*5.3. The PXE Rat*

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− − − − PXE mouse models have been excellent research tools but their small physical size can be an impediment to using certain investigative tools and techniques such as perfusion or organ transplantation. In a recent report, Li et al. described the generation of *Abcc6*−/<sup>−</sup> rats using zinc finger nuclease (ZFN) technology [112]. These animals displayed a calcification phenotype similar to that of *Abcc6*−/<sup>−</sup> mice, with mineralization in the skin (vibrissae), eyes (Bruch's membrane), kidneys, and arterial beds. Plasma PPi levels were depleted by more than 60%, which is consistent with *Abcc6*−/<sup>−</sup> mice and PXE patients. Using in situ perfusion experiments, the authors observed a near abolition of PPi levels in liver (and kidney) perfusates, which has also been described in mice [9,18].
