Central Effects of Beta-Blockers May Be Due to Nitric Oxide and Hydrogen Peroxide Release Independently of Their Ability to Cross the Blood-Brain Barrier

Peripheral to brain and hippocampus crosstalk induced by exercise mediates cognitive and structural hippocampal adaptations

Endurance exercise leads to robust increases in memory and learning. Several exercise adaptations occur to mediate these improvements, including in both the hippocampus and in peripheral organs. Organ crosstalk has been becoming increasingly more present in exercise biology, and studies have shown that peripheral organs can communicate to the hippocampus and mediate hippocampal changes. Both learning and memory as well as other hippocampal functional-related changes such as neurogenesis, cell proliferation, dendrite morphology and synaptic plasticity are controlled by these exercise responsive peripheral proteins. These peripheral factors, also called exerkines, are produced by several organs including skeletal muscle, liver, adipose tissue, kidneys, adrenal glands and circulatory cells. Previous reviews have explored some of these exerkines including muscle-derived irisin and cathepsin B (CTSB), but a full picture of peripheral to hippocampus crosstalk with novel exerkines such as selenoprotein 1 (SEPP1) and platelet factor 4 (PF4), or old overlooked ones such as lactate and insulin-like growth factor 1 (IGF-1) is still missing. We provide 29 different studies of 14 different exerkines that crosstalk with the hippocampus. Thus, the purpose of this review is to explore peripheral exerkines that have shown to exert hippocampal function following exercise, demonstrating their particular effects and molecular mechanisms in which they could be inducing adaptations.

Adrenergic receptors blockade alleviates dexamethasone-induced neurotoxicity in adult male Wistar rats: Distinct effects on β-arrestin2 expression and molecular markers of neural injury

BACKGROUND

Dexamethasone-induced neurotoxicity has been previously reported. However, the molecular mechanisms are still not completely understood.

OBJECTIVES

The current work aimed to investigate the modulatory effects of α- and β-adrenergic receptors on dexamethasone-induced neurotoxicity in rats focused on changes in β-arrestin2 and molecular markers of neural injury in cerebral cortex.

METHODS

Male Wistar rats were subcutaneously injected with dexamethasone (10 mg/kg/day) for 7 days to induce neural injury in the cerebral cortex. The experiment involved 5 groups: control, dexamethasone, carvedilol, propranolol, and doxazosin. In the last 3 groups, drugs were given 2 hours before dexamethasone injection. At the end of experiment, brain samples were collected for measurement of brain derived neurotrophic factor (BDNF), glial fibrillary acidic protein (GFAP), kinase activity of protein kinase B (Akt), diacylglycerol (DAG), α-smooth muscle actin (α-SMA), Smad3, β-amyloid and phospho-tau protein levels in addition to histopathological examination of brain tissue using hematoxylin-eosin, Nissl, and Sirius red stains. Moreover, β-arrestin2 levels in the cerebral cortex were measured using immunohistochemical examination.

RESULTS

Dexamethasone slightly reduced brain weight and significantly decreased BDNF, Akt kinase activity and β-arrestin2 but markedly induced degeneration of cortical neurons and significantly increased GFAP, DAG, α-SMA, Smad3, β-amyloid and phospho-tau protein levels compared to controls. Carvedilol, propranolol, and doxazosin reversed all dexamethasone-induced molecular changes and slightly ameliorated the histopathological changes. Carvedilol significantly increased brain weight and β-arrestin2 levels compared to dexamethasone, propranolol, and doxazosin groups.

CONCLUSION

blocking α- and/or β-adrenergic receptors alleviate dexamethasone-induced neurotoxicity despite their distinct effects on β-arrestin2 levels in the cerebral cortex.

Integrated metabolomics analysis reveals mechanistic insights into variability in blood pressure response to thiazide diuretics and beta blockers

Hypertensive patients with a higher proportion of genetic West African ancestry (%GWAA) have better blood pressure (BP) response to thiazide diuretics (TDs) and worse response to β-blockers (BBs) than those with lower %GWAA, associated with their lower plasma renin activity (PRA). TDs and BBs are suggested to reduce BP in the long term through vasodilation via incompletely understood mechanisms. This study aimed at identifying pathways underlying ancestral differences in PRA, which might reflect pathways underlying BP-lowering mechanisms of TDs and BBs. Among hypertensive participants enrolled in the Pharmacogenomics Evaluation of Antihypertensive Responses (PEAR) and PEAR-2 trials, we previously identified 8 metabolites associated with baseline PRA and 4 metabolic clusters (including 39 metabolites) that are different between those with GWAA <45% versus ≥45%. In the current study, using Ingenuity Pathway Analysis (IPA), we integrated these signals. Three overlapping metabolic signals within three significantly enriched pathways were identified as associated with both PRA and %GWAA: ceramide signaling, sphingosine 1- phosphate signaling, and endothelial nitric oxide synthase signaling. Literature indicates that the identified pathways are involved in the regulation of the Rho kinase cascade, production of the vasoactive agents nitric oxide, prostacyclin, thromboxane A2, and endothelin 1; the pathways proposed to underlie TD- and BB-induced vasodilatation. These findings may improve our understanding of the BP-lowering mechanisms of TDs and BBs. This might provide a possible step forward in personalizing antihypertensive therapy by identifying patients expected to have robust BP-lowering effects from these drugs.

Infantile hemangioma: the common and enigmatic vascular tumor

Infantile hemangioma (IH) is a benign vascular tumor that occurs in 5% of newborns. The tumor follows a life cycle of rapid proliferation in infancy, followed by slow involution in childhood. This unique life cycle has attracted the interest of basic and clinical scientists alike as a paradigm for vasculogenesis, angiogenesis, and vascular regression. Unanswered questions persist about the genetic and molecular drivers of the proliferating and involuting phases. The beta blocker propranolol usually accelerates regression of problematic IHs, yet its mechanism of action on vascular proliferation and differentiation is unclear. Some IHs fail to respond to beta blockers and regrow after discontinuation. Side effects occur and long-term sequelae of propranolol treatment are unknown. This poses clinical challenges and raises novel questions about the mechanisms of vascular overgrowth in IH.

Psychiatric sequelae of traumatic brain injury - future directions in research

Despite growing appreciation that traumatic brain injury (TBI) is an important public health burden, our understanding of the psychiatric and behavioural consequences of TBI remains limited. These changes are particularly detrimental to a person's sense of self, their relationships and their participation in the wider community, and they continue to have devastating individual and cumulative effects long after TBI. This Review relates specifically to TBIs that confer objective clinical or biomarker evidence of structural brain injury; symptomatic head injuries without such evidence are outside the scope of this article. Common psychiatric, affective and behavioural sequelae of TBI and their proposed underlying mechanisms are outlined, along with a brief overview of current treatments. Suggestions for how scientists and clinicians can work together in the future to address the chasms in clinical care and knowledge are discussed in depth.

The impact of propranolol on the growth and development of children with proliferative infantile hemangioma during treatment

Oral propranolol has not been shown to impact physical development, such as weight and height. The impact of children's intellectual development has received relatively little attention from researchers. The effects of propranolol on the growth and development of children with proliferative infantile hemangiomas during treatment were analyzed retrospectively. The children with infantile hemangioma treated with oral propranolol in the Department of Burn and Plastic Surgery, Fuzhou Children's Hospital of Fujian Province, from February 2017 to May 2022 were analyzed. A uniform therapeutic regimen was applied, including assessment, treatment, and follow-up. The assessment included physical development and intellectual development indices. The physical development indices were height and weight. Neuropsychological assessment uses developmental quotient (DQ) to assess intelligence development. The DQs on months 3, 6, and 9 posttreatment were compared to the pretreatment. Wilcoxon rank sum test of paired samples was used for height and weight. The developmental quotient was determined by paired t test. P < .05 indicated significant difference. A total of 51 patients were enrolled. All children completed the treatment successfully, without severe adverse drug reactions leading to treatment discontinuation. There was no significant difference in height and weight before and after treatment (P > .05). No significant difference was detected in DQ 3 months posttreatment and pretreatment (P = .19), while it decreased at 6 and 9 months posttreatment (P < .05). Oral propranolol does not have an impact on physical development (height and weight). No short-term effect was found on intellectual development, but a decrease was noted over 6 months, which needs to be investigated further.

The effect of early and long-term propranolol therapy on learning and memory in mice

Propranolol is the treatment of choice for infantile hemangioma. We investigated the effects of long-term propranolol use in early infancy on learning and memory later in life in mice. At three weeks of age, mice were randomly divided into six experimental groups. Groups 1 and 2 (controls) received only saline for 21 days. Groups 3 and 4 received propranolol (2.5 mg/kg) for 21 days. Groups 5 and 6 received propranolol (5 mg/kg) for 21 days. Groups 1, 3 and 5 were tested at the end of 21 days of treatment (week 6). However, groups 2, 4 and 6 received a 2-week break and then (week 8) exposed to tests. In the Morris water maze test, propranolol (2.5 and 5 mg/kg) dose-dependently increased the time spent in the target quadrant in mice at weeks 6 and 8. However, propranolol did not affect the swimming speed in both time periods. There were no significant effects of propranolol on the number of errors evaluated during the radial arm maze tests. In conclusion, long-term use of propranolol in early infancy did not disrupt the learning and memory of mice.

Ranugha PS, Seetharam KA. IADVL SIG pediatric dermatology (academy) recommendations on Hemangioma of Infancy (HOI)

Hemangioma of infancy (HOI) is a benign vascular proliferation. Though resolution is the norm, potential complications make an accurate diagnosis and early management of importance. The Indian association of dermatologists, venereologists and leprologists (IADVL) special interest group (SIG) paediatric dermatology in association with IADVL academy did an extensive analysis of the literature on the clinical features, diagnosis, and management of HOI published between 2010 and 2021. Online meetings were conducted from February 2021 to March 2022 to reach a consensus on these recommendations which are made from an Indian perspective.

Propranolol Modulates Cerebellar Circuit Activity and Reduces Tremor

Tremor is the most common movement disorder. Several drugs reduce tremor severity, but no cures are available. Propranolol, a β-adrenergic receptor blocker, is the leading treatment for tremor. However, the in vivo circuit mechanisms by which propranolol decreases tremor remain unclear. Here, we test whether propranolol modulates activity in the cerebellum, a key node in the tremor network. We investigated the effects of propranolol in healthy control mice and Car8^wdl/wdl mice, which exhibit pathophysiological tremor and ataxia due to cerebellar dysfunction. Propranolol reduced physiological tremor in control mice and reduced pathophysiological tremor in Car8^wdl/wdl mice to control levels. Open field and footprinting assays showed that propranolol did not correct ataxia in Car8^wdl/wdl mice. In vivo recordings in awake mice revealed that propranolol modulates the spiking activity of control and Car8^wdl/wdl Purkinje cells. Recordings in cerebellar nuclei neurons, the targets of Purkinje cells, also revealed altered activity in propranolol-treated control and Car8^wdl/wdl mice. Next, we tested whether propranolol reduces tremor through β₁ and β₂ adrenergic receptors. Propranolol did not change tremor amplitude or cerebellar nuclei activity in β₁ and β₂ null mice or Car8^wdl/wdl mice lacking β₁ and β₂ receptor function. These data show that propranolol can modulate cerebellar circuit activity through β-adrenergic receptors and may contribute to tremor therapeutics.

Metoprolol Inhibits Developmental Brain Sterol Biosynthesis in Mice

De novo sterol synthesis is a critical homeostatic mechanism in the brain that begins during early embryonic development and continues throughout life. Multiple medications have sterol-biosynthesis-inhibiting side effects, with potentially detrimental effects on brain health. Using LC-MS/MS, we investigated the effects of six commonly used beta-blockers on brain sterol biosynthesis in vitro using cell lines. Two beta-blockers, metoprolol (MTP) and nebivolol, showed extreme elevations of the highly oxidizable cholesterol precursor 7-dehydrocholesterol (7-DHC) in vitro across multiple cell lines. We followed up on the MTP findings using a maternal exposure model in mice. We found that 7-DHC was significantly elevated in all maternal brain regions analyzed as well as in the heart, liver and brain of the maternally exposed offspring. Since DHCR7-inhibiting/7-DHC elevating compounds can be considered teratogens, these findings suggest that MTP utilization during pregnancy might be detrimental for the development of offspring, and alternative beta-blockers should be considered.

Medical Management of Infantile Hemangiomas: An Update

Infantile hemangioma (IH) is the most common benign vascular tumor of infancy, affecting about 5% of infants. It has a characteristic growth pattern of early rapid proliferation followed by progressive involution. Although most IH evolve favorably, complications are observed in 10-15% of cases, justifying treatment. For over 10 years now, propranolol has become the first-line therapy for complicated IH, revolutionizing their management and their prognosis. In this article, we review the clinical features, associations, complications/sequelae and therapeutic approaches for IH, focusing on current medical therapy. Indications for treatment and various treatment options, including propranolol and other oral β-blockers, topical timolol, and corticosteroids are presented. Current controversies regarding oral propranolol such as pre-treatment screening, in- vs out-patient initiation of treatment, early and potential long-term side effects and recommended monitoring are discussed.

Drug Delivery Challenges in Brain Disorders across the Blood-Brain Barrier: Novel Methods and Future Considerations for Improved Therapy

Due to the physiological and structural properties of the blood-brain barrier (BBB), the delivery of drugs to the brain poses a unique challenge in patients with central nervous system (CNS) disorders. Several strategies have been investigated to circumvent the barrier for CNS therapeutics such as in epilepsy, stroke, brain cancer and traumatic brain injury. In this review, we summarize current and novel routes of drug interventions, discuss pharmacokinetics and pharmacodynamics at the neurovascular interface, and propose additional factors that may influence drug delivery. At present, both technological and mechanistic tools are devised to assist in overcoming the BBB for more efficient and improved drug bioavailability in the treatment of clinically devastating brain disorders.

Infantile Hemangiomas: An Update on Pathogenesis and Treatment

Infantile hemangiomas are the most common benign vascular tumors in infancy. This review includes an update on the current knowledge on pathogenesis, a discussion on indications for treatment, and a review of the mechanisms underlying the different treatment methods. Although most infantile hemangiomas require only active observation because of their natural course, which results in involution, about 10% present with complications that require immediate treatment. The basic treatment includes systemic and topical options. In cases of insufficient response or rebound growth, other forms of treatment should be considered. In some cases, combined therapy might be initiated.

Infantile hemangioma. Part 2: Management

The majority of infantile hemangiomas (IH) can be managed conservatively, but for those requiring active treatment, management has been revolutionized in the last decade by the discovery of propranolol. Patients that may require active intervention should receive specialist review, ideally before 5 weeks of age to mitigate the risk of sequelae. Propranolol can commence for most infants in the outpatient setting and the most frequently employed dosing regimen is 1 mg/kg twice daily. In the future, β-blockers with a more-selective mechanism of action, such as atenolol, show some promise. In recalcitrant lesions, systemic corticosteroids or sirolimus may be considered. For small, superficial IHs, topical timolol maleate or pulsed dye laser may be considered. Where the IH involutes with cutaneous sequelae, a range of interventions have been reported, including surgery, laser, and embolization. IHs have a well-described clinical trajectory and are readily diagnosed and managed via telemedicine. Algorithms have been constructed to stratify those patients who can be managed remotely from those who warrant in-person review during the COVID-19 pandemic.

Efficacy and Safety of Propranolol vs Atenolol in Infants With Problematic Infantile Hemangiomas: A Randomized Clinical Trial

Importance

Propranolol has become the first-line therapy for problematic infantile hemangiomas (IHs) that require systemic therapy. However, different adverse events have been reported during propranolol treatment. The positive efficacy and safety of atenolol raise the question of whether it could be used as a promising therapy for IH.

Objective

To compare the efficacy and safety of propranolol vs atenolol in infants (between age 5 and 20 weeks) with problematic IHs who required systemic therapy.

Design, Setting, and Participants

This was a prospective, multicenter, randomized, controlled, open-label clinical trial conducted in collaboration among 6 separate investigation sites in China from February 1, 2015, to December 31, 2018. A total of 377 patients met the criteria for inclusion and were randomized to the propranolol (190 [50.4%]) and atenolol (187 [49.6%]) groups. Data were analyzed in June 2020.

Interventions

Participants were randomized to receive either propranolol or atenolol for at least 6 months. They completed efficacy assessments at 2 years after the initial treatment.

Main Outcomes and Measures

The primary outcome was any response or nonresponse at 6 months. The key secondary outcome was changes in the hemangioma activity score.

Results

Of 377 participants, 287 (76.1%) were female, and the mean (SD) age was 10.2 (4.0) weeks in the propranolol group and 9.8 (4.1) weeks in the atenolol group. After 6 months of treatment, in the propranolol and atenolol groups, the overall response rates were 93.7% and 92.5%, respectively (difference, 1.2%; 95% CI, -4.1% to 6.6%). At 1 and 4 weeks after treatment, and thereafter, the hemangioma activity score in the atenolol group aligned with the propranolol group (odds ratio, 1.034; 95% CI, 0.886-1.206). No differences between the propranolol group and atenolol group were observed in successful initial responses, quality of life scores, complete ulceration healing times, or the rebound rate. Both groups presented a similar percentage of complete/nearly complete responses at 2 years (82.1% vs 79.7%; difference, 2.4%; 95% CI, -5.9% to 10.7%). Adverse events were more common in the propranolol group (70.0% vs 44.4%; difference, 25.6%; 95% CI, 15.7%-34.8%), but the frequency of severe adverse events did not differ meaningfully between the groups.

Conclusions and Relevance

In this randomized clinical trial, when compared with propranolol, atenolol had similar efficacy and fewer adverse events in the treatment of infants with problematic IHs. The results suggest that oral atenolol can be used as an alternative treatment option for patients with IH who require systemic therapy.

Trial Registration

ClinicalTrial.gov Identifier: NCT02342275.

Sleep behavior of infants with infantile hemangioma treated with propranolol-a cohort study

Sleep problems are frequently reported in infants treated with propranolol for infantile hemangiomas, possibly serving as a marker for a negative impact on central nervous system function. In this cohort study, we objectively investigate the sleep behavior of infants with infantile hemangiomas on propranolol compared to a healthy, untreated control group. Sleep of propranolol-treated infants and controls was investigated using ankle actigraphy and a 24-h diary for 7-10 days at ages 3 and 6 months. The main outcome measures were the Number of Nighttime Awakenings and Sleep Efficiency. The main secondary outcome measures included 24-hour Total Sleep, daytime sleep behavior, and parent-rated infant sleep quality and behavioral development based on the Brief Infant Sleep Questionnaire (BISQ) and the age-appropriate Ages-and-Stages Questionnaire (ASQ), respectively. Fifty-four term-born infants were included in each cohort. No group difference in any investigated parameter was seen at age 3 months. At age 6 months, the propranolol group exhibited a decrease in Sleep Efficiency and a trend towards an increased Number of Nighttime Awakenings compared to the control group. Treated infants at 6 months also had shorter daytime waking periods. 24-hour Total Sleep was unaffected by propranolol. No negative impact of propranolol on subjective sleep quality and behavioral development was noted.Conclusion: Propranolol exerts a measurable yet mild impact on objectively assessed infants' sleep measures. Behavioral developmental scores were unaffected. Our results support propranolol as first-line therapy for complicated infantile hemangiomas. What is Known: • Sleep disorders are frequently reported in infants with infantile hemangiomas treated with propranolol and often lead to treatment discontinuation. • Investigations of the sleep pattern in this patient group using objective measures are lacking. What is New: • The sleep pattern of propranolol-treated infants is assessed using actigraphy and a 24-h sleep diary and compared to healthy, untreated controls. • Propranolol leads to a decreased sleep efficiency at night and an increased demand of daytime sleep, yet effects are mild overall.

Antihypertensive Drugs and Risk of Depression: A Nationwide Population-Based Study

Hypertension, cardiovascular diseases, and cerebrovascular diseases are associated with an increased risk of depression, but it remains unclear whether treatment with antihypertensive agents decreases or increases this risk. The effects of individual drugs are also unknown. We used Danish population-based registers to systematically investigate whether the 41 most used individual antihypertensive drugs were associated with an altered risk of incident depression. Analyses of diuretics were included for comparisons. Participants were included in the study in January 2005 and followed until December 2015. Two different outcome measures were included: (1) a diagnosis of depressive disorder at a psychiatric hospital as an inpatient or outpatient and (2) a combined measure of a diagnosis of depression or use of antidepressants. Continued use of classes of angiotensin agents, calcium antagonists, and β-blockers was associated with significantly decreased rates of depression, whereas diuretic use was not. Individual drugs associated with decreased depression included 2 of 16 angiotensin agents: enalapril and ramipril; 3 of 10 calcium antagonists: amlodipine, verapamil, and verapamil combinations; and 4 of 15 β-blockers: propranolol, atenolol, bisoprolol, and carvedilol. No drug was associated with an increased risk of depression. In conclusion, real-life population-based data suggest a positive effect of continued use of 9 individual antihypertensive agents. This evidence should be used in guiding prescriptions for patients at risk of developing depression including those with prior depression or anxiety and patients with a family history of depression.

Blood-brain barrier dysfunction: the undervalued frontier of hypertension

The blood-brain barrier (BBB) constitutes the complex anatomic and physiologic interface between the intravascular compartment and the central nervous system, and its integrity is paramount for the maintenance of the very sensitive homeostasis of the central nervous system. Arterial hypertension is a leading cause of morbidity and mortality. The BBB has been shown to be disrupted in essential hypertension. BBB integrity is important for central autonomic control and this may be implicated in the pathophysiology of hypertension. On the other hand, evidence from experimental studies indicates that BBB disruption can be present in both hypertensive disease and dementia syndromes, suggesting a possibly key position of loss of BBB integrity in the pathophysiological pathways linking arterial hypertension with cognitive decline. Although much still remains to be elucidated with respect to the exact underlying mechanisms, the discovery of novel pathological pathways has changed our understanding of adult dementia and central nervous system disease overall, pointing out-in parallel-new potential therapeutic targets. The aim of this review is to summarize current scientific knowledge relevant to the pathophysiologic pathways that are involved in the disruption of the BBB function and potentially mediate hypertension-induced cognitive impairment. In parallel, we underline the differential cognition-preserving effect of several antihypertensive agents of similar blood pressure-lowering capacity, highlighting the presence of previously under-recognized BBB-protective actions of these drugs.

The β2-adrenergic receptor-ROS signaling axis: An overlooked component of β2AR function?

β2-Adrenergic receptor (β2AR) agonists are clinically used to elicit rapid bronchodilation for the treatment of bronchospasms in pulmonary diseases such as asthma and COPD, both of which exhibit characteristically high levels of reactive oxygen species (ROS); likely secondary to over-expression of ROS generating enzymes and chronically heightened inflammation. Interestingly, β2AR has long-been linked to ROS, yet the involvement of ROS in β2AR function has not been as vigorously studied as other aspects of β2AR signaling. Herein, we discuss the existing body of evidence linking β2AR activation to intracellular ROS generation and importantly, the role of ROS in regulating β2AR function. The reciprocal interplay of the β2AR and ROS appear to endow this receptor with the ability to self-regulate signaling efficacy and ligand binding, hereby unveiling a redox-axis that may be unfavorably altered in pathological states contributing to both disease progression and therapeutic drug responses.