IOBA (Eye Institute) of the University of Valladolid, Valladolid, is considered a reference in Spain in applied research in cell therapy, mainly with allogenic mesemchymal stem cells derived from bone marrow (BM-MSC).

The studies began on the ocular Surface diseases, where clinical trials have been carried out for the treatment of limbal insufficiency, which are the first in the world.(ClinicalTrials.gov Identifier: NCT0388456)

But for the last five years they have also been working on optic nerve pathology. In this field, a phase II clinical trial has been carried out, with five patients affected by acute non-arteritic anterior optic neuropathy. (ClinicalTrials.gov Identifier: NCT03173638)

The results look very promising and a multicenter study is now expected to be completed to recruit more patients. In the meantime, we have found it opportune to review and update all the existing literature, with an eye on the transfer to the clinic, analyzing clinical trials and their safety and efficacy.

The above mentioned review provides an update on the potential of cell therapies to restore or replace damaged and/or lost cells in retinal degenerative and optic nerve diseases. Althought we are concentrated in BM-MSC paper describes the available cell sources and the challenges involved in real clinical practice.

Sources include human fetal stem cells, allogenic cadaveric  stem  cells,  human  CNS  stem  cells,  ciliary  pigmented  epithelial  cells,  limbal  stem  cells,  retinal  progenitor  cells  (RPCs),  human  pluripotent  stem  cells (PSCs) (including both human embryonic stem cells (ESCs) and human induced pluripotent stem cells (iPSCs)) and mesenchymal stem cells (MSCs).

Stem/progenitor cell therapies for retinal diseases still have some drawbacks, such as the inhibition of proliferation and/or differentiation in vitro (with the exception of RPE) and the limited long‐term survival and functioning of grafts in vivo. Some other issues remain to be solved concerning the clinical  translation  of  cell‐based  therapy,  including  (1)  the  ability  to  enrich  for  specific  retinal  subtypes;  (2) cell survival;  (3)  cell delivery, which  may need  to  incorporate a scaffold to induce correct cell polarization, (4) the requirement of complex intraocular surgical techniques wich are potential source of severe complications  (5)  the  evaluation  of  the  risk  of  tumor  formation  caused by  the undifferentiated  stem  cells and prolific  progenitor cells.  For this reason, our group is focused on the use of their paracrine capacities as sources of growth factors, which can be a good alternative to other possibilities of neuroprotection.

Despite the challenges, stem/progenitor  cells  represent  the  most  promising  strategy  for  retinal  and  optic  nerve  disease  treatment  in  the  near  future,  and  therapeutics  assisted  by  gene  techniques,  neuroprotective compounds and artificial devices can be applied to fulfil clinical needs.

This entry is adapted from the peer-reviewed paper 10.3390/pharmaceutics13060865