Search Results (38)

Liver cirrhosis is a chronic progressive disease marked by the transition from a compensated to a decompensated stage, associated with severe complications. Central to this progression is portal hypertension, which results from increased intrahepatic vascular resistance and endothelial dysfunction, as well as splanchnic vasodilation and an augmented circulatory state. Non-selective beta-blockers (NSBBs) remain the standard of care for portal hypertension, reducing portal pressure by lowering cardiac output via beta-1 receptor blockade and decreasing splanchnic blood flow through beta-2 receptor antagonism. However, clinical application of NSBBs is often hindered by adverse effects such as bradycardia, hypotension, and fatigue, alongside inconsistent efficacy in certain patient populations. Such limitations have driven the search for alternative therapeutic strategies and effective biomarkers for identifying non-responders. Beta-3 adrenergic receptor agonists have emerged as promising candidates, acting through distinct mechanisms, different from NSBBs. By stimulating nitric oxide release from endothelial cells, beta-3 agonists induce selective vasodilation without negatively impacting cardiac function, potentially overcoming the limitations of traditional therapies. This review discusses the molecular pathways of NSBBs, their clinical role and limitations, introduces potential novel biomarkers, and highlights the growing evidence supporting beta-3 receptor agonists as novel and targeted treatments for portal hypertension. Full article

Obesity is defined as abnormal or excessive accumulation of body fat and contributes to several metabolic disorders. White adipose tissue (WAT) releases energy as free fatty acids and glycerol from triglycerides through a process called lipolysis. People with obesity have impaired catecholamine-stimulated lipolysis, but comprehensive understanding of this lipolysis is still unclear. We previously showed that expression of WW domain-containing E3 ubiquitin ligase 1 (WWP1), a member of the HECT-type E3 family of ubiquitin ligases, was increased in WAT of obese mice. In this study, we generated Wwp1 knockout (KO) mice to evaluate the effect of WWP1 in WAT of obese mice. The mRNA levels of beta-3 adrenergic receptor (Adrb3), which were decreased with a high-fat diet, were increased by Wwp1 KO in WAT. Moreover, Wwp1 KO mice showed increased phosphorylated hormone-sensitive lipase levels in WAT. In contrast, noradrenaline and its metabolism were not altered in WAT of obese Wwp1 KO mice. These findings indicate that WWP1, which is increased in adipocytes because of obesity, is a candidate for suppressing lipolysis independently of noradrenaline metabolism. We anticipate that inhibition of WWP1 is a promising approach for a new treatment of obesity and type-2 diabetes using Adrb3 agonists. Full article

The beta-3 adrenergic receptor (β3-AR), whose expression is modulated by oxygen levels, was found to play a key role in organ maturation, and its agonism was reported to mitigate hyperoxia-induced large bowel damage by preventing organ hypoplasia, preserving epithelial integrity, vascularization, and the neurochemical coding in the colonic myenteric plexus. This study explored the effects of β3-AR agonism in preventing hyperoxia-related alterations on the ileal enteric nervous system (ENS). Sprague–Dawley rat pups were reared under normoxia or hyperoxia (85%) during the first two weeks after birth and treated or not with the β3-AR agonist BRL37344 at 1, 3, or 6 mg/kg. Hyperoxia caused an imbalance of inhibitory nitrergic and excitatory cholinergic neurons in both the myenteric and submucosal plexuses and decreased the amounts of neurons in the submucosal plexus and that of S100β⁺ and GFAP⁺ glial cells in the myenteric plexus. Administration of 3 mg/kg BRL37344 preserved the neuronal chemical coding and partially prevented the loss of myenteric GFAP⁺ glial cells, while it did not counteract submucosal neuronal loss. Our findings indicate the potential of β3-AR agonism as a new therapeutic strategy for hyperoxia-induced ileal ENS alterations. Full article

Background and Clinical Significance: When lactate production surpasses the body’s clearance capacity, hyperlactatemia (lactate ≥ 2 mmol/L) or lactic acidosis (lactate ≥ 4 mmol/L) can develop. Lactic acidosis is classified into type A, which arises from regional or global tissue hypoperfusion, and type B, resulting from metabolic disturbances without tissue hypoxia. Type A lactic acidosis, often associated with conditions like sepsis or shock, is a critical marker of life-threatening conditions, whereas type B lactic acidosis is less frequently recognized in clinical practice. Case Presentation: A 95-year-old man presents with an asthma exacerbation and is treated with an albuterol inhaler. However, he is found to have persistently high lactate levels. Further investigation reveals a congenital intrahepatic portosystemic shunt on imaging. This, in conjunction with the ongoing use of beta-adrenergic receptor agonists, contributes to the development of type B lactic acidosis. Conclusions: The impact of lactic acidosis depends on its severity and clinical context. While beta agonists are a recognized cause of type B lactic acidosis, a potential role for structural liver abnormalities in reduced lactate clearance must be examined further. Full article

Neurodegenerative diseases are currently among the most devastating diseases with no effective disease-modifying drugs in the market, with Alzheimer’s disease (AD) being the most prevalent. AD is a complex multifactorial neurodegenerative disorder characterized by progressive and severe cognitive impairment and memory loss. It is the most common cause of progressive memory loss (dementia) in the elderly, and to date, there is no effective treatment to cure or slow disease progression substantially. The role of adrenergic receptors in the pathogenesis of Alzheimer’s disease and other tauopathies is poorly understood or investigated. Recently, some studies indicated a potential benefit of drugs acting on the adrenergic receptors for AD and dementias, although due to the heterogeneity of the drug classes used, the results on the whole remain inconclusive. The scope of this review article is to comprehensively review the literature on the possible role of adrenergic receptors in neurodegenerative diseases, stemming from the use of agonists and antagonists including antihypertensive and asthma drugs acting on the adrenergic receptors, but also from animal models and in vitro models where these receptors have been studied. Ultimately, we hope to obtain a better understanding of the role of these receptors, identify the gaps in knowledge, and explore the possibility of repurposing such drugs for AD, given their long history of use and safety. Full article

During the perioperative period of transplantation, patients experience hypotension secondary to the side effects of anesthesia, surgical stress, inflammatory triggering, and intraoperative fluid shifts, among others causes. Vasopressor support, in this context, must reverse systemic hypotension, but ideally, the agents used should benefit allograft function and avoid the adverse events commonly seen after transplantation. Traditional therapies to reverse hypotension include catecholamine vasopressors (norepinephrine, epinephrine, dopamine, and phenylephrine), but their utility is limited when considering allograft complications and adverse events such as arrhythmias with agents with beta-adrenergic properties. Synthetic angiotensin II (AT2S–[Giapreza]) is a novel vasopressor indicated for distributive shock with a unique mechanism of action as an angiotensin receptor agonist restoring balance to an often-disrupted renin angiotensin aldosterone system. Additionally, AT2S provides a balanced afferent and efferent arteriole vasoconstriction at the level of the kidney and could avoid the arrhythmic complications of a beta-adrenergic agonist. While the data, to date, are limited, AT2S has demonstrated safety in case reports, pilot studies, and small series in the kidney, liver, heart, and lung transplant populations. There are physiologic and hemodynamic reasons why AT2S could be a more utilized agent in these populations, but further investigation is warranted. Full article

In frail older adults (mean age 85 years old), a 3-month supplementation with a low dose (6 g/day) of medium-chain triglycerides (MCTs; C8:0 and C10:0) given at a meal increased muscle mass and function, relative to supplementation with long-chain triglycerides (LCTs), but it decreased fat mass. The reduction in fat mass was partly due to increased postprandial energy expenditure by stimulation of the sympathetic nervous system (SNS). However, the extracellular signals to ameliorate sarcopenia are unclear. The following three potential extracellular signals to increase muscle mass and function after MCT supplementation are discussed: (1) Activating SNS—the hypothesis for this is based on evidence that a beta2-adrenergic receptor agonist acutely (1–24 h) markedly upregulates isoforms of peroxisomal proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) mRNAs, promotes mitochondrial biogenesis, and chronically (~1 month) induces muscle hypertrophy. (2) An increased concentration of plasma acyl-ghrelin stimulates growth hormone secretion. (3) A nitrogen-sparing effect of ketone bodies, which fuel skeletal muscle, may promote muscle protein synthesis and prevent muscle protein breakdown. This review will help guide clinical trials of using MCTs to treat primary (age-related) sarcopenia. Full article

There is a preliminary record suggesting that β₂-adrenergic agonists may have therapeutic value in Parkinson’s disease; recent studies have proposed a possible role of these agents in suppressing the formation of α-synuclein protein, a component of Lewy bodies. The present study focuses on the importance of the prototypical β₂-adrenergic agonist epinephrine in relation to the incidence of Parkinson’s disease in humans, and its further investigation via synthetic selective β₂-receptor agonists, such as levalbuterol. Levalbuterol exerts significant anti-inflammatory activity, a property that may suppress cytokine-mediated degeneration of dopaminergic neurons and progression of Parkinsonism. In a completely novel finding, epinephrine and certain other adrenergic agents modeled in the Harvard/MIT Broad Institute genomic database, CLUE, demonstrated strong associations with the gene-expression signatures of anti-inflammatory glucocorticoids. This prompted in vivo confirmation in mice engrafted with human peripheral blood mononuclear cells (PBMCs). Upon toxic activation with mononuclear antibodies, levalbuterol inhibited (1) the release of the eosinophil attractant chemokine eotaxin-1, which is implicated in CNS and peripheral inflammatory disorders, (2) elaboration of the tumor-promoting angiogenic factor VEGFa, and (3) release of the pro-inflammatory cytokine IL-13 from activated PBMCs. These observations suggest possible translation to Parkinson’s disease, other neurodegenerative syndromes, and malignancies, via several mechanisms. Full article

The pivotal role of the basolateral amygdala (BLA) in the emotional modulation of hippocampal plasticity and memory consolidation is well-established. Specifically, multiple studies have demonstrated that the activation of the noradrenergic (NA) system within the BLA governs these modulatory effects. However, most current evidence has been obtained by direct infusion of synthetic NA or beta-adrenergic agonists. In the present study, we aimed to investigate the effect of endogenous NA release in the BLA, induced by a natural aversive stimulus (coyote urine), on memory consolidation for a low-arousing, hippocampal-dependent task. Our experiments combined a weak object location task (OLT) version with subsequent mild predator odor exposure (POE). To investigate the role of endogenous NA in the BLA in memory modulation, a subset of the animals (Wistar rats) was treated with the non-selective beta-blocker propranolol at the end of the behavioral procedures. Hippocampal tissue was collected 90 min after drug infusion or after the OLT test, which was performed 24 h later. We used the obtained samples to estimate the levels of phosphorylated CREB (pCREB) and activity-regulated cytoskeleton-associated protein (Arc)—two molecular markers of experience-dependent changes in neuronal activity. The result suggests that POE has the potential to become a valuable behavioral paradigm for studying the interaction between BLA and the hippocampus in memory prioritization and selectivity. Full article

Background and Objectives: Until now, overactive bladder (OAB) with or without urge urinary incontinence (UUI) has been treated mainly in two ways: with behavioral methods and patient education, or using antimuscarinic drugs and/or beta-3 adrenergic receptor agonists. Unfortunately, these drugs may cause side effects in some women or are insufficiently effective, so patients abandon them. Therefore, in this pilot study, radiofrequency was evaluated as a new option in the treatment of OAB and UUI. Materials and Methods: Nineteen patients were enrolled in this pilot study using radiofrequency (RF), where the level of OAB and UUI was assessed using the validated ICIQ-OAB questionnaire. RF was applied four times for 20 min, once a week. Two weeks after treatment, the level of OAB and UUI was reassessed and processed statistically and the treatment effect evaluated. Results: Using the ICIQ-OAB, the severity of OAB and UUI was assessed: 0–3 mild symptoms; 4–7 moderate symptoms; 8–11 severe symptoms; 12–16 very severe symptoms. Before treatment, 10.5% of patients had mild symptoms, 21.1% moderate symptoms, 63.2% severe symptoms and 5.3% very severe symptoms. After treatment, 42.9% had mild symptoms, 50% moderate symptoms and 7% severe OAB and UUI symptoms. All four main symptoms—frequency, nocturia, urgency and incontinence—decreased statistically significantly, with the best results being found in urgency (p = 0.002). Conclusions: Based on this pilot study, RF seems a very promising method in the treatment of OAB and UUI. To extend our initial findings, it is necessary to perform a prospective, randomized and placebo-controlled study in order to obtain reliable results and to determine for how long one set of treatment maintains the results obtained immediately after the end of that treatment. In this way, we may determine how often the treatment needs to be repeated, if necessary, and when. Full article

Improving beef production efficiency, sustainability, and food security is crucial for meeting the growing global demand for beef while minimizing environmental impact, conserving resources, ensuring economic viability, and promoting animal welfare. Beta-adrenergic agonists and dietary protein have been critical factors in beef cattle production. Beta-agonists enhance growth, improve feed efficiency, and influence carcass composition, while dietary protein provides the necessary nutrients for muscle development and overall health. A balanced approach to their use and incorporation into cattle diets can lead to more efficient and sustainable beef production. However, microbiome technologies play an increasingly important role in beef cattle production, particularly by optimizing rumen fermentation, enhancing nutrient utilization, supporting gut health, and enhancing feed efficiency. Therefore, optimizing rumen fermentation, diet, and growth-promoting technologies has the potential to increase energy capture and improve performance. This review addresses the interactions among beta-adrenergic agonists, protein level and source, and the ruminal microbiome. By adopting innovative technologies, sustainable practices, and responsible management strategies, the beef industry can contribute to a more secure and sustainable food future. Continued research and development in this field can lead to innovative solutions that benefit both producers and the environment. Full article

Ischemic stroke is the second-leading cause of death. Hyperglycemia, which is characteristic of diabetes mellitus, contributes to the development of endothelial dysfunction and increases the risk of stroke. Isoxsuprine is an efficient beta-adrenergic agonist that improves blood flow to the ischemic aria and stops the infarct core from growing. However, low bioavailability, a short biological half-life, and first-pass hepatic metabolism reduce the therapeutic efficacy of oral isoxsuprine. Therefore, the authors focused on developing isoxsuprine-loaded liposomes containing ethanol and propylene glycol (ILEP) formulation as nasal drops for the treatment of ischemic stroke in diabetic patients. Different ILEP formulations were optimized using Design Expert software, and the selected formulation was examined in vivo for its anti-stroke effect using a rat model of diabetes and stroke. The optimized ILEP, composed of 15% propylene glycol, 0.16% cholesterol, 10% ethanol, and 3.29% phospholipid, improved the sustainability, permeation, and targeting of isoxsuprine. Furthermore, the in vivo studies verified the improved neurological behavior and decreased dead shrunken neurons and vascular congestion of the rats treated with the optimized ILEP formulation, demonstrating its anti-stroke activity. In conclusion, our study found that treatment with an optimized ILEP formulation prevented the initiation and severity of stroke, especially in diabetic patients. Full article

G protein-coupled receptors in trigeminal ganglion (TG) neurons are often associated with sensory mechanisms, including nociception. We have previously reported the expression of P2Y₁₂ receptors, which are G_i protein-coupled receptors, in TG cells. Activating P2Y₁₂ receptors decreased the intracellular free Ca²⁺ concentration ([Ca²⁺]_i). This indicated that intracellular adenosine 3′,5′-cyclic monophosphate (cAMP) levels can mediate Ca²⁺ signaling in TG cells. Here, we report more extensive-expression patterns of G_s protein-coupled receptors in primary cultured TG neurons isolated from 7-day-old newborn Wistar rats and further examine the roles of these receptors in cAMP signaling using the BacMam sensor in these neurons. To identify TG neurons, we also measured [Ca²⁺]_i using fura-2 in TG cells and measured intracellular cAMP levels. TG neurons were positive for Gα_s protein-coupled receptors, beta-2 adrenergic (β₂), calcitonin gene-related peptide (CGRP), adenosine A_2A (A_2A), dopamine 1 (D1), prostaglandin I₂ (IP), and 5-hydroxytriptamine 4 (5-HT₄) receptor. Application of forskolin (FSK), an activator of adenylyl cyclase, transiently increased intracellular cAMP levels in TG neurons. The application of a phosphodiesterase inhibitor augmented the FSK-elicited intracellular cAMP level increase. These increases were significantly suppressed by the application of SQ22536, an adenylyl cyclase inhibitor, in TG neurons. Application of agonists for β₂, CGRP, A_2A, D1-like, IP, and 5-HT₄ receptors increased intracellular cAMP levels. These increases were SQ22536-sensitive. These results suggested that TG neurons express β₂, CGRP, A_2A, D1, IP, and 5-HT₄ receptors, and the activations of these Gα_s protein-coupled receptors increase intracellular cAMP levels by activating adenylyl cyclase. Full article

The adrenergic beta-2 agonists formoterol and salbutamol are used for the treatment of asthma and COPD but are also misused in sports competitions. Therefore, they are included in WADA regulations. Both drugs are mainly excreted in urine after administration via inhalation. A four-armed, double-blind cross-over clinical trial was conducted involving endurance-trained participants (12 females and 12 males). Inhalation dosages of 36 μg formoterol, 1200 μg salbutamol, a combination of both, or a placebo were administered before exercise. Serum and urine were collected after exercise and 3 and 24 h after administration. Here, we show the successful quantitation of formoterol, salbutamol, and its phase II metabolite salbutamol-4′-O-sulfate in all urine and serum samples using ultra-high performance liquid chromatography–tandem mass spectrometry. In the serum analysis, results of up to 14.2 pg/mL formoterol, 10.0 ng/mL salbutamol, and 21.4 ng/mL salbutamol-4′-O-sulfate (calculated as salbutamol equivalent) were found. In urine, maximum concentrations (after deglucuronidation) were 17.2 ng/mL formoterol, 948.5 ng/mL salbutamol, and 2738.5 ng/mL salbutamol-4′-O-sulfate. Sex-specific differences in serum concentrations as well as in urinary excretion were observed. The results pronounce the importance of the implementation and elucidation of phase II metabolites to quantitation methods in antidoping. Full article

Allosteric regulation is critical for the functioning of G protein-coupled receptors (GPCRs) and their signaling pathways. Endogenous allosteric regulators of GPCRs are simple ions, various biomolecules, and protein components of GPCR signaling (G proteins and β-arrestins). The stability and functional activity of GPCR complexes is also due to multicenter allosteric interactions between protomers. The complexity of allosteric effects caused by numerous regulators differing in structure, availability, and mechanisms of action predetermines the multiplicity and different topology of allosteric sites in GPCRs. These sites can be localized in extracellular loops; inside the transmembrane tunnel and in its upper and lower vestibules; in cytoplasmic loops; and on the outer, membrane-contacting surface of the transmembrane domain. They are involved in the regulation of basal and orthosteric agonist-stimulated receptor activity, biased agonism, GPCR-complex formation, and endocytosis. They are targets for a large number of synthetic allosteric regulators and modulators, including those constructed using molecular docking. The review is devoted to the principles and mechanisms of GPCRs allosteric regulation, the multiplicity of allosteric sites and their topology, and the endogenous and synthetic allosteric regulators, including autoantibodies and pepducins. The allosteric regulation of chemokine receptors, proteinase-activated receptors, thyroid-stimulating and luteinizing hormone receptors, and beta-adrenergic receptors are described in more detail. Full article