G6PD deficiency-does it alter the course of COVID-19 infections?

Despite the existence of well-founded data around the relationship between reactive oxygen species (ROS) and glucose-6-phosphate dehydrogenase (G6PD), current research around G6PD-deficient patients with viral infections, and limitations as a result of their condition, are inadequate. Here, we analyze existing data around immunological risks, complications, and consequences of this disease, particularly in relation to COVID-19 infections and treatment. The relationship between G6PD deficiency and elevated ROS leading to increased viral load suggests that these patients may confer heightened infectivity. Additionally, worsened prognoses and more severe complications of infection may be realized in class I G6PD-deficient individuals. Though more research is demanded on the topic, preliminary studies suggest that antioxidative therapy which reduces ROS levels in these patients could prove beneficial in the treatment of viral infections in G6PD-deficient individuals.

The Possible Role of Glucose-6-Phosphate Dehydrogenase in the SARS-CoV-2 Infection.

Glucose-6-phosphate dehydrogenase (G6PD) is the second rate-limiting enzyme of the pentose phosphate pathway. This enzyme is present in the cytoplasm of all mammalian cells, and its activity is essential for an adequate functioning of the antioxidant system and for the response of innate immunity. It is responsible for the production of nicotinamide adenine dinucleotide phosphate (NADPH), the first redox equivalent, in the pentose phosphate pathway. Viral infections such as SARS-CoV-2 may induce the Warburg effect with an increase in anaerobic glycolysis and production of lactate. This condition ensures the success of viral replication and production of the virion. Therefore, the activity of G6PD may be increased in COVID-19 patients raising the level of the NADPH, which is needed for the enzymatic and non-enzymatic antioxidant systems that counteract the oxidative stress caused by the cytokine storm. G6PD deficiency affects approximately 350-400 million people worldwide; therefore, it is one of the most prevalent diseases related to enzymatic deficiency worldwide. In G6PD-deficient patients exposed to SARS-CoV-2, the amount of NADPH is reduced, increasing the susceptibility for viral infection. There is loss of the redox homeostasis in them, resulting in severe pneumonia and fatal outcomes.

G6PD deficiency: imbalance of functional dichotomy contributing to the severity of COVID-19.

Human COVID-19 has affected more than 491 million people worldwide. It has caused over 6.1 million deaths and has especially perpetrated a high number of casualties among the elderly and those with comorbid illnesses. COVID-19 triggers a pro-oxidant response, leading to the production of reactive oxygen species (ROS) as a common innate defense mechanism. However, ROS are regulated by a key enzyme called G6PD via the production of reduced nicotinamide adenine dinucleotide phosphate (NADPH), which controls the generation and removal of ROS in a tissue-specific manner. Therefore, a deficiency of G6PD can lead to the dysregulation of ROS, which causes a severe inflammatory response in COVID-19 patients. This report highlights the G6PD dichotomy in the regulation of ROS and inflammatory responses, as well as its deficiency in severity among COVID-19 patients.

COVID-19 in G6PD-deficient Patients, Oxidative Stress, and Neuropathology.

Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme that regulates energy metabolism mainly through the pentose phosphate pathway (PPP). It is well known that this enzyme participates in the antioxidant/oxidant balance via the synthesis of energy-rich molecules: nicotinamide adenine dinucleotide phosphate reduced (NADPH), the reduced form of flavin adenine dinucleotide (FADH) and glutathione (GSH), controlling reactive oxygen species generation. Coronavirus disease 19 (COVID-19), induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a public health problem that has caused approximately 4.5 million deaths since December 2019. Concerning the role of G6PD in COVID-19 development, it is known from the existing literature that G6PD-deficient patients infected with SARS-CoV-2 are more susceptible to thrombosis and hemolysis, suggesting that G6PD deficiency facilitates infection by SARS-CoV-2. Concerning G6PD and neuropathology, it has been observed that deficiency of this enzyme is also present with an increase in oxidative markers. Concerning the role of G6PD and the neurological manifestations of COVID-19, it has been reported that the enzymatic deficiency in patients infected with SARSCoV- 2 exacerbates the disease, and, in some clinical reports, an increase in hemolysis and thrombosis was observed when patients were treated with hydroxychloroquine (OH-CQ), a drug with oxidative properties. In the present work, we summarize the evidence of the role of G6PD in COVID- 19 and its possible role in the generation of oxidative stress and glucose metabolism deficits, and inflammation present in this respiratory disease and its progression including neurological manifestations.

Management of children with glucose-6-phosphate dehydrogenase deficiency presenting with acute haemolytic crisis during the SARs-COV-2 pandemic.

BACKGROUND AND OBJECTIVES: Shortage of blood during the severe acute respiratory syndrome-COV-2 (SARs-COV-2) pandemic impacted transfusion practice. The primary aim of the study is to assess management of acute haemolytic crisis (AHC) in glucose-6-phosphate dehydrogenase(G6PD)- deficient children during SARs-COV-2 pandemic, and then to assess blood donation situation and the role of telemedicine in management. METHODS: Assessment of G6PD-deficient children attending the Emergency Department (ER) with AHC from 1 March 2020 for 5 months in comparison to same period in the previous 2 years, in three paediatric haematology centres. AHC cases presenting with infection were tested for SARs-COV-2 using RT-PCR. Children with Hb (50-65 g/L) and who were not transfused, were followed up using telemedicine with Hb re-checked in 24 h. RESULTS: A 45% drop in ER visits due to G6PD deficiency-related AHC during SARs-COV-2 pandemic in comparison to the previous 2 years was observed. 10% of patients presented with fever and all tested negative for COVID-19 by RT-PCR. 33% of patients had Hb < 50 g/L and were all transfused. 50% had Hb between 50 and 65 g/L, half of them (n = 49) did not receive transfusion and only two patients (4%) required transfusion upon follow up. A restrictive transfusion strategy was adopted and one of the reasons was a 39% drop in blood donation in participating centres. CONCLUSION: Fewer G6PD-deficient children with AHC visited the ER during SARs-COV-2 and most tolerated lower Hb levels. Telemedicine was an efficient tool to support their families. A restrictive transfusion strategy was clear in this study.

G6PD distribution in sub-Saharan Africa and potential risks of using chloroquine/hydroxychloroquine based treatments for COVID-19.

Chloroquine/hydroxychloroquine have been proposed as potential treatments for COVID-19. These drugs have warning labels for use in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Analysis of whole genome sequence data of 458 individuals from sub-Saharan Africa showed significant G6PD variation across the continent. We identified nine variants, of which four are potentially deleterious to G6PD function, and one (rs1050828) that is known to cause G6PD deficiency. We supplemented data for the rs1050828 variant with genotype array data from over 11,000 Africans. Although this variant is common in Africans overall, large allele frequency differences exist between sub-populations. African sub-populations in the same country can show significant differences in allele frequency (e.g. 16.0% in Tsonga vs 0.8% in Xhosa, both in South Africa, p = 2.4 × 10-3). The high prevalence of variants in the G6PD gene found in this analysis suggests that it may be a significant interaction factor in clinical trials of chloroquine and hydroxychloroquine for treatment of COVID-19 in Africans.

Reference and point-of-care testing for G6PD deficiency: Blood disorder interference, contrived specimens, and fingerstick equivalence and precision.

Certain clinical indications and treatments such as the use of rasburicase in cancer therapy and 8-aminoquinolines for Plasmodium vivax malaria treatment would benefit from a point-of-care test for glucose-6-phosphate dehydrogenase (G6PD) deficiency. Three studies were conducted to evaluate the performance of one such test: the STANDARD™ G6PD Test (SD BIOSENSOR, South Korea). First, biological interference on the test performance was evaluated in specimens with common blood disorders, including high white blood cell (WBC) counts. Second, the test precision on fingerstick specimens was evaluated against five individuals of each, deficient, intermediate, and normal G6PD activity status. Third, clinical performance of the test was evaluated at three point-of-care settings in the United States. The test performed equivalently to the reference assay in specimens with common blood disorders. High WBC count blood samples resulted in overestimation of G6PD activity in both the reference assay and the STANDARD G6PD Test. The STANDARD G6PD Test showed good precision on multiple fingerstick specimens from the same individual. The same G6PD threshold values (U/g Hb) were applied for a semiquantitative interpretation for fingerstick- and venous-derived results. The sensitivity/specificity values (95% confidence intervals) for the test for G6PD deficiency were 100 (92.3-100.0)/97 (95.2-98.2) and 100 (95.7-100.0)/97.4 (95.7-98.5) for venous and capillary specimens, respectively. The same values for females with intermediate (> 30% to ≤ 70%) G6PD activity were 94.1 (71.3-99.9)/88.2 (83.9-91.7) and 82.4 (56.6-96.2)/87.6(83.3-91.2) for venous and capillary specimens, respectively. The STANDARD G6PD Test enables point-of-care testing for G6PD deficiency.

Glucose-6-phosphate dehydrogenase inhibitor for treatment of severe COVID-19: Polydatin.

The COVID-19 pandemic as the largest global public health crisis is now considered as an emergency at the World Health Organization (WHO). As there is no specific therapy for SARS-CoV-2 infection at present and also because of the long time it takes to discover a new drug and the urgent need to respond urgently to a pandemic infection. Perhaps the best way right now is to find an FDA-approved drug to treat this infection. Oxidative stress and inflammation play a vital role in the progression of tissue injury in COVID-19 patients; furthermore, the G6PD activation is related to increased oxidative inflammation in acute pulmonary injury. In this regard, we propose a new insight that may be a good strategy for this urgency. Exploiting G6PD through inhibiting G6PD activity by modifying redox balance, metabolic switching and protein-protein interactions can be proposed as a new approach to improving patients in severe stage of COVID 19 through various mechanisms. Polydatin is isolated from many plants such as Polygonum, peanuts, grapes, red wines and many daily diets that can be used in severe stage of COVID-19 as a G6PD inhibitor. Furthermore, polydatin possesses various biological activities such as anti-inflammatory, antioxidant, immunoregulatory, nephroprotective, hepatoprotective, anti-arrhythmic and anti-tumor. Our hypothesis is that the consumption of antioxidants such as Polydatin (a glucoside of resveratrol) as a complementary therapeutic approach may be effective in reducing oxidative stress and inflammation in patients with COVID-19.

COVID-19 may enhance risk of thrombosis and hemolysis in the G6PD deficient patients.

COVID-19 has become a major public health problem since December, 2019 and no highly effective drug has been found until now. Numbers of infected people and deaths by COVID-19 are increasing every day worldwide, therefore self-isolation and protection are highly recommended to prevent the spread of the virus and especially to protect major risk groups such as the elderly population and people with comorbidities including diabetes, hypertension, cancer, cardiovascular diseases and metabolic syndrome. On the other hand, young people without any secondary disease have died by COVID-19 as well. In this study we compared two male patients infected by COVID-19 at the same age and one of them was diagnosed with G6PD deficiency. Both COVID-19 and G6PD deficiency enhance the risk of hemolysis and thrombosis. Serum biochemistry, hemogram and immunological parameters showed that risk of hemolysis and thrombosis may increase in the G6PD deficient patient infected by COVID-19.

Glucose-6-phosphate dehydrogenase deficiency enhances Covid-19 infection in elderly people.

Our understanding of the mechanisms responsible for death of aged people from Covid-19 became one of the major concerns of these days. Glucose-6-phosphate dehydrogenase (G6PD) enhances the normal senescence and accelerates the precocious removal of chronologically young, yet biologically aged cells. Thus, its deficiency is associated with an increase in the cellular oxidative stress. Accumulating evidence showed that oxidative stress has a fundamental role in several age-related diseases. Nowadays, Covid-19 is considered a serious health problem worldwide. The host cellular environment is the key determinant of pathogen Infectivity. Most respiratory viral infections have a strong association with Glucose-6-phosphate dehydrogenase. Unfortunately, this enzyme deficiency markedly decreases with aging what is involved in increasing of the morbidity rate. The aim of this mini review was to shed more light on the role of G6PD deficiency in aged people infected with Covid-19 (Ref. 20). Keywords: GSPD, Covid-19, elderly people.

The potential link between inherited G6PD deficiency, oxidative stress, and vitamin D deficiency and the racial inequities in mortality associated with COVID-19.

There is a marked variation in mortality risk associated with COVID-19 infection in the general population. Low socioeconomic status and other social determinants have been discussed as possible causes for the higher burden in African American communities compared with white communities. Beyond the social determinants, the biochemical mechanism that predisposes individual subjects or communities to the development of excess and serious complications associated with COVID-19 infection is not clear. Virus infection triggers massive ROS production and oxidative damage. Glutathione (GSH) is essential and protects the body from the harmful effects of oxidative damage from excess reactive oxygen radicals. GSH is also required to maintain the VD-metabolism genes and circulating levels of 25-hydroxyvitamin D (25(OH)VD). Glucose-6-phosphate dehydrogenase (G6PD) is necessary to prevent the exhaustion and depletion of cellular GSH. X-linked genetic G6PD deficiency is common in the AA population and predominantly in males. Acquired deficiency of G6PD has been widely reported in subjects with conditions of obesity and diabetes. This suggests that individuals with G6PD deficiency are vulnerable to excess oxidative stress and at a higher risk for inadequacy or deficiency of 25(OH)VD, leaving the body unable to protect its 'oxidative immune-metabolic' physiological functions from the insults of COVID-19. An association between subclinical interstitial lung disease with 25(OH)VD deficiencies and GSH deficiencies has been previously reported. We hypothesize that the overproduction of ROS and excess oxidative damage is responsible for the impaired immunity, secretion of the cytokine storm, and onset of pulmonary dysfunction in response to the COVID-19 infection. The co-optimization of impaired glutathione redox status and excess 25(OH)VD deficiencies has the potential to reduce oxidative stress, boost immunity, and reduce the adverse clinical effects of COVID-19 infection in the AA population.

G6PD deficiency, redox homeostasis, and viral infections: implications for SARS-CoV-2 (COVID-19).

The COVID-19 pandemic has so far affected more than 45 million people and has caused over 1 million deaths worldwide. Infection with SARS-CoV-2, the pathogenic agent, which is associated with an imbalanced redox status, causes hyperinflammation and a cytokine storm, leading to cell death. Glucose-6-phosphate dehydrogenase (G6PD) deficient individuals may experience a hemolytic crisis after being exposed to oxidants or infection. Individuals with G6PD deficiency are more susceptible to coronavirus infection than individuals with normally functioning G6PD. An altered immune response to viral infections is found in individuals with G6PD deficiency. Evidence indicates that G6PD deficiency is a predisposing factor of COVID-19.