Search Results (254)

In left ventricular hypertrophy (LVH), the combined external administration of hydrogen sulfide (H₂S) and nitric oxide (NO) has been shown to reverse LVH by activating the endothelial nitric oxide synthase pathway (eNOS/NO), independent of the cystathionine γ-lyase (CSE/H₂S) pathway. Individually, both H₂S and NO have also been reported to significantly improve RCBP, restore renal excretory performance, and enhance α-adrenergic receptor responsiveness in rats. The induction of LVH was performed over a period of two weeks using drinking water with caffeine and isoprenaline. Five weeks later, the rats were fed with L-arginine (1.25 g/L) as a nitrogen oxide donor. Vascular reactions to methoxamine, phenylephrine, and noradrenaline were assessed in presences and absence of 5-methylurapidil (5-MeU), BMY7378, and chloroethylclonidine (CeC) and α1-adrenoceptor antagonists. In both the Control WKY and LVH-WKY groups, combined H₂S+NO therapy significantly (p < 0.05) upregulated the renal mRNA of CSE and eNOS when compared with untreated LVH rats. The treatment also markedly increased RCBP in LVH-H₂S+NO rats relative to LVH controls. Furthermore, H₂S+NO administration enhanced the activity of α_1A, α_1B, and α_1D adrenergic receptors in mediating renal vasoconstriction. Even under receptor blockade with high doses (HDs) of 5-MeU, CeC, and BMY 7378, renal vasoconstriction responses to adrenergic agonists like NA, PE, and ME in the LVH-H₂S+NO group remained comparable to those observed in the counterpart Control-H₂S+NO group. The findings of current study suggest that simultaneous exogenous administration of H₂S and NO donors improve renal cortical blood flow, support renal function, and augment α_1A, α_1B, and α_1D adrenergic receptor responsiveness to adrenergic agonists like NA, PE, and ME in LVH rats. This effect appears to rely primarily on the eNOS/NO pathway, with partial contribution from the CSE/H₂S pathway. Full article

Background: Low temperature stress is a major environmental challenge affecting the growth, metabolism, and survival of many aquaculture species, including Nile tilapia (Oreochromis niloticus). Understanding the molecular mechanisms underlying cold tolerance is therefore essential for improving fish resilience and aquaculture sustainability. Methods: In the present study, an acute cold stress model of Nile tilapia (Oreochromis niloticus) was established and it was found that uncoupling protein 1 (UCP1) was involved in the acute cold stress process of tilapia. Results: The upregulation of UCP1 in the liver under cold stimulation was regulated by stress hormones such as cortisol and adrenaline. UCP1 has a short half-life and is degraded by proteasomes. In tilapia primary hepatocytes, the addition of adrenergic receptor agonists resulted in mitochondrial membrane potential decreasing, while UCP1 siRNA transfection inhibited mitochondrial membrane potential. Biochemical characteristics indicate that UCP1 is a channel protein that mediates proton leakage. In addition, feeding and intraperitoneal injection of mitochondrial uncoupling agent BAM15 can alleviate the low-temperature stress of tilapia. Conclusions: UCP1 helps maintain the metabolic homeostasis of tilapia under acute cold stimulation and provides new insights into the mechanisms of cold resistance as well as potential treatment strategies in fish. Full article

Uveal melanoma (UM) is the most common primary intraocular tumor in adults. Because of its high potential for spreading and its limited response to treatment, UM remains a clinical challenge. Previous studies suggest that clinical adrenergic receptor (AR) antagonists might be effective in the treatment of UM. This study reports the antitumor activity of α-blocker in UM spheroids generated from α_1A- and α_2A-AR-positive UM cell lines. These cell lines were derived from primary tumors or hepatic metastases and differed in their genetic risk status for metastasis. Drug screening with UM spheroids revealed that prazosin and doxazosin dose-dependently reduced viability, whereas terazosin, alfuzosin, silodosin, tamsulosin, and phenoxybenzamine were found to be inefficient. Prazosin induced apoptosis, resulting in the disintegration of UM spheroid morphology and growth inhibition. Additionally, prazosin prevented UM spheroid cell outgrowth and long-term survival, indicating potential for tumor control. Like the selective α_1A-AR antagonist RS17053, prazosin inhibited the formation and growth of UM spheroids stimulated by the α_1-agonist phenylephrine. This suggests a tumor-preventive effect through the blockade of α_1A-AR. The present study highlights the responses of UM spheroids to α-AR antagonists and demonstrates that prazosin, doxazosin, or RS17053 may be a treatment option for preventing UM tumor recurrence or metastasis. Full article

Background: Fixed-dose combination medications (FDCs) are recognized methods of increasing adherence to polytherapy in chronic diseases. However, the role of FDCs in patients with benign prostatic hyperplasia (BPH) associated with lower urinary tract symptoms (LUTS) remains uncertain. We designed this study to assess persistence, adherence, and patient satisfaction with FDCs recently introduced to the Polish pharmaceutical market, which contain tamsulosin (an α1-adrenergic receptor antagonist) in combination with solifenacin (a muscarinic receptor antagonist) or dutasteride (a 5-α reductase inhibitor). Methods: The analysis included 50,435 men (67.8 ± 8.8 years old) managed by urologists for BPH-associated LUTS, who had been on combination therapies for at least 3 months. Two study visits, with an interval of 2.1 ± 1.4 months, were conducted between February and December 2024. Results: Single-component drugs (83.1%) were more common forms of therapy compared to FDCs (16.9%). ARAs (α1-adrenergic receptor antagonists) with 5-α reductase inhibitors comprised 70.2%, while ARAs with muscarinic receptor antagonists or β3-adrenergic agonists comprised 29.5%. Persistence with therapy across two visits was 82.0% for single-component drugs and 93.6% for FDCs (p < 0.001); OR = 1.31 (95% CI: 1.02–1.63). Similarly, adherence was better in patients treated with FDCs (96.6% vs. 91.0% at visit 1, p < 0.001; 99.3% vs. 97.9% at visit 2, p < 0.05). Patients prescribed FDCs were satisfied with therapy more often than those prescribed single-component drugs (62.6% and 76.8% vs. 50.6% and 67.5% at visits 1 and 2, respectively; p < 0.001). Conclusions: 1. Combination therapies are still more commonly administered as separate tablets than FDCs in patients with BPH-associated LUTS. 2. The use of FDCs increases short-term satisfaction and persistence with therapy, with a mild effect on adherence. Full article

Objective: This study was conducted to evaluate the potential radioprotective and therapeutic effects of dexmedetomidine (DEX), a selective α2-adrenergic receptor (α2AR) agonist, against ionizing X-ray-induced small intestinal injury in a dose-dependent manner. Methods: Male Sprague Dawley rats were randomly categorized into four groups. These groups were the Control, Ionizing Radiation (IR, 8 Gy X-ray), IR+DEX 100 µg/kg, and IR+DEX 200 µg/kg. DEX was administered intraperitoneally to the treatment groups 30 min before radiation exposure. All groups were sacrificed 24 h following irradiation. Firstly, the small intestinal tissues were evaluated histopathologically (H&E staining). Subsequently, levels of malondialdehyde (MDA) and glutathione (GSH), as markers of oxidative stress, were measured, and immunohistochemical expression of Caspase-3 and 8-hydroxy-2′-deoxyguanosine (8-OHdG) was analyzed. Results: In the IR group, significant histopathological alterations were observed, including villus atrophy and villus loss due to fusion, crypt loss, and mucosal degeneration. Additionally, there was an increase in MDA levels, a decrease in GSH levels, and a marked elevation in the expression of Caspase-3 and 8-OHdG. In the DEX-treated groups, particularly at the 200 µg/kg dose, significant improvements were noted in these parameters. It was determined that the histological architecture was largely preserved, oxidative stress was reduced, and apoptosis was suppressed. Conclusion: The findings suggest that DEX may effectively reduce X-ray-induced small intestinal injury in a dose-dependent manner, and that this effect is mediated through antioxidant and anti-apoptotic mechanisms. DEX holds potential for the prevention or treatment of radiation-induced gastrointestinal toxicities. Full article

Breast cancer (BC) is associated with multiple molecular factors such as overexpression of the beta-2 adrenergic receptor (ADRB2) and the overproduction of its agonists (norepinephrine and epinephrine). The role of adrenergic signaling in BC highlights the therapeutic potential of non-selective beta-blockers (nsBBs) as inhibitors of well-established protumor signaling pathways related to ADRB2 and their possible affinity for other important protumoral receptors. Our aim was to identify how nsBBs currently prescribed may also interact with receptors other than ADRB2, which are related to the pathophysiology of BC, using bioinformatic intracellular pathway analysis (BIPA). Subsequently, the affinity of nsBBs for both ADRB2 and the targets identified by BIPA was evaluated. We found that, beyond ADRB2, both receptor tyrosine kinase 2 (ERBB2) and neuropeptide Y receptor (NPYR) are promising targets for nsBBs in the adjuvant treatment of BC, according to BIPA. Docking studies showed that the nsBB with the highest binding affinity (ΔG) was carvedilol (−10.5 kcal/mol), followed by propranolol (−8.5 kcal/mol). These in silico findings suggest previously unrecognized pharmacological mechanisms for nsBBs in the possible treatment for BC. Notably, differences in receptor affinity were observed among the nsBBs, with carvedilol exhibiting the strongest binding affinity values on ADRB2, ERBB2, and NPYR as biological targets against BC cells. These promising results require future experimental validation. Full article

Bethanechol chloride, a nonselective muscarinic agonist, is the most frequently employed drug in dogs and cats to induce detrusor smooth muscle contraction under conditions characterized by poor or absent bladder emptying. Although this drug has minimal or absent nicotinic activity, at higher doses, weak stimulation of neuronal nicotinic receptors may occur, causing the release of noradrenaline, which induces contraction of the urethral smooth muscle by activating α-adrenergic receptors. In the presence of total or partial suprasacral lesions, the elaboration and initiation phase of the urination process is absent due to an interruption of afferent signals from the bladder to the brainstem. In such cases, hypertonicity of the urethral sphincters is expected, and bethanechol is contraindicated. Bethanechol is also not indicated for reflex dyssynergia. In the presence of complete injuries involving the sacral segments, cauda equina, or pelvic nerve, both reflex and voluntary micturition are abolished, and bethanechol is usually ineffective. However, in cases of partial injuries, bethanechol is likely to be effective, as partial integrity of the micturition reflex is required to produce sustained bladder contraction. Bethanechol may benefit patients with myopathic decompensated bladder, although its effectiveness depends on the severity of detrusor damage. Full article

Surgical procedures trigger dynamic inflammatory responses that influence postoperative pain, wound healing, and long-term outcomes. Conventional therapies rely on the systemic delivery of anti-inflammatory and analgesic agents, which often lack spatiotemporal precision and carry significant side effects. Inflammation-responsive hydrogels offer a promising alternative by enabling localized, stimulus-adaptive drug release aligned with the evolving biochemical milieu of surgical wounds. These smart biomaterials respond to endogenous triggers, such as reactive oxygen species, acidic pH, and proteolytic enzymes, allowing precise modulation of inflammation and tissue repair. This narrative review outlines the pathophysiological features of perioperative inflammation and the design principles of responsive hydrogel systems, including pH-, reactive oxygen species-, enzyme-sensitive, and multi-stimuli platforms. We evaluated the integration of key payloads, NSAIDs, corticosteroids, α₂-adrenergic agonists, and biologics, highlighting their therapeutic synergy and translational relevance. Preclinical studies across soft tissue, orthopedic, thoracic, and abdominal models have demonstrated the efficacy of these systems in modulating immune responses, reducing pain, and enhancing regeneration. Despite these encouraging results, challenges remain, including trigger fidelity, surgical compatibility, and regulatory readiness. Future advances in biosensor integration, logic-based design, and artificial intelligence-guided formulation may accelerate clinical translation. Inflammation-responsive hydrogels represent a transformative strategy for precise perioperative care. Full article

Metabolic syndrome (MetS) is a worldwide problem affecting at least one-third of the population. MetS patients have increased cardiovascular risk associated with an abnormal β-adrenergic response; however, it is not clear how MetS affects the cardiac β-adrenergic system. We analyzed cardiac function and the β-adrenergic response in an experimental model of MetS in rats by recording pressure–volume (PV) loops via an open-chest approach and performed a biochemical characterization of the cardiac β-adrenergic system through ELISA, radioligand binding assays, and Western blotting. Microscopy was employed to evaluate cardiac hypertrophy, fibrosis, and ultrastructure. MetS rats exhibited cardiac dysfunction, evidenced by a reduced cardiac output and ejection fraction, not explained by heart hypertrophy or fibrosis. MetS rats also had an elevated susceptibility to lethal arrhythmia following intra-cardiac administration of the non-selective β-adrenergic agonist isoproterenol, suggesting alterations in the β-adrenergic system. The total serum adrenaline and noradrenaline levels were higher in the MetS animals than those in the control group. The radioligand binding assays indicated no change in the βAR density; however, the Western blot analyses revealed decreased levels of Gα_s proteins and β-arrestin 1, but increased β₂AR and Gα_i protein levels. This study contributes to our understanding of how MetS can alter cardiac function, raising the risk of lethal arrhythmia induced by the β-adrenergic (fight or flight) response and underscores the relevance of therapeutically targeting MetS before its pathological progression toward cardiomyopathy. Full article

Background: Cerebral aneurysm (CA) is a focal or diffuse pathological dilation of the cerebral arterial wall that arises due to various etiological factors. It represents a serious vascular condition, particularly affecting the elderly, and carries a high risk of rupture and neurological morbidity. Clonidine (CL), an α2-adrenergic receptor agonist, has been reported to suppress aneurysm progression; however, its underlying molecular mechanisms, especially in relation to cerebral endothelial dysfunction, remain unclear. This study aimed to investigate the potential of CL to mitigate CA development by modulating apoptosis, inflammation, and oxidative stress in an Angiotensin II (Ang II)-induced endothelial injury model. Methods: Human brain microvascular endothelial cells (HBMECs) were used to establish an in vitro model of endothelial dysfunction by treating cells with 1 µM Ang II for 48 h. CL was administered 2 h prior to Ang II exposure at concentrations of 0.1, 1, and 10 µM. Cell viability was assessed using the MTT assay. Oxidative stress markers, including reactive oxygen species (ROS) and Nitric Oxide (NO), were measured using 2′,7′–dichlorofluorescin diacetate (DCFDA). Gene expression levels of vascular endothelial growth factor (VEGF), matrix metalloproteinases (MMP-2 and MMP-9), high mobility group box 1 (HMGB1), and nuclear factor kappa B (NF-κB) were quantified using RT-qPCR. Levels of proinflammatory cytokines; tumor necrosis factor-alpha (TNF-α), Interleukin-6 (IL-6), and interferon-gamma (IFN-γ); were measured using commercial ELISA kits. Results: Ang II significantly increased ROS production and reduced NO levels, accompanied by heightened proinflammatory cytokine release and endothelial dysfunction. MTT assay revealed a marked decrease in cell viability following Ang II treatment (34.18%), whereas CL preserved cell viability in a concentration-dependent manner: 44.24% at 0.1 µM, 66.56% at 1 µM, and 81.74% at 10 µM. CL treatment also significantly attenuated ROS generation and inflammatory cytokine levels (p < 0.05). Furthermore, the expression of VEGF, HMGB1, NF-κB, MMP-2, and MMP-9 was significantly downregulated in response to CL. Conclusions: CL exerts a protective effect on endothelial cells by reducing oxidative stress and suppressing proinflammatory signaling pathways in Ang II-induced injury. These results support the potential of CL to mitigate endothelial injury in vitro, though further in vivo studies are required to confirm its translational relevance. Full article

The development of biometric techniques in domestic animals has greatly advanced scientific practices in wildlife research. The association between seminal characteristics and body and testicular biometry enables the selection of suitable breeders, though appropriate measurement techniques are required. The present study assessed differences among conventional methods and formulas for estimating testicular parameters. Testicular length, width, and thickness were measured using three methods in 13 adult male domestic cats. Testicular area, volume, and weight were estimated, from which the gonadosomatic index (GSI) was calculated. Sperm were collected using an alpha-2 adrenergic agonist and urethral catheterization, and characterized in terms of volume, vigor, total motility, progressive motility, concentration, plasma membrane integrity, and morphology. The three methods were consistent in terms of testicular area, volume, weight, and GSI. Moderate positive correlations were observed for testicular weight (r = 0.61, p < 0.05) and GSI (r = 0.58, p < 0.05). Testicular parameters showed strong positive correlations among each other (r > 0.80, p < 0.05). We observed a moderate positive correlation between head length and progressive motility (r = 0.65, p < 0.05). In conclusion, all testicular measurement and estimation techniques showed comparable performance. Therefore, testicular biometry is useful for selecting breeding males in feline conservation programs, wherein larger body biometrics are related to improved seminal and reproductive parameters. Full article

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

Medetomidine, a veterinary α2-adrenergic agonist, has recently emerged as an adulterant in the non-medical opioid supply, yet human exposure has remained poorly characterized. We conducted a pragmatic retrospective cohort analysis utilizing chart review and liquid chromatography–tandem mass spectrometry (LC-MS/MS) toxicology testing on available urine samples from patients presenting to two hospitals in Philadelphia, PA, who fit two clinical phenotypes, intoxication or withdrawal. Samples also underwent glucuronidase pre-treatment to assess impact on the yield of medetomidine and xylazine metabolite detection. Testing identified universal exposure to medetomidine (58/58 samples) via the 3-hydroxy-medetomidine (3-OH-M) metabolite, post glucuronidase treatment and variable xylazine exposure (40/58 samples). Importantly, 32% of medetomidine exposures would have been missed without enzymatic pre-treatment. Patients exhibited two distinct clinical phenotypes: intoxication, characterized primarily by sedation; bradycardia; and often hypotension, and withdrawal, presenting with life-threatening tachycardia; hypertension and often encephalopathy. Notably, clinical phenotype correlated with urinary concentrations of 3-OH-M but not xylazine. These findings underscore the critical need for heightened clinical awareness and need for contemporaneous toxicologic screening mechanisms for medetomidine exposure, emphasizing its distinct clinical presentations and the potential public health implications posed by its widespread adulteration in illicit opioids. Full article

Cancer remains a leading cause of mortality worldwide, necessitating innovative therapeutic strategies. Drug repurposing offers a cost-effective approach to cancer treatment by identifying new anticancer applications for existing drugs. Terbutaline, a β2-adrenergic receptor agonist, and Milrinone, a phosphodiesterase-3 inhibitor, are traditionally used as positive inotropic agents but have shown potential anticancer effects. This review explores their mechanisms of action in cancer, focusing on their roles in modulating cyclic adenosine monophosphate (cAMP) levels, oxidative stress, and the tumor microenvironment. Terbutaline influences β2-adrenergic signaling, impacting cell proliferation, angiogenesis, and immune evasion. Milrinone, through PDE3 inhibition, elevates cAMP, promoting apoptosis and reducing tumor growth. Both agents exhibit anti-inflammatory and anti-angiogenic properties, suggesting their potential as adjuvant therapies in oncology. Despite promising preclinical data, clinical validation is required to confirm their efficacy and safety in cancer patients. This review highlights the therapeutic promise of repurposing Terbutaline and Milrinone, emphasizing the need for further research to optimize their application in cancer therapy. Full article

Endotoxemia often leads to microcirculatory derangement. In six sevoflurane anaesthetized Beagle dogs, we investigated the effects of 1 mg/kg of Escherichia coli lipopolysaccharide endotoxin intravenous and blood pressure (mean arterial pressure of 65 mmHg versus 85 mmHg) on microcirculation assessed on buccal mucosa using side stream dark field microscopy. Dogs were afterwards resuscitated with fluids and noradrenaline. We investigated dose requirements of noradrenaline with or without dexmedetomidine. Microcirculatory parameters, and markers of sepsis (cardiac output, mixed venous oxygen saturation, carbon dioxide gap, and lactate) were analysed before endotoxemia, after endotoxemia, after a 30 mL/kg of Ringer’s acetate fluid bolus, and during noradrenaline +/− dexmedetomidine infusion, after a second fluid bolus, and a second time after vasopressor treatment in a cross-over fashion. Endotoxemia and mean arterial pressure had no statistically significant effect on microcirculation; however, endotoxemia resulted in a decrease in cardiac output. Dexmedetomidine neither improved microcirculation nor reduced noradrenaline requirements. Full article