Ropinirole reverses the effects of neuroinflammation, and cellular demise by downregulating the MARK4-NFκß signaling system in Alzheimer's disease.

Ropinirole (ROP) is a dopamine agonist that can cross the blood-brain barrier (BBB), which is crucial for drugs targeting neurological conditions like Alzheimer's disease (AD). The rationale for the current research is to investigate the potential of ROP as an inhibitor of Microtubule affinity regulating kinase 4 (MARK4)-NFκß in neurodegenerative diseases, specifically AD. The interaction between ROP and MARK4-NFκß holds significant promise in the realm of drug discovery and therapeutic interventions for diseases like AD. Molecular docking and biophysical characterization demonstrate how ROP effectively hinders MARK4 activity, offering detailed insights into their molecular interactions. The present research also investigates the biological aspect of MARK4 shows promise in treating AD, with neuroinflammation playing a crucial role in the disease's progression. Aß42 and ROP were co-administered directly into the cells for the establishment of the AD model. We confirmed that ROP can inhibit the path of MARK4 activity, as evidenced by biophysical characterization, and can enhance the cell viability, lowers the expression of MARK4, decrease the rate of oxidative stress, and attenuate the expression of NFκß, leading to reduced neuronal apoptosis in an in vitro-induced Aß model. Overall, this research provides valuable mechanistic insights into the neuroprotective potential of ROP and its ability to target the MARK4-NFκß pathway.

Dopamine agonists in restless leg syndrome treatment and their effects on sleep parameters: A systematic review and meta-analysis.

BACKGROUND: Dopamine agonists (DAs) constitute the standard therapeutic scheme for restless leg syndrome (RLS) because they have been proven to be effective. However, DAs may change sleep parameters, thus having adverse effects on patient condition. This meta-analysis clarified the effects of DAs used in RLS treatment on the sleep architecture. METHODS: PubMed, Embase, and Cochrane Central databases were searched for randomized control trials (RCT) (up to October 2023) that discussed the effects of DAs on sleep architecture in patients with RLS. A meta-analysis employing a random-effects model was conducted. The patients were divided into subgroups according to individual DAs and treatment duration (1 day or ≥4 weeks). RESULTS: Thirteen eligible randomized placebo-controlled trials were included in the assessment. The effects of three DAs (i.e., pramipexole, ropinirole, and rotigotine) on rapid eye movement (REM) sleep, slow-wave sleep (SWS), and sleep efficiency (SE) were analyzed. Overall, pramipexole significantly improved SE but decreased the percentage of REM sleep among treated patients. Ropinirole also enhanced SE compared with the placebo group. Rotigotine did not affect SE and REM sleep. Subgroup analysis found that pramipexole used for 1 day and ≥4 weeks significantly diminished the percentage of REM sleep. Ropinirole used for 1 day showed similar REM sleep patterns. Finally, none of the three DAs affected SWS. CONCLUSIONS: This meta-analysis demonstrated that DAs significantly affect sleep parameters.

Intranasal and intravenous apomorphine outperform ropinirole ocular drops for induction of emesis in dogs within ten minutes: a randomized, controlled clinical trial.

OBJECTIVE: The primary goal was to compare the efficacy of administration of apomorphine (APO) administered by intranasal (IN), transconjunctival (TC), SC and IV routes with ropinirole eye drops for induction of emesis in dogs with a secondary goal to evaluate the time of emesis as well as difficulty in administration. ANIMALS: 125 client-owned dogs. METHODS: Dogs were randomly enrolled between October 1, 2021, and March 30, 2022, into groups of 25: IV APO, IN APO, TC APO, SC APO, and ropinirole eye drops. The IV, SC, and TC groups were dosed at 0.03 mg/kg, the IN group was dosed at 0.06 mg/kg, and the ropinirole group was dosed according to manufacturer guidelines. Data collected included success rate of emesis within 600 seconds, time to emesis, time to administer, and difficulty score. Results were compared to IV with P values and CIs being adjusted for multiple comparisons. RESULTS: Emesis was successful within 600 seconds using IV APO in 22 of 25 dogs. By comparison, IN APO induced emesis in 18 of 25 dogs (P = .63). Ropinirole (14/25), SC APO (6/25), and TC APO (4/25) were significantly less successful (P = .047, P = < .001, and P < 0.001, respectively). When emesis was successful, it occurred most rapidly with TC APO, followed by IN APO and then ropinirole. It was most difficult to administer IV APO and TC APO. CLINICAL RELEVANCE: Similar to IV APO, IN APO was a rapid, easy, and effective method of inducing emesis in dogs and should be considered when IV administration is not possible. Ropinirole was easy to administer but successfully induced emesis less reliably within a 10-minute timeframe. APO administered TC using the commercially compounded injectable formulation was ineffective.

The Interplay of Mitochondrial Bioenergetics and Dopamine Agonists as an Effective Disease-Modifying Therapy for Parkinson's Disease.

Parkinson's disease (PD) is a progressive neurological ailment with a slower rate of advancement that is more common in older adults. The biggest risk factor for PD is getting older, and those over 60 have an exponentially higher incidence of this condition. The failure of the mitochondrial electron chain, changes in the dynamics of the mitochondria, and abnormalities in calcium and ion homeostasis are all symptoms of Parkinson's disease (PD). Increased mitochondrial reactive oxygen species (mROS) and an energy deficit are linked to these alterations. Levodopa (L-DOPA) is a medication that is typically used to treat most PD patients, but because of its negative effects, additional medications have been created utilizing L-DOPA as the parent molecule. Ergot and non-ergot derivatives make up most PD medications. PD is successfully managed with the use of dopamine agonists (DA). To get around the motor issues produced by L-DOPA, these dopamine derivatives can directly excite DA receptors in the postsynaptic membrane. In the past 10 years, two non-ergoline DA with strong binding properties for the dopamine D2 receptor (D2R) and a preference for the dopamine D3 receptor (D3R) subtype, ropinirole, and pramipexole (PPx) have been developed for the treatment of PD. This review covers the most recent research on the efficacy and safety of non-ergot drugs like ropinirole and PPx as supplementary therapy to DOPA for the treatment of PD.

Can 3D Printed Tablets Be Bioequivalent and How to Test It: A PBPK Model Based Virtual Bioequivalence Study for Ropinirole Modified Release Tablets.

As the field of personalized dosing develops, the pharmaceutical manufacturing industry needs to offer flexibility in terms of tailoring the drug release and strength to the individual patient's needs. One of the promising tools which have such capacity is 3D printing technology. However, manufacturing small batches of drugs for each patient might lead to huge test burden, including the need to conduct bioequivalence trials of formulations to support the change of equipment or strength. In this paper we demonstrate how to use 3D printing in conjunction with virtual bioequivalence trials based on physiologically based pharmacokinetic (PBPK) modeling. For this purpose, we developed 3D printed ropinirole formulations and tested their bioequivalence with the reference product Polpix. The Simcyp simulator and previously developed ropinirole PBPK model were used for the clinical trial simulations. The Weibull-fitted dissolution profiles of test and reference formulations were used as inputs for the model. The virtual bioequivalence trials were run using parallel design. The study power of 80% was reached using 125 individuals. The study demonstrated how to use PBPK modeling in conjunction with 3D printing to test the virtual bioequivalence of newly developed formulations. This virtual experiment demonstrated the bioequivalence of one of the newly developed formulations with a reference product available on a market.

Demotion of canonical/non-canonical inflammasome and pyroptosis alleviates ischemia/reperfusion-induced acute kidney injury: Novel role of the D2/D3 receptor agonist ropinirole.

Ropinirole used to treat Parkinson's disease highly targets the dopaminergic receptor D3 over the D2 receptor but although both are expressed in the kidneys the ropinirole potential to treat kidney injury provoked by ischemia/reperfusion (I/R) is undraped. We investigated whether ropinirole can alleviate renal I/R by studying its anti-inflammatory, antioxidant, and anti-pyroptotic effects targeting its aptitude to inhibit the High-mobility group box 1/Toll-like receptor 4/Nuclear factor-kappa B (HMGB1/TLR4/NF-κB) cue and the canonical/non-canonical NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome trajectories. Herein, bilateral I/R surgery was induced in animals to be either untreated or treated with ropinirole for three days after the insult. Ropinirole successfully improved the histopathological picture and renal function which was confirmed by reducing cystatin C and the standard parameters creatinine and blood urea nitrogen (BUN). Ropinirole achieved this through its anti-inflammatory capacity mediated by reducing the HMGB1/TLR4 axis and inactivating NF-κB, which are upstream regulators of the NLRP3 pathway. As a result, the injurious inflammasome markers (NLRP3, apoptosis-associated speck-like protein (ASC), active caspase-1) and their target cytokines interleukin-1 beta (IL-1ß) and IL-18 were decreased. Ropinirole also reduced the pyroptotic cell death markers caspase-11 and gasdermin-D. Furthermore, ropinirole by replenishing antioxidants and decreasing malondialdehyde helped to reduce oxidative stress in the kidneys. The docking findings confirmed that ropinirole highly binds to the dopaminergic D3 receptor more than to the D2 receptor. In conclusion, ropinirole has the potential to be a reno-therapeutic treatment against I/R insult by abating the inflammatory NLRP3 inflammasome signal, pyroptosis, and oxidative stress.

Fabricating Polymer/Surfactant/Cyclodextrin Hybrid Particles for Possible Nose-to-Brain Delivery of Ropinirole Hydrochloride: In Vitro and Ex Vivo Evaluation.

Ropinirole is a non-ergolinic dopamine agonist used to manage Parkinson's disease and it is characterized by poor oral bioavailability. This study aimed to design and develop advanced drug delivery systems composed of poloxamer 407, a non-ionic surfactant (Tween 80), and cyclodextrins (methyl-ß-CD or hydroxy-propyl-ß-CD) for possible brain targeting of ropinirole after nasal administration for the treatment of Parkinson's disease. The hybrid systems were formed by the thin-film hydration method, followed by an extensive physicochemical and morphological characterization. The in vitro cytotoxicity of the systems on HEK293 cell lines was also tested. In vitro release and ex vivo mucosal permeation of ropinirole were assessed using Franz cells at 34 °C and with phosphate buffer solution at pH 5.6 in the donor compartment, simulating the conditions of the nasal cavity. The results indicated that the diffusion-controlled drug release exhibited a progressive increase throughout the experiment, while a proof-of-concept experiment on ex vivo permeation through rabbit nasal mucosa revealed a better performance of the prepared hybrid systems in comparison to ropinirole solution. The encouraging results in drug release and mucosal permeation indicate that these hybrid systems can serve as attractive platforms for effective and targeted nose-to-brain delivery of ropinirole with a possible application in Parkinson's disease. Further ex vivo and in vivo studies to support the results of the present work are ongoing.

Ropinirole for the Treatment of Hyperprolactinemia: A Dose-Escalation Study of Efficacy and Tolerability.

CONTEXT: Treatment of hyperprolactinemia with ergoline dopamine agonists (DAs) can be complicated by intolerance and resistance. OBJECTIVE: This study examines the efficacy and tolerability of the nonergot DA ropinirole for the long-term treatment of hyperprolactinemia. METHODS: Twelve hyperprolactinemic women were treated with ropinirole in a 6-month, open-label, dose-escalation trial; 7 of the 12 continued treatment in an extension study for up to 17 months. Ropinirole doses were uptitrated to achieve normal prolactin (PRL) levels, restore menses, and eliminate galactorrhea. RESULTS: Two of the 12 participants were DA naive; 6 of 12 were ergot DA intolerant; and 1 of 12 had known ergot DA resistance. Baseline PRL levels were 126.2 ± 41.4 ng/mL (SEM). Ropinirole was uptitrated from 0.125 to 0.25 mg/h to a median total daily dose (TDD) of 2 mg/d (1-4 mg/d [interquartile range]). PRL normalization was achieved in 50% of the participants (5 with microadenomas and 1 with idiopathic hyperprolactinemia) at a median effective TDD of 1 mg/d. Of the patients achieving PRL normalization, 83% were ergot DA intolerant. A persistent partial biochemical response (PRL reduction >50% from baseline) was achieved in 17% of the participants. During treatment, menses resumed in 67% of amenorrheic patients; galactorrhea resolved in 67%. Mild adverse effects were reported in 92% of participants; however, ropinirole was not discontinued because of intolerance even among the 50% of individuals with a prior history of ergot DA intolerance and resultant medication discontinuation. CONCLUSION: These data demonstrate the efficacy and tolerability of ropinirole for the treatment of hyperprolactinemia in patients with microprolactinomas and idiopathic hyperprolactinemia and suggest ropinirole may represent a novel therapeutic alternative for treating hyperprolactinemic disorders in patients with ergot DA intolerance.

Impulse control disorders in Parkinson's disease: a retrospective analysis of 1824 patients in a 12-year period.

OBJECTIVE: This study aims to clinically evaluate the impulse control disorders (ICDs) encountered in treating Parkinson's disease. METHOD: This is a retrospective analysis between 2010 and 2022. We retrieved the medical records of all patients diagnosed with idiopathic Parkinson's disease. The demographic and clinical findings were recorded. ICDs constituted a specific item in the examination, and each one (compulsive shopping, compulsive eating, pathological gambling, hypersexuality, punding, dopamine dysregulation syndrome, and hobbyism) was noted separately. RESULTS: In the study period, we identified 1824 patients (56.2% men, n = 1025). The mean age was 70.5 ± 11.9 years. In the cohort, 128 (7%) patients with Parkinson's disease had one or more ICDs. The ICDs were compulsive shopping, punding/hobbyism, compulsive eating, hypersexuality, pathological gambling, and dopamine dysregulation syndrome. When we compared patients with and without ICDs, patients with ICDs were younger (p ≤ 0.001), and the men/women ratio was higher in this group with ICDs. Although the mean daily pramipexole dose was higher in patients with ICDs, mean daily long-acting pramipexole dose was only 1.4 ± 0.92 mg/day. CONCLUSION: The significant findings in this study were (i) the lower frequency of ICDs (7%); (ii) the common occurrence of compulsive shopping, punding/hobbyism, and compulsive eating; and (iii) the development of ICDs under relatively lower doses of pramipexole. We suggest that ICDs in Parkinson's disease should be associated with a personal trait with dopamine agonists, and potential electrophysiological or genetic markers of this trait warrant further analysis to avoid treatment in these patients.

Impulse control disorders in Parkinson's disease patients treated with pramipexole and ropinirole: a systematic review and meta-analysis.

BACKGROUND: This analysis is the first systematic review and meta-analysis assessing occurrences of ICD in PD patients treated with oral DAs: ropinirole (ROP) and pramipexole (PRX). This study compares the two oral DAs to a transdermal patch, rotigotine (RTG). METHODS: We performed an extensive systematic search for eligible studies from PubMed, Embase, Cochrane Library, and Google Scholar. The data was analyzed by various software, including EndNote, Rayyan, PRISM, and RevMan. Two studies incorporating 658 patients collectively were assessed. RESULTS: This meta-analysis shows a significant correlation between the usage of PRX (25.3%) or ROP (21.8%) and the development of ICD in PD patients. Compared to the transdermal patch, RTG, PRX was found to have a significant relative risk (P < 0.0001) of 3.46 (95% CI 2.07-5.76), and ROP was found to have a significant relative risk (P < 0.0001) of 2.98 (95% CI 1.77-5.02). The data collected shows RTG is approximately three times less likely to cause ICDs than oral PRX and ROP. CONCLUSION: The present investigation provides insight into ICD occurrences with PRX, ROP, and RTG to allow physicians to make more informed decisions on risk versus reward when deciding how to treat a PD patient with these drugs. However, related to various disclosed limitations, our conclusion cannot provide definitive practice protocols.

Induced pluripotent stem cells-based disease modeling, drug screening, clinical trials, and reverse translational research for amyotrophic lateral sclerosis.

It has been more than 10 years since the hopes for disease modeling and drug discovery using induced pluripotent stem cell (iPSC) technology boomed. Recently, clinical trials have been conducted with drugs identified using this technology, and some promising results have been reported. For amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease, several groups have identified candidate drugs, ezogabine (retigabine), bosutinib, and ropinirole, using iPSCs-based drug discovery, and clinical trials using these drugs have been conducted, yielding interesting results. In our previous study, an iPSCs-based drug repurposing approach was utilized to show the potential of ropinirole hydrochloride (ROPI) in reducing ALS-specific pathological phenotypes. Recently, a phase 1/2a trial was conducted to investigate the effects of ropinirole on ALS further. This double-blind, randomized, placebo-controlled study confirmed the safety and tolerability of and provided evidence of its ability to delay disease progression and prolong the time to respiratory failure in ALS patients. Furthermore, in the reverse translational research, in vitro characterization of patient-derived iPSCs-motor neurons (MNs) mimicked the therapeutic effects of ROPI in vivo, suggesting the potential application of this technology to the precision medicine of ALS. Interestingly, RNA-seq data showed that ROPI treatment suppressed the sterol regulatory element-binding protein 2-dependent cholesterol biosynthesis pathway. Therefore, this pathway may be involved in the therapeutic effect of ROPI on ALS. The possibility that this pathway may be involved in the therapeutic effect of ALS was demonstrated. Finally, new future strategies for ALS using iPSCs technology will be discussed in this paper.

Neuroprotective effect of ropinirole against Aß1-42 -induced neurochemical perturbations and cognitive impairments in a rodent model.

The primary objective of this study was to investigate the protective effects of ropinirole (ROP) medication given for an extended period following the induction of cognitive decline, oxidative stress, and deterioration of mitochondria in a Wistar rat model by Aß1-42 . This study aimed to examine the neuroprotective efficacy of ROP in a stereotaxis model of AD. The Wistar rats were randomly assigned into four groups. Group I was considered as a sham, group II served as Aß-infusion alone, Group III was Aß1-42 + ROP (5 mg/kg/i.p.), and Group IV was Aß1-42 + ROP (10 mg/kg/i.p.). Our research revealed that ROP (10 mg/kg, b.wt.) attenuates the cognitive deficits caused by Aß1-42 -infused, which also correlates with the barnes maze, where (10 mg/kg, b.w.t.) shows significant improvement in spatial learning and memory. At the same time, ROP was rescued from oxidative damage, decreased lipid peroxidation rates, and inhibited acetylcholinesterase activity caused, demonstrating antioxidant benefits. In addition, a higher dose of ROP restored mitochondrial membrane potential in Aß1-42 rats. Furthermore, histopathological examination showed that ROP treatment reduced neuronal loss, especially in the hippocampus. We conclude that ROP's protective effects in reducing oxidative stress and modulating mitochondrial function might have a propensity in AD pathogenesis.

Side effects based network construction and drug repositioning of ropinirole as a potential molecule for Alzheimer's disease: an in-silico, in-vitro, and in-vivo study.

Alzheimer's disease (AD) is the leading cause of dementia in older adults. Drug repositioning is a process of finding new therapeutic applications for existing drugs. One of the methods in drug repositioning is to use the side-effect profile of a drug to identify a new therapeutic indication. The drugs with similar side-effects may act on similar biological targets and could affect the same biochemical process. In this study, we explored the Food and Drug Administration-approved drugs using PROMISCUOUS database to find those that have adverse effects profile comparable with the ligands being studied or used to treat AD. Here, we found that the ropinirole, a dopamine receptor agonist, shared a maximum number of side-effects with the drugs proven beneficial for treating AD. Furthermore, molecular modelling demonstrated that ropinirole exhibited strong binding affinity (-9.313 kcal/mol) and best ligand efficiency (0.49) with sigma-1 receptor. Here, we observed that the quaternary amino group of ropinirole is essential for binding with sigma-1 receptor. Molecular dynamic simulation indicated that the movement of the carboxy-terminal helices (α4/α5) could play a major role in the receptor's physiological functions. The neurotoxicity induced by Aß25-35 in SH-SY5Y cells was reduced by ropinirole at concentrations 10, 30, and 50 µM. The effect on spatial learning and memory was examined in mice with Aß25-35 induced memory deficit using the radial arm maze. Ropinirole (10 and 20 mg/kg) significantly improved the short and long-term memories in the radial arm maze test. Our results suggest that ropinirole has the potential to be repositioned for AD treatment.Communicated by Ramaswamy H. Sarma.

A Randomized, Open Label, Exploratory Trial Comparing Efficacy of Amantadine and Ropinirole in Restless Legs Syndrome.

Objective Amantadine has both anti-glutamatergic and dopaminergic action and may improve restless legs syndrome (RLS). We compared the efficacy and adverse-effect profile of amantadine and ropinirole in RLS. Methods In this randomized, open-label, 12-week flexible-dose exploratory study, RLS patients with international RLS study group severity scale score (IRLSS) > 10 were randomized to receive either amantadine(100-300mg/day) or ropinirole (0.5-2mg/day). Drug dose was increased until week-6 if IRLSS failed to improve by ≥10% of previous visit score. IRLSS change from baseline at week-12 was the primary outcome. Secondary outcomes included change in RLS-related quality of life (RLS-QOL) and insomnia severity index (ISI), along with clinical-global-impression of change/improvement (CGI-I), and proportion of patients with adverse-effects and resulting discontinuation. Results Twenty-four patients received amantadine and 22 received ropinirole. Both groups had a significant effect for visit*treatment arm (F (2.19,68.15) =4.35;P = 0.01). With a similar baseline IRLSS, both intention-to-treat (ITT) and per-protocol analyses revealed comparable IRLSS until week-8, with ropinirole appearing superior from week-10 to week-12 (week-12 IRLSS, amantadine vs ropinirole:17.0 ± 5.7 vs 9.0 ± 4.4;P < 0.001). ITT analysis at week-12 showed comparable proportion of responders (≥10% IRLSS reduction) in both groups (P = 0.10). Both drugs improved sleep and QOL, but week-12 scores favoured ropinirole [(ISI:14.4 ± 5.7 vs 9.4 ± 4.5; P = 0.001) ;(RLS-QOL:70.4 ± 17.9 vs 86.5 ± 9.8; P = 0.005)]. CGI-I at week-12 favoured ropinirole (Mann-Whitney U = 35.50, S. E = 23.05;P = 0.01). Four patients in amantadine and two in ropinirole group developed adverse effects, with resulting discontinuation in two patients on amantadine. Conclusions The present study reports equivalent reduction in RLS symptoms with both amantadine and ropinirole until week-8, with the latter being superior from week-10 onwards. Ropinirole was better tolerated.

Comparative efficacy and safety of six non-ergot dopamine-receptor agonists in early Parkinson's disease: a systematic review and network meta-analysis.

Background: Non-ergot dopamine agonists (NEDAs) have been used as monotherapy or as an adjunctive therapy to levodopa for many years. Novel long-acting formulations of NEDAs including pramipexole extended-release (ER), ropinirole prolonged-release (PR), and rotigotine transdermal patch have been developed. However, there is no strong evidence that a given NEDA is more potent than another. We performed a systematic review and network meta-analysis to evaluate the efficacy, tolerability and safety of six commonly used NEDAs in early Parkinson's disease (PD). Methods: Six NEDAs including piribedil, rotigotine transdermal patch, pramipexole immediate-release (IR)/ER, and ropinirole IR/PR were investigated. The efficacy outcomes including Unified Parkinson's Disease Rating Scale activities in daily life (UPDRS-II), motor function (UPDRS-III), and their subtotal (UPDRS-II + III), tolerability and safety outcomes were analyzed. Results: A total of 20 RCTs (5,355 patients) were included in the current study. The result indicated that compared with placebo, all six investigated drugs had statistically significant differences in the improvement of UPDRS-II, UPDRS-III, and UPDRS-II + III (except ropinirole PR in UPDRS-II). There were no statistically significant differences between six NEDAs for the UPDRS-II and UPDRS-III. For UPDRS-II + III, the improvement of ropinirole IR/PR and piribedil were higher than that of rotigotine transdermal patch, and piribedil was higher than that of pramipexole IR. The surface under the cumulative ranking curve (SUCRA) indicated that piribedil resulted in best improvement in UPDRS-II and UPDRS-III (0.717 and 0.861, respectively). For UPDRS-II + III, piribedil and ropinirole PR exhibited similar improvement and both had high rates (0.858 and 0.878, respectively). Furthermore, piribedil performed better as monotherapy, ranking first in the improvement of UPDRS-II, III, and II + III (0.922, 0.960, and 0.941, separately). With regard to tolerability, there was a significant increase in overall withdrawals with pramipexole ER (0.937). In addition, the incidence of adverse reaction of ropinirole IR was relatively high (nausea: 0.678; somnolence: 0.752; dizziness: 0.758; fatigue: 0.890). Conclusions: In this systematic review and network meta-analysis of six NEDAs, piribedil exhibited better efficacy, especially as monotherapy, and ropinirole IR was associated with a higher incidence of adverse events in patients with early PD.

Phase 1/2a clinical trial in ALS with ropinirole, a drug candidate identified by iPSC drug discovery.

iPSC-based drug discovery led to a phase 1/2a trial of ropinirole in ALS. 20 participants with sporadic ALS received ropinirole or placebo for 24 weeks in the double-blind period to evaluate safety, tolerability, and therapeutic effects. Adverse events were similar in both groups. During the double-blind period, muscle strength and daily activity were maintained, but a decline in the ALSFRS-R, which assesses the functional status of ALS patients, was not different from that in the placebo group. However, in the open-label extension period, the ropinirole group showed significant suppression of ALSFRS-R decline and an additional 27.9 weeks of disease-progression-free survival. iPSC-derived motor neurons from participants showed dopamine D2 receptor expression and a potential involvement of the SREBP2-cholesterol pathway in therapeutic effects. Lipid peroxide represents a clinical surrogate marker to assess disease progression and drug efficacy. Limitations include small sample sizes and high attrition rates in the open-label extension period, requiring further validation.

Metabolism of ropinirole is mediated by several canine CYP enzymes.

BACKGROUND: Ropinirole has been shown to provoke vomiting in dogs by activating the dopamine D2-like receptors in the chemoreceptor trigger zone. In humans, ropinirole is metabolized primarily by CYP1A2. Corresponding dog CYP1A2 is known to be a polymorphic enzyme which can cause variation in pharmacokinetics of compounds metabolised via this enzyme. OBJECTIVES: The aim of this study was to understand metabolic clearance of ropinirole in dogs, the enzymes involved in ropinirole metabolism and specially to estimate whether the clearance can be sensitive towards the polymorphism of canine CYP1A2. METHODS: Metabolism of ropinirole was studied in dog hepatocytes and specific recombinant canine CYP isoforms. Metabolite identification and metabolite formation were evaluated using LC-mass spectrometry. RESULTS: Ropinirole was moderately stable in dog hepatocytes with Clint of 16.3 µL/min/million cells, and the metabolites detected were 7-hydroxy ropinirole and respective glucuronide conjugate as well as despropyl ropinirole. Regarding recombinant CYPs either 7-hydroxy ropinirole, despropyl ropinirole or both were detected for each CYP isoform studied. The highest rates of metabolite formation were observed in CYP2B11, CYP2C21, CYP2D15, CYP1A2 and CYP1A1. Fluvoxamine, a fairly selective human CYP1A/CYP2C19 inhibitor inhibited ropinirole metabolism by CYP1A1, CYP1A2, CYP2B11, CYP2C21 and CYP2D15 for 65.8%-100% showing no selectivity towards canine CYP isoforms. CONCLUSIONS: Although human metabolism of ropinirole is mainly mediated through CYP1A2, the current study shows that several canine CYP isoforms are able to contribute to the clearance of ropinirole in dogs. This is expected to reduce a possible impact of canine CYP1A2 polymorphism on ropinirole pharmacokinetics.

The complex molecular pharmacology of the dopamine D2 receptor: Implications for pramipexole, ropinirole, and rotigotine.

With L-DOPA, dopamine agonists such as pramipexole, ropinirole and rotigotine constitute key therapeutic options for the management of motor symptoms of Parkinson's disease. These compounds exert their beneficial effect on motor behaviours by activating dopamine D2-class receptors and thereby compensating for the declining dopaminergic transmission in the dorsal striatum. Despite a strong similarity in their mechanism of action, these three dopamine agonists present distinct clinical profiles, putatively underpinned by differences in their pharmacological properties. In this context, this review aims at contributing to close the gap between clinical observations and data from molecular neuropharmacology by exploring the properties of pramipexole, ropinirole and rotigotine from both the clinical and molecular perspectives. Indeed, this review first summarizes and compares the clinical features of these three dopamine agonists, and then explores their binding profiles at the different dopamine receptor subtypes. Moreover, the signalling profiles of pramipexole, ropinirole and rotigotine at the D2 receptor are recapitulated, with a focus on biased signalling and the potential therapeutic implications. Overall, this review aims at providing a unifying framework of interpretation for both clinicians and fundamental pharmacologists interested in a deep understanding of the pharmacological properties of pramipexole, ropinirole and rotigotine.

Dopamine Agonist Cotreatment Alters Neuroplasticity and Pharmacology of Levodopa-Induced Dyskinesia.

BACKGROUND: Current models of levodopa (L-dopa)-induced dyskinesia (LID) are obtained by treating dopamine-depleted animals with L-dopa. However, patients with LID receive combination therapies that often include dopamine agonists. OBJECTIVE: Using 6-hydroxydopamine-lesioned rats as a model, we aimed to establish whether an adjunct treatment with the D2/3 agonist ropinirole impacts on patterns of LID-related neuroplasticity and drug responses. METHODS: Different regimens of L-dopa monotreatment and L-dopa-ropinirole cotreatment were compared using measures of hypokinesia and dyskinesia. Striatal expression of ∆FosB and angiogenesis markers were studied immunohistochemically. Antidyskinetic effects of different drug categories were investigated in parallel groups of rats receiving either L-dopa monotreatment or L-dopa combined with ropinirole. RESULTS: We defined chronic regimens of L-dopa monotreatment and L-dopa-ropinirole cotreatment inducing overall similar abnormal involuntary movement scores. Compared with the monotreatment group, animals receiving the L-dopa-ropinirole combination exhibited an overall lower striatal expression of ∆FosB with a distinctive compartmental distribution. The expression of angiogenesis markers and blood-brain barrier hyperpermeability was markedly reduced after L-dopa-ropinirole cotreatment compared with L-dopa monotreatment. Moreover, significant group differences were detected upon examining the response to candidate antidyskinetic drugs. In particular, compounds modulating D1 receptor signaling had a stronger effect in the L-dopa-only group, whereas both amantadine and the selective NMDA antagonist MK801 produced a markedly larger antidyskinetic effect in L-dopa-ropinirole cotreated animals. CONCLUSIONS: Cotreatment with ropinirole altered LID-related neuroplasticity and pharmacological response profiles. The impact of adjuvant dopamine agonist treatment should be taken into consideration when investigating LID mechanisms and candidate interventions in both clinical and experimental settings. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.