ECM-derived materials

The history of extracellular matrix (ECM)-derived medical implants is one of innovation and reinvention that spans over seven decades of cardiovascular surgery. The applications of ECM-deiived implants in these fields are broad replacement of cardiac valves, reconstruction of arteries and veins, creation of hemodialysis access, extending the lifespan of vascular reconstructions, and repairing trauma. Although there are currently a large number of ECM-derived prosthetics available for human use, understanding their similarities and differences, as well as their overall position in the general arena of implantable devices, will allow continued evolution and new applications for these versatile ECM-derived materials. 

The use of ECM-derived materials in cardiovascular surgery falls into four broad categories bioprosthetic heart valves, septal defects closure, coronary and peripheral vascular repair, and pericardial closure. Each represents a unique application with significantly different anatomic and physiologic requirements. Several of these are treated in depth by others in this volume or elsewhere. " Of these, pericardial closure is perhaps the most often overlooked procedure and the one I ve elected to review here. 

The selectivity of enzymes offers the potential for better controlling macro-molecular structures without the need for wasteful protection/deprotection steps [91]. In another biomimetic approach, enzymes can be exploited for the cross-linking of ECM-derived materials using mild conditions with the aim to optimize the scaffold mechanical characteristics to the application. 

In order to functionalize scaffolds to mimic the native cell environment, different strategies are available. Recombinant DNA technology can be used to design artificial ECM proteins to avoid the aforementioned complications that can arise with naturally derived materials [60], However, there is little known about the long-term... 

With regard to cardiovascular surgery, although ECM-derived medical implants can be constructed from a variety of materials, there are several desirable properties in common to these materials when used in the vascular system. The final implantable object should have a low risk of restenosis and calcification. The material should be resistant to infection, antithrombogenic, stable, durable, and easy to obtain, handle, and prepare. Ideally, the ECM-based biomaterial should have a compliance comparable to host vessels. ... 

Allografts and xenografts represent an important subset of products in the broader class of ECM-derived biomaterials, and for our purposes wiU be defined as any material for implantation in humans resulting from the processing of organs or tissues of a living organism, whether mammalian or otherwise. I have excluded products that... 

Natural ECM-derived scaffolds are promising materials, with specific immunomodulatory properties, capable of promoting regeneration (Valerio et al., 2015 Turner and Badylak, 2015). Some examples already commercialized include acellular dermis... 

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