Fructose-Rich Diet Attenuates Stress-Induced Metabolic Disturbances in the Liver of Adult Female Rats.

BACKGROUND: Both fructose consumption and chronic stress contribute to the development of metabolic disorders. The consequences of such combination are not fully understood. OBJECTIVE: We investigated whether fructose supplementation and chronic stress synergistically disturb hepatic lipid and glucose metabolism. The role of energy sensing, redox, and inflammatory status during development of metabolic disturbances was investigated. METHODS: Female Wistar rats, aged 2.5 mo, were divided into 4 experimental groups: control (C) fed a standard diet (commercial food and drinking water); fructose (F) fed the same food and 10% fructose solution; stress (S) fed the standard diet and subjected to chronic unpredictable stress and, stress + fructose (SF) combining conditions F and S as above. Stress included daily stressors: cold water forced swimming, physical restraint, cold room, wet bedding, rocking, switching, or tilting cages. After 9 wk, hepatic enzymes and transcription factors involved in gluconeogenesis, lipogenesis, fatty acid oxidation, antioxidative defence, energy sensing, and cytokines were assessed by qPCR, Western blotting, and spectrophotometry and analyzed by 2-factor ANOVA. RESULTS: Fructose increased AMP-activated protein kinase (AMPK) phosphorylation (40%; P < 0.05) and the ratio of inhibitory phosphorylation to total acetyl-CoA carboxylase (46%; P < 0.01), and decreased sterol regulatory element binding protein 1c nuclear translocation by 30% (P < 0.05) in F and SF compared with C rats. Increased phosPck (phoenolpyruvate carboxykinase) (85%) and G6pase(glucose-6-phosphatase) (55%) was observed in S rats (P < 0.05). A 40% decrease in Apob (apolipoprotein B-100) and an increase in hepatic lipids (P < 0.05), together with a double increase in TNF-α (P < 0.001), were observed in S rats, but without liver histopathological changes. These stress effects on lipid accumulation and TNF-α were abolished in SF rats (P < 0.05). CONCLUSIONS: Fructose does not enhance stress effects on hepatic lipid and glucose metabolism but attenuates its effects on hepatic lipid accumulation and inflammation, suggesting that, in female rats, AMPK activation prevails over stress-induced effects.

Decreased Glucocorticoid Signaling Potentiates Lipid-Induced Inflammation and Contributes to Insulin Resistance in the Skeletal Muscle of Fructose-Fed Male Rats Exposed to Stress.

The modern lifestyle brings both excessive fructose consumption and daily exposure to stress which could lead to metabolic disturbances and type 2 diabetes. Muscles are important points of glucose and lipid metabolism, with a crucial role in the maintenance of systemic energy homeostasis. We investigated whether 9-week fructose-enriched diet, with and without exposure to 4-week unpredictable stress, disturbs insulin signaling in the skeletal muscle of male rats and evaluated potential contributory roles of muscle lipid metabolism, glucocorticoid signaling and inflammation. The combination of fructose-enriched diet and stress increased peroxisome proliferator-activated receptors-α and -δ and stimulated lipid uptake, lipolysis and ß-oxidation in the muscle of fructose-fed stressed rats. Combination of treatment also decreased systemic insulin sensitivity judged by lower R-QUICKI, and lowered muscle protein content and stimulatory phosphorylations of insulin receptor supstrate-1 and Akt, as well as the level of 11ß-hydroxysteroid dehydrogenase type 1 and glucocorticoid receptor. At the same time, increased levels of protein tyrosine phosphatase-1B, nuclear factor-κB, tumor necrosis factor-α, were observed in the muscle of fructose-fed stressed rats. Based on these results, we propose that decreased glucocorticoid signaling in the skeletal muscle can make a setting for lipid-induced inflammation and the development of insulin resistance in fructose-fed stressed rats.

Fructose Consumption Affects Glucocorticoid Signaling in the Liver of Young Female Rats.

The effects of early-life fructose consumption on hepatic signaling pathways and their relation to the development of metabolic disorders in later life are not fully understood. To investigate whether fructose overconsumption at a young age induces alterations in glucocorticoid signaling that might contribute to development of metabolic disturbances, we analysed glucocorticoid receptor hormone-binding parameters and expression of its target genes involved in gluconeogenesis (phosphoenolpyruvate carboxykinase and glucose-6-phosphatase) and lipid metabolism (lipin-1), as well as redox and inflammatory status in the liver of female rats subjected to a fructose-rich diet immediately after weaning. The fructose diet increased hepatic corticosterone concentration, 11ß-hydroxysteroid dehydrogenase type 1 level, glucocorticoid receptor protein level and hormone-binding activity, as well as lipin-1 level. The expression of glucose-6-phosphatase was reduced in fructose-fed rats, while phosphoenolpyruvate carboxykinase remained unaltered. The fructose-rich diet increased the level of fructose transporter GLUT2, while the expression of fructolytic enzymes fructokinase and aldolase B remained unaltered. The diet also affected pro-inflammatory pathways, but had no effect on the antioxidant defence system. In conclusion, a fructose-rich diet applied immediately after weaning promoted lipogenesis and enhanced hepatic glucocorticoid signaling, possibly to protect against inflammatory damage, but without an effect on gluconeogenesis and antioxidant enzymes. Yet, prolonged treatment might ultimately lead to more pronounced metabolic disturbances.

Chronic Stress Potentiates High Fructose-Induced Lipogenesis in Rat Liver and Kidney.

SCOPE: Intake of fructose-sweetened beverages and chronic stress (CS) both increase risk of cardiometabolic diseases. The aim is to investigate whether these factors synergistically perturb lipid metabolism in rat liver and kidney. METHODS AND RESULTS: Fractional de novo lipogenesis (fDNL), intrahepatic- and intrarenal-triglycerides (IHTG and IRTG), de novo palmitate (DNPalm) content, FA composition, VLDL-TGs kinetics, and key metabolic gene expression at the end of the feeding and non-feeding phases in rats exposed to standard chow diet, chow diet + CS, 20% liquid high-fructose supplementation (HFr), or HFr+CS are measured. HFr induces hypertriglyceridemia, up-regulates fructose-metabolism and gluconeogenic enzymes, increases IHTG and DNPalm content in IHTG and IRTG, and augments fDNL at the end of the feeding phase. These changes are diminished after the non-feeding phase. CS does not exert such effects, but when combined with HFr, it reduces IHTG and visceral adiposity, enhances lipogenic gene expression and fDNL, and increases VLDL-DNPalm secretion. CONCLUSION: Liquid high-fructose supplementation increases IHTG and VLDL-TG secretion after the feeding phase, the latter being the result of stimulated hepatic and renal DNL. Chronic stress potentiates the effects of high fructose on fDNL and export of newly synthesized VLDL-TGs, and decreases fructose-induced intrahepatic TG accumulation after the feeding phase.

Impact of insulin and glucocorticoid signalling on hepatic glucose homeostasis in the rat exposed to high-fructose diet and chronic stress.

Overconsumption of fructose-enriched beverages and everyday stress are involved in the pathogenesis of metabolic disorders through modulation of hepatic glucose metabolism. The aim of the study was to investigate whether interaction of high-fructose diet and chronic stress alter insulin and glucocorticoid signalling thus affecting hepatic glucose homeostasis. High-fructose diet led to hyperinsulinemia, increased glucose transporter 2 level, elevated protein kinase B (Akt) phosphorylation, increased glucokinase mRNA and phospho-to-total glycogen synthase kinase 3 ratio and decreased expression of gluconeogenic genes. Fructose diet also led to stimulated glucocorticoid prereceptor metabolism, but downstream signalling remained unchanged due to increased glucocorticoid clearance. Stress did not affect hepatic insulin and glucocorticoid signalling nor glucose metabolism, while the interaction of the factors was observed only for glucokinase expression. The results suggest that, under conditions of fructose-induced hyperinsulinemia, suppression of gluconeogenesis and glycogen synthase activation contribute to the maintenance of glucose homeostasis. The increased glucocorticoid inactivation may represent an adaptive mechanism to prevent hyperglycaemia.

Diagnosing adenomyosis with MRI: a prospective study revisiting the junctional zone thickness cutoff of 12 mm as a diagnostic marker.

OBJECTIVES: To assess the diagnostic accuracy of a junctional zone (JZ) thickness of ≥ 12 mm and morphological features of the JZ in MRI in diagnosing adenomyosis in a premenopausal study population. METHODS: This single-center, prospective observational study consecutively enrolled 93 premenopausal women suffering from a benign gynecological condition, from September 2014 to August 2016. Institutional review board approval and written consent were obtained. All participants underwent MRI and hysterectomy with a histopathological examination. MR images were evaluated in a blinded fashion by two independent readers. The maximum junctional zone thickness (JZmax), presence of JZmax ≥ 12 mm, and any irregular appearance of the JZ (defined as irregular outer or inner borders, focal thickening, presence of high-intensity signal foci, or fingerlike indentations at the inner border) were documented, and the diagnostic performance was evaluated with the AUC, chi-square test, and multiple regression. RESULTS: Adenomyosis was histopathologically confirmed in 57 (61%) of the women. JZmax was not positively correlated with adenomyosis diagnosis (AUC = 0.57, p = 0.26) and did not differ significantly between those with and without adenomyosis (10.3 vs 10.1 mm, p = 0.88), nor was a cutoff of JZmax ≥ 12 mm (n = 30/57 (53%) vs n = 16/36 (44%), p = 0.29). The presence of an irregular JZ showed the best association with adenomyosis among the evaluated signs (sensitivity 74% (95% CI, 60, 85); specificity 83% (95% CI, 67, 94) (p < 0.001)). CONCLUSIONS: JZmax was not correlated with adenomyosis in the present premenopausal study population, but direct signs of adenomyosis such as irregularities of the JZ provided a good diagnostic accuracy. KEY POINTS: • Measuring the junctional zone thickness is of limited value for diagnosing adenomyosis with MRI and should not be used for diagnosing adenomyosis in premenopausal women with moderate disease severity. • An irregular appearance of the junctional zone, the presence of myometrial cysts, and adenomyoma appear to provide the highest specificity for diagnosing adenomyosis. • A consensus for the definition and reading of the junctional zone is needed.

Modulation of hepatic inflammation and energy-sensing pathways in the rat liver by high-fructose diet and chronic stress.

PURPOSE: High-fructose consumption and chronic stress are both associated with metabolic inflammation and insulin resistance. Recently, disturbed activity of energy sensor AMP-activated protein kinase (AMPK) was recognized as mediator between nutrient-induced stress and inflammation. Thus, we analyzed the effects of high-fructose diet, alone or in combination with chronic stress, on glucose homeostasis, inflammation and expression of energy sensing proteins in the rat liver. METHODS: In male Wistar rats exposed to 9-week 20% fructose diet and/or 4-week chronic unpredictable stress we measured plasma and hepatic corticosterone level, indicators of glucose homeostasis and lipid metabolism, hepatic inflammation (pro- and anti-inflammatory cytokine levels, Toll-like receptor 4, NLRP3, activation of NFκB, JNK and ERK pathways) and levels of energy-sensing proteins AMPK, SIRT1 and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α). RESULTS: High-fructose diet led to glucose intolerance, activation of NFκB and JNK pathways and increased intrahepatic IL-1ß, TNFα and inhibitory phosphorylation of insulin receptor substrate 1 on Ser307. It also decreased phospho-AMPK/AMPK ratio and increased SIRT1 expression. Stress alone increased plasma and hepatic corticosterone but did not influence glucose tolerance, nor hepatic inflammatory or energy-sensing proteins. After the combined treatment, hepatic corticosterone was increased, glucose tolerance remained preserved, while hepatic inflammation was partially prevented despite decreased AMPK activity. CONCLUSION: High-fructose diet resulted in glucose intolerance, hepatic inflammation, decreased AMPK activity and reduced insulin sensitivity. Chronic stress alone did not exert such effects, but when applied together with high-fructose diet it could partially prevent fructose-induced inflammation, presumably due to increased hepatic glucocorticoids.

Mif deficiency promotes adiposity in fructose-fed mice.

The macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine involved in inflammation, regulation of energy metabolism and glucocorticoid action. Chronic low-grade inflammation may be caused by fructose intake, contributing to visceral adipose tissue (VAT) dysfunction. Since MIF is a known antagonist of glucocorticoid signaling, and deregulated glucocorticoid signaling can contribute to lipid metabolism disturbances, we hypothesized that altered MIF signaling might underlie fructose-induced adiposity through glucocorticoid action. We analyzed physiological and biochemical parameters, adipose tissue histology, insulin sensitivity and lipid metabolism in WT and MIF-/- C57Bl/6J mice consuming 20% fructose solution for 9 weeks. Glucocorticoid prereceptor metabolism and glucocorticoid receptor (GR) protein level were examined in VAT, together with the expression of glucocorticoid-target genes involved in lipid metabolism. The expression of adipogenic and lipogenic transcriptional regulators peroxisome proliferator-activated receptor gamma (PPARG) and sterol regulatory element-binding protein 1c (SREBP1c) was also assessed. Results showed disturbed insulin sensitivity in all MIF-/- mice, regardless of the diet. Mice on fructose diet had increased energy intake, but increased visceral adiposity and enlarged adipocytes were observed only in fructose-fed MIF-/- mice. Increased VAT corticosterone level and 11 beta-hydroxysteroid dehydrogenase type 1, hexose-6-phosphate dehydrogenase and GR protein levels were observed in the same animals, together with induced expression of examined lipogenic genes and accumulation of PPARG and SREBP1c. In conclusion, the results showed that dietary fructose was associated with increased visceral adiposity through activation of GR-regulated lipogenic genes, but only in the absence of MIF, which set the state of hyperinsulinemia and insulin resistance.

Chronic Stress Combined with a Fructose Diet Reduces Hypothalamic Insulin Signaling and Antioxidative Defense in Female Rats.

BACKGROUND: Increased fructose consumption and chronic exposure to stress have been associated with the development of obesity and insulin resistance. In the hypothalamus, a crossroad of stress responses and energy balance, insulin and glucocorticoids regulate the expression of orexigenic neuropeptides, neuropeptide Y (NPY) and agouti-related protein (AgRP), and anorexigenic neuropeptides, proopio-melanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART). OBJECTIVES: We investigated whether chronic stress and fructose diet disrupt these hormonal signaling pathways and appetite control in the hypothalamus, contributing to the development of insulin resistance and obesity. Potential roles of hypothalamic inflammation and oxidative stress in the development of insulin resistance were also analyzed. METHODS: Insulin, glucocorticoid, and leptin signaling, expression of orexigenic and anorexigenic neuropeptides, and antioxidative and inflammatory statuses in the whole hypothalamus of fructose-fed female rats exposed to unpredictable stress for 9 weeks were analyzed using quantitative PCR and Western blotting. RESULTS: Chronic stress combined with a fructose-enriched diet reduced protein content and stimulatory phosphorylation of Akt kinase, and elevated 11ß-hydroxysteroid dehydrogenase 1 and glucocorticoid receptor expression, while alterations in appetite regulation (NPY, AgRP, POMC, CART, leptin receptor, and SOCS3 expression) were not observed. The expression of antioxidative defense enzymes (mitochondrial manganese superoxide dismutase 2, glutathione reductase, and catalase) and proinflammatory cytokines (IL-1ß, IL-6, and TNFα) was reduced. CONCLUSIONS: Our results underline the combination of long-term stress exposure and fructose overconsumption as more detrimental for hypothalamic function than for either of the factors separately, as it enhanced glucocorticoid and impaired insulin signaling, antioxidative -defense, and inflammatory responses of this homeostasis- regulating center.

Involvement of glucocorticoid prereceptor metabolism and signaling in rat visceral adipose tissue lipid metabolism after chronic stress combined with high-fructose diet.

Both fructose overconsumption and increased glucocorticoids secondary to chronic stress may contribute to overall dyslipidemia. In this study we specifically assessed the effects and interactions of dietary fructose and chronic stress on lipid metabolism in the visceral adipose tissue (VAT) of male Wistar rats. We analyzed the effects of 9-week 20% high fructose diet and 4-week chronic unpredictable stress, separately and in combination, on VAT histology, glucocorticoid prereceptor metabolism, glucocorticoid receptor subcellular redistribution and expression of major metabolic genes. Blood triglycerides and fatty acid composition were also measured to assess hepatic Δ9 desaturase activity. The results showed that fructose diet increased blood triglycerides and Δ9 desaturase activity. On the other hand, stress led to corticosterone elevation, glucocorticoid receptor activation and decrease in adipocyte size, while phosphoenolpyruvate carboxykinase, adipose tissue triglyceride lipase, FAT/CD36 and sterol regulatory element binding protein-1c (SREBP-1c) were increased, pointing to VAT lipolysis and glyceroneogenesis. The combination of stress and fructose diet was associated with marked stimulation of fatty acid synthase and acetyl-CoA carboxylase mRNA level and with increased 11ß-hydroxysteroid dehydrogenase type 1 and hexose-6-phosphate dehydrogenase protein levels, suggesting a coordinated increase in hexose monophosphate shunt and de novo lipogenesis. It however did not influence the level of peroxisome proliferator-activated receptor-gamma, SREBP-1c and carbohydrate responsive element-binding protein. In conclusion, our results showed that only combination of dietary fructose and stress increase glucocorticoid prereceptor metabolism and stimulates lipogenic enzyme expression suggesting that interaction between stress and fructose may be instrumental in promoting VAT expansion and dysfunction.

PTSD and depressive symptoms are linked to DHEAS via personality.

BACKGROUND: Research results on dehydroepiandrosterone sulfate ester (DHEAS) in post-traumatic stress disorder (PTSD) are inconsistent. We hypothesized that personality traits could be the confounders of DHEAS levels and disease symptoms, which could in part explain the discrepancy in findings. METHOD: This study was a part of a broader project in which simultaneous psychological and biological investigations were carried out in hospital conditions. 380 male subjects were categorized in four groups: A) current PTSD (n = 132), B) lifetime PTSD (n = 66), C) trauma controls (n = 101), and D) healthy controls (n = 81), matched by age. RESULTS: The level of DHEAS is significantly lower in the current PTSD group than in trauma controls. All groups significantly differ in personality traits Disintegration and Neuroticism (current PTSD group having the highest scores). DHEAS is related to both PTSD and depressive symptoms; however, Structural Equation Model (SEM) shows that the relations are indirect, realized via their confounder - personality trait Disintegration. CONCLUSIONS: According to our project results, DHEAS is the second putative biomarker for trauma-related disorders that fails to fulfil this expectation. It appears to be more directly related to personality than to the disease symptoms (the first one being basal cortisol). Our data promote personality as a biologically based construct with seemingly important role in understanding the mental health status.

Disturbances of systemic and hippocampal insulin sensitivity in macrophage migration inhibitory factor (MIF) knockout male mice lead to behavioral changes associated with decreased PSA-NCAM levels.

Macrophage migration inhibitory factor (MIF) is a multifunctional cytokine well known for its role in inflammation enhancement. However, a growing body of evidence is emerging on its role in energy metabolism in insulin sensitive tissues such as hippocampus, a brain region implicated in cognition, learning and memory. We hypothesized that genetic deletion of MIF may result in the specific behavioral changes, which may be linked tо impairments in brain or systemic insulin sensitivity by possible changes of the hippocampal synaptic plasticity. To assess memory, exploratory behavior and anxiety, three behavioral tests were applied on Mif gene-deficient (MIF-/-) and "wild type" C57BL/6J mice (WT). The parameters of systemic and hippocampal insulin sensitivity were also determined. The impact of MIF deficiency on hippocampal plasticity was evaluated by analyzing the level of synaptosomal polysialylated-neural cell adhesion molecule (PSA-NCAM) plasticity marker and mRNA levels of different neurotrophic factors. The results showed that MIF-/- mice exhibit emphasized anxiety-like behaviors, as well as impaired recognition memory, which may be hippocampus-dependent. This behavioral phenotype was associated with impaired systemic insulin sensitivity and attenuated hippocampal insulin sensitivity, characterized by increased inhibitory Ser307 phosphorylation of insulin receptor substrate 1 (IRS1). Finally, MIF-/- mice displayed a decreased hippocampal PSA-NCAM level and unchanged Bdnf, NT-3, NT-4 and Igf-1 mRNA levels. The results suggest that the lack of MIF leads to disturbances of systemic and hippocampal insulin sensitivity, which are possibly responsible for memory deficits and anxiety, most likely through decreased PSA-NCAM-mediated neuroplasticity rather than through neurotrophic factors.

Enhanced Inflammation without Impairment of Insulin Signaling in the Visceral Adipose Tissue of 5α-Dihydrotestosterone-Induced Animal Model of Polycystic Ovary Syndrome.

Polycystic ovary syndrome is a heterogeneous endocrine and metabolic disorder associated with abdominal obesity, dyslipidemia and insulin resistance. Since abdominal obesity is characterized by low-grade inflammation, the aim of the study was to investigate whether visceral adipose tissue inflammation linked to abdominal obesity and dyslipidemia could lead to impaired insulin sensitivity in the animal model of polycystic ovary syndrome.Female Wistar rats were treated with nonaromatizable 5α-dihydrotestosterone pellets in order to induce reproductive and metabolic characteristics of polycystic ovary syndrome. Glucose, triglycerides, non-esterified fatty acids and insulin were determined in blood plasma. Visceral adipose tissue inflammation was evaluated by the nuclear factor kappa B intracellular distribution, macrophage migration inhibitory factor protein level, as well as TNFα, IL6 and IL1ß mRNA levels. Insulin sensitivity was assessed by intraperitoneal glucose tolerance test and homeostasis model assessment index, and through analysis of insulin signaling pathway in the visceral adipose tissue.Dihydrotestosterone treatment led to increased body weight, abdominal obesity and elevated triglycerides and non-esterified fatty acids, which were accompanied by the activation of nuclear factor kappa B and increase in macrophage migration inhibitory factor, IL6 and IL1ß levels in the visceral adipose tissue. In parallel, insulin sensitivity was affected in 5α-dihydrotestosterone-treated animals only at the systemic and not at the level of visceral adipose tissue.The results showed that abdominal obesity and dyslipidemia in the animal model of polycystic ovary syndrome were accompanied with low-grade inflammation in the visceral adipose tissue. However, these metabolic disturbances did not result in decreased tissue insulin sensitivity.

Fructose and stress induce opposite effects on lipid metabolism in the visceral adipose tissue of adult female rats through glucocorticoid action.

PURPOSE: Daily exposure to stress and excessive fructose intake coincides with the growing rate of obesity and related disorders, to which women are more prone than men. Glucocorticoids, the main regulators of energy balance and response to stress, have been associated with the development of metabolic disturbances. The aim of the present study was to examine the effects of fructose overconsumption and/or chronic stress on glucocorticoid signalization and lipid metabolism in female rat adipose tissue. METHODS: We examined the effects of fructose-enriched diet and chronic unpredictable stress, separately and in combination, on glucocorticoid signaling in terms of 11ß-hydroxysteroid dehydrogenase 1 (HSD1)-catalyzed corticosterone regeneration, glucocorticoid receptor (GR) intracellular distribution, hormone binding and transcriptional regulation of genes involved in lipolysis (hormone-sensitive lipase) and lipogenesis (lipoprotein lipase, acetyl-CoA carboxylase, fatty acid synthase and phosphoenolpyruvate carboxykinase) in the visceral adipose tissue (VAT) of adult female rats. Additionally, the nuclear level of the peroxisomal proliferator-activated receptor γ (PPARγ) was analyzed. RESULTS: The combination of stress and fructose-enriched diet led to an elevation in HSD1 expression and intracellular corticosterone concentration, whereas GR nuclear accumulation was enhanced after separate treatments. Furthermore, fructose was shown to induce the expression of all examined lipogenic genes and nuclear accumulation of PPARγ, thereby stimulating adipogenesis, while stress upregulated HSL, reducing the adipose tissue mass regardless of fructose consumption. CONCLUSIONS: Prolonged overconsumption of fructose and chronic exposure to stress promote opposite effects on lipid metabolism in the VAT of adult female rats and suggest that these effects could be mediated by glucocorticoids.

Fructose-enriched diet induces inflammation and reduces antioxidative defense in visceral adipose tissue of young female rats.

PURPOSE: The consumption of refined, fructose-enriched food continuously increases and has been linked to development of obesity, especially in young population. Low-grade inflammation and increased oxidative stress have been implicated in the pathogenesis of obesity-related disorders including type 2 diabetes. In this study, we examined alterations in inflammation and antioxidative defense system in the visceral adipose tissue (VAT) of fructose-fed young female rats, and related them to changes in adiposity and insulin sensitivity. METHODS: We examined the effects of 9-week fructose-enriched diet applied immediately after weaning on nuclear factor κB (NF-κB) intracellular distribution, and on the expression of pro-inflammatory cytokines (IL-1ß and TNFα) and key antioxidative enzymes in the VAT of female rats. Insulin signaling in the VAT was evaluated at the level of insulin receptor substrate-1 (IRS-1) protein and its inhibitory phosphorylation on Ser307. RESULTS: Fructose-fed rats had increased VAT mass along with increased NF-κB nuclear accumulation and elevated IL-1ß, but not TNFα expression. The protein levels of antioxidative defense enzymes, mitochondrial manganese superoxide dismutase 2, and glutathione peroxidase, were reduced, while the protein content of IRS-1 and its inhibitory phosphorylation were not altered by fructose diet. CONCLUSIONS: The results suggest that fructose overconsumption-related alterations in pro-inflammatory markers and antioxidative capacity in the VAT of young female rats can be implicated in the development of adiposity, but do not affect inhibitory phosphorylation of IRS-1.

Posttraumatic and depressive symptoms in ß-endorphin dynamics.

A disturbed beta-endorphin system can be a part of the post-traumatic stress disorder (PTSD) and depression allostasis. Study subjects (N=392) included those with PTSD and/or (stress-induced) depression, and healthy controls with and without traumas. The aim of the study was to examine the network of relations centered around plasma beta-endorphin. The network included anxiety (as a personality trait), traumatic events, pain, aggressiveness, depressive symptoms, and three clusters of PTSD symptoms: intrusions, avoidance, and hyperarousal. Beta-endorphin was represented by individual mean from 13 time points (BEmean), reflecting the total amount of the peripherally secreted hormone, and the coefficient of variation (BEvar), calculated as the ratio of standard deviation to the mean, reflecting the hormone׳s dynamics. BEvar correlated with all other variables, BEmean had no correlations. Structural equation modeling (SEM) was used to examine all interrelations (including their directions) of BEvar and the state/trait variables in the context of their entirety. The model revealed that hyperarousal and anxiety were the only direct agents of peripheral beta-endorphin fluctuations, mediating the effects of other variables. Traumatic events and intrusions act on BEvar via hyperarousal, while depressive symptoms, avoidance, and pain act via anxiety. Hyperarousal should be emphasized as the main agent not only because its effect on BEvar is larger than that of anxiety, but also because it increases anxiety itself (via avoidance and pain). All influences on BEvar are positive and they indicate long-term (sensitizing) effects (as opposed to direct stimulation, for example, by acute pain, anger, etc.). Relations apart from beta-endorphin are also discussed.

Cardiac fatty acid uptake and metabolism in the rat model of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is associated with an altered plasma lipid profile and increased risk for cardiovascular diseases. We hypothesized that molecular mechanisms underlying cardiac pathology in PCOS involve changes in expression and subcellular localization of several key proteins involved in cardiac lipid transport and metabolism, such as fatty acid transporter CD36, lipin 1, peroxisome proliferator-activated receptor α (PPARα), peroxisome proliferator-activated receptor γ coactivator-1 (PGC1), and carnitine palmitoyltransferase 1 (CPT1). We used the animal model of PCOS obtained by treating female rats with dihydrotestosterone (DHT). Protein levels of CD36, lipin 1, PPARα, PGC1, and antioxidative enzymes were assessed by Western blot in different cardiac cell compartments. Cardiac triglycerides (TG) and lipid peroxidation were also measured. The content of CD36 was decreased in both the cardiac plasma membranes and intracellular pool. On the other hand, total content of cardiac lipin 1 in DHT-treated rats was elevated, in contrast to decreased microsomal lipin 1 content. An increase in nuclear content of lipin 1 was observed together with elevation of nuclear PPARα and PGC1, and an increase in CPT1 expression. However, lipid peroxidation was reduced in the heart, without alterations in antioxidative enzymes expression and cardiac TG content. The results indicate that treatment of female rats with DHT is accompanied by a decrease of fatty acid uptake and a reduction of lipid peroxidation in the heart. The observed elevation of lipin 1, PPARα, PGC1, and CPT1 expression suggests that cardiac fatty acid metabolism is shifted toward mitochondrial beta oxidation.

The expression and activity of antioxidant enzymes in the liver of rats exposed to high-fructose diet in the period from weaning to adulthood.

BACKGROUND: Increased fructose consumption correlates with rising prevalence of various metabolic disorders, some of which were linked to oxidative stress. The relationship between fructose consumption and oxidative stress is complex and effects of a fructose-rich diet on the young population have not been fully elucidated. The aim of this study was to investigate whether high-fructose diet applied in the period from weaning to adulthood induces oxidative stress in the liver, thus contributing to induction or aggravation of metabolic disturbances in later adulthood. To that end we examined the effects of high-fructose diet on expression and activity of antioxidant enzymes, markers of lipid peroxidation and protein damage in the liver as the main fructose metabolizing tissue. RESULTS: High-fructose diet increased only SOD2 (mitochondrial manganese superoxide dismutase) activity, with no effect on other antioxidant enzymes, lipid peroxidation or accumulation of damaged proteins in the liver. CONCLUSION: The results show that fructose-induced metabolic disturbances could not be attributed to oxidative stress, at least not at young age. The absence of oxidative stress in the liver observed herein implies that young organisms are capable of maintaining redox homeostasis when challenged by fructose-derived energy overload.

Possible involvement of glucocorticoids in 5α-dihydrotestosterone-induced PCOS-like metabolic disturbances in the rat visceral adipose tissue.

Polycystic ovary syndrome (PCOS) is a reproductive and metabolic disorder characterized by hyperandrogenism, ovulatory dysfunction, visceral obesity and insulin resistance. We hypothesized that changes in glucocorticoid metabolism and signaling in the visceral adipose tissue may contribute to disturbances of lipid metabolism in the rat model of PCOS obtained by 5α-dihydrotestosterone (DHT) treatment of prepubertal female Wistar rats. The results confirmed that DHT treatment caused anovulation, obesity and dyslipidemia. Enhanced glucocorticoid prereceptor metabolism, assessed by elevated intracellular corticosterone and increased 11 beta-hydroxysteroid dehydrogenase type 1 mRNA and protein levels, was accompanied by glucocorticoid receptor (GR) nuclear accumulation. In concert with the increased expression of GR-regulated prolipogenic genes (lipin-1, sterol regulatory element binding protein 1, fatty acid synthase, phosphoenolpyruvate carboxykinase), histological analyses revealed hypertrophic adipocytes. The results suggest that glucocorticoids influence lipid metabolism in the visceral adipose tissue in the way that may contribute to pathogenesis of metabolic disturbances associated with PCOS.

The influence of combined oral contraceptives containing drospirenone on hypothalamic-pituitary-adrenocortical axis activity and glucocorticoid receptor expression and function in women with polycystic ovary syndrome.

OBJECTIVE: Most women with PCOS have increased adrenal androgen production, enhanced peripheral metabolism of cortisol and elevation in urinary excretion of its metabolites. Increased cortisol clearance in PCOS is followed by a compensatory overdrive of the hypothalamic-pituitary-adrenocortical (HPA) axis. We hypothesized that oral contraceptives containing ethinylestradiol and drospirenone (EE-DRSP) could modulate glucocorticoid receptor (GR) expression and function and thus affect HPA axis activity in PCOS patients. DESIGN: We analyzed 12 women with PCOS (age 24.17±4.88 years; body mass index 22.05±3.97 kg/m²) treated for 12 months with EE-DRSP and 20 BMI matched controls. In all subjects testosterone, dehydroepiandrosterone sulfate (DHEAS), sex hormone binding globulin (SHBG), cortisol (basal and after dexamethasone), concentrations of GR protein, phospo-GR211 protein, number of GR per cell (B(max) and its equilibrium dissociation constant (K(D)) were measured. RESULTS: Before treatment, increased concentrations of testosterone and DHEAS (p<0.001, respectively), unaltered basal cortisol and an increased sensitivity (p<0.05) of the HPA axis to dexamethasone were observed in PCOS women in comparison to controls. After treatment, testosterone (p<0.01), DHEAS (p<0.05) and cortisol suppression after dexamethasone (p<0.01) were decreased in PCOS women. There were no changes in GR protein concentration, GR phosphorylation nor in the receptor functional parameters B(max) and K(D) in women with PCOS before and after the therapy, and in comparison to controls. CONCLUSIONS: Prolonged treatment with EE-DRSP in PCOS women decreased serum androgens and increased cortisol in the presence of decreased sensitivity of the HPA axis and did not exert changes in GR expression and function.