Beta-Blockers in the Management of Hypertension and/or Chronic Kidney Disease

Structure optimization of Cmpd-15 as negative allosteric modulators for the β2-adrenergic receptor

19 derivatives of 1-benzyl-3-arylpyrazole-5-carboxamides (H1-H19) and 5 derivatives of 1-benzyl-5-arylpyrazole-3-carboxamides (J1-J5) have been designed and synthesized as potential negative allosteric modulators (NAMs) for the β2-adrenergic receptor (β2AR). The new pyrazole derivatives were screened on the classic G-protein dependent signaling pathway at β2AR. The majority of 1-benzyl-3-aryl-pyrazole-5-carboxamide derivatives show more potent allosteric antagonistic activity against β2AR than Cmpd-15, the first reported β2AR NAM. However, the 1-benzyl-5-arylpyrazole-3-carboxamide derivatives exhibit very poor or even no allosteric antagonistic activity for β2AR. Furthermore, the active pyrazole derivatives have relative better drug-like profiles than Cmpd-15. Taken together, we discovered a series of derivatives of 1-benzyl-3-arylpyrazole-5-carboxamides as a novel scaffold of β2AR NAM.

Pattern, frequency and factors associated with inappropriate high dosing in chronic kidney disease patients at a tertiary care hospital in Pakistan

BACKGROUND

Patients with chronic kidney diseases (CKD) are susceptible to the toxic drug effects if given unadjusted doses. Although Pakistan harbors a high burden of CKD patients, there is limited information available on the frequency, pattern and factors associated with unadjusted drug doses among CKD patients.

METHODS

This cross-sectional study conducted at Sandeman Provincial Hospital, Quetta included 303 non-dialysis ambulatory CKD patients (glomerular filtration rate < 60 ml/min/1.73m²). The patients' data were collected through a purpose designed data collection form. The appropriateness of doses was checked against the renal drug handbook-2018, Kidney Disease Improving Global Outcomes guidelines, British National Formulary-2022, and manufacturer leaflets. Data were analysed by SPSS 23 and multiple binary logistic regression analysis was used to assess the factors associated with receiving inappropriate high doses. A p-value < 0.05 was considered statistically significant.

RESULTS

The patients received a total of 2265 prescription lines, with a median of eight different drugs per patient (interquartile range: 6-9 drugs). A total of 34.5% (783/2265) drugs required dose adjustment. Of these, doses were not adjusted for 56.1% (440) drugs in 162 (53.4%) patients. The most common pharmacological class of drugs requiring dose adjustment were antibiotics (79.1%), followed by antidiabetics (59.2%), diuretics (57.0%), angiotensin converting enzyme inhibitors (56.9%), beta blockers (56.9%), analgesics (56.0%), angiotensin receptor blockers (55.2%), domperidone (53.9%) and antihyperlipidmics (46.1%). Patient's age of 41-60 (OR = 5.76) and > 60 years (OR = 9.49), hypertension (OR = 2.68), diabetes mellitus (OR = 3.47) and cardiovascular diseases (OR = 2.82) had statistically significant association (p-value < 0.05) with inappropriate high doses.

CONCLUSION

The high frequency of inappropriate high doses suggests an important quality gap in medication dosing for patients with ND-CKD at the study site. Special attention should be paid to the drugs and patients with identified risk factors for receiving inappropriate high doses.

Reno protective role of amlodipine in patients with hypertensive chronic kidney disease

Chronic kidney disease (CKD) and hypertension (HTN) are closely associated with an overlapping and intermingled cause and effect relationship. Decline in renal functions are usually associated with a rise in blood pressure (BP), and prolonged elevations in BP hasten the progression of kidney function decline. Regulation of HTN by normalizing the BP in an individual, thereby slowing the progression of kidney disease and reducing the risk of cardiovascular disease, can be effectively achieved by the anti-hypertensive use of calcium channel blockers (CCBs). Use of dihydropyridine CCBs such as amlodipine (ALM) in patients with CKD is an attractive option not only for controlling BP but also for safely improving patient outcomes. Vast clinical experiences with its use as monotherapy and/or in combination with other anti-hypertensives in varied conditions have demonstrated its superior qualities in effectively managing HTN in patients with CKD with minimal adverse effects. In comparison to other counterparts, ALM displays robust reduction in risk of cardiovascular endpoints, particularly stroke, and in patients with renal impairment. ALM with its longer half-life displays effective BP control over 24-h, thereby reducing the progression of end-stage-renal disease. In conclusion, compared to other classes of CCBs, ALM is an attractive choice for effectively managing HTN in CKD patients and improving the overall quality of life.

Beta-blocker/ACE inhibitor therapy differentially impacts the steady state signaling landscape of failing and non-failing hearts

Heart failure is a multifactorial disease that affects an estimated 38 million people worldwide. Current pharmacotherapy of heart failure with reduced ejection fraction (HFrEF) includes combination therapy with angiotensin-converting enzyme inhibitors (ACEi) and β-adrenergic receptor blockers (β-AR blockers), a therapy also used as treatment for non-cardiac conditions. Our knowledge of the molecular changes accompanying treatment with ACEi and β-AR blockers is limited. Here, we applied proteomics and phosphoproteomics approaches to profile the global changes in protein abundance and phosphorylation state in cardiac left ventricles consequent to combination therapy of β-AR blocker and ACE inhibitor in HFrEF and control hearts. The phosphorylation changes induced by treatment were profoundly different for failing than for non-failing hearts. HFrEF was characterized by profound downregulation of mitochondrial proteins coupled with derangement of β-adrenergic and pyruvate dehydrogenase signaling. Upon treatment, phosphorylation changes consequent to HFrEF were reversed. In control hearts, treatment mainly led to downregulation of canonical PKA signaling. The observation of divergent signaling outcomes depending on disease state underscores the importance of evaluating drug effects within the context of the specific conditions present in the recipient heart.

The β-arrestin-biased β-adrenergic receptor blocker carvedilol enhances skeletal muscle contractility

A decrease in skeletal muscle strength and functional exercise capacity due to aging, frailty, and muscle wasting poses major unmet clinical needs. These conditions are associated with numerous adverse clinical outcomes including falls, fractures, and increased hospitalization. Clenbuterol, a β₂-adrenergic receptor (β₂AR) agonist enhances skeletal muscle strength and hypertrophy; however, its clinical utility is limited by side effects such as cardiac arrhythmias mediated by G protein signaling. We recently reported that clenbuterol-induced increases in contractility and skeletal muscle hypertrophy were lost in β-arrestin 1 knockout mice, implying that arrestins, multifunctional adapter and signaling proteins, play a vital role in mediating the skeletal muscle effects of β₂AR agonists. Carvedilol, classically defined as a βAR antagonist, is widely used for the treatment of chronic systolic heart failure and hypertension, and has been demonstrated to function as a β-arrestin-biased ligand for the β₂AR, stimulating β-arrestin-dependent but not G protein-dependent signaling. In this study, we investigated whether treatment with carvedilol could enhance skeletal muscle strength via β-arrestin-dependent pathways. In a murine model, we demonstrate chronic treatment with carvedilol, but not other β-blockers, indeed enhances contractile force in skeletal muscle and this is mediated by β-arrestin 1. Interestingly, carvedilol enhanced skeletal muscle contractility despite a lack of effect on skeletal muscle hypertrophy. Our findings suggest a potential unique clinical role of carvedilol to stimulate skeletal muscle contractility while avoiding the adverse effects with βAR agonists. This distinctive signaling profile could present an innovative approach to treating sarcopenia, frailty, and secondary muscle wasting.

β-arrestin 1 regulates β2-adrenergic receptor-mediated skeletal muscle hypertrophy and contractility

BACKGROUND

β₂-adrenergic receptors (β₂ARs) are the target of catecholamines and play fundamental roles in cardiovascular, pulmonary, and skeletal muscle physiology. An important action of β₂AR stimulation on skeletal muscle is anabolic growth, which has led to the use of agonists such as clenbuterol by athletes to enhance muscle performance. While previous work has demonstrated that β₂ARs can engage distinct signaling and functional cascades mediated by either G proteins or the multifunctional adaptor protein, β-arrestin, the precise role of β-arrestin in skeletal muscle physiology is not known. Here, we tested the hypothesis that agonist activation of the β₂AR by clenbuterol would engage β-arrestin as a key transducer of anabolic skeletal muscle growth.

METHODS

The contractile force of isolated extensor digitorum longus muscle (EDL) and calcium signaling in isolated flexor digitorum brevis (FDB) fibers were examined from the wild-type (WT) and β-arrestin 1 knockout mice (βarr1KO) followed by chronic administration of clenbuterol (1 mg/kg/d). Hypertrophic responses including fiber composition and fiber size were examined by immunohistochemical imaging. We performed a targeted phosphoproteomic analysis on clenbuterol stimulated primary cultured myoblasts from WT and βarr1KO mice. Statistical significance was determined by using a two-way analysis with Sidak's or Tukey's multiple comparison test and the Student's t test.

RESULTS

Chronic administration of clenbuterol to WT mice enhanced the contractile force of EDL muscle and calcium signaling in isolated FDB fibers. In contrast, when administered to βarr1KO mice, the effect of clenbuterol on contractile force and calcium influx was blunted. While clenbuterol-induced hypertrophic responses were observed in WT mice, this response was abrogated in mice lacking β-arrestin 1. In primary cultured myoblasts, clenbuterol-stimulated phosphorylation of multiple pro-hypertrophy proteins required the presence of β-arrestin 1.

CONCLUSIONS

We have identified a previously unappreciated role for β-arrestin 1 in mediating β₂AR-stimulated skeletal muscle growth and strength. We propose these findings could have important implications in the design of future pharmacologic agents aimed at reversing pathological conditions associated with skeletal muscle wasting.

Relaxant and vasoprotective effects of ginger extracts on porcine coronary arteries

Ginger (Zingiber officinale Roscoe) is a popular Chinese herbal medicine, which is considered to warm the stomach and dispel cold in traditional Chinese medicine. Ginger is widely used to treat stomach disorders, and it has been reported to exhibit antithrombotic activity via the inhibition of platelet aggregation and thromboxane B2 production in vitro. Cardiovascular disease is associated with the aberrant functioning of the heart and circulatory system; the relatively narrow vessels of the circulation are commonly affected and blocked by atherosclerosis, which may result in angina or heart attack. Numerous drugs and medicines are used to treat myocardial infarction; however, they are often associated with numerous side effects. Therefore, it is important to identify substitutive drugs with no unbearable side effects. In the present study, the relaxant effects of ginger crude extract (GCE) were determined on porcine coronary arteries. The DPPH radical scavenging assay, lucigenin‑enhanced chemiluminescence assay and western blot analysis were used to individually detect antioxidant assay of ginger extraction or superoxide anion produced by endothelial cells and molecular signaling. The results indicated that GCE induced relaxation of porcine coronary arteries in an endothelium‑dependent manner. GCE increased vasoprotection via the suppression of nitric oxide synthase and cyclooxygenase. In addition, GCE possessed antioxidant ability, as determined using 1,1‑diphenyl‑2‑picrylhydrazyl and lucigenin‑enhanced chemiluminescence assays. Taken together, the present study demonstrated that GCE exerts marked vasoprotective effects and free radical‑scavenging activities in porcine coronary arteries.

Combination of β Adrenergic Receptor Block and Renin-Angiotensin System Inhibition Diminished the Angiotensin II-Induced Vasoconstriction and Increased Bradykinin-Induced Vasodilation in Hypertension

In hypertension, the combination therapy is frequently used to obtain a better therapeutic effect and reduce adverse effects. One effective combination is with inhibitors and β-blockers of renin–angiotensin system. Although the mechanisms of action of each drug are already known, the antihypertensive mechanism is more complex and therefore the combined treatment mechanism is unclear. Specifically, the effect of the treatments of angiotensin-converting enzyme inhibitor or AT₁ receptor antagonist with β-blocker on the angiotensin II and bradykinin reactivity has not been studied. For this reason, we evaluated the interaction between propranolol and captopril or losartan on vascular reactivity to bradykinin and angiotensin II in spontaneously hypertensive rat. We constructed concentration–response curves to angiotensin II and bradykinin after treatment of SHR with propranolol–captopril or propranolol–losartan by using rat aortic rings. While losartan or captopril with propranolol potentiated bradykinin-induced vasodilation effect, the propranolol–losartan interaction decreased the angiotensin II-induced vasoconstriction. In addition, the combinations did not reduce the heart rate significantly. These results suggest that the combined therapy decreased blood pressure to normotensive values and showed less effect for angiotensin II and greater effect for bradykinin than monotherapy which could contribute in the antihypertensive effect.

Blood pressure and antihypertensive medication profile in a multiethnic Asian population of stable chronic kidney disease patients

INTRODUCTION

Clinical practice guidelines recommend different blood pressure (BP) goals for chronic kidney disease (CKD) patients. Usage of antihypertensive medication and attainment of BP targets in Asian CKD patients remain unclear. This study describes the profile of antihypertensive agents used and BP components in a multiethnic Asian population with stable CKD.

METHODS

Stable CKD outpatients with variability of serum creatinine levels < 20%, taken > 3 months apart, were recruited. Mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using automated manometers, according to practice guidelines. Serum creatinine was assayed and the estimated glomerular filtration rate (GFR) calculated using the CKD Epidemiology Collaboration equation. BP and antihypertensive medication profile was examined using univariate analyses.

RESULTS

613 patients (55.1% male; 74.7% Chinese, 6.4% Indian, 11.4% Malay; 35.7% diabetes mellitus) with a mean age of 57.8 ± 14.5 years were recruited. Mean SBP was 139 ± 20 mmHg, DBP was 74 ± 11 mmHg, serum creatinine was 166 ± 115 µmol/L and GFR was 53 ± 32 mL/min/1.73 m(2). At a lower GFR, SBP increased (p < 0.001), whereas DBP decreased (p = 0.0052). Mean SBP increased in tandem with the number of antihypertensive agents used (p < 0.001), while mean DBP decreased when ≥ 3 antihypertensive agents were used (p = 0.0020).

CONCLUSION

Different targets are recommended for each BP component in CKD patients. A majority of patients cannot attain SBP targets and/or exceed DBP targets. Research into monitoring and treatment methods is required to better define BP targets in CKD patients.

Allosteric "beta-blocker" isolated from a DNA-encoded small molecule library

The β₂-adrenergic receptor (β₂AR) has been a model system for understanding regulatory mechanisms of G-protein-coupled receptor (GPCR) actions and plays a significant role in cardiovascular and pulmonary diseases. Because all known β-adrenergic receptor drugs target the orthosteric binding site of the receptor, we set out to isolate allosteric ligands for this receptor by panning DNA-encoded small-molecule libraries comprising 190 million distinct compounds against purified human β₂AR. Here, we report the discovery of a small-molecule negative allosteric modulator (antagonist), compound 15 [([4-((2S)-3-(((S)-3-(3-bromophenyl)-1-(methylamino)-1-oxopropan-2-yl)amino)-2-(2-cyclohexyl-2-phenylacetamido)-3-oxopropyl)benzamide], exhibiting a unique chemotype and low micromolar affinity for the β₂AR. Binding of 15 to the receptor cooperatively enhances orthosteric inverse agonist binding while negatively modulating binding of orthosteric agonists. Studies with a specific antibody that binds to an intracellular region of the β₂AR suggest that 15 binds in proximity to the G-protein binding site on the cytosolic surface of the β₂AR. In cell-signaling studies, 15 inhibits cAMP production through the β₂AR, but not that mediated by other Gs-coupled receptors. Compound 15 also similarly inhibits β-arrestin recruitment to the activated β₂AR. This study presents an allosteric small-molecule ligand for the β₂AR and introduces a broadly applicable method for screening DNA-encoded small-molecule libraries against purified GPCR targets. Importantly, such an approach could facilitate the discovery of GPCR drugs with tailored allosteric effects.

Nebivolol Effects on Nitric Oxide Levels, Blood Pressure, and Renal Function in Kidney Transplant Patients

In hypertensive kidney transplant recipients, the effects of nebivolol vs metoprolol on nitric oxide (NO) blood level, estimated glomerular filtration rate (eGFR), and blood pressure (BP) have not been previously reported. In a 12-month prospective, randomized, open-label, active-comparator trial, hypertensive kidney transplant recipients were treated with nebivolol (n=15) or metoprolol (n=15). Twenty-nine patients (nebivolol [n=14], metoprolol [n=15]) completed the trial. The primary endpoint was change in blood NO level after 12 months of treatment. Secondary endpoints were changes in eGFR, BP, and number of antihypertensive drug classes used. After 12 months of treatment, least squares mean change in plasma NO level in the nebivolol kidney transplant recipient group younger than 50 years was higher by 68.19% (99.17% confidence interval [CI], 13.02-123.36), 69.54% (99.17% CI, 12.71-126.37), and 66.80% (99.17% CI, 12.95-120.64) compared with the metoprolol group younger than 50 years, the metoprolol group 50 years and older, and the nebivolol group 50 years and older, respectively. The baseline to month 12 change in mean arterial BP, eGFR, and number of antihypertensive drug classes used was not significantly different between the treatment groups. In hypertensive kidney transplant recipients, nebivolol use in patients younger than 50 years increased blood NO.

Beta-Blocker Use Is Associated with Higher Renal Tissue Oxygenation in Hypertensive Patients Suspected of Renal Artery Stenosis

BACKGROUND

Chronic renal hypoxia influences the progression of chronic kidney disease (CKD). Blood oxygen level-dependent (BOLD) magnetic resonance (MR) is a noninvasive tool for the assessment of renal oxygenation. The impact of beta-blockers on renal hemodynamics and oxygenation is not completely understood. We sought to determine the association between beta-blocker use, renal cortical and medullary oxygenation, and renal blood flow in patients suspected of renal artery stenosis.

METHODS

We measured renal cortical and medullary oxygenation using BOLD MR and renal artery blood flow using MR phase contrast techniques in 38 participants suspected of renal artery stenosis.

RESULTS

Chronic beta-blocker therapy was associated with improved renal cortical (p < 0.001) and medullary (p = 0.03) oxygenation, while the use of calcium channel blockers or diuretics showed no association with either cortical or medullary oxygenation. Receipt of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers was associated with reduced medullary oxygenation (p = 0.01). In a multivariable model, chronic receipt of beta-blockers was the only significant predictor of renal tissue oxygenation (β = 8.4, p = 0.008). Beta-blocker therapy was not associated with significant changes in renal artery blood flow, suggesting that improved renal oxygenation may be related to reduced renal oxygen consumption.

CONCLUSIONS

In addition to known benefits to reduce cardiovascular mortality in patients with renal disease, beta-blockers may reduce or prevent the progression of renal dysfunction in patients with hypertension, diabetes, and renovascular disease, partly by reducing renal oxygen consumption. These observations may have important implications for the treatment of patients with CKD.

Recent advances in the treatment of renal diseases with nebivolol: A literature review

Reactive oxygen species play an important role in both acute and chronic kidney diseases. Chronic kidney disease is associated with various consequences to the cardiovascular system and metabolic profiles. Nebivolol, a highly cardioselective third-generation β-blocker, has nitric oxide (NO) induced vasodilation and antioxidant properties. Nebivolol affects the endothelial NO pathway in two complementary ways: it increases endothelial mediated NO expression and has antioxidant action, which leads to a decrease in degradation. Central blood pressure can be effectively lowered by nebivolol in the prehypertension phase. Clinically nebivolol's ability to modulate endothelial dysfunction may offer additional vascular protection in treating hypertension. As well, pre-treatment with 5mg nebivolol every 24 hours for 4 days is protective against nephrotoxic effects of contrast media. The aim of this study is to review the current literature on the efficacy and safety of nebivolol in the treatment of various states of renal diseases.

Bedside-to-Bench Translational Research for Chronic Heart Failure: Creating an Agenda for Clients Who Do Not Meet Trial Enrollment Criteria

Congestive heart failure (CHF) is a chronic condition usually without cure. Significant developments, particularly those addressing pathophysiology, mainly started at the bench. This approach has seen many clinical observations initially explored at the bench, subsequently being trialed at the bedside, and eventually translated into clinical practice. This evidence, however, has several limitations, importantly the generalizability or external validity. We now acknowledge that clinical management of CHF is more complicated than merely translating bench-to-bedside evidence in a linear fashion. This review aims to help explore this evolving area from an Australian perspective. We describe the continuation of research once core evidence is established and describe how clinician-scientist collaboration with a bedside-to-bench view can help enhance evidence translation and generalizability. We describe why an extension of the available evidence or generating new evidence is occasionally needed to address the increasingly diverse cohort of patients. Finally, we explore some of the tools used by basic scientists and clinicians to develop evidence and describe the ones we feel may be most beneficial.

The association of the vanin-1 N131S variant with blood pressure is mediated by endoplasmic reticulum-associated degradation and loss of function

High blood pressure (BP) is the most common cardiovascular risk factor worldwide and a major contributor to heart disease and stroke. We previously discovered a BP-associated missense SNP (single nucleotide polymorphism)–rs2272996–in the gene encoding vanin-1, a glycosylphosphatidylinositol (GPI)-anchored membrane pantetheinase. In the present study, we first replicated the association of rs2272996 and BP traits with a total sample size of nearly 30,000 individuals from the Continental Origins and Genetic Epidemiology Network (COGENT) of African Americans (P = 0.01). This association was further validated using patient plasma samples; we observed that the N131S mutation is associated with significantly lower plasma vanin-1 protein levels. We observed that the N131S vanin-1 is subjected to rapid endoplasmic reticulum-associated degradation (ERAD) as the underlying mechanism for its reduction. Using HEK293 cells stably expressing vanin-1 variants, we showed that N131S vanin-1 was degraded significantly faster than wild type (WT) vanin-1. Consequently, there were only minimal quantities of variant vanin-1 present on the plasma membrane and greatly reduced pantetheinase activity. Application of MG-132, a proteasome inhibitor, resulted in accumulation of ubiquitinated variant protein. A further experiment demonstrated that atenolol and diltiazem, two current drugs for treating hypertension, reduce the vanin-1 protein level. Our study provides strong biological evidence for the association of the identified SNP with BP and suggests that vanin-1 misfolding and degradation are the underlying molecular mechanism.

Hypertension (HTN) or high blood pressure (BP) is common worldwide and a major risk factor for cardiovascular disease and all-cause mortality. Identification of genetic variants of consequence for HTN serves as the molecular basis for its treatment. Using admixture mapping analysis of the Family Blood Pressure Program data, we recently identified that the VNN1 gene (encoding the protein vanin-1), in particular SNP rs2272996 (N131S), was associated with BP in both African Americans and Mexican Americans. Vanin-1 was reported to act as an oxidative stress sensor using its pantetheinase enzyme activity. Because a linkage between oxidative stress and HTN has been hypothesized for many years, vanin-1's pantetheinase activity offers a physiologic rationale for BP regulation. Here, we first replicated the association of rs2272996 with BP in the Continental Origins and Genetic Epidemiology Network (COGENT), which included nearly 30,000 African Americans. We further demonstrated that the N131S mutation in vanin-1 leads to its rapid degradation in cells, resulting in loss of function on the plasma membrane. The loss of function of vanin-1 is associated with reduced BP. Therefore, our results indicate that vanin-1 is a new candidate to be manipulated to ameliorate HTN.