Editor | On 13, Jan 2019

Darrell Mann

Currently, doctors have to throw away more than 80 percent of donated tissue used for joint replacements because the tissue does not survive long enough to be transplanted. Now, following a recent study, University of Missouri School of Medicine researchers have had their patent granted for a new technology that more than doubles the life of the tissue. This new technology was able to preserve tissue quality at the required level in all of the donated tissues studied, the researchers found.

“It’s a game-changer,” said James Stannard, co-author of the study and J. Vernon Luck Sr. Distinguished Professor of Orthopaedic Surgery at the MU School of Medicine. “The benefit to patients is that more graft material will be available and it will be of better quality. This will allow us as surgeons to provide a more natural joint repair option for our patients.”

The technology, called the Missouri Osteochondral Allograft Preservation System, or MOPS, more than doubles the storage life of bone and cartilage grafts from organ donors compared to the current preservation method used by tissue banks.

In traditional preservation methods, donated tissues are stored within a medical-grade refrigeration unit in sealed bags filled with a standard preservation solution. MOPS utilizes a newly developed preservation solution and special containers designed by the MU research team that allows the tissues to be stored at room temperature.

In the study, clinical outcomes of the standard preservation approach and the new MOPS technology were assessed. Researchers found that by using MOPS, the storage time for donor tissue could be extended to at least 60 days, versus the current storage time of approximately 28 days.

“Time is a serious factor when it comes to utilizing donated tissue for joint repairs,” said study co-author James Cook, director of MU’s Comparative Orthopaedic Laboratory and the Missouri Orthopaedic Institute’s Division of Research. “With the traditional preservation approach, we only have about 28 days after obtaining the grafts from organ donors before the tissues are no longer useful for implantation into patients. Most of this 28-day window of time is used for testing the tissues to ensure they are safe for use. This decreases the opportunity to identify an appropriate recipient, schedule surgery and get the graft to the surgeon for implantation.”

The patent in question was granted as US10, 039,277 on 7 August. In addition to James Cook and a colleague from the University of Missouri, the list of inventors also includes a pair from Columbia University in New York.

Here’s what the background description has to say about the problem being solved:

Allograft or other tissue samples are used to treat many diseases and/or defects. These grafts are procured from organ donors and must be stored to allow for viral and bacterial testing for safety prior to shipping to surgical centers for implantation into patients. Based on studies looking at viability of the cells in the grafts, recommendations have been given for implanting tissues as soon after harvest as possible in order to maximize success. Safety testing takes a minimum of 7 days and more often 10-14 days for final clearance. Storage of tissue, such as allograft tissue, for transplantation or other scientific or medical purposes allows time for medical testing, recipient patient preparation, or to preserve tissues for other purposes. Storage conditions for allograft or other tissue samples may influence tissue viability, integrity, and/or sterility.

Here’s how we might best map the problem onto the Contradiction Matrix – ‘Duration of Action’ being the primary attribute the invention is trying to improve, and stability (or lack thereof) being the attribute causing the inadequate preservation life.

And here’s the inventive steps used to create the solution:

…A process for osteochondral tissue preservation comprising storing the osteochondral tissue at room temperature in a container comprising a serum-free culture medium comprising dexamethasone for from about 7 days to about 70 days prior to implantation, wherein at least 70% of the cells of said osteochondral tissue remain viable after said storing compared to the viability of the cells of the osteochondral tissue at day 0.

Essentially, we get two illustrations of Principle 35, Parameter Change, in action here. The first is a switch in the culture medium in which the tissue is preserved. The second is somewhat more counter-intuitive and relates to the increase in temperature from the refrigerated convention to ‘room temperature’. As such I think it represents just what Principle 35 is all about: changing a parameter – temperature in this case – to such an extent that a non-linear effect is achieved. It is not, in other words, about optimizing a parameter, but using variation of that parameter to cross some kind of non-linear boundary. This inevitably involves some kind of bravery. The level steps up even further when, like the team of inventors here, they try changing the parameter in the ‘wrong’ direction.

Not to mention the later claim concerning the container. Check out Principles 24, 31 and 39 in this description:

…A method for preserving osteochondral tissue at room temperature in a chamber comprising a serum-free culture medium comprising dexamethasone prior to implantation, the method comprising: placing the osteochondral tissue in a chamber base with said culture medium, the chamber base configured to maintain the tissue and the serum-free culture medium comprising dexamethasone; forming a tissue preservation chamber by covering the chamber base with a lid to form a barrier to contaminants, the chamber comprising at least one filter, a media inlet coupled to at least one filter for maintaining a sterile environment inside the chamber, and a media outlet, the media outlet including a media outlet conduit that extends into the chamber to permit removal of media; wherein the media outlet comprises a one-way valve to prevent reentry of culture medium exiting the chamber; and storing the osteochondral tissue at room temperature for from about 7 days to about 70 days prior to implantation…

It’s the real thing, people…