STIMULATION OF DISPERSED NASAL POLYP CELLS BY HYPEROSMOLAR SOLUTIONS (REPRINTED FROM J ALLERGY CLIN IMMUNOL, VOL 96, PG 980-5, 1995)

It has been suggested that hyperosmolarity may be one of the stimuli t hat provoke exercise-induced asthma and rhinitis. We investigated whet her changes in osmolarity could result in increased levels of mediator release from nasal cells. Cells were dispersed from nasal polyps by e nzymatic digestion and were incubated for 15 minutes with solutions of varying osmolarity obtained by the addition of mannitol to Hanks' bal anced salt solution. After incubation was performed cell supernatants were removed and the release of 15-hydroxyeicosatetraenoic acid, prost aglandin, leukotriene B-4, and fibronectin was measured. Lactate dehyd rogenase was measured to assess cell viability. Epithelial cells made up 40% to 60% of cells and mononuclear cells 40% to 65%. At 900 mOsm/k g H2O, which has been suggested as the osmolarity of the fluid lining the airways during exercise we observed a significant increase (Wilcox on W test) in the release of 15-hydroxyeicosatetraenoic acid (p < 0.00 8), leukotriene B-4 (p < 0.008), and prostaglandin(2) (p < 0.008), but no significant increase in the release of Fibronectin was seen. No si gnificant increase was seen between lactate dehydrogenase and 15-hydro xyeicosatetraenoic acid release, suggesting that the increase in media tor levels was not caused by cell death. These results show that hyper osmolar solutions can induce activation of nasal cells, which may at l east partly explain rhinitis caused by exercise.