Brain's inability to repair itself may explain dementia

A study focusing on how different parts of the human body repair DNA has found that our brains may not be capable of DNA repair, which may be a root cause of memory loss and dementia.

Researchers from Nova Southeastern University analyzed the process of nucleotide excision repair (NER), a type of DNA repair. NER occurs as a result of cancer-causing agents, such as ultraviolet rays, metals, and oxidative stress. It works by mending areas of the DNA that contain undesirable additional molecules that distort the DNA helix and impede with DNA copying during cell division.

For the study, mouse cell tissues were taken from different organs and tested for their DNA repair ability by being exposed to ultraviolet light. Skin cells were used as a control in the experiment.

The study, published in the journal Photochemistry and Photobiology, found that the heart has the greatest ability to repair DNA using NER, followed by the gut, kidneys, spleen, testes and lungs. But the brain appeared to have no ability to use NER for DNA repair, which may play a part in understanding the cause of dementia and memory loss.

The researchers theorized that since brain cells are not exposed directly to light, they concentrate instead on other essential functions. One scientist also noted that because the human body wasn’t originally designed to last more than 30 or 40 years, the brain has still not yet prioritized DNA repair over other functions.

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