Research Article: Behavior of Transplanted Multipotent Cells after in Vitro Transplantation into the Damaged Retina

Date Published: , 2011

Publisher: A.I. Gordeyev

Author(s): S.A. Sergeev, Y.V. Khramova, M.L Semenova, I.N. Saburina, N.V. Kosheleva.



The use of stem cell technologies in retinal defect reparation therapy has
produced beneficial results. Nowadays, numerous protocols exist which provide a
neural differentiation of the stem cells transplanted into the retina. However,
questions concerning the functional replacement of the missing retinal neurons
by transplanted cells thus far remain unanswered. The organotypic culture
protocol was used in this study in order to prove the possibility of
transdifferentiation of bone marrow stromal cells (MMSCs) and neural
stem/progenitor cells (NSPCs) from EGFP-positive mice and the functional
integration of these cells. This technique enables a detailed characterization
of cell behavior post-transplantation. Using atomic force microscopy, we
reliably demonstrated the difference (p < 0.01) between the thickness of the outgrowths formed by glial and endothelial retina cells and the thickness of neurites and neuro-like transplanted MMSC outgrowths. MMSCs are also shown to form synapses up to 2.5 ± 0.06 µm in diameter on day 4 after the transplantation. Following electrical stimulation (20V, 0.5Hz, 200ms), clear depolarization of retinal neurons and their outgrowths is detected. It is shown that some of these GFP+ MMSCs, which changed their morphology after the transplantation in retinal explants to neuro-like MMSCs, are capable of depolarizing after exogenous stimulation.

Partial Text

Retinal changes caused by various exogenous damaging factors often lead to a partial
or total loss of vision. In order to provide efficient therapy for retinal
pathologies it is necessary to understand the processes involved in the emergence
and progression of these pathologies, as well as the processes leading to retinal
reparation. Methods for the transplantation of cells of wide differentiation
potential – neural stem/progenitor cells (NSPCs) or bone marrow-derived
mesenchymal stem cells (MMSCs) – are currently being developed in order to
curb the progression of irreversible neurodegenerative processes in the retina. It
is believed that, after they are introduced into a recipient’s organism, these
cells not only actively migrate to the damaged site and replace the missing tissue
elements with their differentiated descendants, but that they also secrete a broad
range of trophic and regulatory factors that maintain the functionality of the
damaged tissue and activate its own reparation systems [1].

Obtainment of retinal cultures

Organotypic retinal explant cultures capable of surviving long-term in vitro
were obtained during the first stage of our study. Tissue architectonics
was retained during the entire culturing period (up to 30 days); the major cell
types typical of an intact retina in vivo were present within the
tissue [5] ( Fig. 1 ). Thus, this explant culture is an adequate
model of the developing neuroretina, enabling the retention of the micro-surrounding
neural cells within.

The obtained retinal explant cultures are equivalent to in vivo