Inducing and inhibitory effects of amniotic membrane on angiogenesis in an animal model

Abstract

Background and purpose: Amniotic membrane (AM), the nearest layer of placenta to the fetus, has two surfaces of epithelial and mesenchymal. The AM contains both angiogenic and anti-angiogenic factors which would result in inducing or inhibition of angiogenesis. Also, there are controversial reports on angiogenesis of the AM. We hypothesized here that angiogenic or anti-angiogenic characteristic of the AM could be depending on the surface. So, the aim of this study was to evaluate surface-dependent angiogenesis of the AM. Materials and methods: Human placenta was obtained shortly after elective Cesarean. Amniotic membrane was separated from the placenta by peeling. The AM was transplanted by dorsal skinfold chamber. Microinvital microscopy was performed one week after transplantation of the AM. Analysis of data was performed using one-way analysis and post-Tukey test in ANOVA. Results: Mesenchymal surface of the AM increased the number of vessel sprouts and their lengths in comparison to control group. Epithelial surface of the AM notably decreased the angiogenesis. Although the number of branch points did not decrease in comparison to control group, their lengths decreased significantly compared with control and epithelial side up groups. Conclusion: These results demonstrate that the AM surface-dependently promotes or inhibits angiogenesis, probably owing to possessing angiogenic or anti-angiogenic factors. Inducing or inhibition of angiogenesis by the AM can be a beneficial therapeutic approach in ischemic diseases or cancer, respectively.