H2-receptor Research Articles

Histamine-tuned subicular circuit mediates alert-driven accelerated locomotion in mice.

The locomotive action involves diverse coordination, necessitating the integration of multiple motor neural circuits. However, the precise circuitry mechanism governing emotion-driven accelerated locomotion remains predominantly elusive. Here we dissect projections from the tuberomammillary nucleus (TMN) to subiculum (SUB) which promote alert-driven accelerated locomotion. We find that TMN histaminergic neurons respond to high-speed locomotion in both natural and alert acceleration. The TMN-SUB circuit is sufficient but not essential for amplifying accelerated locomotion from low to high-speed movement in basal condition, but it is both sufficient and necessary in alert condition for modulating accelerated locomotion during high-speed escape behavior. TMN histaminergic neuron activates SUB glutamatergic "fast locomotor cell" that projects to retrosplenial granular cortex (RSG) mainly through histamine H2 receptor (H2R). This study reveals the critical role of the histamine-tuned SUB circuit in alert-driven accelerated locomotion in mice, providing a theoretical foundation for comprehending neural circuit mechanisms of instinctive behaviors under alert.

Pharmaceutical Equivalence of Film-Coated and Chewable Tablets: A Comparative Dissolution Study Using Pulverized Chewable Tablets

Famotidine is a histamine H2 receptor antagonist used in the treatment of gastrointestinal disorders. It is available in multiple formulations, including film-coated tablets, chewable tablets, oral suspension, and injections. The purpose of this study was to develop and evaluate the film-coated tablet (FT) containing famotidine, magnesium hydroxide, and precipitated calcium carbonate, designed to be pharmaceutically equivalent to the marketed chewable tablet (CT). To achieve the pharmaceutical equivalence of two tablets, the dissolution profiles of FT should be similar to those of CT. However, since CT is intended to be chewed before swallowing, testing it in its intact form would not provide accurate results. Therefore, pulverized chewable tablets (PCT) were used as the reference product. The dissolution, performed by the paddle method at 50 rpm, was analyzed by the validated UV method. Similarity factor (f2) and difference factor (f1) were calculated to assess the equivalence of the dissolution profiles. The results demonstrated that the dissolution profiles of the FT and CT were similar. Additionally, the acid-neutralizing capacity test confirmed the equivalence of the two antacids. This study is one of the first to propose that dissolution tests for pharmaceutical equivalence should be conducted on pulverized CTs when developing generic equivalents to CTs.

Virtual Screening Approaches to Identify Promising Multitarget-Directed Ligands for the Treatment of Autism Spectrum Disorder

Autism spectrum disorder is a complex neurodevelopmental disorder. The available medical treatment options for autism spectrum disorder are very limited. While the etiology and pathophysiology of autism spectrum disorder are still not fully understood, recent studies have suggested that wide alterations in the GABAergic, glutamatergic, cholinergic, and serotonergic systems play a key role in its development and progression. Histamine neurotransmission is known to have complex interactions with other neurotransmitters that fit perfectly into the complex etiology of this disease. Multitarget-directed compounds with an affinity for the histamine H3 receptor indicate an interesting profile of activity against autism spectrum disorder in animal models. Here, we present the results of our research on the properties of (4-piperazin-1-ylbutyl)guanidine derivatives acting on histamine H3 receptors as potential multitarget ligands. Through the virtual screening approach, we identified promising ligands among 32 non-imidazole histamine H3 receptor antagonists/inverse agonists with potential additional activity against the dopamine D2 receptor and/or cholinesterases. The virtual screening protocol integrated predictions from SwissTargetPrediction, SEA, and PPB2 tools, along with molecular docking simulations conducted using GOLD 5.3 and Glide 7.5 software. Among the selected ligands, compounds 25 and 30 blocked radioligand binding to the D2 receptor at over 50% at a screening concentration of 1 µM. Further experiments allowed us to determine the pKi value at the D2 receptor of 6.22 and 6.12 for compounds 25 and 30, respectively. Our findings suggest that some of the tested compounds could be promising multitarget-directed ligands for the further research and development of more effective treatments for autism spectrum disorder.

Synthesis Methods of Loratadine and Its Clinical Application Comparison in Antihistamines

Loratadine is a second-generation antihistamine widely used in treating allergic diseases such as allergic rhinitis, urticaria, and conjunctivitis. Compared to first-generation antihistamines, loratadine has fewer central nervous system side effects, such as drowsiness and cognitive impairment, and exhibits prolonged efficacy. This paper comprehensively reviews the chemical structure, mechanism of action, and organic synthesis methods of loratadine. Loratadine’s tricyclic structure and selective binding to peripheral histamine H1 receptors allow it to effectively relieve allergic symptoms at low doses while minimizing side effects. The article also analyzes various classical and improved loratadine synthesis routes, comparing their advantages and disadvantages in terms of reaction conditions, yields, and environmental impact. By introducing novel catalysts and optimizing reaction conditions, the improved synthesis methods not only enhance yields and cost-effectiveness but also reduce environmental pollution. Additionally, this paper discusses the comparison of loratadine with other antihistamines in terms of efficacy and safety, highlighting its significant clinical advantages. Nonetheless, there remains a need for further optimization of its synthesis process and exploration of its potential in personalized treatment to meet the needs of different patients.

Amphetamine Derivatives as Potent Central Nervous System Multitarget SERT/NET/H3 Agents: Synthesis and Biological Evaluation

In this research, a variety of novel amphetamine derivatives were synthesized and assessed for their potential as multifaceted antidepressant agents. Among these compounds, compound 11b demonstrated potent inhibitory effects on both serotonin and noradrenaline transporters (SERT/NET) and high affinity for histamine H3 receptor (H3R), and displayed low affinity for off-target receptors (H1, α1) and hERG channels, which can reduce the prolongation of the QT interval. Molecular docking studies offered a rational binding model of compound 11b when it forms a complex with SERT, NET, and the histamine H3 receptor. In vivo behavioral studies, compound 11b dose-dependently reduced the immobility duration in the mouse FST and TST assays without a stimulatory effect on the locomotor activity. Furthermore, compound 11b had a favorable pharmacokinetic profile in rats. Thus, compound 11b has the potential to develop a novel class of drugs for the treatment of depression.

Cardioprotective effects of H3 receptor activation could be double-sided: insights from isoproterenol-induced cardiac injury.

Histamine H3 receptors (H3Rs) are known to modulate neurotransmitter release in the nervous system, but their role in cardiac injury remains unclear. The present study aimed to investigate the cardioprotective role of H3Rs in a mouse model of myocardial injury. Forty BALB/c male mice were divided into four groups: Control (SF), Isoproterenol (ISO), Imetit (IMT), and IMT + ISO. The IMT and IMT + ISO groups were pretreated orally with 10mg/kg imetit-dihydrobromide(imetit) for 7days. In the last 2days, the ISO and IMT + ISO groups received a subcutaneous injection of 85mg/kg isoproterenol to induce myocardial ischemia. Electrocardiogram (ECG) recordings were obtained, and heart tissues were analyzed histopathologically. The results demonstrated that the administration of imetit resulted in the prolongation of the PR interval in the IMT group. QRS and QT intervals were prolonged in the ISO group. The J-wave area in the ISO group was significantly larger than in the other groups. Histopathological analyses revealed the presence of small vacuoles, inflammatory cell infiltration, and collagen aggregates in cardiomyocytes in the ISO group. No significant cellular changes were observed in the IMT group, in contrast. The IMT + ISO group exhibited fewer ischemic findings than the ISO group. Immunohistochemical analyses revealed positive H3R immunoreactivity in all groups. Imetit pretreatment increased the immunoreactivity of H3Rs in both the IMT and IMT + ISO groups. The findings of this study suggest that H3Rs may be present on the postsynaptic side in cardiac myocytes, in addition to adrenergic presynaptic nerve endings. Furthermore, imetit has been found to significantly reduce the effects of myocardial ischemia by activating H3Rs. The better characterization of the postsynaptic role of H3Rs offers potential for the development of new therapeutic strategies.

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.