聖米高醫院華裔學者掛帥.糖尿病研究獲重大突破
多倫多聖米高醫院內分泌學和新陳代謝科副教授王慶華，夥拍另一名病理學科教授馬塞爾，率領多大醫學院的研究人員，在研究治療1型糖尿病上有重大突破。聖米高醫院昨日公布，研究人員發現伽馬氨基丁酸(GABA)對患有1型糖尿病的小鼠，能起預防和治療作用，該發現對人類未來能夠防範和治癒此病帶來希望。
聖米高醫院(St. Michael's Hospital)轄下李嘉誠知識研究院(Li Ka Shing Knowledge Institute) 基蘭研究中心(Keenan Research Centre) 的兩名科學家王慶華副教授 (Dr. Qinghua
Wang)及病理學馬塞爾教授(Dr. Gerald Prud'homme)，昨晨召開記者會，簡述由他們率領的研究團隊取得的研究結果。兩人的研究報告，亦將在本周出版的新一期美國國家科學院刊物(Proceedings of the National Academy of Science)發表。
1型糖尿病(Type 1 Diabetes)過往被稱為青少年糖尿病，特點是免疫系統破壞了產生和分泌胰島素(Insulin)的胰腺(Pancreas)中之Beta細胞。這樣一來，身體產生很少的胰島素，或根本沒有。唯一的常規治療1型糖尿病方法就是注射胰島素，但胰島素並不治本，因為它不會阻止或扭轉Beta細胞的損失。
王慶華教授及馬塞爾教授與他們領導的研究小組，早前就針對胰腺Beta細胞生產的伽馬氨基丁酸(GABA)進行研究。結果發現，將伽馬氨基丁酸注入患有1型糖尿病小鼠後，可起預防及甚至扭轉病情的作用。
研究小組認為，伽馬氨基丁酸重要之處，在於它可糾正兩個已知導致小鼠1型糖尿病的原因：(一)伽馬氨基丁酸令胰腺恢復製造生產胰島素的Beta細胞；及(二)伽馬氨基丁酸令免疫系統停止破壞那些Beta細胞。要扭轉此病及防止再發病，就必須做到上述兩情況。到現在為止，世界上一直沒有有效的治療方法，可同時實現該兩個目標情況。
研究創先河
伽馬氨基丁酸早已被熟知為大腦中央神經系統內的一種神經介質，但其在胰臟的角色則不明。聖米高醫院此項創先河研究，率先確定和描述伽馬氨基丁酸對小鼠胰腺Beta細胞生存及功能的規範之重要性。該院是次研究項目，是由加拿大健康研究協會(Canadian Institutes of Health Research)、青少年糖尿病研究基金(Juvenile Diabetes Research Foundation)及加拿大糖尿病協會(Canadian Diabetes Association)提供資助。
世界衛生組織將糖尿病分類為：1型糖尿病、2型糖尿病及妊娠期糖尿病(Gestational Diabetes)。1型糖尿病一般是由於自體免疫系統破壞產生胰島素的Beta細胞導致。2型糖尿病是由於組織細胞的胰島素抵抗，即是細胞不再同胰島素結合，使得進入細胞內部參與生成熱量的葡萄糖減少，留在血液中的葡萄糖增多，Beta細胞功能衰退或其他多種原因引起。妊娠期糖尿病則與2型糖尿病相似，也是源於細胞的胰島素抵抗，不過其胰島素抵抗是由於妊娠期婦女分泌的激素所導致。
2011-06-28 星島日報
http://news.singtao.ca/toronto/2011-06-28/city1309249411d3271755.html
該醫院發布之新聞資料如下:
Chemical produced in pancreas prevented and reversed diabetes in mice
By Leslie Shepherd
A chemical produced by the same cells that make insulin in the pancreas prevented and even reversed Type 1 diabetes in mice, researchers at St. Michael's Hospital have found.
Type 1 diabetes, formerly known as juvenile diabetes, is characterized by the immune system's destruction of the beta cells in the pancreas that make and secrete insulin. As a result, the body makes little or no insulin.
The only conventional treatment for Type 1 diabetes is insulin injection, but insulin is not a cure as it does not prevent or reverse the loss of beta cells.
A team led by Dr. Qinghua Wang, in the division of endocrinology and metabolism, and Dr. Gerald Prud’homme, in the division of pathology, has studied the role of GABA, or gamma-aminobutyric acid, an amino acid produced by beta cells in the pancreas. The research was funded by the Canadian Institutes of Health Research, the Juvenile Diabetes Research Foundation and the Canadian Diabetes Association.
The researchers found that GABA injections not only prevented diabetes in mice, but even reversed the disease. Their findings were published today in the journal Proceedings of the National Academy of Sciences.
The significance of GABA is that it corrects both known causes of Type 1 diabetes in mice: It works in the pancreas to regenerate insulin-producing beta cells and it acts on the immune system to stop the destruction of those cells. Those two actions are necessary to reverse the disease and prevent its recurrence. Until now, there has been no effective treatment that achieves both goals at the same time.
GABA has been known for decades to be a key neurotransmitter in the brain, a chemical that nerve cells use to communicate with each other, but its role in the pancreas was unknown. The St. Michael’s study is the first to identify and describe GABA's importance in regulating the survival and function of pancreatic beta cells in mice.
GABA and related therapies will have to be tested in human clinical trials before they can be considered as a new treatment for Type 1 diabetes, said Dr. Wang.
“GABA is the first agent to act both by protecting the insulin-producing cells from damage and by decreasing the body's immune reaction against these cells,” said Dr. Gary F. Lewis, incoming director of the Banting and Best Diabetes Centre and Director of the Division of Endocrinology and Metabolism at the University of Toronto, where insulin was discovered 90 years ago.
“The body's immune reaction against its own insulin-producing cells is responsible for most of the damage that leads to the development of type 1 diabetes. This exciting observation may open up new avenues for the prevention and treatment of Type 1 diabetes in humans.”
Drs. Wang and Prud’homme are both clinician scientists in the Keenan Research Centre of the Li Ka Shing Knowledge Institute of St. Michael’s Hospital. In addition, Dr. Wang is an associate professor in the Department of Physiology at the University of Toronto and Dr. Prud’homme is a professor in the university’s Department of Laboratory Medicine and Pathobiology.
“Diabetes research such as this brings us closer to a cure,” said Michael Cloutier, president and CEO at the Canadian Diabetes Association. “We are excited to be a part of this significant discovery and look forward to the outcomes of clinical studies.”
http://www.stmichaelshospital.com/media/detail.php?source=hospital_news/2011/20110627a_hn
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