Bioprinting 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.
Last 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.
In 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.
The 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.