Hormone replacement therapy increases plasma level of angiotensin II in postmenopausal hypertensive women

Blockade of the kinin B1 receptor counteracts the depressive-like behaviour and mechanical allodynia in ovariectomised mice

Menopause is related to a decline in ovarian oestrogen production, affecting the perception of the somatosensory stimuli, changing the immune-inflammatory systems, and triggering depressive symptoms. It has been demonstrated that the inhibition of the kinin B₁ and B₂ receptors (B₁R and B₂R) prevented the depressive-like behaviour and the mechanical allodynia that was induced by immune-inflammatory mediators in mice. However, there is no evidence regarding the role of the kinin receptors in the depressive-like and nociceptive behaviour in female mice that were subjected to bilateral ovariectomy (OVX). This study has shown that the OVX mice developed time-related mechanical allodynia, together with an increased immobility time as indicative of depression. Both of these changes were reduced by the genetic deletion of B₁R, or by the pharmacological blockade of the selective kinin B₁R antagonist R-715 (acute, i.p.). The genetic deletion or the pharmacological inhibition of B₂R (HOE 140, i.p.) did not prevent the OVX-elicited behavioural changes. The data has suggested a particular modulation of kinin B₁R in the nociceptive and depressive-like behaviour in the OVX mice. The selective inhibition of the B₁R receptor may be a new pharmacological target for treating pain and depression symptoms in women during the perimenopause/menopause period.

Sex differences in the metabolic effects of the renin-angiotensin system

Obesity is a global epidemic that greatly increases risk for developing cardiovascular disease and type II diabetes. Sex differences in the obese phenotype are well established in experimental animal models and clinical populations. While having higher adiposity and obesity prevalence, females are generally protected from obesity-related metabolic and cardiovascular complications. This protection is, at least in part, attributed to sex differences in metabolic effects of hormonal mediators such as the renin-angiotensin system (RAS). Previous literature has predominantly focused on the vasoconstrictor arm of the RAS and shown that, in contrast to male rodent models of obesity and diabetes, females are protected from metabolic and cardiovascular derangements produced by angiotensinogen, renin, and angiotensin II. A vasodilator arm of the RAS has more recently emerged which includes angiotensin-(1-7), angiotensin-converting enzyme 2 (ACE2), mas receptors, and alamandine. While accumulating evidence suggests that activation of components of this counter-regulatory axis produces positive effects on glucose homeostasis, lipid metabolism, and energy balance in male animal models, female comparison studies and clinical data related to metabolic outcomes are lacking. This review will summarize current knowledge of sex differences in metabolic effects of the RAS, focusing on interactions with gonadal hormones and potential clinical implications.

Lack of change in serum angiotensin-converting enzyme activity during the menstrual cycle

Introduction. The Deletion (D) rather than Insertion (I) variant of the angiotensin-converting enzyme (ACE) gene is associated with higher circulating ACE activity. Meanwhile, coronary risk rises with the menstrual nadir in oestrogen levels, exogenous oestrogen reduces serum ACE activity (with a greater reduction the higher the baseline ACE activity), and pharmacological reduction in ACE activity is cardioprotective. Alterations in coronary risk associated with the menstrual cycle may thus be mediated through (genotype-dependent) changes in ACE activity. We have examined this hypothesis.

Materials and methods. Twenty-three healthy female subjects (12 II, 11 DD genotype) were studied. None were taking oral contraceptive agents. Blood was assayed for oestrogen, follicle stimulating hormone (FSH), luteinising hormone (LH), progesterone and ACE activity every three days throughout their menstrual cycle. Results ACE activity was unrelated to oestrogen, FSH or LH during the menstrual cycle, irrespective of ACE genotype.

Conclusions. The increase in myocardial ischaemia during low oestrogen phases of the menstrual cycle does not appear mediated through a fall in serum ACE activity.

Incidence of endometrial spotting or bleeding during continuous-combined estrogen-progestin therapy in postmenopausal women with and without hypertension

OBJECTIVE

Endometrial spotting or bleeding is a common adverse effect among women taking continuous-combined estrogen-progestin therapy. The renin-angiotensin-aldosterone system plays a major role in hypertension and is present in the endometrium. We hypothesized that postmenopausal women with hypertension would have a higher incidence of bleeding compared with postmenopausal women without hypertension.

METHODS

A multivariate mixed-effects logistic model estimated the odds ratios for the relationship of hypertension status or use of antihypertensive drugs with endometrial bleeding using the Women's Health Initiative database.

RESULTS

The incidence of spotting or bleeding in the first 12 months of estrogen-progestin use was 42% in women aged 50 to 79 years. Women with hypertension were more likely to experience bleeding than women without hypertension (odds ratio, 1.07; 95% CI, 1.02-1.13). Overall antihypertensive medication use increased bleeding with an odds ratio of 1.24, whereas angiotensin II receptor antagonists had a reduced odds ratio (0.53).

CONCLUSIONS

Postmenopausal women with hypertension are more likely to bleed than postmenopausal women without hypertension when taking continuous estrogen-progestin, with less bleeding in women using angiotensin II receptor antagonists. This finding is novel and supports our hypothesis that the endometrial renin-angiotensin-aldosterone system may contribute to endometrial bleeding.

Visceral adiposity index is highly associated with adiponectin values and glycaemic disturbances

BACKGROUND

Visceral Adiposity Index (VAI) is a gender-specific mathematical index estimated with the use of simple anthropometric (body mass index and waist circumference) and biochemical (triglycerides and high density lipoprotein cholesterol) parameters. Recent studies have shown that VAI reflects accurately the degree of visceral adiposity and insulin resistance. However, up to now, VAI has not been evaluated if it correlates with carbohydrate metabolism disorders, as well as with adipokine secretion from the fat mass.

METHODS

In a cohort of 308 out of 414 adult Saudi subjects screened for the study, detailed personal medical history, anthropometrics and metabolic/hormonal profiles were obtained. Additionally, the circulating concentrations of several circulating adipokines, namely adiponectin, leptin, tumour necrosis factor-α (TNF-α) and resistin, were measured.

RESULTS

Stepwise multivariate analysis showed that VAI was the sole determinant of adiponectin levels (R(2)  = 0·07, beta ± SE: -0·25 ± 0·05), while BMI and female gender predicted leptin levels (R(2)  = 0·26, 0·10 ± 0·01 and 0·61 ± 0·15, respectively). Furthermore, the presence of impaired fasting glucose (IFG)/diabetes was predicted only by age and VAI.

CONCLUSIONS

We report for the first time the direct relations of VAI with adipose tissue secretion, as well as with functional glycaemic disorders. Because VAI is estimated easily with data obtained in everyday practice, it could be used as an indirect index of adiponectin levels and the risk of impaired glucose metabolism.

Hypovitaminosis D associations with adverse metabolic parameters are accentuated in patients with Type 2 diabetes mellitus: a body mass index-independent role of adiponectin?

BACKGROUND

Hypovitaminosis D has been associated with an increased prevalence of Type 2 diabetes mellitus (DMT2) and metabolic syndrome manifestations. The purpose of this study was to examine the association between 25-hydroxy-vitamin D (25-OH-VitD) levels and indices of insulin resistance (IR), including adipocytokines, in a Saudi population with or without DMT2.

SUBJECTS AND METHODS

A total of 266 subjects (153 DMT2 and 113 healthy controls) aged 26-80 yr were randomly selected from the existing Biomarkers Screening in Riyadh Program (RIYADH Cohort). Subjects were assessed clinically, anthropometry was performed, morning blood chemistries, including fasting glucose (FG), triglycerides, total cholesterol, LDL cholesterol (LDL-C), and HDL cholesterol were obtained. Homeostasis model assessment of IR (HOMA-IR) was calculated, and serum 25-OH-VitD, leptin, adiponectin, resistin, insulin, high sensitivity CRP (hsCRP), and tumor necrosis factor α concentrations were measured using specific assays.

RESULTS

In DMT2 subjects, negative correlations between 25-OH-vitD and body mass index (BMI), FG, insulin, HOMA-IR, cholesterol, LDL-C, and hsCRP were observed, while a positive correlation between 25-OH-VitD and adiponectin was detected. The later remained significant after controlling for BMI. Interestingly, only weak and nonsignificant associations between 25-OH-VitD and metabolic parameters were observed in the control group, whereas, when the entire population was examined, negative correlations were evident primarily between 25-OH-VitD and FG, HOMA-IR, total cholesterol, LDL-C. These associations remained significant after controlling for BMI.

CONCLUSIONS

These results suggest that hypovitaminosis D associations with metabolic disturbances are accentuated in DMT2. The BMIindependent positive correlation between 25-OH-VitD and adiponectin suggests a potential role for this adipocytokine as a link between 25-OH-VitD and IR in patients with DMT2.

Oxidized CaMKII causes cardiac sinus node dysfunction in mice

Sinus node dysfunction (SND) is a major public health problem that is associated with sudden cardiac death and requires surgical implantation of artificial pacemakers. However, little is known about the molecular and cellular mechanisms that cause SND. Most SND occurs in the setting of heart failure and hypertension, conditions that are marked by elevated circulating angiotensin II (Ang II) and increased oxidant stress. Here, we show that oxidized calmodulin kinase II (ox-CaMKII) is a biomarker for SND in patients and dogs and a disease determinant in mice. In wild-type mice, Ang II infusion caused sinoatrial nodal (SAN) cell oxidation by activating NADPH oxidase, leading to increased ox-CaMKII, SAN cell apoptosis, and SND. p47-/- mice lacking functional NADPH oxidase and mice with myocardial or SAN-targeted CaMKII inhibition were highly resistant to SAN apoptosis and SND, suggesting that ox-CaMKII-triggered SAN cell death contributed to SND. We developed a computational model of the sinoatrial node that showed that a loss of SAN cells below a critical threshold caused SND by preventing normal impulse formation and propagation. These data provide novel molecular and mechanistic information to understand SND and suggest that targeted CaMKII inhibition may be useful for preventing SND in high-risk patients.

Parent-offspring transmission of adipocytokine levels and their associations with metabolic traits

Adipose tissue secreted cytokines (adipocytokines) have significant effects on the physiology and pathology of human metabolism relevant to diabetes and cardiovascular disease. We determined the relationship of the pattern of these circulating hormones with obesity-related phenotypes and whether such pattern is transmitted from parent to offspring. A combined total of 403 individuals from 156 consenting Saudi families divided into initial (119 families with 123 adults and 131 children) and replication (37 families with 58 adults and 91 children) cohorts were randomly selected from the RIYADH Cohort study. Anthropometrics were evaluated and metabolic measures such as fasting serum glucose, lipid profiles, insulin, leptin, adiponectin, resistin, tumor necrosis factor alpha (TNFα), activated plasminogen activator inhibitor 1 (aPAI1), high sensitivity C-reactive protein (hsCRP) and angiotensin II were also assessed. Parent-offspring regressions revealed that with the exception of hsCRP, all hormones measured showed evidence for significant inheritance. Principal component (PC) analysis of standardized hormone levels demonstrated surprising heritability of the three most common axes of variation. PC1, which explained 21% of the variation, was most strongly loaded on levels of leptin, TNFα, insulin, and aPAI1, and inversely with adiponectin. It was significantly associated with body mass index (BMI) and phenotypically stronger in children, and showed a heritability of ∼50%, after adjustment for age, gender and generational effects. We conclude that adipocytokines are highly heritable and their pattern of co-variation significantly influences BMI as early as the pre-teen years. Investigation at the genomic scale is required to determine the variants affecting the regulation of the hormones studied.

Adiposity and insulin resistance correlate with telomere length in middle-aged Arabs: the influence of circulating adiponectin

OBJECTIVE

Studies in obesity have implicated adipocytokines in the development of insulin resistance, which in turn may lead to accelerated aging. In this study, we determined associations of chromosomal telomere length (TL) to markers of obesity and insulin resistance in middle-aged adult male and female Arabs with and without diabetes mellitus type 2 (DMT2).

DESIGN AND METHODS

One hundred and ninety-three non-diabetic and DMT2 subjects without complications (97 males and 96 females) participated in this cross-sectional study. Clinical data, as well as fasting blood samples, were collected. Serum glucose and lipid profile were determined using routine laboratory methods. Serum insulin, leptin, adiponectin, resistin, tumor necrosis factor-α, and PAI-1 were quantified using customized multiplex assay kits. High sensitive C-reactive protein (hsCRP) and angiotensin II (ANG II) were measured using ELISAs. Circulating leukocyte TL was examined by quantitative real-time PCR.

RESULTS

Circulating chromosomal leukocyte TL had significant inverse associations with body mass index (BMI), systolic blood pressure, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), low-density lipoprotein (LDL)- and total cholesterol, ANG II and hsCRP levels. Adiponectin, BMI, systolic blood pressure, and LDL cholesterol predicted 47% of the variance in TL (P<0.0001). HOMA-IR was the most significant predictor for TL in males, explaining 35% of the variance (P=0.01). In females, adiponectin accounted for 28% of the variance in TL (P=0.01).

CONCLUSION

Obesity and insulin resistance are associated with chromosomal TL among adult Arabs. Evidence of causal relations needs further investigation. The positive association of adiponectin to TL has clinical implications as to the possible protective effects of this hormone from accelerated aging.

Relationship between resistin and aPAI-1 levels with insulin resistance in Saudi children

BACKGROUND

Association of resistin with insulin resistance (IR) in humans is still controversial and few studies have investigated the association of plasminogen activator inhibitor-1 (PAI-1) with IR in children. The purpose of the present study was therefore to evaluate serum levels of resistin and active PAI-1 (aPAI-1) in Saudi children and their association with the various obesity-related complications.

METHODS

In this cross-sectional study, 73 boys and 77 girls with varying body mass index (BMI) were recruited. They were assessed for anthropometric measures and fasting serum levels of glucose, insulin, lipid profile, resistin, angiotensin II (ANG II) and aPAI-1.

RESULTS

Resistin was positively correlated with hips (r = 0.33, P < 0.01), waist (r = 0.23, P < 0.05) and BMI (r = 0.33, P < 0.01). The association of resistin with the markers of obesity was also significant in girls but lost significance in boys. aPAI-1 was positively correlated with total cholesterol (r = 0.24; P < 0.01), triglycerides (r = 0.2, P < 0.05), HOMA-IR (r = 0.26, P < 0.01) and insulin (r = 0.26, P < 0.01). The significant association of aPAI-1 with IR was also true in girls but lost significance in boys.

CONCLUSION

Resistin is not correlated with IR and further studies are needed to explore the role of resistin especially in childhood obesity. In contrast, increased levels of PAI-1 may contribute to the risk of cardiovascular diseases related to obesity and insulin resistance in children. The observed gender-related differences in the association between resistin, aPAI-1 with obesity markers and IR could be attributed to sexual dimorphism in body fat distribution.

Gender differences in cardiovascular disease: hormonal and biochemical influences

OBJECTIVE

Atherosclerosis is a complex process characterized by an increase in vascular wall thickness owing to the accumulation of cells and extracellular matrix between the endothelium and the smooth muscle cell wall. There is evidence that females are at lower risk of developing cardiovascular disease (CVD) as compared to males. This has led to an interest in examining the contribution of genetic background and sex hormones to the development of CVD. The objective of this review is to provide an overview of factors, including those related to gender, that influence CVD.

METHODS

Evidence analysis from PubMed and individual searches concerning biochemical and endocrine influences and gender differences, which affect the origin and development of CVD.

RESULTS

Although still controversial, evidence suggests that hormones including estradiol and androgens are responsible for subtle cardiovascular changes long before the development of overt atherosclerosis.

CONCLUSION

Exposure to sex hormones throughout an individual's lifespan modulates many endocrine factors involved in atherosclerosis.

Long-term effects of telmisartan on blood pressure, the renin-angiotensin-aldosterone system, and lipids in hypertensive patients

We prospectively evaluated long-term (12 months) effects of telmisartan on blood pressure (BP), circulating renin-angiotensin-aldosterone levels, and lipids in hypertensive patients. There were 13 men and 11 women, 59 +/- 8.7 years of age (mean +/- SEM), with untreated essential hypertension. The 20-60 mg doses of telmisartan were administered once daily in the morning until BP130/85 was obtained. Blood pressure and plasma renin activity, plasma angiotensin (Ang) I and Ang II, serum angiotensin-converting enzyme (ACE) activity, plasma aldosterone concentration, plasma human atrial natriuretic peptide (hANP) concentration, and serum lipids were obtained 6 and 12 months after starting telmisartan administration. Systolic and diastolic BP were significantly (P < 0.001, P < 0.001) decreased from 162 +/- 3.3 and 97.7 +/- 2.1 mmHg to 128 +/- 3.8 and 79.6 +/- 2.0 mmHg after 12 months of treatment, respectively. Plasma Ang I and Ang II were unchanged at 12 months. Plasma renin activity and serum ACE activity were significantly (P < 0.001, P < 0.05) increased and plasma aldosterone concentration was unchanged during the study period. Total cholesterol levels were unchanged, but serum triglycerides levels were significantly decreased at 12 months (P < 0.01). Plasma hANP showed no significant alteration throughout the 12-month period. In hypertensive patients, telmisartan is a beneficial antihypertensive drug that also lowers serum triglycerides.

Effects of raloxifene on the renin-angiotensin-aldosterone system and blood pressure in hypertensive and normotensive osteoporotic postmenopausal women

AIM

An increase in blood pressure after menopause has been documented. The renin-angiotensin-aldosterone system (RAAS) plays a central role in the regulation of blood pressure and in the pathophysiology of hypertension. This study investigated the effects of raloxifene, a selective estrogen receptor modulator, on components of the RAAS and blood pressure in hypertensive and normotensive osteoporotic postmenopausal women.

METHODS

A total of 41 hypertensive or normotensive postmenopausal women with osteoporosis or osteopenia were divided into four groups. Eleven hypertensive and eight normotensive women received raloxifene hydrochloride (60 mg/day) p.o. for 6 months, and 12 hypertensive and 10 normotensive women did not receive raloxifene hydrochloride for 6 months. In all of the hypertensive women, blood pressure had been controlled prior to the start of the study using a variety of antihypertensive drugs other than angiotensin-converting enzyme (ACE) inhibitors, angiotensin (Ang)II type 1 receptor antagonists or diuretics. Plasma renin activity (PRA), serum ACE activity, plasma AngI, AngII and aldosterone concentrations, and blood pressure were measured before and 6 months after the start of the study.

RESULTS

No significant changes in PRA, ACE activity, or the AngI, AngII or aldosterone levels were observed in any of the groups. In all the groups, blood pressure remained unchanged.

CONCLUSION

Raloxifene may have no significant effect on the RAAS or blood pressure in hypertensive and normotensive osteoporotic postmenopausal women.

Hormone replacement therapy and arterial blood pressure in postmenopausal women with hypertension

BACKGROUND

Data on the effect of hormone replacement therapy (HRT) on blood pressure (BP) in hypertensive menopausal women are limited.

OBJECTIVE

To investigate the association between HRT and longitudinal change in BP in hypertensive menopausal women.

PATIENTS AND METHODS

We recruited a total of 161 hypertensive menopausal women (mean age = 52.2 +/- 6.6 years) attending the hypertension clinic in our hospital that requires HRT to attenuate the effect of menopause symptoms. These women were followed for up tp 36 months, being evaluated every 6 months with measurements of their BP, weight and the number of drugs needed to control their BP. We also measured serum cholesterol levels before and after the initiation of HRT.

RESULTS

The systolic BP remained unaffected throughout the whole follow-up period, whereas the diastolic BP was slightly reduced at 6, 24 and 36 months. This decrease was accompanied by an increased need for antihypertensive medication throughout the entire follow-up period, while the body weight also increased at 18, 24, and 36 months. No particular differences were noted with respect to ethnicity, history of pre-eclampsia or surgical menopause, before and after the initiation of HRT. Serum cholesterol levels remained unchanged during the evaluation period. Oestrogen-progestogen combination therapy use was associated with a lower diastolic BP and a smaller number of antihypertensive drugs compared to other forms of HRT.

CONCLUSION

HRT use does not have an adverse gross effect on BP in hypertensive menopausal women who need it, although there may be an increased need for antihypertensive therapy during the 36-moth follow-up period of our study.

Newly developed angiotensin II-infused experimental models in vascular biology

Angiotensin II is a major vasoactive peptide in the renin-angiotensin system (RAS). In vitro evidence demonstrates that this peptide can modulate the function of various adhesion molecules, chemokines, cytokines and growth factors, and ultimately contributes to cell proliferation, hypertrophy and inflammation. Moreover, in vivo studies further support that angiotensin II induces several vascular alterations including sustained elevations of blood pressure, enhanced inflammatory response, increased medial thickness of the aortas, and formation of aortic dissection and aneurysms. Thus, it has been a long time that angiotensin II-induced hypertension, atherosclerosis and abdominal aortic aneurysms emerge as important experimental models with respect to vascular biology. Applications of these models to investigate the vascular diseases have dramatically improved our understanding in the pathogenesis of these diseases. However, the pathophysiology of angiotensin II in vivo remains to be determined in many other vascular diseases where angiotensin II has been implicated as the detrimental factor, at least in part due to the limit availability of animal models. Recently some new exciting experimental models based on angiotensin II infusion have been reported to replicate the human diseases, such as postmenopausal hypertension, preeclampsia, vascular remodeling, vascular aging and neovascularization. In this review, we will focus on the rationales and anticipated applications of these newly developed models, with special emphasis placed on those relevant to the vascular biology. We will also discuss the limitations of the method of chronic angiotensin II infusion and additional approaches to overcome these limitations. These experimental models will provide great opportunity for us to investigate the molecular mechanisms of angiotensin II and evaluate therapeutic approaches, particularly to finely tune the potential role of RAS activation in various vascular events using genetically engineered mice.

Angiotensin II induces vascular dysfunction without exacerbating blood pressure elevation in a mouse model of menopause-associated hypertension

BACKGROUND

Follitropin-receptor knockout (FORKO) mice are estrogen-deficient, hyperandrogenic and exhibit features of menopause and elevated blood pressure (BP). Because the renin-angiotensin system has been implicated in menopause-associated hypertension, we questioned whether angiotensin II (Ang II) challenge would further increase BP in FORKO mice and whether this is associated with cardiovascular remodeling and inflammation.

RESULTS

Ang II (400 ng/kg per min) increased BP, assessed by radiotelemetry, similarly in female FORKO and wild-type (WT) mice. Acetylcholine-induced vasodilation was attenuated and Ang II-induced contraction was enhanced in FORKO mice (P < 0.05). This was associated with increased expression of vascular Ang type 1 receptors (AT1R) and estrogen receptor alpha (ERalpha). Vascular structure (media/lumen ratio) was similar in both groups. Abundance of gp91, nitrotyrosine formation and superoxide production, indices of inflammation and cardiac collagen content were increased in Ang II-treated FORKO compared to Ang II-treated WT mice (P < 0.05).

CONCLUSIONS

Thus, in FORKO mice Ang II exacerbates endothelial dysfunction, augments contractility, increases oxidative stress, and promotes cardiac fibrosis without worsening vascular remodeling or BP elevation compared to Ang II-treated WT controls. Our findings suggest that in FORKO mice Ang II may be more important in influencing vascular tone and endothelial function, possibly through oxidative stress and altered ERalpha signaling, than in arterial remodeling and BP elevation.

Estradiol Induces Discordant Angiotensin and Blood Pressure Responses to Orthostasis in Healthy Postmenopausal Women

Postmenopausal estrogen replacement therapy (ERT) is reported to increase angiotensin II under resting conditions. To determine the implications of this increase for cardiovascular regulation during simulated orthostasis, blood pressure (BP), heart rate (HR), renin, angiotensinogen, angiotensin II, and aldosterone were measured at rest and during lower body negative pressure (LBNP; −10, −20, and −40 mm Hg). We studied 13 normotensive postmenopausal women (54±2 [mean±SE] years) before and after 1 month of oral estradiol 2 mg daily, and 14 premenopausal women. LBNP activated the renin-angiotensin system acutely in premenopausal but not postmenopausal women. Resting renin and aldosterone were unaffected by estradiol, whereas angiotensinogen ( P <0.001) and angiotensin II ( P <0.01) increased. Renin, aldosterone, and HR responses to LBNP (which tended to be less in postmenopausal women [ P =0.06]) were not affected by estradiol. Importantly, angiotensin II was higher on estradiol during all stages of LBNP, and increased 70% above resting values at the end of this stimulus ( P <0.05), yet BP was significantly lower, both at rest ( P <0.05) and during LBNP ( P <0.01). In summary, in normotensive postmenopausal women, estradiol increases angiotensin II, but not aldosterone, at rest and during orthostatic stress, yet lowers, rather than raises, BP under both conditions. Downregulation of vascular and adrenal responsiveness to angiotensin II may protect healthy women against this activation. Loss of such protection may elevate BP and have adverse implications for women with conditions that impair their capacity to counteract the pathological actions of angiotensin II. This may contribute to higher cardiovascular event rates reported in recent ERT trials.

Ambulatory blood pressure monitoring and active renin in menopausal women treated with amlodipine and hormone replacement therapy

The aim of this study was to follow up the effect of an 8-week treatment with amlodipine given alone or in combination with hormone replacement therapy (HRT) on blood pressure and active renin in postmenopausal women with mild to moderate arterial hypertension using both conventional clinical blood pressure measurements and ambulatory blood pressure monitoring. Twenty-nine hypertensive menopausal women were divided randomly into two groups according to the treatment regimens: amlodipine and amlodipine plus HRT. The combination with HRT led to normalization of 24-h and daytime systolic and diastolic blood pressure. In contrast to the group treated with amlodipine alone, where a significant fall only of systolic night-time blood pressure was observed, in the group treated with amlodipine plus HRT both systolic and diastolic night-time blood pressure decreased significantly. Active renin did not change significantly after treatment in both groups. Triglycerides decreased significantly and high-density lipoprotein-cholesterol increased significantly only after amlodipine treatment. There were no significant differences in serum total cholesterol and low-density lipoprotein-cholesterol after HRT plus amlodipine. In conclusion, amlodipine is effective in reducing blood pressure in postmenopausal women. The maintenance of a normal circadian blood pressure pattern was influenced by HRT.

Effects of conjugated oestrogen and droloxifene on the renin-angiotensin system, blood pressure and renal blood flow in postmenopausal women

OBJECTIVE

The aim of this study was to evaluate the effect of conjugated equine oestrogen (CEE), and droloxifene, a selective oestrogen receptor modulator (SERM) on individual components of renin-angiotensin-aldosterone (RAAS) and blood pressure (BP) in postmenopausal women.

DESIGN AND PATIENTS

Twenty-one normotensive (NT) and 10 hypertensive (HT) postmenopausal women received either CEE (0.625 mg/day) or droloxifene (60 mg/day) for 6 weeks and, after a 4-week washout, were restudied on the alternate medication.

MEASUREMENTS

Hormones of the RAAS and supine BP were measured prior to and at the end of each drug treatment in all subjects. In a subgroup of the NT (n = 10), 24 h ambulatory BP was performed and renal blood flow was determined by PAH clearance both basally and in response to 45-min angiotensin II (Ang II) infusion (3 ng/kg/min).

RESULTS

CEE significantly increased angiotensinogen, decreased active renin and angiotensin-converting enzyme (ACE), and maintained plasma immunoreactive (ir) angiotensin I (Ang I) levels compared to baseline. With droloxifene, angiotensinogen, active renin and Ang I remained unchanged. Both CEE and droloxifene significantly increased plasma ir-Ang II levels (pmol/l) in NT (baseline: 25.7 +/- 2.5, CEE: 36.6 +/- 3.4, droloxifene: 33.3 +/- 3.1, P < 0.002) and HT women (baseline: 17.9 +/- 2.3, CEE: 27.9 +/- 3.2, droloxifene: 25.9 +/- 4.9, P < 0.005). Renal blood flow was lower on CEE (P = 0.02) compared with baseline. Systemic BP (supine and 24-h ambulatory) was unchanged during both treatments.

CONCLUSION

This study demonstrates higher circulating levels of ir-Ang II with CEE and droloxifene.

Attenuated responses to angiotensin II in follitropin receptor knockout mice, a model of menopause-associated hypertension

Activation of the renin-angiotensin system has been implicated in the development of hypertension in menopausal women. We investigated whether blood pressure is elevated and whether angiotensin II (Ang II)-induced vascular reactivity is increased in follitropin receptor knockout (FORKO) female mice. These mice are estrogen-deficient and have characteristics similar to postmenopausal women. Serum estradiol levels were significantly reduced in FORKO versus wild-type mice (1.4+/-0.2 versus 15+/-3 pg/mL, P<0.01). Blood pressure, measured by telemetry, was significantly increased in FORKO (120+/-2/92+/-2 mm Hg) compared with wild-type counterparts (110+/-1/85+/-2 mm Hg, P<0.05). Vascular dose responses to acetylcholine (endothelium-dependent dilation) and sodium nitroprusside (endothelium-independent dilation) were not different. Ang II-induced vasoconstriction was blunted in FORKO compared with wild-type mice (P<0.05). Media-to-lumen ratio was significantly increased in FORKO (6.2+/-0.5%) versus control mice (5.2+/-0.3%), indicating vascular remodeling. Aortic*O2- levels, NADH-inducible.O2- generation, and plasma levels of thiobarbituric acid reactive substances (TBARS), indexes of oxidative stress, were not significantly different between wild-type and FORKO mice. Vascular AT1 receptor content, assessed by immunoblotting, was reduced by 40% in FORKO compared with wild-type mice (P<0.01). This was associated with decreased circulating Ang II levels in FORKO versus control mice. These data indicate that FORKO mice have increased blood pressure, vascular remodeling, and attenuated vascular responses to Ang II. Our findings suggest that vascular Ang II signaling is downregulated in female FORKO mice and that Ang II may not play an important role in blood pressure elevation in this model of menopause-associated hypertension.

Hormone replacement therapy causes a decrease in hepatocyte growth factor in hypertensive women

OBJECTIVE

Serum hepatocyte growth factor (HGF) is associated with blood pressure. We investigated whether the serum HGF level differs between hypertensive and normotensive postmenopausal women (PMW) and whether hormone replacement therapy (HRT) alters the serum HGF level and blood pressure in hypertensive and normotensive PMW.

DESIGN

Prospective observational study.

METHODS

A total of 33 PMW with mild to moderate essential hypertension controlled by antihypertensive treatment (mean age, 57 +/- 6 years) and 23 normotensive PMW (mean age, 57 +/- 7 years) received continuous HRT (0.625 mg of conjugated equine estrogen combined with 2.5 mg of medroxyprogesterone acetate) once a day orally for 12 months, and we measured serum HGF levels and blood pressure before and 12 months after the start of HRT.

RESULTS

The baseline serum HGF level was significantly higher in hypertensive PMW than in normotensive PMW. HRT significantly decreased the serum HGF level in hypertensive subjects, from 2.85 +/- 0.64 pmol/l to 2.49 +/- 0.65 pmol/l (P < 0.001), but not in normotensive subjects. HRT did not change blood pressure in either group.

CONCLUSIONS

Serum HGF level before the start of HRT was higher in the hypertensive PMW than in the normotensive PMW. Furthermore, HRT decreases serum HGF without decreasing blood pressure in hypertensive PMW. The HRT-induced decrease in serum HGF was greater in hypertensive PMW than in normotensive PMW, and the decrease was independent of blood pressure changes.

Effects of hormone replacement therapy on office and ambulatory blood pressure in Japanese hypertensive postmenopausal women

No study has demonstrated that hormone replacement therapy (HRT) affects blood pressure (BP) measured by 24-h ambulatory blood pressure monitoring (ABPM) in Japanese postmenopausal women (PMW) with normotension or mild-to-moderate essential hypertension. In the present study, we examined the effects of HRT on office BP and 24-h ambulatory blood pressure (ABP) in Japanese hypertensive or normotensive PMW. Thirty-one hypertensive (HT-HRT group) and 17 normotensive PMW (NT-HRT group) received HRT (0.625 mg of conjugated equine estrogen combined with 2.5 mg of medroxyprogesterone acetate) orally for 12 months, and 30 hypertensive (HT-Control group) and 19 normotensive PMW (NT-Control group) did not receive HRT. In all of the hypertensive PMW, BP was controlled by a variety of antihypertensive drugs before starting HRT. The hypertensive PMW were divided into two groups according to the results of ABP before HRT: nondippers (those without a diurnal change in BP) and dippers (those with a diurnal change in BP). In all patients, office BP measurements and 24-h ABPM were performed before and 12 months after the start of HRT. HRT did not change either the office or the 24-h ambulatory systolic, diastolic, or mean BP in any of the groups. Therefore, HRT did not significantly alter the proportion of nondippers. We conclude that with respect to BP, HRT might not be harmful in hypertensive PMW whose BP has been well-controlled prior to the initiation of HRT, as well as in normotensive PMW.

Effects of hormone replacement therapy on serum angiotensin-converting enzyme activity and plasma bradykinin in postmenopausal women according to angiotensin-converting enzyme-genotype

An insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene determines serum ACE levels. The D allele is associated with increased ACE activity and is linked to cardiovascular disease. Hormone replacement therapy (HRT) in postmenopausal women (PMW) decreases serum ACE activity and concomitantly increases plasma bradykinin. We investigated the effect of HRT on these parameters in PMW according to ACE-genotype. We assessed 68 PMW during 12-month oral HRT (0.625 mg conjugated estrogen +2.5 mg medroxyprogesterone acetate). ACE genotype was determined at baseline, and serum ACE activity and plasma bradykinin were measured at baseline and after 3-, 6-, and 12-month HRT. We divided the PMW into three groups according to ACE genotype: groups I/I (n = 26), I/D (n = 33), and D/D (n = 9). HRT resulted in a significant reduction in the genotype-associated increase in ACE activity in the ACE I/D and D/D groups after 6-month (p < 0.001 and p < 0.05, respectively) and 12-month HRT (p < 0.001 and p < 0.01, respectively), but not in the I/I group. While the reduction of ACE activity was expected to increase bradykinin in the ACE I/D and D/D groups, HRT significantly increased the bradykinin levels not only in these two groups but also in the ACE I/I group at both 6 months (p < 0.01, p < 0.05, and p < 0.001, respectively) and 12 months after the start of HRT (p < 0.01, p < 0.01, and p < 0.01, respectively). These results suggest that the increased plasma bradykinin of PMW by HRT might not be induced solely by the reduction in serum ACE activity.

Effects of age, hypertension and HRT on serum aminopeptidase A activity

OBJECTIVES

It is conceivable that aminopeptidase A (APA)/angiotensinase is involved in the pathogenesis of hypertension. The aim of this study was to evaluate the influences of age, hypertension and hormone replacement therapy (HRT) on serum APA activity in middle-aged and elderly women.

METHODS

Blood samples were collected from 117 women aged 40-69, 48 normotensive healthy women not receiving HRT, 57 normotensive women receiving HRT, and 12 hypertensive women (blood pressure >140/90 mmHg) with no medication. Serum APA activity was measured using alpha-glutamyl-p-nitroanilide as substrate spectrophotometrically.

RESULTS

Serum APA activity increased along with age between 40 and 69 in healthy women not taking HRT (r=0.351, P<0.05). Hypertensive women had higher serum APA activity than age-matched normotensive women (25.4+/-4.2 versus 22.4+/-3.4 microM/min; P<0.05) Compared with non-users of HRT, APA activity was elevated in women receiving HRT (23.9+/-3.8 versus 20.4+/-3.2 microM/min; P<0.05).

CONCLUSIONS

APA activity had a positive correlation with age in healthy women. Furthermore, hypertension and HRT up-regulated the serum APA activity significantly. The measurements of serum APA would be of value to elucidate the physiological and clinical roles of APA, although further studies are required.

ACE genotype and ACE inhibitor response in kidney disease: a perspective

Angiotensin-converting enzyme (ACE) inhibitors have been shown to reduce blood pressure and slow the progression of renal diseases. However, a substantial interindividual variability in treatment response also has been noted. The activity of ACE is partially dependent on the presence or absence of a 287-bp element in intron 16, and this insertion/deletion (I/D) polymorphism accounts for 47% of the total phenotypic variance in plasma ACE; DD subjects have the highest; ID subjects, intermediate; and II individuals, the lowest concentrations. Data suggest that genotype also determines tissue enzyme activity, and, at least under certain conditions, ACE activity is a rate-limiting step for angiotensin II formation. It therefore has been speculated that the ACE polymorphism also might affect therapeutic effects of ACE inhibitors. Unfortunately, clinical studies performed to date do not allow us to draw definite conclusions. Nonetheless, the rapidly evolving area of pharmacogenomics soon will also affect therapeutic decisions in the field of nephrology and hypertension.

Effects of hormone replacement therapy on left ventricular hypertrophy and growth-promoting factors in hypertensive postmenopausal women

We investigated the effects of hormone replacement therapy (HRT) on left ventricular hypertrophy (LVH) and growth-promoting factors in hypertensive postmenopausal women (PMW) with LVH. Twenty-one Japanese hypertensive PMW (age 55.3+/-0.8 years) with LVH who had never received HRT volunteered to participate in this study. Eleven subjects received a daily dose of HRT (0.625 mg conjugated equine estrogen, 2.5 mg medroxyprogesterone acetate) orally for 12 months. Ten PMW who refused HRT were enrolled as controls. Blood pressure and serum angiotensin-converting enzyme (ACE) activity, plasma aldosterone, and insulin resistance were measured. M-mode echocardiography and blood pressure measurements were performed in all patients. Data obtained before and after 12 months of HRT were compared. No significant differences in blood pressure were observed between the two groups after 12 months of HRT. In the HRT group, the LV mass index (p<0.01), serum ACE activity (p<0.01), and plasma aldosterone (p<0.01) levels were reduced after 12 months of treatment. The changes in serum ACE activity and plasma aldosterone were not correlated with the change in LV mass index in the HRT group. No significant changes in blood pressure, LV mass index, serum ACE activity, plasma aldosterone, or insulin resistance were observed in the control group. HRT contributed to the reduction of LV mass in hypertensive PMW. However, the effect of HRT on LVH did not appear to be associated with changes in growth-promoting factors, such as blood pressure, serum ACE activity, plasma aldosterone, and insulin resistance.

Hormone replacement therapy and hypertension

Hypertension, particularly systolic hypertension, affects postmenopausal women and is an important risk factor for cardiovascular disease in this group. In the last year, several papers have better defined the mechanisms by which hormone replacement therapy influences blood pressure in postmenopausal women, including effects on nitric oxide, angiotensin II and vascular stiffness (compliance). Currently, data concerning the influence of hormone replacement therapy on blood pressure in postmenopausal women are inconclusive because of the limitations of published studies. It is clear, however, that hypertension is not a contraindication to starting hormone replacement therapy.

Comparative effects of estrogen and angiotensin-converting enzyme inhibition on plasminogen activator inhibitor-1 in healthy postmenopausal women

BACKGROUND

This study compares the effect of estrogens and ACE inhibition on plasminogen activator inhibitor-1 (PAI-1) concentrations in healthy postmenopausal women, genotyped for a 4G/5G polymorphism in the PAI-1 promoter, a polymorphism shown to influence PAI-1 concentrations. Methods and Results- Morning estradiol, PAI-1, tissue plasminogen activator, plasma renin activity, angiotensin II, and aldosterone were measured in 19 postmenopausal women (5G/5G:4G/5G:4G4G=5:10:4, respectively) at baseline and during randomized, single-blind, crossover treatment with conjugated equine estrogens 0.625 mg per os per day, ramipril 10 mg per os per day, and combination estrogens and ramipril. Estradiol (P<0.005) and angiotensin II (P<0.01) were significantly higher during estrogens. Plasma renin activity was significantly increased during ACE inhibition (P<0.05). Both conjugated estrogens [PAI-1 antigen from 12.5 (7.6, 17.4) [mean (95% CI)] baseline to 6.6 (2.6, 10.7) ng/mL, P<0.01] and ACE inhibition [8.3 (4.9, 11.7) ng/mL, P<0.005] decreased PAI-1 without decreasing tissue plasminogen activator. The effect of combined therapy on PAI-1 [5.6 (2.3, 8.8) ng/mL] was significantly greater than that of ramipril alone (P<0.05). There was a significant effect of PAI-1 4G/5G genotype on baseline PAI-1 concentrations (P=0.001) and a significant interactive effect of 4G/5G genotype and treatment, such that genotype influenced the change in PAI-1 during ramipril (P=0.011) or combined therapy (P=0.006) but not during estrogens (P=0.715).

CONCLUSIONS

ACE inhibition with ramipril and conjugated estrogens similarly decrease PAI-1 antigen concentrations in postmenopausal women. Larger studies that use clinical outcomes are needed to determine whether PAI-1 4G/5G genotype should influence the choice of conjugated estrogens or ACE inhibition for the treatment of healthy postmenopausal women.