To Matrigel or Not to Matrigel

To the Editor-in-Chief:

Being in the business of axial vascularization and its application on tissue engineering and basic science for almost a decade, we still simmer with excitement every time a new publication from the Bernard O’Brien Institute of Microsurgery surfaces in the literature. In the article entitled “Angiogenic Growth Factor Synergism in a Murine Tissue Engineering Model of Angiogenesis and Adipogenesis,”1 the authors present a well planned, well conducted study on the effects of vascular-related growth factors on adipogenesis and angiogenesis. They confirm that modulation of the assembly process is the result of a complex spatial and temporal interplay of signals and that to augment angiogenesis one has to avail oneself of several vasoactive molecules rather than one single substance. The use of Matrigel, however, prompts controversy, even when used as a factor-poor version. The authors themselves have shown it to be both adipogenic and angiogenic. Because it retains its adipogenic properties in this study, it is conceivable to believe that it retains its angiogenic properties as well. That would render it a black box for studies on angiogenesis. Using fibrin clots to perform similar studies, we have found a double benefit: use of fibrin gives rise to experiments with a clinical perspective2,3 because it is FDA approved (Matrigel, on the other hand, with the maximum thinkable likelihood, will never be granted approval), and the effects of vasoactive substances immobilized in fibrin are more readily attributable to the substances themselves rather than the matrix.4 We would also like to note that the effects of vascular endothelial growth factor/basic fibroblast growth factor are not species-specific in this setting, and the use of human recombinant variants of the growth factors produces equally vivid angiogenesis in our rodent model.4