Pleiotropic Benefits of the Angiotensin Receptor Blocker Candesartan in a Mouse Model of Alzheimer Disease.

Abstract

The angiotensin receptor blocker losartan mitigated cerebrovascular and cognitive deficits in mouse models of Alzheimer disease, in line with some clinical evidence of reduced onset and progression to Alzheimer disease. We investigated whether these benefits apply to another angiotensin receptor blocker, namely candesartan. Adult transgenic mice overexpressing a mutated form of the human APP (amyloid precursor protein) and wild-type controls were treated with vehicle or candesartan (cohort 1: 2 months, 1 mg/kg per day, osmotic subcutaneous minipumps; cohort 2: 5 months, 10 mg/kg per day in drinking water). Candesartan largely restored endothelial and smooth muscle function and reduced neuroinflammation in both cohorts, without improving sensory evoked cerebral blood flow responses. Candesartan exerted restorative effects on the reduced number of Ki67-immunopositive proliferating cells in the granule cell layer of the hippocampus but not on that of DCX (doublecortin)-positive immature granule cells, despite normalizing the length of their dendritic projections in the molecular layer. Amyloid plaque load and impaired cognitive function were unaltered by candesartan, and blood pressure was decreased in treated APP and wild-type mice. Overall, findings show that candesartan shared several advantages reported previously for losartan, but it exhibited limited cognitive benefits and stronger blood pressure lowering effects. The choice of angiotensin receptor blocker may thus be critical for therapeutic efficacy in patients with vascular diseases at high risk of developing Alzheimer disease.