beta-blocker use and diabetes symptom score: results from the GEMINI study

Past and present of beta arrestins: A new perspective on insulin secretion and effect

BACKGROUND

Beta arrestins had been known as intracellular adaptors that uncouple and inactivate the G protein-coupled receptors that they interact with. Their roles as signal initiators for some receptors have recently been recognized.

SCOPE OF REVIEW

In this review, we focused on their role in mediating metabolic modulation primarily in relation to insulin signaling. Commenced by the upstream receptor, they seem to act like intracellular hubs that divert the metabolic profile of the cell. The amount of metabolic substrates in circulation and their usage/deposition by tissues are controlled by the contribution of all systems in the organism. This control is enabled by the release of hormones such as insulin, glucagon and glucagon-like peptide-1. Intriguingly, some ligands -either agonists or antagonists-of different classes of receptors have preferential properties mediated by β arrestins. This is not surprizing considering that substrate supply and usage should parallel physiological function such as hormone release or muscle contraction.

MAJOR CONCLUSIONS

Available data indicate that β arrestins conduct the regulatory role in insulin secretion and action. They may be good candidates to target when the upstream signal demands the function that may compromise the cell. An example is carvedilol that is protective by preventing the stimulatory effects of excessive catecholamines, stimulates mitochondrial function and has preferential clinical outcomes in metabolic disorders.

Concomitant Use of Sulfonylureas and β-Blockers and the Risk of Severe Hypoglycemia Among Patients With Type 2 Diabetes: A Population-Based Cohort Study

OBJECTIVE

The hypoglycemic potential of β-blockers among users of sulfonylureas, drugs that strongly increase the risk of this potentially fatal adverse effect, is not well understood. Our population-based cohort study assessed the potential association between concomitant use of sulfonylureas and β-blockers versus use of sulfonylureas alone and the risk of severe hypoglycemia.

RESEARCH DESIGN AND METHODS

Using the U.K. Clinical Practice Research Datalink Aurum, we included patients initiating sulfonylureas between 1998 and 2020, excluding those with β-blocker use in the past 6 months. Time-dependent Cox models estimated hazard ratios (HRs) with 95% CIs of severe hypoglycemia (hospitalization with or death resulting from hypoglycemia; ICD-10 codes E16.0, E16.1, and E16.2) associated with current concomitant use of sulfonylureas and β-blockers compared with current sulfonylurea use alone, adjusted for baseline confounders. We also compared current concomitant use of sulfonylureas and non-cardioselective versus cardioselective β-blockers.

RESULTS

Our cohort included 252,869 initiators of sulfonylureas (mean age 61.3 years; 43% female). Median follow-up was 7.9 years. The crude incidence rate of severe hypoglycemia was 7.8 per 1,000 per year. Concomitant use of sulfonylureas and β-blockers was associated with an increased risk of severe hypoglycemia compared with sulfonylurea use alone (HR 1.53; 95% CI 1.42-1.65). There was no difference in the risk between concomitant use of sulfonylureas and noncardioselective β-blockers and concomitant use of sulfonylureas and cardioselective β-blockers (HR 0.95; 95% CI 0.74-1.24).

CONCLUSIONS

β-blockers could further increase the risk of severe hypoglycemia when used concurrently with sulfonylureas. β-blocker cardioselectivity did not seem to play a major role in this regard.

Drug Interactions Affecting Antiarrhythmic Drug Use

Antiarrhythmic drugs (AAD) play an important role in the management of arrhythmias. Drug interactions involving AAD are common in clinical practice. As AADs have a narrow therapeutic window, both pharmacokinetic as well as pharmacodynamic interactions involving AAD can result in serious adverse drug reactions ranging from arrhythmia recurrence, failure of device-based therapy, and heart failure, to death. Pharmacokinetic drug interactions frequently involve the inhibition of key metabolic pathways, resulting in accumulation of a substrate drug. Additionally, over the past 2 decades, the P-gp (permeability glycoprotein) has been increasingly cited as a significant source of drug interactions. Pharmacodynamic drug interactions involving AADs commonly involve additive QT prolongation. Amiodarone, quinidine, and dofetilide are AADs with numerous and clinically significant drug interactions. Recent studies have also demonstrated increased morbidity and mortality with the use of digoxin and other AAD which interact with P-gp. QT prolongation is an important pharmacodynamic interaction involving mainly Vaughan-Williams class III AAD as many commonly used drug classes, such as macrolide antibiotics, fluoroquinolone antibiotics, antipsychotics, and antiemetics prolong the QT interval. Whenever possible, serious drug-drug interactions involving AAD should be avoided. If unavoidable, patients will require closer monitoring and the concomitant use of interacting agents should be minimized. Increasing awareness of drug interactions among clinicians will significantly improve patient safety for patients with arrhythmias.

Carvedilol prevents impairment of the counterregulatory response in recurrently hypoglycaemic diabetic rats

Aim

It has been suggested that repeated activation of the adrenergic system during antecedent episodes of hypoglycaemia contributes to the development of counterregulatory failure. We previously reported that treatment with carvedilol, a non-specific β-blocker, prevented the development of counterregulatory failure and improved hypoglycaemia awareness in recurrently hypoglycaemic non-diabetic rats. The current study investigated whether carvedilol has similar benefits in diabetic rats.

Methods

Recurrently hypoglycaemic streptozotocin-diabetic rats (STZ+RH) were treated with carvedilol for one week prior to undergoing a hypoglycaemic clamp. Hypoglycaemia awareness was evaluated in streptozotocin-diabetic rats made hypoglycaemia unaware using repeated injections of 2-deoxyglucose.

Results

Compared to hypoglycaemia-naïve STZ-diabetic controls, exogenous glucose requirements were more than doubled in the STZ+RH animals and this was associated with a 49% reduction in the epinephrine response to hypoglycaemia. Treating STZ+RH animals with carvedilol improved the epinephrine response to hypoglycaemia. Of note, neither recurrent hypoglycaemia nor carvedilol treatment affected the glucagon response in diabetic animals. Additionally, carvedilol treatment improved the feeding response to insulin-induced hypoglycaemia in diabetic animals made 'hypoglycaemia unaware' using repeated injections of 2-deoxyglucose, suggesting the treatment improved awareness of hypoglycaemia as well.

Conclusion

Our data suggest that carvedilol may be useful in preventing impairments of the sympathoadrenal response and the development of hypoglycaemia unawareness during recurring episodes of hypoglycaemia in diabetic animals.

Diabetogenic effects of cardioprotective drugs

Drugs that protect against cardiovascular events in the patient with diabetes may also positively or negatively affect glycaemic control in the patient with established diabetes and may induce the development of diabetes in the predisposed patient. Mainly through increasing insulin resistance, beta-blockers, statins and high-dose diuretics have the potential to worsen glycaemic control. Dihydropyridine calcium channel blockers, low-dose diuretics, vasodilating beta-blockers, alpha-blockers and pitavastatin have little or no effect on glycaemic control. Blockers of the renin-angiotensin-aldosterone system, colesevelam, ranolazine and verapamil, through slowing breakdown of bradykinin, vasodilation, increasing cholecystokinin levels, blocking sodium channels and decreasing beta cell apoptosis, may improve glycaemic control and avoid the development of diabetes.

Beta-blocker-associated hypoglycaemia: New insights from a real-world pharmacovigilance study

AIMS

To investigate the statistical association between hypoglycaemia and β-blocker use and to define what patient and drug characteristics could potentially increase the risk for its occurrence.

METHODS

We investigated the relationship between pharmacological parameters of β-blockers and the occurrence of hypoglycaemia by conducting a case/non case analysis using the Food and Drug Administration Adverse Event Reporting System database. Pharmacological properties that could represent a predictive factor for hypoglycaemia were analysed through a multilinear binary logistic regression (null hypothesis rejected for values of P < .05). We also performed a systematic review of clinical studies on this association.

RESULTS

Of 83 954 selected reports, 1465 cases (1.75%) of hypoglycaemia were identified. The association was found statistically significant for nadolol (reporting odds ratio [95% confidence interval]: 6.98 [5.40-9.03]), celiprolol (2.35 [1.35-4.10]), propranolol (2.14 [1.87-2.46]) and bisoprolol (1.42 [1.25-1.61]). Paediatric cases (n = 310) showed a positive association with hypoglycaemia for long half-life drugs (odds ratio [95% confidence interval]: 2.232 [1.398-3.563]) and a negative association for β1-selectivity (0.644 [0.414-0.999]). Seven papers were included in the systematic review. Because of great heterogeneity in study design and demographics, hypoglycaemia incidence rates varied greatly among studies, occurring in 1.73% of the cases for propranolol treatment (n total participants = 575), 6.6% for atenolol (n = 30) and 10% for carvedilol (n = 20).

CONCLUSION

Nadolol appears to be the β-blocker significantly most associated with hypoglycaemia and children represent the most susceptible sample. Furthermore, long half-life and nonselective β-blockers seem to increase the risk for its occurrence.

Carvedilol and metoprolol are both able to preserve myocardial function in type 2 diabetes

PURPOSE

Increasing cohorts of patients present with diabetic cardiomyopathy, and with no targeted options, treatment often rely on generic pharmaceuticals such as β-blockers. β-blocker efficacy is heterogenous, with second generation β-blocker metoprolol selectively inhibiting β₁ -AR, while third generation β-blocker carvedilol has α₁ -AR inhibition, antioxidant, and anti-apoptotic actions alongside nonselective β-AR inhibition. These additional properties have led to the hypothesis that carvedilol may improve cardiac contractility in the diabetic heart to a greater extent than metoprolol. The present study aimed to compare the efficacy of metoprolol and carvedilol on myocardial function in animal models and cardiac tissue from patients with type 2 diabetes and preserved ejection fraction.

METHODS

Echocardiographic examination of cardiac function and assessment of myocardial function in isolated trabeculae was carried out in patients with and without diabetes undergoing coronary artery bypass grafting (CABG) who were prescribed metoprolol or carvedilol. Equivalent measures were undertaken in Zucker Diabetic Fatty (ZDF) rats following 4 weeks treatment with metoprolol or carvedilol.

RESULTS

Patients receiving carvedilol compared to metoprolol had no difference in cardiac function, and no difference was apparent in myocardial function between β-blockers. Both β-blockers similarly improved myocardial function in diabetic ZDF rats treated for 4 weeks, without significantly affecting in vivo cardiac function.

CONCLUSIONS

Metoprolol and carvedilol were found to have no effect on cardiac function in type 2 diabetes with preserved ejection fraction, and were similarly effective in preventing myocardial dysfunction in ZDF rats.

Effect of beta blocker use and type on hypoglycemia risk among hospitalized insulin requiring patients

Background

Although beta blockers could increase the risk of hypoglycemia, the difference between subtypes on hypoglycemia and mortality have not been studied. This study sought to determine the relationship between type of beta blocker and incidence of hypoglycemia and mortality in hospitalized patients.

Methods

We retrospectively identified non-critically ill hospitalized insulin requiring patients who were undergoing bedside glucose monitoring and received either carvedilol or a selective beta blocker (metoprolol or atenolol). Patients receiving other beta blockers were excluded. Hypoglycemia was defined as any glucose < 3.9 mmol/L within 24 h of admission (Hypo_1day) or throughout hospitalization (Hypo_T) and any glucose < 2.2 mmol/L throughout hospitalization (Hypo_severe).

Results

There were 1020 patients on carvedilol, 886 on selective beta blockers, and 10,216 on no beta blocker at admission. After controlling for other variables, the odds of Hypo_1day, Hypo_T and Hypo_severe were higher for carvedilol and selective beta blocker recipients than non-recipients, but only in basal insulin nonusers. The odds of Hypo_1day (odds ratio [OR] 1.99, 95% confidence interval [CI] 1.28, 3.09, p = 0.0002) and Hypo_T (OR 1.38, 95% CI 1.02, 1.86, p = 0.03) but not Hypo_severe (OR 1.90, 95% CI 0.90, 4.02, p = 0.09) were greater for selective beta blocker vs. carvedilol recipients in basal insulin nonusers. Hypo_1day, Hypo_T, and Hypo_severe were all associated with increased mortality in adjusted models among non-beta blocker and selective beta blocker recipients, but not among carvedilol recipients.

Conclusions

Beta blocker use is associated with increased odds of hypoglycemia among hospitalized patients not requiring basal insulin, and odds are greater for selective beta blockers than for carvedilol. The odds of hypoglycemia-associated mortality are increased with selective beta blocker use or nonusers but not in carvedilol users, warranting further study.

Insulin Release Mechanism Modulated by Toxins Isolated from Animal Venoms: From Basic Research to Drug Development Prospects

Venom from mammals, amphibians, snakes, arachnids, sea anemones and insects provides diverse sources of peptides with different potential medical applications. Several of these peptides have already been converted into drugs and some are still in the clinical phase. Diabetes type 2 is one of the diseases with the highest mortality rate worldwide, requiring specific attention. Diverse drugs are available (e.g., Sulfonylureas) for effective treatment, but with several adverse secondary effects, most of them related to the low specificity of these compounds to the target. In this context, the search for specific and high-affinity compounds for the management of this metabolic disease is growing. Toxins isolated from animal venom have high specificity and affinity for different molecular targets, of which the most important are ion channels. This review will present an overview about the electrical activity of the ion channels present in pancreatic β cells that are involved in the insulin secretion process, in addition to the diversity of peptides that can interact and modulate the electrical activity of pancreatic β cells. The importance of prospecting bioactive peptides for therapeutic use is also reinforced.

Carvedilol prevents counterregulatory failure and impaired hypoglycaemia awareness in non-diabetic recurrently hypoglycaemic rats

AIMS/HYPOTHESIS

This study evaluates whether the non-selective β-blocker, carvedilol, can be used to prevent counterregulatory failure and the development of impaired awareness of hypoglycaemia (IAH) in recurrently hypoglycaemic rats.

METHODS

Sprague Dawley rats were implanted with vascular catheters and intracranial guide cannulas targeting the ventromedial hypothalamus (VMH). These animals underwent either three bouts of insulin-induced hypoglycaemia or received three saline injections (control group) over 3 days. A subgroup of recurrently hypoglycaemic animals was treated with carvedilol. The next day, the animals underwent a hypoglycaemic clamp with microdialysis without carvedilol treatment to evaluate changes in central lactate and hormone levels. To assess whether carvedilol prevented IAH, we treated rats that had received repeated 2-deoxyglucose (2DG) injections to impair their awareness of hypoglycaemia with carvedilol and measured food intake in response to insulin-induced hypoglycaemia as a surrogate marker for hypoglycaemia awareness.

RESULTS

Compared with the control group, recurrently hypoglycaemic rats had a ~1.7-fold increase in VMH lactate and this was associated with a 75% reduction in the sympathoadrenal response to hypoglycaemia. Treatment with carvedilol restored VMH lactate levels and improved the adrenaline (epinephrine) responses. In 2DG-treated rats compared with control animals receiving saline, food intake was reduced in response to hypoglycaemia and increased with carvedilol treatment.

CONCLUSIONS/INTERPRETATION

We conclude that carvedilol may be a useful therapy to prevent counterregulatory failure and improve IAH.

Interdisciplinary approach to compensation of hypoglycemia in diabetic patients with chronic heart failure

Diabetes mellitus is a chronic disease requiring lifelong control with hypoglycemic agents that must demonstrate excellent efficacy and safety profiles. In patients taking glucose-lowering drugs, hypoglycemia is a common cause of death associated with arrhythmias, increased thrombus formation, and specific effects of catecholamines due to sympathoadrenal activation. Focus is now shifting from merely glycemic control to multifactorial approach. In the context of individual drugs and classes, this article reviews interdisciplinary strategies evaluating metabolic effects of drugs for treatment of chronic heart failure (CHF) which can mask characteristic hypoglycemia symptoms. Hypoglycemia unawareness and cardiac autonomic neuropathy are discussed. Data suggesting that hypoglycemia modulates immune response are reviewed. The potential role of gut microbiota in improving health of patients with diabetes and CHF is emphasized. Reports stating that nondiabetic CHF patients can have life-threatening hypoglycemia associated with imbalance of thyroid hormones are discussed. Regular glycemic control based on HbA1c measurements and adequate pharmacotherapy remain the priorities in diabetes management. New antihyperglycemic drugs with safer profiles should be preferred in vulnerable CHF patients. Multidrug interactions must be considered. Emerging therapies with reduced hypoglycemia risk, telemedicine, sensor technologies, and genetic testing predicting hypoglycemia risk may help solving the challenges of hypoglycemia in CHF patients with diabetes. Interdisciplinary work may involve cardiologists, diabetologists/endocrinologists, immunologists, gastroenterologists, microbiologists, nutritionists, imaging specialists, geneticists, telemedicine experts, and other relevant specialists. This review emphasizes that systematic knowledge on pathophysiology of hypoglycemia in diabetic patients with CHF is largely lacking and the gaps in our understanding require further discoveries.

Carvedilol: a third-generation β-blocker should be a first-choice β-blocker

β-Blockers are a standard of care in many clinical settings such as acute myocardial infarction, heart failure and patients at risk for a coronary event. However, not all β-blockers are the same and they vary in properties such as lipophilicity, metabolic profile, receptor inhibition, hemodynamics, tolerability and antioxidant/anti-inflammatory effects. It has been unclear whether these differences affect outcomes or if one β-blocker should be preferred over another. This review will summarize the properties of metoprolol, atenolol and carvedilol, as well as comparative experimental and clinical trials between these agents. We will provide compelling evidence of why carvedilol should be a first-line β-blocker and why it offers many advantages over the β1-selective β-blockers.

Health-related quality of life in hypertension, chronic kidney disease, and coexistent chronic health conditions

With the increasing prevalence of hypertension, there has been a growing interest in understanding the health-related quality of life (HRQOL) of patients with hypertension. Although hypertension is often perceived as asymptomatic, it is associated with impaired HRQOL because of complications or comorbidities, awareness of the diagnosis, and adverse effects from antihypertensive medications. This article focuses on the literature published since 2000, on HRQOL in elderly hypertensive individuals as well as hypertensives with co-existent diseases, including chronic kidney disease, cardiovascular disease, and diabetes mellitus. Most of the studies found that hypertensive individuals with co-existent co-morbidities tend to have lower HRQOL than those with hypertension alone, and identified the number of co-morbid illnesses as an independent determinant of HRQOL. The most pronounced effect was noted in the physical function domains of HRQOL. Studies have also examined the effects on HRQOL of specific classes of antihypertensive drugs without specific demonstration of superiority of one drug class over another in terms of HRQOL measures. Although there is evidence in favor of angiotensin-converting enzyme-inhibition for improving renal and cardiovascular outcomes in hypertensive patients, its role in ameliorating HRQOL outcomes remains to be established.

Optimal use of beta-blockers in high-risk hypertension: a guide to dosing equivalence

Hypertension is the number one diagnosis made by primary care physicians, placing them in a unique position to prescribe the antihypertensive agent best suited to the individual patient. In individuals with diabetes mellitus, blood pressure (BP) levels >130/80 mmHg confer an even higher risk for cardiovascular and renal disease, and these patients will benefit from aggressive antihypertensive treatment using a combination of agents. β-blockers are playing an increasingly important role in the management of hypertension in high-risk patients. β-blockers are a heterogeneous class of agents, and this review presents the differences between β-blockers and provides evidence-based protocols to assist in understanding dose equivalence in the selection of an optimal regimen in patients with complex needs. The clinical benefits provided by β-blockers are only effective if patients adhere to medication treatment long term. β-blockers with proven efficacy, once-daily dosing, and lower side effect profiles may become instrumental in the treatment of hypertensive diabetic and nondiabetic patients.

Treatment of diabetic hypertension

Insulin resistance and hyperglycaemia combine to make hypertension more prevalent in the type 2 diabetic patient. Blood pressure goals below those for the non-diabetic subject have been shown to be more effective in lowering mortality and cardiovascular events in the diabetic patient. To achieve these goals in most cases, three to five antihypertensives from different therapeutic groups need to be utilized. Suppression of the renin-angiotensin system (RAS) with angiotensin-converting enzyme inhibitors, angiotensin 2 receptor blockers or a renin inhibitor should be the primary therapy. A second goal should be suppression of the sympathetic nervous system utilizing a beta-blocker that does not increase insulin resistance. The addition of a diuretic, calcium channel blocker or a vasodilator to suppressors of the RAS and sympathetic nervous system aid in achieving hypertensive goals in the diabetic patient. Achieving hypertensive goals with suppression of the RAS and sympathetic nervous system should result in a decrease in mortality and cardiovascular events in the diabetic hypertensive patient. In this review article, the benefits and disadvantages of the different antihypertensive therapies in the diabetic patient are discussed.

Controlled-release carvedilol in the management of systemic hypertension and myocardial dysfunction

Cardiovascular disease is the leading cause of death worldwide. Within the treatment armamentarium, beta-blockers have demonstrated efficacy across the spectrum of cardiovascular disease--from modification of a risk factor (ie, hypertension) to treatment after an acute event (ie, myocardial infarction). Recently, the use of beta-blockers as a first-line therapy in hypertension has been called into question. Moreover, beta-blockers as a class are saddled with a misperception of having poor tolerability. However, vasodilatory beta-blockers such as carvedilol have a different hemodynamic action that provides the benefits of beta-blockade with the addition of vasodilation resulting from alpha 1-adrenergic receptor blockade. Vasodilation reduces total peripheral resistance, which may produce an overall positive effect on tolerability. Recently, a new, controlled-release carvedilol formulation has been developed that provides the clinical efficacy of carvedilol but is indicated for once-daily dosing. This review presents an overview of the clinical and pharmacologic carvedilol controlled-release data.