Posts Tagged ‘stem cells’

But are they really pluripotent?

 :: Posted by American Biotechnologist on 03-09-2011

Scripps Research Scientists Develop New Test for “Pluripotent” Stem Cells

The diagnostic test enables accurate, rapid assessment of the quality of stem cell lines

LA JOLLA, CA – “Pluripotent” stem cells—which have the potential to mature into almost any cell in the body—are being widely studied for their role in treating a vast array of human diseases and for generating cells and tissues for transplantation. Now, a team of Scripps Research Institute scientists has created a quality control diagnostic test that will make it much easier for researchers to determine whether their cell lines are normal pluripotent cells.

The study was published in an online version of Nature Methods on March 6, 2011.

“Many scientists are unhappy with the current gold standard for testing for pluripotency, called the teratoma assay,” said Scripps Research molecular biologist Jeanne Loring, principal investigator of the study. “The teratoma assay requires animal testing and a time span of six to eight weeks before scientists can prove that they have a pluripotent stem cell line. In addition, this method is technically challenging and difficult to standardize.”

The new test, called “PluriTest,” meets the need for a cost-effective, accurate, animal-free alternative to the teratoma assay for assessing pluripotency. Using microarray technology, which enables the simultaneous analysis of thousands of different DNA sequences, the Scripps Research team created a large database of information about all the genes that are active in hundreds of normal human embryonic and induced pluripotent stem cells and a variety of non-pluripotent cell lines. For PluriTest, this database was used to create a detailed molecular model of a normal pluripotent stem cell line.

“Unlike diagnostic tests that use small sets of biomarkers to examine cells, the molecular model approach uses all of the thousands of pieces of information in a microarray,” Loring said. “This results in a diagnostic test with remarkable sensitivity and specificity.” Scientists upload raw data straight from a single microarray analysis to the PluriTest website and learn within 10 minutes whether their cell line is pluripotent.

An additional feature of the PluriTest diagnostic test is that it can show whether a cell that is pluripotent is different in some way from the normal model pluripotent cell line. For example, a “novelty score” generated by the software may indicate that the pluripotent cells have genomic aberrations such as extra copies of genes or chromosomes. This feature would alert the researcher to do additional analysis on the cells to determine what is causing the abnormality.

A first author of the study, Franz-Josef Mueller, said, “Scientists are making new induced pluripotent stem cell lines at a rapid pace to understand human disease, test new drugs, and develop regenerative therapies. Thousands of induced pluripotent stem cell lines have already been generated and soon there will be many more thousands. PluriTest is designed to enable the growth of this technology.”

Reference:
Müller FJ, Schuldt BM, Williams R, Mason D, Altun G, Papapetrou EP, Danner S, Goldmann JE, Herbst A, Schmidt NO, Aldenhoff JB, Laurent LC, & Loring JF (2011). A bioinformatic assay for pluripotency in human cells. Nature methods PMID: 21378979

Source: Scripps Institute

Regenerating body parts one limb at a time

 :: Posted by American Biotechnologist on 02-08-2011

If an injured salamander can grow a new limb, why can?t a human? Maybe they can, say researchers at the Armed Forces Institute of Regenerative Medicine.

Starting with cells from patients bodies, scientists at this Wake Forest University facility have grown 22 different types of tissues and organs. Lives are being saved and more amazing successes are on the way.

The science fiction of yesterday happens to be a lot of the medicine of today, says Anthony Atala, MD the Institutes co-director. It is the imagination that allows us to seek these solutions that someday in the future become a reality.

Shout out to GrrlScientist for pointing out this video. Great find!

Converting skin cells to beating heart cells in just 11 days

 :: Posted by American Biotechnologist on 01-31-2011

Scripps Research Institute scientists have converted adult skin cells directly into beating heart cells efficiently without having to first go through the laborious process of generating embryonic-like stem cells. The powerful general technology platform could lead to new treatments for a range of diseases and injuries involving cell loss or damage, such as heart disease, Parkinson’s, and Alzheimer’s disease.

The work was published January 30, 2011, in an advance, online issue of Nature Cell Biology.

“This work represents a new paradigm in stem cell reprogramming,” said Scripps Research Associate Professor Sheng Ding, Ph.D., who led the study. “We hope it helps overcome major safety and other technical hurdles currently associated with some types of stem cell therapies.”

The advantages of producing heart cells directly from skin cells while circumventing the normal route of reprogramming them first into induced pluripotent stem cells (iPS) include:

  • saving the 2 to 4 weeks needed for the iPS reprogramming step
  • saving 2 to 4 weeks needed to convert the iPS cells into heart cells
  • avoiding the chance that undifferentiated iPS cells remain with the potential of becoming cancerous later on
  • going from skin cells to beating heart cells in a dish in just 11 days
  • The converted skin cells beat much like seen in the video below. However, unlike the video which shows reprogrammed adult cells that have become beating heart tissue, the team introduced the same four genes initially used to make iPS cells into adult skin fibroblast cells, but instead of letting the genes be continuously active in cells for several weeks, they switched off their activities just after a few days, long before the cells had turned into iPS cells. Once the four genes were switched off, the scientists gave a signal to the cells to make them turn into heart cells.

    (Video Citation: “Functional Cardiomyocytes Derived from Human Induced Pluripotent Stem Cells.” By Jianhua Zhang, Gisela F Wilson, Andrew G Soerens, Chad H Koonce, Junying Yu, Sean P Palecek, James A Thomson, and Timothy J Kamp. Circulation Research, Vol. 104 No. 3, Feb. 12, 2009.)

    For a great tool on stem cells, be sure to download the Stem Cell Guide for Life Science Reserchers from Bio-Rad Laboratories.

    Click here to read the full press release from the Scripps Research Institute.

Stem Cell Rap

 :: Posted by American Biotechnologist on 07-22-2010

Check out this awesome video that will put a smile on your face. Thanks to The Translational Biology Blog for sharing and to my twitter friend @sciencegoddess for bringing it to my attention!

Should Life Saving Research be Stymied by Legalese?

 :: Posted by American Biotechnologist on 06-27-2010

Although the debate rages on regarding the use of embryonic stem cells in medical research, the Obama administration has loosened the government’s grip on stem cell regulation resulting in a 3-fold increase in the number stem cell lines approved for federal research funding.

That is why it is particularly disturbing when the USA Today and Nature News report that the NIH has turned down federal approval for the introduction of 47 embryonic stem cell lines submitted by the Reproductive Genetics Institute (RGI), a
world-renowned provider of fertility treatments including InVitro Fertilization (IVF), Preimplantation Genetic Diagnosis (PGD), and prenatal diagnosis. RGI routinely removes an embryonic stem cell from the embryo for genetic testing and if the embryo is found to carry an inheritable disease, it is not implanted into the patient. As such, RGI is routinely left with embryos that carry genes for various illnesses and whose fate would likely be the wastebasket if they cannot be used for medical research. Certainly sounds like a waste of “potential life” to me. And so, RGI asks patients to sign forms that give consent for “leftover” embryos to be used in medical research and then submits a request to the NIH for federal approval to use these cells in medical research. Cell lines that are not approved by the NIH will not be able to receive federal funding for their research.

So far so good. However, the NIH recently rejected 47 cell lines, not for reasons that we might usually associate with normative medical ethics, rather, the cell lines were rejected because of legal gobbledygook (don’t get me wrong…some of my closest friends are lawyers). The gobbledygook was clarified by the NIH as follows:

“The ACD recommended against approving the lines based on findings of the Working Group under Section IIB of the NIH Guidelines, due primarily to exculpatory language in the consent form for the donation of embryos for research. This use of exculpatory language (when someone is asked to give up or waive any rights they may have) was inconsistent with the basic ethical principle of voluntary consent.”

Huh?

OK, well let’s try to explain. According to the USA Today the “exculpatory” language in the consent form absolved the lab of legal liability for any harm that might come to donors from their donation, forbidden in consent forms by federal rules. Does that make sense? Well…I guess that kind of…slippery slope…transparency…the law should be equally applied to everyone…credibility of the NIH…

BUT…we’re talking about 47 cell lines. 47 wasted embryos. 42 embryos that contained genetic information for debilitating diseases such as Cystic fibrosis, Duchene’s muscular dystrophy and Huntington’s disease. Holy cow! Imagine the information that could have been gleamed from these cells. Imagine the mechanisms of disease that could have been revealed. The government was on board. The cells were in our hand. And along came the legal system….

I’m frustrated. The CEO of RGI has told Nature that he tried to contact the consenting couples to get their signatures but the referring physicians refused to give him the patient’s contact information. RGI’s CEO calls the situation a “nightmare” and I tend to agree.

Don’t you?