Mitochondrial glutamyl-aminoacyl tRNA synthetase deficiency, stemming from biallelic mutations in the EARS2 gene, was first described in 2012. With <50 cases reported globally, this condition exhibits a distinct phenotype of neonatal or childhood-onset, often referred to as leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL). It has also been one of the few reversible mitochondrial disorders described. The natural history of these patients is poorly documented, ranging from clinical and radiological improvement to early death. Herein, we detail three cases from our centre, including follow-up on the Portuguese patient reported by Steenweg et al., These cases illustrate the phenotypic spectrum: i) rapidly progressive neonatal presentation with lactic acidemia and corpus callosum agenesis, leading to early death; ii) early onset with a severe, slowly progressive course; iii) early onset with a milder phenotype, showing some improvement and mild neurological symptoms. Additionally, we conducted a systematic literature review on cases of EARS2-deficient patients, focusing on clinical manifestations, laboratory findings, radiological aspects, and disease progression over time, along with respective data analysis. \"Patients with EARS2 deficiency typically present within the first year of life with a well-defined neurometabolic disorder picture, often including hypotonia and/or spasticity, along with neurodevelopmental delay or regression. There are no pathognomonic features specific to EARS2 deficiency, and no genotype-phenotype correlation has been identified.\" Comparing to initial characterization by Steenweg et al., this analysis reveals an expanded disease spectrum. We propose a novel strategy for clustering phenotypes into severe, moderate, or mild disease based on initial presentation, seemingly correlating with disease progression. The paucity of data on the disease\'s natural history highlights the need for a multicentric approach to enhance understanding and management. TAKE-HOME MESSAGE: Analysis of all cases published with EARS2 deficiency allows for establish disease spectrum and a novel strategy for clustering phenotypes which correlate to disease progression.

COQ8A plays an important role in the biosynthesis of coenzyme Q10 (CoQ10), and variations in COQ8A gene are associated with primary CoQ10 deficiency-4 (COQ10D4), also known as COQ8A-ataxia. The current understanding of the association between the specific variant type, the severity of CoQ10 deficiency, and the degree of oxidative stress in individuals with primary CoQ10 deficiencies remains uncertain. Here we provide a comprehensive analysis of the clinical and genetic characteristics of an 18-year-old patient with COQ8A-ataxia, who exhibited novel compound heterozygous variants (c.1904_1906del and c.637C > T) in the COQ8A gene. These variants reduced the expression levels of COQ8A and mitochondrial proteins in the patient\'s muscle and skin fibroblast samples, contributed to mitochondrial respiration deficiency, increased ROS production and altered mitochondrial membrane potential. It is worth noting that the optimal treatment for COQ8A-ataxia remains uncertain. Presently, therapy consists of CoQ10 supplementation, however, it did not yield significant improvement in our patient\'s symptoms. Additionally, we reviewed the response of CoQ10 supplementation and evolution of patients in previous literatures in detail. We found that only half of patients could got notable improvement in ataxia. This research aims to expand the genotype-phenotype spectrum of COQ10D4, address discrepancies in previous reviews regarding the effectiveness of CoQ10 in these disorders, and help to establish a standardized treatment protocol for COQ8A-ataxia.

The increasing life expectancy observed in recent years has resulted in a higher prevalence of late-onset hypogonadism (LOH) in older men. LOH is characterized by the decline in testosterone levels and can have significant impacts on physical and mental health. While the underlying causes of LOH are not fully understood, there is a growing interest in exploring the role of inflammaging in its development. Inflammaging is a concept that describes the chronic, low-grade, systemic inflammation that occurs as a result of aging. This inflammatory state has been implicated in the development of various age-related diseases. Several cellular and molecular mechanisms have been identified as contributors to inflammaging, including immune senescence, cellular senescence, autophagy defects, and mitochondrial dysfunction. Despite the extensive research on inflammaging, its relationship with LOH has not yet been thoroughly reviewed in the literature. To address this gap, we aim to review the latest findings related to inflammaging and its impact on the development of LOH. Additionally, we will explore interventions that target inflammaging as potential treatments for LOH.

Aging is associated with decreased nicotinamide adenine dinucleotide (NAD) levels, which in turn cause dysfunctional mitochondria and indirectly affect a myriad of diseases. Intracellular nicotinamide phosphoribosyltransferase (iNAMPT) serves as a central rate-limiting enzyme in NAD synthesis, making it an indispensable health mediator. This meta-analysis examined the effect of exercise training on the expression of iNAMPT in humans.
We searched PubMed, Scopus, ClinicalTrials.gov, and the International Clinical Trials Registry Platform for studies published between the inception of the database and July 5, 2023. Using the common-effect model, evidence for the change in iNAMPT following exercise training was synthesized as Cohen\'s d.
The search yielded five eligible studies. The overall effect size is 0.81, with a 95% confidence interval of 0.55 to 1.07. Therefore, a random adult will have a 71.7% probability that iNAMPT will be up-regulated following exercise training. In general, exercise training resulted in a 1.46-fold increase in iNAMPT. Our probability statistics indicate that subgroups of interest may differ practically. Specifically, there is a 79.3% probability of increased iNAMPT in men, compared to a 69.0% probability in the overall population; young adults have a 75.6% probability of having an increased iNAMPT, whereas aged adults have a 68.7% probability; and, iNAMPT has a 75.1% probability increase after aerobic exercise and a 66.4% probability increase after resistance exercise.
Exercise training is effective for increasing iNAMPT levels in skeletal muscles. This essential enzyme regulates not only cellular energetics but also healthspan. Therefore, exercise should be promoted as a natural slow-aging lifestyle.

BACKGROUND: Leber hereditary optic neuropathy is a genetic disease of mitochondrial inheritance characterized by bilateral irreversible vision loss, predominantly affecting males. We report the first genetically authenticated Sri Lankan case of Leber hereditary optic neuropathy, illustrating its characteristic features of male predominance and variable penetrance.
METHODS: A 15-year-old previously healthy Sri Lankan boy presented with painless progressive vision loss in his right eye, followed by vision loss in his left eye within 3 months. There was no history of drug or toxin exposure, or a family history of vision loss. His parents were nonconsanguineous. On examination, he could only perceive light. Funduscopy revealed bilateral optic atrophy. Routine hematological and biochemical blood tests, including inflammatory markers, were normal. Cranial magnetic resonance imaging was unremarkable. Optical coherence tomography, and the clinical presentation, suggested a diagnosis of Leber hereditary optic neuropathy, which was confirmed by detection of m.14484T > C pathogenic variant in the MT-ND6 gene through targeted genetic analysis for the three common pathogenic variants in mitochondrial deoxyribonucleic acid. He was homoplasmic for the variant, and his asymptomatic mother and two female siblings were also found to be harboring the variant with homoplasmy.
CONCLUSIONS: This case report is intended to increase awareness of Leber hereditary optic neuropathy, and highlights the need to consider this rare diagnosis in the appropriate clinical context. It also illustrates the phenomena of incomplete penetrance and male predominance, and suggests the possibility of an X-linked gene governing Leber hereditary optic neuropathy disease expression, which warrants further investigation.

(1) Background: In this paper, we report on three cases of hypoacusis as part of a complex phenotype and some rare gene variants. An extensive review of literature completes the newly reported clinical and genetic information. (2) Methods: The cases range from 2- to 11-year-old boys, all with a complex clinical picture and hearing impairment. In all cases, whole exome sequencing (WES) was performed, in the first case in association with mitochondrial DNA study. (3) Results: The detected variants were: two heterozygous variants in the TWNK gene, one likely pathogenic and another of uncertain clinical significance (autosomal recessive mitochondrial DNA depletion syndrome type 7-hepatocerebral type); heterozygous variants of uncertain significance PACS2 and SYT2 genes (autosomal dominant early infantile epileptic encephalopathy) and a homozygous variant of uncertain significance in SUCLG1 gene (mitochondrial DNA depletion syndrome 9). Some of these genes have never been previously reported as associated with hearing problems. (4) Conclusions: Our cases bring new insights into some rare genetic syndromes. Although the role of TWNK gene in hearing impairment is clear and accordingly reflected in published literature as well as in the present article, for the presented gene variants, a correlation to hearing problems could not yet be established and requires more scientific data. We consider that further studies are necessary for a better understanding of the role of these variants.

Galectin‑3 is expressed in various tissues and plays an important role in the tumor microenvironment (TME). Galectin‑3 has been found to be overexpressed in a variety of cancers and is associated with tumor progression and metastasis. Over the past decades, emerging evidence has suggested that the TME may induce galectin‑3 expression to maintain cellular homeostasis and promote cell survival. Furthermore, galectin‑3 regulates immune cell function to promote tumor‑driven immunosuppression through several mechanisms. In the TME, intracellular and extracellular galectin‑3 has different functions. In addition, it has been reported that galectin‑3 is associated with glycolysis and mitochondrial metabolism in tumors, and it is involved in the regulation of relevant signaling pathways, thus promoting cancer cell survival via adapting to the TME. The aim of the present review was to summarize the current knowledge on galectin‑3 production and its function in the TME, its effect on TME immunosuppression, its association with tumor metabolism and relevant signaling pathways, and to report common types of cancer in which galectin‑3 is highly expressed, in order to ensure a comprehensive understanding of the critical effects of galectin‑3 on tumor progression and metastasis.

Biallelic pathogenic variants in mitochondrial aminoacyl-tRNA synthetase (mt-aaRS) PARS2 are associated with mitochondrial cytopathy. Here, we report the tenth case of an individual with biallelic PARS2 pathogenic variants, detected by exome sequencing (ES), and a literature review of ten cases of PARS2 mutations. Our patient displayed symptoms and clinical and laboratory findings similar to those reported previously with normal lactate levels. These symptoms included seizure disorder (which was managed with antiepileptics), developmental delay, and progressive cardiomyopathy which manifested at 19 years of age. The patient received a vitamin regimen including antioxidants as part of his treatment regimen. While further studies are required to conclusively establish the beneficial role of vitamin and cofactor administration on the mitochondria in PARS2-associated mitochondrial disease, these factors may have delayed the onset of cardiomyopathy.

The aim of this review is to summarize and discuss recent findings and new insights in the etiology and phenotype of metabolic myopathies. The review relies on a systematic literature review of recent publications. Metabolic myopathies are a heterogeneous group of disorders characterized by mostly inherited defects of enzymatic pathways involved in muscle cell metabolism. Metabolic myopathies present with either permanent (fixed) or episodic abnormalities, such as weakness, wasting, exercise-intolerance, myalgia, or an increase of muscle breakdown products (creatine-kinase, myoglobin) during exercise. Though limb and respiratory muscles are most frequently affected, facial, extra-ocular, and axial muscles may be occasionally also involved. Age at onset and prognosis vary considerably. There are multiple disease mechanisms and the pathophysiology is complex. Genes most recently related to metabolic myopathy include PGM1, GYG1, RBCK1, VMA21, MTO1, KARS, and ISCA2. The number of metabolic myopathies is steadily increasing. There is limited evidence from the literature that could guide diagnosis and treatment of metabolic myopathies. Treatment is limited to mainly non-invasive or invasive symptomatic measures. In conclusion, the field of metabolic myopathies is evolving with the more widespread availability and application of next generation sequencing technologies worldwide. This will broaden the knowledge about pathophysiology and putative therapeutic strategies for this group of neuromuscular disorders.

One of the systems that are potentially affected in mitochondrial disorders, but hardly get systematically investigated, are the arteries. One of the phenotypic manifestations in arteries is atherosclerosis. This review focuses on the current knowledge and recent advances of mitochondrial atherosclerosis. We conducted a systematic literature review via PubMed using appropriate search terms. Atherosclerosis in mitochondrial disorders may result from a primary pathomechanism or a secondary one due to mitochondrial diabetes, arterial hypertension, or hyperlipidemia. Anecdotal reports show that primary atherosclerosis can be a phenotypic feature of mitochondrial disorders. Predominantly, patients carrying mutations in mtDNA-located genes may develop primary mitochondrial atherosclerosis. Though not systematically investigated, it is conceivable that primary mitochondrial atherosclerosis results from increased oxidative stress, mitophagy, metabolic breakdown, or lactic acidosis. Mitochondrial disorder patients with primary mitochondrial atherosclerosis should receive not only antithrombotic medication but also antioxidants and cofactors. Atherosclerosis in mitochondrial disorders may occur even in the absence of classical atherosclerosis risk factors, suggesting that atherosclerosis can be a primary manifestation of the metabolic defect. Though primary atherosclerosis in mitochondrial disorders has not been systematically investigated, anecdotal data indicate that mitochondrial dysfunction can be a mechanism for the development of primary, mitochondrial atherosclerosis. These patients require antioxidants and cofactors in addition to antithrombotic medication.