Levodopa-carbidopa intestinal gel infusion (LCIG) in Parkinson disease with genetic mutations.

BACKGROUND: Levodopa-carbidopa intestinal gel infusion (LCIG) is a therapeutic option for advanced Parkinson disease (PD) patients with troublesome motor complications, unresponsive to conventional oral treatment. There is some evidence to suggest that the genetic background may influence the clinical presentation and rate of progression of PD. Whether the genetic background influences the outcome of device-assisted therapies is currently debated. Some studies have investigated the effectiveness of deep brain stimulation (DBS) in PD patients with different genetic background, while evidence is lacking regarding LCIG. METHODS: A cohort of LCIG patients underwent genetic testing. The motor and neuropsychological outcomes of LCIG were retrospectively analyzed. RESULTS: Fifty-six patients were analyzed, nine of them (15%) had at least one mutation/variant in a PD-associated gene: five GBA1, two SNCA, one LRRK2, one PRKN; 13 (23%) carried the BDNF Val66Met polymorphism. The mean duration of follow-up was 4.9 ± 2.6 years. There were no significant differences in motor or neuropsychological outcomes between patients with and without these gene mutations/variants. No cognitive worsening was observed at follow-up among GBA-PD patients, and they responded well to LCIG in terms of motor symptoms. CONCLUSIONS: Overall, we observed a significant benefit in terms of motor complications in our cohort, including patients carrying genetic mutations/variants. Due to the small sample and limited number of patients carrying genetic mutations/variants, no definitive conclusions can be drawn yet on the genotype impact on LCIG outcome. A careful selection of patients, regardless of the genetic background, is pivotal for an optimal outcome of LCIG.

Genetic causes of PD: A pathway to disease modification.

The underline neuropathology of Parkinson disease is pleiomorphic and its genetic background diverse. Possibly because of this heterogeneity, no effective disease modifying therapy is available. In this paper we give an overview of the genetics of Parkinson disease and explain how this is relevant for the development of new therapies. This article is part of the special issue entitled 'The Quest for Disease-Modifying Therapies for Neurodegenerative Disorders'.

Parkinson disease.

Parkinson disease (PD) is the most common neurodegenerative movement disorder. In Europe, prevalence and incidence rates for PD are estimated at approximately 108-257/100 000 and 11-19/100 000 per year, respectively. Risk factors include age, male gender and some environmental factors. The aetiology of the disease in most patients is unknown, but different genetic causes have been identified. Although familial forms of PD account for only 5%-15% of cases, studies on these families provided interesting insight on the genetics and the pathogenesis of the disease allowing the identification of genes implicated in its pathogenesis and offering critical insights into the mechanisms of disease. The cardinal motor symptoms of PD are tremor, rigidity, bradykinesia/akinesia and postural instability, but the clinical picture includes other motor and non-motor symptoms. Its diagnosis is principally clinical, although specific investigations can help the differential diagnosis from other forms of parkinsonism. Pathologically, PD is characterized by the loss of dopaminergic neurons in the pars compacta of the substantia nigra and by accumulation of misfolded α-synuclein, which is found in intra-cytoplasmic inclusions called Lewy bodies. Currently available treatments offer good control of motor symptoms but do not modify the evolution of the disease. This article is intended to provide a comprehensive, general and practical review of PD for the general neurologist.

Neurological effects of glucocerebrosidase gene mutations.

The association between Gaucher disease (GD) and Parkinson disease (PD) has been described for almost two decades. In the biallelic state (homozygous or compound heterozygous) mutations in the glucocerebrosidase gene (GBA) may cause GD, in which glucosylceramide, the sphingolipid substrate of the glucocerebrosidase enzyme (GCase), accumulates in visceral organs leading to a number of clinical phenotypes. In the biallelic or heterozygous state, GBA mutations increase the risk for PD. Mutations of the GBA allele are the most significant genetic risk factor for idiopathic PD, found in 5%-20% of idiopathic PD cases depending on ethnicity. The neurological consequences of GBA mutations are reviewed and the proposition that GBA mutations result in a disparate but connected range of clinically and pathologically related neurological features is discussed. The literature relating to the clinical, biochemical and genetic basis of GBA PD, type 1 GD and neuronopathic GD is considered highlighting commonalities and distinctions between them. The evidence for a unifying disease mechanism is considered.

Effects of ambroxol on the autophagy-lysosome pathway and mitochondria in primary cortical neurons.

Glucocerebrosidase (GBA1) mutations are the major genetic risk factor for Parkinson's Disease (PD). The pathogenic mechanism is still unclear, but alterations in lysosomal-autophagy processes are implicated due to reduction of mutated glucocerebrosidase (GCase) in lysosomes. Wild-type GCase activity is also decreased in sporadic PD brains. Small molecule chaperones that increase lysosomal GCase activity have potential to be disease-modifying therapies for GBA1-associated and sporadic PD. Therefore we have used mouse cortical neurons to explore the effects of the chaperone ambroxol. This chaperone increased wild-type GCase mRNA, protein levels and activity, as well as increasing other lysosomal enzymes and LIMP2, the GCase transporter. Transcription factor EB (TFEB), the master regulator of the CLEAR pathway involved in lysosomal biogenesis was also increased upon ambroxol treatment. Moreover, we found macroautophagy flux blocked and exocytosis increased in neurons treated with ambroxol. We suggest that ambroxol is blocking autophagy and driving cargo towards the secretory pathway. Mitochondria content was also found to be increased by ambroxol via peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1-α). Our data suggest that ambroxol, besides being a GCase chaperone, also acts on other pathways, such as mitochondria, lysosomal biogenesis, and the secretory pathway.

Past, present, and future of Parkinson's disease: A special essay on the 200th Anniversary of the Shaking Palsy.

This article reviews and summarizes 200 years of Parkinson's disease. It comprises a relevant history of Dr. James Parkinson's himself and what he described accurately and what he missed from today's perspective. Parkinson's disease today is understood as a multietiological condition with uncertain etiopathogenesis. Many advances have occurred regarding pathophysiology and symptomatic treatments, but critically important issues are still pending resolution. Among the latter, the need to modify disease progression is undoubtedly a priority. In sum, this multiple-author article, prepared to commemorate the bicentenary of the shaking palsy, provides a historical state-of-the-art account of what has been achieved, the current situation, and how to progress toward resolving Parkinson's disease. © 2017 International Parkinson and Movement Disorder Society.

The timing of deep brain stimulation for Parkinson disease in the UK from 1997 to 2012.

BACKGROUND AND PURPOSE: Deep brain stimulation (DBS) for Parkinson disease (PD) has traditionally been reserved for the late stages of the disease. There is evidence that DBS is also effective if applied earlier in the disease course. Changes in the frequency of DBS procedures in the UK over a 15-year period were investigated. METHODS: A retrospective review was performed of patient age and disease duration for DBS surgery for PD in UK neurosurgical units from 1997 to 2012 using departmental databases. RESULTS: The number of DBS procedures in the UK increased from three in 1997 to over 80 per year during this period. The mean age at the time of surgery (60 years) and the mean duration of PD at the time of DBS (11 years) remained unchanged over 15 years. CONCLUSIONS: The age and disease duration at which DBS is performed for PD in the UK has been static over a 15-year period and DBS appears to remain a therapy for PD applied late in its course. This may change in the light of clinical evidence suggesting a benefit for earlier DBS.

Practical recommendations for the process of proposing, planning and writing a neurological management guideline by EAN task forces.

The European Academy of Neurology (EAN), founded in 2014 after the merging of the two previously active European Neurological Societies, considers the production of neurological guidelines a major obligation, as this is a major tool to improve clinical practice in neurology. This paper updates practical suggestions to develop guidelines about the treatment and diagnosis of neurological diseases within the framework of the EAN. Its aim is to make uniform, traceable and explicit the path from the decision to write an EAN guideline to its publication. We explain the protocol structure, handling of conflicts of interest, format, timeline and process of revision and acceptance. It provides the view of the Scientific Committee and the Board of the EAN. We hope to make easier a larger involvement of the EAN scientific community in producing guidelines.

The burden of non-motor symptoms in Parkinson's disease using a self-completed non-motor questionnaire: a simple grading system.

BACKGROUND: Non-motor symptoms (NMS) of Parkinson's disease (PD) affect virtually every patient, yet they are under-recognized and under-treated. The NMS Questionnaire (NMSQuest) is a validated 30-item self-assessment instrument useful for NMS screening in clinic. OBJECTIVE: Development of a straight forward grading classification of the burden of non-motor symptoms in PD based on the number of NMS as assessed by the NMS Questionnaire. METHODS: In an observational, cross-sectional, international study of 383 consecutive patients distribution of the declared NMS as per NMSQuest was analyzed according to previously published levels based on the Non-Motor Symptoms Scale and also the median and interquartile range (IR, percentiles 25 and 75) of the total NMSQuest scores. After post hoc checking, these values were proposed as cut-off points for estimating NMS burden based only on the accumulation of symptoms. RESULTS: Burden and number of NMS correlate closely (r ≥ 0.80). On the basis of this finding, five levels (0 = No NMS to 4 = Very severe) of NMSQuest grading were proposed after identification of their cut-offs by ordinal logistic regression and median and interquartile range distribution. These values coincided almost completely with those obtained by median and interquartile range in an independent sample. Concordance between this classification and HY staging was weak (weighted kappa = 0.30), but was substantial (weighted kappa = 0.68) with the Non-Motor Symptoms Scale grading. CONCLUSION: Completion of NMSQuest and subsequent grading of the burden could allow the health care professional to approach the severity of NMS burden using the self completed NMSQuest in a primary care setting.

The role of functional dopamine-transporter SPECT imaging in parkinsonian syndromes, part 1.

SUMMARY: As we defeat infectious diseases and cancer, one of the greatest medical challenges facing us in the mid-21st century will be the increasing prevalence of degenerative disease. Those diseases, which affect movement and cognition, can be the most debilitating. Dysfunction of the extrapyramidal system results in increasing motor disability often manifest as tremor, bradykinesia, and rigidity. The common pathologic pathway of these diseases, collectively described as parkinsonian syndromes, such as Parkinson disease, multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, and dementia with Lewy bodies, is degeneration of the presynaptic dopaminergic pathways in the basal ganglia. Conventional MR imaging is insensitive, especially in early disease, so functional imaging has become the primary method used to differentiate a true parkinsonian syndrome from vascular parkinsonism, drug-induced changes, or essential tremor. Unusually for a modern functional imaging technique, the method most widely used in European clinics depends on SPECT and not PET. This SPECT technique (described in the first of 2 parts) commonly reports dopamine-transporter function, with decreasing striatal uptake demonstrating increasingly severe disease.

The role of functional dopamine-transporter SPECT imaging in parkinsonian syndromes, part 2.

SUMMARY: The functional imaging technique most widely used in European clinics to differentiate a true parkinsonian syndrome from vascular parkinsonism, drug-induced changes, or essential tremor is dopamine-transporter SPECT. This technique commonly reports dopamine-transporter function, with decreasing striatal uptake demonstrating increasingly severe disease. The strength of dopamine-transporter SPECT is that nigrostriatal degeneration is observed in both clinically inconclusive parkinsonism and early, even premotor, disease. In this clinical review (Part 2), we present the dopamine-transporter SPECT findings in a variety of neurodegenerative diseases, including multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, and dementia with Lewy bodies. The findings in vascular parkinsonism, drug-induced parkinsonism, and essential tremor are also described. It is hoped that this technique will be the forerunner of a range of routinely used, process-specific ligands that can identify early degenerative disease and subsequently guide disease-modifying interventions.

Long-term safety and sustained efficacy of extended-release pramipexole in early and advanced Parkinson's disease.

BACKGROUND AND PURPOSE: To assess the long-term safety and efficacy of pramipexole as a once-daily (q.d.) extended-release oral formulation in early or advanced Parkinson's disease (PD). METHODS: In two double-blind (DB) studies of early PD and one of advanced PD,active-treatment arms received pramipexole immediate release (IR) or extended release (ER), with exposure lasting up to 33 weeks. In open-label (OL) extensions that followed immediately, subjects took ER q.d. for up to 80 weeks, with dosage adjustment permitted (range 0.375-4.5 mg q.d.). RESULTS: Of 590 subjects completing an early-PD DB study, 511 entered the early-PD OL extension; 408 completed it. Reported adverse events (AEs) with incidence ≥10.0% were somnolence (15.1%), peripheral edema (11.7%) and back pain (10.6%). Of 465 subjects completing the advanced-PD DB study, 391 entered the advanced-PD OL extension; 329 completed it. Reported AEs with incidence ≥10.0%were dyskinesia (27.4%) and somnolence (13.6%). Impulse control disorders were identified by semi-structured interview in 13 subjects (1.4% of 902). In exploratory analyses, adjusted mean Unified Parkinson's Disease Rating Scale (UPDRS) PartsII + III scores (excluding ex-placebo recipients) remained substantially improved from DB baseline scores prior to pramipexole introduction, at -6.6 and -6.3 points amongst ex-DB-ER and ex-DB-IR recipients after 113 weeks of pramipexole (33 DB plus 80 OL) in early PD, and -11.5 and -9.1 after up to 113 weeks (up to 33 DB plus 80 OL) in advanced PD. CONCLUSIONS: These results support the long-term safety and efficacy of pramipexole ER in early and advanced PD. AEs were typical for dopaminergic medications, and UPDRS scores suggested sustained symptomatic benefit.

Early L-dopa, but not pramipexole, restores basal ganglia activity in partially 6-OHDA-lesioned rats.

The most appropriate time for the initiation of dopaminergic symptomatic therapy in Parkinson's disease remains debatable. It has been suggested that early correction of basal ganglia pathophysiological abnormalities may have long-term beneficial effects. To test this hypothesis, we investigated the early and delayed actions of L-dopa and pramipexole, using a delayed-start protocol of treatment. The effects of early and delayed administration of these drugs on motor response, development of dyskinesias, neurogenesis and molecular markers in basal ganglia were studied in rats with a unilateral and partial 6-hydroxydopamine-induced nigrostriatal lesion. Ten days after lesioning, rats received treatment with: a) L-dopa methyl ester (25mg/kg with 6.25mg/kg of benserazide, i.p., twice a day); b) pramipexole (0.5mg/kg, sc, twice a day) or c) saline for 4weeks. Four weeks after treatment initiation, rats from the saline group were distributed in three groups that then received the following treatments: d) L-dopa, e) pramipexole or f) saline, for 4weeks more. Three animals in each treatment arm received 5-bromo-2-deoxyuridine injections (200mg/kg) 3days before starting treatment. When compared with delayed-start L-dopa, early-start L-dopa treatment induced a lower rotational response (p<0.01), an improvement in limb akinesia (p<0.05), a lower level of dyskinesia (p<0.01) and a normalization of lesion-induced molecular changes in basal ganglia. When compared with delayed-start pramipexole, early-start pramipexole induced a higher rotational response (p<0.01), but did not improve limb akinesia, induce dyskinesia nor normalize lesion-induced molecular changes. Neither significant modifications of striatal dopamine D1-D3 receptor heteromerization nor subventricular zone neurogenesis was found after any L-dopa or pramipexole treatments. Our data support a possible restoration of basal ganglia physiological mechanisms by early-start L-dopa therapy.