key: cord-1045027-d2bn6mmb authors: Hosseinzadeh, Mohammad Hossein; Shamshirian, Amir; Ebrahimzadeh, Mohammad Ali title: Dexamethasone vs COVID‐19: An experimental study in line with the preliminary findings of a large trial date: 2020-12-30 journal: Int J Clin Pract DOI: 10.1111/ijcp.13943 sha: d00678502c2e34b890a067bd5e8fac1cecc0fe58 doc_id: 1045027 cord_uid: d2bn6mmb BACKGROUND: The preliminary report of the RECOVERY large randomised controlled trial indicated a promising survival effect for dexamethasone therapy of coronavirus disease 2019 (COVID‐19). This study aimed to investigate the anti‐hypoxic activities of dexamethasone to understand a possible mechanism of its action in hypoxia‐induced lethality through experimental models of hypoxia. METHODS: In this investigation, 84 Male BALB/c mice were randomly divided into groups of seven (12 groups). Treatment groups received 10 days of dexamethasone intraperitoneal injection at both human dose (~0.1 mg/kg) and the animal does (~1 mg/kg). Control negative and positive groups were treated with 10 ml/kg of normal saline and 30 mg/kg of propranolol, respectively. Three experimental models of hypoxia, asphyctic, circulatory, and hemic were applied in this study. RESULTS: The findings showed that dexamethasone significantly prolonged the latency for death in the asphyctic model concerning the control group in both humans (P < .0001) and animal dose (P < .0001). The results were also highly significant for both doses in the hemic model (P < .001). In the circulatory model, although a small increase was observed in death prolongation, results were not statistically significant for both doses in this model (P > .05). CONCLUSIONS: This experimental in vivo investigation demonstrated an excellent protective effect for 10 days of dexamethasone treatment against hypoxia, especially in asphyctic and hemic models. In addition to promising dexamethasone outcomes, using propranolol as the positive control illustrated a very substantial anti‐hypoxic effect even much better than dexamethasone in all models. It seems that propranolol would be a safe, potential, and prudent choice to invest in treating COVID‐19 patients. Such medications have been widely used to improve outcomes in individuals with acute respiratory distress syndrome (ARDS), pneumonia, and septic shock. 2, 3 In recent years, different well-designed clinical trials have demonstrated promising clinical benefit for corticosteroids in ARDS and septic shock. [4] [5] [6] In this case, one of the conflicting treatment choices since the emergence of the COVID-19 was dexamethasone. The preliminary report of the RECOVERY large randomised controlled trial 7 indicated a promising survival effect for dexamethasone therapy of coronavirus disease 2019 patients at a dose of 6 mg q.d. for up to 10 days. The majority of the patients infected with SARS-CoV-2 are asymptomatic or only manifest a mild disease. However, the infection can lead to critical stages and cause acute hypoxemic respiratory failure requiring supplemental oxygen. 7, 8 Remarkably, the RECOVERY study indicated that the treatment approach was significant amongst patients with hypoxemia under the invasive/non-invasive respiratory support, but not in mild patients without hypoxemia and breathing support. As a corticosteroid, dexamethasone widely affects innate and adaptive immunity, especially as an anti-inflammatory agent. Regardless of dexamethasone's studied activities, following the RECOVERY study results, we aimed to simulate this study's treatment approach and investigate the anti-hypoxic activities of dexamethasone to understand a possible mechanism of its action in hypoxia-induced lethality through experimental models of hypoxia. All the experimental procedures were performed based on the US National Institutes of Health guidelines of the Laboratory Animal Care and Use. 9 The Animal Ethical Committee of Mazandaran University of Medical Sciences has approved the experimental protocol (IR.MAZUMS.REC.1399.546). Male BALB/c mice were purchased at 10-12 weeks of age from Royan Institute (Tehran, Iran). In this investigation, 84 Male BALB/c mice (32.98 ± 1.04 g) were randomly divided into groups of seven (12 groups) in polypropylene cages at ambient temperature, 25 ± 1°C and 45%-55% relative humidity, with a 12 hours light: 12 hours dark cycle (lights on at 7 am). The animals had free access to standard water, pellet fuel by ad libitum access. Experiments were performed between 8:00 and 14:00 hours. According to Table 1 , treatment groups received 10 days of dexamethasone intraperitoneal (ip) injection at both human dose (6 mg once daily based on body surface area = ~0.1 mg/kg) and the animal does (~1 mg/kg for mice). 10 Control negative groups were treated with 10 ml/kg of normal saline and control positive groups with 30 mg/kg of propranolol at the same time plan. Three experimental models of hypoxia; asphyctic, circulatory, and hemic were applied in this study. Asphyctic hypoxia model After the RECOVERY press release, several multicentre RCTs have investigated the effects of corticosteroids COVID-19 patients. These studies and the WHO Rapid Evidence Appraisal for COVID-19 Therapies (REACT) meta-analysis indicated a promising clinical benefit for corticosteroids against COVID-19 patients, especially in severe condition. [11] [12] [13] [14] In this regard, some physicians may ask why Hypoxia condition leads to intense physiological stress and induces a wide range of toxic effects at the cellular level. Oxygen as a source of ROS formation is a vital component of organisms and normal redox reactions in the cell. 15 It has been indicated that both hypoxia and hyperoxia can promote oxidative damage and increase the risk of morbidity and mortality. 16 Studies demonstrated that hypoxia interrupts mitochondrial function and increases ROS production and oxidative stress, which could trigger apoptosis signalling. 17, 18 The brain uses a large amount of oxygen, extremely susceptible to low oxygen levels. 19 Free radicals play a critical role in signalling species in many regular physiological processes, but such radicals' excessive production leads to damage biological material. The high levels of ROS in hypoxia caused by the accumulation of reducing equivalents in the mitochondrial electron transport system. 20 ROS's effects can be observed mainly in specific tissues, such as the brain because it uses approximately 1/5 of the basal oxygen. Hemoglobin is an oxygen carrier in red blood cells. Any interferences in hemoglobin's performance with oxygen transport lead to hypoxia conditions. Then, lack of oxygen in the environment, followed by mitochondrial low oxygen partial pressure, causes cell death because of inadequate energy. Available research studies illustrate that using NaF induces circulatory hypoxia, increasing the blood histamine content and decreasing the oxygen-carrying capacity. 21 In the hemic hypoxia model induced to the mice, NaNO 2 reduces the blood's oxygen-carrying capacity by converting hemoglobin to methemoglobin and breaking the respiratory chain, preventing the cell from using oxygen to produce energy. 22, 23 Herein, this experimental in vivo investigation, which was designed and simulated based on the RECOVERY study, demonstrated an excellent protective effect for 10 days of dexamethasone treatment against hypoxia, especially in asphyctic and hemic models. These findings may reveal one of the primary mechanisms for dexamethasone's clinical benefits against COVID-19. More interesting, in addition to promising outcomes of dexamethasone, using 30 mg/kg of propranolol as the positive control drug in this study illustrated a very considerable anti-hypoxic effect even much better than dexamethasone in all models (Figure 1) . The propranolol is a nonselective β-blocker agent that has indicated fantastic activities such as an increase of oxygen utilisation during hypoxia, 24 Epidemiology, patterns of care, and mortality for patients with acute respiratory distress syndrome in intensive care units in 50 countries Acute respiratory distress in adults Dexamethasone treatment for the acute respiratory distress syndrome: a multicentre, randomised controlled trial Adjunctive glucocorticoid therapy in patients with septic shock Hydrocortisone plus fludrocortisone for adults with septic shock Dexamethasone in hospitalized patients with covid-19 -preliminary report Estimates of the severity of coronavirus disease 2019: a model-based analysis Use of Laboratory A. 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