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Context: Urinary cadmium (Cd) excretion is associated with cancer and cardiovascular morbidity. A potential mechanism could be disturbance of steroidogenesis in gonads and adrenal glands., Objective: We tested whether urinary excretion of Cd is correlated with that of cortico- and sex steroid metabolites in the general adult population., Setting: The Swiss Kidney Project on Genes in Hypertension is a multicentric, family-based population study., Measures: Urinary excretions of steroid hormone metabolites and Cd were measured with separate day and night collections. Associations were analyzed by mixed linear models., Results: Urinary Cd and testosterone excretions in men were significantly correlated (respective day and night β values [standard error (SE)], 1.378 [0.242], P < 0.0005; and 1.440 [0.333], P < 0.0005), but not in women [0.333(0.257), P = 0.2; and 0.674 (0.361), P = 0.06]. Urinary Cd and cortisol excretions were positively associated in both sexes [day: β = 0.475 (SE, 0.157), P = 0.0025, and 0.877 (SE, 0.194), P < 0.0005, respectively; night: β = 0.875 (SE, 0.253), P < 0.0005 and 1.183 (SE, 0.277), P = 0.00002, respectively]. Cd excretion was correlated with mineralocorticoid metabolites excretion, except tetrahydroaldosterone, in both sexes (P < 0.01). There was an independent effect of Cd on sex hormone and corticosteroid synthesis and an interdependent effect on gluco- and mineralcorticoid production., Conclusion: Our findings provide evidence for a global stimulating effect on steroid synthesis already at low-dose Cd exposure. These findings might explain the association of Cd with diseases such as steroid-sensitive cancers or metabolic disorders., (Copyright © 2017 Endocrine Society)

Background: Genome-wide association studies have linked CYP17A1 coding for the steroid hormone synthesizing enzyme 17α-hydroxylase (CYP17A1) to blood pressure (BP). We hypothesized that the genetic signal may translate into a correlation of ambulatory BP (ABP) with apparent CYP17A1 activity in a family-based population study and estimated the heritability of CYP17A1 activity., Methods: In the Swiss Kidney Project on Genes in Hypertension, day and night urinary excretions of steroid hormone metabolites were measured in 518 participants (220 men, 298 women), randomly selected from the general population. CYP17A1 activity was assessed by 2 ratios of urinary steroid metabolites: one estimating the combined 17α-hydroxylase/17,20-lyase activity (ratio 1) and the other predominantly 17α-hydroxylase activity (ratio 2). A mixed linear model was used to investigate the association of ABP with log-transformed CYP17A1 activities exploring effect modification by urinary sodium excretion., Results: Daytime ABP was positively associated with ratio 1 under conditions of high, but not low urinary sodium excretion (P interaction <0.05). Ratio 2 was not associated with ABP. Heritability estimates (SE) for day and night CYP17A1 activities were 0.39 (0.10) and 0.40 (0.09) for ratio 1, and 0.71 (0.09) and 0.55 (0.09) for ratio 2 (P values <0.001). CYP17A1 activities, assessed with ratio 1, were lower in older participants., Conclusions: Low apparent CYP17A1 activity (assessed with ratio 1) is associated with elevated daytime ABP when salt intake is high. CYP17A1 activity is heritable and diminished in the elderly. These observations highlight the modifying effect of salt intake on the association of CYP17A1 with BP., (© American Journal of Hypertension, Ltd 2015. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: Blood pressure (BP) is known to aggregate in families. Yet, heritability estimates are population-specific and no Swiss data have been published so far. We estimated the heritability of ambulatory and office BP in a Swiss population-based sample., Methods: The Swiss Kidney Project on Genes in Hypertension is a population-based family study focusing on BP genetics. Office and ambulatory BP were measured in 1009 individuals from 271 nuclear families. Heritability was estimated for SBP, DBP, and pulse pressure using a maximum likelihood method implanted in the Statistical Analysis in Genetic Epidemiology software., Results: The 518 women and 491 men included in this analysis had a mean (±SD) age of 48.3 (±17.4) and 47.3 (±17.7) years, and a mean BMI of 23.8 (±4.2) and 25.9 (±4.1) kg/m, respectively. Narrow-sense heritability estimates (±standard error) for ambulatory SBP, DBP, and pulse pressure were 0.37 ± 0.07, 0.26 ± 0.07, and 0.29 ± 0.07 for 24-h BP; 0.39 ± 0.07, 0.28 ± 0.07, and 0.27 ± 0.07 for day BP; and 0.25 ± 0.07, 0.20 ± 0.07, and 0.30 ± 0.07 for night BP, respectively (all P < 0.001). Heritability estimates for office SBP, DBP, and pulse pressure were 0.21 ± 0.08, 0.25 ± 0.08, and 0.18 ± 0.07 (all P < 0.01)., Conclusions: We found significant heritability estimates for both ambulatory and office BP in this Swiss population-based study. Our findings justify the ongoing search for the genetic determinants of BP.

In patients with drug-resistant hypertension, chronic electric stimulation of the carotid baroreflex is an investigational therapy for blood pressure reduction. We hypothesized that changes in cardiac autonomic regulation can be demonstrated in response to chronic baroreceptor stimulation, and we analyzed the correlation with blood pressure changes. Twenty-one patients with drug-resistant hypertension were prospectively included in a substudy of the Device Based Therapy in Hypertension Trial. Heart rate variability and heart rate turbulence were analyzed using 24-hour ECG. Recordings were obtained 1 month after device implantation with the stimulator off and after 3 months of chronic electric stimulation (stimulator on). Chronic baroreceptor stimulation decreased office blood pressure from 185+/-31/109+/-24 mm Hg to 154+/-23/95+/-16 mm Hg (P<0.0001/P=0.002). Mean heart rate decreased from 81+/-11 to 76+/-10 beats per minute(-1) (P=0.001). Heart rate variability frequency-domain parameters assessed using fast Fourier transformation (FFT; ratio of low frequency:high frequency: 2.78 versus 2.24 for off versus on; P<0.001) were significantly changed during stimulation of the carotid baroreceptor, and heart rate turbulence onset was significantly decreased (turbulence onset: -0.002 versus -0.015 for off versus on; P=0.004). In conclusion, chronic baroreceptor stimulation causes sustained changes in heart rate variability and heart rate turbulence that are consistent with inhibition of sympathetic activity and increase of parasympathetic activity in patients with drug-resistant systemic hypertension; these changes correlate with blood pressure reduction. Whether the autonomic modulation has favorable cardiovascular effects beyond blood pressure control should be investigated in further studies.

The regulation of blood pressure is complex with several organs being involved. Intracellular calcium plays a crucial role in the regulation of cardiovascular functions: An increased influx of calcium into the vascular smooth muscle cells leads to an augmental muscular tone and therefore to an increased vascular resistance and rise in blood pressure. Parathormone plays a permissive role since it regulates the calcium-influx into the cells and thus increases the vasoconstrictive effect. There is a positive correlation between parathormone and blood pressure, present in primary as well as secondary hyperparathyroidism. Moreover, patients with essential hypertension have high parathormone levels already before hypertension is diagnosed. A calcium-rich diet (> 1000 mg calcium daily) slightly decreases blood pressure. This positive effect is due to parathormone suppression with a subsequently decreased calcium content in the vascular smooth muscle cells. A calcium-rich diet inhibits lipogenesis in the fat tissue; thus additionally improving the cardiovascular risk profile.