Circulating matrix metalloproteinases and procollagen propeptides in inguinal hernia.

PURPOSE: Degradation of collagen has been suggested involved in the pathogenesis of inguinal hernia. In this study, we aim to evaluate circulating biomarkers of procollagen type I N-terminal propeptide (PINP), procollagen type III N-terminal propeptide (PIIINP), matrix metalloproteinases (MMP)-2, MMP-9, copper and zinc in primary and recurrent inguinal hernia patients.
METHODS: This study included 110 inguinal hernia patients: 45 patients had primary indirect inguinal hernia, 40 patients had primary direct inguinal hernia, 15 patients had recurrent indirect inguinal hernia and 10 patients had recurrent direct inguinal hernia. Additional 45 patients operated for reasons other than hernia were included as a control group. All blood samples were obtained preoperatively. Circulating PINP, PIIINP, MMP-2 and MMP-9 were investigated using enzyme-linked immunoabsorbent assay (ELISA) methods, and copper and zinc were measured using an air acetylene flame atomic absorption spectrometer.
RESULTS: Serum MMP-2 levels in patients with direct and recurrent inguinal hernias were significantly higher than controls. The ratios of PINP/PIIINP decreased more apparent in recurrent indirect or direct inguinal hernia group than primary indirect or direct inguinal hernia group. Based on receiver operating characteristic curve analysis, PINP/PIIINP can effectively diagnose recurrent inguinal hernia from primary inguinal hernia with area under the curve (AUC) of 0.919 for recurrent indirect inguinal hernia and 0.808 for recurrent direct inguinal hernia, respectively.
CONCLUSION: The ratio of serum PINP/PIIINP was lower in patients with recurrent inguinal hernia, demonstrating more serious damage of collagen metabolism in these patients. Serologic ratio of PINP/PIIINP may be used to identify the presence of recurrent inguinal hernia in patients.