Structural and functional disruption of vascular smooth muscle cells in a transgenic mouse model of amyloid...

Area of Science:

• Neuroscience
• Vascular Biology
• Pathology

Background:

• Cerebral amyloid angiopathy (CAA) involves amyloid Abeta peptide deposition in cerebral vessels.
• CAA can weaken vessel walls, increasing risk of hemorrhagic stroke.
• The Tg2576 mouse model exhibits age-dependent amyloid precursor protein overexpression and CAA.

Purpose of the Study:

• To investigate the structural and functional changes in smooth muscle cells (SMCs) within pial vessels affected by amyloid deposition in Tg2576 mice.
• To determine the timing of SMC disruption relative to cell death.
• To assess the functional response of affected SMCs to vasodilators.

Main Methods:

• Utilized the Tg2576 transgenic mouse model of cerebral amyloid angiopathy.
• Employed multiphoton imaging for in vivo visualization of pial vessel walls.
• Performed functional assays using a closed-cranial window preparation to test vasodilator responses.

Main Results:

• Amyloid deposition in Tg2576 mice leads to structural disorganization of SMCs in pial vessel walls.
• SMC disorganization occurs prior to the onset of cell death.
• Disorganized SMCs exhibit impaired responsiveness to both endothelial-dependent and endothelial-independent vasodilators.

Conclusions:

• Amyloid deposition in cerebral vessels causes structural and functional damage to smooth muscle cells.
• SMC dysfunction precedes cell death, indicating an early pathogenic mechanism in CAA.
• Impaired vascular reactivity in CAA contributes to cerebrovascular dysfunction and stroke risk.