title: Cognitive deficit in amyloid-beta-injected mice was improved by pretreatment with a low dose of telmisartan partly because of peroxisome proliferator-activated receptor-gamma activation.
abstract: The pathological hallmark of Alzheimer disease is deposition of amyloid-beta protein (Abeta) in the brain. Telmisartan is a unique angiotensin II receptor blocker with peroxisome proliferator-activated receptor-gamma (PPAR-gamma)-stimulating activity. Activation of PPAR-gamma is expected to prevent inflammation and Abeta accumulation in the brain. We investigated the possible preventive effect of telmisartan on cognitive decline in an Alzheimer disease mouse model via PPAR-gamma activation. Here, male ddY mice underwent ICV injection of Abeta 1-40. Cognitive function was evaluated by the Morris water maze test. A low dose of telmisartan (0.35 mg/kg per day) was administered in drinking water with or without GW9662, a PPAR-gamma antagonist. Cerebral blood flow was evaluated by laser speckle flowmetry. Inflammatory cytokine levels were measured by quantitative RT-PCR. Abeta 1-40 ICV injection significantly impaired cognitive function. Pretreatment with telmisartan improved this cognitive decline to a similar level to that in control mice. Cotreatment with GW9662, a PPAR-gamma antagonist, attenuated this telmisartan-mediated improvement of cognition. Treatment with telmisartan enhanced cerebral blood flow and attenuated the Abeta-induced increase in expression of cytokines, such as tumor necrosis factor-alpha and inducible NO synthase in the brain. Interestingly, coadministration of GW9662 cancelled these beneficial effects of telmisartan. Abeta 1-40 concentration in the brain was significantly decreased by treatment with telmisartan, whereas administration of GW9662 attenuated the decrease in telmisartan-mediated Abeta 1-40 concentration. Taken together, our findings suggest that even a low dose of telmisartan had a preventive effect on cognitive decline in an Alzheimer disease mouse model, partly because of PPAR-gamma activation.
authors.affiliation: Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Shitsukawa, Tohon, Ehime, Japan.
authors.forename: Kana
authors.initials: K
authors.lastname: Tsukuda
authors.forename: Masaki
authors.initials: M
authors.lastname: Mogi
authors.forename: Jun
authors.initials: J
authors.lastname: Iwanami
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Min
authors.forename: Akiko
authors.initials: A
authors.lastname: Sakata
authors.forename: Fei
authors.initials: F
authors.lastname: Jing
authors.forename: Masaru
authors.initials: M
authors.lastname: Iwai
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Horiuchi
mesh_terms: D000284:Administration, Oral; D000544:Alzheimer Disease / Q000139:chemically induced / Q000517:prevention & control; D016229:Amyloid beta-Peptides / Q000008:administration & dosage / Q000009:adverse effects* / Q000378:metabolism; D047228:Angiotensin II Type 1 Receptor Blockers / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D000813:Anilides / Q000494:pharmacology; D000818:Animals; D001562:Benzimidazoles / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D001565:Benzoates / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D002531:Cerebellum / Q000098:blood supply / Q000378:metabolism; D003072:Cognition Disorders / Q000139:chemically induced* / Q000517:prevention & control*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D007276:Injections, Intraventricular; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D051379:Mice; D008815:Mice, Inbred Strains; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D047495:PPAR gamma / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012039:Regional Blood Flow / Q000187:drug effects; D000077333:Telmisartan; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: C457499:2-chloro-5-nitrobenzanilide; D016229:Amyloid beta-Peptides; D047228:Angiotensin II Type 1 Receptor Blockers; D000813:Anilides; D001562:Benzimidazoles; D001565:Benzoates; D047495:PPAR gamma; D014409:Tumor Necrosis Factor-alpha; D052247:Nitric Oxide Synthase Type II; D000077333:Telmisartan