Sun, Jun 27, 2004 - Page 2 News List

Local scientists achieve stem cell breakthrough

STUDY Doctors have developed a new approach to cultivating stem cells which they say frees researchers of the ethical problems associated with previous methods


Amniotic fluid extracted for routine genetic tests performed during pregnancy could be used for stem cell research and tissue engineering, according to a study conducted by local doctors.

"We found a way to isolate mesenchymal stem cells [MSCs] from amniotic fluid routinely extracted during the second-trimester amniocentesis by implementing a two-stage culture protocol," said Tsai Ming-sing (蔡明松), a doctor at the Prenatal Diagnosis Center of the Cathay General Hospital's department of obstetrics and gynecology.

According to Tsai, stem cells, which are capable of replicating into different kinds of tissues, including bone, cartilage, fat, tendon, muscle and even neuron-like cells, are most commonly extracted from adult bone marrow and embryonic tissues or organs.

These stem cells could possibly be used to treat heart disease, diabetes, stroke and spinal and head injuries, among other uses.

"MSCs could be used to repair many injuries and diseases. Neurological injuries, head injuries, Alzheimer's, Parkinson's -- treatment for these conditions will be the focus of future research plans," Tsai told the Taipei Times yesterday.

Given Tsai's latest findings, women receiving second-trimester amniocentesis, a procedure during which a sample of the fluid surrounding a fetus is extracted for the purpose of identifying genetic mutations and characteristics such as sex, could be the key to collecting MSCs.

"We've found a way to cultivate the MSCs from the amniotic fluid without interfering with the routine process of fetal karyotyping," Tsai said.

Karyotyping is a commonly used technique used to study the appearance of chromosomes during genetic diagnosis.

Tsai yesterday explained the advantages that his research findings had over other methods of harvesting and cultivating MSCs.

"Because the extraction of MSCs from prenatal tissues and organs often lead to abortion, embryonic stem cell research faces many difficult ethical problems. However, MSCs derived from amniotic fluid are free of these ethical questions," Tsai said.

He said that extracting the cells from amniotic fluid bypasses the problems associated with a technique called donor-recipient HLA matching, which involves trans-planting bone-marrow stem cells.

"This opens a new avenue for ... fetal gene and cellular therapies without inducing tissue rejection," Tsai writes in an article published in this month's edition of the medical journal Human Reproduction. The journal features a picture of MSCs studied in Tsai's project on its cover.

While current technology allows scientists to collect amniotic fluid through the cervix, Tsai said that this could lead to the possible premature termination of pregnancy and contamination by the mother's blood.

According to Tsai, a significantly larger amniotic fluid culture could be collected utilizing second-trimester amniocentesis.

"With amniotic fluid cells, it takes 20 to 24 hours to double the number of cells collected. The doubling time for [umbilical] cord stem cell is 28 to 30 hours. Bone marrow takes over 30 hours. With urgent medical conditions, speed could be crucial," Tsai said.

In addition, while scientists have only been able to isolate and differentiate on average just 30 percent of MSCs extracted from a child's umbilical cord shortly after birth, the success rate for amniotic fluid-derived MSCs is close to 100 percent, according to Tsai.

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