The role of iron in the pathogenesis of COVID-19 and possible treatment with lactoferrin and other iron chelators.
Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie. 2021;:111228
Iron overload is increasingly implicated as a contributor to the pathogenesis of COVID-19. Indeed, several of the manifestations of COVID-19, such as inflammation, hypercoagulation, hyperferritinemia, and immune dysfunction are also reminiscent of iron overload. Although iron is essential for all living cells, free unbound iron, resulting from iron dysregulation and overload, is very reactive and potentially toxic due to its role in the generation of reactive oxygen species (ROS). ROS react with and damage cellular lipids, nucleic acids, and proteins, with consequent activation of either acute or chronic inflammatory processes implicated in multiple clinical conditions. Moreover, iron-catalyzed lipid damage exerts a direct causative effect on the newly discovered nonapoptotic cell death known as ferroptosis. Unlike apoptosis, ferroptosis is immunogenic and not only leads to amplified cell death but also promotes a series of reactions associated with inflammation. Iron chelators are generally safe and are proven to protect patients in clinical conditions characterized by iron overload. There is also an abundance of evidence that iron chelators possess antiviral activities. Furthermore, the naturally occurring iron chelator lactoferrin (Lf) exerts immunomodulatory as well as anti-inflammatory effects and can bind to several receptors used by coronaviruses thereby blocking their entry into host cells. Iron chelators may consequently be of high therapeutic value during the present COVID-19 pandemic.
Hyperferritinemia in patients with COVID-19: An opportunity for iron chelation?
Artificial organs. 2021;(2):163-167
Studies from China on COVID-19 revealed that nonsurvivors had cytokine storm with high IL-6 and hyperferritinemia. Iron liberated from necrotic cells may catalyze free radical production and amplify lipid peroxidation causing membrane dysfunction and multiorgan failure. Consequently, iron chelators have been successfully utilized in various experimental and clinical models of cytokine storm and multiorgan damage, such as in ischemia-reperfusion injury, sepsis, and infections. Since viral replication may be influenced by iron accumulation, iron chelation has been proven beneficial in a variety of viral infections, such as HIV-1, hepatitis B virus, Mengovirus, Marburg hemorrhagic fever, Enterovirus 71, and West Nile virus. In this commentary, we elaborate on the idea of considering iron chelation as a therapeutic modality in patients with severe COVID-19 infection. For critically ill patients in the ICU, intravenous deferoxamine would provide sufficient and rapid iron chelation to ameliorate cytokine storm, whereas in less severe cases an oral chelator could prevent the development of excessive inflammatory response.
Off-label tocilizumab and adjuvant iron chelator effectiveness in a group of severe COVID-19 pneumonia patients: A single center experience.
Tocilizumab (TCZ), a monoclonal recombinant antibody against IL-6 receptor, is currently used in managing the cytokine release syndrome (CRS) that occurred in coronavirus disease 2019 (COVID-19) selected cases. The primary objective of our study was to establish the effectiveness of TCZ in patients with severe or critical severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pneumonia.We retrospectively analyzed 25 consecutive patients, admitted in the Academic Emergency Hospital Sibiu, Romania from April 1, 2020 until May 25, 2020, all with confirmed SARS-CoV-2 infection and severe pneumonia. All patients were treated off-label with TCZ, beside their standard care. Adjuvant iron chelator was associated in 11 patients.Six female and 19 male patients admitted in our hospital all with confirmed SARS-CoV-2 infection and severe pneumonia as defined by Chinese Centers for Disease Control and Prevention were enrolled in this study. Seventeen of the 25 enrolled patients (68%) were seriously ill requiring noninvasive ventilation or oxygen mask, and 8 cases (32%) were critically ill requiring invasive mechanical ventilation. All patients received TCZ, and also received hydroxychloroquine, and lopinavir/ritonavir 200/50 mg for 10 days. Adjuvant iron chelator (deferasirox - marketed as Exjade) was associated in 11 patients who had ferritin serum levels above 1000 ng/mL. No side effects were encountered during infusions or after TCZ. We observed a rapid increase in arterial oxygen saturation for 20 of the 25 cases (80%) with a favorable evolution toward healing. Survivors were younger than 60 years old (80%), had less comorbidities (10% no comorbidities, 70% with 1 or 2 comorbidities), lower serum ferritin levels (30% under 1000 ng/mL), and 50% had no serum glucose elevation. Our patients with CRS had no response to corticosteroid therapy. Five out of the 25 patients had an unfavorable evolution to death. The off-label use of TCZ in patients with severe or critically ill form of SARS-CoV-2 infection had good results in our study.Off-label use of TCZ in severe and critical cases of COVID-19 pneumonia is effective in managing the "cytokine storm." Better outcomes were noted in younger patients. Associated adjuvant iron chelators may contribute to a good outcome and needs to be confirmed in larger studies.
COVID-19 as part of the hyperferritinemic syndromes: the role of iron depletion therapy.
Immunologic research. 2020;(4):213-224
SARS-CoV-2 infection is characterized by a protean clinical picture that can range from asymptomatic patients to life-threatening conditions. Severe COVID-19 patients often display a severe pulmonary involvement and develop neutrophilia, lymphopenia, and strikingly elevated levels of IL-6. There is an over-exuberant cytokine release with hyperferritinemia leading to the idea that COVID-19 is part of the hyperferritinemic syndrome spectrum. Indeed, very high levels of ferritin can occur in other diseases including hemophagocytic lymphohistiocytosis, macrophage activation syndrome, adult-onset Still's disease, catastrophic antiphospholipid syndrome and septic shock. Numerous studies have demonstrated the immunomodulatory effects of ferritin and its association with mortality and sustained inflammatory process. High levels of free iron are harmful in tissues, especially through the redox damage that can lead to fibrosis. Iron chelation represents a pillar in the treatment of iron overload. In addition, it was proven to have an anti-viral and anti-fibrotic activity. Herein, we analyse the pathogenic role of ferritin and iron during SARS-CoV-2 infection and propose iron depletion therapy as a novel therapeutic approach in the COVID-19 pandemic.