Canine vascular tissues are targets for androgens, estrogens, progestins, and glucocorticoids

Abdominal imaging in precocious puberty in girls: can imaging determine onset of puberty?

Precocious puberty in girls is defined by the appearance of secondary sex characteristics before the age of 8 years. Precocious puberty is either peripheral or central. In most cases, the cause of central precocious puberty is unknown. Rapidly progressive forms of central precocious puberty may benefit from puberty suppression to prevent compromised final height and psychosocial problems related to the physical changes. Idiopathic central precocious puberty in girls can be a challenging diagnosis. Clinical examination, evaluation of growth charts, bone age, and hormonal tests are part of the workup. The role of pelvic ultrasound to evaluate pubertal features of the internal genitalia in this context is controversial. In this paper, we have reviewed the literature to find the scientific bases for several proposed ultrasound parameters and cutoff values for the determination of onset of puberty in girls with suspected central precocious puberty. There are no reliable cutoffs for the measurements of uterus and ovaries for the diagnosis of central precocious puberty and there is overlap in the appearance of the organs in both prepubertal and pubertal girls. The interpretation of the findings on pelvic ultrasound must be done with caution and always in close communication with the referring clinicians.

Progesterone Inhibitory Role on Gastrointestinal Motility

Progesterone is a steroidal hormone that is produced from the corpus luteum of the ovaries and from the placenta. The main function of progesterone is to promote the secretory differentiation in the endometrium of the uterus and to maintain pregnancy by inhibiting uterine contractions throughout pregnancy. Progesterone performs its actions by activating the classical progesterone nuclear receptors that affect gene transcription and by the non-classical activation of cell surface membrane receptors that accounts for the rapid actions of progesterone. Besides the reproductive roles of progesterone, it exerts functions in many tissues and systems such as the nervous system, the bone, the vascular system, and the gastrointestinal (GI) tract. This review will summarize the recent literature that investigated the role of progesterone in GI tract motility. Most literature indicates that progesterone exerts an inhibitory role on gut smooth muscle cells in part by elevating nitric oxide synthesis, which induces relaxation in smooth muscle. Moreover, progesterone inhibits the signaling pathways that lead to contraction such as Rho kinase inhibition. These data serve as a quick resource for the future directions of progesterone research that could lead to better understanding and more effective treatment of gender-related GI tract motility disorders.

Activated androgen receptor accelerates angiogenesis in cutaneous neurofibroma by regulating VEGFA transcription

Accumulating evidence has demonstrated the significant progression of cutaneous neurofibroma (cNF) without necrosis during puberty. However, the molecular events involved in this process remain unclear. The alteration of the steroid hormone levels during puberty has led to the investigation of the expression levels of the androgen receptor (AR). A positive correlation between AR expression and microvessel density has been reported in human cNF tissues in combination with enhanced endothelial cell tube formation in vitro. In addition, activated AR signaling can promote neurofibroma cell growth in vivo and in vitro and tube formation in vitro. In the present study, AR was shown to bind directly to the promoter of vascular endothelial growth factor A (VEGFA), a key factor involved in angiogenesis, and to sequentially induce its expression. Furthermore, the AR inhibitor, MDV3100, downregulated VEGFA expression and abolished endothelial cell recruitment and tube formation. Taken collectively, the findings of this study revealed that AR signaling enhanced tumor growth and angiogenesis in cNF by regulating VEGFA transcription. However, whether AR can be regarded a therapeutic target for cNF requires further investigation.

Validation of an Accurate and Noninvasive Tool to Exclude Female Precocious Puberty: Pelvic Ultrasound With Uterine Artery Pulsatility Index

OBJECTIVE. The purpose of this study is to validate the accuracy of pelvic ultrasound (US) with the evaluation of uterine artery pulsatility index (PI) to exclude female precocious puberty. MATERIALS AND METHODS. Tanner breast development score, luteinizing hormone (LH) peak after gonadotropin-releasing hormone (GnRH) stimulation, and uterine and ovarian volumes and diameters were assessed with pelvic US in 495 girls at a single institution. The study population was divided as follows: prepubertal (n = 207), pubertal with physiologic activation of the hypothalamic-pituitary-ovarian axis (n = 176), and central precocious puberty (CPP; n = 112). PI was measured with spectral Doppler US at the ascending branches of the right uterine artery (50-Hz filter; time gain compensation, 73; pulse repetition frequency, 6.6). ROC analyses and t tests were performed. RESULTS. The mean (± SD) PI values in the prepubertal, pubertal, and CPP groups were 6.3 ± 1.4, 3.4 ± 1.1, and 4.1 ± 1.5, respectively (p < 0.001). The best PI cutoff value to distinguish pubertal from prepubertal girls was 4.6 (sensitivity, 83%; specificity, 94%; positive predictive value, 95%; negative predictive value, 80%; accuracy, 87%). ROC AUC values for LH peak (cutoff value, 5 mU/mL) and for spectral Doppler US PI plus longitudinal uterine diameter (i.e., the combination of a PI of 4.6 with a longitudinal uterine diameter of 35 mm) were 0.9272 and 0.9439, respectively (p = 0.7925). The negative predictive values for LH peak and for PI plus longitudinal uterine diameter were 89% and 88%, respectively. CONCLUSION. A PI greater than 4.6 at spectral Doppler US combined with a longitudinal uterine diameter less than 35 mm allows noninvasive exclusion of female precocious puberty with comparable accuracy and lower costs compared to examination of LH peak after GnRH stimulation. Therefore, PI plus longitudinal uterine diameter might be used as a noninvasive first-line test to exclude precocious puberty and thereby avoid further investigations.

The role of androgen receptors in atherosclerosis

Male disadvantage in cardiovascular health is well recognised. However, the influence of androgens on atherosclerosis, one of the major causes of many life-threatening cardiovascular events, is not well understood. With the dramatic increase in clinical prescription of testosterone in the past decade, concerns about the cardiovascular side-effects of androgen supplementation or androgen deprivation therapy are increasing. Potential atheroprotective effects of testosterone could be secondary to (aromatase-mediated) conversion into oestradiol or, alternatively, to direct activation of androgen receptors (AR). Recent development of animal models with cell-specific AR knockout has indicated a complex role for androgen action in atherosclerosis. Most studies suggest androgens are atheroprotective but the precise role of AR remains unclear. Increased use of AR knockout models should clarify the role of AR in atherogenesis and, thus, lead to exploitation of this pathway as a therapeutic target.

Cardiac parameters during the estrous cycle of canine bitches

ABSTRACT: The cardiovascular parameters of canine bitches were assessed during the estrous cycle. A total of eleven mongrel female dogs were enrolled in a longitudinal prospective investigation. Six animals were bred during the study and were assigned into group I, in which evaluations were performed during proestrus, estrus, gestational diestrus and anestrus. The five remaining bitches were not bred and underwent evaluations during proestrus, estrus, nongestational diestrus and anestrus. The holter data showed a gradual increase in the minimum and mean heart rate along pregnancy, as well as a reduction during anestrus, which differed significantly among the distinct periods. The values for maximal heart rate documented during pregnancy were significantly lower than those recorded during anestrus, and a variation in the heart rate circadian rhythm was also found, as demonstrated by decreases at night and rises during the day. Cardiac rhythm had a similar performance in both pregnancy and anestrus. Likewise, the blood pressure, electrocardiography, and echocardiography data did not vary during the estrous cycle. The results support the role played by the autonomic nervous system during these two distinct periods in order to attain a heart rate that provides the blood needed by the female’s body during the various stages of the reproductive cycle. Further studies are needed to better clarify the cardiovascular compensatory neuroendocrine events that accompany gestation in this species.

Uterine volume and endometrial thickness in the early follicular phase in patients with polycystic ovary syndrome

OBJECTIVE

We aimed to evaluate uterine volume and endometrial thickness during the early follicular phase in patients with polycystic ovary syndrome (PCOS) and healthy controls.

METHODS

We studied 1,016 PCOS patients and 182 healthy controls. The anthropometric, endocrine, and metabolic characteristics of PCOS were determined. Uterine volume and endometrial thickness were also recorded.

RESULTS

Uterine volume progressively increased with age both in PCOS patients and controls. Patients with PCOS and body mass index (BMI) ≥25 kg/m2 had greater uterine volumes than PCOS patients with BMI <25 kg/m2 (P<.001). Patients with the classic PCOS phenotypes (i.e., with oligo-ovulation and/or anovulation [ANOV] and hyperandrogenemia [HA] with or without polycystic ovaries [PCO]) had smaller uterine volume than PCOS patients with the additional phenotypes introduced by the Rotterdam criteria (i.e., with PCO and either ANOV or HA; P = .033) and controls (P = .045).

CONCLUSION

Uterine volume increases progressively with age and obesity in PCOS patients. The smaller uterine volumes and endometrial thicknesses in the classic PCOS phenotypes might be attributed to the more severe HA of these patients.

Primary epiphyseal arteriopathy in a mouse model of steroid-induced osteonecrosis

Patients undergoing glucocorticoid therapy for a variety of disorders, including autoimmune diseases and hematological malignancies, are at risk of developing osteonecrosis. Despite extensive research in both patients and animal models, the underlying pathogenesis remains unclear. Proposed inciting mechanisms include intravascular thrombotic occlusion, marrow fat hypertrophy, osteocyte and/or endothelial cell apoptosis, hypercoagulability, and vasoconstriction of specific arteries and arterioles supplying bone. Our laboratory has developed a model of steroid-induced osteonecrosis in BALBcJ mice which reflects clinically relevant exposures to glucocorticoids in which treated mice develop osteonecrosis of the distal femoral epiphysis when administered 4 to 8 mg/L dexamethasone in drinking water for 6 weeks. We identified lesions in arterioles supplying this area, with the mildest occurring in knees without any evidence of osteonecrosis. However, arteriopathy was more common among mice that did versus did not develop osteonecrosis (P < 0.0001); in mice with osteonecrosis, the associated vessels showed transmural necrosis and thickening of the vessel wall progressing to the point of luminal obstruction. In the most severe cases of osteonecrosis, end-stage lesions consisted of fully occluded vessels with marrow and bone necrosis involving the entire epiphysis. We propose that a primary arteriopathy is the initiating event in the genesis of steroid-induced osteonecrosis and provides a basis for future investigation of this disease process.

NAD(P)H:quinone oxidoreductase 1 is induced by progesterone in cardiomyocytes

NAD(P)H: quinone oxidoreductase 1 (NQO1) is a ubiquitous flavoenzyme that catalyzes two-electron reduction of various quinones by utilizing NAD(P)H as an electron donor. Our previous study found that progesterone (PG) can protect cardiomyocytes from apoptosis induced by doxorubicin (Dox). Microarray analyses of genes induced by PG had led to the discovery of induction of NQO1 mRNA. We report here that PG induces NQO1 protein and its activity in a dose-dependent manner. Whereas NQO1 is well known as a target gene of Nrf2 transcription factor due to the presence of antioxidant response element (ARE) in the promoter, PG did not activate the ARE, suggesting Nrf2-independent induction of NQO1. To address the role of NQO1 induction in PG-induced cytoprotection, we tested the effect of NQO1 inducer β-naphthoflavone and inhibitor dicoumarol. Induction of NQO1 by β-naphthoflavone decreased Dox-induced apoptosis and potentiated the protective effect of PG as measured by caspase-3 activity. PG-induced NQO1 activity was inhibited with dicoumarol, which did not affect PG-induced cytoprotection. Dicoumarol treatment alone potentiated Dox-induced caspase-3 activity. These data suggest that while NQO1 plays a role in PG-induced cytoprotection, there are additional components contributing to PG-induced cytoprotection.

Effects of androgens on cardiovascular remodeling

Androgens, the male sex hormones, exert various biological effects on many target organs through the transcriptional effects of the nuclear androgen receptor (AR). ARs are expressed not only in classical target organs, such as the brain, genital organs, bone, and skeletal muscles, but also in the cardiovascular system. Because the female sex hormones estrogens are well-known to protect against cardiovascular disease, sex has been considered to have a significant clinical impact on cardiovascular mortality. However, the influence of androgens on the cardiovascular system has not been fully elucidated. To clarify this issue, we analyzed the effects of administration of angiotensin II and doxorubicin, an anticancer agent, in a loading model in male wild-type and AR-deficient mice. In this review, we focus on the actions of androgens as potential targets for the prevention of cardiovascular diseases in males.

Relationship between testosterone deficiency and cardiovascular risk and mortality in adult men

Classic male hypogonadism is associated with known adverse effects including decreased libido, erectile dysfunction, osteoporosis, and changes in body composition. Recently, we have come to appreciate that reduction in serum testosterone (T) levels resulting from aging or chronic disease or androgen deprivation therapy (ADT) have consequences similar to those seen in classic male hypogonadism which include increased fat mass, decreased lean body mass, decreased muscle strength, and sexual dysfunction. These data suggest that low T levels may represent a newly recognized cardiometabolic risk factor. Therefore, we carried out a careful review of the literature, focusing on major turning points of research and studies which gave more important and controversial contribution to the cardiovascular role of T. Observational studies and clinical trials investigating the relationship between T levels and cardiovascular disease and mortality were identified byMedline search. The results were synthesized, tabulated, and interpreted. The aim of this review is to discuss the association between low T levels and adverse metabolic profile such as insulin resistance, metabolic syndrome, and diabetes. We will also investigate the potential mechanisms by which male hypogonadism, especially age related or induced by ADT, may increase cardio-metabolic risk. Finally we will detail the emerging relationship between low T and mortality in men addressing also the reverse hypothesis that low T has a protective role by turning off T-dependent functions.

Nitrate patch prevents steroid-related bone necrosis

Avascular necrosis of the femoral head is a common complication with disabling effect for young patients after high-dose corticosteroid treatment. We could show that steroids have a vasoconstrictive effect on lateral epiphyseal arteries of the femoral head which could lead to ischemia and subsequent necrosis. In this study we investigated the preventive effect of a nitrate patch on steroid-related bone necrosis in a rabbit model. New Zealand White rabbits (male; 3-4.5 kg bodyweight) were injected with 20 mg/kg bodyweight methylprednisolone (GC group; n = 6). Control animals (n = 6) were treated with phosphate-buffered saline. A third group (GC + N; n = 6) additionally received a nitrate patch (0.675 mg/day). Four weeks after i.m. methylprednisolone injection the animals were sacrificed. For histology and immunohistochemistry, tissue samples were fixed in 3% paraformaldehyde, embedded in paraffin, sectioned, dewaxed, and stained with Ladewig. For quantification of empty lacunae, a histologic sign of FHN, histomorphometry was performed. Histomorphometry revealed a significant increase of empty lacunae in glucocorticoid-treated animals compared to controls and GC + N-treated animals. No significant difference in empty lacunae count was detected between the GC + N group and controls. HE staining revealed the different osteocyte amount in the GC versus GC and nitrate patch-treated groups. This study demonstrates an increased number of empty osteocyte lacunae representing a pathologic feature of osteonecrosis, in the GC group. Less empty lacunae were counted in the GC animals after additional treatment with a nitrate patch. This finding suggests that nitrate co-treatment has the potential to prevent steroid-associated FHN.

Estrogen after ischemic stroke: clinical basis and design of the Women's Estrogen for Stroke Trial

BACKGROUND AND PURPOSE

Observational studies have found that women who take estrogen after menopause are less likely to have a stroke than women who do not take estrogen. Although these findings indicate that estrogen may prevent stroke, an alternative explanation for the improved outcome of estrogen users is that they are healthier before starting therapy than nonusers. To test the therapeutic effect of estrogen with research methods that avoid this selection bias, we designed a randomized controlled trial.

TRIAL DESIGN

The Women's Estrogen For Stroke Trial (WEST) is a double-blind, randomized trial with a primary goal of determining whether 1 mg 17beta-estradiol daily, when compared with placebo, reduces the risk of recurrent stroke or death among postmenopausal women who have experienced a transient ischemic attack or nondisabling ischemic stroke. Exclusion criteria include use of estrogen at the time of stroke, breast or uterine cancer, inability to speak English, and estimated survival less than 5 years. Once randomized, women remain under the care of their personal physicians for management of stroke risk factors. For early detection of endometrial hyperplasia and cancer, asymptomatic women receive medroxyprogesterone yearly (5 mg for 12 days) and vaginal ultrasonography or biopsy at the end of the trial. Unscheduled uterine bleeding is evaluated with biopsy. A total of 652 women are sought at 20 hospitals in Connecticut and one in Massachusetts.

CONCLUSIONS

The WEST promises to provide critical guidance to women and their physicians regarding the effectiveness of estrogen in secondary stroke prevention.

Effects of hormone replacement therapy on serum lipids and phospholipids in postmenopausal women

Hormone replacement therapy (HRT) has been shown to reduce the risk of cardiovascular disease and the beneficial effects may be mediated in part by favourable changes in plasma lipid levels. Evidence exists concerning the effect of combined oestrogen and progestogen on lipids, nevertheless no such evidence can be found on the phospholipid profile, which is important the lipid metabolic pathways. In the present study, involving the serum lipids and lipoproteins, we observed an increase in the concentration of total cholesterol (P < 0.001), HDL-C (P < 0.001), HDL-C (P < 0.001), 2 HDL-C (P < 0.001) and a decrease in the ratio LDL-C/ 3 HDL-C (P < 0.001) in the subjects of Group B (oestrogen plus progestogens) compared with controls (baseline). Also, we found an increased in triglycerides (P < 0.01) and ApoA-1 (P < 0.01) concentrations in the subjects of Group A (oestrogen alone) compared with controls (baseline). With regard to the phospholipids, the main changes observed in their concentrations were: an increase in phosphatidyl choline (P < 0.001) and a decrease in phosphatidyl serine (P < 0.01) for both groups compared with controls. Also, a decrease in phosphatidylinositol (P < 0.01) in Group B compared with controls (baseline). The significance of these results are discussed.

Androgen-androgen receptor system protects against angiotensin II-induced vascular remodeling

Age-related andropause promotes cardiovascular disease in males. Although we had previously reported that the androgen-androgen receptor (AR) system plays important roles in cardiac growth and remodeling, the system's involvement in vascular remodeling remains unclear. To clarify this role, 25-wk-old male AR knockout (ARKO) mice and littermate male wild-type (WT) mice were divided into two groups with and without angiotensin II (Ang II) administration (2.0 mg/kg . d) for 14 d, respectively. No morphological differences in the coronary artery and thoracic aorta were observed between the groups without Ang II. Ang II stimulation markedly increased medial thickness and perivascular fibrosis in ARKO mice, with enhanced TGF-beta1, collagen type I, and collagen type III gene expression in the aorta. Ang II stimulation also prominently increased superoxide production, lipid peroxidation, and gene expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase components in ARKO mice compared with WT mice. In addition, phosphorylation of c-Jun N-terminal kinase (JNK) and phosphorylated (Smad2/3) was remarkably enhanced in Ang II-treated ARKO mice compared with Ang II-treated WT mice. Notably, daily urinary nitric oxide (NO) metabolites excretion as a marker of NO bioavailability, aortic endothelial NO synthase expression and phosphorylation, and Akt phosphorylation were significantly reduced in ARKO mice compared with WT mice, regardless of Ang II stimulation. In conclusion, the androgen-AR system is required for the preservation of NO bioavailability through Akt-endothelial NO synthase system activation and exerts protective effects against Ang II-induced vascular remodeling by regulating oxidative stress, c-Jun N-terminal kinase (JNK) signaling, and the TGF-beta-phosphorylated Smad pathway.

The ontogenetic expression pattern of type 5 phosphodiesterase correlates with androgen receptor expression in rat corpora cavernosa

INTRODUCTION

The mechanisms controlling erection in animals and in humans are mainly age-dependent. However, the ontogenesis of the biochemical machinery of erection is largely unknown.

AIM

The aim of this article was to study the expression pattern of androgen receptor (AR) and the major cyclic guanosine monophosphate-hydrolyzing enzyme present in the corpora cavernosa, type 5 phosphodiesterase (PDE5), in the rat penis during development.

METHODS

AR and PDE5 expression was tested on ribonucleic acids (RNAs) and proteins extracted from the whole penis or from primary cultures of smooth muscle cells obtained from the corpora cavernosa of 3- (rCC3), 20- (rCC20), and 60- (rCC60) day-old rats. Rat corpus cavernosum cells were characterized by immunocytochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR).

MAIN OUTCOME MEASURES

Expression of PDE5 and AR messenger RNA (mRNA) and protein have been measured by RT-PCR and Western blot, respectively.

RESULTS

A significant increase in PDE5 mRNA expression was observed with RT-PCR from prepuberty to adulthood (0.5 +/- 0.06 vs. 1.6 +/- 0.046 arbitrary units [a.u.]P = 0.049). This age-dependent increase was mirrored by the increase in PDE5 protein expression found when comparing neonatal to adult corpus cavernosum smooth muscle cells (1.5 +/- 0.26 vs. 4.9 +/- 0.59 a.u. P = 0.0038) and the further 1.6-fold increase from rCC20 to rCC60 (4.9 +/- 0.59 vs. 8.0 +/- 0.8 a.u. P = 0.0024). This is the first demonstration of the ontogenetic profile of PDE5 expression in corpus cavernosum smooth muscle. As it has been demonstrated that androgens control PDE5 expression and that PDE5 inhibitors need an optimal androgenic milieu to act perfectly on erection, the expression of AR protein in rat corpus cavernosum cells was then tested by Western blot. A 7.0-fold increase was observed in primary cultured cells from 3 to 60 days old (1.4 +/- 0.38 vs. 9.8 +/- 1.3 a.u. P = 0.0052).

CONCLUSION

The increase in ARs during rat penile development parallels that of PDE5 RNA and protein, thus suggesting a positive effect of androgens on PDE5 expression.

Cardiovascular risk in normal weight, eumenorrheic, nonhirsute daughters of patients with polycystic ovary syndrome: a pilot study

OBJECTIVE

To verify whether healthy daughters with polycystic ovaries (PCO) of patients with polycystic ovary syndrome (PCOS) have an increased risk of cardiovascular disease in comparison with healthy controls.

DESIGN

Prospective observational study.

SETTING

University hospital.

PATIENT(S)

Seventeen eumenorrheic daughters with PCO of patients with PCOS (group 1) and 20 healthy volunteers (group 2) with regular ovulatory cycles.

INTERVENTION(S)

Fasting blood sampling, ultrasonographic and Doppler analyses, 24-hour ambulatory blood pressure monitoring.

MAIN OUTCOME MEASURE(S)

Medical examination; blood measurement of nitrites and nitrates, biochemical and hormonal parameters; utero-ovarian ultrasonographic analysis and color Doppler evaluation of uterine and stromal ovarian arteries; brachial artery flow-mediated vasodilatation; 24-hour ambulatory blood pressure monitoring. An oral glucose tolerance test was performed to analyze glucose, insulin, and C-peptide levels.

RESULT(S)

At Doppler analysis a significantly higher uterine and a lower ovarian artery pulsatility index was found in group 1 compared with group 2. The brachial artery diameter, after the reactive hyperemia, showed a greater vasodilatation in controls in comparison with women with PCO. The 24-hour blood pressure monitoring demonstrated that patients with PCO have significant higher 24-hour, daytime, and nighttime diastolic and mean arterial pressure values than controls. The nitrites and nitrates plasma levels were lower in group 1 compared with group 2. The glucose and insulin plasma values were higher in patients with PCO than in controls.

CONCLUSION(S)

Eumenorrheic nonhirsute daughters of patients with PCOS who have PCO appearance on ultrasound have an increased cardiovascular risk.

Diabetes mellitus, hypothalamic hypoestrogenemia, and coronary artery disease in premenopausal women (from the National Heart, Lung, and Blood Institute sponsored WISE study)

Diabetes mellitus (DM) portends a higher risk of coronary heart disease mortality in women compared with men. This relationship appears to be independent of traditional cardiac risk factors, and the role of reproductive hormones has been postulated. We assessed the relationship between DM, hypothalamic hypoestrogenemia (HHE), angiographic coronary artery disease (CAD), and major adverse cardiovascular events (MACE) during a median of 5.9 years in premenopausal women enrolled in the WISE Study. We evaluated 95 premenopausal women from WISE who underwent coronary angiography for suspected ischemia and were not using exogenous reproductive hormones. Results showed no difference in age between women with (n = 30) and without (n = 65) DM (43 +/- 6 years). DM was associated with hypertension, HHE, angiographic CAD, and coronary artery severity score (all p <0.05). Women with DM were twice as likely to have HHE (50% vs 26%; p = 0.02) compared with women without DM. The presence of both DM and HHE was associated with increased prevalence (40% vs 12% or 13%; p = 0.006) and severity of angiographic CAD (coronary artery severity score 19.9 +/- 19.2 vs 7.7 +/- 4.6 or 12.3 +/- 18.8; p = 0.008) compared with either HHE or DM alone, respectively. DM was moderately predictive of MACE. In conclusion, in premenopausal women undergoing coronary angiography for suspected myocardial ischemia, DM was associated with HHE. The presence of both DM and HHE predicted a greater burden of angiographic CAD. Prospective research is warranted to better understand causal relations between DM, endogenous hormones, and MACE in premenopausal women.

Estrogen potentiates constrictor prostanoid function in female rat aorta by upregulation of cyclooxygenase-2 and thromboxane pathway expression

Estrogen potentiates vascular reactivity to vasopressin (VP) by enhancing constrictor prostanoid function. To determine the cellular and molecular mechanisms, the effects of estrogen on arachidonic acid metabolism and on the expression of constrictor prostanoid pathway enzymes and endoperoxide/thromboxane receptor (TP) were determined in the female rat aorta. The release of thromboxane A2 (TxA2) and prostacyclin (PGI2) was measured in male (M), intact-female (Int-F), ovariectomized-female (OvX-F), and OvX + 17beta-estradiol-replaced female (OvX + ER-F) rats. The expression of mRNA for cyclooxygenase (COX)-1, COX-2, thromboxane synthase (TxS), and TP by aortic endothelium (Endo) and vascular smooth muscle (VSM) of these four experimental groups was measured by RT-PCR. The expression of COX-1, COX-2, and TxS proteins by Endo and VSM was also estimated by immunohistochemistry (IHC). Basal release of TxA2 and PGI2 was similar in M (18.8 +/- 1.9 and 1,723 +/- 153 pg/mg ring wt/45 min, respectively) and Int-F (20.2 +/- 4.2 and 1,488 +/- 123 pg, respectively) rat aortas. VP stimulated the dose-dependent release of TxA2 and PGI2 from both male and female rat aorta. OvX markedly attenuated and ER therapy restored VP-stimulated release of TxA2 and PGI2 in female rats. No differences in COX-1 mRNA levels were detected in either Endo or VSM of the four experimental groups (P > 0.1). The expression of both COX-2 and TxS mRNA were significantly higher (P < 0.05) in both Endo and VSM of Int-F and OvX + ER-F, compared with M or OvX-F. Expression of TP mRNA was significantly higher in VSM of Int-F and OvX + ER-F compared with M or OvX-F. IHC revealed the uniform staining of COX-1 in VSM of the four experimental groups, whereas staining of COX-2 and TxS was greater in Endo and VSM of Int-F and OvX + ER-F than in OvX-F or M rats. These data reveal that estrogen enhances constrictor prostanoid function in female rat aorta by upregulating the expression of COX-2 and TxS in both Endo and VSM and by upregulating the expression of TP in VSM.

Oestrogen synthesis, oestrogen metabolism and functional oestrogen receptors in bovine aortic endothelial cells

In order to investigate the mechanisms by which oestrogenic hormones influence the vascular system, we have studied their metabolism and the functioning of oestrogen receptors in bovine aortic endothelial cells from primo-secondary cultures, a widely studied model of vascular pathophysiology. We have demonstrated the enzymic activity of oestradiol-17 beta-hydroxysteroid dehydrogenase, 17-ketoreductase and aromatase in these cells. Immunocytochemical analyses, using two different monoclonal antibodies that recognize epitopes in the A/B domain of the oestrogen receptor, showed that this molecule has a predominantly cytoplasmic localization even after the addition of oestrogen to the culture medium. We showed that the hormone-receptor complexes were functional by demonstrating their transactivating ability in transfection experiments using the luciferase gene reporter and an oestrogen-responsive element transcriptional enhancer, although the amplitude of the response was in the range of only 140-150%: this was not a consequence of the presence of a specific limiting factor, but instead might be related to the peculiar subcellular localization of the oestrogen receptor.

Color Doppler sonographic analysis of uterine and ovarian artery blood flow in women with polycystic ovary syndrome

PURPOSE

To study the blood flow patterns of utero-ovarian circulation in polycystic ovary syndrome (PCOS) and to assess their relationship with clinical, metabolic, and hormonal data.

METHODS

Forty-three women with PCOS and 43 age-matched healthy controls underwent Doppler examination of the utero-ovarian circulation in the follicular phase. Demographic, hormonal, and metabolic parameters were determined. Student's t-test, chi(2)-test, and Spearman correlation test were used for statistical analysis.

RESULTS

The ovarian artery pulsatility index (PI), resistance index (RI), and SD ratios were significantly lower in PCOS than in controls on the right side (p < 0.001, p = 0.02, p = 0.001, respectively) as well as on the left side (p < 0.001, p < 0.001, p < 0.001, respectively). The uterine artery systolic/diastolic (S/D) ratio was higher on both sides (p = 0.01) and the PI was higher on the left side (p = 0.02) in PCOS than in controls. The right uterine artery PI was positively correlated with luteinizing hormone and hemoglobin (r = 0.417, p = 0.043; r = 0.427, p = 0.033, respectively), the right uterine artery S/D was positively correlated with body mass index (r = 0.479, p = 0.015), and the left uterine artery PI was positively correlated with insulin (r = 0.458, p = 0.021).

CONCLUSION

Doppler sonography of the utero-ovarian circulation may contribute to the evaluation of PCOS patients and a better understanding of the pathophysiology of this syndrome.

Endothelin-1-induced femoral head epiphyseal artery constriction is enhanced by long-term corticosteroid treatment

BACKGROUND

With regard to the pathogenesis of corticosteroid-associated femoral head osteonecrosis, only intravascular and extravascular factors have been discussed. Wall constriction of the lateral epiphyseal arteries, which are the main supplying arteries within the femoral head, has not previously been investigated. This study examined the effect of long-term corticosteroid treatment on vasoconstriction of the lateral epiphyseal arteries of the femoral head in a porcine model.

METHODS

The immature female Danish Landrace pig was chosen as the model for our study because femoral head osteonecrosis can be induced in this animal and because the lateral epiphyseal arteries of the femoral heads are of the appropriate size for myographic investigation. Twenty-four female Danish Landrace pigs (two siblings from each of twelve litters for a total of twelve sibling pairs) were divided by randomly separating the sibling pairs into two groups, with a total of twelve pigs in each group. One group of twelve animals received a daily dose of 100 mg of methylprednisolone orally for three months. The other group of twelve pigs served as controls and received no corticosteroids. After the animals were killed with an intravenous injection of pentobarbital, the lateral epiphyseal arteries of the femoral head were isolated from the cancellous bone. These arteries were mounted as ring preparations on a small-vessel myograph for measurement of isometric force development. The effects on the resected vessels of the vasoactive agents endothelin-1, noradrenaline, bradykinin, substance P, and nitrous oxide were investigated.

RESULTS

Vasoconstriction induced by increasing doses of endothelin-1 was increased after three months of methylprednisolone treatment compared with the vasoconstriction in vessels from control animals. Sensitivity to noradrenaline was not altered by this treatment. After submaximal precontraction by noradrenaline, vasorelaxation was elicited by substance P, nitrous oxide, and increasing doses of bradykinin without differences between the corticosteroid-treated and the control groups.

CONCLUSIONS

Endothelin-1-induced vasoconstriction of the epiphyseal arteries of the femoral head was increased in this corticosteroid-treated pig model. Such vasoconstriction may lead to a reduction in femoral head blood flow and to local ischemia and thus may be a newly described factor in the multifactorial pathomechanism of osteonecrosis of the femoral head.

Femoral artery constriction by norepinephrine is enhanced by methylprednisolone in a rat model

BACKGROUND

Corticosteroids are associated with femoral head osteonecrosis and arterial hypertension. The patho-mechanism of femoral head osteonecrosis is often attributed to ischemia. The aim of this study was to investigate if corticosteroids directly constrict the femoral artery or if they have a permissive effect on norepinephrine and endothelin-1-induced vasoconstriction.

METHODS

Femoral artery segments were harvested from twenty Wistar rats and mounted as ring preparations on a small-vessel myograph for the purpose of making isometric force measurements. For the norepinephrine study, twenty femoral artery segments from ten rats were stimulated cumulatively with norepinephrine before and after incubation with methylprednisolone (5 mug/mL). For the endothelin-1 study, forty femoral artery segments from ten rats were used. The four artery segments from each animal were randomized by pairs to either a corticosteroid treatment group (5 mug/mL methylprednisolone incubation, n = 20) or a control group (placebo incubation, n = 18, as two of the twenty control-group vessels did not meet protocol requirements). Isometric wall tension was plotted and quantified by the EC(50) (the plasma concentration of endothelin-1 required for obtaining 50% of maximal constriction in vivo).

RESULTS

In the norepinephrine-stimulated group, incubation with methylprednisolone did not directly induce any vasoconstriction but did enhance norepinephrine-elicited vasoconstriction. The norepinephrine dose-response curve displayed a shift to the left after incubation with methylprednisolone. This shift was reflected by a significantly lower mean EC50 of 9.5 x 10(-7) M +/- 5.1 x 10(-7) M after methylprednisolone incubation compared with a mean of 2.5 x 10(-6) M +/- 1.1 x 10(-6) M before incubation (p < 0.005). In the endothelin-1-stimulated group, the endothelin-1 dose-response curve displayed a tendency toward stronger contraction in the vessels that were incubated with methylprednisolone, but this tendency did not reach significance.

CONCLUSIONS

Incubation with methylprednisolone enhances norepinephrine-mediated contraction of the femoral artery in a rat model.

CLINICAL RELEVANCE

Vasoconstriction of the vascular bed supplying the femoral head can diminish femoral head blood flow, and this may be a factor in the early pathogenesis of corticosteroid-associated femoral head osteonecrosis.

Complex actions of sex steroids in adipose tissue, the cardiovascular system, and brain: Insights from basic science and clinical studies

Recent publications describing the results of the Women's Health Initiative (WHI) and other studies reporting the impact of hormone therapy on aging women have spurred reexamination of the broad use of estrogens and progestins during the postmenopausal years. Here, we review the complex pharmacology of these hormones, the diverse and sometimes opposite effects that result from the use of different estrogenic and progestinic compounds, given via different delivery routes in different concentrations and treatment sequence, and to women of different ages and health status. We examine our new and growing appreciation of the role of estrogens in the immune system and the inflammatory response, and we pose the concept that estrogen's interface with this system may be at the core of some of the effects on multiple physiological systems, such as the adipose/metabolic system, the cardiovascular system, and the central nervous system. We compare and contrast clinical and basic science studies as we focus on the actions of estrogens in these systems because the untoward effects of hormone therapy reported in the WHI were not expected. The broad interpretation and publicity of the results of the WHI have resulted in a general condemnation of all hormone replacement in postmenopausal women. In fact, careful review of the extensive literature suggests that data resulting from the WHI and other recent studies should be interpreted within the narrow context of the study design. We argue that these results should encourage us to perform new studies that take advantage of a dialogue between basic scientists and clinician scientists to ensure appropriate design, incorporation of current knowledge, and proper interpretation of results. Only then will we have a better understanding of what hormonal compounds should be used in which populations of women and at what stages of menopausal/postmenopausal life.

Corticosteroids and the cardiovascular response to stress: a pilot study of the 35% CO2 challenge in Addison's disease

OBJECTIVE

Glucocorticoids play an essential role in the neuroendocrine response to stress, influencing both the hypothalamic-pituitary-adrenal (HPA) axis and the sympatho-adrenomedullary (SAM) axis at several levels. In this pilot study, a clinical model of primary adrenocortical failure (Addison's disease, AD) has been used to evaluate the role of circulating glucocorticoids in both the autonomic and psychological response to stress.

DESIGN AND SUBJECTS

Five subjects with known AD underwent a randomized, double-blind, placebo-controlled investigation in which they received fixed glucocorticoid plus mineralocorticoid hormone replacement or placebo for 48 h prior to a 35% CO2 challenge.

MEASUREMENT

Psychological responses immediately before and after CO2 exposure were assessed by questionnaire. Systolic blood pressure (SBP) and heart rate were measured automatically at 1-min intervals for 5 min before and 5 min after the CO2 exposure.

RESULTS

While on hormone replacement, all subjects had an identical response to CO2 to that recorded in normal volunteers (initial bradycardia, an increase in blood pressure and subjective feelings of anxiety). On no replacement, however, the bradycardia and anxiety responses were not significantly altered, but the pressor response was markedly attenuated (+15.6 +/- 5 mmHg on replacement compared with +4.2 +/- 3.3 mmHg off replacement; P = 0.043).

CONCLUSIONS

These data provide further evidence that the CO2-induced bradycardia is a direct--presumably parasympathetic--response to CO2 independent of the pressor effect, and that the pressor response itself is dependent on the presence of the circulating corticosteroid.

Benefit and safety of 28-day transdermal estrogen regiment during vaginal hysterectomy (a controlled trial)

OBJECTIVES

Assessment of benefit and safety of 28-day transdermal 17-beta estradiol regimen during vaginal hysterectomy.

METHODS

Two-hundred and sixty-nine postmenopausal women, undergoing vaginal hysterectomy were divided into: transdermal estrogen hormone replacement therapy (TEHRT) group (n=119) with 28-day transdermal 17-beta estradiol 50 mg/day, 14 days before and after operation; and vaginal estrogen hormone replacement therapy (VEHRT) group (n=150) with 14-day preoperative vaginal conjugated estrogen 0.625 mg/day. The effect on: endometrium, wound healing, infection, recurrent organ prolapse were evaluated.

RESULTS

Pain symptoms, vaginal fetid discharge, swelling, crusting (p<0.001); visible wound opening on the 4 week control (p<0.01); patient assessment of outcome (p<0.001) were in favor of TEHRT. On the fifth postoperative day, VEHRT group showed: higher leukocytes increase (p<0.01); more patients with leukocytes count higher than 15x10(9) L(-1) (p<0.001) and afternoon body temperature higher than 38 degrees C (p<0.01). On the last follow-up control (VEHRT--28.3 months and TEHRT--24.5 months) TEHRT group had more patients with stage 0 of the apical segment (p<0.05). Point C was higher and total vaginal length longer in TEHRT group (p<0.01; p<0.05). Frequency, constipation, painful coitus, incontinence during intercourse were more frequent in VEHRT (p<0.001; p<0.05; p<0.05; p<0.05). Endometrium with a thickness between 2 and 4 mm, was more frequent in the TEHRT group (p<0.05). There were no significant differences in occurrence of more thickened endometrium and more significant morphological changes (endometrial polyp, simplex hyperplasia) between the groups. In none of the patients from the both study groups complex hyperplasia, atypical hyperplasia or endometrial carcinoma were observed.

CONCLUSIONS

The 28-day transdermal 17-beta estradiol regimen seems to be safe and effective procedure.

Estrogen potentiates vasopressin-induced contraction of female rat aorta by enhancing cyclooxygenase-2 and thromboxane function

To determine the roles of estrogen and constrictor prostanoids in vasopressin (VP)-induced contraction of female rat aorta, vascular reactivity to VP was determined in thoracic aortas of intact, ovariectomized, and ovariectomized + estrogen-replaced female rats in the presence of indomethacin (Indo), NS-398, SQ-29,548, or vehicle control. The effects of estrogen on vascular reactivity to the thromboxane A(2) analog U-46619 were also examined. Maximal contractile response to VP in intact female rats (5,567 +/- 276 mg/mg of aortic ring wt) was markedly attenuated by ovariectomy (2,485 +/- 394 mg; P < 0.001) and restored by estrogen replacement with 17beta-estradiol (5,059 +/- 194 mg; P > 0.1). Indo and NS-398 significantly attenuated maximal responses to VP in intact female rats to a similar extent [3,176 +/- 179 (P < 0.0001) and 3,258 +/- 152 mg (P < 0.0001), respectively]. Ovariectomy abolished and estrogen replacement restored the inhibitory effects of Indo, NS-398, and SQ-29,548. Contractile responses of rat aorta to U-46619 were significantly greater (P < 0.0001) in females (5,040 +/- 238 mg) than in males (3,679 +/- 96 mg). Ovariectomy markedly attenuated (3,923 +/- 84 mg; P < 0.01) and estrogen replacement restored (5,024 +/- 155 mg; P > 0.1) responses to U-46619 in female aortas. These data reveal that estrogen is an important regulator of the contractile responses of female rat aorta to VP, which appears to potentiate both cyclooxygenase-2 and constrictor prostanoid function in the vascular wall.

Doppler sonography of the normal lacrimal gland

PURPOSE

We used Doppler sonography to determine the resistance index (RI) and pulsatility index (PI) of the normal lacrimal artery (LA) in both females and males. We also compared the values obtained at various periods of reproductive life.

METHODS

The study was performed in 25 prepubertal girls, 28 females of reproductive age, and 27 postmenopausal women, 23 pregnant women, and 104 healthy males. Doppler sonography was used to determine the RI and PI of the LA.

RESULTS

The mean PI for the entire patient population was 1.48 +/- 0.60 and the RI was 0.72 +/- 0.09. The RI and PI values of the LA did not differ between males and females. Similarly, the mean RI and PI values of the LA did not change significantly between the various reproductive phases.

CONCLUSION

The PI and RI of the lacrimal gland are similar in both sexes. Moreover, they are not altered by changes in levels of sex steroids.

Divergent effects of estrogen and nicotine on Rho-kinase expression in human coronary vascular smooth muscle cells

Recent studies have demonstrated that up-regulated Rho-kinase plays an important role in the pathogenesis of coronary arteriosclerosis and vasospasm. We have shown that inflammatory stimuli, such as angiotensin II and interleukin-1beta, up-regulate Rho-kinase expression and activity in human coronary vascular smooth muscle cells, for which intracellular signal transduction mediated by protein kinase C and NF-kappaB is involved. Here, we show that estrogen down-regulates while nicotine up-regulates Rho-kinase and that nicotine counteracts the inhibitory effect of estrogen on angiotensin II-induced Rho-kinase expression. Furthermore, we demonstrated that the intracellular signal transduction of the inhibitory effect of estrogen is mediated by an estrogen receptor. These results demonstrate that inflammatory stimuli up-regulate Rho-kinase, for which estrogen (mediated by an estrogen receptor) and nicotine exert divergent inhibitory and stimulatory effects on the Rho-kinase expression, respectively, and may explain in part why the incidence of arteriosclerotic and vasospastic disorders is increased in postmenopausal women and smokers.

Tibolone, oral or transdermal hormone replacement and colour Doppler analysis

OBJECTIVE

To compare the plasma thromboxane, the plasma viscosity and the Doppler flow modifications induced by tibolone and by oral or transdermal continuous combined hormone replacement therapy.

METHODS

Forty-two post-menopausal patients underwent either on: oral daily treatment with tibolone (2.5 mg) (Group I; n= 14); or continuous oral administration of 0.625 mg conjugated equine estrogens + medroxyprogesterone 5 mg per day (Group II; n = 14 ); or continuous estradiol transdermal supplementation, at a dose of 50 microg per day, + medroxyprogesterone 5 mg per day (Group III; n = 14 ). The duration of the study was 6 months and the patients were submitted to transvaginal ultrasonographic evaluation of pelvic organs; Doppler analysis of the uterine, internal carotid and ophthalmic arteries; thromboxane and plasma viscosity assays in basal condition, and at 1, 3 and 6 months from the beginning of the study.

RESULTS

Although the endometrial thickness increased significantly, there were no cases in which it exceeded the normal range (< or = 5 mm). In all the three groups, the pulsatility index of the uterine, internal carotid and ophthalmic arteries significantly decreased during the therapy showing a reduced impedance since the first month of treatment. Similar variations were observed for the peak systolic blood flow velocity of the internal carotid and ophthalmic arteries. Hormone replacement therapy and tibolone induced a deep, significant and rapid decrease in plasma thromboxane and plasma viscosity levels.

CONCLUSIONS

Hormone replacement therapy and tibolone seem to have beneficial effects on vascular and hemorrheological parameters.

Methylprednisolone enhances contraction of porcine femoral head epiphyseal arteries

The pathomechanism of steroid-induced femoral head necrosis is thought to be disturbed femoral head blood flow. We hypothesize that methylprednisolone increases vasocontraction of femoral head epiphyseal arteries, thereby reducing femoral head blood flow. Nine immature female domestic pigs were randomly selected from a group of 18 to receive 24-hour methylprednisolone treatment, whereas the nine remaining pigs received the placebo control in a blinded fashion. After sacrifice, lateral epiphyseal artery segments from the femoral heads were mounted as ring preparations on a small vessel myograph. Isometric active tension was measured in relation to cumulating doses of the vasoconstrictors noradrenaline and endothelin-1, and the vasodilator bradykinin. Vasocontraction to noradrenaline was not altered by methylprednisolone. Bradykinin elicited a concentration-dependent vasodilation which was lower in the corticosteroid-treated vessels. Vasoconstriction to endothelin-1 was stronger in the corticosteroid-treated vessels. Our data indicate that methylprednisolone enhances contraction of femoral head lateral epiphyseal arteries and may decrease femoral head blood flow. To our knowledge, this pathomechanic factor in femoral head necrosis has not been described before.

Hormone therapy and ophthalmic artery blood flow changes in women with primary open-angle glaucoma

OBJECTIVE

To compare the effects of hormone therapy (HT) on plasma viscosity and Doppler flow parameters in normal, healthy, postmenopausal women and in women with normal-tension and chronic, open-angle glaucoma.

DESIGN

Eight postmenopausal women with glaucoma (group I) and 15 controls (group II) were given HT. The duration of the study was 6 months, and the women were examined in basal condition and at the end of the treatment. All women underwent ultrasonographic evaluation of pelvic organs and color Doppler analysis of uterine, internal carotid, and ophthalmic arteries. Also, plasma viscosity was assayed.

RESULTS

The ultrasonographic analysis showed that none of the women presented with irregular endometrial echoes, polyps, or intracavitary fluid. In addition, endometrial thickness never exceeded the normal range (5 mm). Plasma viscosity and Doppler parameters significantly improved during therapy. However, the ophthalmic artery mean improvements of pulsatility index (-43% v -28%; P = 0.001), peak systolic blood flow velocity (+35% v +24%; P = 0.026), and time-averaged maximum velocity (+44% v +32%; P = 0.031) were significantly more evident in the control group than in the glaucoma group.

CONCLUSIONS

Although, in people with glaucoma, vasospasm can increase the risk of visual loss by inducing a retrobulbar blood flow reduction, HT seems to beneficially affect the ocular vascularization.

Endogenous sex hormones and progression of carotid atherosclerosis in elderly men

BACKGROUND

The burden of atherosclerosis especially afflicts the increasing older segment of the population. Recent evidence has emphasized a protective role of endogenous sex hormones in the development of atherosclerosis in aging men.

METHODS AND RESULTS

We studied the association between endogenous sex hormones and progression of atherosclerosis in 195 independently living elderly men. Participants underwent measurements of carotid intima-media thickness (IMT) at baseline in 1996 and again in 2000. At baseline, serum concentrations of testosterone (total and free) and estradiol (total and free E2) were measured. Serum free testosterone concentrations were inversely related to the mean progression of IMT of the common carotid artery after adjustment for age (beta=-3.57; 95% CI, -6.34 to -0.80). Higher serum total and free E2 levels were related to progression of IMT of the common carotid artery after adjustment for age (beta=0.38; 95% CI, -0.11 to 0.86; and beta=0.018; 95% CI, -0.002 to 0.038, respectively). These associations were independent of body mass index, waist-to-hip ratio, presence of hypertension and diabetes, smoking, and serum cholesterol levels

CONCLUSIONS

Low free testosterone levels were related to IMT of the common carotid artery in elderly men independently of cardiovascular risk factors.

Effect of androgens on penile tissue

There are two ways to establish that androgens play a major role in the function and integrity of erectile tissue: (1) discussing a number of physiology and molecular biology studies that have been published from experiments in animals and (2) reporting the effect of androgens on penile tissue, or in many cases the lack of androgen, in man. A variety of animal models, and also human studies, have shown the existence of androgen receptors in the corpora cavernosa. The penile erectile response in the laboratory rat is androgen dependent, and the active androgen appears to be dihydrotestosterone. There are several articles that describe the androgenic regulation of nitric oxide synthase (the enzyme responsible for production of nitric oxide), the primary agent controlling the erectile cycle. There have been few reports showing a direct end organ dependency of androgen for erectile function in the human corpora cavernosa, although there is plenty of evidence demonstrating that low or absent androgens affect a man's ability to have an erection in a sexual situation. Thus, in man androgen dependency for cavernous tissue smooth muscle function is still debatable. Extrapolating animal dependency of androgens for molecular activity in the penile tissue remains the most reasonable suggestion for androgen dependency of the cavernous tissue in man.

The influence of sex hormones on ocular blood flow in women

PURPOSE

To investigate the influence of sex hormones on ocular haemodynamics, blood flow velocities in the ophthalmic and central retinal arteries and serum levels of sex hormones were measured in pre- and postmenopausal women.

METHODS

Colour Doppler imaging (CDI) was used to determine the flow velocities (peak systolic velocity [PSV] and end-diastolic velocity [EDV]) and the resistive index (RI) in the ophthalmic and central retinal arteries in 22 premenopausal and 32 postmenopausal women, who had never received hormone replacement therapy. Serum levels were measured for oestradiol, free testosterone and follicle-stimulating hormone. The CDI parameters were compared between the two groups and the influence of serum levels of oestradiol and testosterone on blood flow velocities and the resistive indices were analysed.

RESULTS

After correcting for age and mean arterial blood pressure, an analysis of covariance disclosed a significantly lower EDV (p=0.02) and a significantly higher RI (p=0.01) in the central retinal artery of postmenopausal women compared with premenopausal women. Partial correlation analysis, controlling for age, revealed significant correlations between the CDI parameters and serum levels of oestradiol and testosterone. For premenopausal women, PSV (r=0.58, p=0.04) and EDV (r=0.73, p=0.006) in the ophthalmic artery correlated positively with serum oestradiol levels. The RI in the central retinal artery decreased with increasing oestradiol levels in both groups (premenopausal r= -0.40, p=0.04; postmenopausal r= -0.32, p=0.05). Peak systolic velocity in the central retinal artery correlated negatively (r= -0.49, p=0.04), whereas the RI correlated positively (r=0.53, p=0.02) with testosterone levels in the premenopausal group. Postmenopausal women with higher testosterone levels had lower EDV (r= -0.53, p=0.007) in the central retinal artery and higher RI in both vessels (ophthalmic artery r=0.48, p=0.01; central retinal artery r=0.61, p=0.002).

CONCLUSION

Our data provide evidence of a relationship between serum sex hormone levels and blood flow velocities and resistive indices in retrobulbar arteries. Oestradiol appears to have beneficial effects on ocular haemodynamics, whereas testosterone may act as an antagonistic to the effects of oestrogen.

Gender, sex hormones, and vascular tone

The greater incidence of hypertension and coronary artery disease in men and postmenopausal women compared with premenopausal women has been related, in part, to gender differences in vascular tone and possible vascular protective effects of the female sex hormones estrogen and progesterone. However, vascular effects of the male sex hormone testosterone have also been suggested. Estrogen, progesterone, and testosterone receptors have been identified in blood vessels of human and other mammals and have been localized in the plasmalemma, cytosol, and nuclear compartments of various vascular cells, including the endothelium and the smooth muscle. The interaction of sex hormones with cytosolic/nuclear receptors triggers long-term genomic effects that could stimulate endothelial cell growth while inhibiting smooth muscle proliferation. Activation of plasmalemmal sex hormone receptors may trigger acute nongenomic responses that could stimulate endothelium-dependent mechanisms of vascular relaxation such as the nitric oxide-cGMP, prostacyclin-cAMP, and hyperpolarization pathways. Additional endothelium-independent effects of sex hormones may involve inhibition of the signaling mechanisms of vascular smooth muscle contraction such as intracellular Ca2+ concentration and protein kinase C. The sex hormone-induced stimulation of the endothelium-dependent mechanisms of vascular relaxation and inhibition of the mechanisms of vascular smooth muscle contraction may contribute to the gender differences in vascular tone and may represent potential beneficial vascular effects of hormone replacement therapy during natural and surgically induced deficiencies of gonadal hormones.

A multiparametric study of the action of mifepristone used in emergency contraception using the Rhesus monkey as a primate model

Mifepristone is a potent agent used in emergency contraception (EC). In the present study, we examined the contraceptive efficacy of mifepristone used in EC and then, using the model of mifepristone-based EC, we investigated its mechanism of action in the rhesus monkey. Sexually mature females were allowed to cohabitate with male animals from 1600 to 900 h of any one day of days 8-17 of cycle without (Group I; n = 6) and with a single dose of mifepristone (Group II, n = 31, 25 mg per animal, subcutaneous) 72 h postcoitus. Blood samples from all animals of Groups I and II were used to determine the concentrations of estradiol (E), progesterone (P) and chorionic gonadotrophin in peripheral circulation for retrospective analysis of the days of ovulation and blastocyst implantation. Four out of six animals (66.6%) in Group I became pregnant, while all 31 monkeys in Group II failed to establish pregnancy along with marginal changes in serum concentrations of E and P. In the second part of the study, animals were subjected to the same experimental protocol followed by collection of endometrial tissue samples on cycle day 22 from animals of both Group I (n = 6) and Group II (n = 24). Endometrial samples were subjected to morphological analysis including mitotic index, immunohistochemistry for vascular endothelial growth factor (VEGF), leukemia inhibitory factor (LIF), transforming growth factor beta1, estradiol receptor (ER), progesterone receptor (PR), proliferating cell nuclear antigen, placental protein 14 (PP 14) and detection of apoptosis by terminal nick end labeling method followed by histometric analysis. The results were retrospectively analyzed between the two groups on the basis of the day of treatment after ovulation: early luteal phase (days 0-3 postovulation) and mid-luteal phase (days 4-7 after ovulation). Mifepristone used in EC in the present study resulted in general loss of functional integrity of epithelial compartment characterized by loss of secretory maturation, increased apoptosis and higher degree of degeneration along with decreased expression of VEGF, LIF, PP14 and ER, while PR level increased as compared to control samples. The vascular compartment appeared to be compromised along with affected morphological features and decreased expression of VEGF, LIF, ER and PR following the administration of mifepristone. It appears that mifepristone used in EC alters the physiological homeostasis in epithelial and vascular compartments of implantation stage endometrium rendering it hostile to blastocyst implantation. Furthermore, the degree to which the endometrial function is affected largely depends on the day of mifepristone treatment in a parameter-specific manner resulting in a higher degree of degenerative changes in samples obtained from animals who received mifepristone during mid-luteal phase of cycles.