Non-motor features of Parkinson's disease: depression and dementia

High-frequency multimodal training with a focus on Tai Chi in people with Parkinson's disease: a pilot study

Background and objectives

Cognitive decline is an important and common complication in patients with Parkinson's disease (PD) since it significantly reduces the quality of life. A breakthrough in treating and preventing cognitive decline in PD remains to be achieved. This study aimed to evaluate the effectiveness of high-frequency and intensive multimodal training in improving motor and cognitive function.

Methods

Twenty-eight patients diagnosed with idiopathic PD completed a comprehensive neuropsychological test battery and were neurologically examined. The patients of the intervention group (n = 15) underwent 2 weekly sessions of Tai Chi therapy over 4 weeks and participated in an individually tailored training program consisting of two modules (smartphone-based speech training and cognitive training). A matched control group consisted of n = 13 patients with PD who received computer-assisted cognitive training. The data were analyzed with repeated-measures ANOVA.

Results

Four weeks of high-frequency training showed significant effects on verbal and figural episodic memory and visuospatial function in the intervention group. Compared to the control group, the cognitive performance of the intervention group improved significantly in visuospatial function and figural episodic memory. A significant improvement was also shown in the intervention group in the Tinetti Mobility Test and the Epworth Sleepiness Scale. The significant effects in the Tinetti mobility test remained after the 6 months follow-up. After the intervention, the patients reported high motivation and satisfaction with the multimodal training.

Conclusion

In patients with PD, a multimodal training program not only improves gait and stability but may also contribute to improving cognition.

Clinical trial registration

ClinicalTrials.gov Identifier: NCT04103255; https://register.clinicaltrials.gov/prs/app/action/LoginUser?ts=1&cx=-jg9qo4.

The critical role of gut-brain axis microbiome in mental disorders

The Gut-brain axis is a bidirectional neural and humoral signaling that plays an important role in mental disorders and intestinal health and connects them as well. Over the past decades, the gut microbiota has been explored as an important part of the gastrointestinal tract that plays a crucial role in the regulation of most functions of various human organs. The evidence shows several mediators such as short-chain fatty acids, peptides, and neurotransmitters that are produced by the gut may affect the brain's function directly or indirectly. Thus, dysregulation in this microbiome community can give rise to several diseases such as Parkinson's disease, depression, irritable bowel syndrome, and Alzheimer's disease. So, the interactions between the gut and the brain are significantly considered, and also it provides a prominent subject to investigate the causes of some diseases. In this article, we reviewed and focused on the role of the largest and most repetitive bacterial community and their relevance with some diseases that they have mentioned previously.

Polyphenolic Glycosides from the Fruits Extract of Lycium ruthenicum Murr and Their Monoamine Oxidase B Inhibitory and Neuroprotective Activities

The fruits ofLycium ruthenicum Murr have long been consumed as health food and used in folk medicine in China. Apart from the well-known polysaccharides, the active small molecular constituents in this fruit have not been fully studied. In this work, a systematic phytochemical study was carried out to investigate the small molecules and their potential health benefits. Nine new polyphenolic glycosides, lyciumserin A-I (1-9), together with 16 known compounds (10-25), were isolated and elucidated by high-resolution electrospray ionization mass spectrometry and comprehensive NMR analyses in combination with chemical hydrolysis. Compounds 1, 2, and 16 exhibited moderate inhibitory activity of monoamine oxidase B (MAO-B), while compounds 1 (50 μM) and 2 (100 μM) displayed significant neuroprotective effects (69.22 and 72.38% of cell viability, respectively) in the 6-hydroxydopamine-induced injury of the PC12 cell model (54.41%), comparable to the positive drug rasagiline (70.45%). The neuroprotective effect of 1 and 2 was further evidenced by the observation of the morphological change and fluorescein diacetate/propidium iodide staining. In addition, the levels of the major active compounds (1, 3, 5/6, and 16-18) vary from 21.5 to 892.3 μg/g. This is the first report on phenolic glycosides from the fruits ofL. ruthenicum Murr that possess both significant MAO-B inhibitory and neuroprotective effects, indicating the promising potential of the fruits for the development of health care products and even therapeutic agents for the treatment of Parkinson's disease and other neurodegenerative diseases.

Are We What We Eat? Impact of Diet on the Gut-Brain Axis in Parkinson's Disease

Parkinson’s disease is characterized by motor and non-motor symptoms, such as defects in the gut function, which may occur before the motor symptoms. To date, there are therapies that can improve these symptoms, but there is no cure to avoid the development or exacerbation of this disorder. Dysbiosis of gut microbiota could have a crucial role in the gut–brain axis, which is a bidirectional communication between the central nervous system and the enteric nervous system. Diet can affect the microbiota composition, impacting gut–brain axis functionality. Gut microbiome restoration through probiotics, prebiotics, synbiotics or other dietary means could have the potential to slow PD progression. In this review, we will discuss the influence of diet on the bidirectional communication between gut and brain, thus supporting the hypothesis that this disorder could begin in the gut. We also focus on how food-based therapies might then have an influence on PD and could ameliorate non-motor as well as motor symptoms.

The Two Faces of Exosomes in Parkinson's Disease: From Pathology to Therapy

Accumulating evidence suggests that exosomes play a key role in Parkinson's disease (PD). Exosomes may contribute to the PD progression facilitating the spread of pathological alpha-synuclein or activating immune cells. Glial cells also release exosomes, and transmission of exosomes derived from activated glial cells containing inflammatory mediators may contribute to the propagation of the neuroinflammatory response. Glia-to-neuron transmission of exosomes containing alpha-synuclein may contribute to alpha-synuclein propagation and neurodegeneration. Additionally, miRNAs can be transmitted among cells via exosomes inducing changes in the genetic program of the target cell contributing to PD progression. Exosomes also represent a promising drug delivery system. The brain is a difficult target for drugs of all classes because the blood-brain barrier excludes most macromolecular drugs. One of the major challenges is the development of vehicles for robust delivery to the brain. Targeted exosomes may have the potential for delivering therapeutic agents, including proteins and gene therapy molecules, into the brain. This review summarizes recent advances in the role of exosomes in PD pathology progression and their potential use as drug delivery system for PD treatment, the two faces of the exosomes in PD.

BDNF and Netrin-1 repression by C/EBPβ in the gut triggers Parkinson's disease pathologies, associated with constipation and motor dysfunctions

Chronic constipation is one of the most prominent prodromal symptoms in Parkinson's disease (PD), and Lewy bodies, enriched with aggregated α-Synuclein (α-Syn), propagation from the gut into the brain has been proposed to play a key role in PD etiopathogenesis. BDNF (Brain-derived neurotrophic factor) and Netrin-1 promote both neuronal survival and regulate the gut functions. We hypothesize that C/EBPβ represses BDNF and Netrin-1 in peripheral nervous system and central nervous system, contributing to GI tract and brain malfunctions in PD. To test the hypothesis, we performed the studies in both human PD gut tissues and BDNF or Netrin-1 gut conditional KO mice models. Lewy bodies with α-Syn aggregation and neuro-inflammation were measured in the colon and brain samples from PD patients and healthy controls and rotenone or vehicle-treated WT and CEBPβ (+/-) mice. We show that both BDNF and Netrin-1 are strongly decreased in the brain and the gut of PD patients, and conditional KO of these trophic factors in the gut elicits dopaminergic neuronal loss, constipation and motor dysfunctions. Interestingly, the inflammation and oxidative stress-induced transcription factor C/EBPβ acts as a robust repressor for both BDNF and Netrin-1 and suppresses the expression of trophic factors, and its levels inversely correlate with BDNF and Netrin-1 in PD patients. Our findings support that gut inflammation induces C/EBPβ activation that leads to both BDNF and Netrin-1 reduction and triggers PD non-motor and motor symptoms. Possibly, C/EBPβ-mediated biological events might be early diagnostic biomarkers for PD.

Microbial BMAA and the Pathway for Parkinson's Disease Neurodegeneration

The neurotoxin β-N-methylamino-L-alanine (BMAA) is a natural non-proteinogenic diamino acid produced by several species of both prokaryotic (cyanobacteria) and eukaryotic (diatoms and dinoflagellates) microorganisms. BMAA has been shown to biomagnify through the food chain in some ecosystems, accumulating for example in seafood such as shellfish and fish, common dietary sources of BMAA whose ingestion may have possible neuronal consequences. In addition to its excitotoxic potential, BMAA has been implicated in protein misfolding and aggregation, inhibition of specific enzymes and neuroinflammation, all hallmark features of neurodegenerative diseases. However, the exact molecular mechanisms of neurotoxicity remain to be elucidated in detail. Although BMAA is commonly detected in its free form, complex BMAA-containing molecules have also been identified such as the paenilamicins, produced by an insect gut bacterial pathogen. On the other hand, production of BMAA or BMAA-containing molecules by members of the human gut microbiota, for example by non-photosynthetic cyanobacteria, the Melainabacteria, remains only hypothetical. In any case, should BMAA reach the gut it may interact with cells of the mucosal immune system and neurons of the enteric nervous system (ENS) and possibly target the mitochondria. Here, we review the available evidence and hint on possible mechanisms by which chronic exposure to dietary sources of this microbial neurotoxin may drive protein misfolding and mitochondrial dysfunction with concomitant activation of innate immune responses, chronic low-grade gut inflammation, and ultimately the neurodegenerative features observed across the gut-brain axis in Parkinson's disease (PD).

Extracellular Interactions of Alpha-Synuclein in Multiple System Atrophy

Multiple system atrophy, characterized by atypical Parkinsonism, results from central nervous system (CNS) cell loss and dysfunction linked to aggregates of the normally pre-synaptic α-synuclein protein. Mostly cytoplasmic pathological α-synuclein inclusion bodies occur predominantly in oligodendrocytes in affected brain regions and there is evidence that α-synuclein released by neurons is taken up preferentially by oligodendrocytes. However, extracellular α-synuclein has also been shown to interact with other neural cell types, including astrocytes and microglia, as well as extracellular factors, mediating neuroinflammation, cell-to-cell spread and other aspects of pathogenesis. Here, we review the current evidence for how α-synuclein present in the extracellular milieu may act at the cell surface to drive components of disease progression. A more detailed understanding of the important extracellular interactions of α-synuclein with neuronal and non-neuronal cell types both in the brain and periphery may provide new therapeutic targets to modulate the disease process.

The Microbiome-Mitochondria Dance in Prodromal Parkinson's Disease

The brain is an immunologically active organ where neurons and glia cells orchestrate complex innate immune responses against infections and injuries. Neuronal responses involve Toll-like or Nod-like receptors and the secretion of antimicrobial peptides and cytokines. The endosymbiotic theory for the evolutionary origin of mitochondria from primitive bacteria, suggests that they may have also retained the capacity to activate neuronal innate immunity. In fact, it was shown that mitochondrial damage-associated molecular patterns could signal and activate innate immunity and inflammation. Moreover, the mitochondrial cascade hypothesis for sporadic Parkinson’s disease (PD) argues that altered mitochondrial metabolism and function can drive neurodegeneration. Additionally, a neuroinflammatory signature with increased levels of pro-inflammatory mediators in PD affected brain areas was recently detected. Herein, we propose that a cascade of events initiating in a dysbiotic gut microbiome drive the production of toxins or antibiotics that target and damage mitochondria. This in turn activates neuronal innate immunity and triggers sterile inflammation phenomena that culminate in the neurodegenerative processes observed in the enteric and in the central nervous systems and that ultimately lead to Parkinson’s disease.

Depression may negatively affect the change in freezing of gait following subthalamic nucleus stimulation in Parkinson's disease

OBJECTIVE

To assess the influence of preoperative depression on the change in freezing of gait (FOG) following subthalamic nucleus stimulation (STN-DBS) in patients with Parkinson's disease (PD).

METHODS

One hundred and twelve PD patients were included who received bilateral STN-DBS. Of these, 33 had no preoperative depression (PD-ND) and the other 79 had preoperative depression (PD-D). Each PD-ND patient was matched with one PD-D patient by the propensity score for which sex, age at PD onset, disease duration, UPDRS-III score during off-medication state, levodopa-equivalent daily dose, and mini mental state examination were the independent variables. We compared both a FOG-questionnaire (FOG-Q) and the axial score from UPDRS-III between the two groups over 12-month follow-up.

RESULTS

During the off-medication state, FOG-Q at 12-month was decreased with STN-DBS in both PD-ND (-52.9%, p < 0.001) and PD-D (-24.2%, p < 0.001) with a significant difference in the change of FOG in favor of PD-ND (p = 0.001). Similarly, there was an improvement in the axial score for both PD-ND (-66.1%, p < 0.001) and PD-D (-45.3%, p < 0.001) at 12-month with a significant difference between the groups. (p = 0.005). During the on-medication state, both the FOG-Q and axial score at 12-month were not improved with STN-DBS in the PD-ND and PD-D with no difference between the groups.

CONCLUSIONS

Our findings suggest that preoperative depression negatively affects the outcome of FOG following STN-DBS in the off-medication state but not in the on-medication state.

Herpes zoster correlates with increased risk of Parkinson's disease in older people: A population-based cohort study in Taiwan

Little is known on the relationship between herpes zoster and Parkinson's disease in older people. This study aimed to explore whether herpes zoster could be associated with Parkinson's disease in older people in Taiwan.We conducted a retrospective cohort study using the claim data of the Taiwan National Health Insurance Program. There were 10,296 subjects aged 65 years and older with newly diagnosed herpes zoster as the herpes zoster group and 39,405 randomly selected subjects aged 65 years and older without a diagnosis of herpes zoster as the nonherpes zoster group from 1998 to 2010. Both groups were followed up until subjects received a diagnosis of Parkinson's disease. This follow-up design would explore whether subjects with herpes zoster were at an increased risk of Parkinson's disease. Relative risks were estimated by adjusted hazard ratio (HR) and 95% confidence interval (CI) using the multivariable Cox proportional hazards regression model.The incidence of Parkinson's disease was higher in the herpes zoster group than that in the nonherpes zoster group (4.86 vs 4.00 per 1000 person-years, 95% CI 1.14, 1.29). After adjustment for confounding factors, the multivariable Cox proportional hazards regression model revealed that the adjusted HR of Parkinson's disease was 1.17 for the herpes zoster group (95% CI 1.10, 1.25), compared with the nonherpes zoster group.Older people with herpes zoster confer a slightly increased hazard of developing Parkinson's disease when compared to those without herpes zoster. We think that herpes zoster correlates with increased risk of Parkinson's disease in older people. When older people with herpes zoster seek help, clinicians should pay more attention to the development of the cardinal symptoms of Parkinson's disease.

Comorbid conditions associated with Parkinson's disease: A longitudinal and comparative study with Alzheimer disease and control subjects

BACKGROUND AND OBJECTIVE

To study what comorbid conditions were present at baseline and 3years later in a cohort of Spanish Parkinson's disease (PD) patients, to compare comorbidity with both Alzheimer's disease (AD) and control groups and to analyze the role of comorbidity as predictor of mortality.

METHODS

One hundred and forty-seven non-demented PD patients (57.1% males; 70.9±8.6years old) were included in this 36months follow-up (2012-2015), monocenter, evaluation study. The International Classification of Diseases, Tenth Revision (ICD-10), Charlson Index (CI), Comorbidity-Polypharmacy Score (CPS) and Elixhauser Comorbidity Measure (ECM) were used to assess comorbidity at baseline and at 3years. Forty-four AD patients and 44 control subjects were included as comparator groups.

RESULTS

Total number of comorbidities (ICD-10) and polypharmacy at baseline were higher in PD and AD patients than controls (4.4±2.3 vs 5.2±2.4 vs 3.4±1.9 [p=0.001] and 81.6% vs 75% vs 56.8% [p=0.003], respectively). Diseases of the circulatory system (ICD-10/chapter-IX) and endocrine, nutritional and metabolic diseases (ICD-10/chapter-IV) were the most frequent in all groups. There was a significant increase in comorbidity (mean, +1.6±2.8) in all groups (p<0.0001) without differences between them. Seventeen patients died and 8 cases were did not follow-up. Comorbidity was a predictor of death in PD patients after adjust for other covariates (including age, sex, disease duration, disease stage, motor status and non-motor symptoms): ICD-10 (total number of comorbidities), hazard ratio 1.285 (95% confidence interval, 1.047-1.577; p=0.017); CI, hazard ratio 1.462 (95% confidence interval, 1.045-2.047; p=0.027).

CONCLUSIONS

Comorbidity is frequent in PD patients, increases significantly over time and predicts mortality.

Marijuana Compounds: A Nonconventional Approach to Parkinson's Disease Therapy

Parkinson's disease (PD), a neurodegenerative disorder, is the second most common neurological illness in United States. Neurologically, it is characterized by the selective degeneration of a unique population of cells, the nigrostriatal dopamine neurons. The current treatment is symptomatic and mainly involves replacement of dopamine deficiency. This therapy improves only motor symptoms of Parkinson's disease and is associated with a number of adverse effects including dyskinesia. Therefore, there is unmet need for more comprehensive approach in the management of PD. Cannabis and related compounds have created significant research interest as a promising therapy in neurodegenerative and movement disorders. In this review we examine the potential benefits of medical marijuana and related compounds in the treatment of both motor and nonmotor symptoms as well as in slowing the progression of the disease. The potential for cannabis to enhance the quality of life of Parkinson's patients is explored.

Neuroinflammation in the pathophysiology of Parkinson’s disease and therapeutic evidence of anti-inflammatory drugs

Parkinson’s disease (PD) is the second most common neurodegenerative disease affecting approximately 1.6% of the population over 60 years old. The cardinal motor symptoms are the result of progressive degeneration of substantia nigra pars compacta dopaminergic neurons which are involved in the fine motor control. Currently, there is no cure for this pathology and the cause of the neurodegeneration remains unknown. Several studies suggest the involvement of neuroinflammation in the pathophysiology of PD as well as a protective effect of anti-inflammatory drugs both in animal models and epidemiological studies, although there are controversial reports. In this review, we address evidences of involvement of inflammatory process and possible therapeutic usefulness of anti-inflammatory drugs in PD.

The relation between α-synuclein and microglia in Parkinson's disease: Recent developments

Recent research suggests a complex role for microglia not only in Parkinson's disease but in other disorders involving alpha-synuclein aggregation, such as multiple system atrophy. In these neurodegenerative processes, the activation of microglia is a common pathological finding, which disturbs the homeostasis of the neuronal environment otherwise maintained, among others, by microglia. The term activation comprises any deviation from what otherwise is considered normal microglia status, including cellular abundance, morphology or protein expression. The microglial response during disease will sustain survival or otherwise promote cell degeneration. The novel concepts of alpha-synuclein being released and uptaken by neighboring cells, and their importance in disease progression, positions microglia as the main cell that can clear and handle alpha-synuclein efficiently. Microglia's behavior will therefore be a determinant on the disease's progression. For this reason we believe that the better understanding of microglia's response to alpha-synuclein pathological accumulation across brain areas and disease stages is essential to develop novel therapeutic tools for Parkinson's disease and other alpha-synucleinopathies. In this review we will revise the most recent findings and developments with regard to alpha-synuclein and microglia in Parkinson's disease.

Microglial phenotypes and toll-like receptor 2 in the substantia nigra and hippocampus of incidental Lewy body disease cases and Parkinson's disease patients

Next to α-synuclein deposition, microglial activation is a prominent pathological feature in the substantia nigra (SN) of Parkinson's disease (PD) patients. Little is known, however, about the different phenotypes of microglia and how they change during disease progression, in the SN or in another brain region, like the hippocampus (HC), which is implicated in dementia and depression, important non-motor symptoms in PD. We studied phenotypes and activation of microglia in the SN and HC of established PD patients (Braak PD stage 4–6), matched controls (Braak PD stage 0) and of incidental Lewy Body disease (iLBD) cases (Braak PD stage 1–3) that are considered a prodromal state of PD. As recent experimental studies suggested that toll-like receptor 2 (TLR2) mediates α-synuclein triggered microglial activation, we also studied whether TLR2 expression is indeed related to pathology in iLBD and PD patients. A clear α-synuclein pathology-related increase in amoeboid microglia was present in the HC and SN in PD. Also, morphologically primed/reactive microglial cells, and a profound increase in microglial TLR2 expression were apparent in iLBD, but not PD, cases, indicative of an early activational response to PD pathology. Moreover, TLR2 was differentially expressed between the SN and HC, consistent with a region-specific pattern of microglial activation. In conclusion, the regional changes in microglial phenotype and TLR2 expression in primed/reactive microglia in the SN and HC of iLBD cases indicate that TLR2 may play a prominent role in the microglial-mediated responses that could be important for PD progression.

Adult hippocampal neurogenesis in Parkinson's disease: impact on neuronal survival and plasticity

In Parkinson's disease (PD) and other synucleinopathies, chronic neurodegeneration occurs within different areas of the central nervous system leading to progressive motor and nonmotor symptoms. The symptomatic treatment options that are currently available do not slow or halt disease progression. This highlights the need of a better understanding of disease mechanisms and disease models. The generation of newborn neurons in the adult hippocampus and in the subventricular zone/olfactory bulb system is affected by many different regulators and possibly involved in memory processing, depression, and olfaction, symptoms which commonly occur in PD. The pathology of the adult neurogenic niches in human PD patients is still mostly elusive, but different preclinical models have shown profound alterations of adult neurogenesis. Alterations in stem cell proliferation, differentiation, and survival as well as neurite outgrowth and spine formation have been related to different aspects in PD pathogenesis. Therefore, neurogenesis in the adult brain provides an ideal model to study disease mechanisms and compounds. In addition, adult newborn neurons have been proposed as a source of endogenous repair. Herein, we review current knowledge about the adult neurogenic niches in PD and highlight areas of future research.

Targeted discovery and validation of plasma biomarkers of Parkinson's disease

Despite extensive research, an unmet need remains for protein biomarkers of Parkinson's disease (PD) in peripheral body fluids, especially blood, which is easily accessible clinically. The discovery of such biomarkers is challenging, however, due to the enormous complexity and huge dynamic range of human blood proteins, which are derived from nearly all organ systems, with those originating specifically from the central nervous system (CNS) being exceptionally low in abundance. In this investigation of a relatively large cohort (∼300 subjects), selected reaction monitoring (SRM) assays (a targeted approach) were used to probe plasma peptides derived from glycoproteins previously found to be altered in the CNS based on PD diagnosis or severity. Next, the detected peptides were interrogated for their diagnostic sensitivity and specificity as well as the correlation with PD severity, as determined by the Unified Parkinson's Disease Rating Scale (UPDRS). The results revealed that 12 of the 50 candidate glycopeptides were reliably and consistently identified in plasma samples, with three of them displaying significant differences among diagnostic groups. A combination of four peptides (derived from PRNP, HSPG2, MEGF8, and NCAM1) provided an overall area under curve (AUC) of 0.753 (sensitivity: 90.4%; specificity: 50.0%). Additionally, combining two peptides (derived from MEGF8 and ICAM1) yielded significant correlation with PD severity, that is, UPDRS (r = 0.293, p = 0.004). The significance of these results is at least two-fold: (1) it is possible to use a targeted approach to identify otherwise very difficult to detect CNS related biomarkers in peripheral blood and (2) the novel biomarkers, if validated in independent cohorts, can be employed to assist with clinical diagnosis of PD as well as monitoring disease progression.

Tau acts as a mediator for Alzheimer's disease-related synaptic deficits

The two histopathological hallmarks of Alzheimer's disease (AD) are amyloid plaques containing multiple forms of amyloid beta (Aβ) and neurofibrillary tangles containing phosphorylated tau proteins. As mild cognitive impairment frequently occurs long before the clinical diagnosis of AD, the scientific community has been increasingly interested in the roles of Aβ and tau in earlier cellular changes that lead to functional deficits. Therefore, great progress has recently been made in understanding how Aβ or tau causes synaptic dysfunction. However, the interaction between the Aβ and tau-initiated intracellular cascades that lead to synaptic dysfunction remains elusive. The cornerstone of the two-decade-old hypothetical amyloid cascade model is that amyloid pathologies precede tau pathologies. Although the premise of Aβ-tau pathway remains valid, the model keeps evolving as new signaling events are discovered that lead to functional deficits and neurodegeneration. Recent progress has been made in understanding Aβ-PrP(C) -Fyn-mediated neurotoxicity and synaptic deficits. Although still elusive, many novel upstream and downstream signaling molecules have been found to modulate tau mislocalization and tau hyperphosphorylation. Here we will discuss the mechanistic interactions between Aβ-PrP(C) -mediated neurotoxicity and tau-mediated synaptic deficits in an updated amyloid cascade model with calcium and tau as the central mediators.

Antiparkinson drug adherence and its association with health care utilization and economic outcomes in a Medicare Part D population

OBJECTIVES

We examine the associations of adherence to antiparkinson drugs (APDs) with health care utilization and economic outcomes among patients with Parkinson's disease (PD).

METHODS

By using 2006-2007 Medicare administrative data, we examined 7583 beneficiaries with PD who filled two or more APD prescriptions during 19 months (June 1, 2006, to December 31, 2007) in the Part D program. Two adherence measures--duration of therapy (DOT) and medication possession ratio (MPR)--were assessed. Negative binomial and gamma generalized linear models were used to estimate the rate ratios (RRs) of all-cause health care utilization and expenditures, respectively, conditional upon adherence, adjusting for survival risk, sample selection, and health-seeking behavior.

RESULTS

Approximately one-fourth of patients with PD had low adherence (MPR < 0.80, 28.7%) or had a short DOT (≤ 400 days, 23.9%). Increasing adherence to APD therapy was associated with decreased health care utilization and expenditures. For example, compared with patients with low adherence, those with high adherence (MPR = 0.90-1.00) had significantly lower rates of hospitalization (RR = 0.86), emergency room visits (RR = 0.91), skilled nursing facility episodes (RR = 0.67), home health agency episodes (RR = 0.83), physician visits (RR = 0.93), as well as lower total health care expenditures (-$2242), measured over 19 months. Similarly, lower total expenditure (-$6308) was observed in patients with a long DOT versus those with a short DOT.

CONCLUSIONS

In this nationally representative sample, higher adherence to APDs and longer duration of use of APDs were associated with lower all-cause health care utilization and total health care expenditures. Our findings suggest the need for improving medication-taking behaviors among patients with PD to reduce the use of and expenditures for medical resources.

A disruption mechanism of the molecular clock in a MPTP mouse model of Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disorder that is characterized by the degeneration of dopaminergic neurons in the substantia nigra and dopamine depletion in the striatum. Although the motor symptoms are still regarded as the main problem, non-motor symptoms in PD also markedly impair the quality of life. Several non-motor symptoms, such as sleep disturbances and depression, are suggested to be implicated in the alteration in circadian clock function. In this study, we investigated circadian disruption and the mechanism in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. MPTP-treated mice exhibited altered 24-h rhythms in body temperature and locomotor activity. In addition, MPTP treatment also affected the circadian clock system at the genetic level. The exposure of human neuroblastoma cells (SH-SY5Y) to 1-metyl-4-phenylpyridinium (MPP(+)) increased or decreased the mRNA levels of several clock genes in a dose-dependent manner. MPP(+)-induced changes in clock genes expression were reversed by Compound C, an inhibitor of AMP-activated protein kinase (AMPK). Most importantly, addition of ATP to the drinking water of MPTP-treated mice attenuated neurodegeneration in dopaminergic neurons, suppressed AMPK activation and prevented circadian disruption. The present findings suggest that the activation of AMPK caused circadian dysfunction, and ATP may be a novel therapeutic strategy based on the molecular clock in PD.

Social brain dysfunctions in patients with Parkinson's disease: a review of theory of mind studies

Human social interaction is essential in daily life and crucial for a promising life, especially in people who suffer from disease. Theory of Mind (ToM) is fundamental in social interaction and is described as the ability to impute the mental states of others in social situations. Studies have proposed that a complex neuroanatomical network that includes the frontal cortex mediates ToM. The primary neuropathology of Parkinson’s disease (PD) involves the frontal-striatal system; therefore, patients with PD are expected to exhibit deficits in ToM. In this review, we summarize the current research with a particular focus on the patterns of impaired ToM, potential mediators of ToM, and the impact of ToM deficits on clinical disability in PD. Further studies to investigate the progression of ToM and its relationship with dementia in subjects in PD are needed.

Morbidities in rapid eye movement sleep behavior disorder

Idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD, RBD without any obvious comorbid major neurological disease), is strongly associated with numerous comorbid conditions. The most prominent is that with neurodegenerative disorders, especially synuclein-mediated disorders, above all Parkinson disease (PD). Idiopathic RBD is an important risk factor for the development of synucleinopathies. Comorbidity studies suggest that iRBD is associated with a number of other potential pre-motor manifestations of synucleinopathies such as, cognitive and olfactory impairment, reduced autonomic function, neuropsychiatric manifestations and sleep complaints. Furthermore, patients with PD and RBD may have worse prognosis in terms of impaired cognitive function and overall morbidity/mortality; in dementia, the presence of RBD is strongly associated with clinical hallmarks and pathological findings of dementia with Lewy bodies. These findings underline the progressive disease process, suggesting involvement of more brain regions in patients with a more advanced disease stage. RBD is also associated with narcolepsy, and it is likely that RBD associated with narcolepsy is a distinct subtype associated with different comorbidities. RBD is also associated with antidepressant medications, autoimmune conditions, and, in rare cases, brainstem lesions.

Emerging roles of microglial activation and non-motor symptoms in Parkinson's disease

Recent data has indicated that the traditional view of Parkinson's disease (PD) as an isolated disorder of the nigrostriatal dopaminergic system alone is an oversimplification of its complex symptomatology. Aside from classical motor deficits, various non-motor symptoms including autonomic dysfunction, sensory and cognitive impairments as well as neuropsychiatric alterations and sleep disturbances are common in PD. Some of these non-motor symptoms can even antedate the motor problems. Many of them are associated with extranigral neuropathological changes, such as extensive α-synuclein pathology and also neuroinflammatory responses in specific brain regions, i.e. microglial activation, which has been implicated in several aspects of PD pathogenesis and progression. However, microglia do not represent a uniform population, but comprise a diverse group of cells with brain region-specific phenotypes that can exert beneficial or detrimental effects, depending on the local phenotype and context. Understanding how microglia can be neuroprotective in one brain region, while promoting neurotoxicity in another, will improve our understanding of the role of microglia in neurodegeneration in general, and of their role in PD pathology in particular. Since neuroinflammatory responses are in principle modifiable, such approaches could help to identify new targets or adjunctive therapies for the full spectrum of PD-related symptoms.

Neurologists' diagnostic accuracy of depression and cognitive problems in patients with parkinsonism

Background

Depression and cognitive impairment (CI) are important non-motor symptoms in Parkinson’s Disease (PD) and related syndromes, but it is not clear how well they are recognised in daily practice. We have studied the diagnostic performance of experienced neurologists on the topics depression and cognitive impairment during a routine encounter with a patient with recent-onset parkinsonian symptoms.

Methods

Two experienced neurologists took the history and examined 104 patients with a recent-onset parkinsonian disorder, and assessed the presence of depression and cognitive impairment. On the same day, all patients underwent a Hamilton Depression Rating Scale test, and a Scales for Outcomes in Parkinson’s Disease-Cognition-test (SCOPA-COG).

Results

The sensitivity of the neurologists for the topic depression was poor: 33.3%. However, the specificity varied from 90.8 to 94.7%. The patients’ sensitivity was higher, although the specificity was lower. On the topic CI, the sensitivity of the neurologists was again low, in a range from 30.4 up to 34.8%: however the specificity was high, with 92.9%. The patients’ sensitivity and specificity were both lower, compared to the number of the neurologists.

Conclusions

Neurologists’ intuition and clinical judgment alone are not accurate for detection of depression or cognitive impairment in patients with recent-onset parkinsonian symptoms because of low sensitivity despite of high specificity.

Trial registration

(ITRSCC)NCT0036819.

Pegylated granulocyte colony-stimulating factor conveys long-term neuroprotection and improves functional outcome in a model of Parkinson's disease

Recent proof-of-principle data showed that the haematopoietic growth factor granulocyte colony-stimulating factor (filgrastim) mediates neuroprotection in rodent models of Parkinson's disease. In preparation for future clinical trials, we performed a preclinical characterization of a pegylated derivative of granulocyte colony-stimulating factor (pegfilgrastim) in the mouse 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinson's disease. We determined serum and cerebrospinal fluid drug levels after subcutaneous injection. A single injection of pegfilgrastim was shown to achieve stable levels of granulocyte colony-stimulating factor in both serum and cerebrospinal fluid with substantially higher levels compared to repetitive filgrastim injections. Leucocyte blood counts were only transiently increased after repeated injections. We demonstrated substantial dose-dependent long-term neuroprotection by pegfilgrastim in both young and aged mice, using bodyweight-adjusted doses that are applicable in clinical settings. Importantly, we found evidence for the functionally relevant preservation of nigrostriatal projections by pegfilgrastim in our model of Parkinson's disease, which resulted in improved motor performance. The more stable levels of pegylated neuroprotective proteins in serum and cerebrospinal fluid may represent a general advantage in the treatment of chronic neurodegenerative diseases and the resulting longer injection intervals are likely to improve patient compliance. In summary, we found that pegylation of a neuroprotective growth factor improved its pharmacokinetic profile over its non-modified counterpart in an in vivo model of Parkinson's disease. As the clinical safety profile of pegfilgrastim is already established, these data suggest that evaluation of pegfilgrastim in further Parkinson's disease models and ultimately clinical feasibility studies are warranted.

First neuropathological description of a patient with Parkinson's disease and LRRK2 p.N1437H mutation

The c.4309A>C mutation in the LRRK2 gene (LRRK2 p.N1437H) has recently been reported as the seventh pathogenic LRRK2 mutation causing monogenic Parkinson's disease (PD). So far, only two families worldwide have been identified with this mutation. By screening DNA from seven brains of PD patients, we found one individual with seemingly sporadic PD and LRRK2 p.N1437H mutation. Clinically, the patient had levodopa-responsive PD with tremor, and developed severe motor fluctuations during a disease duration of 19 years. There was severe and painful ON-dystonia, and severe depression with suicidal thoughts during OFF. In the advanced stage, cognition was slow during motor OFF, but there was no noticeable cognitive decline. There were no signs of autonomic nervous system dysfunction. Bilateral deep brain stimulation of the subthalamic nucleus had unsatisfactory results on motor symptoms. The patient committed suicide. Neuropathological examination revealed marked cell loss and moderate alpha-synuclein positive Lewy body pathology in the brainstem. There was sparse Lewy pathology in the cortex. A striking finding was very pronounced ubiquitin-positive pathology in the brainstem, temporolimbic regions and neocortex. Ubiquitin positivity was most pronounced in the white matter, and was out of proportion to the comparatively weaker alpha-synuclein immunoreactivity. Immunostaining for tau was mildly positive, revealing non-specific changes, but staining for TDP-43 and FUS was entirely negative. The distribution and shape of ubiquitin-positive lesions in this patient differed from the few previously described patients with LRRK2 mutations and ubiquitin pathology, and the ubiquitinated protein substrate remains undefined.

Does WOQ-9 help to recognize symptoms of non-motor wearing-off in Parkinson's disease?

EWO (Epidemiology of Wearing-Off symptoms among the population of Parkinson's disease (PD) patients on L-DOPA) is a multicentric, non-interventional, epidemiological and exploratory trial, focused on patients with PD who are treated with L-DOPA. The primary objective is the estimation of wearing-off symptoms (based on WOQ-9 questionnaire and assessment by neurologists) among PD patients who are treated with L-DOPA. From September 30, 2007 to June 30, 2008 altogether 563 valid records of PD patients were collected in movement disorders centers (Level A and Level B centers). Wearing-off symptoms were observed in 66.7% of PD patients (neurologists' assessment) and in 90.6% of PD patients (WOQ-9 questionnaire). The biggest discrepancy was found in PD patients treated with L-DOPA for 0-2 years. The probability of detecting wearing-off by the neurologists strongly correlated with the highest number of positive responses in the WOQ-9 marked by PD patients. There was significant difference in the diagnosis of wearing-off between Level A centers (77.7%) and Level B centers (62.0%). When motor and non-motor symptoms in the WOQ-9 were considered, the difference between neurologists came from the detection of non-motor symptoms (lower in the Level B centers). The neurologists' assessment of wearing-off symptoms and PD patients' subjective evaluation of the WOQ-9 is based on the experience of the neurologist and on the detection of the non-motor symptoms of wearing-off. Careful explanation of the WOQ-9 questionnaire and improved awareness of the non-motor symptoms of wearing-off is strongly suggested.

A family with Parkinsonism, essential tremor, restless legs syndrome, and depression

BACKGROUND

Previous epidemiologic and genetic studies have suggested a link between Parkinson disease (PD), essential tremor (ET), and restless legs syndrome (RLS).

METHODS

We describe the clinical, PET, and pathologic characteristics of an extensive kindred from Arkansas with hereditary PD, ET, and RLS. The pedigree contains 138 individuals. Sixty-five family members were examined neurologically up to 3 times from 2004 to 2010. Clinical data were collected from medical records and questionnaires. Genetic studies were performed. Five family members underwent multitracer PET. Two individuals with PD were examined postmortem.

RESULTS

Eleven family members had PD with generally mild and slowly progressive symptoms. Age at onset was between 39 and 74 years (mean 59.1, SD 13.4). All individuals treated with l-dopa responded positively. Postural or action tremor was present in 6 individuals with PD, and in 19 additional family members. Fifteen persons reported symptoms of RLS. PET showed reduced presynaptic dopamine function typical of sporadic PD in a patient with PD and ET, but not in persons with ET or RLS. The inheritance pattern was autosomal dominant for PD and RLS. No known pathogenic mutation in PD-related genes was found. Fourteen of the family members with PD, ET, or RLS had depression. Neuropathologic examination revealed pallidonigral pigment spheroid degeneration with ubiquitin-positive axonal spheroids, TDP43-positive pathology in the basal ganglia, hippocampus, and brainstem, and only sparse Lewy bodies.

CONCLUSION

Familial forms of PD, ET, RLS, and depression occur in this family. The genetic cause remains to be elucidated.

View point: etiology in Parkinson's disease. Dual hit or spreading intoxication

Parkinson's disease is not only a movement disorder: non-motor symptoms such as loss of smell, constipation, depression, cognitive impairment, sleep problems and disturbances of the autonomic nervous system also feature. The etiology is still unknown, although an increasing number of gene-related Parkinsonian syndromes have been identified. It is intriguing to speculate that PD starts by the intake of a toxin, bacteria or virus. This idea stems from the fact that pathological abnormalities such as Lewy neuritis, Lewy bodies and alpha-synuclein accumulation are first found in the enteric nervous system of the gut and in the olfactory bulb. There is increasing evidence that the disease may spread out from the enteric nervous system of the gut via the vagal nerve up to the brain. Here we present data from animal work which supports this assumption.