Sex- and age-dependent susceptibility to ventricular arrhythmias in the rat heart ex vivo.

The incidence of life-threatening ventricular arrhythmias, the most common cause of sudden cardiac death (SCD), depends largely on the arrhythmic substrate that develops in the myocardium during the aging process. There is a large deficit of comparative studies on the development of this substrate in both sexes, with a particular paucity of studies in females. To identify the substrates of arrhythmia, fibrosis, cardiomyocyte hypertrophy, mitochondrial density, oxidative stress, antioxidant defense and intracellular Ca2+ signaling in isolated cardiomyocytes were measured in the hearts of 3- and 24-month-old female and male rats. Arrhythmia susceptibility was assessed in ex vivo perfused hearts after exposure to isoproterenol (ISO) and hydrogen peroxide (H2O2). The number of ventricular premature beats (PVBs), ventricular tachycardia (VT) and ventricular fibrillation (VF) episodes, as well as intrinsic heart rate, QRS and QT duration, were measured in ECG signals recorded from the surfaces of the beating hearts. After ISO administration, VT/VFs were formed only in the hearts of males, mainly older ones. In contrast, H2O2 led to VT/VF formation in the hearts of rats of both sexes but much more frequently in older males. We identified several components of the arrhythmia substrate that develop in the myocardium during the aging process, including high spontaneous ryanodine receptor activity in cardiomyocytes, fibrosis of varying severity in different layers of the myocardium (nonheterogenic fibrosis), and high levels of oxidative stress as measured by nitrated tyrosine levels. All of these elements appeared at a much greater intensity in male individuals during the aging process. On the other hand, in aging females, antioxidant defense at the level of H2O2 detoxification, measured as glutathione peroxidase expression, was weaker than that in males of the same age. We showed that sex has a significant effect on the development of an arrhythmic substrate during aging. This substrate determines the incidence of life-threatening ventricular arrhythmias in the presence of additional stimuli with proarrhythmic potential, such as catecholamine stimulation or oxidative stress, which are constant elements in the pathomechanism of most cardiovascular diseases.

Extracellular matrix molecules associated with lymphatic vessels in health and disease.

Lymphatic vessels (LyVs), responsible for fluid, solute, and immune cell homeostasis in the body, are closely associated with the adjacent extracellular matrix (ECM) molecules whose structural and functional impact on LyVs is currently more appreciated, albeit not entirely elucidated. These molecules, serving as a platform for various connective tissue cell activities and affecting LyV biology should be considered also as an integral part of the lymphatic system. Any alterations and changes in ECM molecules over the course of disease impair the function and structure of the LyV network. Remodeling of LyV cells, which are components of lymphatic vessel walls, also triggers alterations in ECM molecules and interstitial tissue composition. Therefore, in this review we aimed to present the current knowledge on ECM in tissues and particularly on molecules surrounding lymphatics in normal conditions and in disease.

Effect of age and sex on the incidence of ventricular arrhythmia in a rat model of acute ischemia.

BACKGROUND: The impact of sex and age on the arrhythmic susceptibility within the setting of acute ischemia is masked by the fact that acute coronary events result from coronary artery disease appearing with age much earlier among men than among women. METHODS AND RESULTS: LAD ligation or sham operations were performed in rats of both sexes at the age 3 and 24 months. An ECG was recorded continuously for 6 h after the operation. The number of early and late premature ventricular beats (PVBs), episodes of ventricular tachycardia (VT) and fibrillation (VF), heart rate, QRS, QT and Tpeak-Tend duration were analysed. Epicardial action potentials were recorded in vivo, Ca2+ signaling was evaluated in isolated cardiomyocytes, fibrosis and connexin-43 expression and localization were measured in the septum. PVBs, VT and VF episodes are much more common in older males than in young males and females independently from their age. Fibrosis with varying intensity in different muscle layers, hypertrophy of cardiomyocytes, reduced number of gap junctions and their appearance on the lateral myocyte membrane, QT prolongation, increase transmural dispersion of repolarisation and a decreased function of SERCA2a may increase the propensity to arrhythmia within the setting of acute ischemia. CONCLUSION: We show that the male sex, especially in case of older individuals is a strong predictor of increased arrhythmic susceptibility within the acute ischemia setting regardless of its impact on the occurrence of cardiovascular diseases. A personalized sex-dependent prevention treatment is needed to reduce the mortality in acute phases of myocardial infarction.

Congenital disorders of glycosylation in children - Histopathological and ultrastructural changes in the liver.

BACKGROUND: Congenital disorders of glycosylation (CDG) result from defects in the synthesis of glycans and their attachment to proteins and lipids. Histologically, liver steatosis, fibrosis and cirrhosis have been reported in CDG. The aim of the study was to characterize the histopathological and ultrastructural liver changes in CDG patients hospitalized in our Institute, and to find the most characteristic features, as articles concerning the liver microscopic features in CDG are sparse. METHODS: Out of 32 CDG patients diagnosed and followed-up in our Institute, the liver biopsy was performed in 4 of them, including 2 with MPI-CDG, 1 with SRD5A3-CDG, and 1 with PGM1-CDG, as a part of diagnostic process. In one patient, diagnosed post mortem with PMM2-CDG, the histopathological study comprised liver autopsy samples. RESULTS: The most common histopathological liver finding was the presence of steatosis (4/5) of varying severity, the mixed macro- and microvesicular type as well as the foamy degeneration of hepatocytes. In two patients, liver steatosis was associated with fibrosis, stage 4 (cirrhosis) and 2 according to Batts and Ludwig classification, respectively. In two patients, besides steatosis, mild inflammatory infiltrates composed of lymphoid cells in portal tracts were observed. No correlation between the patient's age and histopathological features was observed. CONCLUSIONS: The histopathological changes in the liver of CDG patients are miscellaneous; thus, based on the microscopic examination only, we can not identify (even suspect) the exact CDG. The most common histopathologic finding in our cohort of CDG patients was the presence of liver steatosis (of various severity) and foamy degeneration of hepatocytes.

Assessing functional status of cardiac lymphatics: From macroscopic imaging to molecular profiling.

Here we describe various techniques for visualization of the lymphatic vasculature, particularly in the heart. Addressing macro-, microscopic, and molecular levels of lymphatic organization, we give examples of how to explore the roles of specific antigens/markers expressed in lymphatic vessels and their extracellular matrix as structural and functional elements involved in various biological functions of lymphatics. Some obstacles and technical challenges related to lymphatic visualization are also discussed.

Microvascular and lymphatic dysfunction in HFpEF and its associated comorbidities.

Heart failure with preserved ejection fraction (HFpEF) is a complex heterogeneous disease for which our pathophysiological understanding is still limited and specific prevention and treatment strategies are lacking. HFpEF is characterised by diastolic dysfunction and cardiac remodelling (fibrosis, inflammation, and hypertrophy). Recently, microvascular dysfunction and chronic low-grade inflammation have been proposed to participate in HFpEF development. Furthermore, several recent studies demonstrated the occurrence of generalized lymphatic dysfunction in experimental models of risk factors for HFpEF, including obesity, hypercholesterolaemia, type 2 diabetes mellitus (T2DM), hypertension, and aging. Here, we review the evidence for a combined role of coronary (micro)vascular dysfunction and lymphatic vessel alterations in mediating key pathological steps in HFpEF, including reduced cardiac perfusion, chronic low-grade inflammation, and myocardial oedema, and their impact on cardiac metabolic alterations (oxygen and nutrient supply/demand imbalance), fibrosis, and cardiomyocyte stiffness. We focus primarily on HFpEF caused by metabolic risk factors, such as obesity, T2DM, hypertension, and aging.

Mutations in the V-ATPase Assembly Factor VMA21 Cause a Congenital Disorder of Glycosylation With Autophagic Liver Disease.

BACKGROUND AND AIMS: Vacuolar H+-ATP complex (V-ATPase) is a multisubunit protein complex required for acidification of intracellular compartments. At least five different factors are known to be essential for its assembly in the endoplasmic reticulum (ER). Genetic defects in four of these V-ATPase assembly factors show overlapping clinical features, including steatotic liver disease and mild hypercholesterolemia. An exception is the assembly factor vacuolar ATPase assembly integral membrane protein (VMA21), whose X-linked mutations lead to autophagic myopathy. APPROACH AND RESULTS: Here, we report pathogenic variants in VMA21 in male patients with abnormal protein glycosylation that result in mild cholestasis, chronic elevation of aminotransferases, elevation of (low-density lipoprotein) cholesterol and steatosis in hepatocytes. We also show that the VMA21 variants lead to V-ATPase misassembly and dysfunction. As a consequence, lysosomal acidification and degradation of phagocytosed materials are impaired, causing lipid droplet (LD) accumulation in autolysosomes. Moreover, VMA21 deficiency triggers ER stress and sequestration of unesterified cholesterol in lysosomes, thereby activating the sterol response element-binding protein-mediated cholesterol synthesis pathways. CONCLUSIONS: Together, our data suggest that impaired lipophagy, ER stress, and increased cholesterol synthesis lead to LD accumulation and hepatic steatosis. V-ATPase assembly defects are thus a form of hereditary liver disease with implications for the pathogenesis of nonalcoholic fatty liver disease.

Transcriptional and Ultrastructural Analyses Suggest Novel Insights into Epithelial Barrier Impairment in Celiac Disease.

Disruption of epithelial junctional complex (EJC), especially tight junctions (TJ), resulting in increased intestinal permeability, is supposed to activate the enhanced immune response to gluten and to induce the development of celiac disease (CD). This study is aimed to present the role of EJC in CD pathogenesis. To analyze differentially expressed genes the next-generation mRNA sequencing data from CD326+ epithelial cells isolated from non-celiac and celiac patients were involved. Ultrastructural studies with morphometry of EJC were done in potential CD, newly recognized active CD, and non-celiac controls. The transcriptional analysis suggested disturbances of epithelium and the most significant gene ontology enriched terms in epithelial cells from CD patients related to the plasma membrane, extracellular exome, extracellular region, and extracellular space. Ultrastructural analyses showed significantly tighter TJ, anomalies in desmosomes, dilatations of intercellular space, and shorter microvilli in potential and active CD compared to controls. Enterocytes of fetal-like type and significantly wider adherence junctions were observed only in active CD. In conclusion, the results do not support the hypothesis that an increased passage of gluten peptides by unsealing TJ precedes CD development. However, increased intestinal permeability due to abnormality of epithelium might play a role in CD onset.

LSEC Fenestrae Are Preserved Despite Pro-inflammatory Phenotype of Liver Sinusoidal Endothelial Cells in Mice on High Fat Diet.

Healthy liver sinusoidal endothelial cells (LSECs) maintain liver homeostasis, while LSEC dysfunction was suggested to coincide with defenestration. Here, we have revisited the relationship between LSEC pro-inflammatory response, defenestration, and impairment of LSEC bioenergetics in non-alcoholic fatty liver disease (NAFLD) in mice. We characterized inflammatory response, morphology as well as bioenergetics of LSECs in early and late phases of high fat diet (HFD)-induced NAFLD. LSEC phenotype was evaluated at early (2-8 week) and late (15-20 week) stages of NAFLD progression induced by HFD in male C57Bl/6 mice. NAFLD progression was monitored by insulin resistance, liver steatosis and obesity. LSEC phenotype was determined in isolated, primary LSECs by immunocytochemistry, mRNA gene expression (qRT-PCR), secreted prostanoids (LC/MS/MS) and bioenergetics (Seahorse FX Analyzer). LSEC morphology was examined using SEM and AFM techniques. Early phase of NAFLD, characterized by significant liver steatosis and prominent insulin resistance, was related with LSEC pro-inflammatory phenotype as evidenced by elevated ICAM-1, E-selectin and PECAM-1 expression. Transiently impaired mitochondrial phosphorylation in LSECs was compensated by increased glycolysis. Late stage of NAFLD was featured by prominent activation of pro-inflammatory LSEC phenotype (ICAM-1, E-selectin, PECAM-1 expression, increased COX-2, IL-6, and NOX-2 mRNA expression), activation of pro-inflammatory prostaglandins release (PGE2 and PGF2α) and preserved LSEC bioenergetics. Neither in the early nor in the late phase of NAFLD, were LSEC fenestrae compromised. In the early and late phases of NAFLD, despite metabolic and pro-inflammatory burden linked to HFD, LSEC fenestrae and bioenergetics are functionally preserved. These results suggest prominent adaptive capacity of LSECs that might mitigate NAFLD progression.

Three-dimensional nanofibrous polystyrene scaffolds modify macrophage phenotypes and activate macrophage angiogenic potential.

3D scaffolds represent an attractive substrate for studying macrophage activation and modification since they mimic extracellular matrix (ECM). However, macrophage response to such materials, particularly with respect to angiogenic potential is still poorly recognized. Therefore, we investigated the effect of 3D nanofibrous polystyrene scaffolds (NPSs) versus tissue culture polystyrene (TCPS) on THP-1-derived macrophages in various environmental conditions, for example, standard (m0), pro-inflammatory (m1), or anti-inflammatory (m2) with respect to pro-angiogenic potential. There were no differences in the expression of TNF-α and IL-10 mRNAs and respective proteins in cells cultured on NPSs compared with flat polystyrene (TCPS), however, NPSs induced an increased VEGF production by macrophages cultured in m0 and m1 media. Cells cultured in m1, and m2 conditions secreted elevated amounts of TNF-α and IL-10, respectively, irrespective of substrate surface geometry. Each macrophage population contains large, medium, and small cells. Moreover, there were significant differences in the proportion of large to small macrophages depending on the medium composition, that is, in m0, m1, and m2 media these proportions were 1:4, 1:3, and 1:10, respectively. The ultrastructure and the immunoexpression of TNF-α and IL-10 were analyzed under a confocal microscope. The results demonstrated differences in cell ultrastructure and suggested that the larger cells were pro-inflammatory macrophages, while the smaller cells were anti-inflammatory macrophages. In conclusion, NPSs activate macrophage pro-angiogenic potential. In addition, an increase in the proportion of pro-inflammatory macrophages relative to anti-inflammatory ones in a given population favors this potential.

Proepicardium: Current Understanding of its Structure, Induction, and Fate.

The proepicardium (PE) is a transitory extracardiac embryonic structure which plays a crucial role in cardiac morphogenesis and delivers various cell lineages to the developing heart. The PE arises from the lateral plate mesoderm (LPM) and is present in all vertebrate species. During development, mesothelial cells of the PE reach the naked myocardium either as free-floating aggregates in the form of vesicles or via a tissue bridge; subsequently, they attach to the myocardium and, finally, form the third layer of a mature heart-the epicardium. After undergoing epithelial-to-mesenchymal transition (EMT) some of the epicardial cells migrate into the myocardial wall and differentiate into fibroblasts, smooth muscle cells, and possibly other cell types. Despite many recent findings, the molecular pathways that control not only proepicardial induction and differentiation but also epicardial formation and epicardial cell fate are poorly understood. Knowledge about these events is essential because molecular mechanisms that occur during embryonic development have been shown to be reactivated in pathological conditions, for example, after myocardial infarction, during hypertensive heart disease or other cardiovascular diseases. Therefore, in this review we intended to summarize the current knowledge about PE formation and structure, as well as proepicardial cell fate in animals commonly used as models for studies on heart development. Anat Rec, 302:893-903, 2019. © 2018 Wiley Periodicals, Inc.

Structure and properties of composite surface layers produced on NiTi shape memory alloy by a hybrid method.

A hybrid process that combines oxidation under glow-discharge conditions with ion beam-assisted deposition (IBAD) has been applied to mechanically polished NiTi shape memory alloy in order to produce composite surface layers consisting of a TiO2 layer and an external carbon coating with an addition of silver. The produced surface layers a-C(Ag) + TiO2 type have shown increased surface roughness, improved corrosion resistance, altered wettability, and surface free energy, as well as reduced platelet adhesion, aggregation, and activation in comparison to NiTi alloy in initial state. Such characteristics can be of great benefit for cardiac applications.

Comparison of Pulmonary and Systemic NO- and PGI2-Dependent Endothelial Function in Diabetic Mice.

Diabetes increases the risk of pulmonary hypertension and is associated with alterations in pulmonary vascular function. Still, it is not clear whether alterations in the phenotype of pulmonary endothelium induced by diabetes are distinct, as compared to peripheral endothelium. In the present work, we characterized differences between diabetic complications in the lung and aorta in db/db mice with advanced diabetes. Male, 20-week-old db/db mice displayed increased HbA1c and glucose concentration compatible with advanced diabetes. Diabetic lungs had signs of mild fibrosis, and pulmonary endothelium displayed significantly ultrastructural changes. In the isolated, perfused lung from db/db mice, filtration coefficient (Kf,c) and contractile response to TXA2 analogue were enhanced, while endothelial NO-dependent modulation of pulmonary response to hypoxic ventilation and cumulative production of NO2- were impaired, with no changes in immunostaining for eNOS expression. In turn, 6-keto-PGF1α release from the isolated lung from db/db mice was increased, as well as immunostaining of thrombomodulin (CD141). In contrast to the lung, NO-dependent, acetylcholine-induced vasodilation, ionophore-stimulated NO2- generation, and production of 6-keto-PGF1α were all impaired in aortic rings from db/db mice. Although eNOS immunostaining was not changed, that of CD141 was clearly lowered. Interestingly, diabetes-induced nitration of proteins in aorta was higher than that in the lungs. In summary, diabetes induced marked ultrastructural changes in pulmonary endothelium that were associated with the increased permeability of pulmonary microcirculation, impaired NO-dependent vascular function, with compensatory increase in PGI2 production, and increased CD141 expression. In contrast, endothelial dysfunction in the aorta was featured by impaired NO-, PGI2-dependent function and diminished CD141 expression.

Changes in the chemical composition of mineralised teeth in children after antineoplastic treatment.

INTRODUCTION: Chemotherapy, neoplasms, and their complications linked to malabsorption, malnutrition, and metabolic disorders may lead to improper tooth development and frequent severe caries in patients during/after antineoplastic treatment and to a more frequent improper tooth development in patients undergoing chemotherapy during odontogenesis. However, the causes of these abnormalities remain unknown; there are no studies on the impact of antineoplastic treatment and its complications on the chemical composition of mineralised teeth. AIM OF THE STUDY: To compare the chemical composition of mineralised teeth extracted due to complicated caries in children after chemotherapy, and of teeth extracted due to orthodontic treatment in generally healthy children. MATERIAL AND METHODS: The treatment group included five teeth extracted due to complicated caries in children after antineoplastic treatment. The control group included five teeth extracted due to orthodontic treatment in generally healthy children. The chemical composition of enamel, dentine, cementum, interior of the canal, and enamel abnormalities in teeth extracted from patients after chemotherapy and in generally healthy patients were assessed with energy-dispersive X-ray spectroscopy. Results were analysed statistically. RESULTS: The magnesium (Mg) and zinc (Zn) mass contents in the enamel of patients after chemotherapy increased and so did the calcium (Ca) to phosphorus (P) ratio when compared to controls. Areas with abnormal enamel in patients after chemotherapy had lower concentrations of Ca and P, and higher concentrations of trace elements (Mg, Cl, and Na). The levels of the assessed elements in dentine, cementum, and inside the canal were similar in both groups of teeth.

Intestinal epithelium, intraepithelial lymphocytes and the gut microbiota - Key players in the pathogenesis of celiac disease.

Celiac disease (CD) is a chronic immune-mediated disorder triggered by the ingestion of gluten in genetically predisposed individuals. Before activating the immune system, gluten peptides are transferred by the epithelial barrier to the mucosal lamina propria, where they are deamidated by intestinal tissue transglutaminase 2. As a result, they strongly bind to human leucocyte antigens (HLAs), especially HLA-DQ2 and HLA-DQ8, expressed on antigen-presenting cells. This induces an inflammatory response, which results in small bowel enteropathy. Although gluten is the main external trigger activating both innate and adaptive (specific) immunity, its presence in the intestinal lumen does not fully explain CD pathogenesis. It has been hypothesized that an early disruption of the gut barrier in genetically susceptible individuals, which would result in an increased intestinal permeability, could precede the onset of gluten-induced immune events. The intestinal barrier is a complex functional structure, whose functioning is dependent on intestinal microbiota homeostasis, epithelial layer integrity, and the gut-associated lymphoid tissue with its intraepithelial lymphocytes (IELs). The aim of this paper was to review the current literature and summarize the role of the gut microbiota, epithelial cells and their intercellular junctions, and IELs in CD development.

Hybrid a-CNH+TiO2+TiN-type surface layers produced on NiTi shape memory alloy for cardiovascular applications.

AIM: The goal was to improve the properties of NiTi shape memory alloy to make it suitable for cardiac applications. For this purpose, a hybrid a-CNH+TiO2+TiN-type surface layer was produced on NiTi alloy and characterized. MATERIALS & METHODS: The NiTi alloy subjected to hybrid process combining low-temperature oxynitriding under glow discharge conditions and radio frequency chemical vapor deposition process was examined for microstructure, surface topography, corrosion resistance, wettability and surface-free energy, Ni ion release and platelets adhesion, aggregation and activation. RESULTS: The hybrid surface layers showed slightly increased surface roughness, better corrosion resistance, a more hydrophobic nature, decreased surface free energy, smaller release of nickel ions and reduced platelets activation. CONCLUSION: The produced layers could expand the range of NiTi medical applications.

Autophagy in Hepatocytes in Infants With Alpha-1 ATD and Different Liver Disease Outcomes: A Retrospective Analysis.

OBJECTIVES: It is unclear whether a distinct activity of pathways removing the antitrypsin (AT) protein in Alpha-1-Antitrypsin Deficiency (α1ATD) are associated with an unfavorable predisposition to liver disease in the future. The aim of this study was to determine whether liverspecific activity of AT protein disposal occurs at infancy in α1ATD with PiZZ phenotype (ATZ). METHODS: Liver samples of 17 infants with unfavorable ATZ outcome (Group I, n = 8, median age  = 0.35 year) and good outcome (Group II, n = 9, 0.17 year), and 9 with biliary atresia (BA, median age = 0.17 year) as control, were enrolled. For each subject were investigated autophagy activity by mRNA, protein expression (Calnexin, Beclin-1, p62, and Parkin), and hepatocyte ultrastructure with morphometric analyses. RESULTS: No significant differences in gene expression in the liver of infants were found between the 2 ATZ groups. Although a correlation between patients' age and protein expression was observed, the ATZ groups differed Parkin immunohistochemical expression. Moreover, the hepatocytes in ATZ infants with unfavorable outcome were characterized by low Parkin expression and the presence of isolated mitophagosoms and numerous enlarged mitochondria. The mentioned findings differed in patients with BA. CONCLUSIONS: Thus, mentioned specific features occurring at infancy may suggest association with poor liver outcome. Parkin low expression could have a potential for disease prognosis and treatment; however, further studies in a greater number of patients are needed.

Vasculogenesis and Its Cellular Therapeutic Applications.

Vasculogenesis was originally defined by Risau in 1997 [Nature 386: 671-674] as the de novo formation of vessels from endothelial progenitor cells (EPCs), so-called angioblasts. Initially, this process was believed to be related only to embryonic life; however, further studies reported vasculogenesis to occur also in adult tissues. This overview presents the current knowledge about the origin, differentiation and significance of EPCs that have been observed in various diseases, tumors, and reparative processes. We also summarize the knowledge of how to activate these cells for therapeutic purposes and the outcomes of the therapies.

Narrow time window of metabolic changes associated with transition to overt heart failure in Tgaq*44 mice.

BACKGROUND: The timing and consequences of alternations in substrate utilization in heart failure (HF) and their relationship with structural changes remain unclear. This study aimed to analyze metabolic changes associated with transition to overt heart failure in transgenic mouse model of HF resulting from cardiac-specific overexpression of constitutively active Gαq*. METHODS: Structural changes quantified by morphometry, relative cardiac mRNA and protein expression of PPARα, FAT/CD36, CPT-1, GLUT-4 and glycolytic efficiency following administration of 1-(13)C glucose were investigated in 4-14-month-old Tgαq*44 mice (TG), compared with age-matched FVB wild type mice (WT). RESULTS: Initial hypertrophy in TG (4-10-month of age) was featured by an accelerated glycolytic pathway that was not accompanied by structural changes in cardiomyocytes. In 10-month-old TG, cardiomyocyte elongation and hypertrophic remodeling and increased glycolytic flux was accompanied by relatively low expression of FAT/CD36, CPT-1 and PPARα. During the transition phase (12-month-old TG), a pronounced increase in PPARα with an increase in relative fatty acid (FA) flux was associated with anomalies of cardiomyocytes with accumulation of lipid droplets and glycogen as well as cell death. At the stage of overt heart failure (14-month-old TG), an accelerated glycolytic pathway with a decline in FA oxidation was accompanied by further structural changes. CONCLUSION: Tgαq*44 mice display three distinct phases of metabolic/structural changes during hypertrophy and progression to HF, with relatively short period of increase in FA metabolism, highlighting a narrow metabolic changes associated with transition to overt heart failure in Tgaq*44 mice that have therapeutic significance.

Reactive oxygen species are involved in insulin-dependent regulation of autophagy in primary rat podocytes.

Autophagy is an intracellular defense mechanism responsible for the turnover of damaged or non-functional cellular constituents. This process provides cells with energy and essential compounds under unfavorable environmental conditions-such as oxidative stress and hyperglycemia, which are both observed in diabetes. The most common diabetes complication is diabetic nephropathy (DN), which can lead to renal failure. This condition often includes impaired podocyte function. Here we investigated autophagic activity in rat podocytes cultured with a high insulin concentration (300nM). Autophagy was activated after 60min of insulin stimulation. Moreover, this effect was abolished following pharmacological (apocynin) or genetic (siRNA) inhibition of NAD(P)H oxidase activity, indicating that insulin-dependent autophagy stimulation involved reactive oxygen species (ROS). We also observed a continuous and time-dependent increase of podocyte albumin permeability in response to insulin, and this process was slightly improved by autophagy inhibition following short-term insulin exposure. Our results suggest that insulin may be a factor affecting the development of diabetic nephropathy.