The news for today is that NASA's Centennial Challenges Program and the Methuselah Foundation's tissue engineering initiative New Organ have joined forces to develop the Vascular Tissue Challenge, which is currently public in a draft form as an RFI. The intent is to divide a $500,000 purse between up to three teams who can advance the state of the art in tissue engineering by reliably producing thick sections of vascularized living tissue.
I'm sure you've all seen the announcements roll in over the past few years as research groups have built small organoids that function correctly for their organ type: slivers of pancreatic tissue, thymus tissue, kidney tissue, and so forth. It has, I think, been amply demonstrated that the research community has the development of methodologies needed to build complex, functional tissue well in hand. There is a great deal that can be done with even such tiny slices of tissue, ranging from integration into tools that speed research to use as matched tissue patches for patients with damaged organs. A little bit of a pancreas or a liver - or a dozen little bits, or more - is actually quite useful in the context of diseases, age-related and otherwise, that cause progressive damage to those organs.
However, not all is roses and rainbows in the field. Growing much larger sections of tissue from the starting point of cells and entirely artificial scaffolds, with the goal of creating whole organs to order, as needed, and matched to the recipient patient, remains to be accomplished. The proliferation of organoids can be contrasted with the absence of larger solid structures. The challenge here, and this has been the blocking issue for a decade, is that the research community cannot yet reliably create tissue that is equipped with the network of tiny blood vessels needed to keep the cells alive and provisioned with nutrients. Thinner tissues can get by without blood vessels, as fluids will diffuse through their structure, but the blood vessels are absolutely required by any tissue much thicker than a centimeter or so.
This is why decellularization of donor organs has taken off: stripping out the cells is is a way to obtain a scaffold, the natural extracellular matrix, that has the intricate blood vessels and the chemical cues to guide newly introduced cell populations to repopulate and rebuild the correct structures. This cannot yet be done for artificial scaffold materials, such as those turned out by 3-D printers, or at least not in anything more than a very early and limited way. Once microvasculature can be produced in engineered tissue in a robust fashion, however, the gate is flung open and the creation of organs in a variety of ways will happen just a few years later at most. Given all of this, vascularization of tissue is an important goal, and a good place to add incentives into the research process.
The Vascular Tissue Challenge is a $500,000 prize purse to be divided among the first three teams who can successfully create thick, human vascularized organ tissue in an in-vitro environment while maintaining metabolic functionality similar to their in vivo native cells throughout a 30-day survival period. NASA's Centennial Challenges Program is sponsoring this prize to help advance research on human physiology, fundamental space biology, and medicine taking place both on the Earth and the ISS National Laboratory. Specifically, innovations may enable the growth of de novo tissues and organs on orbit which may address the risks related to traumatic bodily injury, improve general crew health, and enhance crew performance on future, long-duration missions.
The Vascular Tissue Challenge rules are currently open for public comment. If interested in this challenge, please provide your feedback.
The Centennial Challenges program is seeking input on a Vascular Tissue challenge being considered for start in 2016. The challenge would require competitors to create a thick tissue with fully functioning vascular systems, similar to the tissue found in the heart, lungs, liver or kidney. This RFI is seeking feedback from potential challengers. Comments must be submitted in electronic form no later than 5:00 pm EDT, April 15, 2016.
The ability to provide oxygen and nutrients to thick human tissue by adequate vascularization of layers of cells to ensure metabolic functions similar to native in-vivo tissues has not been reliably demonstrated. Developing this capability will enable new research initiatives that may bring real solutions to organ disease, skin burns and other medical concerns. NASA's objective for this challenge is to produce viable thick-tissue assays above and beyond the current state of the art technology.
Competitors will be asked to produce an in-vitro vascularized tissue that is more than 1 centimeter in thickness in all dimensions at the launch of the trial and maintains greater than 85% survival of the required parenchymal cells throughout a 30-day period. Tissues must provide adequate blood perfusion without uncontrolled leakage into the bulk tissue to maintain metabolic functionality similar to their in-vivo native cells. Histological measurement of the quality and amount of functional performance will be required to determine survival of parenchymal tissue. Teams must demonstrate 3 successful trials with at least a 75% trial success rate to win an award. In addition to the in-vitro trials, teams must also submit a Spaceflight Experiment Concept that details how they would further advance some aspect of their tissue vascularization research through a microgravity experiment that could be conducted in the U.S. National Laboratory (ISS-NL) onboard the International Space Station.
If you happen to know anyone in the tissue engineering community, please do direct their attention towards this initiative.