Autonomic dysfunction in Parkinson's disease: a comprehensive symptom survey

Complement C1q-dependent engulfment of alpha-synuclein induces ENS-resident macrophage exhaustion and accelerates Parkinson's-like gut pathology

Deposition of misfolded α-synuclein (αsyn) in the enteric nervous system (ENS) is found in multiple neurodegenerative diseases. It is hypothesized that ENS synucleinopathy contributes to both the pathogenesis and non-motor morbidity in Parkinson's Disease (PD), but the cellular and molecular mechanisms that shape enteric histopathology and dysfunction are poorly understood. Here, we demonstrate that ENS-resident macrophages, which play a critical role in maintaining ENS homeostasis, initially respond to enteric neuronal αsyn pathology by upregulating machinery for complement-mediated engulfment. Pharmacologic depletion of ENS-macrophages or genetic deletion of C1q enhanced enteric neuropathology. Conversely, C1q deletion ameliorated gut dysfunction, indicating that complement partially mediates αsyn-induced gut dysfunction. Internalization of αsyn led to increased endo-lysosomal stress that resulted in macrophage exhaustion and temporally correlated with the progression of ENS pathology. These novel findings highlight the importance of enteric neuron-macrophage interactions in removing toxic protein aggregates that putatively shape the earliest stages of PD in the periphery.

Role of cardiac β1-adrenergic and A1-adenosine receptors in severe arrhythmias related to Parkinson's disease

AIMS

Although reduced life expectancy in Parkinson's Disease (PD) patients has been related to severe cardiac arrhythmias due to autonomic dysfunctions, its molecular mechanisms remain unclear. To investigate the role of cardiac β1-Adrenergic (β1AR) and A1-Adenosine (A1R) receptors in these dysfunctions, the pharmacological effects of stimulation of cardiac β1AR (isoproterenol, ISO), in the absence and presence of cardiac β1AR (atenolol, AT) or A1R (1,3-dipropyl-8-cyclopentyl xanthine, DPCPX) blockade, on the arrhythmias induced by Ischemia/Reperfusion (CIR) in an animal PD model were studied.

METHODS

PD was produced by dopaminergic lesions (confirmed by immunohistochemistry analysis) caused by the injection of 6-hydroxydopamine (6-OHDA, 6 μg) in rat striatum. CIR was produced by a surgical interruption for 10 min followed by reestablishment of blood circulation in the descendent left coronary artery. On the incidence of CIR-Induced Ventricular Arrhythmias (VA), Atrioventricular Block (AVB), and Lethality (LET), evaluated by Electrocardiogram (ECG) analysis, the effects of intravenous treatment with ISO, AT and DPCPX (before CIR) were studied.

RESULTS

VA, AVB and LET incidences were significantly higher in 6-OHDA (83%, 92%, 100%, respectively) than in control rats (58%, 67% and 67%, respectively). ISO treatment significantly reduced these incidences in 6-OHDA (33%, 33% and 42%, respectively) and control rats (25%, 25%, 33%, respectively), indicating that stimulation of cardiac β1AR induced cardioprotection. This response was prevented by pretreatment with AT and DPCPX, confirming the involvement of cardiac β1AR and A1R.

CONCLUSION

Pharmacological modulation of cardiac β1AR and A1R could be a potential therapeutic strategy to reduce severe arrhythmias and increase life expectancy in PD patients.

Parkinson's Disease and Diabetes Mellitus: Synergistic Effects on Pathophysiology and GI Motility

PURPOSE OF REVIEW

Parkinson's disease and diabetes affect an increasing proportion of the aging global population. Both conditions extensively affect gastrointestinal (GI) motility with similar and differing clinical symptoms. Nonetheless, GI symptoms in Parkinson's disease and diabetes pose significant morbidity and impairment of quality of life. Their pathophysiology is poorly understood, and therefore, effective treatment options are lacking.

RECENT FINDINGS

Parkinson's disease patients have oropharyngeal dysphagia and constipation. They also have mild or absent upper GI symptoms associated with delayed gastric emptying, which is prevalent in 70% of patients. Delayed gastric emptying in Parkinson's disease leads to erratic medication absorption and fluctuating motor symptoms. Half of diabetics have upper GI symptoms, which correlate to gastric emptying and changes in brain activity of the insular cortex. The majority of diabetics also have constipation. Diabetics have an increased risk for developing Parkinson's disease and anti-diabetic medications are associated with risk reduction of developing Parkinson's disease. Hyperglycemia is associated with advanced glycated end products formation and acceleration of α-synuclein aggregation. GLP-1 receptor agonists have also demonstrated efficacy in improving motor symptoms and cognition in Parkinson's disease patients with diabetes. Parkinson's disease and diabetes are pan-enteric disorders with significant GI symptoms and impairment of gut motility. Both conditions have synergistic pathophysiologies that propagate neurodegenerative changes. Treatment options for GI symptoms in diabetic and Parkinson's disease patients are lacking. Anti-diabetic treatment improves motor symptoms in Parkinson's disease, however, its effect on GI symptoms is unclear.

Prevalence and Factors Associated with Drooling in Parkinson’s Disease: Results from a Longitudinal Prospective Cohort and Comparison with a Control Group

Introduction. Drooling in Parkinson’s disease (PD) is frequent but often goes underrecognized. Our aim was to examine the prevalence of drooling in a PD cohort and compare it with a control group. Specifically, we identified factors associated with drooling and conducted subanalyses in a subgroup of very early PD patients. Patients and Methods. PD patients who were recruited from January 2016 to November 2017 (baseline visit; V0) and evaluated again at a 2-year ± 30-day follow-up (V2) from 35 centers in Spain from the COPPADIS cohort were included in this longitudinal prospective study. Subjects were classified as with or without drooling according to item 19 of the NMSS (Nonmotor Symptoms Scale) at V0, V1 (1-year ± 15 days), and V2 for patients and at V0 and V2 for controls. Results. The frequency of drooling in PD patients was 40.1% (277/691) at V0 (2.4% (5/201) in controls; $p$  < 0.0001), 43.7% (264/604) at V1, and 48.2% (242/502) at V2 (3.2% (4/124) in controls; $p$  < 0.0001), with a period prevalence of 63.6% (306/481). Being older (OR = 1.032; $p$  = 0.012), being male (OR = 2.333; $p$  < 0.0001), having greater nonmotor symptom (NMS) burden at the baseline (NMSS total score at V0; OR = 1.020; $p$  < 0.0001), and having a greater increase in the NMS burden from V0 to V2 (change in the NMSS total score from V0 to V2; OR = 1.012; $p$  < 0.0001) were identified as independent predictors of drooling after the 2-year follow-up. Similar results were observed in the group of patients with ≤2 years since symptom onset, with a cumulative prevalence of 64.6% and a higher score on the UPDRS-III at V0 (OR = 1.121; $p$  = 0.007) as a predictor of drooling at V2. Conclusion. Drooling is frequent in PD patients even at the initial onset of the disease and is associated with a greater motor severity and NMS burden.

Challenges in the clinical advancement of cell therapies for Parkinson's disease

Cell therapies as potential treatments for Parkinson's disease first gained traction in the 1980s, owing to the clinical success of trials that used transplants of foetal midbrain dopaminergic tissue. However, the poor standardization of the tissue for grafting, and constraints on its availability and ethical use, have hindered this treatment strategy. Recent advances in stem-cell technologies and in the understanding of the development of dopaminergic neurons have enabled preclinical advancements of promising stem-cell therapies. To move these therapies to the clinic, appropriate levels of safety screening, as well as optimization of the cell products and the scalability of their manufacturing, will be required. In this Review, we discuss how challenges pertaining to cell sources, functional and safety testing, manufacturing and storage, and clinical-trial design are being addressed to advance the translational and clinical development of cell therapies for Parkinson's disease.

Salivation in Parkinson's disease: A scoping review

OBJECTIVES

We aimed to provide an overview of the available literature that includes both objective assessments (namely hypersalivation and hyposalivation) and the subjective experience (namely xerostomia and drooling) of salivary problems in patients with Parkinson's disease.

BACKGROUND

In patients with Parkinson's disease, there may be complaints of salivary problems such as xerostomia or drooling. This can have consequences for their oral health and quality of life. To date, systematic reviews have focused on drooling only.

MATERIALS AND METHODS

A literature search in 4 databases was performed up to 12 February 2021. Two researchers independently assessed studies for eligibility.

RESULTS

In total, 63 studies were included. The prevalence of self-reported xerostomia ranged from 49% to 77%, and that of self-reported drooling ranged from 5% to 80%. Ten articles reported a significantly lower mean salivary flow in patients with Parkinson's disease than in controls. None of the articles with both a control group and a patient group reported a significantly higher salivary flow in patients with Parkinson's disease. When questioned about subjective salivary problems, a significantly higher prevalence of both xerostomia (7 studies) and drooling (14 studies) was found in patients with Parkinson's disease than in controls. Patients with Parkinson's disease have a lower salivary flow rate and higher prevalence of both xerostomia and drooling than controls.

CONCLUSION

The complexity of salivary problems present in patients with Parkinson's disease necessitates a multidisciplinary approach in order to avoid mutually counteracting treatments from different healthcare professionals.

Motor and non-motor features in Parkinson's Disease patients carrying GBA gene mutations

BACKGROUND

Mutations of the Glucocerebrosidase (GBA) gene are the most common genetic risk factor yet discovered for Parkinson's Disease (PD), being found in about 5-14% of Caucasian patients.

OBJECTIVE

We aimed to assess motor and non-motor symptoms (NMS) in patients with GBA-related PD (GBA-PD) in comparison with idiopathic PD (iPD) subjects using standardized and validated scales.

METHODS

Eleven (4 M, 7 F) patients with GBA-PD and 22 iPD patients, selected from the same cohort and matched for gender, age, and disease duration, were enrolled. The disease severity was assessed by Unified Parkinson's Disease Rating Scale-section III, gait disorder and falls by Freezing of Gait Questionnaire, and motor fluctuations by Wearing off questionnaire. NMS were evaluated using the following scales: Mini-Mental State Examination and extended neuropsychological battery, if required, Non-Motor Symptoms Scale, SCOPA-AUT Questionnaire, Apathy Evaluation Scale, Beck Depression Inventory, Epworth Sleepiness Scale, Restless Legs Syndrome Rating Scale, REM Sleep Behavior Disorder Screening Questionnaire, and Questionnaire for Impulsive-Compulsive Disorders in Parkinson's disease.

RESULTS

GBA-PD patients showed a more severe and rapidly progressive disease, and more frequent positive family history for PD, akinetic-rigid phenotype, postural instability, dementia, and psychosis in comparison to iPD. Two of three subjects carrying L444P mutation presented with early dementia. We also found a higher occurrence of fatigue, diurnal sleepiness, and intolerance to heat/cold in the carriers group.

CONCLUSIONS

Our results confirm that NMS and a more severe and faster disease course more frequently occur among GBA-PD patients in comparison to iPD.

Autonomic failure: Clinicopathologic, physiologic, and genetic aspects

Over the past century, generations of neuroscientists, pathologists, and clinicians have elucidated the underlying causes of autonomic failure found in neurodegenerative, inherited, and antibody-mediated autoimmune disorders, each with pathognomonic clinicopathologic features. Autonomic failure affects central autonomic nervous system components in the α-synucleinopathy, multiple system atrophy, characterized clinically by levodopa-unresponsive parkinsonism or cerebellar ataxia, and pathologically by argyrophilic glial cytoplasmic inclusions (GCIs). Two other central neurodegenerative disorders, pure autonomic failure characterized clinically by deficits in norepinephrine synthesis and release from peripheral sympathetic nerve terminals; and Parkinson's disease, with early and widespread autonomic deficits independent of the loss of striatal dopamine terminals, both express Lewy pathology. The rare congenital disorder, hereditary sensory, and autonomic neuropathy type III (or Riley-Day, familial dysautonomia) causes life-threatening autonomic failure due to a genetic mutation that results in loss of functioning baroreceptors, effectively separating afferent mechanosensing neurons from the brain. Autoimmune autonomic ganglionopathy caused by autoantibodies targeting ganglionic α3-acetylcholine receptors instead presents with subacute isolated autonomic failure affecting sympathetic, parasympathetic, and enteric nervous system function in various combinations. This chapter is an overview of these major autonomic disorders with an emphasis on their historical background, neuropathological features, etiopathogenesis, diagnosis, and treatment.

Gut microbiome and Parkinson's disease: Perspective on pathogenesis and treatment

BACKGROUND

Parkinson's disease (PD) is a disease of ⍺-synuclein aggregation-mediated dopaminergic neuronal loss in the substantia nigra pars compacta, which leads to motor and non-motor symptoms. Through the last two decades of research, there has been growing consensus that inflammation-mediated oxidative stress, mitochondrial dysfunction, and cytokine-induced toxicity are mainly involved in neuronal damage and loss associated with PD. However, it remains unclear how these mechanisms relate to sporadic PD, a more common form of PD. Both enteric and central nervous systems have been implicated in the pathogenesis of sporadic PD, thus highlighting the crosstalk between the gut and brain.

AIM

of Review: In this review, we summarize how alterations in the gut microbiome can affect PD pathogenesis. We highlight various mechanisms increasing/decreasing the risk of PD development. Based on the previous supporting evidence, we suggest how early interventions could protect against PD development and how controlling specific factors, including our diet, could modify our perspective on disease mechanisms and therapeutics. We explain the strong relationship between the gut microbiota and the brain in PD subjects, by delineating the multiple mechanisms involved inneuroinflammation and oxidative stress. We conclude that the neurodetrimental effects of western diet (WD) and the neuroprotective effects of Mediterranean diets should be further exploredin humans through clinical trials. Key Scientific Concepts of Review: Alterations in the gut microbiome and associated metabolites may contribute to pathogenesis in PD. In some studies, probiotics have been shown to exert anti-oxidative effects in PD via improved mitochondrial dynamics and homeostasis, thus reducing PD-related consequences. However, there is a significant unmet need for randomized clinical trials to investigate the effectiveness of microbial products, probiotic-based supplementation, and dietary intervention in reversing gut microbial dysbiosis in PD.

The prevalence and associated factors of dysphagia in Parkinson's disease: A systematic review and meta-analysis

Background

The prevalence and associated factors of dysphagia in Parkinson's disease (PD) are different in studies conducted in different countries. The purpose of our systematic review and meta-analysis was to evaluate the prevalence of dysphagia in PD and to clarify its associated factors.

Methods

Two researchers systematically searched PubMed, Embase, Web of Science, Cochrane Library, CNKI, Wanfang Database, SinoMed and VIP databases and manually searched references in the retrieved articles to identify potential research subjects. The last search was conducted on June 28, 2022. Finally, a total of 58 studies including 60 observations with 20,530 PD patients were included in our meta-analysis.

Results

The meta-analysis estimated that the pooled prevalence rate of dysphagia in PD was 36.9% (95% CI: 30.7–43.6%) and instrumental examination showed a higher prevalence (57.3%, 95% CI: 44.3–69.1%). Oceania showed the highest prevalence of dysphagia in PD (56.3%) compared to Africa (39.5%), Asia (38.6%), Europe (36.1%) and America (28.9%). Dysphagia in PD was associated with older age, lower body mass index, longer disease duration, higher Hoehn and Yahr stage and levodopa equivalent daily dose, PIGD subtype, severe motor symptoms, drooling and higher levels of depression, and lower quality of life.

Conclusions

In conclusion, our meta-analysis showed that dysphagia occurs in more than one-third of PD patients and was associated with several demographic characteristics and PD-related characteristics, motor symptoms, non-motor symptoms, as well as decreased quality of life. It deserves early screening, diagnosis, and treatment in clinical practice to prevent serious complications from dysphagia.

Neuroinflammation and Parkinson's Disease-From Neurodegeneration to Therapeutic Opportunities

Parkinson’s disease (PD) is the second most prevalent neurodegenerative disorder worldwide. Clinically, it is characterized by a progressive degeneration of dopaminergic neurons (DAn), resulting in severe motor complications. Preclinical and clinical studies have indicated that neuroinflammation can play a role in PD pathophysiology, being associated with its onset and progression. Nevertheless, several key points concerning the neuroinflammatory process in PD remain to be answered. Bearing this in mind, in the present review, we cover the impact of neuroinflammation on PD by exploring the role of inflammatory cells (i.e., microglia and astrocytes) and the interconnections between the brain and the peripheral system. Furthermore, we discuss both the innate and adaptive immune responses regarding PD pathology and explore the gut–brain axis communication and its influence on the progression of the disease.

Assessment of myocardial sympathetic innervation with 18F-FDOPA-PET/CT in patients with autonomic dysfunction: feasibility study in IPD patients

BACKGROUND

Dysfunction and denervation of myocardial nor-adrenergic sympathetic neurons has been documented in IPD patients with dysautonomia. The aim of this study was to evaluate the feasibility of single tracer imaging of myocardial sympathetic and cerebral striatal involvement in these patients.

METHODS

Twenty-two controls (mean-age 59.09 ± 12.39 years, 15 men) with no clinical autonomic-dysfunction and normal striatal-uptake in 18F-FDOPA-PET/CT; and 28 patients (mean-age 58.18 ± 8.25 years, 18 men) with autonomic-dysfunction (in Autonomic Function Tests) and striatal dopaminergic-dysfunction were enrolled. Both cardiac-PET/CT (40 minutes post IV-injection of 185-259MBq 18F-FDOPA) and Brain-PET/CT (60 minutes post-IV) were acquired in same session. ROIs were drawn over the entire left ventricular myocardium, individual walls and mediastinum for quantification. Patients and controls were followed-up for 26.93 ± 5.43 months and 37.91 ± 8.63 months, respectively.

RESULTS

Striatal and myocardial-parameters were significantly lower in patients compared to controls; with Myocardium/mediastinal ratio (MwMR) yielding the area-under-the-curve of .941 (P < .001). MwMR correlated negatively with the drop in systolic blood pressure (SBP) during AFTs {Pearson-coefficient (-).565, P = .002}. Mean MwMR in patients with abnormal-AFTs was significantly lower than patients with borderline-AFTs (1.39 ± .12 vs 1.55 ± .10; P = .002). 9/20 patients with abnormal-AFTs showed functional worsening during follow-up, compared to 2/8 with borderline-AFTs.

CONCLUSION

Single tracer, single session imaging of striatal and cardiac sympathetic dysfunction in patients with advanced IPD is feasible with use of 18F-FDOPA. Significantly reduced 18F-FDOPA uptake is seen in the myocardium of the IPD patients with sympathetic dysfunction.

Gastric Emptying Is Not Delayed and Does Not Correlate With Attenuated Postprandial Blood Flow Increase in Medicated Patients With Early Parkinson's Disease

Background

We have recently used phase-contrast magnetic resonance imaging (PC-MRI) to demonstrate an attenuated postprandial blood flow response in the superior mesenteric artery (SMA) in 23 medicated patients with Parkinson's disease (PD) compared to 23 age- and sex-matched healthy controls.

Objective

To investigate in a sub-sample of the original cohort whether the observed blood flow response in SMA after oral food intake is related to a delay in gastric emptying.

Methods

We studied 15 patients with PD in an “ON-medication” state with a mean disease duration of 3.9 ± 2.2 years and 15 healthy age- and sex-matched individuals. Participants underwent dynamic gastric scintigraphy 0, 30, 60, 120, 180 and 240 minutes after the intake of a standardized radiolabeled test meal. Gastric emptying was compared between groups. 14 of the 15 PD patients and 12 of the 15 healthy control subjects had previously undergone serial postprandial PC-MRI measurements. In these individuals, we tested for a relationship between gastric emptying and postprandial blood flow response in the SMA.

Results

The dynamics of gastric emptying did not differ between groups (p = 0.68). There was substantial inter-subject variability of gastric emptying in PD patients and healthy participants. Only a single PD patient had delayed gastric emptying. In those participants who had undergone PC-MRI, postprandial increase in SMA blood flow was attenuated in PD compared to healthy controls as reported previously (p = 0.006). Gastric emptying did not correlate with the timing and amplitude of postprandial blood flow increase in SMA.

Conclusion

Our preliminary results, obtained in a small group of early-stage PD patients who continued their usual dopamine replacement therapy, suggest that variations in gastric emptying after solid meal intake is within the normal range in the majority of cases. There is also no evidence for a tight relationship between the attenuated postprandial blood flow response in the SMA and normal variations in gastric emptying.

Constitutive nuclear accumulation of endogenous alpha-synuclein in mice causes motor impairment and cortical dysfunction, independent of protein aggregation

A growing body of evidence suggests that nuclear alpha-synuclein (αSyn) plays a role in the pathogenesis of Parkinson’s disease (PD). However, this question has been difficult to address as controlling the localization of αSyn in experimental systems often requires protein overexpression, which affects its aggregation propensity. To overcome this, we engineered Snca^NLS mice, which localize endogenous αSyn to the nucleus. We characterized these mice on a behavioral, histological and biochemical level to determine whether the increase of nuclear αSyn is sufficient to elicit PD-like phenotypes. Snca^NLS mice exhibit age-dependent motor deficits and altered gastrointestinal function. We found that these phenotypes were not linked to αSyn aggregation or phosphorylation. Through histological analyses, we observed motor cortex atrophy in the absence of midbrain dopaminergic neurodegeneration. We sampled cortical proteomes of Snca^NLS mice and controls to determine the molecular underpinnings of these pathologies. Interestingly, we found several dysregulated proteins involved in dopaminergic signaling, including Darpp32, Pde10a and Gng7, which we further confirmed was decreased in cortical samples of the Snca^NLS mice compared with controls. These results suggest that chronic endogenous nuclear αSyn can elicit toxic phenotypes in mice, independent of its aggregation. This model raises key questions related to the mechanism of αSyn toxicity in PD and provides a new model to study an underappreciated aspect of PD pathogenesis.

Gastrointestinal Dysfunction in Parkinson’s Disease: Current and Potential Therapeutics

Abnormalities in the gastrointestinal (GI) tract of Parkinson’s disease (PD) sufferers were first reported over 200 years ago; however, the extent and role of GI dysfunction in PD disease progression is still unknown. GI dysfunctions, including dysphagia, gastroparesis, and constipation, are amongst the most prevalent non-motor symptoms in PD. These symptoms not only impact patient quality of life, but also complicate disease management. Conventional treatment pathways for GI dysfunctions (i.e., constipation), such as increasing fibre and fluid intake, and the use of over-the-counter laxatives, are generally ineffective in PD patients, and approved compounds such as guanylate cyclase C agonists and selective 5-hyroxytryptamine 4 receptor agonists have demonstrated limited efficacy. Thus, identification of potential targets for novel therapies to alleviate PD-induced GI dysfunctions are essential to improve clinical outcomes and quality of life in people with PD. Unlike the central nervous system (CNS), where PD pathology and the mechanisms involved in CNS damage are relatively well characterised, the effect of PD at the cellular and tissue level in the enteric nervous system (ENS) remains unclear, making it difficult to alleviate or reverse GI symptoms. However, the resurgence of interest in understanding how the GI tract is involved in various disease states, such as PD, has resulted in the identification of novel therapeutic avenues. This review focuses on common PD-related GI symptoms, and summarizes the current treatments available and their limitations. We propose that by targeting the intestinal barrier, ENS, and/or the gut microbiome, may prove successful in alleviating PD-related GI symptoms, and discuss emerging therapies and potential drugs that could be repurposed to target these areas.

Autonomic and Depression Symptoms in Parkinson's Disease: Clinical Evidence for Overlapping Physiology

BACKGROUND

Autonomic dysfunction and depression are common non-motor symptoms of Parkinson's disease (PD) that confer poorer prognosis. These PD symptoms may have overlapping pathophysiologic underpinnings.

OBJECTIVE

To investigate associations between autonomic and depression symptoms in early PD, and their evolution over time.

METHODS

We obtained data from the Parkinson's Progression Markers Initiative, a prospective open-access database of early PD. Regression analyses were used to model effects of depression on autonomic symptoms in controls and in PD at baseline, visit 6 (24 months after baseline), and visit 12 (60 months after baseline), correcting for multiple comparisons.

RESULTS

Data from 421 people with PD at baseline, 360 at visit 6, 300 at visit 12, and 193 controls were included. When controlling for age, depression, and anti-hypertensive medications, depression predicted autonomic symptoms in all groups. Accounting for motor symptoms did not alter these associations. When comparing groups, the influence of depression on autonomic symptoms was stronger in all PD groups compared to controls, and strongest in PD at visit 12. Depression predicted the presence of orthostatic hypotension only in the PD group at visit 12.

CONCLUSION

We demonstrated the important impact of depression on autonomic symptoms in early and middle stages of PD, which are independent of motor symptoms. Though the physiologic basis of these two PD symptoms are not fully understood, our findings add to pathologic evidence of a shared mechanistic substrate, separate from that responsible for PD motor symptoms. These findings may influence clinical management and development of novel therapies.

Is activation of GDNF/RET signaling the answer for successful treatment of Parkinson's disease? A discussion of data from the culture dish to the clinic

The neurotrophic signaling of glial cell line-derived neurotrophic factor (GDNF) with its canonical receptor, the receptor tyrosine kinase RET, coupled together with the GDNF family receptor alpha 1 is important for dopaminergic neuron survival and physiology in cell culture experiments and animal models. This prompted the idea to try GDNF/RET signaling as a therapeutic approach to treat Parkinson's disease with the hallmark of dopaminergic cell death in the substantia nigra of the midbrain. Despite several clinical trials with GDNF in Parkinson's disease patients, which mainly focused on optimizing the GDNF delivery technique, benefits were only seen in a few patients. In general, the endpoints did not show significant improvements. This suggests that it will be helpful to learn more about the basic biology of this fascinating but complicated GDNF/RET signaling system in the dopaminergic midbrain and about recent developments in the field to facilitate its use in the clinic. Here we will refer to the latest publications and point out important open questions in the field.

[Thermoregulatory dysfunction in Parkinson's disease]

Thermoregulatory dysfunction is considered to be the least investigated among all the autonomic disorders in Parkinson disease. Pathophysiological mechanisms of this phenomena involve as central, as peripheric parts of nervous system. Dopamine deficiency in combination with peripheric autonomic dysfunction leads to temperature balance disturbance, which may be expressed by various clinical symptoms. Dopaminergic innervation of preoptic-anterior hypothalamus area plays a crucial role in thermoregulation function of central nervous system. Current thermoregulatory tests give possibility not only to reveal sudomotor and heat dissipation disorders in patients with Parkinson disease, but also to make differential diagnosis with other neurodegenerative disorders. Early detection and treatment of thermoregulatory dysfunction may improve quality of life in patients with Parkinson disease.

Gastroparesis in Parkinson Disease: Pathophysiology, and Clinical Management

Patients with Parkinson disease (PD) experience a range of non-motor symptoms, including gastrointestinal symptoms. These symptoms can be present in the prodromal phase of the disease. Recent advances in pathophysiology reveal that α-synuclein aggregates that form Lewy bodies and neurites, the hallmark of PD, are present in the enteric nervous system and may precede motor symptoms. Gastroparesis is one of the gastrointestinal involvements of PD and is characterized by delayed gastric emptying of solid food in the absence of mechanical obstruction. Gastroparesis has been reported in nearly 45% of PD. The cardinal symptoms include early satiety, postprandial fullness, nausea, and vomiting. The diagnosis requires an appropriate test to confirm delayed gastric emptying, such as gastric scintigraphy, or breath test. Gastroparesis can lead to malnutrition and impairment of quality of life. Moreover, it might interfere with the absorption of antiparkinsonian drugs. The treatment includes dietary modifications, and pharmacologic agents both to accelerate gastric emptying and relieve symptoms. Alternative treatments have been recently developed in the management of gastroparesis, and their use in patients with PD will be reported in this review.

Vagus Nerve and Stomach Synucleinopathy in Parkinson's Disease, Incidental Lewy Body Disease, and Normal Elderly Subjects: Evidence Against the "Body-First" Hypothesis

BACKGROUND

Braak and others have proposed that Lewy-type α-synucleinopathy in Parkinson's disease (PD) may arise from an exogenous pathogen that passes across the gastric mucosa and then is retrogradely transported up the vagus nerve to the medulla.

OBJECTIVE

We tested this hypothesis by immunohistochemically staining, with a method specific for p-serine 129 α-synuclein (pSyn), stomach and vagus nerve tissue from an autopsy series of 111 normal elderly subjects, 33 with incidental Lewy body disease (ILBD) and 53 with PD.

METHODS

Vagus nerve samples were taken adjacent to the carotid artery in the neck. Stomach samples were taken from the gastric body, midway along the greater curvature. Formalin-fixed paraffin-embedded sections were immunohistochemically stained for pSyn, shown to be highly specific and sensitive for α-synuclein pathology.

RESULTS

Median disease duration for the PD group was 13 years. In the vagus nerve none of the 111 normal subjects had pSyn in the vagus, while 12/26 ILBD (46%) and 32/36 PD (89%) subjects were pSyn-positive. In the stomach none of the 102 normal subjects had pSyn while 5/30 (17%) ILBD and 42/52 (81%) of PD subjects were pSyn-positive.

CONCLUSION

As there was no pSyn in the vagus nerve or stomach of subjects without brain pSyn, these results support initiation of pSyn in the brain. The presence of pSyn in the vagus nerve and stomach of a subset of ILBD cases indicates that synucleinopathy within the peripheral nervous system may occur, within a subset of individuals, at preclinical stages of Lewy body disease.

Sudomotor and cardiovascular autonomic function in de novo Parkinson's disease assessed by sudoscan and cardiovascular reflexes

OBJECTIVE

The prevalence of autonomic involvement in early stage of Parkinson 's disease (PD) is still debated. Aim of this study is to assess the autonomic functions in de novo PD patients (dnPD) in comparison with PD patients on therapy (PDot) and healthy controls (HC).

METHODS

Twenty-eight dnPD and 24 PDot, to whom Unified Parkinson's Rating Scale (UPDRS) was administered, and 23 HC underwent electrochemical skin conductance (ESC) measured with sudoscan, cardiovascular reflexes (head-up tilt test HUTT, Valsalva maneuver, deep breathing, hand grip, and cold face),and Scales for Outcomes in Parkinson's Disease-Autonomic Dysfunction (SCOPA-AUT) questionnaire.

RESULTS

The mean SCOPA-AUT total score was significantly higher in dnPD group compared with HC group (p < 0.001) and significantly lower than PDot (p = 0.004). No significant difference of ESC mean values were found between dnPD and HC group. DnPD had a significantly lower diastolic blood pressure (BP) response at handgrip test (p = 0.005) compared with HC. Hands and feet ESC significantly negatively correlated with disease duration (p = 0.014; p = 0.025) and feet ESC significantly negatively correlated with UPDRS III (p = 0.039). Systolic and diastolic BP responses at 3rd minute of HUTT correlated significantly negatively with disease duration (p < 0.001; p = 0.003) and with UPDRSIII (p = 0.001; p < 0.001). BP response to Valsalva maneuver negatively correlated with UPDRSIII (p = 0.006).

CONCLUSION

Although dnPD patients complain of thermoregulatory symptoms, we found no alteration in the sudomotor function investigated with sudoscan. Furthermore, a deficit of the sympathetic vasoconstrictive response to the isometric exercise was detected, suggesting an early involvement of the autonomic cardiovascular components in dnPD.

Association of autonomic symptoms with cerebrospinal fluid biomarkers in Parkinson disease and scans without evidence of dopaminergic deficit

Dysautonomia is common in patients with Parkinson disease (PD) since disease early phase. Scales for Outcomes in Parkinson's disease - Autonomic (SCOPA-AUT) is a well-designed scale assessing the autonomic dysfunctions of PD patients. Our objectives were to examine the autonomic dysfunction in PD and scan without evidence of dopaminergic deficit (SWEDD) patients and to assess the correlation of autonomic dysfunctions with cerebrospinal fluid (CSF) biomarkers.An analysis of the Parkinson's Progression Markers Initiative (PPMI) data including 414 PD patients, 60 SWEDD patients, and 170 healthy controls (HCs) with baseline CSF biomarker measurements and SCOPA-AUT assessments was presented. Autonomic symptoms including gastrointestinal, urinary, cardiovascular, pupillomotor, thermoregulatory and sexual dysfunctions were assessed by SCOPA-AUT scales. Spearman correlation test was used to examine the correlations between CSF measurements and each section of SCOPA-AUT scales in HCs and subjects with PD or SWEDD.More severe autonomic dysfunctions were observed in patients with SWEDD than those with PD (P < .001). Specifically, patients with PD have lower scores on the urinary scale [4 (0-17) vs 5 (1-18)], pupillomotor scale [0 (0-3) vs 0 (0-3)], thermoregulatory scale [0 (0-4) vs 1.5 (0-10)] and sexual scale [1 (0-6) vs 2 (0-6)] compared with SWEDD patients. Thermoregulatory dysfunction scores were found correlated with CSF α-syn levels in SWEDD group, and gastrointestinal dysfunction scores were correlated with CSF Abeta1-42 in PD group. Additionally, urinary dysfunction scores were correlated with CSF total tau and tau phosphorylated at threonine 181(p-tau181) levels in both HCs and PD patients.

Autonomic Dysfunctions in Parkinson's Disease: Prevalence, Clinical Characteristics, Potential Diagnostic Markers, and Treatment

Parkinson's disease (PD) is a common neurodegenerative disease in the middle-aged and the elderly. Symptoms of autonomic dysfunctions are frequently seen in PD patients, severely affecting the quality of life. This review summarizes the epidemiology, clinical manifestations, and treatment options of autonomic dysfunctions. The clinical significance of autonomic dysfunctions in PD early diagnosis and differential diagnosis is also discussed.

Characterization of Gastrointestinal Symptom Type and Severity in Parkinson's Disease: A Case-Control Study in an Australian Cohort

Background

While constipation is a well-known non-motor symptom which may precede the onset of the classical motor symptoms of PD, there have been few comprehensive studies of gastrointestinal (GI) symptoms in people with PD (PwP).

Objectives

To investigate the spectrum of GI symptoms in an Australian PwP cohort and their relationship to use of anti-parkinsonian medications dietary habits and smoking.

Methods

The prevalence and severity of GI symptoms were compared in a group of 163 PwP and 113 healthy control subjects using the Gastrointestinal Symptom Rating Scale (GSRS). Corrected linear regression models were used to determine differences between PwP and controls, and to investigate the influence of different classes of anti-Parkinsonian medications.

Results

PwP reported a greater frequency of constipation and GI-associated illnesses when compared to healthy controls. Total GSRS scores (P < 0.0001), upper GI symptoms (P < 0.0001), and hypoactive GI Symptoms (P < 0.0001) were all significantly greater in the PD cohort than controls. Further analyses revealed a positive association between the use of anti-Parkinsonian medications and total GSRS scores (P < 0.001), as well as upper GI symptoms (P < 0.001) and hypoactive GI function (P < 0.001).

Conclusions

This study illustrates the frequency and array of GI symptoms in a large PD cohort. The findings indicate that anti-parkinsonian medications play an important role in the presentation and development of GI symptoms.

Is Gut Dysbiosis an Epicenter of Parkinson's Disease?

Once recognized as one of the most esoteric diseases of the central nervous system, Parkinson's disease (PD) is now deemed to be a chronic illness contributed by the central, autonomic and enteric nervous systems. Most likely, an accumulation of α-synuclein in the central and enteric nervous systems is the key that supports this viewpoint. Constipation, one of the non-motor hallmarks in roughly two-third of PD patients, is regulated by the composition of gut bacteria, which is assumed to set off the enteric α-synuclein accrual. Vagus nerve is suggested to direct the signal for α-synuclein over-expression and accumulation to the brain. While trillions of microorganisms reside in the intestinal tract, only one third of the proportion inhabits evenly in all individuals. Existence of an impaired gut-microbe-brain axis consonant with dysbiosis could be an epicenter of this inexplicable disorder. Any alteration in the structure and function of the gastrointestinal tract owing to exposure of endogenous or exogenous chemicals or toxicants could lead to dysbiosis. However, inconsistency in the symptoms even after exposure to same chemical or toxicant in PD patients emphatically creates a conundrum. While the level of a few specific neurotransmitters and metabolites is influenced by microbes, implication of dysbiosis is still debatable. Nevertheless, the scientific literature is overflowing with the remarkable observations supporting the role of dysbiosis in PD. Lack of specificity to differentially diagnose PD with non-PD or PD-plus syndrome, to identify highly precise drug targets and to develop therapeutic stratagems to encounter the disease on the basis of this approach, causes us to be open-minded about the dysbiosis theory. The article reviews the facts supporting gut dysbiosis as the foremost trigger for PD onset along with disagreements.

Autonomic disorders in Parkinson disease: Disrupted hypothalamic connectivity as revealed from resting-state functional magnetic resonance imaging

Converging evidence from diverse methodologies implicate the hypothalamus in the pathophysiology of Parkinson's disease (PD). Pathology in the hypothalamus and in hypothalamic pathways has been linked primarily to autonomic dysfunction, routinely experienced by individuals with PD throughout the course of the disease, sometimes predating onset of motor symptoms. Postmortem and molecular imaging studies have delineated pathologic changes in the hypothalamus and demonstrated alterations in neurotransmitter systems within this structure and associated pathways, which track the progression of the disease. More recently, functional interactions between the hypothalamus, thalamus, and striatum, as assessed using resting-state functional magnetic resonance imaging, were shown to be reduced in PD patients with high in comparison to those with low autonomic symptom burden. These functional changes may relate to micro- and macrostructural alterations which are also observed in PD. An examination of the hypothalamus and hypothalamic pathways can also shed light on atypical parkinsonian disorders and their distinct pathophysiologic characteristics relative to idiopathic PD. Altogether, the current state of knowledge on the involvement of the hypothalamus in PD is profound, yet emerging methodological advances are likely to move our understanding of hypothalamic pathology in PD significantly forward.

Fatal autonomic failure due to premanifesting Parkinson's disease only diagnosed at autopsy

A 46-year-old male had 11-year history of cryptic autonomic dysfunction. He developed a fatal autonomic failure with diffuse hypoxic brain injury. Histology examination of medulla oblongata and the celiac ganglion revealed many α-synuclein immunoreactive Lewy bodies confirming the diagnosis of premanifesting Parkinson's disease (PD). PNS involvement in PD is underappreciated.

Autonomic Dysfunction in Parkinson's Disease

Recognition of the importance of nonmotor dysfunction as a component of Parkinson's disease has exploded over the past three decades. Autonomic dysfunction is a frequent and particularly important nonmotor feature because of the broad clinical spectrum it covers. Cardiovascular, gastrointestinal, urinary, sexual, and thermoregulatory abnormalities all can appear in the setting of Parkinson's disease. Cardiovascular dysfunction is characterized most prominently by orthostatic hypotension. Gastrointestinal dysfunction can involve virtually all levels of the gastrointestinal tract. Urinary dysfunction can entail either too frequent voiding or difficulty voiding. Sexual dysfunction is frequent and frustrating for both patient and partner. Alterations in sweating and body temperature are not widely recognized but often are present. Autonomic dysfunction can significantly and deleteriously impact quality of life for individuals with Parkinson's disease. Because effective treatment for many aspects of autonomic dysfunction is available, it is vitally important that assessment of autonomic dysfunction be a regular component of the neurologic history and exam and that appropriate treatment be initiated and maintained.

Pharmacokinetics, Safety, and Tolerability of Orally Administered Ursodeoxycholic Acid in Patients With Parkinson's Disease-A Pilot Study

Mitochondrial dysfunction is implicated in the pathogenesis of Parkinson's disease. Preliminary data have shown lower brain adenosine triphosphate (ATP) levels in Parkinson's disease versus age-matched healthy controls. Ursodeoxycholic acid (UDCA) may improve impaired mitochondrial function. Our objective was to evaluate UDCA tolerability, pharmacokinetics, and its effect on brain bioenergetics in individuals with Parkinson's disease. An open-label, prospective, multiple-ascending-dose study of oral UDCA in 5 individuals with Parkinson's disease was completed. A blood safety panel, plasma concentrations of UDCA and UDCA conjugates, and brain ATP levels were measured before and after therapy (week 1: 15 mg/kg/day; week 2: 30 mg/kg/day; and weeks 3-6: 50 mg/kg/day). UDCA and conjugates were measured using liquid chromatography-mass spectrometry. ATP levels and ATPase activity were measured using 7-Tesla 31 P magnetic resonance spectroscopy. Secondary measures included the Unified Parkinson's Disease Rating Scale and Montreal Cognitive Assessment. UDCA was generally well tolerated. The most frequent adverse event was gastrointestinal discomfort, rated by subjects as mild to moderate. Noncompartmental pharmacokinetic analysis resulted in (mean ± standard deviation) a maximum concentration of 8749 ± 2840 ng/mL and half-life of 2.1 ± 0.71 hr. Magnetic resonance spectroscopy data were obtained in 3 individuals with Parkinson's disease and showed modest increases in ATP and decreases in ATPase activity. Changes in Unified Parkinson's Disease Rating Scale (parts I-IV) and Montreal Cognitive Assessment scores (mean ± standard deviation) were -4.6 ± 6.4 and 2 ± 1.7, respectively. This is the first report of UDCA use in individuals with Parkinson's disease. Its pharmacokinetics are variable, and at high doses it appears reasonably well tolerated. Our findings warrant additional studies of its effect on brain bioenergetics.

Methods for detecting toxic α-synuclein species as a biomarker for Parkinson's disease

Parkinson's disease (PD) is the most common neurodegenerative movement disorder and is characterized by the accumulation of α-synuclein (α-syn) into insoluble aggregates known as Lewy bodies and Lewy neurites in the brain. However, prior to the formation of these large aggregates, α-syn forms oligomers and small fibrils, which are believed to be the pathogenic species leading to the death of neurons in the substantia nigra in disease. The majority of aggregated α-syn is phosphorylated, and it is thought that this post-translational modification may be critical in disease pathogenesis. Thus, early detection of the toxic forms of α-syn may provide a window of opportunity for an intervention to halt or slow the progression of neurodegeneration in PD. Expression of α-syn is not restricted to the central nervous system and the protein can be found elsewhere, including bodily fluids and peripheral tissues. This review will examine current methods for detecting toxic forms of α-syn in accessible biospecimens and outline emerging techniques that may provide reliable identification of biomarkers for PD.

Modification of the gut microbiome to combat neurodegeneration

The gut microbiome was extensively researched for its biological variety and its potential role in propagating diseases outside of the gastrointestinal (GI) tract. Recently, a lot of effort was focused on comprehending the gut-brain axis and the bizarre communication between the GI system and the nervous system. Ample amount of studies being carried out also revealed the involvement of the gut microbiome in enhancing the degree of many neurological disorders, including neurodegenerative diseases. It was widely observed that there were distinct microbiome profiles and dysbiosis within patients suffering from Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis. Various approaches to re-establish the balance of the gut microbiome, from antibiotic therapy, fecal microbiota transplant, or ingestion of psychobiotics, are discussed within this review within the specific context of combating neurodegenerative diseases. Present studies and clinical trials indicate that although there is an immense potential of gut microbiome modification to be preventive or therapeutic, there are still many intercalated components of the gut-brain axis at play and thus, more research needs to be carried out to delineate microbiome factors that may potentially alleviate symptoms of neurodegeneration.

Cardiovascular alterations in rats with Parkinsonism induced by 6-OHDA and treated with Domperidone

After Alzheimer, Parkinson disease (PD) is the most frequently occurring progressive, degenerative neurological disease. It affects both sympathetic and parasympathetic nervous systems in a variable fashion. Cardiovascular symptoms are present in almost all stages of PD and narrower heart rate variability is the earliest sign. Administration of Levodopa to PD patients has proven to provide some degree of neurological protection. This drug, however, causes side effects including nausea and vomiting, lessened by the administration of domperidone. Autopsies in PD patients led some researchers to suggest the involvement of the ventricular arrhythmia induced by domperidone. The aim of the present study was to determine the impact of the adjusted human maximal dose of domperidone, on cardiological features of Wistar rats. domperidone was administered to both 6-hydroxydopamine Parkinsonism models and regular Wistar rats. Quantitative analysis of ranges of heart beat variation showed significant abnormal distribution in both groups receiving domperidone as compared with respective sham counterparts. However, qualitative analysis of Poincaré plots showed that 6-hydroxydopamine Parkinsonism models receiving domperidone had the narrowest full range of heart beat and the worst distribution heart beat ranges as compared with all study groups corroborating with previous suggestion that domperidone administration to PD patients is likely to play a role in sudden unexpected death in this group of patients.

Inflammatory Bowel Diseases and Parkinson's Disease

The etiology of Parkinson's disease (PD) is multifactorial, with genetics, aging, and environmental agents all a part of the PD pathogenesis. Widespread aggregation of the α-synuclein protein in the form of Lewy bodies and Lewy neurites, and degeneration of substantia nigra dopamine neurons are the pathological hallmarks of PD. Inflammatory responses manifested by glial reactions, T cell infiltration, and increased expression of inflammatory cytokines, as well as other toxic mediators derived from activated glial cells, are currently recognized as prominent features of PD. Experimental, clinical and epidemiological data suggest that intestinal inflammation contributes to the pathogenesis of PD, and the increasing number of studies suggests that the condition may start in the gastrointestinal system years before any motor symptoms develop. Patients with inflammatory bowel disease (IBD) have a higher risk of developing PD compared with non-IBD individuals. Gene association study has found a genetic link between IBD and PD, and an evidence from animal studies suggests that gut inflammation, similar to that observed in IBD, may induce loss of dopaminergic neurons. Based on preclinical models of PD, it is suggested that the enteric microbiome changes early in PD, and gut infections trigger α-synuclein release and aggregation. In this paper, the possible link between IBD and PD is reviewed based on the available literature. Given the potentially critical role of gastrointestinal pathology in PD pathogenesis, there is reason to suspect that IBD or its treatments may impact PD risk. Thus, clinicians should be aware of PD symptoms in IBD patients.

Clinical Rating Scales for Urinary Symptoms in Parkinson Disease: Critique and Recommendations

Background

The prevalence of lower urinary tract symptoms (LUTS) is high in Parkinson's disease (PD). These problems negatively affect quality of life and include both storage and voiding problems. The International Parkinson and Movement Disorder Society established a task force to review clinical rating scales/questionnaires for the assessment of urinary symptoms in PD.

Methods

According to prespecified criteria, these scales/questionnaires were classified as "Recommended" or "Recommended with caveats" when clinimetric properties were satisfactory for Recommended status but had not been assessed specifically in PD, "Suggested" or "Listed." These assessments were applied to rate scales as screening tools for the diagnosis of LUTS and for the rating of symptom severity.

Results

Among scales that included LUTS but focused on overall autonomic or non-motor symptoms in PD, no scale reached the clinimetric rigor to be designated as Recommended or Recommended with caveats, but some were Suggested for either diagnostic screening tools or severity measures. Among primary urological scales, most are well validated in urological setting, but none was validated specifically in PD. DAN-PSS (Danish PSS), ICIQ (International Consultation for Incontinence Questionnaire)-MLUTS (Male Lower Urinary Tract Symptoms), OABq, OABq-SF (ICIQ-OABqol), OAB-V8 (as screening tool), and OABSS (OAB Symptom Score) met criteria for Recommended with caveats.

Conclusion

The Task Force does not recommend the development of a new scale. However, all above-mentioned questionnaires need to be studied further and specifically validated in PD.

Parkinson's Disease and Current Treatments for Its Gastrointestinal Neurogastromotility Effects

PURPOSE OF REVIEW

Gastrointestinal disturbances are seen in nearly all patients with Parkinson's disease and lead to impaired quality of life, affect drug pharmacodynamics, and potentially worsen patient's existing motor fluctuations, leading to further disability. Recent evidence links abnormal accumulations of α-synuclein aggregates in the periphery (gut) as seen in the cortex which causes dysfunctions impacting every level of the gastrointestinal tract from the esophagus, to the stomach, small bowel, colon, and rectum and can even predate the onset of the central neurologic disorder itself. Many treatments exist for the clinical phenotypes that result from the autonomic dysfunction and neuropathy involved in this neurodegenerative disorder. The treatments for the gut dysfunction seen in Parkinson's disease (PD) depend on the specific area of the gastrointestinal tract affected. For dysphagia, behavioral therapies with speech pathology, neuromuscular electrical stimulation, or botulinum toxin injection may be helpful. For gastroparesis, domperidone may serve as an antiemetic while also blunting the hypotensive potential of Levodopa while new treatments such as ghrelin agonists may prove beneficial to help appetite, satiety, gastric emptying in those with constipation, and even improve constipation. Antibiotics such as rifaximin with poor systemic absorption may be used to treat small bacterial overgrowth also found in those with PD while the benefits of probiotics is yet to be determined. Finally, constipation in PD can be a reflection of pelvic floor dyssynergia, slow transit constipation, or both, thus treatments targeting the specific anorectal dysfunction is necessary for better outcomes.

Management of constipation in patients with Parkinson's disease

A considerable body of research has recently emerged around nonmotor symptoms in Parkinson's disease (PD) and their substantial impact on patients' well-being. A prominent example is constipation which occurs in up to two thirds of all PD-patients thereby effecting psychological and social distress and consequently reducing quality of life. Despite the significant clinical relevance of constipation, unfortunately little knowledge exists on effective treatments. Therefore this systematic review aims at providing a synopsis on clinical effects and safety of available treatment options for constipation in PD. For this purpose, three electronic databases (MEDLINE, EMBASE, PsycINFO) were searched for experimental and quasi-experimental studies investigating the efficacy/effectiveness of interventions in the management of PD-associated constipation. Besides, adverse events were analyzed as secondary outcome. In total, 18 publications were identified involving 15 different interventions, of which none can be attributed sufficient evidence to derive strong recommendations. Nevertheless, some evidence indicates that dietetic interventions with probiotics and prebiotics may reduce symptom burden while providing a very favorable side-effects profile. Furthermore, the use of lubiprostone, macrogol and in the specific case of isolated or prominent outlet obstruction constipation injections of botulinum neurotoxin A into the puborectal muscles may as well be moderately supported. In summary, too little attention has been paid to treatment options for constipation in PD leaving abundant room for further research addressing this topic.

Constipation in Parkinson's Disease: a Nuisance or Nuanced Answer to the Pathophysiological Puzzle?

PURPOSE OF REVIEW

Chronic constipation is a common, nonmotor, and prodromal symptom in Parkinson's disease (PD). Its underlying neuropathology may provide pathophysiological insight into PD. Here, we critically review what is currently known about the neuroanatomical and brain-gut interactions, and the origin and progression of Lewy pathology (LP) at three levels-brain/brainstem, spinal cord, and enteric nervous system.

RECENT FINDINGS

Many recent studies have illustrated the challenges of examining LP in tissues obtained from colon biopsies of PD patients. Large-scale epidemiological studies have not confirmed the widely accepted Braakpostula. In this review, we propose an alternative origin and route of spread of LP in PD. We describe novel, noninvasive neurophysiological testing that could advance the understanding of LP and complex bidirectional brain-pelvic floor neural pathways in PD-a true disease model of a neurogastrointestinal disorder. This review may provide the impetus for future studies investigating gut and brain interaction and constipation in PD.

Critical Dysphagia is Common in Parkinson Disease and Occurs Even in Early Stages: A Prospective Cohort Study

To assess the prevalence of dysphagia and its typical findings in unselected "real-world" Parkinson patients using an objective gold-standard method. This was a prospective, controlled, cross-sectional study conducted in 119 consecutive Parkinson patients of all stages independent of subjective dysphagia. Patients and 32 controls were clinically and endoscopically examined by flexible endoscopic evaluation of swallowing (FEES) to evaluate the deglutition with regard to three consistencies (water, biscuit, and bread). Typical findings of dysphagia like penetration and aspiration, residues, and leakage were assessed. Dysphagia was common in Parkinson patients and occurred in all, even early, disease stages. Only 5% (6/119) of patients showed a completely unremarkable deglutition. Aspiration was seen in 25% (30/119) of patients and always related to water. Residues occurred in 93% (111/119), most commonly for bread. Leakage was much less frequent and was found in only 3-18%, depending on consistency. In a significant fraction of patients, objective dysphagia was not subjectively perceived. A total of 16% of asymptomatic patients suffered from critical aspiration. Significant swallowing deficiencies already occurred in early disease. Aspiration was found in 4 of 20 (20%) patients with disease duration of less than 2 years. Seven of 57 patients (12%) with Hoehn and Yahr stage 2 suffered from severe aspiration. Given the high frequency of critical aspiration in Parkinson disease, these patients should be evaluated early for dysphagia to avoid complications and recommend an adequate therapy. FEES is a simple, cost efficient, minimally invasive method that is ideally suited for this purpose.

Evolution of Orofacial Symptoms and Disease Progression in Idiopathic Parkinson's Disease: Longitudinal Data from the Jönköping Parkinson Registry

BACKGROUND

Orofacial symptoms are common in Parkinson's disease (PD) both as initial manifestations and late markers of disease complications. We aimed to investigate the evolution of orofacial manifestations and their prognostic value throughout PD progression.

METHODS

Data was obtained from "Jönköping Parkinson Registry" database on routine care visits of 314 people with idiopathic PD in southern Sweden. Information on baseline symptomatology, orofacial features, UPDRS, and medications was recorded at baseline and during each follow-up visit within an average of 4.2 (range: 1-12) years.

RESULTS

Hypomimia, affected speech, drooling, and impaired swallowing were present in 37.3%/91.6%, 14.1%/65.5%, 11.7%/55.3%, and 10.2%/34.5% at baseline/follow-up, respectively. Male sex [OR = 2.4 (95% CI: 1.0-5.9)], UPDRS motor scores [OR = 1.2 (95% CI: 1.1-1.3)], dominant rigidity [OR = 5.2 (95% CI: 1.4-19.1)], and autonomic disturbance [OR = 3.4 (95% CI: 1.1-10.9)] were risk factors for drooling. Individuals with more severe orofacial burden at baseline had shorter median time to develop UPDRS-Part III > 28 [3rd tertile = 4.7 yr, 2nd tertile = 6.2 yr, and 1st tertile = 7.8 yr; p = 0.014].

CONCLUSIONS

Majority of people with PD manifest orofacial manifestations at either early or late stages of the disease. PD severity, symmetry of motor disturbances, and autonomic disorders correlate with orofacial symptoms. Individuals with more severe orofacial burden at baseline progressed faster to more advanced stages.

Assessments of plasma ghrelin levels in the early stages of parkinson's disease

BACKGROUND

Gastrointestinal symptoms are early events in Parkinson's disease (PD). The gastrointestinal hormone ghrelin was neuroprotective in the nigrostriatal dopamine system. The objective of this study was to assess ghrelin levels in the early stages of PD.

METHODS

Plasma was collected in the fasting state in 291 PD patients in stages 1-3 and 303 age- and sex-matched healthy controls. Additional samples were taken in the glucose response test to assess nutrition-related ghrelin levels in 20 PD patients and 20 healthy controls. The enzyme-linked immunosorbent assay was used to measure total and active plasma ghrelin levels.

RESULTS

We reported that total and active plasma ghrelin levels were decreased in PD, although there was no difference across progressive PD stages. Postprandial ghrelin suppression and preprandial peak responses were both attenuated in PD.

CONCLUSIONS

Plasma ghrelin levels were decreased in PD; however, this event might be irrelevant to PD progression. Ghrelin responses to meals were also impaired in PD. © 2017 International Parkinson and Movement Disorder Society.

Premotor symptoms and the risk of Parkinson's disease: A case-control study in Mexican population

OBJECTIVES

To assess the prevalence of pre-motor symptoms and estimate the risk for developing Parkinson's disease in Mexican population.

PATIENTS AND METHODS

A case-control study was carried out with consecutive subjects with Parkinson's disease from two different referral centers in Mexico. Gender- and age-matched controls were randomly selected from the participating hospitals. All subjects were assessed using a structured questionnaire for the assessment of pre-motor symptoms (hyposmia, depression, anxiety, constipation, and sleep disorders). Odds ratios (OR) were calculated using logistic regression analysis.

RESULTS

A total of 430 subjects with PD and 430 healthy subjects were included. Premotor symptoms prevalence was 77.7% (n=334) for the PD group, compared to 41.3% (n=178) in the control group (p<0.001). After logistic multivariate analysis, previous history of hyposmia (OR 2.02 [95% CI 1.33-3.06]), depression (OR 2.52 [95% CI 1.67-3.84]), anxiety (OR 4.37 [95% CI 2.73-6.98]) and sleep disorders (OR 2.03 [95% CI 1.41-2.93]) were independently associated with Parkinson's disease. Overall prediction success of the model was 81.2% for controls and 61.2% for subjects with PD.

CONCLUSION

All five premotor symptoms assessed were more commonly reported in PD subjects than healthy controls. The presence of non-motor symptoms yield a prediction success of 71.2% to discriminate between PD subjects and healthy controls.

Measurement of Nonmotor Symptoms in Clinical Practice

Nonmotor symptoms constitute a prominent part of Parkinson's disease manifestations. They are present since the first phases of the disease, increase their number and severity with disease progression, and importantly impact on patients' health and quality of life, caregivers' burden, and social resources. Research on Parkinson's disease has traditionally focused on the motor aspects of the disease, but an increasing interest in the nonmotor manifestations has risen in the past decade. The availability of assessment instruments for detecting and measuring these symptoms has allowed understanding of their importance and course over time, as well as estimation of therapeutic effects on them. In this chapter, a review of the basic characteristics of nonmotor symptom assessments used in clinical practice and research are presented.

The gut-brain axis: is intestinal inflammation a silent driver of Parkinson's disease pathogenesis?

The state of the intestinal environment can have profound effects on the activity of the central nervous system through the physiological contributions of the microbiota, regulation of intestinal barrier function, and altered activity of peripheral neurons. The common language employed for much of the gut-brain communication is the modulation of immune activity. Chronic proinflammatory immune activity is increasingly being recognized as a fundamental element of neurodegenerative disorders, and in Parkinson's disease, inflammation in the intestine appears particularly relevant in pathogenesis. We review the evidence that intestinal dysfunction is present in Parkinson's disease and that it may reflect the earliest manifestations of Parkinson's disease pathology, and we link these findings to dysregulated immune activity. Based on this, we present a model for Parkinson's disease pathogenesis in which the disorder originates in the intestine and progresses with inflammation as its underlying mechanism. More in-depth investigations into the physiological mechanisms underlying peripheral pre-motor symptoms in Parkinson's disease are expected to lead to the development of novel diagnostic and therapeutic measures that can slow or limit progression of the disease to more advanced stages involving debilitating motor and cognitive symptoms.