title: Superimposed pressure oscillations: An alternative to treat airway hyperresponsiveness in an acute sensitized airways mouse model.
abstract: The main driving mechanism during an asthma attack is the hyper-constrictions of airway smooth muscle (ASM), which reduces the airway lumen and makes normal breathing difficult. In spite of some noticeable side effects, bronchodilator drugs such as salbutamol are used to alleviate these symptoms by inducing temporary relaxation of the contracted ASM. In vitro studies have shown that mechanical oscillation can induce relaxation in isolated contracted ASM obtained from healthy subjects but not from asthmatics. To date, little is known about in vivo ASM behaviours, in particular in asthmatic subjects. This in vivo study aims at determining the effect of various superimposed pressure oscillation (SIPO) patterns (different to those occurring during normal breathing) on sensitized airways during an ACh challenge (mimicking an asthmatic attack) and comparing it with the effect of a widely studied broncho-relaxant drug, Isoproterenol (ISO). The study shows that superimposed pressure oscillation in the range of 5-15Hz induces approximately 50% relaxation on pre-constricted sensitized airways in vivo; however, this behaviour was not observed at 20Hz. Our finding suggests that mechanical oscillation, particularly SIPO, may act as a bronchodilator and achieve ASM relaxation.
authors.affiliation: Institute of Biomedical Technologies, Auckland University of Technology, Auckland, New Zealand.
authors.forename: M J
authors.initials: MJ
authors.lastname: Jo-Avila
authors.affiliation: Institute of Biomedical Technologies, Auckland University of Technology, Auckland, New Zealand. Electronic address: ahmed.al-jumaily@aut.ac.nz.
authors.forename: A M
authors.initials: AM
authors.lastname: Al-Jumaily
mesh_terms: D000109:Acetylcholine / Q000627:therapeutic use; D000208:Acute Disease; D000818:Animals; D001993:Bronchodilator Agents / Q000627:therapeutic use; D004195:Disease Models, Animal; D005260:Female; D007545:Isoproterenol / Q000627:therapeutic use; D051379:Mice; D008807:Mice, Inbred BALB C; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D010047:Ovalbumin / Q000633:toxicity; D010991:Plethysmography; D011312:Pressure; D012121:Respiration, Artificial / Q000379:methods*; D012130:Respiratory Hypersensitivity / Q000139:chemically induced / Q000276:immunology / Q000628:therapy*; D012137:Respiratory System / Q000187:drug effects; D013990:Tidal Volume / Q000502:physiology; D014665:Vasodilator Agents / Q000627:therapeutic use
chemical_list: D001993:Bronchodilator Agents; D014665:Vasodilator Agents; D010047:Ovalbumin; D007545:Isoproterenol; D000109:Acetylcholine
keywords: Acute model; Alternative treatment; Asthma; Hyperresponsiveness; Mouse model; Pressure oscillations; Sensitized airways; Superimposed oscillation