Erythrocyte Glucose-6-phosphate Dehydrogenase Activity Research Articles

Glifosatın glukoz-6-fosfat dehidrogenaz enzim aktivitesi üzerindeki etkisinin in vitro koşullarda değerlendirilmesi

Purpose: The aim of this study was to investigate in vitro effect of glyphosate on Glucose 6-phosphate dehydrogenase (G6PD) enzyme activity.
 Materials and Methods: In terms of G6PD enzyme deficiency, samples taken from healthy and enzyme deficient male individuals were studied. After the hemolysates were prepared from blood sample, G6PD enyzme activities were determined by the modified Beutler method. Then, the effects of different concentrations (5.3x10-3, 5.3x10-4, 5.3x10-5, 5.3x10-6 mmol/mL) of glyphosate on G6PD activity were evaluated in normal and mutant enzymes. In addition, the in vitro effect of the antioxidant N-acetylcysteine (NAC) on the enzyme was investigated in the presence of glyphosate and without glyphosate.
 Results: While the result of normal erythrocyte G6PD activity was 12U/g for the individual, the result for the individual with enzyme deficiency was 2.5U/g Hb. The glyphosate’s maximum activity loss in the G6PD enzyme was observed in the 60th minute incubation. The highest inhibition was observed at 5.3x10-3 mmol/mL glyphosate. 4.7x10-7 mmol/mL N-Acetylcysteine partially increased the inhibition of glyphosate in the G6PD enzyme in healthy individuals, but had no effect on mutant G6PD.
 Conclusion: In humans, it is predicted that glyphosate affects G6PD enzyme activity in vitro and is an interference agent in the experimental process. In case of contamination, studies on limits of glyphosate that will not cause harmful effects in humans should be continued.

Effect of combined G6PD deficiency and diabetes on protein oxidation and lipid peroxidation

BackgroundOxidative Stress, an imbalance in the pro-oxidant/antioxidant homeostasis, occurs in many physiological and non-physiological processes and several human diseases, including diabetes mellitus (DM) and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Since the incidence of G6PD deficiency in Jordan and many parts of the world is high, this study aimed to measure the effect of G6PD deficiency on the oxidative markers and the antioxidant glutathione (GSH) in diabetic and non-diabetic individuals.MethodsWhole blood G6PD deficiency was screened by the fluorescent spot method, and erythrocyte G6PD activity was determined using a quantitative assay. Since protein carbonyl (PC) and malondialdehyde (MDA) are the most widely measured markers for protein and lipid oxidation, respectively, plasma PC and MDA, in addition to blood GSH were determined by spectrophotometric assays, as biomarkers of oxidative stress.ResultsThe incidence of G6PD deficiency among the diabetic subjects was 15%. PC level in patients with diabetes and in G6PD-deficient subjects was 5.5 to 6-fold higher than in non-diabetic subjects with sufficient G6PD levels (p<0.001). This fold increase was doubled in diabetic patients with G6PD deficiency (p<0.001). Furthermore, the MDA level was significantly increased by 28-41% in G6PD-deficient, diabetics with sufficient G6PD, and diabetics with G6PD deficiency compared to MDA level in non-diabetic with sufficient G6PD. On the other hand, GSH was significantly reduced to half in G6PD-deficient subjects and in diabetics with G6PD-deficiency.ConclusionsThe results showed that diabetes and G6PD deficiency increased protein oxidation and lipid peroxidation. However, the combination of both disorders has an additive effect only on protein oxidation. On the other hand, GSH level is only reduced in G6PD deficiency. In addition, diabetes and G6PD deficiency appear to be genetically linked since the incidence of G6PD deficiency among people with diabetes is more than the general population.

Brief Report: Hydroxychloroquine does not induce hemolytic anemia or organ damage in a "humanized" G6PD A- mouse model.

BackgroundHydroxychloroquine (HCQ) is widely used in the treatment of malaria, rheumatologic disease such as lupus, and most recently, COVID-19. These uses raise concerns about its safe use in the setting of glucose-6-phosphate dehydrogenase (G6PD) deficiency, especially as 11% of African American men carry the G6PD A- variant. However, limited data exist regarding the safety of HCQ in this population.Study design and methodsRecently, we created a novel “humanized” mouse model containing the G6PD deficiency A- variant (Val68Met) using CRISPR technology. We tested the effects of high-dose HCQ administration over 5 days on hemolysis in our novel G6PD A- mice. In addition to standard hematologic parameters including plasma hemoglobin, erythrocyte methemoglobin, and reticulocytes, hepatic and renal function were assessed after HCQ.ResultsResidual erythrocyte G6PD activity in G6PD A- mice was ~6% compared to wild-type (WT) littermates. Importantly, we found no evidence of clinically significant intravascular hemolysis, methemoglobinemia, or organ damage in response to high-dose HCQ.ConclusionsThough the effects of high doses over prolonged periods was not assessed, this study provides early, novel safety data of the use of HCQ in the setting of G6PD deficiency secondary to G6PD A-. In addition to novel safety data for HCQ, to our knowledge, we are the first to present the creation of a “humanized” murine model of G6PD deficiency.

Glucose-6-phosphate dehydrogenase deficiency in Tunisian jaundiced neonates.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzymopathy worldwide associated with hemolysis as well as neonatal jaundice, kernicterus, and even death. The goal of this study is to determinate the prevalence of G6PD deficiency in icteric neonates and to investigate its biochemical, hematological and molecular characteristics. This cross sectional study was carried out on 154 icteric newborns admitted to the Bechir Hamza Children's Hospital in Tunisia. Laboratory evaluations included complete blood count, total serum bilirubin level (TSB), and erythrocyte G6PD activity. The G6PD activity was determined using a quantitative assay, which allowed us to divide the total population into two groups: normal and deficient population. The common G6PD Tunisian mutations (GdA - and GdMed) were determined using the amplification refractory mutation system (ARMS-PCR) method. The prevalence of G6PD deficiency among total population (154 icteric newborns) was 18.83%. Male neonates showed a higher incidence of G6PD deficiency of 11.03% compared to females (7.79%). There was no statistical difference between the two groups (normal and deficient), in relation to the sex, peak TSB level, age at peak TSB, hemoglobin level, and hematocrit. However, there was a significant difference in gestational age. In the deficient group, 48.28% neonates presented the peak TSB level between 3 to 7 days and 55% of the cases show a peak TSB level greater than 250 μmol/L. The G6PD G202A variant was found in 41.37% of cases. This study shows a higher prevalence of G6PD deficiency in icteric newborns of Tunisia (18.83%). This emphasizes the necessity of neonatal screening for G6PD deficiency to prevent the exposure of these newborns to known hemolytic agents and, subsequently, to prevent kernicterus or other serious complications.

Erythrocyte glucose-6-phosphate dehydrogenase activity and risk of gestational diabetes.

Glucose-6-phosphate dehydrogenase (G6PD) is the regulating enzyme in the pentose phosphate pathway. A link between the activity of G6PD and diabetes mellitus has previously been reported. The association of G6PD activity with the pathogenesis of gestational diabetes mellitus (GDM) has not yet been investigated. The aim of the present study was to investigate the association of erythrocyte G6PD activity with major characteristics of GDM. This case-control study was conducted at Hafez Hospital, Shiraz University of Medical Sciences, Shiraz, Iran from March to November 2017. Eighty-four age-matched pregnant women including GDM (n = 33), impaired glucose tolerance (IGT; n = 7), and normal glucose tolerance (NGT; n = 44) subjects were enrolled in this study. The levels of erythrocyte G6PD activity, fasting plasma glucose (FPG), insulin, malondialdehyde (MDA), and ferric reducing power (FRAP) of serum were measured. The level of homeostasis model for the assessment of insulin resistance (HOMA-IR) was calculated. The data were analyzed using SPSS software. P < 0.05 was considered statistically significant. The values of FPG, insulin, HOMA-IR, G6PD activity, and FRAP were significantly higher in GDM patients compared to NGT subjects. G6PD activity was correlated with FPG ((r = 0.224; P = 0.041). Binary logistic regression analysis revealed independent association of body mass index >25.88 [OR = 3.23, 95% CI 1.071-9.75, P = 0.037], HOMA- IR >2.33 [OR = 7.15, 95% CI 2.26-22.56, P < 0.001], and G6PD activity>21.17U/g Hb [OR = 4.63, 95% CI 1.49-14.38, P = 0.008] with an increased risk of GDM. No significant change was observed among serum MDA levels in the three groups. The findings demonstrate that increased G6PD activity is positively associated with the risk of GDM.

Erythrocyte G6PD activity and GSH level as risk factors for vascular complications among type 2 diabetics in Osogbo, Nigeria

ABSTRACTBackground: Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the oxidation of glucose-6-phosphate (G6P) to produce nicotine-adenosine-dinucleotide phosphate coenzyme (NADPH), a major defense against oxidative damage in erythrocytes. This study aims at evaluating enzymatic G6PD activity and erythrocyte glutathione (eGSH) as a biomarker of vascular complications among type 2 diabetics.Methods: Fasting Plasma glucose (FPG), glycated hemoglobin (HbA1c), erythrocyte G6PD (eG6PD) activity and erythrocyte GSH (eGSH) level were determined along with measured anthropometrics in 120 known type 2 diabetics (comprising 60 diabetics without vascular complications and 60 diabetics with vascular complications) and 50 age and sex matched apparently healthy non diabetes individuals recruited for this study.Results: Result revealed significant reduced eG6PD activity and eGSH levels in type 2 diabetics especially among those with vascular complications as compared to subjects without diabetes, with a slight correlation between eGSH level and eG6PD activity of diabetics with vascular complications.Conclusion: The study, therefore, advocates measurement of G6PD activity and GSH level in type 2 diabetics to properly monitor the progress of the disease.

Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency and Late-stage Age-Related Macular Degeneration

Purpose: Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly in Western Countries. Evidence indicates that Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency, a common genetic abnormality, may protect against ischemic heart and cerebrovascular disease, ocular vascular disorders, and colorectal cancer. This study was undertaken to ascertain whether G6PD deficiency may protect against AMD.Materials and Methods: 79 men with late-stage AMD and 79 male, age-matched cataract controls without AMD were recruited in March-December 2016. Smoking status, clinical history, and drug use were recorded. A blood sample was taken from each participant. Complete blood count, hemoglobin, glucose, creatinine, cholesterol, triglycerides, transaminases, bilirubin, and erythrocyte G6PD activity were measured. Stepwise logistic regression was used to investigate the association between G6PD deficiency and AMD.Results: G6PD deficiency was found in 7 (8.9%) AMD patients and 8 (10.1%) controls, a not statistically significant difference. Stepwise logistic regression disclosed that AMD was significantly associated with increased diastolic blood pressure (OR=1.09, 95% CI=1.03-1.15, P=0.02) and LDL-cholesterol (OR=1.02, 95% CI=1.0001-1.03, P=0.049) and lower values of white blood cell (WBC) count (OR=0.71, 95% CI=0.56-0.88, P=0.02) and aspartate aminotransferase (AST) (OR=0.92, 95% CI=0.85-0.99, P=0.044).Conclusion: Results suggest that G6PD deficiency has no protective effect on nor is a risk factor for AMD. Larger studies are necessary to confirm whether increased diastolic blood pressure and LDL-cholesterol and lower values of WBC count and AST are risk factors for AMD.

Decreased glucose-6-phosphate dehydrogenase activity along with oxidative stress affects visual contrast sensitivity in alcoholics.

To evaluate oxidative stress and glucose-6-phosphate dehydrogenase (G6PD) status of alcoholics and discern their association, if any, with visual contrast sensitivity function. Forty male alcoholic subjects and 36 male non-alcoholic subjects with the same age and nutritional status were enrolled in this study. Serum malondialdehyde (MDA) level and glucose-6-phosphate dehydrogenase (G6PD) activity of erythrocytes were determined by spectrophotometric assay. Contrast sensitivity (CS) function of study subjects was measured using the Rabin Contrast Sensitivity Test (Precision Vision®, La Salle, Illinois, United States). Serum MDA levels were significantly higher (p<0.0001) and erythrocyte G6PD activity was significantly lower (p=0.0026) in alcoholic subjects compared to the controls. CS scores of both eyes were also found to be decreased significantly in alcoholic subjects (both at p<0.0001) compared to control subjects. On the other hand, CS scores of the alcoholic subjects were inversely correlated with the serum MDA level (r=-0.746, p<0.0001) and directly correlated with erythrocyte G6PD activity (r=0.78, p<0.0001). A strong inverse correlation (r=-0.84, p<0.0001) was also observed between serum MDA level and erythrocyte G6PD activity of alcoholic subjects. Reduced G6PD activity and increased serum MDA level might be the key cause of the early visual abnormalities, such as reduced CS function of the alcoholic subjects.

Effect of astaxanthin and aluminum chloride on erythrocyte G6PD and 6PGD enzyme activities in vivo and on erythrocyte G6PD in vitro in rats.

In this study, we investigated the effect of astaxanthin (Ast) and aluminum (Al) on the erythrocyte glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) enzymes activities in vivo and on G6PD enzyme in vitro in rats. For in vitro studies, G6PD enzyme was purified from rat erythrocyte by using 2',5'-ADP-Sepharose 4B affinity gel. The effects of Ast and Al3+ ion were investigated on the purified enzyme. It was determined that Ast increased the enzyme activity, whereas Al3+ inhibited the enzyme activity noncompetitively (IC50 values; 0.679mM, Ki values 1.32mM). For in vivo studies, the rats were divided into the groups: control (Cont.), Al, Ast, and Al+Ast. The last three groups were compared with the control group. In Al group, a significant degree of inhibition was observed in the activity of G6PD and 6PGD enzymes when compared with the control group (P<0.05), whereas there was an increase in the activities of G6PD and 6PGD enzymes in Ast and Al+Ast groups (P<0.05).

Hyperlipidemia-Mediated Increased Advanced Lipoxidation End Products Formation, an Important Factor Associated with Decreased Erythrocyte Glucose-6-Phosphate Dehydrogenase Activity in Mild Nonproliferative Diabetic Retinopathy.

The present study aimed to evaluate the role of hyperlipidemia in increased formation of advanced lipoxidation end products (ALEs) and to evaluate whether there is any relationship between ALEs generation and erythrocyte glucose-6-phosphate dehydrogenase (G6PD) activity in cases of mild nonproliferative diabetic retinopathy (MNPDR). In this study, we enrolled 100 patients with type 2 diabetes and MNPDR, 100 subjects with type 2 diabetes but without retinopathy (DNR) and 90 normal individuals without diabetes as healthy controls (HCs). Erythrocyte nicotinamide dinucleotide phosphate (NADPH), G6PD activity, serum total cholesterol, low- and high-density lipoprotein (LDL, HDL) and triglyceride levels were determined by photometric assay. Serum malondialdehyde (MDA) protein adduct and hexanoyl-lysine (HEL) were measured by an enzyme-linked immunosorbent assay (ELISA). A robust linear relationship was observed between MDA protein adduct and LDL or cholesterol or triglyceride levels, and HEL and LDL or cholesterol or triglyceride levels in subjects with MNPDR (p=0.0001). A significant inverse association was observed between erythrocyte G6PD activity and serum MDA protein adductor HEL levels in subjects with MNPDR (p=0.0001). Hyperlipidemia is an important factor that is associated with increased ALEs formation in persons with MNPDR. Increased ALEs generation was associated with decreased G6PD activity and low NADPH levels in cases of MNPDR, suggesting their detrimental role in the occurrence of early NPDR.

Age-dependent detection of erythrocytes glucose-6-phosphate dehydrogenase and its correlation with oxidative stress

Context: Glucose-6-phosphate dehydrogenase (G6PD) is an important enzyme of hexose monophosphate shunt, involved in the biosynthesis of reduced nicotinamide adenine dinucleotide phosphate hydrogen (NADPH). Objective: This study was designed to investigate age-dependent changes in human erythrocyte G6PD activity. The G6PD activity pattern was correlated with reduced glutathione (GSH) and total antioxidant potential in terms of FRAP (ferric reducing ability of plasma) value. Materials and methods: We analyzed normal, healthy subjects of both sexes between the ages of 20 and 80 years. G6PD activity was determined by Burties method. Results: We observe a significant age-dependent decrease in G6PD activity (p < 0.0001). It was positively correlated with GSH (r = 0.5706) and total antioxidant potential (r = 0.7723) as a function of human age. Discussion and conclusion: Our findings on erythrocyte G6PD and their correlation with GSH and FRAP provide evidence of a higher oxidative stress in old age population.

Hyperglycaemia per se does not affect erythrocyte glucose-6-phosphate dehydrogenase activity in ketosis-prone diabetes

AimPreviously, we described patients with ketosis-prone type 2 diabetes (KPD) and glucose-6-phosphate dehydrogenase (G6PD) deficiency, but no mutation of the G6PD gene. Our present study used two complementary approaches to test whether hyperglycaemia might inhibit G6PD activity: (1) effect of acute hyperglycaemia induced by glucose ramping; and (2) effect of chronic hyperglycaemia using correlation between G6PD activity and HbA1c levels. MethodsIn the first substudy, 16 KPD patients were compared with 11 healthy, non-diabetic control subjects of the same geographical background. Erythrocyte G6PD activity and plasma glucose were assessed at baseline and every 40min during intravenous glucose ramping that allowed maintaining hyperglycaemia for more than 3h. In the second substudy, erythrocyte G6PD activity and HbA1c levels were evaluated in 108 consecutive African patients with either type 2 diabetes or KPD, and a potential correlation sought between the two variables. ResultsThe maximum plasma glucose level after 200min of glucose perfusion was 20.9±3.7mmol/L for patients and 10.7±2.3mmol/L for controls. There was no difference between baseline and repeated G6PD activity levels during acute hyperglycaemia in either KPD patients (P=0.94) or controls (P=0.57), nor was there any significant correlation between residual erythrocyte G6PD activity and HbA1c levels (r=−0.085, P=0.38). ConclusionNeither acute nor chronic hyperglycaemia affects erythrocyte G6PD activity. Thus, hyperglycaemia alone does not explain cases of G6PD deficiency in the absence of gene mutation as described earlier.

Adequate hemodialysis improves anemia by enhancing glucose-6-phosphate dehydrogenase activity in patients with end-stage renal disease.

BackgroundWe conducted this study to determine the erythrocyte glucose-6-phosphate dehydrogenase (G6PD) activity level in patients with end-stage renal disease (ESRD) on maintenance hemodialysis (HD) and to determine the effect of hemodialysis adequacy on G6PD activity levels and its impact on anemia.MethodsEighty-two patients (48 men and 34 women) receiving regular hemodialysis for ESRD through arteriovenous fistulae for at least one year prior to the start of the study were enrolled in this study. G6PD activity levels were measured in all patients and the average Kt/V was used as a parameter of HD adequacy. Patients were divided into two groups according to Kt/V values. Group 1 included 45 patients with Kt/V˃1.2 (adequate HD), and group 2 included 37 patients with Kt/V˃1.2 (inadequate HD). The average hemoglobin level and the weekly dose of an erythropoietin-stimulating agent, epoetin alpha (ESA), for each patient were calculated for one year.ResultsThe mean (SD) erythrocyte G6PD activity for all patients on hemodialysis was 7.64 ± 1.85 U/g Hb. Patients who had received adequate hemodialysis had a significantly higher average erythrocyte G6PD (mean (SD) = 9.2 ± 0.7 U/g Hb) compared to patients who had inadequate hemodialysis (mean (SD) = 5.7 ± 0.7U/g Hb) (P-value <0.005). The mean hemoglobin concentration was significantly higher in patients with adequate hemodialysis compared to those with inadequate hemodialysis.ConclusionOur study demonstrated the beneficial effect of adequate hemodialysis in correcting anemia by enhancing the erythrocyte G6PD activity in patients.

Genetic determinants of glucose-6-phosphate dehydrogenase activity in Kenya.

BackgroundThe relationship between glucose-6-phosphate dehydrogenase (G6PD) deficiency and clinical phenomena such as primaquine-sensitivity and protection from severe malaria remains poorly defined, with past association studies yielding inconsistent and conflicting results. One possibility is that examination of a single genetic variant might underestimate the presence of true effects in the presence of unrecognized functional allelic diversity.MethodsWe systematically examined this possibility in Kenya, conducting a fine-mapping association study of erythrocyte G6PD activity in 1828 Kenyan children across 30 polymorphisms at or around the G6PD locus.ResultsWe demonstrate a strong functional role for c.202G>A (rs1050828), which accounts for the majority of variance in enzyme activity observed (P=1.5×10−200, additive model). Additionally, we identify other common variants that exert smaller, intercorrelated effects independent of c.202G>A, and haplotype analyses suggest that each variant tags one of two haplotype motifs that are opposite in sequence identity and effect direction. We posit that these effects are of biological and possible clinical significance, specifically noting that c.376A>G (rs1050829) augments 202AG heterozygote risk for deficiency trait by two-fold (OR = 2.11 [1.12 - 3.84], P=0.014).ConclusionsOur results suggest that c.202G>A is responsible for the majority of the observed prevalence of G6PD deficiency trait in Kenya, but also identify a novel role for c.376A>G as a genetic modifier which marks a common haplotype that augments the risk conferred to 202AG heterozygotes, suggesting that variation at both loci merits consideration in genetic association studies probing G6PD deficiency-associated clinical phenotypes.

Correlation between oxidative stress and G6PD activity in neonatal jaundice.

Fetal distress represents a pathophysiological condition in which oxygen is not available to the fetus in sufficient quantities. In cases of glucose 6-phosphate dehydrogenase (G6PD) deficiency, under conditions of oxidative stress, the residual G6PD and complimentary antioxidant mechanisms may become insufficient to neutralize the large amounts of ROS and to prevent severe hemolysis. Alteration in the oxidant-antioxidant profile is also known to occur in neonatal jaundice. The study group included 22 neonates presented with fetal distress during labor and 24 neonates with no evidence of fetal distress (control group). Umbilical cord blood samples were taken immediately after delivery, and the following blood tests were carried out after birth and at discharge from the hospital: erythrocyte count, total bilirubin, G6PD activity, and parameters presenting oxidative status [thiobarbituric acid reactive substances (TBARS), NO, O2 (-), H2O2, SOD, CAT, O2 (-)/SOD, and H2O2/CAT]. There were no significant differences in TBARS and NO values among neonates with or without fetal distress. However, the values of O2 (-), H2O2, SOD, O2 (-)/SOD, and H2O2/CAT among neonates born after fetal distress were significantly higher than in neonates without fetal distress (p<0.01). In neonates with fetal distress, the total number of RBCs at delivery was significantly lower, accompanied with higher bilirubin content. Also neonates with fetal distress had lower activity of G6PD and lower CAT activity. Higher values of oxidative stress parameters in newborns delivered after fetal distress do not indicate strictly what occurred first-oxidative stress or basic lower G6PD activity.

Subclinical reduced G6PD activity in rheumatoid arthritis and Sjögren's Syndrome patients: Relation to clinical characteristics, disease activity and metabolic syndrome

Objective. Glucose-6-phosphate dehydrogenase (G6PD) is an important site of metabolic control in the pentose phosphate pathway. The purpose of this study was to investigate the enzyme activity of G6PD in Rheumatoid Arthritis (RA) and Sjögren's Syndrome (SS) patients not known to be deficient in this enzyme. It was also within the scope of the aim to find the relation of G6PD to the presence of metabolic syndrome (MetS) in these patients.Methods. Erythrocyte G6PD activity was evaluated in 40 RA patients, 30 SS patients and in 30 age- and sex-matched control. The clinical characteristics, disease activity score (DAS28), SS disease activity (SSDAI) and damage (SSDDI) indices and presence of MetS of the included patients were analyzed in relation to the enzyme level.Results. The G6PD activity in RA patients (7.72 ± 3.57 U/g Hb) was significantly reduced compared to that in the SS patients (11.55 ± 3.14 U/g Hb) and control (13.23 ± 3.34 U/g Hb) especially those with MetS (4.61 ± 1.84 U/g Hb) (p < 0.001). There was a significant negative correlation of the G6PD activity with the disease duration and DAS28 (p < 0.001).Conclusion. The results of this study, suggest that G6PD not only does not protect against MetS in RA, but may even be considered a risk factor for the development of this disorder. The identification of regulatory tools for G6PD activity may prove promising for treating the associated metabolic disorders and chronic inflammation in RA.

The administration of N-acetylcysteine reduces oxidative stress and regulates glutathione metabolism in the blood cells of workers exposed to lead

Context and objective. The aim of the study was to investigate whether treatment with N-acetylcysteine (NAC) is able to restore erythrocyte glutathione (GSH) content in workers exposed to lead. Additionally, we measured the leukocyte and erythrocyte activities of GSH-related enzymes, such as glutathione reductase (GR), glutathione-S-transferase (GST), and glucose-6-phosphate dehydrogenase (G6PD), and estimated the influence of NAC administration on oxidative stress intensity, which was measured as the lipofuscin (LPS) level in erythrocytes. Methods. The exposed population consisted of 171 healthy males randomly divided into four groups. Workers in the first group (n = 49) were not administered any antioxidants, drugs, vitamins, or dietary supplements, while workers in the remaining groups were treated with NAC at three doses for 12 weeks (1 × 200 mg per day, 2 × 200 mg per day, and 2 × 400 mg per day). All workers continued to work during the study. The blood of all examined workers was drawn two times: at the beginning of the study and after 12 weeks of treatment. Results and conclusion. Blood lead levels decreased significantly in all groups receiving NAC compared to those in baseline. Erythrocyte GSH concentrations were significantly elevated in workers receiving 400 and 800 mg of NAC compared to those in baseline by 5% and 6%, respectively. Erythrocyte G6PD activity was significantly elevated in workers receiving 200, 400, and 800 mg of NAC compared to those in baseline by 24%, 14%, and 14%, respectively. By contrast, there were no significant differences in leukocyte G6PD or leukocyte and erythrocyte glutathione reductase (GR) activities before and after treatment. Leukocyte GST activities decreased significantly after treatment in workers receiving 200 mg of NAC by 34%, while LPS levels decreased significantly in workers receiving 200, 400, and 800 mg of NAC compared to those in baseline by 5%, 15%, and 13%, respectively. In conclusion, NAC decreases oxidative stress in workers exposed to lead via stimulating GSH synthesis.

The effects of chemical and radioactive properties of Tl-201 on human erythrocyte glucose 6-phosphate dehydrogenase activity

The inhibitory effects of thallium-201 ((201)Tl) solution on human erythrocyte glucose 6-phosphate dehydrogenase (G6PD) activity were investigated. For this purpose, erythrocyte G6PD was initially purified 835-fold at a yield of 41.7% using 2',5'-Adenosine diphosphate sepharose 4B affinity gel chromatography. The purification was monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which showed a single band for the final enzyme preparation. The in vitro and in vivo effects of the (201)Tl solution including Tl(+), Fe(+3) and Cu(+2) metals and the in vitro effects of the radiation effect of the (201)Tl solution and non-radioactive Tl(+), Fe(+3) and Cu(+2) metals on human erythrocyte G6PD enzyme were studied. Enzyme activity was determined with the Beutler method at 340 nm using a spectrophotometer. All purification procedures were carried out at +4 degrees C. (201)Tl solution and radiation exposure had inhibitory effects on the enzyme activity. IC(50) value of (201)Tl solution was 36.86 microl ([Tl(+)]: 0.0036 microM, [Cu(+2)]: 0.0116 microM, [Fe(+3)]: 0.0132 microM), of human erythrocytes G6PD. Seven human patients were also used for in vivo studies of (201)Tl solution. Furthermore, non-radioactive Tl(+), Fe(+3) and Cu(+2) were found not to have influenced the enzyme in vitro. Human erythrocyte G6PD activity was inhibited by exposure for up to 10 minutes to 0.057 mCi/kg (201)Tl solution. It was detected in in vitro and in vivo studies that the human erythrocyte G6PD enzyme is inhibited due to the radiation effect of (201)Tl solution.

Glucose‐6‐phosphate dehydrogenase (G6PD) deficiency and senile cataract in a sardinian population, Italy

Abstract Purpose There is still no general agreement on the role of G6PD deficiency in the pathogenesis of cataract. Although G6PD deficiency has been correlated with cataract in some studies, other reports have showed no correlation. The purpose of this study was to determine the prevalence of G6PD deficiency in male patients of Sardinian origin with senile cataract and to compare it with the prevalence rate of G6PD deficiency in the general population of the same area. Methods Erythrocyte G6PD activity was determined using a quantitative assay in 1628 male patients with cataract. The control group consisted of 1646 apparently healthy male patients from the same area described in a former study. Student’s t test was used to determine differences between groups. Results G6PD deficiency was found in 134 (8.2%) patients with cataract and in 120 (7%) control subjects. Differences between cases and controls were not statistically significant (P=0.78). Conclusion The results of this large study suggest that male patients with G6PD deficiency in the Sardinian population do not have a higher risk of developing presenile cataract.

α-Tocopherol supplementation restores the reduction of erythrocyte glucose-6-phosphate dehydrogenase activity induced by forced training

Background Erythrocyte glucose-6-phosphate dehydrogenase (G6PD) activity is closely related to free radical production. α-Tocopherol (alpha-T) is implicated with the reduction of lipid peroxidation. Aim To investigate the effect of training and alpha-T supplementation on the erythrocyte G6PD activity. Methods Blood was obtained from 10 basketball players pre-game (group A), post-game (group B) and after 30 days on alpha-T ( dl-alpha-tocopheryl-acetate, 200 mg 24 h −1 orally) supplementation pre- (group C) and post-training (group D). alpha-T and catecholamines were evaluated with HPLC methods and creatine kinase, lactate dehydrogenase, total antioxidant status (TAS) and G6PD activity with commercial kits. Results TAS was increased in the groups with alpha-T addition (groups C and D). Post-exercise, TAS and G6PD activity were remarkably higher (2.10 ± 0.13 mmol l −1, 7.92 ± 1.5 U g −1 Hb, respectively) in group D than those in group B (0.92 ± 0.10 mmol l −1, 4.8 ± 1.4 U g −1 Hb, p < 0.01, respectively). G6PD activity positively correlated with TAS ( r = 0.64, p < 0.001) in all the studied groups. Conclusions Supplementation with alpha-T may protect G6PD activity from reduction induced by forced training.