Update in Hypertension Therapy

Optimal cutoff of the abdominal skinfold thickness (AST) to predict hypertension among Chinese children and adolescents

Previous studies have shown that the correlation between the abdominal skinfold thickness (AST) and hypertension is better than that observed using the body mass index (BMI) or waist-to-height ratio (WHtR). We aimed to explore the optimal cutoff of the AST to predict childhood hypertension. The AST percentiles were calculated based on 215,223 students from the Chinese National Survey on Students' Constitution and Health (CNSSCH) in 2010 using the LMS method. Logistic regression model and Receiver operating characteristic (ROC) curves were used to evaluate the optimal cutoff of the AST to predict hypertension based on a sample of 683 children aged 8-15 years. The prevalence of hypertension was 5.71% (5.45% in boys and 6.01% in girls). The area under the ROC curve [AUC (95% CI)] values of the BMI, WHtR and AST to predict hypertension were 0.62 (0.47-0.77), 0.61 (0.45-0.76), and 0.67 (0.54-0.80) in boys and 0.59 (0.46-0.71), 0.65 (0.50-0.80), and 0.70 (0.57-0.83) in girls, respectively. The AUC value at P₈₅ of AST in boys and that at P₉₀ of AST in girls to predict hypertension were higher than other percentile values of AST. The OR (95% CI) values of the optimal cutoff of the AST associated with hypertension were 2.90 (1.17-7.20) and 4.91 (1.81-13.31) in boys and girls, respectively, and were higher than those associated with overweight/obesity (based on BMI) and abdominal obesity (based on WHtR).The AST was more effectively associated with hypertension than the BMI and WHtR, and the optimal cutoff to predict hypertension was at P₈₅ for boys and P₉₀ for girls.

A review of clinically significant drug-drug interactions involving angiotensin II receptor antagonists and antiepileptic drugs

INTRODUCTION

Angiotensin II receptor blockers are widely used for the treatment of arterial hypertension and heart failure. However, recent studies on animal models of seizures showed that in the brain, the renin-angiotensin-aldosterone system might be involved in neuroinflammation; therefore, the administration of angiotensin II receptor blockers that cross the blood/brain barrier, reduces not only blood pressure but reduces neuroinflammation-induced neuronal injury. Apart from this neuroprotective effect, these drugs exhibit anticonvulsant activity in animal models of seizures, and losartan is associated with a probable anti-epileptogenic activity.

AREAS COVERED

In this review, we intended to highlight the role of drug-drug interactions involving angiotensin II receptor antagonists with antiepileptic drugs accompanied by a brief characteristic of the role of RAS in neuroinflammation.

EXPERT OPINION

Some combinations of antiepileptic drugs (lamotrigine or valproate) with sartans are particularly effective in terms of enhanced seizure control. Considering a possible anti-epileptogenic activity of losartan, its combinations with antiepileptic drugs may prove especially beneficial in epileptogenesis inhibition.

Contribution of Baroreflex Afferent Pathway to NPY-Mediated Regulation of Blood Pressure in Rats

Neuropeptide Y (NPY), a metabolism-related cardiovascular factor, plays a crucial role in blood pressure (BP) regulation via peripheral and central pathways. The expression of NPY receptors (Y₁R/Y₂R) specific to baroreflex afferents impacts on the sexually dimorphic neural control of circulation. This study was designed to investigate the expression profiles of NPY receptors in the nodose ganglion (NG) and nucleus tractus solitary (NTS) under hypertensive conditions. To this end, rats with hypertension induced by N^G-nitro-L-arginine methylester (L-NAME) or high fructose drinking (HFD), and spontaneously hypertensive rats (SHRs) were used to explore the effects/mechanisms of NPY on BP using functional, molecular, and electrophysiological approaches. The data showed that BP was elevated along with baroreceptor sensitivity dysfunction in model rats; Y₁R was up- or down-regulated in the NG or NTS of male and female HFD/L-NAME groups, while Y₂R was only down-regulated in the HFD groups as well as in the NG of the male L-NAME group. In SHRs, Y₁R and Y₂R were both down-regulated in the NTS, and not in the NG. In addition to NPY-mediated energy homeostasis, leptin-melanocortin activation may be essential for metabolic disturbance-related hypertension. We found that leptin and α-melanocyte stimulating hormone (α-MSH) receptors were aberrantly down-regulated in HFD rats. In addition, α-MSH concentrations were reduced and NPY concentrations were elevated in the serum and NTS at 60 and 90 min after acute leptin infusion. Electrophysiological recordings showed that the decay time-constant and area under the curve of excitatory post-synaptic currents were decreased by Y₁R activation in A-types, whereas, both were increased by Y₂R activation in Ah- or C-types. These results demonstrate that sex- and afferent-specific NPY receptor expression in the baroreflex afferent pathway is likely to be a novel target for the clinical management of metabolism-related and essential hypertension.

Angiotensin-Converting Enzyme 2 in the Rostral Ventrolateral Medulla Regulates Cholinergic Signaling and Cardiovascular and Sympathetic Responses in Hypertensive Rats

The rostral ventrolateral medulla (RVLM) is a key region in cardiovascular regulation. It has been demonstrated that cholinergic synaptic transmission in the RVLM is enhanced in hypertensive rats. Angiotensin-converting enzyme 2 (ACE2) in the brain plays beneficial roles in cardiovascular function in hypertension. The purpose of this study was to determine the effect of ACE2 overexpression in the RVLM on cholinergic synaptic transmission in spontaneously hypertensive rats (SHRs). Four weeks after injecting lentiviral particles containing enhanced green fluorescent protein and ACE2 bilaterally into the RVLM, the blood pressure and heart rate were notably decreased. ACE2 overexpression significantly reduced the concentration of acetylcholine in microdialysis fluid from the RVLM and blunted the decrease in blood pressure evoked by bilateral injection of atropine into the RVLM in SHRs. In conclusion, we suggest that ACE2 overexpression in the RVLM attenuates the enhanced cholinergic synaptic transmission in SHRs.

Management of Small Incidental Intracranial Aneurysms

Advances in neuroimaging and its widespread use for screening have increased the diagnosis of unruptured intracranial aneurysms (UIAs), including small-sized UIAs. The clinical management of these small-sized UIAs requires a patient-specific judgment of the risk of aneurysm rupture, if not treated, versus the risk of complications from surgical or endovascular treatment. Experienced cerebrovascular teams recommend treating small UIAs in young patients or in patients with more than one aneurysm rupture risk factor who also have a reasonable life expectancy. However, individual overall assessment of risk is critical for patients with UIAs to decide the next steps of care.

Angiotensin II Type 1 Receptor Blockers Inhibit KAT II Activity in the Brain-Its Possible Clinical Applications

Angiotensin II receptor blockers (ARBs) are one of the most frequently recommended antihypertensive drugs. Apart from their activity towards the circulatory system, ARBs also penetrate the blood-brain barrier and display neuroprotective effects. Kynurenic acid (KYNA) is an endogenous metabolite of tryptophan produced by kynurenine aminotransferase II (KAT II) in the brain. Antagonism towards all ionotropic glutamate (GLU) receptors is the main mechanism of KYNA action. An elevated brain level of KYNA is linked with memory impairment and psychotic symptoms. The aim of this study was to examine the influence of three ARBs: irbesartan, losartan, and telmisartan on KYNA production and KAT II activity in rat brain. The effect of ARBs on KYNA production was analyzed in rat brain cortical slices and on isolated KAT II enzyme. Irbesartan, losartan, and telmisartan decreased KYNA production and KAT II activity in a dose-dependent manner in rat brain cortex in vitro. Molecular docking suggested that the examined ARBs could bind to an active site of KAT II. In conclusion, ARBs decrease KYNA production in rat brain by direct inhibition of KAT II enzymatic activity. This novel mechanism of ARBs action may be advantageous in the treatment of cognitive impairment or the management of schizophrenia.