Brain stimulation in Huntington's disease

Translational Approach using Advanced Therapy Medicinal Products for Huntington's Disease

Current therapeutic approaches for Huntington's disease (HD) focus on symptomatic treatment. Therefore, the unavailability of efficient disease-modifying medicines is a significant challenge. Regarding the molecular etiology, targeting the mutant gene or advanced translational steps could be considered promising strategies. The evidence in gene therapy suggests various molecular techniques, including knocking down mHTT expression using antisense oligonucleotides and small interfering RNAs and gene editing with zinc finger proteins and CRISPR-Cas9-based techniques. Several post-transcriptional and post-translational modifications have also been proposed. However, the efficacy and long-term side effects of these modalities have yet to be verified. Currently, cell therapy can be employed in combination with conventional treatment and could be used for HD in which the structural and functional restoration of degenerated neurons can occur. Several animal models have been established recently to develop cell-based therapies using renewable cell sources such as embryonic stem cells, induced pluripotent stem cells, mesenchymal stromal cells, and neural stem cells. These models face numerous challenges in translation into clinics. Nevertheless, investigations in Advanced Therapy Medicinal Products (ATMPs) open a promising window for HD research and their clinical application. In this study, the ATMPs entry pathway in HD management was highlighted, and their advantages and disadvantages were discussed.

Harnessing Brainwave Entrainment: A Non-invasive Strategy To Alleviate Neurological Disorder Symptoms

From 1990-2019, the burden of neurological disorders varied considerably across countries and regions. Psychiatric disorders, often emerging in early to mid-adulthood, are linked to late-life neurodegenerative diseases like Alzheimer's disease and Parkinson's disease. Individuals with conditions such as Major Depressive Disorder, Anxiety Disorder, Schizophrenia, and Bipolar Disorder face up to four times higher risk of developing neurodegenerative disorders. Contrarily, 65 % of those with neurodegenerative conditions experience severe psychiatric symptoms during their illness. Further, the limitation of medical resources continues to make this burden a significant global and local challenge. Therefore, brainwave entrainment provides therapeutic avenues for improving the symptoms of diseases. Brainwaves are rhythmic oscillations produced either spontaneously or in response to stimuli. Key brainwave patterns include gamma, beta, alpha, theta, and delta waves, yet the underlying physiological mechanisms and the brain's ability to shift between these dynamic states remain areas for further exploration. In neurological disorders, brainwaves are often disrupted, a phenomenon termed "oscillopathy". However, distinguishing these impaired oscillations from the natural variability in brainwave activity across different regions and functional states poses significant challenges. Brainwave-mediated therapeutics represents a promising research field aimed at correcting dysfunctional oscillations. Herein, we discuss a range of non-invasive techniques such as non-invasive brain stimulation (NIBS), neurologic music therapy (NMT), gamma stimulation, and somatosensory interventions using light, sound, and visual stimuli. These approaches, with their minimal side effects and cost-effectiveness, offer potential therapeutic benefits. When integrated, they may not only help in delaying disease progression but also contribute to the development of innovative medical devices for neurological care.

Understanding Osaka mutation polymorphic Aβ fibril response to static and oscillating electric fields: insights from computational modeling

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder, impacting millions of individuals worldwide. Among its defining characteristics is the accumulation of senile plaques within the brain's gray matter, formed through the self-assembly of misfolded proteins contributing to the progressive symptoms of AD. This study investigates a polymorphic Aβ fibril under static and oscillating electric fields using molecular dynamics simulation. Specifically, we utilized a polymorphic fibrillar complex composed of two intertwined pentamer-strands of the Aβ1-40 peptide with the Osaka mutation (E22Δ), known for its toxicity and stable structure. Our findings demonstrate that a 0.3 and 0.4 V/nm electric field combined with a 0.20 GHz frequency effectively disrupts the polymorphic conformation of Aβ fibrils. Furthermore, we elucidate the molecular mechanisms underlying this disruption, providing insights into the potential therapeutic use of oscillating electric fields for AD. This research offers valuable insights into novel therapeutic approaches for combating AD pathology.

Transcranial magnetic stimulation in animal models of neurodegeneration

Brain stimulation techniques offer powerful means of modulating the physiology of specific neural structures. In recent years, non-invasive brain stimulation techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation, have emerged as therapeutic tools for neurology and neuroscience. However, the possible repercussions of these techniques remain unclear, and there are few reports on the incisive recovery mechanisms through brain stimulation. Although several studies have recommended the use of non-invasive brain stimulation in clinical neuroscience, with a special emphasis on TMS, the suggested mechanisms of action have not been confirmed directly at the neural level. Insights into the neural mechanisms of non-invasive brain stimulation would unveil the strategies necessary to enhance the safety and efficacy of this progressive approach. Therefore, animal studies investigating the mechanisms of TMS-induced recovery at the neural level are crucial for the elaboration of non-invasive brain stimulation. Translational research done using animal models has several advantages and is able to investigate knowledge gaps by directly targeting neuronal levels. In this review, we have discussed the role of TMS in different animal models, the impact of animal studies on various disease states, and the findings regarding brain function of animal models after TMS in pharmacology research.

Medical, Surgical, and Genetic Treatment of Huntington Disease

Huntington disease, a neurodegenerative disease characterized by progressive motor, behavioral, and cognitive decline, is caused by a CAG trinucleotide repeat expansion in the huntingtin gene on chromosome 4. Current treatments target symptom management because there are no disease-modifying therapies at this time. Investigation of RNA-based and DNA-based treatment strategies are emerging and hold promise of possible future disease-modifying therapy.

Treatment options for chorea

INTRODUCTION

Chorea is defined as jerk-like movements that move randomly from one body part to another. It is due to a variety of disorders and although current symptomatic therapy is quite effective there are few etiology- or pathogenesis-targeted therapies. The aim of this review is to summarize our own experience and published evidence in the treatment of chorea. Areas covered: After evaluating current guidelines and clinical practices for chorea of all etiologies, PubMed was searched for the most recent clinical trials and reviews using the term 'chorea' cross referenced with specific drug names. Expert commentary: Inhibitors of presynaptic vesicular monoamine transporter type 2 (VMAT2) that cause striatal dopamine depletion, such as tetrabenazine, deutetrabenazine, and valbenazine, are considered the treatment of choice in patients with chorea. Some clinicians also use dopamine receptor blockers (e.g. antipsychotics) and other drugs, including anti-epileptics and anti-glutamatargics. 'Dopamine stabilizers' such as pridopidine and other experimental drugs are currently being investigated in the treatment of chorea. Deep brain stimulation is usually reserved for patients with disabling chorea despite optimal medical therapy.

Deep Brain Stimulation in Huntington's Disease-Preliminary Evidence on Pathophysiology, Efficacy and Safety

Huntington's disease (HD) is one of the most disabling degenerative movement disorders, as it not only affects the motor system but also leads to cognitive disabilities and psychiatric symptoms. Deep brain stimulation (DBS) of the pallidum is a promising symptomatic treatment targeting the core motor symptom: chorea. This article gives an overview of preliminary evidence on pathophysiology, safety and efficacy of DBS in HD.

Combined Invasive Subcortical and Non-invasive Surface Neurophysiological Recordings for the Assessment of Cognitive and Emotional Functions in Humans

In spite of the success in applying non-invasive electroencephalography (EEG), magneto-encephalography (MEG) and functional magnetic resonance imaging (fMRI) for extracting crucial information about the mechanism of the human brain, such methods remain insufficient to provide information about physiological processes reflecting cognitive and emotional functions at the subcortical level. In this respect, modern invasive clinical approaches in humans, such as deep brain stimulation (DBS), offer a tremendous possibility to record subcortical brain activity, namely local field potentials (LFPs) representing coherent activity of neural assemblies from localized basal ganglia or thalamic regions. Notwithstanding the fact that invasive approaches in humans are applied only after medical indication and thus recorded data correspond to altered brain circuits, valuable insight can be gained regarding the presence of intact brain functions in relation to brain oscillatory activity and the pathophysiology of disorders in response to experimental cognitive paradigms. In this direction, a growing number of DBS studies in patients with Parkinson's disease (PD) target not only motor functions but also higher level processes such as emotions, decision-making, attention, memory and sensory perception. Recent clinical trials also emphasize the role of DBS as an alternative treatment in neuropsychiatric disorders ranging from obsessive compulsive disorder (OCD) to chronic disorders of consciousness (DOC). Consequently, we focus on the use of combined invasive (LFP) and non-invasive (EEG) human brain recordings in assessing the role of cortical-subcortical structures in cognitive and emotional processing trough experimental paradigms (e.g. speech stimuli with emotional connotation or paradigms of cognitive control such as the Flanker task), for patients undergoing DBS treatment.