Background: Coronavirus disease 19 (COVID-19) can develop into a severe respiratory syndrome that results in up to 40% mortality. Acute lung inflammatory edema is a major pathological finding in autopsies explaining O₂ diffusion failure and hypoxemia. Only dexamethasone has been shown to reduce mortality in severe cases, further supporting a role for inflammation in disease severity. SARS-CoV-2 enters cells employing angiotensin-converting enzyme 2 (ACE2) as a receptor, which is highly expressed in lung alveolar cells. ACE2 is one of the components of the cellular machinery that inactivates the potent inflammatory agent bradykinin, and SARS-CoV-2 infection could interfere with the catalytic activity of ACE2, leading to the accumulation of bradykinin. Methods: In this case control study, we tested two pharmacological inhibitors of the kinin–kallikrein system that are currently approved for the treatment of hereditary angioedema, icatibant, and inhibitor of C1 esterase/kallikrein, in a group of 30 patients with severe COVID-19. Results: Neither icatibant nor inhibitor of C1 esterase/kallikrein resulted in changes in time to clinical improvement. However, both compounds were safe and promoted the significant improvement of lung computed tomography scores and increased blood eosinophils, which are indicators of disease recovery. Conclusions: In this small cohort, we found evidence for safety and a beneficial role of pharmacological inhibition of the kinin–kallikrein system in two markers that indicate improved disease recovery.

Background: The coronavirus disease-19 pandemic affected millions of people and its long-term impact on the health of survivors is under evaluation. Objectives: In this study, we hypothesized that severe coronavirus disease-19 could promote long-term changes in the blood levels of hormones and growth factors known to be involved in the regulation of ageing. Methods: We evaluated 49 patients that recovered from severe COVID-19 and compared them with matched controls that were never infected by the virus. The blood levels of growth hormone, insulin-like growth factor-1, insulin, brain-derived neurotrophic factor, nerve growth factor, oxytocin, ghrelin, platelet-derived growth factor, fibroblast growth factor-1, and transforming growth factor-beta were determined using enzyme-linked immunosorbent assays. Results: After six months of recovery, patients presented reduced blood levels of growth hormone, insulin-like growth factor-1, brain-derived neurotrophic factor, and platelet-derived growth factor. Fifteen months after, the reductions in the blood levels of all four hormones/growth factors persisted. Conclusions: Our study advances the field by identifying hormones and growth factors involved in ageing that undergo persistent changes in patients that recover from severe COVID-19. Further studies could explore the potential of the identified hormones/growth factors as therapeutic targets for the late complications and accelerated ageing that may affect patients recovering from severe COVID-19.