Pleiotropic effects of angiotensin receptor blockers: addressing comorbidities by optimizing hypertension therapy

Long-term mortality and cardiovascular events of seven angiotensin receptor blockers in hypertensive patients: Analysis of a national real-world database: A retrospective cohort study

Background and Aims

Although many angiotensin receptor blockers (ARBs) are widely used, comparative data regarding their impact on clinical outcomes are limited. We aimed to compare the clinical effectiveness of seven ARBs on long-term cardiovascular outcomes in Korean patients with hypertension.

Methods

Using the Korean National Health Insurance Service database, the data of 780,785 patients with hypertension without cardiovascular disease (CVD) who initiated ARB treatment (candesartan, fimasartan, irbesartan, losartan, olmesartan, telmisartan, or valsartan) in 2014 and underwent this treatment for more than 6 months, were analyzed. Cox-regression analysis was performed using Losartan as a comparator, as it was the most widely used drug, by adjusting age, sex, diabetes, dyslipidemia, smoking, alcohol drinking, exercise, body mass index, systolic blood pressure, albuminuria, estimated glomerular filtration rate, and concomitant medications. The occurrence of mortality and the rate of major adverse cardiovascular events (MACEs) of the six ARBs was compared with that of losartan.

Results

The median follow-up duration was 5.94 (interquartile range, 5.87-5.97) years. In the crude analysis of all-cause mortality and MACEs, fimasartan exhibited the lowest event rates. In the Cox-regression analysis with adjustment, there was no significant difference in all-cause mortality among ARBs. The risk of MACEs with ARBs was similar to that with losartan, although the risks with irbesartan (hazard ratio [HR], 1.079; 95% confidence interval [CI], 1.033-1.127; p = 0.007) and candesartan (HR: 1.066; 95% CI, 1.028-1.106; p = 0.015) were slightly higher.

Conclusion

In a Korean population of patients with hypertension without CVD, six different ARBs showed similar efficacy to losartan in terms of long-term mortality and MACEs. Further well-designed prospective studies are required to confirm our findings.

Renin-angiotensin-aldosterone system inhibition decreased contrast-associated acute kidney injury in chronic kidney disease patients

BACKGROUND/PURPOSE

Chronic kidney disease (CKD) is a risk factor for contrast associated acute kidney injury (CA-AKI). The risk of renin-angiotensin-aldosterone system inhibitor (RASi) use in patients with CKD before the administration of contrast is not clear.

METHODS

In this nested case-control study, 8668 patients received contrast computed tomography (CT) from 2013 to 2018 during index administration in a multicenter hospital cohort. The identification of AKI is based on the Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria within 48 h after contrast medium used.

RESULTS

Finally, 986 patients (age, 63.36 ± 12.22; men, 72.92%) with CKD (estimated glomerular filtration rate (eGFR) = 35.0 ± 19.8 mL/min/1.73 m²) were eligible for analysis. After the index date, RASi users (n = 315) were less likely to develop CA-AKI (13.65% vs 30.4%, p < 0.001), and had a lower hospital mortality (8.25% vs 19.23%, p < 0.001) compared with non-users. The pre-contrast use of RASi decrease the risk of AKI (OR, 0.342, p < 0.001) and hospital mortality (OR, 0.602, p = 0.045). Even a few defined daily doses (DDDs) of RASi treatment, more than 0.02 prior to contrast CT could attenuate CA-AKI. The hospital mortality was higher in RASi non-users if their eGFR value was more than 17.9 mL/min/1.73 m².

CONCLUSION

RASi use in patients with CKD prior to contrast CT has the potential to mitigate the incidence of AKI and hospital mortality. Even a low dose of RASi will noticeably decrease the risk of AKI and will not increase the risk of hyperkalemia.

Losartan improves visceral sensation and gut barrier in a rat model of irritable bowel syndrome

BACKGROUND

Lipopolysaccharide (LPS) or repeated water avoidance stress (WAS) induces visceral allodynia and colonic hyperpermeability via corticotropin-releasing factor (CRF) and proinflammatory cytokines, which is considered to be a rat irritable bowel syndrome (IBS) model. As losartan is known to inhibit proinflammatory cytokine release, we hypothesized that it improves these visceral changes.

METHODS

The threshold of visceromotor response (VMR), that is, abdominal muscle contractions induced by colonic balloon distention was electrophysiologically measured in rats. Colonic permeability was determined in vivo by quantifying the absorbed Evans blue in colonic tissue for 15 minutes spectrophotometrically.

KEY RESULTS

Lipopolysaccharide (1 mg kg^-1 ) subcutaneously (s.c.) reduced the threshold of VMR and increased colonic permeability. Losartan (5-25 mg kg^-1  s.c.) for 3 days inhibited these changes in a dose-dependent manner. Moreover, repeated WAS (1 hour daily for 3 days) or intraperitoneal injection of CRF (50 µg kg^-1 ) induced the similar visceral changes as LPS, which were also eliminated by losartan. These effects by losartan in LPS model were reversed by GW9662 (a peroxisome proliferator-activated receptor-γ [PPAR-γ] antagonist), N^G -nitro-L-arginine methyl ester (a nitric oxide [NO] synthesis inhibitor), or naloxone (an opioid receptor antagonist). Moreover, it also inhibited by sulpiride (a dopamine D₂ receptor antagonist) or domperidone (a peripheral dopamine D₂ antagonist).

CONCLUSION & INFERENCES

Losartan prevented visceral allodynia and colonic hyperpermeability in rat IBS models. These actions may be PPAR-γ-dependent and also mediated by the NO, opioid, and dopamine D₂ pathways. Losartan may be useful for IBS treatment.

Roles of Nitric Oxide and Prostaglandins in the Sustained Antihypertensive Effects of Acanthospermum hispidum DC. on Ovariectomized Rats with Renovascular Hypertension

Although Acanthospermum hispidum is used in Brazilian folk medicine as an antihypertensive, no study evaluated its effects on a renovascular hypertension and ovariectomy model. So, this study investigated the mechanisms involved in the antihypertensive effects of an ethanol-soluble fraction obtained from A. hispidum (ESAH) using two-kidney-one-clip hypertension in ovariectomized rats (2K1C plus OVT). ESAH was orally administered at doses of 30, 100, and 300 mg/kg, daily, for 28 days, after 5 weeks of surgery. Enalapril (15 mg/kg) and hydrochlorothiazide (25 mg/kg) were used as standard drugs. Diuretic activity was evaluated on days 1, 7, 14, 21, and 28. Systolic, diastolic, and mean blood pressure and heart rate were recorded. Serum creatinine, urea, thiobarbituric acid reactive substances, nitrosamine, nitrite, aldosterone, vasopressin levels, and ACE activity were measured. The vascular reactivity and the role of nitric oxide (NO) and prostaglandins (PG) in the vasodilator response of ESAH on the mesenteric vascular bed (MVB) were also investigated. ESAH treatment induced an important saluretic and antihypertensive response, therefore recovering vascular reactivity in 2K1C plus OVT-rats. This effect was associated with a reduction of oxidative and nitrosative stress with a possible increase in the NO bioavailability. Additionally, a NO and PG-dependent vasodilator effect was observed on the MEV.

Renal sympathetic denervation in resistant hypertension

Resistant hypertension remains a major clinical problem despite the available multidrug therapy. Over the next decades, its incidence will likely increase given that it is strongly associated with older age and obesity. Resistant hypertension patients have an increased cardiovascular risk, thus effective antihypertensive treatment will provide substantial health benefits. The crosstalk between sympathetic nervous system and kidneys plays a crucial role in hypertension. It influences several pathophysiological mechanisms such as the central sympathetic tone, the sodium balance and the systemic neurohumoral activation. In fact, studies using several animal models demonstrated that the renal denervation prevented and attenuated hypertension in multiple species. Large reductions in blood pressure were also observed in malignant hypertension patients submitted to sympathectomy surgeries. However, these approaches had an unacceptably high rates of periprocedural complications and disabling adverse events. Recently, an innovative non-pharmacological therapy that modulates sympathetic activation has been successfully developed. Renal sympathetic percutaneous denervation is an endovascular procedure that uses radiofrequency energy to destroy the autonomic renal nerves running inside the adventitia of renal arteries. This method represents a promising new approach to the strategy of inhibiting the sympathetic nervous system. The aim of this review is to examine the background knowledge that resulted in the development of this hypertension treatment and to critically appraise the available clinical evidence.