哥伦比亚医生发现糖尿病心脏病链接的线索

纽约，NY - 2000年6月15日-一种帮助清除血液脂肪的蛋白质出现异常，这可能是糖尿病患者患心脏病风险大大增加的原因。哥伦比亚大学内外科医学院的尼尔·s·沙克特博士和他的同事在本月的《临床研究杂志》上发表了一项研究。患糖尿病时，一个人的身体不能正常使用糖，要么是因为他或她不能产生胰岛素，要么是无法对这种激素做出反应。与没有糖尿病的人相比，糖尿病患者更有可能患上动脉粥样硬化(动脉硬化)和其他类型的心血管疾病。到目前为止，还没有发现这种风险增加的原因。当一个人摄入脂肪时，必须采取一系列步骤，使这些脂肪到达需要它们的细胞，并使肝脏清除血液中多余的脂肪。不同的蛋白质包装，运输，和透明的脂肪颗粒含有甘油三酯通过身体。这些蛋白质的异常会导致血液中甘油三酯水平升高，这是心脏病的主要风险因素。沙克特博士的研究表明，一种名为硫酸肝素蛋白多糖(HSPGs)的蛋白质的异常可能解释了糖尿病和心脏病之间的联系。沙赫特博士是哥伦比亚大学内科和外科医生学院预防医学和营养和心脏病学部门的医学助理教授。 Dr. Shachter and his colleagues observed the metabolic effects of giving diabetic mice a large amount of fat to eat. “They clear it extremely poorly,” says Dr. Shachter. “This is similar to what we see in diabetic humans.” Then the Columbia researchers conducted a series of experiments to identify why this occurred. The only abnormality in fat metabolism they found was in the animals’ HSPGs. Unlike most proteins, HSPGs contain a large amount of structured sugar chains. These proteins have been shown to be abnormal in diabetic humans, but the consequences of this abnormality had not previously been determined. “This appears to be the mechanism of why diabetics have slowed clearance of dietary fat particles,” says Dr. Shachter. “It sort of connects the dots.” In other experiments, Dr. Shachter and his colleagues examined how HSPGs were formed in cultured cells exposed to high sugar concentrations, mimicking the environment inside a diabetic person’s body. The formation of the proteins takes three steps, and researchers found abnormalities in each of the steps. “At every step of the way, there’s less HSPG being made,” Dr. Shachter explained. The next step for the Columbia team will be to determine why HSPGs are abnormal in people with diabetes. Finding the answer to this question could help researchers develop ways to prevent and treat the complications of diabetes, which include eye and kidney damage as well as heart disease. “All of these major end-stage complications of diabetes have a lot to do with proteoglycan abnormalities,” Dr. Shachter says. “That could give us a direct hook into what diabetes does to you.” Dr. Claude Lenfant, director of the National Heart, Lung, and Blood Institute, which supported the study, said: “The increased atherosclerosis experienced by patients with diabetes is not completely understood. In this intriguing study, there is evidence of a link between the disordered metabolism of glucose found in diabetes and an abnormality in lipid metabolism, together producing an effect in the blood vessel wall likely to promote plaque buildup. If this finding is replicated in humans, it may lead to the development of new targets for drug treatments to control the cardiovascular complications suffered by so many diabetics.” This research was supported by grants from the National Heart, Lung, and Blood Institute and the Juvenile Diabetes Foundation.