Metabolic profiling reveals alterations in the erythrocyte response to fava bean ingestion in G6PD-deficient mice.

BACKGROUND: Favism is an acute hemolytic syndrome caused by fava bean (FB) ingestion. The purpose of this study was to investigate the possible influences of FB on the metabonomic profile of erythrocytes in glucose-6-phosphate dehydrogenase (G6PD)-deficient (G6PDx) and wild-type (WT) mice. RESULTS: Ninety-two metabolites were identified in the comparison of the G6PDx and WT groups. Eighty-seven metabolites were identified in the erythrocytes of WT and G6PDx mice after FB ingestion. Thirty-eight metabolites were identified in the comparison of the FB-treated G6PDx and the FB-treated WT mouse groups. Among them, the number of glycerophospholipids (GPLs) and polyunsaturated fatty acids (PUFAs) changed significantly, which suggests that GPLs and PUFAs may be responsible for FB stress. CONCLUSION: This study demonstrates that G6PD deficiency might affect the metabonomic profile of erythrocytes in response to FB. © 2020 Society of Chemical Industry.

A practical toxicity bioassay for vicine and convicine levels in faba bean (Vicia faba).

BACKGROUND: Faba bean (Vicia faba) vicine and convicine (V-C) aglycones (divicine and isouramil respectively) provoke an acute hemolytic anemia called favism in individuals with a glucose-6-phosphate dehydrogenase (G6PD) enzyme defect in their red blood cells. Geneticists/plant breeders are working with faba bean to decrease V-C levels to improve public acceptance of this high-protein pulse crop. Here, we present a fast and simple ex vivo in vitro bioassay for V-C toxicity testing of faba bean or faba bean food products. RESULTS: We have shown that 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU)-treated (i.e., sensitized) normal red blood cells, like G6PD-defective blood, displayed (i) continuous glutathione (GSH) depletion with no regeneration as incubation time and the dose of aglycones increased, (ii) progressive accumulation of denatured hemoglobin products into high molecular weight (HMW) proteins with increased aglycone dose, (iii) both band 3 membrane proteins and hemichromes, in HMW protein aggregates. We have also demonstrated that sensitized red blood cells can effectively differentiate various levels of toxicity among faba bean varieties through the two hemolysis biomarkers: GSH depletion and HMW clumping. CONCLUSION: BCNU-sensitized red blood cells provide an ideal model for favism blood, to assess and compare the toxicity of faba bean varieties and their food products. © 2018 Society of Chemical Industry.

Association between ACP(1) genetic polymorphism and favism.

An association between favism (a hemolytic reaction to consumption of fava beans), glucose-6-phosphate dehydrogenase deficiency (G6PD(-)) and acid phosphatase locus 1 (ACP(1)) phenotypes has been reported; the frequency of carriers of the p(a) and p(c) ACP(1) alleles was found to be significantly higher in G6PD(-) individuals showing favism than in the general population. Here, we investigated the hypothesis that favism is caused by toxic Vicia faba substances, which in some ACP(1) phenotypes cause increased phosphorylation and consequently increased glycolysis, with strong reduction in reduced glutathione production, resulting in hemolysis. It has been demonstrated that ACP(1) f isoforms have physiological functions different from those of s isoforms and are responsible for most of the phosphatase activity, in addition to being less stable in the presence of oxidizing molecules. Thus, the C, CA and A phenotypes, characterized by lower concentrations of f isoforms, could be more susceptible to damage by oxidative events compared to the other phenotypes. To test this hypothesis, the (f+s) enzymatic activity of different ACP(1) phenotypes with and without added V. faba extract was analyzed. Enzymatic activities of ACP(1) A, -CA, -C groups (low activity) and -B, -BA, -CB groups (high activity) were significantly different after addition of V. faba extract. Phenotypes A, CA and C had extremely low enzymatic activity levels, which would lead to low levels of reduced glutathione and bring about erythrocyte lysis.

Favism: association with erythrocyte acid phosphatase phenotype.

The frequency of carriers of the P(a)and P(c) alleles of the gene for acid phosphatase in the erythrocyte is significantly higher in male subjects deficient in glucose-6-phosphate dehydrogenase and having hemolytic clinical favism than it is in the general population. This observation seems to indicate that alleles (P(a) and P(c)) of a gene polymorphic in all human populations affect the fitness of the involved phenotypes in special genotypic and nongenotypic conditions.

Severe hemolysis and methemoglobinemia following fava beans ingestion in glucose-6-phosphatase dehydrogenase deficiency: case report and literature review.

INTRODUCTION: Reduced concentrations of glucose-6-phospate dehydrogenase (G6PD) render erythrocytes susceptible to hemolysis under conditions of oxidative stress. In favism, the ingestion of fava beans induces an oxidative stress to erythrocytes, leading to acute hemolysis. DISCUSSION: The simultaneous occurrence of methemoglobinemia has been reported only scarcely, despite the fact that both phenomena are the consequence of a common pathophysiologic mechanism. The presence of methemoglobinemia has important diagnostic and therapeutic consequences. We report a previously healthy boy who presented with combined severe hemolytic anemia and cyanosis due to methemoglobinemia, following the ingestion of fava beans. His condition was complicated by the development of transient acute renal failure. A G6PD-deficiency was diagnosed. We review the literature on the combination of acute hemolysis and methemoglobinemia in favism. Pathophysiologic, diagnostic, and therapeutic aspects of this disorder are discussed.

Inactivation of red cell glutathione peroxidase by divicine and its relation to the hemolysis of favism.

A significant inactivation of red blood cell glutathione peroxidase (25% less than the physiological value) was observed after exposure of intact erythrocytes to 2 mM divicine (an autoxidizable aminophenol from Vicia faba seeds) and 2 mM ascorbate for 3 h at 37 degrees C. Addition of catalase and conversion of Hb to the carbomonoxy derivative resulted in protection against enzyme inactivation. Oxidation of Hb was a concurrent phenomenon, and augmented the inactivating effect. In hemolysates, much stronger effects were observed at shorter times (2 h); divicine was effective also without ascorbate, and the presence of reductants (ascorbate or glutathione or NADPH) enhanced its inactivating power. Of the other antioxidant enzymes, superoxide dismutase was unaffected under the same experimental conditions. Catalase was found to be much less sensitive to the inactivation; it was almost unaffected in experiments with intact erythrocytes and specifically protected by NADPH in experiments with hemolysates. This specific damage of glutathione peroxidase, apparently involving interaction of H2O2 and HbO2, may be related to the pathogenesis of hemolysis in favism.

An Ashkenazi Jewish woman presenting with favism.

The case of a 44 year old Ashkenazi Jewish woman of Russian origin who presented with a typical clinical and haematological picture of favism is reported. There was initial difficulty in confirming glucose-6-phosphate dehydrogenase (G6PD) deficiency because the enzyme concentrations were normal at presentation, but later fell to a concentration compatible with heterozygosity for the Mediterranean type of G6PD deficiency. The diagnosis was also later confirmed by gene analysis. The reasons for the difficulties in the initial confirmation of the diagnosis and the normal G6PD enzyme activity at presentation are discussed.

Favism: divicine hemotoxicity in the rat.

Favism is an acute hemolytic anemia known to occur in susceptible individuals who ingest fava beans. Susceptibility to favism is conferred by a genetic deficiency in erythrocytic glucose-6-phosphate dehydrogenase (G6PD) activity. Although the fava bean pyrimidine aglycones, divicine and isouramil, have been implicated in the onset of favism in humans, the lack of a well-defined experimental animal model for favism has hampered progress in elucidating the mechanism underlying hemotoxicity. We have examined whether a favic-like response could be provoked in G6PD-normal rats treated with synthetic divicine. Intraperitoneal administration of divicine to rats preloaded with 51Cr-tagged erythrocytes resulted in a severe, dose-dependent decrease in blood radioactivity (TD50 approximately 0.5 mmol/kg) within 24 h. The increased rate of removal of blood radioactivity was accompanied by a rapid decline in reduced glutathione levels in the blood, decreased hematocrits, marked hemoglobinuria, splenic enlargement, and reticulocytosis. In vitro exposure of 51Cr-tagged red cells to divicine before their re-administration to isologous rats also resulted in a sharp, concentration-dependent decrease in erythrocyte survival in vivo (TC50 approximately 1.5 mM), and these divicine-damaged red cells were removed from the circulation by the spleen. These data demonstrate that a favic response can be induced in G6PD-normal rats treated with divicine, and that hemolytic activity can be reproduced in isolated red cells under conditions that will allow a direct examination of the mechanism underlying this hemotoxicity.

Low-molecular-weight protein tyrosine phosphatase and human disease: in search of biochemical mechanisms.

A major challenge in the post-genomic era is to identify the physiological functions of genes and elucidate the molecular basis for human disease. Genetic polymorphisms offer a convenient avenue for these efforts by providing evidence for the involvement of a given gene in human pathophysiology. Here we review the current evidence linking the low-molecular-weight protein tyrosine phosphatase (LMPTP) to several common diseases, including allergy, asthma, obesity, myocardial hypertrophy, and Alzheimer's disease. Based on the known effects of the genetic polymorphisms on the alternative mRNA splicing and enzyme levels of LMPTP, we discuss the possible molecular mechanisms of LMPTP involvement in these diseases.

Glucose-6-phosphate dehydrogenase revisited.

Hemolytic diseases associated with drugs have been recognized since antiquity. Many of these anemias have been associated with oxidizing agents and deficiencies in the intraerythrocytic enzyme glucose-6-phosphate dehydrogenase. This paper outlines the discovery, prevalence, and variants of this enzyme. Methods of diagnosis of associated anemias are offered.

[The glucose-6-phosphate dehydrogenase/6-phosphogluconate dehydrogenase ratio in the identification of glucose-6-phosphate dehydrogenase heterozygosity]. / Il rapporto G-6PD/6-PGD nella identificazione dell' eterozigosi per la G-6PD.

Deficiency in human G-6PD is a widespread X-linked disorder, which is mainly characterized by susceptibility to hemolytic anaemia after the ingestion of certain drugs or toxic substances (e.g. pyrimidine derivates contained in fava beans). G-6PD deficiency in hemizygous males in easily detectable since enzymatic activity is almost absent. In heterozygous subjects the determination of enzymatic activity on red cell lysate cannot detect a partial G-6PD deficiency. Cytochemical methods as methemoglobin reduction test or tetrazolium reduction test are more sensitive than spectrophotometric quantitative test, but are not suitable for screening purposes. We measured both G-6PD activity and 6-PGD activity in G-6PD heterozygous females and we evaluated the G-6PD/6PGD ratio. We tested this ratio also in thalassemic traits and in G-6PD heterozygotes with thalassemic trait in order to detect the interference of thalassemic pathology with the phenotypic expression of the gene for G-6PD. We found that the mean G-6PD values were statistically reduced in G-6PD heterozygous females; on the contrary the measurement of true G-6PD activity alone is not a good tool for discriminating heterozygous subjects with and without thalassemic trait. Actually 100% and 79% of values observed were in the normal range +/- 2 DS respectively. The mean G-6PD/6-PGD ratio in heterozygotes for G-6PD deficiency with and without thalassemic trait was lower than normal and the individual values of G-6PD/6-PGD ratio were in the normal range +/- 2 DS only in a few subjects (8.3% and 10.7% respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of Mediterranean mutation in Egyptian favism patients.

OBJECTIVES: Identify and screen the G6PD Mediterranean mutation in favism patients by applying a Amplification Refractory Mutation System Polymerase Chain Reaction (ARMS-PCR). PATIENTS AND METHODS: A total of 114 unrelated Egyptians patients were included in the present study; their ages ranged between (2-9) years with male to female ratio 4.5:1. G6PD activity was determined qualitatively from red cell hemolysate during attack. The G6PD Mediterranean mutation in patients has been identified by ARMS-PCR. RESULTS: G6PD deficiency was detected in 87.7%, (n=100). The frequency of G6PD Mediterranean mutation was (94.7%), (n=108). The association between G6PD deficiency and Mediterranean mutation was a highly significant. CONCLUSIONS: Glucose-6-phosphate dehydrogenase Mediterranean mutation is one of the most common mutations causing G6PD deficiency among Egyptian children with favism.

[A boy with jaundice]. / Een jongetje met icterus.

A 1-year-old Moroccan boy was referred because of jaundice. A peripheral blood smear showed 'blister cells'. This finding is characteristic for haemolysis caused by glucose-6-phosphate dehydrogenase deficiency. It appeared hemolysis occurred because the boy ate fava beans.