The newest tool in the regenerative medicine box.

Blog entry

The new kid on the stem cell block has a lot of people talking. It has been touted as the next best thing in regenerative medicine (rightfully so). What’s the deal? Well, for starters, they don’t start off as stem cells at all. These Induced Pluripotent Stem Cells start off as a fully mature adult cell types, such as skin fibroblasts. They are then transfected with the genes known to maintain the pluripotent state in embryonic stem (ES) cells. This, in effect, pushes the cells to re-discover and maintain the qualities of ES cells.Also, it seems to have bypassed the ethical issues that surround the derivation of ES cells.
The first iPS cells were generated using mouse cells and a year later, two separate labs, one in the US and one in Japan, developed the first human iPS cell lines. Without getting into too much detail (believe it or not, Wikipedia goes into some pretty good detail if you’re up for some light reading), I’ll tell you that the two labs used a slightly different mix of genes to generate the human iPS cells. Shinya Yamanaka and colleagues used Oct3/4, Sox2, Klf4, and c-Myc to generate their human iPS cells, while Jamie Thompson and his lab used Oct3/4, Sox2, Nanog, and LIN28.  Following these reports, Yamanaka then reported that c-myc could be completely left out of the recipe. Both methods have been shown to be successful by others. However, as you may very well guess, scientists hold differing opinions on which one works better.

OK, so now that we have iPS cells, how do we care for them? Essentially, human iPS cells can be grown just like human ES cells:  They’re typically grown in the presence of a feeder layer, ES-grade serum (or KSR) and FGF2, non-essential amino acids, and BME. They can also be put under the same conditions used to drive differentiation of human ES cells. This is where the regenerative medicine folks start licking their chops…

The clinical endpoint that we all hope to see for iPS cells is this: Treatment of degenerative diseases using a patient’s own cells. The idea is that you can go to the hospital, get a skin biopsy and have those cells sent off to be turned into iPS cells. Then, these iPS cells can be treated in culture to make the cells that your body needs. Imagine your skin cells being used to make brain cells, white blood cells, cardiomyocytes and then having them injected into you, to fix you. Pretty cool, in my book.

Now, don’t go off thinking your organs can be grown in a lab. There are still plenty of limitations to overcome. For example, these cells are pretty good at making tumors. Your new healthy heart will do you no good if you have iPS-induced cancer. Another limitation is efficiency. It’s not easy to make these cells, and the ones that are made don’t always behave the way you might want them to.  Also, of no less importance is this business of not really knowing where your vectors are inserting themselves into the cells’ genome. There’s always a possibility that the insertion of one of these iPS genes can induce unwanted mutations in the cells, leading to things like tumor formation, or even inability of the cells to function.

The good news is that there are many, very talented scientists working on these problems and the good folks at Gemini want to be there to lend a hand…..or maybe an engineered protein. They have a pretty impressive portfolio of recombinant proteins like bFGF (FGF2) for your iPS cells…Not to mention proteins you can use to drive differentiation or maintain your progenitor populations (like BDNF, VEGF, PDGF, M-CSF, to name a few). I just went to their website and found out that a quick search for “factor” turns up at least 60 different products.  Maybe they have yours…..Maybe they work better than the ones you’re using now…Maybe at better prices. Never hurts to ask!


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