Association between voriconazole-induced visual hallucination and dopamine in an analysis of the food and drug administration (FDA) adverse event reporting system database.

Voriconazole is a second-generation azole used to treat serious fungal infections. Visual hallucinations constitute a representative adverse event caused by voriconazole. However, its mechanism of action remains unclear. In patients with schizophrenia or Parkinson's disease, the frequency of visual hallucinations is associated with brain dopamine levels. This study investigated the frequency of visual hallucinations in patients treated with voriconazole alone or in combination with dopaminergic medicines or dopamine antagonists, using data collected from the Food and Drug Administration Adverse event Reporting System (FAERS). The frequency of visual hallucinations with voriconazole alone and in combination with a dopaminergic medicine (levodopa) or dopamine antagonists (risperidone and chlorpromazine) was compared using data from the FAERS between 2004 and 2023, using the reporting odds ratio (ROR) with relevant 95% confidence intervals (CI). The reference group comprised patients who had been administered voriconazole without dopaminergic medication or dopamine antagonists. Of the patients, 22,839, 90,810, 109,757, 6,435, 20, 83, and 26, respectively were treated with voriconazole, levodopa, risperidone, chlorpromazine, voriconazole plus levodopa, voriconazole plus risperidone, and voriconazole plus chlorpromazine. The occurrence of visual hallucinations increased when used in combination with levodopa (ROR = 12.302, 95% CI = 3.587-42.183). No increase in incidence was associated with the concomitant use of dopamine antagonists (risperidone, ROR = 1.721, 95% CI = 0.421-7.030; chlorpromazine, ROR = none, 95% CI = none). Dopaminergic medicine may increase the risk of visual hallucinations in patients treated with voriconazole. Whether voriconazole positively modulates dopamine production warrants further investigation using a translational research approach.

The effects of L-DOPA on gait abnormalities in a unilateral 6-OHDA rat model of Parkinson's disease.

Parkinson's Disease (PD) is a neurodegenerative movement disorder characterized by dopamine (DA) cell loss in the substantia nigra pars compacta (SNc). As PD progresses, patients display disruptions in gait such as changes in posture, bradykinesia, and shortened stride. DA replacement via L-DOPA alleviates many PD symptoms, though its effects on gait are not well demonstrated. This study aimed to assess the relationship between DA lesion, gait, and deficit-induced reversal with L-DOPA. To do so, Sprague-Dawley rats (N = 25, 14 males, 11 females) received unilateral medial forebrain bundle (MFB) DA lesions with 6-hydroxydopamine (6-OHDA). An automated gait analysis system assessed spatiotemporal gait parameters pre- and post-lesion, and after various doses of L-DOPA (0, 3, or 6 mg/kg; s.c.). The forepaw adjusting steps (FAS) test was implemented to evaluate lesion efficacy while the abnormal involuntary movements (AIMs) scale monitored the emergence of L-DOPA-induced dyskinesia (LID). High performance liquid chromatography (HPLC) assessed changes in brain monoamines on account of lesion and treatment. Results revealed lesion-induced impairments in gait, inclusive of max-contact area and step-sequence alterations that were not reversible with L-DOPA. However, the emergence of AIMs were observed at higher doses. Post-mortem, 6-OHDA lesions induced a loss of striatal DA and norepinephrine (NE), while prefrontal cortex (PFC) displayed noticeable reduction in NE but not DA. Our findings indicate that hemiparkinsonian rats display measurable gait disturbances similar to PD patients that are not rescued by DA replacement. Furthermore, non-DA mechanisms such as attention-related NE in PFC may contribute to altered gait and may constitute a novel target for its treatment.

Exploring Cardiovascular Autonomic Function before and after Chronic Deep Brain Stimulation in Parkinson's Disease.

BACKGROUND: Blood pressure control in Parkinson's disease (PD) under subthalamic deep brain stimulation (STN-DBS) is influenced by several intertwined aspects, including autonomic failure and levodopa treatment. OBJECTIVE: To evaluate the effect of chronic STN-DBS, levodopa, and their combination on cardiovascular autonomic functions in PD. METHODS: We performed cardiovascular reflex tests (CRTs) before and 6-months after STN-DBS surgery in 20 PD patients (pre-DBS vs. post-DBS). CRTs were executed without and with medication (med-OFF vs. med-ON). RESULTS: CRT results and occurrence of neurogenic orthostatic hypotension (OH) did not differ between pre- and post-DBS studies in med-OFF condition. After levodopa intake, the BP decrease during HUTT was significantly greater compared to med-OFF, both at pre-DBS and post-DBS evaluation. Levodopa-induced OH was documented in 25% and 5% of patients in pre-DBS/med-ON and post-DBS/med-ON study. CONCLUSION: Chronic stimulation did not influence cardiovascular responses, while levodopa exerts a relevant hypotensive effect. The proportion of patients presenting levodopa-induced OH decreases after STN-DBS surgery.

The prevalence of non-troublesome dyskinesia in Parkinson's disease.

INTRODUCTION: Levodopa-induced dyskinesia is a common complication of long-term treatment of Parkinson's disease (PD), but its impact on daily activities is somewhat controversial. This study investigated the prevalence and severity of dyskinesia, particularly non-troublesome dyskinesia, to provide insights into its significance for long-term PD management. METHODS: We reviewed electronic medical records of 2571 PD patients, who had been followed up at Seoul National University Hospital and were seen between January 2016 and June 2017. Dyskinesia severity had been assessed during follow-up and was recorded with the highest score by considering its impact on functioning (0 = no dyskinesia, 1 = minimal with patient unaware, 2 = mild disability, 3 = moderate disability, 4 = severe disability). RESULTS: The prevalence of dyskinesia increased progressively with longer PD duration; 8.2% in the group with disease duration of 0-5 years, 40.7% for 6-10 years, 66.0% for 11-15 years, 74.6% for 16-20 years, and 83.2% for 21 years or more. The prevalence of dyskinesia scores ≥2 also increased with disease duration, with rates of 6.3% for 0-5 years, 31.9% for 6-10 years, 54.8% for 11-15 years, 62.9% for 16-20 years and 73.7% for 21 or more years. CONCLUSION: Despite the increasing prevalence and severity of dyskinesia with longer PD duration, the study found that less than non-troublesome dyskinesia remained at approximately 26.3% even after more than 21 years of disease duration. These findings suggest that dyskinesia may not be troublesome for many PD patients even in long-term.

Delayed levodopa-responsive parkinsonism following acute midbrain injury.

Acute midbrain injury may cause both hyperkinetic movement disorders and parkinsonism. The temporal interval between the insult and the emergence of hyperkinetic disorders can last years. A delayed appearance of parkinsonism, on the other hand, was rarely described. We present three cases of male patients (50-, 58- and 28-year-old) who developed levodopa-responsive parkinsonism 20, 8 and two years, respectively, after acute brain insult involving the midbrain. Insults included subcortical intracerebral hemorrhage dissecting into the midbrain, embolic basilar occlusion and trauma. A fluorodopa scan, performed in two cases, revealed reduced striatal uptake. All individuals improved on low doses of levodopa and developed motor fluctuations shortly after levodopa was introduced. We conclude that delayed, levodopa-responsive parkinsonism following midbrain injury should be recognized in the relevant clinical setup. Possible mechanisms include age-related loss of dopaminergic neurons superimposed on acute injury and secondary neurodegeneration.

Antagonism of metabotropic glutamate receptor type 5 prevents levodopa-induced dyskinesia development in a male rat model of Parkinson's disease: Electrophysiological evidence.

Levodopa-induced dyskinesia (LID) is a common complication in patients with advanced Parkinson's disease (PD) undergoing treatment with levodopa. Glutamate receptor antagonists can suppress LID; however, the underlying mechanisms remain unclear. Here, we aimed to evaluate the effect of 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)pyridine (MTEP), a metabotropic glutamate receptor 5 (mGluR5) antagonist, on dyskinesia. We recorded the neuronal activity of the entopeduncular nucleus and examined responses to cortical electric stimulation in the control group (n = 6) and three groups of rats (male PD model). Saline was intraperitoneally administered to dopamine lesioned (DL) rats (n = 6), levodopa/benserazide (L/B) was administered to LID rats (n = 8), and L/B combined with MTEP was administered to MTEP rats (n = 6) twice daily for 14 days. We administered L/B to LID and MTEP rats 48 h after the final administration of MTEP to examine the chronic effect of MTEP. The control and DL groups did not have LID. The MTEP group had less LID than the LID group (p < .01) on day 1 and day 18. The control group had a typical triphasic pattern consisting of early excitation (early-Ex), inhibition, and late excitation (late-Ex). However, the inhibition phase disappeared, was partially observed, and was fully suppressed in the DL, LID, and MTEP groups, respectively. The cortico-striato-entopeduncular pathway is important in the pathophysiology of LID. mGluR5 antagonism suppresses LID progression by preventing physiological changes in the cortico-striato-entopeduncular pathway. Future studies are required to validate these results.

Machine-learning model for the prediction of acute orthostatic hypotension after levodopa administration.

BACKGROUND: Levodopa could induce orthostatic hypotension (OH) in Parkinson's disease (PD) patients. Accurate prediction of acute OH post levodopa (AOHPL) is important for rational drug use in PD patients. Here, we develop and validate a prediction model of AOHPL to facilitate physicians in identifying patients at higher probability of developing AOHPL. METHODS: The study involved 497 PD inpatients who underwent a levodopa challenge test (LCT) and the supine-to-standing test (STS) four times during LCT. Patients were divided into two groups based on whether OH occurred during levodopa effectiveness (AOHPL) or not (non-AOHPL). The dataset was randomly split into training (80%) and independent test data (20%). Several models were trained and compared for discrimination between AOHPL and non-AOHPL. Final model was evaluated on independent test data. Shapley additive explanations (SHAP) values were employed to reveal how variables explain specific predictions for given observations in the independent test data. RESULTS: We included 180 PD patients without AOHPL and 194 PD patients with AOHPL to develop and validate predictive models. Random Forest was selected as our final model as its leave-one-out cross validation performance [AUC_ROC 0.776, accuracy 73.6%, sensitivity 71.6%, specificity 75.7%] outperformed other models. The most crucial features in this predictive model were the maximal SBP drop and DBP drop of STS before medication (ΔSBP/ΔDBP). We achieved a prediction accuracy of 72% on independent test data. ΔSBP, ΔDBP, and standing mean artery pressure were the top three variables that contributed most to the predictions across all individual observations in the independent test data. CONCLUSIONS: The validated classifier could serve as a valuable tool for clinicians, offering the probability of a patient developing AOHPL at an early stage. This supports clinical decision-making, potentially enhancing the quality of life for PD patients.

Association of dopamine receptor D3 polymorphism with Levodopa-induced Dyskinesia: A study on Parkinson's disease patients from India.

INTRODUCTION: Levodopa-induced dyskinesia (LID) is a debilitating motor feature in a subset of patients with Parkinson's disease (PD) after prolonged therapeutic administration of levodopa. Preliminary animal and human studies are suggestive of a key role of dopamine type 3 (D3) receptor polymorphism (Ser9Gly; rs6280) in LID. Its contribution to development of LID among Indian PD patients has remained relatively unexplored and merits further investigation. METHODS AND MATERIALS: 200 well-characterised PD patients (100 without LID and 100 with LID) and 100 age-matched healthy controls were recruited from the outpatient department of Institute of Neurosciences Kolkata. MDS-UPDRS (Unified Parkinson's Disease Rating Scale from International Movement Disorder Society) Part III and AIMS (abnormal involuntary movement scale) were performed for estimation of severity of motor features and LID respectively in the ON state of the disease. Participants were analysed for the presence of Ser9Gly single nucleotide variant (SNV) (rs6280) by polymerase chain reaction followed by restriction fragment length polymorphism techniques. RESULTS: The frequency of AA genotype (serine type) was more frequently present in PD patients with LID compared to PD patients without LID (50 % vs 28 %; P = 0.002; OR = 2.57, 95 % CI: 1.43 - 4.62). The abnormal involuntary movement scale score was significantly higher in PD patients with AA genotype compared to carriers of glycine allele (AG + GG) (4.08 ± 3.35; P = 0.002). CONCLUSION: We observed a significant association of serine type SNV (rs6280) in D3 receptor gene in a cohort of PD patients with LID from India. More severe motor severity was found in patients with glycine substitution of the same SNV. The current study emphasised the role of D3 receptor in the pathogenesis of LID.

Effectiveness and safety of different catechol-o-methyl transferase inhibitors for patients with parkinson's disease: Systematic review and network meta-analysis.

BACKGROUND: Levodopa treatment requires the addition of other drugs, such as catechol-O-methyl transferase (COMT) inhibitors, to alleviate motor fluctuations in advanced parkinson's disease (PD). However, the optimal strategy, including the type and dose of COMT inhibitors remains unknown. This systematic review and network meta-analysis aimed to assess the efficacy and safety of different COMT inhibitors and for treating PD patients. METHODS: PubMed, Embase, Cochrane Library and Web of Science were screened up to November 20, 2022. Randomized controlled trials (RCTs) of COMT inhibitors (entacapone, opicapone, tolcapone) for PD patients were included. Eligible outcomes were total ON-time, rate of ON-time >1 h, total daily dose of levodopa therapy, mean change from baseline to final follow up in Unified Parkinson's Disease Rating Scale (UPDRS) part III scores, adverse events and dyskinesia. Network meta-analyses integrated direct and indirect evidence with placebo as a common comparator. RESULTS: We identified 18 studies with 7564 patients. Opicapone, entacapone, and tolcapone could increase total ON-time when compared with placebo. However, opicapone (25 mg, MD 4.0, 95%CrI: 1.1-7.5) and opicapone (50 mg, MD 5.1, 95%CrI: 2.2-8.7) statistically significant increase the total ON-time. opicapone and entacapone could increase the rate of ON-time >1 h when compared with placebo. Only opicapone (5 mg) showed no statistically significant with placebo (OR 1.4, 95%CrI: 0.74-2.4). We found that opicapone (50 mg, SURCA, 0.796) is the best option compared with other treatments. TOL (200 mg) was ranked highest in the rank probability test for total daily dose of levodopa therapy, followed by OPI (50 mg), TOL (400 mg) and TOL (100 mg) in order. SUCRA rankings identified TOL (200 mg) as the most likely therapy for increasing adverse events (SUCRA 27.19%), followed by TOL (400 mg, SUCRA 27.20%) and OPI (5 mg, SUCRA 30.81%). The SUCRA probabilities were 91.6%, 75.2%, 67.9%, 59.3%, 45.6%, 41.1%, 35.1%, 24.6% and 9.4% for PLA, TOL (400 mg), ENT (100 mg), ENT (200 mg), OPI (5 mg), TOL (100 mg), OPI (25 mg), OPI (50 mg), and TOL (200 mg) respectively. CONCLUSION: In conclusion, opicapone (50 mg) may be a better choice for treatment PD when compared with other COMT inhibitors.

Levodopa-Carbidopa-Entacapone Intestinal Gel in Advanced Parkinson Disease: A Multicenter Real-Life Experience.

BACKGROUND: For Parkinson disease (PD) patients who have been diagnosed with advanced disease that can no longer be effectively controlled with optimized oral or transdermal medications, a range of device-aided therapies (DAT) are available, comprising either deep brain stimulation or infusion therapies providing continuous dopaminergic stimulation. Levodopa-entacapone-carbidopa intestinal gel (LECIG) infusion is the latest DAT for advanced PD (APD) that was approved in Romania in 2021. STUDY QUESTION: What is the experience to date in real-world clinical practice in Romania regarding the efficacy and tolerability of LECIG in APD? STUDY DESIGN: A retrospective evaluation of 74 APD patients treated with LECIG at 12 specialized APD centers in Romania. MEASURES AND OUTCOMES: Demographic data and various clinical parameters were recorded, including Mini Mental State Evaluation score or Montreal Cognitive Assessment Test score. Levodopa-equivalent daily dose and the administered doses of levodopa and other PD medications were evaluated at baseline and after starting LECIG treatment. The efficacy of LECIG in reducing daily hours of off time, motor fluctuations, and dyskinesias were assessed. Any percutaneous endoscopic gastrojejunostomy system or device complications after starting LECIG treatment were noted. RESULTS: At baseline, patients were taking oral levodopa for a mean of 5.3 times per day, with a high proportion also taking concomitant add-on therapies (dopamine agonists, 86%, monoamine oxidase type-B inhibitors, 53%; catechol-O-methyltransferase inhibitors, 64%). LECIG treatment significantly reduced daily off time versus baseline from 5.7 h/d to 1.7 hours per day ( P < 0.01). Duration and severity of dyskinesias was also significantly reduced versus baseline, and improvements were observed in Hoehn and Yahr Scale scores. LECIG treatment also allowed a significant reduction in the use of concomitant oral medications. CONCLUSIONS: These findings suggest that LECIG treatment is an effective DAT option in APD that can simplify the treatment regimen.

Effects of supplementary Da Dingfeng Zhu therapy on patients with Parkinson's disease of liver-kidney yin deficiency pattern.

BACKGROUND: This study aimed to verify whether the combined use of Da Dingfengzhu and Western medicine in treating Parkinson's disease (PD) can lead to therapeutic efficacy and symptom alleviation, thereby achieving a complementary and synergistic effect. METHODS: In this study, 158 patients were initially enrolled, with 116 eligible patients randomly divided into a control and an observation group. The control group received levodopa/benserazide and pramipexole, while the observation group received Da Dingfengzhu combined with levodopa/benserazide and pramipexole for 12 weeks. Baseline patient characteristics, adverse reactions, and blood samples were collected at baseline and 12 weeks post-treatment. The Unified Parkinson's Disease Rating Scale (UPDRS) was used to assess symptom severity at baseline, four weeks into treatment, and 12 weeks post-treatment. RESULTS: Adverse reactions during treatment were similar in both groups, suggesting that the combined therapy in the observation group did not increase adverse effects. Both groups showed improvements in UPDRS scores, with the observation group displaying more significant symptom alleviation at 4 and 12 weeks. Moreover, the observation group exhibited more pronounced increases in serum neurotrophic factor-3 and dopamine levels and greater reductions in oxidative stress and inflammatory response markers. CONCLUSION: In conclusion, the combination of Da Dingfengzhu with levodopa/benserazide and pramipexole for treating PD shows significant clinical potential and is worthy of broader application.

Serotonin as a biomarker of toxin-induced Parkinsonism.

BACKGROUND: Loss of dopaminergic neurons underlies the motor symptoms of Parkinson's disease (PD). However stereotypical PD symptoms only manifest after approximately 80% of dopamine neurons have died making dopamine-related motor phenotypes unreliable markers of the earlier stages of the disease. There are other non-motor symptoms, such as depression, that may present decades before motor symptoms. METHODS: Because serotonin is implicated in depression, here we use niche, fast electrochemistry paired with mathematical modelling and machine learning to, for the first time, robustly evaluate serotonin neurochemistry in vivo in real time in a toxicological model of Parkinsonism, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). RESULTS: Mice treated with acute MPTP had lower concentrations of in vivo, evoked and ambient serotonin in the hippocampus, consistent with the clinical comorbidity of depression with PD. These mice did not chemically respond to SSRI, as strongly as control animals did, following the clinical literature showing that antidepressant success during PD is highly variable. Following L-DOPA administration, using a novel machine learning analysis tool, we observed a dynamic shift from evoked serotonin release in the hippocampus to dopamine release. We hypothesize that this finding shows, in real time, that serotonergic neurons uptake L-DOPA and produce dopamine at the expense of serotonin, supporting the significant clinical correlation between L-DOPA and depression. Finally, we found that this post L-DOPA dopamine release was less regulated, staying in the synapse for longer. This finding is perhaps due to lack of autoreceptor control and may provide a ground from which to study L-DOPA induced dyskinesia. CONCLUSIONS: These results validate key prior hypotheses about the roles of serotonin during PD and open an avenue to study to potentially improve therapeutics for levodopa-induced dyskinesia and depression.

Buspirone and Zolmitriptan Combination for Dyskinesia: A Randomized, Controlled, Crossover Study.

BACKGROUND: Preclinical evidence suggests that co-administration of the 5-HT1A agonist buspirone and the 5-HT1B/1D agonist zolmitriptan act synergistically to reduce dyskinesia to a greater extent than that achieved by either drug alone. OBJECTIVES: Assess the therapeutic potential of a fixed-dose buspirone and zolmitriptan combination in Parkinson's disease (PD) patients with levodopa-induced dyskinesia. METHODS: Single-center, randomized, placebo-controlled, two-way crossover study (NCT02439203) of a fixed-dose buspirone/zolmitriptan regimen (10/1.25 mg three times a day) in 30 patients with PD experiencing at least moderately disabling peak-effect dyskinesia. RESULTS: Seven days of treatment with buspirone/zolmitriptan added to levodopa significantly reduced dyskinesia as assessed by Abnormal Involuntary Movement Scale scores versus placebo (mean treatment effect vs. placebo: -4.2 [-6.1, -2.3]) without significantly worsening Unified Parkinson's Disease Rating Scale (UPDRS) Part III (ON) scores (mean treatment effect vs. placebo: 0.6 [-0.1, 1.3]). No serious adverse events were reported. CONCLUSIONS: In this proof-of-concept study, addition of buspirone/zolmitriptan to the patients' PD medication regimen significantly reduced dyskinesia severity without worsening motor function. © 2024 International Parkinson and Movement Disorder Society.

Sodium nitroprusside enhances stepping test performance and increases medium spiny neurons responsiveness to cortical inputs in a rat model of Levodopa-induced dyskinesias.

Levodopa (L-DOPA) is the classical gold standard treatment for Parkinson's disease. However, its chronic administration can lead to the development of L-DOPA-induced dyskinesias (LIDs). Dysregulation of the nitric oxide-cyclic guanosine monophosphate pathway in striatal networks has been linked to deficits in corticostriatal transmission in LIDs. This study investigated the effects of the nitric oxide (NO) donor sodium nitroprusside (SNP) on behavioural and electrophysiological outcomes in sham-operated and 6-hydroxydopamine-lesioned rats chronically treated with vehicle or L-DOPA, respectively. In sham-operated animals, systemic administration of SNP increased the spike probability of putative striatal medium spiny neurons (MSNs) in response to electrical stimulation of the primary motor cortex. In 6-hydroxydopamine-lesioned animals, SNP improved the stepping test performance without exacerbating abnormal involuntary movements. Additionally, SNP significantly increased the responsiveness of putative striatal MSNs in the dyskinetic striatum. These findings highlight the critical role of the NO signalling pathway in facilitating the responsiveness of striatal MSNs in both the intact and dyskinetic striata. The study suggests that SNP has the potential to enhance L-DOPA's effects in the stepping test without exacerbating abnormal involuntary movements, thereby offering new possibilities for optimizing Parkinson's disease therapy. In conclusion, this study highlights the involvement of the NO signalling pathway in the pathophysiology of LIDs.

Levodopa-Entacapone-Carbidopa Intestinal Gel Treatment in Advanced Parkinson's Disease: A Single-Center Study of 30 Patients.

BACKGROUND: Levodopa-entacapone-carbidopa intestinal gel (LECIG) is a novel device assisted treatment option for advanced Parkinson's disease (PD). It has been available in Finland since 2020. There is paucity of scientific studies considering LECIG treatment in clinical practice. OBJECTIVES: Objectives of this study were to evaluate the changes in medication, adverse events and early discontinuations of LECIG treatment in real life clinical practice. METHODS: The records of 30 consecutive patients, who received LECIG between years 2020 and 2022 in Helsinki University Hospital, were retrospectively analyzed. Data considering changes in medication, discontinuations, and adverse events during the first six months of LECIG treatment was collected. RESULTS: Mean levodopa equivalent daily dose (LEDD) rose significantly between baseline before LECIG and six months with treatment (1230 mg vs. 1570 mg, P = 0.001). Three patients were discarded during nasojejunal tube test phase and seven discontinued the treatment during six-month follow-up. Most common reasons for discontinuation were difficulty in finding suitable infusion rate and neuropsychiatric problems. Safety issues encountered were similar to those reported with levodopa-carbidopa intestinal gel (LCIG) treatment. One case of rhabdomyolysis due to severe dyskinesia during LECIG treatment was observed. Patients were satisfied with the small size of the pump system. CONCLUSIONS: LEDD seems to increase during the first months of LECIG treatment. When compared to studies on LCIG, safety profile of LECIG appears similar, but early discontinuation rate is higher than expected. However, long-term studies are lacking. Only clear advantage to LCIG appears to be the smaller LECIG pump size.

Impulse control behaviors and apathy commonly co-occur in de novo Parkinson's disease and predict the incidence of levodopa-induced dyskinesia.

OBJECTIVE: Impulse control behaviors (ICBs) and apathy are believed to represent opposite motivational expressions of the same behavioral spectrum involving hypo- and hyperdopaminergic status, but this has been recently debated. Our study aims to estimate the co-occurrence of ICBs and apathy in early Parkinson's disease (PD) and to determine whether this complex neuropsychiatric condition is an important marker of PD prognoses. METHODS: Neuropsychiatric symptoms, clinical data, neuroimaging results, and demographic data from de novo PD patients were obtained from the Parkinson's Progression Markers Initiative, a prospective, multicenter, observational cohort. The clinical characteristics of ICBs co-occurring with apathy and their prevalence were analyzed. We compared the prognoses of the different groups during the 8-year follow-up. Multivariate Cox regression analysis was conducted to predict the development of levodopa-induced dyskinesia (LID) using baseline neuropsychiatric symptoms. RESULTS: A total of 422 PD patients and 195 healthy controls (HCs) were included. In brief, 87 (20.6 %) de novo PD patients and 37 (19.0 %) HCs had ICBs at baseline. Among them, 23 (26.4 %) de novo PD patients and 3 (8.1 %) HCs had clinical symptoms of both ICBs and apathy. The ICBs and apathy group had more severe non-motor symptoms than the isolated ICBs group. Cox regression analysis demonstrated that the co-occurrence of ICBs and apathy was a risk factor for LID development (HR 2.229, 95 % CI 1.209 to 4.110, p = 0.010). CONCLUSIONS: Co-occurrence of ICBs and apathy is common in patients with early PD and may help to identify the risk of LID development.

Using artificial intelligence to identify drugs for repurposing to treat l-DOPA-induced dyskinesia.

Repurposing regulatory agency-approved molecules, with proven safety in humans, is an attractive option for developing new treatments for disease. We identified and assessed the efficacy of 3 drugs predicted by an in silico screen as having the potential to treat l-DOPA-induced dyskinesia (LID) in Parkinson's disease. We analysed ∼1.3 million Medline abstracts using natural language processing and ranked 3539 existing drugs based on predicted ability to reduce LID. 3 drugs from the top 5% of the 3539 candidates; lorcaserin, acamprosate and ganaxolone, were prioritized for preclinical testing based on i) having a novel mechanism of action, ii) having not been previously validated for the treatment of LID, iii) being blood-brain-barrier penetrant and orally bioavailable and iv) being clinical trial ready. We assessed the efficacy of acamprosate, ganaxolone and lorcaserin in a rodent model of l-DOPA-induced hyperactivity, with lorcaserin affording a 58% reduction in rotational asymmetry (P < 0.05) compared to vehicle. Acamprosate and ganaxolone failed to demonstrate efficacy. Lorcaserin, a 5HT2C agonist, was then further tested in MPTP lesioned dyskinetic macaques where it afforded an 82% reduction in LID (P < 0.05), unfortunately accompanied by a significant increase in parkinsonian disability. In conclusion, although our data do not support the repurposing of lorcaserin, acamprosate or ganaxolone per se for LID, we demonstrate value of an in silico approach to identify candidate molecules which, in combination with an in vivo screen, can facilitate clinical development decisions. The present study adds to a growing literature in support of this paradigm shifting approach in the repurposing pipeline.

Enhancement of Haloperidol-Induced Catalepsy by GPR143, an L-Dopa Receptor, in Striatal Cholinergic Interneurons.

Dopamine neurons play crucial roles in pleasure, reward, memory, learning, and fine motor skills and their dysfunction is associated with various neuropsychiatric diseases. Dopamine receptors are the main target of treatment for neurologic and psychiatric disorders. Antipsychotics that antagonize the dopamine D2 receptor (DRD2) are used to alleviate the symptoms of these disorders but may also sometimes cause disabling side effects such as parkinsonism (catalepsy in rodents). Here we show that GPR143, a G-protein-coupled receptor for L-3,4-dihydroxyphenylalanine (L-DOPA), expressed in striatal cholinergic interneurons enhances the DRD2-mediated side effects of haloperidol, an antipsychotic agent. Haloperidol-induced catalepsy was attenuated in male Gpr143 gene-deficient (Gpr143-/y ) mice compared with wild-type (Wt) mice. Reducing the endogenous release of L-DOPA and preventing interactions between GPR143 and DRD2 suppressed the haloperidol-induced catalepsy in Wt mice but not Gpr143-/y mice. The phenotypic defect in Gpr143-/y mice was mimicked in cholinergic interneuron-specific Gpr143-/y (Chat-cre;Gpr143flox/y ) mice. Administration of haloperidol increased the phosphorylation of ribosomal protein S6 at Ser240/244 in the dorsolateral striatum of Wt mice but not Chat-cre;Gpr143flox/y mice. In Chinese hamster ovary cells stably expressing DRD2, co-expression of GPR143 increased cell surface expression level of DRD2, and L-DOPA application further enhanced the DRD2 surface expression. Shorter pauses in cholinergic interneuron firing activity were observed after intrastriatal stimulation in striatal slice preparations from Chat-cre;Gpr143flox/y mice compared with those from Wt mice. Together, these findings provide evidence that GPR143 regulates DRD2 function in cholinergic interneurons and may be involved in parkinsonism induced by antipsychotic drugs.

Reduced Plasma Levodopa Fluctuations with More Frequent Administration of a Novel Carbidopa/Levodopa Functionally Scored Tablet.

Levodopa/carbidopa remains the gold standard for treating Parkinson disease (PD), but chronic pulsatile administration contributes to motor complications. This Phase 1 study used a new immediate-release (IR) formulation of carbidopa/levodopa 25/100 mg that is functionally scored for easy and precise splitting to evaluate the effects on levodopa plasma variability when smaller doses are taken more frequently. These functionally scored tablets were shown to be bioequivalent to carbidopa/levodopa 25-/100-mg IR generic reference tablets. Twenty-two healthy volunteers received a whole tablet every 4 hours versus half of the tablet every 2 hours. Plasma levodopa fluctuations were significantly reduced with half-tablets dosed every 2 hours, with a 44% reduction in peaks (P < .0001). While drug exposure did not differ, parameters that underlie motor response variations, including mean peak-to-trough difference and variance, were 51% and 56% less, respectively, with more frequent dosing (both P ≤ .0024). Safety and tolerability of both regimens were similar. In conclusion, more frequent administration of half-tablets of the new functionally scored IR formulation safely provided more constant levodopa levels than whole tablets dosed less often. This tablet technology could facilitate the benefits of more physiologic dopamine replenishment in patients with PD, particularly those with reduced manual dexterity.