Embryonic and Induced Pluripotent Stem Cells Have Genetic Problems
POSTED ON 1/7/2011 IN Research BY Christopher Centeno
You know the saying, "there is no free lunch"? Well, several recent studies have rained on the parade of the embryonic stem cells and IPS crowd. A recent piece in the LA times quoting a paper published this week was more percipitation. The problem is that these cell lines have inherent genetic problems. This means that the cells don't have normal genes, which raises the specter of unintended consequences when these cells are used for therapy (the biggest being cancer). The reason should be clear by now. Embryonic stem cells (or likely even adult stem cells) that are "immortalized" (artificially tricked into growing forever so that they can be mass produced like an antibiotic) pick up these genetic abnormalities because these cells were never designed by nature to have the DNA repair mechanisms that would allow them to be grown for these great lengths of time. For example, everyday, dividing cells in your body pick up back pieces of DNA or errors. We have enzymes that help repair the damage and a secondary line of defense (called the immune system) to yank the malfunctioning cells out of circulation. However, embryonic (or even adult stem cells) were never designed with the mechanisms to be grown for thousands of generations. An embryo is conceived, it grows bigger, and eventually a baby with adult stem cells is born. Nowhere in there was the embryo designed to grow embryonic stem cells for years for the purposes of satisfying a human need for mass produced biologic tissue. How about IPS cells? For those of you who are unaware, IPS means induced pluripotency, which is a fancy way of saying that a normal adult cell is turned into a cell that resembles an embryonic stem cell. Now since this doesn't even happen in nature, the process of tricking a cell to revert back to the properties of a stem cell is bound to have issues (which many IPS researchers have been very honest about from the start). Again, since normal adult cells aren't built to divide forever like IPS cells, the same discussion above applies. If you're seeing a trend here, you're not the only one. In both instances, it's our need to create cells that can be mass manufactured to satisfy a business model that creates the problem. How about adult stem cells like those used in the Regenexx procedure family? Adult stem cells are built to do what we're asking them to do. They help repair tissue and then either differentiate into the bricks and mortar of the repair or they orchestrate the construction job and then disappear from the scene. Growing adult stem cells for short periods (like in the Regenexx-C procedure), still keeps the cells within the parameters of what happens in the body. Studies have shown no significant genetic abnormalities when adult stem cells are grown for short periods and more interestingly, when they are grown very long periods (months and months) and do pick up genetic abnormalities, they don't form cancers, they just don't work anymore. Our complications tracking data has also shown that using these short-term cultured stem cells in people poses less risks than the surgical procedures they help many patients avoid. This is consistent with the findings of others showing robust safety for cultured adult stem cells from bone marrow. In summary, you can't teach an old dog new tricks (I think that's my third really bad turn of phrase). Trying to mass produce cells isn't a good idea with our current state of knowledge. A better idea is using the patient's own adult stem cells, which is the "customized" medicine long sought by physicians. While the business model may not be as good, it's sure a heck of a lot safer for the patient.
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