science and nature – nature online – science news

human stem cells

In January 2009, Geron Corporation obtained FDA-approval to begin its first human clinical trial involving human embryonic stem cells. They’re planning to study 8 to 10 individuals who have sustained recent spinal cord injuries for one year. Pending a successful run, the FDA may approve a second and third round of follow-up studies. Naturally, the long-term safety of stem cell therapies must be studied before widespread drugs or treatments can prosper. Some estimates say it could take 10 years or more before we see groundbreaking use of stem cells.

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.

Human embryonic stem cells have traits that make them preferable in stem cell therapies. Early developmental cells extracted from “blastocytes,” which are cell masses that are less than two weeks old, are in a state that is very flexible. These cells are essentially clean slates that have no inherent tendency to become one cell type or another, but over time they will eventually go on to differentiate into an organ or specific tissue. As of this writing, scientists aren’t sure what exactly causes cells to mature into certain types but this will be an area of particular interest.

Since there is much stem cell controversy surrounding the use of human embryonic stem cells, the research in this field has been largely stymied by public protests and government repudiation. President George W. Bush reaffirmed a federal ban on funding stem cell research, although he allowed scientists to use some of the preexisting frozen embryo stem cell lines that would otherwise be discarded. President Obama has allocated funding in his budget for both embryonic and adult stem cell research, which has opened many new doors.

waki Uncategorized adult stem cell research, fetal stem cells, human embryonic stem cells, human stem cells, stem cell therapies

against stem cell research

Several studies have indicated that the human body may have regenerative properties if given the right circumstances. For example, a child under ten years old may be able to regrow a lost fingertip if the wounds aren’t stitched up to prevent the regrowth. If the membrane surrounding one’s rib is left intact, a damaged rib can regenerate. Scientists also speculate that livers and kidneys have some regenerative abilities as well. To further study this realm of science, we must rely on stem cell research. However, there is much stem cell controversy blocking the path to enlightenment.

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.

Stem cell research holds many promises. Stem cell therapies are being used to treat type 1 diabetes and strokes with a degree of success. Perhaps in the future, scientists will be able to create healthy heart tissue in the lab and transplant it into their patients, rather than relying on a short supply of donors. Researchers at the University of Rochester are also running trials to repair broken or degenerating bones. With continued focus and funding, we’re likely to see many more exciting breakthroughs in this field.

waki Uncategorized adult stem cell research, against stem cell research, fetal stem cells, human stem cells, stem cell controversy, Stem Cell Research, stemcells

fetal stem cells

In 1981, British scientist Sir Martin Evans isolated the first animal embryonic stem cells. In 1998, American scientist Jamie Thomson led a team that derived the first human stem cells. While little was known about stem cells in animals or people, researchers saw great potential in getting to know these versatile cells, which could hold the key to regeneration and the creation of natural replacement tissue.

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.

The latest stem cell news is that the FDA has approved the use of embryonic stem cells to treat spinal cord injuries, with human trials expected to begin as early as this summer. Geron Corporation has produced masses of specialized cells called “oligodendrocyte precursor cells,” which can be injected into the spine at the site of an injury to produce myelin and stimulate nerve regrowth. The human trials will involve 8 to 10 patients who have sustained complete spinal cord injuries below the third to tenth vertebra. Patients will be selected who have suffered their injuries within 14 days, scientists say, and patients will be monitored for signs of improvement for at least one year.

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.

waki Uncategorized embryonic stem cells, fetal stem cells, human stem cells, mesenchymal stem cells, stem cell news, stem cell therapies, stem cells research

stem cell research debate

The stem cell research debate has spanned numerous decades, with presidents like George HW Bush, Ronald Reagan and George W. Bush rejecting funding science that tampered with human embryos, and presidents like Bill Clinton and Barack Obama appropriating money toward an end that justifies the means. If a primitive bundle of cells can be used to save thousands or millions of lives and alleviate suffering, then is it worth it? Or does embryonic stem cell research cross the line between man and God?

When does human life begin? This is the quintessential theological question behind embryonic stem cell research. Devout Catholics and Protestants will tell you, “Human life begins at conception, at the very moment when sperm and egg come together. Development from there on out should be left up to God and God only.” They argue the problem is that embryos are killed in the process of harvesting stem cells, therefore aborting the developing embryo. In a speech on August 9, 2001, former President George W. Bush explained, “While we must devote enormous energy to conquering disease, it is equally important that we pay attention to the moral concerns raised by the new frontier of human embryo stem cell research. Even the most noble ends do not justify any means.” Pope Benedict XVI went so far as to say human stem cell research was “not only devoid of the light of God but also devoid of humanity.”

Scientists working with fetal stem cells argue they’re using primitive “blastocyte” cells fertilized in Petri dishes that are typically 3-5 days old and have not formed nerves or brain cells yet. The general consensus is that fetuses are not capable of feeling and processing pain until the third trimester, or 28 weeks, when the thalamocortical connections are developed. To others, it’s a matter of practicality. James Thomson, the first scientist to do embryonic stem cell research, told MSNBC’s Alan Boyle in June 2005, “The bottom line is that there are 400,000 frozen embryos in the United States, and a large percentage of those are going to be thrown out. Regardless of what you think the moral status of those embryos is, it makes sense to me that it’s a better moral decision to use them to help people than just to throw them out. It’s a very complex issue, but to me it boils down to that one thing.”

Lately, little attention has been paid to embryonic stem cell research as more researchers set their sights on using umbilical cord stem cells instead. Perhaps the time span where the federal government refused to fund research involving fetal stem cells pushed scientists to find innovative ways to circumvent the law; or perhaps it was the realization that an adult human body would respond better to its own stem cells, rather than from a foreign embryo’s stem cells, that caused the shift.

waki Uncategorized against stem cell research, embryonic stem cell research, fetal stem cells, Stem Cell Research, stem cell research debate