Targeting the catecholamine-cytokine axis to prevent SARS-CoV-2 cytokine storm syndrome

The mortality of Coronavirus disease 2019 (COVID-19) appears to be driven by acute respiratory distress syndrome (ARDS) and a dysregulated immune response to SARS-CoV-2. Emerging evidence suggests that a subset of COVID-19 is characterized by the development of a cytokine storm syndrome (CSS), and interleukin (IL)-6 levels are predictors of COVID-19 severity and in-hospital mortality. Targeting hyper-inflammation in COVID-19 may be critical for reducing mortality. Catecholamines enhance inflammatory injury by augmenting the production of IL-6 and other cytokines through a self-amplifying feed-forward loop in immune cells that requires alpha-1 adrenergic receptor (α1-AR) signaling. Prophylactic inhibition of catecholamine synthesis with the α1-AR antagonist prazosin reduced catecholamines and cytokine responses in mice, and resulted in markedly increased survival following various hyper-inflammatory stimuli. These findings offer a rationale for studying α1-AR antagonists in the prophylaxis of patients with COVID-19-CSS and ARDS. As high infection rates threaten to overwhelm hospital capacity during this pandemic, preventative approaches that ameliorate COVID-19 severity and reduce excessive mortality are desperately needed. We hypothesize that treatment with prazosin of individuals who test positive for SARS-CoV-2 could reduce catecholamine surges, secondary cytokine dysregulation, and mortality. To investigate a potential role for α1-AR antagonists in preventing poor outcomes in ARDS, we conducted a retrospective analysis of hospitalized patients diagnosed with ARDS. Using data from the Truven Health MarketScan Research Database (2010-2017), we identified 13,125 men (age 45-64) with ARDS, of whom 655 patients (5.0%) were prescribed α1-AR antagonists in the previous year. Applying logistic regression models, we found that patients with prior use of α1-AR antagonists had lower odds of invasive mechanical ventilation compared to non-users (adjusted OR=0.75, 95% CI 0.59-0.95, p=0.019). Perhaps more importantly, those patients had a ~36% lower incidence of both being ventilated and dying in the hospital (adjusted OR=0.59, 95% CI 0.34-0.95, p=0.042). By contrast, prior use of beta-adrenergic receptor (β-AR) antagonists was not correlated with either outcome. We extended these analyses to patients admitted with pneumonia. Of 108,956 subjects in this cohort, 5,498 patients (5.0%) were taking α1-AR antagonist. Similar to ARDS, patients with pneumonia on α1-AR antagonists (but no β-AR antagonists) had a lower odds of mechanical ventilation (adjusted OR=0.83, 95% CI 0.75-0.92, p<0.001) and of both being ventilated and dying in the hospital (adjusted OR=0.77, 95% CI 0.62-0.94, p=0.014) compared to non-users. Mirroring findings from pre-clinical models, these data support a clinical rationale to study α1-AR antagonists in the prevention of severe complications of pneumonia, ARDS, and COVID-19. Prospective, randomized clinical trials of alpha-1 receptor antagonists (e.g. prazosin) administered prior to the onset of severe symptoms are needed to assess their efficacy in preventing CSS and reducing mortality in COVID-19.