Tinny channels found in human's embryonic stem cells will make the cells safer for clinic use, mostly providing cells for transplantation, the University of Hong Kong announced Saturday.

Scientists of the university have discovered "for the first time the presence of functional ion channels in human embryonic stem cells (ESCs)," said a statement on the university's official website updated on Saturday.

ESCs is the only type of human stem cells capable of becoming all human cell types, including those highly specialized cells such as brain and heart cells that can't regenerate.

The unique character of ESCs has offered an alternative solution to limited donor availability and solved the problem of rejection in human transplantation.

One concern of the ESCs-based cell therapies, however, is the potential for engineered grafts to form tumors after transplantation, due to contamination by only a few undifferentiated human ESCs.

Despite of the genetic abnormalities carried by carcinoma cells, some of them can become differentiated into other cell types.

Discovery of the ion channels, valves in a cell's outer membrane that allow and control the passage of charged atoms, has given hope to cut down possibility of tumor formation in ESCs therapies, claimed the Hong Kong scientists.

Since electrical activity is known to regulate cell differentiation and proliferation, scientists may eliminate tumor genic potential by selectively blocking, pharmacological or genetically, ion channels in implanted cells.

The discovery will allow scientists a better understanding of how human ESCs regulate their cell division and differentiation, which is critical for engineering healthy grafts.

Scientists also expect the discovery to lead to genetic strategies that suppress undesirable cell division after transplantation, for they found blocking potassium channels in ESCs slowed their growth.

The research results have been published on the latest issue of an international journal named Stem Cells and related information published on the university's website: www.hku.hk/facmed/press.

(Xinhua News Agency December 5, 2005)