Animal Tissue Valves
Preservation
Carpentier-Edwards
Since 1972 glutaraldehyde has been used to preserve and sterilize.
1982- glutaraldehyde and surfactant polysorbate 80 introduced, reacts with a gluteraldehyde resistant micro-organism and has calcium mitigation properties.
Hankcock II- glutaraldehyde and surfactant sodium dodecyl sulfate, calcium retardant.
Epic™ Xenograft- 2001 uses Linx anticalcification treatment.
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Unlike any other current anticalcification technology, innovative Linx technology is believed to have multiple effects on cusp tissue, providing a powerful shield against valve mineralization. The action of Linx technology: |
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Reduces glutaraldehyde toxicity associated with calcification |
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Removes 99% of the cholesterol and 94% of the phospholipids, which are potential binding sites associated with tissue calcification |
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Greatly reduces the subsequent uptake of lipids in vitro |
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Results in stable changes to the collagen triple helix, as evidenced through infrared spectroscopy St. Jude Medical. "SJM Epic Valve." 2008 1. 09 Mar 2008. |
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Acellularized Valve Seeding
Research in to acellularizing porcine valves has lead to viable xenogenic acellularized matrix that can be repopulated with human cells. This involves treating a viable porcine valve with detergent extraction procedure while simultaneously culturing human cells from the patient in vitro. Finally when the porcine valve is prepared and the human autocells are matured, the acellularized porcine valve can be seeded with the autologous human cells. After several days of culturing the valve, it is found that a “grossly maintained” matrix is formed out of the cells from the human patient (Bader et al).
Another study used similar technique to turn heart valves from cadavers into usable autocellular valves that could be implanted into a human being with the same results. The advantage to using a human heart valve to start lies in the prevention of spreading disease and in maintaining human, not porcine, valve dimensions. One of the advantages of these tissue matrix grafts is that there are extracellular proteins present for the adherence of the seeded cells. Clinical testing has not yet been done on these types of valves (Batrinac et al.) (7).
A) native aortic wall; B) aortic wall after decellularization. (Cebotari et al.)
In the future this research offers the hope that it might allow tissue valve replacement that will not elicit a human immune system response, and will therefore last longer and be viable in more cases. There is also the hope that this will allow for a living valve to be implanted that allows for growth and prevents calcification, making this a great technology to treat valve diseases in children and other long term patients.