Response to morning surge, dipping, and sleep-time blood pressure as prognostic markers of cardiovascular risk

Renal tubular SGK1 is required to achieve blood pressure surge and circadian rhythm

Blood pressure (BP) follows a circadian pattern that rises during the active phase of the day (morning surge) and decreases during the inactive (night dipping) phase of the day. The morning surge coincides with increased circulating glucocorticoids and aldosterone, ligands for glucocorticoid receptors and mineralocorticoid receptors, respectively. Serum- and glucocorticoid-induced kinase 1 (SGK1), a clock-controlled and glucocorticoid receptor- and mineralocorticoid receptor-induced gene, plays a role in BP regulation in human and animal models. However, the role of SGK1 in BP circadian regulation has not yet been demonstrated. Using telemetry, we analyzed BP in the inducible renal tubule-specific Sgk1Pax8/LC1 model under basal K+ diet (1% K+) and high-K+ diet (HKD; 5% K+). Our data revealed that, under basal conditions, renal SGK1 plays a minor role in BP regulation; however, after 1 wk of HKD, Sgk1Pax8/LC1 mice exhibited significant defects in diastolic BP (DBP), including a blunted surge, a decreased amplitude, and reduced day/night differences. After prolonged HKD (7 wk), Sgk1Pax8/LC1 mice had lower BP than control mice and exhibited reduced DBP amplitude, together with decreased DBP day/night differences and midline estimating statistic of rhythm (MESOR). Interestingly, renal SGK1 deletion increased pulse pressure, likely secondary to an increase in circulating aldosterone. Taken together, our data suggest that 1) the kidney plays a significant role in setting the BP circadian rhythm; 2) renal tubule SGK1 mediates the BP surge and, thus, the day/night BP difference; 3) long-term renal SGK1 deletion results in lower BP in mutant compared with control mice; and 4) renal SGK1 indirectly regulates pulse pressure due to compensatory alterations in aldosterone levels.NEW & NOTEWORTHY Dysregulation of blood pressure (BP) circadian rhythm is associated with metabolic, cardiovascular, and kidney diseases. Our study provides experimental evidence demonstrating, for the first time, that renal tubule serum- and glucocorticoid-induced kinase 1 (SGK1) plays an essential role in inducing the BP surge. Inhibitors and activators of SGK1 signaling are parts of several therapeutic strategies. Our findings highlight the importance of the drug intake timing to be in phase with SGK1 function to avoid dysregulation of BP circadian rhythm.

The impact of acetylsalicylic acid dosed at bedtime on circadian rhythms of blood pressure in the high-risk group of cardiovascular patients-a randomized, controlled trial

Purpose

Time of drug administration may significantly influence its effect. The aim of the present study was to investigate the effect of ASA (administrated in the morning or in the evening) on the anti-hypertensive effect and diurnal blood pressure profile in the high-risk group of cardiovascular patients.

Methods

All patients (n = 114) had been diagnosed with coronary heart disease and arterial hypertension prior to the enrolment and had been treated with 75 mg per day of ASA in the morning. The patients were randomly assigned to one of the two study groups receiving 75 mg of ASA per day in a single antiplatelet therapy for 3 months in the morning (n = 58) or in the evening (n = 56). The control group (n = 61) consisted of patients with arterial hypertension but without coronary heart disease, not receiving ASA. In all the patients, during each visit, clinical blood pressure (BP) and ambulatory blood pressure measurements (ABPM) were performed.

Results

There was a significant reduction in 24-h BP and blood pressure at night in the ASA group evening group compared with the ASA morning group and the control group.

Conclusions

The present study demonstrated that compared with the use of ASA in the morning, its administration in the evening may lead to favourable drop in the ABPM and an improvement of the diurnal profile in the high-risk group of cardiovascular patients who are not naïve to ASA.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02997-8) contains supplementary material, which is available to authorized users.

The Effects of Eplerenone on the Circadian Blood Pressure Pattern and Left Ventricular Hypertrophy in Patients with Obstructive Sleep Apnea and Resistant Hypertension-A Randomized, Controlled Trial

The obstructive sleep apnea (OSA) is highly associated with various significant cardiovascular outcomes such as resistant hypertension (RAH). Despite this, as of now the relationship between high night-time blood pressure (BP) and left ventricular hypertrophy (LVH) in patients with OSA and RAH is not fully understood. The aim of this study was to assess the influence of the addition of eplerenone to a standard antihypertensive therapy on parameters of 24-h ambulatory blood pressure measurement (ABPM) as well as on the results of echocardiography and polysomnography in patients with OSA and RAH. The patients were randomly assigned to one of the two study groups: the treatment group, receiving 50 mg/d eplerenone orally for 6 months (n = 51) and the control group, remaining on their standard antihypertensive therapy (n = 51). After that period, a significant reduction in the night-time BP parameters in the treatment group including an increased night blood pressure fall from 4.6 to 8.9% was noted. Additionally, the number of non-dipper patients was reduced by 45.1%. The treatment group also revealed a decrease in left ventricular hypertrophy and in the apnea-hypopnea index (AHI) with a positive correlation being observed between these two parameters. This study is the first to report the improvement of the circadian BP profile and the improvement of the left ventricle geometry in patients with OSA and RAH following the addition of selective mineralocorticoid receptor antagonists to antihypertensive therapy.