In a previous post we discussed statements stem cell scientist Alan Trounson about the use of bone marrow-derived mesenchymal stem cells as a treatment for spinal cord injuries. In this post, we will examine other statements he makes about umbilical cord stem cells as treatments for spinal cord injury.
Trounson also writes earlier in the same article: “Studies involving umbilical cord blood for neurological indications have been promoted as a result of preclinical data on the apparent formation of neurons in vitro but there is little evidence of their transdifferentiation to functional neurons or glial cells in vivo.”
This statement, like the one about bone marrow-derived mesenchymal stem cells, is misleading. First of all, umbilical cord blood contains a wide variety of cell types and stem cells. There is a blood-making stem cell in cord blood, and there are also mesenchymal stem cells, unrestricted somatic cells, and neural stem cells. Furthermore, there is no evidence that embryonic stem cells form neurons in the spinal cord of human patients either. Therefore, Trounson is setting a standard for umbilical stem cells that even embryonic stem cells cannot yet meet. The real question is does administration of umbilical cord stem cells help patients with neurological conditions.
Can umbilical cord stem cells form neurons in culture? The answer is a clear yes. Buzanska and colleagues established the existence of a neural stem cell population in umbilical cord blood. They expanded a population of neural stem/progenitor cells selected from the non-blood-making fraction of umbilical cord blood. From this fraction, they established a human umbilical cord blood neural stem-like cell (HUCB-NSC) line. They treated the cells with serum and a chemical called dBcAMP to make them form neurons. Upon treatments, the HUCB-NSC cells expressed many functional proteins for a variety of different types of neurons, and also showed the types electrophysiological characteristics of neurons. This definitively showed that cord blood-derived progenitors could be effectively differentiated into functional neuron-like cells in vitro (Buzanska et al., Neurodegener Dis. 2006;3(1-2):19-26).
Buzanska’s data is significant because most of the time when umbilical cord blood stem cells are used in experiments, a mixed population is used that consists of a few neural-progenitor cells and many other type of progenitor cells. Therefore, the failure of umbilical cord stem cells to form neuron in vivo is not an indication of the failure of the specific neural progenitor population to form neurons. Rather it is an indication that the small population of neural progenitor cells was unable to form enough detectable neurons for the experiment in question.
Secondly, Trounson states that there is little evidence of the differentiation of cells to neurons or glia in vivo. However, an experiment by Lim and his colleagues have shown that this is not the case. Lim and coworkers administered human umbilical cord mesenchymal stem cells (MSCs) into the spinal cord by means of lumbar puncture and intravenously into the tail vein of rats that had suffered a stroke. The cells were transplanted 3 days after the stroke, and the rats were tested one week, two weeks, three weeks, and four weeks after the stroke. Rat brains were also examined one week after the administration of the umbilical cord stem cells. That rats that had received hUCB-MSCs by means of lumbar puncture had significantly more cells in the damaged areas of the brain than those rats that had received cells intravenously. Also, many of the cells administered by means of lumbar puncture expressed genes specific to neurons and astrocytes. Animals that received hUCB-MSCs also showed significantly improved motor function and reduced ischemic damage when compared with untreated control animals. This is good evidence that umbilical stem cells can form neurons in vivo, which is in direct contradiction to Trounson’s assertion (Lim JY, et al., Stem Cell Res Ther. 2011 Sep 22;2(5):38).
Additionally, administration of umbilical cord cells can help patients with neurological diseases even though they may not differentiate into neurons in the spinal cords of patients. For instance, several stroke patients have shown improvement after administration of umbilical cord stem cells (Harris DT, Stem Cell Rev. 2008 Dec;4(4):269-74). Therefore, umbilical cord stem cells have therapeutic potential for neurological conditions, that is, as yet, untapped, and deprecating them does patients no good at all.
Remember that Trounson is receiving lots of taxpayer money for his California Stem Cell Institute. This institute is pushing embryo-destructive research on the public by using taxpayer dollars. Therefore, it is necessary for him to make somatic stem cells look as paltry as possible and push embryonic stem cells into as positive light as possible, However, the huge amount of money simply cannot be justified and neither can the wanton destruction of human life. Trounson has overstated the vase of embryonic stem cells and understated the case for adult and umbilical stem cells. It is simple politics and not science.