Stem Cells Home to Damaged RPE

I have nothing new to report. I do not perceive any further changes, positive or negative, in my vision. I have scheduled an appointment with my ophthalmologist. I am sure that will be a lot of fun (sarcasm). Oh, he is a nice guy. This situation just puts us in adversarial positions, unfortunately. He cannot condone my choices because they are outside the establishment. I cannot follow his advice. So, I guess it is a stalemate.

This situation has peaked my interest in how these cells could penetrate the blood/brain barrier. To my understanding, science considers this blood/brain barrier a major obstacle to treating the retina. Yes, I have spent entirely too much time reading about this stuff. Time that should have been spent learning to tango or enjoying fine wine, I suppose.

Anyway, I digress. I started surfing PubMed looking for stem cell research for retinal degeneration that relied on a systemic approach, meaning the cells were not put in the eye but delivered intraveneously or under the skin.

Granted, this work involves a rat and bone marrow- derived cells. If you are interested, see the abstract below:

Systemically transferred hematopoietic stem cells home to the subretinal space and express RPE-65 in a mouse model of retinal pigment epithelium damage.
Atmaca-Sonmez P,
Li Y,
Yamauchi Y,
Schanie CL,
Ildstad ST,
Kaplan HJ,
Enzmann V.
Department of Ophthalmology & Visual Sciences, University of Louisville, 301 E. Muhammad Ali Blvd., Louisville, KY 40202, USA.
Stem cell regeneration of damaged tissue has recently been reported in many different organs. Since the loss of retinal pigment epithelium (RPE) in the eye is associated with a major cause of visual loss - specifically, age-related macular degeneration - we investigated whether hematopoietic stem cells (HSC) given systemically can home to the damaged subretinal space and express markers of RPE lineage. Green fluorescent protein (GFP) cells of bone marrow origin were used in a sodium iodate (NaIO(3)) model of RPE damage in the mouse. The optimal time for adoptive transfer of bone marrow-derived stem cells relative to the time of injury and the optimal cell type [whole bone marrow, mobilized peripheral blood, HSC, facilitating cells (FC)] were determined by counting the number of GFP(+) cells in whole eye flat mounts. Immunocytochemistry was performed to identify the bone marrow origin of the cells in the RPE using antibodies for CD45, Sca-1, and c-kit, as well as the expression of the RPE-specific marker, RPE-65. The time at which bone marrow-derived cells were adoptively transferred relative to the time of NaIO(3) injection did not significantly influence the number of cells that homed to the subretinal space. At both one and two weeks after intravenous (i.v.) injection, GFP(+) cells of bone marrow origin were observed in the damaged subretinal space, at sites of RPE loss, but not in the normal subretinal space. The combined transplantation of HSC+FC cells appeared to favor the survival of the homed stem cells at two weeks, and RPE-65 was expressed by adoptively transferred HSC by four weeks. We have shown that systemically injected HSC homed to the subretinal space in the presence of RPE damage and that FC promoted survival of these cells. Furthermore, the RPE-specific marker RPE-65 was expressed on adoptively transferred HSC in the denuded areas.
PMID: 16949576 [PubMed - indexed for MEDLINE]