Wearing Off, Dyskinesia, and the Use of Continuous Drug Delivery in Parkinson's Disease

Should continuous dopaminergic stimulation be a standard of care in advanced Parkinson's disease?

The standard of care is a term that refers to the level of care, skill, and treatment that a healthcare provider should offer to a patient based on the current scientific evidence and the level of medical knowledge available in the field. For Parkinson's disease (PD), the standard care is mostly considered to be oral treatment with dopaminergic drugs, particularly levodopa which remains the 'gold standard'. However, effective management with levodopa during the later stages of the disease becomes increasingly challenging due to the ongoing neurodegenerative process, the consequences of its pulsatile dopaminergic stimulation, and the gastrointestinal barriers to effective drug absorption. As a result, the concept of applying continuous dopaminergic stimulation has emerged with infusion therapies (continuous subcutaneous apomorphine, levodopa-carbidopa intestinal gel, and levodopa-entacapone-carbidopa intestinal gel infusion). These therapies seek to provide continuous stimulation of striatal dopamine receptors that is efficient not only in alleviating clinical symptoms, but also in delaying, reducing, and possibly preventing the onset of levodopa-related motor (fluctuations, dyskinesia) and non-motor complications; and they are also associated with clinically relevant side effects. Clinical studies and real-life experience support the notion that infusion therapies should be accepted as part of the standard of care for patients with advanced PD who have refractory, severe, and disabling motor complications that affect their quality of life. However, they should be considered based on the needs of individualized patients and the access to these advanced therapies needs to be made more accessible to the general PD population.

Tailoring Motor Fluctuation Treatment: Beyond Levodopa Dose Adjustment

Susan Fox opened this satellite symposium at the 8th European Academy of Neurology (EAN) Congress with an overview of the concept of motor fluctuations (MF) in Parkinson’s disease (PD). She emphasised that levodopa remains the gold standard therapy for PD. However, MFs are one of the critical complications of levodopa therapy that affect many patients with advancing PD and, when diagnosed, represent a challenge in patient management. Alternative options are, therefore, needed to provide continuous dopaminergic stimulation while maximising the levodopa benefit. Despite different options, Angelo Antonini showed that neurologists often prefer to adjust levodopa dose rather than add an adjunctive agent. Market research confirms that, in patients with PD, the levodopa dose is adjusted in around 80% of patients, while only 20% have adjunct therapy as a first-line option. Adjusting the levodopa dose, either by increasing or fractionating the dose, or both, remains a valid, tried-and-tested option, although it has limitations. Joaquim Ferreira presented emerging evidence from a Phase II clinical trial, suggesting a potential benefit of adding opicapone 50 mg compared with 100 mg levodopa to treat patients with PD and end-of-dose fluctuations. This symposium aimed to present the effect of opicapone with relatively low total daily doses of levodopa; an option that may not have been traditionally considered by neurologists who are used to adjusting levodopa as a first-line response.

The Comparative Efficacy of Non-ergot Dopamine Agonist and Potential Risk Factors for Motor Complications and Side Effects From NEDA Use in Early Parkinson's Disease: Evidence From Clinical Trials

Background/Objectives

Non-ergot dopamine agonist (NEDA) are recommended as the first-line treatment for patients with early Parkinson's disease (PD) because of their efficacy in treating PD motor symptoms. However, systematic evaluations of the risk of motor complications induced by NEDA and risk factors potentially associated with motor complications are still lacking.

Methods

Medline, Embase, the Cochrane Central Register of Controlled Trials, and Web of Science were searched for potentially eligible randomized controlled trials. The incidence of motor complications (dyskinesia, motor fluctuations), impulsive-compulsive behaviors and adverse events and clinical disability rating scale (UPDRS) scores were evaluated using standard meta-analytic methods. Metaregression was conducted on the incidence of motor complications (dyskinesia) with treatment duration and NEDA dose as covariates.

Results

Patients treated with NEDA had significantly lower UPDRS total scores, motor scores and activity of daily living (ADL) scores than those receiving a placebo (weighted mean difference (WMD) −4.81, 95% CI −6.57 to −3.05; WMD −4.901, 95% CI −7.03 to −2.77; WMD −1.52, 95% CI −2.19 to −0.84, respectively). Patients in the NEDA and NEDA+open Levodopa (LD) groups had lower odds for dyskinesia than patients in the LD group (OR = 0.21, 95% CI: 0.15–0.29; OR = 0.31, 95% CI 0.24–0.42, respectively). Metaregressions indicated that the mean LD dose of the NEDA group increased, and the odds of developing dyskinesia increased (p = 0.012). However, the odds of developing dyskinesia in the NEDA group were not related to treatment duration (p = 0.308). PD patients treated with NEDA or NEDA+open LD had a lower risk of wearing-off implications than those treated with LD (all p < 0.05). No significant difference was found between the NEDA and placebo groups in impulsive-compulsive behavior development (p > 0.05). Patients in the NEDA group were more likely to suffer somnolence, edema, constipation, dizziness, hallucinations, nausea and vomiting than those in the placebo or LD group.

Conclusion

NEDA therapy reduces motor symptoms and improves ADLs in early PD. The odds of developing motor complications were lower with NEDA than with LD, and dyskinesia increased with increasing LD equivalent dose and was not influenced by NEDA treatment duration. Therefore, long-term treatment with an appropriate dosage of NEDA might be more suitable than LD for early PD patients.

Registration

PROSPERO CRD42021287172.

Novel mechanistic insights towards the repositioning of alogliptin in Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disease that impairs people's lives tremendously. The development of innovative treatment modalities for PD is a significant unmet medical need. The critical function of glucagon-like peptide-1 (GLP-1) in neurodegenerative diseases has raised impetus in investigating the repositioning of a dipeptidyl peptidase IV inhibitor, alogliptin (ALO), as an effective treatment for PD. As a result, the focus of this research was to assess the effect of ALO in a rat rotenone (ROT) model of PD. For 21 days, ROT (1.5 mg/kg) was delivered subcutaneously every other day. ALO (30 mg/kg/day), delivered by gavage for 21 days, recovered motor performance and improved motor coordination in the open-field and rotarod testing. These impacts were highlighted by restoring striatal dopamine content and correcting histological changes that occurred concurrently. The ALO molecular signaling was determined by increasing the quantity of GLP-1 and the protein expression of its downstream signaling pathway, pT172-AMPK/SIRT1/PGC-1α. Furthermore, it curbed neuroinflammation via hampering HMGB1/TLR4/NLRP3 inflammasome activation and conquered striatal microglia activation. Pre-administration of dorsomorphin reversed the neuroprotective effects. In conclusion, the promising neuroprotective effect of ALO highlights the repositioning of ALO as a prospective revolutionary candidate for combating PD.

Parkinson's Disease: Personalized Pathway of Care for Device-Aided Therapies (DAT) and the Role of Continuous Objective Monitoring (COM) Using Wearable Sensors

Parkinson’s disease (PD) is a chronic, progressive neurological disorder and the second most common neurodegenerative condition. Advanced PD is complicated by erratic gastric absorption, delayed gastric emptying in turn causing medication overload, and hence the emergence of motor and non-motor fluctuations and dyskinesia, which is initially predictable and then becomes unpredictable. As the patient progresses to the advanced stage, advanced Parkinson’s disease (APD) is characterized by refractory motor and non motor fluctuations, unpredictable OFF periods, and troublesome dyskinesias. The management of APD is a complex affair. There is growing recognition that GI dysfunction is common in PD, with virtually the entire GI system (the upper and lower GI tracts) causing problems from dribbling to defecation. The management of PD should focus on personalized care addressing both motor and non-motor symptoms, ideally including not only dopamine replacement but also associated non-dopaminergic circuits, particularly focusing on noradrenergic, serotonergic, and cholinergic therapies bypassing the gastrointestinal tract (GIT) by infusion or device-aided therapies (DAT), including levodopa–carbidopa intestinal gel infusion, apomorphine subcutaneous infusion, and deep brain stimulation, which are available in many countries for the management of the advanced stage of Parkinson’s disease (APD). The PKG (KinetiGrap) can be used as a continuous objective monitoring (COM) aid, as a screening tool to help to identify advanced PD (APD) patients suitable for DAT, and can thus improve clinical outcomes.

Baseline cognitive profile is closely associated with long-term motor prognosis in newly diagnosed Parkinson's disease

OBJECTIVES

To investigate the association between cognitive function at baseline and the progression of motor disability in Parkinson's disease (PD).

METHODS

We consecutively enrolled 257 drug-naïve patients with early-stage PD (follow-up > 2 years) who underwent a detailed neuropsychological test at initial assessment. Factor analysis was conducted to yield four cognitive function factors and composite scores thereof: Factor 1 (visual memory/visuospatial), Factor 2 (verbal memory), Factor 3 (frontal/executive), and Factor 4 (attention/working memory/language). The global cognitive composite score of each patient was calculated based on these factors. Subsequently, we assessed the effect of baseline cognitive function on long-term motor outcomes, namely levodopa-induced dyskinesia (LID), wearing-off, freezing of gait (FOG), and rate of longitudinal increases in levodopa-equivalent dose (LED).

RESULTS

Cox regression analysis demonstrated that higher Factor 3 (frontal/executive) composite scores (i.e., better cognitive performance) were associated with early development of LID [hazard ratio (HR), 1.507; p = 0.003], whereas higher Factor 1 (visual memory/visuospatial) composite scores (i.e., better cognitive performance) were associated with a lower risk for FOG (HR 0.683; p = 0.017). We noted that higher global cognitive composite scores were associated with a lower risk for developing FOG (HR 0.455; p = 0.045). The linear mixed model demonstrated that higher global cognitive composite scores and better cognitive performance in visual memory/visuospatial function were associated with slower longitudinal increases in LED.

CONCLUSIONS

These findings suggest that baseline cognitive profiles have prognostic implications on several motor aspects in patients with PD.

Perivascular Spaces in the Basal Ganglia and Long-term Motor Prognosis in Newly Diagnosed Parkinson Disease

OBJECTIVE

To investigate the association between enlarged perivascular spaces (PVS) in the basal ganglia (BG-PVS) and long-term motor outcomes in Parkinson disease (PD).

METHODS

We reviewed the medical records of 248 patients with drug-naive early-stage PD (follow-up >3 years, mean age 67.44 ± 8.46 years, 130 female) who underwent brain MRI and dopamine transporter (DAT) scans at initial assessment. The number of baseline enlarged BG-PVS was counted on axial T2-weighted images. Then, patients were divided into 2 groups: a PD group with a low number (0-10) of enlarged PVS (PD-EPVS-; n = 156) and a PD group with a high number (>10) of enlarged PVS (PD-EPVS+; n = 92). We used Cox regression models to compare the levodopa-induced dyskinesia (LID)-, wearing-off-, and freezing of gait (FOG)-free times between groups. We also compared longitudinal increases in levodopa-equivalent dose per body weight between groups using a linear mixed model.

RESULTS

Patients in the PD-EPVS+ group were older (72.28 ± 6.07 years) and had greater small vessel disease burden than those in the PD-EPVS- group (64.58 ± 8.38 years). The PD-EPVS+ group exhibited more severely decreased DAT availability in all striatal subregions except the ventral striatum. The risk of FOG was higher in the PD-EPVS+ group, but the risk of LID or wearing-off was comparable between groups. The PD-EPVS+ group required higher doses of dopaminergic medications for effective symptom control compared to the PD-EPVS- group.

CONCLUSION

This study suggests that baseline enlarged BG-PVS can be an indicator of the progression of motor disability in PD.

Rotigotine Transdermal Patch for Motor and Non-motor Parkinson's Disease: A Review of 12 Years' Clinical Experience

Motor and non-motor symptoms (NMS) have a substantial effect on the health-related quality of life (QoL) of patients with Parkinson's disease (PD). Transdermal therapy has emerged as a time-tested practical treatment option, and the rotigotine patch has been used worldwide as an alternative to conventional oral treatment for PD. The efficacy of rotigotine on motor aspects of PD, as well as its safety and tolerability profile, are well-established, whereas its effects on a wide range of NMS have been described and studied but are not widely appreciated. In this review, we present our overall experience with rotigotine and its tolerability and make recommendations for its use in PD and restless legs syndrome, with a specific focus on NMS, underpinned by level 1-4 evidence. We believe that the effective use of the rotigotine transdermal patch can address motor symptoms and a wide range of NMS, improving health-related QoL for patients with PD. More specifically, the positive effects of rotigotine on non-motor fluctuations are also relevant. We also discuss the additional advantages of the transdermal application of rotigotine when oral therapy cannot be used, for instance in acute medical emergencies or nil-by-mouth or pre/post-surgical scenarios. We highlight evidence to support the use of rotigotine in selected cases (in addition to general use for motor benefit) in the context of personalised medicine.

Improving the Delivery of Levodopa in Parkinson's Disease: A Review of Approved and Emerging Therapies

Levodopa is the most effective drug for the treatment of Parkinson's disease, but its use as an oral medication is complicated by its erratic absorption, extensive metabolism and short plasma half-life. On long-term use and with disease progression, there is a high incidence of motor and non-motor complications, which remain a major clinical and research challenge. It is widely accepted that levodopa needs to be administered using formulations that result in good and consistent bioavailability and the physiologically relevant and continuous formation of dopamine in the brain to maximise its efficacy while avoiding and reversing 'wearing off' and dyskinesia. However, the physicochemical properties of levodopa along with its pharmacokinetic and pharmacodynamic profile make it difficult to deliver the drug in a manner that fulfils these criteria. In this review, we examine the problems associated with the administration of levodopa in Parkinson's disease and how the use of novel technologies and delivery devices is leading to a more consistent and sustained levodopa delivery with the aim of controlling motor function as well as non-motor symptoms.

Patterns of striatal dopamine depletion in early Parkinson disease

Objective

To investigate whether the patterns of striatal dopamine depletion on dopamine transporter (DAT) scans could provide information on the long-term prognosis in Parkinson disease (PD).

Methods

We enrolled 205 drug-naive patients with early-stage PD, who underwent18F-FP-CIT PET scans at initial assessment and received PD medications for 3 or more years. After quantifying the DAT availability in each striatal subregion, factor analysis was conducted to simplify the identification of striatal dopamine depletion patterns and to yield 4 striatal subregion factors. We assessed the effect of these factors on the development of levodopa-induced dyskinesia (LID), wearing-off, freezing of gait (FOG), and dementia during the follow-up period (6.84 ± 1.80 years).

Results

The 4 factors indicated which striatal subregions were relatively preserved: factor 1 (caudate), factor 2 (more-affected sensorimotor striatum), factor 3 (less-affected sensorimotor striatum), and factor 4 (anterior putamen). Cox regression analyses using the composite scores of these striatal subregion factors as covariates demonstrated that selective dopamine depletion in the sensorimotor striatum was associated with a higher risk for developing LID. Selective dopamine loss in the putamen, particularly in the anterior putamen, was associated with early development of wearing-off. Selective involvement of the anterior putamen was associated with a higher risk for dementia conversion. However, the patterns of striatal dopamine depletion did not affect the risk of FOG.

Conclusions

These findings suggested that the patterns of striatal dopaminergic denervation, which were estimated by the equation derived from the factor analysis, have a prognostic implication in patients with early-stage PD.

RGS Proteins as Critical Regulators of Motor Function and Their Implications in Parkinson's Disease

Parkinson disease (PD) is a devastating, largely nonfamilial, age-related disorder caused by the progressive loss of dopamine (DA) neurons in the substantia nigra pars compacta (SNc). Release of DA from these neurons into the dorsal striatum is crucial for regulating movement and their loss causes PD. Unfortunately, the mechanisms underlying SNc neurodegeneration remain unclear, and currently there is no cure for PD, only symptomatic treatments. Recently, several regulator of G protein signaling (RGS) proteins have emerged as critical modulators of PD pathogenesis and/or motor dysfunction and dyskinesia: RGSs 4, 6, 9, and 10. Striatal RGS4 has been shown to exacerbate motor symptoms of DA loss by suppressing M₄-autoreceptor-Gα _i/o signaling in striatal cholinergic interneurons. RGS6 and RGS9 are key regulators of D₂R-Gα _i/o signaling in SNc DA neurons and striatal medium spiny neurons, respectively. RGS6, expressed in human and mouse SNc DA neurons, suppresses characteristic PD hallmarks in aged mice, including SNc DA neuron loss, motor deficits, and α-synuclein accumulation. After DA depletion, RGS9 (through its inhibition of medium spiny neuron D₂R signaling) suppresses motor dysfunction induced by L-DOPA or D₂R-selective agonists. RGS10 is highly expressed in microglia, the brain's resident immune cells. Within the SNc, RGS10 may promote DA neuron survival through the upregulation of prosurvival genes and inhibition of microglial inflammatory factor expression. Thus, RGSs 4, 6, 9, and 10 are critical modulators of cell signaling pathways that promote SNc DA neuron survival and/or proper motor control. Accordingly, these RGS proteins represent novel therapeutic targets for the treatment of PD pathology. SIGNIFICANCE STATEMENT: Parkinson disease (PD), the most common movement disorder, is a progressive neurodegenerative disease characterized by substantia nigra pars compacta (SNc) dopamine (DA) neuron loss and subsequent motor deficits. Current PD therapies only target disease motor symptomology and are fraught with side effects. Therefore, researchers have begun to explore alternative therapeutic options. Regulator of G protein signaling (RGS) proteins, whether primarily expressed in SNc DA neurons (RGS6), striatal neurons (RGSs 4 and 9), or microglia (RGS10), modulate key signaling pathways important for SNc DA neuron survival and/or proper motor control. As such, RGS proteins represent novel therapeutic targets in PD.

The Use of Data from the Parkinson's KinetiGraph to Identify Potential Candidates for Device Assisted Therapies

Device-assisted therapies (DAT) benefit people with Parkinsons Disease (PwP) but many referrals for DAT are unsuitable or too late, and a screening tool to aid in identifying candidates would be helpful. This study aimed to produce such a screening tool by building a classifier that models specialist identification of suitable DAT candidates. To our knowledge, this is the first objective decision tool for managing DAT referral. Subjects were randomly assigned to either a construction set (n = 112, to train, develop, cross validate, and then evaluate the classifier’s performance) or to a test set (n = 60 to test the fully specified classifier), resulting in a sensitivity and specificity of 89% and 86.6%, respectively. The classifier’s performance was then assessed in PwP who underwent deep brain stimulation (n = 31), were managed in a non-specialist clinic (n = 81) or in PwP in the first five years from diagnosis (n = 22). The classifier identified 87%, 92%, and 100% of the candidates referred for DAT in each of the above clinical settings, respectively. Furthermore, the classifier score changed appropriately when therapeutic intervention resolved troublesome fluctuations or dyskinesia that would otherwise have required DAT. This study suggests that information from objective measurement could improve timely referral for DAT.

Chemical management of levodopa-induced dyskinesia in Parkinson's disease patients

INTRODUCTION

Levodopa-induced dyskinesias (LID) appears in more than 50% of Parkinson's disease patients after 5 years of treatment and clinicians always have to ensure that there is a balance between the beneficial effect of the treatment and the potential complications.

AREAS COVERED

In this review, the authors discuss the treatment of LID. Treatment can be divided into strategies for preventing their occurrence, modification of dopaminergic therapy, and providing more continuous dopaminergic stimulation as well as the use of nondopaminergic drugs.

EXPERT OPINION

Amantadine is currently considered the most effective drug for the treatment of LID. Several compounds developed to target adenosine, adrenergic, glutamatergic, and serotonergic receptors have shown to significantly decrease dyskinesias in animal models. However, despite promising preclinical results, translation to clinical practice remains challenging and majority of these compounds failed to decrease LID in randomized controlled trials with moderate-to-advanced parkinsonian patients. Despite promising results with nondopaminergic drugs, treatment of dyskinesias is still challenging and largely due to their side effects. Future research should focus on developing treatments that can provide continuous dopaminergic delivery throughout the day in a noninvasive manner. Studies on the impact of the early administration of long-acting formulations of levo-3,4-dihydroxy-phenylalanine on dyskinesias are also necessary.

Selegiline increases on time without exacerbation of dyskinesia in 6-hydroxydopamine-lesioned rats displaying l-Dopa-induced wearing-off and abnormal involuntary movements

3,4-Dihydroxy-l-phenylalanine (l-Dopa) remains the most effective drug for treating the motor symptoms of Parkinson's disease (PD). However, its long-term use is limited due to motor complications such as wearing-off and dyskinesia. A clinical study in PD patients with motor complications has demonstrated that selegiline, a monoamine oxidase type B inhibitor, is effective in reducing off time without worsening dyskinesia, although another study has shown worsening dyskinesia. Here, using unilateral 6-hydroxydopamine-lesioned rats showing degeneration of nigrostriatal dopaminergic neurons and l-Dopa-induced motor complications, we determined the efficacy of selegiline in controlling l-Dopa-induced motor fluctuations and exacerbated dyskinesia. Repeated administration of l-Dopa/benserazide (25/6.25 mg/kg, intraperitoneally, twice daily for 22 days) progressively shortened rotational response duration (on time) and augmented peak rotation in lesioned rats. Single subcutaneous injection of selegiline (10 mg/kg) extended l-Dopa-induced shortened on time without augmenting peak rotation. Furthermore, l-Dopa/benserazide (25/6.25 mg/kg, intraperitoneally, once daily for 7 days) progressively increased abnormal involuntary movements (l-Dopa-induced dyskinesia, LID) and peak rotation. Single subcutaneous injection of selegiline (10 mg/kg) did not exacerbate LID or alter mRNA expression of prodynorphin (PDy) and activity-regulated cytoskeleton-associated protein (Arc), both mRNAs associated with LID in the lesioned striatum. Despite undetectable plasma concentrations of selegiline and its metabolites at 24 h post-administration, these on time and LID effects did not decrease, suggesting involvement of irreversible mechanisms. Altogether, these results indicate that selegiline is effective in increasing on time without worsening dyskinesia.

Efficacy and safety of rotigotine in elderly patients with Parkinson's disease in comparison with the non-elderly: a post hoc analysis of randomized, double-blind, placebo-controlled trials

Rotigotine—a non-ergot dopamine agonist—has two advantages; it can stimulate all dopamine receptors (D1–D5) like innate dopamine, and its transdermal administration provides continuous dopaminergic stimulation. The age of the patient impacts the effect and adverse events of anti-parkinsonian treatment. We conducted a post hoc analysis on three randomized, double-blind, placebo-controlled trials performed in Japan to clarify the difference of anti-parkinsonian treatment in elderly and non-elderly patients. Data from two combination therapy trials (with levodopa) in advanced stage Parkinson’s disease patients and one monotherapy trial in early stage patients were pooled and grouped by age (non-elderly aged < 70, elderly aged 70 +). In each age group, efficacy of rotigotine was compared to placebo. In the combination therapy, total Unified Parkinson’s Disease Rating Scale Part III scores and some subtotal scores, including those for tremor, akinesia and gait disturbance, significantly improved in both elderly and non-elderly patients. Regarding safety, the incidence of total adverse event tended to be lower in elderly patients than non-elderly patients, although it was not significant. No difference was observed in maintenance dosage of rotigotine between the two groups. In conclusion, the improvement in motor symptoms and frequency of adverse events were shown to be similar in elderly and non-elderly patients with rotigotine–levodopa combination therapy. Further, there was no major difference in maintenance dosage of rotigotine between the age groups. These results suggest good tolerability of rotigotine among elderly patients.

Continuous quantitative monitoring of physical activity in Parkinson's disease patients by using wearable devices: a case-control study

The objective of this study was to explore the feasibility of using wearable devices to quantitatively measure the daily activity in patients with Parkinson's disease (PD) and to monitor medication-induced motor fluctuations. In this case-controlled study, we used monitored daily movement function in 21 patients with Parkinson's disease and 20 healthy volunteers. We analyzed the exercise types and sleep duration in the two groups and evaluated the correlation between daily movement function and age, gender, education, disease duration, Hohn-Yahr stage, UPDRS-II score, UPDRS-III score, and levodopa dose. We also determined the amount of exercise performed by PD patients at 1 h after taking levodopa and at 1 h before the next dose. The type of activity, average speed, and sleep duration in patients were significantly lower in PD patients than in healthy controls (P < 0.05). One hour after taking levodopa, patients were significantly more active than 1 h before the next dose (P < 0.05).Correlation analysis showed that age, gender, education, disease duration, Hohn-Yahr stage, UPDRS-II and UPDRS-III scores, and dosage of levodopa do not correlate with the daily movement function (P > 0.05) in patients with Parkinson's disease. In the control group, age and education were associated with daily movement function (P < 0.05), while gender was unrelated (P > 0.05). Continuous monitoring of daily activity may be useful to reveal medication-induced motor fluctuations in Parkinson's disease. The daily movement function may depend on age and education, but not on other parameters.

No time like the present - two hundred years of Parkinson's disease

Two hundred years after his seminal publication on the ‘shaking palsy’, what would James Parkinson now make of progress achieved in understanding and treating the disease that bears his name?

LSVT-BIG Improves UPDRS III Scores at 4 Weeks in Parkinson’s Disease Patients with Wearing Off: A Prospective, Open-Label Study

The efficacy of LSVT-BIG for advanced Parkinson’s disease (PD) patients with wearing off remains to be determined. Therefore, we evaluated whether LSVT-BIG improves motor disability in eight PD patients with wearing off. Unified Parkinson’s Disease Rating Scale (UPDRS) scores, daily off time, and mobility assessments were evaluated during the “on” time before and after the LSVT-BIG course. LSVT-BIG significantly improved UPDRS III scores at 4 weeks and UPDRS II scores in the “off” state at 12 weeks, with no changes in the other measures. The findings suggest that LSVT-BIG may be an effective therapy for advanced PD patients with wearing off.

Apomorphine - pharmacological properties and clinical trials in Parkinson's disease

Apomorphine is often considered an archetypal dopamine agonist used in the treatment of Parkinson's disease (PD). However, it can be clearly differentiated from most other commonly used dopamine agonists on the basis of its pharmacology and on its unique clinical profile. Like levodopa and dopamine, apomorphine acts as a potent, direct and broad spectrum dopamine agonist activating all dopamine receptor subtypes. It also has affinity for serotonin receptors, and α-adrenergic receptors. Apomorphine is usually titrated to a dose that provides an equivalent antiparkinsonian response to that provided by levodopa, and its subcutaneous delivery allows a rapid onset of action, usually within 7-10 min. The mode of apomorphine delivery impacts on its clinical profile so as to provide two very different approaches to therapy in PD. When administered as an acute subcutaneous injection, it induces reliable and rapid relief from OFF periods underscoring its utility as a rescue medication. When given as a subcutaneous infusion, it significantly improves overall daily OFF time and there is also evidence to suggest that, in those patients who replace most or all of their oral drugs with apomorphine infusion, dyskinesia may also improve. In this paper, we review the rich pharmacology of apomorphine and review its efficacy in PD based on data from clinical trials.

Non-oral Continuous Drug Delivery Techniques in Parkinson's Disease: For Whom, When, and How?

Continuous dopaminergic stimulation (CDS) has become one of the main concepts in present Parkinson's disease (PD) research. This is based on the assumption that CDS, or rather near CDS, is the normal striatal setting in a healthy individual. In PD, the degeneration of dopaminergic neurons leads to a reduced capacity to buffer dopamine, which could increase the vulnerability to a pulsatile administration of drugs. The term continuous drug delivery (CDD) describes the process of delivering drugs continuously with the aim of achieving CDS. There are three principal techniques for non-oral CDD: continuous subcutaneous apomorphine infusion CSAi), levodopa-carbidopa intestinal gel infusion (LCIGi), and transdermal rotigotine therapy. CDD has repeatedly been shown effective in the day-to-day treatment of PD patients. Although this review does not replace local guidelines regarding the use of the included non-oral CDD-based therapies, we have compiled the current base of evidence or consensus view with the intention of facilitating both the selection and the use in a clinical setting. The indications for CSAi and LCIGi are very similar and are centered around motor complications in advanced PD, whereas rotigotine has been proven effective both as a monotherapy in early PD and as an add-on to levodopa in advanced PD. Deep-brain stimulation is a relevant option for many of the patients with advanced PD, and we therefore also discuss its use in relation to the CDD-based techniques. Blinded and controlled trials have shown that non-oral CDD is an effective approach for the treatment of PD.

The Efficacy Profile of Rotigotine During the Waking Hours in Patients With Advanced Parkinson's Disease: A Post Hoc Analysis

Transdermal delivery of rotigotine maintains stable plasma concentrations for 24 hours. Three phase 3 studies of rotigotine as add-on to levodopa in advanced Parkinson's disease showed a significant reduction in “off” time from baseline to end of maintenance (EoM). However, detailed analyses over the range of a day have not yet been performed. The objective was to examine the time course of the efficacy profile of rotigotine throughout the day.

DopAmide: Novel, Water-Soluble, Slow-Release l-dihydroxyphenylalanine (l-DOPA) Precursor Moderates l-DOPA Conversion to Dopamine and Generates a Sustained Level of Dopamine at Dopaminergic Neurons

BACKGROUND

Long-term l-dihydroxyphenylalanine (l-DOPA) treatment of Parkinson's disease (PD) is associated with motor complications known as l-DOPA-induced dyskinesias (LID) and on/off fluctuations, which are linked to unsteady pulsatile dopaminergic stimulation.

AIM

The objective of this study was to improve l-DOPA treatment by slowing and stabilizing dopamine (DA) production in the brain and increasing water solubility to provide a rescue therapy for PD.

RESULTS

We synthesized l-DOPA-amide, a novel l-DOPA precursor called DopAmide. DopAmide is water soluble and, as a prodrug, requires hydrolysis prior to decarboxylation by the aromatic l-amino acid decarboxylase (EC 4.1.1.28; AAAD). In the 6-OH-dopamine (6-OHDA)-lesioned rats, DopAmide maintained steady rotations for up to 4 h compared with 2 h by l-DOPA, suggesting that this rate-limiting step generated a sustained level of DA at dopaminergic neurons. Pharmacokinetic studies showed elimination half-life of l-DOPA in the plasma after DopAmide treatment of t1/2 = 4.1 h, significantly longer than t1/2 = 2.9 h after treatment with l-DOPA, consistent with the 6-OHDA results.

CONCLUSIONS

The slow conversion of DopAmide to l-DOPA provides a sustained level of DA in the dopaminergic cells, shown by the long 6-OHDA steady rotations. The water solubility and improved bioavailability may help reduce medication frequency associated with l-DOPA treatment of PD. Sustained levels of DA might lower the super-sensitization of DA signaling and potentially attenuate l-DOPA adverse effects.

Glial activation is associated with l-DOPA induced dyskinesia and blocked by a nitric oxide synthase inhibitor in a rat model of Parkinson's disease

l-3, 4-dihydroxyphenylalanine (L-DOPA) is the most effective treatment for Parkinson's disease but can induce debilitating abnormal involuntary movements (dyskinesia). Here we show that the development of L-DOPA-induced dyskinesia in the rat is accompanied by upregulation of an inflammatory cascade involving nitric oxide. Male Wistar rats sustained unilateral injections of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle. After three weeks animals started to receive daily treatment with L-DOPA (30 mg/kg plus benserazide 7.5 mg/kg, for 21 days), combined with an inhibitor of neuronal NOS (7-nitroindazole, 7-NI, 30 mg/kg/day) or vehicle (saline-PEG 50%). All animals treated with L-DOPA and vehicle developed abnormal involuntary movements, and this effect was prevented by 7-NI. L-DOPA-treated dyskinetic animals exhibited an increased striatal and pallidal expression of glial fibrillary acidic protein (GFAP) in reactive astrocytes, an increased number of CD11b-positive microglial cells with activated morphology, and the rise of cells positive for inducible nitric oxide-synthase immunoreactivity (iNOS). All these indexes of glial activation were prevented by 7-NI co-administration. These findings provide evidence that the development of L-DOPA-induced dyskinesia in the rat is associated with activation of glial cells that promote inflammatory responses. The dramatic effect of 7-NI in preventing this glial response points to an involvement of nitric oxide. Moreover, the results suggest that the NOS inhibitor prevents dyskinesia at least in part via inhibition of glial cell activation and iNOS expression. Our observations indicate nitric oxide synthase inhibitors as a therapeutic strategy for preventing neuroinflammatory and glial components of dyskinesia pathogenesis in Parkinson's disease.