So I was in this meeting about 2 weeks ago on dental research. Interestingly they had invited an expert on human embryonic stem cells to give a lecture. It most most interesting. I will try to convey some of the points he was conveying.
The creation of human embryonic stem (HES) cell lines is highly problematic.
- one problem is that they are dependent on human fertilized eggs to grow blastocysts. The inner cell mass is used to make the HES cell line. It is not easy to get fertilized eggs. In the UK you can't make fertilized eggs just for the purpose of making HES lines.
- Another problem is the success rate. Having successfully grown a blastocyst and isolated the inner cell mass (which are all not easy steps) the cells need to be cultured. That is difficult. They hardly ever do. He told a story that they once finally had isolated an inner cell mass of which the cells started to grow in vitro. Then you need to multiply the cells. They did it by letting the mass grow bigger and cutting it in 4 pieces. Each piece was put in a new dish and grown more. They did this a few times and then all cultures got contaminated. They lost it all. That doesn't sound like a big deal, but they had to wait for next succesful growth of an inner cell mass for another FULL YEAR!
- HES cells differentiate easily. He said they will start differentiating already if you give them a wrong look. You don't want to differentiate them prematurely, because you need to grow them in large quantities if you want to use them in therapy.
- HES cells can be induced to differentiate easily (which is an requirement if you want to used them in a controlled manner for regeneration therapy), BUT they never differentiate the same twice under the same conditions.
- HES cells are currently grown on feeder cell layers as are mouse embronic stem cells. The problem is that the feeder layer is made up of mouse fibroblasts. You cannot use the human stem cells for regeneration therapy if you grow them on mouse cells, or use any other products which have animal origin. That is a major problem because we don't know how yet.
- You would need to grow stem cells in bulk on an industrial scale. Unfortunately we are nowhere near. Not even close. The scaling up is a bigger problem than just using bigger tubes, because HES cells are so delicate and differentiate or die so easily.
maybe more later
The creation of human embryonic stem (HES) cell lines is highly problematic.
- one problem is that they are dependent on human fertilized eggs to grow blastocysts. The inner cell mass is used to make the HES cell line. It is not easy to get fertilized eggs. In the UK you can't make fertilized eggs just for the purpose of making HES lines.
- Another problem is the success rate. Having successfully grown a blastocyst and isolated the inner cell mass (which are all not easy steps) the cells need to be cultured. That is difficult. They hardly ever do. He told a story that they once finally had isolated an inner cell mass of which the cells started to grow in vitro. Then you need to multiply the cells. They did it by letting the mass grow bigger and cutting it in 4 pieces. Each piece was put in a new dish and grown more. They did this a few times and then all cultures got contaminated. They lost it all. That doesn't sound like a big deal, but they had to wait for next succesful growth of an inner cell mass for another FULL YEAR!
- HES cells differentiate easily. He said they will start differentiating already if you give them a wrong look. You don't want to differentiate them prematurely, because you need to grow them in large quantities if you want to use them in therapy.
- HES cells can be induced to differentiate easily (which is an requirement if you want to used them in a controlled manner for regeneration therapy), BUT they never differentiate the same twice under the same conditions.
- HES cells are currently grown on feeder cell layers as are mouse embronic stem cells. The problem is that the feeder layer is made up of mouse fibroblasts. You cannot use the human stem cells for regeneration therapy if you grow them on mouse cells, or use any other products which have animal origin. That is a major problem because we don't know how yet.
- You would need to grow stem cells in bulk on an industrial scale. Unfortunately we are nowhere near. Not even close. The scaling up is a bigger problem than just using bigger tubes, because HES cells are so delicate and differentiate or die so easily.
maybe more later