Archive for the ‘stem cell & regeneration’ Category

This is a collection of the videos that I used in lab discussion section of the ethical issues in human embryonic stem cells research in the 2014 BIOL36701 Principles Development at Purdue University.

1. An introduction to stem cell – A stem cell story

2. Are embryos persons?

3. A question of balance?

4. How patients may be exploited – Stem cell fraud

5. hESCs alternative I – Stem cells – the future: an introduction to iPS cells

6. hESCs alternative II – STAP cells

An interesting study have reported a way that may potential help people who suffer from spinal cord injury.

From the New York Times, “In Rat Experiment, New Hope for Spine Injuries“:

Rats with a spinal cord injury that left their hind legs completely paralyzed learned to walk again on their own after an intensive training course that included electrical stimulation of the brain and the spine, scientists reported on Thursday.

Adopted from the New York Times; Source: École Polytechnique Fédérale de Lausanne

Reference

van den Brand R, Heutschi J, Barraud Q, DiGiovanna J, Bartholdi K, Huerlimann M, Friedli L, Vollenweider I, Moraud EM, Duis S, Dominici N, Micera S, Musienko P, Courtine G. Restoring voluntary control of locomotion after paralyzing spinal cord injury. Science. 2012 Jun 1;336(6085):1182-5. PubMed PMID: 22654062.


				

In my last post, I provided several links to general introductions of stem cells. In this post, I will share several documentaries that show how bad people are taking advantage of desperate patients who have heard stem cells therapy may give them a last hope.

II. Desperate patients and people who take advantage of their situation

1. BBC Panorama – Stem Cells & Miracles (2009)

(2015-02-22) Youtube.com has taken this BBC video off from their site.

2. CBS 60 Minutes – Stem Cell Snake Oil (2010)

 

This is part 1 of the show; here are the links to part 2, part 3 and part 4.

3. CBS 60 Minutes – Stem cell fraud (2012)

Youtube link

CBS link

There is an interesting news article “Printing Muscle” from Technology Review about using 3-D printers to print muscle cells so that they may assume a 3-D shape that resembles muscle fiber. The idea sounds interesting, because one can potentially print tissues or even organs that have complicated cellular composition in 3-D for regenerative medicine.

 

Over the years, I have been leading a discussion about the ethical and social issues of stem cells research in my class and have used a few useful videos on various aspects. You may find them useful too.

I. Introduction to the topic

References

Here are two recent scientific references that give the current status of iPSCs research and compared that with hESCs, as well as the challenges ahead in research and ethical issues.

  1. Robinton DA, Daley GQ. The promise of induced pluripotent stem cells in research and therapy. Nature. 2012 Jan 18;481(7381):295-305. PubMed PMID: 22258608.
  2. Hug K, Hermerén G. Do we still need human embryonic stem cells for stem cell-based therapies? Epistemic and ethical aspects. Stem Cell Rev. 2011 Nov;7(4):761-74. PubMed PMID: 21461713.

This reference is a general scientific review on various ways that one can reprogramming cells that may potentially be used for therapeutic purposes.

  1.  Gurdon JB, Melton DA. Nuclear reprogramming in cells. Science. 2008 Dec 19;322(5909):1811-5. Review. PubMed PMID: 19095934.

From Washington Post:

For the first time, an experimental treatment made from human embryonic stem cells has shown evidence of helping someone, partially restoring sight to two people suffering from slowly progressing forms of blindness.

In short, the authors of this study that is just published in Lancet differentiated human embryonic stem cells (hESC) into retinal pigment epithelium (RPE), a key eye tissue that is often affected in retinal degeneration. Then, they transplanted these RPE cells into two patients suffering from Stargardt’s disease and age-related macular degeneration. The purpose of the trial was to find out whether this procedure is safe. Interestingly, there was a pleasant surprise that both patients seem to have some improvements in eye sight. While there is still a lot to do before stem cells therapy will become widely applicable as a general treatment, this finding is an encouraging first sign.

Reference

Embryonic stem cell trials for macular degeneration: a preliminary report [Lancet][pdf]

Today there is an article published in CELL about the generation of chimeric monkey. Unlike the traditional way for generation of chimeric mouse for making transgenic animal that can utilize pluripotent stem cells or inner cell mass, the process in primates requires the usage of totipotent cells at a much earlier stage – 4-cell stage. The authors could aggregate these early embryos and generate chimera. See a simple and good news coverage from the BBC for further discussions of the importance.

Adopted from the journal website

References

  1. Tachibana M, Sparman M, Ramsey C, Ma H, Lee HS, Penedo MC, Mitalipov S. Generation of Chimeric Rhesus Monkeys. Cell. 2012 Jan 4. [Epub ahead of print] PubMed PMID: 22225614.
    • Commentary: Trounson A, Grieshammer U. Chimeric Primates: Embryonic Stem Cells Need Not Apply. Cell. 2012 Jan 4. [Epub ahead of print] PubMed PMID: 22225613.

From Discover magazine: “Helpful Mouse Fetuses Naturally Send Stem Cells to Mom to Fix Her Damaged Heart”

The punchline is

When a pregnant mouse has a heart attack, her fetus donates some of its stem cells to help rebuild the damaged heart tissue.

The original article is available here.

Kara RJ, Bolli P, Karakikes I, Matsunaga I, Tripodi J, Tanweer O, Altman P, Shachter NS, Nakano A, Najfeld V, Chaudhry HW. Fetal Cells Traffic to Injured Maternal Myocardium and Undergo Cardiac Differentiation. Circ Res. 2011 Nov 14. [Epub ahead of print] PubMed PMID: 22082491.

We have briefly touched the subject of stem cell research in the last journal club. The challenge of developing “stem cell” as a useful therapy is three fold:

  1. Turning the clock of a differentiated cell back to the very beginning.
  2. Guiding the resulting dedifferentiated “stem cells” or any kinds of “stem cells” to develop into the appropriate cell types.
  3. Incorporating these new cells into the existing organ system properly.

In one sense, the premise of 1 and 2 is that 3 would happen automatically once you can get the Stem cells. They are not only expected to become the desired cell type, but also are expected to know what to do inside the body. This can be a tall order.

There is actually a lot to learn from basic research to see how mother nature deals with the regeneration problem. Salamander is a great regeneration model. If you cut its limb off, the cells in the wound region will grow back a limb to its entirety.

It has long been thought that these cells that are responsible for the regeneration process are pluripotent, or “stem cell”-like. A very interesting research has proven it is otherwise. The original cells in the limb actually remember their identities, and they will only grow back to their own kind. In other words, muscle cells will become muscle cells, and skin cells will become skin cells.

460039a-f2.2

It looks like that instead of having some very specialized stem cells that switch all the way  back to the beginning, the differentiated cells just go back a few (?) steps and maintain their identities during the process. One wonders how this process is regulated at the network level and what has been lost in us that we do not have this capability anymore. Maybe this talent is still hibernating somewhere in our genome, waiting for us to turn it back on.

References:

Sánchez Alvarado A. A cellular view of regeneration. Nature. 2009 Jul 2;460(7251):39-40. [PubMed][Nature]

Kragl M, Knapp D, Nacu E, Khattak S, Maden M, Epperlein HH, Tanaka EM. Cells keep a memory of their tissue origin during axolotl limb regeneration. Nature. 2009 Jul 2;460(7251):60-5. [PubMed][Nature]