Biomedical Engineering Reference
In-Depth Information
In a preliminary study [7], we have followed the function of hMSC-based
biological pacemaking through 6 weeks post-implantation and have found that the
rate generated is stable. Equally importantly, we have used staining for immune
globulin and for canine lymphocytes to determine if rejection of the hMSCs were
occurring. At 2 week and 6 week time points, there was no evidence for humoral or
cellular rejection. This is consistent with the earlier work of Liechty et al. [4]
suggesting that hMSCs may be immunoprivileged. If more detailed investigation
demonstrates this to be the case, then it would abrogate any need for
immunosuppression. Certainly any need for immunosuppressive drugs would be a
major detriment to cell therapy approaches, and would argue strongly in favor of
staying with electronic pacemakers.
Fig. 12. a
H&E stain showing basophilicstained stem cells and normal myocardium.
b
and
c
show, respectively, vimentin and CD44 staining of a node of human mesenchymal stem cells in
canine myocardium.
d
Detail of vimentinstained cells interspersed with myocardium.
Magnification 100·(
a
) and 400·(
b-d
) (reprinted by permission from reference [8]).
4 Conclusions
Much has been accomplished in showing that both viral and hMSC platform
approaches are effective in generating biological pacemakers. But as we stated at the
