Transcranial alternating current stimulation improves quality of life in Parkinson's disease: study protocol for a randomized, double-blind, controlled trial

BACKGROUND

The neural cells in the brains of patients with Parkinson's disease (PWP) display aberrant synchronized oscillatory activity within the beta frequency range. Additionally, enhanced gamma oscillations may serve as a compensatory mechanism for motor inhibition mediated by beta activity and also reinstate plasticity in the primary motor cortex affected by Parkinson's disease. Transcranial alternating current stimulation (tACS) can synchronize endogenous oscillations with exogenous rhythms, thereby modulating cortical activity. The objective of this study is to investigate whether the addition of tACS to multidisciplinary intensive rehabilitation treatment (MIRT) can improve symptoms of PWP so as to enhance the quality of life in individuals with Parkinson's disease based on the central-peripheral-central theory.

METHODS

The present study was a randomized, double-blind trial that enrolled 60 individuals with Parkinson's disease aged between 45 and 70 years, who had Hoehn-Yahr scale scores ranging from 1 to 3. Participants were randomly assigned in a 1:1 ratio to either the tACS + MIRT group or the sham-tACS + MIRT group. The trial consisted of a two-week double-blind treatment period followed by a 24-week follow-up period, resulting in a total duration of twenty-six weeks. The primary outcome measured the change in PDQ-39 scores from baseline (T0) to 4 weeks (T2), 12 weeks (T3), and 24 weeks (T4) after completion of the intervention. The secondary outcome assessed changes in MDS-UPDRS III scores at T0, the end of intervention (T1), T2, T3, and T4. Additional clinical assessments and mechanistic studies were conducted as tertiary outcomes.

DISCUSSION

The objective of this study is to demonstrate that tACS can enhance overall functionality and improve quality of life in PWP, based on the framework of MIRT. Additionally, it seeks to establish a potential correlation between these therapeutic effects and neuroplasticity alterations in relevant brain regions. The efficacy of tACS will be assessed during the follow-up period in order to optimize neuroplasticity and enhance its potential impact on rehabilitation efficiency for PWP.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2300071969. Registered on 30 May 2023.

Withania somnifera (L.) Dunal, a Potential Source of Phytochemicals for Treating Neurodegenerative Diseases: A Systematic Review

Withania somnifera (L.) Dunal is a medicinal plant belonging to the traditional Indian medical system, showing various therapeutic effects such as anti-cancer, anti-inflammatory, anti-microbial, anti-diabetic, and hepatoprotective activity. Of great interest is W. somnifera's potential beneficial effect against neurodegenerative diseases, since the authorized medicinal treatments can only delay disease progression and provide symptomatic relief and are not without side effects. A systematic search of PubMed and Scopus databases was performed to identify preclinical and clinical studies focusing on the applications of W. somnifera in preventing neurodegenerative diseases. Only English articles and those containing the keywords (Withania somnifera AND "neurodegenerative diseases", "neuroprotective effects", "Huntington", "Parkinson", "Alzheimer", "Amyotrophic Lateral Sclerosis", "neurological disorders") in the title or abstract were considered. Reviews, editorials, letters, meta-analyses, conference papers, short surveys, and book chapters were not considered. Selected articles were grouped by pathologies and summarized, considering the mechanism of action. The quality assessment and the risk of bias were performed using the Cochrane Handbook for Systematic Reviews of Interventions checklist. This review uses a systematic approach to summarize the results from 60 investigations to highlight the potential role of W. somnifera and its specialized metabolites in treating or preventing neurodegenerative diseases.

Fasting glucose variability and risk of dementia in Parkinson's disease: a 9-year longitudinal follow-up study of a nationwide cohort

Background

Diabetes is associated with an increased risk of Parkinson's disease dementia (PDD); however, it is unknown whether this association is dependent on continuous hyperglycemia, hypoglycemic events, or glycemic variability. We aimed to investigate the relationship between visit-to-visit fasting glucose variability and PDD development in patients with Parkinson's disease (PD).

Methods

Using data from the Korean National Health Insurance Service, we examined 9,264 patients aged ≥40 years with de novo Parkinson's disease (PD) who underwent ≥3 health examinations and were followed up until December 2019. Glucose variability was measured using the coefficient of variation, variability independent of the mean, and average real variability. Fine and Gray competing regression analysis was performed to determine the effect of glucose variability on incident PDD.

Results

During the 9.5-year follow-up period, 1,757 of 9,264 (19.0%) patients developed PDD. Patients with a higher visit-to-visit glucose variability had a higher risk of future PDD. In the multivariable adjusted model, patients with PD in the highest quartile (subdistribution hazard ratio [SHR] = 1.50, 95% CI 1.19 to 1.88), quartile 3 (SHR = 1.29, 95% CI 1.02 to 1.62), and quartile 2 (SHR = 1.30, 95% CI 1.04 to 1.63) were independently associated with a higher risk of PDD than those in the lowest quartile.

Conclusion

We highlighted the effect of long-term glucose variability on the development of PDD in patients with PD. Furthermore, our findings suggest that preventive measures for constant glucose control may be necessary to prevent PDD.

Mesenchymal stromal cell biotherapy for Parkinson's disease premotor symptoms

Parkinson's disease (PD) is a neurodegenerative disorder with motor deficits due to nigrostriatal dopamine depletion and with the non-motor/premotor symptoms (NMS) such as anxiety, cognitive dysfunction, depression, hyposmia, and sleep disorders. NMS is presented in at least one-fifth of the patients with PD. With the histological information being investigated, stem cells are shown to provide neurotrophic supports and cellular replacement in the damaging brain areas under PD conditions. Pathological change of progressive PD includes degeneration and loss of dopaminergic neurons in the substantia nigra of the midbrain. The current stem cell beneficial effect addresses dopamine boost for the striatal neurons and gliovascular mechanisms as competing for validated PD drug targets. In addition, there are clinical interventions for improving the patient's NMS and targeting their autonomic dysfunction, dementia, mood disorders, or sleep problems. In our and many others' research using brain injury models, multipotent mesenchymal stromal cells demonstrate an additional and unique ability to alleviate depressive-like behaviors, independent of an accelerated motor recovery. Intranasal delivery of the stem cells is discussed for it is extensively tested in rodent animal models of neurological and psychiatric disorders. In this review, we attempt to discuss the repairing potentials of transplanted cells into parkinsonism pathological regions of motor deficits and focus on preventive and treatment effects. From new approaches in the PD biological therapy, it is believed that it can as well benefit patients against PD-NMS.

Effects of rasagiline combined with levodopa and benserazide hydrochloride on motor function and homocysteine and IGF-1 levels in elderly patients with Parkinson's disease

BACKGROUND

During the course of their illness, people with Parkinson's disease may see changes in their insulin-like growth factor (IGF-1) and serum homocysteine (Hcy) indices. In this study, patients with intermediate to severe Parkinson's disease were examined for how Resagiline and levodopa and benserazide hydrochloride affected their motor performance, serum levels of homocysteine (Hcy), and insulin-like growth factor (IGF-1).

METHODS

From June 2020 to December 2021, a total of 100+ cases of Parkinson's patients over 60 years old in the middle and late stages of Parkinson's were seen in the outpatient and inpatient departments of the Third People's Hospital of Chengdu City and had a detailed observation record, and according to the inclusion criteria, the patients who met the criteria were randomly grouped into a clinical observation group and a control group. The subjects in the control group received only levodopa and benserazide hydrochloride treatment, while the observation group was treated with Resagiline in combination with the clinical control group. The total treatment observation period was 1 year for both groups, and the motor function and serum Hcy and IGF-1 indexes of both groups were compared after the end of treatment.

RESULTS

We randomly and evenly grouped 64 patients who met the requirements of the inclusion criteria into a clinical observation group and a control group, each with 32 patients, from among 168 patients over 60 years of age with detailed observation records in the middle and late stages of Parkinson's. After the 1-year observation period, we found that the total effective rate after treatment in the clinical observation group (93.75%) and significantly higher than that in the control group (68.75%) (P < 0.05); after 1 year of treatment, the UPDRS score decreased in both groups, and the observation group was significantly lower than the control group (P < 0.05); after treatment, serum Hcy decreased and IGF-1 increased in both groups, and the observation group was higher than the control group mean values (P < 0.05).

CONCLUSIONS

In patients with Parkinson's disease who are in the middle and late stages of the disease, the administration of Resagiline combined with levodopa and benserazide hydrochloride can significantly lower the body's serum Hcy level, significantly raise IGF-1 levels, and significantly improve motor function in patients with Parkinson's disease. It can also have significant therapeutic effects.

Potential benefits of medium chain fatty acids in aging and neurodegenerative disease

Neurodegenerative diseases are a large class of neurological disorders characterized by progressive dysfunction and death of neurones. Examples include Alzheimer's disease, Parkinson's disease, frontotemporal dementia, and amyotrophic lateral sclerosis. Aging is the primary risk factor for neurodegeneration; individuals over 65 are more likely to suffer from a neurodegenerative disease, with prevalence increasing with age. As the population ages, the social and economic burden caused by these diseases will increase. Therefore, new therapies that address both aging and neurodegeneration are imperative. Ketogenic diets (KDs) are low carbohydrate, high-fat diets developed initially as an alternative treatment for epilepsy. The classic ketogenic diet provides energy via long-chain fatty acids (LCFAs); naturally occurring medium chain fatty acids (MCFAs), on the other hand, are the main components of the medium-chain triglyceride (MCT) ketogenic diet. MCT-based diets are more efficient at generating the ketone bodies that are used as a secondary energy source for neurones and astrocytes. However, ketone levels alone do not closely correlate with improved clinical symptoms. Recent findings suggest an alternative mode of action for the MCFAs, e.g., via improving mitochondrial biogenesis and glutamate receptor inhibition. MCFAs have been linked to the treatment of both aging and neurodegenerative disease via their effects on metabolism. Through action on multiple disease-related pathways, MCFAs are emerging as compounds with notable potential to promote healthy aging and ameliorate neurodegeneration. MCFAs have been shown to stimulate autophagy and restore mitochondrial function, which are found to be disrupted in aging and neurodegeneration. This review aims to provide insight into the metabolic benefits of MCFAs in neurodegenerative disease and healthy aging. We will discuss the use of MCFAs to combat dysregulation of autophagy and mitochondrial function in the context of "normal" aging, Parkinson's disease, amyotrophic lateral sclerosis and Alzheimer's disease.

Motor and non-motor features in Parkinson's Disease patients carrying GBA gene mutations

BACKGROUND

Mutations of the Glucocerebrosidase (GBA) gene are the most common genetic risk factor yet discovered for Parkinson's Disease (PD), being found in about 5-14% of Caucasian patients.

OBJECTIVE

We aimed to assess motor and non-motor symptoms (NMS) in patients with GBA-related PD (GBA-PD) in comparison with idiopathic PD (iPD) subjects using standardized and validated scales.

METHODS

Eleven (4 M, 7 F) patients with GBA-PD and 22 iPD patients, selected from the same cohort and matched for gender, age, and disease duration, were enrolled. The disease severity was assessed by Unified Parkinson's Disease Rating Scale-section III, gait disorder and falls by Freezing of Gait Questionnaire, and motor fluctuations by Wearing off questionnaire. NMS were evaluated using the following scales: Mini-Mental State Examination and extended neuropsychological battery, if required, Non-Motor Symptoms Scale, SCOPA-AUT Questionnaire, Apathy Evaluation Scale, Beck Depression Inventory, Epworth Sleepiness Scale, Restless Legs Syndrome Rating Scale, REM Sleep Behavior Disorder Screening Questionnaire, and Questionnaire for Impulsive-Compulsive Disorders in Parkinson's disease.

RESULTS

GBA-PD patients showed a more severe and rapidly progressive disease, and more frequent positive family history for PD, akinetic-rigid phenotype, postural instability, dementia, and psychosis in comparison to iPD. Two of three subjects carrying L444P mutation presented with early dementia. We also found a higher occurrence of fatigue, diurnal sleepiness, and intolerance to heat/cold in the carriers group.

CONCLUSIONS

Our results confirm that NMS and a more severe and faster disease course more frequently occur among GBA-PD patients in comparison to iPD.

Thymoquinone Prevents Dopaminergic Neurodegeneration by Attenuating Oxidative Stress Via the Nrf2/ARE Pathway

Studies have indicated that oxidative stress plays a crucial role in the development of Parkinson's disease (PD) and other neurodegenerative conditions. Research has also revealed that nuclear factor erythroid 2-related factor 2 (Nrf2) triggers the expression of antioxidant genes via a series of antioxidant response elements (AREs), thus preventing oxidative stress. Thymoquinone (TQ) is the bioactive component of Nigella sativa, a medicinal plant that exhibits antioxidant and neuroprotective effects. In the present study we examined whether TQ alleviates in vivo and in vitro neurodegeneration induced by 1-methyl-4-phenylpyridinium (MPP⁺) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) by acting as an activator of the Nrf2/ARE cascade. We showed that TQ significantly reduced MPP⁺-mediated cell death and apoptosis. Moreover, TQ significantly elevated the nuclear translocation of Nrf2 and significantly increased the subsequent expression of antioxidative genes such as Heme oxygenase 1 (HO-1), quinone oxidoreductase (NQO1) and Glutathione-S-Transferase (GST). The application of siRNA to silence Nrf2 led to an abolishment in the protective effects of TQ. We also found that the intraperitoneal injection of TQ into a rodent model of PD ameliorated oxidative stress and effectively mitigated nigrostriatal dopaminergic degeneration by activating the Nrf2-ARE pathway. However, these effects were inhibited by the injection of a lentivirus wrapped Nrf2 siRNA (siNrf2). Collectively, these findings suggest that TQ alleviates progressive dopaminergic neuropathology by activating the Nrf2/ARE signaling cascade and by attenuating oxidative stress, thus demonstrating that TQ is a potential novel drug candidate for the treatment of PD.

The fate of the brain cholinergic neurons in neurodegenerative diseases

The aims of this review are: 1) to describe which cholinergic neurons are affected in brain neurodegenerative diseases leading to dementia; 2) to discuss the possible causes of the degeneration of the cholinergic neurons, 3) to summarize the functional consequences of the cholinergic deficit. The brain cholinergic system is basically constituted by three populations of phenotypically similar neurons forming a series of basal forebrain nuclei, the midpontine nuclei and a large population of striatal interneurons. In Alzheimer's disease there is an extensive loss of forebrain cholinergic neurons accompanied by a reduction of the cholinergic fiber network of the cortical mantel and hippocampus. The midpontine cholinergic nuclei are spared. The same situation occurs in the corticobasal syndrome and dementia following alcohol abuse and traumatic brain injury. Conversely, in Parkinson's disease, the midpontine nuclei degenerate, together with the dopaminergic nuclei, reducing the cholinergic input to thalamus and forebrain whereas the forebrain cholinergic neurons are spared. In Parkinson's disease with dementia, Lewis Body Dementia and Parkinsonian syndromes both groups of forebrain and midpontine cholinergic nuclei degenerate. In Huntington's disease a dysfunction of the striatal cholinergic interneurons without cell loss takes place. The formation and accumulation of misfolded proteins such as β-amyloid oligomers and plaques, tau protein tangles and α-synuclein clumps, and aggregated mutated huntingtin play a crucial role in the neuronal degeneration by direct cellular toxicity of the misfolded proteins and through the toxic compounds resulting from an extensive inflammatory reaction. Evidences indicate that β-amyloid disrupts NGF metabolism causing the degeneration of the cholinergic neurons which depend on NGF for their survival, namely the forebrain cholinergic neurons, sparing the midpontine and striatal neurons which express no specific NGF receptors. It is feasible that the latter cholinergic neurons may be damaged by direct toxicity of tau, α-synuclein and inflammations products through mechanisms not fully understood. Attention and learning and memory impairment are the functional consequences of the forebrain cholinergic neuron dysfunction, whereas the loss of midpontine cholinergic neurons results primarily in motor and sleep disturbances.