It Takes All Kinds
The discovery of new sources of stem cells is great news. It's not a reason to neglect the funding of embryonic stem cell research.
This article is reprinted from The American Prospect.
Since President Bush’s veto of the Stem Cell Research Enhancement Act last year, scientists have made great research strides in the field. But as much as stem cell research has advanced scientifically, politically, things have stayed the same.
Federally funded stem cell researchers are still limited to only 21 older and potentially less useful stem cell lines, while scientists in other countries have access to a newer and larger variety. Recent scientific advances, including deriving stem cells from eggs and amniotic fluid, show the promise of the research. But they cannot serve as replacements for robust support for embryonic stem cell research.
Stem cell research should not be pursued in bits and pieces; comprehensive support is necessary to truly advance the science. Congress will be bringing the Stem Cell Research Enhancement Act back up for a vote this year, in the hopes of giving scientists access to the best tools we have in the race for life-saving cures.
Politicians tend to characterize the stem cell debate as embryonic versus adult stem cells, but the scientific reality is far different. Scientists do not think of research using embryonic and adult stem cells as separate enterprises, but rather as different tools in regenerative medicine — the use of cells from a variety of sources to cure diseases, learn more about human development, and more effectively develop drugs.
Researchers understand that different types of cells will prove useful for different purposes. Certain diseases or injuries may require treatment with adult or cord blood stem cells, while others will respond better to treatments with embryonic stem cells. Most importantly, research on one type of stem cell helps scientists working with all types of cells; as adult stem cell researcher Dr. David Scadden commented, “adult stem cell therapies will be bettered by the study of embryonic stem cells.” Conversely, hindering any type of stem cell research will slow research in other areas as well.
The recent announcement by scientists that they have discovered stem cells in amniotic fluid is very promising news. These new stem cells can be safely obtained through either amniocentesis or from the placenta, grow at a fast rate, become many of the cells in the human body, and provide a genetic match for the newborn child, thus reducing the chance of tissue rejection.
Yet, as the scientists who conducted the research made clear, they will not replace embryonic stem cells. There are still questions regarding how many different types of cells these new stem cells can become; stem cell scientist Dr. Robert Lanza commented that, “the [new stem cells] can clearly generate a broad range of important cell types, but they may not do as many tricks as embryonic stem cells.” Unlike embryonic stem cells, which can become any type of cell in the human body, the amniotic-fluid cells appear to be multipotent; they can become many types, but not all.
Amniotic-fluid stem cells will also not be as helpful for answering questions about early human development, which scientists consider to be one of the most important potentials of embryonic stem cell research. And it will take years for scientists to reproduce these new stem cells and determine how to use them clinically.
Meanwhile, scientists also recently announced that they had derived stem cells through parthenogenesis, which coaxes an unfertilized egg into developing as if it were fertilized. The cells derived from this process appear to have similar characteristics to embryonic stem cells, but unfortunately suffer from several drawbacks. Such cells have two sets of genes from the egg, instead of one set from the egg and one set from the sperm. This altered set of genes could lead to poor cell growth, abnormal cell development or cancer, and increases the risk of duplicate mutant genes that could cause additional problems. Also, parthenogenesis could only be used to develop stem cells that are genetic matches for women, and attempts to develop stem cells from sperm have proven more difficult.
Scientists will need additional time and resources to determine how to efficiently isolate and manipulate new types of stem cells, but they continue to make tremendous advances in the use of embryonic stem cells now. Researchers have used embryonic stem cells in laboratory animals to treat paralysis, slow vision loss, and reverse some of the symptoms of Parkinson’s disease. They have used human embryonic stem cells to create cardiovascular precursor cells that could lead to treatments for heart diseases, T-cells that could lead to a cure for AIDS, and insulin-secreting cells that could lead to a cure for diabetes. And there is a ready supply of 400,000 excess embryos stored in fertility clinics around the country.
In short, embryonic stem cells are still the most medically promising type of stem cells because of their ability to differentiate into any cell in the human body. Recent advances in embryonic stem cell research coupled with the discovery of new sources of stem cells only underscore the potential of this life-saving research.
The American people have also demonstrated tremendous support for this science — 56 percent want Congress to pass the Stem Cell Research Enhancement Act, and during the 2006 midterm election supporters of embryonic stem cell research won 62 percent of their races against opponents of the research. Congress already passed this legislation once with broad bipartisan support, only to see President Bush veto it. With all the scientific advances since then, one might expect to see this legislation advance as well.
This article is available on The American Prospect website.
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