Gender dimorphism in cardiac adaptation to hypertension is unveiled by prior treatment and efficacy

Prognostic Implication of Longitudinal Changes in Cardiothoracic Ratio and Aortic Arch Calcification in Hemodialysis Patients

Patients with end-stage renal disease have a high prevalence of cardiovascular disease. Chest radiography can be used to assess cardiothoracic ratio (CTR) and aortic arch calcification (AoAC). The aims of this longitudinal follow-up study were to investigate factors associated with changes in CTR and AoAC and understand whether these changes are associated with overall and cardiovascular mortality in hemodialysis (HD) patients. We enrolled 260 patients undergoing HD who had at least two available chest X-rays from 2008 to 2015. CTR and AoAC were assessed in each patient using measurements from baseline and annual chest X-rays. The CTR increased from 49.05% to 51.86% and the AoAC score increased from 3.84 to 9.73 over 7 years. The estimated slopes were 0.24 (p < 0.0001) for CTR and 0.08 (p = 0.0441) for AoAC. Increased AoAC, older age, female sex, coronary artery disease, and decreased albumin were associated with an increase in CTR, and older age, cerebrovascular disease, decreased albumin, increased Kt/V, and the use of antiplatelet agents were associated with an increase in AoAC. During follow-up, 136 of the 260 (52.3%) patients died, of whom 72 died due to cardiovascular causes. The change in CTR was greater in those who died (p = 0.0125) than in those who survived. The AoAC score was also higher in those who died than in those who survived, although there was no significant difference in the change in AoAC between the two groups (p = 0.8035). CTR and AoAC increased significantly over time in the HD patients in this longitudinal follow-up study, and the change in CTR was greater in those who died than in those who survived. Chest radiography is a simple and useful tool to assess the progression of CTR and AoAC as a prognostic marker.

The Role of 17β-Estradiol in Myocardial Hypertrophy in Females in the Presence and Absence of Hypertension

PURPOSE

There are gender-differences in the development of cardiac hypertrophy, which appear to be related, in part, to sex hormones. This report gives an overview of this relationship and reports on original data assessing how varying levels of plasma 17β-estradiol determine relative heart size, in vivo function, in hypertensive versus normotensive rats.

METHODS

Female spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats were either surgically neutered or sham operated at 21 days of age. A subgroup of neutered females received 17β-estradiol replacement. At 6 months, in vivo heart function was measured, the heart/body weight ratio (mg/g) was assessed as a measure of hypertrophy and correlated with plasma 17β-estradiol.

RESULTS

There was a significant positive relationship between plasma 17β-estradiol and heart/body weight ratio in both WKY (R = 0.509, P = 0.011) and SHR females (R = 0.359, P = 0.032). Interestingly, the slope of this relationship was 2-fold steeper in the WKY females, suggesting a blunted effect in the SHR, whose hearts also had 35 % lower ERβ content. With increasing plasma estradiol levels, WKY females showed improved LV function while SHR females showed impaired LV relaxation.

CONCLUSIONS

Plasma estradiol modulates relative heart mass in both normotensive and hypertensive female rats. With any increase in plasma 17β-estradiol, hypertensive females show a blunted response compared with the normotensive females, which may be related to a reduced estrogen receptor expression in the presence of hypertension. In contrast to normotensive females, hypertensive females showed impaired function with increases in plasma 17β-estradiol.

Arterial stiffness and vascular complications in patients with type 1 diabetes: the Finnish Diabetic Nephropathy (FinnDiane) Study

INTRODUCTION/AIMS

While patients with type 1 diabetes (T1D) are known to suffer from early cardiovascular disease (CVD), we examined associations between arterial stiffness and diabetic complications in a large patient group with T1D.

METHODS

This study included 807 subjects (622 T1D and 185 healthy volunteers (age 40.6 ± 0.7 versus 41.6 ± 1.2 years; P = NS)). Arterial stiffness was measured by pulse wave analysis from each participant. Furthermore, information on diabetic retinopathy, nephropathy, and CVD was collected. The renal status was verified from at least two out of three urine collections.

RESULTS

Patients with T1D without signs of diabetic nephropathy had stiffer arteries measured as the augmentation index (AIx) than age-matched control subjects (17.3% ± 0.6% versus 10.0% ± 1.2%; P < 0.001). Moreover, AIx (OR 1.08; 95% CI 1.03-1.13; P = 0.002) was associated with diabetic laser-treated retinopathy in patients with normoalbuminuria in a multivariate logistic regression analysis. The same was true for AIx and diabetic nephropathy (1.04 (1.01-1.08); P = 0.004) as well as AIx and CVD (1.06 (1.00-1.12); P = 0.01) in patients with T1D.

CONCLUSIONS

Arterial stiffness was associated with microvascular and macrovascular complications in patients with T1D.

Disorders of orthostatic blood pressure response are associated with cardiovascular disease and target organ damage in hypertensive patients

BACKGROUND

The prevalence and clinical significance of orthostatic hypertension (OHT) remain largely undetermined in hypertensive patients. This study investigated the association of OHT and orthostatic hypotension (OH) with cardiovascular disease (CVD) and target organ damage (TOD) in hypertensive patients.

METHODS

A cross-sectional study was conducted in 4,711 hypertensives and 826 normotensives, aged 40-75 years. OHT was defined as an increase in systolic blood pressure (SBP) of > or =20 mm Hg, and OH was defined as either a reduction in SBP of at least 20 mm Hg or a reduction in diastolic BP (DBP) of at least 10 mm Hg during the first 3 min after standing.

RESULTS

Hypertension was only independently associated with a risk of OHT. After controlling for age, sex, and other confounders, OH was associated with peripheral artery disease (PAD) (odds ratio (OR) 1.49, 95% confidence interval (CI) 1.15-1.89, P < 0.01), left ventricular hypertrophy (LVH) (OR 1.48, 95% CI 1.12-1.93, P < 0.001), coronary artery disease (CAD) (OR 1.71, 95% CI 1.12-2.61, P < 0.01), and stroke (OR 1.72, 95% CI 1.19-2.34, P < 0.01), but OHT was only associated with PAD (OR 1.36, 95% CI 1.05-1.81, P < 0.05) and stroke (OR 1.76, 95% CI 1.27-2.26, P < 0.01). The adjusted OR for PAD, predicted by the quintiles of the orthostatic SBP changes, showed a J-shaped relationship in untreated hypertensive patients, as was also the case for LVH in hypertensive women.

CONCLUSIONS

OH is associated with CV risk; the associations of OHT with TOD and stroke in hypertensive patients still need to be confirmed in prospective studies.

Sex modifies exercise and cardiac adaptation in mice

How an individual's sex and genetic background modify cardiac adaptation to increased workload is a topic of great interest. We systematically evaluated morphological and physiological cardiac adaptation in response to voluntary and forced exercise. We found that sex/gender is a dominant factor in exercise performance (in two exercise paradigms and two mouse strains) and that females of one of these strains have greater capacity to increase their cardiac mass in response to similar amounts of exercise. To explore the biochemical mechanisms for these differences, we examined signaling pathways previously implicated in cardiac hypertrophy. Ca2+/calmodulin-dependent protein kinase (CaMK) activity was significantly greater in males compared with females and increased after voluntary cage-wheel exposure in both sexes, but the proportional increase in CaMK activity was twofold higher in females compared with males. Phosphorylation of glycogen synthase kinase-3beta (GSK-3beta) was evident after 7 days of cage-wheel exposure in both sexes and remained elevated in females only by 21 days of exercise. Despite moderate increases in myocyte enhancer factor-2 (a downstream effector of CaMK) transcriptional activity and phosphorylation of Akt with exercise, there were no sex differences. Mitogen-activated protein kinase signaling components (p38 mitogen-activated protein kinase and extracellular regulated kinase 1/2) were not different between male and female mice and were not affected by exercise. We conclude that females have increased exercise capacity and increased hypertrophic response to exercise. We have also identified sex-specific differences in hypertrophic signaling within the cardiac myocyte that may contribute to sexual dimorphism in exercise and cardiac adaptation to exercise.

Gender-differences in myocardial adaptation to afterload in normotensive and hypertensive rats

Echocardiographic studies suggest that women appear to exhibit a greater degree of myocardial hypertrophy in response to increased afterload than men. Therefore, gender differences and the role of estrogen and testosterone in the development of myocardial hypertrophy were studied in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. Male and female rats were either surgically neutered or underwent a sham operation at 21 days of age. A subgroup of neutered females of each strain received 17beta-estradiol replacement. At 6 months, the heart weight-to-body weight ratio was assessed and correlated with systemic blood pressure. Compared with males, females had significantly smaller body and heart weights in both normotensive and hypertensive strains. Despite this, females consistently had significantly greater heart weight-to-body weight ratios. In females, neutering significantly lowered the heart weight-to-body weight ratio in WKY rats, which was returned to intact levels with estrogen replacement. Female SHR showed similar, but not statistically significant, responses. In males, neutering appeared to result in a higher heart weight-to-body weight ratio in WKY rats, but the opposite was seen in SHR. In addition, there was a significant correlation between arterial blood pressure and heart weight-to-body weight ratio (systolic r=0.45, P=0.0015: diastolic r=0.52, P=0.0002) in intact males and females of both strains, and for a given diastolic pressure, females always exhibited a greater heart weight-to-body weight ratio than males. Thus, a greater degree of myocardial hypertrophy in females appears to be related to the presence of estrogen in both normotensive and hypertensive rats. Females show a stronger relationship between heart/body weight and blood pressure than males, which occurred independent of the presence of estrogen.

Impact of ethnicity on left ventricular mass and relative wall thickness in essential hypertension

This study was designed to evaluate the impact of ethnicity on left ventricular (LV) mass, and relative wall thickness in 527 patients (57% men, mean age 60 +/- 7 years) with mild to moderate high blood pressure. There were 63% Caucasians, 21% African-Americans, and 16% Hispanics. LV mass was indexed according to body surface area, height, and height to the allometric power of 2.7. Relative wall thickness included the 4 widely recognized patterns: normal, concentric remodeling, eccentric hypertrophy, and concentric hypertrophy. LV mass indexed to body surface area was similar among all 3 ethnic groups (Caucasians 117.1 g/m2, African-Americans 119.2 g/m2, Hispanics 122.7 g/m2); however, when indexed to height and height to the power of 2.7, Hispanics had slightly larger masses than the other 2 groups (Hispanics 168.1 and 73.3 g/m2.7 vs Caucasians 159.8 and 64.4 g/m2.7 [p = NS and p < 0.005]; and vs African-Americans 164.8 and 69.2 g/m2.7 [p = NS for both]). Using body surface area, the concentric remodeling was the predominant form of cardiac adaptation in Caucasians (36%) and African-Americans (42%), whereas the concentric hypertrophy pattern was 38% in Hispanics. Using indexing for both height and height to the power of 2.7, the concentric hypertrophy pattern predominated in all 3 ethnic groups (Caucasians 48% and 51%; African-Americans 68% and 66%; Hispanics 59% and 65%). In conclusion, because of the independent impact of weight on high blood pressure, LV mass adjusted to height or to height at the power of 2.7 should be reported in population studies. The concentric hypertrophy pattern--classic LV response to pressure overload conditions--is better represented when LV mass is indexed to height or to height to the allometric power of 2.7 than to body surface area.

Comparison of left ventricular mass and geometric remodeling in treated and untreated men and women >50 years of age with systemic hypertension

To investigate the effects of left ventricular (LV) mass and geometry in hypertensive patients >50 years of age, 540 men and women were divided into controlled, uncontrolled, and untreated groups. The high prevalence of concentric LV hypertrophy in postmenopausal women, despite medical therapy, emerged as a potentially important and underrecognized factor of their cardiovascular risk.