If cells are primed by the degenerating environment present in HD progression but do not have the appropriate signals to proliferate there will be no increase in neurogenesis.
One possible explanation for the increase in neurosphere numbers observed in the 33-week-old HD hippocampus is that the degenerating hippocampal environment present during HD progression may in fact lead to the release of factors in vivo which may help to maintain the stem/progenitor cell pool at its normal adult level, but not allow these cells to actively proliferate.
Blackness, in the course of the eighteenth and nineteenth centuries, became seen as a mere disease, with negroes descended not from Adam or even the fabled "mark of Cain" but degenerated from corrupted environment, atavistic savagery, or worse.
However, there are still challenges presented by the degenerating recipient retinal environment that must be addressed as we move to translating these technologies towards clinical application.
Furthermore, these biomaterials must resist accelerated degradation within the proteolytic environment of degenerate IVDs while supporting integration with host tissue.
The development of vector systems with better glial tropism may be required to improve the ability of Nurr1 + Foxa2 to create a neuroprotective environment surrounding degenerating mDA neurons.
In addition, the degenerate disc is a hostile environment with increased production of cytokines that alter matrix synthesis and expression of matrix degrading enzymes [ 19, 21- 23].
However, many problems still need to be addressed before this can be a practical proposition, key amongst which are ensuring that transfected cells can continue to synthesize active product within the environment of the degenerate human IVD [ 47].
Although they were the "cream of the crop" in their communities, Sherif claimed that when exposed to a competitive environment they quickly degenerated into "disturbed, vicious … wicked youngsters".
Although there is currently no evidence confirming the presence of fHAs within disc tissue, it may be reasonable to assume that the sequence of catabolic and inflammatory events within the degenerating disc could provide an environment conducive to the production of fHAs.
