Build-up of urea in the brain causes dementia, say scientists

The build-up of urea in the brain has been found to be one of the major causes of dementia, according to scientists. This major breakthrough is the work of an international team of researchers and extends the findings of previous studies.

Scientists from the University of Manchester, the University of Auckland, AgResearch New Zealand, the South Australian Research and Development Institute, Massachusetts General Hospital and Harvard University have all been involved in the research.

It shows that toxic levels of urea can lead to brain damage, which in turn becomes dementia. It builds on the research carried out by Professor Garth Cooper of the University of Manchester, which identified metabolic links between Huntington’s, several neurodegenerative diseases and type-2 diabetes.

Huntington’s disease is one of the seven main types of dementia, but is a hereditary condition. Establishing a link between the illness and urea could have more widespread impact on treatment for related conditions, such as Alzheimer’s, as research continues to push forward.

One of the most pertinent elements of the Huntington’s study was the fact it showed high levels of urea were present before any symptoms of dementia began. This could lead to earlier diagnoses in future, meaning treatments could be administered while they still have a good chance of being effective.

While urea is most commonly thought of as the compound that leaves the body in urine, it is also the result of the metabolic breakdown of proteins. When urea and ammonia are not eliminated from the body efficiently, build-up can occur, which can have serious consequences.

Professor Cooper said: “This study on Huntington’s disease is the final piece of the jigsaw which leads us to conclude that high brain urea plays a pivotal role in dementia. Alzheimer’s and Huntington’s are at opposite ends of the dementia spectrum – so if this holds true for these types, then I believe it is highly likely it will hold true for all the major age-related dementias.

“More research, however, is needed to discover the source of the elevated urea in Huntington’s disease, particularly concerning the potential involvement of ammonia and a systemic metabolic defect.

“This could have profound implications for our fundamental understanding of the molecular basis of dementia, and its treatability, including the potential use of therapies already in use for disorders with systemic urea phenotypes.”

At present, there is no cure for dementia, although scientists around the world are working simultaneously to find one. It is a condition that is only set to become more prevalent over the coming decades as people live longer into old age.

Dementia seriously reduces quality of life, as the irreversible loss of brain cells means that cognitive degeneration is inevitable. Many patients lose their independence as a result and it’s down to relatives to make difficult decisions about the best ways to care for elderly parents.

Breakthroughs, such as this latest one, however, provide hope and could help to reverse the current trend of dementia cases growing exponentially year-on-year. More research is required, but each new finding helps to draw a bigger picture of the condition.