H2-receptor Research Articles

Impact of acid blocker therapy on growth, gut microbiome, and lung disease in young children with cystic fibrosis.

Acid blocker therapy (ABT) has become common in cystic fibrosis (CF), despite insufficient evidence for benefits and studies showing potentially negative effects. We examined associations between ABT usage and growth, gut microbiome (GM), and early-onset lung disease in young children with CF. One hundred forty-five infants with CF born during 2012-2017, diagnosed through newborn screening by age 3 months and followed to 36 months of age at six CF centers were evaluated. Longitudinal data on growth, pancreatic functional status, pulmonary symptoms, and acid blocker medications were prospectively collected. Early-onset lung disease severity was evaluated by a clinical scoring system. GM composition was assessed by 16S rRNA methodology. ABT use before age 3 years was frequent, with 81 (56%) of patients on H2 receptor antagonist (H2RA) or proton pump inhibitor (PPI), and higher among pancreatic insufficient (60%) versus pancreatic sufficient (26%) children. H2RA was commonly prescribed in infancy before transitioning to PPI. Growth improvements were not significantly greater, while GM α-diversity at 3 years of age was significantly lower and early-onset lung disease more severe, in persistent ABT users compared to nonusers of ABT. In our cohort of young children with CF, early and persistent ABT use was not associated with significant growth benefits and instead showed associations with reduced GM diversity and negative effects on early-onset lung disease. Consequentially, there is a critical need for systematic evaluation and comprehensive risk-benefit analysis of ABT to ensure proper guidelines for children with CF.

Pancreaticogastrostomy: A Safe and Effective Reconstruction Method After Pancreaticoduodenectomy: A Short Observational Study

Background: Pancreaticoduodenal resection is usually performed in patients with a localised small carcinoma in the head of the pancreas, at the lower end of the common bile duct or at the ampulla and occasionally for chronic pancreatitis.The mortality following pancreaticoduodenal resection has fallen and is now below 5% 1-6 .However, leakage from the anastomosis between pancreas and the jejunum has been and remains, one of the most worrying complications of the operation. The data from papers published in the last 8 years show that the incidence of pancreatic leak is 14% and the mortality of this complication 24%3,4,6-16 .Pancreaticogastrostomy is a potentially safer alternative to pancreaticojejunostomy in the reconstruction following Whipple's operation. Aim: The aim of the study was to observe pancreaticogastrostomy is a potentially safer alternative to pancreaticojejunostomy after pancreaticoduodenectomy. Methods: This prospective observational study was conducted at the Department of Surgery in Shaheed Suhrawardy Medical College Hospital, for One year (August 2021 to July 2022). Patients with a localised small carcinoma in the head of the pancreas, at the lower end of the common bile duct or at the ampulla, and occasionally for chronic pancreatitis admitted in the department of surgery were approached for inclusion in the study. Total 41 patients were selected according to inclusion and exclusion criteria. Informed written consent was taken from each patient. All patients underwent pancreaticogastrostomy. Detail clinical and demographic history was taken along with thorough physical examination relevant investigations. All patients were evaluated preoperatively and post operatively at discharge, 1 month and 3 months. Outcome was assessed post operatively. Collected data were checked and analysed in SPSS 23. Results: Two patients died within 30 days of the operation (mortality 4.9%), one from perioperative haemorrhage and another from septicaemia due to a biliary infection, which may have resulted from preoperative transhepatic biliary drainage. Both operations were carried out for carcinoma of the head of the pancreas. One patient developed a biliary leak which closed in 6 days. A postoperative pancreatic leak occurred in one patient with carcinoma of the ampulla; the fistula closed after 5 mdays, and did not delay his discharge from hospital. This patient remains well 36 months after operation, although he has now developed mild diabetes.One other patient developed diabetes mellitus postoperatively. This woman had evidence of obstructive pancreatitis at operation. She died 6 months later of recurrent carcinoma of the head of the pancreas. One patient with chronic pancreatitis has uncontrolled steatorrhoea, with up to four bowel movements a day. Four other patients take regular pancreatic supplements together with H2 receptor antagonists in order to maintain normal defaecation. There has been no case of stomal ulceration. None of the patients were lost to follow-up. The median survival for patients operated on for carcinoma of the head of the pancreas was 13 months, and for patients with carcinoma of the bile duct, 14 months. Median survival of patients with ampullary carcinoma was 38 months. Conclusion: Seventy two percent of patients had good outcome after Pancreaticogastrostomy(PG). Significant relief in symptoms of pain were noted after PG. Further larger study is recommended to validate this findings. J Shaheed Suhrawardy Med Coll 2023; 15(1): 66-72

Pharmacological inhibition of histamine N-methyltransferase extends wakefulness and suppresses cataplexy in a mouse model of narcolepsy.

Histamine, a neurotransmitter, plays a predominant role in maintaining wakefulness. Further, our previous studies showed that histamine N-methyltransferase (HNMT), a histamine-metabolising enzyme, is important for regulating brain histamine concentration. However, the effects of pharmacological HNMT inhibition on mouse behaviour, including the sleep-wake cycle and cataplexy, in a mouse model of narcolepsy have not yet been investigated. In the present study, we investigated the effects of metoprine, an HNMT inhibitor with high blood-brain barrier permeability, in wild-type (WT) and orexin-deficient (OxKO) narcoleptic mice. Metoprine increased brain histamine concentration in a time- and dose-dependent manner without affecting peripheral histamine concentrations. Behavioural tests showed that metoprine increased locomotor activity in both novel and familiar environments, but did not alter anxiety-like behaviour. Sleep analysis showed that metoprine increased wakefulness and decreased non-rapid eye movement (NREM) sleep through the activation of the histamine H1 receptor (H1R) in WT mice. In contrast, the reduction of rapid eye movement (REM) sleep by metoprine occurred independent of H1R. In OxKO mice, metoprine was found to prolong wakefulness and robustly suppress cataplexy. In addition, metoprine has a greater therapeutic effect on cataplexy than pitolisant, which induces histamine release in the brain, and has been approved for patients with narcolepsy. These data demonstrate that HNMT inhibition has a strong effect on wakefulness, demonstrating therapeutic potential against cataplexy in narcolepsy.

Photoinduced Copper-Catalyzed Cross-Coupling of Acylsilanes with Heteroarenes via Bimetallic Relay.

The transition metal-catalyzed direct coupling reactions involving electron-rich Fischer carbene species are largely underdeveloped and remain a big challenge. Here, a direct coupling reaction of azoles and azine N-oxides is reported with Fischer copper carbene species bearing an α-siloxy group i, which can be in situ generated from acylsilanes catalytically under photoirradiation and redox-neutral conditions. This coupling reaction between electron-rich α-siloxy Fischer Cu-carbene species with hard carbanion nucleophiles may undergo a bimetallic relay process, which is confirmed by the kinetic analysis and in situ NMR analysis. This reaction features mild conditions and remarkable heterocycle compatibility. Notably, this protocol tolerates a series of azole or azine N-oxide derivatives, including benzoxazole, benzothiazole, benzoimidazole, benzoisoxazole, oxazole, oxadiazole, triazolo[4,3-a]pyridine, purine, caffeine, pyridine N-oxide, quinoline N-oxide, pyrazine N-oxide, pyridazine N-oxide, etc. The synthetic value of this approach is demonstrated by the efficient synthesis of a histamine h4 receptor ligand and a marketed drug carbinoxamine.

Proton Pump Inhibitors Worsen Colorectal Cancer Outcomes in Patients Treated with Bevacizumab

Background: Approximately one-third of patients with advanced colorectal cancer (CRC) and treated with bevacizumab are prescribed proton pump inhibitors (PPIs) or H2 receptor antagonists (H2RAs). However, there is limited data on the effects of PPIs and H2RAs in these patients. To investigate the oncological outcomes of PPI and H2RA use in CRC patients treated with bevacizumab, we performed a retrospective cohort study using the Taiwan National Health Insurance Research Database and Taiwan Cancer Registry Database from 2005 to 2020. Methods: In CRC patients treated with bevacizumab, the PPI users and H2RA users were matched with patients without acid-reducing agents (ARAs) by 1:4 propensity score matching. PPI users and H2RA users were matched with propensity scoring in a 1:1 ratio. We divided patients into 4 cumulative PPI dosage levels to assess the dose–response relationship. The primary endpoints were 5-year overall survival and cancer-specific survival. Results: Compared with ARA non-users, both H2RA users and PPI users were associated with reduced overall survival. PPI users were associated with more significant negative effects on overall survival. Compared with H2RA users, PPI users were associated with lower 5-year overall survival (aHR: 1.19, 95% CI: 1.09–1.31) and cancer-specific survival (aHR: 1.20, 95% CI: 1.09–1.31). A similar dose–response relationship was observed for PPI users in terms of 5-year overall survival and cancer-specific overall survival. Conclusions: Compared to H2AR use, PPI use was associated with dose-dependent poorer oncological outcomes in metastatic CRC patients treated with bevacizumab.

Histamine H1-receptor-mediated modulation of NMDA receptors signaling responses.

This study attempted to clarify the role of histamine H1 receptors in epilepsy by exploring the effects of agonists and inverse agonists on the rundown of the current induced by iterative applications of NMDA or GABA in primary neuronal culture. Mepyramine, a classical H1-receptor antagonist/inverse agonist, increased the NMDA current by about 40% during the first minutes of recording. This effect was concentration-dependent, maximal at 10 nM, and mimicked by triprolidine, another antagonist/inverse agonist. No endogenous histamine was detected in the cultures by a selective immunoassay; both compounds were acting as inverse agonists. Indicating a high constitutive activity of the H1 receptor in this system, histamine did not affect the NMDA rundown, including its settlement, but significantly reversed the effect of mepyramine. A similar pattern was obtained with 2,3 bromophenyl histamine, a selective H1-receptor agonist. The initial increase induced by the two inverse agonists was followed by the same rundown as in controls. H1- and NMDA receptors are colocalized in most cultured neuronal cells. Mepyramine and histamine did not affect the GABA rundown. Our findings suggest an interaction between H1- and NMDA receptors. Inactivation of the H1-receptor by its inverse agonists delays the settlement of the NMDA rundown, which may underlie their proconvulsant effect reported in clinics. Therefore, H1-receptor constitutive activity and the effect of histamine revealed in its absence, tend to facilitate the initiation of the rundown, which is consistent with the anticonvulsant properties of histamine via activation of H1-receptors reported in many studies.

Pharmacokinetics, pharmacodynamics, and safety of izuforant, an H4R inhibitor, in healthy subjects: A phase I single and multiple ascending dose study.

Izuforant is a selective, and potent histamine H4 receptor (H4R) antagonist developed to treat atopic dermatitis (AD). There is an unmet medical need for therapeutic agents to control inflammation and pruritus. Izuforant is a strong candidate for this task based on the findings of non-clinical studies showing that inhibition of the histamine-mediated signaling pathway via H4R by izuforant results in decreased pruritus and inflammation. This study aimed to evaluate the clinical pharmacokinetic (PK) and pharmacodynamic (PD) profiles of izuforant. Dose-block-randomized, double-blind, placebo-controlled, single- and multiple ascending dose studies were conducted in 64 healthy volunteers. For the single ascending dose (SAD) study, 10-600 mg izuforant was administered to the designated groups. For the multiple ascending dose (MAD) study, 100-400 mg izuforant was administered to three groups. The clinical pharmacokinetic (PK) profile of izuforant was evaluated using plasma and urine concentrations. Blood sampling for the PD assay, which measured imetit-induced eosinophil shape changes (ESC), was also conducted. A one-compartment PK model described the distribution and elimination profiles of izuforant. An imetit-induced ESC inhibition test was established and validated for PD evaluation as a measure of the H4R antagonistic effect. ESC inhibition was observed even at doses as low as 10 mg; however, this inhibition became stronger and lasted longer as the dose increased. All izuforant doses were well tolerated, and no discontinuations due to adverse events (AE) or deaths were reported.

Anxiolytic- and antidepressive-like effects of harmaline in mice are mediated via histamine H3 receptor blockade

Many neuropsychiatric disorders can be caused by neurotransmitter dysfunction. Experimental studies have demonstrated that histamine and the harmaline affect physiological processes through interaction with other neurotransmitter systems. The objective of these experiments was to investigate the involvement of the histaminergic system in the effects of harmaline on anxiety- and depressive-related effects in male NMRI mice. Behavioral tests were employed to evaluate anxiety-related symptoms (elevated plus maze; EPM), depressive-like symptoms (forced swim test; FST), and cognitive decline (step-down test). The histamine H3 receptor (H3R) agonist α-methylhistamine dihydrobromide (α-MH; 5 mg/kg, i.p.) had anxiolytic- and depressive-like effects, while the H3R antagonist thioperamide (10 mg/kg, i.p.) showed an antidepressive-like property. The subthreshold dose of α-MH resulted in an increase in the tendency of mice treated with the harmaline (2.5 mg/kg) to remain in the EPM open-arms. A subthreshold dose of thioperamide (5 mg/kg) increased the time spent in the open-arms in mice treated with harmaline (2.5 and 5 mg/kg) while a high dose of harmaline decreased the immobility time. Furthermore, two higher doses of harmaline resulted in a reduction in the number of open-arm entries. Similarly, mice administered with thioperamide and a low dose of harmaline decreased locomotor activity in the EPM. Ultimately, the combined thioperamide and harmaline did not impair memory retrieval of mice. These experiments demonstrate that the histaminergic system is implicated in the anxiety- and depressive-related effects of harmaline. The combination of thioperamide and harmaline is effective in treating anxiety and depression without having an adverse effect on memory formation.

Hospitalized patients on proton pump inhibitors for stress ulcer prophylaxis have a higher risk of Clostridioides difficile infection compared with those on histamine-2 receptor antagonists

Previous studies on Clostridioides difficile infection (CDI) in proton pump inhibitor (PPIs) users generally enrolled a heterogeneous population and did not include a control group of histamine H2 receptor antagonists (H2RAs) users or adjust for confounding variables, such as previous antibiotics. It is uncertain whether hospitalized patients using PPIs for stress ulcer prophylaxis (SUP) are at a higher risk of CDI compared to those using H2RAs. This study aimed to compare the association between CDI and the usage of antisecretory drugs (ASDs): PPIs and H2RAs, for stress ulcer prophylaxis (SUP) among hospitalized patients, and the impact of the duration of their use on CDI. In this nationwide population-based cohort study using the Taiwan National Health Insurance Database, hospitalized patients using ASDs for SUP were identified between 2017-2018. A total of 63,266 and 69,269 individuals were included in the PPI and H2RA groups, respectively. The primary endpoint was a 90-day monitoring of CDI occurrence. The incidences of CDI were 1·6/10,000 and 0·5/10,000 person-days in the PPIs and H2RAs groups, respectively. After adjusting for confounding factors, the risk of infection in the PPIs group remained significantly higher than in the H2RAs group (Hazard ratio [HR], 2·49; 95% Confidence Interval [CI], 1·63-3·81). In the subgroup analysis, during hospitalization, the risk of CDI for patients using high-risk antibiotics or admitted intensive care unit (ICU), as well as patients with immunodeficiency, using PPIs for SUP, was higher than using H2RAs. Furthermore, the risk of CDI was higher in patients using ASDs for durations > 14 days than in those using them for < 7 days (adjusted HR, 3·66; 95% CI, 2·34-5·75). The risk of occurrence CDI for hospitalized patients using PPIs for SUP was higher than using H2RAs. It is recommended not to exceed 14 days of any gastric ASDs for SUP during hospitalization, especially for patients who have used high-risk antibiotics, been admitted to the ICU, or have immunodeficiency.

Comparison of the Efficacy and Safety of Bilastine 20mg versus Fexofenadine 180mg for Treatment of Perennial Allergic Rhinitis: Randomized Controlled Study.

Antihistamines has always remained the mainstay drug treatment for Allergic Rhinitis (AR). Bilastine is a novel, non-sedative antihistamine with a super-selective H1 receptor antagonist property. Both bilastine and fexofenadine are second generation antihistamine drugs commonly used to manage AR and Chronic Urticaria (CU). Autologous Skin Serum Test (ASST) is a practical test for histamine release in CU. These tests have been studied in AR patients with limited data studies. 114 patients diagnosed with perennial AR were recruited and divided into two groups of 57 each. One group was started Bilastine 20mg once a day and other group, fexofenadine 180mg once a day. Total Nasal Symptom Score (TNSS) was calculated at presentation and two weeks of antihistamine therapy. ASST was hypothesized to be the test for AR and performed at the time of presentation and at two weeks follow-up. Intergroup and Intragroup assessment of TNSS, ASST and its variables were done using unpaired and paired t test respectively. Patients showed reduction in symptoms of AR with both antihistamines. A significant improvement of sneezing and rhinorrhoea was seen in Fexofenadine group as compared to Bilastine group. TNSS showed statistically significant improvement in both the groups. ASST had statistically significant reduction in both the groups. Both Bilastine and fexofenadine were found to be effective in reduction of symptoms of allergic rhinitis. Bilastine was found to be more effective in overall as well as sneezing and rhinorrhoea noted two weeks after therapy. The online version contains supplementary material available at 10.1007/s12070-024-04770-0.

Cetirizine platinum(IV) complexes with antihistamine properties inhibit tumor metastasis by suppressing angiogenesis and boosting immunity

The histamine (HA) in tumors plays critical roles in promoting metastasis. Herein, a series of cetirizine (CTZ) platinum(IV) complexes with antihistamine properties were developed as antimetastatic agents. Dual CTZ platinum(IV) complex with cisplatin core was screened out as a candidate displaying potent antiproliferative activities. More importantly, it exerted promising antimetastatic properties both in vitro and in vivo. Investigation of the mechanism revealed that serious DNA damage was induced, which further led to the upregulation of histone H2AX (γ-H2AX) and P53. The mitochondria-mediated apoptosis was ignited through the B-cell lymphoma-2 (Bcl-2)/Bcl-2 associated X protein (Bax)/caspase3 pathway. Moreover, the HA-histamine receptor H1 (HRH1) axis was inhibited, then the key signaling phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) was suppressed. Subsequently, the angiogenesis in tumors was restrained by suppressing the inflammatory and hypoxic microenvironment. Then, the antitumor immunity was reinforced by increasing the CD3+ and CD8+ T cells and promoting the polarization of macrophages from M2- to M1-type, which was associated with the blockade of programmed cell death ligand-1 (PD-L1) expression in tumors.

Omalizumab for Treatment of Anti-GD2 Antibody-related Urticaria.

Outcomes for high-risk neuroblastoma have improved with the addition of antidisialoganglioside (GD2) antibody-mediated immunotherapy to multimodality therapy. Urticaria is an expected side effect of anti-GD2 immunotherapy. Rarely, despite maximal use of antihistamines and H2 receptor antagonists, refractory urticaria can result in impaired quality of life, and delays or discontinuation of immunotherapy. The anti-IgE monoclonal antibody, omalizumab, is approved for the treatment of asthma and chronic spontaneous urticaria. We successfully managed grade 3, naxitamab-related urticaria refractory to standard management in 2 patients using omalizumab, allowing for continued anti-GD2 immunotherapy. Omalizumab did not impact antitumor activity or immunogenicity of naxitamab.

Comprehensive analysis of nizatidine: Pharmacodynamics and pharmacokinetics in anti-ulcer treatment

Ulcers are characterized histologically as lesions that penetrate through the muscularis mucosae into the submucosal layer, affecting any segment of the gastrointestinal (GI) tract mucosa. They often arise due to excessive acid production from peptic secretions. Nizatidine (NZT) is a potent H2-receptor antagonist used to reduce basal, nocturnal, and stimulated gastric acid secretion. This medication is commonly prescribed for conditions such as gastroesophageal reflux disease, peptic ulcers, and duodenal ulcers. As a member of the histamine H2 receptor antagonist class introduced before proton pump inhibitors, Nizatidine is noted for its effectiveness comparable to ranitidine. However, Nizatidine is distinguished by its thiazole ring, in contrast to the furan ring found in ranitidine. When administered orally, Nizatidine, especially in combination with antacids, enhances drug delivery to parietal cell receptors, improving the overall bioavailability of the medication and its ability to suppress acid secretion. Nizatidine is primarily absorbed in the proximal small intestine, exhibiting about 70% absolute bioavailability. Its lower absorption from the colon and a short biological half-life (ranging from 1 to 1.6 hours) suggest the potential benefits of developing sustained-release formulations such as floating gels to prolong its therapeutic effects. Clinical studies indicate that Nizatidine, in doses of 300 mg at bedtime or 150 mg twice daily, shows superior efficacy compared to other H2-receptor antagonists for managing duodenal and gastric ulcers as well as gastroesophageal reflux disease.

Therapeutic potential of histamine H4 receptor antagonist as a preventive treatment for diabetic retinopathy in mice

Diabetic retinopathy (DR) is a prevalent complication of diabetes, often resulting in vision loss and blindness. Existing treatments primarily aim to control blood sugar levels and inhibit angiogenesis. However, current therapies for DR, such as anti-VEGF and laser photocoagulation, are frequently invasive, and can cause adverse side effects. Consequently, there is a critical need for new preventive therapeutics to address DR more effectively. This study aimed to examine the therapeutic potential of a histamine H4 receptor (HRH4) antagonist as a preventive treatment for DR in mice. A mouse model of DR was established by intraperitoneally injecting 200 mg/kg of streptozotocin (STZ). Immune cell infiltration into the retina of mice with STZ-induced diabetes was measured using fluorescence-activated cell sorting (FACS) 12 weeks after STZ injection. The preventive effects of the HRH4 antagonist on inflammation and pathological retinal vessel leakage were determined in a mouse model of DR. Infiltration of HRH4-expressing macrophages increased in the retina of mice with STZ-induced DR. The HRH4 antagonist prevented macrophage infiltration and retinal vascular leakage to prevent STZ-induced DR in mice without causing any retinal toxicity. The infiltration of macrophages increased in the retina of mice with STZ-induced diabetes through HRH4, indicating that HRH4 is potentially a novel preventative therapeutic target in DR. These findings suggest that targeting HRH4 is a promising strategy for the prevention and treatment of DR.

Alleviation of Autophagic Deficits and Neuroinflammation by Histamine H3 Receptor Antagonist E159 Ameliorates Autism-Related Behaviors in BTBR Mice

Background/Objectives: Autism spectrum disorder (ASD) is a neurodevelopmental condition marked by social interaction difficulties, repetitive behaviors, and immune dysregulation with elevated pro-inflammatory markers. Autophagic deficiency also contributes to social behavior deficits in ASD. Histamine H3 receptor (H3R) antagonism is a potential treatment strategy for brain disorders with features overlapping ASD, such as schizophrenia and Alzheimer’s disease. Methods: This study investigated the effects of sub-chronic systemic treatment with the H3R antagonist E159 on social deficits, repetitive behaviors, neuroinflammation, and autophagic disruption in male BTBR mice. Results: E159 (2.5, 5, and 10 mg/kg, i.p.) improved stereotypic repetitive behavior by reducing self-grooming time and enhancing spontaneous alternation in addition to attenuating social deficits. It also decreased pro-inflammatory cytokines in the cerebellum and hippocampus of treated BTBR mice. In BTBR mice, reduced expression of autophagy-related proteins LC3A/B and Beclin 1 was observed, which was elevated following treatment with E159, attenuating the disruption in autophagy. The co-administration with the H3R agonist MHA (10 mg/kg, i.p.) reversed these effects, highlighting the role of histaminergic neurotransmission in observed behavioral improvements. Conclusions: These preliminary findings suggest the therapeutic potential of H3R antagonists in targeting neuroinflammation and autophagic disruption to improve ASD-like behaviors.

Pharmacological intervention of behavioural traits and brain histopathology of prenatal valproic acid-induced mouse model of autism.

Autism spectrum disorder (ASD) is one of the leading causes of distorted social communication, impaired speech, hyperactivity, anxiety, and stereotyped repetitive behaviour. The aetiology of ASD is complex; therefore, multiple drugs have been suggested to manage the symptoms. Studies with histamine H3 receptor (H3R) blockers and acetylcholinesterase (AchE) blockers are considered potential therapeutic agents for the management of various cognitive impairments. Therefore, the aim of this study was to evaluate the neuro-behavioural effects of Betahistine, an H3R antagonist, and Donepezil, an acetylcholinesterase inhibitor on Swiss albino mouse model of autism. The mice were intraperitoneally injected with valproic acid (VPA) on the embryonic 12.5th day to induce autism-like symptoms in their offspring. This induced autism-like symptoms persists throughout the life. After administration of different experimental doses, various locomotor tests: Open Field, Hole-Board, Hole Cross and behavioural tests by Y-Maze Spontaneous Alternation and histopathology of brain were performed and compared with the control and negative control (NC1) groups of mice. The behavioural Y-Maze test exhibits significant improvement (p <0.01) on the short term memory of the test subjects upon administration of lower dose of Betahistine along with MAO-B inhibitor Rasagiline once compared with the NC1 group (VPA-exposed mice). Furthermore, the tests showed significant reduction in locomotion in line crossing (p <0.05), rearing (p <0.001) of the Open Field Test, and the Hole Cross Test (p <0.01) with administration of higher dose of Betahistine. Both of these effects were observed upon administration of acetylcholinesterase inhibitor, Donepezil. Brain-histopathology showed lower neuronal loss and degeneration in the treated groups of mice in comparison with the NC1 VPA-exposed mice. Administration of Betahistine and Rasagiline ameliorates symptoms like memory deficit and hyperactivity, proving their therapeutic effects. The effects found are dose dependent. The findings suggest that H3R might be a viable target for the treatment of ASD.

Mathematical model of the relationship between pH holding time and erosive esophagitis healing rates.

Effective suppression of gastric acid secretion promotes healing of erosive esophagitis. Treatment guidelines recommend proton pump inhibitors (PPIs) and histamine H2-receptor antagonists (H2RAs). Emerging evidence also supports potassium-competitive acid blockers (P-CABs). The aim was to construct a mathematical model to examine the relationship between pH holding time ratios (HTRs) and erosive esophagitis healing rates with H2RAs, PPIs and P-CABs. By literature search, we identified studies of H2RAs, PPIs or P-CABs that reported mean pH >4 HTRs at steady state (days 5-8) and erosive esophagitis healing rates after 4 and/or 8 weeks. We aggregated treatments by drug class and developed a non-linear, mixed-effects model to explore the relationship between pH >4 HTRs and healing rates. The pH dataset included 82 studies (4297 participants; 201 dosage arms); healing rate data came from 103 studies (43,417 patients; 196 treatment arms). P-CABs achieved the longest periods with intragastric pH >4, and the highest healing rates after 4 and 8 weeks. The predicted probabilities of achieving ≥90% healing rates at 8 weeks were 74.1% for P-CABs, 17.3% for PPIs and 0% for H2RAs. P-CABs provide the longest duration with intragastric pH >4 and, accordingly, the highest healing rates of erosive esophagitis.

Bis(benzimidazol-2-yl)amine-Based DPP-4 Inhibitors Potentially Suitable for Combating Diabetes and Associated Nervous System Alterations.

Bis(benzimidazol-2-yl)amine scaffold is not present in dipeptidyl peptidase-4 (DPP-4) inhibitors published so far. Herein, the inhibitory potential of bis(benzimidazol-2-yl)amine derivatives against DPP-4 was evaluated. In non-competitive inhibition mode, three representatives 5, 6, and 7 inhibited DPP-4 in vitro with IC50 values below 50 μM. The assessed binding pocket of DPP-4 for these benzimidazoles includes the S2 extensive subsite's residues Phe357 and Arg358. None of the lead compounds showed cytotoxicity to human neuroblastoma SH-SY5Y cells at concentrations lower than 10 μM. None showed significant binding affinity at dopamine D2, D3, and histamine H1, H3 receptors, at concentrations lower than 10 μM, leading to preferable outcomes due to mutually opposite effects of these neurotransmitters on each other. The potential beneficial effects on dopamine synthesis and the survival of dopaminergic neurons could be mediated by DPP-4 inhibition. These effective noncompetitive DPP-4 inhibitors, with inhibitory potential better than reference diprotin A (relative inhibitory potency compared to diprotin A is 3.39 and 1.54 for compounds 7 and 5, respectively), with the absence of cytotoxicity to SH-SY5Y cells, are valuable candidates for further evaluation for the treatment of diabetes and associated disruption of neuronal homeostasis.

Stimulation of central histaminergic transmission attenuates diazepam-induced motor disturbance on rota-rod and beam walking tests in mice.

Diazepam administration has been shown to influence the release of histamine in various brain areas involved in motor behavior. Therefore, the present study explored the plausible regulatory role of the central histaminergic system in diazepam-induced deficits in motor performance in mice using the rota-rod and beam walking tests. In this study, several doses of diazepam (0.5, 1, 2, and 3 mg/kg, i.p.) were assessed in mice for changes in motor performance on the rota-rod and beam walking test. In addition, the brain histamine levels were determined after diazepam administration, and the diazepam-induced motor deficits were assessed in mice, pretreated centrally (intracerebroventricular) with histaminergic agents such as histamine (0.1, 10 µg), histamine precursor (L-histidine: 0.1, 2.5 µg), histamine neuronal releaser/H 3 receptor antagonist (thioperamide: 0.5, 10 µg), H 1 and H 2 receptor agonist [2-(3-trifluoromethylphenyl) histamine (FMPH: 0.1, 6.5 µg; amthamine: 0.1, 5 µg)/antagonist (H 1 : cetirizine 0.1 µg) and (H 2 : ranitidine: 50 µg)]. Results indicate that mice treated with diazepam at doses 1, 2 mg/kg, i.p. significantly increased the brain histamine levels. Moreover, in mice pretreated with histaminergic transmission-enhancing agents, the diazepam (2 mg/kg, i.p.)-induced motor incoordination was significantly reversed. Contrastingly, diazepam (1 mg/kg, i.p.) in its subeffective dose produced significant motor deficits in mice preintracerebroventricular injected with histamine H 1 and H 2 receptor antagonists on both the employed tests. Therefore, it is postulated that endogenous histamine operates via H 1 and H 2 receptor activation to alleviate the motor-impairing effects of diazepam.

Betahistine's Neuroprotective Actions against Lipopolysaccharide-Induced Neurotoxicity: Insights from Experimental and Computational Studies.

Histamine H3 receptor (H3R) antagonists, such as betahistine (BHTE), have shown significant potential in treating central nervous system (CNS) disorders due to their neuroprotective properties. This study investigated BHTE's effects on lipopolysaccharide (LPS)-induced neurotoxicity, which is associated with neuroinflammation and neurodegeneration. Rats were divided into groups and pre-treated with BHTE (5 or 10 mg/kg, p.o.) for 30 days, followed by LPS administration (1 mg/kg, i.p.) for 4 consecutive days to induce neurotoxicity. LPS exposure resulted in cognitive impairment, as evidenced by performance deficits in maze tests, and a significant reduction in brain acetylcholine (ACh) levels. Additionally, LPS led to increased neuroinflammation, oxidative stress, mitochondrial dysfunction, and apoptosis. Pre-treatment with BHTE effectively counteracted these effects, improving cognitive performance and restoring ACh levels. BHTE significantly reduced LPS-induced increases in pro-inflammatory markers (COX-2, TNF-α, and IL-6) while enhancing anti-inflammatory cytokines (IL-10 and TGF-β1). Furthermore, BHTE improved mitochondrial function by increasing enzyme levels (MRCC-I, II, and IV) and boosted anti-apoptotic (Bcl-2) and antioxidant defenses (GSH and catalase). BHTE also reduced apoptosis markers, including pro-apoptotic protein caspase-3, and oxidative stress marker malondialdehyde (MDA). Molecular modeling studies revealed that BHTE effectively binds to key enzymes involved in neuroinflammation and apoptosis (AChE, COX-2, and caspase-3), with binding free energies between 4 and 5 kcal/mol, interacting with critical residues. These findings underscore BHTE's multifaceted neuroprotective effects against LPS-induced neurotoxicity, offering potential therapeutic avenues for managing neuroinflammation and related neurodegenerative disorders.