Dec 12, 2016 | By Benedict
Scientists in China have announced a breakthrough in stem cell biotechnology after their 3D bioprinted stem cell grafts implanted in monkeys were able to promote vascular tissue regeneration. Merging of the 3D printed blood vessels with the organic aorta took just seven days.
Hailed by many as one of the most exciting areas of biotechnology and medicine, 3D bioprinting could someday save countless lives. That’s because, unlike regular plastic and metal 3D printers, 3D bioprinters can be used to fabricate human tissue and organs from stem cells, and these 3D printed body parts—once perfected—could theoretically be transplanted into human bodies to replace defective livers, kidneys, and even hearts.
At present, most researchers in the field of 3D bioprinting have been realistic about the timescale required to 3D print transplantable human organs. Many appear well on the way to making such organs, but believe it could be decades before they are fully functional. Those hopeful of seeing 3D printed transplantable organs must also factor in the time it will take for the relevant authorities to eventually test, evaluate, and grant approval to 3D bioprinting procedures for medical use.
Because of the high-risk nature of transplanting organs, 3D printed tissue and organs are these days more likely to end up in pharmaceutical labs than the operating theater. Why? 3D bioprinted tissue and organs can be used to simulate the equivalent parts of the human body, and can therefore be used ex vivo to test the effects of drugs on the body. Despite their usefulness for drug screening, these fabricated body parts lack many of the attributes of natural human organs, and would therefore be unfit for human transplantation.
Given the fairly conservative timescales offered by many experts in the 3D bioprinting sphere regarding transplantation, and given that most bioprinting applications can be found in pharmaceutical industry, it has come as a major shock to hear that scientists in China have made a massive major breakthrough in stem cell biotechnology, as they witnessed vascular tissue regeneration from 3D bioprinted stem cell grafts implanted in a group of 30 monkeys. The announcement of the breakthrough was made by Dr. Y. James Kang, Chief Scientific Officer and Chief Executive Officer of Revotek, and Director of the Regenerative Medicine Research Center of West China Hospital at Sichuan University.
After overseeing the successful transplant of the 3D printed blood vessels in the large group of rhesus monkeys, Dr. Kang called a press conference to present his findings in detail. According to the biotechnology expert, a team of researchers used a Revotek-T 3D Blood Vessel Bioprinter to print biologically active blood vessels from a “Biosynsphere,” or stem cell bioink, which was prepared from the autologous adipose mesenchymal stem cells (ADSCs) of the monkeys. The 3D printed blood vessels were then used to replace a 2 cm segment of the monkeys’ abdominal aorta.
The researchers behind the groundbreaking 3D bioprinting technology have created a short animation (below) which shows the 3D printing process used to create the blood vessels. First, the temperature-sensitive hydrogel is printed to surround a metal tube. Next, a layer of the “Biosynsphere” is 3D printed on top of the hydrogel, forming a long, tubular structure made of the monkeys’ stem cells. Finally, a graft assemblage is placed over the Biosynsphere layer, after which the underlying layer of hydrogel is dissolved at 37°C, leaving only the aorta-shaped tube of stem cells and its protective graft assemblage. A few years ago, it would have been impressive just to 3D print the blood vessels in this way, but today the news is even more significant: the monkeys are using the blood vessels as if they were their own.
Dr. Kang reported that, five days after the surgery took place, the ADSCs sequentially differentiated into endothelial cells, smooth muscle cells, and other cell types of vascular tissue. Just two days later, the 3D bioprinted blood vessels began to merge with the rhesus monkeys’ own abdominal aorta, and this merging process was completed in just a single month. After closely monitoring the health of the monkeys over the course of several further months, the researchers determined that the 3D printed blood vessels behaved exactly the same as the monkeys’ original abdominal aorta. Moreover, the creatures required no further treatments besides anticoagulants during the first five days after surgery.
The breakthrough in China is huge news for the 3D bioprinting world, and presents an exciting prospect for the development of similar treatments for human subjects. With many people around the world suffering from various cardiovascular diseases, researchers may now be looking to adopt Dr. Kang’s methods to develop methods of 3D printing human blood vessels that are fit for transplantation. The Chinese researchers also believe that their work will also greatly affect stem cell research of all varieties.
The incredible story of monkeys receiving 3D printed blood vessels has already captured the attention of several television news reporters in China, which were granted access both to Dr. Kang’s press conference and the operating room where the implantation was carried out. See the short (Chinese language) reports in the videos below.
Long story short - numerous groups from around the world have been looking into using stem cells and 3 d printers to print blood vessels. There are several applications for this, to testing drugs and studying human physiology, to using blood vessels in transplants. This is not the first time 3d vessels have been printed, but AFAIK this is the first time they have been surgically implanted, although this was only done in resus monkeys. To be of use, it has to be doable in humans.