Biological and proteomic characterization of a composite mesh for abdominal wall hernia treatment: Reference Study

Laparoscopy for the Treatment of Congenital Hernia: Use of Surgical Meshes and Mesenchymal Stem Cells in a Clinically Relevant Animal Model

More than a century has passed since the first surgical mesh for hernia repair was developed, and, to date, this is still the most widely used method despite the great number of complications it poses. The purpose of this study was to combine stem cell therapy and laparoscopy for the treatment of congenital hernia in a swine animal model. Porcine bone marrow-derived mesenchymal stem cells (MSCs) were seeded on polypropylene surgical meshes using a fibrin sealant solution as a vehicle. Meshes with (cell group) or without (control group) MSCs were implanted through laparoscopy in Large White pigs with congenital abdominal hernia after the approximation of hernia borders (implantation day). A successive laparoscopic biopsy of the mesh and its surrounding tissues was performed a week after implantation, and surgical meshes were excised a month after implantation. Ultrasonography was used to measure hernia sizes. Flow cytometry, histological, and gene expression analyses of the biopsy and necropsy samples were performed. The fibrin sealant solution was easy to prepare and preserved the viability of MSCs in the surgical meshes. Ultrasonography demonstrated a significant reduction in hernia size 1 week after implantation in the cell group relative to that on the day of implantation (p < 0.05). Flow cytometry of the mesh-infiltrated cells showed a non-significant increase of M2 macrophages when the cell group was compared with the control group 1 week after implantation. A significant decrease in the gene expression of VEGF and a significant increase in TNF expression were determined in the cell group 1 month after implantation compared with gene expressions in the control group (p < 0.05). Here, we propose an easy and feasible method to combine stem cell therapy and minimally invasive surgical techniques for hernia repair. In this study, stem cell therapy did not show a great immunomodulatory or regenerative effect in overcoming hernia-related complications. However, our clinically relevant animal model with congenital hernia closely resembles the clinical human condition. Further studies should be focused on this valuable animal model to evaluate stem cell therapies in hernia surgery.

Integration of Biomechanical and Biological Characterization in the Development of Porous Poly(caprolactone)-Based Membranes for Abdominal Wall Hernia Treatment

Aims. Synthetic meshes are the long-standing choice for the clinical treatment of abdominal wall hernias: the associated long-term complications have stimulated the development of a new generation of bioresorbable prostheses. In this work, polycaprolactone (PCL) porous membranes prepared by solvent casting/porogen leaching of PCL/poly(ethylene glycol) (PEG) blends with different compositions (different PCL/PEG weight ratios and PEG molecular weights) were investigated to be applied in the field. An optimal porous membrane structure was selected based on the evaluation of physicochemical, biomechanical, and in vitro biological properties, compared to a reference commercially available hernia mesh (CMC). Findings. Selected PCL7-2i membranes, derived from PCL/PEG 70/30 (PCL: Mw 70,000-90,000 Da; PEG: 35,000 Da), showed suitable pore size for the application, intermediate surface hydrophilicity, and biomimetic mechanical properties. In vitro cell tests performed on PCL7-2i membranes showed their cytocompatibility, high cell growth during 21 days, a reduced production of proinflammatory IL-6 with respect to CMC, and a significant secretion of collagen type I. Conclusions. PCL7-2i membranes showed biomimetic biomechanical properties and in vitro biological properties similar to or even better than - in the case of anti-inflammatory behavior and collagen production - CMC, a commercially available product, suggesting potentially improved integration in the host tissue.