Neural Stem Cells Will be No Use as Immunomodulators

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Foetal neural stem/precursor cells (NPCs) possess powerful
immunomodulatory properties which enable them to protect the brain from
immune-mediated injury. A major issue in developing neural
stem/precursor cell (NPC) therapy for chronic neuroinflammatory
disorders such as multiple sclerosis
is whether cells maintain their immune-regulatory properties for
prolonged periods of time. Therefore, we studied time-associated changes
in NPC immunomodulatory properties. We examined whether
intracerebrally-transplanted NPCs are able to inhibit early versus
delayed induction of autoimmune brain inflammation and whether
allogeneic NPC grafts continuously inhibit host rejection responses. In
two experimental designs, intraventricular foetal NPC grafts attenuated
clinically and pathologically brain inflammation during early EAE
relapse but failed to inhibit the disease relapse if induced at a
delayed time point. In correlation, long-term cultured neural precursors
lost their capacity to inhibit immune cell proliferation in vitro. Loss
of NPC immune functions was associated with transition into a quiescent
undifferentiated state. Also, allogeneic foetal NPC grafts elicited a
strong immune reaction of T cell and microglial infiltration and were
rejected from the host brain. We conclude that long-term functional
changes in transplanted neural precursor cells lead to loss of their
therapeutic immune-regulatory properties, and render allogeneic grafts
vulnerable to immunologic rejection. Thus, the immunomodulatory effects
of neural precursor cell transplantation are limited in time
This study looked at the effect of neural stem cells (stem cells that can make nerve and glial cells) to immunomodulate. They could do this when applied early in experimental disease but once disease was established they did nothing as immunomodulators. However, you do not treat MSers before they get MS. Then it says to me that neural stem cells do not immunomodulate and so much of the studies published previously is simply hype. The lab doing this study was one of those leading way to show the immunomodulation by stem cells story and this work suggests that their view will be modified about benefit. However, I think that we should not be expecting them to having dramatic or in fact any immunomodulatory effect in MS. The question is can they become myelin-repair cells? I have viewed much of the so called immunomodulation studies using stem cells with a sceptical eye and this tends to confirm this view. 

Even our own work has not shown nuch immunomodulatory actions of these cells. When it does occur it is usually marginal to what can be achieved with card-carrying immunomodulatory drugs. However we shall see. There are studies with other types stem cells that have also been reported to be immunomodulatory, which are in trial in MS as we speak so we will see what happens.

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