Biomedical Breakthroughs: Vascular Network Bioprinting

bioprintingThe ability to generate biological tissues using 3-D printing methods – aka. “bioprinting” – may one day help medical researchers and hospitals to create artificial, on-demand custom body parts and organs for patients. And numerous recent advancements – such as the creation of miniature kidneys, livers, and stem cell structures – are bringing that possibility closer to reality.

And now, according to a new study produced by researchers from the University of Sydney, it is now possible to bioprint artificial vascular networks that mimic the body’s circulatory system. Being able to bio-print an artificial vascular network would give us the ability to keep tissue and organs alive where previously it would not have been possible. The body’s vascular network enables it to transport blood and, therefore, oxygen and nutrients, to tissues and organs.

vascularIt also provides a means of transporting waste materials away from tissues and organs. Dr. Luiz Bertassoni. the lead author of the study explained:

Cells die without an adequate blood supply because blood supplies oxygen that’s necessary for cells to grow and perform a range of functions in the body. To illustrate the scale and complexity of the bio-engineering challenge we face, consider that every cell in the body is just a hair’s width from a supply of oxygenated blood. Replicating the complexity of these networks has been a stumbling block preventing tissue engineering from becoming a real world clinical application.

In order to solve this problem, the researchers used a bioprinter to create a framework of tiny interconnected fibers to serve as a mold. The structure was then covered with a “cell-rich protein-based material” and solidified using light. The fibers were removed to leave a network of tiny channels that formed into stable human blood-capillaries within just a week’s time.

stem_cells3According to the University of Sydney study, the technique demonstrated better cell survival, differentiation and proliferation compared to cells that received no nutrient supply. In addition, it provides the ability to create large, life-supporting three-dimensional, micro-vascular channels quickly and with the precision required for application to different individuals.

This is a major step forward for the bioprinting industry, according to Bertassoni:

While recreating little parts of tissues in the lab is something that we have already been able to do, the possibility of printing three-dimensional tissues with functional blood capillaries in the blink of an eye is a game changer.

bioprinter1In addition, Bertassoni claims that the ultimate aim of the research is for patients to be able to walk into a hospital and have a full organ printed with all the cells, proteins and blood vessels in the right place:

We are still far away from that, but our research is addressing exactly that. Our finding is an important new step towards achieving these goals. At the moment, we are pretty much printing ‘prototypes’ that, as we improve, will eventually be used to change the way we treat patients worldwide.

Bioprinting that uses a patient’s own DNA to generate custom-made organs and tissues offers a world of medical possibilities in which organ donors are no longer necessary, and the risk of rejection and incompatibility is negligible. Not only that, it will usher in a world where no injury is permanent and prosthetics are a thins of the past.

Sources: gizmag.com, sydney.edu.au

The Future of Medicine: Adult Stem Cells Cloned for First Time!

3dstemcellsBioprinting and the creation of artificial organs holds a great deal of promise for the field of medicine. By simply layering “bioinks” – which are are made up of stem cells – researchers have been able to form cell cultures and create artificial tissues, ranging from miniature kidneys and livers to cartilage and skin. The only drawback is that the base material in this operation – i.e. stem cells – has posed certain limitations, mainly in that scientists have been unable to clone them from specific patients.

 

However, thanks to a new research method, researchers have just succeeded in returning adult somatic (body) cells to a virgin stem cell state which can then be made into nearly any tissue. This breakthrough is likely reinvigorate efforts to use such cells to make patient-specific replacement tissues for degenerative diseases, for example to replace pancreatic cells in patients with type 1 diabetes. It’s a huge breakthrough in stem cell research in what has already been an exciting year. 

stem_cells2Last May, researchers from the Oregon Health & Science University in Beaverton perfected a process to therapeutically clone human embryos – thus producing cells that are genetically identical to a donor for the purpose of treating disease. In this case, the cells carried genomes taken from fetal cells and the cells of an eight-month-old baby. Then last month, two research groups announced that they had cloned stem cells from adult cells, independently and within a few days of each other.

The first announcement came on April 17th, when researchers at the CHA University in Seoul reported in Cell Stem Cell that they had cloned embryonic stem-cell (ES cell) lines made using nuclei from two healthy men, aged 35 and 75. On then on April 28th, researchers at the New York Stem Cell Foundation have taken body cells from a diabetic patient, transplanted the nucleus from those cells into a donor egg that has had its genetic material stripped, and allowed it to begin dividing.

stem_cells3In the latter case, the researchers reported that the new cells not only began dividing normally, but also began producing insulin naturally—a breakthrough that could eventually lead to a cure for the disease, in which patients are normally reliant on daily insulin injections. As Doctor Egli, leader of the New York Stem Cell Foundation team, said in a conference call with reporters:

We show for the first time that we are able to derive diploid, patient-specific stem cells and are able to induce these stem cells into becoming cells that produce and secrete insulin, showing that this technique should be useful for the development of cell-replacement therapies for diabetes.

The work was published in the journal Nature. Although not noted in the paper, Egli says that the cells work just as well as normally-functioning pancreas cells in non-diabetic humans.

bioprinted heartThe process behind both breakthroughs is known as somatic-cell nuclear transfer, which involves transplanting the “cloned” nucleus of a cell into an existing one that has had its nucleus removed. This is important because it is generally adults who stand to benefit the most from a fresh supply of cells to revitalize their ailing organs. And in addition to age-related treatment, this process offers options for the treatment of diseases that can cause damage to organs with time – in this case, Type 1 diabetes.

However, this day is still many years away, owing to numerous challenges posed by the process. At present, the technique is expensive, technically difficult, and ethical considerations are still an issue since it involves creating an embryo for the purpose of harvesting its cells lone. Obtaining human eggs also requires regulatory clearance to perform an invasive procedure on healthy young women, who are paid for their time and discomfort.

As a result, it is likely to be many more years before this process will becomes medically and commercially viable. That is to say, we won’t be seeing hospitals with their own bioprinting clinics where patients can simply go in, donate their cells, and swap out a diseased liver or damaged pancreas anytime soon. And as long as donated embryos are still a bottleneck, we can expect ethical and legal hurdles to remain in place as well.

Sources: extremetech.com, nature.com, motherboard.vice.com, cell.com