Erythrocyte Glucose-6-phosphate Dehydrogenase Research Articles

S3046 Hepatitis B Causing Severe Hemolysis and Multi-Organ Failure in Patients With Undiagnosed G6PD

Introduction: Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic disease. WHO estimates 1.5 million new infections annually. Most people remain asymptomatic; however, some people have acute illness that lasts several weeks, which can at times be complicated with acute liver failure. Glucose-6-phosphate dehydrogenase (G6PD) X-linked deficiency is the most common human enzymopathy. Case Description/Methods: A 73-year-old male presented with loss of appetite, and dark colored urine. On examination, vitals were within normal range. Scleral icterus was present, along with hepatomegaly. Patient was alert and oriented. Patient's lab work was concerning for AST was 3017 unit/L, ALT 2712 Unit/L, BUN 74 mg/dL, Cr 3.6 mg/dL, total bilirubin 72.4 mg/dL, direct bilirubin 41.8 mg/dL, indirect bilirubin 30.6 mg/dL, hemoglobin 12.9 g/dL, white count 17,000 per microliter and platelet count of 173,000 per microliter (mcL). Patient’s hepatitis panel was positive for Hepatitis B Core Antibody Total, Hepatitis B Core Antibody IgM, Hepatitis B Surface Antibody, log 10 HBV IU/mL 2914. Hematological work up was done which was concerning for LDH 4,875, ferritin > 7500, reticulocyte, Peripheral smear did not show schistocytes. Erythrocyte G6PD level was performed which was low Patient was started on hemodialysis due to electrolyte derangement and oliguria. The patient was given intravenous fluids and was started on Entecavir for acute complicated Hepatitis B infection, Renal Biopsy was done which was suggestive of acute tubular injury. Patient liver function, labs as well as renal function continued to improve and no longer required dialysis. Discussion: Hemolytic anemia has been associated with viral hepatitis, but the degree is usually mild to moderate. With cases of severe intravascular hemolysis, a diagnosis in addition to hepatitis should be sought out. Our case is unique since this is the first reported case of severe hemolysis and renal failure precipitated by acute HBV in an undiagnosed G6PD deficient patient and treatment with Entecavir causing marked improvement. With early recognition and establishing diagnosis of complicated hepatitis B leading to severe hemolysis as well as renal failure, prompt treatment with anti-viral as well as supportive treatment for G6PD deficiency can help with early recovery of patients and prevent life threatening organ failure.

Reference Values for Quantitative Testing of G6PD Deficiency in Newborns from the Republic of North Macedonia

Glucose-6-phosphate dehydrogenase is a key regulatory enzyme in the pentose-phosphate cycle that participates in the formation of reduced equivalents to maintain the cellular redox status. The G6PD enzyme activity is crucial in protecting cells from oxidative stress. Deficit of the glucose-6-phosphate dehydrogenase (G6PD) has been recognized as the most common inherited enzymopathy worldwide. In the Republic of North Macedonia (RNM), the deficit of glucose-6-phosphate dehydrogenase has been infrequently investigated. Moreover, no reports exist on quantitative testing of G6PD in newborns from the RNM. SCOPE: The aim of our study was to determine the reference values for the level of G6PD in erythrocytes of newborns from the Republic of North Macedonia. For this purpose, eighty-two healthy newborns were selected and tested for G6PD by the quantitative spectrophotometric method. RESULTS: The mean ± SD of the G6PD quantitative value in the examined group was 229.12 ± 24.2 mU/109Er ranging from a minimum of 191.7 to a maximum of 288, and a median of 228.0 mU/109Er, values that were lower than the preset reference values of the diagnostic test in use. CONCLUSION: We speculated that by establishing a specific reference value (range) for the target population and for the appropriate diagnostic test, we would gain increased sensitivity of the test. This would help optimize detection of G6PD deficient newborns, mild-variant hemizygotes and female heterozygotes for the deficiency.

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.

Sıçan Eritrositlerinde Karbon Tetraklorürün(CCl4) ve Kuersetinin Bazı Metabolik Enzim Aktiviteleri Üzerine İn Vivo Etkisinin İncelenmesi

In the study; the purpose was to investigate the in vivoimpact of carbon tetrachloride (CCl4) and quercetin (Qu) on activities of important metabolic enzymes such as Glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), glutathione reductase (GR) and glutathione S-transferase (GST) in rat erythrocytes. At the experimental stage, rats were divided into 4 groups. 1.Group (Control): Pure olive oil at a dose determined according to their body weight (1mL/kg) was given to the rats in this group, 2.Group (CCl4: 1.0 mL/kg (ip)(1:1), 3.Group (Ku: 25) mg/kg (ip), 4.Group (CCl4(1.0 ml/kg (ip)+ Ku (25 mg/kg (ip) was injected. The study was continued for 3 days.The results revealed that the activities of; G6PD (p˂0.01), 6PGD (p˂0.01), GR(p˂0.001) and GST (p˃0.05) enzyme activities were decreased in the CCl4group compared to the control group. It was determined that enzyme activities were higher in CCl4+Qu applied groups compared to CCl4group.The application of Qu caused an increase in the enzyme activity value. This can be accepted as an indication that the inhibition caused by CCI4has disappeared. Consequently; It is thought that Qu may be effective in preventing oxidative damage due to CCl4administration.

Artemisinin and l-carnitine combination therapy alters the erythrocytes redox status.

Hematopoiesis is a sensitive target of artemisinin (ART) and its derivatives, and hemolysis is one of their commonly reported side effects. l-carnitine (LC), an amino acid derivative involved in lipid metabolism, is beneficial for hematological parameters. Sixty adult laboratory mice were randomly divided into six groups. Group I (control) received saline and corn oil; groups II and III received therapeutic (50 mg/kg) and toxic (250 mg/kg) doses of ART, respectively; groups IV and V received 370 mg/kg LC along with the 50 and 250 mg/kg ART, respectively; and group VI received 370 mg/kg LC. Drugs were administered orally for 7 consecutive days. The erythrocyte glucose 6-phosphate dehydrogenase (G6PD), catalase (CAT), and peroxidase (POX) activity, and the reduced glutathione (GSH) level were assessed by colorimetric methods. ART reduced the G6PD activity both at therapeutic and toxic doses. The therapeutic dose of ART reduced the CAT activity and the GSH level, nonsignificantly. The toxic dose of ART reduced the CAT activity and increased the POX activity. LC reduced the G6PD, CAT, and POX activities and increased GSH level. The therapeutic dose of ART and LC showed synergy in reducing the G6PD activity. LC and ART combination reduced POX activity and increased GSH level without any significant effect on the CAT activity. Inhibition of G6PD may be a potentially new mechanism of ART action. Coadministration of LC with ART or following treatment with ART may have protective effects on erythrocytes.

Stabilization of glucose-6-phosphate dehydrogenase oligomers enhances catalytic activity and stability of clinical variants

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a genetic trait that can cause hemolytic anemia. To date, over 150 nonsynonymous mutations have been identified in G6PD, with pathogenic mutations clustering near the dimer and/or tetramer interface and the allosteric NADP+-binding site. Recently, our lab identified a small molecule that activates G6PD variants by stabilizing the allosteric NADP+ and dimer complex, suggesting therapeutics that target these regions may improve structural defects. Here, we elucidated the connection between allosteric NADP+ binding, oligomerization, and pathogenicity to determine whether oligomer stabilization can be used as a therapeutic strategy for G6PD deficiency (G6PDdef). We first solved the crystal structure for G6PDK403Q, a mutant that mimics the physiological acetylation of wild-type G6PD in erythrocytes and demonstrated that loss of allosteric NADP+ binding induces conformational changes in the dimer. These structural changes prevent tetramerization, are unique to Class I variants (the most severe form of G6PDdef), and cause the deactivation and destabilization of G6PD. We also introduced nonnative cysteines at the oligomer interfaces and found that the tetramer complex is more catalytically active and stable than the dimer. Furthermore, stabilizing the dimer and tetramer improved protein stability in clinical variants, regardless of clinical classification, with tetramerization also improving the activity of G6PDK403Q and Class I variants. These findings were validated using enzyme activity and thermostability assays, analytical size-exclusion chromatography (SEC), and SEC coupled with small-angle X-ray scattering (SEC-SAXS). Taken together, our findings suggest a potential therapeutic strategy for G6PDdef and provide a foundation for future drug discovery efforts.

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.

Assessment of serum aflatoxin B1 levels in neonatal jaundice with glucose-6-phosphate dehydrogenase deficiency: a preliminary study.

Aflatoxin (AF) contamination of food products is still a major health issue globally. Prior studies suggest that exposure to AFs during pregnancy has harmful fetal outcomes. This preliminary study was designed to assess serum AFB1 levels in neonatal jaundice (NNJ) secondary to glucose-6-phosphate dehydrogenase (G6PD) deficiency. Twenty-four full-term neonates with hemolytic jaundice secondary to G6PD deficiency were enrolled in the study. Erythrocyte G6PD status was assessed colorimetrically, and serum aflatoxin B1 (AFB1) concentrations were measured by high-performance liquid chromatography. The results revealed that AFB1 was detected in 58% (14/24) of the studied newborns while detected in 75% (18/24) of their mothers. AFB1 positive cases had a highly significantly lower birthweight and G6PD activity (P=0.001, each). Birthweight (r=-0.574, P=0.032) and G6PD activity (r=-0.585, P=0.028) negatively correlated with serum AFB1 levels while serum alanine aminotransferase activity positively correlated with serum AFB1 levels (r=0.536, P=0.048). Maternal AFB1 exposure is associated with adverse birth outcomes as verified by the low birthweight and the evident decline in the activity of G6PD enzyme with the resultant hemolytic NNJ.

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.

The Synthesis of Thiosemicarbazone-Based Aza-Ylides as Inhibitors of Rat Erythrocyte Glucose 6-Phosphate Dehydrogenase Enzyme

Glucose 6-phosphate dehydrogenase (G6PD) enzyme plays an important role in various biochemical processes such as synthesis of cholesterol, fatty acids, sphingosine, steroid hormones, NADPH, some amino acids and ribose 5-phosphate. In this study, thiosemicarbazone-based aza-ylide (TSCAs) derivatives 3a-3e, which form the main framework of many drugs such as thioacetazone, ambazone, and perchlozone, were synthesized with a green approach and in vitro inhibitor or activator effects on G6PD enzyme activity was investigated. As a result of studies, TSCAs derivatives 3a-3d inhibited the G6PD enzyme activity with IC50 in the range of 40.77 μM to 58.0 μM for G6PD.

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.

The Effect of Mercury Chloride and Boric Acid on Rat Erythrocyte Enzymes

The aim of this study was to investigate the effects of mercury chloride and boric acid on rat (Wistar albino) erythrocyte: glucose 6-phosphate dehydrogenase (G6PD), 6-phosphoglucona-te dehydrogenase (6PGD), thioredoxin reductase (TrxR), glutathione reductase (GR) and glutathione S-transferase (GST) enzymes in vivo, and the rat erythrocyte G6PD enzyme in vitro. In the in vivo study, 24 male rats were divated into three different groups: control (C), mercury chloride (M), and mercury chloride + boric acid (M + BA). At the completion of this study, a significant degree of inhibition for both G6PD and GST enzyme activity was observed in the M groups when compared to the C group (p < 0.05), and no significant effect was observed in the 6PGD enzyme. However, there was significantly increased TrxR and GR enzyme activity of both the M and M + BA groups (p < 0.05). In the in vitro study, the G6PD enzyme from rat erythrocytes was purified with 2',5'-ADP Sepharose-4B affinity chromatography, and the effect of both mercury chloride and boric acid on the enzyme activity was investigated. The results showed that boric acid increased the G6PD enzyme activity while the mercury ions that inhibited the enzyme activity (IC50 values of 346μM and Ki values of 387μM) were noncompetitive.

Evaluation of oxidative stress and antioxidant status, serum trace mineral levels and cholinesterases activity in cattle infected with Anaplasma marginale

This study was undertaken to assess the influence of an Anaplasma marginale infection on oxidative stress and antioxidant status, trace elements and cholinesterase as markers of the inflammatory process and biomarkers of oxidative imbalance. An infected group comprised of 35 crossbred Holstein cattle, about 2–3 years old, naturally infected with Anaplasma marginale, were divided into 4 subgroups according to their parasitemia rates (<1%, 1–10%, 10–20%, >20%) and also 10 healthy cattle as control were selected. Blood samples were taken and hematological parameters, activities of antioxidant enzymes including erythrocyte glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), glucose-6-phosphate dehydrogenase (G6PD), total antioxidant capacity (TAC), median corpuscularfragility (MCF) as well as acetylcholinesterase (AChE), and serum concentrations of antioxidant trace minerals (copper, iron, zinc, manganese, and selenium) and butyrylcholinesterase (BChE) were determined. In addition, as an index of lipid peroxidation, the level of malondialdehyde (MDA) was measured. The results revealed a significant decrease (P < 0.05) in RBC count, packed cell volume (PCV) and Hb concentration as well as the activities of erythrocyte GSH-Px, SOD, CAT, G6PD, TAC, MCF and AChE and serum concentrations of Cu, Zn, Mn, Se and BchE in the infected cattle. In contrast, significantly increased (P < 0.05) levels of MDA and erythrocyte osmotic fragility as well as serum concentration of iron were recorded in the infected animals. The significant decrease in antioxidant enzyme activities and substantial elevated levels of lipid peroxidation and erythrocyte osmotic fragility associated with the notable increase in parasitemia indicate increased exposure of RBCs to oxidative damage. Furthermore, decrease of cholinesterase in infection by A. marginale can and directly or indirectly lead to increase acetylcholine levels potent anti-inflammatory molecules, thereby inhibiting inflammation.

In vitro effects of some antibiotics on glucose-6-phosphate dehydrogenase from rat (Rattus norvegicus) erythrocyte

Glucose-6-phosphate dehydrogenase (G6PD) plays a key function in various biochemical processes as they produce reducing power of the cell. Thus, metabolic reprogramming of nicotinamide adenine dinucleotide homeostasis is reported to be an important step in cancer progression as well as in combinational therapeutic approaches. In this study, the effects of the antibiotics, furosemide, cefazolin, cefuroxime, gentamicin and clindamycin on rat erythrocyte G6PD enzyme was studied in in vitro conditions. The enzyme was purified by 2', 5'-adenosine diphosphate Sepharose 4B affinity chromatography in a single purification step with 1825 fold and 83.7% yield. The specific activity of the enzyme was 29.2 EU/mg proteins. The inhibition studies of these antibiotics were carried out on the enzyme revealing that gentamicin, clindamycin and furosemide inhibited the activity of the G6PD with an IC50 of 1.75, 34.65 and 0.526 mM, respectively with Ki of 0.7, 39.8 and 0.860 mM, respectively. All inhibition types were analyzed by Lineweaver-Burk diagram showing noncompetitive inhibition for furosemide and gentamicin while clindamycin inhibited the activity competitively. On the other hand, cefazolin and cefuroxime increased the activity of the enzyme.

Erythrocyte and spermatozoa glucose-6-phosphate dehydrogenase activity in merino rams: An experimental study

Glucose-6-phosphate dehydrogenase (G6PD) is the first enzyme of the pentose phosphate metabolic pathway that supplies reducing agents by maintaining the level of reduced nicotinamide adenine dinucleotide phosphate. It was aimed to determine the activity of erythrocyte and spermatozoa G6PD in the breeding and non-breeding seasons in Merino rams. And also, to find out the relation of these parameters with sperm quality parameters for better understanding the role of this enzyme in male fertility. 1.5-2 yr-old healthy, 14 Merino rams were involved. Ejaculate samples were collected using an artificial vagina, in October (the breeding season) and April (the non-breeding season). Blood samples were collected prior to sperm collection. Sperm volume (ml), motility (%), mass activity (1-5), concentration (×106), viability (%), abnormal acrosome morphology (%) and abnormal sperm morphology (%) was evaluated. The activities of spermatozoa and erythrocyte G6PD were determined and the relation of sperm parameters with G6PD activity was evaluated. Erythrocyte G6PD activity was higher (p≤0.001), whereas spermatozoa G6PD activity was lower (p≤0.001) in the breeding season (1.928±0.231 U/g hemoglobin, 129.65±28.41 U/g protein, respectively) from that in the non-breeding (0.530±0.066 U/g hemoglobin, 562.36±94.92 U/g protein, respectively). There were also significant differences among sperm quality parameters within the seasons. Positive correlation was determined between spermatozoa G6PD activity (r=0.053, p=0.03 and sperm concentration in the breeding season. Higher spermatozoa G6PD activity in October, where the level of polyunsaturated fatty acids is suggested to be increased, may reflect the increased need of nicotinamide adenine dinucleotide phosphate and thus higher G6PD activity for the oxidative balance.

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).