Human stem cells

New source of stem cells found in
Amniotic fluid and placenta tissue

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Types of stem cells:

There were originally believed to be only two different types of stem cells:

However, research using adult stem cells has been underway for decades whereas studies using embryonic stem cells only began when the cells were first isolated in 1988. Thus, adult cells are already being used in clinical human trials of treatments and cures, whereas trials using embryonic stem cells are still many years away.

A National Institutes of Health news release states:

"...research involving human pluripotent stem cells...promises new treatments and possible cures for many debilitating diseases and injuries, including Parkinson's disease, diabetes, heart disease, multiple sclerosis, burns and spinal cord injuries. The NIH believes the potential medical benefits of human pluripotent stem cell technology are compelling and worthy of pursuit in accordance with appropriate ethical standards." ₁

Now, a third type of stem cell has been isolated. They can be harvested from amniotic fluid which surrounds the fetus during pregnancy, or from the placenta which is delivered after birth and routinely discarded.

Amniotic/placental stem cells:

In 2005, researchers at the University of Pittsburgh discovered that embryo-like stem cells could be obtained from the placenta. They are called "amniotic epithelial cells" after the amnion -- the outer membrane of the placenta's amniotic sac. Stephen Strom, an associate professor of pathology at the Pitt medical school and a researcher at the university’s McGowan Institute for Regenerative Medicine said:

"We think it would be easier to get these to the clinic than [embryonic stem] cells. [They were coaxed to differentiate] into several different tissue types, including liver cells, neurons, heart cells, pancreatic cells with the potential to produce insulin, and glial cells which form part of the nervous system." ₂

Each placenta contains about 300 million amniotic epithelial cells that could potentially be expanded to between 10 and 60 billion cells.

Also in 2005, Dr. Dario Fauza of Boston's Children's Hospital discovered that amnionic fluid stem cells might be used to treat a range of birth defects. ₃

A study released in 2007-JAN by North Carolina’s Wake Forest University School of Medicine and Harvard University shows that this third type of stem cells,  obtained from amniotic fluid, seem to combine the best features of both embryonic and adult stem cells:

They can double in number every 36 hours. They can divide at least 250 times without mutating and without forming tumors. They have been converted into bone, heart muscle, blood vessels, fat, nerve and liver tissues in lab mice. Unlike embryonic stem cells, they cannot reproduce indefinitely.

Dr. Anthony Atala, head of the Institute for Regenerative Medicine at Wake Forest University said:

"It has been known for decades that both the placenta and amniotic fluid contain multiple progenitor cell types from the developing embryo, including fat, bone, and muscle. ... We asked the question: 'Is there a possibility that within this cell population we can capture true stem cells?' The answer is yes."

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The potential of amniotic stem cells:

There is a real possibility that amniotic stem cells might be routinely harvested from pregnant women, and be banked for future use. Later, if a child or adult becomes ill or injured, they would be able to draw on these stem cells for treatment or a cure. The cells could be coaxed to convert into the desired type of cell, caused to replicate, and finally to produce a brand new organ for transplant. Since the DNA of the stem cells are a perfect match to the child's or adult's DNA there would be no risk of rejection.

Ethical aspects of amniotic/placental stem cells:

The pro-life community has not yet responded with its thoughts on this new source of stem cells. We can conceive of two objections to this line of research that they might have: