Transdermal estrogens do not appear to modify the extent of lesional areas of aortic atherosclerosis in oophorectomized rabbits on a cholesterol-rich diet

Anti-inflammatory effects of a Chinese herbal medicine in atherosclerosis via estrogen receptor β mediating nitric oxide production and NF-κB suppression in endothelial cells

Bu-Shen-Ning-Xin Decoction (BSNXD) administration has alleviated the early pathologic damage of atherosclerosis by inhibiting the adhesion molecule expression and upregulating the estrogen receptor (ER) β expression in endothelial cells, and increasing the serum nitric oxide (NO) level without any effect on serum lipid status, endometrium and fat deposition in liver in ovariectomized rabbits. The BSNXD-derived serum increases ER β expression in the human umbilical vein endothelial cells (HUVECs), and decreases malondialdehyde (MDA) production, and upregulates eNOS expression then increases NO synthesis through ERβ-dependent pathway. NO not only suppresses the LPS-induced NF-κB transcription in HUVECs, but also decreases apoptosis of endothelial cells. The BSNXD-derived serum decreases monocyte chemoattractant protein-1 production, and suppresses cell adhesion molecules (ICAM-1, VCAM-1 and E-selectin) expression in HUVECs injured by oxidized low-density lipoproteins (ox-LDL), and these effects can be abolished by ERβ antagonist (R,RTHC) and NO synthase inhibitor (L-NAME). The BSNXD-derived serum-treated HUVECs supernatant reduces CCR2, LFA-1 and VLA-4 expression in monocytes cell line U937 cells, which in turn inhibits adherence of U937 to injured endothelial cells. NO synthesis increases, and MDA production decreases through ERβ-mediated pathway that suppresses apoptosis and NF-κB activity in endothelial cells that downregulates adhesion molecules expression on endothelial cells via ERβ/NO/NF-κB pathway, and in turn leukocyte adhesion, which suggests BSNXD potential value in prophylaxis atherosclerosis.

Protective effects of dehydroepiandrosterone on atherosclerosis in ovariectomized rabbits via alleviating inflammatory injury in endothelial cells

OBJECTIVE

The risk for atherosclerosis is increased in postmenopausal women. Dehydroepiandrosterone (DHEA) is postulated to have anti-atherogenic properties, but the mechanism remains unclear. The aim of this study was to elucidate the protective effect of DHEA on atherosclerosis in ovariectomized rabbits.

METHODS

The lipid status and atherosclerotic lesions were examined in vivo in ovariectomized rabbits. The effects of DHEA on expression of inflammatory molecules were evaluated in vitro, such as nitric oxide (NO), malondialdehyde (MDA), monocyte chemoattractant protein-1 (MCP-1), adhesion molecules (ICAM-1, VCAM-1 and E-selectin) in the human umbilical vein endothelial cells (HUVECs) injured by oxidized low-density lipoproteins (ox-LDL). The adhesion of the monocytic U937 cells to HUVECs was treated with supernatants of ox-LDL treated HUVECs with or without DHEA, and then the expressions of CCR2, LFA-1, VLA-4 were analyzed in U937 cells. The HUVECs with or without LPS treatment were then treated with DHEA, and NF-κB activity was measured by luciferase activity.

RESULTS

DHEA administration alleviates efficiently the early pathologic damage of atherosclerosis, increases the serum NO level, and up-regulates the endothelial cell estrogen receptor (ER) expression of ovariectomized rabbits. DHEA in vitro significantly promotes NO synthesis, suppresses MDA and MCP-1 secretion of endothelial cells, and decreases ICAM-1, VCAM-1 and E-selectin expression in HUVECs; neither selective ERα antagonist (methyl-piperidino-pyrazole, MPP) nor ERβ antagonist (R,R-tetrahydrochrysene, R,RTHC) can abolish these effects. Furthermore, DHEA reduces CCR2, LFA-1 and VLA-4 expression in U937 cells, which in turn inhibits the adherence of monocytes to the injured endothelial cells. DHEA significantly decreased the LPS-induced NF-κB transcription.

CONCLUSIONS

Our findings suggest that DHEA can alleviate inflammation in endothelial cells. The effects of DHEA on endothelial cells are independent of ERα or ERβ pathway, but at least in part, through suppression of NF-κB activity, which protects from atherosclerosis triggered by monocyte adherence.

Hormone replacement therapy and the cardiovascular system lessons learned and unanswered questions

Cardiovascular disease is the leading cause of death among women in the U.S., exceeding breast cancer mortality in women of all ages. Women present with cardiovascular disease a decade after men, and this has been attributed to the protective effect of female ovarian sex hormones that is lost after menopause. Animal and observational studies have shown beneficial effects of hormone therapy when it is initiated early in the perimenopausal period or before the development of significant atherosclerosis. However, randomized, placebo-controlled trials in older women have not shown any benefit in either primary prevention or secondary prevention of cardiovascular events, with a concerning trend toward harm. This review outlines the lessons learned from the basic science, animal, observational, and randomized trials, and then summarizes yet-unanswered questions of hormone therapy and cardiovascular risk.

Vascular reactivity and atheromatous plaques in post-menopausal women on tibolone treatment

BACKGROUND

Arteriosclerosis is the main cause of ischaemic ictus. The middle cerebral and anterior cerebral arteries, which irrigate over 70% of the entire cerebral tissue, spring from the internal carotid. Additionally, it is in the extracraneal vessels that embolism, thrombosis and stenosis originate more frequently.

AIM

To evaluate the variations in blood flow (pulsatility index: PI) and to assess the evolution of atherogenic lesions (thickening of the vascular intima and the presence of atheromatous plaques) in the internal carotid artery after tibolone therapy.

SUBJECTS AND METHODS

A total of 116 healthy menopausal women were included in this open, prospective and comparative study. Of them, 101 subjects completed the 48 weeks follow-up. Subjects were allocated in two groups: group T (n = 55) received 2.5mg/day of tibolone daily and group C (n = 61) was a free-treatment control group. To evaluate both resistance to blood flow and the existence and evolution of atheromatous plaques in the internal carotid, an ultrasonograph with a pulsed Doppler was used. The PI was used as the parameter of vascular tone. To study atherosclerotic lesions in the internal carotid artery, we used morphological criteria. Measurements were done before entering in the study, and at 12, 24, 36 and 48 weeks of treatment.

RESULTS

After tibolone treatment the PI in the internal carotid artery was observed markedly diminished. Moreover, tibolone reduces both the thickness and length of atheromatous plaque and the degree of vascular stenosis.

CONCLUSION

tibolone administration reduced the carotid atheromatous plaque in thickness and length and improved cerebral perfusion.

Effects of estradiol, cyproterone acetate, tibolone and raloxifene on uterus and aorta atherosclerosis in oophorectomized cholesterol-fed rabbits

BACKGROUND

Different hormonal replacement regimens are used for treating climacteric complaints; however, not all of them have the same clinical profile. Cardiovascular disease (CVD) is a major health problem and tibolone, raloxifene, estradiol (alone or with cyproterone acetate) have been added to cholesterol-fed rabbits to study atherosclerosis.

METHODS

A total of 48 cholesterol-fed New Zealand white rabbits were studied for 4 months. Forty rabbits underwent bilateral ovariectomy and the other eight were sham operated (group S). The ovariectomized rabbits were allocated to five groups of eight animals each receiving tibolone (Group T, 6 mg/day), raloxifene (R, 35 mg/day), estradiol valerate (E, 3 mg/day), estradiol valerate plus cyproterone acetate (EC, 3+0.5 mg/day, respectively), and no treatment for the control group (C). The sham group received no treatment too.

RESULTS

After 4 months the percentage of the extent of atherosclerosis in the aorta was 30.4% in C group, 24.5% in S group, 10.2% in T group, 30.3% in R group, 17.9% in E group and 28.1% in EC group (P<0.05 T vs. C, R, EC). The aortic cholesterol content compared with aortic weight was 8.55 microg/mg in C group, 11.97 microg/mg in S group, 1.86 microg/mg in T group, 3.82 microg/mg in R group, 2.86 microg/mg in E group and 5.24 microg/mg in EC group (P<0.05 T vs. EC, C, S; R vs. C, S; E vs. C, S). Uterine weights in grams were: 1.89 (C group), 2.24 (S), 7.38 (T), 1.94 (R), 9.92 (E), and 5.94 (EC); P<0.05 (C, S, R, vs. T, E, EC; T vs. E; EC vs. T, E).

CONCLUSION

Our study showed a decrease in the extent of aortic atherosclerosis in oophorectomized cholesterol-fed rabbits treated with tibolone or estradiol, and a decrease in aortic cholesterol content in rabbits treated with tibolone, raloxifene and estradiol. However, rabbits treated with tibolone showed an increased uterine weight, which is contrary to that observed in humans.

Isoflavonoid compounds from red clover (Trifolium pratense) protect from inflammation and immune suppression induced by UV radiation

Isoflavones derived from many edible plants have been reported to possess significant antioxidant, estrogenic and tyrosine kinase inhibitory activity. Genistein has been found previously to provide protection from oxidative damage induced by UV radiation both in vitro and following dietary administration. We have therefore examined the potential of a number of isoflavones from red clover (Trifolium pratense) and some metabolically related compounds to offer protection from UV irradiation in hairless mice by topical application after UV exposure. We show that whereas the primary isoflavones, daidzein, biochanin A and formononetin, were inactive, 20 microM lotions of genistein and the metabolites equol, isoequol and the related derivative dehydroequol had powerful potential to reduce the inflammatory edema reaction and the suppression of contact hypersensitivity induced by moderate doses of solar-simulated UV radiation. For equol the protection was concentration dependent and 5 microM equol markedly reduced the UV-induced inflammation but abrogated the UV-induced immunosuppression. Equol protected similarly from immunosuppression induced by the putative epidermal mediator, cis-urocanic acid (UCA), indicating a potential mechanism of action involving inactivation of this UV-photoproduct. Since immunosuppression induced by both UV radiation and by cis-UCA appears to be an oxidant-dependent response our observations support the actions of these topically applied isoflavones and their metabolites as antioxidants. They also indicate that lotions containing equol, unlike topical UV sunscreens, more readily protect the immune system from photosuppression than from the inflammation of the sunburn reaction, even when applied after exposure, and thus such compounds may have a future role as sun-protective cosmetic ingredients.

Do we need clinical trials to test the ability of transdermal HRT to prevent coronary heart disease?

Postmenopausal hormone replacement therapy (HRT) with oral oestrogen was predicted to reduce coronary heart disease (CHD) risk by 50%. Randomized controlled trials show no such benefit, however, pointing instead to an initial increase in CHD events. Although the cardiovascular effects of transdermal HRT are largely unknown, improvements in arterial function are maintained when oestrogen is administered transdermally. Transdermal HRT also avoids the increased plasma levels of C-reactive protein (CRP) that are seen with oral HRT. However, the clinical significance of this general reduction in hepatic over-synthesis of plasma proteins is difficult to assess. Nevertheless, the available evidence on transdermal HRT appears to justify a formal clinical trial.