Pramipexole reduces the prevalence of fatigue in patients with Parkinson's disease

My History in Juntendo University

With my retirement as a professor, I would like to review my 47-year history of studying and working at Juntendo University. I was admitted to Juntendo University School of Medicine in 1976, and after graduation I joined the Department of Neurology in 1982, where Professor Hirotaro Narabayashi was the founding chairman. I became particularly interested in movement disorders and neurophysiology. The second chairman, Professor Yoshikuni Mizuno, established an American-style neurology training system. From 1992 to 1994, I studied electrophysiology at the University of Calgary in Canada, and my family and I enjoyed life in Canada very much. In 2000, I moved to Juntendo Izu-Nagaoka Hospital, now renamed Juntendo Shizuoka Hospital. I instructed young neurologists to write case reports in English. Owing to this achievement, the third chairman, Professor Nobutaka Hattori, recommended me to be a recipient of Alumni Scientific Award and to become a professor of neurology in 2009. I also became an executive officer of the Asian and Oceanian Section of the International Parkinson and Movement Disorders Society from 2015 to 2019. In 2017, I was appointed as the dean of the Faculty of Health Science and Nursing. I devoted myself to improving the nursing education and then I received the Best Professor Award twice. The level of the faculty improved, so that all the students were able to pass the National Nursing Examination consistently. In conclusion, I thank all my colleagues, faculty members, and family for letting me have valuable experiences and memories in Juntendo University.

Fatigue in hypokinetic, hyperkinetic, and functional movement disorders

The emerging science of fatigue has soundly endorsed the need for its unified definition, shared terminology and increased recognition in neurological illnesses. Nevertheless, the real impact of fatigue remains under-recognized. Fatigue describes a sense of tiredness, lack of energy or need for increased effort often perceived as overwhelming, pervasive, and disabling. It is a common feature of chronic medical conditions and neurological diseases, including Parkinson's disease (PD) and other hypokinetic, hyperkinetic, and functional movement disorders (FMD). While there is solid evidence for the burden of fatigue in PD, knowledge of fatigue in other movement disorders (MDS) is still limited. Lack of consensus definition, rigorous measures and the high prevalence of potential confounders such as apathy, depression and sleepiness are the main obstacles in studying fatigue in MDS. This review of the prevalence, impact, and clinical correlates of fatigue in common MDS summarizes current hypotheses for the pathophysiological mechanisms underlying fatigue and gives a brief overview of treatment options. Fatigue is a prevalent, disabling, primary non-motor symptom (NMS) in MDS, including atypical and secondary parkinsonisms, dystonia, essential tremor (ET) and a hallmark feature of FMD. We report the hypothesis that fatigue is a perceptual disorder of the sensorimotor system. Given the relevance of this burdensome symptom, fatigue deserves greater clinical and research attention to better understand its manifestation and pathophysiology and to improve diagnosis and treatment.

Classics in Chemical Neuroscience: Pramipexole

Pramipexole was first manufactured by Pharmacia and Upjohn in July 1997 under the United States brand names of Mirapex and Mirapex ER. Pramipexole is classified as a nonergoline aminobenzothiazole compound that selectively agonizes the dopamine D₂-like receptor subfamily, which includes the D₂, D₃, and D₄ receptor subtypes. Pramipexole is a unique compound in its therapeutic potential because it has D₃-preferring properties. The D₃ receptor target has implications in both motor and psychiatric symptoms of Parkinson's disease, restless leg syndrome, and bipolar and unipolar depression. Currently, pramipexole is approved to treat signs and symptoms of idiopathic Parkinson's disease and moderate to severe symptoms of primary restless leg syndrome. Parkinson's disease is characterized by tremor, bradykinesia, rigidity, gait disorders, and a disturbance of posture due to a decrease in dopamine stores in the substantia nigra with the consequent presence of Lewy bodies. Restless leg syndrome is a neurologic sensorimotor disorder characterized by a compelling urge to move the body/limb to relieve this uncomfortable sensation. In this Review, we will discuss the synthesis, drug metabolism, pharmacology, adverse effects, history, and the importance of pramipexole to neuroscience and describe its role in therapy.

Direct synthesis of 2-substituted benzimidazoles via dehydrogenative coupling of aromatic-diamine and primary alcohol catalyzed by a Co complex

A Co(ii) complex was synthesized and used as catalyst to synthesize a series of 2-substituted benzimidazoles with o-phenylenediamines and primary alcohol as the substrates under mild reaction conditions.

Fatigue in Parkinson's disease: A systematic review and meta-analysis

We conducted a systematic review and meta-analysis aimed at establishing robust prevalence estimates and identifying clinical correlates of fatigue in PD. From 2,459 titles and abstracts, we selected 44 relevant studies (n = 7427 patients). Overall, the meta-analysis showed a prevalence of fatigue of 50% in PD. This prevalence estimate, however, was significantly moderated by study heterogeneity in measurement scales and cut-off thresholds. In contrast, demographic features, disease severity, cognitive impairment, and depression did not moderate prevalence estimates. Moreover, fatigue prevalence did not differ between de novo and treated PD patients. Compared to nonfatigued patients, fatigued patients had sligthly higher age (1.44 years), disease duration (0.93 years), l-dopa equivalent daily dose (50.89 units), UPDRS-III (4.99 points), and H & Y (0.33 points), as well as risk of comorbid depression (risk ratio = 1.89) and had a little lower MMSE score (-0.66 points). Fatigue was moderately associated with apathy (Hedges' g = 0.55), anxiety (Hedges' g = 0.67), daytime somnolence (Hedges' g = 0.43), sleep disturbances (Hedges' g = 0.66), and poorer quality of life (Hedges' g = 1.23). Our analyses suggest that fatigue is a frequent, independent nonmotor symptom in PD appearing early and persisting throughout the disease course, and that establishing uniform diagnostic criteria for PD-related fatigue is critical. In addition, several nonmotor symptoms appear to be associated with fatigue and negatively impact quality of life. Pharmacological and nonpharmacological interventions targeting fatigue and associated symptoms may improve quality of life in patients with PD. © 2018 International Parkinson and Movement Disorder Society.

Does fatigue in Parkinson's disease correlate with autonomic nervous system dysfunction?

BACKGROUND

Despite its negative impact on quality of life, fatigue in Parkinson's disease (PD) remains an under-recognized issue and the underlying pathology is undetermined.

OBJECTIVE

To contribute at understanding the pathogenesis of fatigue in a naturalistic cohort of cognitively intact PD patients.

METHODS

In a Caucasian population of PD patients (n = 27), we evaluated to what extent fatigue (quantified as PFS-16 score) is associated with PD duration and with autonomic dysfunction, studied by both MIBG scintigraphy and autonomic nervous system testing. The latter included the head-up tilt test, Valsalva maneuver, deep breathing, and handgrip tests.

RESULTS

PFS-16 score correlated with disease duration (R = 0.57, p = 0.002). Fatigue showed a clear correlation with deep breathing test (R = - 0.53, p = 0.004) but not with the MIBG H/M ratios.

CONCLUSIONS

Our data are consistent with a multifactorial pathogenesis of fatigue and with effects of dopamine depletion in PD-related fatigue; on the other hand, our findings do not support a role for sympathetic denervation in PD-related fatigue.

Nonmotor Effects of Conventional and Transdermal Dopaminergic Therapies in Parkinson's Disease

Nonmotor symptoms (NMS) are an integral component of Parkinson's disease (PD). Because the burden and range of NMS are key determinants of quality of life for patients and caregivers, their management is a crucial issue in clinical practice. Although a range of NMS have a dopaminergic pathophysiological basis, this fact is underrecognized, and thus, they are often regarded as dopamine unresponsive symptoms. However, substantial evidence indicates that many NMS respond to oral and transdermal dopaminergic therapies. In contrast, certain NMS are exacerbated or even precipitated by dopaminergic drugs and these unwanted effects may be seriously dangerous. Therefore, a dopaminergic strategy for NMS should be based on a consideration of the benefits vs the risks in individual patients with PD.

Rasagiline for the symptomatic treatment of fatigue in Parkinson's disease

BACKGROUND

Fatigue affects 40% to 50% of all PD patients and is a leading cause of disability, with no clearly established or efficacious established treatments.

METHODS

In this double-blinded, placebo-controlled, pilot trial, we investigated whether rasagiline improved fatigue among PD patients. Subjects were randomized to 1 mg daily of rasagiline or placebo for 12 weeks. The primary endpoint was a change in the Modified Fatigue Impact Scale from baseline to week 12.

RESULTS

Thirty PD subjects (16 men), with Modified Fatigue Impact Scale baseline score of 67 ± 15, were randomized (16 to rasagiline vs. 14 to placebo). Significant improvement was noted in the mean Modified Fatigue Impact Scale score of the rasagiline group (12 points) as compared to placebo (8.5 points) from baseline to week 12 (P = 0.003).

CONCLUSION

In this pilot study, rasagiline at a dose of 1 mg per day improved fatigue. Larger randomized studies are needed to confirm this finding.

The Pathophysiology of Fatigue in Parkinson's Disease and its Pragmatic Management

BACKGROUND

Fatigue is 1 of the most common and most disabling symptoms among patients with Parkinson's disease (PD) and has a significant impact on their quality of life. Yet the pathophysiology of fatigue is poorly understood, while its treatment is "limited to an empirical approach based on plausible hypotheses."

METHODS

PubMed was searched for articles with the key words "Parkinson's disease" or "parkinsonism" and "fatigue" that were published by or before August 2015. The analysis of articles, which were selected on subjective grounds, was used to review the current knowledge of pathophysiology and treatment outcomes in studies focused on fatigue in PD.

CONCLUSIONS

Clinical and experimental findings support the view that fatigue is a primary manifestation of PD. The main hypothesized pathophysiological mechanisms include abnormal basal ganglia (BG)-cortical mechanisms, particularly frontal loops, and an imbalance between neurotransmitters (e.g., dopamine [DA] and serotonin), along with an altered hypothalamus-pituitary-adrenal axis, neuroinflammation, cardiac sympathetic denervation, etc. Pragmatic treatment of fatigue in patients with PD includes various pharmacological (dopaminergic and psychostimulant drugs, antidepressants) and nonpharmacological strategies, although current knowledge suffers from insufficient evidence to support the use of any drug or nondrug therapy.

Interventions for fatigue in Parkinson's disease

BACKGROUND

Factors contributing to subjective fatigue in people with idiopathic Parkinson's disease (PD) are not well known. This makes it difficult to manage fatigue effectively in PD.

OBJECTIVES

To evaluate the effects of pharmacological and non-pharmacological interventions, compared to an inactive control intervention, on subjective fatigue in people with PD.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); MEDLINE (via PubMed); Ovid EMBASE; EBSCO CINAHL; Ovid PsycINFO; PEDro; and the WHO International Clinical Trials Registry Platform Search Portal up to April 2015. References of included studies and identified review articles were screened for additional studies. There were no restrictions based on language, date of publication or study setting.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that report on subjective fatigue in people with PD.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data collection and risk of bias assessments.

MAIN RESULTS

Eleven studies were eligible for this systematic review, with a total of 1817 people. Three studies included only people who experienced clinically relevant fatigue (Fatigue Severity Scale score ≥ 4 out of 7 or Multidimensional Fatigue Inventory total score > 48 out of 100), whereas all other studies did not select participants on the basis of experienced fatigue. Nine studies investigated the effects of medication (i.e. levodopa-carbidopa, memantine, rasagiline, caffeine, methylphenidate, modafinil or doxepin) on subjective fatigue. All studies were placebo controlled. There was insufficient evidence to determine the effect of doxepin on the impact of fatigue on activities in daily life (ADL) or fatigue severity (one study, N = 12, standardised mean difference (SMD) = -1.50, 95% confidence interval (CI) -2.84 to -0.15; low quality evidence). We found high quality evidence that rasagiline reduced or slowed down the progression of physical aspects of fatigue (one study, N = 1176, SMD = -0.27, 95% CI -0.39 to -0.16, I(2) = 0%). None of the other pharmacological interventions affected subjective fatigue in PD. With regard to adverse effects, only levodopa-carbidopa showed an increase for the risk of nausea (one study, N = 361, risk ratio (RR) = 1.85, 95% CI 1.05 to 3.27; high quality evidence). Two studies investigated the effect of exercise on fatigue compared with usual care. We found low quality evidence for the effect of exercise on reducing the impact of fatigue on ADL or fatigue severity (two studies, N = 57, SMD = -0.45, 95% CI -1.21 to 0.32, I(2) = 44%).

AUTHORS' CONCLUSIONS

Based on the current evidence, no clear recommendations for the treatment of subjective fatigue in PD can be provided. Doxepin may reduce the impact of fatigue on ADL and fatigue severity; however, this finding has to be confirmed in high quality studies. Rasagiline may be effective in reducing levels of physical fatigue in PD. No evidence was found for the effectiveness of levodopa-carbidopa, memantine, caffeine, methylphenidate, modafinil or exercise. Studies are needed to investigate the effect of exercise intensity on exercise capacity and subjective fatigue. Future studies should focus on interventions that address the maladaptive behavioural or cognitive aspects of fatigue in people with PD. Characteristics, such as severity and nature of perceived fatigue and underlying mood disorders should be considered to identify responders and non-responders when studying interventions for fatigue. The development of a core-set of self-report fatigue questionnaires with established responsiveness and known minimal important difference values will facilitate the interpretation of change in fatigue scores.

Dopamine receptor agonists for Parkinson's disease

INTRODUCTION

Prolonged administration of l-3,4-dihydroxyphenylalanine (l-DOPA) for Parkinson's disease (PD) is hampered by motor complications related to the progressive incapacity of residual nigrostriatal neurons to properly utilize the drug. Direct stimulation of dopaminergic (DAergic) receptors with specific compounds (DA agonists) has, therefore, become an additional therapeutic tool for PD.

AREAS COVERED

DA agonists have considerable anti-parkinsonian symptomatic efficacy, although they are less potent than l-DOPA. This review summarizes pre-clinical and clinical data on DA agonists and their role in treating PD. Specific focus was put on second-generation, first-line non-ergolinic DA agonists and their motor, non-motor and putative neuroprotective effects. The anti-parkinsonian potential of recently developed DA agonists that reached Phase II and III clinical trials was also addressed.

EXPERT OPINION

DA agonists can be useful along the whole natural course of PD, as monotherapy in the initial phase or combined with l-DOPA in advanced PD. Extended-release formulations have been developed for second-generation DA agonists, which are better appreciated by patients. Neuroprotective properties have been proposed for DA agonists, based on pre-clinical studies, but never convincingly demonstrated in patients. New DA agonists, with better symptomatic efficacy and devoid of the side effects that characterize current compounds, are needed.