Thiamine-dependent enzyme changes in temporal cortex of patients with Alzheimer's disease.

Activities of thiamine-dependent enzymes [pyruvate dehydrogenase (PDHC), alpha-ketoglutarate dehydrogenase (alpha KGDH), and transketolase (TK)] were measured in autopsied samples of temporal cortex from six patients with Alzheimer's disease and from eight age-matched control subjects who were free from neurological or psychiatric diseases. Times from death to freezing of dissected material at -70 degrees C were matched. Significant decreases in PDHC (decreased by 70%; P less than 0.01), alpha KGDH (decreased by 70%; p less than 0.01), and TK (decreased by 52%; P less than 0.01) were observed in brain tissue from patients with Alzheimer's disease. In contrast, activities of glutamate dehydrogenase were within normal limits. These findings suggest a possible role for alterations of brain thiamine metabolism or utilization in Alzheimer's disease.