Stem cells derived from amniotic fluid and placenta

Published on March 5, 2014   30 min
0:00
This is Anthony Atala from the Wake Forest Institute for Regenerative Medicine in Winston-Salem, North Carolina. And I will be discussing the topic of stem cells derived from amniotic fluid and placenta.
0:16
The amniotic fluid is the fluid that surrounds the developing embryo and fetus, and the placenta is a tissue that surrounds both the developing embryo and fetus as well as the fluid. Interestingly, both of these sources, the fluid and the tissue, are present all the way until the time that the baby is delivered.
0:42
Both the amniotic fluid and the placenta can be obtained any time after a certain period, during gestation, all the way through term. Amniocentesis is a procedure where amniotic fluid gets obtained anywhere between 14 weeks of gestation all the way through term. And that is where we obtain the amniotic fluid. Chorionic villus sampling is a procedure where we obtain a small piece of a placenta any time between 12 weeks through term. Both techniques are widely accepted methods for the prenatal diagnosis of the fetus or the embryo, and it can be done all the way through the time of birth. It is well known that both amniotic fluid and the placenta are full of the developing fetus cells. However, what we postulated about 10 years ago, whether these sources could in fact be a possible source for stem cells.
1:44
In a series of studies, we started obtaining both amniotic fluid and placental-derived stem cells. We ended up doing this by taking either fresh cells from amniocentesis or fresh cells from chorionic villus sampling, or we were taking cells from the back-up cytogenetics cultures that were being performed for prenatal diagnosis. Once we grew and expanded these cells, we were able to do a c-Kit isolation of the cells. And we were able to establish clonal cell lines, which were grown without feeder layers.
2:24
In this manner, we were able to obtain over 400 human amniotic fluid and placental cells. We were able then to harvest the cells, expand them, do a c-Kit isolation, and we were then able to differentiate the cells to many different tissue types, representing all three germ layers.
2:46
Once we were able to expand these cells in large quantities, we started doing clonal studies, and clonality was confirmed by Southern blot showing retroviral insertion fingerprints. We were able to show that one cell, and one cell alone, could be differentiated into three different germ layers. The retroviral insertion fingerprint showed the insertion at the same location in each cell line, showing that all the cells were derived from the same one clonal cell.
3:18
In a series of studies looking at the telomere length, we were able to show that the stem cells were able to preserve their telomere length. This was important, as we were able to show that the cells had a high doubling time. They would double in number every 36 hours, in a very similar fashion to human embryonic stem cells.
3:42
Using flow cytometry and immunocytochemical studies, we were able to show that the cells had markers consistent with human embryonic markers, such as SSEA-4, OCT4, and SOX2.
3:59
Up to this point, we were able to show that the cells were clonal, that the cells preserved their telomere length, and that the cells had early markers of pluripotency, all consistent with human embryonic stem cells. But interestingly, the cells also had markers consistent with adult stem cells.
4:20
The cells show that they had markers such as CD105, CD073, CD146, and other markers, again, consistent with adult stem cells.
4:34
We performed an expression profile analysis of the "stemness genes" using embryonic stem cells, induced pluripotent stem cells, adult bone marrow mesenchymal stem cells, and amniotic fluid and placental-derived stem cells. We were able to show that the amniotic fluid and placenta-derived stem cells had a much higher similarity to both embryonic and induced pluripotent stem cells than the adult bone marrow stem cells. So the amniotic fluid placental stem cells were much more closely related to the early human embryonic and iPS cells.
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Stem cells derived from amniotic fluid and placenta

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