Renoprotection, renin inhibition, and blood pressure control: the impact of aliskiren on integrated blood pressure control

Successful treatment of severe renal failure caused by malignant hypertension using a combination of renin-angiotensin-aldosterone system inhibitors: a case report

Marked activation of the renin-angiotensin-aldosterone system (RAAS) plays an important role in malignant hypertension (MHT) by worsening hypertension and renal function. The rates of readmission for severe hypertension and cardiovascular disease in such emergencies are high, suggesting that suppression of the RAAS may be inadequate during the acute phase in some cases. This report presents a case of MHT complicated with renal insufficiency (creatinine 3.93 mg/dL) and massive proteinuria, in which antihypertensive therapy, including an angiotensin receptor blocker, aliskiren, and spironolactone, normalized blood pressure (BP) and preserved renal function. Plasma renin activity was extremely high (131.9 ng/mL/h) on admission but normalized within almost 2 weeks. Although aliskiren and spironolactone were discontinued before discharge, BP was well controlled and renal function was further improved (creatinine 1.14 mg/dL) at follow-up 24 months later. This case of renal failure induced by MHT was successfully treated with a combination of RAAS inhibitors during the acute phase. The controlled BP and improved renal function in this patient suggest that adequate suppression of the RAAS cascade during the acute phase is potentially effective in terms of breaking the vicious cycle of MHT with hyperreninemia.

Formaldehyde causes an increase in blood pressure by activating ACE/AT1R axis

Previous studies suggest some link between formaldehyde exposure and harmful cardiovascular effects. But whether exposure to formaldehyde can cause blood pressure to rise, and if so, what the underlying mechanism is, remains unclear. In this study, C57BL/6 male mice were exposed to 0.1, 0.5, 2.5 mg/m³ of gaseous formaldehyde for 4 h daily over a three-week period. The systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP) and heart rate (HR) of the mice were measured by tail-cuff plethysmography, and any histopathological changes in the target organs of hypertension were investigated. The results showed that exposure to formaldehyde did cause a significant increase in blood pressure and heart rate, and resulted in varying degrees of damage to the heart, aortic vessels and kidneys. To explore the underlying mechanism, a specific inhibitor of angiotensin converting enzyme (ACE) was used to block the ACE/AT1R axis. We observed the levels of ACE and angiotensin II type 1 receptor (AT1R), as well as the bradykinin (BK) in cardiac cytoplasm. The data suggest that exposure to formaldehyde induced an increase in the expression of ACE and AT1R, and decreased the levels of BK. Strikingly, treatment with 5 mg/kg/d ACE inhibitor can attenuate the increase in blood pressure and the pathological changes caused by formaldehyde exposure. This result has improved our understanding of whether, and how, formaldehyde exposure affects the development of hypertension.

Clinical efficacy, safety and tolerability of Aliskiren Monotherapy (AM): an umbrella review of systematic reviews

BACKGROUND

Aliskiren is a newly developed drug. Its role in lowering BP has been recognized. However, the role of aliskiren in treating heart and renal diseases are still controversial.

OBJECTIVE

To evaluate the existing evidence about clinical efficacy, safety and tolerability of aliskiren monotherapy (AM).

METHODS

An umbrella review of systematic reviews of interventional studies. We searched Pubmed, Embase and Cochrane Library up to June 2019. Two reviewers applied inclusion criteria to the select potential articles independently. The extract and analyze of accessible data were did by two reviewers independently too. Discrepancies were resolved with discussion or the arbitration of the third author.

RESULTS

Eventually, our review identified 14 eligible studies. Results showed that for essential hypertension patients, aliskiren showed a great superiority over placebo in BP reduction, BP response rate and BP control rate. Aliskiren and placebo, ARBs or ACEIs showed no difference in the number or extent of adverse events. For heart failure patients, AM did not reduce BNP levels (SMD -0.08, - 0.31 to 0.15) or mortality rate (RR 0.76, 0.32 to 1.80), but it decreased NT-proBNP (SMD -0.12, - 0.21 to - 0.03) and PRA levels (SMD 0.52, 0.30 to 0.75), increased PRC levels (SMD -0.66, - 0.8 to - 0.44). For patients who are suffered from hypertension and diabetes and/or nephropathy or albuminuria at the same time, aliskiren produced no significant effects (RR 0.97, 0.81 to 1.16).

CONCLUSION

We found solid evidence to support the benefits of aliskiren in the treatment of essential hypertension, aliskiren can produce significant effects in lowering BP and reliable safety. However, the effects of aliskiren in cardiovascular and renal outcomes were insignificant.

TRIAL REGISTRATION

Study has been registered in PROSPERO (CRD42019142141).

Direct renin inhibition improves parasympathetic function in diabetes

AIM

The renin-angiotensin-aldosterone system (RAAS) and autonomic nervous system regulate the cardiovascular system. Blockade of the RAAS may slow the progression of end-organ damage. Direct renin inhibition offers a means for blocking the RAAS. The objective of this study was to examine the effect of direct renin inhibition on cardiovascular autonomic function.

METHODS

In this double-blind, placebo-controlled trial, 60 individuals with diabetes were randomly assigned to 300 mg of aliskiren or placebo once daily for 6 weeks. The primary end point was a change in tests of cardiovascular autonomic function. Autonomic function was assessed by power spectral analysis and RR-variation during deep breathing [i.e. mean circular resultant (MCR), expiration/inspiration (E/I) ratio]. The MCR and E/I ratio assess parasympathetic function. Secondary measures included change in biochemical parameters [e.g. plasma renin activity, leptin and interleukin-6]. Change in cardiovascular autonomic function and blood analytes were analysed by a mixed effects model for repeated measures.

RESULTS

Baseline characteristics were similar between treatment groups. In response to aliskiren compared with placebo, blood pressure was reduced as well as plasma renin activity [from 2.4 ± 3.8 (mean ± standard deviation) to 0.5 ± 0.4 µg/l/h, p < 0.001]. There was a significant interaction (aliskiren × visit) for MCR (p = 0.003) and E/I ratio (p = 0.003) indicating improvement in MCR and E/I ratio for those on aliskiren. MCR means, baseline vs. follow-up, were 41.8 ± 19.7 vs. 50.8 ± 26.1 (aliskiren) and 38.2 ± 23.6 vs. 37.5 ± 24.1 (placebo).

CONCLUSIONS

Parasympathetic function (i.e. MCR and E/I ratio) was enhanced by downregulation of the RAAS.