Hippocampal, Microglial, Morphological, and Amyloid Profiles Following Thiamine Pyrophosphate Treatment in 3xTg-AD Mice.

Alzheimer's disease (AD) is characterized by the accumulation of amyloid-β (Aβ) and chronic neuroinflammation, with microglia playing a central role in its pathogenesis. Alterations in microglial metabolism have been proposed to contribute to AD-related inflammatory responses and reduced Aβ clearance, suggesting that thiamine-dependent pathways may be relevant in this context. Thiamine pyrophosphate (TPP), the active form of vitamin B1, is essential for glucose metabolism and mitochondrial function; however, its association with microglial changes in AD remains unclear. In this study, 9-month-old female triple-transgenic AD (3xTg-AD) mice and non-transgenic controls (NoTg) received TPP (2.0 mg/mL) or saline as a vehicle for six weeks via osmotic pumps. Nesting, a hippocampus-dependent behavioral test, as well analyses of Aβ burden, microglial morphology, and the expression of genes related to metabolic and immune pathways were evaluated. Differences in nesting behavior between experimental groups were observed, but TPP treatment was not associated with an evident change in 3xTg-AD mice. In the subiculum and CA1 regions of the hippocampus of female 3xTg-AD mice exposed to TPP, a lower Aβ burden was observed, and morphological variations in microglia were detected in both groups (3xTg-AD and NoTg). Additionally, in the brain of the TPP-treated group, some changes in mRNA gene expression were recorded. Together, these findings describe hippocampal microglial and amyloid profiles following TPP treatment in 3xTg-AD mice and provide a basis for further investigation of thiamine-dependent pathways in AD-related neuroinflammatory contexts.