Simvastatin restored vascular reactivity, endothelial function and reduced string vessel pathology in a mouse model...

Area of Science:

• Neuroscience
• Pharmacology
• Vascular Biology

Background:

• Cerebrovascular dysfunction is a key feature of Alzheimer's disease (AD) and vascular dementia (VaD), involving more than just amyloid-β (Aβ) pathology.
• Transforming growth factor-β1 (TGF) transgenic mice exhibit vascular pathologies, including structural changes and capillary degeneration, mimicking aspects of VaD.
• Previous studies showed simvastatin ameliorates Aβ-related deficits in AD models, but its effects on Aβ-independent vascular dysfunction remain unclear.

Purpose of the Study:

• To investigate the efficacy of simvastatin in treating cerebrovascular dysfunction and cognitive deficits in aged TGF mice, models of Aβ-independent vascular pathology.
• To assess simvastatin's impact on cerebrovascular reactivity, structure, and specific pathological markers in the context of TGF-β1 overexpression.

Main Methods:

• Aged TGF mice were treated with simvastatin to evaluate its effects on cerebrovascular responses, including nitric oxide (NO) and KATP channel-mediated dilations, and endothelin-1-induced contractions.
• Vascular structure, including arteriogenic remodeling and string vessel pathology, was assessed.
• Cerebrovascular levels of pro-fibrotic proteins, calcification markers, and gliosis were quantified.
• Cognitive performance was evaluated in simvastatin-treated and control TGF mice.

Main Results:

• Simvastatin restored normal nitric oxide (NO) and KATP channel-mediated vascular dilations and reduced abnormal contractions.
• The treatment significantly ameliorated vasculopathy, characterized by arteriogenic remodeling and string vessel degeneration.
• Simvastatin did not reduce gliosis or markers of vascular fibrosis and calcification.
• No significant improvement in cognitive decline was observed in TGF mice following simvastatin treatment.

Conclusions:

• Simvastatin demonstrates potent beneficial effects on endothelial and smooth muscle cell function, improving vasomotor responses and preserving capillary integrity in a model of Aβ-independent cerebrovascular dysfunction.
• The findings suggest simvastatin's potential therapeutic value for cerebrovascular complications in vascular dementia (VaD) and Alzheimer's disease (AD), particularly those not solely driven by amyloid pathology.