Abstract Body: SARS-CoV-2 infection has been linked to long-term atherosclerotic cardiovascular outcomes, even after mild COVID-19. Mechanistic studies have been limited by the lack of animal models that recapitulate mild infection. Building on our prior findings of macrophage infection in human coronaries, we established a SARS-CoV-2 infection model in atherosclerotic Golden Syrian hamsters. This model leverages their natural susceptibility to mild-to-moderate, human-like COVID-19 without genetic modification to investigate vascular infection and long-term cardiovascular outcomes.
Male hamsters received AAV8-hPCSK9 (i.p.) followed by Western diet (WD) for 16 weeks or (n=100) remained on chow diet (n=40). WD-fed hamsters developed hypercholesterolemia (total cholesterol: 296.9±27.28 mg/mL), with marked weight gain (~21.78±2.46%). Animals were randomized to either SARS-CoV-2 (n=75; USA-WA1/2020, 1000 PFU, i.n.) or mock infection (n=65).
Atherosclerotic hamsters exhibited higher lung titers at 3 days post-infection (dpi) compared to controls (8.25 ± 1.41 vs 6.62 ± 0.98 log₁₀ PFUml^-1), with undetectable titers by 10 dpi. Viral protein and RNA were detectable in lungs as early as 3 dpi, with lung pathology peaked at 10 dpi and resolved by 30 dpi. Aorta infection was detected at 3 dpi in both atherosclerotic and control hamsters (1.84±0.72 vs. 2.31±0.79 log₁₀ PFUml^-1), indicating that viral replication is independent of atherosclerotic burden.
Single-cell RNA sequencing of aortic arches from atherosclerotic (n=24) and control (n=21) hamsters revealed that SARS-CoV-2 infection upregulated cytokine, interferon, and antiviral responses in vascular cells. Myeloid cells were the predominant SARS-CoV-2–infected population in the aorta, with higher vRNA levels in atherosclerotic than healthy vessels, particularly within S100a9+ inflammatory and Gpnmb+ foamy macrophage subsets. Infection induced rapid myeloid compartment expansion and activation by 3 dpi, marked by upregulated inflammatory signaling, cytokine programs, and antiviral response genes. Although viral clearance was achieved by 10 dpi, aortic myeloid cells exhibited persistent inflammation-associated transcriptional and epigenetic reprogramming at 30 dpi, indicating sustained myeloid activation after infection.
Together, these findings show that acute vascular SARS-CoV-2 infection drives sustained myeloid inflammatory reprogramming, providing a mechanistic link between infection and long-term cardiovascular risk.