Nasal hyperosmolar challenge with a dry powder of mannitol in patients with allergic rhinitis. Evidence for epithelial cell involvement.
BACKGROUND
The responses to airway hyperosmolar challenges probably involve various inflammatory mediators. However, it is not fully understood which cell type/types are the source of these mediators. Potential cell types include mast cell, epithelial cell and the sensory c-fibre nerve cell.


OBJECTIVE
To clarify which cell types are involved with the mediator response to hyperosmolarity in the human airway.


METHODS
Ten healthy subjects, 11 patients with nonactive allergic rhinitis, and nine with active allergic rhinitis were challenged intranasally with mannitol powder, and with sham provocation, on separate days. Symptoms were assessed by visual analogue scales and nasal patency by measuring the nasal peak inspiratory flow (nPIF). Nasal lavage fluid levels of alpha(2)-macroglobulin (an index of plasma extravasation), substance P (an index of sensory nerve cell activation), tryptase (an index of mast cell activation) and 15-hydroxyeicosatetraenoic acid (15-HETE, an index of epithelial cell activation) were analysed.


RESULTS
Immediate, although transient burning was the most prominent symptom in all groups whereas only the patients with active rhinitis experienced a fall in nPIF. Mannitol significantly increased the nasal lavage fluid 15-HETE levels in the allergic patients (P < 0.01 vs the sham challenge), but not in the healthy subjects. The increase in 15-HETE correlated with nasal symptoms for itching (r(s) = 0.65, P = 0.019) and burning (r(s) = 0.72, P = 0.009). Detectable levels of tryptase was found only in five allergic subjects. Lavage levels of substance P and alpha(2)-macroglobulin did not not change.


CONCLUSIONS
Epithelial cell seems to be involved with the mediator response to airway hyperosmolar challenge. The roles of sensory c-fibre nerve cell and mast cell remained less clear.
Koskela
H
H
Department of Respiratory Medicine, Kuopio University Hospital, 70211 Kuopio, Finland.
Di Sciascio
M B
MB
Anderson
S D
SD
Andersson
M
M
Chan
H K
HK
Gadalla
S
S
Katelaris
C
C
D000328:Adult; D004847:Epithelial Cells / Q000187:drug effects / Q000276:immunology; D005260:Female; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism; D006982:Hypertonic Solutions / Q000008:administration & dosage*; D007320:Inspiratory Capacity; D008297:Male; D008353:Mannitol / Q000008:administration & dosage*; D008407:Mast Cells / Q000276:immunology; D017817:Nasal Lavage Fluid / Q000276:immunology; D009297:Nasal Mucosa / Q000187:drug effects / Q000276:immunology*; D009299:Nasal Provocation Tests; D009412:Nerve Fibers / Q000276:immunology; D011208:Powders; D012221:Rhinitis, Allergic, Perennial / Q000276:immunology* / Q000503:physiopathology; D012697:Serine Endopeptidases / Q000378:metabolism; D012912:Sneezing; D013147:Spirometry; D013373:Substance P / Q000378:metabolism; D053802:Tryptases; D000511:alpha-Macroglobulins / Q000378:metabolism
D006893:Hydroxyeicosatetraenoic Acids; D006982:Hypertonic Solutions; D011208:Powders; D000511:alpha-Macroglobulins; D013373:Substance P; D008353:Mannitol; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid; D012697:Serine Endopeptidases; D053802:Tryptases