AD	Alzheimer’s disease
BBB	Blood–brain barrier
BDNF	brain-derived neurotrophic factor
cAMP	cyclic adenosine monophosphate
CNS	central nervous system
CREB	cAMP-response element-binding protein
CTSB	cathepsin B
EPO	erythropoietin
FGF21	fibroblast growth factor 21
FNDC5	fibronectin type III domain-containing Protein 5
HKyn	hydroxykynurenine
HPA	hypothalamic-pituitary-adrenal
IGF-1	insulin-like growth factor 1
KATs	kynurenine aminotransferases
KPM	kynurenine pathway metabolism
Kyn	kynurenine
LPS	lipopolysaccharide
MCTs	monocarboxylate transporters
PD	Parkinson’s disease
PGC1α	peroxisome proliferator-activated receptor gamma coactivator 1-alpha
PKA	protein kinase A
QuinA	quinolinic acid
SCFAs	short chain fatty acids
Ser	serotonin
SIRT1	sirtuin 1
Tph	Tryptophane
TrkB	tropomyosin receptor kinase B
VEGF	vascular endothelial growth factor
VN	vagus nerve
β-HB	β-hydroxybutyrate