inflammation may be a promising target for intervention in PD patients.