All organisms consist of cells and form from preexisting cells. These cells constantly divide to replace dead or damaged cells. Cellular division, or mitosis, allows organisms to replace injured cells as quickly as possible; however, with major wounds, such as third degree burns or hernias, healing takes a long time. In 1995, Cook Biotech discovered the unique properties of the porcine small intestinal submucosa, and developed the small intestinal submucosa (SIS) technology. They originally thought the small intestine could be an implant for arteries in humans, but discovered the regrowth property of the intestine instead. This layer of the pig small intestine, after killing off all living cells within the structure, stimulates cell regrowth and withstands tears or breakages. Where ever the matrix is located, it supports restoration of the cells of that type. Put the SIS technology onto skin, and a regrowth of skin cells will be observed. This material will not encapsulate when surgically implanted, but rather is gradually altered, leaving behind organized cells and tissues. As a product from a pig, it is organic and natural for the body.
Over the years, more developments and discoveries improved the SIS technology. Today, Cook Biotech released their most recent designs: the first hybrid biologic and synthetic hernia repair graft. This product combines the cell growth stimulate of the biologic graft and the strength of a synthetic graft. It has been cleared by both the United States and European regulatory agencies and is available for use by physicians. The product, called Zenapro™ Hybrid Hernia Repair Device, mixes a polypropylene mesh with layers of Cook Biotech’s extracellular matrix biomaterial, the SIS.
The extracellular matrix is the structural and functional substance that surrounds cells in tissues. The composition of the extracellular matrix differs a little based on which tissue it is in, but is composed by four molecules: structural proteins, glycoproteins, glycosaminoglycans and proteoglycans, and matricellular proteins. The structural proteins is the most abundant protein within the extracellular matrix, and is usually collagen. To allow movement of cells through the matrix, glycoproteins help bind cells to the collagen. Glycoproteins also maintain hydration by absorbing water and bind growth factors, and important part of cell signaling. The matricellular proteins add functional utility to the extracellular matrix. SIS is the extracellular matrix from the pig’s small intestine, which is part of the reason why it stimulates cell regrowth. Scientists are still unsure why SIS will stimulate any sort of cell regrowth, rather than just intestinal cell regrowth, and research is being done to discover why this mysterious observation occurs.
A unique characteristic in the production of SIS technology is that each product must be handmade. The laboratory contains vacuum seals, sewing machines, and dried layers of SIS. Skilled workers stitch layers of SIS together to the desired thickness for particular purposes. Skin requires thinner, rectangular layers to cover large areas, whereas hernias require a thick, cylindrical shape to fill in the hole and stimulate regrowth. SIS technology can be used in the eyes, cardiovascular system, or even in an anal or rectovaginal fistula. The many uses and unique qualities of SIS predict a future with more biologic surgical devices and implants in the future of medicine.