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543 The link between preexisting hypertension and COVID-19 severity in a hamster model
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- Branka Stanic, Seth Hawks, Nataliia Shults, Hong Ji, Aline M.A. de Souza, Xie Wu, Juan M. Saavedra, Kathryn Sandberg, Nisha Duggal
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- Journal:
- Journal of Clinical and Translational Science / Volume 8 / Issue s1 / April 2024
- Published online by Cambridge University Press:
- 03 April 2024, p. 162
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OBJECTIVES/GOALS: Hypertension is a major risk factor for coronavirus disease 2019 (COVID-19) severity. Our goal was to determine if hypertension worsens lung pathology induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in hamsters. METHODS/STUDY POPULATION: Male hamsters (7-8 weeks old) were infused with angiotensin II (AII; 200 ng/kg/min via osmotic minipump) for 4 weeks to induce hypertension. During the last week of the infusion, the hamsters were inoculated intranasally with vehicle (V) or SARS-CoV-2 (S; 1 x 105 plaque forming units/ml). Half of the hamsters were sacrificed 1 day post-inoculation (dpi-1) and the other half on dpi-6. Two scoring systems were applied to lung tissue sections stained with hematoxylin and eosin to determine the degree and severity of lung pathology: the first system assessed all pertinent alterations in the lungs, while the second system only assessed the pathology related to the pulmonary vasculature. Lung histopathology scores were calculated as the sum of the airway and lung alveolar scores in arbitrary units (AU). RESULTS/ANTICIPATED RESULTS: Studies revealed that the SARS-CoV-2-infected hamsters exhibited a 76-fold higher total airway score compared to vehicle controls [(AU): V, 0.25 ± 0.1; S, 19.00 ±1.35; p<0.05; n=4]. Total lung alveolar scores (27-fold) [(AU): V, 0.30 ± 0.11; S, 8.0 ± 4.1; p<0.05; n=4] and total vascular scores (17-fold) [(AU): V, 0.35 ± 0.2; S, 6.0 ±1.4; p<0.05; n=4] were also markedly higher compared to controls on dpi-1. AII increased blood pressure, which was sustained through the 4-week infusion period. Under these conditions, body weight slightly dropped by 4.5%. Ongoing studies are assessing the effect of hypertension on the % of airway, alveoli and vessels affected, airway and alveolar severity, and bronchiolar epithelial and type II pneumocyte hyperplasia. DISCUSSION/SIGNIFICANCE: Establishing the hypertensive hamster as a small animal model of COVID-19 will facilitate investigations into why preexisting hypertension is a risk factor for disease severity. These studies could lead to the development of novel therapeuticsfor treating COVID-19 patients with hypertension.
396 Brain pathophysiology in SARS-CoV-2 disease
- Branka Milicic Stanic, Aline M.A. de Souza, Hong Ji, Xie Wu, Robert C. Speth, Nisha K. Duggal, Carolyn A. Ecelbarger, Juan M. Saavedra, Dexter L. Lee, Kathryn Sandberg
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- Journal:
- Journal of Clinical and Translational Science / Volume 6 / Issue s1 / April 2022
- Published online by Cambridge University Press:
- 19 April 2022, pp. 74-75
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OBJECTIVES/GOALS: The SARS-CoV-2 (Severe Acute Respiratory Syndrome CoronaVirus-2), which underlies the current COVID-19 pandemic, among other tissues, also targets the central nervous system (CNS). The goal of this study is to investigate mechanisms of neuroinflammation in Lipopolysaccharides (LPS)-treated mouse model and SARS-CoV-2-infected hamsters. METHODS/STUDY POPULATION: In this research I will assay vascular reactivity of cerebral vessels to assess vascular dysfunction within the microcirculation. I will determine expression of proinflammatory cytokines, coagulation factors and AT1 receptors (AT1R) in isolated microvessels from the circle of Willis to assess inflammation, thrombosis and RAS activity in the microvasculature. LPS and SARS-CoV-2, are both associated with coagulopathies and because of that I will measure concentration of PAI-1, von Willebrand Factor, thrombin and D-dimer to assess the thrombotic pathway in the circulation. Histology and immunohistochemistry will assess immune cell type infiltration into the brain parenchyma, microglia activation and severity of neuroinflammation and neural injury. RESULTS/ANTICIPATED RESULTS: We hypothesize that under conditions of reduced ACE2 (e.g., SARS-CoV-2 infection), AT1R activity is upregulated in the microvasculature. In the presence of an inflammatory insult, these AT1Rs promote endothelialitis and immunothrombosis through pro-thrombotic pathways and pro-inflammatory cytokine production leading to endothelial dysfunction in the microvasculature, blood brain barrier (BBB) injury, deficits in cognition and increased anxiety. We will test this hypothesis through 2 aims: Aim 1: Determine the role of the pro-injury arm of the RAS in the pathophysiology of the brain in animal models of neuroinflammation and COVID-19. Aim 1: Determine the role of the protective arm of the RAS in the pathophysiology of the brain in animal models of neuroinflammation and COVID-19. DISCUSSION/SIGNIFICANCE: This study will provide insights that will complement on-going clinical trials on angiotensin type 1 receptor (AT1R) blockers (ARBs) in COVID-19. This research is a necessary first step in understanding mechanisms of brain pathogenesis that can set the groundwork for future studies of more complex models of disease.