Cholestasis is characterized by the elevation of serum total bile acids (TBA), which leads to the production of both free radicals and oxidative stress. Although they do not share the same mechanisms, membrane glycosphingolipids (GSL) and the antioxidant enzyme heme oxygenase-1 (HMOX1) both act against the pro-oxidative effect of TBA. The aim of the study was to assess the role of HMOX on GSL redistribution and composition within hepatocytes in the rat model of estrogen-induced cholestasis. Compared to the controls, an increase of total gangliosides in the liver homogenates of the cholestatic group (P=0.001) was detected; further, it paralleled along with the activation of their biosynthetic b-branch pathway (P<0.01). These effects were partially prevented by HMOX activation. Cholestasis was accompanied by a redistribution of GM1 ganglioside from the cytoplasm to the sinusoids; while HMOX activation led to the retention of GM1 in the cytoplasm (P=0.014). Our study shows that estrogen-induced cholestasis is followed by changes in the synthesis and/or distribution of GSL. These changes are not only triggered by the detergent power of accumulated TBA, but also by their pro-oxidant action. Increases in the antioxidant defenses might represent an important supportive therapeutic measure for patients with cholestatic liver disease., T. Petr, V. Šmíd, V. Kučerová, K. Váňová, M. Leníček, L. Vítek, F. Šmíd, L. Muchová., and Obsahuje bibliografii
Several authors have reported the association of postprandial hypertriglyceridemia with oxidative stress, systemic inflammation and endothelial dysfunction. Our aim was to investigate the effect of high-calorie meal on blood markers of oxidative stress and endothelial dysfunction and the association of APOA5-1131T/C and -250G/A hepatic lipase (HL) polymorphisms with postprandial triglyceride response. This study included 102 healthy male volunteers. All participants consumed a high-calorie meal (823 calories, 50 g fat, 28 g protein, 60 g carbohydrates). Total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, hsCRP, TAS and ICAM-1 were measured at fasting state and postprandially. APOA5-1131T/C and -250G/A HL polymorphisms were also determined. Postprandial triglycerides were significantly increased (1.4 (1.1-2.1) vs. 2.4 (1.9-3.3) mmol/l, P<0.001). Average triglyceride increase was 1.0±0.7 mmol/l (65 %). Concentration of triglycerides, HDL- cholesterol, LDL-cholesterol, TAS and ICAM-1 differed significantly between the fasting state and postprandial measurements (P<0.001). However, those differences were within the limits of analytical imprecision. Other parameters did not change 3 h after the meal. Triglycerides response did not differ respective to the APOA5 and HL polymorphisms. Family history of hypertension and acut e myocardial infarction were associated with higher postprandial triglyceride concentrations. Postprandial hypertriglyceridemia is not associated with increased concentrations of hsCRP, TAS and ICAM-1. Furthermore, APOA5-1131T/C and -250G/A HL polymorp hisms are not associated with different postprandial triglyceride response., S. Kackov ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Non-alcoholic fatty liver disease (NAFLD) is an important cause of liver-related morbidity and mortality. The aim of this work was to establish and characterize a nutr itional model of NAFLD in rats. Wistar or Sprague-Dawley male rats were fed ad libitum a standard diet (ST-1, 10 % kcal fat), a medium-fat gelled diet (MFGD, 35 % kcal fat) and a high-fat gelled diet (HFGD, 71 % kcal fat) for 3 or 6 weeks. We examined the serum biochemistry, the hepatic malondialdehyde, reduced glut athione (GSH) and cytokine concentration, the respiration of liver mitochondria, the expression of uncoupling protein-2 (UCP-2) mRNA in the liver and histopathological samples. Feeding with MFGD and HFGD in Wistar rats or HFGD in Sprague-Dawley rats induced small-droplet or mixed steatosis without focal infl ammation or necrosis. Compared to the standard diet, there were no significant differences in serum biochemical parameters, except lower concentrations of triacylglycerols in HFGD and MFGD groups. Liver GSH was decreased in rats fed HFGD for 3 weeks in comparison with ST-1. Higher hepatic malondialdehyde was found in both strains of rats fed HFGD for 6 weeks and in Sprague-Dawley groups using MFGD or HFGD for 3 weeks vs. the standard diet. Expression of UCP-2 mRNA was increased in Wistar rats fed MFGD and HFGD for 6 weeks and in Sprague-Dawley rats using HFGD for 6 weeks compared to ST-1. The present stud y showed that male Wistar and Sprague-Dawley rats fed by HFGD developed comparable simple steatosis without signs of progression to non-alcoholic steatohepatitis under our experimental conditions., O. Kučera ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Neuroprotective effects of estrogens and progesterone have been widely studied in various experimental models. The present study was designed to compare possible neuroprotective effects of 17alpha-estradiol, 17beta-estradiol, and progesterone on oxidative stress in rats subjecte d to global cerebral ischemia. Global cerebral ischemia was induced in ovariectomized female rats by four vessel occlusion for 10 min. Following 72 h of reperfusion, levels of malondialdehyde (MDA, oxidative stress marker), and reduced glutathione (GSH, major endogenous antioxidant) were assessed in hippocampus, striatum and cortex of rats treated with either 17alpha-estradiol, 17beta-estradiol, progesterone or estradiol + progesterone beforehand. Steroid administration ameliorated ischemia-induced decrease in GSH and increase in MDA levels. Our data offers additional evidence that estrogens and progesterone or combination of two exert a remarkable neuroprotective effect reducing oxidative stress., V. H. Ozacmak, H. Sayan., and Obsahuje seznam literatury
For more than sixty years lith ium carbonate has been used in medicine. However, during its administration different side effects including oxidative stress can occur. Selenium belongs to essential elements possessing antioxidant properties. This study aimed at evaluating if selenium co uld be used as a protective adjuvant in lithium therapy. The experiment was performed on four groups of Wistar rats: I (control), II (Li), III (Se), IV (Li + Se) treated with saline, lithium carbonate (2.7 mg Li/kg b.w.), sodium selenite (0.5 mg Se/kg b.w.) and lithium carbonate (2.7 mg Li/kg b.w.) + sodium selenite (0.5 mg Se/kg b.w.), respectively. All substances were administered as water solutions by stomach tube for 3 or 6 weeks. Catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GP x) as well as malonyldialdehyde (MDA) were determined in brain homogenates. Lithium slightly enhanced MDA and depressed CAT and SOD after 6 weeks as well as GPx after 3 weeks. Selenium co -administration show ed tendency to restore the disturbed parameters. Selenium alone and given with lithium significantly increased GPx vs. Li- treated group after 3 weeks. Having regarded the outcomes of this study, the research on application of selenium during lithium treatment seems to be worth continuation., M. Kiełczykowska, J. Kocot, A. Lewandowska, R. Żelazowska, I. Musik., and Obsahuje bibliografii
The aim of this study was to determine the effects of insulin infusion on oxidative stress induced by acute changes in glycemia in non-stressed hereditary hypertriglyceridemic rats (hHTG) and Wistar (control) rats. Rats were treated with glucose and either insulin or normal saline infusion for 3 hours followed by 90 min of hyperglycemic (12 mmol/l) and 90 min of euglycemic (6 mmol/l) clamp. Levels of total glutathione (GSH), oxidized glutathione (GSSG) and total antioxidant capacity (AOC) were determined to assess oxidative stress. In steady states of each clamp, glucose infusion rate (GIR) was calculated for evaluation of insulin sensitivity. GIR (mg.kg-1.min-1) was significantly lower in hHTG in comparison with Wistar rats; 25.46 (23.41 - 28.45) vs. 36.30 (27.49 - 50.42) on glycemia 6 mmol/l and 57.18 (50.78 - 60.63) vs. 68.00 (63.61 - 85.92) on glycemia 12 mmol/l. GSH/GSSG ratios were significantly higher in hHTG rats at basal conditions. Further results showed that, unlike in Wistar rats, insulin infusion significantly increases GSH/GSSG ratios in hHTG rats: 10.02 (9.90 - 11.42) vs. 6.01 (5.83 - 6.43) on glycemia 6 mmol/l and 7.42 (7.15 - 7.89) vs. 6.16 (5.74 - 7.05) on glycemia 12 mmol/l. Insulin infusion thus positively influences GSH/GSSG ratio and that way reduces intracellular oxidative stress in insulin-resistant animals., M. Žourek, P. Kyselová, J. Mudra, M. Krčma, Z. Jankovec, S. Lacigová, J. Víšek, Z. Rušavý., and Obsahuje bibliografii a bibliografické odkazy
Ferritin and increased iron stores first appea red on the list of cardiovascular risk factors more than 30 years ago and their causal role in the pathogenesis of atherosclerosis has been heavily discussed since the early 1990s. It seems that besides traditional factors such as hyperlipoprotein emia, hyp ertension, diabetes mellitus, obesity, physical inactivity, smoking and family history, high iron stores represent an additional parameter that could modify individual cardiovascular risk. The role of iron in the pathogenesis of atherosclerosis was origina lly primarily associated with its ability to cataly ze the formation of highly reactive free oxygen radicals and the oxidation of atherogenic lipoproteins. Later, it became clear that the mechanism is more complex. Atherosclerosis is a chronic fibroprolife rative inflammatory process and iron, through increased oxidation stress as well as directly, can control both native and adaptive immune responses. Within the arterial wall, iron affects all of the cell types that participate in the atherosclerotic proces s (monocytes/macrophages, endothelial cells, vascular smooth muscle cells and platelets). Most intracellular iron is bound in ferritin, whereas redox-active iron forms labile iron pool. Pro-inflammatory and anti-inflammatory macrophages within arterial plaque differ with regard to the amount of intracellular iron and most probably with regard to their labile iron pool. Yet, the relation between plasma ferritin and intracellular labile iro n pool has not been fully clarified. Data from population studies document that the consumption of meat and lack of physical activity contribute to increased iron stores. Patients with hereditary h emochromatosis, despite extreme iron storage, do not show i ncreased manifestation of atherosclerosis probably due to the low expression of hepcidin in macrophages., P. Kraml., and Obsahuje bibliografii
Odpřahující protein 2 (UCP2, uncoupling protein 2) objevený v roce 1997 je homologem rozpřahujícího proteinu 1 (UCP1), který byl objeven v mitochondriích hnědé tukové tkáně novorozených savců a dospělých hibernantů jako součást mechanismu netřesové termogeneze. Zatímco UCP1 byl prokázán pouze v hnědé tukové tkáni, UCP2 je exprimován v kosterním svalu, bílé tukové tkáni, plicích a v dalších buněčných populacích. Odpřahující proteiny fungují jako iontové kanály. Jejich otevření snižuje mitochondriální membránový potenciál, tím se snižuje účinnost energetické přeměny – snižuje se tvorba ATP a zvyšuje se uvolnění energie ve formě tepla. UCP proteiny tím, že odpřahují procesy oxidace od tvorby ATP, zvyšují oxidaci substrátů, snižují podíl redukovaných komponent respiračního řetězce a tím redukují produkci reaktivních kyslíkových radikálů mitochondriemi. V tomto článku jsou popsány možné funkce UCP2., Uncoupling protein 2 (UCP2), discovered in 1997, is the fi rst homologue of uncoupling protein 1 (UCP1) that was discovered in mitochondria of brown adipose tissue of newborn mammals and adult hibernators as the part of mechanism in non-shivering thermogenesis. While UCP1 was presented only in brown adipose tissue, UCP2 is expressed in skeletal muscle, white adipose tissue, lungs and in other cell populations. Uncoupling proteins work as ion channels. Opening of these channels decrease the mitochondrial membrane potential thereby the effi ciency of energy conversion is decreased – it is decreased production of ATP and is increased dissipation of energy in the form of heat. Uncoupling proteins uncouple the process of oxidation from the ATP formation, increase the substrate oxidation and decrease the part of reduced components of respiratory chain thereby reducing the production of reactive oxygen species in mitochondria. In this review possible functions of UCP2 are also described., Bolehovská R., Červinková Z., Pospíšilová M., Lotková H., Plíšková L., Palička V., and Lit.: 24
Fyzická aktivita je nedílnou součástí léčby diabetes mellitus 1. typu (DM1T) a diabetes mellitus 2. typu (DM2T). Program pravidelné fyzické aktivity přizpůsobený přítomným komplikacím je doporučován všem diabetikům. Diabetes mellitus se stal problémem také moderní kardiologie a zcela specifickým onemocněním, zvláště pro unikátní vývoj akcelerované aterosklerózy. Dlouhodobý trénink vyvolává dlouhodobé pozitivní účinky na glykemii a inzulinovou senzitivitu. Je nepochybné, že fyzická aktivita hraje klíčovou roli v regulaci tělesné hmotnosti a redukci tukových zásob u diabetiků se všemi příznivými důsledky, v terapii i prevenci metabolického syndromu, manifestaci diabetu i snížení metabolického a kardiovaskulárního rizika u diabetiků. Přestože má fyzická aktivita u diabetu mimořádně příznivé účinky na organizmus, má také svá úskalí ? rizika, o kterých by měl být pacient poučen. Rizika při akutní zátěži se týkají především pacientů s medikamentózní terapií. Možným komplikacím spojeným s fyzickou zátěží je nutno předcházet vhodnou edukací pacientů. Přibývá nesporných dokladů o tom, že pravidelná fyzická aktivita přispívá k primární a sekundární prevenci u metabolického syndromu, diabetu, zvláště diabetu 2. typu a obezity, a je spojena se sníženým rizikem předčasné smrti. Ukázalo se, že fyzická aktivita zlepšuje tělesnou kompozici. Souhrnně lze říci, že pouze určitá kvalitativně i kvantitativně přesně determinovaná, individuálně koncipovaná a pravidelně prováděná tělesná zátěž může u poučeného pacienta plnit léčebný záměr. Programy fyzické aktivity by měly oslovovat všechny věkové skupiny diabetiků, jelikož rizika chronických onemocnění, zvláště kardiovaskulárních, u diabetiků s věkem stoupají., Jaroslav Rybka, and Lit. 10