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【medical-news】Skin test may help detect early Alzheimer's
Skin test may help detect early Alzheimer's
Medical Research News
Published: Wednesday, 16-Aug-2006
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A simple skin test that would allow detection of Alzheimer's disease appears to be a realistic possibility in the future.
According to scientists at the Blanchette Rockefeller Neurosciences Institute (BRNI), substances in skin cells may provide doctors with a quick and accurate yes-or-no answer when they suspect a patient is showing early signs of the disease.
They say the test could be performed easily by a nurse or medical technician in a doctor's office or outpatient clinic.
The researchers at BRNI have apparently found a biomarker that can accurately distinguish between Alzheimer's disease and other forms of dementia during the first one to two years of the disease's progression.
The biomarker showed high rates of accuracy when it was tested with human skin cells from a tissue bank, as well as for samples obtained in a previous, unpublished study of patients with autopsy-confirmed diagnoses.
The biomarker also has the potential to be used with blood samples.
Dr. Daniel L. Alkon, M.D., scientific director of BRNI and coauthor of the study, along with with Tapan K. Khan, Ph.D., assistant professor, say that in the initial stages Alzheimer's disease is often difficult to distinguish from other dementias or mild cognitive impairment, but treatments for Alzheimer's are most effective before the devastating and widespread impairment of brain function that inevitably develops after four or more years.
Other scientists have found that Alzheimer's effects are found throughout the body and not just in the brain, but the BRNI team has located a biomarker for the disease by testing for signs of Alzheimer's-related inflammation in skin cells called fibroblasts, without the need for invasive tests previously required, such as a lumbar tap.
It seems that when Alzheimer's disease occurs it stimulates a change indicated by a steep imbalance in the ratio of the two forms of the enzyme, MAP kinase Erk, in skin cells that are exposed to bradykinin, an inflammation-related molecule.
That particular imbalance is not seen in cells of people without dementia or those with other forms of dementia, such as Parkinson's disease, multiple infarct dementia and Huntington's chorea.
Drs. Khan and Alkon have created an Alzheimer's Index that may well help doctors' evaluations of dementia, which allows scientists to convert the test results for each patient to a single number.
Alkon says the test produced good results when run on 60 tissue samples: 30 from a tissue bank, and 30 from autopsy samples of people diagnosed with Alzheimer's disease.
An unpublished study of the test performed on 100 people showed equally good results, and the researchers say they are ready to expand this to thousands.
Experts say such expanded testing is essential, as the hypothesis behind the test is by no means an accepted formulation, nor have they proved it.
Though the presence of inflammation around the amyloid clumps that form in the brain of Alzheimer's patients is well known, whether there is inflammation elsewhere in the body has yet to be established.
Alkon says the results demonstrate that when the Alzheimer's Index agrees with the clinical diagnosis of the presence of Alzheimer's, there is a high probability of accurate diagnosis.
翻译：
皮肤测试有助于检测早期阿尔茨海默氏症
在不久的将来，通过一个简单的皮肤测试就能检测出早期阿尔茨海默氏症。据BRNI神经研究所研究员说，当他们怀疑某个患者表现出早期阿尔茨海默氏症状时，皮肤细胞的某些物质可以为我们提供快速精准的答案。他们认为，这个测试易于护士或技师在医生办公室或者门诊简便操作 。
研究员显然找到了一种可以在疾病进程的前一两年里精确区分阿尔茨海默氏症和其他痴呆的生物标记。和之前未经报道的患者尸解确诊以及人类皮肤细胞组织库比较，人类皮肤细胞的这种生物标记显现了高度精准率。此生物标记也可被开发成血液样本。
研究所一同负责的Daneil L.Alkon医学博士以及副教授Tapan K.Khan博士谈到：最初，我们很难区分阿尔茨海默氏症和其他痴呆症，轻度认知障碍，但是，在经过四年或许再多几年而无法避免毁坏大脑认知功能之前，阿尔茨海默氏症的治疗绝大多数是有效的。
另外有研究员发现：阿尔茨海默氏症不仅侵犯大脑，而是累及全身的疾病。而研究所科研组无需腰穿之类的侵入性检测，就可以从皮肤成纤维细胞的老年痴呆症相关炎症分子定位到这种生物标记。
在非痴呆或者那些有其他痴呆表现的疾病，诸如帕金森病，多发性梗塞性痴呆，其患者皮肤细胞中是没有这种局部失衡。
Khan 和Alkon博士创造出一种老年痴呆症指数，它能很好地帮助医生诊断痴呆，研究员就可以将这些检测转换成简单的数字。Alkon说，60个组织样本的监测将得出较好的结果，其中30个来自于组织库，30个来自于明确诊断为阿尔茨海默氏症的尸检样本。一项未公开的测试研究用100个样本同样有很好的结果，研究员说他们已经准备将样本扩大至数千个。专家认为，这种扩大测试是有必要的，而测试之究竟决不会被公开，同样也没有进一步证实这种假设。
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作者:admin@医学,生命科学 2011-01-28 17:14
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