Cloning using skin cells rather than stem cells

reposted & edited from: http://news.bbc.co.uk/1/hi/uk/7099758.stm
WASP comments are in bright green; highlights in blockquotes (yellow).

Dolly scientist abandons cloning

An egg being collected

The scientist who controversially created Dolly the sheep is abandoning the cloning of human embryos in stem cell research.

Professor Ian Wilmut, of Edinburgh University, believes a rival method developed in Japan holds the key to curing serious medical conditions.

The new method creates stem cells from fragments of skin and removes the need to use human embryos.

Prof Wilmut developed a cloning technique which involved creating stem cells - which have the potential to be grown into any cell in the human body - from human embryos.

Building blocks

Embryonic or stem cells are widely regarded as the most flexible cells in the body and are seen as the body's building blocks.

Wilmut has now embraced a technique developed by Prof Shinya Yamanaka of Kyoto University, Japan, that involves genetically modifying adult cells to make them almost as flexible as stem cells. The research has been conducted on mice.

The work is due to be published in a scientific journal on Tuesday. Prof Wilmut said his own research team held a meeting at which it was agreed the Japanese method had more potential than the use of embryonic cells.

He said:

"The work which was described from Japan of using a technique to change cells from a patient directly into stem cells without making an embryo has got so much more potential.

"Even though it's only been described for the mouse, when we were considering which option to pursue, whether to clone or whether to copy the work in Japan, we decided to copy the work in Japan."

More acceptable

Speaking to the Daily Telegraph, Prof Wilmut said: "Before too long we will be able to use the Yamanaka approach to achieve the same, without making embryos. In the long term, direct reprogramming will be more productive.

"I decided a few weeks ago not to pursue nuclear transfer [the method used to create Dolly the sheep]," and he admitted the new method "was easier to accept socially".

Dolly the sheep was unveiled to the world in 1997

The eventual aim is to grow replacement tissue as body parts become worn out.

There is some way to go before Prof Yamanaka's method can be used to grow tissue for transplantation as the resulting cells are unstable and potentially cancerous.

But Professor Wilmut believes that within five years the new technique could provide a better and ethically more acceptable alternative to cloning embryos for medical research.

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Who says stem cell research is wrong? Who says it's right?

reposted from: nature.com

Who says stem cell research is wrong? Who says it's right?

Some opponents of stem cell research argue that it offends human dignity or harms or destroys human life. Proponents argue that easing suffering and disease promotes human dignity and happiness, and that destroying a blastocyst is not the same as taking a human life.

Photo credit: Getty

Laboratory research on adult stem cells is generally uncontroversial. Research with human subjects becomes controversial because some experimental "therapies" could harm patients. Debate can be acrimonious between researchers who want to perform additional studies on animals to try to better understand risks to humans, and those who don't want to delay testing procedures that might help patients.

Most opponents to embryonic stem cell research think that it is wrong to destroy a 2- to 6-day-old embryo, even if it is not destined to start a pregnancy. Others argue that it is immoral not to do this research, if doing so could lead to treatments for disease. The groups disagree as to whether an early embryo deserves the same protection as a fetus or an adult human.

The acquisition of unfertilized human eggs is another area of controversy. The procedure to retrieve eggs from women requires a series of drugs and surgery. Women who donate eggs face a small but real risk of death and are certain to endure discomfort. In most countries, women can be paid to donate eggs to infertile couples, but many ethicists, lawyers and women's rights activists feel that women should not be compensated for donating eggs for research. Other ethicists, lawyers and women's rights activists feel that they should, at least to compensate for time lost from work and other costs to them.

To surmount the supply and ethical problems of acquiring human eggs, some researchers have proposed inserting human nuclei into animal eggs. Any embryonic stem cells derived would not be used for therapies directly but instead used to conduct research that could lead to therapies. Other researchers hope to make research-grade materials through cell fusion or genetically engineering other types of cells.

Regulatory agencies in the UK have launched a public discussion as to whether human-animal hybrids should be created. Researchers must agree not to let the embryos grow past 2 weeks, and the researchers must argue convincingly that their experiments address important questions that could not be answered any other way. However, some people object that mixing human nuclei with animal eggs offends human dignity or that scientists might not follow the regulations set for these experiments.

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How does a fertilized egg develop?

reposted from:nature.com

How does a fertilized egg develop?

An adult human contains trillions of cells of more than 200 types. All these cells (plus the many, many more cells that are shed throughout life) can be traced back to the fertilized egg, the one cell that can, ultimately, create every type of cell in the body.

Photo credit: Jenny Nichols / Institute for Stem Cell Research

The most versatile stem cells occur earliest in life. As a fertilized human egg divides, it first becomes a solid ball of cells, the morula. Next, about five days after fertilization, it becomes a hollow ball, the blastocyst. The cells of the outer layer of the blastocyst eventually form part of the placenta.

Inside the ball is a small clump of cells, the inner cell mass, that will form all the tissues in the body. When isolated from blastocysts created by in vitro fertilization (IVF) and grown in culture, these are the cells known as embryonic stem cells (ES cells).

The floating blastocyst takes another day or so to attach to the wall of the uterus and begin to draw nutrients from it. The basic structure of the placenta forms in about three weeks.

Well before then the embryonic cells are already "too old" to make ES cells. They have already become committed to more restricted fates. The initial flat sheet of embryonic cells folds and twists and grows to form a recognizable embryo, with a rudimentary head and a central cavity surrounded by three "layers" of cells. The cavity lengthens to form the gut. Cells in the innermost layer, the endoderm, make the lining of the gut and associated organs like the pancreas and liver. Cells in the middle layer, the mesoderm, form pretty much everything else on our inside: muscle, bone, heart, and kidneys, and all the connective tissues in between. Those cells in the outermost layer, the ectoderm, become skin and brain.

By about eight weeks after fertilization, all the major structures and tissues of a human body, including the heart and even the eyelids, are in place, although they've still got a lot of developing to do. The result, less than 4 centimetres (1.5 inches) long, is now called a fetus.

As pregnancy continues, stem cells become more and more specialized. Fetuses and adults have many types of stem cells, but each type generally makes fewer different kinds of cells than stem cells from earlier stages in development. The so-called bronchoalveolar stem cells found in the lungs in adults, for example, make only cells found in particular parts of the lung.

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What are stem cells?

reposted from: nature.com

What are stem cells?

Stem cells build tissue when and where it's needed.

Photo credit: Don Bishop / Getty

Without stem cells, wounds would never heal, your skin and blood could not continually renew themselves, fertilized eggs would not grow into babies, and babies would not grow into adults. Stem cells are quite unlike the specialized, or differentiated, cells in your body — such as the nerve cells, muscle cells and blood cells that enable you to function.

In contrast, they are the body's silent reserves. At any given moment, many of the stem cells in your body won't be doing very much. They will only spring into action when you need either to produce more stem cells or make more of other, specialized types of cells. And they're not just found in people. All multicellular organisms, from plants to humans, need stem cells.

Usually, when a stem cell divides into two, one daughter cell goes on to make a more specialized type of cell, or even gives rise to several different cell types. The other daughter cell remains a stem cell, ready to produce more stem cells when they are needed. Only stem cells have this versatility, although some fully specialized cells, such as liver cells, can divide to give more cells exactly like themselves.

A fertilized egg is the ultimate stem cell, as it is the source of every type of cell in the body, from oxygen-carrying red blood cells to electricity-conducting nerve cells and throbbing heart muscle cells.

But of course this doesn't happen all at once. As the fertilized egg divides to make an embryo, cells become specialized gradually.

Within three to six days after a human egg is fertilized, it has grown into a ball of a few hundred cells called a blastocyst. Within this ball lie a small number of cells that will go on to develop into the embryo. Scientists have learned to extract these stem cells from a thickening in the blastocyst called the inner cell mass and to grow them in the laboratory. These are known as embryonic stem cells or ES cells, and they have the potential to produce all the cell types in the human body. When a blastocyst implants in a woman's uterus, the cells of the inner cell mass will keep on dividing and differentiating into the earliest types of embryonic cells. Human ES cells in culture are not created from eggs that have been fertilized inside a woman's body. They come from the inner cell masses of 'spare' blastocysts that have been created in the laboratory as part of in vitro fertilization (IVF) programmes.

Less than three weeks after a human egg has been fertilized, these most flexible of stem cells have disappeared and embryonic cells become gradually more restricted in their potential. Instead of dividing to make one more specialized daughter cell and a back-up all-purpose stem cell, later embryonic cells are more likely to make two types of more differentiated cells when they divide. At this stage, the embryo's cells have 'committed' to become one of three general types of tissue that each has distinct types of stem cells. Many of these persist into adult life. As embryonic development continues, cells become even more specialized, forming recognizable tissues such as heart, muscle and blood.

In adults, dozens of stem-cell types have been described; more remain to be discovered. These stem cells are called tissue-specific as they will normally only replace one particular tissue. They are also sometimes called adult stem cells. The best understood are the stem cells that grow new blood cells, those that renew the skin, those that renew the gut lining, and those that can grow new skeletal muscles. Stem cells in the bone marrow make blood cells and have been used therapeutically for years. These are the cells that make it possible for a bone marrow transplant to renew a person's complete blood system.

Scientists across the world are trying to figure out exactly what these stem cells are capable of becoming in the lab and in the body; right now, however, tissue-specific stem cells appear to be specialists, quite good at making a few types of cells. Stem cells found in bone marrow naturally make new red blood cells and new white blood cells, for instance, but not new brain cells, at least, not robustly. Stem cells occurring in the brain make new neurons plus the cells that support them, but they don't seem to make muscle cells.

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President's Theology Limiting Medical Research

Atheist Revolution repost the press release from The Secular Coalition for America calling on President Bush not to veto the Stem Cell Research Enhancement Act.

Friday, June 08, 2007

The Secular Coalition for America has issued an excellent press release (which I am reproducing in its entirety below) pointing out what is at stake with the Stem Cell Research Enhancement Act. This is the same issue they recently took up by asking us to e-mail President Bush to urge him not to veto this bill. What I really like about this press release is how it frames the issue as Bush imposing his theology on all Americans by impeding medical research that could benefit us all. I believe that this is an accurate and terrifying characterization.

“It is Cruel for the President’s Theology to Influence Medical Research”
President Bush: Sign the Stem Cell Research Enhancement Act - Do not Impede Medical Research
Statement by Secular Coalition for America Director Lori Lipman Brown

Washington, DC – June 7, 2007 -- The Secular Coalition for America strongly urges President Bush to sign the Stem Cell Research Enhancement Act (S.5), which passed the House today. Medical experts agree that embryonic stem cell research has great potential to help alleviate or even cure many devastating medical conditions.

Last year, President Bush falsely equated each embryo with “unique human life with inherent dignity,” and claimed that stem cell research supported “the taking of human life.” In fact, the stem cells used in medical research are actually taken from blastocysts, spheres of 100-200 cells five to six days after fertilization of a human egg. Imbuing such collections of cells with the qualities of an individual fully formed person, is a theological position, not a scientific or medical one.

The Secular Coalition for America believes it is cruel for the President's personal theology to dictate the limits of medical research.

The President now has a chance to allow the National Institutes of Health to use the most promising materials in its research. These excess cells, developed during in vitro fertilization procedures, are scheduled to be destroyed. The Secular Coalition for America calls on the President to allow these cells to be diverted away from the trash bin, and towards what may prove to be lifesaving uses.

According to recent polls the majority of Americans support the use of embryonic stem cell research. The Secular Coalition for America joins with the majority of the members of both houses of Congress and with the majority of Americans, when we ask of President Bush to please not allow his personal religious belief to interfere with advances which may someday lead to the alleviation of tremendous human suffering.

If you have not already contacted Bush about this important issue, please consider doing so now.

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