Neural stem cells grown from one of the federally approved human embryonic stem cell lines proved to be inferior to neural stem cells derived from fetal tissue donated for research, a UCLA study has found.
Researchers from the Institute for Stem Cell Biology and Medicine at UCLA coaxed cells from the federally approved line to differentiate into neural stem cells, a process that might one day be used to grow replacement cells to treat such debilitating diseases as Parkinson's and Alzheimer's. However, the neural stem cells expressed a lower level of a metabolic gene called CPT 1A, a condition that causes hypoglycemia in humans.
The study may shed new light on better ways to grow neural and other stem cells in the lab so they mirror normal cells and promote normal functioning, said Guoping Fan, an assistant professor of human genetics and a researcher in UCLA's stem cell institute. The study appears this week in an early online edition of the journal Human Molecular Genetics.
"This study is a very important first step in looking at the differentiation process in neural stem cells," said Fan, senior author of the study. "Now we have a direct measurement of the types of cells that eventually, we hope, will be used for transplantation. We can tell, are they normal or not. Understanding why these cells under-expressed CPT 1A is the first step in a comprehensive understanding of cells obtained from human embryonic stem cells."
The study, Fan said, deals with one of the most important aspects in stem cell biology - potential abnormalities in cells derived from human embryonic stem cells. Stem cells with abnormalities may not effectively treat the diseases they were created to treat, or they may result in secondary problems such as hypoglycemia, Fan said.
UCLA researchers also compared the neural stem cells they grew to cancer cells to ensure that the neural stem cells did not have any abnormalities in a DNA modification associated with gene silencing. The abnormal DNA modification is characteristically a hallmark of cancer cells. The good news, Fan said, is that the neural stem cells in their study did not share any abnormal characteristics associated with cancer. The means, theoretically, that a patient undergoing transplantation with these neural stem cells would not later develop a malignancy.
In the three-year study, researchers compared the neural stem cells grown in the lab from human embryonic stem cells to neural stem cells that already had differentiated and were derived from donated fetal tissue. The question: would the cell lines be the same and mirror the normal neural stem cells found in humans or would one cell line be superior to the other?