Question: How do we get stem cells?

Lucy McGowan answered on 16 Jun 2020:

There are different types of stem cells with different types of potency; potency means the ability of a stem cell to become any kind of specialised cell. For example, a pluripotent stem cell can become almost any type of cell in the body, like skin, heart, blood, immune cells, liver, bone, brain e.t.c. However, a multipotent stem cell can only become certain types of cells such as immune or blood cells.
Embryonic stem cells are found in embryos. In a young embryo these stem cells are pluripotent. This is how just a few cells in a tiny human embryo can turn into a very complicated fully grown adult human with lots of different cell types.
Adult humans have stem cells in the body too, but these are a bit more specialised than the ones in embryos. There are lots of stem cells in the bone marrow which turn into the white blood cells of the immune system and the red blood cells which carry oxygen through the blood. There are also mesenchymal stem cells throughout the body; these stem cells replenish the skin, heart, bone, fat and neural cell populations in the body.
Sometimes people have faulty stem cells in diseases such as cancer. In this case, they may need a stem cell transplant. A bone marrow transplant takes stem cells from a healthy donor and puts them in the body of the sick patient. If successful, these stem cells replace the diseased stem cells in the patient. It can be very hard to match a donor with a patient though and sometimes it doesn’t work. We can also get stem cells from the umbilical cord blood after birth.
More recently, a way of creating induced pluripotent stem cells (iPSCs) was discovered in Japan. It was discovered that by feeding a specialised cell such as skin cells a few special factors, these cells can be turned BACK into stem cells! This is super exciting because if scientists can successfully scale up this technology, iPSCs may be used to treat all sorts of diseases like neurodegeneration, heart disease, blindness and scarring in the future. The aim is that some cells (such as skin) could be taken from a patient, grown in the lab under special conditions and turned back into stem cells, then transplanted back into the patient where they help to heal the patient. This would be better than using donors because the stem cells would be an exact match for the patient. There have been some really promising examples of this kind of treatment in clinical trials, but for now we are a little way off this becoming the norm for treating diseases due to limitations in the technology.