The effects of prolonged fasting on energy metabolism and mitochondrial functions in Alzheimer’s disease model applied HT22 cells

Mitochondrial dysfunction is recognized as a key factor contributing to neurodegeneration in Alzheimer’s disease (AD). While glucose metabolism is impaired in AD, ketone metabolism remains unaffected. Therefore, ketones may offer a potential therapeutic approach for neurodegenerative diseases with impaired glucose metabolism. This study aims to investigate the metabolic effects of prolonged fasting under pathological conditions and to preserve neuronal function. The pathological Alzheimer’s disease model was simulated in vitro by applying 10 μM Aβ (1-42) to HT22 cells. A fasting model was simulated using EBSS (Earle’s Balanced Salt Solution) medium, and 5 mM beta-hydroxybutyrate (βOHB) was administered. Aβ accumulation in the cells was examined using immunofluorescence techniques and confocal microscopy. Metabolic parameters, including beta-hydroxybutyrate, glucose, lactate, lactate dehydrogenase, and amino acids, were measured from the cell medium and lysates. Mitochondrial function was assessed by measuring citrate synthase enzyme activity. According to results, beta-hydroxybutyrate improved the viability of experimental groups (P < 0.5), while Aβ (1-42) exhibited toxic effects on HT22 cells, which were mitigated by βOHB treatment. Higher citrate synthase activity was observed in both the βOHB-control and βOHB-fasting groups. In groups treated with both Aβ (1-42) and βOHB, enzyme activity was increased compared to groups without βOHB (p < 0.1). Additionally, cells incubated with βOHB utilized both glucose and ketones for energy metabolism, leading to enhanced mitochondrial activity during ketone utilization. These findings suggest that while the addition of ketones can alleviate the damage caused by amyloid-beta, it does not completely restore neuronal function. The results highlight the potential for developing alternative interventions to preserve neuronal function in various neurodegenerative diseases.