Some people carry the typical Alzheimer's hallmarks such as amyloid plaques and tau changes in the brain, but remain cognitively healthy into old age. A new systems biology research project has now shown that preserved mitochondrial energy production could be the crucial protective factor.
The study published in the journal “Communications Biology” by Priyanka Baloni and Purba Mandal (Purdue University) analyzed almost 8,000 proteins from brain tissue of individuals with clinical Alzheimer's disease, asymptomatic Alzheimer's pathology (AsymAD), and healthy controls. While mitochondrial metabolic pathways such as the electron transport chain, the TCA cycle, and fatty acid oxidation were strongly downregulated in Alzheimer's patients, these remained largely intact in resilient brains despite comparable amyloid and tau burden.
The researchers compare mitochondria to a car's engine: even with external damage (plaques and tau), a functioning engine can maintain performance. NADH, a central cofactor in energy production, proved to be a particularly important marker for this resilience.
The results suggest that, in addition to removing pathological proteins, strengthening mitochondrial functions – for example, through NAD+ precursors or other interventions – could be a promising complementary therapeutic strategy. The authors emphasize the value of studying asymptomatic cases as a "natural experiment" for understanding brain health.
The study provides a molecular basis for the link between metabolic health, physical activity, and cognitive reserve, opening up new approaches beyond pure pathology reduction.
