Mitochondrial enhancement for neurodegenerative movement disorders: a systematic review of trials involving creatine, coenzyme Q10, idebenone and mitoquinone

Illusions of Self-Motion during Magnetic Resonance-Guided Focused Ultrasound Thalamotomy for Tremor

OBJECTIVE

Brain networks mediating vestibular perception of self-motion overlap with those mediating balance. A systematic mapping of vestibular perceptual pathways in the thalamus may reveal new brain modulation targets for improving balance in neurological conditions.

METHODS

Here, we systematically report how magnetic resonance-guided focused ultrasound surgery of the nucleus ventralis intermedius of the thalamus commonly evokes transient patient-reported illusions of self-motion. In 46 consecutive patients, we linked the descriptions of self-motion to sonication power and 3-dimensional (3D) coordinates of sonication targets. Target coordinates were normalized using a standard atlas, and a 3D model of the nucleus ventralis intermedius and adjacent structures was created to link sonication target to the illusion.

RESULTS

A total of 63% of patients reported illusions of self-motion, which were more likely with increased sonication power and with targets located more inferiorly along the rostrocaudal axis. Higher power and more inferiorly targeted sonications increased the likelihood of experiencing illusions of self-motion by 4 and 2 times, respectively (odds ratios = 4.03 for power, 2.098 for location).

INTERPRETATION

The phenomenon of magnetic vestibular stimulation is the most plausible explanation for these illusions of self-motion. Temporary unilateral modulation of vestibular pathways (via magnetic resonance-guided focused ultrasound) unveils the central adaptation to the magnetic field-induced peripheral vestibular bias, leading to an explicable illusion of motion. Consequently, systematic mapping of vestibular perceptual pathways via magnetic resonance-guided focused ultrasound may reveal new intracerebral targets for improving balance in neurological conditions. ANN NEUROL 2024;96:121-132.

Hereditary Ataxias: From Bench to Clinic, Where Do We Stand?

Cerebellar ataxias are a wide heterogeneous group of movement disorders. Within this broad umbrella of diseases, there are both genetics and sporadic forms. The clinical presentation of these conditions can exhibit a diverse range of symptoms across different age groups, spanning from pure cerebellar manifestations to sensory ataxia and multisystemic diseases. Over the last few decades, advancements in our understanding of genetics and molecular pathophysiology related to both dominant and recessive ataxias have propelled the field forward, paving the way for innovative therapeutic strategies aimed at preventing and arresting the progression of these diseases. Nevertheless, the rarity of certain forms of ataxia continues to pose challenges, leading to limited insights into the etiology of the disease and the identification of target pathways. Additionally, the lack of suitable models hampers efforts to comprehensively understand the molecular foundations of disease's pathophysiology and test novel therapeutic interventions. In the following review, we describe the epidemiology, symptomatology, and pathological progression of hereditary ataxia, including both the prevalent and less common forms of these diseases. Furthermore, we illustrate the diverse molecular pathways and therapeutic approaches currently undergoing investigation in both pre-clinical studies and clinical trials. Finally, we address the existing and anticipated challenges within this field, encompassing both basic research and clinical endeavors.

Neuromodulatory effect of 4-(methylthio)butyl isothiocyanate against 3-nitropropionic acid induced oxidative impairments in human dopaminergic SH-SY5Y cells via BDNF/CREB/TrkB pathway

Mitochondrial impairment, energetic crisis and elevated oxidative stress have been demonstrated to play a pivotal role in the pathological processes of Huntington's disease (HD). 3-Nitropropionic acid (3-NPA) is a natural neurotoxin that mimics the neurological dysfunctions, mitochondrial impairments and oxidative imbalance of HD. The current investigation was undertaken to demonstrate the neuroprotective effect of 4-(methylthio)butyl isothiocyanate (4-MTBITC) against the 3-NPA induced neurotoxicity in human dopaminergic SH-SY5Y cells. The experimental evidence of oxidative DNA damage by 3-NPA was elucidated by pBR322 DNA nicking assay. In contrast, the 4-MTBITC considerably attenuated the DNA damage, suggesting its free radical scavenging action against 3-NPA and Fenton's reagent. The dose and time-dependent increase of 3-NPA revealed its neurotoxic dose as 0.5 mM after 24 h of treatment of SH-SY5Y cells in MTT assay. In order to determine the optimal dose at which 4-MTBITC protects cell death, the 3-NPA (IC₅₀) induced cells were pretreated with different concentrations of 4-MTBITC for 1 h. The neuroprotective dose of 4-MTBITC against 3-NPA was found to be 0.25 μM. Additionally, the elevated GSH levels in cells treated with 4-MTBITC indicate its propensity to eliminate reactive species generated as a result of 3-NPA-induced mitochondrial dysfunction. Likewise, it was determined through microscopic and flow cytometric experiments that 3-NPA's induced overproduction of reactive species and a decline in mitochondrial membrane potential (MMP) could be efficiently prevented by pre-treating cells with 4-MTBITC. To elucidate the underlying molecular mechanism, the RT-qPCR analysis revealed that the pre-treatment of 4-MTBITC effectively protected neuronal cells against 3-NPA-induced cell death by preventing Caspase-3 activation, Brain-derived neurotrophic factor (BDNF) upregulation, activation of cAMP response element-binding protein (CREB) and Nrf2 induction. Together, our findings lend credence to the idea that pre-treatment with 4-MTBITC reduced 3-NPA-induced neurotoxicity by lowering redox impairment, apoptotic state, and mitochondrial dysfunction. The present work, in conclusion, presented the first proof that the phytoconstituent 4-MTBITC supports the antioxidant system, BDNF/TrkB/CREB signaling, and neuronal survival in dopaminergic SH-SY5Y cells against 3-NPA-induced oxidative deficits.

Mitochondria-Targeted Antioxidants, an Innovative Class of Antioxidant Compounds for Neurodegenerative Diseases: Perspectives and Limitations

Neurodegenerative diseases comprise a wide spectrum of pathologies characterized by progressive loss of neuronal functions and structures. Despite having different genetic backgrounds and etiology, in recent years, many studies have highlighted a point of convergence in the mechanisms leading to neurodegeneration: mitochondrial dysfunction and oxidative stress have been observed in different pathologies, and their detrimental effects on neurons contribute to the exacerbation of the pathological phenotype at various degrees. In this context, increasing relevance has been acquired by antioxidant therapies, with the purpose of restoring mitochondrial functions in order to revert the neuronal damage. However, conventional antioxidants were not able to specifically accumulate in diseased mitochondria, often eliciting harmful effects on the whole body. In the last decades, novel, precise, mitochondria-targeted antioxidant (MTA) compounds have been developed and studied, both in vitro and in vivo, to address the need to counter the oxidative stress in mitochondria and restore the energy supply and membrane potentials in neurons. In this review, we focus on the activity and therapeutic perspectives of MitoQ, SkQ1, MitoVitE and MitoTEMPO, the most studied compounds belonging to the class of MTA conjugated to lipophilic cations, in order to reach the mitochondrial compartment.

CoQ10 and Resveratrol Effects to Ameliorate Aged-Related Mitochondrial Dysfunctions

Mitochondria participate in the maintenance of cellular homeostasis. Firstly, mitochondria regulate energy metabolism through oxidative phosphorylation. In addition, they are involved in cell fate decisions by activating the apoptotic intrinsic pathway. Finally, they work as intracellular signaling hubs as a result of their tight regulation of ion and metabolite concentrations and other critical signaling molecules such as ROS. Aging is a multifactorial process triggered by impairments in different cellular components. Among the various molecular pathways involved, mitochondria are key regulators of longevity. Indeed, mitochondrial deterioration is a critical signature of the aging process. In this scenario, we will focus specifically on the age-related decrease in CoQ levels, an essential component of the electron transport chain (ETC) and an antioxidant, and how CoQ supplementation could benefit the aging process. Generally, any treatment that improves and sustains mitochondrial functionality is a good candidate to counteract age-related mitochondrial dysfunctions. In recent years, heightened attention has been given to natural compounds that modulate mitochondrial function. One of the most famous is resveratrol due to its ability to increase mitochondrial biogenesis and work as an antioxidant agent. This review will discuss recent clinical trials and meta-analyses based on resveratrol and CoQ supplementation, focusing on how these compounds could improve mitochondrial functionality during aging.

Efficacy of idebenone in the Treatment of iRBD into Synucleinopathies (EITRS): rationale, design, and methodology of a randomized, double-blind, multi-center clinical study

Background

As the strongest prodromal marker of α-synuclein-specific neurodegeneration, idiopathic REM sleep behavior disorder (iRBD) is becoming a focus of interest in disease-modifying therapy. Idebenone has been widely portrayed as a potent antioxidant targeting mitochondrial dysfunction. Previous study has identified the effect of idebenone on Parkinson's disease with promising outcomes by regulating mitophagy. A novel indication of idebenone should be highlighted in iRBD population.

Methods

The EITRS study is a randomized, double-blind, multi-center clinical study assessing the efficacy and safety of idebenone in the treatment of iRBD into synucleinopathies. One hundred forty-two patients (aged 40–75 years old) with clinically diagnosed iRBD are planned to be recruited with 80% statistical power and randomly assigned to idebenone (30 mg each time, three times a day) or matching placebo orally for 5 years. The assessment of rating scales, blood testing and neuroimaging examinations will be conducted at baseline, the 1st, 3rd and 5th year of follow-up. The primary efficacy endpoint is the 5-year conversion rate in patients with iRBD. The secondary endpoint is the safety and tolerability of idebenone in the treatment of iRBD. The study has been launched in July 2020.

Discussion

This is the first prospective study designed to identify the efficacy and safety of idebenone on the treatment of iRBD into synucleinopathies. The current results are expected to promote the development of evidence-based recommendations for the management of patients with iRBD. Furthermore, we hope to provide insights on a possible disease-modifying approach with robust evidence.

Trial Registration

Clinicaltrials.gov, identifier: NCT 04534023.

Idebenone improves motor dysfunction, learning and memory by regulating mitophagy in MPTP-treated mice

The progression of Parkinson’s disease (PD) is often accompanied by the loss of substantia nigra dopaminergic neurons, mitophagy damage, learning, and memory impairment. Idebenone is a therapeutic drug that targets the mitochondria of neurodegenerative diseases, but its role in Parkinson’s disease and its pathological mechanism are still unclear. The purpose of this study was to investigate whether idebenone could improve behavioral disorders, especially motor, learning, and memory disorders, in mouse PD models and to explore its molecular mechanism. In the present study, C57BL-6 mice underwent intraperitoneal injection of MPTP (30 mg/kg) once a day for five consecutive days. Then, a 200 mg/kg dose was given as a single daily gavage of idebenone dissolved in water for 21 days after the successful establishment of the subacute MPTP model. Motor, learning, and memory were measured by a water maze and a rotarod test. Our results showed that idebenone could reduce MPTP-induced dopaminergic neuron damage and improve movement disorders, memory, and learning ability, which may be associated with upregulating mitochondrial autophagy-related outer membrane proteins VDAC1 and BNIP3 and activating the Parkin/PINK1 mitochondrial autophagy pathway. To confirm whether idebenone promotes the smooth progression of autophagy, we used eGFP-mCherry-LC3 mice to construct a subacute model of Parkinson’s disease and found that idebenone can increase autophagy in dopaminergic neurons in Parkinson’s disease. In summary, our results confirm that idebenone can regulate the expression of the mitochondrial outer membrane proteins VDAC1 and BNIP3, activate Parkin/PINK1 mitophagy, promote the degradation of damaged mitochondria, reduce dopaminergic neuron damage, and improve behavioral disorders in Parkinson’s disease mice.

Cytotoxicity and Mitochondrial Effects of Phenolic and Quinone-Based Mitochondria-Targeted and Untargeted Antioxidants on Human Neuronal and Hepatic Cell Lines: A Comparative Analysis

Mitochondriotropic antioxidants (MC3, MC6.2, MC4 and MC7.2) based on dietary antioxidants and analogs (caffeic, hydrocaffeic, trihydroxyphenylpropanoic and trihydroxycinnamic acids) were developed. In this study, we evaluate and compare the cytotoxicity profile of novel mitochondria-targeted molecules (generally known as MitoCINs) on human HepG2 and differentiated SH-SY5Y cells with the quinone-based mitochondria-targeted antioxidants MitoQ and SkQ1 and with two non-targeted antioxidants, resveratrol and coenzyme Q10 (CoQ10). We further evaluate their effects on mitochondrial membrane potential, cellular oxygen consumption and extracellular acidification rates. Overall, MitoCINs derivatives reduced cell viability at concentrations about six times higher than those observed with MitoQ and SkQ1. A toxicity ranking for both cell lines was produced: MC4 < MC7.2 < MC3 < MC6.2. These results suggest that C-6 carbon linker and the presence of a pyrogallol group result in lower cytotoxicity. MC3 and MC6.2 affected the mitochondrial function more significantly relative to MitoQ, SkQ1, resveratrol and CoQ10, while MC4 and MC7.2 displayed around 100-1000 times less cytotoxicity than SkQ1 and MitoQ. Based on the mitochondrial and cytotoxicity cellular data, MC4 and MC7.2 are proposed as leads that can be optimized to develop safe drug candidates with therapeutic application in mitochondrial oxidative stress-related diseases.

Nutritional aspects in Parkinson's disease

The links between diet and Parkinson's disease (PD) are unclear and incomprehensible. However, numerous studies have demonstrated the correlation between diet, nutrients and health condition in PD patients. They indicate the possibility of management of the disease, which might be possible through nutrition. Pharmaceutical treatment as well as a complementary holistic approach to the patients should be considered. It is of critical importance to understand how the diet and nutrients might influence PD. A better understanding of the relationship between diet and PD could help to better manage the disease explain promising therapeutic approaches, minimize motor and nonmotor symptoms and disease progression based on a personalized diet. In this review, the recent literature on the observed nutrition disorders and the possible role of diet and nutrients in the prevention and potential regression of PD, as well as dietary interventions and supplementation used to manage the disease is revised.

Idebenone Ameliorates Rotenone-Induced Parkinson's Disease in Rats Through Decreasing Lipid Peroxidation

Oxidative stress is considered one of the mechanisms responsible for neurodegenerative diseases, especially for Parkinson's disease. Since oxidative stress causes pathological changes in neuronal structures antioxidant compounds gained significant attention the last decades. Although several antioxidant compounds showed neuroprotective actions in Parkinson's disease models, only a few of them demonstrated protective effects against loss of striatal dopaminergic neurons. Idebenone is an analog of the well-known antioxidant compound coenzyme Q10 (CoQ10). Clinical safety of idebenone is well described, and due to its high antioxidant capacity currently used to treat Freidrich's ataxia and Alzheimer's disease. Like Parkinson's disease, these diseases are characterized by oxidative stress and impaired mitochondrial balance in neurons. However, knowledge about the effects of idebenone on Parkinson's disease is limited. Therefore, in this study we aimed to investigate and delineate the possible effects of idebenone in rotenone-induced Parkinson's disease models. Idebenone (200 mg/kg, p.o.) inhibited the decrease of striatal expression of NAD(P)H dehydrogenase[quinone]-1, which is an essential element for mitochondrial respiration. Idebenone decreased the striatal levels of the lipid peroxidation products and increased the expression of glutathione peroxidase-4 (GPx-4), which is primarily known for lipid peroxidation and ferroptosis. Furthermore, idebenone mitigated motor impairment and increased tyrosine hydroxylase-positive neuron survival. Together our results thus indicate that that idebenone has protective effects against a rotenone insult with pleiotropic actions on the cellular oxidative enzymes and lipid peroxidation.

Friedreich Ataxia: current state-of-the-art, and future prospects for mitochondrial-focused therapies

Friedreich's Ataxia is an autosomal recessive genetic disease causing the defective gene product, frataxin. A body of literature has been focused on the attempts to counteract frataxin deficiency and the consequent iron imbalance, in order to mitigate the disease-associated pro-oxidant state and clinical course. The present mini review is aimed at evaluating the basic and clinical reports on the roles and the use of a set of iron chelators, antioxidants and some cofactors involved in the key mitochondrial functions. Extensive literature has focused on the protective roles of iron chelators, coenzyme Q10 and analogs, and vitamin E, altogether with varying outcomes in clinical studies. Other studies have suggested mitoprotective roles for other mitochondrial cofactors, involved in Krebs cycle, such as alpha-lipoic acid and carnitine, involved in acyl transport across the mitochondrial membrane. A body of evidence points to the strong antioxidant properties of these cofactors, and to their potential contribution in mitoprotective strategies in Friedreich's Ataxia clinical evolution. Thus, we suggest the rationale for planning combination strategies based on the 3 mitochondrial cofactors and of some antioxidants and iron binders as mitoprotective cocktails in Friedreich Ataxia patients, calling attention to clinical practitioners of the importance to implement clinical trials.

Advances of Mechanisms-Related Metabolomics in Parkinson's Disease

Parkinson’s disease (PD) is a multifactorial disorder characterized by progressively debilitating dopaminergic neurodegeneration in the substantia nigra and the striatum, along with various metabolic dysfunctions and molecular abnormalities. Metabolomics is an emerging study and has been demonstrated to play important roles in describing complex human diseases by integrating endogenous and exogenous sources of alterations. Recently, an increasing amount of research has shown that metabolomics profiling holds great promise in providing unique insights into molecular pathogenesis and could be helpful in identifying candidate biomarkers for clinical detection and therapies of PD. In this review, we briefly summarize recent findings and analyze the application of molecular metabolomics in familial and sporadic PD from genetic mutations, mitochondrial dysfunction, and dysbacteriosis. We also review metabolic biomarkers to assess the functional stage and improve therapeutic strategies to postpone or hinder the disease progression.

Placebo response in degenerative cerebellar ataxias: a descriptive review of randomized, placebo-controlled trials

Placebo response in degenerative cerebellar ataxias (CAs) has never been studied despite the large number of randomized controlled trials (RCTs) that have been conducted. In this descriptive review, we aimed to examine the placebo response in patients with CAs. We performed a literature search on PubMed for RCTs on CAs that were published from 1977 to January 2020 and collected data on the changes from the baseline to the endpoint on various objective ataxia-associated clinical rating scales. We reviewed 56 clinical trials, finally including 35 parallel-group studies and excluding 21 cross-over studies. The included studies were categorized as follows: (1) studies showing significant improvements in one or more ataxia scales in the placebo groups (n = 3); (2) studies reporting individual placebo responders with improvements in one or more ataxia scales in the placebo groups (n = 5)-the overall proportion of placebo responders was 31.9%; (3) studies showing mean changes in the direction of improvement in at least one ataxia scale in the placebo groups, though not statistically significant (n = 19); (4) studies showing no placebo response in any of the ataxia scales in the placebo groups (n = 4); (5) studies where data on the placebo groups were unavailable (n = 9). This review demonstrated the placebo response in patients with CAs on various objective ataxia scales. Our study emphasizes that the placebo response should be considered when designing, analyzing, and interpreting clinical trials and in clinical practice in CA patients.

Update on the Treatment of Ataxia: Medication and Emerging Therapies

While rehabilitation therapies always help patients with ataxia, there are currently no FDA-approved treatments for ataxia. Medications are available to treat symptoms that may complicate an ataxic illness, e.g., tremor, myoclonus, dystonia, and rigidity, which are discussed elsewhere in this volume. Spasticity, pain, fatigue, depression, sleep disturbances, cognitive decline, and bowel and bladder dysfunction, if they occur, all have multiple available drugs and therapies for symptomatic use. There is also an extensive literature on off-label uses of various medications to improve imbalance. The pipeline of emerging therapies for symptomatic and possible disease-modifying management of ataxia gives hope that we will soon see the first of many FDA-approved drugs for ataxic illnesses.

Teaching the basics of repurposing mitochondria-targeted drugs: From Parkinson's disease to cancer and back to Parkinson's disease

Parkinson's disease (PD) and cancer share common mutations in mitochondrial proteins: Parkin and PINK1. The overlapping of genes involved in PD and cancer implies that the two diseases might share a common pathogenic mechanism. There are other compelling rationales for a mechanistic link between these diseases. Mitochondria and autophagy/mitophagy are emerging as therapeutic targets in PD and cancer: Ongoing research in our laboratories has shown that, when administered early, mitochondria-targeted agents afford neuroprotection in preclinical mice models of PD. Also, we discovered that mitochondria-targeted drugs inhibit tumor cell proliferation. We propose that mitochondrial targeting stimulates conservation of cellular energy critical for neuronal cell survival, whereas the energy conservation mechanism inhibits proliferation of cancer cells by depriving the energy necessary for cancer cell growth. We propose a promising drug repurposing strategy involving mitochondria-targeted drugs synthesized from naturally occurring molecules and FDA-approved drugs that are relatively nontoxic in both PD and cancer. These compounds have been shown to induce various cellular signaling pathways for autophagy/mitophagy, anti-inflammatory, and immunomodulatory effects that are implicated as therapeutic mechanisms in PD and cancer.

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Targeting mitochondria in cancer and PD could be a useful drug repurposing strategy.

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Modification of natural compounds with TPP+targets mitochondria.

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Mitochondria-targeted agents induce multiple cell signaling mechanisms.

Efficacy and safety of valproic acid in dementia: A systematic review with meta-analysis

INTRODUCTION

The neuroprotective effect of valproic acid has been observed in the animal models of neurodegeneration, which suggests it as a potential candidate for clinical trials. In this paper, we aimed to systematically analyze the efficacy and safety of valproic acid in the treatment of dementia.

METHODS

We searched the electronic databases PubMed, EMBASE, CINAHL, Cochrane Library and China National Knowledge Infrastructure until March 2020 for the eligible randomized controlled trials, as well as the unpublished and ongoing trials. We pooled the results using a random-effects model.

RESULTS

We included seven studies with 770 randomized patients with dementia, which compared valproic acid with placebo. Indeed, there were no significant differences found in the scores of Mini-mental State Examination, Cohen-Mansfield Agitation Inventory and number of patients with adverse events. Valproic acid is generally well-tolerated in patients with dementia, even in long-term therapy for 24 months.

CONCLUSION

Insufficient evidences are found to support valproic acid in the treatment of dementia for cognitive, psychiatric symptoms or disease-modifying. The anticipations for a success in the trial of valproic acid for dementia in the future look not optimistic based on the available evidence.

Modifiable risk and protective factors in disease development, progression and clinical subtypes of Parkinson's disease: What do prospective studies suggest?

Parkinson's disease (PD) is a neurodegenerative disorder whose pathogenesis depends on a combination of genetic and environmental factors. The aim of the present review was to provide an updated description of the findings emerging from prospective longitudinal cohort studies on the possible risk/protective factors underlying the development, progression and clinical subtypes of PD. We reviewed all the environmental, lifestyle, dietary, comorbid and pharmacological factors that have been investigated as possible modifiable protective/risk factors for PD by longitudinal studies. Only a few factors have the epidemiological evidence and the biological plausibility to be considered risk (pesticides, dairy products, β2-adrenoreceptor antagonists) or protective (smoking, caffeine and tea intake, physical activity, gout, vitamin E intake, non-steroidal anti-inflammatory drugs and β2-adrenoreceptor agonists) factors for PD. Caffeine intake and physical activity also seem to slow down the progression of the disease, thus representing good candidates for primary prevention and disease modifying strategies in PD. Possible modifiable risk factors of PD subtypes is almost unknown and this might depend on the uncertain biological and neuropathological reliability of clinical subtypes. The results of the present review suggest that only eleven risk/protective factors may be associated with the risk of PD. It may be possible to target some of these factors for preventive interventions aimed at reducing the risk of developing and the rate of progression of PD.

CoQ10 and Aging

The aging process includes impairment in mitochondrial function, a reduction in anti-oxidant activity, and an increase in oxidative stress, marked by an increase in reactive oxygen species (ROS) production. Oxidative damage to macromolecules including DNA and electron transport proteins likely increases ROS production resulting in further damage. This oxidative theory of cell aging is supported by the fact that diseases associated with the aging process are marked by increased oxidative stress. Coenzyme Q10 (CoQ₁₀) levels fall with aging in the human but this is not seen in all species or all tissues. It is unknown whether lower CoQ₁₀ levels have a part to play in aging and disease or whether it is an inconsequential cellular response to aging. Despite the current lay public interest in supplementing with CoQ₁₀, there is currently not enough evidence to recommend CoQ₁₀ supplementation as an anti-aging anti-oxidant therapy.

Mitochondrial Dysfunction in Neural Injury

Mitochondria are the double membrane organelles providing most of the energy for cells. In addition, mitochondria also play essential roles in various cellular biological processes such as calcium signaling, apoptosis, ROS generation, cell growth, and cell cycle. Mitochondrial dysfunction is observed in various neurological disorders which harbor acute and chronic neural injury such as neurodegenerative diseases and ischemia, hypoxia-induced brain injury. In this review, we describe how mitochondrial dysfunction contributes to the pathogenesis of neurological disorders which manifest chronic or acute neural injury.

The efficacy and safety of riluzole for neurodegenerative movement disorders: a systematic review with meta-analysis

Neurodegenerative movement disorders mainly include Parkinson’s disease, atypical parkinsonisms, Huntington disease, and hereditary ataxia. Riluzole is the only drug approved by the US Food and Drug Administration for amyotrophic lateral sclerosis. The neuroprotective effects of riluzole have been observed in experimental models of neurodegenerative movement disorders. In this paper, we aimed to systematically analyze the efficacy and safety of riluzole for patients with neurodegenerative movement disorder. We searched the electronic databases such as PubMed, EMBASE, CINAHL, Cochrane Library and China National Knowledge Infrastructure until June 2017 for the eligible randomized controlled trials, as well as the unpublished and ongoing trials. For continuous data, we calculated standardized mean differences with 95% confidence intervals if studies did not use the same scales to measure outcomes. For dichotomous data, we calculated risk differences if a trial reported no adverse events or dropouts. We pooled the results using a random-effects model. We included nine studies with 1320 patients with neurodegenerative movement disorders, which compared riluzole with placebo. No significant difference was found in the number of participants with adverse events but with motor improvement in hereditary ataxia. There were only two studies focusing on neuroprotective effect. Riluzole is well-tolerated in the patients with neurodegenerative movement disorders. Riluzole seems to be promising for patients with hereditary ataxia in symptomatic effect, which needs to be further confirmed by well-designed studies in the future. Moreover, it makes sense to design long-term study focusing on neuroprotective effect of riluzole in disease-modifying.

The Effect of MitoQ on Aging-Related Biomarkers: A Systematic Review and Meta-Analysis

Mitochondria are metabolically active organelles that produce significant reactive oxygen species, linked with aging and degenerative diseases. In recent years, particular focus has been put on mitochondria-targeted antioxidants, to decrease the concentration of reactive oxygen species and help alleviate the accumulation of oxidative damage and associated aging. MitoQ is a mitochondria-targeted antioxidant of which is reported to support healthy aging. The aim of this systematic review is to investigate the effects of MitoQ on oxidative outcomes related to the aging process. A predeveloped search strategy was run against MEDLINE (Ovid), EMBASE (Ovid), and CINAHL databases, which identified 10,255 articles of interest, with 27 of these finalised for use after screening. Three outcomes had sufficient data to meta-analyse nitrotyrosine concentration (190 animals, SMD -0.67, 95% CI (-1.30, -0.05), p = 0.04), membrane potential (63 animals, MD 11.44, 95% CI (1.28-21.60), p = 0.03), and protein carbonyl concentration (182 animals, SMD -0.13, 95% CI (-0.44, 0.18), p = 0.41). MitoQ intervention produced a statistically significant reduction in nitrotyrosine concentration and increased membrane potential. MitoQ may be of some benefit in alleviating oxidative stress related to aging.

Current perspective of mitochondrial biology in Parkinson's disease

Parkinson's disease (PD) is one of the most common neurodegenerative movement disorder characterized by preferential loss of dopaminergic neurons of the substantia nigra pars compacta and the presence of Lewy bodies containing α-synuclein. Although the cause of PD remains elusive, remarkable advances have been made in understanding the possible causative mechanisms of PD pathogenesis. An explosion of discoveries during the past two decades has led to the identification of several autosomal dominant and recessive genes that cause familial forms of PD. The investigations of these familial PD gene products have shed considerable insights into the molecular pathogenesis of the more common sporadic PD. A growing body of evidence suggests that the etiology of PD is multifactorial and involves a complex interplay between genetic and environmental factors. Substantial evidence from human tissues, genetic and toxin-induced animal and cellular models indicates that mitochondrial dysfunction plays a central role in the pathophysiology of PD. Deficits in mitochondrial functions due to bioenergetics defects, alterations in the mitochondrial DNA, generation of reactive oxygen species, aberrant calcium homeostasis, and anomalies in mitochondrial dynamics and quality control are implicated in the underlying mechanisms of neuronal cell death in PD. In this review, we discuss how familial PD-linked genes and environmental factors interface the pathways regulating mitochondrial functions and thereby potentially converge both familial and sporadic PD at the level of mitochondrial integrity. We also provide an overview of the status of therapeutic strategies targeting mitochondrial dysfunction in PD. Unraveling potential pathways that influence mitochondrial homeostasis in PD may hold the key to therapeutic intervention for this debilitating neurodegenerative movement disorder.

Coenzyme Q10 Supplementation in Aging and Disease

Coenzyme Q (CoQ) is an essential component of the mitochondrial electron transport chain and an antioxidant in plasma membranes and lipoproteins. It is endogenously produced in all cells by a highly regulated pathway that involves a mitochondrial multiprotein complex. Defects in either the structural and/or regulatory components of CoQ complex or in non-CoQ biosynthetic mitochondrial proteins can result in a decrease in CoQ concentration and/or an increase in oxidative stress. Besides CoQ₁₀ deficiency syndrome and aging, there are chronic diseases in which lower levels of CoQ₁₀ are detected in tissues and organs providing the hypothesis that CoQ₁₀ supplementation could alleviate aging symptoms and/or retard the onset of these diseases. Here, we review the current knowledge of CoQ₁₀ biosynthesis and primary CoQ₁₀ deficiency syndrome, and have collected published results from clinical trials based on CoQ₁₀ supplementation. There is evidence that supplementation positively affects mitochondrial deficiency syndrome and the symptoms of aging based mainly on improvements in bioenergetics. Cardiovascular disease and inflammation are alleviated by the antioxidant effect of CoQ₁₀. There is a need for further studies and clinical trials involving a greater number of participants undergoing longer treatments in order to assess the benefits of CoQ₁₀ treatment in metabolic syndrome and diabetes, neurodegenerative disorders, kidney diseases, and human fertility.

Mitochondrial dysfunction activates lysosomal-dependent mitophagy selectively in cancer cells

Molecules designed to target and accumulate in the mitochondria are an emerging therapeutic approach for cancer and other indications. Mitochondria-targeted redox agents (MTAs) induce mitochondrial damage and autophagy in cancer cells. However, the mechanisms for these molecules to induce mitophagy, the clearance of damaged mitochondria, are largely unknown. Using breast derived cell lines and a series of targeted molecules, mitochondrial dysfunction and autophagy was established to be selective for MDA-MB-231 cancer cells as compared to the non-cancerous MCF-12A cells. Kinetic analyses revealed that mitochondrial dysfunction precedes the activation of autophagy in these cancer cells. To determine the onset of mitophagy, stably expressing mitochondrial mKeima, a mitochondrial pH sensor, cell lines were generated and revealed that these drugs activate lysosomal dependent mitochondrial degradation in MDA-MB-231 cells. Mitophagy was confirmed by identifying the accumulation of a PINK1, mitochondria located in autophagosomes, and the formation of an autophagosome-mitochondria protein (MFN2-LC3-II) complex. These results are the first to demonstrate that mitochondrial redox agents selectively induce mitophagy in a breast cancer cell line and their potential application both as tools for investigating mitochondrial biomechanics and as therapeutic strategies that target mitochondrial metabolism.

Experimental and Clinical Strategies for Treating Spinocerebellar Ataxia Type 3

Spinocerebellar ataxia type 3 (SCA3), or Machado-Joseph disease (MJD), is an autosomal dominant neurodegenerative disorder caused by the expansion of a polyglutamine (polyQ) tract in the ataxin-3 protein. To date, there is no effective therapy available to prevent progression of this disease. However, clinical strategies for alleviating various symptoms are imperative to promote a better quality of life for SCA3/MJD patients. Furthermore, experimental therapeutic strategies, including gene silencing or mutant protein clearance, mutant polyQ protein modification, stabilizing the native protein conformation, rescue of cellular dysfunction and neuromodulation to slow the progression of SCA3/MJD, have been developed. In this study, based on the current knowledge, I detail the clinical and experimental therapeutic strategies for treating SCA3/MJD, paying particular attention to drug discovery.

Nutritional habits, risk, and progression of Parkinson disease

Parkinson disease (PD) is a multifactorial disease, where a genetic predisposition combines with putative environmental risk factors. Mounting evidence suggests that the initial PD pathological manifestations may be located in the gut to subsequently affect brain areas. Moreover, several lines of research demonstrated that there are bidirectional connections between the central nervous system and the gut, the "gut-brain axis" that influences both brain and gastrointestinal function. This opens a potential therapeutic window suggesting that specific dietary strategies may interact with the disease process and influence the risk of PD or modify its course. Dietary components can also theoretically modulate the chronic activation of the inflammatory response that is associated with aging, the strongest risk factor for PD, that has been suggested to hasten the underlying neurodegenerative process in PD. Here, we reviewed the evidence supporting an association between certain dietary compound and either the risk or progression of PD and have provided an overview of the possible pathomechanisms linking nutrition and neurodegeneration. The results of our review would not support a clear role for any dietary components in reducing the risk or progression of PD. However, the evidence favouring a connection between gut abnormalities, inflammation, and neurodegeneration in PD have become too compelling to be ignored, so that further research, also in the field of nutritional genomics, is highly warranted.

Novel targets for mitochondrial medicine

Mitochondria-classically viewed as the powerhouses of the cell-have taken center stage in disease pathogenesis and resolution. Mitochondrial dysfunction, which originates from primary defects within the organelle or is induced by environmental stresses, plays a critical role in human disease. Despite their central role in human health and disease, there are no approved drugs that directly target mitochondria. We present possible new druggable targets in mitochondrial biology, including protein modification, calcium ion (Ca(2+)) transport, and dynamics, as we move into a new era of mitochondrial medicine.

Efficient synthesis and antioxidant activities of N-heterocyclyl substituted Coenzyme Q analogues

A new strategy for the efficient synthesis of C-5 heterocyclyl substituted Coenzyme Q analogues was developed by N-alkylation of bromomethylated quinone 11 with a series of amines 12 under metal-free conditions. In vitro antioxidant activities of these Coenzyme Q analogues were evaluated and compared with commercial antioxidant Coenzyme Q10 by employing DPPH assay. All these N-heterocyclyl substituted Coenzyme Q analogues are found to be exhibiting good antioxidant properties and may be used as potent antioxidants for combating oxidative stress.

Allogeneic/xenogeneic transplantation of peptide-labeled mitochondria in Parkinson's disease: restoration of mitochondria functions and attenuation of 6-hydroxydopamine-induced neurotoxicity

Although restoration of mitochondrial function in mitochondrial diseases through peptide-mediated allogeneic mitochondrial delivery (PMD) has been demonstrated in vitro, the in vivo therapeutic efficacy of PMD in Parkinson's disease (PD) has yet to be determined. In this study, we compared the functionality of mitochondrial transfer with or without Pep-1 conjugation in neurotoxin (6-hydroxydopamine, 6-OHDA)-induced PC12 cells and PD rat models. We injected mitochondria into the medial forebrain bundle (MFB) of the PD rats after subjecting the nigrostriatal pathway to a unilateral 6-OHDA lesion for 21 days, and we verified the effectiveness of the mitochondrial graft in enhancing mitochondrial function in the soma of the substantia nigra (SN) neuron through mitochondrial transport dynamics in the nigrostriatal circuit. The result demonstrated that only PMD with allogeneic and xenogeneic sources significantly sustained mitochondrial function to resist the neurotoxin-induced oxidative stress and apoptotic death in the rat PC12 cells. The remaining cells exhibited a greater capability of neurite outgrowth. Furthermore, allogeneic and xenogeneic transplantation of peptide-labeled mitochondria after 3 months improved the locomotive activity in the PD rats. This increase was accompanied by a marked decrease in dopaminergic neuron loss in the substantia nigra pars compacta (SNc) and consistent enhancement of tyrosine hydroxylase-positive immunoreaction of dopaminergic neurons in the SNc and striatum. We also observed that in the SN dopaminergic neuron in the treated PD rats, mitochondrial complex I protein and mitochondrial dynamics were restored, thus ameliorating the oxidative DNA damage. Moreover, we determined signal translocation of graft allogeneic mitochondria from the MFB to the calbindin-positive SN neuron, which demonstrated the regulatory role of mitochondrial transport in alleviating 6-OHDA-induced degeneration of dopaminergic neurons.

Ophthalmic manifestations of inherited neurodegenerative disorders

Ophthalmic findings are common features of neurodegenerative disorders and, in addition to being clinically important, have emerged as potentially useful biomarkers of disease progression in several conditions. Clinically, these visual system abnormalities can be a clue to diagnosis, as well as being a prominent cause of disability in affected patients. In this Review, we describe the various afferent visual system and other ophthalmic features of inherited neurodegenerative disorders, including the muscular dystrophies, Friedreich ataxia, the spinocerebellar ataxias, hereditary spastic paraplegia, Charcot-Marie-Tooth disease, and other conditions. We focus on the expanding role of optical coherence tomography in diagnostic imaging of the retina and optic nerve head, and the possible use of ophthalmic findings as biomarkers of disease severity in hereditary neurodegenerative disorders. In addition, we discuss the ophthalmic manifestations and treatment implications of mitochondrial dysfunction, which is a feature of many inherited neurodegenerative diseases.