New Delhi: Environmental exposure to lead can cause Alzheimer’s disease, a recent research done by scientists at Indian Council of Medical Research-National Institute of Nutrition (ICMR-NIN) has established.
Lead, toxic heavy metal, is a common pollutant that can get into environment from a number of commonly used materials like paints, cosmetics, batteries, glass and low grade toys.
Alzheimer’s disease is a progressive and irreversible brain disorder that gradually destroys memory and thinking skills of the person affected. Lead’s role as a risk factor in development of neurodegenerative diseases and many dysfunctions of the human central nervous system is established globally.
The ICMR- NIN team worked on the molecular mechanism involved in the development of lead induced Alzheimer's disease through in vitro (outside a living organism) studies.
“Alzheimer’s disease has a complex patho-physiology (the study of the disordered physiological processes that cause, result from, or are otherwise associated with a disease) which involves initially; formation of beta amyloid plaques (clusters that form in the spaces between the nerve cells) and tangles (knot of the brain cells) in the brain," said Suresh Challa senior scientist at ICMR- NIN who lead the team.
“In addition, oxidative stress and inflammation are known to be involved in the progression of the disease, with loss of memory and neuronal cell death. In this scenario, our study investigated the basic molecular mechanism behind the involvement of lead in Alzheimer’s disease," he said.
The scientists have simulated brain cells in vitro with beta amyloid peptides (amino acids that are crucially involved in Alzheimer's disease) like in Alzheimer’s disease and the effect of Lead exposure was then studied. It showed increased cell death and increased levels of pro-apoptotic marker proteins. Further, the proteins involved in neurodevelopment and regeneration have depleted. Such effects led to decreased expression levels of synaptophysin (a protein), finally leading to loss of memory as in Alzheimer’s disease.
“Maternal exposure to lead during pregnancy can cause developmental reprogramming which can lead to higher risk and early onset of Alzheimer’s disease in later life of the child. Since lead exposure is an important public health concern, the current findings could be another piece in solving the puzzle towards understanding the intracellular mechanism of Alzheimer’s disease. Such findings may as well help in developing preventive and management strategies for elderly", said R Hemalatha, Director, ICMR-NIN.
Further, the scientists also studied therapeutic potential of natural compounds such as catechins, especially, epigallocatechin gallate (EGCG) present in foods like green tea, guava leaves, apples, cherries, pears, black berries which possess antioxidant, anti- inflammatory and metal chelant properties.
Scientists found the ability of these compounds to effectively permeate brain and modify several cell survivals signalling pathways have shown to have preventive and therapeutic potential. The studies have also shown EGCG is protective against lead toxicity and can effectively decrease neuronal cell death by decreasing beta amaloyd peptide accumulation. This can have protective effect in lead induced Alzheimer’s disease, the scientists said.