Background: Elafin is an endogenic serine protease inhibitor that has diverse functions such as anti-inflammation, immunoregulation, anti-microbe and so on. The cause of inflammatory bowel disease (IBD) is still unclear. Recently, the destruction of balance between proteases and antiproteases become the focus in the pathogenisis of IBD. Several studies have reported the expression of elafin in colonic tissue of IBD patients or murine models, although the results are controversial, its therapeutic implication is noteworthy. Here, we detect the expression of elafin in peripheral blood and colonic tissue of IBD patients, then, explore its role and value in assessing the activity and severity of IBD.
Methods: Real-time PCR and ELISA were respectively performed to quantitate elafin mRNA and plasma concentration in a total of 106 peripheral blood samples from 106 patients (41 UC, 27 CD, 38 controls). Compare the expression of elafin between groups and among each stage of IBD. Analyze the correlation between elafin and other markers (ESR, CRP, IBD activity score). Histological inflammation was scored, and elafin was localized and semiquantified by immunohistochemistry in a total of 49 colonic paraffin sections (17 inflamed, 13 noninflamed, 19 controls) from 36 patients (12 UC, 5 CD, 19 controls).
Results: Elafin mRNA levels decreased significantly in active UC group, but increased in remission UC group. However, in CD, we did not detect the above signifcant differences. Moreover, elafin mRNA levels had tendency to decrease with increasing disease severity both in UC and CD. At the same time, elafin plasma concentration decreased both in UC and CD, but the differences among each stage were not signifcant. Extensive expression was detected in the colonic mucosa and gland cells in healthy controls, whereas in UC and CD, both in inflamed and noninflamed tissue, immunostaning of elafin weakened, especially in inflamed mucosa.
Conclusions: The expression of elafin in peripheral blood and colonic inflamed tissue from active IBD patients decreases and correlates with the activity of IBD to some extent, suggesting that it may play a protective role in IBD and may predict disease activity and severity.