Emir Tas

Early thalamic lesions in patients with sleep-potentiated epileptiform activity

Objective: To compare the prevalence and type of early developmental lesions in patients with a clinical presentation consistent with electrical status epilepticus in sleep either with or without prominent sleep-potentiated epileptiform activity (PSPEA). Methods: We performed a case-control study and enrolled patients with 1) clinical features consistent with electrical status epilepticus in sleep, 2) ≥1 brain MRI scan, and 3) ≥1 overnight EEG recording. We quantified epileptiform activity using spike percentage, the percentage of 1-second bins in the EEG tracing containing at least 1 spike. PSPEA was present when spike percentage during non-REM sleep was ≥50% than spike percentage during wakefulness. Results: One hundred patients with PSPEA (cases) and 47 patients without PSPEA (controls) met the inclusion criteria during a 14-year period. Both groups were comparable in terms of clinical and epidemiologic features. Early developmental lesions were more frequent in cases (48% vs 19.2%, p = 0.002). Thalamic lesions were more frequent in cases (14% vs 2.1%, p = 0.037). The main types of early developmental lesions found in cases were vascular lesions (14%), periventricular leukomalacia (9%), and malformation of cortical development (5%). Vascular lesions were the only type of early developmental lesions that were more frequent in cases (14% vs 0%, p = 0.005). Conclusions: Patients with PSPEA have a higher frequency of early developmental lesions and thalamic lesions than a comparable population of patients without PSPEA. Vascular lesions were the type of early developmental lesions most related to PSPEA.

Humanin and Age-Related Diseases: A New Link?

Humanin (HN) is 24-amino acid mitochondria-associated peptide. Since its initial discovery over a decade ago, a role for HN has been reported in many biological processes such as apoptosis, cell survival, substrate metabolism, inflammatory response, and response to stressors such as oxidative stress, ischemia, and starvation. HN and its potent analogs have been shown to have beneficial effects in many age-related diseases including Alzheimer’s disease, stroke, diabetes, myocardial ischemia and reperfusion, atherosclerosis, amyotrophic lateral sclerosis, and certain types of cancer both in vitro and in vivo. More recently, an association between HN levels, growth hormone/insulin-like growth factor-1 (GH/IGF axis), and life span was demonstrated using various mouse models with mutations in the GH/IGF axis. The goal of this review is to summarize the current understanding of the role of HN in aging and age-related diseases.

Hepatic lipid metabolism and non-alcoholic fatty liver disease in aging

Aging is associated with dysregulation of glucose and lipid metabolism. Various factors that contribute to the dysregulation include both modifiable (e.g. obesity, insulin resistance) and non-modifiable risk factors (age-associated physiologic changes). Although there is no linear relationship between aging and prevalence of non-alcoholic fatty liver disease, current data strongly suggests that advanced age leads to more severe histological changes and poorer clinical outcomes. Hepatic lipid accumulation could lead to significant hepatic and systemic consequences including steatohepatitis, cirrhosis, impairment of systemic glucose metabolism and metabolic syndrome, thereby contributing to age-related diseases. Insulin, leptin and adiponectin are key regulators of the various physiologic processes that regulate hepatic lipid metabolism. Recent advances have expanded our understanding in this field, highlighting the role of novel mediators such as FGF 21, and mitochondria derived peptides. In this review, we will summarize the mediators of hepatic lipid metabolism and how they are altered in aging.

Central effects of Humanin on hepatic triglyceride secretion

Humanin (HN) is an endogenous mitochondria-associated peptide that has been shown to protect against various Alzheimers disease-associated insults, myocardial ischemia-reperfusion injury, and reactive oxygen species-induced cell death. We have shown previously that HN improves whole body glucose homeostasis by improving insulin sensitivity and increasing glucose-stimulated insulin secretion (GSIS) from the β-cells. Here, we report that intraperitoneal treatment with one of HN analogs, HNG, decreases body weight gain, visceral fat, and hepatic triglyceride (TG) accumulation in high-fat diet-fed mice. The decrease in hepatic TG accumulation is due to increased activity of hepatic microsomal triglyceride transfer protein (MTTP) and increased hepatic TG secretion. Both intravenous (iv) and intracerebroventricular (icv) infusion of HNG acutely increase TG secretion from the liver. Vagotomy blocks the effect on both iv and icv HNG on TG secretion, suggesting that the effects of HNG on hepatic TG flux are centrally mediated. Our data suggest that HN is a new player in central regulation of peripheral lipid metabolism.

Septo‐Optic Dysplasia Complicated by Infantile Spasms and Bilateral Choroidal Fissure Arachnoid Cysts

Septo‐optic dysplasia (SOD) is the triad of optic nerve hypoplasia, panhypopituitarism, and agenesis of septum pellucidum, and has been described previously to be associated with heterotopias and midline interhemispheric cyst. We describe a case of SOD with arachnoid cysts, persistent primary hyperplastic vitreous, and malformations of cortical development.

Humanin is an endogenous activator of chaperone-mediated autophagy

Chaperone-mediated autophagy (CMA) serves as quality control during stress conditions through selective degradation of cytosolic proteins in lysosomes. Humanin (HN) is a mitochondria-associated peptide that offers cytoprotective, cardioprotective, and neuroprotective effects in vivo and in vitro. In this study, we demonstrate that HN directly activates CMA by increasing substrate binding and translocation into lysosomes. The potent HN analogue HNG protects from stressor-induced cell death in fibroblasts, cardiomyoblasts, neuronal cells, and primary cardiomyocytes. The protective effects are lost in CMA-deficient cells, suggesting that they are mediated through the activation of CMA. We identified that a fraction of endogenous HN is present at the cytosolic side of the lysosomal membrane, where it interacts with heat shock protein 90 (HSP90) and stabilizes binding of this chaperone to CMA substrates as they bind to the membrane. Inhibition of HSP90 blocks the effect of HNG on substrate translocation and abolishes the cytoprotective effects. Our study provides a novel mechanism by which HN exerts its cardioprotective and neuroprotective effects.

Investigating the link of ACAD10 deficiency to type 2 diabetes mellitus

The Native American Pima population has the highest incidence of insulin resistance (IR) and type 2 diabetes mellitus (T2DM) of any reported population, but the pathophysiologic mechanism is unknown. Genetic studies in Pima Indians have linked acyl-CoA dehydrogenase 10 (ACAD10) gene polymorphisms, among others, to this predisposition. The gene codes for a protein with a C-terminus region that is structurally similar to members of a family of flavoenzymes—the acyl-CoA dehydrogenases (ACADs)—that catalyze α,β-dehydrogenation reactions, including the first step in mitochondrial FAO (FAO), and intermediary reactions in amino acids catabolism. Dysregulation of FAO and an increase in plasma acylcarnitines are recognized as important in the pathophysiology of IR and T2DM. To investigate the deficiency of ACAD10 as a monogenic risk factor for T2DM in human, an Acad-deficient mouse was generated and characterized. The deficient mice exhibit an abnormal glucose tolerance test and elevated insulin levels. Blood acylcarnitine analysis shows an increase in long-chain species in the older mice. Nonspecific variable pattern of elevated short-terminal branch-chain acylcarnitines in a variety of tissues was also observed. Acad10 mice accumulate excess abdominal adipose tissue, develop an early inflammatory liver process, exhibit fasting rhabdomyolysis, and have abnormal skeletal muscle mitochondria. Our results identify Acad10 as a genetic determinant of T2DM in mice and provide a model to further investigate genetic determinants for insulin resistance in humans.

Familial deletion of the HOXA gene cluster associated with Hand–Foot–Genital syndrome and phenotypic variability

Hand–Foot–Genital syndrome is a rare autosomal dominant condition characterized by distal limb anomalies and urogenital malformations. This disorder is associated with loss‐of‐function mutations in the HOXA13 gene. HOXA13 plays an important role in the development of distal limbs and lower genitourinary tract of the fetus. We report a novel familial 589 kb deletion in the 7p15.2 region identified in a male toddler and his mother. The proband had severe penoscrotal hypospadias, mild skeletal anomalies of the hands and feet, cardiac, renal, and gastrointestinal anomalies. His mother had a bicornuate uterus, cervical incompetence, and minor anomalies of her hands and feet. This family was found to have the smallest reported deletion of 7p15.2 to date, and presented with features typical of Hand–Foot–Genital syndrome in the mother, but much more severe phenotype in her son. This deletion included the entire HOXA cluster in addition to the SKAP2 and EVX1 genes. An RT‐PCR analysis was performed to determine the expression of the HOXA genes in the proband and to explore a parent‐of‐origin effect. Our expression studies did not support the hypothesis of an imprinted status of the HOXA2, HOXA3, HOXA5, and HOXA11 genes in peripheral blood. To our knowledge, this is the first familial 7p15.2 deletion. This family raises possibility for sexual dimorphism as a mechanism for phenotypic variability in patients with the HOXA gene cluster deletions.

Pericarditis as the Presenting Feature of Graves Disease in a Pediatric Patient.

Abstract Pericarditis is a rare presentation of thyrotoxicosis associated with Graves disease. This association has not been previously described in the pediatric literature. We report a 17-year-old male patient who presented with chest pain, dyspnea, and tachycardia. He was found to have diffuse ST-segment elevation consistent with pericarditis. At presentation, he was noted to have bilateral proptosis. Abnormal thyroid function studies and an elevated thyroid-stimulating hormone receptor antibody level confirmed the diagnosis of Graves thyrotoxicosis. The patient was treated with anti-inflammatory and antithyroid agents and improved in time. We discuss previously reported cases of Graves disease–associated pericarditis in adults, potential etiologies, and management strategies.