Appendix H. 
275 
human pluripotent stem cell derived form embryonic or fetal tissue 
can ameliorate a disease process in an animal model. 
Neural progenitor cells, derived from human EG cells, were 
introduced into the cerebrospinal spinal fluid of rats that had been 
paralyzed as a result of infection with a neuroadapted Sindbis virus 
that specifically targets motor neurons in the spinal cord. All 
animals in which human cells were found had some degree of 
hindlimb recovery. It was clear from the histology of the animals that 
the human cells had differentiated into appropriate neural cell types 
writhin the ventral horns, including motor neurons, the results 
indicated that the major effect of the human cells was to protect host 
neurons from death and to facilitate reafferentiation of motor neuron 
cell bodies. Growth factors responsible for this recovery, produced by 
the human cells, were identified as brain-derived neurotrophic factor 
and transforming growth factor. 
The significance of this experiment appears to be that for this 
disease model, the human cells supply factors that facilitate motor 
neuron recovery following viral damage. However, the cells did 
migrate to the site of injury in the spinal cord, which differentiates 
them from other cellular grafts, and then delivered the factors. Also, 
there was considerable differentiation of the human cells into various 
neural cells types in the cord. 
In a review article on deriving glucose-responsive insulin-producing 
cells from stem cells (Kaczorowski et ai. 2002), mention is made on 
the isolation of such cells from mouse and human ES cells and human 
EG cells, but no new data was presented, only a reference to a paper 
published in 2001. 
EG cell studies in other species 
Several studies on EG cells from other species have been published. 
EG cells from the chick have been demonstrated to yield germ line 
chimeras when transferred to early embryos (Park et aJ. 2003). EG 
cell lines of the mouse were found to colonize not only the epiblast 
but also the primary endoderm of the gastrulating embryo follov\ring 
aggregation with 8-cell embryos (Durcova-Hills et al. 2003). This 
observation was permitted as a result of using a transgenic construct 
effect as a lineage marker for cells of the early embryo. Horii et al. 
(2002) report the serum-free culture of mouse EG cells, a system 
which inhibits the ‘spontaneous’ differentiation due to the presence 
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