The Histamine 3 Receptor Is Expressed in the Heart and Its Activation Opposes Adverse Cardiac Remodeling in the Angiotensin II Mouse Model

Histamine is a basic amine stored in mast cells, with its release capable of activating one of four histamine receptors. The histamine 3 receptor (H3R) is known to be cardioprotective during acute ischemia by acting to limit norepinephrine release. However, a recent study reported that myofibroblasts isolated from the infarct zone of rat hearts responded to H3R activation by up-regulating collagen production. Thus, it is necessary to clarify the potential role of the H3R in relation to fibrosis in the heart. We identified that the mouse left ventricle (LV) expresses the H3R. Isolation of mouse cardiac fibroblasts determined that while angiotensin II (Ang II) increased levels of the H3R, these cells did not produce excess collagen in response to H3R activation. Using the Ang II mouse model of adverse cardiac remodeling, we found that while H3R blockade had little effect on cardiac fibrosis, activation of the H3R reduced cardiac fibrosis and macrophage infiltration. These findings suggest that when activated, the H3R is anti-inflammatory and anti-fibrotic in the mouse heart and may be a promising target for protecting against cardiac fibrosis.

The combination of loratadine with famotidine to relieve the symptoms of urinary frequency in female patients with bladder function disorders：First report of three cases

WHAT IS KNOWN AND OBJECTIVES

Urinary frequency is a common presentation of bladder function disorders in female patients. Few medicines are effective in all patients. The use of loratadine combined with famotidine had not been previously reported for this indication.

CASE DESCRIPTION

Three female patients complaining of urinary frequency had been given loratadine at 10 mg QD combined with famotidine 20 mg BID for about 5 months. They all achieved symptom improvement.

WHAT IS NEW AND CONCLUSION

The combination of loratadine with famotidine was used to treat urinary frequency. It was safe, effective, and convenient, and may be an option for oral medical therapy in female patients with bladder function disorders.

Observational cohort study: safety outcomes in children using proton pump inhibitors or histamine-2 receptor antagonists

OBJECTIVE

Acid suppression with histamine-2 receptor antagonists (H₂RAs) or proton pump inhibitors (PPIs) is recommended for children with persistent gastroesophageal reflux disease symptoms. In this retrospective, observational postauthorization study, we aimed to assess and compare safety outcomes in pediatric first-time users of esomeprazole, other PPIs or H₂RAs.

METHODS

Data on children (aged 0-18 years) first dispensed esomeprazole, other PPIs or H₂RAs between September 2008 and August 2011 was obtained from the Dutch PHARMO Database Network. Hospitalizations for seven predefined safety outcomes were evaluated (maximum follow-up: 18 months). Rate ratios were calculated using Poisson regression adjusted for baseline imbalances. Discharge letters were reviewed for event occurrence confirmation.

RESULTS

Of 23,470 included children, 2820 (median age: 3 years) were prescribed esomeprazole, 13,818 (median age: 15 years) other PPIs and 6832 (median age: 5 years) H₂RAs. In total, 504 (2%) children were hospitalized for 762 predefined events: gastroenteritis (246); convulsion/seizure (200); pneumonia (154); failure to thrive (119); acute interstitial nephritis (19); thrombocytopenia (23); and angioneurotic edema (1). Significant differences between cohorts were observed only for failure to thrive, with adjusted rate ratios (95% confidence interval) for esomeprazole of 6.1 (2.4-15.7) vs. other PPIs and 6.1 (2.9-12.8) vs. H₂RAs among current users. Occurrence was confirmed for 74% of assessable events. Confirmation rates were highest for pneumonia (81%) and lowest for failure to thrive (40%).

CONCLUSIONS

Hospitalization rates for predefined outcomes were low and mostly similar in pediatric first-time users of PPIs and of H₂RAs.

TRIAL REGISTRATION

NCT01338363.

Effects of histamine and its antagonists on murine T-cells and bone marrow-derived dendritic cells

We determined the effects of histamine and its antagonists on the surface marker expression of dendritic cells (DCs) and the influence of lipopolysaccharide (LPS), histamine, and histamine receptor antagonists on DCs and T-cells. The bone marrow was extracted from the femurs and tibiae of 6- to 8-week-old female Balb/c mice and cultured in medium containing penicillin, streptomycin, L-glutamine, fetal calf serum, or granulocyte macrophage colony-stimulating factor (GM-CSF) alone or with interleukin (IL)-4. The cells received three different doses of LPS and histamine, plus three different doses of descarboethoxyloratadine (DCL). We assayed the supernatant for various cytokines. The spleen cells of DO11.10 mice were examined by flow cytometry, which included labeling and sorting CD4+ T-cells, as well as coculture of DCs and T-cells with ovalbumin (OVA)_323–339 peptide. Histamine or histamine plus DCL did not affect the expression of major histocompatibility complex class II, CD11c, CD11b, CD86, and CD80. However, GM-CSF increased the expression of all markers except CD80. Histamine increased interferon-γ production in GM-CSF + IL-4-cultured cells; it also enhanced IL-10 production, but suppressed IL-12 production in LPS-stimulated DCs with no DCL. Cimetidine inhibited IL-10 production and restored IL-12 secretion in LPS-treated DCs. LPS increased IL-10 and decreased IL-12 levels. GM-CSF + IL-4-generated DCs had a stronger stimulatory effect on DO11.10 T-cell proliferation than GM-CSF-generated DCs. Inducible costimulator ligand expression was higher in GM-CSF + IL-4- than in GM-CSF-generated DC groups after 2 days of coculture, but decreased 4 days later. IL-13 production was higher in bone marrow DCs generated with GM-CSF than in those generated with GM-CSF + IL-4. OVA-pulsed DCs and OVA-plus-DCL DCs showed increased IL-12 levels. OVA plus LPS increased both IL-10 and interferon-α. Although histamine or histamine receptor-1 antagonists did not influence DC LPS-driven maturation, they influenced cytokine production. LPS and GM-CSF influenced surface marker expression and cytokine production.