Medroxyprogesterone acetate enhances monocyte-endothelial interaction under flow conditions by stimulating the expression of cell adhesion molecules

Equilin in conjugated equine estrogen increases monocyte-endothelial adhesion via NF-κB signaling

The adhesion of monocytes to endothelial cells, which is mediated by adhesion molecules, plays a crucial role in the onset of atherosclerosis. Conjugated equine estrogen, which is widely used for estrogen-replacement therapy, contains both estrone sulfate and various nonhuman estrogens, including equilin. To investigate the association between various estrogen types and atherosclerosis risk, we examined their effect on adhesion-molecule expression in human umbilical vein endothelial cells (HUVECs). In estrogen-treated HUVECs, the mRNA and protein expression levels of adhesion molecules were quantified by real-time polymerase chain reaction and enzyme immunoassay. Additionally, a flow-chamber system was used to assess the effects of estrogens on the adherence of U937 monocytoid cells to HUVECs. Equilin, but not 17β-estradiol (E2) or other types of estrogen, significantly increased the mRNA (P < 0.01) and protein (P < 0.05) expression of the adhesion molecules E-selectin and intercellular adhesion molecule-1 as compared with levels in controls. Equilin treatment increased the adherence of U937 monocytoid cells to HUVECs relative to the that in the control (P < 0.05), decreased estrogen receptor (ER)β expression, and increased the expression of proteins involved in nuclear factor kappa-B (NF-κB) activation relative to levels in controls. Furthermore, the accumulation of NF-κB subunit p65 in HUVEC nuclei was promoted by equilin treatment. By contrast, E2 treatment neither increased the number of adhered monocytoid cells to HUVECs nor altered the expression of ERβ or NF-κB-activating proteins. Our findings suggest that in terms of the adhesion of monocytes at the onset of atherosclerosis, E2 may be preferable for estrogen-replacement therapy. Further studies comparing equilin treatment with that of E2 are needed to investigate their differential impacts on atherosclerosis.

Daidzein-rich isoflavone aglycones inhibit cell growth and inflammation in endometriosis

Endometriosis is an estrogen-dependent disease, and isoflavones interact with estrogen receptors. The purposes of this study are to investigate the in vitro and in vivo effects of daidzein-rich isoflavone aglycones (DRIAs), dietary supplements, on cellular proliferation in endometriosis. Stromal cells isolated from ovarian endometrioma (OESCs) and normal endometrium (NESCs) were cultured with DRIAs, i.e., each of the DRIA components (daidzein, genistein, or glycitein), or isoflavone glycosides (IG; DRIA precursors). A mouse model of endometriosis was established by transplanting donor-mouse uterine fragments into recipient mice. Our results showed that DRIAs (0.2-20 μM) inhibited the proliferation of OESCs (P < 0.05 for 0.2 μM; P < 0.01 for 2 and 20 μM) but not of NESCs. However, daidzein, genistein, glycitein, and IG did not inhibit their proliferation. DRIA-induced suppression was reversed by inhibition of the estrogen receptor (ER)β by an antagonist, PHTPP, or by ERβ siRNA (P < 0.05), but not by MPP, an ERα antagonist. In OESCs, DRIAs led to reduced expression of IL-6, IL-8, COX-2, and aromatase, as well as reduced aromatase activity, serum glucocorticoid-regulated kinase levels, and PGE₂ levels (P < 0.05). Western blot and immunofluorescence assays revealed that DRIAs inhibited TNF-α-induced IκB phosphorylation and p65 uptake into the nuclei of OESCs. In the mouse model, a DRIA-containing feed significantly decreased the number, weight, and Ki-67 proliferative activity of endometriosis-like lesions compared to in mice fed with an IG-containing feed and the control feed (P < 0.01). In conclusion, DRIAs inhibit cellular proliferation in endometriosis, thus representing a potential therapeutic option for the management of endometriosis.

Rapamycin inhibits ox-LDL-induced inflammation in human endothelial cells in vitro by inhibiting the mTORC2/PKC/c-Fos pathway

Rapamycin and its derivative possess anti-atherosclerosis activity, but its effects on adhesion molecule expression and macrophage adhesion to endothelial cells during atherosclerosis remain unclear. In this study we explored the effects of rapamycin on ox-LDL-induced adhesion molecule expression and macrophage adhesion to endothelial cells in vitro and the underlying mechanisms. Ox-LDL (6-48 μg/mL) dose-dependently increased the protein levels of two adhesion molecules, intercellular adhesion molecule-1 (ICAM-1) and E-selectin, in human umbilical vein endothelial cells (HUVECs), whereas pretreatment with rapamycin (1-10 μmol/L) dose-dependently inhibited ox-LDL-induced increase in the adhesion molecule expression and macrophage adhesion to endothelial cells. Knockdown of mTOR or rictor, rather than raptor, mimicked the effects of rapamycin. Ox-LDL (100 μg/mL) time-dependently increased PKC phosphorylation in HUVECs, which was abolished by rapamycin or rictor siRNA. Pretreatment with PKC inhibitor staurosporine significantly reduced ox-LDL-stimulated adhesion molecule expression and macrophage adhesion to endothelial cells, whereas pretreatment with PKC activator PMA/TPA attenuated the inhibitory effect of rapamycin on adhesion molecule expression. Ox-LDL (100 μg/mL) time-dependently increased c-Fos levels in HUVECs, and pretreatment with rapamycin or rictor siRNA significantly decreased expression of c-Fos. Knockdown of c-Fos antagonized ox-LDL-induced adhesion molecule expression and macrophage adhesion to endothelial cells. Our results demonstrate that rapamycin reduces ox-LDL-stimulated adhesion molecule expression and macrophage adhesion to endothelial cells by inhibiting mTORC2, but not mTORC1, and mTORC2 acts through the PKC/c-Fos signaling pathway.

Effects of drospirenone on adhesion molecule expression and monocyte adherence in human endothelial cells

OBJECTIVE

A major concern in hormone replacement therapy is the associated increased risk of cardiovascular diseases. A progestogen without the unfavorable effects on cardiovascular disease should be explored. Monocyte adhesion to endothelial cells is an important initial event in atherosclerosis. In this study, the effects of the alternative progestogen drospirenone (DRSP) on monocyte adhesion in human umbilical venous endothelial cells (HUVECs) were examined.

STUDY DESIGN

In HUVECs treated with estrogens and progestogens, including DRSP and medroxyprogesterone acetate (MPA), the expression of the adhesion molecules E-selectin, P-selectin, ICAM-1, and VCAM-1 were examined by real-time PCR and using an enzyme-linked immunosorbent assay. A flow chamber system was used to investigate the effects of DRSP on U937 monocytoid cell adherence to HUVEC monolayers. All experimental data were compared using one-way Analysis of Variance.

RESULTS

Upregulation of adhesion molecule mRNA or protein was not seen in HUVECs treated with DRSP alone or with 17β-estradiol+DRSP. DRSP alone, 17β-estradiol+DRSP or ethinylestradiol+DRSP did not increase the number of adherent monocytoid cells to HUVECs in the flow chamber system. However, MPA significantly enhanced the monocytoid cell adherence (P<0.05).

CONCLUSIONS

DRSP did not increase the expression of adhesion molecules or monocytoid cell adherence to endothelial cells, indicating that DRSP could reduce the risk of atherogenesis caused by MPA. These results suggest that DRSP may be an alternative to MPA in hormone replacement therapy.

Progesterone or progestin as menopausal ovarian hormone therapy: recent physiology-based clinical evidence

PURPOSE OF REVIEW

Provide evidence-based recent data on oral micronized progesterone (OMP) and progestins in menopausal hormonal therapy (MHT).

RECENT FINDINGS

Medroxyprogesterone acetate (MPA) increases breast cancer acting through the glucocorticoid receptor; progestins in MHT increase thrombosis more than oral estrogens; MPA, but not OMP or other progestins, increase monocyte cell endothelium adhesion; MPA and estradiol (E2)/MPA have negative brain effects, whereas E2/progesterone (P4) has neuroregenerative brain effects. The 'window of opportunity' cardiovascular disease hypothesis is not supported by a randomized controlled trial showing that transdermal estradiol with sequential OMP in early menopause does not prevent increased carotid intimal media thickness; P4 in the cardiac electrical system opposes E2 effects and prevents sudden death/long QT syndrome; transdermal estradiol/OMP does not increase venous thromboembolism in observational data. P4 decreases breast cell proliferation and improves prognosis through P4 receptor alteration of estrogen receptor α genetic effects; OMP with conjugated equine estrogen (CEE)/estrogen (E)/E2 does not increase breast cancer in two prospective cohorts, one population-based. Endometrial cancer is increased in MHT of CEE/E/E2+cyclic OMP at 200 mg/day.

SUMMARY

New data show CEE/E/E2+MPA/P mechanisms for negative breast cancer, venous thromboembolism, cardiovascular system, and brain effects. OMP/P4 counterbalances CEE/E/E2-related negative effects on breast cancer and long QT syndrome. OMP effectively treats vasomotor symptoms and sleep disturbances, and could safely be used alone for symptomatic menopause.