HAS the cause of brain degeneration been hiding in plain sight? More than 40 years ago, scientists noticed differences in the mitochondria of people with Alzheimer鈥檚 disease. These cellular power stations, which pump out the energy necessary for normal cognitive function, were less abundant in the brains of people with Alzheimer鈥檚, and those mitochondria that remained appeared to be misshapen.
Despite these intriguing findings, scientists remained focused on the now infamous amyloid theory of Alzheimer鈥檚, in which cellular debris called plaques and tangles were thought to underlie the condition. However, decades of failed trials have sent researchers back to the drawing board 鈥� where mitochondria have been given another chance at centre stage.
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And what a performance they are giving. A wealth of new evidence suggests that mitochondrial problems may indeed be the root cause of not only Alzheimer鈥檚, but many other conditions, including 笔补谤办颈苍蝉辞苍鈥檚, Huntington鈥檚 and Lou Gehrig鈥檚 disease (see 鈥淩estoring the brain鈥檚 mitochondria could slow ageing and end dementia鈥�).
It seems an energy crisis in the brain, caused by malfunctioning mitochondria, prevents the growth and maintenance of brain cells and contributes to a build-up of toxic byproducts that exacerbate the cells鈥� bad health and play a part in their untimely death.
Of course, the billions of dollars poured into those failed amyloid trials should highlight the need for caution when it comes to any 鈥済rand unifying theory鈥� of brain disease. But this idea does have some tantalising advantages. Many strands of research support it, including brain imaging, cellular experiments and long-term studies. It also provides an elegant explanation as to why so many genetic and environmental factors can amplify your risk of brain decay, since they all contribute to energy dysfunction.
After decades of dead ends, any new avenue of exploration that brings hope to people with these devastating conditions is worth some (cautious) excitement, and we will be eagerly following its progress.
