Archive for August, 2009
Creation Of Multiple Types Of White Blood Cells Directly From Embryonic And Adult Stem Cells
From MedicalNewsToday.com
In an advance that could help transform embryonic stem cells into a multipurpose medical tool, scientists at the University of Wisconsin-Madison have transformed these versatile cells into progenitors of white blood cells and into six types of mature white blood and immune cells.
While clinical use is some years away, the new technique could produce cells with enormous potential for studying the development and treatment of disease. The technique works equally well with stem cells grown from an embryo and with adult pluripotent stem cells, which are derived from adult cells that have been converted until they resemble embryonic stem cells.
If the adult cells came from people with certain bone marrow diseases, the new technique could produce blood cells with specific defects. It could also be used to grow specific varieties of immune cells that could target specific infections or tumors.
The likely most immediate benefit is cells that can be used for safety screening of new drugs, says study leader Igor Slukvin, an assistant professor in the university’s Department of Pathology and Laboratory Medicine.
“Toxicity to the blood-forming system is a key limit on drug development, so these cells could be used for safety testing in any drug development,” says Slukvin, who performs research at the National Primate Research Center in Madison.
Bone marrow stem cells are already used to screen drugs, but the new technique promises to produce large quantities of cells in a dish that can be more exactly tailored to the task at hand, without requiring a constant supply of bone marrow cells from donors.
The development of stem cells into mature, specialized cells is governed by trace amounts of biological signaling molecules, so Slukvin and colleagues Kyung-Dal Choi and Maxim Vodyanik exposed two types of highly versatile stem cells to various compounds.
Eventually they found a recipe that would cause the cells to move through a process of progressive specialization into a variety of adult cells. Slukvin’s study was published in the Journal of Clinical Investigation.
Click link above for complete article.
U.S. Stem Cell Research Seems to Focus on Two Lines
From Drugs.com
Only two of 21 approved human embryonic stem cell lines are routinely used by researchers in the United States, says a new study.
The study found that two cell lines, known as H1 and H9, accounted for 941 of 1,217 requests, or 77 percent, placed by scientists since 1999 for human embryonic stem cell lines housed at the two largest stem cell banks in the country.
Another line, H7, was requested 111 times, and 13 other lines were requested fewer than 10 times.
The study’s authors also found that H9 was discussed in 83 percent of 534 published studies from 1999 to 2008, H1 was discussed in 61 percent and H7 in 24 percent. The total is more than 100 percent because many studies used more than one cell line.
“I was surprised by the results,” Christopher Scott, director of Stanford University’s Program on Stem Cells in Society, said in a news release. “I never imagined that we would find that three-fourths of the requests would be for the same two cell lines.”
The study appears in the Aug. 7 issue of Nature Biotechnology.
Scott and his fellow researchers said the findings raise concerns about the reauthorization process of stem cell lines under way at the U.S. National Institutes of Health. If the lines that have been in use are excluded from federal funding because of ethical considerations, they said, scientists might abandon research on them in favor of other cell lines.
However, they added, the two most-used lines might have abnormalities or other characteristics that would make them less useful than newer lines.
Future NIH policies should preserve scientists’ ability to continue work on the well-studied lines while also encouraging the study of ne
Mice created from skin cells
From Cox Newspapers
WEST PALM BEACH, Fla. — Scientists at The Scripps Research Institute in San Diego have created healthy adult mice out of mouse skin cells — no sperm, no egg. Just skin.
The feat, described in the scientific journal Nature this week, was intended to prove that adult cells can be reprogrammed backward in their development, until they have all the desirable characteristics of embryonic stem cells.
According to Gerard McGill, a medical ethicist at Duquesne University’s Center for Healthcare Ethics, this means the ability to treat diabetes, Alzheimer’s, Parkinson’s, hearing loss, or spinal cord damage with a patient’s own cells is within reach.
“It proves that reprogrammed cells are equivalent to embryonic stem cells,” McGill said. “Treatments are at least 15 or 20 years away, but they are reasonable.”
Reprogramming mouse skin cells to grow into complete mice required advances in mouse genetics, genetic engineering, stem cell biology and reproductive technology.
The scientists started using standard fetal mouse skin cells. They then genetically engineered viruses to carry genes for four key proteins believed to be able to reprogram a cell’s behavior. The viruses infected the skin cells, forcing them to produce the compounds.
The scientists hand-selected cells that had the most obvious stem-cell-like traits.
The cells were eventually transferred into fertile female mice.
Two of the embryos survived to become fertile adults.
Replacement teeth grown in mice
Researchers in Japan have successfully grown replacement teeth in mice, according to a report in PNAS journal.
Tissue containing the cells and instructions for building a tooth was transplanted into the jawbones of mice.
They report that these tissue “germs” regularly grew into fully functional teeth with a hardness comparable to that of the natural variety.
The work illustrates a technique that could lead to engineered organ replacements, according to the authors.
They found that nerve fibres were able to grow throughout the teeth and respond to pain stimulation.
The researchers also tracked gene expression in the engineered tooth “germ” with a fluorescent protein.
This revealed that genes that were normally activated in tooth development were also active during growth of the engineered replacement.
The study was led by Etsuko Ikeda from the Tokyo University of Science, Japan.
Stem Cells Primer – Video
From Sciencestage.com
