Autotaxin (ATX; ENPP2) is a secreted lysophospholipase D catalyzing the extracellular production of lysophosphatidic acid (LPA), a pleiotropic signaling phospholipid. Genetic and pharmacologic studies have previously established a pathologic role for ATX and LPA signaling in pulmonary injury, inflammation, and fibrosis. Here, increased ENPP2 mRNA levels were detected in immune cells from nasopharyngeal swab samples of COVID-19 patients, and increased ATX serum levels were found in severe COVID-19 patients. ATX serum levels correlated with the corresponding increased serum levels of IL-6 and endothelial damage biomarkers, suggesting an interplay of the ATX/LPA axis with hyperinflammation and the associated vascular dysfunction in COVID-19. Accordingly, dexamethasone (Dex) treatment of mechanically ventilated patients reduced ATX levels, as shown in two independent cohorts, indicating that the therapeutic benefits of Dex include the suppression of ATX. Moreover, large scale analysis of multiple single cell RNA sequencing datasets revealed the expression landscape of ENPP2 in COVID-19 and further suggested a role for ATX in the homeostasis of dendritic cells, which exhibit both numerical and functional deficits in COVID-19. Therefore, ATX has likely a multifunctional role in COVID-19 pathogenesis, suggesting that its pharmacological targeting might represent an additional therapeutic option, both during and after hospitalization.

Objective: Following evolution of COVID-19 pandemic, reports pointed on a high prevalence of thyroiditis related thyrotoxicosis. Interpretation of thyroid tests during illness, however, is hampered by changes occurring in the context of non-thyroidal illness syndrome (NTIS). In order to elucidate these findings, we studied thyroid function in carefully selected cohorts of COVID-19 positive and negative patients. Design: Cohort observational study. Methods: We measured TSH, FT4, T3 within 24hours of admission in 196 patients without thyroid disease and/or confounding medications. 102 patients were SARS-CoV-2 positive; 41 admitted in the ICU, 46 in the ward and 15 outpatients. Controls consisted of 94 SARS-CoV-2 negative patients; 39 in the ICU and 55 in the ward. We designated the thyroid hormone patterns as consistent with NTIS, thyrotoxicosis and hypothyroidism. Results: A NTIS pattern was encountered in 60% of ICU and 36% of ward patients, with similar frequencies between SARS-CoV-2 positive and negative patients (46.0% vs 46.8%, p=NS). A thyrotoxicosis pattern was observed in 14.6% SARS-CoV-2 ICU patients vs. 7.7% in ICU negative (p=NS) and, overall in 8.8% of SARS-CoV-2 positive vs. 7.4% of negative patients. In these patients thyroglobulin levels were similar to those with normal thyroid function or NTIS. The hypothyroidism pattern was rare. Conclusions: NTIS pattern is common and relates to the severity of disease rather than SARS-CoV-2 infection. A thyrotoxicosis pattern is less frequently observed with similar frequency between patients with and without COVID-19. It is suggested that thyroid hormone monitoring in COVID-19 should not differ from other critically ill patients.

Coronavirus disease-19 (COVID-19) continues to be a health threat worldwide. Increased blood lactate is common in intensive care unit (ICU) patients; however, its association with outcomes in ICU COVID-19 patients remains currently unexplored. In this retrospective, observational study we assessed whether lactate is associated with outcomes in COVID-19 patients. Blood lactate was measured on ICU admission and thereafter daily up to day 14 in 45 patients with confirmed COVID-19 pneumonia. Acute physiology and chronic health evaluation (APACHE II) was calculated on ICU admission, and sequential organ failure assessment (SOFA) score was assessed on admission and every second day. The cohort was divided into survivors and non-survivors based on 28-day ICU mortality (24.4%). Cox regression analysis revealed that maximum lactate on admission was independently related to 28-day ICU mortality with time in the presence of APACHE II (RR = 2.45, p = 0.008). Lactate’s area under the curve for detecting 28-day ICU mortality was 0.77 (p = 0.008). Mixed model analysis showed that mean daily lactate levels were higher in non-survivors (p < 0.0001); the model applied on SOFA scores showed a similar time pattern. Thus, initial blood lactate was an independent outcome predictor in COVID-19 ICU patients. The time course of lactate mirrors organ dysfunction and is associated with poor clinical outcomes.