Adrenergic Agonists Research Articles

Single-cell transcriptomic analysis reveals dynamic activation of cellular signaling pathways regulating beige adipogenesis.

PDGFRA+ cells have been identified as adipocyte stem cells (ASCs) that differentiate into beige adipocytes in white adipose tissue (WAT) following thermogenic stimuli. To elucidate the molecular heterogeneity of ASCs, we conducted single-cell transcriptomic profiling of PDGFRA+ cells isolated from the inguinal WAT (iWAT) of mice treated with the beta3 adrenergic receptor agonist CL316243. Single-cell RNA-seq revealed nine major clusters, which were categorized into four groups: resting, proliferating, differentiating, and adipogenic factor-expressing cells (AFECs). Trajectory analysis revealed sequential activation of molecular pathways, including the Hedgehog and Notch signaling pathways, during beige adipogenesis. AFECs expressed Dpp4 and did not differentiate into adipocytes in culture or after transplantation. Furthermore, genetic lineage tracing studies indicated that DPP4+ cells did not differentiate into adipocytes in iWAT during CL316243-induced beige adipogenesis. However, high-fat diet feeding led to the recruitment of adipocytes from DPP4+ cells in iWAT. Overall, this study improved our understanding of the dynamic molecular basis of beige adipogenesis and the potential contribution of DPP4+ adipocyte lineages to the pathological expansion of WAT during diet-induced obesity.

Dexmedetomidine preconditioning attenuates ferroptosis in myocardial ischemia-reperfusion injury via α2 adrenergic receptor activation

ObjectiveDexmedetomidine (Dex) is a potent agonist of the α2 adrenergic receptor that has been shown to possess sedative and hypnotic properties. Dex can protect against myocardial ischemia-reperfusion injury (MIRI) by inhibiting ferroptosis. However, these studies were based on Dex post-conditioning, and the role of α2 adrenergic receptors in this process is unclear. In this study, we investigated whether Dex preconditioning can prevent MIRI by attenuating ferroptosis and whether this effect depends on α2 adrenergic receptors in rats. MethodsMale Sprague–Dawley rats were randomly assigned to five groups: sham (saline-treated), I/R (ischemia-exposed), Dex + I/R (Dex pre-treatment), Dex + Yoh + I/R (Dex and yohimbine pre-treatment), and Yoh + I/R (yohimbine pre-treatment). Cardiac function, myocardial infarction, and morphological changes were assessed. Transmission electron microscopy was used to analyze mitochondrial morphology. Ferroptosis-related indicators and lipid peroxidation were measured using western blotting and qRT-PCR. ResultsOur findings indicated that Dex preconditioning improved cardiac function, reduced infarct size and apoptosis, and inhibited ferroptosis in the rat myocardium after MIRI. These effects were associated with the upregulation of Nrf2, SLC7A11, and GPX4 expression, as well as the downregulation of Ferritin, TFR1, ACSL4, COX2, IL-1β, IL-6, and TNF-α expression. Importantly, yohimbine, an α2 adrenergic receptor antagonist, abolished these protective effects. ConclusionThese results suggest that Dex preconditioning can prevent MIRI by attenuating ferroptosis via α2 adrenergic receptor activation and by modulating the Nrf2/SLC7A11/GPX4 pathway.

Critical Management in a Resource-Limited Setting of Amitraz Overdose Case Report

Background: Amitraz poisoning, though rare, poses significant health risks, particularly in developing regions like Africa where its use as an insecticide and acaricide is widespread. Case Presentation: A 24-year-old female in Southwest Uganda was brought to the Emergency Department after intentional ingestion of Amitraz. Initial assessment revealed somnolence, bradycardia, hypotension, and respiratory distress. Despite decontamination, intravenous fluids, and atropine administration, the patient's condition deteriorated, necessitating intubation and transfer to an ICU. Discussion: Amitraz toxicity manifests primarily through central α2 adrenergic receptor agonism, resembling clonidine overdose, with symptoms including hypotension, bradycardia, altered mental status, and respiratory depression. Differentiating Amitraz poisoning from organophosphate toxicity is crucial due to overlapping clinical features but distinct management strategies. Supportive care, including airway management and cardiovascular support, is essential. Conclusion: This case highlights the critical need for awareness and preparedness for Amitraz poisoning in resource-limited settings. Effective supportive care can lead to successful outcomes despite severe initial presentations. Further education and preventive measures are recommended to mitigate risks, especially among vulnerable populations.

Association between the use of prostaglandin analogues and ocular surface disease: a systematic review.

Patients with glaucoma often experience chronic ocular surface diseases, potentially underestimated in frequency and severity. To provide updated estimates of ocular surface diseases linked to prostaglandin analogue antiglaucoma eye medication, a systematic review was conducted. Twenty-seven publications were selected from databases like PubMed, Scopus, and Web of Science, following a search strategy targeting glaucoma and prostaglandins while excluding certain medications '(Glaucoma AND prostaglandins OR 'prostaglandin analogues')('eye drops' OR 'artificial tears' OR 'ocular surface' OR 'dry eye' OR 'dry eye syndrome' OR 'ocular surface disease' OR 'tear film') NOT ('beta blockers' OR 'alpha adrenergic agonists' OR 'carbonic anhydrase inhibitors' OR 'rho-quinase')'. The review revealed a correlation between prostaglandin analogue use and ocular surface damage, assessing parameters such as tear break-up time, Schirmer test value, ocular surface staining, hyperaemia score, and meibomian gland characteristics. Some studies explored switching patients to alternative glaucoma medications, noting varied effects on ocular surface parameters. Comparisons suggested better tolerance and outcomes with preservative-free options over prostaglandins. Additionally, the impact of treatment duration and diquafosol on ocular health, including meibomian gland loss, was examined across different formulations. Although a link between prostaglandin analogues (with or without preservatives) and ocular surface damage was established, inconsistencies in methodologies and assessment across studies were noted. This comprehensive review, spanning a decade of glaucoma research, underscores the need for re-evaluation of treatment strategies in ophthalmology. It stresses the significance of informed decision-making for enhanced glaucoma care, taking into account the observed effects of various medications on eye health.

B-268 Detection of xylazine in fentanyl-positive urine drug screen specimens using a quantitative LCMS/MS method

Abstract Background Fentanyl, a synthetic opioid used clinically for severe pain management, sedation, and as a perioperative analgesic, has been at the forefront of fatal drug-involved overdoses for almost a decade. Xylazine, an α-2 adrenergic receptor agonist, is an increasingly common adulterant in illicitly manufactured fentanyl products and analogs. Given its class, xylazine is non-responsive to naloxone, an opioid receptor antagonist used to reverse opioid overdose. Importantly, the U.S. Drug Enforcement Administration reported xylazine in 23% of seized fentanyl powders and 7% of fentanyl pills; additionally, a recent study by Kariisa et. al. identified an increase of xylazine presence in fatal fentanyl-involved overdoses (2.9% in January 2019 to 10.9% in June 2022) across twenty states.1 Collectively, these trends indicate a need for increased surveillance of xylazine in overdose-presenting patients to inform appropriate clinical responses. In this study, we developed a sensitive LC-MS/MS method for xylazine quantitation and used it to determine xylazine presence in our fentanyl positive patients. Methods An LC-MS/MS method for quantitation of xylazine from urine samples was developed using a Waters Xevo TQ-XS and reversed-phase CORTECS C8 2.7 µm column. MRMs and optimal MS tuning parameters were generated for xylazine and xylazine-d6 via IntelliStart, with transition ions of 221.18→90.04 (Quan) and 221.18→136.31 (Qual) selected for xylazine quantitation against a 227.23→89.98 xylazine-d6 transition as an internal standard. An LC method was developed using water (2 mM Ammonium Acetate; 0.1% Formic Acid v/v) and methanol (2 mM Ammonium Acetate; 0.1% Formic Acid v/v) gradient for a 4-minute runtime. Calibrators were prepared by addition of the pure drug to water, while QCs were prepared using healthy volunteer urine that was confirmed negative in a routine urine drug screen (UDS). Calibrators were value-assigned using a reference laboratory. A simple processing method consisting of the addition of 200 µL methanol containing 25 ng/mL xylazine-d6 to 50 µL of standards, QCs, or urine was used for sample preparation. Remnant fentanyl-positive patient samples (determined by ARK Fentanyl II Immunoassay - Abbott Architect C16000 analyzer) submitted for routine UDS evaluation were collected for xylazine analysis. Results Using custom xylazine standards, the method yielded a linear range from 2 ng/mL to 500 ng/mL with an average R2 of 0.9995 across runs (n = 12). The LLoQ for this assay was 2 ng/mL with a CV of 18.1%. The intra-assay CVs were < 5.0% and inter-assay CVs were < 15.0%. Of preliminary patient samples tested (n = 25), xylazine was detected in 32% of fentanyl-positive samples, ranging in concentration from 2.8 ng/mL to 192.8 ng/mL with an average of 64.8 ng/mL. Conclusions Here we report a simple LC-MS/MS method for quantitation of xylazine in remnant fentanyl-positive UDS specimens by LC-MS/MS. Preliminary testing revealed a xylazine positivity rate of 32% in fentanyl-positive patients. Uncomplicated sample work-up makes this method applicable to xylazine surveillance in all UDS-positive patient samples in high-throughput clinical laboratories. Reference: 1. Kariisa M, et. al. “Illicitly Manufactured Fentanyl-Involved Overdose Deaths with Detected Xylazine.” MMWR Morb Mortal Wkly Rep 2023;72:721-727.

Pharmacological Treatment of Tourette Disorder in Children.

Background: Tourette disorder (TD) is a neurodevelopmental disorder characterized by childhood onset of tics lasting more than one year, with multiple motor tics and at least one phonic tic at some point during the course of the symptoms. Treatment of tics may include psychoeducation, non-pharmacologic treatment, or pharmacologic treatment. We review pharmacologic treatment here. Methods: We performed a literature review on pharmacologic treatments for TD. Results: There is no current evidence to suggest that medications impact the prognosis of tic disorders, so current clinical guidelines recommend reassurance of the patient and family and monitoring if there is no change in function or quality of life due to tics. If treatment is indicated, it must be chosen based on the needs of each individual patient. Comprehensive behavioral intervention for tics (CBIT) is considered first-line management for most individuals with bothersome tics, especially if they are mild to moderate in severity. Pharmacotherapy should be considered when tics are impairing daily functioning, causing social problems, accompanied by other neuropsychiatric symptoms, or when the patient is not likely to benefit from CBIT. Current recommended pharmacotherapy options include alpha-2 adrenergic agonists, dopamine modulators, GABAergic medications, dopamine depleters, and botulinum toxin injections. Additionally, there are other novel medications that are being studied in ongoing clinical trials. Conclusions: This review summarizes available pharmacotherapy options for TD in children. It provides an overview of new medications and offers guidance to physicians when selecting appropriate treatments. If medications are indicated for tic management, treatment should be chosen based on the needs of the individual patient.

The association between antiglaucomatous agents and Alzheimer's disease.

To estimate the risk of Alzheimer's disease (AD) associated with long-term use of topical glaucoma medications among middle-aged and older glaucoma patients, and compare the AD risk among various glaucoma subtypes. This nationwide population-based cohort study utilized insurance claims data from Taiwan's National Health Insurance Research Database between 2008 and 2019. Participants were adults aged 45 years or older either with a diagnosis of glaucoma or without. Those with glaucoma must have received single antiglaucomatous medication (including α2-adrenergic agonists, cholinergic agonists, beta-blockers, prostaglandin analogs, and pilocarpine) for over 90 days. Those with pre-existing AD diagnoses prior to the index date were excluded. A total of 202,000 participants were included in the study, with 101,000 in each group (glaucoma and control groups). Glaucoma patients on topical alpha-2 adrenergic agonist monotherapy exhibited a significantly higher AD risk (aHR 1.15, 95% CI = 1.01-1.31) compared to those on beta-blockers. Glaucoma was further categorized into primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), primary angle-closure glaucoma (PACG), and unspecified glaucoma. Irrespective of the type of glaucoma, individuals with glaucoma had a significantly higher risk of AD compared to those without glaucoma (POAG: aHR 1.23, 95% CI = 1.08-1.40; NTG: aHR 1.49, 95% CI = 1.19-1.85; PACG: aHR 1.35, 95% CI = 1.19-1.52; unspecified glaucoma: aHR 1.36, 95% CI = 1.23-1.50). Topical alpha-2 adrenergic agonists might pose increased AD risk in individuals with glaucoma compared to beta-blockers. Accordingly, their utilization should be undertaken judiciously, especially in middle-aged and older populations. Our findings also indicate glaucoma may increase the risk of AD regardless of glaucoma subtype.

The Effect of Trimetazidine Combined with Cardiac Rehabilitation on the Prognosis of Patients with Acute Myocardial Infarction

Objective: To investigate the effects of Trimetazidine (TMZ) combined with Cardiac Rehabilitation (CR) on acute myocardial infarction (AMI). A Acute Myocardial Infarction (AMI) patients who underwent PCI, the effects of ventricular remodeling and quality of life at different times after PCI; to observe the changes in the expression of Nod-Like Receptor Protein 3 (NLRP3) in peripheral blood mononuclear cells at different times after the onset of AMI and the effects of TMZ combined with CR therapy on it. Methods: The study population was selected from 89 AMI patients admitted to the Second Hospital of Dalian Medical University from October 2018 to January 2020. All of them underwent PCI in emergency or within 2 days of admission, and they were all treated with double antibiotics, heparin and statins, and β-receptor antagonists or CCB or RAS system antagonists according to the patients' blood pressure and heart rate. The patients were divided into a control group and a rehabilitation group according to their willingness and adherence to rehabilitation. The control group consisted of 44 patients (n=44), who were treated only with the above treatments and no other treatments. The rehabilitation group consisted of 45 patients (n=45) who were treated with TMZ and CR in combination with the above treatments. In the rehabilitation group, the cardiac rehabilitation program was initiated as appropriate from day 2 after PCI, and trimetazidine hydrochloride treatment (35 mg bid po) was given on day 7 after PCI for a total of 1 year (52±2 weeks). Blood was collected in the morning of the 2nd day of admission for routine blood tests, cTnI, lipids, blood glucose, liver and kidney function, and glycosylated hemoglobin. Cardiac ultrasound was performed at weeks 1, 4, 12, and 52±2, and left ventricular end-diastolic diameter (LVEDd) and left ventricular ejection fraction (LVEF) were measured. The Quality of Life Scale (SF-12) and Generalized Anxiety Disorder Scale (GAD-7) were assessed at week 1 and week 52±2. Cardiopulmonary exercise test was performed at week 1 and week 52±2 of onset, and maximum kilogram oxygen uptake (peakVO2/kg), kilogram oxygen uptake at anaerobic threshold (VO2/kg@AT), and metabolic equivalents at anaerobic threshold (Mets@AT) were recorded. The expression of NLRP3 in peripheral blood mononuclear cells of patients at 24-36 hours of onset, week 1, week 4, week 12 and week 52±2 was detected. All the above data were analyzed by SPSS 24.0 software. Results: At 1 year of onset, LVEDd was less in the rehabilitation group than in the control group. At weeks 4 and 12 of onset, LVEF was higher in the rehabilitation group than in the control group. At 1 year after the onset of the disease, the quality of life and anxiety and depression status of the rehabilitation group were significantly improved, the SF-12 score was higher than that of the control group, and the GAD-7 score was lower than that of the control group. And the cardiopulmonary exercise experiment indexes of the two groups were compared, and the peakVO2/kg, VO2/kg@AT and Mets@AT of the rehabilitation group were significantly higher than those of the control group. During the 1-year follow-up, peripheral blood mononuclear cell NLRP3 levels tended to decrease in both groups and were at their highest values at 24-36 hours after onset. At weeks 4 and 12, peripheral blood mononuclear cell NLRP3 levels were significantly lower in the rehabilitation group than in the control group. Conclusion: TMZ combined with CR therapy showed significant improvement in ventricular remodeling, exercise tolerance, and quality of life in patients with AMI, and it was most effective and beneficial to patients at 1 year after PCI. TMZ combined with CR therapy significantly reduced peripheral blood mononuclear cell NLRP3 levels in AMI patients, and the effect was most pronounced at 3 months after PCI.

Advancing Glaucoma Therapy by Exploring the Efficacy and Potential of Brimonidine Niosomal Gel

Glaucoma is a leading cause of permanent vision loss worldwide and is characterised by progressive optic neuropathy with elevated intraocular pressure (IOP) as a major risk factor. Although successful, the current therapeutic strategies are often severely limited by their need for chronic dosing, systemic side effects and poor patient compliance. Brimonidine, an alpha-2 adrenergic receptor agonist which acts selectively, has been beneficial through its IOP-lowering effects by diminishing aqueous humor production and improving uveoscleral outflow. A novel medication delivery technology to enhance ocular bioavailability and extended drug release is brimonidine, formulated as a niosomal gel. The aim of this study is to highlight its clinical efficacy, formulation strategies and mechanism of action that significantly improved glaucoma therapy. Key studies illuminate its potential benefits in reducing dosing frequency, avoiding side effects and increasing patient compliance. Additional study and optimization required to scale-up manufacturing or ensure long-term stability. Possible future directions: combination medications and delivery systems personalized medicine possible future directions in the treatment of glaucoma might include combination medicines and personalized medicine techniques tailored to patient-specific needs. Brimonidine niosomal gel may be a new approach for glaucoma management and it can change the concept of intraocular drug delivery in the future.

Cognitive and Histopathological Alterations in Rat Models of Early- and Late-Phase Memory Dysfunction: Effects of Sigma-1 Receptor Activation.

Sigma-1 receptors are highly expressed in brain areas related to cognitive function and are a promising target for anti-amnesic treatments. We previously showed that activation of sigma-1 receptors by the selective agonist compound methyl(1 R,2 S/1 S,2 R)-2-[4-hydroxy-4-phenylpiperidin-1-yl)methyl]-1-(4-methylphenyl) cyclopropane carboxylate [(±)-PPCC] promotes a remarkable recovery in rat models of memory loss associated to cholinergic dysfunction. In this study, we sought to assess the role of (±)-PPCC on working memory deficits caused by noradrenergic depletion. Animals with a mild or severe working memory deficits associated to varying degrees of noradrenergic neuronal depletion were treated with the sigma-1 agonist just prior to the beginning of each behavioral testing session. While (±)-PPCC alone at a dose of 1 mg/kg/day failed to affect working memory in lesioned animals, its association with the α2 adrenergic receptor agonist clonidine, completely blocked noradrenaline release, significantly improving rat performance. This effect, distinct from noradrenaline activity, is likely to result from a direct action of the (±)-PPCC compound onto sigma-1 receptors, as pre-treatment with the selective sigma-1 receptor antagonist BD-1047 reversed the improved working memory performance. Despite such clear functional effects, the treatment did not affect noradrenergic neuron survival or terminal fiber proliferation. Future studies are thus necessary to address the effects of long-lasting (±)-PPCC treatment, with or without clonidine, on cognitive abilities and Alzheimer's disease-like histopathology. Considering the already established involvement of sigma-1 receptors in endogenous cell plasticity mechanisms, their activation by selective agonist compounds holds promises as possibly positive contributor to disease-modifying events in neurodegenerative diseases.

Comparison of Efficacy of Intravenous Tramadol and Intravenous Dexmedetomidine on Post-Spinal Anesthesia Shivering in Caesarean Section

Background: Post-aesthetic shivering is a common complication after neuraxial anaesthesia, often managed with agents like tramadol and meperidine, which are associated with adverse effects such as nausea and vomiting. Dexmedetomidine, a centrally acting alpha-2 adrenergic agonist, may offer a safer alternative.Objective: To compare the efficacy of intravenous tramadol and intravenous dexmedetomidine in controlling post-spinal anaesthesia shivering in obstetric patients undergoing caesarean sections.Methods: This quasi-experimental study was conducted from 20 February to 20 August 2024, involving 120 patients undergoing elective cesarean sections who developed post-spinal shivering. Patients were randomly assigned to receive either intravenous dexmedetomidine (0.5 mcg/kg) or tramadol (0.5 mg/kg). Outcomes measured included time to shivering cessation, recurrence, and adverse effects, analysed using independent sample t-tests and Chi-square tests with significance set at p ≤ 0.05.Results: The time to cessation of shivering was significantly shorter with dexmedetomidine (172.12 ± 14.26 seconds) compared to tramadol (278.06 ± 23.17 seconds, p < 0.001). Shivering recurrence was 5% in the dexmedetomidine group versus 16.66% in the tramadol group (p = 0.03).Conclusion: Dexmedetomidine demonstrated superior efficacy in controlling post-spinal anaesthesia shivering with fewer adverse effects compared to tramadol, making it a preferred option in obstetric settings.

Abstract P453: Dissecting tunica responsibility in arterial stress relaxation: Smooth muscle need not apply

Perivascular adipose tissue (PVAT) is being recognized as an important arterial tunica. Stress relaxation, a gradual reduction in stress over time while under a constant strain, is considered a property of smooth muscle (ex. intestine, uterus, bladder). While aortic PVAT (aPVAT) contains a microvasculature, it does not contain organized smooth muscle and isolated PVAT stress relaxes to a greater extent than the vessel itself. This raised the idea that other tunicas lacking smooth muscle may also stress relax. Here we hypothesize that appropriately oriented and functional smooth muscle was not necessary for stress relaxation to occur. To test this, we used histochemical staining and isometric contractility of thoracic aorta from the male Dahl salt-sensitive (SS) rat. Some rings of aorta were separated into adventitia (no muscle), media (muscle), and PVAT (no muscle), and responses of these isolates compared to the intact aortic ring (muscle + integration of tunicas). Masson Trichrome (MT) and Verhoeff Van Gieson (VVG) staining validated the dissection of the different tunicas with minimal contamination of cells from other tunicas. Stress relaxation was measured after increasing, cumulative amounts of passive tension (6 grams total) was applied in the presence or absence of Ca 2+ , essential for smooth muscle contraction. Each step was followed by challenge with a maximum concentration of the a 1 adrenergic agonist phenylephrine (PE, 10 -5 M). Stress relaxation occurred in all tunicas at each passive tension, whether or not Ca 2+ was present (figures). In fact, loss of Ca 2+ improved stress relaxation in adventitia and PVAT. Importantly, in the presence of Ca 2+ , PE contraction was observed at each passive tension in tissues containing smooth muscle: media (min, 250 mg PT: 26.67 +/- 8.51 mg; max, 6000 mg PT: 589.59 +/- 114.53 mg) and aorta + PVAT (min, 250 mg PT: 562.61 +/- 238.45 mg; max, 6000 mg PT: 1322.91 +/- 352.73mg). Little to no measurable contraction was recorded in the adventitia and aPVAT. There was little to no measurable contraction in tunicas in the absence of Ca 2+ . Taken together, these data suggest that all tunicas of the rat thoracic aorta stress relax and can do so without the presence of organized smooth muscle. Of all tunicas, PVAT demonstrated the greatest ability to stress relax. Collectively, these findings force reconsideration of individual responsibilities of arterial tunicas, all of which participate in the (dys)function of an artery.

Ex Vivo Irritation Evaluation of a Novel Brimonidine Nanoemulsion Using the Hen's Egg Test on Chorioallantoic Membrane (HET-CAM).

The hen's egg test on chorioallantoic membrane (HET-CAM) assay is a cost-effective and well-validated, non-animal-based ex vivo method for evaluating the irritant potential and eye toxicity of substances. A colloidal dispersion of a surfactant and a cosurfactant with a nanosize range is called a nanoemulsion (NE), which is formed by mixing immiscible liquids and stabilized by surfactants. Patients with glaucoma are commonly prescribed Brimonidine (BR), an alpha-2 adrenergic agonist, to lower their intraocular pressure. In this study, surfactant-cosurfactant blends were prepared by mixing Tween 80 (surfactant) and propylene glycol (cosurfactant) in a 4:1(v/v) ratio. Triacetin served as the oil phase, while deionized water was used as the aqueous phase. Using the drop method, a range of NE formulations (F1, F2, F3, FB1, FB2, and FB3) were developed and subsequently evaluated for their potential to irritate, and then the results were compared to those of a commercially available BR eye drop formulation. According to the average cumulative HET-CAM test scores (IS), from excipients, propylene glycol caused moderate irritation by causing slight damage to blood vessels. The formulations FB1 and F1 were found to have the highest level of irritation among other formulations in the investigation, recording 1.05 ±0.07 and 1.2 ±0.10, respectively. All other NE formulations exhibited non-irritating potential, as confirmed by the HET-CAM test, and were comparable to the marketed BR eye drop formulation. The NE formulations created for BR were determined to be safe and non-irritating. The findings indicate that the prepared NE could be a beneficial solution for addressing problems with conventional eye drops and delivering BR effectively to the eyes.

Evidence-Based Clinical Guidelines for Chronic Diarrhea 2023.

The Japan Gastroenterological Association (JGA) published the first version of clinical guidelines for chronic diarrhea 2023. These guidelines describe the definition, classification, diagnostic criteria, diagnostic testing methods, epidemiology, pathophysiology, and treatment of chronic diarrhea, and provide flowcharts for the diagnosis and treatment of chronic diarrhea based on the latest evidence. Treatment for chronic diarrhea begins by distinguishing secondary chronic constipation with a clear etiology, such as drug-induced diarrhea, food-induced diarrhea, systemic disease-associated diarrhea, infection-associated diarrhea, organic disease-associated diarrhea, and bile acid diarrhea. The first line of treatment for chronic diarrhea in the narrow sense, defined in these guidelines as functional diarrhea in routine medical care, is lifestyle modification and dietary therapy. The first medicines to be considered for oral treatment are probiotics for regulating the gut microbiome and antidiarrheals. Other medications, such as 5HT3 receptor antagonists, anticholinergics, Kampo medicine, psychotherapy, antibiotics, bulking agents, adrenergic agonists, and somatostatin analogues, lack sufficient evidence for their use, highlighting a challenge for future research. This Clinical Guidelines for Chronic Diarrhea 2023, which provides the best clinical strategies for treating chronic diarrhea in Japan, will also be useful for medical treatment worldwide.

Unveiling the protective potential of mirabegron against thioacetamide-induced hepatic encephalopathy in rats: Insights into cAMP/PPAR-γ/p-ERK1/2/p S536 NF-κB p 65 and p-CREB/BDNF/TrkB in parallel with oxidative and apoptotic trajectories

Hepatic encephalopathy (HE) is one of the most prevalent and severe hepatic and brain disorders in which escalation of the oxidative, inflammatory and apoptotic trajectories pathologically connects acute liver injury with neurological impairment. Mirabegron (Mira) is a beta3 adrenergic receptor agonist with proven antioxidant and anti-inflammatory activities. The current research pointed to exploring Mira’s hepato-and neuroprotective impacts against thioacetamide (TAA)-induced HE in rats. Rats were distributed into three experimental groups: the normal control group, the TAA group, received TAA (200 mg/kg/day for three consecutive days) and the Mira-treated group received Mira (10 mg/kg/day; oral gavage) for 15 consecutive days and intoxicated with TAA from the 13th to the 15th day of the experimental period. Mira counteracted hyperammonemia, enhanced rats’ locomotor capability and motor coordination. It attenuated hepatic/neurological injuries by its antioxidant, anti-apoptotic as well as anti-inflammatory potentials. Mira predominantly targeted cyclic adenosine monophosphate (cAMP)/phosphorylated extracellular signal-regulated kinase (p-Erk1/2)/peroxisome proliferator-activated receptor gamma (PPARγ) dependent pathways via downregulation of p S536-nuclear factor kappa B p65 (p S536 NF-κB p 65)/tumor necrosis alpha (TNF-α) axis. Meanwhile, it attenuated nuclear factor erythroid 2-related factor (Nrf2) depletion in parallel with restoring of the neuroprotective defensive pathway by upregulation of cerebral cAMP/PPAR-γ/p-ERK1/2 and p-CREB/BDNF/TrkB besides reduction of GFAP immunoreactivity. Mira showed anti-apoptotic activity through inhibition of Bax immunoreactivity and elevation of Bcl2. To summarize, Mira exhibited a hepato-and neuroprotective effect against TAA-induced HE in rats via shielding antioxidant defense and mitigation of the pathological inflammatory and apoptotic axis besides upregulation of neuroprotective signaling pathways.

Are Alpha-2 Adrenergic Agonists Being Used in Infants?

Purpose: To identify and quantify adverse events (AEs) associated with alpha-2 adrenergic agonists prescribed for the treatment of glaucoma in infants. Methods: We queried the Federal Adverse Event Reporting System (FAERS) from 2004-2023Q1 for AE reports related to brimonidine use in patients aged 12 months or younger. We then conducted a disproportionality analysis using data mining algorithms, including the reporting odds ratio, proportional reporting ratio, empirical bayes geometric mean, and information component to identify significant symptoms. Results: We identified 35 unique AE reports associated with brimonidine. Of these, 27 cases involved hospitalization, 13 cases involved life-threatening complications, 18 cases reported other complications, and 1 case involved a congenital anomaly. The most commonly reported AE was hypotonia, occurring in 20 cases. This was followed by other systemic symptoms, including hypothermia, depressed level of consciousness, lethargy, general toxicity, and pallor, among others. All symptoms were found to be significant in the disproportionality analysis. Notably, most cases were not known to involve an ophthalmic route of exposure. Conclusions: The use of alpha-2 adrenergic agonists in infants aged 1 year or younger has been associated with various systemic AEs, including hypotension, respiratory depression, and central nervous system depression. Ophthalmologists should be aware of these potential risks. Further, more rigorous warnings should be in place to prevent unintentional exposure of infants to brimonidine.

Spectroscopic investigation of drug potential towards neuronal firing and analysis of molecular docking on (N-(diaminomethylidene)-2-(2,6-dichlorophenyl) acetamide) using DFT theoretical data evidence

Guanfacine is an alpha-A2 adrenergic receptor agonist used for the treatment of attention deficit hyperactivity disorder. Guanfacine also known as (N-(diaminomethylidene)-2-(2,6-dichlorophenyl) acetamide) and in this work it was investigated by interpreting physico-chemical, structural and biological properties using FT-Raman, FT-IR, NMR and UV–Visible spectral datum along with computational results. The optimized geometry of the molecular structure was sketched and deviation of parametric values has been interpreted. The vibrational analysis along with vibrational assignments was carried out to understand the impact of nitro, methylidine, chloro effects on acetamide base molecule to change in drug mechanism. The molecular charge population delocalization on par with substituent was analyzed and purpose of electron cloud accumulation on different entities was justified. The drug likeness score was calculated and bioavailability was tested. The enzymatic target investigation was made on theoretical results of HyperChem. The vibrational characteristics of the compound were evaluated and the chemical-patrician energy of bonds and their influences on drug property change were tested. Chemical reaction path mechanism was mapped to find the root cause of chemical kinetics to enable antimicrobial activity on the heart of Guanfacine molecule. The doubly degenerate interaction orbitals were viewed and the transitions assigned to facilitate the drug activity were studied. The toxicity profile was evaluated by opting enantiomer and validated by simulating VCD spectrograph. The Guanfacine docked into the active site of 5R7Y and 6MOJ indicates conceal antiviral activity, consistent with results from the PASS database. Using the autodock program, docking molecules (ligand-proteins) were simulated.

Anchored PKA synchronizes adrenergic phosphoregulation of cardiac Cav1.2 channels

Adrenergic modulation of voltage gated Ca2+ currents is a context specific process. In the heart Cav1.2 channels initiate excitation-contraction coupling. This requires PKA phosphorylation of the small GTPase Rad (Ras associated with diabetes) and involves direct phosphorylation of the Cav1.2 α1 subunit at Ser1700. A contributing factor is the proximity of PKA to the channel through association with A-kinase anchoring proteins (AKAPs). Disruption of PKA anchoring by the disruptor peptide AKAP-IS prevents upregulation of Cav1.2 currents in tsA-201cells. Biochemical analyses demonstrate that Rad does not function as an AKAP. Electrophysiological recording shows that channel mutants lacking phosphorylation sites (Cav1.2 STAA) lose responsivity to the second messenger cAMP. Measurements in cardiomyocytes isolated from Rad-/- mice show that adrenergic activation of Cav1.2 is attenuated but not completely abolished. Whole animal electrocardiography studies reveal that cardiac selective Rad KO mice exhibited higher baseline left ventricular ejection fraction, greater fractional shortening, and increased heart rate as compared to control animals. Yet, each parameter of cardiac function was slightly elevated when Rad-/- mice were treated with the adrenergic agonist isoproterenol. Thus, phosphorylation of Cav1.2 and dissociation of phospho-Rad from the channel are local cAMP responsive events that act in concert to enhance L-type calcium currents. This convergence of local PKA regulatory events at the cardiac L-type calcium channel may permit maximal β-adrenergic influence on the fight-or-flight response.

Methylphenidate Reversal of Dexmedetomidine-Induced Versus Ketamine-Induced Sedation in Rats.

Dexmedetomidine and ketamine have long elimination half-lives in humans and have no clinically approved reversal agents. Methylphenidate enhances dopaminergic and noradrenergic neurotransmission by inhibiting reuptake transporters for these arousal-promoting neurotransmitters. Previous studies in rats demonstrated that intravenous methylphenidate induces emergence from isoflurane and propofol general anesthesia. These 2 anesthetics are thought to act primarily through enhancement of inhibitory Gamma-aminobutyric acid type A (GABAA) receptors. In this study, we tested the behavioral and neurophysiological effects of methylphenidate in rats after low and high doses of dexmedetomidine (an alpha-2 adrenergic receptor agonist) and ketamine (an N-methyl-D-aspartate [NMDA] receptor antagonist) that induce sedation and unconsciousness, respectively. All experiments used adult male and female Sprague-Dawley rats (n = 32 total) and all drugs were administered intravenously in a crossover, blinded experimental design. Locomotion after sedating doses of dexmedetomidine (10 µg/kg) or ketamine (10 mg/kg) with and without methylphenidate (5 mg/kg) was tested using the open field test (n = 16). Recovery of righting reflex after either high-dose dexmedetomidine (50 µg/kg) or high-dose ketamine (50 mg/kg) with and without methylphenidate (1-5 mg/kg) was assessed in a second cohort of rats (n = 8). Finally, in a third cohort of rats (n = 8), frontal electroencephalography (EEG) was recorded for spectral analysis under both low and high doses of dexmedetomidine and ketamine with and without methylphenidate. Low-dose dexmedetomidine reduced locomotion by 94% in rats. Methylphenidate restored locomotion after low-dose dexmedetomidine (rank difference = 88.5, 95% confidence interval [CI], 70.8-106) and the effect was blocked by coadministration with a dopamine D1 receptor antagonist (rank difference = 86.2, 95% CI, 68.6-104). Low-dose ketamine transiently attenuated mobility by 58% and was not improved with methylphenidate. Methylphenidate did not affect the return of righting reflex latency in rats after high-dose dexmedetomidine nor ketamine. Frontal EEG analysis revealed that methylphenidate reversed spectral changes induced by low-dose dexmedetomidine (F [8,87] = 3.27, P = .003) but produced only transient changes after high-dose dexmedetomidine. Methylphenidate did not induce spectral changes in the EEG after low- or high-dose ketamine. Methylphenidate reversed behavioral and neurophysiological correlates of sedation, but not unconsciousness, induced by dexmedetomidine. In contrast, methylphenidate did not affect sedation, unconsciousness, nor EEG signatures in rats after ketamine. These findings suggest that methylphenidate may be efficacious to reverse dexmedetomidine sedation in humans.

Preclinical Female Model of Urogenital Dysfunction and Pathophysiological Changes After Pelvic Radiation Therapy.

Introduction Radiation therapy (RT) is the gold standard for many pelvic cancers and improves overall patient survival. However, pelvic RT is associated with increased sexual dysfunction and urinary incontinence. Although the side effects of pelvic RT are well-documented, the pathological mechanisms leading to pelvic organ dysfunction are unknown, and a preclinical model has not been established. This study characterized the impact of pelvic RT at early and late timepoints on female rat bladder, vaginal, and urethral physiology and morphology. Methods Adult female Sprague-Dawley rats were divided into three groups (n = 8/group): (I) Sham, (II) four weeks RT (4wk RT), and (III) nine weeks RT (9wk RT). The RT groups received a single dose of 20 Gy external beam radiation, and experiments were conducted at 4wk and 9wk post-RT. Nerve-mediated vaginal blood flow was measured via laser Doppler. Tissue bath studies assessed vaginal contractility to electric field stimulation (EFS), adrenergic and cholinergic agonists, and relaxation to a nitric oxide donor. Bladder and urethral sphincters were evaluated for cholinergic, caffeine, and EFS-mediated contractility. Quantitative polymerase chain reaction (qPCR) measured gene expression of markers of oxidative stress. Vaginal, bladder, and urethral fibrosis were assessed with Masson's trichrome staining. Results At 4wk post-RT, total vaginal blood flow decreased, and at 9wk post-RT, returned to baseline levels. At 9wk post-RT, vaginal neurogenic and adrenergic-mediated contractile responses increased significantly. Vaginal epithelial thickness decreased post-RT and correlated with an acute rise in vaginal inflammatory gene expression. At 4wk post-RT, bladder neurogenic contractions decreased and remained lowered. Internal urethral contractions increased at 4wk post-RT and returned to Sham levels after 9wk post-RT. Pelvic RT increased external urethral neurogenic contractions, which remained elevated. Conclusion This novel preclinical model provides valuable insights into the temporal pathophysiology of pelvic RT-induced sexual and urinary dysfunction. The establishment of this model is crucial for understanding the underlying mechanisms involved in RT-induced pelvic injury. A reliable, clinically relevant model will allow for the testing of therapeutic strategies to prevent adverse effects with RT in pelvic cancer survivors.