Advances in primary mitochondrial myopathies.

PURPOSE OF REVIEW: Although mitochondrial diseases impose a significant functional limitation in the lives of patients, treatment of these conditions has been limited to dietary supplements, exercise, and physical therapy. In the past few years, however, translational medicine has identified potential therapies for these patients. RECENT FINDINGS: For patients with primary mitochondrial myopathies, preliminary phase I and II multicenter clinical trials of elamipretide indicate safety and suggest improvement in 6-min walk test (6MWT) performance and fatigue scales. In addition, for thymidine kinase 2-deficient (TK2d) myopathy, compassionate-use oral administration of pyrimidine deoxynucleosides have shown preliminary evidence of safety and efficacy in survival of early onset patients and motor functions relative to historical TK2d controls. SUMMARY: The prospects of effective therapies that improve the quality of life for patients with mitochondrial myopathy underscore the necessity for definitive diagnoses natural history studies for better understanding of the diseases.

CoQ10 supplementation rescues nephrotic syndrome through normalization of H2S oxidation pathway.

Nephrotic syndrome (NS), a frequent chronic kidney disease in children and young adults, is the most common phenotype associated with primary coenzyme Q10 (CoQ10) deficiency and is very responsive to CoQ10 supplementation, although the pathomechanism is not clear. Here, using a mouse model of CoQ deficiency-associated NS, we show that long-term oral CoQ10 supplementation prevents kidney failure by rescuing defects of sulfides oxidation and ameliorating oxidative stress, despite only incomplete normalization of kidney CoQ levels and lack of rescue of CoQ-dependent respiratory enzymes activities. Liver and kidney lipidomics, and urine metabolomics analyses, did not show CoQ metabolites. To further demonstrate that sulfides metabolism defects cause oxidative stress in CoQ deficiency, we show that silencing of sulfide quinone oxido-reductase (SQOR) in wild-type HeLa cells leads to similar increases of reactive oxygen species (ROS) observed in HeLa cells depleted of the CoQ biosynthesis regulatory protein COQ8A. While CoQ10 supplementation of COQ8A depleted cells decreases ROS and increases SQOR protein levels, knock-down of SQOR prevents CoQ10 antioxidant effects. We conclude that kidney failure in CoQ deficiency-associated NS is caused by oxidative stress mediated by impaired sulfides oxidation and propose that CoQ supplementation does not significantly increase the kidney pool of CoQ bound to the respiratory supercomplexes, but rather enhances the free pool of CoQ, which stabilizes SQOR protein levels rescuing oxidative stress.

Emerging therapies for mitochondrial diseases.

For the vast majority of patients with mitochondrial diseases, only supportive and symptomatic therapies are available. However, in the last decade, due to extraordinary advances in defining the causes and pathomechanisms of these diverse disorders, new therapies are being developed in the laboratory and are entering human clinical trials. In this review, we highlight the current use of dietary supplement and exercise therapies as well as emerging therapies that may be broadly applicable across multiple mitochondrial diseases or tailored for specific disorders. Examples of non-tailored therapeutic targets include: activation of mitochondrial biogenesis, regulation of mitophagy and mitochondrial dynamics, bypass of biochemical defects, mitochondrial replacement therapy, and hypoxia. In contrast, tailored therapies are: scavenging of toxic compounds, deoxynucleoside and deoxynucleotide treatments, cell replacement therapies, gene therapy, shifting mitochondrial DNA mutation heteroplasmy, and stabilization of mutant mitochondrial transfer RNAs.

Homotoxicological remedies versus desmopressin versus placebo in the treatment of enuresis: a randomised, double-blind, controlled trial.

The aim of this trial was to compare the safety and efficacy of homotoxicological remedies versus placebo and versus desmopressin (dDAVP) in the treatment of monosymptomatic nocturnal enuresis (MNE). We conducted a randomised, double-blind, double-dummy, controlled trial in which 151 children with MNE were randomly assigned to receive oral homotoxicological remedies (n = 50), dDAVP (n = 50) or placebo (n = 51). The primary outcomes were: the reduction of wet nights per week after 3 months of therapy; the evaluation of the numbers and percentages of non-responders and responders; the number of children relapsing after initial response and the number of children attaining 14 consecutive dry nights during the treatment. The secondary outcome was the detection of adverse effects. Baseline clinical characteristics were similar in the three groups of patients. After the 3 months of therapy there was a significant difference between the three groups (P < 0.001) in the mean number of wet nights per week. The daily dose of dDAVP produced a statistically significant decrease (62.9%) in wet nights compared to placebo (2.4%) (P < 0.001) and compared to homotoxicological remedies (30.0%) (P < 0.001). There was a significant decrease in wet nights among the group treated with homotoxicological medications if compared with placebo (P < 0.001). The full response achieved with homotoxicological remedies (20%) was superior if compared with placebo (0%) (P < 0.001). Homotoxicology was superior to placebo (P < 0.001) with regard to the number of children attaining 14 consecutive dry nights during treatment. Our study demonstrates that homotoxicology is safe and effective when compared with placebo, even if it is significantly less effective than dDAVP in this clinical condition.