In a joint study, researchers at Queensland Brain Institute and Havard medical School team found that when a toxic protein builds up, it starves brain cells of energy, causing them to die.
According to ABC online report, in the study of over three years, scientiests tried to unveil the mystery surrounding Alzheimer's disease and a section of the brain cell called the mitochondria, the part responsible for metabolising energy, was analysed.
Perry Bartlett of Queensland Brain Institute said it was the cell's engine room.
"The bigger these mitochondria are, the harder it is for them to move up and down these long processes of nerve cells," he said, adding that "Nerve cells have processes up to a metre long, they go from your brain all the way down."
"So in order for them to be able to transport these mitochondria to the place where the actions happening in the nerve, if they're too big, they won't move," he said.
Bartlett said this is the first study to directly link toxic levels of Tau, a protein in the brain that is related to dementia, to abnormalities in the mitochondria which starves them of energy and destroys brain cells.
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"If they engineer these changed genes into fruit fly or a mouse they find these tangles but they also found these big mitochondria, so then they ask, well is it the size of the mitochondria that's important?" he said.
"And as it turns out yes it is, because if you reduce the size of the mitochondria, that neuropathology, that toxicity goes away," he said.
Researchers claimed that the latest development was a promising step towards developing an effective treatment for sufferers.
"What most people don't realise is dementia is a terminal illness, so you have to get your head around that fact," she said.