A case of bilateral inguinal hernia recurrence in infancy: Investigations on collagen metabolism

Background. Recurrent inguinal hernias in early infancy are rare. We report on a case of a 3-month-old male infant suffering bilateral inguinal hernia recurrence (RINGH). Due to previous observations of an altered collagen metabolism in hernia patients, a severe connective-tissue pathology in the infant was hypothesised. Methods. Hernial sac tissue of the infant was analysed and compared to specimens from five children operated upon one-sided primary inguinal hernias (controls). In paraffin-embedded sections, we determined the distribution of collagen types I and III by crosspolarisation microscopy and the expression of matrix metalloproteinase 2 (MMP-2) by immunohistochemistry. In fibroblast cultures, expression of collagen types I and III and of MMP-2 was investigated by RT-PCR (real-time polymerase chain reaction) and zymography. Electron microscopical investigations were performed exemplarily in two fibroblast cultures to compare cell morphology. Results. No differences in collagen I/III ratios between RINGH and controls were found either on protein or on mRNA level. Immunohistochemical and RT-PCR analysis of MMP-2 showed a lowered expression in the RINGH patient, as compared to controls, whereas the gelatinolytic activity of MMP-2 did not differ between the groups. Electron microscopical investigations showed similar cell arrangement and morphology. Conclusions. To conclude, a marked biochemical correlate to a severe connective-tissue pathology in the infant suffering inguinal hernia recurrence could not be found. With regard to the slight differences in the expression of MMP-2, a possible role in the genesis of inguinal hernia recurrence cannot be ruled out.