Hormone replacement therapy does not affect 24-h ambulatory blood pressure in healthy non-smoking postmenopausal women

A clinical set-up for noninvasive blood pressure monitoring using two photoplethysmograms and based on convolutional neural networks

Blood pressure is a reliable indicator of many cardiac arrhythmias and rheological problems. This study proposes a clinical set-up using conventional monitoring systems to estimate systolic and diastolic blood pressures continuously based on two photoplethysmogram signals (PPG) taken from the earlobe and toe. Several amendments were applied to conventional clinical monitoring devices to construct our project plan. We used two monitors to acquire two PPGs, one ECG, and invasive blood pressure as the reference to evaluate the estimation accuracy. One of the most critical requirements was the synchronization of the acquired signals that was accomplished by using ECG as the time reference. Following data acquisition and preparation procedures, the performance of each PPG signal alone and together was investigated using deep convolutional neural networks. The proposed architecture was evaluated on 32 records acquired from 14 patients after cardiovascular surgery. The results showed a better performance for toe PPG in comparison with earlobe PPG. Moreover, they indicated the algorithm accuracy improves if both signals are applied together to the network. According to the British Hypertension Society standards, the results achieved grade A for both blood pressure measurements. The mean and standard deviation of estimation errors were +0.3 ± 4.9 and +0.1 ± 3.2 mmHg for systolic and diastolic BPs, respectively. Since the method is based on conventional monitoring equipment and provides a high estimation consistency, it can be considered as a possible alternative for inconvenient invasive BP monitoring in clinical environments.

Aerobic training abolishes ambulatory blood pressure increase induced by estrogen therapy: a double blind randomized clinical trial

Emerging data reveal that oral estrogen therapy can increase clinic blood pressure (BP) in post-menopausal women; however, it is important to establish its effects on ambulatory BP, which is a better predictor for target-organ damage. Besides estrogen therapy, aerobic training is widely recommended for post-menopausal women, and it can decrease ambulatory BP levels. This study was designed to evaluate the effect of aerobic training and estrogen therapy on the ambulatory BP of post-menopausal women. Forty seven healthy hysterectomized women were randomly divided (in a double-blind manner) into 4 groups: placebo-control (PLA-CO=12), estrogen therapy-control (ET-CO=14), placebo-aerobic training (PLA-AT=12), and estrogen therapy-aerobic training (ET-AT=09). The ET groups received estradiol valerate (1 mg/day) and the AT groups performed cycle ergometer, 3×/week at moderate intensity. Hormonal status (blood analysis), maximal cardiopulmonary exercise test (VO(2) peak) and ambulatory BP (24-h, daytime and nighttime) was evaluated before and 6 months after interventions. A significant increase in VO(2) peak was observed only in women who participated in aerobic training groups (+4.6±1.0 ml kg(-1) min(-1), P=0.00). Follicle-stimulating hormone was a significant decreased in the ET groups (-18.65±5.19 pg/ml, P=0.00), and it was accompanied by an increase in circulating estrogen (56.1±6.6 pg/ml). A significant increase was observed in the ET groups for daytime (P=0.01) and nighttime systolic BP (P=0.01), as well as nighttime diastolic BP (P=0.02). However, daytime diastolic BP was increased only in the ET-CO group (+3.4±1.2 mmHg, P=0.04), and did not change in any other groups. No significant effect was found in ambulatory heart rate. In conclusion, aerobic training abolished the increase of daytime ambulatory BP induced by estrogen therapy in hysterectomized, healthy, normotensive and postmenopausal women.

Burden of illness of hypertension among women using menopausal hormone therapy: a US perspective

OBJECTIVE

To estimate the burden of illness (BOI) of hypertension in a cohort of women receiving menopausal hormone therapy (HT).

METHODS

Patients with at least one prescription for menopausal HT were selected from the PharMetrics database during the period July 1, 2003, to June 30, 2005. Hormone therapy patients were divided into those with and without hypertension. The nonhypertensive cohort was propensity score-matched to the hypertensive cohort, controlling for patient demographics, overall comorbidities, and type of HT use. The BOI of hypertension in the menopausal HT cohort was defined as the difference in average annual total healthcare expenditures per person between the cohorts.

RESULTS

The prevalence of menopausal HT use was 9.75% among potentially eligible patients in this commercially insured sample. Hypertension was the most common comorbidity in the menopausal HT cohort, with a prevalence of 34%. Hormone therapy patients with hypertension (n = 106,729) had significantly higher average annual healthcare expenditures compared to matched HT patients without hypertension ($8908 vs. $5960 per person per year; difference of $2948; p < 0.001).

CONCLUSIONS

Hypertension is the most common comorbidity among menopausal HT users in the United States. The annual BOI of hypertension is both substantial and significant when compared to matched patients without hypertension, averaging $2948 per patient per year.

Baroreflex sensitivity varies during the rat estrous cycle: role of gonadal steroids

Baroreflex sensitivity (BRS) increases in women during the luteal phase of the menstrual cycle, when gonadal hormones are elevated, but whether a similar cycle-dependent variation in BRS occurs in rats is unknown. In addition, whether cyclic BRS changes depend on gonadal steroids has not been previously investigated. To test these hypotheses, BRS was determined in cycling female rats using two approaches: 1) baroreflex control of renal sympathetic nerve activity (RSNA) in anesthetized rats; 2) cardiovagal spontaneous BRS (sBRS) in conscious rats instrumented for continuous telemetric measurements of mean arterial pressure (MAP) and heart rate (HR). MAP, HR, and sBRS were also measured in rats 2-3 and 5-6 wk following ovariectomy (OVX), to eliminate gonadal steroids. In anesthetized rats, RSNA BRS gain was increased (P < 0.01) during proestrus (-4.8+/-0.5% control/mmHg) compared with diestrus/estrus (-2.8 +/- 0.3% control/mmHg). Similarly, a proestrous peak in sBRS was observed in conscious rats (1.66 +/- 0.07 ms/mmHg, proestrus; 1.48 +/- 0.06 ms/mmHg, diestrus/estrus; P < 0.001). OVX eliminated estrous cycle-induced variation in sBRS. In addition, OVX reduced (P < 0.05) diurnal variations in MAP (5.9 +/- 0.3 vs. 3.9 +/- 0.5 mmHg) and HR [54 +/- 4 vs. 39 +/- 3 beats per minute (bpm)], and abolished diurnal variations in sBRS. Finally, while MAP, HR, and sBRS were decreased 2-3 wk following OVX, approximately 3 wk later, MAP and sBRS increased, and HR decreased further. No changes in MAP, HR, or sBRS were seen with time in sham OVX controls. In summary, RSNA and cardiovagal sBRS vary during the rat estrous cycle, and this variation is abolished by OVX. We conclude that sex steroid hormones are required for both cyclic and diurnal changes in BRS in rats.

Meta-analysis: effect of hormone-replacement therapy on components of the metabolic syndrome in postmenopausal women

AIM

To quantify the effects of hormone-replacement therapy (HRT) on components of the metabolic syndrome in postmenopausal women.

METHODS

Comprehensive searches of electronic databases were performed from April 1966 to October 2004. We included randomized controlled trials that were of at least 8 weeks duration and evaluated the effect of HRT on metabolic, inflammatory or thrombotic components. Insulin resistance was calculated by homeostasis model assessment (HOMA-IR). Subgroup analysis evaluated the effects for transdermal and oral treatment and for diabetic and non-diabetic women.

RESULTS

Pooled results of 107 trials showed that HRT reduced abdominal fat [-6.8% (CI, -11.8 to -1.9%)], HOMA-IR [-12.9% (CI, -17.1 to -8.6%)] and new-onset diabetes [relative risk 0.7 (CI, 0.6-0.9)] in women without diabetes. In women with diabetes, HRT reduced fasting glucose [-11.5% (CI, -18.0 to -5.1%)] and HOMA-IR [-35.8% (CI, -51.7 to -19.8%)]. HRT also reduced low-density lipoprotein/high-density lipoprotein cholesterol ratio [-15.7% (CI, -18.0 to -13.5%)], lipoprotein(a) [Lp(a)] [-25.0% [CI, -32.9 to -17.1%)], mean blood pressure [-1.7% (CI, -2.9 to -0.5%)], E-selectin [-17.3% (CI, -22.4 to -12.1%)], fibrinogen [-5.5% (CI, -7.8 to -3.2%)] and plasminogen activator inhibitor-1 [-25.1% (CI, -33.6 to -15.5%)]. Oral agents produced larger beneficial effects than transdermal agents, but increased C-reactive protein (CRP) [37.6% (CI, 17.4-61.3%)] and decreased protein S [-8.6% CI, -13.1 to -4.1%)], while transdermal agents had no effect.

CONCLUSIONS

HRT reduces abdominal obesity, insulin resistance, new-onset diabetes, lipids, blood pressure, adhesion molecules and procoagulant factors in women without diabetes and reduced insulin resistance and fasting glucose in women with diabetes. Oral agents adversely affected CRP and protein S, while transdermal agents had no effects.

Effects of sex and estrogen on myosin COOH-terminal isoforms and contractility in rat aorta

We reported that estrogen treatment of ovariectomized rats increased uterine smooth muscle contractility and the ratio of the COOH-terminal myosin heavy chain isoform SM1 (204 kDa) and SM2 [200 kDa; Hewett TE, Martin AF, Paul RJ. J Physiol (Lond) 460: 351-364, 1993]. We extended this model to study sex and estrogen effects on vascular contractility. Experimental groups included 10- to 14-wk-old male (M), female (F), ovariectomized female (OF), and OF treated with estrogen (OF&E) for 7 days with a subcutaneous pellet delivery system, resulting in 17beta-estradiol of 85 (OF&E) vs. 5 (OF or M) pg/ml. The SM1-to-SM2 ratio increased from 1.8 to 2.6 in thoracic aorta, similar to uterine muscle. Isometric force was measured in 5-mm segments of intact and endothelium-denuded (-endo) aorta. With KCl, the maximum forces were in the order OF approximately M > OF&E, and ED50 OF&E > OF approximately M. Differences in ED50 with estrogen persisted after endothelial denudation. The decreased force in -endo OF aorta was not seen in OF&E, suggesting that estrogen altered an endothelium-dependent effect. No differences in maximum forces were noted with norepinephrine: ED50 OF > OF&E > M. Estrogen treatment, in contrast to KCl, increased sensitivity. Endothelial denudation increased sensitivity but reduced the differences between groups. With ACh relaxation, males were more sensitive than females, and estrogen had no effect. In the abdominal aorta, there were no changes in SM1/SM2 with 17beta-estradiol, and differences in contractility were blunted. In summary, estrogen treatment decreased responses to KCl but increased sensitivity to norepinephrine; male rats always demonstrated the highest contractility. An increase in the COOH-terminal myosin heavy chain isoform SM1-to-SM2 ratio with 17beta-estradiol treatment may underlie the changes observed in contractility.

Hormone replacement use, arterial distensibility, cardiac structure and circadian blood pressure profile in menopausal women

Observational and interventional studies that evaluate the impact of hormone replacement therapy (HRT) on cardiovascular changes have produced inconsistent and inconclusive results. The present study sought to elucidate the influence of HRT on aortic distensibility, left ventricular mass (LVM) and 24-h blood pressure (BP) profile in 38 menopausal women who were either HRT users or non-users. The two groups were similar for age, ambulatory BP, aortic distensibility, cardiac mass, lipid profile and body mass index but differed in clinic diastolic BP (DBP). HRT non-dippers had significantly lower clinic and daytime DBP and a smaller nocturnal BP reduction than dippers. Daytime DBP was significantly and inversely related to duration of HRT use. The present study demonstrates that hormonal therapy after menopause lowers DBP, but shows no significant influence on aortic distensibility, cardiac mass or 24-h BP profile. HRT users who were dippers demonstrated a significantly greater nocturnal BP reduction. Long-term controlled trails are needed to better define the effects of estrogen and progestin on the aorta, the heart and 24-h BP profile in normotensive and hypertensive menopausal women.

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.

Age-related reduction in estrogen receptor-mediated mechanisms of vascular relaxation in female spontaneously hypertensive rats

Hypertension increases with aging, and changes in vascular estrogen receptors (ERs) may play a role in age-related hypertension in women. We tested whether age-related increases in blood pressure in female spontaneously hypertensive rats (SHRs) are associated with reduction in amount and/or vascular relaxation effects of estrogen and ER. Arterial pressure and plasma estradiol were measured in adult (12 weeks) and aging (16 months) female SHRs, and thoracic aorta was isolated for measurement of active stress, 45Ca2+ influx, and ERs. Arterial pressure was greater and plasma estradiol was less in aging females than in adult females. In aorta of adult females, Western blots revealed alpha- and beta-ERs that were slightly reduced in aging rats. In endothelium-intact vascular strips, phenylephrine (Phe; 10(-5) mol/L) caused greater active stress in aging rats (9.3+/-0.2) than in adult rats (6.2+/-0.3x10(4) N/m2). 17beta-estradiol (E2) caused relaxation of Phe contraction and stimulation of vascular nitrite/nitrate production, which was reduced in aging rats. In endothelium-denuded strips, E2 still caused relaxation of Phe contraction, which was smaller in aging rats than adult rats. KCl (51 mmol/L), which stimulates Ca2+ influx, produced greater active stress in aging rats (9.1+/-0.3) than in adult rats (5.9+/-0.2x10(4) N/m2). E2 caused relaxation of KCl contraction and inhibition of Phe- and KCl-induced 45Ca2+ influx, which were reduced in aging rats. Thus, aging in female SHR is associated with reduction in ER-mediated NO production from endothelial cells and decrease in inhibitory effects of estrogen on Ca2+ entry mechanisms of smooth muscle contraction. The age-related decrease in ER-mediated vascular relaxation may explain the increased vascular contraction and arterial pressure associated with aging in females.