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.

Susceptibility to capillary plugging can predict brain region specific vessel loss with aging

“…In fact, white blood cells tend to become stickier in various disease states that experience large numbers of microvascular obstructions. For example, a model of sickle cell disease displays a large number of capillary stalling events (Hyacinth et al, 2017), which correlates with the presentation of higher white blood cell counts and increased expression of l-selectin and αMβ integrin in patients (Okpala et al, 2002). These same patients show symptomatic improvements with treatments that reduce leukocyte adhesion molecule expression (Okpala et al, 2002).…”

Renal protection by atorvastatin in a murine model of sickle cell nephropathy

“…The humanized knock‐in sickle cell mice utilized in this study provides an excellent model of SCD that recapitulates all the major features of sickle cell pathology in humans (Wu et al , ; Hyacinth et al , ; Sun et al , ). The experimental and control groups of mice studied in this experiment were similar at baseline.…”

Age and neuroinflammation are important components of the mechanism of cognitive and neurobehavioral deficits in sickle cell disease

“…Furthermore, a sample size of 4 mice would be adequate to show statistically significant differences for the histological studies based on our prior published work in sickle cell mice. [34][35][36] Mice for this study were breed at the Emory University managed breeding services, weaning at 3 -4 weeks of age and were housed with a 12-hour light/dark cycle with water and feed provided ad libitum. Mice were allowed to age naturally until ready for use in our experiments described below.…”

“…The general approach used for immunohistochemistry in our laboratory has already been published. 34 For primary antibody labeling, free-floating tissue sections (50µm thick) obtained from post-fixed brain samples, were placed in a scintillating glass vial containing antibodies (diluted in antibody diluting solution for a total of 2mls volume) from one of the panels described above and after incubating for 16-24 hours at room temperature on a nutating shaker, the sections were washed with PBS and then incubated for 2 hours with the respective secondary antibody. Sections were mounted using Fluoromout G and imaged at 20X using a confocal microscope (Leica SP8, Leica Microsystems Inc.).…”