The Potential of Thyroid Hormone Therapy in Severe COVID-19: Rationale and Preliminary Evidence.

Tissue hypoxia is one of the main pathophysiologic mechanisms in sepsis and particularly in COVID-19. Microvascular dysfunction, endothelialitis and alterations in red blood cell hemorheology are all implicated in severe COVID-19 hypoxia and multiorgan dysfunction. Tissue hypoxia results in tissue injury and remodeling with re-emergence of fetal programming via hypoxia-inducible factor-1α (HIF-1a)-dependent and -independent pathways. In this context, thyroid hormone (TH), a critical regulator of organ maturation, may be of relevance in preventing fetal-like hypoxia-induced remodeling in COVID-19 sepsis. Acute triiodothyronine (T3) treatment can prevent cardiac remodeling and improve recovery of function in clinical settings of hypoxic injury as acute myocardial infarction and by-pass cardiac surgery. Furthermore, T3 administration prevents tissue hypoxia in experimental sepsis. On the basis of this evidence, the use of T3 treatment was proposed for ICU (Intensive Care Unit) COVID-19 patients (Thy-Support, NCT04348513). The rationale for T3 therapy in severe COVID-19 and preliminary experimental and clinical evidence are discussed in this review.

Acute triiodothyronine treatment and red blood cell sedimentation rate (ESR) in critically ill COVID-19 patients: A novel association?

Sepsis and septic shock result in impaired microcirculation and red blood cell rheology which lead to tissue hypoxia and multi-organ failure. Early administration of triiodothyronine prevents tissue hypoxia in experimental sepsis. In this context, a clinical trial was initiated to test the efficacy of acute triiodothyronine administration to combat tissue hypoxia in critically ill COVID19 patients. Here, we provide preliminary data from interim analysis of this study showing a novel acute effect of triiodothyronine on erythrocyte sedimentation rate which may have an important therapeutic impact on red blood cell rheology and tissue hypoxia in sepsis and particular in COVID19 critical illness.Trial registration: ClinicalTrials.gov, NCT04348513. Registered 16 April 2020, https://clinicaltrials.gov/ct2/show/NCT04348513.