👤 Paul J Kueck

Impaired cerebral glucose metabolism is a hallmark of Alzheimer's disease (AD). Lactate is an alternative brain fuel; however, whole-body lactate metabolism has not been measured in AD. The Lactate for Energy and Neurocognition Trial (NCT05207397) was a single-arm trial that enrolled 24 cognitively healthy (CH) older adults and 12 cognitively impaired (CI) participants. Subjects underwent a stable isotope lactate infusion to evaluate lactate metabolism, cognitive testing, and blood biomarker analyses. pTau217, brain-derived tau (BD-tau), pTau181, glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), total tau, and brain-derived neurotrophic factor (BDNF) were analyzed by Simoa HD-X (Quanterix). Lactate metabolic clearance rate did not differ between CH and CI subjects (p = 0.988). After infusion, global cognition was improved (p < 0.001) and plasma pTau217 (-33.8%, p < 0.001), BD-tau (-32.6%, p < 0.001), pTau181 (-21.4%, p < 0.001), GFAP (-39.7%, p < 0.001), and NfL (-19.5%, p < 0.001) were reduced. Lactate turnover was not different between diagnosis groups. Lactate infusion improved cognition and reduced AD fluid biomarkers. Individuals with Alzheimer's disease (AD) can metabolize lactate as well as healthy controls. Lactate infusion might improve global cognition and processing speed. Lactate infusion results in significant decrease of AD fluid biomarkers. Show less

Alzheimer's disease (AD) pathology is complex and involves mitochondrial dysfunction. There are emerging therapies targeting mitochondrial function in clinical trials for AD. This highlights the need for biomarkers that measure mitochondrial function. We determined the utility of a novel blood-based mitochondrial biomarker, the mitochondrial functional index (MFI), in the context of AD in a pilot study. In vitro and in vivo models of AD had a reduced MFI. MFI was lower in human AD subjects and APOE 𝜀4 carriers. Receiver operating characteristic analysis showed MFI had a higher area under the curve than other plasma biomarkers. The MFI biomarker correlated with the Mini-Mental State Examination (MMSE) and the Clinical Dementia Rating (CDR) scale. This study highlights the potential utility of MFI as a functional blood-based mitochondrial biomarker to interrogate energy metabolism. Ongoing studies are examining the relationship of MFI with brain energy metabolism outcomes. The MFI biomarker is reduced in cell and animal models of AD. The MFI biomarker is reduced in human AD subjects and APOE ε4 carriers. The MFI biomarker can discriminate between subjects with normal cognition and AD with better performance than other plasma biomarkers. The MFI biomarker correlates with cognitive scores. Show less