Venous endothelial function in postmenopausal women who are receiving long-term estrogen and progestagen therapy

Insulin Resistance and Pellino-1 Mediated Decrease in the Activities of Vasodilator Signaling Contributes to Sunitinib-Induced Hypertension

Antiangiogenic tyrosine kinases inhibitors induce hypertension, which may increase the incidents of cardiovascular complications and limit their use. However, the mechanisms by which usage of TKIs results in hypertension have not been fully understood. Here, we report the potential mechanisms of how sunitinib, a widely used TKI, induces hypertension. Male SD rats were randomly divided into control group and sunitinib-administrated group. We show that sunitinib administration for seven days caused a significant increase in artery blood pressure, along with glycerolipid metabolism abnormalities including decreased food intake and low body weight, hypoglycemia, hyperinsulinemia. Sunitinib administration also resulted in a significant increase in the levels of insulin autoantibody (IAA), cyclic adenosine monophosphate and free fatty acid in serum; whereas, sunitinib administration had no effects on serum glucagon levels. Sunitinib led to the decreased insulin sensitivity as determined by insulin tolerance test (ITT) and glucose tolerance test (GTT), reflecting insulin resistance occurred in sunitinib-treated rats. The results obtained from wire myograph assay in the mesenteric arteries show that endothelium-dependent relaxation, but not endothelium-independent relaxation, was impaired by sunitinib. Furthermore, western blot analysis revealed that the expressions levels of phosphorylated IRS-1, Pellino-1, AKT and eNOS were significantly attenuated by sunitinib in rat mesenteric artery tissues and in the sunitinib-treated primary cultured mesenteric artery endothelial cells. The levels of serum and endothelium-derived nitric oxide were also significantly decreased by sunitinib. Moreover, sunitinib-induced decrease in the expression levels of phosphorylated AKT and eNOS was further reduced by knocking down of Pellino-1 in MAECs. Our results suggest that sunitinib causes vascular dysfunction and hypertension, which are associated with insulin resistance- and Pellino-1-mediated inhibition of AKT/eNOS/NO signaling. Our results may provide a rational for preventing and/or treating sunitinib-induced endothelial dysfunction and hypertension.

Increase and Redistribution of Sex Hormone Receptors in Premenopausal Women Are Associated with Varicose Vein Remodelling

In chronic venous insufficiency of the lower limbs, data show that the clinical manifestation is varicose veins (VVs), and VV epidemiology suggests that sex hormones directly influence disease development through intracellular receptors. This study aimed to determine the presence and localization of oestrogen receptors (ERs), progesterone receptors (PRs), and androgen receptors (ARs) in both healthy and VV wall cells and their relationship with gender. In this study, samples from patients without a history of venous disease (CV) (n = 18) and with VV (n = 40) were used. The samples were divided by gender: CV women (CVw) = 6, CV men (CVm) = 12, VV women (VVw) = 25, and VV men (VVm) = 15. RT-qPCR and immunohistochemical techniques were performed, and increased ER and PR protein expression was found in VVw in all tunica layers. ARs were localized to the adventitial layer in the CV and were found in the neointima in VVs. mRNA expression was increased for ER and PR in VVw. AR gene expression was significantly decreased in VVm. The increase in the number of these receptors and their redistribution through the wall reinforces the role of sex hormones in varicose vein development.

Vascular actions of estrogens: functional implications

The impact of estrogen exposure in preventing or treating cardiovascular disease is controversial. But it is clear that estrogen has important effects on vascular physiology and pathophysiology, with potential therapeutic implications. Therefore, the goal of this review is to summarize, using an integrated approach, current knowledge of the vascular effects of estrogen, both in humans and in experimental animals. Aspects of estrogen synthesis and receptors, as well as general mechanisms of estrogenic action are reviewed with an emphasis on issues particularly relevant to the vascular system. Recent understanding of the impact of estrogen on mitochondrial function suggests that the longer lifespan of women compared with men may depend in part on the ability of estrogen to decrease production of reactive oxygen species in mitochondria. Mechanisms by which estrogen increases endothelial vasodilator function, promotes angiogenesis, and modulates autonomic function are summarized. Key aspects of the relevant pathophysiology of inflammation, atherosclerosis, stroke, migraine, and thrombosis are reviewed concerning current knowledge of estrogenic effects. A number of emerging concepts are addressed throughout. These include the importance of estrogenic formulation and route of administration and the impact of genetic polymorphisms, either in estrogen receptors or in enzymes responsible for estrogen metabolism, on responsiveness to hormone treatment. The importance of local metabolism of estrogenic precursors and the impact of timing for initiation of treatment and its duration are also considered. Although consensus opinions are emphasized, controversial views are presented to stimulate future research.

Vasodilatory action of loop diuretics: a plethysmography study of endothelial function in forearm arteries and dorsal hand veins in hypertensive patients and controls

INTRODUCTION

Intravenous administration of loop diuretics induces venodilation before the diuretic response. We investigated whether furosemide and torasemide exert a dilatory effect on arteries and veins mediated by endothelial release of nitric oxide.

METHODS

We performed intermittent venous occlusion plethysmography to study forearm blood flow and dorsal hand-vein distension in response to furosemide and torasemide infusion in hypertensive patients and healthy controls.

RESULTS

Furosemide increased venodilation from 0.56 +/- 0.09 to 0.88 +/- 0.06 (P=0.000) in control subjects and from 0.49 +/- 0.10 to 0.75 +/- 0.12 (P=0.000) in hypertensive patients. Torasemide increased venodilation from 0.46 +/- 0.06 to 0.70 +/- 0.11 (P=0.007) in control subjects and from 0.48 +/- 0.09 to 0.67 +/- 0.12 (P = 0.03) in hypertensive patients. Co-infusion of the Nitric Oxide Synthase Inhibitor (L-NMMA)-blocked this venodilation, and the action was reversed with L-arginine. There were no significant changes in the arterial bed.

CONCLUSIONS

Furosemide and torasemide induce a similar dose-response curve venodilation, but they have no effect on the arterial bed. Hypertensive patients show a smaller venous endothelium-dependent response than healthy controls. The venodilation induced by both diuretics requires release of nitric oxide.

Menopause, estrogens, and endothelial dysfunction: current concepts

Menopause is defined as the permanent cessation of menses. Cardiovascular disease is the leading cause of death among postmenopausal women in developed countries. The disparity between the incidence of cardiovascular disease among women in pre- and postmenopause has been ascribed to the actions of endogenous estrogen on the cardiovascular system and, particularly, on the vascular endothelium. The endothelium plays an important role in cardiovascular homeostasis, either through the vascular tonus and its regulation, or through coagulation and the inflammatory response. Endothelial dysfunction is implicated in the genesis of atherosclerosis and other chronic disorders, such as diabetes mellitus and hypertension. The pharmacological use of estrogen exerts influence on the circulating levels of markers of vascular tonus, and inflammation, as well as prothrombotic, and fibrinolytic markers, but the impact of these changes on the atherosclerotic disease is still uncertain.

Venous endothelial function in postmenopausal women after six months of tibolone therapy

STUDY OBJECTIVE

To test venous endothelial function in long-term climateric therapy with tibolone.

DESIGN

Measurement of dorsal hand-vein diameter by venous occlusion plethysmography during infusion of norepinephrine (NE), bradykinin (BK), NG-monomethyl L-arginine (L-NMMA) and sodium nitroprusside (SNP).

SETTING

Plethysmography and Menopause Units. University Hospital Valdecilla. Santander. Spain.

PATIENTS

Eleven postmenopausal women having continuous treatment with oral tibolone (2.5 mg/day) for 6 months.

INTERVENTIONS

Three plethysmography studies were made: at baseline, and at three and six months of treatment.

MAIN OUTCOME MEASURES

Dorsal hand-vein diameter measured by venous occlusion plethysmography during infusion of NE, BK, L-NMMA and SNP.

RESULTS

(a) Baseline study: maximum dilation with BK was 54.2+/-10.2%. (b) Three-month study: BK dilation of 71.5+/-11.9%, with a significant increase of 17.3% (P=0.019) compared with baseline. (c) Six-month study: BK dilation of 77.5+/-11.9%, with a significant increase 23.3% (P=0.002) compared with baseline. Maximal vasodilation was reached with SNP in the three studies and L-NMMA infusion has a similar vasoconstrictor response in the three studies.

CONCLUSIONS

Long-term climateric therapy with tibolone improves vein endothelium-dependent vasodilation suggesting a positive impact of this drug on endothelial function.