Biomedical Engineering Reference
In-Depth Information
Moreover, some authors suggested that injected cells could
increase the risk of augmentation of sympathetic nerve density,
resulting in an increase of cardiac contractile performance.
Sympathetic hyperinnervation may also result in life-threatening
ventricular arrhythmias [66]. Although patients with myocardial
infarction may have arrhythmias triggered by ischemia and
anatomic conduction block due to myocardial scarring, the
enhanced spatial inhomogeneity of cardiac innervations may play a
role in lethal ventricular arrhythmia. Sympathetic nerve activation
exerts significant effects on electrophysiological properties such as
the automaticity, triggered activity, refractoriness, and conduction
velocity of myocardial cells. Increased and heterogeneous
cardiac innervations might amplify the spatial inhomogeneity
of electrophysiologic properties and facilitate the initiation of
ventricular arrhythmia. A recent study reported that cardiac cell
transplantation is associated with severe ventricular arrhythmias in
some patients [56], suggesting that proarrhythmic remodeling, such
as sympathetic nerve sprouting, may occur after cell transplantation.
3.7
Summary and Conclusions
Although the direct injection of cells can successfully cure a small
damaged area [67], the direct injection of cells into the heart is
hazardous due to a possible blockage of circulatory pathways,
resulting in more life-threatening complications and increasing the
risk for arrhythmia. In addition, injected or transplanted cells are
unable to fuse stably with the host heart tissue for regenerating
sufficient cardiac mass in the thinned scar area. Therefore, it is very
important to improve the adhesion between the host heart tissue
and the transplanted cells for fixing the cells directly onto the host
heart wall. To overcome the problems, we have utilized cell sheet
technology, which allows us to transplant cells in vivo for treating
human heart diseases. Cell sheet transplantation can promise a new
therapeutic strategy for partial cardiac tissue reconstruction.
References
1. Reinlib, L., et al. (2000). Cell transplantation as future therapy for
cardiovascular disease? A workshop of the National Heart, Lung, and
Blood Institute,
Circulation,
101
, pp. 182-187.
