Posts Tagged ‘human stem cells’

What You Should Know About The Stem Cell Research Controversy

Saturday, July 18th, 2009

stem cell controversy

One of the first things President Barack Obama did upon taking office was lift the controversial ban on stem cell research. The National Institute of Health informs us that human stem cells are very important to scientific research because they have the potential to differentiate into almost any type of cell, tissue or organ in the body. Additionally, stem cell therapies may make it possible for humans to regenerate damaged parts of their own bodies more naturally, without using artificial materials or drugs. In the future, scientists hope to treat cancer, Parkinson’s, heart disease and diabetes with stem cells.

In an embryo that is just three days old, stem cells are found that will later transform into the heart, lungs, skin, tissues, bone marrow, muscle and brain. Advocates of stem cell research believe that there may be a way to generate replacement cells for parts of the body lost through injury, disease or aging. What makes stemcells different than blood, muscle or nerve cells is their innate ability to replicate for months in a laboratory setting. Scientists are hopeful about the potential for long term rejuvenation using these self-renewing human stem cells.

There are two varieties used in modern stem cell research: stem cells embryonic and stem cells adult. Embryonic stem cells are cultivated in a Petri dish from in vitro fertilization. This type of stem cell is extremely versatile and can differentiate into more than 220 cell types in the body for more than a year in a research setting, which is promising for many future medical treatments. Scientists are still trying to understand why embryonic cells are so much more flexible than adult stem cells. Some Americans feel it is inherently wrong to tamper with human cells, by creating, manipulating and destroying fertilized cells that could otherwise continue to grow into human life within a host.

While stem cell research has been full of controversy in America, other nations, notably Iran, have nothing against stem cell research at all. “Policies that may be classified as liberal in the American political system seem to be common sense to Iranian politicians,” explains Hassan Ashktorab of the Howard University Cancer Center in Washington, DC. While George W. Bush banned research on fetal stem cells, Iran’s Ayatollah Khamenei embraced the modern science. While human cloning is still condemned in Iranian culture, they believe it is their duty to do their best to prevent illness and protect human life.

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Pointers About Embryonic Stem Cells

Tuesday, July 14th, 2009

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What if human cells could be stimulated to regenerate body parts or repair damaged tissues in the same way that earthworms or planarians can? Embryonic stem cells are the most versatile type of cells to work with because they can differentiate into any kind of cell in the body. Adult stem cells are more tissue-specific, although the body responds better to its own stem cells in therapy. In order for stem cell therapies to work, the body’s immune system must be suppressed so there is no reaction to the transplanted cells. Additionally, scientists must take special care to ensure the cells proliferate enough to heal the body but not so much that cancer develops.

There are two types of stem cells research. One involves the use of embryonic stem cells and the other involves the use of adult stem cells. The embryonic cells come from a one-week-old mass of cells called a blastocyte. Many of the fetal stem cells come from in vitro fertilization patients who had leftovers after receiving fertility treatment. A single embryo can create enough lines of cells for use in Stem cell therapies. Tissue from aborted fetuses is not regularly used in stem cell research. What makes an embryonic stem cell so special is that it can develop into any organ or tissue. Stem cell therapies can help treat diseases like heart or Parkinson’s disease, as well as burn or stroke victims and patients with spinal cord injuries, muscular dystrophy, arthritis and diabetes.

Though fetal stem cells have been the focus of most of the research, scientists are discovering that adult stem cells are particularly effective in transplants. For instance, they can grow an entire organ, a section of the windpipe or a section of tissue to offer the human host, which will most certainly accept the new cells derived from its own DNA. Another alternative to using embryonic stem cells is under current examination. It involves stimulating adult stem cells to revert back to their “pluripotent” state, which allows them to proliferate again. It’s believed that humans may be able to regrow lost skin or repair other tissues this way, although more research is needed before human trials can begin to prove this theory.

In recent stem cell news, the Harvard Stem Cell Institute (HSCI) and Massachusetts General Hospital discovered that a medication for bone marrow cancer can affect osteoporosis in mice by acting upon mesenchymal stem cells, which differentiate into several tissue types. “Stem cell therapies are often thought of as putting new cells into the body,” said David Scadden, director of the MGH Center for Regenerative Medicine, “but this study suggests that medications can turn on existing stem cells that reside in the body’s tissues, acting as regenerative medicines to enhance the body’s own repair mechanisms.” Therefore, instead of relying on controversial embryonic stem cells, a person’s own stem cells can be used in the treatment.

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An Overview Of The Human Embryonic Stem Cells

Saturday, July 11th, 2009

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Human embryonic stem cells are a relatively new field of research. The first human stem cell was isolated for experiments by Dr. James Thomson from the University of Wisconsin in 1998. A ban on federal funding for research involving fetal stem cells further stymied research possibilities for many years until former President Bush allowed some of the frozen stem cell lines to be used for research, rather than discarded. Then President Obama lifted the federal ban entirely. As a result, human stem cell research is still in its early stages, but human clinical trials are expected to begin this summer.

There are three classes of human embryonic stem cells. A fertilized egg is “totipotent,” which means that it can give rise to any type of cell in the body. A “pluripotent” stem cell can become any type of cell in the body (except for those required to develop a fetus). “Multipotent” cells can give rise to a small number of other cell types. These fetal stem cells are usually taken from embryos and used to create “stem cell lines,” which can be grown forever in a laboratory setting. While most stem cells come from young embryos that are just 3 to 5 days old, some pluripotent stem cell lines may be derived from fetal tissue that is beyond 8 weeks old.

There are several traits that make human embryonic stem cells preferable for stem cell therapies. For one, these early developmental cells are a blank canvas. These cells have no particular tendency to become anything specific but may be encouraged to become one of 200+ cell types. Additionally, fetal stem cells can remain in this protean, undifferentiated state for long periods of time and may divide or self-renew indefinitely. Therefore, it’s easier to create mass quantities of embryonic stem cells for use in adult stem cell research.

Even though research using human embryonic stem cells was limited to select states that passed ballot initiatives, underground, privately-funded scientists have been working diligently since 1998 to find ways to use not just fetal stem cells but also adult human stem cells. It was previously believed that embryonic stem cells were versatile, able to become any of 200+ cell types and that adult stem cells were confined to only replicating more specialized cells of a similar nature. In late 2007, scientists found a way to reprogram adult stem cells to behave like embryonic stem cells that will form a number of other tissues, rather than just the tissue it was derived from. More studies are needed to determine whether these manipulated cells are safe for use in humans, but the findings are significant.

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An Overview Of The Pros And Cons Of Adult Stem Cells

Sunday, July 5th, 2009

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There’s good news and bad news about adult stem cells. The good news is that human trials are officially here for adult stem cell research. As of April 1, 2009, the first stroke patient was treated with his own stem cells. The bad news is that even if his treatment proves to be successful, researchers will still be prompted to run Phase II trials and Phase III trials to determine long-term safety. It could be another 10 years before stem cell therapies are FDA-approved for the masses. Even so, the portent for this relatively new field of medicine is rather exciting.

There are some advantages to using adult stem cells over embryo-derived stem cells. For one, adult cells are easier to harvest, as they can come from skin, muscle, bone marrow and fat. Often those treated with their own stem cells will not suffer immune system rejection. It’s also easier to encourage these already specialized cells to differentiate the way the scientists want them to, which is impressive considering they’re still not 100% sure what causes a cell to become a certain organ or tissue. Lastly, donated adult stemcells clear up the stem cell controversy surrounding the destruction of human embryos in the name of science.

Mice are not people. We know this. Even so, it’s hard not be excited that the first mouse has successfully regrown muscles and regenerated damaged tissue thanks to adult stem cells. Researchers from the University of New South Wales say the mice were given a gene making them resistant to chemotherapy, which clears out damaged cells and encourages new stem cells to take hold. “What has been the realm of science fiction is looking more and more like the medicine of the future,” said Peter Gunning, one of the study’s co-authors.

What moral grounds are scientists subject to adhere to? This is one of the controversies surrounding adult stem cells. Once techniques for creating a new stem cell are in place, who’s to say the scientist won’t fall naturally into therapeutic cloning or even human cloning? If a human can regrow a limb like a salamander, will there be some so curious as to create a human-animal hybrid? Is there a danger in manipulating germs, diseases and mutagens in Petri dishes that could lead to more resistant strains? Will researchers exercise enough patience to ensure the long-term safety of their products containing human stem cells? Can our earth sustain a population that can live even longer and regenerate? To what extent are we playing God?

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