New generation prosthetic biomaterials for abdominal wall repair have been designed to be less dense, by having larger pores than that of the standard polypropylene meshes, to improve abdominal wall compliance. The aim of the present study was to analyze the functional and morphologic properties of these new meshes. For this purpose, 7 x 5 cm(2) defects were created in the anterior abdominal wall of 36 male New Zealand White rabbits and repaired using different polypropylene meshes: a heavyweight mesh (HW), Surgipro, and two lightweight meshes (LW), Parietene and Optilene. Six animals each implanted with biomaterial were sacrificed on postoperative days 14 and 90. Histological and morphometric analysis, adhesion assessment, and biomechanical resistance tests were performed. Similar behavior was shown by the LW and HW meshes in terms of the adhesions and macrophage response induced. After 14 days, the tensile strength of Optilene was greater than the strengths recorded for the other two biomaterials, probably because of its high elasticity. By 90 days, however, the tensile strengths of the three biomaterials were comparable. In conclusion, despite an initial tensile strength advantage shown by the mesh with larger pores, at 90 days postimplant, tensile strengths were similar. Compared with HW, LW prostheses have the benefit that less foreign material was implanted, preserving the elasticity of the recipient host tissue.

Our findings indicate active MMP-2 upregulation in the abdominal skin of patients with direct inguinal hernia. This metalloproteinase plays a role in matrix degradation, weakening the abdominal wall. Skin disorders and previously described transversalis fascia defects in these patients could point to a systemic collagen metabolism abnormality as a risk factor for direct hernia.

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Biomaterials have long been used to repair defects in the clinical setting, which has led to the development of a wide variety of new materials tailored to specific therapeutic purposes. The efficiency in the repair of the defect and the safety of the different materials employed are determined not only by the nature and structure of their components, but also by the anatomical site where they will be located. Biomaterial implantation into the abdominal cavity in the form of a surgical mesh, such as in the case of abdominal hernia repair, involves the contact between the foreign material and the peritoneum. This review summarizes the different biomaterials currently available in hernia mesh repair and provides insights into a series of peculiarities that must be addressed when designing the optimal mesh to be used in this interface.

Our findings indicate overexpression of the active form of TGFbeta1 in the TF of young patients with direct hernia. This overexpression reflects an attempt to counterbalance the enhanced matrix degradation process observed in these patients, identifying a subset of patients requiring the use of a prosthetic material for primary hernia repair.