Kynurenines with Neuroactive and Redox Properties: Relevance to Aging and Brain Diseases

Table 4

Alterations in kynurenines levels in neurodegenerative diseases.

Disease	Metabolite	Sample	Reference
Alzheimer disease	(i) ↑ TRP/KYN ratio	Plasma	[249]
	(ii) ↑ KYNA levels and KAT I activity	Putamen and caudate nucleus	[192]
	(iii) ↓ KYNA levels	CSF and plasma	[250, 251]
	(iv) ↑ 3-HK	Serum	[252]
Huntington disease	(i) ↑KYNA and 3-HK levels	Neostriatum and cortex in early-stage HD patients	[253]
	(ii) ↓ 3-HK and 3-HA		[254]
Parkinson disease	(i) ↓ KYNA	Frontal cortex, putamen,; and SNpc of patients with PD, CFS	[255, 256]
	(ii) ↑ 3-HK
Schizophrenia	(i) ↓ KMO and 3-HAO	Prefrontal cortex	[257, 258]
	(ii) ↑ L-KYN and KYNA
Depression	(i) ↓ TRP	Plasma	[259–262]
	(ii) ↑ KYN
	(iii) ↑ IDO