Hyderabad: A new study by scientists at the Indian Council of Medical Research–National Institute of Nutrition (ICMR-NIN) has found that exposure to lead can significantly worsen damage to nerve cells. The damage is observed especially when it occurs alongside amyloid-beta, a protein associated with changes seen in certain brain diseases such as Alzheimer’s.

What the study looked at

The research, published in the Journal of Applied Toxicology, tested lead and two forms of amyloid-beta on human nerve cells in a laboratory setting.

Lead is a heavy metal that people can be exposed to through contaminated water, old paint, certain cosmetics and industrial pollution. Amyloid-beta, meanwhile, is a protein fragment that tends to clump together in the brain and is widely studied for its role in neurodegenerative conditions.

ICMR-NIN scientists found that each of these substances, tested separately, caused some degree of damage to nerve cells.

But when the cells were exposed to lead and amyloid-beta simultaneously, the resulting damage was significantly greater than what either substance produced on its own.

How the damage unfolds

According to the study, this combined exposure reduced the survival of nerve cells and damaged lysosomes—small structures inside cells that act like a recycling and waste-disposal system, breaking down and clearing out unwanted material.

When lysosomes stop functioning properly, waste products can build up inside the cell, disrupting its normal activity.

The study also found that the combined exposure affected proteins and genes that help maintain lysosomal health. Researchers observed that lysosomal membranes became weak and permeable under this dual exposure, which could potentially allow harmful substances to leak out and spread within the cell — a process that may accelerate broader cellular damage.

‘Lead worsens lysosomal dysfunction’

Dr Suresh Challa, an NIN scientist and head of the institute's cell biology division, who led the study, said the findings demonstrate that lead exposure can significantly worsen lysosomal dysfunction in the presence of amyloid-beta.

He explained that understanding these cellular changes could help researchers better explain how environmental exposure affects long-term nerve health, especially in the context of age-related brain conditions.

Why this research matters

NIN Director Dr Bharati Kulkarni said the study highlighted the importance of understanding how environmental pollutants interact with the human body at a cellular level.

She noted that such research could help scientists better understand the biological processes underlying various brain diseases, many of which are still not fully understood.

The bigger picture

Environmental exposure to heavy metals like lead remains a public health concern in many parts of India, given ongoing sources such as contaminated groundwater, industrial emissions and legacy lead in paints and pipes.

Understanding pollutants impact on body

Findings like these add to a growing body of research examining how everyday environmental pollutants might interact with biological processes already underway in the ageing brain, rather than acting in isolation.

While this study was conducted on cells in a laboratory setting and not on living organisms, ICMR-NIN researchers say it adds important groundwork for future studies into how combined environmental and biological factors could influence the risk or progression of neurodegenerative disease.