Recurrent inguinal hernia: disease of the collagen matrix?

The aim of this study was to investigate the collagen matrix in recurrent inguinal hernias. Total ribonucleic acid (RNA) was extracted from skin fibroblasts of three groups (control group I = healthy skin; control group II = plain skin scar; recurrent inguinal hernia group = skin of recurrent inguinal hernias; each n = 5). Reverse transcription-polymerase chain reaction (RT-PCR) and Northern blot analysis were used to investigate the expression of procollagen type I/- III, MMP-1, and MMP-13 mRNAs. Both ratios of procollagen types I to III mRNAs and collagen types I to III were apparently decreased in the recurrent hernia group compared to those of both control groups (p < 0.01). Significant differences were caused by the increase of both procollagen type III mRNA and collagen type III protein synthesis. A concomitant increase of MMP-1 and MMP-13 mRNAs and proteins was also observed in the recurrent hernia group and showed significant differences compared to those of both control groups I and II, respectively (p < 0.01). In conclusion, the decreased ratio of collagen types I to III seems not only to be the result of a relative increase in the levels of type III procollagen mRNA but also may be the result of an increase of MMP-1 and MMP-13. The data of the present study strongly suggest recurrent inguinal hernias to be a disease of the collagen matrix and result in a clearer understanding of the underlying pathophysiology and may support specific therapeutic strategies in hernia surgery (e.g., surgical meshes).