Researchers believe that the therapeutic value of stem cell therapy for brain injury is there, but much important work still needs to be done.
We recently published a couple of papers. One was a followup on some earlier work that I had done at Emory University and Georgia Tech with Doctors Donald Stein and Michelle Laplaca. And in that study we looked at the--kind of--therapeutic window, putting the cells in. Interestingly enough, there is another paper that has come out at the same time by Dr. Dong Sun, and she actually transplanted the cells at the same time points that we did, so we looked at two days post-injury, seven days post-injury, fourteen days post-injury because you want to know--you know--how far out can you go? When can you see an effect? For us, our best time point was seven days post-injury. For them, their best time point was two days post-injury in terms of survival of the cells in the brain after transplantation. So why the difference? They actually transplanted their cells in a completely different area of the brain than we did, and of course we had two different animal models. There's a lot of similarities, but I think that when you--that the location of the transplant can be very key because it has to receive signals from the injured environment in order for the cells to home in, and I know I'm getting off-topic here. Anyway, both of these papers that we had just published, recently published, two papers on stem-cell research, one of which was with animal cells, one of which was with human cells, and in both of these papers, just like all the other papers that I was referring to, the bottom line was that the recovery that we saw--which was substantial; it was significant--was not due to cellular replacement. We didn't see the cells integrating into the brain in terms of--we didn't see cells differentiating into neurons that would replace the lost neurons due to the injury. And the functional recovery occurred too rapidly to be attributed to that, in any case. So what we're doing now is we're taking the media that the cells are cultured in and specifically the media that we're working with is from the human amniotic cells--so it's human amniotic progenitor cell culture medium. We call it ____________. And we're infusing that into animals using an ALZET osmotic mini pump, so it's a little, tiny pump that we implant into the back of an animal, and it has a little tube that we insert into the cerebrum, and over a 2-week period we just continuously pump these trophic factors that are secreted by the cells into the animal. We got very nice beneficial effects just from infusing the animals with the culture media that the stem cells had been cultured in, and we--you know--prior to doing this we showed that we could keep the viability and the bioavailability of the culture intact at body temperature. You know, by different experiments. So--you know--that's kind of proof in principle that's not about, right now, at least, and I'm not saying that cellular replacement couldn't be an avenue in the future. But right now, the bulk of the recovery that we're seeing appears to come predominantly from the beneficial factors that these cells are spitting out, putting out. Well, I hope these kind of results lead to more research on stem cells and traumatic brain injury. And--you know--the therapeutic value, I think, is there. I think this field has not been thoroughly explored and that there is a lot of very, very important work to be done. And so--you know--one would hope very much that it would spark some interest in kind of a--spur on a stem-cell revival, per se, in this area of research. But to do it in a very thoughtful, conservative way, and I think for that to happen, it--really--what we need is to get some of the people together that are interested in doing this, almost form a small consortium. Too often we go off into our own labs after a conference like this, and we just kind of get an idea and we go with it, but I think there's a real strength when you can gather scientists together and they can share ideas and not worry so much about who is going to get credit for what but just really share information freely and share the ideas and be respectful of each others' contributions, and you can really make some powerful advances that way. And that's what I'm hoping we can do with stem cell research as it applies to traumatic brain injury in the future.
Posted on BrainLine October 25, 2011.
Deborah Shear, PhD is the section chief for the in vivo Neuroprotection Labs, Brain Trauma Neuroprotection & Neurorestoration Branch; Center of Excellence for Psychiatry & Neuroscience at the Walter Reed Army Institute of Research (WRAIR) in Silver Spring, MD.
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