by Anjali Sadarangani
Heart health. Exercise. Inflammation. All of these research areas have been associated with Alzheimer’s disease and claim to lead to the cure for this devastating disease, yet there is still no feasible treatment option for patients. In fact, Alzheimer’s numbers have been continuously increasing. According to the Alzheimer’s Association, currently 5.8 million Americans live with this disease, making it the sixth leading cause of death in the United States. Amidst all the theories about Alzheimer’s, very few researchers have focused on the tiny, yet crucial, organelle: the mitochondrion.
Mitochondria are double-membraned organelles, integral to cell bioenergetics due to their role in ATP, or adenosine triphosphate, energy synthesis and cell metabolism. The inner mitochondrial membrane’s electron transport chains utilize oxygen in reactions that produce ATP. The brain’s 100 billion energy-hungry neurons have researchers turning to PET scans to characterize Alzheimer’s patients’ brains by tracking glucose metabolism and brain functioning.
These PET scans showed reduced oxygen flow in Alzheimer’s patients’ brains, making the role of mitochondrial dysfunction in Alzheimer’s disease more apparent. When elements of electron transport chains malfunction, metabolism is reduced. The reduced production of ATP in neurons can result in starvation and, in many cases, cell death.
Other studies have shown that reactive oxygen species (ROS), byproducts of cellular respiration, have been found to contribute to oxidative damage in Alzheimer’s patients’ frontal and temporal lobe brain regions. Additional work reveals that mitochondrial DNA (mtDNA) in Alzheimer’s patients appear more damaged than mtDNA of control subjects. These elevated levels of damage are partially explained by mtDNA’s heightened susceptibility to damage from ROS. Whether these lesions are accumulated or inherited remains unclear, but mtDNA damage may be an indicator of mitochondrial failure.
Even though there is a lot of uncertainty with the role of mitochondrial dysfunction in Alzheimer’s disease, continued research in this area seems promising. Currently, the leading hypothesis about Alzheimer’s regards the accumulation of amyloid beta plaques, which are toxic clumps of amino acids, due to environmental and inherent risk factors like age. Research data has shown the presence of mitochondrial amyloid beta accumulation in Alzheimer’s patients.
To this date, there have been eleven clinical trials dedicated to exploring the role of mitochondria and its DNA on Alzheimer’s. Data from these trials point to more preventative rather than curative measures in stalling the progression of this disease. There is a silver lining — most of these preventative measures are easy to apply and follow. Even though antioxidant supplements have fallen short in clinical trials, there is a growing body of literature supporting the importance of a healthy diet in maintaining brain health.
Foods rich in vitamins with anti-inflammatory properties such as blueberries, leafy greens, and turmeric are currently some of the top foods recommended to prevent dementia. While conclusive results can’t be made from clinical trial data, foods rich in ketones seem to result in neuroprotective effects due to promotion of brain derived neurotrophic brain factor (BDNF) and number of mitochondria.
Research on the potential role of mitochondrial dysfunction in Alzheimer’s implies that Alzheimer’s is a multifactorial disease, and combating this disease will require a combination of interventions. Increased examination of mitochondrial dysfunction’s role in Alzheimer’s disease will hopefully bring us one step closer to finding a cure.
Facts and Figures. (n.d.). Retrieved from https://www.alz.org/alzheimers-dementia/facts-figures.
Ortiz, J. M. P., & Swerdlow, R. H. (2019, March 6). BPS Publications. Retrieved from https://bpspubs.onlinelibrary.wiley.com/doi/full/10.1111/bph.14585.
Image Reference: Dementia,alzheimer’s,age,puzzle,pieces of the puzzle – free image from needpix.com. (n.d.). Retrieved from https://www.needpix.com/photo/1290398/dementia-alzheimers-age-puzzle-pieces-of-the-puzzle-share-constant-old-human.