Potential mechanisms of stroke benefit favoring losartan in the Losartan Intervention For Endpoint reduction in hypertension (LIFE) study

Comparison between invasive and non-invasive assessment of blood pressure in hypertensive disorders of pregnancy

BACKGROUND

The management of hypertensive disorders of pregnancy (HDP) during hospitalization requires an accurate blood pressure (BP) measurement, mainly by invasive intra-arterial reading. Nevertheless, little is known about the precision of non-invasive (NI) central BP measurements in HDP. We aimed to assess the accuracy of NI central BP assessment in comparison to invasive BP measurement in HDP. This cross-sectional study included all patients with HDP that were admitted to university hospitals for high BP control, from December 2018 till December 2019, and 10 healthy matched non-hypertensive controls. Patients were compared for demographic, anthropometric, and echocardiographic data. In all subjects, invasive BP assessment was done by radial arterial cannulation and NI assessment of BP was performed by an oscillometric automated device (Mobil-O-Graph); the comparison was done after initial control of BP.

RESULTS

One hundred patients were included and divided into 3 groups (pre-existing hypertension (HTN), gestational HTN, and pre-eclampsia). There was no statistically significant difference between NI central and invasive methods in measuring both systolic BP (SBP) (126.39 ± 14.5 vs 127.43 ± 15.3, p = 0.5) and diastolic BP (82.41 ± 9.0 vs 83.78 ± 8.9, p = 0.14) among the total studied population. A strong positive correlation was found between NI central and invasive SBP (r = 0.96, p < 0.001). HDP was associated with an increase in arterial stiffness, left ventricular diastolic dysfunction, and complications.

CONCLUSION

Non-invasive measurement of BP using oscillometric automated devices is as accurate as the invasive method, and it is a practical safe method in pregnant women with hypertensive disorders (CTR no. = NCT04303871).

Angiotensin Receptor Blockers Are Not Just for Hypertension Anymore

Beyond blood pressure control, angiotensin receptor blockers reduce common injury mechanisms, decreasing excessive inflammation and protecting endothelial and mitochondrial function, insulin sensitivity, the coagulation cascade, immune responses, cerebrovascular flow, and cognition, properties useful to treat inflammatory, age-related, neurodegenerative, and metabolic disorders of many organs including brain and lung.

Fifteen years of LIFE (Losartan Intervention for Endpoint Reduction in Hypertension)-Lessons learned for losartan: An "old dog playing good tricks"

There is an unmet need to prevent cardiovascular disease and chronic kidney disease development and progression worldwide. Losartan, the first angiotensin receptor blocker, was shown to exert significant cardioprotective and renoprotective effects in the LIFE (Losartan Intervention for Endpoint Reduction in Hypertension) and RENAAL (Reduction of Endpoints in NIDDM With the Angiotensin II Antagonist Losartan) trials. Losartan significantly prevented stroke and decreased serum uric acid levels and the rates of new-onset diabetes mellitus and atrial fibrillation. The present review discusses the LIFE (and its subanalyses) and RENAAL trials and the translation of their results to clinical practice. The place of losartan in the current guidelines for hypertension management is also discussed. Losartan still represents an efficacious, safe, and cost-effective therapeutic option in patients with hypertension who have left ventricular hypertrophy. Losartan is a useful antihypertensive agent for stroke prevention and in the management of patients with chronic kidney disease, atrial fibrillation, diabetes mellitus, albuminuria, and hyperuricemia.

Hyperuricemia and Atrial Fibrillation

The importance of atrial fibrillation (AF) as a cause of mortality and morbidity has prompted research on its pathogenesis and treatment. Recognition of AF risk factors is essential to prevent it and reduce the risk of death. Hyperuricemia has been widely accepted to be associated with the incidence of paroxysmal or persistent AF, as well as to the risk of AF in post cardiovascular surgery patients. The possible explanations for this association have been based on their relation with either oxidative stress or inflammation. To investigate the link between hyperuricemia and AF, it is necessary to refer to hyperuricemia-induced atrial remodeling. So far, both ionic channel and structural remodeling caused by hyperuricemia might be plausible explanations for the occurrence of AF. Inhibition of xanthine oxidase and nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase, or the use of antioxidants, along with serum uric acid (SUA) level reduction to prevent inflammation, might be useful. Uric acid transporters (UATs) play a key role in the regulation of intracellular uric acid concentration. Intracellular rather than serum uric acid level is considered more important for the pathogenesis of AF. Identification of UATs expressed in cells is thus important, and targeting UATs might become a potential strategy to reduce the risk of hyperuricemia-induced atrial fibrillation.

Angiotensin II antagonists - an assessment of their acute toxicity

OBJECTIVE

In Germany, increasing prescription rates of angiotensin II antagonists resulted in rising enquiries to Poisons Information Centres (PICs) during the last decade. Therefore, we aimed to assess their acute toxicity for deriving triage recommendations.

METHODS

An observational case series with data collected retrospectively from eight PICs in Austria, Germany and Switzerland. Inclusion criteria were monoexposure, defined dose, and documented follow-up.

RESULTS

In total, 206 cases of exposures to angiotensin II antagonists were included (candesartan, 94; eprosartan, 3; irbesartan, 20; losartan, 26; olmesartan, 16; telmisartan, 18; and valsartan, 29). The median dose expressed as a multiple of their maximum daily dose for adults adjusted to body weight (MDDw) was 2.3 in children and 6.8 in adults. Patients involved were 150 children with a median age of 2 years and a median body weight of 13 kg and 56 adults with a median age of 47 years and a median body weight of 70 kg. Most children remained asymptomatic (82.7%), 16.7% developed minor symptoms. Only once, a low blood pressure of 60/40 mm Hg required intravenous fluids after ingestion of a 8.75-fold MDDw of candesartan by a 2.5-year-old toddler. Among adults, 53.6% remained asymptomatic while almost half of the patients suffered from minor (37.5%) or moderate (8.9%) symptoms.

CONCLUSION

As no or only minor symptoms were observed after ingestion of less than a fivefold MDDw in both children and adults, only symptomatic patients and those who have ingested a fivefold MDDw or higher dose should be referred for medical assessment.

Angiotensin II AT(1) receptor blockers as treatments for inflammatory brain disorders

The effects of brain AngII (angiotensin II) depend on AT(1) receptor (AngII type 1 receptor) stimulation and include regulation of cerebrovascular flow, autonomic and hormonal systems, stress, innate immune response and behaviour. Excessive brain AT(1) receptor activity associates with hypertension and heart failure, brain ischaemia, abnormal stress responses, blood-brain barrier breakdown and inflammation. These are risk factors leading to neuronal injury, the incidence and progression of neurodegerative, mood and traumatic brain disorders, and cognitive decline. In rodents, ARBs (AT(1) receptor blockers) ameliorate stress-induced disorders, anxiety and depression, protect cerebral blood flow during stroke, decrease brain inflammation and amyloid-β neurotoxicity and reduce traumatic brain injury. Direct anti-inflammatory protective effects, demonstrated in cultured microglia, cerebrovascular endothelial cells, neurons and human circulating monocytes, may result not only in AT(1) receptor blockade, but also from PPARγ (peroxisome-proliferator-activated receptor γ) stimulation. Controlled clinical studies indicate that ARBs protect cognition after stroke and during aging, and cohort analyses reveal that these compounds significantly reduce the incidence and progression of Alzheimer's disease. ARBs are commonly used for the therapy of hypertension, diabetes and stroke, but have not been studied in the context of neurodegenerative, mood or traumatic brain disorders, conditions lacking effective therapy. These compounds are well-tolerated pleiotropic neuroprotective agents with additional beneficial cardiovascular and metabolic profiles, and their use in central nervous system disorders offers a novel therapeutic approach of immediate translational value. ARBs should be tested for the prevention and therapy of neurodegenerative disorders, in particular Alzheimer's disease, affective disorders, such as co-morbid cardiovascular disease and depression, and traumatic brain injury.

Angiotensin II AT(1) receptor blockers ameliorate inflammatory stress: a beneficial effect for the treatment of brain disorders

Excessive allostatic load as a consequence of deregulated brain inflammation participates in the development and progression of multiple brain diseases, including but not limited to mood and neurodegenerative disorders. Inhibition of the peripheral and brain Renin-Angiotensin System by systemic administration of Angiotensin II AT(1) receptor blockers (ARBs) ameliorates inflammatory stress associated with hypertension, cold-restraint, and bacterial endotoxin administration. The mechanisms involved include: (a) decreased inflammatory factor production in peripheral organs and their release to the circulation; (b) reduced progression of peripherally induced inflammatory cascades in the cerebral vasculature and brain parenchyma; and (c) direct anti-inflammatory effects in cerebrovascular endothelial cells, microglia, and neurons. In addition, ARBs reduce bacterial endotoxin-induced anxiety and depression. Further pre-clinical experiments reveal that ARBs reduce brain inflammation, protect cognition in rodent models of Alzheimer's disease, and diminish brain inflammation associated with genetic hypertension, ischemia, and stroke. The anti-inflammatory effects of ARBs have also been reported in circulating human monocytes. Clinical studies demonstrate that ARBs improve mood, significantly reduce cognitive decline after stroke, and ameliorate the progression of Alzheimer's disease. ARBs are well-tolerated and extensively used to treat cardiovascular and metabolic disorders such as hypertension and diabetes, where inflammation is an integral pathogenic mechanism. We propose that including ARBs in a novel integrated approach for the treatment of brain disorders such as depression and Alzheimer's disease may be of immediate translational relevance.

Blockade of brain angiotensin II AT1 receptors ameliorates stress, anxiety, brain inflammation and ischemia: Therapeutic implications

Poor adaptation to stress, alterations in cerebrovascular function and excessive brain inflammation play critical roles in the pathophysiology of many psychiatric and neurological disorders such as major depression, schizophrenia, post traumatic stress disorder, Parkinson's and Alzheimer's diseases and traumatic brain injury. Treatment for these highly prevalent and devastating conditions is at present very limited and many times inefficient, and the search for novel therapeutic options is of major importance. Recently, attention has been focused on the role of a brain regulatory peptide, Angiotensin II, and in the translational value of the blockade of its physiological AT(1) receptors. In addition to its well-known cardiovascular effects, Angiotensin II, through AT(1) receptor stimulation, is a pleiotropic brain modulatory factor involved in the control of the reaction to stress, in the regulation of cerebrovascular flow and the response to inflammation. Excessive brain AT(1) receptor activity is associated with exaggerated sympathetic and hormonal response to stress, vulnerability to cerebrovascular ischemia and brain inflammation, processes leading to neuronal injury. In animal models, inhibition of brain AT(1) receptor activity with systemically administered Angiotensin II receptor blockers is neuroprotective; it reduces exaggerated stress responses and anxiety, prevents stress-induced gastric ulcerations, decreases vulnerability to ischemia and stroke, reverses chronic cerebrovascular inflammation, and reduces acute inflammatory responses produced by bacterial endotoxin. These effects protect neurons from injury and contribute to increase the lifespan. Angiotensin II receptor blockers are compounds with a good margin of safety widely used in the treatment of hypertension and their anti-inflammatory and vascular protective effects contribute to reduce renal and cardiovascular failure. Inhibition of brain AT(1) receptors in humans is also neuroprotective, reducing the incidence of stroke, improving cognition and decreasing the progression of Alzheimer's disease. Blockade of AT(1) receptors offers a novel and safe therapeutic approach for the treatment of illnesses of increasing prevalence and socioeconomic impact, such as mood disorders and neurodegenerative diseases of the brain.

Effects of losartan on fibrinolytic parameters and von Willebrand factor in Chinese subjects with hypertension: a comparative study versus atenolol

To compare the effects of losartan and atenolol on plasma fibrinolytic parameters and von Willebrand factor (vWF), Chinese subjects with mild-to-moderate hypertension were randomized to receive losartan (50 mg/day; n = 30) or atenolol (50 mg/day; n = 30) for 8 weeks. If target blood pressure (< 140/90 mmHg) was not achieved at week 4, hydrochlorothiazide (12.5 mg/day) was also administered. Plasma levels of tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1) and vWF were determined at baseline and after treatment. Between-group baseline characteristics and blood pressure decrease were comparable. Losartan significantly reduced plasma PAI-1 and vWF and PAI-1/tPA ratio. Atenolol significantly increased plasma tPA, but PAI-1, vWF and PAI-1/tPA ratio were unchanged. In conclusion, losartan, but not atenolol improved the fibrinolytic system and reduced plasma vWF levels in Chinese hypertensives.

The role of RAS modification for primary and secondary stroke prevention

Clinical trial results indicate that the choice of antihypertensive agent can be a determinant of stroke protection, independent of blood pressure (BP) reduction. Angiotensin-converting enzyme inhibitors (ACE-Is) are effective for BP control and stroke protection, but their use may be limited by patient tolerability. Angiotensin receptor blockers appear to provide similar BP control compared with ACE-Is and may also offer the clinician the added benefit of primary and secondary stroke prevention, with the potential for fewer tolerability issues.

Do pleiotropic effects of antihypertensive medications exist or is it all about the blood pressure?

Examination of the large-scale drug-versus-drug trials suggests that the initial drug choice is of token importance and that better blood pressure control is the primary determinant of superior outcomes. In pooled analyses, the achieved blood pressure is similar for older and less expensive drugs, such as thiazide-type diuretics, and for newer and more costly agents, such as angiotensin-converting enzyme inhibitors, -angiotensin-receptor blockers, and calcium-channel blockers. If blood pressure--independent differences favoring one antihypertensive drug class over another truly exist, they have been singularly difficult to uncover with any consistency. Considering that multidrug therapy is required in the majority of patients with hypertension, the debate as to which drug class is best to start with is moot, in that the clinician is now more called upon to decide the best combinations of drugs and not the best monotherapy.

The left atrium, atrial fibrillation, and the risk of stroke in hypertensive patients with left ventricular hypertrophy

The Losartan Intervention For Endpoint reduction in hypertension (LIFE) study provided extensive data on predisposing factors, consequences, and prevention of atrial fibrillation (AF) in patients with hypertension and left ventricular (LV) hypertrophy. Randomized losartan-based treatment was superior to atenolol-based treatment for reducing new-onset AF and complications, especially stroke, associated with new-onset or pre-existing AF. Potential mechanisms of AF prevention by angiotensin receptor blockade supported by LIFE results include greater reduction in left atrial size and LV hypertrophy. Differential effects of antihypertensive treatment on the left atrium and left ventricle may help prevent AF and reduce risk of stroke associated with hypertensive heart disease.

Managing hypertension in cardiology practice according to risk profile

Cardiologists play a central role in managing hypertensive patients, although recent surveys reveal a marked discrepancy between cardiologists' appreciation of their patients' risk status and the measures taken to reduce that risk. The diagnosis and the management of hypertension, in fact, must be viewed today not in isolation, but as part of a patients' global cardiovascular (CV) risk, resulting from the concomitant presence of a variety of risk factors, organ damage (left ventricular hypertrophy, carotid or peripheral atherosclerosis, microalbuminuria or impaired glomerular filtration rate), and hypertension-related clinical conditions. The choice of timing and the intensity of antihypertensive treatment should be based on blood pressure (BP)-lowering efficacy and the propensity to favourably impact patient's individual absolute CV disease risk profile. As part of this paradigm shift in CV disease prevention strategy, cardiologists can take several key steps to help improve standards of hypertension control: (i) increase the awareness of total risk management; (ii) initiate an integrated management strategy tailored to the individual patient's global CV risk (e.g. hypertension, hypercholesterolaemia, diabetes, age, smoking and gender); (iii) use any elevation in BP as a gateway to begin total risk management and (iv) utilise combination therapies (particularly fixed-dose combinations) to achieve more rapid and persistent BP control and improve patient compliance/persistence with therapy. To help improve standards of hypertension control in the cardiology setting, this review examines the concept of treating hypertension using a global risk assessment approach and proposes effective hypertensive therapy as part of global risk management in patients typically seen in cardiology practice.

Molecule-specific effects of angiotensin II-receptor blockers independent of the renin-angiotensin system

Because all clinically approved angiotensin-receptor blockers (ARBs) have good safety profiles and share the ability to block angiotensin II type 1 (AT1) receptors and reduce blood pressure, it is tempting to assume that all ARBs will yield equivalent degrees of cardiovascular protection. However, such a belief depends on the tacit assumption that with appropriate dosing, all ARBs will also share the same ability to counteract other pathogenetic determinants of cardiovascular disease beyond those involving the renin-angiotensin system. Accumulating evidence from multiple laboratories has shown that this assumption is incorrect and indicates that some ARBs are characterized by an unusual ability to affect potential mechanisms of cardiovascular disease involving more than just the renin-angiotensin system. Ultimately, large-scale clinical trials will be required to better understand the clinical importance of the mechanistic effects of ARBs that involve more than just inhibition of the renin-angiotensin system. Meanwhile, given the many functional differences among ARBs that are not mediated by AT1 receptor blockade, the effects of any particular ARB on cardiovascular outcomes should not be assumed to apply equally to all ARBs let alone to other drugs that inhibit the renin-angiotensin system through different mechanisms.

An update on non-peptide angiotensin receptor antagonists and related RAAS modulators

The renin-angiotensin-aldosterone-system (RAAS) is an important regulator of blood pressure and fluid-electrolyte homeostasis. RAAS has been implicated in pathogenesis of hypertension, congestive heart failure, and chronic renal failure. Aliskiren is the first non-peptide orally active renin inhibitor approved by FDA. Angiotensin Converting Enzyme (ACE) Inhibitors are associated with frequent side effects such as cough and angio-oedema. Recently, the role of ACE2 and neutral endopeptidase (NEP) in the formation of an important active metabolite/mediator of RAAS, ang 1-7, has initiated attempts towards development of ACE2 inhibitors and combined ACE/NEP inhibitors. Furukawa and colleagues developed a series of low molecular weight nonpeptide imidazole analogues that possess weak but selective, competitive AT1 receptor blocking property. Till date, many compounds have exhibited promising AT1 blocking activity which cause a more complete RAAS blockade than ACE inhibitors. Many have reached the market for alternative treatment of hypertension, heart failure and diabetic nephropathy in ACE inhibitor intolerant patients and still more are waiting in the queue. But, the hallmark of this area of drug research is marked by a progress in understanding molecular interaction of these blockers at the AT1 receptor and unraveling the enigmatic influence of AT2 receptors on growth/anti-growth, differentiation and the regeneration of neuronal tissue. Different modeling strategies are underway to develop tailor made molecules with the best of properties like Dual Action (Angiotensin And Endothelin) Receptor Antagonists (DARA), ACE/NEP inhibitors, triple inhibitors, AT2 agonists, AT1/TxA2 antagonists, balanced AT1/AT2 antagonists, and nonpeptide renin inhibitors. This abstract gives an overview of these various angiotensin receptor antagonists.