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.

Hypertension in Polycystic Ovary Syndrome: Novel Insights.

Polycystic ovary syndrome (PCOS) is a common endocrine disease in women during reproductive age. It was shown that PCOS women are with high risk for dyslipidemia, glucose intolerance, type 2 diabetes and metabolic syndrome. These factors are considered to represent traditional risk factors for the occurrence of cardiovascular disease. Observed increased risk for hypertension in PCOS women seems to be associated with insulin resistance and hyperinsulinemia. Both conditions interfere with the endothelium-dependent vasodilatation mechanisms causing vascular muscle wall hypertrophy. Obesity and insulin resistance are considered key factors for the alteration of blood pressure in PCOS women. Higher cardiovascular risk is implicated in PCOS with aging and its consequent association with both systolic and diastolic blood pressure. The elements of renin-angiotensin-aldosterone system (RAAS) have an impact on endothelial dysfunction as a marker of cardiovascular damage that could be modified is women with PCOS. Androgens and components of RAAS are involved in the process of atherogenesis in PCOS women. Therefore, it is hypothesized that spironolactone treatment could ameliorate endothelial dysfunction in PCOS women. Recently it was shown that telmisartan, angiotensin II receptor antagonist poses insulinsensitizing capacity to activate PPAR gamma and mediate favorable metabolic and reproductive effects in hypertensive PCOS women.

A decade in female reproduction: an endocrine view of the past and into the future.

Over the last decade, huge achievements have been made in the fields of neurophysiology, molecular endocrinology, and biochemistry, as well as in the successful translation of clinical research into diseases into clinical practice. As regards female reproduction, most of the advances made in this area were achieved in gonadal axis regulation, regulation of behavior through sex steroids, reproductive genetics, preservation of ovarian reproductive function, steroid profiling, and metabolic and overall reproductive outcomes. The coming years are expected to bring further understanding of the relationships between nutrition, energy metabolism, and reproductive function and to succeed in identifying new genetic markers linked to adverse metabolic and unfavorable cardiovascular outcomes in women. From our perspective, future research in the field of female reproduction should be directed toward doing research into genetic reproductive abnormalities and neuroendocrine diseases, pathophysiology, long-term health outcomes for oligo/amenorrhea, hyperandrogenism, and ovulatory dysfunction. It is additionally expected that a better understanding will be gained of the endocrinology of the placenta and of pregnancy, the role of the microbiome in female reproduction, the role of insulin sensitizers, anti-obesity and anti-diabetic drugs, and various advances in the prevention of ovarian damage caused by various oncology therapies, while new therapeutic options for the treatment of infertility, including kisspeptin, will be developed.

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.

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.

Cortisol Response to Low-dose (1 µg) ACTH Stimulation for the Prediction of Outcome in Patients with Systemic Inflammatory Response Syndrome.

BACKGROUND: Systemic inflammatory response syndrome (SIRS) changes cortisol dynamics and indicates dissociation between the adrenal cortex and the hypothalamo-pituitary unit. The aim of this study was to assess the cortisol response after stimulation with ACTH1-24 in patients with SIRS at admission to the Respiratory Intensive Care Unit (RICU) and seven days later. METHODS: Fifty-four subjects were included in the study, and SIRS was defined according to the Consensus Conference criteria from 1992. Severity of the disease was determined using the APACHE II score, and organ dysfunction using the SOFA score. Low-dose (1, µg) ACTH test (LDT) was performed in all patients, and cortisol was determined along with basal ACTH. Data were analyzed using parametric and nonparametric tests and regression analysis. The results are presented as mean± standard deviation, and P<0.05 was considered statistically significant. RESULTS: There were no differences in cortisol values between the two LDTs. Cortisol increment lower than 250 nmol/L during the LDT was found in 14/54 (25.9%) subjects at the onset of SIRS. Five out of 54 (9.6%)patients died within 7 days from the onset of SIRS. Female sex and maximal cortisol response (▵ max) on LDT predicted the duration of hospitalization in RICU, while APACHE II and SOFA scores best predicted the duration of hospitalization, mortality outcome as well as overall survival outcome. CONCLUSIONS: A difference was found in A max at the diagnosis of SIRS and seven days later. ▵ max, and primarily the clinical scores APACHE II and SOFA predicted the outcomes of hospitalization and overall survival.

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.

Hepatic inflammation induced by high-fructose diet is associated with altered 11ßHSD1 expression in the liver of Wistar rats.

PURPOSE: High fructose consumption provokes metabolic perturbations that result in chronic low-grade inflammation and insulin resistance. Glucocorticoids, potent anti-inflammatory hormones, have important role in pathogenesis of diet-induced metabolic disturbances. The aim of this study was to examine the link between glucocorticoid metabolism and inflammation in the liver of fructose-fed rats. METHODS: Fructose-fed male Wistar rats consumed 60% fructose solution for 9 weeks. Glucocorticoid prereceptor metabolism and signaling were analyzed by measuring the level of 11ß-hydroxysteroid dehydrogenase type 1 (11ßHSD1) and hexose-6-phosphate dehydrogenase expression, as well as via determination of intracellular corticosterone concentration, glucocorticoid receptor subcellular distribution and expression of its target gene, phosphoenolpyruvate carboxykinase. Nuclear factor kappa B (NFκB), tumor necrosis factor alpha (TNFα) and the level of inhibitory phosphorylation of insulin receptor substrate-1 (IRS-1) on Ser(307) were analyzed as markers of hepatic inflammation. The protein and/or mRNA levels of all examined molecules were assessed by Western blot and/or qPCR. RESULTS: Fructose-rich diet led to an enhancement of 11ßHSD1 protein level in the liver, without affecting intracellular level of corticosterone and downstream glucocorticoid signaling. On the other hand, proinflammatory state was achieved through NFκB activation and increased TNFα expression, while elevated level of inhibitory phosphorylation of IRS-1 was observed as an early hallmark of insulin resistance. CONCLUSION: High-fructose diet does not influence hepatic glucocorticoid signaling downstream of the receptor, permitting development of NFκB-driven inflammation. The alteration in 11ßHSD1 expression is most likely the consequence of enhanced inflammation, finally leading to disruption of insulin signaling in the rat liver.

Enhanced prereceptor glucocorticoid metabolism and lipogenesis impair insulin signaling in the liver of fructose-fed rats.

Overconsumption of fructose, as a highly lipogenic sugar, may profoundly affect hepatic metabolism and has been associated with many components of the metabolic syndrome, particularly with insulin resistance and Type 2 diabetes. In this study, we proposed that high fructose diet may enhance lipogenesis and decrease insulin sensitivity in the liver through dysregulation of glucocorticoid signaling. Therefore, we examined the effects of long-term consumption of 10% fructose solution on triglyceridemia, liver histology and intracellular corticosterone level, as well as on 11ß-hydroxysteroid dehydrogenase type 1 (11ßHSD1) and hexose-6-phosphate dehydrogenase (H6PDH) mRNA and protein levels in the rat liver. Glucocorticoid action was assessed by glucocorticoid receptor (GR) expression and intracellular redistribution. We also analyzed the expression of enzymes involved in gluconeogenesis and lipogenesis, phosphoenolpyruvate carboxykinase (PEPCK) and lipin-1. The results have shown that fructose-rich diet led to increase in 11ßHSD1 and H6PDH protein levels, while hepatic corticosterone concentration remained unchanged. Concomitantly, GR was increasingly accumulated in the cytoplasm, whereas its nuclear level was unchanged and accompanied by diminished PEPCK mRNA level. Elevation of lipin-1 in the liver microsomes suggested that fructose diet led to an increase in lipogenesis and consequently to hypertriglyceridemia. The observed increase of insulin receptor supstrate-1 phosphorylation on Ser(307) represents a hallmark of impaired insulin signaling in the liver of fructose-fed rat and probably is a consequence of the alterations in 11ßHSD1 and lipin-1 levels. Overall, our findings suggest that fructose-rich diet may perturb hepatic prereceptor glucocorticoid metabolism and lipogenesis, resulting in hypertriglyceridemia and attenuated hepatic insulin sensitivity.

Tissue-specific regulation of inflammation by macrophage migration inhibitory factor and glucocorticoids in fructose-fed Wistar rats.

High fructose consumption is commonly associated with insulin resistance, disturbed glucose homeostasis and low-grade inflammation. Increased glucocorticoid production within adipose tissue has been implicated in the pathogenesis of fructose-induced metabolic syndrome. Immunosuppressive actions of glucocorticoids can be counter-regulated by macrophage migration inhibitory factor (MIF), which is recognised as a key molecule in metabolic inflammation. In the present study, we hypothesised that coordinated action of glucocorticoids and MIF can mediate the effects of a high-fructose diet on adipose tissue and liver inflammation. We examined the effects of long-term consumption of a 10% fructose solution on corticosterone (CORT) and MIF levels in rat blood plasma, liver and adipose tissue, as well as MIF and TNF-a mRNA expression and NF-kB activation in the same tissues. The high-fructose diet led to an increase in both CORT and MIF in the adipose tissue, and a highly significant positive correlation between their levels was observed. The attenuated NF-kB activation and unaltered TNF-a mRNA expression noticed in the adipose tissue could be interpreted as an outcome of the opposing actions of CORT and MIF. In contrast to adipose tissue, inflammation in the liver was characterised by NF-kB activation, an increased TNF-a mRNA level and unchanged levels of MIF protein, MIF mRNA and CORT. Overall, these findings suggest that a high-fructose diet differently affects the levels of glucocorticoids and MIF in the adipose tissue and liver, implicating that fructose over-consumption has tissue-specific effects on regulation of metabolic inflammation.

Lymphocyte glucocorticoid receptor expression level and hormone-binding properties differ between war trauma-exposed men with and without PTSD.

OBJECTIVE: Posttraumatic stress disorder (PTSD) has been shown to be associated with altered glucocorticoid receptor (GR) activity. We studied the expression and functional properties of the receptor in peripheral blood mononuclear cells (PBMCs) from non-traumatized healthy individuals (healthy controls; n=85), and war trauma-exposed individuals with current PTSD (n=113), with life-time PTSD (n=61) and without PTSD (trauma controls; n=88). The aim of the study was to distinguish the receptor alterations related to PTSD from those related to trauma itself or to resilience to PTSD. METHODS: Functional status of the receptor was assessed by radioligand binding and lysozyme synthesis inhibition assays. The level of GR gene expression was measured by quantitative PCR and immunoblotting. RESULTS: Current PTSD patients had the lowest, while trauma controls had the highest number of glucocorticoid binding sites (Bmax) in PBMCs. Hormone-binding potential (Bmax/KD ratio) of the receptor was diminished in the current PTSD group in comparison to all other study groups. Correlation between Bmax and KD that normally exists in healthy individuals was decreased in the current PTSD group. Contrasting Bmax data, GR protein level was lower in trauma controls than in participants with current or life-time PTSD. CONCLUSIONS: Current PTSD is characterized by reduced lymphocyte GR hormone-binding potential and by disturbed compensation between Bmax and hormone-binding affinity. Resilience to PTSD is associated with enlarged fraction of the receptor molecules capable of hormone binding, within the total receptor molecule population in PBMCs.

Validation of endogenous controls for gene expression studies in peripheral lymphocytes from war veterans with and without PTSD.

BACKGROUND: Selection of appropriate endogenous control is a critical step in gene expression analysis. The aim of this study was to evaluate expression stability of four frequently used endogenous controls: beta-actin, glyceraldehyde-3-phosphate dehydrogenase, beta2-microglobulin and RNA polymerase II polypeptide A in peripheral blood mononuclear cells from war veterans with and without posttraumatic stress disorder (PTSD). The study was designed as to identify suitable reference gene(s) for normalization of gene expression in peripheral blood mononuclear cells in response to war trauma and/or PTSD. RESULTS: The variability in expression of the four endogenous controls was assessed by TaqMan Real-time RT-PCR in peripheral blood mononuclear cells from: war veterans with current PTSD, those with lifetime PTSD, trauma controls and healthy subjects. Expression stability was analyzed by GeNorm and NormFinder software packages, and by direct comparison of Ct values. Both, GeNorm and NormFinder identified beta-actin and glyceraldehyde-3-phosphate dehydrogenase as a pair of genes with the lowest stability value. CONCLUSIONS: The combination of beta-actin and glyceraldehyde-3-phosphate dehydrogenase appeared to be the most suitable reference for studying alterations in gene expression in peripheral blood mononuclear cells related to vulnerability and resilience to PTSD, as well as to trauma-provoked developing of this disorder and recovery from it. Using glyceraldehyde-3-phosphate dehydrogenase, beta-actin and beta2-microglobulin as individual endogenous controls would provide satisfactory data, while RNA polymerase II polypeptide A could not be recommended.

Mercury stimulates rat liver glucocorticoid receptor association with Hsp90 and Hsp70.

The subject of the present study is the influence of mercury on association of rat liver glucocorticoid receptor (GR) with heat shock proteins Hsp90 and Hsp70. The glucocorticoid receptor heterocomplexes with Hsp90 and Hsp70 were immunopurified from the liver cytosol of rats administered with different doses of mercury. The amounts of co-immunopurified apo-receptor, Hsp90 and Hsp70 were then determined by quantitative Western blotting. The ratio between the amount of heat shock protein Hsp90 or Hsp70 and the amount of apo-receptor within immunopurified heterocomplexes was found to increase in response to mercury administration. On the other hand, the levels of Hsp90 and Hsp70 in hepatic cytosol remained unaltered. The finding that mercury stimulates association of the two heat shock proteins with the glucocorticoid receptor, rendering the cytosolic heat shock protein levels unchanged, suggests that mercury affects the mechanisms controlling the assembly of the receptor heterocomplexes.