The more research I do on the possibility of getting the Lab grown cartilage implantation to work, the more and more it seems that the possibility is more and more true. I recently found another article showing how researchers in labs around the world have gotten the cartilage to be grown, and quite easily, using 90s printers. (source: http://www.nytimes.com/2013/08/20/science/next-out-of-the-printer-living-tissue.html?pagewanted=2&_r=4&ref=todayspaper&)
A Daryl D’Lima, who is the head of an orthopedic research lab at the Scripps Clinic, has already succeeded in getting bio-artificial cartilage from extracted bovine tissue.
First, he and his team succeeded from getting an old inkjet printer (a 1990s-era Hewlett-Packard printer, a Deskjet 500, with bigger nozzles, a thermal inkjet printer) to put on layer upon layer of a gel containing the cells that cartilages are composed of. The ideas was to replace the ink in the cartridges with their cartilage-making mixture, which consisted of a liquid called PEG-DMA and the chondrocytes. (This I am assuming is from bovine sources).
Second, he and his team have also gotten some bit of cartilage that have been extracted from people who have already gone through knee replaceent surgery.
Like any good researcher, he is cautious in his optimism, and the speed at which his research in the lab will be viable to be placed in the market for the general public to use. Technically speaking, the process might still need to be perfected a little, but it seems most of the challenges at this point is beauracratic in nature, (ie conduct clinical trials, and getting regulatory approval)
D’Lima’s hope is to have just a printer in the OR one day right next to the surgeons. It will… “custom-print new cartilage directly in the body to repair or replace tissue that is missing because of injury or arthritis…”
This device that D’Lima’s team have build is not really like the 3D Printers that are conventionally used in manufacturing companies like PLA and ABS. This bioprinters print cells, but what is actually extruded through the extruder head is a gel or liquid medium. The gel medium would eventually act like the extracellular matrix of the cell, and that eventually turns into living tissue.
When we look closer at the possibility of pushing the cells in the gel medium through the 3d bioprinter’s head without killing the cells, it seems that the cells did indeed survive. The heat pulse was so rapid that most cells survived the process. (Important thing to remember: There is actually two main ways to get the tissues made. The 2nd approach on making living functional tissues involve starting with a scaffold first and then adding cells into it.)
The advantage of using a bioprinter to print layers of gel and cells on top of the previous layer is that with the bioprinter, it can control the placement of the cells to be similar to cell layout and overall cell structure and aligment of natural cell arrangements. Remember that to have a cartilage to work like a natural growth plate, the cells (chondrocytes) will need to be stacked on top of each other in a “column” like structural alignment.
What we do have in terms of bad news is that we probably will not have the bioprinters making functional hearts in a few years though. That might take more like 20-30 years. The company Organovo is mentioned again. Thomas Boland, a researcher at the University of Texas has still been able to say that the future is in regenerative medicine.
It does however say that when it comes to the cartilage tissue, it is much easier to bioprint than most other tissues. Dr D’Lima says the following “… cartilage might be the low-hanging fruit to get 3-D printing into the clinic”
The reason why cartilage tissue is easier than the others is because it is simpler. The chondrocytes in the ECM is actually quite low maintenance. The cells don’t get their nutrients through blood vessels, but through diffusion through the ECM.
Here at NHGH I will be the first person to acknowledge that what Dr. D’Lima is trying to create is articular cartilage for the ends of bones, not epiphyseal cartilage types, although at the structural level, they are the same thing. Articular and Epiphyseal cartilage are both hyaline cartilage. We want to get epiphyseal type hyaline cartilage created, which will be implanted between two bone segments.
The natural growth plate or epiphyseal cartilage does seem to get its main source of nutrients from blood vessels, that run to the epiphysis and the metaphysis. That might be a technical challenge if we tried to shift the expected functon of the cartilage we are bioprinting to not just stay in cartilage form (for treating articular cartilage damage due to osteoarthritis) but to eventually grow volumetrically and push overall to become longer and make bones longer.
What is good to know however is that the body naturally produces chemical signals that would cause the local area of an osteonomy (bone cut) to start to develop vascularization. Over time, blood vessels will automatically grow into the cartilage implant. This process is however slow.