Higher prevalence of spontaneous cerebral vasculopathy and cerebral infarcts in a mouse model of sickle cell disease

Abstract

Stroke is a dramatic complication of sickle cell disease (SCD), which is associated with cerebral vasculopathies including moya moya, intravascular thrombi, cerebral hyperemia, and increased vessel tortuosity. The spontaneous occurrence of these pathologies in the sickle cell mouse model has not been described. Here, we studied Townes humanized sickle cell and age-matched control mice that were 13 months old. We used in vivo two-photon microscopy to assess blood flow dynamics, vascular topology, and evidence of cerebral vasculopathy. Results showed that compared to controls, sickle cell mice had significantly higher red blood cell (RBC) velocity (0.73 mm/s vs. 0.55 mm/s, p = 0.013), capillary vessel diameter (4.84 µM vs. 4.50 µM, p = 0.014), and RBC volume flux (0.015 nL/s vs. 0.010 nL/s, p = 0.021). Also, sickle cell mice had significantly more tortuous capillary vessels (p < 0.0001) and significantly shorter capillary vessel branches (p = 0.0065) compared to controls. Sickle cell mice also had significantly higher number of capillary occlusive events (3.4% vs. 1.9%, p < 0.0001) and RBC stalls (3.8% vs. 2.1%, p < 0.0001) in the cerebral capillary bed. In post-mortem immunohistochemical analyses, sickle cell mice had a 2.5-fold higher frequency of cortical microinfarcts compared to control mice. Our results suggest that aged Townes sickle cell mice spontaneously develop SCD-associated cerebral vasculopathy.