The effect of DHEA treatment on the oxidative stress and myocardial fibrosis induced by Keshan disease pathogenic factors

Dehydroepiandrosterone in fibrotic interstitial lung disease: a translational study

BACKGROUND

Dehydroepiandrosterone (DHEA) is a precursor sex hormone with antifibrotic properties. The aims of this study were to investigate antifibrotic mechanisms of DHEA, and to determine the relationship between DHEA-sulfate (DHEAS) plasma levels, disease severity and survival in patients with fibrotic interstitial lung diseases (ILDs).

METHODS

Human precision cut lung slices (PCLS) and normal human lung fibroblasts were treated with DHEA and/or transforming growth factor (TGF)-β1 before analysis of pro-fibrotic genes and signal proteins. Cell proliferation, cytotoxicity, cell cycle and glucose-6-phosphate dehydrogenase (G6PD) activity were assessed. DHEAS plasma levels were correlated with pulmonary function, the composite physiologic index (CPI), and time to death or lung transplantation in a derivation cohort of 31 men with idiopathic pulmonary fibrosis (IPF) and in an independent validation cohort of 238 men and women with fibrotic ILDs.

RESULTS

DHEA decreased the expression of pro-fibrotic markers in-vitro and ex-vivo. There was no cytotoxic effect for the applied concentrations, but DHEA interfered in proliferation by modulating the cell cycle through reduction of G6PD activity. In men with IPF (derivation cohort) DHEAS plasma levels in the lowest quartile were associated with poor lung function and higher CPI (adjusted OR 1.15 [95% CI 1.03-1.38], p = 0.04), which was confirmed in the fibrotic ILD validation cohort (adjusted OR 1.03 [95% CI 1.00-1.06], p = 0.01). In both cohorts the risk of early mortality was higher in patients with low DHEAS levels, after accounting for potential confounding by age in men with IPF (HR 3.84, 95% CI 1.25-11.7, p = 0.02), and for age, sex, IPF diagnosis and prednisone treatment in men and women with fibrotic ILDs (HR 3.17, 95% CI 1.35-7.44, p = 0.008).

CONCLUSIONS

DHEA reduces lung fibrosis and cell proliferation by inducing cell cycle arrest and inhibition of G6PD activity. The association between low DHEAS levels and disease severity suggests a potential prognostic and therapeutic role of DHEAS in fibrotic ILD.

Combination of zinc and selenium alleviates ochratoxin A-induced fibrosis via blocking ROS-dependent autophagy in HK-2 cells

BACKGROUND

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus and Penicillium. The key target organ of OTA toxicity is the kidney, which has a significant impact on human health. Recently, nutrition regulation is suggested to be an effective protection against mycotoxins contamination. The current study investigated the combined protective effects of zinc and selenomethionine (SeMet) (a major component of organic selenium) on OTA-induced renal fibrosis and their potential mechanisms in human renal proximal tubule epithelial cells (HK-2 cells).

METHODS

Cytotoxicity of different concentrations of OTA, zinc and SeMet on HK-2 cells was detected by cell viability, lactate dehydrogenase (LDH) and apoptotic nuclei assays. The expression of fibrosis biomarkers was detected by Real-Time PCR, western blotting and indirect immunofluorescence assays. The production of reactive oxygen species (ROS) was detected by ROS assay kit. The protein expression of autophagy biomarkers was detected by western blotting assay.

RESULTS

Cytotoxicity was induced by OTA treatment in a dose-dependent manner, and it was attenuated by zinc or SeMet application in HK-2 cells. Zinc or SeMet application also down-regulated the expression of fibrosis biomarkers, and the combination of them displayed better effects. In addition, OTA increased intracellular ROS level and activated autophagy in a dose-dependent manner, and it was reversed by zinc and SeMet combined application. With the treatment of hydrogen peroxide (H₂O₂) or rapamycin (the specific activator of autophagy), the combined protective effects of zinc and SeMet were abolished.

CONCLUSIONS

Zinc and SeMet application alleviated OTA-induced cytotoxicity and fibrosis in HK-2 cells. Combination of them was more effective than its individual application. The present study manifest novel insight about the alleviation of OTA-induced nephrotoxicity by nutrition regulation, and had a guiding effect on the clinical supplementation of nutritional elements.

Association of serum cortisol and dehydroepiandrosterone sulfate (DHEAS) levels with psychological stress in patients with vitiligo

Background/aim

Vitiligo is a depigmentation disorder that leads to serious psychological burden in patients, who are frequently reported to have depression and anxiety. The aim of this study was to investigate the association between stress-related hormone levels and psychological stress in vitiligo.

Materials and methods

In this study 46 vitiligo patients and 46 controls were enrolled; their cortisol, dehydroepiandrosterone sulfate (DHEAS), and cortisol/DHEAS levels were measured. Psychological burden was assessed by the Beck Depression Inventory and Perceived Stress Scale.

Results

Patients and controls did not differ in terms of cortisol, DHEAS, or cortisol/DHEAS. Patients had higher perceived stress than controls but did not differ in terms of depression scores. Correlation analyses revealed that cortisol/DHEAS correlated positively with perceived stress (P = 0.009, r = 0.272). The correlation between cortisol/DHEAS and perceived stress was stronger in the patient group (P = 0.013, r = 0.363) and close to zero among controls. In regression analyses, lower depression and higher perceived stress were shown to predict cortisol/DHEAS values.

Conclusion

Vitiligo patients significantly differed from the healthy population in terms of hormones and psychological distress. There was also an association between perceived stress and cortisol/DHEAS ratio in vitiligo. Abnormality of hormonal response to distress lowers DHEAS, which is known for its antioxidant properties, a possible mechanism for vitiligo development. Another important finding is the significance of using the composite variable cortisol/DHEAS, which seems to be more sensitive to distress than each of its components. We suggest its use in future studies on psychological distress–hormone relationships.

Selenium-Rich Diet Induces Myocardial Structural and Functional Abnormalities by Activating Caspase-9 and Caspase-3 in Gpx-1P198L-Overexpression Transgenic Mice

Background

Selenium (Se) deficiency and supplementation result in multiple effects. GPx-1 (Pro198Leu) polymorphism is associated with Se deficiency. This study aimed to observe associations between Se-deficiency/supplement and GPx-1-198Leu overexpression in myocardial injuries.

Material/Methods

GPx-1P198L transgenic (Tg) mice and non-transgenic wild-type (WT) littermates were divided into Control (CON, 0.1–0.2 mg/kg), Se-deficiency (SD, <0.02 mg/kg), and Se-supplement (SS, 0.4 mg/kg) groups. Cardiac functions were observed with animal M-mode echocardiography. Se level was measured using 2,3-diamino Kenai fluorospectrophotometry. Total cardiac GPx activity was also measured. Myocardial histopathology was determined with HE and Masson’s trichrome staining. Caspase-9 and caspase-3 were measured with Western blot analysis.

Results

In WT Se-deficient mice, cardiac GPx activity was significantly decreased, and was not elevated by overexpression of GPx-1-198Leu gene. Increased GPx activity was observed in WT Se-supplemented mice and Tg Se-supplemented mice (much more). Se deficiency as well as supplementation resulted in cardiac systolic dysfunction, which was not affected by GPx-1-198Leu gene. Se deficiency led to myocardial fibrosis and pathological changes accompanied by increased activation of caspase-9 and caspase-3. Se supplementation significantly reduced pathological changes, as well as caspase-9 and caspase-3 levels in the presence of increased myocardial fibrosis. In Se-deficient mice, GPx-1-198Leu overexpression did not significantly decrease myocardial pathological injuries and fibrosis. In Se-supplemented Tg mice, myocardial fibrosis and caspase-9 level were increased, although pathological injuries and caspase-3 were similar to that in Se-supplemented WT mice.

Conclusions

Se deficiency as well as supplementation induced myocardial structural and functional abnormalities through activation of caspase-9 and caspase-3 in GPx-1P198L overexpression transgenic mice.

Dehydroepiandrosterone: Molecular mechanisms and therapeutic implications in osteoarthritis

Dehydroepiandrosterone (DHEA), a 19-carbon steroid hormone primarily synthesized in the adrenal gland, exerts a chondroprotective effect against osteoarthritis (OA) and has been considered an effective candidate of disease-modifying OA drugs (DMOADs) that slow disease progression. We and others previously demonstrated that DHEA exerted a beneficial effect on osteoarthritic cartilage by positively modulating the balance between anabolic and catabolic factors (e.g., MMPs/TIMP-1, ADAMTS/TIMP-3 and cysteine proteinases/cystatin C), inhibiting catabolic signaling pathways (e.g., Wnt/β-catenin), and suppressing proinflammatory cytokines-mediated low-grade synovial inflammation (e.g., IL-1β). However, the full picture of the pharmacological molecular mechanism(s) underlying the activity of DHEA against OA is still incomplete, and a comprehensive and up-to-date review article in this field is unavailable. In this review, recent findings (apart from the well documented pathogenesis of OA) regarding disease-related mechanisms involving low grade synovial inflammation, cartilage matrix stiffness, chondrocyte autophagy and the roles of a variety of catabolic cellular signaling pathways are discussed. Moreover, the possible relationship between these disease-related mechanisms and DHEA action is discussed. Emerging evidence from in vivo and in vitro studies were scrutinized and are concisely presented to demonstrate the investigational and putative mechanisms underlying the anti-OA potential of DHEA.

Sex hormone levels and change in left ventricular structure among men and post-menopausal women: The Multi-Ethnic Study of Atherosclerosis (MESA)

OBJECTIVE

Sex hormone (SH) levels may contribute to sex differences in the risk of heart failure with preserved ejection fraction (HFpEF). We examined the associations of SH levels with left ventricular mass (LVM) and mass (M):volume (V) ratio, which are risk markers for HFpEF.

STUDY DESIGN

We studied 1941 post-menopausal women and 2221 men, aged 45-84 years, participating in the Multi-Ethnic Study of Atherosclerosis (MESA). Serum SH levels, cardiac magnetic resonance imaging (MRI) and ejection fraction (EF) ≥50% had been recorded at baseline (2000-2002). Of these participants, 2810 underwent repeat MRI at Exam 5 (2010-2012). Stratified by sex, linear mixed-effect models were used to test associations between SH and sex hormone binding globulin (SHBG) level [per 1 SD greater log-transformed (SH)] with baseline and change in LV structure. Models were adjusted for age, race/ethnicity, center, height, weight, education, physical activity and smoking, and, in women, for hormone therapy and years since menopause.

MAIN OUTCOME MEASURES

LVM and M:V ratio.

RESULTS

After a median of 9.1 years, higher free testosterone levels were independently associated with a modest increase in LVM (g/yr) in women [0.05 (95% CI 0.01, 0.10)] and men [0.16 (0.03, 0.28)], while higher SHBG levels were associated with less LVM change (g/yr) in women [-0.07 (-0.13, -0.01)] and men [-0.15 (-0.27, -0.02)]. In men, higher dehydroepiandrosterone and estradiol levels were associated with increased LVM. Among women, free testosterone levels were positively and SHBG levels inversely associated with change in M:V ratio.

CONCLUSION

A more androgenic profile (higher free testosterone and lower SHBG levels) is associated with a greater increase in LVM in men and women and greater increase in M:V ratio in women over the course of 9 years.

Selenium modulates MMP2 expression through the TGFβ1/Smad signalling pathway in human umbilical vein endothelial cells and rabbits following lipid disturbance

BACKGROUND

A high-fat diet is a major risk factor for coronary heart diseases. Matrix metalloprotease (MMP) expression is changed in many cardiovascular diseases. Selenium, which is an important trace element in animals, has a close relationship with cardiovascular diseases. The TGFβ1/Smad signalling pathway is ubiquitous in diverse tissues and cells, and it is also associated with the occurrence and development of cardiovascular diseases. Therefore, in this study, we aimed to determine selenium's effect on lipid metabolism, atherosclerotic plaque formation, and MMP2 expression, as well as the underlying functional mechanism.

METHODS AND RESULTS

In vivo tests: 24 male New Zealand white rabbits were randomly divided into 4 groups: regular diet, high-fat diet, high-fat diet+selenium and regular diet+selenium groups. The high-fat diet induced the lipid disturbances of rabbits at week 12. Selenium supplementation lowered total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels (p<0.01). Selenium supplementation also suppressed MMP2 over-expression in thoracic aortas. In vitro tests: Human umbilical vein endothelial cells (HUVECs) were treated with different concentrations of selenium or ox-LDL. Ox-LDL promoted MMP2 expression by increasing TGFβ1, pSmad2, pSmad3 and Smad3 expression (p<0.01). Selenium attenuated MMP2 over-expression by regulating the TGFβ1/Smad signalling pathway.

CONCLUSIONS

Selenium suppressed high-fat diet-induced MMP2 over-expression in vivo by improving lipid metabolism. In vitro, selenium attenuated MMP2 over-expression through the TGFβ1/Smad signalling pathway.

Neurosteroid allopregnanolone attenuates high glucose-induced apoptosis and prevents experimental diabetic neuropathic pain: in vitro and in vivo studies

Hyperglycemia plays a critical role in the development of diabetic neuropathy. Hyperglycemia induces oxidative stress in neurons, resulting in neuronal cell apoptosis and dysfunction. Anti-apoptotic properties of neurosteroids have been demonstrated in numerous cellular models of neurodegenerative studies. Here, the protective effects of neurosteroid allopregnanolone were investigated in in vitro and in vivo models of diabetic neuropathy. The data show that glucose decreased the viability of PC12 cells in a concentration-dependent manner. Allopregnanolone at concentrations of 2.5, 5 and 10μM markedly prevented high glucose-induced toxicity in naïve and NGF-treated (neuron-like) PC12 cells. Furthermore, treatment of diabetic rats with allopregnanolone (5 and 20mg/kg) significantly ameliorated diabetic-induced thermal hyperalgesia. Moreover, this neurosteroid inhibited caspase 3 and decreased Bax/Bcl2 ratio in high glucose-treated cells and spinal cord of diabetic rats. In conclusion, the data revealed that allopregnanolone has protective effects against hyperglycemic-induced cellular damage and prevention of cell apoptosis is involved in its mechanisms. Our findings suggest that allopregnanolone has protective effect against pro-apoptotic challenges such as diabetes and hyperglycemia and propose therapeutic potential of neurosteroids in attenuation of diabetic side effects such as neuropathy.

Dishevelled-1 (Dvl-1) protein: a potential participant of oxidative stress induced by selenium deficiency

Oxidative stress induced by selenium deficiency has been shown to be associated with cardiovascular diseases. Nevertheless, the mechanism associated with oxidative stress induced by selenium deficiency is poorly understood. In the present study, 36 weaning C57BL/6 mice were randomly divided into 4 groups as follows: control (n =9), 4-week selenium deficiency (n =9), 8-week selenium deficiency (n = 9), and 12-week selenium deficiency (n =9). The levels of myocardial glutathione peroxidase (GPx), superoxide dismutase (SOD), and malondialdehyde (MDA) were determined by Western blotting or commercial kits. Real-time PCR was performed to detect the mRNA expression of dishevelled-1 (Dvl-1) protein. Western blotting was conducted to evaluate the protein expression levels of Dvl-1 and β-catenin. Our results demonstrated that the levels of GPx and SOD were significantly reduced, along with an increase in MDA in selenium-deficient mice. Importantly, Dvl-1 and β-catenin were clearly upregulated under oxidative stress. Collectively, our findings indicate that Dvl-1 may be an underlying participant of oxidative stress induced by selenium deficiency.

DHEA inhibits vascular remodeling following arterial injury: a possible role in suppression of inflammation and oxidative stress derived from vascular smooth muscle cells

Vascular remodeling is characterized by the aggregation of vascular smooth muscle cells (VSMCs) in intima. Previous studies have demonstrated that dehydroepiandrosterone (DHEA), a steroid hormone, can reverse vascular remodeling. However, it is still far clear that whether and how DHEA participates in the modulation of VSMCs activation and vascular remodeling. VSMCs were obtained from the thoracic aorta of SD rats. Cell proliferation was evaluated by CCK-8 assay and BrdU assay. To measure VSMCs migration activity, a transwell chamber assay was performed. Quantitative real-time RT-PCR and western blot were used to explore the molecular mechanisms. ROS generation by VSMCs was measured by DCF fluorescence. NADPH oxidase activity and SOD activity were measured by the corresponding kits. NF-κB activity was detected by NF-κB luciferase reporter gene assay. A rat carotid artery balloon injury model was built to evaluate the neointimal formation, and plasma PGF2 was measured by ELISA. Our results showed that DHEA significantly inhibited VSMCs proliferation after angiotensin (Ang II) stimulation by down-regulation of NADPH oxidase activity and ERK1/2 phosphorylation. Ang II can increase IL-6 and MCP-1 expression, but DHEA reverses these changes via inhibiting p38-MAPK/NF-κB (p65) signaling pathway. DHEA has no significant effects on VSMCs phenotype transition, but can reduce the neointimal to media area ratio after balloon injury. DHEA can alleviate oxidative stress and inflammation in VSMCs via ERK1/2 and NF-κB signaling pathway, but has no effect on VSMCs phenotype transition. Furthermore, DHEA attenuates VSMCs activation and neointimal formation after carotid injury in vivo. Taken together, DHEA might be a promising treatment for vascular injury under pathological condition.

Oxidative stress is involved in the pathogenesis of Keshan disease (an endemic dilated cardiomyopathy) in China

Oxidative stress and selenoprotein deficiency are thought to be associated with the pathogenesis of Keshan disease (KD). However, to our knowledge, the level of oxidative stress and expression of selenoproteins have not been investigated in the myocardium of patients with KD. In this study, 8-hydroxy-2-deoxy guanosine (8-OH-dG), a marker of oxidative stress, was used to assess the level of oxidative stress, and thioredoxin reductase 1 (TrxR1) and glutathione peroxidase 1 (GPx1) were assessed to reflect the level of selenoproteins. Myocardial samples from 8 patients with KD and 9 non-KD patients (controls) were immunohistochemically stained for 8-OH-dG, TrxR1, and GPx1. The staining intensities were subsequently quantified using Olympus Image-Pro Plus 6.0 software. The data showed that the positive rate of 8-OH-dG expression in myocardial nuclei was higher in the KD group (68.6%) than that in the control group (2.4%). In addition, a positive correlation between the positive rate of 8-OH-dG and the degree of myocardial damage was observed in the KD group. The distribution of TrxR1 and GPx-1 was not associated with the distribution of myocardial damage. The expression of these two selenoproteins was higher in the control group than that in the KD group. Our study represents the first report on the expression profiles of oxidative stress and selenoproteins in the myocardium of patients with KD. The level of oxidative stress significantly increased and was positively correlated with the degree of myocardial damage in patients with KD. The selenoproteins, TrxR1 and GPx1, may have a role in the pathogenesis of KD.

Role of DHEA in cardiovascular diseases

Dehydroepiandrosterone (DHEA) is a steroid hormone derived from cholesterol synthesized by the adrenal glands. DHEA and its 3β-sulphate ester (DHEA-S) are the most abundant circulating steroid hormones. In human, there is a clear age-related decline in serum DHEA and DHEA-S and this has suggested that a relative deficiency in these steroids may be causally related to the development of a series of diseases associated with aging including cardiovascular diseases (CVD). This commentary aims to highlight the action of DHEA in CVD and its beneficial effect in therapy. We thus discuss the possible impact of serum DHEA decline and DHEA supplementation in diseases such as hypertension, coronary artery disease and atherosclerosis. More specifically, we provide evidence for a beneficial action of DHEA in the main disease of the pulmonary circulation: pulmonary hypertension. We also examine the potential cellular mechanism of action of DHEA in terms of receptors (membrane/nuclear) and associated signaling pathways (ion channels, calcium signaling, PI3K/AKT/eNos pathway, cGMP, RhoA/RhoK pathway). We show that DHEA acts as an anti-remodeling and vasorelaxant drug. Since it is a well-tolerated and inexpensive drug, DHEA may prove to be a valuable molecule in CVD but it deserves further studies both at the molecular level and in large clinical trials.

Both selenium deficiency and modest selenium supplementation lead to myocardial fibrosis in mice via effects on redox-methylation balance

SCOPE

Selenium has complex effects in vivo on multiple homeostatic mechanisms such as redox balance, methylation balance, and epigenesis, via its interaction with the methionine-homocysteine cycle. In this study, we examined the hypothesis that selenium status would modulate both redox and methylation balance and thereby modulate myocardial structure and function.

METHODS AND RESULTS

We examined the effects of selenium-deficient (<0.025 mg/kg), control (0.15 mg/kg), and selenium-supplemented (0.5 mg/kg) diets on myocardial histology, biochemistry and function in adult C57/BL6 mice. Selenium deficiency led to reactive myocardial fibrosis and systolic dysfunction accompanied by increased myocardial oxidant stress. Selenium supplementation significantly reduced methylation potential, DNA methyltransferase activity and DNA methylation. In mice fed the supplemented diet, inspite of lower oxidant stress, myocardial matrix gene expression was significantly altered resulting in reactive myocardial fibrosis and diastolic dysfunction in the absence of myocardial hypertrophy.

CONCLUSION

Our results indicate that both selenium deficiency and modest selenium supplementation leads to a similar phenotype of abnormal myocardial matrix remodeling and dysfunction in the normal heart. The crucial role selenium plays in maintaining the balance between redox and methylation pathways needs to be taken into account while optimizing selenium status for prevention and treatment of heart failure.

Dehydroepiandrosterone inhibits the activation and dysfunction of endothelial cells induced by high glucose concentration

Dehydroepiandrosterone (DHEA), an adrenal steroid, has a protective role against diabetes; however, its mechanisms of action are unknown. Here, we focus on the effect of DHEA on the activation of endothelial cells induced by a high concentration of glucose. Adhesion on U937 cells, expression of adhesion molecules, production of ROS and NO, expression of eNOS, and translocation of NF-κB were evaluated in human umbilical vein endothelial cells (HUVEC) treated with high concentrations of glucose, DHEA, or both. High concentrations of glucose (>20mM) induced an increase in adhesion, an increment in mainly E-selectin and PECAM-1 expression, as well as in ROS and NO production, eNOS expression, translocation of NF-κB, and degradation of its inhibitor IκB-α. DHEA abolished adhesion and the increase of E-selectin, ICAM-1, VCAM-1, and PECAM-1 induced by glucose. In addition, DHEA completely blocked oxidative stress and decreased translocation of NF-κB and the degradation of IκB-α induced by glucose. These results suggest that DHEA protects against the activation of endothelial cells induced by high concentrations of glucose, indicating that DHEA could be useful in the treatment of hyperglycemia and diabetes.