Category Archives: Stem Cells

Its been 17 years since Dolly the sheep was cloned from a mammary cell. And now scientists applied the same technique to make the first embryonic-stem-cell lines from human skin cells.

Ever since Ian Wilmut, an unassuming embryologist working at the Roslin Institute just outside Edinburgh stunned the world by cloning the first mammal, Dolly, scientists have been asking: Could humans be cloned in the same way? Putting aside the ethical challenges the question raised, the query turned out to involve more wishful thinking than scientific success. Despite the fact that dozens of other species have been cloned using the technique, called nuclear transfer, human cells have remained stubbornly resistant to the process.

Until now. Shoukhrat Mitalipov, a professor at Oregon Health & Science University, and his colleagues report in the journal Cell that they have successfully reprogrammed human skin cells back to their embryonic state. The purpose of the study, however, was not to generate human clones but to produce lines of embryonic stem cells. These can develop into muscle, nerve, or other cells that make up the bodys tissues. The process, he says, took only a few months, a surprisingly short period to reach such an important milestone.

(MORE:Stem-Cell Research: The Quest Resumes)

Nuclear transfer involves inserting a fully developed cell in Mitalipovs study, the cells came from the skin of fetuses into the nucleus of an egg, and then manipulating the egg to start dividing, a process that normally only occurs after it has been fertilized by a sperm. After several days, the ball of cells that results contains a blanket of embryonic stem cells endowed with the genetic material of the donor skin cell, which have the ability to generate every cell type from that donor. In Dollys case, those cells were allowed to continue developing into an embryo that was then transferred to a ewe to produce a cloned sheep. But Mitalipov says his process with the human cells isnt designed to generate a human clone, but rather just to create the embryonic stem cells. These could then be manipulated to create heart, nerve or other cells that can repair or treat disease.

I think this is a really important advance, says Dieter Egli, an investigator at the New York Stem Cell Foundation. I have a very high confidence that versions of this technique will work very well; its something that the field has been waiting for. Egli is among the handful of scientists who have been working to perfect the technique with human cells and, in 2011, succeeded in producing human stem cells, but with double the number of chromosomes. In 2004, Hwang Woo-suk, a veterinary scientist at Seoul National University, claimed to have succeeded in achieving the feat, but later admitted to faking the data. Instead of generating embryonic-stem-cell lines via nuclear transfer, Hwangs group produced the stem cells from days-old embryos, a technique that had already been established by James Thomson at University of Wisconsin in 1998.

That scandal, as well as ethical concerns about the dangers of encouraging work that could lead to human cloning, dried up interest in getting the process to work with human cells. Then came a breakthrough in 2007, when Shinya Yamanaka of Kyoto University succeeded in reprogramming adult skin cells back to their embryonic state simply by dousing them in a concoction of four genetic factors and some growth media. That technique for generating embryonic-like stem cells (called induced pluripotent stem cells, or iPS cells) bypassed the need for transferring the cells into eggs, as Wilmut had done, and also averted the ethical issues attached to extracting stem cells from embryos as Thomson had done. Plus, the iPS cells had the advantage that patients could generate their own stem cells and potentially grow new cells they might need to treat or avert diseases like diabetes, Alzheimers or heart problems.

Except that researchers still couldnt prove that the heart, nerve, muscle and other cells they made from the iPS cells were exactly like the ones generated from the embryonic stem cells. The gold standard embryonic stem cells still came from embryos themselves, including ones that were made through nuclear transfer.

(MORE: Stem-Cell Miracle? New Therapies May Cure Chronic Conditions Like Alzheimers)

Now that the technique appears to work with human cells, the process could be another source of generating stem cells that may ultimately treat patients, says Mitalipov. His group is especially interested in promoting the technique for treating mitochondrial diseases these organelles posses a different set of DNA than that contained in the nucleus of cells, and are responsible for generating the energy needed for cells to function. But because they lie outside the nucleus, transferring cells from a patient with mitochondrial diseases into a donor egg that has a healthy set of mitochondrial DNA would generate populations of cells that are free of disease.

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Scientists Report First Success in Cloning Human Stem Cells

US researchers have reported a breakthrough in stem cell research, describing how they have turned human skin cells into embyronic stem cells for the first time.

The method described Wednesday by Oregon State University scientists in the journal Cell, would not likely be able to create human clones, said Shoukhrat Mitalipov, senior scientist at the Oregon National Primate Research Center.

But it is an important step in research because it does not require the use of embryos in creating the type of stem cell capable of transforming into any other type of cell in the body.

The technique involves transplanting an individual's DNA into an egg cell that has been stripped of genetic material, a variation of a method called somatic cell nuclear transfer.

"A thorough examination of the stem cells derived through this technique demonstrated their ability to convert just like normal embryonic stem cells, into several different cell types, including nerve cells, liver cells and heart cells," said Mitalipov.

He added that since the reprogrammed cells use genetic material from the patient, there is no concern about transplant rejection.

"While there is much work to be done in developing safe and effective stem cell treatments, we believe this is a significant step forward in developing the cells that could be used in regenerative medicine," Mitalipov said.

Another advantage of this approach is that it does not use fertilized embryos to obtain stem cells, a technique that raises major ethical issues because the embryo is destroyed.

Since the birth of the sheep Dolly in 1996 in the United Kingdom, the first cloned animal, researchers have cloned some 20 species including goats and rabbits, but never monkeys or primates whose biologies and reproduction is more complex.

Years of research on monkey cells using the same technique have not successfully produced any monkey clones.

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US researchers make embryonic stem cells from skin

US researchers have reported a breakthrough in stem cell research, describing how they have turned human skin cells into embryonic stem cells for the first time.

The method described Wednesday by Oregon Health and Science University scientists in the journal Cell, would not likely be able to create human clones, said Shoukhrat Mitalipov, senior scientist at the Oregon National Primate Research Center.

But it is an important step in research because it does not require the use of embryos in creating the type of stem cell capable of transforming into any other type of cell in the body.

The technique involves transplanting an individual's DNA into an egg cell that has been stripped of genetic material, a variation of a method called somatic cell nuclear transfer.

"A thorough examination of the stem cells derived through this technique demonstrated their ability to convert just like normal embryonic stem cells, into several different cell types, including nerve cells, liver cells and heart cells," said Mitalipov.

He added that since the reprogrammed cells use genetic material from the patient, there is no concern about transplant rejection.

"While there is much work to be done in developing safe and effective stem cell treatments, we believe this is a significant step forward in developing the cells that could be used in regenerative medicine," Mitalipov said.

Another advantage of this approach is that it does not use fertilized embryos to obtain stem cells, a technique that raises major ethical issues because the embryo is destroyed.

Since the birth of the sheep Dolly in 1996 in the United Kingdom, the first cloned animal, researchers have cloned some 20 species including goats and rabbits, but never monkeys or primates whose biologies and reproduction is more complex.

Years of research on monkey cells using the same technique have not successfully produced any monkey clones.

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Researchers make embryonic stem cells from skin

WEDNESDAY, May 15 (HealthDay News) -- Scientists report they've used a cloning technique to reprogram an ordinary human skin cell to become an embryonic stem cell. In turn, the new stem cell has the potential to transform into any type of cell in the body.

Besides marking a breakthrough in stem cell technology, which has the potential to one day cure a myriad of illnesses, the achievement has some concerned that scientists are moving a step closer to human cloning.

That's because the new stem cell is genetically identical to cells from the person from whom it was derived. Stem cells can differentiate into cells for all of the tissue types that the body needs, such as nerves, muscle and bone.

While Dolly the Sheep was cloned in 1996, and other species have been cloned since, researchers have been unable to clone a primate such as a monkey, chimpanzee or human. However, the technological advances described in the new study are such that "it's a matter of time before they produce a cloned monkey," Jose Cibelli, a cloning expert at Michigan State University who wasn't involved in the study, told the Wall Street Journal.

The new research was published online May 15 in the journal Cell, and was led by Shoukhrat Mitalipov, a senior scientist at the Oregon National Primate Research Center, in partnership with researchers at Oregon Health & Science University (OHSU).

The research involved a version of what's known as somatic cell nuclear transfer, where the cell's nucleus -- which contains all a person's genetic information -- is transferred into an egg cell that has had all of its DNA removed. Once the new nucleus is in place, the unfertilized egg cell proceeds to develop and produce stem cells, according to an OHSU news release.

"Stem cells derived through this technique demonstrated their ability to convert just like normal embryonic stem cells, into several different cell types, including nerve cells, liver cells and heart cells," Mitalipov said in the news release. "While there is much work to be done in developing safe and effective stem cell treatments, we believe this is a significant step forward in developing the cells that could be used in regenerative medicine."

Regenerative medicine is the term used to describe therapies where stem cells are used to regenerate tissues lost to illness or injury.

One key point in the new research: Creation of the new, functioning embryonic stem cell did not involve the use of fertilized embryos, the focus of heated debate over the past decade.

Mitalipov's team says the road to success was not easy, because human egg cells seem to be more fragile than those from other species. That meant that methods had to be tested in monkeys first, in a trial-and-error fashion, before moving to human eggs.

Excerpt from:
Scientists Use Cloning Technique to Produce Human Stem Cells

For all its promise, embryonic stem cell research has been slow going in the last few decades. Ethical quandaries and scientific difficulty have conspired to keep the next big advance just out of reach, but a new study published this week in the journal Cell could kick off a new age of interest in stem cell therapies. Researchers from Oregon Health & Science University have managed to clone human embryonic stem cells using unfertilized eggs and human skin cells.

The process is very similar to the method used over a decade ago to clone Dolly the sheep, but the aim here was not to produce a human clone. Rather, scientists wanted to make a line of stem cells that would not be rejected by a recipients own immune system, In fact, according to Professor Shoukhrat Mitalipov from Oregon Health & Science University, it is unlikely the embryos used in the study had any hope of developing into viable human clones.

To create these new stem cell lines, researchers removed the DNA from donated unfertilized human eggs. A skin cell from a different individual was then inserted into the egg cell. The trick that made this advance possible is in finding a way to entice that cell to begin dividing. Mitalipov and his team eventually found that exposure to precisely-timed electric pulses and a chemical bath with a bit of caffeine did the trick.

The result is a small bundle of embryonic stem cells that match the genotype of the skin cell donor, not the egg donor. Stem cells created in this process are known as pluripotent, because they can differentiate to become a wide variety of cell types. They could conceivably be turned into cardiac muscle, nerve cells, pancreatic cells, or any number of other tissues to treat disease.

Additionally, the maturation process is well established for the cells in this study. They actually appear to become functional adult cells when harvested. Researchers even managed to create cardiac cells that contract just like the real thing. Previous stem cell discoveries using only regressed skin cells come with many unanswered questions, thus the continued use of human embryos.

Having a way to manufacture stem cells that match a persons DNA is revolutionary in stem cell therapy. If you implant cells that dont match someones genotype, they are likely to be rejected. This is why transplant patients must take immunosuppressive drugs. This process could lead to treatments where doctors create new tissues to treat patients that are essentially their own cells.

Other researchers are anxious to attempt the process themselves, and hopefully confirm Mitalipovs results. The entire paper is online if you want to check it out.

Now read:Scientists end our dreams of cloning dinosaurs

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Scientists clone human stem cells for the first time

Stem cells breakthrough in cloned human embryos

(WAM) / 17 May 2013

Scientists have finally recovered stem cells from cloned human embryos, a longstanding goal that could lead to new treatments for such illnesses as Parkinsons disease and diabetes.

A prominent expert called the work a landmark, but noted that a different, simpler technique now under development may prove more useful.

Stem cells can turn into any cell of the body, so scientists are interested in using them to create tissue for treating disease. Transplanting brain tissue might treat Parkinsons disorder, for example, and pancreatic tissue might be used for diabetes.

But transplants run the risk of rejection, so more than a decade ago, researchers proposed a way around that: Create tissue from stem cells that bear the patients own DNA, obtained with a process called therapeutic cloning.

If DNA from a patient is put into a human egg, which is then grown into an early embryo, the stem cells from that embryo would provide a virtual genetic match. So in theory, tissues created from them would not be rejected by the patient.

That idea was met with some ethical objections because harvesting the stem cells involved destroying human embryos.

Scientists have tried to get stem cells from cloned human embryos for about a decade, but theyve failed. Generally, thats because the embryos stopped developing before producing the cells. In 2004, a South Korean scientist claimed to have got stem cells from cloned human embryos, but that turned out to be a fraud.

In Wednesdays edition of the journal Cell, however, scientists in Oregon report harvesting stem cells from six embryos created from donated eggs. Two embryos had been given DNA from skin cells of a child with a genetic disorder, and the others had DNA from fetal skin cells.

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Stem cells’ breakthrough in cloned human embryos

Oregon Health&Science University

Donor egg held by pipette prior to nuclear extraction.

By Maggie Fox, Senior Writer, NBC News

Researchers say they have finally managed to use cloning technology to make human embryos and grow stem cells from them in the hopes of making perfectly matched grow-your-own tissue transplants.

They used a human egg cell and parts of a human skin cell to grow a very early human embryo, then transformed cells from this ball of cells into beating heart cells and skin cells. The process may eventually help treat a range of diseases, from Parkinsons to rare inherited conditions, they reported Wednesday in the journal Cell.

The researchers, at Oregon Health & Science University, say their embryos almost certainly could not grow into living human babies or even start a pregnancy theyre deficient in a key way. But they admit also that they havent quite overcome ethical qualms about working with human embryos.

However, the work opens another route to treatments using human embryonic stem cells, the bodys master cells. These stem cells are kind of very early unprogrammed cells but they have the capacity to become any other cell type, says Shoukhrat Mitalipov, who led the research.

These cells are very different from so-called adult stem cells, like those taken from bone marrow. Adult stem cells cannot give rise to cells of other tissue types -- blood cells cannot be used to make brain cells, for instance.

Dr. George Daley, a stem cell expert at Harvard Medical School, called it a "beautiful piece of work".

When human embryonic stem cells were first discovered in 1998, scientists immediately dreamed of using cloning technology to help people grow their own organ and tissue transplants, and to use them to study disease. Theyd be perfect genetic matches for each patient, meaning an end to a lifetime of taking dangerous immune-suppressing drugs after an organ transplant.

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Via cloning, human stem cells

Stem cells viewed on a computer screen at the University of Connecticut's Stem Cell Institute.

STORY HIGHLIGHTS

(TIME.com) -- It's been 17 years since Dolly the sheep was cloned from a mammary cell. And now scientists applied the same technique to make the first embryonic stem cell lines from human skin cells.

Ever since Ian Wilmut, an unassuming embryologist working at the Roslin Institute just outside of Edinburgh stunned the world by cloning the first mammal, Dolly, scientists have been asking -- could humans be cloned in the same way?

Putting aside the ethical challenges the question raised, the query turned out to involve more wishful thinking than scientific success. Despite the fact that dozens of other species have been cloned using the technique, called nuclear transfer, human cells have remained stubbornly resistant to the process.

Until now. Shoukhrat Mitalipov, a professor at Oregon Health & Science University, and his colleagues report in the journal Cell that they have successfully reprogrammed human skin cells back to their embryonic state.

The purpose of the study, however, was not to generate human clones but to produce lines of embryonic stem cells. These can develop into muscle, nerve, or other cells that make up the body's tissues. The process, he says, took only a few months, a surprisingly short period to reach such an important milestone.

TIME.com: Stem cell scientists awarded Nobel Prize in Physiology and Medicine

Nuclear transfer involves inserting a fully developed cell -- in Mitalipov's study, the cells came from the skin of fetuses -- into the nucleus of an egg, and then manipulating the egg to start dividing, a process that normally only occurs after it has been fertilized by a sperm.

After several days, the ball of cells that results contains a blanket of embryonic stem cells endowed with the genetic material of the donor skin cell, which have the ability to generate every cell type from that donor.

Read the rest here:
Success! Human stem cells cloned