Hey you guys work with stem cells, right?

Here is a question I received from a friend asking about the differences between embryonic stem cells and induced pluripotent stem cells:

Questions: A friend of mine posted an article saying that embryonic stem cell research is useless because it can all be done with induced pluripotent stem cells. That seems incorrect to me. Could you give me some insight into this issue?

My Answer: Sure, you're right. Embryonic stem cells are NOT the same as induced pluripotent stem cells. This is a common statement that people (usually idiots who read newspaper headlines and don't bother to actually read the research). Also the reason for this could also be because the term "stem cell" is such a buzz word now and almost everything is called a stem cell. Lets review a few of the criteria for a "stem cell".

1. Immortality
Incorrect, stem cells are NOT immortal. They can generate many progenitor cells over their lifetime by assymetrical cell division, but they are by no means immortal.

2. Can form multiple cell types. This has really only been shown in vitro. So a "stem cell" is put into a media and then forms different cells. Not really been conclusively shown in vivo, and if it was conclusive in vivo, we'd have cured spinal cord injuries by now. Fact of the matter is, the way cells behave in vitro is not the same as how cells behave in vivo.

Also, certain "stem cells" only produce 1 type of cell. A muscle satellite cell is a stem cell, but it only produces only 1 cell type (muscle cells). But it is present in senescence and has the potential for many cell divisions.

3. Stem cells are special and other cells cannot normally become stem cells. There is evidence that liver cells can undergo a dedifferntiation following injury/loss of regions of the liver.

In terms of ES vs. iPS cells:

ES and iPS cells are similar yes, but NOT THE SAME. ES cells come from 5-6 day old embryos after in vitro fertilization. These cells can turn into all cells of the body. iPS cells come from adult cells that are reprogrammed to "act" like embryonic stem cells. I believe you can activate 4 specific genes that can "reprogram" an adult cell to an iPS cell. They can also form all cells of the body.

But the issues arise when we look at the methods of creating iPS cells. The methods vary between labs, the cells produced by different labs behavior differently, and simply, comparing ES and iPS cells on a genetic level shows that DIFFERENT GENES ARE ACTIVATE between ES and iPS cells. For example recently, European and Israeli researchers found that when they created iPS and ES cells both containing a mutation that causes fragile X syndrome, the two groups of cells behaved very differently, with the iPS cells not even activating the mutated gene (FMR1). It is possible (if not very likely) that other genes may likewise escape the reprogramming process leading to iPS cells.