Hemodynamic and neurohormonal effects of the angiotensin II antagonist losartan in patients with congestive heart failure

Guideline-Directed Medical Therapy for the Treatment of Heart Failure with Reduced Ejection Fraction

Guideline-directed medical therapy (GDMT) is the cornerstone of pharmacological therapy for patients with heart failure with reduced ejection fraction (HFrEF) and consists of the four main drug classes: renin-angiotensin system inhibitors, evidence-based β-blockers, mineralocorticoid inhibitors and sodium glucose cotransporter 2 inhibitors. The recommendation for use of GDMT is based on the results of multiple major randomized controlled trials demonstrating improved clinical outcomes in patients with HFrEF who are maintained on this therapy. The effect is most beneficial when medications from the four main drug classes are used in conjunction. Despite this, there is an underutilization of GDMT, partially due to lack of awareness of how to safely and effectively initiate and titrate these medications. In this review article, we describe the different drug classes included in GDMT and offer an approach to initiation and effective titration in both the inpatient as well as outpatient setting.

Drug Treatment of Heart Failure in Children: Gaps and Opportunities

Medical therapy for pediatric heart failure is based on a detailed mechanistic understanding of the underlying causes, which are diverse and unlike those encountered in most adult patients. Diuresis and improved perfusion are the immediate goals of care in the child with acute decompensated heart failure. Conversion to maintenance oral therapy for heart failure is based on the results of landmark studies in adults, as well as recent pediatric clinical trials and heart failure guidelines. There will continue to be an important role for newer drugs, some of which are in active trials in adults, and some of which are already approved for use in children. The need to plan for clinical trials in children during drug development for heart failure is emphasized.

Clinical Characteristics and Inflammatory Immune Responses in COVID-19 Patients With Hypertension: A Retrospective Study

Coronavirus disease (COVID-19) patients with cardiovascular and metabolic disorders have been found to have a high risk of developing severe conditions with high mortality, further affecting the prognosis of COVID-19. However, the effect of hypertension and angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blocker (ARB) agents on the clinical characteristics and inflammatory immune responses in COVID-19 patients is still undefined. In this study, 90 COVID-19 patients were divided into hypertension and nonhypertension groups. The hypertension group was divided into well-controlled and poorly controlled subgroups based on blood pressure levels; moreover, hypertensive patients were also divided into ACEI/ARB and non-ACEI/ARB subgroups according to the administration of ACEI/ARB antihypertensive agents. The clinical characteristics of and inflammatory immune biomarker levels in the different groups of COVID-19 patients were compared, and the association between the combined effect of hypertension with ACEI/ARB antihypertensive agents and the severity of COVID-19 was examined. The results showed that the levels of aminotransferase (AST) and hs-cTnI were higher in the hypertension group compared with the nonhypertension group. The long-term use of ACEI/ARB agents in patients had statistically significantly lower AST, low-density lipoprotein cholesterol (LDL-C), and oxygen uptake and lower white cell count, neutrophil count, and levels of CD4, CD8, CRP, and PCT but without statistical significance. In addition, compared with COVID-19 patients without hypertension, hypertensive patients without the use of ACEI/ARB had a higher risk of developing severity of COVID-19 (for poorly controlled patients: OR = 3.97, 95% CI = 1.03–15.30; for well-controlled patients: OR = 6.48, 95% CI = 1.77–23.81). Hypertension could cause organ damage in COVID-19 patients, but the long-term use of ACEI/ARB agents may be beneficial to alleviate this injury.

Current and Future Drug and Device Therapies for Pediatric Heart Failure Patients: Potential Lessons from Adult Trials

This review discusses the potential drug and device therapies for pediatric heart failure (HF) due to reduced systolic function. It is important to realize that most drugs that are used in pediatric HF are extrapolated from adult cardiology practices or consensus guidelines based on expert opinion rather than on evidence from controlled clinical trials. It is difficult to conclude whether the drugs that are well established in adult HF trials are also beneficial for children because of tremendous heterogeneity in the mechanism of HF in children and variations in the pharmacokinetics and pharmacodynamics of drugs from birth to adolescence. The lessons learned from adult trials can guide pediatric cardiologists to design clinical trials of the newer drugs that are in the pipeline to study their efficacy and safety in children with HF. This paper's focus is that the reader should specifically think through the pathophysiological mechanism of HF and the mode of action of drugs for the selection of appropriate pharmacotherapy. We review the drug and device trials in adults with HF to highlight the knowledge gap that exists in the pediatric HF population.

The structural reconformation of peptides in enhancing functional and therapeutic properties: Insights into their solid state crystallizations

Therapeutic peptides derived proteins with alpha-reconformation states like antibody shape have shown potential effects in combating terrible diseases linked with earlier signs of angiogensis, mutagenesis and transgenesis. Alpha reconformation in material design refers to the folding of the peptide chains and their transitions under reversible chemical bonds of disulfide chemical bridges and further non-covalence lesions. Thus, the rational design of signal peptides into alpha-helix is intended in increasing the defending effects of peptides into cores like adjuvant antibiotic and/or vaccines. Thereby, the signal peptides are able in displaying multiple eradicating regions by changing crystal-depositions and deviation angles. These types of molecular structures could have multiple advantages in tracing disease syndromes and impurities by increasing the host defense against the fates of pathogens and viruses, eventually leading to the loss in signaling by increasing peptide susceptibility levels to folding and unfolding and therefore, formation of transgenic peptide models. Alpha reconformation peptides is aimed in triggering as well as other regulatory functions such as remodulating metabolic chain disorders of lipolysis and glucolysis by increasing the insulin and leptin resistance for best lipid storages and lipoprotein density distributions.

Association between serum 25-hydroxyvitamin D and the effects of Angiotensin II receptor blocker on renal function among African Americans: A post hoc analysis of a randomized placebo-controlled trial

We tested the hypothesis that vitamin D status may modify the effect of Angiotensin II receptor blocker (ARB) on renal function among African Americans. Sixty-four participants were included in this ancillary study from a randomized, double-blind, placebo-controlled, crossover trial among normotensive African Americans to test the effect of ARB on stress response of blood pressure and renal sodium handling. The participants were randomly assigned to receive either ARB or placebo for one week, washed out for one week and then cross-overed to receive the other intervention for one week. On the final day of each intervention, the participant underwent a mental stress test. Baseline serum 25-hydroxyvitamin D [25(OH)D] level was measured in this ancillary study. Sixty-four participants were included, aged 26.5 ± 10.2 years and 47% were female. Among the participants with the serum 25(OH)D concentrations in the low tertile, ARB treatment was associated with 2.58 mg/dL higher blood urea nitrogen (BUN) (P < .001) and was not associated with serum creatinine (SCr) or estimated glomerular filtration rate (eGFR) (Ps > .05). Among the participants in the high 25(OH)D tertile, ARB was associated with 1.59 mg/dL lower BUN (P < .001), 0.08 mg/dL lower SCr (P = .001), and 8.59 mL/min/1.73 m² higher eGFR (P = .001). The interactions between vitamin D and ARB on renal function were more significant during stress and recovery than at rest. The effects of ARB treatment on renal function are modified by the vitamin D status among African Americans. ARB may improve renal function only among the ones with optimal vitamin D status.

Cardiac Regeneration After Myocardial Infarction: an Approachable Goal

Purpose of Review

Until recently, cardiac regeneration after myocardial infarction has remained a holy grail in cardiology. Failure of clinical trials using adult stem cells and scepticism about the actual existence of such cells has reinforced the notion that the heart is an irreversibly post-mitotic organ. Recent evidence has drastically challenged this conclusion.

Recent Findings

Cardiac regeneration can successfully be obtained by at least two strategies. First, new cardiomyocytes can be generated from embryonic stem cells or induced pluripotent stem cells and administered to the heart either as cell suspensions or upon ex vivo generation of contractile myocardial tissue. Alternatively, the endogenous capacity of cardiomyocytes to proliferate can be stimulated by the delivery of individual genes or, more successfully, of selected microRNAs.

Summary

Recent experimental success in large animals by both strategies now fuels the notion that cardiac regeneration is indeed possible. Several technical hurdles, however, still need to be addressed and solved before broad and successful clinical application is achieved.

Angiotensin II receptor I blockade prevents stenosis of tissue engineered vascular grafts

We previously developed a tissue-engineered vascular graft (TEVG) made by seeding autologous cells onto a biodegradable tubular scaffold, in an attempt to create a living vascular graft with growth potential for use in children undergoing congenital heart surgery. Results of our clinical trial showed that the TEVG possesses growth capacity but that its widespread clinical use is not yet advisable due to the high incidence of TEVG stenosis. In animal models, TEVG stenosis is caused by increased monocytic cell recruitment and its classic ("M1") activation. Here, we report on the source and regulation of these monocytes. TEVGs were implanted in wild-type, CCR2 knockout ( Ccr2-/-), splenectomized, and spleen graft recipient mice. We found that bone marrow-derived Ly6C+hi monocytes released from sequestration by the spleen are the source of mononuclear cells infiltrating the TEVG during the acute phase of neovessel formation. Furthermore, short-term administration of losartan (0.6 g/L, 2 wk), an angiotensin II type 1 receptor antagonist, significantly reduced the macrophage populations (Ly6C+/-/F480+) in the scaffolds and improved long-term patency in TEVGs. Notably, the combined effect of bone marrow-derived mononuclear cell seeding with short-term losartan treatment completely prevented the development of TEVG stenosis. Our results provide support for pharmacologic treatment with losartan as a strategy to modulate monocyte infiltration into the grafts and thus prevent TEVG stenosis.-Ruiz-Rosado, J. D. D., Lee, Y.-U., Mahler, N., Yi, T., Robledo-Avila, F., Martinez-Saucedo, D., Lee, A. Y., Shoji, T., Heuer, E., Yates, A. R., Pober, J. S., Shinoka, T., Partida-Sanchez, S., Breuer, C. K. Angiotensin II receptor I blockade prevents stenosis of tissue engineered vascular grafts.

Acute effects of angiotensin-converting enzyme inhibition versus angiotensin II receptor blockade on cardiac sympathetic activity in patients with heart failure

The beneficial effects of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II (ANG II) receptor antagonists in patients with heart failure secondary to reduced ejection fraction (HFrEF) are felt to result from prevention of the adverse effects of ANG II on systemic afterload and renal homeostasis. However, ANG II can activate the sympathetic nervous system, and part of the beneficial effects of ACE inhibitors and ANG II antagonists may result from their ability to inhibit such activation. We examined the acute effects of the ACE inhibitor captopril (25 mg, n = 9) and the ANG II receptor antagonist losartan (50 mg, n = 10) on hemodynamics as well as total body and cardiac norepinephrine spillover in patients with chronic HFrEF. Hemodynamic and neurochemical measurements were made at baseline and at 1, 2, and 4 h after oral dosing. Administration of both drugs caused significant reductions in systemic arterial, cardiac filling, and pulmonary artery pressures (P < 0.05 vs. baseline). There was no significant difference in the magnitude of those hemodynamic effects. Plasma concentrations of ANG II were significantly decreased by captopril and increased by losartan (P < 0.05 vs. baseline for both). Total body sympathetic activity increased in response to both captopril and losartan (P < 0.05 vs. baseline for both); however, there was no change in cardiac sympathetic activity in response to either drug. The results of the present study do not support the hypothesis that the acute inhibition of the renin-angiotensin system has sympathoinhibitory effects in patients with chronic HFrEF.

Pharmacologic Management of Chronic Heart Failure: A Review

Standard drug therapy of systolic heart failure has been evaluated in large-scale randomized clinical trials and includes angiotensin-converting enzyme (ACE) inhibi tors, which should be used as first-line therapy, diuret ics for the management of extracellular fluid volume excess, and digoxin. In combination with ACE inhibitors and diuretics, with or without digoxin, some β-adrener gic receptor blockers attenuate disease progression and improve outcome in mild-to-moderate systolic heart failure. The pharmacologic management of chronic dia stolic heart failure is largely empirical and directed at reducing symptoms. Symptoms caused by increased ventricular filling pressures may be diminished by diuret ics and nitrovasodilators. Some calcium channel antago nists and most β-blockers prolong diastolic filling time by slowing heart rate, thereby improving the symptoms of diastolic heart failure.

Short-Term Angiotensin Subtype 1 Receptor Blockade Does Not Alter the Circulatory Responses to Sympathetic Nervous System Modulation in Healthy Volunteers Before and During Sevoflurane Anesthesia: Results of a Pilot Study

OBJECTIVE

The mechanism of perioperative hypotension in patients taking an angiotensin-receptor blocker up to the time of surgery remains unclear. This study tested the hypothesis that short-term angiotensin-receptor blocker treatment attenuated the sympathetic and vascular responses to autonomic stimuli in volunteers undergoing anesthesia.

DESIGN

Randomized, crossover, blinded, pilot design.

SETTING

Zablocki Veterans Affairs Medical Center, Milwaukee, WI.

PARTICIPANTS

The study comprised 8 male and 6 female healthy, young volunteers (age 23±1.2 years [mean±standard error of the mean]).

INTERVENTIONS

Volunteers were studied after receiving oral placebo or 50 mg of losartan (angiotensin-receptor blocker) for 3 days before each test day. The effectiveness of angiotensin-receptor blocker treatment was confirmed using the mean arterial blood pressure response to intravenous angiotensin II (1-µg bolus). Eight volunteers underwent direct mean arterial pressure and forearm bloodflow measurements during conscious baseline, a cold pressor test, induction of anesthesia, tracheal intubation, maintenance of anesthesia with 1 minimum alveolar concentration of sevoflurane, and airway irritation with 12% desflurane. Six volunteers experienced mean arterial pressure responses to 0.1 mg of phenylephrine at baseline and during 1 minimum alveolar concentration of sevoflurane.

MEASUREMENTS AND MAIN RESULTS

Comparisons were made over time and across groups. Angiotensin-receptor blocker treatment significantly reduced-mean arterial pressure and forearm vascular resistance (forearm blood flow/mean arterial pressure) over time and blocked the mean arterial pressure response to angiotensin-II challenge. The changes in mean arterial pressure and forearm vascular resistance in response to all stressors did not differ between treatments. Mean arterial pressure increases from phenylephrine were preserved.

CONCLUSIONS

In healthy, young volunteers, sympathetically-mediated responses from the short-term use of an angiotensin-receptor blocker were not altered and most likely did not contribute to perioperative hypotension during the intraoperative period.

Impaired neuronal and vascular responses to angiotensin II in a rabbit congestive heart failure model

Congestive heart failure (CHF) is characterised by activation of the renin-angiotensin-aldosterone system (RAAS) and the sympathetic nervous system (SNS). Both systems are known to interact and to potentiate each other's activities. We recently demonstrated that angiotensin II (Ang II) enhances sympathetic nerve traffic via prejunctionally-located AT1-receptors. At present, little is known about the effects of Ang II at the level of the sympathetic neurones in CHF.

Accordingly, we investigated the effect of Ang II in the presence and absence of the AT1-receptor antagonist, eprosartan, on stimulation-induced nerve traffic in isolated thoracic aorta preparations obtained from rabbits suffering from experimentally-induced CHF. Control-preparations were obtained from age-matched animals. Sympathetic activity was assessed by a [3H]noradrenaline spill-over model. Additionally, Ang II constrictor responses were compared between CHF and control vessels in the presence and absence of eprosartan. Additionally, to study postjunctional facilitation, the effects of Ang II on postsynaptic α-adrenoceptor-mediated responses were studied using noradrenaline.

Stimulation-evoked SNS-neurotransmission was similar in both groups (CHF versus control). Ang II (0.1 nM—0.1 µM) caused a concentration-dependent increase of the stimulation-evoked sympathetic outflow in both groups, with a maximum at 10 nM (control [n=7], FR2/FR12.03±0.11 and CHF-preparations [n=7], FR2/FR11.71±0.07). The enhancement by Ang II was decreased in CHF-preparations compared with controls (p<0.05). Eprosartan concentration-dependently attenuated the Ang II-enhanced (10 nM) sympathetic outflow in both CHF- and control preparations. The sympathoinhibitory potency of eprosartan was similar in both groups (control pIC508.81±0.31; CHF 8.65±0.42).

Ang II (1 nM—0.3 µM) concentration-dependently increased the contractile force in control preparations (Emax21.64±3.86 mN, pD27.63±0.02, n=7). Eprosartan (1 nM—0.1 µM) influenced the Ang IIcontractions via a mixed form of antagonism. In CHF-preparations, Ang II caused impaired vascular contraction. The KCl-induced contraction was decreased in the CHF- compared with control preparations (13.02±0.64 mN versus 30.40±0.89 mN). The relative Ang II contraction (% of KCl) was also decreased (2.3% vs. 58.0%). Concentration-response curves to noradrenaline (%KCl) were similar (control pD26.93±0.05, Emax131.0±2.7; CHF pD27.00±0.05, Emax136.7±2.6) (p>0.05) and were not affected by Ang II.

We conclude that Ang II-enhanced sympathetic neurotransmission is mediated by the prejunctional AT1-receptor in both control and CHF-preparations. The decreased facilitation of SNS effects by Ang II may be explained by down-regulation or desensitisation of the neuronal AT1-receptor. Additionally, the aortic contractile capacity in heart failure rabbits appears to be decreased, probably as a result of heart failure-associated neuroendocrine and functional changes.

Harnessing the microRNA pathway for cardiac regeneration

Mounting evidence over the last few years has indicated that the rate of cardiomyocyte proliferation, and thus the extent of cardiac renewal, is under the control of the microRNA network. Several microRNAs (e.g. miR-1) regulate expansion of the cardiomyocyte pool and its terminal differentiation during the embryonic life; some not only promote cardiomyocyte proliferation but also their de-differentiation towards an embryonic cell phenotype (e.g. the miR-302/367 cluster); a few others are involved in the repression of cardiomyocyte proliferation occurring suddenly after birth (e.g. the miR-15 family); others again are not physiologically involved in the regulation of cardiomyocyte turnover, but nevertheless are able to promote cardiomyocyte proliferation and cardiac regeneration when delivered exogenously (e.g. miR-199a-3p). With a few exceptions, the molecular mechanisms underlying the pro-proliferative effect of these microRNAs, most of which appear to act at the level of already differentiated cardiomyocytes, remain to be thoroughly elucidated. The possibility of harnessing the miRNA network to achieve cardiac regeneration paves the way to exciting therapeutic applications. This could be achieved by either administering miRNA mimics or inhibitors, or transducing the heart with viral vectors expressing miRNA-encoding genes.

Summertime dosage-dependent hypersensitivity to an angiotensin II receptor blocker

Background

Summertime dips in blood pressure (BP), both in normotensive and hypertensive subjects, are well known. However, the dips are small and are not related to particular forms or doses of antihypertensive medication. Nevertheless it is the practice in some quarters to decrease antihypertensive medication in summer, and/or to increase in winter. Large scale studies being inconclusive, there are calls for long-term examination of the relationship between environmental temperature and blood pressure in single individuals under medication.

Case presentation

While analyzing data from a subject whose BP had been controlled for a decade with the angiotensin-II receptor blocker losartan, an extreme, dosage-dependent, summertime dip came to light. Downward dosage adjustment appeared essential and may have prevented hypotension-related pathology.

Conclusion

The benefits of aggressive medication (the “J curve” phenomenon) being debated, the possibility of seasonal hypersensitivity, perhaps explicable in terms of differential signaling by countervailing receptors, should be taken into account when considering dosage adjustments in hypertensive subjects.

Angiotensin II type I receptor blockade attenuates reflex cutaneous vasoconstriction in aged but not young skin

Stimulation of angiotensin II type I receptors (AT1R) elicits vasoconstriction (VC) that may be occurring through the activation of a pathogenic vascular pathway such as Rho kinase (ROCK). We hypothesize that reflex cutaneous VC to whole body cooling (mean skin temperature = 30.5°C) in older humans relies in part on AT1R activation, which may explain greater ROCK activity attendant with aging. Two microdialysis (MD) fibers were placed in the forearm skin of 10 young (Y; 24 ± 1 yr) and 10 older (O; 70 ± 2 yr) individuals for infusion of 1) lactated Ringer's solution (switched to fasudil, a ROCK antagonist, after cooling); and 2) AT1R blockade with losartan. Laser Doppler flux (LDF) was measured over each MD site and cutaneous vascular conductance (CVC) was calculated (CVC = LDF/mean arterial pressure) and expressed as percent change from baseline (%ΔCVCBASELINE). In older individuals the VC response to whole body cooling was blunted (Y = −34 ± 2, O = −17 ± 3%ΔCVC) and was further attenuated at the losartan site (Y = −34 ± 3, O = −9 ± 3%ΔCVC; P < 0.05). The VC response to an exogenous 10-μM dose of angiotensin II (Y = −27 ± 3, O = −42 ± 5%ΔCVC) was completely blocked in sites pretreated with losartan or with fasudil. These data suggest that AT1R activation contributes to the reflex VC response in aged but not young skin. Furthermore, the angiotensin II component of the VC response appears to occur primarily through a ROCK-mediated mechanism.

Efficacy and safety of angiotensin receptor blockers in older patients: a meta-analysis of randomized trials

BACKGROUND

The efficacy and safety of angiotensin receptor blockers (ARBs) in the older population is unclear.

OBJECTIVES

To determine the efficacy and safety of ARBs in older patients.

METHODS

Randomized trials that compared ARBs to control and reported clinical outcomes in patients with a mean age of 65 years or older were included. Random-effects summary risk ratios (RRs) were constructed.

RESULTS

A total of 16 trials met our selection criteria, which yielded 113,386 patients. ARBs were associated with a marginal increased risk of all-cause mortality (RR: 1.03, 95% confidence interval (CI): 1.00-1.06, P = 0.05), a nonsignificant increased risk of myocardial infarction (RR: 1.04, 95% CI: 0.96-1.12, P = 0.36), a marginal reduction in heart failure hospitalization (RR: 0.86, 95% CI: 0.74-1.00, P = 0.06), and a significant reduction in the risk of stroke (RR: 0.93, 95% CI: 0.87-0.99, P = 0.03). ARBs were associated with an increased risk of acute kidney injury (RR: 1.48, 95% CI: 1.24-1.77, P < 0.001), hypotension (RR: 1.56, 95% CI: 1.24-1.97, P < 0.001), and hyperkalemia (RR: 1.57, 95% CI: 1.13-2.19, P = 0.008). On the sensitivity analysis including placebo-controlled trials, the risk of all-cause mortality was no longer significant (P = 0.2), while the remainder of the outcomes did not change.

CONCLUSION

In older patients, the benefit of ARBs compared with control was strongest for stroke reduction, with no (or weak) associations for all-cause mortality, myocardial infarction, and heart failure hospitalization. Benefit was offset by an increased risk of acute kidney injury, hypotension, and hyperkalemia. Thus, ARBs should be used with caution in older patients when clinically indicated.