Could a simple blood test hold the key to detecting Alzheimer’s disease?

Can a simple blood test combined with a short neuropsychological examination diagnose Alzheimer’s disease? Can taking a daily supplement prevent cognitive decline in patients with early stages of the disease?

A researcher from the sprawling campus of the National Brain Research Center at the foot of the Aravalis is trying to answer these questions using a specialized MRI machine. Unlike those seen in tertiary care hospitals, this one can not only photograph the brain, but also distinguish between the chemicals present in it and the compounds it absorbs. And it helped Dr. Pravat Mandal to discover the relationship between a naturally occurring antioxidant called glutathione and iron levels in our blood and brain. “It’s not like any other MRI machine – we’ve trained it to detect chemical compounds in the brain that have a different frequency. Once we know that frequency, we can focus on it and only that compound will be visible. Using this technique, we were able to measure glutathione levels in the brains of healthy participants and Alzheimer’s patients,” he says.

In addition, this MRI machine can also detect the difference in the texture of brain tissues that have absorbed iron. Why is this important? Doctor Mandal, who is an engineer by training and then worked in the radiology, anesthesiology and psychiatric departments of renowned American institutions, has a hypothesis. He believes that levels of the antioxidant glutathione and iron in critical parts of the brain are predictors of Alzheimer’s disease. “As we live our daily lives, we create free radicals in our brain. Our mood, lifestyle, what we eat and the type of air we breathe all determine the level of free radicals generated. Now the body has a natural mechanism to neutralize these free radicals using the antioxidant glutathione. An imbalance between iron levels – which is a free radical generator – and glutathione levels is probably one of the causes of Alzheimer’s disease,” says Dr Mandal.

His team has already shown a difference in iron and glutathione levels in the hippocampus of healthy individuals and people with Alzheimer’s disease. In fact, his research is among those that challenge the theory of amyloid beta protein deposition as the cause of Alzheimer’s disease. Instead, he considers these deposits to be a symptom of a neurodegenerative disease. “If we liken Alzheimer’s disease to the Ganga River, scientists thought the amyloid beta protein deposition was Gangotri, when in fact they were probably in Kanpur or Haridwar. We still have a ways to go before we reach Gangotri or the origin of the disease,” explains Dr Mandal.

So how does his research lead to the development of a treatment or diagnosis of a disease? With regard to this theory, Dr. Mandal began imaging the brains of healthy subjects while performing blood tests at the same time. The previously unpublished results of this study on 70 healthy subjects helped him determine the baseline levels of iron and glutathione in the brain as well as in the blood in different age groups. Comparing this to the decreasing levels of glutathione and increasing levels of iron in the brains of Alzheimer’s patients may help create a scale for detecting the disease.
“My previous study showed that there is a decrease in glutathione levels and an increase in iron levels in the brains of people with mild cognitive decline and Alzheimer’s disease, in contrast to healthy subjects, but at the time we did not test the blood of these subjects. Now we have data from healthy individuals, and simply trying to do the same in Alzheimer’s patients will help us develop a scale,” said Dr. Mandala. Once this scale is developed, a simple blood test performed in even a basic laboratory setting can predict the disease and, in conjunction with a neuropsychological test, can be used to determine early whether a person has the disease.

Tests to determine a patient’s cognitive function are still performed now to see if a person might have the disease. However, several tests are also needed to eliminate other possibilities of such cognitive decline. This new method may simplify diagnosis. Doctors may sometimes suggest cerebrospinal fluid analysis or brain imaging to detect deposits of amyloid beta protein, a marker of the disease.

With regard to the same principle, Dr. Mandal hypothesizes that taking daily supplements of glutathione—which is already marketed as a nutraceutical—may help prevent slippage in patients with mild cognitive decline. Examination will be conducted with AIIMS.

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