Folic acid antioxidant supplementation to binge drinking adolescent rats improves hydric-saline balance and blood pressure, but fails to increase renal NO availability and glomerular filtration rate.

Binge drinking (BD) is an especially pro-oxidant pattern of alcohol consumption, particularly widespread in the adolescent population. In the kidneys, it affects the glomerular filtration rate (GFR), leading to high blood pressure. BD exposure also disrupts folic acid (FA) homeostasis and its antioxidant properties. The aim of this study is to test a FA supplementation as an effective therapy against the oxidative, nitrosative, and apoptotic damage as well as the renal function alteration occurred after BD in adolescence. Four groups of adolescent rats were used: control, BD (exposed to intraperitoneal alcohol), control FA-supplemented group and BD FA-supplemented group. Dietary FA content in control groups was 2 ppm, and 8 ppm in supplemented groups. BD provoked an oxidative imbalance in the kidneys by dysregulating antioxidant enzymes and increasing the enzyme NADPH oxidase 4 (NOX4), which led to an increase in caspase-9. BD also altered the renal nitrosative status affecting the expression of the three nitric oxide (NO) synthase (NOS) isoforms, leading to a decrease in NO levels. Functionally, BD produced a hydric-electrolytic imbalance, a low GFR and an increase in blood pressure. FA supplementation to BD adolescent rats improved the oxidative, nitrosative, and apoptotic balance, recovering the hydric-electrolytic equilibrium and blood pressure. However, neither NO levels nor GFR were recovered, showing in this study for the first time that NO availability in the kidneys plays a crucial role in GFR regulation that the antioxidant effects of FA cannot repair.

Selenium, selenoproteins and cancer of the thyroid.

Selenium is an essential mineral element with important biological functions for the whole body through incorporation into selenoproteins. This element is highly concentrated in the thyroid gland. Selenoproteins provide antioxidant protection for this tissue against the oxidative stress caused by free radicals and contribute, via iodothyronine deiodinases, to the metabolism of thyroid hormones. It is known that oxidative stress plays a major role in carcinogenesis and that in recent decades there has been an increase in the incidence of thyroid cancer. The anti-carcinogenic action of selenium, although not fully understood, is mainly attributable to selenoproteins antioxidant properties, and to the ability to modulate cell proliferation (cell cycle and apoptosis), energy metabolism, and cellular immune response, significantly altered during tumorigenesis. Researchers have suggested that different forms of selenium supplementation may be beneficial in the prevention and treatment of thyroid cancer; however, the studies have several methodological limitations. This review is a summary of the current knowledge on how selenium and selenoproteins related to thyroid cancer.

Selenium, a dietary-antioxidant with cardioprotective effects, prevents the impairments in heart rate and systolic blood pressure in adolescent rats exposed to binge drinking treatment.

BACKGROUND: Binge drinking (BD) during adolescence is related to cardiovascular alterations. Selenium (Se) is an essential trace element with antioxidant, anti-inflammatory and antiapoptotic properties, essential for correct heart function. OBJECTIVES: To study the protective cardiovascular effects of selenium in adolescent rats exposed to a BD-like procedure. METHODS: 32 adolescent male rats exposed to an intraperitoneally BD-like model or not, and supplemented with 0.4ppm of selenite or not, were divided into 4 groups: control, alcohol, control-selenium and alcohol-selenium. Blood pressure and heart rate (HR) were determined after experimentation. Se deposits, oxidative balance and the expression of glutathione peroxidases (GPxs), NF-kB and caspase-3 were measured in the heart. Also, DNA instability in rat lymphocytes and serum vascular markers were determined. Statistical analysis was performed with the ANOVA model. RESULTS: The BD-like model depleted Se heart deposits (p < .01), decreased GPx activity (p < .01) and GPx1 (p < .001) and GPx4 (p < .05) expression, increased NF-kB (p < .01), caspase-3 (p < .001) expression, and generated oxidation in myocytes. Outside the heart, the BD-like model caused double-strand breaks in lymphocyte DNA and increased all the vascular markers measured. These cardiovascular alterations were related to higher systolic (p < .001) and diastolic (p < .05) blood pressure and HR (p < .05). In the heart, Se supplementation in BD-exposed rats significantly increased Se deposits (p < .001) and improved oxidative balance and vascular damage, including increased GPxs and decreased NF-kB and caspase-3 activation, consequently decreasing systolic (p < .05) blood pressure and HR (p < .01). CONCLUSIONS: Se supplementation presents cardioprotective effects since it reversed HR and systolic blood pressure observed in BD-exposed adolescent rats.

Selenite supplementation modulates the hepatic metabolic sensors AMPK and SIRT1 in binge drinking exposed adolescent rats by avoiding oxidative stress.

Binge drinking (BD) is the main alcohol consumption pattern among teenagers. Recently, oxidative stress (OS) generated by BD exposure has been related to hepatic metabolic deregulation and cardiovascular dysfunction. This study analyzed if BD by generating oxidative stress modulates the alteration in hepatic energy homeostasis through two important regulators of energy metabolism: the NAD+-dependent sirtuin deacetylase (SIRT1) and AMP-activated protein kinase (AMPK) and if supplementation with the antioxidant selenium (Se) improves these metabolic disorders. Four groups of adolescent rats supplemented or not with Se (0.4 ppm) and exposed to intermittent i.p. BD were used. BD rats showed an increased AST/ALT ratio, total bilirubin in serum and lipid peroxidation in the liver. The BD rats also showed a higher abdominal/thoracic ratio and increased levels of TG, gluc, and chol compared to the control group, provoking an increase in mean blood pressure (MBP). This alcohol consumption pattern decreased hepatic Se deposits, cytoplasmic GPx activity, and GSH levels as well as the expressions of two metabolic sensors and the pAMPK/AMPK ratio. Se supplementation restored antioxidant parameters and decreased lipid oxidation, avoiding OS and improving the hepatic expression of pAMPK and SIRT1, contributing to the improvement of metabolic (better lipid profile and IRS-1 expression) and vascular function (lower MBP), and to the increase of hepatic functionality (lower AST/ALT ratio). All these actions decrease cardiometabolic risk factor development in the short and long term and could disrupt the relationship between BD and MS, two problems which are currently affecting adolescents.

Binge drinking during adolescence disrupts Se homeostasis and its main hepatic selenoprotein expression.

BACKGROUND: Binge drinking (BD) is the most common ethanol (EtOH) intake consumption model among teenagers, but little is known about its effects on the liver. During its hepatic metabolism, acute alcohol exposure produces a great amount of reactive oxygen species which contributes to alcohol-induced liver injury. Selenium (Se) plays a key role in antioxidant defense as it forms part of selenoproteins, such as the antioxidant glutathione peroxidases (GPxs) or the selenoprotein P (SelP), synthesized mainly in liver. Chronic EtOH consumption decreases both Se deposits and this tissue's antioxidant activity. METHODS: Two BD administration routes (oral and intraperitoneal) were used in adolescent rats to analyze Se homeostasis; the main hepatic selenoproteins' expression: GPx1, GPx4, and SelP, and their biological roles related to oxidation. Their relationship with inflammatory processes was also determined by analyzing the expression of the transcriptional factor nuclear factor-kappa beta (NF-κB). RESULTS: It has been demonstrated for the first time that BD in adolescents alters Se homeostasis regardless of the administration route employed, despite the fact that the BD oral group ingested less Se in diet. This decrease of Se in serum and liver is directly related to a decrease in serum GPx3 and hepatic GPx1 activity, contributing to the oxidative imbalance found. The depletion of Se detected in liver affects GPx1 expression and, surprisingly, GPx4 expression. This could be related to the lower expression of the transcriptional factor NF-κB in the liver, a key player in the regulation of inflammatory processes. CONCLUSIONS: Due to the above, and to find whether a Se supplementation therapy improves these situations, it would be interesting to explore in more depth the relationship between Se, the high oxidation found, and the depressed immune response reported in BD adolescents.