An in vitro study on the biocompatibility of fibroblasts in sterile and non-sterile low-cost and commercial meshes.

INTRODUCTION: Despite several successful studies with low-cost meshes (LCM) for the treatment of inguinal hernias in India and Africa, a nationwide application has not been possible for a variety of reasons. One problem is the special preparation and sterilization of these meshes-naturally, they should comply with international standards and demands, which is often difficult to achieve in Africa. Our primary approach was to determine whether there are differences in the biocompatibility of fibroblasts between non-sterile and sterile LCMs and commercial meshes (CM). MATERIALS AND METHODS: Two polyester CMs with different pore size and a polyester LCM were examined as both sterile and non-sterile. LCM was plasma sterilized at 60 °C and steam sterilized at 134 °C. Sterile and non-sterile meshes were soaked with an antibiotic (penicillin/streptomycin) and antimycotic solution (amphotericin B). Human fibroblasts from healthy subcutaneous tissue were used. Various tests for evaluating the growth behavior and cell morphology of human fibroblasts were conducted. Semiquantitative (light microscopy) and qualitative (scanning electron microscopy) analyses were performed after 1 week and again after 12 weeks. The metabolism of fibroblasts was checked by pH measurements and glucose analyses. Biocompatibility of fibroblasts on sterile and non-sterile meshes was carried out by luminescence methods (cell viability and apoptosis) as well as calorimetric methods for proliferation determination (BrDU assay) and cytotoxicity (LDH assay). RESULTS: Light and electron microscopy revealed a moderate growth of fibroblasts on all investigated mesh types. The results of glycolysis and the pH value were within the normal range for all sterile and non-sterile meshes. In biocompatibility studies, no elevated level of apoptosis was detected. The viability measurement of mitochondrial activity of fibroblasts showed a 50% inhibition of mitochondria in all nets, with the exception of non-sterile CM, whereas mitochondrial activity was increased in the non-sterile CM. A proliferation measurement (BrdU test) revealed different growth inhibition in the sterile and non-sterile meshes. This growth inhibition was significantly stronger, particularly for non-sterile CM light meshes, than it was for the non-sterile LCM. CONCLUSION: Again, our studies show no significant differences in biocompatibility of fibroblasts between expensive and low-cost meshes. In addition, we detected fibroblast growth even in sterile meshes, independent of the mesh group. To our knowledge, the present study is the first of its kind in terms of qualitative equivalence of sterile and non-sterile in vitro mesh samples. We do not wish to create future patient studies with non-sterilized meshes saturated with antibiotics/antimycotics. However, perhaps we can prove in future studies that under semi-sterile conditions with certain LCMs, wound infection rates can be acceptable.

In-vitro examination of the biocompatibility of fibroblast cell lines on alloplastic meshes and sterilized polyester mosquito mesh.

INTRODUCTION: The use of alloplastic implants for tissue strengthening when treating hernias is an established therapy worldwide. Despite the high incidence of hernias in Africa and Asia, the implantation of costly mesh netting is not financially feasible. Because of that various investigative groups have examined the use of sterilized mosquito netting. The animal experiments as well as the clinical trials have both shown equivalent short- and long-term results. The goal of this paper is the comparison of biocompatibility of human fibroblasts on the established commercially available nets and on sterilized polyester mosquito mesh over a period of 12 weeks. MATERIALS AND METHODS: Three commercially available plastic mesh types and a gas-sterilized mosquito polyethylenterephtalate (polyester) mesh were examined. Human fibroblasts from subcutaneous healthy tissue were used. Various tests for evaluating the growth behavior and the cell morphology of human fibroblasts were conducted. The semi-quantitative (light microscopy) and qualitative (scanning electron microscopy) analyses were performed after 1 week and then again after 12 weeks. The cell proliferation and cytotoxicity of the implants were investigated with the help of the 5'-bromo-2'-deoxyuridine (BrdU)-cell proliferation test and the LDH-cytotoxicity test. The number of live cells per ml was determined with the Bürker counting chamber. In addition, analyses were made of the cell metabolism (oxidative stress) by measuring the pH value, hydrogen peroxide, and glycolysis. RESULTS: After 12 weeks, a proliferation of fibroblasts on all mesh is documented. No mesh showed a complete apoptosis of the cells. This qualitative observation could be confirmed quantitatively in a biochemical assay by marking the proliferating cells with BrdU. The biochemical analysis brought the proof that the materials used, including the polyester of the mosquito mesh, are not cytotoxic for the fibroblasts. The vitality of the cells was between 94 and 98%. The glucose metabolism as well as the pH value of the fibroblasts showed no significant differences between the tested meshes. The examination of the oxidative stress via measurement of the H2O2 concentration showed values in the normal range for the commercially alloplastic meshes and the mosquito mesh. CONCLUSIONS: Our examination showed no significant difference with regard to biocompatibility between the officially approved and cost-intensive meshes and the sterilized (autoclaved) mosquito mesh. Due to the proven strength and stability of the mosquito mesh and their proven compatibility, the implantation of the sterilized mosquito mesh in additional in vivo studies must be considered. A wide-scale and cost-effective treatment of hernias could thus be guaranteed, not only in Third World countries.