Skip to comments.New Stem Cell Technique Promises Abundance of Key Heart Cells
Posted on 05/29/2012 4:35:53 PM PDT by neverdem
Cardiomyocytes, the workhorse cells that make up the beating heart, can now be made cheaply and abundantly in the laboratory.
Writing this week (May 28, 2012) in the Proceedings of the National Academy of Sciences, a team of Wisconsin scientists describes a way to transform human stem cells -- both embryonic and induced pluripotent stem cells -- into the critical heart muscle cells by simple manipulation of one key developmental pathway. The technique promises a uniform, inexpensive and far more efficient alternative to the complex bath of serum or growth factors now used to nudge blank slate stem cells to become specialized heart cells.
"Our protocol is more efficient and robust," explains Sean Palecek, the senior author of the new report and a University of Wisconsin-Madison professor of chemical and biological engineering. "We have been able to reliably generate greater than 80 percent cardiomyocytes in the final population while other methods produce about 30 percent cardiomyocytes with high batch-to-batch variability."
The ability to make the key heart cells in abundance and in a precisely defined way is important because it shows the potential to make the production of large, uniform batches of cardiomyocytes routine, according to Palecek. The cells are in great demand for research, and increasingly for the high throughput screens used by the pharmaceutical industry to test drugs and potential drugs for toxic effects.
The capacity to make the heart cells using induced pluripotent stem cells, which can come from adult patients with diseased hearts, means scientists will be able to more readily model those diseases in the laboratory. Such cells contain the genetic profile of the patient, and so can be used to recreate the disease in the lab dish for study. Cardiomyocytes are difficult or impossible to obtain directly from the hearts of patients and, when...
(Excerpt) Read more at sciencedaily.com ...
Human pluripotent stem cells (hPSCs) offer the potential to generate large numbers of functional cardiomyocytes from clonal and patient-specific cell sources. Here we show that temporal modulation of Wnt signaling is both essential and sufficient for efficient cardiac induction in hPSCs under defined, growth factor-free conditions. shRNA knockdown of β-catenin during the initial stage of hPSC differentiation fully blocked cardiomyocyte specification, whereas glycogen synthase kinase 3 inhibition at this point enhanced cardiomyocyte generation. Furthermore, sequential treatment of hPSCs with glycogen synthase kinase 3 inhibitors followed by inducible expression of β-catenin shRNA or chemical inhibitors of Wnt signaling produced a high yield of virtually (up to 98%) pure functional human cardiomyocytes from multiple hPSC lines. The robust ability to generate functional cardiomyocytes under defined, growth factor-free conditions solely by genetic or chemically mediated manipulation of a single developmental pathway should facilitate scalable production of cardiac cells suitable for research and regenerative applications.
“a way to transform human stem cells — both embryonic and induced pluripotent stem cells”
What is the source of these “embryonic” cells?
Fertilized eggs from the usual, objectionable suspects, IMHO. But there's a problem with induced pluripotent stem cells because they have seen the effects of epigenetic imprinting upon them since they were originally adult somatic cells before they were induced pluripotent stem cells.
Even though there is an obvious potential for immunological differences between induced pluripotent stem cells and embryonic stem cells, because of these epigenetic changes embryonic stem cells have been proposed as the reference or control group in regenerative medicine experiments with induced pluripotent stem cells, IIRC.
It's not that I approve of this methodology. Could they use chimp embryonic stem cells instead? I don't know. This is the path they have chosen for a control group. I'm not doing the experiments. I just posted a press release.
If they acquire useful medical knowledge about human induced pluripotent stem cells is another question. What if you had a patient or a family member that could benefit from this knowledge that human induced pluripotent stem cells have been validated for the purpose of therapeutic regenerative medicine? Folks without these ethical qualms are doing these experiments. Should their results be ignored?