Higher inflammatory cytokines in long-covid with cardiovascular symptoms after acute severe COVID-19? A two-year, pre-vaccine, longitudinal, exploratory, nested cohort

Abstract Introduction Acute severe COVID-19 in the pre-vaccination era caused worse Long-covid (LC) clinical presentation in comparison to the acute severe disease in post-vaccination period. Severe COVID-19 leads to several physiological and immune disturbances, which may persist for a long period. LC, therefore, is the persistence, development or fluctuation of clinical and/or laboratory alterations, which linger for at least twelve weeks. LC has a complex etiology and affects millions of individuals worldwide. Understanding the pathophysiology and the immune response associated to cardiovascular phenotype of individuals with LC in longitudinally designed studies may help to advance targeted treatments and improve patient prognosis. Objective To longitudinally assess the level of pro-inflammatory cytokines (IL-1β and TNF-α) in individuals with lingering cardiovascular disturbances two-years after acute severe COVID-19. Methods and results This was a longitudinal nested cohort of hospitalized individuals who had severe COVID-19 in 2020 (pre-vaccine era), developed LC and present lingering cardiovascular clinical symptomology after two years of disease. The pro-inflammatory profile was assessed in five timepoints: in acute disease (D1, D14 and D28), at 120 days and at 720 days post hospitalization. Also, clinical assessments were performed at D120 and D720. Circulating cytokines were quantified in the patients' serum samples using the Flow Cytometry CBA (Cytometric Bead Array) with the Cytometric Bead Array (CBA) Human Inflammatory Cytokine Kit (Becton, Dickinson and Company BD Life Sciences – Biosciences 2350, Qume Drive, San Jose) following the manufacturer’s guidelines. 69 individuals completed all assessments. The participants were stratified in two groups: those reporting cardiovascular symptomology (Lccard) and those without (Lcnocard). Reported cardiovascular symptoms were arrhythmia, systemic arterial hypertension, chest pain, heart failure and palpitation. 31/69 (45%) presented cardiovascular symptoms two-years after acute severe COVID-19. Age was similar between groups (51±13 vs 57±14 years, p=0.081, in Lccard and Lcnocard, respectively). Individuals in the Lccard group were predominantly men (23/31, 74% vs 22/38, 57%, p0.05). The pro-inflammatory cytokine profile of the study participants is characterized in Figure 1. The longitudinal assessment of cytokine levels among participants with Lccard showed significantly higher levels of IL-1β and TNF-α between D1 vs D720 (p0.001); D7 vs D720 (p0.001), and D14 vs D720 (p0.001). Conclusion The pro-inflammatory profile of individuals with LC associated cardiovascular symptoms is significantly elevated two years after acute severe COVID-19. Elevated levels of IL-6 and TNF-α have been associated with cardiovascular morbidity and may lead to chronic cardiovascular alterations and a worse prognosis in this population.