Alzheimer's Disease In Old Age Blamed [on Childhood Lead]

2023 Author: Abraham Higgins | [email protected]. Last modified: 2023-11-27 23:16

Alzheimer's disease in old age blamed [on childhood lead]

The origins of Alzheimer's disease and other neurodegenerative diseases in old age may lie in early childhood and be associated with high levels of lead in the child's environment. This is the assumption made by toxicologists at the University of Rhode Island, who studied the effects of lead exposure in infancy on the brain of rhesus monkeys.

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The origins of Alzheimer's and other neurodegenerative diseases in old age may lie in early childhood and be associated with high levels of lead in the child's environment. This is the assumption made by toxicologists at the University of Rhode Island, who studied the effects of lead exposure in infancy on the brain of rhesus monkeys. The research results are published in the December issue of the journal NeuroToxicology.

Lead, present in paint, car exhaust, water and soil, is known to damage the heart, intestines, kidneys and nervous system, even in small quantities, and this substance has a particularly harmful effect on children, limiting the development of the brain and reducing intellectual level. However, the relationship between early lead exposure and the development of dementia in old age has been poorly understood.

A group led by Nasser Zawia, back in 2008, found a correlation between the presence of lead in infancy and the appearance of amyloid-beta protein accumulations characteristic of Alzheimer's in old brain tissue. Then Zawia and his colleagues compared brain tissue samples from five 23-year-olds, who had already died by that time, laboratory rhesus monkeys who received milk formula with a high content of lead in infancy, and four animals of the same age who ate mother's milk in childhood. Macaques have been selected for research because of the similarity of their brain physiology to that of humans.

This time, the researchers examined brain tissue samples from macaques that had been fed milk with lead in childhood, to identify another structural change characteristic of Alzheimer's disease - neurofibrillary tau-protein tangles that destroy the neuron's transport system. It was found that in "lead" monkeys the level of the presence of accumulations of abnormal tau protein in cells of the frontal lobe of the brain is three times higher than in normal animals. In addition, a number of molecular changes have been found that lead to excessive phosphorylation of tau and the formation of its neurofibrillary tangles.

This suggests that exposure to lead at an early age is an epigenetic risk factor for the development of neurodegenerative diseases in the future, influencing the levels of expression of genes and proteins encoded by them through reprogramming of messenger RNA, the authors believe.

As noted by Zawia, quoted by the journal Science, current restrictions on lead use in the United States may help prevent long-term negative effects on the nervous system, but children in other countries where lead continues to be actively present in the environment, such as peeling paint from the walls are at risk.