PURPOSE: Children with mitochondrial disease (MD) have clinical phenotypes that are more severe than those found in adults. In this study, we assessed cardiac function in children with MD using conventional and advanced echocardiographic measurements, explored any unique patterns present, and investigated the development of early cardiomyopathy (CMP). MATERIALS AND METHODS: We retrospectively reviewed the medical records of 33 children with MD. All patients underwent transthoracic echocardiography with conventional and advanced myocardial analysis. We compared all data between patients and an age-matched healthy control group. RESULTS: Conventional echocardiographic diastolic measurements of mitral E, E/A, and tissue Doppler E′ were significantly lower and E/E′ was significantly higher in children with MD, compared with the measurements from the control group. There was no significant difference in longitudinal and radial strain between the groups. Circumferential strain in the endocardium (p=0.161), middle myocardium (p=0.008), and epicardium (p=0.042) were lower in patients, compared to the values in controls. Circumferential strain was correlated with E′ (p < 0.01, r>0.60). CONCLUSION: In children with MD, myocardial circumferential strain may develop early in all three layers, even with normally preserved longitudinal and radial strain. This may be an early diagnostic indicator with which to predict CMP in this patient population.
Biomechanical Phenomena ; Child ; Echocardiography, Doppler ; Female ; Humans ; Male ; Mitochondrial Diseases/diagnostic imaging ; Mitochondrial Diseases/pathology ; Mitochondrial Diseases/physiopathology ; Myocardium/pathology

PURPOSE: The disease entity mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is characterized by an early onset of stroke-like episodes. MELAS is the most dominant subtype of mitochondrial disease. Molecular genetic testing is important in the diagnosis of MELAS. The mitochondrial DNA (mtDNA) 3243A>G mutation is found in 80% of MELAS patients. Nevertheless, molecular analysis alone may be insufficient to diagnose MELAS because of mtDNA heteroplasmy. This study aimed to evaluate whether muscle biopsy is useful in MELAS patients as an initial diagnostic evaluation method. MATERIALS AND METHODS: The medical records of patients who were diagnosed with MELAS at the Department of Pediatrics of Gangnam Severance Hospital between January 2006 and January 2017 were reviewed. The study population included 12 patients. They were divided into two subgroups according to whether the results of muscle pathology were in accordance with mitochondrial diseases. Clinical variables, diagnostic evaluations, and clinical outcomes were compared between the two groups. RESULTS: Of the 12 patients, seven were muscle pathology-positive for mitochondrial disease. No statistically significant difference in clinical data was observed between the groups that were muscle pathology-positive and muscle pathology-negative for mtDNA 3243A>G mutation. Additionally, the patients with weakness as the initial symptom were all muscle pathology-positive. CONCLUSION: The usefulness of muscle biopsy appears to be limited to an initial confirmative diagnostic evaluation of MELAS. Muscle biopsy can provide some information in MELAS patients with weakness not confirmed by genetic testing.
Biopsy* ; Diagnosis ; DNA, Mitochondrial ; Genetic Testing ; Humans ; Medical Records ; MELAS Syndrome* ; Methods ; Mitochondrial Diseases ; Mitochondrial Encephalomyopathies* ; Molecular Biology ; Pathology ; Pediatrics

Mitochondrial genome is responsible for multiple human diseases in a maternal inherited pattern, yet phenotypes of patients in a same pedigree frequently vary largely. Genes involving in epigenetic modification, RNA processing, and other biological pathways, rather than "threshold effect" and environmental factors, provide more specific explanation to the aberrant phenotype. Thus, the double hit theory, mutations both in mitochondrial DNA and modifying genes aggravating the symptom, throws new light on mitochondrial dysfunction processes. In addition, mitochondrial retrograde signaling pathway that leads to reconfiguration of cell metabolism to adapt defects in mitochondria may as well play an active role. Here we review selected examples of modifier genes and mitochondrial retrograde signaling in mitochondrial disorders, which refine our understanding and will guide the rational design of clinical therapies.
Animals ; Cell Nucleus ; genetics ; DNA, Mitochondrial ; genetics ; Humans ; Mitochondrial Diseases ; genetics ; pathology ; Mutation ; Signal Transduction

The great majority of genetic disorders are caused by defects in the nuclear genome. However, some significant diseases are the result of mitochondrial mutations. Because of the unique features of the mitochondria, these diseases display characteristic modes of inheritance and a large degree of phenotypic variability. Recent studies have suggested that mitochondrial dysfunction plays a central role in a wide range of age-related disorders and various forms of cancer.
DNA, Mitochondrial ; metabolism ; Genetic Diseases, Inborn ; diagnosis ; genetics ; Humans ; Mitochondria ; physiology ; Mitochondrial Diseases ; metabolism ; pathology ; Mutation ; Neoplasms ; diagnosis ; genetics ; pathology ; Oxidative Phosphorylation ; Oxygen ; Phenotype ; Reactive Oxygen Species

No abstract available.
Aged ; Female ; Humans ; Hypertension, Pulmonary/*etiology ; Mitochondrial Diseases/*complications/*pathology/physiopathology

Blepharoptosis is a common indication for surgery in plastic surgery units, yet its possible underlying pathology frequently remains unidentified. A 52-year-old man with a 20-year history of progressive bilateral ptosis (right>left) presented with recurrent ptosis of both eyes; he had undergone an operation on the levator aponeurosis 12 years prior. Due to the suspicion of an underlying disease, he was evaluated further. Chronic progressive external ophthalmoplegia in transition to the more severe syndromic variant Kearns-Sayre syndrome, a mitochondrial disorder causing myopathy, was diagnosed. The patient was treated with coenzyme Q10, and he underwent ptosis surgery on both eyes. This case illustrates a potentially multi-systemic disease that was diagnosed by a further evaluation of a common symptom, in this case worsening blepharoptosis. Awareness of myopathic symptoms is necessary to prevent overlooking serious yet improvable conditions.
Blepharoplasty ; Blepharoptosis* ; Humans ; Kearns-Sayre Syndrome* ; Middle Aged ; Mitochondrial Diseases ; Muscular Diseases ; Ophthalmoplegia, Chronic Progressive External ; Pathology ; Surgery, Plastic

A (99m)Tc-sestamibi scan has become the most widely used localizing test for identifying a parathyroid adenoma. Despite its popularity, the effectiveness of (99m)Tc-sestamibi scan for parathyroid localization is still controversial due to the large number of false-positive results. The false positive (99m)Tc-sestamibi scan can be attributed to a thyroid adenoma, nodular hyperplasia, metastatic thyroid cancer and other proliferating thyroid diseases because (99m)Tc-sestamibi is specific to the mitochondrial membrane of cells with high-level metabolic status, and not specific to the parathyroid itself. Minimally invasive radio-guided parathyroidectomy (MIRGP) was performed on a 61 year-old woman. The (99m)Tc-sestamibi focus was completely excised with gamma-probe guidance. However, the frozen pathology showed the excised tissue to be a thyroid papillary carcinoma. We present the unexpected false-positive (99m)Tc-sestamibi in MIRGP, and discuss the considerations in order to reduce the number of false-positive parathyroid (99m)Tc-sestamibi scans.
Carcinoma, Papillary ; Female ; Humans ; Hyperplasia ; Middle Aged ; Mitochondrial Membranes ; Parathyroid Neoplasms ; Parathyroidectomy* ; Pathology ; Thyroid Diseases ; Thyroid Gland ; Thyroid Neoplasms

Alzheimer Disease ; complications ; pathology ; therapy ; Amyloid beta-Peptides ; metabolism ; Humans ; Mitochondria ; physiology ; Mitochondrial Diseases ; etiology ; tau Proteins ; metabolism

Alzheimer's Disease (AD) is a progressive neurodegenerative disease, which is pathologically defined by the accumulation of amyloid plaques and hyper-phosphorylated tau aggregates in the brain. Mitochondrial dysfunction is also a prominent feature in AD, and the extracellular Aβ and phosphorylated tau result in the impaired mitochondrial dynamics. In this study, we generated an induced pluripotent stem cell (iPSC) line from an AD patient with amyloid precursor protein (APP) mutation (Val715Met; APP-V715M) for the first time. We demonstrated that both extracellular and intracellular levels of Aβ were dramatically increased in the APP-V715M iPSC-derived neurons. Furthermore, the APP-V715M iPSC-derived neurons exhibited high expression levels of phosphorylated tau (AT8), which was also detected in the soma and neurites by immunocytochemistry. We next investigated mitochondrial dynamics in the iPSC-derived neurons using Mito-tracker, which showed a significant decrease of anterograde and retrograde velocity in the APP-V715M iPSC-derived neurons. We also found that as the Aβ and tau pathology accumulates, fusion-related protein Mfn1 was decreased, whereas fission-related protein DRP1 was increased in the APP-V715M iPSC-derived neurons, compared with the control group. Taken together, we established the first iPSC line derived from an AD patient carrying APP-V715M mutation and showed that this iPSC-derived neurons exhibited typical AD pathological features, including a distinct mitochondrial dysfunction.
Alzheimer Disease ; Amyloid ; Brain ; Carisoprodol ; Humans ; Immunohistochemistry ; Mitochondrial Dynamics ; Neurites ; Neurodegenerative Diseases ; Neurons ; Pathology ; Plaque, Amyloid ; Pluripotent Stem Cells

Mitochondria are important intracellular organelles that produce energy for cellular development, differentiation, and growth. Mitochondrial DNA (mtDNA) presents a 10- to 20-fold higher susceptibility to genetic mutations owing to the lack of introns and histone proteins. The mtDNA repair system is relatively inefficient, rendering it vulnerable to reactive oxygen species (ROS) produced during ATP synthesis within the mitochondria, which can then target the mtDNA. Under conditions of chronic inflammation and excess stress, increased ROS production can overwhelm the antioxidant system, resulting in mtDNA damage. This paper reviews recent literature describing the pathophysiological implications of oxidative stress, mitochondrial dysfunction, and mitochondrial genome aberrations in aging hematopoietic stem cells, bone marrow failure syndromes, hematological malignancies, solid organ cancers, chronic inflammatory diseases, and other diseases caused by exposure to environmental hazards.
DNA, Mitochondrial/*genetics/metabolism ; Hematologic Diseases/genetics/*pathology ; Humans ; *Inflammation ; Mitochondria/genetics ; Mutation ; Neoplasms/genetics/*pathology ; Oxidative Stress ; Reactive Oxygen Species/metabolism