Alzheimer’s disease: label-free fluorescence shows increases in indoleamine 2,3-dioxygenase (IDO) or tryptophan 2,3-dioxygenase (TDO) activity in affected areas of the brain

摘要

Abnormal tryptophan metabolism is a major factor in Alzheimer’s disease. Thus, understanding the role of indoleamine2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO), enzymes that causes increased tryptophan metabolismdown the kynurenine pathway, is crucial. Tissue samples from the hippocampus, Brodmann’s area 9 (BA 9) andBrodmann’s area 17 (BA 17) from Alzheimer’s patients, from patients with psychosis and from age-matched, normalcontrols (total of 47 samples) were studied. An update on the optical properties of Alzheimer’s tissues, utilizingtryptophan/kynurenine ratios, is reported. Ratios of tryptophan/kynurenine were decreased in the hippocampus and BA 9in patients with Alzheimer’s, consistent with increased neuroinflammation and IDO and/or TDO activity in these areas.