Elevated levels of several HNE-modified proteins of energy metabolism, including alpha-enolase (ENO1), phosphoglycerate kinase 1 (PGK1), pyruvate kinase (PK), mitochondrial ATP synthase α chain (ATP5A), malate dehydrogenase (MDH) and triosephosphate isomerase (TPI), were detected in mild cognitive impairment (MCI) patients associated with a risk for Alzheimer's disease. Here, TPI1 is linked to Alzheimer disease.