Time-Dependent Alterations in Liver Oxidative Stress due to Ethanol and Acetaldehyde

Binge drinking is a major public health issue and ethanol-related liver insult may play a major role in the pathology of alcoholic liver disease. However, the degree of oxidative stress, cell death and contribution of acetaldehyde to liver damage over a 24-h period has yet to be determined. Herein, we aimed to investigate the effect of acute alcohol and elevated acetaldehyde levels on hepatic oxidative damage, apoptosis, and antioxidant enzyme activity over a 24-h period. Male Wistar rats were divided into four groups and animals were pre-injected (intraperitonially [i.p.]) with either saline (0.15 mol/L) or cyanamide (5-mmol/kg body weight), followed by either saline (0.15 mol/L) or ethanol (75-mmol/kg bodyweight). After 2.5, 6 and 24 h, hepatic cytosolic and mitochondrial fractions were analysed for indices of oxidative stress. At 2.5 h, cytosolic glutathione and malondialdehyde levels were significantly reduced and increased, respectively, with alcohol treatment. Caspase-3 activity and cytochrome c levels were increased with alcohol treatment at 24 h. The combination of cyanamide and alcohol treatment at 24 h led to a significant increase in serum alanine aminotransferase levels, and reduced albumin and total protein levels. Furthermore, glutathione peroxidase activity and glutathione reductase activity were significantly decreased and increased, respectively. Finally, superoxide dismutase activity was decreased in cytosol and increased in the mitochondria after cyanamide and ethanol treatment, respectively. This study indicates a complex differential effect of alcohol and acetaldehyde, whereby alcohol toxicity in the mitochondria takes place throughout the 24-h period, but raised acetaldehyde has a further detrimental effect on liver function

Excessive iron induces oxidative stress promoting cellular perturbations and insulin secretory dysfunction in MIN6 beta cells

Exposure to high levels of glucose and iron are co-related to reactive oxygen species (ROS) generation and dysregulation of insulin synthesis and secretion, although the precise mechanisms are not well clarified. The focus of this study was to examine the consequences of exposure to high iron levels on MIN6 β-cells. MIN6 pseudoislets were exposed to 20 µM (control) or 100 µM (high) iron at predefined glucose levels (5.5 mM and 11 mM) at various time points (3, 24, 48 & 72 h). Total iron content was estimated by a colourimetric ferrozine assay in presence or absence of transferrin-bound iron. Cell viability was assessed by a resazurin dye-based assay, and ROS mediated cellular oxidative stress was assessed by estimating malondialdehyde levels. β-cell iron absorption was de-termined by a ferritin immunoassay. Cellular insulin release and content was measured by an insu-lin immunoassay. Expression of SNAP-25, a key protein in the core SNARE complex that modulates vesicle exocytosis, was measured by immunoblotting. Our results demonstrate that exposure to high iron levels resulted in a 15-fold (48 h) and 4-fold (72 h) increase in cellular iron accumulation. These observations were consistent with data from oxidative stress analysis which demonstrated 2.69-fold higher levels of lipid peroxidation. Furthermore, exposure to supraphysiological (11 mM) levels of glucose and high iron (100 µM) at 72 h exerted the most detrimental effect on the MIN6 β-cell viability. The effect of high iron exposure on total cellular iron content was identical in the pres-ence or absence of transferrin. High iron exposure (100 µM) resulted in a decrease of MIN6 insulin secretion (64% reduction) as well as cellular insulin content (10% reduction). Finally, a significant reduction in MIN6 β-cell SNAP-25 protein expression was evident at 48 h upon exposure to 100 µM iron. Our data suggest that exposure to high iron and glucose concentrations results in cellular ox-idative damage and may initiate insulin secretory dysfunction in pancreatic β-cells by modulation of the exocytotic machinery

Antioxidant and Antidiabetic Properties of a Thinned-Nectarine-Based Nanoformulation in a Pancreatic β-Cell Line

Pancreatic β-cells play a crucial role in maintaining glucose homeostasis, although they are susceptible to oxidative damage, which can ultimately impair their functionality. Thinned nectarines (TNs) have gained increasing interest due to their high polyphenol and abscisic acid (ABA) content, both of which possess antidiabetic properties. Nevertheless, the efficacy of these bioactive compounds may be compromised by limited stability and bioavailability in vivo. This study aimed to develop nanoformulations (NFs) containing pure ABA or a TN extract (TNE) at an equivalent ABA concentration. Subsequently, the insulinotropic and antioxidant potential of the NFs and their unformulated (free) forms were compared in MIN-6 pancreatic cells exposed to varying glucose (5.5 mM and 20 mM) and iron (100 µM) concentrations. NF-TNE treatment exhibited enhanced antioxidant activity compared to free TNE, while ABA-based groups showed no significant antioxidant activity. Moreover, MIN6 cells incubated with both high glucose and iron levels demonstrated significantly higher insulin AUC levels after treatment with all samples, with NF-TNE displaying the most pronounced effect. In conclusion, these results highlight the additional beneficial potential of TNE due to the synergistic combination of bioactive compounds and demonstrate the significant advantage of using a nanoformulation approach to further increase the benefits of this and similar phytobioactive molecules

Characterisation of hepcidin response to holotransferrin treatment in CHO TRVb-1 cells

Iron overload coupled with low hepcidin levels are characteristics of hereditary haemochromatosis. To understand the role of transferrin receptor (TFR) and intracellular iron in hepcidin secretion, Chinese hamster ovary transferrin receptor variant (CHO TRVb-1) cells were used that express iron-response-element-depleted human TFRC mRNA (TFRC∆IRE). Results showed that CHO TRVb-1 cells expressed higher basal levels of cell-surface TFR1 than HepG2 cells (2.2-fold; p < 0.01) and following 5 g/L holotransferrin treatment maintained constitutive over-expression at 24h and 48 h, contrasting the HepG2 cells where the receptor levels significantly declined. Despite this, the intracellular iron content was neither higher than HepG2 cells nor increased over time under basal or holotransferrin-treated conditions. Interestingly, hepcidin secretion in CHO TRVb-1 cells exceeded basal levels at all time-points (p < 0.02) and matched levels in HepG2 cells following treatment. While TFRC mRNA expression showed expected elevation (2h, p < 0.03; 4h; p < 0.05), slc40a1 mRNA expression was also elevated (2 h, p < 0.05; 4 h, p < 0.03), unlike the HepG2 cells. In conclusion, the CHO TRVb-1 cells prevented cellular iron-overload by elevating slc40a1 expression, thereby highlighting its significance in the absence of iron-regulated TFRC mRNA. Furthermore, hepcidin response to holotransferrin treatment was similar to HepG2 cells and resembled the human physiological response

Comprehensive Guide to Autism

Autism is a complex multifaceted disorder affecting neurodevelopment during the early years of life and, for many, throughout the life span. Inherent features include difficulties or deficits in communication, social interaction, cognition, and interpersonal behavioral coordination, to name just a few. Autism profoundly impacts the affected individual, the family, and, in many cases, the localized communities. The increased prevalence of childhood autism has resulted in rapid developments in a wide range of disciplines in recent years. Nevertheless, despite intensive research, the cause(s) remain unresolved and no single treatment strategy is employed. To address these issues, Comprehensive Guide to Autism is an all-embracing reference that offers analyses and discussions of contemporary issues in the field of autism. The work brings together scientific material from leading experts in the field relating to a wide range of important current topics, such as the early identification and treatment of children with autism, pertinent social and behavioral studies, recent developments in genetics and immunology, the influence of diet, models of autism, and future treatment prospects. Comprehensive Guide to Autism contains essential readings for behavioral science researchers, psychologists, physicians, social workers, parents, and caregivers