Matrix metalloproteinases and their inhibitors in the nasal mucosa of patients with perennial allergic rhinitis

Background: Allergic rhinitis and asthma show many similarities in their ep ithelial and inflammatory responses to allergens. However, one notable diff erence is that disruption and desquamation of the epithelium is a character istic feature of asthma, whereas in perennial allergic rhinitis the epithel ium is intact and thickened. One reason for this might be differing express ion of matrix metalloproteinases (MMPs) or their inhibitors (TIMPs). There are few published data on the presence of MMPs or TIMPs in the nasal mucosa in rhinitis. Objective: The purpose of this study was to investigate MMP and TIMP mRNA a nd protein in nasal mucosa from subjects with perennial allergic rhinitis a nd from nonrhinitic control subjects. Methods: Biopsy specimens of nasal mucosa were taken from 10 well-character ized subjects with perennial allergic rhinitis and 10 nonrhinitic control s ubjects. MMP and TIMP mRNA was quantified through use of competitive RT-PCR , and protein was detected by means of Western blotting and ELISA. Results: TIMP-1 mRNA and TIMP-2 mRNA were present in nasal samples, but the re was no significant difference between the 2 groups. Only small amounts o f MMP-1, -2, -3, and -9 mRNA were detected in the same samples. The corresp onding proteins were detected by means of Western blotting. TIMP-1 protein and TIMP-2 protein were quantified in tissue homogenates; there was no sign ificant difference between the 2 groups. Conclusion: Our studies have demonstrated the presence of large amounts of TIMP-1 and TIMP-2 mRNA and protein in nasal mucosa. There is no upregulatio n of MMPs or changes in TIMP expression in the nasal mucosa of patients wit h allergic rhinitis.