Abstract
Purpose:
Stem cells (SC) promise to provide a well-characterized and reproducible source for cell replacement therapies. A potential application of this technology could be the treatment of retinal degenerative diseases. Hence this study sought to assess the in vitro differentiation capacity of human bone marrow-derived stem cells (BMSC) towards retinal cell types.
Methods:
Samples of human bone marrow (BM) and mobilized peripheral blood (mPB) were collected from patients with blood cancer and granulocyte colony-stimulating factor (G-CSF) mobilization. Mononuclear cells (MNC) were isolated from the samples using Ficoll-Paque density gradient centrifugation, and were sorted by magnetic activated cell sorting (MACS) for specific BMSC populations. These cells were then cocultured on human RPE for 7 days. Cell morphology as well as expression of stem cell, retinal, and neural specific markers was examined by immunohistochemistry. In addition, the expression profiles of the different BMSC populations were assessed after FACS separation of the cocultured samples by quantitative reverse transcription polymerase chain reaction (qRT-PCR).
Results:
Populations of CD34+CD38+ and CD34+CD38- cells were isolated with 0.63 ± 0.42% and 0.4 ± 0.27% of total PBMNC and 3.38 ± 0.31% and 1.91 ± 2.24% of total BMMNC. After 7 days of co-culture the BMSC adopted an elongated epithelial morphology and immunohistochemistry showed expression of RPE markers such as RPE65 and bestrophin. In addition, RT-qPCR analysis of CD34+CD38- cells showed down-regulation of SC markers (GATA2 and β2M) but also down-regulation of RPE-specific markers (RPE65, BEST and MITF). However, the neural progenitor marker nestin and the early neuronal marker βIII-tubulin were up-regulated. In contrast, the CD34+CD38+ population showed upregulation of SC markers and down-regulation of all other investigated markers.
Conclusions:
Our data demonstrated that human CD34+CD38- BMSC may differentiate towards an RPE-like cell type in vitro and could become a new type of donor cells for regenerative therapy in retinal degenerative diseases.
Keywords: 701 retinal pigment epithelium •
721 stem cells •
695 retinal degenerations: cell biology