Abstract Body: Introduction: Aging and chronic cerebral hypoperfusion (CCH) are major risk factors for Vascular contribution to cognitive impairment and dementia (VCID), which is a heterogeneous group of disorders characterized by cognitive deficits secondary to cerebrovascular pathology. Importantly, patients with CCH show enhanced brain iron deposition and iron metabolism dysregulation, which have been associated with different types of dementia and neurodegenerative disorders, such as Alzheimer’s disease, Huntington’s disease, VCID, etc. Recent studies have proposed different mechanisms involved in VCID induced by CCH in young small rodents. However, no study has elucidated the molecular changes that occur in CCH models using aged animals. Thus, we hypothesize that brain iron metabolism is dysregulated in an aged mouse model of VCID.

Methodology: We induced CCH through bilateral carotid artery stenosis (BCAS) by ligating carotid arteries with 0.18 mm diameter coils in 17-18 months C57BL/6 mice of both sexes. Sham mice underwent the same surgery without coil ligation. After surgery, mice were maintained for 5 months; then, they were tested for open field, elevated plus maze, and fear conditioning. After behavior tests, their brains were analyzed for histochemistry analysis and qPCR.

Results: We observed that BCAS mice showed increased velocity (p=0.016) and distance moved (p=0.009) in the open field test, and they showed a higher number of visits to open arms (p=0.026) in the elevated plus maze, compared with sham mice. Furthermore, the percentage of freezing time in the fear conditioning test was significantly reduced in BCAS mice (p=0.037), compared with sham mice. We also found that the number (p=0.039) and size (p=0.003) of iron deposits increased in the striatum of BCAS mice, compared with sham mice. Interestingly, the relative expression of genes involved in iron metabolism such as Ncoa4 (codes mediator of ferritinophagy) and Ftl1 (coding for iron storage protein ferritin light-chain), were significantly reduced (p=0.007, p=0.001, respectively) in the striatum, but not in the cortex, of BCAS mice, compared with sham mice.

Conclusion: Our data indicates that BCAS mice showed enhanced anxiety-like behavior and impaired conditioning memory, increased iron deposition, and impaired iron metabolism in their striatum, compared with sham mice. Next, we will determine if restoring brain iron metabolism in BCAS mice can mitigate CCH-induced phenotype.