Aldosterone hyperreactivity to acute psychosocial stress induction in men with essential hypertension

Increased daytime and awakening salivary free aldosterone in essential hypertensive men

Background

While aldosterone plays an important role in blood pressure regulation, its role in essential hypertension (EHT) remains unclear. Here, we systematically investigated the secretion of biologically-active free aldosterone in saliva in response to awakening (AldAR) and during the day (AldDay) in EHT compared to normotensive controls (NT).

Methods

In 30 men with EHT and 30 age-matched NT, AldAR saliva samples were collected immediately after awakening and 15, 30, 45, and 60 min thereafter and AldDay samples were collected from 08:30-22:00 h on two consecutive days.

Results

Over the course of the day, men with EHT had higher repeated AldDay levels compared to NT (p = .002) with higher concentrations in the morning hours (p's ≤ .047), a steeper decline over the course of the day (p's ≤ .018), and similar concentrations in the evening (p's ≥ .21). Regarding AldAR, we observed higher concentrations in EHT at awakening (p = .017) and borderline higher concentrations at 15 min (p = .086). No differences were found 30-60 min after awakening (p's ≥ .34). Analyses with repeated and aggregated AldAR levels resulted in borderline significantly higher free aldosterone in EHT (p's ≤ .077). Complementary analyses confirmed linear associations between higher blood pressure and higher AldAR and AldDay levels.

Conclusions

Our data point to elevated salivary free aldosterone secretion in EHT over the course of the day, particularly in the morning hours. As the free aldosterone fraction is considered biologically active, our data may point to a biological mechanism underlying EHT.

A randomized vagus nerve stimulation study demonstrates that serum aldosterone levels decrease with age in women, but not in men

In this randomized, sham-controlled study, we explored the effects of acute transcutaneous vagus nerve stimulation (tVNS) on serum aldosterone in 20 younger (21-26 years) and 19 older (40-70 years) healthy participants. Blood samples were collected on two different days before and after a 20-min application of active tVNS at the inner tragus or sham stimulation of the earlobe. Irrespective of the stimulation mode, aldosterone levels decreased from pre- to post-stimulation in both the young (active: β = - 1.610 (- 2.855, - 0.365), p = 0.022; sham: β = - 0.857 (- 2.102, 0.388), p = 0.257) and the old cohort (active: β = - 1.969 (- 3.234, - 0.703), p = 0.005; sham: β = - 1.334 (- 2.600, - 0.069), p = 0.063). Although this decline was significant during active tVNS, the difference in estimated β-coefficients between active and sham stimulation was not statistically significant in either cohort. Nevertheless, aldosterone concentrations showed a significant interaction effect between sex and age (p = 0.001). Among all study participants, younger women (23.3 ± 1.6 years) had the highest mineralocorticoid levels (pre active: 172.1 ± 102.0 pg/ml, pre sham: 214.3 ± 82.3 pg/ml), whereas the lowest were observed in older females (59.4 ± 9.4 years) (pre active: 104.9 ± 85.8 pg/ml, pre sham: 81.1 ± 53.8 pg/ml). This post hoc analysis did not suggest that active auricular tVNS reduces serum aldosterone levels compared to sham stimulation in healthy subjects. However, serum aldosterone levels differed among subjects depending on their age and sex, irrespective of tVNS.

Physiological reactivity to acute mental stress in essential hypertension-a systematic review

Objective

Exaggerated physiological reactions to acute mental stress (AMS) are associated with hypertension (development) and have been proposed to play an important role in mediating the cardiovascular disease risk with hypertension. A variety of studies compared physiological reactivity to AMS between essential hypertensive (HT) and normotensive (NT) individuals. However, a systematic review of studies across stress-reactive physiological systems including intermediate biological risk factors for cardiovascular diseases is lacking.

Methods

We conducted a systematic literature search (PubMed) for original articles and short reports, published in English language in peer-reviewed journals in November and December 2022. We targeted studies comparing the reactivity between essential HT and NT to AMS in terms of cognitive tasks, public speaking tasks, or the combination of both, in at least one of the predefined stress-reactive physiological systems.

Results

We included a total of 58 publications. The majority of studies investigated physiological reactivity to mental stressors of mild or moderate intensity. Whereas HT seem to exhibit increased reactivity in response to mild or moderate AMS only under certain conditions (i.e., in response to mild mental stressors with specific characteristics, in an early hyperkinetic stage of HT, or with respect to certain stress systems), increased physiological reactivity in HT as compared to NT to AMS of strong intensity was observed across all investigated stress-reactive physiological systems.

Conclusion

Overall, this systematic review supports the proposed and expected generalized physiological hyperreactivity to AMS with essential hypertension, in particular to strong mental stress. Moreover, we discuss potential underlying mechanisms and highlight open questions for future research of importance for the comprehensive understanding of the observed hyperreactivity to AMS in essential hypertension.

Hyperreactivity of Salivary Alpha-Amylase to Acute Psychosocial Stress and Norepinephrine Infusion in Essential Hypertension

It is unknown whether the observed general physiological hyperreactivity to acute psychosocial stress in essential hypertension also extends to salivary alpha-amylase (sAA), a surrogate sympathetic nervous system marker. Here, we investigated sAA reactivity to acute psychosocial stress in essential hypertensive males (HT) as compared to normotensive controls (NT). To shed light on underlying mechanisms, we moreover tested for sAA reactivity following a standardized norepinephrine (NE) infusion. We hypothesized that both acute psychosocial stress and an NE infusion of similar duration would lead to greater sAA reactivity in HT than in NT. In the stress study, we examined sAA reactivity to 15 min of acute psychosocial stress induced by the Trier Social Stress Test (TSST) in 19 HT and 23 NT up to 40 min after stress. In the infusion study, 20 HT and 22 NT received a standardized NE infusion (5 μg/mL/min) over 15 min mimicking NE release in reaction to acute psychosocial stress. HT exhibited greater sAA reactivity to the TSST as compared to NT (p = 0.049, η_p² = 0.08, f = 0.29). In reaction to the standardized NE infusion, HT showed higher sAA reactivity as compared to NT (p = 0.033, η_p² = 1.00, f = 0.33). Our findings suggest stress-induced sAA hyperreactivity in essential hypertension that seems to be at least in part mediated by a higher reactivity to a standardized amount of NE in HT. With respect to clinical implications, sAA stress reactivity may serve as a noninvasive marker indicative of early cardiovascular risk.

Aldosterone secretion during the day: Salivary aldosterone awakening response and daytime levels

BACKGROUND

The mineralocorticoid hormone aldosterone is a key regulator of the sodium-potassium balance and blood pressure. In excess, aldosterone relates to hypertension and cardiovascular disease (CVD). Here, we systematically investigated aldosterone secretion during the day in terms of salivary aldosterone awakening response (AldAR) and salivary aldosterone daytime levels (AldDay) under controlled conditions in participants' natural environment including assessment of potential confounding variables.

METHODS

In 40 healthy young men, saliva samples for AldAR were collected immediately after awakening and 15, 30, 45, and 60 min thereafter. AldDay levels were measured in 1 h intervals from 9:00-22:00 h. Analyses were complemented by salivary cortisol assessment. Fluid and food intake was standardized and as potential confounders, we assessed awakening time and sleep duration, age, BMI and MAP, as well as chronic stress.

RESULTS

Awakening was followed by significant increases in salivary aldosterone (p = .004, f= 0.31), returning to baseline levels > 60 min later. Longer sleep duration was associated with lower AldAR (p < .001, f= 0.36). Over the course of the day we observed a continuous decrease of AldDay (p < .001, f= 0.45). Longer sleep duration (p = .097, f= .21), later time of awakening (p < .001, f= .29), and higher chronic stress (p = .041, f= .23) were associated with AldDay characteristics. Circadian aldosterone secretion was positively associated with most cortisol measures.

CONCLUSIONS

We observed an awakening response in salivary aldosterone and could confirm a decrease in aldosterone levels during the day, comparable to cortisol. Significant confounders were sleep-related variables and chronic stress. Clinical implications of circadian aldosterone secretion with respect to CVD risk remain to be elucidated.