AIIMS blood test offers hope & help in early Alzheimer’s diagnosis

A simple blood test, developed by researchers and doctors at the All India Institute of Medical Science (AIIMS), New Delhi, may help in early diagnosis of Alzheimer’s Disease, a progressive type of dementia that mainly affects those aged 65 and above.

For the last four years, researchers have been working with 90 patients from Delhi-NCR, all between 50 and 75, at the memory clinic and geriatric departments of AIIMS to develop a blood screening test for early diagnosis of the disease and help understand what caused their memory to fade. Considering an estimated 8.8 million Indians older than 60 have some form of dementia, a predictive blood test can help sift those with Alzheimer’s and help in better disease management.

Researchers tested the 90 patients — 35 with serious memory lapse, 25 with mild cognitive impairment and 30 healthy people — on six blood markers, the levels of which can indicate an early onset of Alzheimer’s Disease, a condition where clusters of amyloid beta (Aß) and tau proteins in the brain disrupt memory and processing functions. The ratio of these proteins in the blood can help you determine the stage of Alzheimer’s.

Buoyed by these findings, which have been published in Bio-Med Central, a UK medical journal, the researchers have now applied for a grant from the Department of Biotechnology (DBT) for further research on this project. The study was supported by the Indian Council of Medical Research (ICMR) and the Department of Health Research (DHR).

“The research is promising and could change therapy protocols if found to be successful in larger trials with a bigger sample size. India could easily become the dementia capital of the world and the biggest gap in understanding the disease is the lack of a blood screening for biomarkers. We have good cerebrospinal fluid (CSF) biomarkers and imaging tests like PET and MRI as of now. But these can detect the disease only when symptoms have already shown up,” says Dr Vishnu VY, additional professor, Department of Neurology.

The AIIMS blood test can detect these biomarkers at least 10 to 15 years before the disease becomes full blown, enabling doctors to slow down its progress.

“This can be done by treatments that can manage symptoms and a lifestyle correction in mid-adult life, involving diet, exercise and managing existing co-morbidities, if any. The idea is to preserve the patient’s level of function longer,” says Dr Vishnu.

Dr Saroj Kumar, Assistant Professor, Department of Biophysics, who worked with a team of researchers from the neurology and geriatric departments, says, “There is no cure for Alzheimer’s and once detected, one can only provide symptomatic relief. But it develops over 15-20 years. So if we are able to detect signs 10 years before, patients might be able to stop degeneration with a healthier lifestyle,” he says.

The biomarkers test is effective because it can measure biological changes that indicate if a disease is present or a person is at risk of developing a disease. Accumulation of protein fragments known as beta-amyloid and tau are, therefore, good biomarkers of Alzheimer’s.

Dr Kumar says that out of the six markers, two are of Alzheimer’s, two are neuronal and two more relate to brain inflammation. All of these indicate disease progression and its severity. “Amyloid Beta proteins form senile plaques, which interrupt memory, thinking and planning abilities. Tau protein forms neurofibrillary tangles in the brain, which impact neurons. Our study found increased levels of amyloid beta and tau proteins in small extracellular vesicles, which transport proteins, DNA, and lipids across distances, in the blood plasma of Alzheimer’s and mild cognitive impairment patients,” he explains.

Dr Kumar says the team found elevated levels of pro-inflammatory cytokines such as Interleukin 1 Beta (IL-1ß) and Tumor Necrosis Factor Alpha (TNF-a) in the plasma of Alzheimer’s and mild cognitive impaired patients. Pro-inflammatory cytokines generally regulate growth, cell activation and immunity. He further adds that the research examined levels of other markers such as Synaptophysin (Syp) and Glial Fibrillary Acidic Protein (GFAP). “Syp is a protein involved in neuronal transmission and we found it to be low in Alzheimer’s and mild cognitive impairment patients. GFAP is a marker for glial cells, which are responsible for cell to cell messaging. We observed increased levels in plasma of Alzheimer’s and mild cognitive impairment patients.” In fact, GFAP can predict future conversion of mild cognitive impairment to dementia.

Dr Vishnu says the research is at a preliminary stage but his lab is now working on targeted drug delivery for patients of Alzheimer’s. “We are not only developing a better diagnosis but also a targeted drug delivery,” he adds.

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