ABSTRACT
Severe imbalance in iron metabolism among SARS-CoV-2 infected patients is prominent in every symptomatic (mild, moderate to severe) clinical phase of COVID-19. Phase-I - Hypoxia correlates with reduced O2 transport by erythrocytes, overexpression of HIF-1α, altered mitochondrial bioenergetics with host metabolic reprogramming (HMR). Phase-II - Hyperferritinemia results from an increased iron overload, which triggers a fulminant proinflammatory response - the acute cytokine release syndrome (CRS). Elevated cytokine levels (i.e. IL6, TNFα and CRP) strongly correlates with altered ferritin/TF ratios in COVID-19 patients. Phase-III - Thromboembolism is consequential to erythrocyte dysfunction with heme release, increased prothrombin time and elevated D-dimers, cumulatively linked to severe coagulopathies with life-threatening outcomes such as ARDS, and multi-organ failure. Taken together, Fe-R-H dysregulation is implicated in every symptomatic phase of COVID-19. Fe-R-H regulators such as lactoferrin (LF), hemoxygenase-1 (HO-1), erythropoietin (EPO) and hepcidin modulators are innate bio-replenishments that sequester iron, neutralize iron-mediated free radicals, reduce oxidative stress, and improve host defense by optimizing iron metabolism. Due to its pivotal role in 'cytokine storm', ferroptosis is a potential intervention target. Ferroptosis inhibitors such as ferrostatin-1, liproxstatin-1, quercetin, and melatonin could prevent mitochondrial lipid peroxidation, up-regulate antioxidant/GSH levels and abrogate iron overload-induced apoptosis through activation of Nrf2 and HO-1 signaling pathways. Iron chelators such as heparin, deferoxamine, caffeic acid, curcumin, α-lipoic acid, and phytic acid could protect against ferroptosis and restore mitochondrial function, iron-redox potential, and rebalance Fe-R-H status. Therefore, Fe-R-H restoration is a host biomarker-driven potential combat strategy for an effective clinical and post-recovery management of COVID-19.
ABSTRACT
The main pathological conditions characterized by disturbances of iron metabolism have been analyzed, including anemias, hemochromatosis, inflammatory, autoimmune and neurodegenerative disorders, chronic renal insufficiency, infectious diseases (including COVID-19), etc. Strategies of their pharmacological correction and risks of common adverse effects development are considered for the potential targets of pharmacotherapy and possible groups of medications including inhibitors of prolyl-4-hydroxylase, inhibitors of bone morphogenetic proteins (BMP 6), ferroportin and hepcidin activity, inhibitors of hypoxia-inducible factor (HIF-1a) and divalent metal transporter (DMT-1). Copyright © 2022 Izdatel'stvo Meditsina. All rights reserved.
ABSTRACT
Mucormycosis is a rare fungal infection mainly affecting immunocompromised patients. Recently, an alarming rise in cases of mucormycosis was observed in patients undergoing COVID-19 treatment. Commonly, this fungal infection is caused by Rhizopus spp., Mucor spp., and Lichtheimia spp., although the genera of other Mucorales such as Saksenaea, Rhizomucor, Cunninghamella, and Apophysomyces may also be involved. A number of factors such as high concentration of zinc, iron and hypoxia induced acidosis promote the growth of fungi, thereby increasing the risk of mucormycosis multiple folds. Iron chelators (deferasirox and deferiprone) and zinc chelators (clioquinol, phenanthroline and N,N,N′,N′-tetrakis-(2-pyridylmethyl)ethane-1,2-diamine) have been reported to inhibit the growth of fungi in a number of in vitro and animal studies. Correction of metabolic acidosis by administration of bicarbonate or glycine reduces the susceptibility of patients to the invasion by fungal species. However, these factors have largely been ignored while deciding the treatment strategy for mucormycosis and first line treatment for the management of mucormycosis continues to be the expensive lipid based formulation of amphotericin B. Treatment with isavuconazole which is proposed as the second choice is reported to be more cost effective. Therefore, it is proposed that a combination of antifungal agent (isavuconazole) with zinc and iron chelators (deferasirox and clioquinol respectively) along with alkalizer (glycine buffer) could be an effective and multi-target approach for the treatment of mucormycosis while being cost effective also.
ABSTRACT
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.