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three-dimensional ultrasound is available for small-animal protocols, which
in principle should improve the accuracy of left ventricular function calcula-
tions compared to traditional two-dimensional ultrasound, which fails to
account for changes in ventricular geometry of diseased hearts.
Electromechanical mapping provides an additional technique to augment
the monitoring of disease progression and the benefit of cell-based therapy
[91]. Nonfluoroscopic, electroanatomical navigation systems use ultralow
magnetic field sources and catheter electrodes to track the trajectory of a
catheter independently of contrast or direct visualization. These systems
allow precise guidance of a diagnostic catheter or delivery catheter along
with the acquisition of spatial, electrophysiological, and mechanical infor-
mation to re-create a three-dimensional map of the viable myocardium.
The diagnostic utility of electromechanical mapping has been validated in
preclinical and clinical studies to quantify the location and degree of pos-
tischemic myocardium. This detailed functional map is dependent on the
magnitude and timing of the infarction, thus enabling the system to be use-
ful to guide cell-based interventions for direct delivery of cells to regions of
particular interest [90].
6.3 Conclusion
Triggered nuclear reprogramming through ectopic expression of stemness
factors has revolutionized a strategy for embryo-independent derivation
of pluripotent stem cells. iPS cell technology offers breakthroughs in stem
cell biology by promising to invalidate chronological age, reverse cell fate,
and restore an atavistic embryonic-like potential of ordinary adult cells. To
these ends, iPS cell clones have demonstrated functions previously dem-
onstrated only by natural embryonic stem cells to produce all tissue types.
Furthermore, the regenerative potential of iPS cells has been confirmed in
head-to-head studies between parental fibroblasts and reprogrammed prog-
eny in the setting of ischemic heart disease, providing the first direct evidence
of the potential therapeutic value of bioengineered pluripotent stem cells in
the setting of heart disease [71]. Specifically, transplantation of iPS cells in
the acutely infarcted myocardium yielded structural and functional repair
to secure performance recovery as qualified clones contributed to in vivo tis-
sue reconstruction with “on-demand” cardiovasculogenesis. Although the
full clinical impact of iPS cell-based technology has yet to be realized, proof-
of-principle studies coupled with real-time in vivo imaging modalities are
being conducted to establish the safety and efficacy profiles, enabling further
optimization of clinical-grade production and matching the right cell type
to the most appropriate target disease. Therefore, converting self-derived
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