A Stage-Based Approach to Therapy in Parkinson's Disease

Sex-dependent associations of serum BDNF, glycolipid metabolism and cognitive impairments in Parkinson's disease with depression: a comprehensive analysis

Brain-derived neurotrophic factor (BDNF) and glycolipid metabolism have been implicated in cognitive impairments and depression among Parkinson's disease (PD). However, the role of sex differences in this relationship remains elusive. This study aimed to investigate the potential sex differences in the link between serum BDNF levels, glycolipid metabolism and cognitive performance among depressive PD patients. PD patients comprising 108 individuals with depression and 108 without depression were recruited for this study. Cognitive function was assessed using the Montreal Cognitive Assessment Beijing version (MOCA-BJ). The severity of depressive symptoms was assessed using the Hamilton Depression Rating Scale (HAMD-17), while motor symptoms were evaluated using the Revised Hoehn and Yahr rating scale (H-Y) and the Unified Parkinson's Disease Rating Scale Part III (UPDRS-III). Laboratory testing and enzyme-linked immunosorbent assay (ELISA) are used to measure serum levels of glycolipid metabolism and BDNF. Females showed superior performance in delayed recall (all p < 0.05), male PD patients exhibited higher scores in naming tasks compared to females in non-depression group. There was no sex differences in serum BDNF levels between depression and non-depression groups. Liner regression analysis indicated BDNF as an independent risk factor for language deficits in male PD patients with depression (p < 0.05), while cholesterol (CHOL) emerged as a cognitive influencing factor, particularly in delayed recall among male PD patients with depression (p < 0.05). Our study reveals extensive cognitive impairments in PD patients with depression. Moreover, BDNF and CHOL may contribute to the pathological mechanisms underlying cognitive deficits, particularly in male patients with depression.

The Potentiality of Natural Products and Herbal Medicine as Novel Medications for Parkinson's Disease: A Promising Therapeutic Approach

As the global population ages, the prevalence of Parkinson's disease (PD) is steadily on the rise. PD demonstrates chronic and progressive characteristics, and many cases can transition into dementia. This increases societal and economic burdens, emphasizing the need to find effective treatments. Among the widely recognized causes of PD is the abnormal accumulation of proteins, and autophagy dysfunction accelerates this accumulation. The resultant Lewy bodies are also commonly found in Alzheimer's disease patients, suggesting an increased potential for the onset of dementia. Additionally, the production of free radicals due to mitochondrial dysfunction contributes to neuronal damage and degeneration. The activation of astrocytes and the M1 phenotype of microglia promote damage to dopamine neurons. The drugs currently used for PD only delay the clinical progression and exacerbation of the disease without targeting its root cause, and come with various side effects. Thus, there is a demand for treatments with fewer side effects, with much potential offered by natural products. In this study, we reviewed a total of 14 articles related to herbal medicines and natural products and investigated their relevance to possible PD treatment. The results showed that the reviewed herbal medicines and natural products are effective against lysosomal disorder, mitochondrial dysfunction, and inflammation, key mechanisms underlying PD. Therefore, natural products and herbal medicines can reduce neurotoxicity and might improve both motor and non-motor symptoms associated with PD. Furthermore, these products, with their multi-target effects, enhance bioavailability, inhibit antibiotic resistance, and might additionally eliminate side effects, making them good alternative therapies for PD treatment.

The central role of the Thalamus in psychosis, lessons from neurodegenerative diseases and psychedelics

The PD-DLB psychosis complex found in Parkinson's disease (PD) and Dementia with Lewy Bodies (DLB) includes hallucinations, Somatic Symptom/Functional Disorders, and delusions. These disorders exhibit similar presentation patterns and progression. Mechanisms at the root of these symptoms also share similarities with processes promoting altered states of consciousness found in Rapid Eye Movement sleep, psychiatric disorders, or the intake of psychedelic compounds. We propose that these mechanisms find a crucial driver and trigger in the dysregulated activity of high-order thalamic nuclei set in motion by ThalamoCortical Dysrhythmia (TCD). TCD generates the loss of finely tuned cortico-cortical modulations promoted by the thalamus and unleashes the aberrant activity of the Default Mode Network (DMN). TCD moves in parallel with altered thalamic filtering of external and internal information. The process produces an input overload to the cortex, thereby exacerbating DMN decoupling from task-positive networks. These phenomena alter the brain metastability, creating dreamlike, dissociative, or altered states of consciousness. In support of this hypothesis, mind-altering psychedelic drugs also modulate thalamic-cortical pathways. Understanding the pathophysiological background of these conditions provides a conceptual bridge between neurology and psychiatry, thereby helping to generate a promising and converging area of investigation and therapeutic efforts.

An update on the pharmacogenetic considerations when prescribing dopamine receptor agonists for Parkinson's disease

INTRODUCTION

Parkinson's disease is a chronic neurodegenerative multisystemic disorder that affects approximately 2% of the population over 65 years old. This disorder is characterized by motor symptoms which are frequently accompanied by non-motor symptoms such as cognitive disorders. Current drug therapies aim to reduce the symptoms and increase the patient's life expectancy. Nevertheless, there is heterogeneity in therapy response in terms of efficacy and adverse effects. This wide range in response may be linked to genetic variability. Thus, it has been suggested that pharmacogenomics may help to tailor and personalize drug therapy for Parkinson's disease.

AREAS COVERED

This review describes and updates the clinical impact of genetic factors associated with the efficacy and adverse drug reactions related to common medications used to treat Parkinson's disease. Additionally, we highlight current informative recommendations for the drug treatment of Parkinson's disease.

EXPERT OPINION

The pharmacokinetic, pharmacodynamic, and safety profiles of Parkinson's disease drugs do not favor the development of pharmacogenetic tests with a high probability of success. The chances of obtaining ground-breaking pharmacogenetics biomarkers for Parkinson's disease therapy are limited. Nevertheless, additional information on the metabolism of certain drugs, and an analysis of the potential of pharmacogenetics in novel drugs could be of interest.

Low serum uric acid levels and levodopa-induced dyskinesia in Parkinson's disease

BACKGROUND

Levodopa is the most used and effective medication for motor symptoms of Parkinson disease (PD), its long-term use is associated with the appearance of levodopa-induced dyskinesia (LID). Uric acid (UA) is believed to play an important neuroprotective role in PD.

OBJECTIVE

To investigate if serum UA levels are related with the presence of LIDs in PD patients. Also, we investigated the associations among UA levels and clinical features of PD.

METHODS

We enrolled 81 PD patients (dyskinesia = 48; no dyskinesia = 33) in the present study. A blood sample was collected to evaluate serum UA levels, clinical evaluation included the following instruments: Montreal Cognitive Assessment (MoCA), Beck Depression Inventory II (BDI-II), MDS-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Hoehn and Yahr (HY), and the sub-item 4.1 of MDS-UPDRS IV (score ≥ 1). Additional relevant clinical information was obtained by a clinical questionnaire.

RESULTS

Serum UA levels were lower in the dyskinesia group when compared with the no dyskinesia group. The same result was found in the UA levels of both men and women. The multivariate analysis showed lower uric acid levels were significantly associated with having dyskinesia (odds ratio [OR] = 0.424; 95% confidence interval [CI]: 0.221-0.746; p = 0.005). Additional analysis verified that serum UA levels are inversely correlated with depressive symptoms, disease duration, MDS-UPDRS IV and time spent with dyskinesia. A positive correlation was found with age at onset of PD symptoms.

CONCLUSIONS

The present study provides a possible role of serum UA levels in LID present in PD patients.

Neurotrophic factor-based pharmacological approaches in neurological disorders

Aging is a physiological event dependent on multiple pathways that are linked to lifespan and processes leading to cognitive decline. This process represents the major risk factor for aging-related diseases such as Alzheimer's disease, Parkinson's disease, and ischemic stroke. The incidence of all these pathologies increases exponentially with age. Research on aging biology has currently focused on elucidating molecular mechanisms leading to the development of those pathologies. Cognitive deficit and neurodegeneration, common features of aging-related pathologies, are related to the alteration of the activity and levels of neurotrophic factors, such as brain-derived neurotrophic factor, nerve growth factor, and glial cell-derived neurotrophic factor. For this reason, treatments that modulate neurotrophin levels have acquired a great deal of interest in preventing neurodegeneration and promoting neural regeneration in several neurological diseases. Those treatments include both the direct administration of neurotrophic factors and the induced expression with viral vectors, neurotrophins' binding with biomaterials or other molecules to increase their bioavailability but also cell-based therapies. Considering neurotrophins' crucial role in aging pathologies, here we discuss the involvement of several neurotrophic factors in the most common brain aging-related diseases and the most recent therapeutic approaches that provide direct and sustained neurotrophic support.

Psychosis Management in Lewy Body Dementia: A Comprehensive Clinical Approach

Lewy body dementia (LBD) is asynucleinopathy that results in clinical manifestation of motor and neuropsychiatric symptoms. The disease burden associated with psychosis in LBD patients is significantly higher compared to other types of dementia or even to LBD without psychosis. Effective care management processes should include consideration of de-prescribing any offending agents including anticholinergics and dopaminergic agents, followed by nonpharmacological and low risk pharmacological approach. If addition of pharmacological agents is required, consideration should be given to acetylcholinesterase inhibitors, pimavanserin and atypical antipsychotics such as quetiapine or clozapine. Side effects of these medications should be considered prior to selection and initiation of a medication regimen. Goals of care and functional assessment are a crucial part of the optimized care plan, given overall guarded prognosis, in the context of numerous complications observed in this population. Palliative care consultation could facilitate symptom control and timely enrollment into hospice if consistent with patient's goals.

Anodal Transcranial Direct Current Stimulation Could Modulate Cortical Excitability and the Central Cholinergic System in Akinetic Rigid-Type Parkinson's Disease: Pilot Study

Background

Transcranial direct current stimulation (tDCS) is a non-invasive technique that has been widely studied as an alternative treatment for Parkinson's disease (PD). However, its clinical benefit remains unclear. In this study, we aimed to investigate the effect of tDCS on the central cholinergic system and cortical excitability in mainly akinetic rigid-type patients with PD.

Methods

In total, 18 patients with PD were prospectively enrolled and underwent 5 sessions of anodal tDCS on the M1 area, which is on the contralateral side of the dominant hand. We excluded patients with PD who had evident resting tremor of the hand to reduce the artifact of electrophysiologic findings. We compared clinical scales reflecting motor, cognitive, and mood symptoms between pre- and post-tDCS. Additionally, we investigated the changes in electrophysiologic parameters, such as short latency afferent inhibition (SAI) (%), which reflects the central cholinergic system.

Results

The United Parkinson's Disease Rating Scale Part 3 (UPDRS-III), the Korean-Montreal Cognitive Assessment (MoCA-K), and Beck Depression Inventory (BDI) scores were significantly improved after anodal tDCS (p < 0.01, p < 0.01, and p < 0.01). Moreover, motor evoked potential amplitude ratio (MEPAR) (%) and integrated SAI showed significant improvement after tDCS (p < 0.01 and p < 0.01). The mean values of the change in integrated SAI (%) were significantly correlated with the changes in UPDRS-III scores; however, the MoCA-K and BDI scores did not show differences.

Conclusions

Anodal tDCS could influence the central cholinergic system, such as frontal cortical excitability and depression in PD. This mechanism could underlie the clinical benefit of tDCS in patients with PD.

N-methylated diazabicyclo[3.2.2]nonane substituted triterpenoic acids are excellent, hyperbolic and selective inhibitors for butyrylcholinesterase

Triterpenoic acids (oleanolic, ursolic, betulinic, platanic and glycyrrhetinic acid) were acetylated and coupled with 1,3- or 1,4-diazabicyclo[3.2.2]nonanes to yield amides. Reaction of these amides with methyl iodide at the distal nitrogen of the bicyclic system gave the corresponding quaternary ammonium salts. These compounds were shown to act as excellent inhibitors of the enzyme butyrylcholinesterase (BChE) while being only weak inhibitors for acetylcholinesterase (AChE). Evaluation of the enzyme kinetics revealed these compounds to act as hyperbolic inhibitors for BChE while the results from molecular modeling gave an explanation for their selectivity between AChE and BChE.

Relationship between sleep disorders and neuropsychiatric symptoms in Parkinson's disease: A narrative review

Aim: The objective of this narrative review was to describe the versatile links between mental status and sleep in patients with Parkinson's disease. Methods: We searched randomized controlled studies, observational studies, meta-analyses, systematic reviews, and case reports written in English in PubMed during 2015 - 2021. Additionally, to ensure the completeness of the review, a second, more in-depth literature search was performed using the same electronic database with the search inquiries of increased specificity. Results: The information on pathophysiology, epidemiology, clinical features and risk factors was extracted and formed the basis for this review. Despite how widespread sleep disorders in Parkinson's disease are, there is no systematic information about their association with neuropsychiatric symptoms, such as depression, anxiety, impulse control disorders, apathy, cognitive impairment and psychosis. In this review, we described relationships between these non-motor symptoms of Parkinson's disease, their timeline occurrence, gap in knowledge and perspectives for further research. We suppose that early treatment of sleep disorders in patients with Parkinson's disease can reduce the incidence and extent of neuropsychiatric symptoms. Conclusion: We have demonstrated multiple, multidirectional relationships between sleep disorders and neuropsychiatric symptoms. However, some of them remain unexplored. The described knowledge can be applied to further study the possibility of influencing neuropsychiatric symptoms through the correction of sleep disorders in patients with different stages of Parkinson's disease.

Off Time Independently Affects Quality of Life in Advanced Parkinson's Disease (APD) Patients but Not in Non-APD Patients: Results from the Self-Reported Japanese Quality-of-Life Survey of Parkinson's Disease (JAQPAD) Study

INTRODUCTION

Parkinson's disease (PD) is characterized by a triad of motor symptoms and several nonmotor symptoms (NMS). Identifying the most appropriate treatment is essential for improving patient quality of life (QoL). However, it is still not known which PD symptoms more commonly affect patients with advanced PD (APD) versus non-APD. This study examined the factors that most affected the QoL of patients with APD (defined using the 5-2-1 criteria: ≥5 oral levodopa doses a day, off time ≥2 hours a day, or troublesome dyskinesia ≥1 hour a day) versus non-APD in a large Japanese population using the Japanese Quality-of-Life Survey of Parkinson's Disease (JAQPAD) study.

METHODS

Participants in this self-reported survey-based study included all members of the Japan Parkinson's Disease Association. Questionnaires assessing NMS and QoL (e.g., the 8-item PD Questionnaire [PDQ-8]) were included. Univariate and multivariate regression analyses were conducted to identify clinical factors impacting QoL using the PDQ-8 Summary Index (PDQ-8 SI).

RESULTS

Of the 3022 eligible patients, 864 were classified as having non-APD and 1599 as having APD. QoL as assessed by the PDQ-8 SI was notably worse in patients with APD versus non-APD (39.2 vs. 26.9, p < 0.0001). Although off time affected QoL only in patients with APD, PD duration and the NMS Questionnaire score significantly contributed to the QoL in both patients with APD and non-APD.

CONCLUSIONS

This study identified the factors more commonly associated with worse QoL in patients with APD versus non-APD. Our findings offer new insights for providing optimal treatment and improving treatment satisfaction in patients with PD.

Thimet Oligopeptidase—A Classical Enzyme with New Function and New Form

Peptidases generate bioactive peptides that can regulate cell signaling and mediate intercellular communication. While the processing of peptide precursors is initiated intracellularly, some modifications by peptidases may be conducted extracellularly. Thimet oligopeptidase (TOP) is a peptidase that processes neuroendocrine peptides with roles in mood, metabolism, and immune responses, among other functions. TOP also hydrolyzes angiotensin I to angiotensin 1–7, which may be involved in the pathophysiology of COVID-19 infection. Although TOP is primarily cytosolic, it can also be associated with the cell plasma membrane or secreted to the extracellular space. Recent work indicates that membrane-associated TOP can be released with extracellular vesicles (EVs) to the extracellular space. Here we briefly summarize the enzyme’s classical function in extracellular processing of neuroendocrine peptides, as well as its more recently understood role in intracellular processing of various peptides that impact human diseases. Finally, we discuss new findings of EV-associated TOP in the extracellular space.

Promising drug targets and associated therapeutic interventions in Parkinson's disease

Parkinson's disease (PD) is one of the most debilitating brain diseases. Despite the availability of symptomatic treatments, response towards the health of PD patients remains scarce. To fulfil the medical needs of the PD patients, an efficacious and etiological treatment is required. In this review, we have compiled the information covering limitations of current therapeutic options in PD, novel drug targets for PD, and finally, the role of some critical beneficial natural products to control the progression of PD.

Enhanced Delivery of Neuroactive Drugs via Nasal Delivery with a Self-Healing Supramolecular Gel

This paper reports the use of a self-assembling hydrogel as a delivery vehicle for the Parkinson's disease drug l-DOPA. Based on a two-component combination of an l-glutamine amide derivative and benzaldehyde, this gel has very soft rheological properties and self-healing characteristics. It is demonstrated that the gel can be formulated to encapsulate l-DOPA. These drug-loaded gels are characterized, and rapid release of the drug is obtained from the gel network. This drug-loaded hydrogel has appropriate rheological characteristics to be amenable for injection. This system is therefore tested as a vehicle for nasal delivery of neurologically-active drugs-a drug delivery strategy that can potentially avoid first pass liver metabolism and bypass the blood-brain barrier, hence enhancing brain uptake. In vitro tests indicate that the gel has biocompatibility with respect to nasal epithelial cells. Furthermore, animal studies demonstrate that the nasal delivery of a gel loaded with 3 H-labeled l-DOPA out-performed a simple intranasal l-DOPA solution. This is attributed to longer residence times of the gel in the nasal cavity resulting in increased blood and brain concentrations. It is demonstrated that the likely routes of brain penetration of intranasally-delivered l-DOPA gel involve the trigeminal and olfactory nerves connecting to other brain regions.

Can Task Specificity Impact tDCS-Linked to Dual Task Training Gains in Parkinson's Disease? A Protocol for a Randomized Controlled Trial

Patients with Parkinson's disease (PD) have difficulties while performing dual-task activities, a condition present in everyday life. It is possible that strategies such as transcranial Direct Current Stimulation (tDCS) can be associated with motor training enriched with dual-task training to improve the performance of two concurrent tasks. Currently, it is unclear whether specific tasks and clinical conditions of PD patients have different results after the intervention. Therefore, the proposed randomized controlled trial will examine task-dependency in enhancing the effects of tDCS-linked rehabilitation training on PD and the relationships between baseline outcomes in responders and non-responders to therapy. Fifty-six patients with Parkinson's disease will be recruited to participate in this controlled, double-blind randomized multicentric clinical trial. Patients in modified Hoehn & Yahr stage 1.5-3, age between 40 and 70 years will be included. Subjects will be randomly assigned to an experimental group (EG) and a control group (CG). The EG will perform treadmill gait training associated with dual task exercises+tDCS, while the CG will only engage in treadmill gait training+tDCS. Blinded testers will assess patients before and after 12 intervention sessions and after a 4-week follow-up period. All patients will undergo a screening and an initial visit before being assessed for primary and secondary outcomes. The primary outcome measure is functional mobility measured by Timed Up and Go Test. Secondary outcomes include cognitive function, participation, motor function and body function and structure. This study will evaluate the effectiveness of an intervention protocol with tDCS, dual-task training and gait training in patients with PD. The study will also highlight the clinical factors and variability between individuals that could interfere in the training of a specific task and influence the therapeutic effect. Clinical Trial registration: www.ClinicalTrials.gov, identifier NCT04581590.

Super-enhancer-driven Sorting Nexin 5 expression promotes dopaminergic neuronal ferroptosis in Parkinson's disease models

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease worldwide. Recent studies revealed that the ferroptosis pathway is involved in the death process of dopaminergic neurons in PD. The aberrant endosomal sorting pathway, which results in aberrant iron level in eukaryotic cells, may serve a role in the ferroptosis pathway in PD condition. However, its specific molecular mechanisms remained unclear. In the present study, we performed chromatin immunoprecipitation (ChIP) assay, the rank ordering of super-enhancers (ROSE) algorithm, and RNA interference (RNAi) to explore the regulatory mechanism of PD-specific super-enhancer (SE) in the endosomal sorting pathway and ferroptosis pathway of 6-OHDA-lesioned rats and cells. The ChIP assay and ROSE algorithm results showed that there are specific SEs expression in 6-OHDA-lesioned SNc of PD rats, and the most significant expression gene is Sorting Nexin 5 (SNX5). SNX5 silencing by RNAi experiments significantly decreased the level of ferroptosis in 6-OHDA-lesioned PC12 cells, suggesting the correlation between the SNX5, ferroptosis, and PD. In conclusion, this study investigated the mechanism by which PD-specific SE driven SNX5 promoted the ferroptosis level in PD models. This study further improved the understanding of the mechanism of ferroptosis during PD injury and provided potential therapeutic targets and clinical diagnostic markers in PD condition.

Dl-3-n-Butylphthalide Alleviates Behavioral and Cognitive Symptoms Via Modulating Mitochondrial Dynamics in the A53T-α-Synuclein Mouse Model of Parkinson's Disease

Background

Aggregation and neurotoxicity of the presynaptic protein α-synuclein and the progressive loss of nigral dopaminergic neurons are believed to be the key hallmarks of Parkinson’s disease (PD). A53T mutant α-synuclein causes early onset PD and more severe manifestations. A growing body of evidence shows that misfolding or deposition of α-synuclein is linked to the maintenance of mitochondrial dynamics, which has been proven to play an important role in the pathogenesis of PD. It has been observed that Dl-3-n-butylphthalide (NBP) may be safe and effective in improving the non-tremor-dominant PD. However, the potential mechanism remains unclear. This study aimed to investigate whether NBP could decrease the loss of dopaminergic neurons and α-synuclein deposition and explore its possible neuroprotective mechanisms.

Methods

A total of 20 twelve-month-old human A53T α-synuclein transgenic mice and 10 matched adult C57BL/6 mice were included in the study; 10 adult C57BL/6 mice were selected as the control group and administered with saline (0.2 ml daily for 14 days); 20 human A53T α-synuclein transgenic mice were randomly divided into A53T group (treated in the same manner as in the control group) and A53T + NBP group (treated with NBP 0.2 ml daily for 14 days). Several markers of mitochondrial fission and fusion and mitophagy were determined, and the behavioral, olfactory, and cognitive symptoms were assessed as well.

Results

In the present study, it was observed that the A53T-α-synuclein PD mice exhibited anxiety-like behavioral disturbance, impairment of coordination ability, memory deficits, and olfactory dysfunction, loss of dopaminergic neurons, and α-synuclein accumulation. Meanwhile, the mitofusin 1 expression was significantly decreased, and the mitochondrial number and dynamin-related protein 1, Parkin, and LC3 levels were increased. The detected levels of all markers were reversed by NBP treatment, and the mitochondrial morphology was partially recovered.

Conclusion

In the present study, a valuable neuropharmacological role of NBP has been established in the A53T-α-synuclein PD mouse model. Possible neuroprotective mechanisms might be that NBP is involved in the maintenance of mitochondrial dynamics including mitochondrial fission and fusion and clearance of damaged mitochondria. It is essential to perform further experiments to shed light on the precise mechanisms of NBP on mitochondrial homeostasis.

Serum BDNF discriminates Parkinson's disease patients with depression from without depression and reflect motor severity and gender differences

OBJECTIVE

To evaluate the diagnostic value of serum Brain-derived neurotrophic factor (BDNF) levels for discriminating PD with depression from without depression, and to investigate whether serum BDNF levels were associated with motor severity and gender in depressed PD patients.

METHODS

Demographic and clinical data were collected from 122 PD patients with depression, 137 without depression and 110 healthy controls. All participants' serum BDNF concentrations were measured. Their motor abilities and activity were assessed by the Unified PD Rating Scale Part III (UPDRS III) score and the Hoehn and Yahr (H-Y) stage. Depression was scored using the 17-item Hamilton Rating Scale for Depression (HAMD-17). Associations were analyzed with multivariate regression.

RESULTS

The serum BDNF levels were lower in depressed PD patients compared to non-depressed PD patients and controls (p < 0.001). The BDNF levels were negatively correlated with UPDRS III score (r = - 0.54, p < 0.001) and H-Y stage (r = - 0.45, p < 0.001). Decreased BDNF levels were associated with women only among depressed PD patients (r = 0.45, p < 0.001). The HAMD-17 score was negatively correlated with BDNF levels (r = - 0.59, p < 0.001), and positively associated with UPDRS III score (r = 0.51, p < 0.001). Multiple regression analysis demonstrated that in the depressed PD patients, female, H-Y stage and UPDRS III score were independent contributors to the BDNF levels (p < 0.001; p = 0.006; p = 0.03, respectively), BDNF and UPDRS III score were independent contributors to HAMD-17 score (p < 0.001, p = 0.01, respectively).

CONCLUSIONS

Decreased serum BDNF levels may be a useful clinical biomarker of depression in PD patients. Serum BDNF may serve as a potential biomarker for motor severity of PD patients with depression, especially in female.

Apitherapy for Parkinson's Disease: A Focus on the Effects of Propolis and Royal Jelly

The vast increase of world's aging populations is associated with increased risk of age-related neurodegenerative diseases such as Parkinson's disease (PD). PD is a widespread disorder characterized by progressive loss of dopaminergic neurons in the substantia nigra, which encompasses a wide range of debilitating motor, emotional, cognitive, and physical symptoms. PD threatens the quality of life of millions of patients and their families. Additionally, public welfare and healthcare systems are burdened with its high cost of care. Available treatments provide only a symptomatic relief and produce a trail of noxious side effects, which increase noncompliance. Hence, researchers have recently focused on the use of nutraceuticals as safe adjunctive treatments of PD to limit its progress and associated damages in affected groups. Propolis is a common product of the beehive, which possesses a large number of therapeutic properties. Royal jelly (RJ) is a bee product that is fed to bee queens during their entire life, and it contributes to their high physical fitness, fertility, and long lifespan. Evidence suggests that propolis and RJ can promote health by preventing the occurrence of age-related debilitating diseases. Therefore, they have been used to treat various serious disorders such as diabetes mellitus, cardiovascular diseases, and cancer. Some evolving studies used these bee products to treat PD in animal models. However, a clear understanding of the collective effect of propolis and RJ as well as their mechanism of action in PD is lacking. This review evaluates the available literature for the effects of propolis and RJ on PD. Whenever possible, it elaborates on the underlying mechanisms through which they function in this disorder and offers insights for fruitful use of bee products in future clinical trials.

Impact of motor and nonmotor symptoms in Parkinson disease for the quality of life: The Japanese Quality-of-Life Survey of Parkinson Disease (JAQPAD) study

INTRODUCTION

Parkinson's disease (PD) is characterized by a range of classic motor symptoms and heterogeneous nonmotor symptoms that affect patients' quality of life (QoL). Studies have individually reported the effect of either motor or nonmotor symptoms on patients' QoL; however, a thorough assessment of the symptoms that have the greatest influence on QoL is limited. This JAQPAD study examined the effect of both motor and nonmotor symptoms and patient demographics on QoL in a large population of patients with PD in Japan.

METHODS

All members of the Japan Parkinson's Disease Association were invited to participate in the study. Questionnaires assessing wearing-off symptoms (the 9-item Wearing-Off Questionnaire [WOQ-9]), nonmotor symptoms (Non-Motor Symptoms Questionnaire [NMSQ]) and QoL (the 8-item Parkinson's Disease Questionnaire [PDQ-8]) were included. Multiple regression analyses assessed the effect of clinical factors on the PDQ-8 Summary Index (PDQ-8 SI). Spearman rank correlation coefficient (r) estimated the correlation between each subdomain score of nine NMSQ domains and the PDQ-8 SI.

RESULTS

A total of 3022 patients were included in the analysis. The PDQ-8 SI score correlated with off-time, age, duration of PD, work status, and the NMSQ total score and subdomain scores. Memory problems correlated most strongly with the PDQ-8 SI score (r = 0.4419), followed by mood (r = 0.4387) and digestive problems (r = 0.4341; p < 0.0001).

CONCLUSIONS

Physicians tend to focus on motor symptoms, while nonmotor symptoms often go under-recognized in clinical practice. This JAQPAD study highlights the importance of recognition and management of both motor and nonmotor symptoms, which together significantly affect patient QoL.

α-Bisabolol, a Dietary Bioactive Phytochemical Attenuates Dopaminergic Neurodegeneration through Modulation of Oxidative Stress, Neuroinflammation and Apoptosis in Rotenone-Induced Rat Model of Parkinson's disease

Rotenone (ROT), a plant-derived pesticide is a well-known environmental neurotoxin associated with causation of Parkinson’s disease (PD). ROT impairs mitochondrial dysfunction being mitochondrial complex-I (MC-1) inhibitor and perturbs antioxidant-oxidant balance that contributes to the onset and development of neuroinflammation and neurodegeneration in PD. Due to the scarcity of agents to prevent the disease or to cure or halt the progression of symptoms of PD, the focus is on exploring agents from naturally occurring dietary phytochemicals. Among numerous phytochemicals, α-Bisabolol (BSB), natural monocyclic sesquiterpene alcohol found in many ornamental flowers and edible plants garnered attention due to its potent pharmacological properties and therapeutic potential. Therefore, the present study investigated the neuroprotective effects of BSB in a rat model of ROT-induced dopaminergic neurodegeneration, a pathogenic feature of PD and underlying mechanism targeting oxidative stress, inflammation and apoptosis. BSB treatment significantly prevented ROT-induced loss of dopaminergic neurons and fibers in the substantia nigra and striatum respectively. BSB treatment also attenuated ROT-induced oxidative stress evidenced by inhibition of MDA formation and GSH depletion as well as improvement in antioxidant enzymes, SOD and catalase. BSB treatment also attenuated ROT-induced activation of the glial cells as well as the induction and release of proinflammatory cytokines (IL-1β, IL-6 and TNF-α) and inflammatory mediators (iNOS and COX-2) in the striatum. In addition to countering oxidative stress and inflammation, BSB also attenuated apoptosis of dopaminergic neurons by attenuating downregulation of anti-apoptotic protein Bcl-2 and upregulation of pro-apoptotic proteins Bax, cleaved caspases-3 and 9. Further, BSB was observed to attenuate mitochondrial dysfunction by inhibiting mitochondrial lipid peroxidation, cytochrome-C release and reinstates the levels/activity of ATP and MC-I. The findings of the study demonstrate that BSB treatment salvaged dopaminergic neurons, attenuated microglia and astrocyte activation, induction of inflammatory mediators, proinflammatory cytokines and reduced the expression of pro-apoptotic markers. The in vitro study on ABTS radical revealed the antioxidant potential of BSB. The results of the present study are clearly suggestive of the neuroprotective effects of BSB through antioxidant, anti-inflammatory and anti-apoptotic properties in ROT-induced model of PD.

Status and future directions of clinical trials in Parkinson's disease

Novel therapies are needed to treat Parkinson's disease (PD) in which the clinical unmet need is pressing. Currently, no clinically available therapeutic strategy can either retard or reverse PD or repair its pathological consequences. l-DOPA (levodopa) is still the gold standard therapy for motor symptoms yet symptomatic therapies for both motor and non-motor symptoms are improving. Many on-going, intervention trials cover a broad range of targets, including cell replacement and gene therapy approaches, quality of life improving technologies, and disease-modifying strategies (e.g., controlling aberrant α-synuclein accumulation and regulating cellular/neuronal bioenergetics). Notably, the repurposing of glucagon-like peptide-1 analogues with potential disease-modifying effects based on metabolic pathology associated with PD has been promising. Nevertheless, there is a clear need for improved therapeutic and diagnostic options, disease progression tracking and patient stratification capabilities to deliver personalized treatment and optimize trial design. This review discusses some of the risk factors and consequent pathology associated with PD and particularly the metabolic aspects of PD, novel therapies targeting these pathologies (e.g., mitochondrial and lysosomal dysfunction, oxidative stress, and inflammation/neuroinflammation), including the repurposing of metabolic therapies, and unmet needs as potential drivers for future clinical trials and research in PD.

Challenges and opportunities to include patient-centric product design in industrial medicines development to improve therapeutic goals

In the past, drug developers in industry chose approaches mainly focusing on the drug product's efficacy, safety and quality according to the level required by regulatory expectations stipulated in guidelines, pharmacopoeia and other regulatory provisions. By putting more focus on the patient perspective, regulatory authorities are currently raising their requirements regarding successful product submissions. The increasing involvement of patients in the product development process (e.g. conduction of human factor use tests, integration of feedback from patient and patient advisory groups into clinical programmes) requires adaptations to the existing and established industrial drug development processes without compromising fast patient access to innovative therapies. This review provides an expert opinion on the emerging challenges and opportunities to implement a patient-centric approach into new drug development programmes. The aim is to better understand the challenge of finding the right balance between bringing innovative drugs fast to the patients and to develop these in parallel in a patient-centric product form as well as why this is an opportunity and how stakeholder parties (e.g. patients, clinicians, pharmacists, caregivers, regulators) can provide support to achieve desired outcomes.

Exploring the Predictors of Rapid Eye Movement Sleep Behavior Disorder for Parkinson's Disease Patients Using Classifier Ensemble

The rapid eye movement sleep behavior disorder (RBD) of Parkinson's disease (PD) patients can be improved with medications such as donepezil as long as it is diagnosed with a thorough medical examination, since identifying a high-risk group of RBD is a critical issue to treat PD. This study develops a model for predicting the high-risk groups of RBD using random forest (RF) and provides baseline information for selecting subjects for polysomnography. Subjects consisted of 350 PD patients (Parkinson's disease with normal cognition (PD-NC) = 48; Parkinson's disease with mild cognitive impairment (PD-MCI) = 199; Parkinson's disease dementia (PDD) = 103) aged 60 years and older. This study compares the prediction performance of RF, discriminant analysis, classification and regression tree (CART), radial basis function (RBF) neural network, and logistic regression model to select a final model with the best model performance and presents the variable importance of the final model's variable. As a result of analysis, the sensitivity of RF (79%) was superior to other models (discriminant analysis = 14%, CART = 32%, RBF neural network = 25%, and logistic regression = 51%). It was confirmed that age, the motor score of Untitled Parkinson's Disease Rating (UPDRS), the total score of UPDRS, the age when a subject was diagnosed with PD first time, the Korean Mini Mental State Examination, and Korean Instrumental Activities of Daily Living, were major variables with high weight for predicting RBD. Among them, age was the most important factor. The model for predicting Parkinson's disease RBD developed in this study will contribute to the screening of patients who should receive a video-polysomnography.

Roles of the PI3K/AKT/mTOR signalling pathways in neurodegenerative diseases and tumours

The PI3 K/AKT/mTOR signalling pathway plays an important role in the regulation of signal transduction and biological processes such as cell proliferation, apoptosis, metabolism and angiogenesis. Compared with those of other signalling pathways, the components of the PI3K/AKT/mTOR signalling pathway are complicated. The regulatory mechanisms and biological functions of the PI3K/AKT/mTOR signalling pathway are important in many human diseases, including ischaemic brain injury, neurodegenerative diseases, and tumours. PI3K/AKT/mTOR signalling pathway inhibitors include single-component and dual inhibitors. Numerous PI3K inhibitors have exhibited good results in preclinical studies, and some have been clinically tested in haematologic malignancies and solid tumours. In this review, we briefly summarize the results of research on the PI3K/AKT/mTOR pathway and discuss the structural composition, activation, communication processes, regulatory mechanisms and biological functions of the PI3K/AKT/mTOR signalling pathway in the pathogenesis of neurodegenerative diseases and tumours.

Neurobiological findings underlying depressive behavior in Parkinson's disease: A review

Parkinson's disease (PD) is one of the most prevalent neurodegenerative diseases in the world with a harmful impact on the quality of life. Although its clinical diagnosis is based on motor symptoms such as resting tremor, postural instability, slow gait, and muscle stiffness, this disorder is also characterized by the presence of early emotional impairment, including features such as depression, anxiety, fatigue, and apathy. Depression is the main emotional manifestation associated with PD and the mechanisms involved in its pathophysiology have been extensively investigated however, it is not yet completely elucidated. In addition to monoaminergic imbalance, immunological and gut microbiota changes have been associated with depression in PD. Besides, a patient group appears be refractory to the treatment available currently. This review emphasizes the mainly neuromolecular findings of the PD-associated depression as well as discuss novel and potential pharmacological and non-pharmacological therapeutic strategies.

The Pharmacology of Visual Hallucinations in Synucleinopathies

Visual hallucinations (VH) are commonly found in the course of synucleinopathies like Parkinson's disease and dementia with Lewy bodies. The incidence of VH in these conditions is so high that the absence of VH in the course of the disease should raise questions about the diagnosis. VH may take the form of early and simple phenomena or appear with late and complex presentations that include hallucinatory production and delusions. VH are an unmet treatment need. The review analyzes the past and recent hypotheses that are related to the underlying mechanisms of VH and then discusses their pharmacological modulation. Recent models for VH have been centered on the role played by the decoupling of the default mode network (DMN) when is released from the control of the fronto-parietal and salience networks. According to the proposed model, the process results in the perception of priors that are stored in the unconscious memory and the uncontrolled emergence of intrinsic narrative produced by the DMN. This DMN activity is triggered by the altered functioning of the thalamus and involves the dysregulated activity of the brain neurotransmitters. Historically, dopamine has been indicated as a major driver for the production of VH in synucleinopathies. In that context, nigrostriatal dysfunctions have been associated with the VH onset. The efficacy of antipsychotic compounds in VH treatment has further supported the notion of major involvement of dopamine in the production of the hallucinatory phenomena. However, more recent studies and growing evidence are also pointing toward an important role played by serotonergic and cholinergic dysfunctions. In that respect, in vivo and post-mortem studies have now proved that serotonergic impairment is often an early event in synucleinopathies. The prominent cholinergic impairment in DLB is also well established. Finally, glutamatergic and gamma aminobutyric acid (GABA)ergic modulations and changes in the overall balance between excitatory and inhibitory signaling are also contributing factors. The review provides an extensive overview of the pharmacology of VH and offers an up to date analysis of treatment options.

2-Hydroxy-N-phenylbenzamides and Their Esters Inhibit Acetylcholinesterase and Butyrylcholinesterase

The development of novel inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) represents a viable approach to alleviate Alzheimer’s disease. Thirty-six halogenated 2-hydroxy-N-phenylbenzamides (salicylanilides) with various substitution patterns and their esters with phosphorus-based acids were synthesized in yields of 72% to 92% and characterized. They were evaluated for in vitro inhibition of AChE from electric eel and BuChE from equine serum using modified Ellman’s spectrophotometric method. The benzamides exhibited a moderate inhibition of AChE with IC₅₀ values in a narrow concentration range from 33.1 to 85.8 µM. IC₅₀ values for BuChE were higher (53.5–228.4 µM). The majority of derivatives inhibit AChE more efficiently than BuChE and are comparable or superior to rivastigmine—an established cholinesterases inhibitor used in the treatment of Alzheimer’s disease. Phosphorus-based esters especially improved the activity against BuChE with 5-chloro-2-{[4-(trifluoromethyl)phenyl]carbamoyl}phenyl diethyl phosphite 5c superiority (IC₅₀ = 2.4 µM). This derivative was also the most selective inhibitor of BuChE. It caused a mixed inhibition of both cholinesterases and acted as a pseudo-irreversible inhibitor. Several structure-activity relationships were identified, e.g., favouring esters and benzamides obtained from 5-halogenosalicylic acids and polyhalogenated anilines. Both 2-hydroxy-N-phenylbenzamides and esters share convenient physicochemical properties for blood-brain-barrier penetration and thus central nervous system delivery.