Early carotid atherosclerosis in normotensive severe obese premenopausal women with low DHEA(S)

Dehydroepiandrosterone reduces accumulation of lipid droplets in primary chicken hepatocytes by biotransformation mediated via the cAMP/PKA-ERK1/2 signaling pathway

Dehydroepiandrosterone (DHEA) is commonly used as a nutritional supplement to control fat deposition, but the mechanism of this action is poorly understood. In this study, we demonstrated that DHEA increased phosphorylation of AMP-activated protein kinase (p-AMPK). Elevated p-AMPK levels resulted in reduced expression of sterol regulatory element binding protein-1c, acetyl CoA carboxylase, fatty acid synthase and enhanced expression of peroxisome proliferators-activated receptor α and carnitine palmitoyl transferase-I, ultimately leading to the reduction of lipid droplet accumulation in primary chicken hepatocytes. We found that DHEA activates the cyclic adenosine 3', 5'-monophosphate/protein kinase A - extracellular signal-regulated kinase 1/2 (cAMP/PKA-ERK1/2) signaling pathway, which regulates the conversion of DHEA into testosterone and estradiol by increasing the 17β-hydroxysteroid dehydrogenase and aromatase protein expression. Importantly, the fat-reducing effects of DHEA are more closely associated with the conversion of DHEA into estradiol than with the action of DHEA itself as an active biomolecule, or to its alternative metabolite, testosterone. Taken together, our results indicate that DHEA is converted into active hormones through activation of the cAMP/PKA-ERK1/2 signaling pathway; the fat-reducing effects of DHEA are achieved through its conversion into estradiol, not testosterone, and not through direct action of DHEA itself, which led to the activation of the p-AMPK in primary chicken hepatocytes. These data provide novel insight into the mechanisms underlying the action of DHEA in preventing fat deposition, and suggest potential applications for DHEA treatment to control fat deposition or as an agent to treat disorders related to lipid metabolism in animals and humans.

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.

Endogenous steroids measured by high-specificity liquid chromatography-tandem mass spectrometry and prevalent cardiovascular disease in 70-year-old men and women

CONTEXT

There is a need for increased knowledge about endogenous sex hormone levels and clinical outcomes of risk/benefit. Immunoassays have poor specificity to reliably measure low steroid concentrations in elderly.

OBJECTIVE

The objective of the study was to evaluate plasma steroid concentrations with regard to prevalent cardiovascular disease (CVD) in elderly, using mass spectrometry.

SETTING

The study was conducted at a university hospital research unit.

DESIGN AND METHODS

Plasma samples were analyzed from 202 70-yr-olds as part of a large population-based study, Prospective Investigation of the Vasculature in Uppsala Seniors. Twenty-eight of these had prevalent CVD. Eleven steroids were quantified, using liquid chromatography-tandem mass spectrometry. Women with current/previous menopausal hormone therapy (n = 35) were excluded.

RESULTS

Men without prevalent CVD had higher plasma 17beta-estradiol (E2), compared with women. Men with prevalent CVD, compared with those without, had lower 17-hydroxypregnenolone (17OHPregn), 17-hydroxyprogesterone, and higher estrone/androstenedione and E2/testosterone (T) (aromatase activity). Women with prevalent CVD had lower pregnenolone, 17OHPregn, and dehydroepiandrosterone (DHEA) but higher DHEA/17OHPregn, androstenedione/DHEA, E2/T, E2/estrone, and E2/SHBG. The aromatase index, E2/T, was higher for prevalent CVD in both sexes. Adjustment for statin use, smoking, and body mass index yielded additional significant differences in men, whereas some were lost in women. Logistic regression indicated strong associations between prevalent CVD and low 17OHPregn, adjusted odds ratio of 0.18, 95% confidence interval (0.06-0.61); P = 0.006, in women and low 17-hydroxyprogesterone, 0.45 (0.25-0.80); P = 0.007 in men, most likely caused by increased throughput (consumption) toward estrogen synthesis.

CONCLUSIONS

Prevalent CVD was associated with indications of lower androgen precursors, increased aromatase activity, and higher estrogen levels in both sexes. Results might represent an endogenous response to a condition of developing atherosclerosis, rather than a causative relationship. Furthermore studies are needed.

Dehydroepiandrosterone reverses systemic vascular remodeling through the inhibition of the Akt/GSK3-{beta}/NFAT axis

BACKGROUND

The remodeled vessel wall in many vascular diseases such as restenosis after injury is characterized by proliferative and apoptosis-resistant vascular smooth muscle cells. There is evidence that proproliferative and antiapoptotic states are characterized by a metabolic (glycolytic phenotype and hyperpolarized mitochondria) and electric (downregulation and inhibition of plasmalemmal K(+) channels) remodeling that involves activation of the Akt pathway. Dehydroepiandrosterone (DHEA) is a naturally occurring and clinically used steroid known to inhibit the Akt axis in cancer. We hypothesized that DHEA will prevent and reverse the remodeling that follows vascular injury.

METHODS AND RESULTS

We used cultured human carotid vascular smooth muscle cell and saphenous vein grafts in tissue culture, stimulated by platelet-derived growth factor to induce proliferation in vitro and the rat carotid injury model in vivo. DHEA decreased proliferation and increased vascular smooth muscle cell apoptosis in vitro and in vivo, reducing vascular remodeling while sparing healthy tissues after oral intake. Using pharmacological (agonists and antagonists of Akt and its downstream target glycogen-synthase-kinase-3beta [GSK-3beta]) and molecular (forced expression of constitutively active Akt1) approaches, we showed that the effects of DHEA were mediated by inhibition of Akt and subsequent activation of GSK-3beta, leading to mitochondrial depolarization, increased reactive oxygen species, activation of redox-sensitive plasmalemmal voltage-gated K(+) channels, and decreased [Ca(2+)](i). These functional changes were accompanied by sustained molecular effects toward the same direction; by decreasing [Ca(2+)](i) and inhibiting GSK-3beta, DHEA inhibited the nuclear factor of activated T cells transcription factor, thus increasing expression of Kv channels (Kv1.5) and contributing to sustained mitochondrial depolarization. These results were independent of any steroid-related effects because they were not altered by androgen and estrogen inhibitors but involved a membrane G protein-coupled receptor.

CONCLUSIONS

We suggest that the orally available DHEA might be an attractive candidate for the treatment of systemic vascular remodeling, including restenosis, and we propose a novel mechanism of action for this important hormone and drug.

Echocardiographic alterations in patients with non-functioning adrenal incidentaloma

OBJECTIVE

While left ventricular (LV) dysfunction has been described in patients with Cushing's syndrome (CS), data concerning morphologic and functional cardiac alterations in patients with incidentally discovered adrenal masses [adrenal "incidentaloma" (AI)], without overt hypercortisolism, are lacking. In this study the echocardiographic characteristics of patients with AI were evaluated and then compared with those of lean and obese normotensive subjects.

SUBJECTS AND METHODS

Twenty-one patients with AI, without clinical or subclinical hypercortisolism, 18 normotensive obese subjects matched for gender and body mass index (BMI) and 20 normotensive lean subjects were studied. Echocardiography was performed in all subjects. In all patients plasma ACTH, serum cortisol, and DHEA-S levels were measured.

RESULTS

Patients with AI showed greater impairment of several echocardiographic indices of LV hypertrophy and diastolic dysfunction compared to normotensive lean subjects (p<0.05), but did not differ from those in obese subjects. Hypertensive AI patients showed a greater alteration of echocardiographic parameters (p<0.05) and higher BMI (p<0.01) and cortisol values (p<0.05) than normotensive ones. Plasma ACTH and serum cortisol were similar in AI patients and in obese controls, while DHEA-S levels were lower in AI (p<0.05). No correlations between cortisol secretion and echocardiographic parameters were found.

CONCLUSION

In patients with non-functioning AI there is an impairment of cardiac morphology and function. These data suggest that patients with AI should be carefully screened also by means of echocardiographic studies.

Role of dehydroepiandrosterone sulfate levels on body composition after laparoscopic adjustable gastric banding in pre-menopausal morbidly obese women

In humans, dehydroepiandrosterone (DHEAS) has been postulated to have anabolic and lipolytic properties that could potentially counteract the catabolic effect of cortisol. DHEAS secretion is reduced in morbid obesity, likely due to hyperinsulinemia, and laparoscopic adjustable gastric banding (LASGB), by inducing considerable and rapid weight loss, reduces insulin levels. To investigate the role of decreased insulin levels after LASGB-induced weight loss on DHEAS levels and on body composition changes, we studied 30 pre-menopausal morbidly obese women (BMI ranging 37-62 kg/m2) before, 6, 12 and 24 months after LASGB. Total body water (TBW), fat-free mass (FFM) and fat mass (FM) were measured by bioelectrical impedance analysis; tissue hydration was also assessed by impedance vector analysis. At study ending, the subjects had a total weight loss of 28% of baseline body weight (15% after 6 months). After LASGB, weight loss was mainly due to decreased FM, and TBW, FFM, and body hydration were not significantly reduced. Weight loss was associated with an 82% rise in serum DHEAS already after 6 months while cortisol, cortisol/DHEAS molar ratio, and insulin levels fell by 5.5, 62 and 50%, respectively, after 6, 12 and 24 months (p<0.05).

CONCLUSIONS

LASGB associated with a well balanced low-calorie diet permits a satisfactory 2-yr weight loss, sparing FFM and without body fluid alterations. As the result of a stable weight reduction program weight loss is associated to decrease in cortisol, cortisol/DHEAS molar ratio, and insulin plasma levels with marked rise in DHEAS. Higher cortisol/DHEAS molar ratio values at baseline are also associated to lower weight loss after LASGB, with lower decrease in FM and higher reduction in FFM and body cell mass, in spite of no differences in dietary regimes. Cortisol/DHEAS molar ratio is likely to represent a reliable marker of favourable modifications in body composition.