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ABSTRACTIntroductionParkinson’s disease (PD) is the second most common neurodegenerative disease worldwide. The median age of disease onset is around 60 years. From a genetic point of view, PD is basically considered a sporadic, idiopathic disease, however, hereditary components can be detected in 5–10% of patients. Expanding data are available regarding the targeted molecular therapy of the disease.Areas coveredThe aim of this current review article is to provide brief clinical and molecular insight into three important genetic forms (LRRK2, SNCA, GBA) of hereditary PD subtypes and to present the human clinical trials in relation to these forms of the disease.Expert opinionThese small hereditary subgroups are crucially important in drug development, because the general trend is that clinical trials that treat PD patients as a large group, without any separation, do not meet expectations. As a result, no long term conclusions can currently be drawn regarding the effectiveness of the molecules tested in these phase 1 and 2 studies. Further precise studies are needed in the near future.

Parkinson’s disease (PD) is the second most common neurodegenerative disease worldwide. Considering the devastating symptoms, high prevalence, and lack of definitive diagnostic test, there is an urgent need to identify possible biomarkers and new therapeutic targets. Genes identified and/or proposed to be linked to PD encode proteins that fulfill diverse roles in cellular functions. There is a growing interest in identifying common traits which lead to the disease. Long non-coding RNAs have recently emerged as possible regulatory hubs of complex molecular changes affecting PD development. Among them, NEAT1 has attracted particular interest. It is a major component and the initiator of nuclear paraspeckles, thus regulating transcription and modifying protein functions. This review summarizes data available on the role of NEAT1 in PD. NEAT1 upregulation in PD has repeatedly been reported, however, whether this is part of a protective or a damaging mechanism is still a topic of debate. It has been proposed that NEAT1 propagates PD viaits interaction with PINK1 and several micro RNAs and by modulating SNCAexpression. On the other hand, findings of NEAT1 acting as a bona fide LRRK2 inhibitor argue for its protective role. These contradictory results could be due to the different disease models implemented. This calls attention to the difficulties posed by the complex patho-mechanisms of neurodegenerative disorders and the limitations of disease models. However, the potential of NEAT1 as a biomarker and as a therapeutic target for PD highly warrants further research to elucidate its exact role in this neurodegenerative disorder.

ABSTRACTIntroductionParkinson’s disease (PD) is a progressive, chronic neurodegenerative disorder. The main neuropathological cause of the disease is the death of dopaminergic neurons in the substantia nigra. Unfortunately, there is no curative treatment yet. The gold-standard of the treatment is levodopa (LD). During the course of the disease, motor complications develop, which postulates the addition of entacapone (ENT) to the dopaminergic medication. Previous studies have suggested that patients have a better quality of life when entacapone is added in a combination with LD.Areas coveredA systematic literature search was performed. Articles were identified through PubMed (MEDLINE), Web of Science, Ovid, and ClinicalTrials.gov databases. The following search terms were used: ‘Levodopa’ AND ‘Carbidopa’ OR ‘Benserazide’ AND ‘Entacapone’. The search period was between 2000 and 2020. Twenty randomized and 10 non-randomized clinical trials (12,893 subjects) were included in the qualitative analysis. The systematic review was written in line with the PRISMA guideline.Expert opinionENT administered in combination with LD resulted in a better quality of life compared to separate tablets. Therefore, in PD patients where impaired motor performance develops and the application of entacapone is necessary, it is suggested to be administered in a single tablet form.

ABSTRACTIntroduction: Parkinson’s disease is a neurodegenerative disorder which is characterized by the combination of motor and non-motor symptoms. As yet, there is no curative treatment. The gold standard for symptom control is levodopa. Two years after the start of substitution therapy, around 50% of patients experience some degree of fluctuation in motor performance. Catechol-O-methyltransferase (COMT) inhibitors are important agents in treating these fluctuations.Areas covered: This article summarizes our knowledge about a new third-generation COMT inhibitor, namely opicapone (OPC) (Search period: 2016–2019). The authors detail the pharmacological profile of OPC and summarize the results of completed clinical trials. In addition, they briefly summarize the achievements of the past few years.Expert opinion: Based on clinical trials conducted so far, OPC is an effective and safe new drug. In comparison to entacapone and tolcapone, it does not require close laboratory monitoring or multiple oral administrations, which may result in better adherence. No serious adverse event was reported during the drug development phases. Dyskinesia was the most common complaint. Further comparative studies and broader trial inclusion criteria are needed to help the decision between COMT inhibitors and to expand the patient spectrum where this drug can be applied.

ABSTRACTIntroduction: Huntington’s disease (HD) is an autosomal dominant, neurodegenerative disorder. Despite the severe motor, psychiatric and cognitive symptoms and the great socioeconomic burden caused by the disease, available treatment is mainly symptomatic.The kynurenine pathway (KP) is the main metabolic route of tryptophan degradation, in the course of which several neuroactive compounds are generated. The imbalance of the neurotoxic and neuroprotectant metabolites can lead to excitotoxicity and overproduction of reactive oxygen species, which both contribute to the progression of HD. Indoleamine 2,3-dioxygenase 1 (IDO1) is a key enzyme of the KP that has various immune modulatory roles.Areas covered: Current knowledge of the involvement of KP in HD pathogenesis with a particular focus on IDO1. By reviewing the diverse roles of the enzyme in kynurenine production, immune modulation, and serotonin metabolism, we elucidate the factors that make this enzyme a therapeutic target.Expert opinion: Due to the complexity of HD and the various effects that IDO1 exerts, targeting this enzyme, while highly profitable, may be a great challenge. Through IDO1 activity, neurodegeneration, inflammatory processes and depressive symptoms, often related to HD, can be modulated. Ongoing trials of IDO1 inhibitors in other areas of medicine offer advantages for initiating approaches toward this enzyme as a therapeutic target.Trial registration:ClinicalTrials.gov identifier: NCT02855476.Trial registration:ClinicalTrials.gov identifier: NCT02519036.

•First assessment on real-world operation of MS centres in Central-Eastern Europe•A self-report questionnaire was used to assess MS care unit recommendations•Data on DMT and registry use, and MS care systems were collected•Homogeneously and heterogeneously available and absent conditions were identified•A strictly regulated centre-system might ensure appropriate care for people with MS

ABSTRACTIntroduction: The proven pathological alterations in the kynurenine pathway of tryptophan metabolism, either in preclinical models of neurological and psychiatric disorders or in human samples themselves, elicited numerous attempts to restore the altered balance via pharmaceutical manipulation of the pathway.Areas covered: The aim of the authors was to conduct a review of relevant scientific data on enzyme inhibitors of the kynurenine pathway, with special attention to pipeline drug development strategies based on relevant patent literature, covering the period of 2012–2015. Considering the magnitude of the topic, only the most prominent examples of lead compounds and substances necessary to enlighten structure activity relationships were reported.Expert opinion: Although the clinical and preclinical data are reassuring, there is a lack of applicable drugs in daily clinical practice. However, the recent determination of enzyme structures considerably promoted the development of potent inhibitors, most of them having been designed as a structural analog of the natural enzyme substrate. Especially, the inhibition of indolamine 2,3-dioxygenase in central nervous system tumors, the inhibition of kynurenine aminotransferase in cognitive dysfunction, and the inhibition of kynurenine 3-monooxygenase in neurodegenerative disorders, such as Huntington’s disease, each show great promise.

Introduction: Drug-induced movement disorders (DIMDs) can be elicited by several kinds of pharmaceutical agents. The major groups of offending drugs include antidepressants, antipsychotics, antiepileptics, antimicrobials, antiarrhythmics, mood stabilisers and gastrointestinal drugs among others.Areas covered:This paper reviews literature covering each movement disorder induced by commercially available pharmaceuticals. Considering the magnitude of the topic, only the most prominent examples of offending agents were reported in each paragraph paying a special attention to the brief description of the pathomechanism and therapeutic options if available.Expert opinion:As the treatment of some DIMDs is quite challenging, a preventive approach is preferable. Accordingly, the use of the offending agents should be strictly limited to appropriate indications and they should be applied in as low doses and as short duration as the patient’s condition allows. As most of DIMDs are related to an unspecific adverse action of medications in the basal ganglia and the cerebellum, future research should focus on better characterisation of the neurochemical profile of the affected functional systems, in addition to the development of drugs with higher selectivity and better side-effect profile.

•Diffusion parameters predicting performance on SDMT and BVMT tests could be well separated from those related to CVLT.•Patterns of diffusion parameters representing demyelination and axonal damage in certain spatial arrangements corresponds to cognitive dysfunctions.•About one quarter of the cognitive impairment's variance may be explained by putative axonal damage in MS, which has presumably little potential for regeneration.

Free radical action has been suggested as a causal factor in multiple sclerosis. We investigated the plasma level of lipid peroxides expressed in terms of malone dialdehyde and changes in blood nonenzymatic antioxidants (glutathione, α-tocopherol, retinol, plasma sulfhydryl groups, and uric acid) in multiple sclerosis patients with exacerbation or in remission, including a group treated with β-interferon. The malone dialdehyde level was increased by 38% (n.s.) during exacerbations. The blood concentration of oxidized glutathione was likewise elevated (P< 0.05), while the ratio of plasma α-tocopherol to cholesterol plus triglyceride was decreased (P< 0.001). These changes suggest increased free radical production and consumption of the scavenger molecules during the active phase of the disease. Blood reduced glutathione level was increased (P< 0.01) during exacerbation and remission as well. The rise in this thiol is likely to be a compensatory mechanism defending the cells from further oxidant injuries. β-Interferon increased plasma α-tocopherol levels (P< 0.001) but not the lipid corrected α-tocopherol value. Other parameters were not influenced by the drug.

Parkinson’s disease (PD) is a common neurodegenerative disorder characterized by bradykinesia, resting tremor, and muscle rigidity. To date, approximately 50 genes have been implicated in PD pathogenesis, including both Mendelian genes with rare mutations and low-penetrance genes with common polymorphisms. Previous studies of low-penetrance genes focused on protein-coding genes, and less attention was given to long noncoding RNAs (lncRNAs). In this study, we aimed to investigate the susceptibility roles of lncRNA gene polymorphisms in the development of PD. Therefore, polymorphisms (n=15) of the PINK1-AS, UCHL1-AS, BCYRN1, SOX2-OT, ANRIL and HAR1A lncRNAs genes were genotyped in Hungarian PD patients (n=160) and age- and sex-matched controls (n=167). The rare allele of the rs13388259 intergenic polymorphism, located downstream of the BCYRN1 gene, was significantly more frequent among PD patients than control individuals (OR = 2.31; p=0.0015). In silico prediction suggested that this polymorphism is located in a noncoding region close to the binding site of the transcription factor HNF4A, which is a central regulatory hub gene that has been shown to be upregulated in the peripheral blood of PD patients. The rs13388259 polymorphism may interfere with the binding affinity of transcription factor HNF4A, potentially resulting in abnormal expression of target genes, such as BCYRN1.

Background. There is substantial evidence that the kynurenine pathway (KP) plays a role in the normal physiology of the brain and is involved in the pathology of neurodegenerative disorders such as Huntington’s disease and Parkinson’s disease (PD). Objective. We set out to investigate the potential roles in PD of single nucleotide polymorphisms (SNPs) from one of the key enzymes of the KP, kynurenine 3-monooxygenase (KMO). Methods. 105 unrelated, clinically definitive PD patients and 131 healthy controls were enrolled to investigate the possible effects of the different alleles of KMO. Fluorescently labeled TaqMan probes were used for allele discrimination. Results. None of the four investigated SNPs proved to be associated with PD or influenced the age at onset of the disease. Conclusions. The genetic link between the KP and PD is still missing. The investigated SNPs presumably do not appear to influence the function of KMO and probably do not contain binding sites for regulatory proteins of relevance in PD. This is the first study to assess the genetic background behind the biochemical alterations of the kynurenine pathway in PD, directing the attention to this previously unexamined field.

Movement Disorder Society-sponsored Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) has separate items for measuring sleep problems (item 1.7) and daytime sleepiness (1.8). The aim of our study was to evaluate the screening sensitivity and specificity of these items to the PD Sleep Scale 2nd version (PDSS-2) and Epworth Sleepiness Scale (ESS). In this nationwide, cross-sectional study 460 PD patients were enrolled. Spearman’s rank correlation coefficients were calculated between the individual items, domains, and the total score of PDSS-2 and item 1.7 of MDS-UPDRS. Similarly, the items and the total score of ESS were contrasted to item 1.8 of MDS-UPDRS. After developing generalized ordinal logistic regression models, the transformed and observed scores were compared by Lin’s Concordance Correlation Coefficient. Only item 3 difficulties staying asleep and the “disturbed sleep” domain of PDSS-2 showed high correlation with “sleep problems” item 1.7 of the MDS-UPDRS. Total score of PDSS-2 had moderate correlation with this MDS-UPRDS item. The total score of ESS showed the strongest, but still moderate, correlation with “daytime sleepiness” item 1.8 of MDS-UPDRS. As intended, the MDS-UPDRS serves as an effective screening tool for both sleep problems and daytime sleepiness and identifies subjects whose disabilities need further investigation.