Anti-Inflammatory and Anti-Fibrotic Effects of Human Amniotic Membrane Mesenchymal Stem Cells and Their Potential in Corneal Repair.

Acute ocular chemical burns are ophthalmic emergencies requiring immediate diagnosis and treatment as they may lead to permanent impairment of vision. The clinical manifestations of such burns are produced by exacerbated innate immune response via the infiltration of inflammatory cells and activation of stromal fibroblasts. New therapies are emerging that are dedicated to repair mechanisms that improve the ocular surface after damage; for example, transplantation of stem cells (SC) has been successfully reported for this purpose. The pursuit of easily accessible, noninvasive procedures to obtain SC has led researchers to focus on human tissues such as amniotic membrane. Human amniotic mesenchymal SC (hAM-MSC) inhibits proinflammatory and fibrotic processes in different diseases. hAM-MSC expresses low levels of classical MHC-I and they do not express MHC-II, making them suitable for regenerative medicine. The aim of this study was to evaluate the effect of intracameral injection of hAM-MSC on the clinical manifestations, the infiltration of inflammatory cells, and the activation of stromal fibroblasts in a corneal alkali-burn model. We also determined the in vitro effect of hAM-MSC conditioned medium (CM) on α-SMA+ human limbal myofibroblast (HLM) frequency and on release of neutrophil extracellular traps (NETs). Our results show that intracameral hAM-MSC injection reduces neovascularization, opacity, stromal inflammatory cell infiltrate, and stromal α-SMA+ cells in our model. Moreover, in in vitro assays, CM from hAM-MSC decreased the quantity of α-SMA+ HLM and the release of NETs. These results suggest that intracameral hAM-MSC injection induces an anti-inflammatory and anti-fibrotic environment that promotes corneal wound healing. Stem Cells Translational Medicine 2018;7:906-917.

Ophthalmic indications of amniotic membrane transplantation in Mexico: an eight years Amniotic Membrane Bank experience.

Amniotic membrane, the inner layer of the placenta, has biological properties (e.g. promotes epithelization, reduces fibrosis, secretes antimicrobial products and inhibits immune responses) which make it a useful option for several ophthalmologic procedures, especially those involving the ocular surface. Its use in eye surgery has been reported by other authors. To our knowledge, there is a lack of descriptive studies on surgical indications using amniotic membrane in Mexican population. Here we describe the eight years Amniotic Membrane Bank experience in Mexico, including a detailed protocol of the donors selection, tissue harvesting, preparation, storage and distribution of amniotic membrane since its establishment in 2007. Moreover, we describe the Ophthalmological indications of amniotic membrane transplantation of the total of 1686 amniotic membranes fragments used during eight years. The five most common indications for amniotic membrane transplantation were pterygium (46 %), corneal ulcers (12.6 %), conjunctival surface repair (11.1 %), neoplasms (7.4 %), and persistent epithelial defects (7.3 %). In addition, we compared the indications of amniotic membrane use in two different types of Institutions: general hospitals and ophthalmologic reference hospitals. We found interesting differences between the indications and use rates between these institutions, although pterygium was the most frequent pathology that amniotic membrane fragments were used in both institutions, there was up to a five-fold increase in the use of amniotic membrane for correction of persistent epithelial defects in reference hospitals which could be explained due to the more complex and severe ophthalmological pathologies admitted in reference hospitals. In conclusion, Amniotic Membrane is used in a numerous ocular pathologies and especially on pterygium in our Mexican population.