Academia Sinica makes key SARS breakthrough

Academia Sinica researchers have made several breakthroughs over the past two years, including producing proof that adult lung stem cells may have played a key role in the SARS epidemic, Academia Sinica President Wong Chi-huey (翁啟惠) said yesterday.

In a report to the legislature's Sci-Tech and Information Committee, Wong said that a team led by John Yu (游正博), head of the Stem Cell Program at the Genomics Research Center, made the discovery about lung stem cells.

Wong the team's study shows that lung stem cells were an important target of the SARS virus in their "decapitation strike" attacks on the lungs.

Yu a lag time between the peak virus load of SARS patients and the development of acute respiratory distress syndrome (ARDS), Wong said, and speculated that the lag time might reflect the duration of a stem cell's regenerative cycle to repair lung damage.

Quoting report by Yu's team, Wong said it has been known that 90 percent of the lung cells contribute to lung tissues as bubbles for gas exchange, referred to "type I pneumocytes" which are derived from "type II pneumocytes."

Scientists long speculated that there are adult stem cells in the lung which are responsible for making both type I & II lung cells in order to maintain the smooth running of the respiratory system. Proof was finally provided by Yu's team in the in vitro study of SARS infected lung tissues, Wong said.

He said the team had grown lung cells in vitro, and they noticed only one unique cell population was infected by the SARS virus. Through various steps of verification, they found that this specific group of cells bears the Oct. 4 and SSEA-1 markers which are also markers for embryonic stem cells. Therefore, it is very likely these cells that are targeted specifically by the SARS virus are the pulmonary stem progenitor cells.

"They could also be the left over `embryonic' stem cells hidden in the lungs," Wong quoted Yu as saying.

The study points to the possible involvement of lung stem cells in SARS-CoV infection, accounting for the continued deterioration of lung tissues and apparent loss of capacity for lung repair in the later stage of infection, Wong said.

The study results were published in the Proceedings of the National Academy of Sciences last year and have opened a door for future manipulation of lung stem cells in cellular therapy of ARDS, Wong said.

A patent application is being processed, he said.

Meanwhile, Wong claimed that Academia Sinica has led other research institutes in the country over the past 10 years in terms of the number research articles or theses cited. Each Academia Sinica article or thesis has been cited an average of 8.39 times over the past decade, compared with 6.25 times for those produced by National Taiwan University, he said.