I have been casually tracking stem cell research over the years, especially for neurological indications, primarily to have a feel for where we are in the course of research. It takes years to develop a new therapy, and stem cell therapy is a tricky new technology. Right now we are in the post-hype era – the peak of media hype seems to have passed (probably just a short-attention-span effect) while the hard research continues to grind along. We are also in the snake-oil phase where heartless con-artists are capitalizing on the premature hype to sell fake stem cell treatments to desperate patients.

Meanwhile I want to know how the real research is progressing. It seems we are mostly in the animal trial phase and at the cusp of human trials for the most plausible applications. We may see human applications within 5 years for some applications. Heart failure and macular degeneration, for example, seem to be closest.

Some neurological applications are likely to also be among the early applications. Those applications which are likely to cross the finish line of routine clinical use are those in which we simply need to squirt stem cells into some tissue or body cavity and then the stem cells will function as raw material for regeneration or healing. Heart cells work well because they normally will start beating in time along with their fellow heart cells.

Brain applications are plausible because the brain has native stem cells waiting to be recruited in order to make new pathways, either when learning something fairly new or in response to injury. In other words, there is already a mechanism for recruiting stem cells into the recovery process. Adding more stem cells to the mix might therefore be an easy way add raw material and increase the self-healing process.

That is exactly what a new study is looking at. Researchers Martin Meuller et. al. were interested in studying infantile encephalopathy, brain damage in premature infants that results from lack of oxygen (hypoxia) and inflammation. They created a rat model of this damage by infecting young rats’ brains with E. coli (for the inflammation) and tying off one carotid artery to create lack of blood flow. In one group of rats they then  injected placentaderived mesenchymal stem cells (MSC) into one lateral ventricle (a fluid-filled cavity in the brain), and in a second treatment group they also have a hormone called erythropoietin which stimulates blood stem cells. The study is described as “sham controlled”, but only the abstract is currently available and so I do not have more details on the methodology.

The results were encouraging. They found that 22/23 rats survived the procedure (that’s a good start) and that the MSC survived and started to migrate into the brain tissue. There was also some indication of a therapeutic effect – those rats who received the stem cells improved more after the induced injury.

This is still preliminary animal data and a long way away from human trials or routine clinical use. This can probably best be described as a proof of concept trial – we can inject these kinds of stem cells into brains, they will survive, they appear to get into the brain where they are recruited to help recovery, there does not appear to be any major unanticipated complication, and erythropoietin seems to help. We need to learn as much as we can about this procedure from animal studies before it would be ethical to try it out in humans, and the first human subjects are definitely going to be “guinea pigs”. But this is an encouraging step.

The target population, premature infants, also is a highly plausible one, in that young brains are still in the process of developing and have tremendous potential to repair or compensate for damage. Infants with this kind of brain injury, however, tend (25-50%) to have motor, cognitive, and social deficits. Reducing these deficits would have a huge impact on their quality of life in addition to reducing their lifetime healthcare costs. The potential for benefit is therefore very high in this group.

The pace of this kind of research can seem agonizingly slow. Most published studies are baby steps, inching us a bit closer to the ultimate goal of a new and powerful therapy. The research is grinding forward, however, and results continue to be mostly encouraging. I do hope that within my career I will be routinely ordering stem cell infusions for patients with strokes, dementia, Parkinson’s disease, ALS, and a long list of other neurological diseases that we can currently manage but not cure. We just can’t predict the future course of research, however. We can extrapolate current trends, but the unknown elements of research often seem to change the game on us unexpectedly (sometimes for better, often for worse). After the fact progress always seems inevitable. There is a sense of inevitability with stem cell treatments – I hope it is warranted. The hard part is being patient, waiting, and watching.

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