The Controversial Role of Glucose-6-Phosphate Dehydrogenase Deficiency on Cardiovascular Disease: A Narrative Review.

Cardiovascular disorders (CVD) are highly prevalent and the leading cause of death worldwide. Atherosclerosis is responsible for most cases of CVD. The plaque formation and subsequent thrombosis in atherosclerosis constitute an ongoing process that is influenced by numerous risk factors such as hypertension, diabetes, dyslipidemia, obesity, smoking, inflammation, and sedentary lifestyle. Among the various risk and protective factors, the role of glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common inborn enzyme disorder across populations, is still debated. For decades, it has been considered a protective factor against the development of CVD. However, in the recent years, growing scientific evidence has suggested that this inherited condition may act as a CVD risk factor. The role of G6PD deficiency in the atherogenic process has been investigated using in vitro or ex vivo cellular models, animal models, and epidemiological studies in human cohorts of variable size and across different ethnic groups, with conflicting results. In this review, the impact of G6PD deficiency on CVD was critically reconsidered, taking into account the most recent acquisitions on molecular and biochemical mechanisms, namely, antioxidative mechanisms, glutathione recycling, and nitric oxide production, as well as their mutual interactions, which may be impaired by the enzyme defect in the context of the pentose phosphate pathway. Overall, current evidence supports the notion that G6PD downregulation may favor the onset and evolution of atheroma in subjects at risk of CVD. Given the relatively high frequency of this enzyme deficiency in several regions of the world, this finding might be of practical importance to tailor surveillance guidelines and facilitate risk stratification.

Glucose-6-phosphate dehydrogenase deficiency and hydroxychloroquine in the COVID-19 era: a mini review.

The coronavirus disease 2019 (COVID-19) is until today a global health emergency. In an immense effort, effective drugs against COVID-19 are searched and intensive researches on possible repurposing of antiviral agents are performed. Since chloroquine (CQ) and hydroxychloroquine (HCQ) have shown in vitro anti- COVID-19 activities, the potential effect of CQ/HCQ to treat and/or prevent COVID-19 infection has caused global attention. However, concern regarding possible hemolysis in G6PD-deficient COVID-19 patients exists and for this reason, the association between HCQ and G6PD deficiency (G6PDD) is back in the limelight. This study aims to answer the question raised by Mastroianni et al. "Hydroxychloroquine: Culprit or Innocent Bystander in G6PD-Deficient Patients with COVID-19?", reporting all cases of HCQ in G6PD deficient COVID-19 patients published on PubMed (pubmed.ncbi.nlm.nih.gov), in addition to the Mastroianni's patient. In our opinion, after an accurate revision of these cases and responding the question raised by Mastroianni et al., we believe that it is difficult to reach a final verdict about the definitive role of HCQ in these patients. The COVID-19 pandemic has reopened attention on HCQ use and G6PDD. G6PD status is extremely important in modulating the level of reactive oxygen species and many cellular immune responses such as enhanced production of the pro-inflammatory cytokine and inflammasome activation. Since these processes are involved in COVID-19 infection, acute hemolytic anemia, a severe complication of the G6PDD, can occur in these patients. In this context, the role of HCQ, usually effective, safe, and well tolerated in G6PD deficient patients, must be redefined in these patients with COVID-19.As consequence, answering the question: "Hydroxychloroquine: Culprit or Innocent Bystander in G6PD-Deficient Patients with COVID-19?", we state that it is risky to believe that HCQ may be an "innocent bystander" in G6PD-deficient COVID-19 patients.

G6PD deficiency and severity of COVID19 pneumonia and acute respiratory distress syndrome: tip of the iceberg?

The severe pneumonia caused by the human coronavirus (hCoV)-SARS-CoV-2 has inflicted heavy casualties, especially among the elderly and those with co-morbid illnesses irrespective of their age. The high mortality in African-Americans and males, in general, raises the concern for a possible X-linked mediated process that could affect the viral pathogenesis and the immune system. We hypothesized that G6PD, the most common X-linked enzyme deficiency, associated with redox status, may have a role in severity of pneumonia. Retrospective chart review was performed in hospitalized patients with COVID19 pneumonia needing supplemental oxygen. A total of 17 patients were evaluated: six with G6PD deficiency (G6PDd) and 11 with normal levels. The two groups (normal and G6PDd) were comparable in terms of age, sex, co-morbidities, and laboratory parameters-LDH, IL-6, CRP, and ferritin, respectively. Thirteen patients needed ventilatory support ; 8 in the normal group and 5 in the G6PDd group (72% vs.83%). The main differences indicating increasing severity in normal vs. G6PDd groups included G6PD levels (12.2 vs. 5.6, P = 0.0002), PaO2/FiO2 ratio (159 vs. 108, P = 0.05), days on mechanical ventilation (10.25 vs. 21 days P = 0.04), hemoglobin level (10 vs. 8.1 P = 0.03), and hematocrit (32 vs. 26 P = 0.015). Only one patient with G6PDd died; 16 were discharged home. Our clinical series ascribes a possible biological role for G6PDd in SARS-CoV2 viral proliferation. It is imperative that further studies are performed to understand the interplay between the viral and host factors in G6PDd that may lead to disparity in outcomes. KEY POINTS: • COVID19 studies show higher mortality in men, due to severe pneumonia and ARDS, indicating possible X-linked mediated differences • G6PD, the most common X-linked enzymopathy, highly prevalent in African Americans and Italians, maintains redox homeostasis. • Preclinical studies using G6PD deficient (G6PDd) cells infected with human coronavirus (hCoV), show impaired cellular responses, viral proliferation and worsening oxidative damage. • Retrospective chart review in hospitalized patients with COVID19 pneumonia needing supplemental oxygen shows differences between the two groups (Normal and G6PDd) in hematological indices; the G6PDdgroup demonstrated prolonged PaO2/FiO2 ratio, and longer days on mechanical ventilation indicating the severity of the pneumonia.

The Elderly with Glucose-6-Phosphate Dehydrogenase Deficiency are More Susceptible to Cardiovascular Disease.

AIM: Recent studies suggest that glucose-6-phosphate dehydrogenase (G6PD) deficiency, a genetically inherited condition causing hemolytic anemia, may be a risk factor for cardiovascular disease (CVD). We aimed to perform a retrospective case-control study in Sardinia taking advantage from clinical records of patients undergoing upper digestive endoscopy and screened for H. pylori infection. METHODS: A total of 9,604 patients with a known G6PD status and a complete clinical history, encompassing CVD, and leading CVD risk factors, including H. pylori infection, undergoing upper endoscopy between 2002 and 2017 were enrolled in this study. RESULTS: Multivariate logistic regression analysis confirmed an increased CVD risk in subjects with G6PD deficiency [odd ratio (OR), 3.24; 95% confidence interval (CI) 2.44-4.30] after adjusting for potential confounders and effect modifiers, including H. pylori infection. Cardiovascular risk was similar in subjects with and without G6PD deficiency before age 60 (OR, 1.26; 95% CI 0.78-2.04, P=0.562), whereas it increased after age 60 in the former group (OR, 3.05; 95% CI 2.22-4.19, P＜0.0001) especially in males (OR 3.67; 95% CI 2.19-6.14) compared with females (OR, 2.96; 95% CI 1.89-4.64) by sex-specific logistic regression analysis. CONCLUSION: The risk of CVD was greater in G6PD-deficient subjects after age 60, both in males and females, than those with normal enzyme activity, after adjusting for conventional CVD risk factors and H. pylori infection. The reduction of important protective mechanisms against oxidative stress in the elderly might explain the study findings.

Aspirin Therapy in Cardiovascular Disease with Glucose-6-Phosphate Dehydrogenase Deficiency, Safe or Not?

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect, which may present as acute hemolysis, neonatal jaundice, or chronic hemolysis. Ingestion of fava beans, as well as infection and certain drugs, are the most typical causes of acute hemolysis in people with G6PD deficiency. Aspirin, the cornerstone in current therapies for the prevention of cardiovascular disease (CVD), is occasionally reported to induce acute hemolysis in G6PD-deficient individuals. G6PD deficiency is typically asymptomatic and many CVD patients with this enzyme defect start to take long-term aspirin therapy without G6PD activity examination; however, no consensus on the safety of aspirin in this population has been reached. A few studies have reported on this issue and produced contradictory results. In this review, we discuss the possible mechanisms of aspirin-induced hemolysis, and summarize clinical evidence regarding the safety of aspirin in subjects with G6PD deficiency.

Glucose-6-Phosphate Dehydrogenase Deficiency and the Benefits of Early Screening.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common enzymopathy worldwide, is an insufficient amount of the G6PD enzyme, which is vital to the protection of the erythrocyte. Deficient enzyme levels lead to oxidative damage, hemolysis, and resultant severe hyperbilirubinemia. If not promptly recognized and treated, G6PD deficiency can potentially lead to bilirubin-induced neurologic dysfunction, acute bilirubin encephalopathy, and kernicterus. Glucose-6-phosphate dehydrogenase deficiency is one of the three most common causes for pathologic hyperbilirubinemia. A change in migration patterns and intercultural marriages have created an increased incidence of G6PD deficiency in the United States. Currently, there is no universally mandated metabolic screening or clinical risk assessment tool for G6PD deficiency in the United States. Mandatory universal screening for G6PD deficiency, which includes surveillance and hospital-based risk assessment tools, can identify the at-risk infant and foster early identification, diagnosis, and treatment to eliminate neurotoxicity.

Management of Athletes With G6PD Deficiency: Does Missing an Enzyme Mean Missing More Games?

CONTEXT: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is likely the most prevalent enzyme deficiency on the planet, with an estimated 4.9% of people, or approximately 330 million individuals, across the globe affected by the disease. In the United States, 4% to 7% of the population is likely affected, but each year our nation's major sport leagues become more international. It is important for medical professionals who treat athletes to understand how this genetic condition can affect the athletes we are working with, especially because exercise in itself results in oxidative stress. EVIDENCE ACQUISITION: PubMed was searched for relevant articles published from 1980 to 2018. The search terms G6PD, athletes, military, and sports were used. STUDY DESIGN: Clinical review. LEVEL OF EVIDENCE: Level 4. RESULTS: Though some case reports suggest a potential impact on athlete safety and performance, controlled studies demonstrate limited impact of exercise on oxidative stress in G6PD-deficient individuals. The care of athletes with G6PD deficiency does not drastically differ from the care of athletes without this condition. Most of the medications and supplements that are regularly given to athletes should not negatively affect their health. CONCLUSION: Although the care of athletes with G6PD deficiency is for the most part no different from the care of other athletes, there are certain situations (visiting areas where malaria is endemic) and medications for which it is important to recognize how your management should change. G6PD deficiency is not regularly screened for but could be considered if an athlete has known sickle cell disease or when traveling to areas where malaria is prevalent. Expanding our knowledge of G6PD deficiency will allow for better care of athletes.

G6PD deficiency: An update.

Although glucose-6-phosphate dehydrogenase (G6PD) deficiency is less known in Western countries than in the Middle East and Africa, global migration and immigration are bringing ethnic groups with the highest incidence of this inherited genetic disorder into the US healthcare system. The G6PD enzyme is critical to protecting erythrocytes against oxidative stress, and deficiency may lead to hemolysis in the presence of certain environmental factors such as infection and some medications and foods. Neonatal jaundice, favism, and hemolysis are associated with exposure to increased oxidative stressors in patients with G6PD deficiency. By recognizing the potential for G6PD deficiency, clinicians can screen for the disorder and teach affected patients how to avoid triggers that result in harmful clinical manifestations.

The Redox Role of G6PD in Cell Growth, Cell Death, and Cancer.

The generation of reducing equivalent NADPH via glucose-6-phosphate dehydrogenase (G6PD) is critical for the maintenance of redox homeostasis and reductive biosynthesis in cells. NADPH also plays key roles in cellular processes mediated by redox signaling. Insufficient G6PD activity predisposes cells to growth retardation and demise. Severely lacking G6PD impairs embryonic development and delays organismal growth. Altered G6PD activity is associated with pathophysiology, such as autophagy, insulin resistance, infection, inflammation, as well as diabetes and hypertension. Aberrant activation of G6PD leads to enhanced cell proliferation and adaptation in many types of cancers. The present review aims to update the existing knowledge concerning G6PD and emphasizes how G6PD modulates redox signaling and affects cell survival and demise, particularly in diseases such as cancer. Exploiting G6PD as a potential drug target against cancer is also discussed.