Global Epidemiology of Movement Disorders: Rare or Underdiagnosed?

MiR-29a efficiently suppresses the generation of reactive oxygen species and α-synuclein in a cellular model of Parkinson's disease by potentially targeting GSK-3β

MicroRNA-29a (miR-29a) has been suggested to serve a potential protective function against Parkinson's disease (PD); however, the exact molecular mechanisms remain elusive. This study explored the protective role of miR-29a in a cellular model of PD using SH-SY5Y cell lines through iTRAQ-based quantitative proteomic and biochemistry analysis. The findings showed that using a miR-29a mimic in SH-SY5Y cells treated with 1-methyl-4-phenylpyridinium (MPP+) significantly decreased cell death and increased mitochondrial membrane potential. It also reduced mitochondrial reactive oxygen species (ROS) and the production of α-synuclein. Subsequent heatmap analysis using iTRAQ-based quantitative proteomics revealed remarkably contrasting protein expression profiles for 882 genes when comparing the groups treated with miR-29a mimic plus MPP + against the control group treated solely with MPP+. The KEGG pathway analysis of these 882 genes indicated the substantial role of miR-29a in the PD pathway (P = 1.58x10-5) and highlighted its function in mitochondrial genes. Furthermore, treatment with a miR-29a mimic in SH-SY5Y cells reduced the levels of GSK-3β, phosphorylated GSK-3β, and cleaved caspase-7 following exposure to MPP+. The miR-29a mimic also upregulated the expressions of α-synuclein clearance proteins FYCO1 and Rab7 in this cellular PD model, thereby inhibiting the production of α-synuclein. Luciferase activity analysis confirmed the specific binding of miR-29a to the 3' untranslated region (3'UTR) of GSK-3β, leading to its repression. Our findings demonstrated miR-29a's neuroprotective role in mitochondrial function and highlighted its potential to inhibit ROS and α-synuclein production, offering possible therapeutic avenues for PD treatment.

Myasthenia gravis concurrent with Parkinson's disease in a Spanish cohort. Causation or correlation?

BACKGROUND

Comorbidity between myasthenia gravis (MG) and other autoimmune diseases is well-documented. However, concurrent MG and Parkinson's disease (PD) have rarely been described. This concurrence has mostly been considered coincidental in cases reported to date.

MATERIAL/METHODS

We characterized patients with concurrent MG and PD within a cohort of 631 MG patients by gender, age, MGFA class, quantitative MG score at diagnosis, UPDRS score at diagnosis, and the DaTSCAN uptake pattern, to determine the frequency and the phenotype of individuals with these two concurrent entities. Meta-analysis of cases in the literature was used for comparison with our series.

RESULTS

Eighteen cases were identified in which the two diseases were concurrent. The major characteristics of the phenotype are male prevalence, late-onset MG, and frequent initial symptoms of dropped head and oculobulbar involvement. DAT confirmed reduced bilateral uptake in eleven patients and reduced unilateral uptake in the others.

CONCLUSIONS

To our knowledge, this is the largest reported series of concurrent MG and PD. This concurrence is more common than expected (2.85%). Either MG or PD may appear first. We found no iatrogenic relationship for the order of appearance. The overlapping of symptoms sometimes leads physicians to overlook the second disease, instead viewing it as a deterioration of the first. This study describes patients with well-documented diagnoses of both MG and PD, thus providing further indications of a shared etiology of these two diseases. Prospective studies including genetic, immunological, and environmental analysis are necessary to identify possible common pathogenic mechanisms.

MRI-Guided Focused Ultrasound for the Treatment of Dystonia: A Narrative Review

Contemporary surgical management of dystonia includes neuromodulation via deep brain stimulation (DBS) or ablative techniques such as radiofrequency (RF) ablation. MRI-guided focused ultrasound (MRgFUS) is an emerging modality that uses high-intensity ultrasound to precisely ablate targets in the brain; this is incisionless, potentially avoiding the surgical risks of a burr hole and transcortical tract to reach the anatomical target. There is some evidence of efficacy in essential tremor and Parkinson's disease (PD), but, to date, there is no study aggregating the evidence of MRgFUS in dystonia. In this narrative review, we searched Medline, Embase, CINAHL, EBSCO, and ClinicalTrials.gov for primary studies and clinical trials on MRgFUS in the treatment of dystonia. Data were analyzed concerning dystonia phenotype, reported outcomes, and complications. PD-related dystonia was also included within the scope of the review. Using our search criteria, six articles on the use of MRgFUS in adult dystonia and three articles on the use of FUS in dystonia in PD were included. Four trials on the use of FUS in dystonia were also found on ClinicalTrials.gov, one of which was completed in December 2013. All included studies showed evidence of symptomatic improvement, mostly in focal hand dystonia; improvements were also found in dystonia-associated tremor, cervicobrachial dystonia, and dystonia-associated chronic neuropathic pain as well as PD-related dystonia. Reported complications included transient neurological deficits and persistent arm pain in one study. However, the evidence is limited to level-4 case series at present. MRgFUS is an emerging modality that appears to be safe and effective, particularly in focal hand dystonia, without major adverse effects. However, the quality of evidence is low at present, and long-term outcomes are unknown. High-quality prospective studies comparing MRgFUS to other surgical techniques will be useful in determining its role in the management of dystonia.

Advances in targeting neurotransmitter systems in dystonia

Dystonia is characterised as uncontrolled, often painful involuntary muscle contractions that cause abnormal postures and repetitive or twisting movements. These movements can be continuous or sporadic and affect different parts of the body and range in severity. Dystonia and its related conditions present a huge cause of neurological morbidity worldwide. Although therapies are available, achieving optimal symptom control without major unwanted effects remains a challenge. Most pharmacological treatments for dystonia aim to modulate the effects of one or more neurotransmitters in the central nervous system, but doing so effectively and with precision is far from straightforward. In this chapter we discuss the physiology of key neurotransmitters, including dopamine, noradrenaline, serotonin (5-hydroxytryptamine), acetylcholine, GABA, glutamate, adenosine and cannabinoids, and their role in dystonia. We explore the ways in which existing pharmaceuticals as well as novel agents, currently in clinical trial or preclinical development, target dystonia, and their respective advantages and disadvantages. Finally, we discuss current and emerging genetic therapies which may be used to treat genetic forms of dystonia.