RESUMO
Aim: pancreatic islets encapsulation is an alternative for using the immuno-suppression to prevent rejection. We used the amniotic membrane as a macro-capsulation. The main objective was to assess the re-vascularization of the allogenic amniotic membrane macro capsule in different sites to ensure the islet viability when using it for encapsulation
Methods: 30 amniotic membranes macro capsules were implanted in 15 dogs in two different sites; in the sub-deltoid shoulder region and in a piggy bag pouch in the recipient peritoneal cavity under general anesthesia. The capsules are removed after day 1, 3, 7, 10, 15, 21, 30 and 60 days. All the capsules are subjected to histo-pathological examination and immuno-histochemistry for neo-vascularization using VEGF, Factor VIII and CD4, CD8 for detection of rejection
Results: all specimens showed inflammation and congested blood vessels with no thrombosis or rejection. VEGF expression and Factor VIII were increased; neo-vascularization associated with vascular invasion but no inflammatory cells of acute rejection. CD4 and CD8 showed mild rejection
Conclusion: the implantation of the amniotic sac macro capsule was fixed nicely within the omental tissue and the sub-deltoid region with minimal or no sign of rejection. Our results should help the clinical application of using this capsule as an immuno-isolator for pancreatic islets transplantation