Upregulation of Surfactant Protein A in Chronic Rhinosinusitis

Abstract

Surfactant protein A (SP-A) is protein that appears to play an important role in mammalian first-line host defense. However, the presence of SP-A in the human paranasal sinus mucosa is not well known. The purpose of this study was to investigate the expression of SP-A protein in human paranasal sinus mucosa and to compare the expression of SP-A mRNA between normal paranasal sinus mucosa and paranasal sinus mucosa with chronic rhinosinusitis. Paranasal sinus mucosa samples from 10 patients who underwent surgery for chronic rhinosinusitis without polyps and 10 normal control subjects were used. Reverse transcriptase polymerase chain reaction was done to detect SP-A mRNA. The expression level of SP-A transcripts was semiquantified with desitometry. Cellular localization of SP-A was sought by using immunohistochemistry. SP-A mRNA and protein were expressed in the human paranasal sinus mucosa. SP-A/GAPDH mRNA ratio in the paranasal sinus mucosa with chronic rhinosinusitis was greater compared with that in normal paranasal sinus mucosa (P<.05). Immunohistochemical staining revealed SP-A immunoreactivity in the epithelial cells and submucosal glands of paranasal sinus mucosa in both control subjects and chronic sinusitis patients. Stronger immunoreactivity was observed in chronic rhinosinusitis mucosa as compared with normal paranasal sinus mucosa. SP-A mRNA and protein are present in both normal and diseased human paranasal sinus mucosa. These results may provide potential targets for novel therapy of chronic rhinosinusitis.