Antiinflammatory effects of H1-antihistamines: clinical and immunological relevance

Novel drug-drug salt crystals of metformin with ibuprofen or naproxen: Improved solubility, dissolution rate, and synergistic antinociceptive effects

As the monotherapy of available analgesics is usually accompanied by serious side effects or limited efficacy in the management of chronic pain, multimodal analgesia is widely used to achieve improved benefit-to-risk ratios in clinic. Drug-drug salts are extensively researched to optimize the physicochemical properties of active pharmaceutical ingredients (APIs) and achieve clinical benefits compared with individual APIs or their combination. New drug-drug salt crystals metformin-ibuprofen (MET-IBU) and metformin-naproxen (MET-NAP) were prepared from metformin (MET) and two poorly water-soluble anti-inflammatory drugs (IBU and NAP) by the solvent evaporation method. The structures of these crystals were confirmed by single crystal and powder X-ray diffraction, Hirshfeld surface, Fourier transform infrared spectroscopy and thermal analysis. Both MET-IBU and MET-NAP showed significantly improved solubility and intrinsic dissolution rate than the pure IBU or NAP. The stability test indicated that MET-IBU and MET-NAP have excellent physical stability under stressing test (10 days) and accelerated conditions (3 months). Moreover, isobolographic analysis suggested that MET-IBU and MET-NAP exerted potent and synergistic antinociceptive effects in λ-Carrageenan-induced inflammatory pain in mice, and both of them had an advantage in rapid pain relief. These results demonstrated the potential of MET-IBU and MET-NAP to achieve synergistic antinociceptive effects by developing drug-drug salt crystals.

Flupirtine and antihistamines exert synergistic anti-nociceptive effects in mice

RATIONALE

Drug combinations are commonly used in pain management, which can produce potent analgesic effects with reduced dosage and adverse effects.

OBJECTIVE

This study was designed to evaluate the anti-nociceptive effects and adverse effects of new combinations of flupirtine (a Kv7 potassium channel opener) and antihistamines (promethazine, fexofenadine) on acute and chronic pain in mice, and the possible mechanisms behind the synergistic analgesic effects were preliminarily investigated.

METHODS

In acetic acid writhing test, carrageenan-induced inflammatory pain model, and paclitaxel-induced neuropathic pain model, the interaction indexes (γ) between flupirtine and antihistamines were determined by isobolographic analysis. Furthermore, the Kv7 channel blocker XE991 was used to determine whether the effects of single agents and drug combinations on paclitaxel- and carrageenan-induced mechanical allodynia were mediated by Kv7 channels. Finally, hepatotoxicity markers, liver histopathology, and the rotarod test were used to investigate the adverse effects of drugs in combination doses.

RESULTS

The interaction indexes of flupirtine-promethazine and flupirtine-fexofenadine in all the above three pain models were lower than 1. The analgesic effects of flupirtine (13 mg/kg), promethazine (5 mg/kg), fexofenadine (20 mg/kg), and their combinations were antagonized significantly by XE991 (3 mg/kg). And the adverse effects of flupirtine and antihistamines in combination doses were not significantly different from the vehicle group.

CONCLUSIONS

Flupirtine and antihistamines produced synergistic analgesic effects in all the above pain models. The analgesic effects of antihistamines were partially mediated by Kv7/M channels, and the activation of Kv7/M channels may be partly responsible for the synergistic analgesic effects between flupirtine and antihistamines.

Histamine H3 receptor antagonists - Roles in neurological and endocrine diseases and diabetes mellitus

Human histamine H3 receptor (H3R) was initially described in the brain of rat in 1983 and cloned in 1999. It can be found in the human brain and functions as a regulator of histamine synthesis and release. H3 receptors are predominantly resident in the presynaptic region of neurons containing histamine, where they modulate the synthesis and release of histamine (autoreceptor) or other neurotransmitters such as dopamine, norepinephrine, gamma-aminobutyric acid (GABA), glutamate, acetylcholine and serotonin (all heteroreceptors). The human histamine H3 receptor has twenty isoforms of which eight are functional. H3 receptor expression is seen in the cerebral cortex, neurons of the basal ganglia and hippocampus, which are important for process of cognition, sleep and homoeostatic regulation. In addition, histamine H3R antagonists stimulate insulin release, through inducing the release of acetylcholine and cause significant reduction in total body weight and triglycerides in obese subjects by causing a feeling of satiety in the hypothalamus. The ability of histamine H3R antagonist to reduce diabetes-induced hyperglycaemia is comparable to that of metformin. It is reasonable therefore, to claim that H3 receptor antagonists may play an important role in the therapy of disorders of cognition, the ability to sleep, oxidative stress, inflammation and anomaly of glucose homoeostasis. A large number of H3R antagonists are being developed by pharmaceutical companies and university research centres. As examples of these new drugs, this review will discuss a number of drugs, including the first histamine H3R receptor antagonist produced.

Use of H-1 Antihistamine in Dermatology: More than Itch and Urticaria Control: A Systematic Review

H-1 antihistamines are commonly used in dermatological practice for itch and urticaria control. The widespread expression of H-1 receptor on different cells in the skin and various biologic functions of H-1 antihistamines indicate the possible treatment potentials of H-1 antihistamines in dermatology. A literature search was performed on PubMed and Embase, targeting articles reporting use of antihistamine for purposes other than itch and urticaria control in dermatological practice. Several off-label usages of antihistamines were identified, including alopecia, acne, Darier disease, eosinophilic dermatoses, paraneoplastic dermatoses, psoriasis, lichen nitidus, radiation dermatitis, skin dysesthesia, and cutaneous malignancies. Additional benefits were observed when H-1 antihistamines were used either alone or in combination with other therapeutic modalities. Although various novel uses of H-1 antihistamines have been uncovered, the evidence level of most included studies is weak. Further randomized control trials are warranted to better evaluate the efficacy and dosage of H-1 antihistamine for dermatological disorders.

Selecting optimal second-generation antihistamines for allergic rhinitis and urticaria in Asia

Background

Allergic diseases are on the rise in many parts of the world, including the Asia–Pacific (APAC) region. Second-generation antihistamines are the first-line treatment option in the management of allergic rhinitis and urticaria. International guidelines describe the management of these conditions; however, clinicians perceive the additional need to tailor treatment according to patient profiles. This study serves as a consensus of experts from several countries in APAC (Hong Kong, Malaysia, the Philippines, Singapore, Thailand, Vietnam), which aims to describe the unmet needs, practical considerations, challenges, and key decision factors when determining optimal second-generation antihistamines for patients with allergic rhinitis and/or urticaria.

Methods

Specialists from allergology, dermatology, and otorhinolaryngology were surveyed on practical considerations and key decision points when treating patients with allergic rhinitis and/or urticaria.

Results

Clinicians felt the need for additional tools for diagnosis of these diseases and a single drug with all preferred features of an antihistamine. Challenges in treatment include lack of clinician and patient awareness and compliance, financial constraints, and treatment for special patient populations such as those with concomitant disease. Selection of optimal second-generation antihistamines depends on many factors, particularly drug safety and efficacy, impact on psychomotor abilities, and sedation. Country-specific considerations include drug availability and cost-effectiveness. Survey results reveal bilastine as a preferred choice due to its high efficacy and safety, suitability for special patient populations, and the lack of sedative effects.

Conclusions

Compliance to the international guidelines is present among allergists, dermatologists and otorhinolaryngologists; however, this is lower amongst general practitioners (GPs). To increase awareness, allergy education programs targeted at GPs and patients may be beneficial. Updates to the existing international guidelines are suggested in APAC to reflect appropriate management for different patient profiles and varying symptoms of allergic rhinitis and urticaria.

Electronic supplementary material

The online version of this article (doi:10.1186/s12948-017-0074-3) contains supplementary material, which is available to authorized users.

Chlorpheniramine attenuates histamine-mediated aquaporin 5 downregulation in human nasal epithelial cells via suppression of NF-κB activation

Background: Aquaporin 5 (AQP5) is most likely the primary water channel in the human nasal mucosa and acts as a key tight junction protein. The signaling cascades responsible for AQP5 regulation are still works in progress. Objective: This study sought to determine the effects of histamine and chlorpheniramine on AQP5 expression in human nasal epithelial cells (HNEpC) and to detect the signaling cascades responsible for these effects. Methods: HNEpC were cultured with four concentrations of histamine or chlorpheniramine in vitro. The sub-cellular distribution of AQP5 was explored using immunocytochemistry. The pharmacologic effects of histamine and chlorpheniramine on the expression of the phosphorylation of cyclic adenosine monophosphate-responsive element binding protein (p-CREB), the AQP5 and the NF-κB protein were examined using Western blotting. Results: AQP5 was found to be located in cell membrane and cytoplasm and present in every group without significant difference. Histamine inhibits the expression of AQP5 and p-CREB in HNEpC, while chlorpheniramine dose-dependently increases these protein levels with statistical significance. HNEpC treated with histamine and chlorpheniramine in turn showed the same trends as those intervened separately with these two drugs. Moreover, chlorpheniramine had the ability to reverse the inhibitory effect of histamine. Western blotting analysis revealed that after incubation with 10^-4 M histamine, NF-κB protein was significantly heightened by 165% compared with the untreated control group. Again, such increase can be significantly reversed after chlorpheniramine treatment. Conclusions: The current study demonstrated that histamine inhibits CREB phosphorylation in HNEpC, which results in decreased AQP5 expression via activation of NF-κB pathway. Chlorpheniramine attenuates the inhibitory effect of histamine in p-CREB/AQP5 expression via suppression of NF-κB signal cascades. This observation could provide additional insight into the anti-inflammatory effects of H1-antihistamines that contribute to maintain airway surface liquid and mucosal defense.

Anti-allergic and anti-inflammatory properties of a potent histamine H1 receptor antagonist, desloratadine citrate disodium injection, and its anti-inflammatory mechanism on EA.hy926 endothelial cells

The present study, demonstrates that, desloratadine citrate disodium injection (DLC) possesses antihistaminic, anti-allergic and anti-inflammatory properties and elucidates its molecular mechanisms of anti-inflammatory properties. In vitro antihistamine activity of DLC was determined in guinea pig isolated tissues. In vivo antihistamine effects were evaluated after following intravenous administration of DLC in mice with histamine- induced paw edema and in rats with increased capillary permeability. Anti-allergic effects were assessed through passive cutaneous anaphylactic (PCA) reactions in sensitized rodents and ovalbumin-induced allergic rhinitis in rats. Anti-inflammatory properties and molecular mechanisms of DLC were determined on histamine- and lipopolysaccharide (LPS)-induced EA.hy926 endothelial cells. DLC exhibited significant and reversible inhibition of histamine-induced contractions of isolated guinea pig ileum with pA2 value of 8.88. Histamine-induced paw edema and increased capillary permeability were notably inhibited by DLC intravenous administration. In the model of PCA reactions, DLC showed significant activity in a dose-dependent nd potently inhibited both the early-phase and late-phase allergic reaction of ovalbumin-induced allergic rhinitis in rats. DLC alleviated the rhinitis symptoms and inhibited inflammatory cell infiltration, IL-4 and protein leakage in nasal lavage fluid (NLF). In EA.hy926 cells, DLC significantly inhibited the histamine- and LPS- induced IL-6 and IL-8 production and P-selectin and intercellular cell adhesion molecule-1 (ICAM-1) expression. Moreover, DLC reduced translocation of nuclear factor-kappaB (NF-κB) to the nucleus in activated EA.hy926 cells. These results provide evidence that DLC possesses potent antihistaminic, anti-allergic and, anti-inflammatory properties via suppressing IL-6, IL-8, P-selectin and ICAM-1 expression.

Are pharmaceuticals with evolutionary conserved molecular drug targets more potent to cause toxic effects in non-target organisms?

The ubiquitous use of pharmaceuticals has resulted in a continuous discharge into wastewater and pharmaceuticals and their metabolites are found in the environment. Due to their design towards specific drug targets, pharmaceuticals may be therapeutically active already at low environmental concentrations. Several human drug targets are evolutionary conserved in aquatic organisms, raising concerns about effects of these pharmaceuticals in non-target organisms. In this study, we hypothesized that the toxicity of a pharmaceutical towards a non-target invertebrate depends on the presence of the human drug target orthologs in this species. This was tested by assessing toxicity of pharmaceuticals with (miconazole and promethazine) and without (levonorgestrel) identified drug target orthologs in the cladoceran Daphnia magna. The toxicity was evaluated using general toxicity endpoints at individual (immobility, reproduction and development), biochemical (RNA and DNA content) and molecular (gene expression) levels. The results provide evidence for higher toxicity of miconazole and promethazine, i.e. the drugs with identified drug target orthologs. At the individual level, miconazole had the lowest effect concentrations for immobility and reproduction (0.3 and 0.022 mg L-1, respectively) followed by promethazine (1.6 and 0.18 mg L-1, respectively). At the biochemical level, individual RNA content was affected by miconazole and promethazine already at 0.0023 and 0.059 mg L-1, respectively. At the molecular level, gene expression for cuticle protein was significantly suppressed by exposure to both miconazole and promethazine; moreover, daphnids exposed to miconazole had significantly lower vitellogenin expression. Levonorgestrel did not have any effects on any endpoints in the concentrations tested. These results highlight the importance of considering drug target conservation in environmental risk assessments of pharmaceuticals.

Does treatment of the laryngeal mucosa reduce dystonic symptoms? A prospective clinical cohort study of mannose binding lectin and other immunological parameters with diagnostic use of phonatory function studies

This study examined efficacy of the innate immune defence via the mannose binding lectin (MBL) in a cohort of 55 dystonic patients prospectively referred to the clinic with laryngeal mucosal complaints, who were placed on local steroids (budesonid inhaler, 400 μg 2 times daily) and antihistamines (fexofenadin 180 mg mostly 3 times daily) with adjuvant lifestyle corrections. Treatment efficacy of the larynx was assessed based on mucosal findings of the vocal folds examined with phonatory function studies (PhFS) comprising simultaneous high-speed digital images, kymography, electroglottography and voice acoustics combined with a visual score of arytenoids oedema, as these measures are indicative of the magnitude of laryngitis. Lactose and gluten intolerance and immunological analyses of the innate system were made systematically. Results showed that the genetic aspects of immunology did not reveal a role for the innate immune system, represented by the MBL. But an unexpected positive effect of the larynx treatment on dystonia symptoms was found evidenced by reduction of dystonic complaints and more normative results of PhFS, and a reduction of oedema of the inter arytenoids region. Symptoms relieve and better quality of life was observed on follow-up for the dystonia complaints.

Characterization and function of histamine receptors in human bone marrow stromal cells

There are several clinical trials worldwide using bone marrow stromal cells (BMSCs) as a cellular therapy to modulate immune responses in patients suffering from various inflammatory conditions. A deeper understanding of the molecular mechanisms involved in this modulatory effect could help us design better, more effective protocols to treat immune mediated diseases. In this study, we demonstrated that human BMSCs express H1, H2, and H4 histamine receptors and they respond to histamine stimulation with an increased interleukin 6 (IL-6) production both in vitro and in vivo. Using different receptor antagonists, we pinpointed the importance of the H1 histamine receptor, while Western blot analysis and application of various mitogen-activated protein kinase inhibitors highlighted the role of p38, extracellular signal-regulated kinase, and c-Jun N-terminal kinase kinases in the observed effect. When BMSCs were pretreated with either histamine or degranulated human mast cells, they exhibited an enhanced IL-6-dependent antiapoptotic effect on neutrophil granulocytes. Based on these observations, it is likely that introduction of BMSCs into a histamine-rich environment (such as any allergic setting) or pretreatment of these cells with synthetic histamine could have a significant modulatory effect on the therapeutic potential of BMSCs.

An approach to urticaria in the elderly patients

The guidelines for the management of urticaria in adults and children have been published in outstanding position papers. By contrast, the onset of urticaria in the elderly has not yet had a clear definition. In order to approach diagnosis and treatment in a population of elderly patients, we have performed an epidemiological study on a population of elderly people observed in the Immuno Allergology Unit in Bari University Hospital. The patients underwent skin prick test for food allergy and laboratory and instrumental tests. From the data it resulted that 49% of cases have had urticaria because of adverse drug reactions (ADRs), 16% of cases were positive to food, while in 21% of cases systemic and metabolic diseases (SMDs) have been diagnosed. If we consider the young controls, urticaria for ADR was present in 48% of cases; however, in 28% it was possible to make the diagnosis of food allergy, 12% cases had a SMD. Our results show that the main cause of urticaria in the elderly is related to drug assumption because of the high number of drugs taken, followed by internal pathologies correlated to the typical immune and metabolic changes of the elderly. Furthermore, from the observation of our data it was possible to give guidelines for the treatment of urticaria in geriatric age.

The employment of leukotriene antagonists in cutaneous diseases belonging to allergological field

Leukotrienes (LTs) are potent biological proinflammatory mediators. LTC4, LTD4, and LTE4 are more frequently involved in chronic inflammatory responses and exert their actions binding to a cysteinyl-LT 1 (CysLT1) receptor and a cysteinyl-LT 2 (CysLT2) receptor. LTs receptor antagonists available for clinical use demonstrate high-affinity binding to the CysLT1 receptor. In this paper the employment of anti-LTs in allergic cutaneous diseases is analyzed showing that several studies have recently reported a beneficial effects of these agents (montelukast and zafirlukast as well as zileuton) for the treatment of some allergic cutaneous related diseases-like chronic urticaria and atopic eczema although their proper application remains to be established.

A review of the efficacy of desloratadine, fexofenadine, and levocetirizine in the treatment of nasal congestion in patients with allergic rhinitis

BACKGROUND

Nasal congestion is the most troublesome symptom of allergic rhinitis (AR). First-generation and older second-generation antihistamines, while effective against nasal itching, sneezing, and rhinorrhea, have limited efficacy in relieving nasal congestion.

OBJECTIVE

This review included nasal challenge studies and clinical trials that reported the effects on nasal congestion of the newer second-generation antihistamines desloratadine, fexofenadine, and levocetirizine.

METHODS

MEDLINE and EMBASE were searched for nasal challenge studies and clinical trials published in English between January 1, 1991, and January 31, 2009, using the following terms, alone or in combination: antihistamines, second-generation antihistamines, allergic rhinitis, intermittent allergic rhinitis, perennial allergic rhinitis, persistent allergic rhinitis, seasonal allergic rhinitis, nasal challenge, nasal blockage, and nasal congestion. Studies that were not active or placebo controlled, that did not evaluate change in nasal congestion scores, or that focused on treatments other than desloratadine, fexofenadine, and levocetirizine for nasal congestion associated with AR were excluded.

RESULTS

Twenty-six clinical trials met the criteria for inclusion in the review. In 11 placebo-controlled trials that included objective assessment of nasal congestion, desloratadine, fexofenadine, and levocetirizine were associated with reductions in the severity of nasal congestion through maintenance of nasal airflow. The mean AUC for nasal airflow over 6 hours was significantly greater with desloratadine compared with placebo in 3 studies (P < 0.05); placebo-controlled trials of fexofenadine and levocetirizine had similar results. In 25 placebo- and active-controlled trials that reported subject-rated symptom scores, the 3 newer antihistamines were efficacious in the treatment of nasal congestion associated with AR. In 10 trials that reported objective and/or subjective measures, desloratadine was associated with significant improvements in nasal congestion compared with placebo (P < or = 0.05), beginning as early as the first 2 hours after allergen challenge. Fexofenadine was associated with significantly lower nasal congestion scores compared with placebo in 4 studies (P <- 0.05); nasal congestion scores were significantly reduced with levocetirizine in 3 placebo-controlled trials (P < or = 0.005).

CONCLUSIONS

In the studies reviewed, desloratadine, fexofenadine, and levocetirizine were effective in relieving the nasal congestion associated with AR compared with placebo. This effect began as early as day 2 and was consistent and progressive throughout treatment. Desloratadine, fexofenadine, and levocetirizine are appropriate options for the treatment of nasal congestion in patients with AR.