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脂肪过剩如何引发疾病?

更新时间:2013-12-4 14:31:14 来源:华尔街日报中文网 作者:佚名

Researchers Explore Ways Fat Can Lead To Disease
脂肪过剩如何引发疾病?

Why are some obese people healthy, apparently protected from the damaging effects of excess fat on the liver and other organs?

为什么有些肥胖人士身体健康、显然没有受到过量脂肪对肝和其他器官的危害性影响呢?

Scientists are investigating this question as they look to understand how obesity disrupts normal organ function and causes inflammation, insulin resistance, diabetes and other metabolic abnormalities.

在寻求了解肥胖如何扰乱正常器官机能并引发炎症、胰岛素耐受性、糖尿病和其他代谢异常现象的过程中,科学家们对这一问题展开了研究。

Understanding the different ways in which fat tissue causes disease throughout the body could yield new insights for treatment. Research on the subject was presented in Atlanta last week at Obesity Week, a major conference of weight-loss surgeons and other health professionals.

了解脂肪组织在整个身体引发疾病的不同方式可能会给治疗带来新见解。研究人员在前不久于亚特兰大举行的Obesity Week会议上提交了关于该课题的研究,这是一个有众多减肥外科医生和其他医疗专业人士参与的大型会议。

Much of the new research centers on how some fat tissue becomes unable to do its job of storing new fat cells and instead shunts them off to be stored in places where they don't belong, like liver and muscle tissue.

新研究主要关注脂肪组织如何变得无法发挥储存新脂肪细胞的功能,转而把它们分流到不属于它们的地方(比如肝和肌肉组织)储存起来。

Another line of inquiry examines how different types of fat in the body exhibit different behaviors, with some serving a more useful function than others. Other work has examined the role of viruses and gut bacteria in contributing to body weight and disease.

另一研究领域则探索了身体中不同类型的脂肪是如何展现出不同表现的,比如有些类型的脂肪能比其他类型发挥更有用的功能。其他研究还调查了病毒和肠道细菌在引发体重增加和疾病方面的角色。

Some of the most recent research, conducted by Evan Nadler, co-director of the Obesity Institute at Children's National Medical Center in Washington, D.C., suggests yet a new mechanism for how obesity causes disease all over the body: Small sacs, called exosomes, are produced by fat cells and sent off carrying disruptive disease-causing signals to organs.

在这些最新研究中,华盛顿特区国家儿童医疗中心肥胖问题研究所(Obesity Institute at Children's National Medical Center)联席主任埃文·纳德勒(Evan Nadler)的研究表明了肥胖在整个身体中引发疾病的新机理:脂肪细胞会产生被称为“外切体”的小囊泡,而后这些携带造成扰乱、可引发疾病的信号的囊泡会被输送到器官中。

Though the negative health effects of obesity are well known, scientists have observed that not all obese individuals are unhealthy. Experts at the Atlanta conference said an estimated 10% to 30% of the obese population appears immune to the negative health effects of excess fat and remains metabolically normal-- meaning without inflammation, diabetes or any hint of insulin resistance. For instance, while more than 60% of U.S. adults are overweight or obese, only about 10% are diabetic.

肥胖对健康的负面影响众人皆知,但科学家也注意到并非所有肥胖之人都不健康。参加Obesity Week会议的专家称,据估计有10%至30%的肥胖人群的健康状况似乎不受过量脂肪的负面影响,代谢依然正常,这表明他们没有炎症和糖尿病,也没有出现胰岛素耐受的迹象。例如,虽然美国60%以上的成年人体重超重或肥胖,但只有10%左右的人患有糖尿病。

In the laboratory, scientists including Philip Schauer, professor of surgery at the Cleveland Clinic, have genetically engineered mice that become obese but metabolically remain perfectly healthy. Obese mice typically exhibit insulin resistance.

克利夫兰医院(Cleveland Clinic)外科教授菲利普·肖尔(Philip Schauer)连同其他科学家在实验室展开了研究,他们对老鼠进行了基因改造,后来这些老鼠变肥胖,但代谢依然非常正常。肥胖的老鼠通常会表现出胰岛素耐受性。

What's more, scientists say that for obese individuals who are metabolically normal, health doesn't improve significantly with weight loss.

此外,科学家们称,代谢正常的肥胖人士,就算体重减轻,他们的健康状况也不会大幅改善。

Samuel Klein, director of the Center for Human Nutrition at the Washington University School of Medicine in St. Louis, recently conducted a randomized controlled study in which researchers asked 22 obese individuals to eat more calories, inducing a 6% weight gain.

华盛顿大学路易斯分校医学院(Washington University School of Medicine in St. Louis)人类营养研究中心(Center for Human Nutrition)主任塞缪尔·克莱因(Samuel Klein)最近进行了一项随机对照研究。在该研究中,研究人员要求22名肥胖人士摄入更多热量,导致他们的体重增长了6%。

The subjects who were metabolically normal at the start didn't show any ill effects from the weight gain. But those who started out metabolically abnormal experienced worsened insulin sensitivity after the weight gain. When participants were then induced to lose the weight, only the health of the metabolically abnormal group improved.

一开始代谢就正常的受试者从体重增加时起未表现出任何不良影响,而一开始代谢异常的受试者在体重上升后胰岛素敏感性加剧。后来在按要求减轻体重时,只有代谢异常那一组的受试者的健康状况有所改善。

'A critical question is, Why are some people predisposed to the metabolic dysfunction and others resistant to it?' Dr. Klein says.

克莱因指出:“一个关键问题是,为什么有些人容易代谢失常而其他人则不受影响?”

The answer is a work in progress. The type of excess fat, as well as the amount and the location of it, plays an important role. Belly fat, or visceral fat, which sits around the organs in the abdomen, is considered particularly unhealthy because it doesn't help store new fat cells. Instead, it redirects the cells to other organs for storage, most notably to the liver, and produces damaging inflammatory proteins that can even reach the brain.

对这个问题的解答还在探索之中。过量脂肪的类型、数量及其分布位置都起着重要作用。位于腹部各器官周围的腹部脂肪或内脏脂肪被认为特别不健康,因为它不会有助于贮存新脂肪细胞。反之,它还会将这些细胞引导至其他器官中(最突出的就是肝)储存,并产生甚至还会到达脑部的有害的炎性蛋白质。

Fat cells sitting under the skin's surface, known as subcutaneous fat-- particularly in the thighs, legs and lower body-- 'suck up energy, store it avidly and protect the liver,' says Steven R. Smith, a professor at Sanford Burnham Medical Research Institute in Orlando, Fla. Dr. Smith and his group are studying the molecular programming of lower-body fat in an effort to change other types of fat into this subcutaneous fat.

佛罗里达奥兰多桑福德-伯纳姆医学研究所(Sanford Burnham Medical Research Institute)的教授史蒂文·R.·史密斯(Steven R. Smith)指出,位于皮肤表面下的脂肪细胞(即皮下脂肪),特别是大腿、小腿和下身的脂肪,“可吸收能量,热切地把它储存起来,能保护肝脏。”史密斯及其研究小组正在研究下身脂肪的分子编程,希望藉此将其他类型的脂肪转变为这种皮下脂肪。

Both visceral and subcutaneous fat are made of white adipose tissue and are thought to be less healthy than the type of fat known as brown fat. Brown fat has a darker appearance because the tissue is metabolically active-- which means it burns energy and calories, in contrast with white fat, which just sits.

内脏脂肪与皮下脂肪均由白色的脂肪组织构成,被认为比被人称为棕色脂肪的那类脂肪更不健康。棕色脂肪的外观颜色更深,因为它代谢活跃,这表示它消耗了能量和热量,而白色脂肪只是静止不动。

Scientists have been trying for years to figure out how to create more brown fat. Recently, researchers at Harvard University discovered that with exercise, something called the 'beiging' of fat can occur. Subcutaneous white fat becomes more metabolically active, according to work presented in Atlanta by Bruce Spiegelman, a professor of cell biology at Harvard.

多年以来,科学家们一直在努力弄清楚如何创造更多棕色脂肪。前不久,哈佛大学(Harvard University)的研究人员发现,通过运动,脂肪会出现“变棕”的变化。哈佛大学细胞生物学教授布鲁斯·施皮格尔曼(Bruce Spiegelman)在亚特兰大提交的论文指出,皮下白色脂肪的代谢会变得更活跃。

Another line of study examined how individuals infected with a virus called adenovirus Ad36 not only gain weight but also become more resistant to diabetes, apparently because it causes the redistribution of fat. Instead of being stored in the liver, fat is stored in subcutaneous tissue. 'The fat gets stored in the right place,' says Nikhil Dhurandhar, professor in health promotion at Pennington Biomedical Research Center in Baton Rouge, La., whose group has studied the virus for years.

另一研究领域则探讨了感染了Ad36腺病毒的人不仅体重增加,而且也更不易患糖尿病的问题。这显然是因为它会造成脂肪的重新分布,脂肪不再被储存在肝脏中,而是被储存在皮下组织中。路易斯安那州巴吞鲁日(Baton Rouge)彭宁顿生物医学研究中心(Pennington Biomedical Research Center)的健康促进学教授尼基尔·杜伦德哈(Nikhil Dhurandhar)说:“脂肪储存在了正确的地方。”杜伦德哈的研究小组研究该病毒已有多年时间。

The infected individuals' fat cells increase production of a hormone called adiponectin, known to help increase insulin sensitivity, a protective factor against developing diabetes. 'We want to harness the ability of the virus so we can use it to treat diabetes,' Dr. Dhurandhar says.

感染该病毒的人的脂肪细胞会生成更多的一种被称为脂联素的激素,它有助于提高胰岛素敏感性,这是防止患上糖尿病的保护因素。杜伦德哈说:“我们希望掌握该病毒的功能,这样我们就能利用它来治疗糖尿病。”

While infecting people with the actual virus is out of the question, Dr. Dhurandhar's group recently identified a gene that appears to be responsible for the virus's antidiabetic effect and found a way to deliver the gene into animals. In preliminary work, the researchers injected various doses of the gene into obese mice, which were fed a high-fat diet to impair blood-sugar control.

让人类真正感染上病毒当然不可行,但杜伦德哈的研究小组最近识别出了一种似乎是该病毒防糖尿病效果“功臣”的基因,并找到了一个将该基因注入动物体内的方法。在初步的研究中,研究人员向肥胖老鼠注入了不同剂量的基因,这些老鼠被喂养了高脂肪食品以损害它们的血糖控制机能。

Each exhibited a temporary improvement of one to two weeks in its ability to regulate blood sugar without dieting, though the effect seemed to shorten as the mice aged, according to Vijay Hegde, a Pennington researcher who presented the research at Obesity Week.

彭宁顿生物医学研究中心的研究者维贾伊·赫格德(Vijay Hegde)在Obesity Week会议上提交了这项研究。他指出,在没有节食的情况下,每只老鼠都表现出了一至两周血糖控制能力暂时提高的时期,尽管功效期似乎会随着老鼠年龄的增长而缩短。

The newest but least-studied factor in how obesity causes disease are exosomes, sacs that have been implicated in contributing to cancer because they contain bad-acting DNA modifiers that become incorporated into the cells of other organs. Independent experts say exosomes could be important, but urge caution in interpreting the findings in obesity.

在有关肥胖如何引发疾病的研究中,最新但研究得最少的因素是外切体,此类囊泡被暗指是癌症诱因之一,因为它们含有会被融合到其他器官细胞中的影响不良的DNA修饰基因。独立专家称,外切体可能是重要因素,但他们认为在解释肥胖问题研究中的发现时要谨慎。

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