Cardiovascular drug class specificity: β-blockers

Compromised trigemino-coerulean coupling in migraine sensitization can be prevented by blocking beta-receptors in the locus coeruleus

BACKGROUND

Migraine is a disabling neurological disorder, characterized by recurrent headaches. During migraine attacks, individuals often experience sensory symptoms such as cutaneous allodynia which indicates the presence of central sensitization. This sensitization is prevented by oral administration of propranolol, a common first-line medication for migraine prophylaxis, that also normalized the activation of the locus coeruleus (LC), considered as the main origin of descending noradrenergic pain controls. We hypothesized that the basal modulation of trigeminal sensory processing by the locus coeruleus is shifted towards more facilitation in migraineurs and that prophylactic action of propranolol may be attributed to a direct action in LC through beta-adrenergic receptors.

METHODS

We used simultaneous in vivo extracellular recordings from the trigeminocervical complex (TCC) and LC of male Sprague-Dawley rats to characterize the relationship between these two areas following repeated meningeal inflammatory soup infusions. Von Frey Hairs and air-puff were used to test periorbital mechanical allodynia. RNAscope and patch-clamp recordings allowed us to examine the action mechanism of propranolol.

RESULTS

We found a strong synchronization between TCC and LC spontaneous activities, with a precession of the LC, suggesting the LC drives TCC excitability. Following repeated dural-evoked trigeminal activations, we observed a disruption in coupling of activity within LC and TCC. This suggested an involvement of the two regions' interactions in the development of sensitization. Furthermore, we showed the co-expression of alpha-2A and beta-2 adrenergic receptors within LC neurons. Finally propranolol microinjections into the LC prevented trigeminal sensitization by desynchronizing and decreasing LC neuronal activity.

CONCLUSIONS

Altogether these results suggest that trigemino-coerulean coupling plays a pivotal role in migraine progression, and that propranolol's prophylactic effects involve, to some extent, the modulation of LC activity through beta-2 adrenergic receptors. This insight reveals new mechanistic aspects of LC control over sensory processing.

Beta-Blockers and Their Current Role in Maternal and Neonatal Health: A Narrative Review of the Literature

Beta-blockers are a class of medications that act on beta-adrenergic receptors and are categorized as cardio-selective and non-selective. They are principally used to treat cardiovascular conditions such as hypertension and arrhythmias. Beta-blockers have also been used to treat non-cardiogenic indications in non-pregnant individuals and the pediatric population. In pregnancy, labetalol is the mainstay treatment for hypertension and other cardiovascular indications. However, contraindications to certain sub-types of beta-blockers include bradycardia, heart failure, obstructive lung diseases, and hemodynamic instability. There is conflicting evidence of the adverse effects on fetal and neonatal health due to a scarce safety and efficacy profile, and further studies are necessary to understand the pharmacokinetics of the different classes of beta-blockers in pregnancy and fetal health. Understanding the hemodynamic changes during the stages of pregnancy is important to target a more beneficial therapy for both mother and fetus as well as better neonatal outcomes. Beta-blocker use in the pediatric population is less documented in studies but does have the potential to treat various cardiogenic and non-cardiogenic conditions. Future comprehensive studies would further benefit the direction of beta-blocker treatment during pregnancy in neonates and pediatrics.

The small molecule ACM-001 improves cardiac function in a rat model of severe cancer cachexia

AIMS

Cachexia, a common manifestation of malignant cancer, is not only associated with weight loss, but also with severe cardiac atrophy and impaired cardiac function. Here, we investigated the effects of ACM-001 (0.3 or 3 mg/kg/day) in comparison to carvedilol (3 or 30 mg/kg/day), metropolol (50 or 100 mg/kg/day), nebivolol (1 or 10 mg/kg/day) and tertatolol (0.5 or 5 mg/kg/day) on cardiac mass and function in a rat cancer cachexia model.

METHODS AND RESULTS

Young male Wistar Han rats were inoculated i.p. with 108 Yoshida hepatoma AH-130 cells and treated once daily with verum or placebo by gavage. Cardiac function (echocardiography), body weight and body composition (nuclear magnetic resonance scans) were assessed. The hearts of animals were euthanized on day 11 (placebo and 3 mg/kg/day ACM-001) were used for signalling studies. Beta-blockers had no effect on tumour burden. ACM-001 reduced body weight loss (placebo: -34 ± 2.4 g vs. 3 mg/kg/day ACM-001: -14.8 ± 8.4 g, p = 0.033). Lean mass wasting was attenuated (placebo: -16.5 ± 2.34 g vs. 3 mg/kg/day ACM-001: -2.4 ± 6.7 g, p = 0.037), while fat loss was similar (p = 0.4) on day 11. Placebo animals lost left ventricular mass (-101 ± 14 mg), which was prevented only by 3 mg/kg/day ACM-001 (7 ± 25 mg, p < 0.01 vs. placebo). ACM-001 improved the ejection fraction (EF) (ΔEF: placebo: -24.3 ± 2.6 vs. 3 mg/kg/day ACM-001: 0.1 ± 2.9, p < 0.001). Cardiac output was 50% lower in the placebo group (-41 ± 4 ml/min) compared to baseline, while 3 mg/kg/day ACM-001 preserved cardiac output (-5 ± 8 ml/min, p < 0.01). The molecular mechanisms involved inhibition of protein degradation and activation of protein synthesis pathways.

CONCLUSION

This study shows that 3 mg/kg/day ACM-001 restores the anabolic/catabolic balance in cardiac muscle leading to improved function. Moreover, not all beta-blockers have similar effects.

Blockade of ß-Adrenergic Receptors by Nebivolol Enables Tumor Control Potential for Uveal Melanoma in 3D Tumor Spheroids and 2D Cultures

Uveal melanoma (UM) is the most common primary cancer of the eye in adults. A new systemic therapy is needed to reduce the high metastasis and mortality rate. As β-blockers are known to have anti-tumor effects on various cancer entities, this study focuses on investigating the effect of β1-selective blockers atenolol, celiprolol, bisoprolol, metoprolol, esmolol, betaxolol, and in particular, nebivolol on UM. The study was performed on 3D tumor spheroids as well as 2D cell cultures, testing tumor viability, morphological changes, long-term survival, and apoptosis. Flow cytometry revealed the presence of all three β-adrenoceptors with a dominance of β2-receptors on cell surfaces. Among the blockers tested, solely nebivolol concentration-dependently decreased viability and altered 3D tumor spheroid structure. Nebivolol blocked the repopulation of cells spreading from 3D tumor spheroids, indicating a tumor control potential at a concentration of ≥20 µM. Mechanistically, nebivolol induced ATP depletion and caspase-3/7 activity, indicating that mitochondria-dependent signaling is involved. D-nebivolol or nebivolol combined with the β2-antagonist ICI 118.551 displayed the highest anti-tumor effects, suggesting a contribution of both β1- and β2-receptors. Thus, the present study reveals the tumor control potential of nebivolol in UM, which may offer a perspective for co-adjuvant therapy to reduce recurrence or metastasis.

β-adrenoceptor antagonists and nightmares: A pharmacoepidemiological-pharmacodynamic study

AIM

To compare different β-adrenoceptor antagonists for the risk of reporting nightmare.

METHODS

The study involved two approaches: first, we investigated in VigiBase^®, the World Health Organization Individual Case Safety Report (ICSR) database, the disproportionality between exposure to each β-adrenoceptor antagonists and reports of nightmares between 1967 and 2019. Second, in a pharmacoepidemiological-pharmacodynamic analysis, we assessed whether use of β-adrenoceptor antagonists with moderate and high lipid solubility or strong 5-HT_1A affinity were associated with an increased risk of reporting nightmares. We conducted multivariate logistic regression to estimate reporting odds ratios (RORs) of nightmares compared to all other adverse drug reactions.

RESULTS

Of the 126,964 reports recorded with β-adrenoceptor antagonists, 1138 (0.9%) were nightmares. The highest risk of reporting a nightmare was found with exposure of pindolol (adjusted ROR 2.82, 95%CI, 2.19-3.61), metoprolol (1.89, 1.66-2.16), and alprenolol (1.77, 1.06-2.97). Compared to use of low lipid solubility β-adrenoceptor antagonists, use of moderate or high lipid solubility β-adrenoceptor antagonists were significantly more associated with nightmare reports (aROR moderate vs. low 1.72, 95%CI 1.47-2.00 and aROR high vs. low 1.84, 95%CI 1.53-2.22). Use of moderate or high 5-HT_1A affinity of β-adrenoceptor antagonists was associated with an increased ROR of nightmares compared with low 5-HT_1A affinity of β-adrenoceptor antagonists (aROR moderate vs. low 1.22, 95%CI 1.04-1.43 and aROR high vs. low 2.46, 95%CI 1.93-3.13).

CONCLUSION

In our large pharmacovigilance study, nightmares are more frequently reported for pindolol and metoprolol, and among β-adrenoceptor antagonists with high lipid solubility and high 5-HT_1A receptor affinity.

Ivabradine versus bisoprolol in the treatment of inappropriate sinus tachycardia: a long-term follow-up study

AIM

The aim of our study was to compare ivabradine versus bisoprolol in the short-term and long-term treatment of inappropriate sinus tachycardia.

METHODS

From this prospective, parallel-group, open-label study, consecutive patients affected by inappropriate sinus tachycardia received ivabradine or bisoprolol and were evaluated with Holter ECG, ECG stress test, European Heart Rhythm Association score and Minnesota Living With Heart Failure Questionnaire at baseline, after 3 and 24 months.

RESULTS

Overall, 40 patients were enrolled. Baseline parameters were comparable in the ivabradine and bisoprolol subgroups. Two patients had transient phosphenes with ivabradine and two others interrupted the drug after 3 months as they planned to become pregnant. Eight individuals treated with bisoprolol experienced hypotension and weakness, which caused drug discontinuation in five of them. Ivabradine was superior to bisoprolol in reducing Holter ECG mean heart rate (HR) and mean HR during daytime at short- and long-term follow-up. Moreover, ivabradine but not bisoprolol significantly reduced Holter ECG mean HR during night-time as well as maximal and minimal HR and significantly increased the time duration and maximal load reached at ECG stress test. The quality of life questionnaires significantly improved in both subgroups.

CONCLUSION

This study suggests that ivabradine is better tolerated than bisoprolol and seems to be superior in controlling the heart rate and improving exercise capacity in a small population of individuals affected by inappropriate sinus tachycardia during a short-term and long-term follow-up.

Mucoadhesive Gelatin Buccal Films with Propranolol Hydrochloride: Evaluation of Mechanical, Mucoadhesive, and Biopharmaceutical Properties

This study processes and characterizes propranolol hydrochloride/gelatin mucoadhesive buccal films. Two types of gelatin are used: Gelatin from porcine skin, type A (GA), and gelatin from bovine skin (GB). The influence of gelatin type on mechanical, mucoadhesive, and biopharmaceutical characteristics of buccal films is evaluated. Fourier-Transfer infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) analysis show that GA with propranolol hydrochloride (PRH) in the film (GAP) formed a physical mixture, whereas GB with PRH (GBP) form a compound-complex. Results of mechanical testing (tensile test, hardness) revealed that GAP films exhibit higher elastic modulus, tensile strength, and hardness. A mucoahesion test shows that GBP has higher adhesion strength, while GAP shows higher work of adhesion. Both in vitro release study and in silico simulation indicated that processed films can provide effective drug transport through the buccal mucosa. In silico simulation shows improved bioavailability from buccal films, in comparison to the immediate-release tablets-indicating that the therapeutic drug dose can be markedly reduced.

Neuropsychiatric Consequences of Lipophilic Beta-Blockers

Beta-blockers are a class of drugs with important benefits in cardiovascular pathology. In this paper, we aim to highlight their adverse and therapeutic effects in the neuropsychiatric field. With respect to permeability, we would like to mention that most beta-blockers are lipophilic and can cross the blood–brain barrier. Observational studies show the presence of neuropsychiatric side effects when taking beta-blockers, and is the reason for which caution is recommended in their use in patients with depressive syndrome. From a therapeutic point of view, most current evidence is for the use of beta-blockers in migraine attacks, essential tremor, and akathisia. Beta-blockers appear to be effective in the treatment of aggressive behavior, beneficial in the prevention of posttraumatic stress syndrome and may play a role in the adjuvant treatment of obsessive–compulsive disorder, which is refractory to standard therapy. In conclusion, the relationship between beta-blockers and the central nervous system appears as a two-sided coin. Summarizing the neuropsychiatric side effects of beta-blockers, we suggest that clinicians pay special attention to the pharmacological properties of different beta-blockers.

Speeding up beta-blockade prior to coronary CT angiography: can we predict the dose of intravenous metoprolol required to achieve target heart rate in a given patient?

AIM

To evaluate the use and safety of intravenous (IV) metoprolol in a cohort of patients undergoing coronary computed tomographic angiography (CCTA) at a university hospital, and in particular, to establish if the minimum dose required to achieve the target heart rate (HR) in a given patient can be predicted from the baseline HR.

MATERIALS AND METHODS

Patients undergoing CCTA at a tertiary centre between January 2015 and May 2018, with baseline HR ≥60 bpm requiring IV metoprolol, were identified retrospectively from the database. Patients with a contraindication to beta-blockade or an indication for CCTA other than coronary disease were excluded. HR at baseline and at the time of scanning were recorded, together with the total dose of IV metoprolol administered.

RESULTS

Of 625 patients identified, 330 (52.8%) achieved HR ≤60 with IV metoprolol. Patients who achieved target HR had lower baseline HR. They received a lower radiation exposure due to tight prospective gating and a lower tube voltage. The lower quartile dose of metoprolol administered was 5 mg for patients with baseline HR <65 beats per minute (bpm), but 10 mg for HR 65-74 bpm, and ≥20 mg for higher HRs. There were no cases of symptomatic bradycardia/hypotension.

CONCLUSION

Patients with a resting HR of ≥60 bpm can reasonably be given an initial minimum dose of 5-20 mg metoprolol IV before CCTA, with additional doses as required.

Use of beta-blocker types and risk of incident prostate cancer in a multiethnic population

PURPOSE

Increased adrenergic innervation is observed in prostate cancer (CaP) and is associated with aggressive disease. Emerging evidence suggests that beta-adrenergic blockade inhibits CaP progression. However, the association between type of beta-blocker use and risk of incident CaP on initial prostate biopsy has not been investigated in multiethnic populations.

MATERIALS AND METHODS

A retrospective study of racially/ethnically diverse men (64% African-American and Hispanic), who underwent initial prostate biopsy between 2006 and 2016 in a large healthcare system was performed. Oral use of beta-blocker type was assessed by reviewing active prescriptions within the 5-year period preceding initial biopsy. Patient demographics and clinical factors were collected.

RESULTS

Of 4,607 men who underwent initial prostate biopsy, 4,516 met criteria and 2,128 had a biopsy positive for CaP; 20% high-risk, 41% intermediate-risk, and 39% low or very-low risk (National Comprehensive Cancer Network classification). Overall, 15% of patients were taking a beta-blocker prior to initial biopsy, with Metoprolol, Atenolol, and Carvedilol accounting for the majority. Of beta-blocker types, Atenolol alone was associated with a 38% reduction in odds of incident CaP (P= 0.01), with a 40% and 54% reduction in risks of National Comprehensive Cancer Network intermediate and high-risk CaP (P = 0.03 and P = 0.03, respectively) compared to men not taking a beta-blocker. Furthermore, longer duration of Atenolol use (3-5 years) was associated with a 54% and 72% reduction in intermediate and high-risk disease, (P = 0.03 and P = 0.03, respectively).

CONCLUSIONS

Among beta blocker types, long-term Atenolol use is associated with a significant reduction in incident CaP risk on initial prostate biopsy for clinically-significant intermediate and high-risk disease compared to men not taking a beta-blocker.

Association of beta-blockers and first-registered heart rhythm in out-of-hospital cardiac arrest: real-world data from population-based cohorts across two European countries

Aims

Conflicting results have been reported regarding the effect of beta-blockers on first-registered heart rhythm in out-of-hospital cardiac arrest (OHCA). We aimed to establish whether the use of beta-blockers influences first-registered rhythm in OHCA.

Methods and results

We included patients with OHCA of presumed cardiac cause from two large independent OHCA-registries from Denmark and the Netherlands. Beta-blocker use was defined as exposure to either non-selective beta-blockers, β1-selective beta-blockers, or α-β-dual-receptor blockers within 90 days prior to OHCA. We calculated odds ratios (ORs) for the association of beta-blockers with first-registered heart rhythm using multivariable logistic regression. We identified 23 834 OHCA-patients in Denmark and 1584 in the Netherlands: 7022 (29.5%) and 519 (32.8%) were treated with beta-blockers, respectively. Use of non-selective beta-blockers, but not β1-selective blockers, was more often associated with non-shockable rhythm than no use of beta-blockers [Denmark: OR 1.93, 95% confidence interval (CI) 1.48–2.52; the Netherlands: OR 2.52, 95% CI 1.15–5.49]. Non-selective beta-blocker use was associated with higher proportion of pulseless electrical activity (PEA) than of shockable rhythm (OR 2.38, 95% CI 1.01–5.65); the association with asystole was of similar magnitude, although not statistically significant compared with shockable rhythm (OR 2.34, 95% CI 0.89–6.18; data on PEA and asystole were only available in the Netherlands). Use of α-β-dual-receptor blockers was significantly associated with non-shockable rhythm in Denmark (OR 1.21; 95% CI 1.03–1.42) and not significantly in the Netherlands (OR 1.37; 95% CI 0.61–3.07).

Conclusion

Non-selective beta-blockers, but not β1-selective beta-blockers, are associated with non-shockable rhythm in OHCA.

Chronic Stress Exposure Suppresses Mammary Tumor Growth and Reduces Circulating Exosome TGF-β Content via β-Adrenergic Receptor Signaling in MMTV-PyMT Mice

Preclinical models of breast cancer have established mechanistic links between psychological stress and cancer progression. However, epidemiological evidence linking stress and cancer is equivocal. We tested the impact of stress exposure in female mice expressing the mouse mammary tumor virus polyoma middle-T antigen (MMTV-PyMT), a spontaneous model of mammary adenocarcinoma that mimics metastatic hormone receptor-positive human breast cancer development. MMTV-PyMT mice were socially isolated at 6 to 7 weeks of age during premalignant hyperplasia. To increase the potency of the stressor, singly housed mice were exposed to acute restraint stress (2 hours per day for 3 consecutive days) at 8 to 9 weeks of age during early carcinoma. Exposure to this dual stressor activated both major stress pathways, the sympathetic nervous system and hypothalamic-pituitary-adrenal axis throughout malignant transformation. Stressor exposure reduced mammary tumor burden in association with increased tumor cleaved caspase-3 expression, indicative of increased cell apoptosis. Stress exposure transiently increased tumor vascular endothelial growth factor and reduced tumor interleukin-6, but no other significant alterations in immune/inflammation-associated chemokines and cytokines or changes in myeloid cell populations were detected in tumors. No stress-induced change in second-harmonic generation-emitting collagen, indicative of a switch to a metastasis-promoting tumor extracellular matrix, was detected. Systemic indicators of slowed tumor progression included reduced myeloid-derived suppressor cell (MDSC) frequency in lung and spleen, and decreased transforming growth factor β (TGF-β) content in circulating exosomes, nanometer-sized particles associated with tumor progression. Chronic β-adrenergic receptor (β-AR) blockade with nadolol abrogated stress-induced alterations in tumor burden and cleaved caspase-3 expression, lung MDSC frequency, and exosomal TGF-β content. Despite the evidence for reduced tumor growth, metastatic lesions in the lung were not altered by stress exposure. Unexpectedly, β-blockade in nonstressed mice increased lung metastatic lesions and splenic MDSC frequency, suggesting that in MMTV-PyMT mice, β-AR activation also inhibits tumor progression in the absence of stress exposure. Together, these results suggest stress exposure can act through β-AR signaling to slow primary tumor growth in MMTV-PyMT mice.

Propensity Score Matching: The 'Devil is in the Details' Where More May Be Hidden than You Know

Propensity score matching has been used with increasing frequency in the analyses of non-prespecified subgroups of randomized clinical trials, and in retrospective analyses of clinical trial data sets, registries, observational studies, electronic medical record analyses, and more. The method attempts to adjust post hoc for recognized unbalanced factors at baseline such that the data once analyzed will hopefully approximate or indicate what a prospective randomized data set-the "gold standard" for comparing two or more therapies-would have shown. However, for practical limitations, propensity score matching cannot assess and balance all the factors that come into play in the clinical management of patients and that may be present in the circumstances of the study. Thus, propensity score matching analyses may omit, due to nonrecognition, the effects of several clinically important but not considered factors that can affect the outcomes of the analyses being reported, causing them to possibly be misleading, or hypothesis-generating at best. This review discusses this issue, using several specific examples, and is targeted at clinicians to make them aware of the limitations of such analyses when they apply their results to patients in their care.

Three Generations of β-blockers: History, Class Differences and Clinical Applicability

BACKGROUND

Beta-adrenergic receptors are expressed in cardiomyocytes and activated by either noradrenaline released from sympathetic synapses or circulating catecholamines. Their corresponding receptors have three subtypes, namely, β1, β2 and β3, which are members of the G protein-coupled receptors (GPCRs) family. Activation of β1-adrenergic receptors causes various physiological reactions including cardiac contraction and renin secretion from juxtaglomerular cells of the kidney. Antagonists of β-adrenergic receptors, known as β-blockers, have been used effectively for over four decades and have beneficial effects in the treatment of cardiovascular diseases. There are three generations of β-blockers according to their pharmacological properties. Firstgeneration β-blockers are non-selective, blocking both β1- and β2-receptors; second-generation β- blockers are more cardioselective in that they are more selective for β1-receptors; and thirdgeneration β-blockers are highly selective drugs for β1-receptors. The latter also display vasodilator actions by blocking α1-adrenoreceptors and activating β3-adrenergic receptors. In addition, thirdgeneration β-blockers exhibit angiogenic, antioxidant, anti-proliferative, anti-hypertrophic and antiapoptotic activities among other effects that are still under investigation.

CONCLUSION

The objective of this review is to describe the evolution observed during the development of the three distinctive generations, thereby highlighting the advantages of third-generation β- blockers over the other two drug classes.

Propranolol treatment prevents chronic central sensitization induced by repeated dural stimulation

Migraine is currently conceptualized as a chronic disease with episodic manifestations. In some patients, migraine attack frequency increases, leading to chronic migraine. Daily preventive therapy is initiated to decrease attack frequency. Propranolol, a first-line medication for migraine prophylaxis, reduces attack frequency in nearly 50% of patients receiving it. However, the mechanisms of its antimigraine action are unclear. We examined the effect of daily propranolol treatment (10 mg·kg per os, 8 days) in a rat model of recurrent activation of dural nociceptors (repeated infusion of an inflammatory soup (IS) on the dura through a cannula every 2-3 days). Propranolol does not abort IS-induced acute cephalic mechanical allodynia but blocks the development of a chronic cutaneous hypersensitivity upon repeated IS injections. Furthermore, propranolol prevents (1) the elevated touch-evoked Fos expression within the trigeminocervical complex, (2) enhanced both spontaneous activity, and evoked responses of second-order trigeminovascular neurons, (3) elevated touch-evoked rostral ventromedial medulla and locus coeruleus Fos expression and (4) diffuse noxious inhibitory controls impairment, induced by repeated IS injections. Our results suggest that propranolol exerts its prophylactic action, at least in part, by blocking the chronic sensitization of descending controls of pain, arising from the rostral ventromedial medulla and locus coeruleus, and in turn preventing the maintenance of a state of facilitated trigeminovascular transmission within the trigeminocervical complex. Assessing changes in these brain areas has the potential to elucidate the mechanisms for migraine transformation and to reveal novel biological and molecular targets for specific migraine-preventive therapies.

Ultrasound-promoted dispersive micro solid-phase extraction of trace anti-hypertensive drugs from biological matrices using a sonochemically synthesized conductive polymer nanocomposite

In this work, a rapid and efficient procedure named ultrasound meliorated dispersive micro solid-phase extraction followed by high performance liquid chromatography-ultra violet detection (US-D-μSPE-HPLC-UV) was developed for the pre-concentration of the main trace anti-hypertensive drugs in complex matrices. The basis of this procedure was a polypyrrole-sodium dodecylbenzenesulfonate/zinc oxide (PPy-DBSNa/ZnO) nanocomposite. It was readily synthesized by the impressive way of in situ sonochemical oxidative polymerization in the presence of some additives such as FeCl₃ and DBSNa, ultimately leading to the effective coating of PPy on the ZnO nanoparticle cores. Characterization of the proposed nanosorbent was performed by different techniques such as FESEM, XRD,EDX, and TGA, confirming the high quality and proper physico-chemical properties of the proposed sorbent. In order to better investigate the input variables, the central composite design (CCD) combined with the desirability function (DF) was utilized. The enriched optimum conditions consisted of the initial pH value of 11.8, 15mg of the PPy-DBSNa/ZnO nanocomposite, a sonication time of 4.6min, and 100μL of methanol, resulting in maximum responses at a relatively low extraction time with a logical DF. Under the optimum conditions, good linearity (5-5000, 2.5-3500, and 2.5-3000ngmL^-1 for metoprolol, propranolol, and carvedilol, respectively, with the correlation of determinations (R²s) higher than 0.99), low limits of detection (LODs) (0.8-1.5ngmL^-1), proper repeatabilities (relative standard deviation values (RSDs) below 6.3%, n=3), reasonable enrichment factors (EFs) (60-72), and good extraction recoveries (ERs) (higher than %75) were obtainable. These appropriate validations corroborated a good effectiveness of ultrasonic waves in the achievement of a supreme solid phase as well as a facile and efficient microextraction of the low therapeutic concentrations in human plasma and urine samples.

Beta-blocker use and fall risk in older individuals: Original results from two studies with meta-analysis

AIMS

To investigate the association between use of β-blockers and β-blocker characteristics - selectivity, lipid solubility, intrinsic sympathetic activity (ISA) and CYP2D6 enzyme metabolism - and fall risk.

METHODS

Data from two prospective studies were used, including community-dwelling individuals, n = 7662 (the Rotterdam Study) and 2407 (B-PROOF), all aged ≥55 years. Fall incidents were recorded prospectively. Time-varying β-blocker use was determined using pharmacy dispensing records. Cox proportional hazard models adjusted for age and sex were applied to determine the association between β-blocker use, their characteristics - selectivity, lipid solubility, ISA and CYP2D6 enzyme metabolism - and fall risk. The results of the studies were combined using meta-analyses.

RESULTS

In total 2917 participants encountered a fall during a total follow-up time of 89 529 years. Meta-analysis indicated no association between use of any β-blocker, compared to nonuse, and fall risk, hazard ratio (HR) = 0.97 [95% confidence interval (CI) 0.88-1.06]. Use of a selective β-blocker was also not associated with fall risk, HR = 0.92 (95%CI 0.83-1.01). Use of a nonselective β-blocker was associated with an increased fall risk, HR = 1.22 (95%CI 1.01-1.48). Other β-blocker characteristics including lipid solubility and CYP2D6 enzyme metabolism were not associated with fall risk.

CONCLUSION

Our study suggests that use of a nonselective β-blocker, contrary to selective β-blockers, is associated with an increased fall risk in an older population. In clinical practice, β-blockers have been shown effective for a variety of cardiovascular indications. However, fall risk should be considered when prescribing a β-blocker in this age group, and the pros and cons for β-blocker classes should be taken into consideration.

Development of a sustained-release microcapsule for delivery of metoprolol succinate

Sustained-release (SR) formulations of metoprolol succinate (MS) may minimize fluctuations in plasma concentration and decrease the resulting adverse events. The aim of the present study was to optimize the loading capacity of microcapsules and the SR of MS. A uniform design method was applied to optimize the formulation of SR microcapsules, composed of ethyl cellulose and polyethylene glycol 6,000, in one step via emulsion-solvent diffusion. In vitro release was studied, and the in vivo bioavailability of MS following dosing with novel microcapsules was compared with a commercially available MS formulation in beagle dogs. The present methodology achieved an entrapment efficiency of 83.2%, with 96.1% of drug released in vitro in 18 h, and the release was close to linear over a 12-h period. Pharmacokinetic studies of MS microcapsules in beagle dogs demonstrated a superior SR profile compared with conventional SR tablets. MS microcapsules were developed with high encapsulation efficiency, which had desirable SR properties in vitro and in vivo.

Synthesis and Determination of Physicochemical Properties of New 3-(4-Arylpiperazin-1-yl)-2-hydroxypropyl 4-Alkoxyethoxybenzoates

Nine new dihydrochloride salts of 3-(4-arylpiperazin-1-yl)-2-hydroxypropyl 4-alkoxyethoxybenzoates were designed and synthesized. The physicochemical properties such as lipophilicity index (log k_w) and dissociation constant (pK_a) were experimentally determined and compared to the software calculated data. The lipophilicity index was determined by means of reversed-phase high performance liquid chromatography (RP-HPLC). The pK_a values were determined by means of capillary zone electrophoresis. The "drug-likeness" properties according to the Lipinski Rule of Five and prediction of possible blood-brain barrier penetration were computed and discussed.

Cardiac safety of ophthalmic timolol

INTRODUCTION

It is generally believed that topical administration of eye drops safeguards against harmful systemic effects. However, about 80% of the drug in the ophthalmic products is systemically absorbed and the first-pass metabolism is avoided. Ophthalmic timolol is widely prescribed in the treatment of glaucoma either alone or in the combination eye drop products, many of which have been launched fairly recently. Ophthalmic timolol may cause serious adverse effects such as symptomatic bradycardia, various conduction disorders in the heart, orthostatic hypotension, syncope and falls. Areas covered: In this review we document a number of factors associated with the properties of ophthalmic timolol and specific features of a patient, which may jeopardize patient's cardiac safety even after topical treatment. Expert opinion: Plasma timolol levels are correlated with cardiovascular adverse effects in patients, since timolol is mainly metabolized by cytochrome P450 2D6 (CYP2D6) enzyme in the liver. Patients who are lacking the functional CYP2D6 or who are concomitantly using potent CYP2D6 inhibitor drugs (e.g. paroxetine or fluoxetine) or verapamil or other beta-blockers are at risk of getting serious cardiac adverse effects. Prior to treatment initiation, ECG should be always performed and CYP2D6 genotyping should be considered, if routinely available.

Partial pharmacologic blockade shows sympathetic connection between blood pressure and cerebral blood flow velocity fluctuations

Cerebral autoregulation (CA) dampens transfer of blood pressure (BP)-fluctuations onto cerebral blood flow velocity (CBFV). Thus, CBFV-oscillations precede BP-oscillations. The phase angle (PA) between sympathetically mediated low-frequency (LF: 0.03-0.15Hz) BP- and CBFV-oscillations is a measure of CA quality. To evaluate whether PA depends on sympathetic modulation, we assessed PA-changes upon sympathetic stimulation with and without pharmacologic sympathetic blockade. In 10 healthy, young men, we monitored mean BP and CBFV before and during 120-second cold pressor stimulation (CPS) of one foot (0°C ice-water). We calculated mean values, standard deviations and sympathetic LF-powers of all signals, and PAs between LF-BP- and LF-CBFV-oscillations. We repeated measurements after ingestion of the adrenoceptor-blocker carvedilol (25mg). We compared parameters before and during CPS, without and after carvedilol (analysis of variance, post-hoc t-tests, significance: p<0.05). Without carvedilol, CPS increased BP, CBFV, BP-LF- and CBFV-LF-powers, and shortened PA. Carvedilol decreased resting BP, CBFV, BP-LF- and CBFV-LF-powers, while PAs remained unchanged. During CPS, BPs, CBFVs, BP-LF- and CBFV-LF-powers were lower, while PAs were longer with than without carvedilol. With carvedilol, CPS no longer shortened resting PA. Sympathetic activation shortens PA. Partial adrenoceptor blockade abolishes this PA-shortening. Thus, PA-measurements provide a subtle marker of sympathetic influences on CA and might refine CA evaluation.

Synthesis and Pharmacological Activity of a New Series of 1-(1H-Indol-4-yloxy)-3-(2-(2-methoxyphenoxy)ethylamino)propan-2-ol Analogs

β-Adrenergic receptor antagonists are important therapeutics for the treatment of cardiovascular disorders. In the group of β-blockers, much attention is being paid to the third-generation drugs that possess important ancillary properties besides inhibiting β-adrenoceptors. Vasodilating activity of these drugs is produced through different mechanisms, such as nitric oxide (NO) release, β2 -agonistic action, α1 -blockade, antioxidant action, and Ca(2+) entry blockade. Here, a study on evaluation of the cardiovascular activity of five new compounds is presented. Compound 3a is a methyl and four of the tested compounds (3b-e) are dimethoxy derivatives of 1-(1H-indol-4-yloxy)-3-(2-(2-methoxyphenoxy)ethylamino)propan-2-ol. The obtained results confirmed that the methyl and dimethoxy derivatives of 1-(1H-indol-4-yloxy)-3-(2-(2-methoxyphenoxy)ethylamino)propan-2-ol and their enantiomers possess α1 - and β1 -adrenolytic activities and that the antiarrhythmic and hypotensive effects of the tested compounds are related to their adrenolytic properties.

Medication-related fall incidents in an older, ambulant population: the B-PROOF study

BACKGROUND

Medication use is a potentially modifiable risk factor for falling; psychotropic and cardiovascular drugs have been indicated as main drug groups that increase fall risk. However, evidence is mainly based on studies that recorded falls retrospectively and/or did not determine medication use at the time of the fall. Therefore, we investigated the associations indicated in the literature between medication use and falls, using prospectively recorded falls and medication use determined at the time of the fall.

METHODS

Data from the B-PROOF (B-vitamins for the prevention of osteoporotic fractures) study were used, concerning community-dwelling elderly aged ≥65 years. We included 2,407 participants with pharmacy dispensing records. During the 2- to 3-year follow-up, participants recorded falls using a fall calendar. Cox proportional hazard models were applied, adjusting for potential confounders including age, sex, health status variables and concomitant medication use.

RESULTS

During follow-up, 1,147 participants experienced at least one fall. Users of anti-arrhythmic medication had an increased fall risk (hazard ratio [HR] 1.61; 95% confidence interval [CI] 1.12-2.32) compared with non-users. Similarly, non-selective beta-blocker use was associated with an increased fall risk (HR 1.41 [95% CI 1.12-1.78]), while statin use was associated with a lower risk (HR 0.81 [95% CI 0.71-0.94]). Benzodiazepine use (HR 1.32 [95% CI 1.02-1.71]), and antidepressant use (HR 1.40 [95% CI 1.07-1.82]) were associated with an increased fall risk. Use of other cardiovascular and psychotropic medication was not associated with fall risk.

CONCLUSION

Our results strengthen the evidence for an increased fall risk in community-dwelling elderly during the use of anti-arrhythmics, non-selective beta-blockers, benzodiazepines, and antidepressant medication. Clinicians should prescribe these drugs cautiously and if possible choose safer alternatives for older patients.

Characterisation of selected active agents regarding pKa values, solubility concentrations and pH profiles by SiriusT3

The aim of this work was to determine pKa values and solubility properties of 34active agents using the SiriusT3 apparatus. The selected drug substances belong to the groups of ACE-inhibitors, β-blockers, antidiabetics and lipid lowering substances. Experimentally obtained pKa and intrinsic solubility values were compared to calculated values (program ACD/ChemSketch) and pKa values to published data as well. Solubility-pH profiles were generated to visualise the substance solubility over the gastrointestinal pH range. The relationship between the solubility characteristic of a substance, its bioavailability and categorisation according to the Biopharmaceutics Classification System (BCS) was examined as well. The results showed a good agreement between experimentally obtained, calculated and published pKa values. The measured and calculated intrinsic solubility values indicated several major deviations. All solubility-pH profiles showed the expected shape and appearance for acids, bases or zwitterionic substances. The obtained results for the pKa and solubility measurements of the examined active agents may help to predict their physicochemical behaviour in vivo, and to understand the bioavailability of the substances according to their BCS categorisation. The easy and reproducible determination of pKa and solubility values makes the SiriusT3 apparatus a useful tool in early stages of drug and formulation development.

Educational paper: therapy of infantile haemangioma--history and current state (part II)

Infantile haemangioma (IH) is the most frequent tumour of infancy. Although it is benign and self-limiting, severe complications can arise due to localisation and fast tumour growth. Also, IHs leave scars after regression in more than half of the cases. Management and therapy of IH have changed greatly after 2008. This update provides an overview of the older therapy options before 2008, which mainly consisted of the administration of corticosteroids, and discusses the modern management with new therapy options such as β-blockers (both systemically and topically).

CONCLUSION

β-blockers are promising and are currently preferred above corticosteroids, but β-blockers still do not give a definitive treatment.

Infantile hemangiomas, retinopathy of prematurity and cancer: a common pathogenetic role of the β-adrenergic system

The serendipitous demonstration that the nonselective β-adrenergic receptor (β-AR) antagonist propranolol promotes the regression of infantile hemangiomas (IHs) aroused interest around the involvement of the β-adrenergic system in angiogenic processes. The efficacy of propranolol was related to the β2-AR blockade and the consequent inhibition of the production of vascular endothelial growth factor (VEGF), suggesting the hypothesis that propranolol could also be effective in treating retinopathy of prematurity (ROP), a retinal pathology characterized by VEGF-induced neoangiogenesis. Consequent to the encouraging animal studies, a pilot clinical trial showed that oral propranolol protects newborns from ROP progression, even though this treatment is not sufficiently safe. Further, animal studies clarified the role of β3-ARs in the development of ROP and, together with several preclinical studies demonstrating the key role of the β-adrenergic system in tumor progression, vascularization, and metastasis, prompted us to also investigate the participation of β3-ARs in tumor growth. The aim of this review is to gather the recent findings on the role of the β-adrenergic system in IHs, ROP, and cancer, highlighting the fact that these different pathologies, triggered by different pathogenic noxae, share common pathogenic mechanisms characterized by the presence of hypoxia-induced angiogenesis, which may be contrasted by targeting the β-adrenergic system. The mechanisms characterizing the pathogenesis of IHs, ROP, and cancer may also be active during the fetal-neonatal development, and a great contribution to the knowledge on the role of β-ARs in diseases characterized by chronic hypoxia may come from research focusing on the fetal and neonatal period.

Autonomic dysfunction in acute ischemic stroke: an underexplored therapeutic area?

Impaired autonomic function, characterized by a predominance of sympathetic activity, is common in patients with acute ischemic stroke. This review describes methods to measure autonomic dysfunction in stroke patients. It summarizes a potential relationship between ischemic stroke-associated autonomic dysfunction and factors that have been associated with worse outcome, including cardiac complications, blood pressure variability changes, hyperglycemia, immune depression, sleep disordered breathing, thrombotic effects, and malignant edema. Involvement of the insular cortex has been suspected to play an important role in causing sympathovagal imbalance, but its exact role and that of other brain regions remain unclear. Although sympathetic overactivity in patients with ischemic stroke appears to be a negative prognostic factor, it remains to be seen whether therapeutic strategies that reduce sympathetic activity or increase parasympathetic activity might improve outcome.

β₁-Adrenoceptor stimulation suppresses endothelial IK(Ca)-channel hyperpolarization and associated dilatation in resistance arteries

BACKGROUND AND PURPOSE

In small arteries, small conductance Ca²⁺-activated K⁺ channels (SK(Ca)) and intermediate conductance Ca²⁺-activated K⁺ channels (IK(Ca)) restricted to the vascular endothelium generate hyperpolarization that underpins the NO- and PGI₂-independent, endothelium-derived hyperpolarizing factor response that is the predominate endothelial mechanism for vasodilatation. As neuronal IK(Ca) channels can be negatively regulated by PKA, we investigated whether β-adrenoceptor stimulation, which signals through cAMP/PKA, might influence endothelial cell hyperpolarization and as a result modify the associated vasodilatation.

EXPERIMENTAL APPROACH

Rat isolated small mesenteric arteries were pressurized to measure vasodilatation and endothelial cell [Ca²⁺]i , mounted in a wire myograph to measure smooth muscle membrane potential or dispersed into endothelial cell sheets for membrane potential recording.

KEY RESULTS

Intraluminal perfusion of β-adrenoceptor agonists inhibited endothelium-dependent dilatation to ACh (1 nM-10 μM) without modifying the associated changes in endothelial cell [Ca²⁺]i . The inhibitory effect of β-adrenoceptor agonists was mimicked by direct activation of adenylyl cyclase with forskolin, blocked by the β-adrenoceptor antagonists propranolol (non-selective), atenolol (β₁) or the PKA inhibitor KT-5720, but remained unaffected by ICI 118 551 (β₂) or glibenclamide (ATP-sensitive K⁺ channels channel blocker). Endothelium-dependent hyperpolarization to ACh was also inhibited by β-adrenoceptor stimulation in both intact arteries and in endothelial cells sheets. Blocking IK(Ca) {with 1 μM 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34)}, but not SK(Ca) (50 nM apamin) channels prevented β-adrenoceptor agonists from suppressing either hyperpolarization or vasodilatation to ACh.

CONCLUSIONS AND IMPLICATIONS

In resistance arteries, endothelial cell β₁-adrenoceptors link to inhibit endothelium-dependent hyperpolarization and the resulting vasodilatation to ACh. This effect appears to reflect inhibition of endothelial IK(Ca) channels and may be one consequence of raised circulating catecholamines.

The anabolic catabolic transforming agent (ACTA) espindolol increases muscle mass and decreases fat mass in old rats

BACKGROUND

Sarcopenia, the age-related, progressive loss of skeletal muscle mass, strength, and function, is a considerable socioeconomic burden by increasing risks of falls, fractures, and frailty. Moreover, sarcopenic patients are often obese and therapeutic options are very limited.

METHODS

Here, we assessed the efficacy of espindolol on muscle mass in 19-month-old male Wistar Han rats (weight, 555 ± 18 g), including safety issues. Rats were randomized to treatment with 3 mg/kg/day espindolol (n = 8) or placebo (n = 14) for 31 days.

RESULTS

Placebo-treated rats progressively lost body weight (-15.5 ± 7.2 g), lean mass (-1.5 ± 4.2 g), and fat mass (-15.6 ± 2.7 g), while espindolol treatment increased body weight (+8.0 ± 6.1 g, p < 0.05), particularly lean mass (+43.4 ± 3.5 g, p < 0.001), and reduced fat mass further (-38.6 ± 3.4 g, p < 0.001). Anabolic/catabolic signaling was assessed in gastrocnemius muscle. Espindolol decreased proteasome and caspase-3 proteolytic activities by approximately 50 % (all p < 0.05). Western blotting showed a reduced expression of key catabolic regulators, including NFκB, MuRF1, and LC-3 (all p < 0.01). The 50- and 26-kDa forms of myostatin were downregulated fivefold and 20-fold, respectively (both p < 0.001). Moreover, 4E-BP-1 was reduced fivefold (p < 0.01), while phospho-PI3K was upregulated fivefold (p < 0.001), although Akt expression and phosphorylation were lower compared to placebo (all p < 0.05). No regulation of p38 and expression of ERK1/2 were observed, while phosphorylation of p38 was reduced (-54 %, p < 0.001) and ERK1/2 was increased (115 and 83 %, respectively, both p < 0.01). Espindolol did not affect cardiac function (echocardiography) or clinical plasma parameters.

CONCLUSION

Espindolol reversed the effects of aging/sarcopenia, particularly loss of muscle mass and increased fat mass. Thus, espindolol is an attractive candidate drug for the treatment of sarcopenia patients.

Role of β-adrenergic receptor signaling and desensitization in heart failure: new concepts and prospects for treatment

The use of beta-blockers to antagonize beta-adrenergic receptor signaling in the heart has become a standard method of treatment for heart failure, resulting in positive clinical outcomes alone and in conjunction with other modulators of cardiomyocyte contractility. However, an entire explanation for improved cardiac function in patients using beta-blockers is unknown, and in fact may be quite complicated, considering the numerous intracellular signaling pathways associated with beta-adrenergic receptors. Stimulation of beta-adrenergic receptors during both normal conditions and during heart failure activate several distinct signaling cascades, which influence cardiomyocyte contraction, hypertrophy and apoptosis. This review explores the signaling cascades induced by beta-adrenergic receptor activation in normal and desensitized states to provide new insight into the effective treatment of cardiac dysfunction.

Propranolol for infantile hemangioma (PINCH): an open-label trial to assess the efficacy of propranolol for treating infantile hemangiomas and for determining the decline in heart rate to predict response to propranolol

BACKGROUND

Propranolol has emerged as front-line therapy for infantile hemangiomas (IHs). However, a well-defined protocol for administering and predicting response to propranolol is unavailable.

METHODS

In this open-label trial, 31 children with IH (median age=5 mo; range,1 mo to 9 y) were administered propranolol (2 mg/kg/d) for a median duration of 28 weeks (12 to 50 wk). They were compared with 14 historical controls with IH who did not receive any treatment. An image-based scoring system was used to assess involution.

RESULTS

Propranolol (28/31, 90.3%) produced better and faster response compared with control treatment (4/14, 28.6%). With propranolol, 65% to 80% involution was obtained in the first 8 weeks, with an additional 2% to 10% involution until 20 weeks. After 20 weeks, the changes in IH were insignificant. Response was more pronounced among infants ≤6 months of age who attained a peak involution score of 1.86, suggesting >80% involution of IH. The similar score in the cohort aged 6 to 36 months was 3.31. The heart rate (HR) decline after propranolol treatment was significantly higher among patients whose hemangioma responded to propranolol than in those who did not respond (P=0.0006). Decline in HR by >20%, 2 weeks after propranolol administration, was predictive of IH involution (relative risk=0.11; 95% confidence interval, 0.02-0.51; P=0.036).

CONCLUSIONS

Propranolol is efficacious in patients with IH. The most pronounced response is seen in the first 8 weeks and in infants aged 6 months or younger. A decline in HR >20% is an early marker of response to propranolol.

Mechanisms of diabetic complications

It is increasingly apparent that not only is a cure for the current worldwide diabetes epidemic required, but also for its major complications, affecting both small and large blood vessels. These complications occur in the majority of individuals with both type 1 and type 2 diabetes. Among the most prevalent microvascular complications are kidney disease, blindness, and amputations, with current therapies only slowing disease progression. Impaired kidney function, exhibited as a reduced glomerular filtration rate, is also a major risk factor for macrovascular complications, such as heart attacks and strokes. There have been a large number of new therapies tested in clinical trials for diabetic complications, with, in general, rather disappointing results. Indeed, it remains to be fully defined as to which pathways in diabetic complications are essentially protective rather than pathological, in terms of their effects on the underlying disease process. Furthermore, seemingly independent pathways are also showing significant interactions with each other to exacerbate pathology. Interestingly, some of these pathways may not only play key roles in complications but also in the development of diabetes per se. This review aims to comprehensively discuss the well validated, as well as putative mechanisms involved in the development of diabetic complications. In addition, new fields of research, which warrant further investigation as potential therapeutic targets of the future, will be highlighted.

Autonomic blockade during sinusoidal baroreflex activation proves sympathetic modulation of cerebral blood flow velocity

BACKGROUND AND PURPOSE

Pharmacological blockade showed sympathetic origin of 0.03 to 0.15 Hz blood pressure (BP) oscillations and parasympathetic origin of 0.15 to 0.5 Hz RR-interval (RRI) oscillations, but has not been used to determine origin of cerebral blood flow velocity (CBFV) oscillations at these frequencies. This study evaluated by pharmacological blockade whether 0.1 Hz CBFV oscillations are related to sympathetic and 0.2 Hz CBFV oscillations to parasympathetic modulation.

METHODS

In 11 volunteers (24.6 ± 2.3 years), we monitored RRIs, BP, and proximal middle cerebral artery CBFV, at rest, during 180 s sympathetic BP activation by 0.1 Hz sinusoidal neck suction (NS), and during 180 s parasympathetic RRI activation by 0.2 Hz NS. We repeated recordings after 25 mg carvedilol, and after 0.04 mg/kg atropine. Autoregressive analysis quantified RRI-, BP-, and CBFV-spectral powers at 0.1 Hz and 0.2 Hz. We compared parameters at rest, during 0.1 Hz, or 0.2 Hz NS, with and without carvedilol or atropine (analysis of variance, post hoc testing; significance, P<0.05).

RESULTS

Carvedilol significantly increased RRIs and lowered BP, CBFV, and 0.1 Hz RRI-, BP-, and CBFV-powers at baseline (P=0.041 for CBFV-powers), and during 0.1 Hz NS-induced sympathetic activation (P<0.05). At baseline and during 0.2 Hz NS-induced parasympathetic activation, atropine lowered RRIs and 0.2 Hz RRI-powers, but did not change BP, CBFV, and 0.2 Hz BP- and CBFV-powers.

CONCLUSIONS

Attenuation of both 0.1 Hz CBFV and BP oscillations after carvedilol indicates a direct relation between 0.1 Hz CBFV oscillations and sympathetic modulation. Absent effects of atropine on BP, CBFV, and 0.2 Hz BP and CBFV oscillations suggest that there is no direct parasympathetic influence on 0.2 Hz BP and CBFV modulation.