Stem Cell Basics I. | stemcells.nih.gov

Stem cells have the remarkable potential to develop into many different cell types in the body during early life and growth. In addition, in many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.

Stem cells are distinguished from other cell types by two important characteristics. First, they are unspecialized cells capable of renewing themselves through cell division, sometimes after long periods of inactivity. Second, under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions.

Until recently, scientists primarily worked with two kinds of stem cells from animals and humans: embryonic stem cells and non-embryonic "somatic" or "adult" stem cells. The functions and characteristics of these cells will be explained in this document. Scientists discovered ways to derive embryonic stem cells from early mouse embryos more than 30 years ago, in 1981. The detailed study of the biology of mouse stem cells led to the discovery, in 1998, of a method to derive stem cells from human embryos and grow the cells in the laboratory. These cells are called human embryonic stem cells. The embryos used in these studies were created for reproductive purposes through in vitro fertilization procedures. When they were no longer needed for that purpose, they were donated for research with the informed consent of the donor. In 2006, researchers made another breakthrough by identifying conditions that would allow some specialized adult cells to be "reprogrammed" genetically to assume a stem cell-like state. This new type of stem cell, called induced pluripotent stem cells (iPSCs), will be discussed in a later section of this document.

Stem cells are important for living organisms for many reasons. In the 3- to 5-day-old embryo, called a blastocyst, the inner cells give rise to the entire body of the organism, including all of the many specialized cell types and organs such as the heart, lungs, skin, sperm, eggs and other tissues. In some adult tissues, such as bone marrow, muscle, and brain, discrete populations of adult stem cells generate replacements for cells that are lost through normal wear and tear, injury, or disease.

Given their unique regenerative abilities, stem cells offer new potentials for treating diseases such as diabetes, and heart disease. However, much work remains to be done in the laboratory and the clinic to understand how to use these cells for cell-based therapies to treat disease, which is also referred to as regenerative or reparative medicine.

Laboratory studies of stem cells enable scientists to learn about the cells essential properties and what makes them different from specialized cell types. Scientists are already using stem cells in the laboratory to screen new drugs and to develop model systems to study normal growth and identify the causes of birth defects.

Research on stem cells continues to advance knowledge about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. Stem cell research is one of the most fascinating areas of contemporary biology, but, as with many expanding fields of scientific inquiry, research on stem cells raises scientific questions as rapidly as it generates new discoveries.

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Stem Cell Basics I. | stemcells.nih.gov

What are human embryonic stem cells used for? | Europe’s stem …

Human embryonic stem cells (hESCs) can be used in research to:

Researchers can use hESCs to produce specialized cells like nerve or heart cells in the lab. These specialized cells can be studied in detail to understand more about the causes and development of diseases. They can also be used to reveal how our cells react to, or could be treated with potential new drugs. This is particularly useful for studying types of cells that cannot easily be obtained by taking tissue from patients, e.g. brain cells.

Recently, hESCs have been produced that meet the strict quality requirements for use in medical treatments. These clinical grade hESCs have been approved for use in a small number of early clinical trials. One example is a trial led by The London Project to Cure Blindness, using hESCs to produce a particular type of eye cell for treatment of patients with the eye disease age-related macular degeneration. The biotechnology company ACT is also using human ESCs to make cells for patients with an eye disease: Stargardts macular dystrophy.

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Are embryonic stem cells and artificial stem cells equivalent?

October 29, 2015 by Hannah L. Robbins HSCI researchers made artificial stem cells, or induced pluripotent stem cells (iPSCs), from embryonic stem cells, then turned them into the neural cells pictured here. Credit: Jiho Choi

Harvard Stem Cell Institute (HSCI) researchers at Massachusetts General Hospital and Harvard Medical School have found new evidence suggesting some human induced pluripotent stem cells are the 'functional equivalent' of human embryonic stem cells, a finding that may begin to settle a long running argument.

The findings were published this week in Nature Biotechnology.

From 1998 until 2007 embryonic stem cells (ES cells) were the only human cells known with the potential to become any other type of cell in the body. When Shinya Yamanaka discovered how to engineer adult somatic cells to a state where they, too, had this potentiala discovery for which he was awarded the Nobel Prizescientists could then reprogram nearly any type of adult cell, including the oft-used skin and blood cells, to make induced pluripotent stem cells, or iPS cells.

The discovery, however, ignited a debate that is still ongoing over whether iPS cells are as good as ES cells. Hundreds of research experiments have been conducted, some suggesting the two types are functionally similar and can be used interchangeably and others suggesting they are fundamentally different.

Konrad Hochedlinger, PhD, HSCI Principal Faculty member, a senior author on the paper, and a leader in studying iPS cell reprogramming, said his lab has been working to "understand if these artificially generated stem cells, the induced pluripotent stem cells, are equivalent to embryonic stem cells."

Experiments designed to compare iPS cells to ES cells are difficult to carry out, said Hochedlinger. Researchers want to know if the reprogramming process that converts an adult cell into an iPS cell somehow changes the cell's ability to properly regulate its genesmaking the artificial stem cell behave differently, but it is difficult to tell by comparing these two cell types to eachother.

Because the cells come from two different sources, they are inherently genetically different. A side-by-side comparison would show variation, but it would remain unclear whether the variation was due to the difference between sex, race, and/or ancestry in the two cells, or from the reprogramming process.

In order to compare cell types, Hochedlinger and his colleagues needed to start with cells that were genetically identical. Then if they were to see variation, it would likely be from the reprogramming process and not the cells' genetic backgrounds.

Jiho Choi, a PhD student in the Hochedlinger lab and first author on the paper, "tricked" human ES cells into becoming human iPS cells by first coaxing two well-studied lines of ES cells to form skin cells. He then reprogrammed those skin cells into iPS cells before sequencing the gene products of the two cell types to see if they were identical.

After sequencing, the researchers teamed up with Soohyun Lee, a research fellow at HMS, and Peter Park, PhD, HSCI Affiliated Faculty member and co-senior author on the study. Park's group found only about 50 of the 200,000 genes that make up the human genome were expressed differently between the two cell types.

In fact, these differentially expressed genes were transcribed at such low levels, Park believes the difference may be 'transcriptional noise.' If you look at the whole landscape of the genome those genes may be a little bumps rather than large mountains, Hochedlinger explained. "They might be scored as different, but there may not be any biological repercussions. "

Additionally, when the researchers assessed the functional properties of their ES and iPS cell lines, they found that they had equal potentials to differentiate into neural cells and a variety of other specialized cell lineages.

"When using these cell lines and assays, and after considering a number of technical and biological variables, we find that ES cells and iPS cells are equivalent," said Hochedlinger, adding the caveat that not all practical applications can account for the variables, and that the science has not yet advanced to where iPS cells can replace embryonic stem cells in every situation.

"Embryonic stem cells are still an important reference point, against which other pluripotent cells are compared," said Hochedlinger. "Along those lines, this study increases the 'value' of iPS cells."

Explore further: What's good for the mouse is good for the monkey: Skin cells reprogrammed into stem cells

More information: Jiho Choi et al. A comparison of genetically matched cell lines reveals the equivalence of human iPSCs and ESCs, Nature Biotechnology (2015). DOI: 10.1038/nbt.3388

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Are embryonic stem cells and artificial stem cells equivalent?

Embryonic Stem Cell Maintenance & Differentiation (Human)

Reduce variation with the most complete, defined system for human embryonic stem cell (ES cell) and induced pluripotent stem cell (iPS cell) culture featuring mTeSR1 and the TeSR media family. From generation of iPS cells to maintenance, differentiation, characterization and cryopreservation of ES and iPS cells, see how you can "Maximize Your Pluripotential".

A Complete System for Supporting Your Human Pluripotent Stem Cell Research Human pluripotent stem cell (hPSC) research is an expanding field that has potential to change the way human diseases are studied and treated. The ability to differentiate ES cells and iPS cells to specific downstream cell types opens up new avenues for drug development and regenerative medicine.

STEMCELL Technologies offers an array of products designed to support the various steps of your ES and iPS cell culture workflow, from isolation, reprogramming and expansion to directed differentiation and characterization. For help with your hPSC workflow decision making, use ourinfographicsto find the right reagents for you.

Small Molecules for Reprogramming iPS cells have been traditionally generated through exogenous expression of pluripotency genes (via viral or episomal vectors). However, small molecules are increasingly being utilized and have been demonstrated to increase reprogramming efficiency:

Small Molecules for Maintenance Maintenance of stem cells in defined culture systems can reduce experimental variability. Small molecules have been used to stimulate the self-renewal capabilities of ES and iPS cells or increase viability of single cells.

TeSR-E5 and TeSR-E6 are defined, serum- and xeno-free media that are based on the formulation of TeSR-E8, but do not contain transforming growth factor (TGF-), basic fibroblast growth factor (bFGF), or in the case of TeSR-E5, insulin. They may be used as basal media for differentiation of human ES or iPS cells or other applications where removal of the above cytokines and insulin is desirable. To learn more about the functions of the different cytokines in the TeSR media, click here.

Small Molecules for Differentiation Differentiation of pluripotent stem cells to specialized cell types requires selective activation or inhibition of specific signaling pathways. Small molecules have been used to identify pathways required for differentiation, and are often used in place of expensive growth factors to direct differentiation.

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Embryonic Stem Cell Maintenance & Differentiation (Human)

Myths and Misconceptions About Stem Cell Research …

En Espaol

There is no shortage of myths and misconceptions when it comes to stem cell research and regenerative medicine. Here we address the most common concerns.

If you have more questions that aren't addressed here, please visit our other Stem Cell FAQ pages.

Is CIRM-funded stem cell research carried out ethically? Where do the embryos come from to create stem cell lines? I'm opposed to abortion. Can embryonic stem cell lines come from aborted fetuses? Does creating stem cell lines destroy the embryo? Are adult stem cells as goodor betterthan embryonic stem cells? Don't iPS cells eliminate the need to use embryos in stem cell research? Can't stem cell research lead to human cloning?

Stem cell research, like field within biomedicne, poses social and ethical concerns. CIRM, as well as the broader research community, takes these seriously.

As a state funding body, CIRM has comprehensive policies to govern research, similar to our national counterpart, the National Institutes of Health. CIRM-funded researchers must comply with a comprehensive set of regulations that have been carefully developed and are in accordance with national and international standards.

These regulations were among the first formal policies governing the conduct of stem cell research and are in accordance with recommendations from the National Academies and from the International Society for Stem Cell Research. CIRMs Standards Working Group meets regularly to consider new ethical challenges as the science progresses and to revise standards to reflect the current state of the research.

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CIRM regulations National Academies of Science guidelines International Society for Stem Cell Research guidelines National Academies of Science podcast about guidelines for embryonic stem cell research More about CIRM-grantee ethics training (4:03)

All the human embryonic stem cell lines currently in use come from four to five day-old embryos left over from in vitro fertilization (IVF) procedures. In IVF, researchers mix a man's sperm and a woman's eggs together in a lab dish. Some of those eggs will become fertilized. At about five days the egg has divided to become a hollow ball of roughly 100 cells called a blastocyst which is smaller than the size of the dot over an i. It is these very early embryos that are implanted into the woman in the hopes that she becomes pregnant.

Each cycle of IVF can produce many blastocysts, some of which are implanted into the woman. The rest are stored in the IVF clinic freezer. After a successful implantation, they must decide what to do with any remaining embryos. There are a few options:

Some embryonic stem cell lines also come from embryos that a couple has chosen not to implant because they carry harmful genetic mutations like the ones that cause cystic fibrosis or Tay Sachs disease. These are discovered through routine genetic testing prior to implantation. Still other embryos might be malformed in some way that causes them to be rejected for implantation into the mother. Embryos with genetic defects of malformations would have been discarded if the couple had not chosen to donate them to stem cell research.

People who donate leftover embryos for research go through an extensive consent process to ensure that they understand embryonic stem cell research. Under state, national and international regulations, no human embryonic stem cell lines can be created without explicit consent from the donor.

Policies vary as to whether women may be paid or otherwise compensated to donate eggs. Most jurisdictions allow donors to be reimbursed for direct costs such as travel to the clinic or lodging. Some also allow payments or IVF services to be provided to egg donors.

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How do scientists create stem cell lines from left over IVF embryos? (4:11)

No. Emybronic stem cells only come from four to five day old blastocysts or younger embryos.

In most cases, yes. The hollow blastocystwhich is where embryonic stem cells come fromcontains a cluster of 20-30 cells called the inner cell mass. These are the cells that become embryonic stem cells in a lab dish. The process of extracting these cells destroys the embryo.

Dont forget that the embryos were donated from IVF clinics. They had either been rejected for implantation and were going to be destroyed, or the couple had decided to stop storing the embryos for future use. The embryos used to create embryonic stem cell lines were already destined to be destroyed.

There is, however, a second method that creates embryonic stem cell lines without destroying the embryo. Instead, scientists take a single cell from a very early stage IVF embryo and can use that one cell to develop a new line. The process of removing one cell from an early stage embryo has been done for many years as a way of testing the embryo for genetic predisposition to diseases such as Tay Sachs. This process is called preimplantation genetic testing.

Adult stem cells are extremely valuable and have great potential for future therapies. However, these cells are very restricted in what they can do. Unlike embryonic stem cells, which can grow into virtually any cell type in the body, adult stem cells can only follow certain paths.

For example, Blood-forming stem cells can grow into mature blood cells, and brain stem cells may be able to grow into mature neurons, but a blood-forming stem cell cant grow into a neuron, and vice versa. Whats more, adult stem cells dont grow indefinitely in the lab, unlike embryonic stem cells, and they arent as flexible in the types of diseases they can treat.

And, while the news is full of stories about people who had great results from adult stem cell therapies, few of these therapies are part of big trials that can test whether a potential therapy is safe and effective. Until some of these large trials take place with both adult and embryonic stem cells we won't know which type of stem cell is superior. Even researchers who study adult stem cells advocate working with embryonic cells as well.

CIRM is excited about their potential for treating some diseases. However, our goal is to accelerate new treatments for diseases in need. At this time the most effective way of doing that is by exploring all types of stem cells. That's why CIRM has funded researchers pursuing a wide range of approaches to finding cures for diseases.

See how much of CIRM's funding has gone to different types of stem cells here: Overview of CIRM Stem Cell Research Funding.

Filter our list of all funded CIRM grants to see awards using different cell types.

How are adult stem cell different from embryonic stem cells? (3:29)

Induced pluripotent stem cells, or iPS cells, represent another type of cell that could be used for stem cell research. . iPS cells are adult cellsusually skin cellsthat scientists genetically reprogram to appear like embryonic stem cells. The technology used to generate human iPS cells, pioneered by Shinya Yamanaka in 2007, is very promising, which is why CIRM has funded many grants that create and use these cells to study or treat disease. However, iPS cell technology is very new and it is still not known whether those cells have the same potential as human embryonic stem cells or whether the cells are safe for transplantation.

Many CIRM-funded researchers are working to find better ways of creating iPS cells that are both safe and effective. In the mean time, waiting for iPS cells to become therapeutically safewhich will likely take yearswould slow the search for disease treatments. Cures cant wait, which is why CIRM funds all types of stem cell research.

Experts agree that research on all types of stem cells is critical. In September 2008, a panel of experts convened by the U.S. National Academy of Sciences stated that the use of human embryonic stem cells is still necessary. As panel chair Richard Hynes of the Massachusetts Institute of Technology stated:

It is far from clear at this point which types of cell types will prove to be the most useful for regenerative medicine, and it is likely that each will have some utility.

See a video about creating iPS cells (3:40)

No. Every significant regulatory and advisory body has restrictions on reproductive cloning. The National Academy of Sciences has issued guidelines banning the technique as has the International Society for Stem Cell Research. The California constitution and CIRM regulations specifically prohibit reproductive cloning with its funding.

Updated 1/15

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Myths and Misconceptions About Stem Cell Research ...

Scientific Experts Agree Embryonic Stem Cells Are …

2009

"A UK and Canadian team have manipulated human skin cells to act like embryonic stem cells without using viruses making them safer for use in humans.

"Study leader Dr. Keisuke Kaji, from the Medical Research Council Centre for Regenerative Medicine at the University of Edinburgh, said nobody, including himself, had thought it was really possible. 'It is a step towards the practical use of reprogrammed cells in medicine, perhaps even eliminating the need for human embryos as a source of stem cells,' he said."

--

"'Ethical' stem cell creation hope," BBC News, March 1, 2009, http://news.bbc.co.uk/2/hi/health/7914976.stm

***

"A groundbreaking medical treatment that could dramatically enhance the body's ability to repair itself has been developed by a team of British researchers. The therapy, which makes the body release a flood of stem cells into the bloodstream, is designed to heal serious tissue damage caused by heart attacks and even repair broken bones.

"A possible danger with some other stem cell therapies in the pipeline is their use of embryonic stem cells. Because these can turn into any type of tissue, there is a risk they could grow into cancer cells when injected into patients. [This] treatment uses stem cells that can only grow into blood vessels, bone and cartilage, so the risk of causing cancer is removed."

--

I. Sample, "Revolutionary stem cell therapy boosts body's ability to heal itself," The Guardian (United Kingdom) , January 8, 2009, http://www.guardian.co.uk/science/2009/jan/08/stem-cells-bone-marrow-heart-attack

***

"Controversial research into the use of 'hybrid' human-animal embryos to make stem cells is in danger of stalling because of a lack of funding, British scientists claim.

"Since the furore broke scientists have developed a cheap and powerful new technique in which adult skin cells are reprogrammed to create cells that are almost identical to stem cells. Researchers have already used the technique to make so-called induced pluripotent stem (iPS) cells for patients with diabetes, muscular dystrophy and Down's syndrome.

[Quoting Harry Moore, head of reproductive biology at Sheffield University] 'What has happened is the field has moved on. You could argue that iPS cells are a more important area than hybrids now.' "

--

I. Sample, "Rival stem cell technique takes the heat out of hybrid embryo debate," The Guardian. January 13, 2009, http://www.guardian.co.uk/science/2009/jan/13/hybrid-embryos-stem-cells

***

"A dose of their own stem cells 'reset' the malfunctioning immune system of patients with early-stage multiple sclerosis and, for the first time, reversed their disability.

'This is the first study to actually show reversal of disability,' said Richard Burt, an associate professor in the division of immunotherapy at Northwestern, and the lead author of the study published yesterday in the British journal, the Lancet Neurology. 'Some people had complete disappearance of all symptoms.' "

--

R. Waters, "Dose of Own Stem Cells Reverses Patients' Multiple Sclerosis," Bloomberg News, January 30, 2009, http://www.bloomberg.com/apps/news?pid=20601124&sid=akHXxf3bS3TY&refer=home

***

"A new study suggests that adult bone marrow stem cells can be used in the construction of artificial skin. The findings mark an advancement in wound healing and may be used to pioneer a method of organ reconstruction."

--

"Study Uses Bone Marrow Stem Cells to Regenerate Skin," Physorg, January 14, 2009, http://www.physorg.com/news151166956.html

***

2008

"The reality is that the bulk of today's stem-cell research relies on adult stem cells taken from bone marrow, blood, skeletal muscles, body fat and umbilical cord blood. Scientists have even managed to coax adult skin cells to mimic the versatility of embryonic stem cells, which can grow virtually any cell or tissue in the human body. Unlike embryonic stem cells, though, these adult stem cells are being tested in humans right now, with very real possibilities to change the way various diseases are treated in the next five to 10 years."

--

T. Wheeler, "Stem cells mature," Beacon Journal (Akron, Ohio), April 6, 2008.

***

"For the first time, scientists at Children's Hospital of Pittsburgh of UPMC have discovered a unique population of adult stem cells derived from human muscle that could be used to treat muscle injuries and diseases such as heart attack and muscular dystrophy.

"Because this is an autologous transplant, meaning from the patient to himself, there is not the risk of rejection you would have if you took the stem cells from another source

"Myoendothelial cells also showed no propensity to form tumors, a concern with other stem cell therapies."

--

"Pittsburgh scientists identify human source of stem cells with potential to repair muscle damaged by disease or injury," Children's Hospital of Pittsburgh, September 4, 2007, http://www.pslgroup.com/dg/28732E.htm.

***

2007

"An Ecuadorian stem cellexpert said on September 24 that transplants of autologous adult bone marrow stem cells restored some function in spinal cord injury (SCI) patients who have been paralyzed for an average of four years, some up to 22 years.

"Of the 25 patients who provided more than three months and up to 14 months follow up: 15 gained the ability to stand up, 10 could walk on the parallels with braces, seven could walk without braces and five could walk with crutches. Three patients recovered full bladder control, and 10 patients regained some form of sexual function. No adverse events or abnormal reactions to implantation were observed.

'By implanting an adult's own bone marrow stem cells, we've seen significant improvements in the quality of life for those who suffer from spinal cord injuries,' said Francisco Silva, executive vice president of research and development for PrimeCell Therapeutics."

--

"Marrow Stem Cell Transplants Restore Spinal Cord Functions," Stem Cell Business News, Sept. 24, 2007, http://www.stemcellresearchnews.com/absolutenm/anmviewer.asp?a=867&z=15

***

"In recent years, scientists have discovered that red bone marrow is the body's Swiss Army repair kit. It contains a traveling laboratory of cells that can heal the liver, heart, kidneys, leg arteries, pancreas, and even ovaries and the brain. Up to 40 percent of the liver can be regrown from stem cells found in bone marrow, researchers at New York University School of Medicine, Yale University School of Medicine and Sloan-Kettering Cancer Center found."

--

B. J. Fikes, "Body parts Bone marrow: The body's repair kit," North County Times (San Diego, CA), May 20, 2006, http://www.nctimes.com/lifestyles/health-med-fit/article_0bcace84-44ac-51bc-99a0-b1bf6ddb6d21.html

***

2006

"The results of a study published in the April issue of Stem Cells and Development suggest that human stem cells derived from bone marrow are predisposed to develop into a variety of nerve cell types, supporting the promise of developing stem cell-based therapies to treat neurodegenerative disorders such as Parkinson's disease and multiple sclerosis.

"When transplanted into the central nervous system, [these cells] will develop into a variety of functional neural cell types, making them a potent resource for cell-based therapy."

--

"New Findings Support Promise of Using Stem Cells to Treat Neurodegenerative Diseases," Business Wire, May 1, 2006, http://findarticles.com/p/articles/mi_m0EIN/is_2006_May_1/ai_n16135565/

2005

"A team of Texas and British researchers says it has produced large amounts of embryoniclike stem cells from umbilical cord blood, potentially ending the ethical debate affecting stem-cell research -- the need to kill human embryos. The international researchers said the cells -- called cord-blood-derived-embryoniclike stem cells, or CBEs -- have the ability to turn into any kind of body tissue, like embryonic stem cells do, and can be mass-produced using technology derived from NASA.... "Scientists believe the ability to replicate tissue could lead to the development of ways to replace organs as well as treat life-threatening diseases such as diabetes, Alzheimer's and Parkinson's, which have been the focus of stem-cell research." -- J. Price, "Advance made in stem-cell debate," The Washington Times, August 20, 2005, http://www.washingtontimes.com/national/20050820-122747-2417r.htm

* * *

"Various studies that have been conducted around the world, including a limited number performed in the United States, have suggested that when patients with heart failure receive stem cells taken from their bone marrow, their hearts show signs of improved function and recovery." -- "Stem Cells With Heart Bypass Surgery Trial To Begin At University Of Pittsburgh," ScienceDaily, August 25, 2005, http://www.sciencedaily.com/releases/2005/08/050825070117.htm

* * * "Researchers in Boston have isolated a kind of cell from human bone marrow that they say has all the medical potential of human embryonic stem cells.... "Tufts University researchers used specialized cell-sorting machines to pluck the peculiar cells from samples of bone marrow obtained from different donors. Tests suggested the cells are capable of morphing into many, and perhaps all, of the various kinds of cells that make up the human body. ...

"When a batch of the newly identified marrow cells were injected into the hearts of rats that had experienced heart attacks, some of the cells turned into new heart muscle while others became new blood vessels to support the ailing hearts. ...

"'I think embryonic stem cells are going to fade in the rearview mirror of adult stem cells,' said Douglas W. Losordo, the Tufts cardiologist who left the effort.... Bone marrow, he said, 'is like a repair kit. Nature provided us with these tools to repair organ damage.'"

-Rick Weiss, "Marrow Has Cells Like Stem Cells, Tests Show," Washington Post, Feburary 2, 2005, p. A3, at http://www.washingtonpost.com/wp-dyn/articles/A55369-2005Feb1.html .

* * * "[Erica] Nader, 26, of Farmington Hills, Mich., was the first American to travel to Portugal, in March 2003, for experimental sugery for spinal cord injury. She was injured in July 2001 in an auto accident... She was paralyzed from the top of her arms down. "In the procedure...a team of doctors opened Nader's spinal cord to clear out any scar tissue.... Then, using a long tube, they took a sample of olfactory mucosal cells from the ridge of her nose.... These cells are among the body's richest supply of adult stem cells and are capable of becoming any type of cell, depending on where they are implanted. In this case, these adult stem cells were to take on the job of neurons, or nerve cells, once implanted in the spinal cord at the site of an injury. ... "And after three years, magnetic imaging resonance tests show that the cells indeed promote the development of new blood cells and synapses, or connections between nerve cells, says Dr. Carlos Lima, chief of the Lisbon team. ... "Dr. Pratas Vital, one of two neurosurgeons on the team, calls the transplanted cells spinal cord autografts, a term that indicates the cells come from a person's own body, not fetal or embryonic stem cells. ...

"[Erica] is much stronger and much more capable of lifting her arms, bending her knees on a slanted exercise board and standing erect. ... Once, she was paralyzed from her biceps down. Now, she can push herself off an exercise ball, do arm lifts and help raise herself off a floor mat. ... In the past six weeks, she's started to walk in leg braces with a walker or on a treadmill." -Patricia Anstett, "Paraplegic improving after stem-cell implant," The Indianapolis Star, January 16, 2005, at http://www.indystar.com/articles/5/209449-5235-047.html.

* * * 2004

"[E]vidence from three different labs the University of Minnesota, the Robert Wood Johnson Medical School in New Jersey, and Argonne National Laboratory outside Chicago have found three different ASCs [adult stem cells] that may be completely plastic. ... As the team leader at the Robert Wood Johnson School, Ira Black, told me, 'In aggregate, our study and various others do support the idea that one [adult stem cell] can give rise to all types of tissue.' ...

-Michael Fumento, "The Adult Answer," National Review Online, December 20, 2004, at http://www.nationalreview.com/comment/fumento200412200902.asp.

* * * "Scientists have transplanted adult stem cells from the bone marrow of rats into the brains of rat embryos and found that thousands of the cells survive into adulthood, raising the possibility that someday developmental abnormalities could be prevented or treated in the womb. "Dr. Ira Black, chairman of the department of neuroscience at the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, said the cells took on the properties of brain cells, migrating to specific regions and taking up characteristics of neighboring cells. ... "Black and his colleagues used a specific type of bone marrow cell called a stromal cell, taken from the leg bones of adult rats. 'We see this potentially as an appropriate treatment for prenatal disease, mental retardation and congenital conditions,' Black said. The hope is that a patient's own bone barrow might someday be the source for replacing brain cells lost to illness and brain trauma, experts say, eliminating the need to use human embryonic stem cells. "In a separate study, Dr. Alexander Storch of the University of Ulm, Germany, recently took bone marrow and stromal cells from six healthy people and converted the cells into immature neural stem cells. ... 'A single cell culture could grow all major brain cell types,' said Storch, who used specific growth factors to help them differentiate. ...Storch is now transplanting the cells into mice with multiple sclerosis, Parkinson's disease and stroke symptoms. In the stroke study, the labeled adult stromal cells migrated to the area surrounding the stroke damage, he said. They had all of the chemical, electrical and functional properties of brain cells." -Jamie Talan, "Stem cell transplant a success," Newsday, May 12, 2004, at http://www.mult-sclerosis.org/news/May2004/SuccessfulRatStemCellTransplant.html.

* * * "'Cord blood stem cells have the same capacity to cure disease as do embryonic stem cells, as they can become any cell in the body...,' said Dr. William Schmidt, Jr., an oncologist with the Charleston Cancer Center in N. Charleston, SC. "'The use of umbilical cord blood stem cells in the treatment of disease is one of the most prominent advancements in medicine today. Developments in this field will revolutionize medicine and disease treatment,' said Dr. [Roger] Markwald [Professor and Chair of the Department of Cell Biology and Anatomy at the Medical University of South Carolina]."

-Press Release, "CureSource Issues Statement on Umbilical Cord Blood Stem Cells vs. Embryonic Stem Cells," May 12, 2004, at http://home.businesswire.com/portal/site/altavista/index.jsp?ndmViewId=news_view&newsId=20040512005909&newsLang=en.

* * * "California scientists have found that neural stem cells can target and track deadly brain tumor cells. ...The discovery by researchers at Cedars-Sinai's Maxine Dunitz Neurosurgical Institute in Los Angeles means that neural stem cells may someday be effective 'delivery systems' to transport cancer-killing gene and immune products. ... "'We have previously demonstrated the uncanny ability of neural stem cells to seek out and destroy satellites of tumor cells in the brain,' said John S. Yu, senior author of the study and co-director of the Comprehensive Brain Tumor Program a Cedars-Sinai. '...With this knowledge, we hope to expedite the translation of this powerful and novel strategy for the clinical benefit of patients with brain tumors.'" -Press release, "Neural stem cells may help fight cancer," May 5, 2004, at http://www.nlm.nih.gov/medlineplus/news/fullstory_17570.html. * * * "'We're not trying to change the [adult stem] cells in any way before we put them in the body. These are very early precursor cells. They have the potential to become almost anything, and they adapt quickly once they're inside,' said [Tulane University Center for Gene Therapy research professor Dr. Brian] Butcher. Tests on rats with damaged spines have shown that cell growth occurs in the spine [after adult stem cell injection] and allows the animals to walk again. ... "Using adult stem cells sidesteps some of the legal and ethical issues involved in using fetal...or embryonic stem cells.... And there may be other benefits as well. 'We're not against stem-cell research of any kind,' said Butcher. 'But we think there are advantages to using adult stem cells. For example, with embryonic stem cells, a significant number become cancer cells, so the cure could be worse than the disease. And they can be very difficult to grow, while adult stem cells are very easy to grow.' "But perhaps the biggest advantage to adult stem cells is that they sidestep immunological concerns because the cells used to treat a patient come from his or her own body."

-Heather Heilman, "Great Transformations," The Tulanian, Spring 2004, at http://www2.tulane.edu/article_news_details.cfm?ArticleID=5155.

* * * "Had a major heart attack? In the not-too-distant future, doctors may be able to use stem cells to regenerate damaged heart muscle. And here's the exciting part: They can do it using stem cells that aren't extracted from human embryos. "[G]iven the controversy over harvesting cells from embryos, doctors have been exploring other possibilities. The payoff: A team from the University of Texas M.D. Anderson Cancer Center in Houston recently repaired heart muscles in animals by injecting them with stem cells extracted from human blood. It's the stem-cell equivalent of Columbus reaching America: Not only would cells harvested from one's own body eliminate the risk that they would be rejected, but obtaining them would be a simple, painless proposition. "'This work gives us a way to get the cells that's as easy as giving a blood sample,' says Edward Yeh, M.D., lead author of the study. The real mind boggler is what the stem cells might mean to the 1.2 million Americans who suffer heart attacks each year." -Special Report, "Good news about bad things that happen to your parents," USA Weekend magazine, March 5-7, 2004, p. 6, at http://www.usaweekend.com/04_issues/040307/040307aging.html#heart. * * * 2003

"Scientists in Canada have turned adult skin cells into the building blocks of brain cells --opening the way for their use in new therapies for such incurable diseases. The discovery, by a team at the University of Toronto, is particularly exciting as it promises to provide a readily accessible and ethically neutral source of neural stem cells -- the precursors of nerve and brain tissue. "While other groups have managed to create these cells before, they have generally required the use of adult stem cells from bone marrow, which are difficult and painful to extract, or embryonic stem cells, which require the destruction of a human embryo. "If the Toronto technique is perfected for clinical use it would allow neural stem cells to be made from a patient's skin, ensuring a perfect genetic match that would not be rejected by the body. The cells would then be transplanted into the brains of people with neurological disorders, to replace, for example, the specialized dopamine neurons that are lost in Parkinson's disease." -Oliver Wright, "Patients' Own Skin Cells Turned into Potential Alzheimer's Treatment," The Times (London), December 10, 2003, Home News, p. 8.

* * * "Massachusetts General Hospital researchers have harnessed newly discovered cells from an unexpected source, the spleen, to cure juvenile diabetes in mice, a surprising breakthrough that could soon be tested in local patients and open a new chapter in diabetes research... "'This shows there might be a whole new type of therapy that we haven't tapped into,' said Dr. Denise Faustman, MGH immunology lab director and lead author of the new study, which appears today in the journal Science. 'We've figured out how to regrow an adult organ'." -R. Mishra, "Juvenile diabetes cured in lab mice," The Boston Globe, November 14, 2003, p. A2. * * * "There is now an emerging recognition that the adult mammalian brain, including that of primates and humans, harbours stem cell populations suggesting the existence of a previously unrecognised neural plasticity to the mature CNS [central nervous system], and thereby raising the possibility of promoting endogenous neural reconstruction... Since large numbers of stem cells can be generated efficiently in culture, they may obviate some of the technical and ethical limitations associated with the use of fresh (primary) embryonic neural tissue in current transplantation strategies." -T. Ostenfeld and C. Svendsen, "Recent advances in stem cell neurobiology," Advances and Technical Standards in Neurosurgery, vol. 28 (2003), p. 3. * * * "Stem cells in our bone marrow usually develop into blood cells, replenishing our blood system. However, in states of emergency, the destiny of some of these stem cells may change: They can become virtually any type of cell liver cells, muscle cells, nerve cells responding to the body's needs. Prof. Tsvee Lapidot and Dr. Orit Kollet of the Weizmann Institute's Immunology Department have found how the liver, when damaged, sends a cry for help to these stem cells. 'When the liver becomes damaged, it signals to stem cells in the bone marrow, which rush to it and help in its repair as liver cells,' says Lapidot...

"The findings could lead to new insights into organ repair and transplants, especially liver-related ones. They may also uncover a whole new stock of stem cells that can under certain conditions become liver cells. Until a few years ago only embryonic stem cells were thought to possess such capabilities. Understanding how stem cells in the bone marrow turn into liver cells could one day be a great boon to liver repair as well as an alternative to the use of embryonic stem cells." -"Weizmann Institute scientists find that stem cells in the bone marrow become liver cells," EurakAlert, August 11, 2003, at http://www.eurekalert.org/pub_releases/2003-08/wi-wis_1081103.php.

* * * I.S. Abuljadayel, Chief Scientific Officer of Tri-Stem Inc., on his study published in the July 2003 Current Medical Research and Opinion on producing pluripotent stem cells from adult blood cells:

"This new technology offers a viable option for the generation of large numbers of pluripotent stem cells. These are likely to have many clinical and research applications. The source material is blood, the most accessible tissue in our body which can be extracted by simple venipuncture or aphaeresis. The procedure raises no ethical concerns and removes the need to resort to embryos or aborted fetuses. The technology is also cost-effective, donor-friendly producing relatively large quantities of stem cells within a short time, which could eventually save patient lives and shorten patient waiting lists." -"Stem cell-like plasticity induced in mature mononuclear cells," Reuters Health, July 7, 2003.

* * * "This is an example of promising experimental therapies involving stem cells from bone marrow. Until just a few years ago, conventional wisdom held that only embryonic stem cells could turn into any cell in the body. But that thinking began to change as studies showed that stem cells from bone marrow could become heart, muscle, nerve, or liver cells. Now, the results of clinical trials conducted in Britain, Germany and Brazil show that heart patients injected with their own bone marrow cells benefit from the treatment."

-N. Touchette,"Bone Marrow Stem Cells Heal the Heart," Genome News Network, May 2, 2003, at http://www.genomenewsnetwork.org/articles/05_03/sc_heart.shtml * * * "Stem cells from bone marrow can transform into insulin-producing cells, scientists have shown, suggesting a future cure for diabetes... "Transplants of pancreatic cells have been tried between people, but the supplies are restricted and recipients have to take strong anti-rejection medication. Embryonic stem cells have also been converted into insulin-producing cells, but also produce immune-rejection, in addition to ethical concerns. But taking bone marrow cells from a patient, developing them into beta cells and then reimplanting them would have none of these difficulties. Also, much of the technology for bone marrow transplantation is already well developed, says study leader Mehboob Hussain, at the New York University School of Medicine. "'I am absolutely excited by the potential applications of our findings,' he said. 'In our body, there is an additional, easily available source of cells that are capable of becoming insulin-producing cells.'" -S. Bhattacharya, "Bone marrow experiments suggest diabetes cure," NewScientist.com News Service, March 17, 2003, at http://www.newscientist.com/news/news.jsp?id=ns99993508. * * * 2002

"The use of human embryonic stem cells has been confronted with major obstacles because of bio-ethical and political issues involved obtaining them, as well as the suggestion that embryonic stem cells may lack appropriate developmental instructions, making them potentially less feasible for engrafting into adult tissue... "As compared to embryonic stem cells, adult derived stem cells are endowed with additional developmental instructions and may be better suited for therapeutic purposes. According to [Dr. Shahin Rafii of Cornell University Medical College], 'We are approaching a day when a patient's own stem cells can be induced to divide and develop into tissue that can replace that which is diseased or destroyed, making overcrowded organ transplant lists and rejection of foreign tissues a thing of the past'." -"Mechanism For Regulation Of Adult Stem Cells Found," UniSci - Daily University Science News, May 31, 2002, at http://unisci.com/stories/20022/0531021.htm * * * On the versatility of adult hematopoietic (blood-producing) stem cells, HSCs: "[R]ecent studies have suggested that a subpopulation of HSCs may have the ability to contribute to diverse cell types such as hepatocytes, myocytes, and neuronal cells, especially following induced tissue damage... These surprising findings contradict the dogma that adult stem cells are developmentally restricted." -K. Bunting and R. Hawley, "The tao of hematopoietic stem cells: toward a unified theory of tissue regeneration," Scientific World Journal, April 10, 2002, p. 983.

* * * 2001

Commenting on a study by researchers at New York University, Yale and Johns Hopkins: "'There is a cell in the bone marrow that can serve as the stem cell for most, if not all, of the organs in the body,' says Neil Theise, M.D., Associate Professor of Pathology at NYU School of Medicine... '(t)his study provides the strongest evidence yet that the adult body harbors stem cells that are as flexible as embryonic stem cells'." -"Researchers Discover the Ultimate Adult Stem Cell," ScienceDaily Magazine, May 4, 2001, at http://www.sciencedaily.com/releases/2001/05/010504082859.htm * * * "Umbilical cords discarded after birth may offer a vast new source of repair material for fixing brains damaged by strokes and other ills, free of the ethical concerns surrounding the use of fetal tissue, researchers said Sunday."

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Scientific Experts Agree Embryonic Stem Cells Are ...

An Overview of Stem Cell Research | The Center for …

In November of 1998, scientists reported that they had successfully isolated and cultured human embryonic stem cellsa feat which had eluded researchers for almost two decades. This announcement kicked off an intense and unrelenting debate between those who approve of embryonic stem cell research and those who are opposed to it. Some of the most prominent advocates of the research are scientists and patients who believe that embryonic stem cell research will lead to the development of treatments and cures for some of humanitys most pernicious afflictions (such as Alzheimers disease, Parkinsons disease, heart disease, and diabetes). Among the most vocal opponents of the research are those who share the desire to heal, but who object to the pursuit of healing via unethical means. CBHDs view is that because human embryonic stem cell research necessitates the destruction of human embryos, such research is unethicalregardless of its alleged benefits. Ethical alternatives for achieving those benefits should be actively pursued, and have demonstrated a number of promising preclinical and clincial results without the ethical concers present with embryonic stem cells.

Human embryonic stem cells are the cells from which all 200+ kinds of tissue in the human body originate. Typically, they are derived from human embryosoften those from fertility clinics who are left over from assisted reproduction attempts (e.g., in vitro fertilization). When stem cells are obtained from living human embryos, the harvesting of such cells necessitates destruction of the embryos.

Adult stem cells (also referred to as non-embryonic stem cells) are present in adults, children, infants, placentas, umbilical cords, and cadavers. Obtaining stem cells from these sources does not result in certain harm to a human being.

Fetal stem cell research may ethically resemble either adult or embryonic stem cell research and must be evaluated accordingly. If fetal stem cells are obtained from miscarried or stillborn fetuses, or if it is possible to remove them from fetuses still alive in the womb without harming the fetuses, then no harm is done to the donor and such fetal stem cell research is ethical. However, if the abortion of fetuses is the means by which fetal stem cells are obtained, then an unethical means (the killing of human beings) is involved. Since umbilical cords are detached from infants at birth, umbilical cord blood is an ethical source of stem cells.

Yes. In contrast to research on embryonic stem cells, non-embryonic stem cell research has already resulted in numerous instances of actual clinical benefit to patients. For example, patients suffering from a whole host of afflictionsincluding (but not limited to) Parkinsons disease, autoimmune diseases, stroke, anemia, cancer, immunodeficiency, corneal damage, blood and liver diseases, heart attack, and diabeteshave experienced improved function following administration of therapies derived from adult or umbilical cord blood stem cells. The long-held belief that non-embryonic stem cells are less able to differentiate into multiple cell types or be sustained in the laboratory over an extended period of timerendering them less medically-promising than embryonic stem cellshas been repeatedly challenged by experimental results that have suggested otherwise. (For updates on experimental results, access http://www.stemcellresearch.org.)

Though embryonic stem cells have been purported as holding great medical promise, reports of actual clinical success have been few. Instead, scientists conducting research on embryonic stem cells have encountered significant obstaclesincluding tumor formation, unstable gene expression, and an inability to stimulate the cells to form the desired type of tissue. It may indeed be telling that some biotechnology companies have chosen not to invest financially in embryonic stem cell research and some scientists have elected to focus their research exclusively on non-embryonic stem cell research.

Another potential obstacle encountered by researchers engaging in embryonic stem cell research is the possibility that embryonic stem cells would not be immunologically compatible with patients and would therefore be rejected, much like a non-compatible kidney would be rejected. A proposed solution to this problem is to create an embryonic clone of a patient and subsequently destroy the clone in order to harvest his or her stem cells. Cloning for this purpose has been termed therapeutic cloningdespite the fact that the subject of the researchthe cloneis not healed but killed.

Underlying the passages of Scripture that refer to the unborn (Job 31:15; Ps. 139:13-16; Lk. 1:35-45) is the assumption that they are human beings who are created, known, and uniquely valued by God. Genesis 9:6 warns us against killing our fellow human beings, who are created in the very image of God (Gen. 1:26-27). Furthermore, human embryonic lifeas well as all of creationexists primarily for Gods own pleasure and purpose, not ours (Col. 1:16).

Many proponents of human embryonic stem cell research argue that it is actually wrong to protect the lives of a few unborn human beings if doing so will delay treatment for a much larger number of people who suffer from fatal or debilitating diseases. However, we are not free to pursue gain (financial, health-related, or otherwise) through immoral or unethical means such as the taking of innocent life (Deut. 27:25). The history of medical experimentation is filled with horrific examples of evil done in the name of science. We must not sacrifice one class of human beings (the embryonic) to benefit another (those suffering from serious illness). Scripture resoundingly rejects the temptation to do evil that good may result (Rom. 3:8).

No forms of stem cell research or cloning are prohibited by federal law, though some states have passed partial bans. Private funds can support any practice that is legal, whereas federal funds cannot be used for research on embryonic stem cell lines unless they meet the guidelines set forth by the National Institutes of Health in July 2009. For the latest developments you can stay informed via CBHD's newsblogwww.bioethics.com and thecoalition site http://www.stemcellresearch.org.

Editor's Note: This piece was originally published by Linda K. Bevington, MA, by CBHD in April 2005 under the title "Stem Cell Research and 'Therapeutic' Cloning: A Christian Analysis." The piece was subsequently revised and updated by CBHD research staff in August 2009.

Posted 4/2005, Updated 8/2009

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An Overview of Stem Cell Research | The Center for ...

Scientists reveal how stem cells defend against viruses

September 21, 2015 Left: Embryonic stem cells with silencing of viruses.Right: Removal of silencing machineries Cha1fa and Sumo2 resulting in the activation of viruses (in green). Credit: Jonathan Loh, A*STAR's Institute of Molecular and Cell Biology

Scientists from the Institute of Molecular and Cell Biology (IMCB), a research institute under the Agency for Science, Technology and Research (A*STAR), Singapore, have uncovered the mechanisms which embryonic stem cells employ to inhibit virus expression. The ground-breaking discovery could potentially advance stem cell therapeutics and diagnostics.

Several stem cell types including embryonic and haematopoietic stem cells are known to be capable of suppressing the activities of infected viruses and viral DNA residing in the host genome. This characteristic property, known as proviral silencing, however, has not been fully understood. In order to study this, a team of scientists from IMCB designed a novel assay which allowed them to screen all the genes present in embryonic stem cells.

Through the screening platform, the team identified 303 genes and elucidated 148 biological processes and pathways linked to proviral silencing, suggesting that proviral silencing is controlled by coordinated mechanisms involving multiple cellular pathways. Through a comprehensive analysis, the scientists concluded that two specific genes, Chaf1a and Sumo2, are the key factors linked to proviral silencing. The findings of the study were reported in the top-tier scientific journal, Cell.

Further studies on the roles of Chaf1a and Sumo2 in stem cell proviral silencing can shed new light on stem cells and virus biology that could translate into valuable therapeutic and diagnostic applications.

Dr Jonathan Loh, Principal Investigator of IMCB, said, "This is the first detailed study on proviral silencing in embryonic stem cells, and it helped us gain a deeper understanding of stem cells and its unique proviral silencing ability. With the new insights, we can better identify the good stem cells and use them more efficiently and safely in clinical therapies. We can also devise diagnostic approaches by studying the activities of the virus DNA within stem cells in various diseased conditions."

Prof Hong Wanjin, Executive Director of IMCB, said, "Fundamental research on human biology seeks to understand crucial biological processes occurring within humans in order to bring advancement in therapeutics and improve lives. With the growing importance of stem cell therapy, this study is a fitting example of how upstream research can potentially benefit and shape its applications."

Explore further: Stem cells born out of indecision

More information: Systematic Identification of Factors for Provirus Silencing in Embryonic Stem Cells, http://www.cell.com/cell/abstract/S0092-8674%2815%2901089-2

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Scientists reveal how stem cells defend against viruses

Embryonic stem cell research: an ethical dilemma | Europe …

A human embryo can split into twins or triplets until about 14 days after fertilization

Egg and sperm: some people believe an embryo must be fully protected from conception onwards (Wellcome Images/Spike Walker)

Human blastocyst on the tip of a pin: embryonic stem cells can be grown from cells found in the blastocyst (Wellcome Images/Yorgos Nikas)

Some people think an embryo deserves special protection from about 14 days after fertilization

Many patients could one day benefit from embryonic stem cell research

The rules controlling embryonic stem cell research vary around the world and have been the topic of much discussion

Embryonic stem cell research poses a moral dilemma. It forces us to choose between two moral principles:

In the case of embryonic stem cell research, it is impossible to respect both moral principles.To obtain embryonic stem cells, the early embryo has to be destroyed. This means destroying a potential human life. But embryonic stem cell research could lead to the discovery of new medical treatments that would alleviate the suffering of many people. So which moral principle should have the upper hand in this situation? The answer hinges on how we view the embryo. Does it have the status of a person?

Chapter 1 of this film introduces some of the key ethical arguments. Watch this film and others on our films page.

The moral status of the embryo is a controversial and complex issue. The main viewpoints are outlined below.

1. The embryo has full moral status from fertilization onwards Either the embryo is viewed as a person whilst it is still an embryo, or it is seen as a potential person. The criteria for personhood are notoriously unclear; different people define what makes a person in different ways.

Development from a fertilized egg into to baby is a continuous process and any attempt to pinpoint when personhood begins is arbitrary. A human embryo is a human being in the embryonic stage, just as an infant is a human being in the infant stage. Although an embryo does not currently have the characteristics of a person, it will become a person and should be given the respect and dignity of a person.

An early embryo that has not yet implanted into the uterus does not have the psychological, emotional or physical properties that we associate with being a person. It therefore does not have any interests to be protected and we can use it for the benefit of patients (who ARE persons).

The embryo cannot develop into a child without being transferred to a womans uterus. It needs external help to develop. Even then, the probability that embryos used for in vitro fertilization will develop into full-term successful births is low. Something that could potentially become a person should not be treated as if it actually were a person

2. There is a cut-off point at 14 days after fertilization Some people argue that a human embryo deserves special protection from around day 14 after fertilization because:

3. The embryo has increasing status as it develops An embryo deserves some protection from the moment the sperm fertilizes the egg, and its moral status increases as it becomes more human-like.

There are several stages of development that could be given increasing moral status:

1. Implantation of the embryo into the uterus wall around six days after fertilization. 2. Appearance of the primitive streak the beginnings of the nervous system at around 14 days. 3. The phase when the baby could survive if born prematurely. 4. Birth.

If a life is lost, we tend to feel differently about it depending on the stage of the lost life. A fertilized egg before implantation in the uterus could be granted a lesser degree of respect than a human fetus or a born baby.

More than half of all fertilized eggs are lost due to natural causes. If the natural process involves such loss, then using some embryos in stem cell research should not worry us either.

We protect a persons life and interests not because they are valuable from the point of view of the universe, but because they are important to the person concerned. Whatever moral status the human embryo has for us, the life that it lives has a value to the embryo itself.

If we judge the moral status of the embryo from its age, then we are making arbitrary decisions about who is human. For example, even if we say formation of the nervous system marks the start of personhood, we still would not say a patient who has lost nerve cells in a stroke has become less human.

If we are not sure whether a fertilized egg should be considered a human being, then we should not destroy it. A hunter does not shoot if he is not sure whether his target is a deer or a man.

4. The embryo has no moral status at all An embryo is organic material with a status no different from other body parts.

Fertilized human eggs are just parts of other peoples bodies until they have developed enough to survive independently. The only respect due to blastocysts is the respect that should be shown to other peoples property. If we destroy a blastocyst before implantation into the uterus we do not harm it because it has no beliefs, desires, expectations, aims or purposes to be harmed.

By taking embryonic stem cells out of an early embryo, we prevent the embryo from developing in its normal way. This means it is prevented from becoming what it was programmed to become a human being.

Different religions view the status of the early human embryo in different ways. For example, the Roman Catholic, Orthodox and conservative Protestant Churches believe the embryo has the status of a human from conception and no embryo research should be permitted. Judaism and Islam emphasize the importance of helping others and argue that the embryo does not have full human status before 40 days, so both these religions permit some research on embryos. Other religions take other positions. You can read more about this by downloading the extended version of this factsheet below.

Extended factsheet with a fuller discussion of the issues by Kristina Hug (pdf) EuroStemCell film "Conversations: ethics, science, stem cells" EuroStemCell factsheet on ethical issues relating to the sources of embyronic stem cells EuroStemCell factsheet on the science of embryonic stem cells EuroStemCell FAQ on human embryonic stem cells and their use in research EuroStemCell summaries of regulations on stem cell research in Europe Booklet for 16+ year olds about stem cells and ethics from the BBSRC Research paper on the ethics of embryonic stem cell research by Kristina Hug

This factsheet was created by Kristina Hug and reviewed by Gran Hermern.

Images courtesy of Wellcome Images: Egg and sperm by Spike Walker; Blastocyst on pin by Yorgos Nikas; Diabetes patient injecting insulin by the Wellcome library, London.

Other images from "Conversations : ethics, science, stem cells", a film by EuroStemCell.

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Embryonic stem cell research: an ethical dilemma | Europe ...

Researchers control embryonic stem cells with light

August 26, 2015 A colony of embryonic stem cells, from the H9 cell line (NIH code: WA09). Viewed at 10X with Carl Zeiss Axiovert scope. (The cells in the background are mouse fibroblast cells. Only the colony in the centre are human embryonic stem cells) Credit: Ryddragyn/ Wikipedia

UC San Francisco researchers have for the first time developed a method to precisely control embryonic stem cell differentiation with beams of light, enabling them to be transformed into neurons in response to a precise external cue.

The technique also revealed an internal timer within stem cells that lets them tune out extraneous biological noise but transform rapidly into mature cells when they detect a consistent, appropriate molecular signal, the authors report in a study published online August 26 in Cell Systems.

"We've discovered a basic mechanism the cell uses to decide whether to pay attention to a developmental cue or to ignore it," said co-senior author Matthew Thomson, PhD, a researcher in the department of Cellular and Molecular Pharmacology and the Center for Systems and Synthetic Biology at UCSF.

During embryonic development, stem cells perform an elaborately timed dance as they transform from their neutral, undifferentiated form to construct all the major organ systems of the body. Researchers have identified many different molecular cues that signal stem cells when to transform into their mature form, whether it be brain or liver or muscle, at just the right time.

These discoveries have raised hopes that taking control of stem cells could let scientists repair damaged and aging tissues using the body's own potential for regeneration. But so far, getting stem cells to follow instructions en masse has proven far more difficult than researchers once expected.

In recent years, scientists have found that many of the genes encoding these developmental cues constantly flip on and off in undifferentiated stem cells. How the cells manage to ignore these noisy fluctuations but then respond quickly and decisively to authentic developmental cues has remained a mystery.

"These cells receive so many varied inputs," said lead author Cameron Sokolik, a Thomson laboratory research assistant at the time of the study. "The question is how does the cell decide when to differentiate?"

To test how stem cells interpret developmental cues as either crucial signals or mere noise, Thomson and colleagues engineered cultured mouse embryonic stem cells in which the researchers could use a pulse of blue light to switch on the Brn2 gene, a potent neural differentiation cue. By adjusting the strength and duration of the light pulses, the researchers could precisely control the Brn2 dosage and watch how the cells respond.

They discovered that if the Brn2 signal was strong enough and long enough, stem cells would quickly begin to transform into neurons. But if the signal was too weak or too brief, the cells ignored it completely.

"The cells are looking at the length of the signal," Thomson said. "That was a big surprise."

To learn how stem cells were able to weed out fleeting Brn2 signals but respond to persistent ones, co-senior author Stanley Qi, PhD, and co-author Yanxia Liu, PhD, both now at Stanford University, used the CRISPR-Cas9 gene editing system to add a fluorescent tag to the transcription factor Nanog, which normally acts as a brake on differentiation. This protein could then be used as a read-out on the cells' decision-making.

The team discovered that Nanog itself is actually key to the cells' impeccable sense of timing. When the Brn2 signal turns on, it disrupts a molecular feedback loop that keeps the cell stable and undifferentiated. In response, Nanog protein levels start to drop. However, the protein takes about four hours to dissipate completely, which makes Nanog an excellent internal stop-watch. If the Brn2 signal is a fluke, Nanog levels can quickly rebound and the cell will do nothing. On the other hand, if Nanog runs out and the Brn2 signal is still on, "it's like a buzzer goes off," Thomson said. "And once it goes, it really goes - the cells rapidly start converting into neurons."

Thomson believes that similar timer mechanisms may govern stem cell differentiation into many different tissues.

"It's hard for a cell to be both tolerant and fast, to reject minor fluctuations, but respond very precisely and sharply when it sees a signal," he said. "This mechanism is able to do that."

Thomson is a UCSF Sandler Fellow and Systems Biology Fellow. Since 1998, these unique fellowship programs have enabled UCSF to recruit young researchers straight out of graduate school to pursue ambitious high-risk, high-reward science.

Thomson's ambitious big idea is to use the light-inducible differentiation technology his group has developed to study how stem cells produce complex tissues in three dimensions. He imagines a day when researchers can illuminate a bath of undifferentiated stem cells with a pattern of different colors of light and come back the next day to find a complex pattern of blood and nerve and liver tissue forming an organ that can be transplanted into a patient.

"There's lots of promise that we can do these miraculous things like tissue repair or even growing new organs, but in practice, manipulating stem cells has been notoriously noisy, inefficient, and difficult to control," Thomson said. "I think it's because the cell is not a puppet. It's an agent that is constantly interpreting information, like a brain. If we want to precisely manipulate cell fate, we have to understand the information-processing mechanisms in the cell that control how it responds to the things we're trying to do to it."

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Researchers control embryonic stem cells with light