Colour-coded illustration of a glutathione molecular model with carbon (grey), hydrogen (white), nitrogen (blue), oxygen (red) and sulfur (yellow) atoms.Credit: LAGUNA DESIGN/ Science Photo Library/ Getty Images
Antioxidant glutathione neutralises reactive oxygen species that generate oxidative stress in the brain and elsewhere in the body. Oxidative stress, which increases with age, depletes the levels of glutathione. Neuroscientists at the National Brain Research Centre in Gurgaon, India, have found a negative correlation between glutathione levels and pH value in the brains of people with mild cognitive impairment and Alzheimer’s disease1. When brain glutathione levels dropped, pH values rose in these patients’ brains. The brains of healthy older people in the control group didn’t show this negative correlation.
The correlation offers a way to detect Alzheimer’s disease at an early stage, the researchers say.
The research team, led by Pravat Kumar Mandal, analysed the brain scans of those with mild cognitive impairment and Alzheimer’s disease and compared these with scans from healthy patients.
They found that oxidative stress in the brains reduced glutathione considerably in the hippocampus, the seat of memory. Glutathione levels in the left hippocampus were more sensitive.
In response to stress, the mean pH value in the left hippocampus increased significantly towards alkalinity in Alzheimer’s patients. Oxidative stress also slightly increased the pH value in their right hippocampus.
“Combining the results of both hippocampi allowed us to efficiently distinguish the patients from the healthy older people,” says Mandal.
He adds that they found the same negative correlation in the frontal cortex – the outer layer of the front part of the brain.
