Differential regulation of neurotrophin expression in human bronchial smooth muscle cells

BACKGROUND: Human bronchial smooth muscle cells (HBSMC) may regulate airway inflammation by secreting cytokines, chemokines and growth factors. The neurotrophins, including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), have been shown to be elevated during airway inflammation and evoke airway hyperresponsiveness. We studied if HBSMC may be a source of NGF, BDNF and NT-3, and if so, how inflammatory cytokines may influence their production. METHODS: Basal and cytokine (IL-1β, IFN-γ, IL-4)-stimulated neurotrophin expression in HBSMC cultured in vitro was quantified. The mRNA expression was quantified by real-time RT-PCR and the protein secretion into the cell culture medium by ELISA. RESULTS: We observed a constitutive NGF, BDNF and NT-3 expression. IL-1β stimulated a transient increase of NGF, while the increase of BDNF had a later onset and was more sustained. COX-inhibitors (indomethacin and NS-398) markedly decreased IL-1β-stimulated secretion of BDNF, but not IL-1β-stimulated NGF secretion. IFN-γ increased NGF expression, down-regulated BDNF expression and synergistically enhanced IL-1β-stimulated NGF expression. In contrast, IL-4 had no effect on basal NGF and BDNF expression, but decreased IL-1β-stimulated NGF expression. NT-3 was not altered by the tested cytokines. CONCLUSION: Taken together, our data indicate that, in addition to the contractile capacity, HBSMC can express NGF, BDNF and NT-3. The expression of these neurotrophins may be differently regulated by inflammatory cytokines, suggesting a dynamic interplay that might have a potential role in airway inflammation

Maintenance of remission with low-dose olopatadine hydrochloride for itch in well-controlled chronic urticaria

Teruhiko Makino,1 Yoshiaki Takegami,1 Mati Ur Rehman,1 Yoko Yoshihisa,1 Waka Ishida,2 Takashi Toyomoto,3 Tadamichi Shimizu11Department of Dermatology, University of Toyama, Toyama, Japan; 2Department of Dermatology, Niigata Central Hospital, Joetsu, Japan; 3Department of Dermatology, Saiseikai Takaoka Hospital, Takaoka, JapanBackground: The long-term follow-up of chronic urticaria (CU) is important to ensure the adequate treatment of patients. Olopatadine hydrochloride is one of the second-generation nonsedating antihistamines.Methods: This study was designed to assess the optimal dose of olopatadine to suppress symptoms of chronic urticarial itch in well-controlled patients. After CU patients were treated with 10 mg olopatadine, patients having a visual analogue scale (VAS) itch score of less than 20 were randomly allocated into one of three groups: 10 mg/day (n = 35), 5 mg/day (n = 30), or no medication (n = 32).Results: The suppressive effects of both the 5 mg and 10 mg olopatadine treatments on the VAS itch score were more significant and longer lasting over a period of 4 weeks than the no-medication treatment. Both the 5-mg group and the 10-mg group showed improved urticarial symptoms and maintained their VAS itch score within normal limits compared to the no-medication group. The differences between the 5-mg and 10-mg groups were not significant.Conclusion: These results demonstrate that treatment with olopatadine at a dose of 5 mg once daily is effective and safe for the management and prevention of CU symptoms for itch in well-controlled patients.Keywords: chronic urticaria, olopatadine, dose, antihistamine, itch, histamin

Isosmotic modulation of Ca2+-regulated exocytosis in guinea-pig antral mucous cells: role of cell volume

Exocytotic events and changes of cell volume in mucous cells from guinea-pig antrum were examined by video-enhanced optical microscopy.Acetylcholine (ACh) evoked exocytotic events following cell shrinkage, the frequency and extent of which depended on the ACh concentration. ACh actions were mimicked by ionomycin and thapsigargin, and inhibited by Ca2+-free solution and Ca2+ channel blockers (Ni2+, Cd2+ and nifedipine). Application of 100 μM W-7, a calmodulin inhibitor, also inhibited the ACh-induced exocytotic events. These results indicate that ACh actions are mediated by intracellular Ca2+ concentration ([Ca2+]i) in antral mucous cells.The effects of ion channel blockers on exocytotic events and cell shrinkage evoked by ACh were examined. Inhibition of KCl release (quinine, Ba2+, NPPB or KCl solution) suppressed both the exocytotic events and cell shrinkage evoked by ACh.Bumetanide (inhibition of NaCl entry) or Cl−-free solution (increasing Cl− release and inhibition of NaCl entry) evoked exocytotic events following cell shrinkage in unstimulated antral mucous cells and caused further cell shrinkage and increases in the frequency of exocytotic events in ACh-stimulated cells. However, Cl−-free solution did not evoke exocytotic events in unstimulated cells in the absence of extracellular Ca2+, although cell shrinkage occurred.To examine the effects of cell volume on ACh-evoked exocytosis, the cell volume was altered by increasing the extracellular K+ concentration. The results showed that cell shrinkage increases the frequency of ACh-evoked exocytotic events and cell swelling decreases them.Osmotic shrinkage or swelling caused the frequency of ACh-evoked exocytotic events to increase. This suggests that the effects of cell volume on ACh-evoked exocytosis under anisosmotic conditions may not be the same as those under isosmotic conditions.In antral mucous cells, Ca2+-regulated exocytosis is modulated by cell shrinkage under isosmotic conditions