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Cloned stem cells offer high fidelity

Posted: July 5, 2014 at 4:52 pm

OHSU, Center for Embryonic Cell and Gene Therapy

Human embryonic stem cells made via nuclear transfer, also known as cloning.

Scientists have established two ways to take differentiated cells from one person and generate stem cells capable of forming all cell types in the body most recently by cloning. Research published today in Nature1 compares genetically identical human stem cells made by different techniques and reveals differences in gene expression that might be important for medical research and for cell therapies.

Pluripotent stem cells can produce large supplies of, say, neurons or heart muscle, so are valuable for studying diseases and, potentially, for treating them. Human pluripotent stem cells were first made2 in 1998 from embryos left over from fertility treatments, and pluripotent stem cells produced by this method are still considered the gold standard because there is no question that embryos can produce all types of tissue in the body.

The newer techniques, called nuclear transfer and genetic reprogramming, can use cells from living people to make pluripotent stem cells that are genetically matched to a patient. For research purposes, matching provides cells from people whose disease history is known. For therapies, matching means that cells are more likely to be suitable for therapies.

Last year, Shoukhrat Mitalipov, a cell biologist at the Oregon Health and Science University in Portland, and his colleagues became the first to produce human pluripotent stem cells using nuclear transfer3, a technique also known as cloning. They took the nucleus from a cultured skin cell, placed it in an unfertilized egg that had had its nucleus removed, then made embryonic stem (ES) cells from the resultant embryo.

In the paper published today, Mitalipov and his collaborators compared cloned ES cells to 'induced pluripotent' stem (iPS) cells made by inserting reprogramming genes into cells from the same batch of cultured skin cells used to make the cloned ES cells.

In neither case did the genetic material return fully to an embryonic-like state, says Mitalipov, but one technique was the clear winner. Nuclear transfer doesn't do a perfect job of resetting, but in general it does a very, very good job in relation to iPS reprogramming.

To measure the relative quality of the two types directly, they saw how they measured next to the 'golden standard' of cells from discarded embryos by looking at their patterns of methylation, a type of 'epigenetic' modification of DNA, meaning that it affects gene expression without changing the underlying gene sequences.

Methylation patterns of nuclear-transfer ES cells were closer to those from fertilized eggs than were methylation patterns in iPS cells. More than 1,200 genes were expressed differently in the three cell types; most of these differences, about 65%, were between iPS cells and the two types of ES cells. These differences, says Mitalipov, could mean that ES cells from nuclear transfer are better able than iPS cells to mature into other cell types.

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Cloned stem cells offer high fidelity

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Scientists regenerate teeth using shark stem cells – Video

Posted: July 5, 2014 at 1:50 pm


Scientists regenerate teeth using shark stem cells
Experimental procedure to correct tooth loss for accident victim Joe Howard results in tooth regeneration. Clip from documentary film Pandora #39;s Hope by Kit F...

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Scientists regenerate teeth using shark stem cells - Video

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What stem cell treatments (advertised elsewhere) can you recommend? – Video

Posted: July 5, 2014 at 1:50 pm


What stem cell treatments (advertised elsewhere) can you recommend?
HSCI Kidney Program Leader Benjamin Humphreys, MD, PhD, at Brigham and Women #39;s Hospital answers patient frequently asked questions. (Video 2 of 4) More about stem cell tourism: http://www.closerlo...

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Embryonic Stem Cells & their Controversy (unbiased view) – Video

Posted: July 4, 2014 at 11:48 am


Embryonic Stem Cells their Controversy (unbiased view)
This video discusses what stem cells are and why their research is a divisive issue in today #39;s society. I use this video in my biology class at Beverly Hills...

By: Kyle Kobe

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Embryonic Stem Cells & their Controversy (unbiased view) - Video

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A vote for stem cells – Video

Posted: July 4, 2014 at 11:48 am


A vote for stem cells
The $3 billion California Institute for Regenerative Medicine, the world #39;s largest stem cell research agency, is funded by the state - not the federal govern...

By: nature video

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Can stem cells really restore your youthful looks?

Posted: July 4, 2014 at 12:47 am

When an aging Hollywood action star or sex symbol reemerges after a long hiatus looking younger, with a great body and smoother, firmer facial skin, people now assume they have undergone stem cell therapy.

In my interview with doctors Eric and Anna Yalung of Regenestem Manila, they set me straight. While the actor/actress may have had stem cell therapy, the outward appearance is most likely a combination of Botox, plastic surgery, a strict diet and a personal trainer. So no doctor who only offers you stem cell can promise you outwardly beautifying results.

This is not to say though that there are no beauty benefits from it. For the beauty aspect, they do this for facial skin rejuvenation and hair growth. According to head dermatologist Anna Yalung, they inject the target area and, if necessary, combine it with services available at the clinic for best results and to speed up the process.

Shots are spaced a week to a month apart depending on treatment requirement for three sessions. The follow-up is scheduled the following year.

How is it done? Platelet Rich Plasma (PRP) is a convenient and cell-based treatment. It is a simple procedure involving the extraction of blood, separation of platelets and administering the PRP to the desired area.

This is done in order to stimulate or promote healing, collagen synthesis for anti-aging, or to deliver proper oxygenation to muscles or tissues. A crucially important function of platelets is the release of various growth factors responsible for almost all repair processes that occur in the body.

Dr. Eric Yalung, who has conducted PRP treatments with Dr. Joseph Purita, world-renowned pioneer in stem cell orthopedic surgery, will spearhead PRP therapy for arthritis, sports injuries, anti-aging, hair growth, facial rejuvenation and pain management. Yalung clears that it is not a cure-all. It wont make you thinner or outwardly younger by itself. Its main purpose is improving the quality of ones life and the highest success rates are for those who are suffering from osteoarthritis; degenerative diseases like diabetes, multiple sclerosis, Parkinsons and Alzheimers; sports injuries and pain management.

Regenestems team of four physicians do not work with embryonic stem cells, only with adult stem cells. Adult stem cells are found in all tissues of the growing human being and, according to latest reports, also have the potential to transform themselves into practically all other cell types, or revert to being stem cells with greater reproductive capacity.

The clinic also provides the option for patient treatments in Regenestem clinics worldwide (US, Mexico, Argentina, and Dubai), and includes assistance in hotel and travel plans.

Regenestem Manila is at 2/F, Belson House, 271 Edsa, Mandaluyong City; tel. 2452200. Visit http://www.regenestemasia.com

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Can stem cells really restore your youthful looks?

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Schizophrenia-associated gene variation affects brain cell development

Posted: July 3, 2014 at 9:45 pm

PUBLIC RELEASE DATE:

3-Jul-2014

Contact: Shawna Williams shawna@jhmi.edu 410-955-8236 Johns Hopkins Medicine

Johns Hopkins researchers have begun to connect the dots between a schizophrenia-linked genetic variation and its effect on the developing brain. As they report July 3 in the journal Cell Stem Cell, their experiments show that the loss of a particular gene alters the skeletons of developing brain cells, which in turn disrupts the orderly layers those cells would normally form.

"This is an important step toward understanding what physically happens in the developing brain that puts people at risk of schizophrenia," says Guo-li Ming, M.D., Ph.D., a professor of neurology and neuroscience in the Johns Hopkins University School of Medicine's Institute for Cell Engineering.

While no single genetic mutation is known to cause schizophrenia, so-called genomewide association studies have identified variations that are more common in people with the condition than in the general population. One of these is a missing piece from an area of the genome labeled 15q11.2. "While the deletion is linked to schizophrenia, having extra copies of this part of the genome raises the risk of autism," notes Ming.

For the new study, Ming's research group, along with that of her husband and collaborator, neurology and neuroscience professor Hongjun Song, Ph.D., used skin cells from people with schizophrenia who were missing part of 15q11.2 on one of their chromosomes. (Because everyone carries two copies of their genome, the patients each had an intact copy of 15q11.2 as well.)

The researchers grew the human skin cells in a dish and coaxed them to become induced pluripotent stem cells, and then to form neural progenitor cells, a kind of stem cell found in the developing brain.

"Normally, neural progenitors will form orderly rings when grown in a dish, but those with the deletion didn't," Ming says. To find out which of the four known genes in the missing piece of the genome were responsible for the change, the researchers engineered groups of progenitors that each produced less protein than normal from one of the suspect genes. The crucial ingredient in ring formation turned out to be a gene called CYFIP1.

The team then altered the genomes of neural progenitors in mouse embryos so that they made less of the protein created by CYFIP1. The brain cells of the fetal mice turned out to have similar defects in structure to those in the dish-grown human cells. The reason, the team found, is that CYFIP1 plays a role in building the skeleton that gives shape to each cell, and its loss affects spots called adherens junctions where the skeletons of two neighboring cells connect.

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Nuclear Transfer Proven An Effective Method In Stem Cell Production

Posted: July 3, 2014 at 9:42 pm

July 3, 2014

redOrbit Staff & Wire Reports Your Universe Online

A new process known as somatic cell nuclear transfer is far better and much more accurate when it comes to coaxing embryonic stem cells out of human skin tissue, according to new research appearing in Tuesdays edition of the journal Nature.

Scientists from Oregon Health & Science University (OHSU), the University of California-San Diego (UCSD) School of Medicine and the Salk Institute for Biological Studies created stem cells using two different methods: nuclear transfer, which involves moving genetic material from a skin cell into an empty egg cell, and a more traditional method in which activating a small number of genes reverts adults cells back to an embryonic state.

Experts believe that stem cell therapies could someday be used to replace human cells damaged through injury or illness, including spinal cord injuries, diabetes, Parkinsons disease and multiple sclerosis. Human embryonic stem cells (ES cells), which are cells cultured from discarded embryos, are viewed by scientists as the gold standard of the field, and the new study reports that somatic cell nuclear transfer (SCNT) more closely resembled ES cells.

This marks the first time that researchers had directly compared the SCNT method with the induced pluripotent stem cell (iPS cell) technique, and in a statement, co-senior author and UCSD assistant professor in reproductive medicine Dr. Louise Laurent explained that the nuclear transfer ES cells were more completely reprogrammed and had fewer alterations in gene expression and DNA methylation levels than the iPS cells.

Access to actual human embryonic stem cells (hESCs) has been limited in the US due to ethical and logistical issues, forcing researchers to devise other methods to create stem cells, the study authors explained. Typically, that means creating iPS cells by taking adult cells and adding in a mixture of genes that regress those cells to a pluripotent stem-cell state. Those cells can then be coaxed into cells resembling those found in the heart or brain.

Over the past year, however, an OHSU-led team of researchers have built upon somatic cell nuclear transfer (the same technique used for cloning organisms) to transplant the DNA-containing nucleus of a skin cell into an empty human egg. Once completed, the combination naturally matures into a group of stem cells.

For the first time, the OHSU, UCSD and Salk Institute researchers conducted a direct, in-depth comparison of the two different methods. They created four nuclear transfer ES cell lines and seven iPS cell lines using the same skin cells as the donor genetic material source, and then compared them to a pair of standard human ES lines.

A battery of standard tests revealed that all 13 cell lines were shown to be pluripotent. However, when the researchers used powerful genomic techniques to take a closer look at the DNA methylation (a biochemical process responsible for turning genes on or off) and the gene expression signatures of each cell line, they discovered that the nuclear transfer ES cells more closely resembled those of ES cells than did iPS cells in both characteristics.

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Stem cell type resists chemotherapy drug

Posted: July 3, 2014 at 9:41 pm

A new study shows that adipose-derived human stem cells, which can become vital tissues such as bone, may be highly resistant to the common chemotherapy drug methotrexate (MTX). The preliminary finding from lab testing may prove significant because MTX causes bone tissue damage in many patients.

MTX is used to treat cancers including acute lymphoblastic leukemia, the most common form of childhood cancer. A major side effect of the therapy, however, is a loss of bone mineral density. Other bone building stem cells, such as bone marrow derived stem cells, have not withstood MTX doses well.

"Kids undergo chemotherapy at such an important time when they should be growing, but instead they are introduced to this very harsh environment where bone cells are damaged with these drugs," said Olivia Beane, a Brown University graduate student in the Center for Biomedical Engineering and lead author of the study. "That leads to major long-term side effects including osteoporosis and bone defects. If we found a stem cell that was resistant to the chemotherapeutic agent and could promote bone growth by becoming bone itself, then maybe they wouldn't have these issues."

Stem cell survivors

Originally Beane was doing much more basic research. She was looking for chemicals that could help purify adipose-derived stem cells (ASCs) from mixed cell cultures to encourage their proliferation. Among other things, she she tried chemotherapy drugs, figuring that maybe the ASCs would withstand a drug that other cells could not. The idea that this could help cancer patients did not come until later.

In the study published online in the journal Experimental Cell Research, Beane exposed pure human ASC cultures, "stromal vascular fraction" (SVF) tissue samples (which include several cell types including ASCs), and cultures of human fibroblast cells, to medically relevant concentrations of chemotherapy drugs for 24 hours. Then she measured how those cell populations fared over the next 10 days. She also measured the ability of MTX-exposed ASCs, both alone and in SVF, to proliferate and turn into other tissues.

Beane worked with co-authors fellow center member Eric Darling, the Manning Assistant Professor in the Department of Molecular Pharmacology, Physiology and Biotechnology, and research assistant Vera Fonseca.

They observed that three chemotherapy drugs -- cytarabine, etoposide, and vincristine -- decimated all three groups of cells, but in contrast to the fibroblast controls, the ASCs withstood a variety of doses of MTX exceptionally well (they resisted vincristine somewhat, too). MTX had little or no effect on ASC viability, cell division, senescence, or their ability to become bone, fat, or cartilage tissue when induced to do so.

The SVF tissue samples also withstood MTX doses well. That turns out to be significant, Darling said, because that's the kind of tissue that would actually be clinically useful if an ASC-based therapy were ever developed for cancer patients. Hypothetically, fresh SVF could be harvested from the fat of a donor, as it was for the study, and injected into bone tissue, delivering ASCs to the site.

To understand why the ASCs resist MTX, the researchers conducted further tests. MTX shuts down DNA biosynthesis by binding the protein dihydrofolate reductase so that it is unavailable to assist in that essential task. The testing showed that ASCs ramped up dihydrofolate reductase levels upon exposure to the drug, meaning they produced enough to overcome a clinically relevant dose of MTX.

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Stem cell type resists chemotherapy drug

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Some stem cell methods closer to 'gold standard' than others

Posted: July 3, 2014 at 9:41 pm

PUBLIC RELEASE DATE:

2-Jul-2014

Contact: Kristina Grifantini press@salk.edu Salk Institute

LA JOLLA-Researchers around the world have turned to stem cells, which have the potential to develop into any cell type in the body, for potential regenerative and disease therapeutics.

Now, for the first time, researchers at the Salk Institute, with collaborators from Oregon Health & Science University and the University of California, San Diego, have shown that stem cells created using two different methods are far from identical. The finding could lead to improved avenues for developing stem cell therapies as well as a better understanding of the basic biology of stem cells.

The researchers discovered that stem cells created by moving genetic material from a skin cell into an empty egg cell-rather than coaxing adult cells back to their embryonic state by artificially turning on a small number of genes-more closely resemble human embryonic stem cells, which are considered the gold standard in the field.

"These cells created using eggs' cytoplasm have fewer reprogramming issues, fewer alterations in gene expression levels and are closer to real embryonic stem cells," says co-senior author Joseph R. Ecker, professor and director of Salk's Genomic Analysis Laboratory and co-director of the Center of Excellence for Stem Cell Genomics. The results of the study were published today in Nature.

Human embryonic stem cells (hESCs) are directly pulled from unused embryos discarded from in-vitro fertilization, but ethical and logistical quandaries have restricted their access. In the United States, federal funds have limited the use of hESCs so researchers have turned to other methods to create stem cells. Most commonly, scientists create induced pluripotent stem (iPS) cells by starting with adult cells (often from the skin) and adding a mixture of genes that, when expressed, regress the cells to a pluripotent stem-cell state. Researchers can then coax the new stem cells to develop into cells that resemble those in the brain or in the heart, giving scientists a valuable model for studying human disease in the lab.

Over the past year, a team at OHSU built upon a technique called somatic cell nuclear transfer (the same that is used for cloning an organism, such as Dolly the sheep) to transplant the DNA-containing nucleus of a skin cell into an empty human egg, which then naturally matures into a group of stem cells.

Ecker, holder of the Salk International Council Chair in Genetics, teamed up with Shoukhrat Mitalipov, developer of the new technique and director of the Center for Embryonic Cell and Gene Therapy at OHSU, and UCSD assistant professor Louise Laurent to carry out the first direct comparison of the two approaches. The scientists created four lines of nuclear transfer stem cells all using eggs from a single donor, along with seven lines of iPS cells and two lines of the gold standard hESCs. All cell lines were shown to be able to develop into multiple cell types and had nearly identical DNA content contained within them.

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