Status of oxidant, antioxidantand serum enzymes in thalassaemic children receiving multiple blood transfusions.

OBJECTIVE: To determine the levels of oxidant, antioxidant and serum enzymes in thalassaemic children receiving multiple blood transfusions. METHODS: The case-control study was done from February to August 2012, and comprised thalassaemic children receiving multiple blood transfusions at Allied Hospital, Ali Zeb Foundation, and the Thalassaemia Centre in Hilal-e-Ahmar Hospital, Faisalabad, Pakistan. Healthy subjects were also screened for any related disease condition that could prejudice the results. Blood samples were analysed for the values of total oxidant status, total antioxidant capacity, serum malondialdehyde, catalase, paraoxonase, arylesterase, glutathione peroxidase and ceruloplasmin. RESULTS: There were 180 children in the study; 90(50%) cases and 90(50%) controls. Of the cases, 48(53.3%) were under-weight while the weight of 42(46.7%) was in the normal range. The values of total oxidant status and total antioxidant capacity were significantly (p<0.01) higher in thalassaemic children compared to normal values. Serum malondialdehyde and catalase levels were also considerably elevated (p<0.05), suggesting the increased activity of these enzymes. However, the concentrations of serum paraoxonase, arylesterase, glutathione peroxidase were significantly (p<0.01) lower in cases than the controls, displaying diminished activities during multiple blood transfusions in these patients. CONCLUSIONS: Multiple blood transfusions disconcert the levels of oxidants, antioxidants and serum enzymes of thalassaemic children. Oxidative damage is seen because of the increased iron overload in these patients. Hence, regular evaluation of oxidant and antioxidant status should be monitored in thalassaemic patients during initial few years of life.

Cholelithiasis in thalassemia major.

OBJECTIVES: Aim of this study was to evaluate prevalence and characteristics of cholelithiasis in a large population of patients with thalassemia major (TM). METHODS: Data from 858 consecutive patients with transfusion-dependent thalassemia at five major Italian centers were analyzed. In these centers, a complete abdomen ultrasonography is performed yearly after the beginning of the transfusion regimen. The role of co-inheriting Gilbert's syndrome genotype was investigated studying the promoter region of the UGT1-A1 gene by automated sequencing. RESULTS: Thirty percent of TM patients had gallstones. The Gilbert's genotype [homozygosity for (TA)(7) motif at UGT1A promoter gene], influenced both the prevalence of cholelithiasis and the age at which it developed. CONCLUSIONS: Cholelithiasis has a remarkable frequency and precocity in patients with TM and especially in those with (TA)(7)/(TA)(7) UGT1-A1 genotype. An early biliary ultrasonography is recommended from childhood and a closer follow-up in patients with thalassemia and associated Gilbert's syndrome may be indicated.

No detected hepatitis B virus-DNA in thalassemic patients infected by hepatitis C virus in Kerman province of Iran.

This research was aimed to investigate the prevalence and clinical impact of occult HBV infection in thalassemic patients with chronic HCV infection. In this cross-sectional study we have totally examined 60 patients suffering HBV and HCV infections by PCR and RT-PCR methods, respectively, in Kerman province of Iran. ELISA technique (RADIM, Italy) was used to detect anti-HBc, anti-HBs and HBsAg. The serum level of liver enzymes (SGOT, SGPT, DB, TB and ALK) were analyzed in the HCV infected patients (MAN, IRAN). Statistical analyses performed using t-test and Chi-square. We found that 27 cases (out of 60) were infected by HCV but HBV-DNA was not seen in HCV infected patients. Present findings also showed that none of samples were HBsAg positive but 9 (33%) (out of 27) HCV-RNA positive patients were anti-HBc positive and 11 (40.7%) were positive for anti-HBs. We found that SGOT, SGPT, DB, TB and ALK are above normal in 27 (100%), 19(70.3%), 12(44.5%), 15 (55.5%) and 15 (55.5%) RNA-HCV positive patients, respectively. The prevalence of hepatitis C infection is very high in thalassemic patients and based on other studies our results showed that the prevalence of HCV infection in Kerman is more than other provinces of Iran. In contrast with other studies HBV-DNA in these patients could not be detected, hence, it seems that occult HBV infection isn't frequent in Iranian thalassemic patients who suffering from chronic HCV infection.

Chitotriosidase: the yin and yang.

The enzyme chitotriosidase (ChT), the human analogue of chitinases from non-vertebrate species, is one of the most abundant and indicative proteins secreted by activated macrophages. Its enzymatic activity is elevated in serum of patients suffering from Gaucher's disease type 1 and in some other inherited lysosomal storage disorders, as well as in diseases in which macrophages are activated. The last decade has witnessed the appearance of a substantial number of studies attempting to unravel its cellular functions, which have yet not been fully defined. A great deal of progress has been made in the study of the physiological roles of ChT. This review is looks at the key areas of investigations addressed to further illuminate whether ChT activation might have different functional meanings in various diseases.

Intravenous zoledronic acid treatment in thalassemia-induced osteoporosis: results of a phase II clinical trial.

Osteoporosis is an important cause of morbidity in beta-thalassemia patients. Bisphosphonates have been recently used for the treatment of osteoporosis in beta-thalassemia. This study is a prospective quasi-experimental study to assess the efficacy and safety of zoledronic acid in thalassemics with osteoporosis. Eighteen thalassemia patients with osteoporosis were given zoledronic acid 4 mg intravenously every 3 months over a period of 12 months. The efficacy of treatment was assessed by measuring (BMD) at the lumbar spine, femoral neck, and hip at baseline, 6, and 12 months. Z-score was used to measure the BMD. Other medical assessments included markers of bone formation and resorption (bone alkaline phosphatase (BAP), osteocalcin (OC), and urinary deoxypyridinoline), and the assessment of pain score, analgesic score, and performance score. Ten thalassemic osteoporotic patients were followed up only with serial BMDs as controls. Both groups had no significant difference with respect to age, gender, and baseline BMD. Patients taking zoledronic acid had a significant increase in their lumbar spine, femoral neck, trochanter, and total hip BMD measurements over the 12-month period. Patients in the control group did not have any significant change in BMD measurements. There was a significant change in the levels of OC and BAP over the 12-month follow-up period. There was also a significant decrease in the number of painful sites experienced by the patients. Treatment of thalassemic osteoporotic patients with zoledronic acid is very effective in increasing BMD at the lumbar spine and hip and in reducing pain; it is also well-tolerated.

Preliminary study of the effect of vitamin E supplementation on the antioxidant status of hemoglobin-E carriers.

The antioxidant status of hemoglobin-E carriers was studied pre- and post-treatment with vitamin E for 3 months. Fourteen hemoglobin-E carriers (age = 21.36 +/- 1.08 years, BMI = 18.32 +/- 1.22 kg/m2) were treated with vitamin E 200 I.U. daily for 3 months. Fasting blood samples were collected and analyzed for erythrocyte superoxide dismutase activity, total antioxidant activity, hemoglobin concentration, hematocrit, MCV, Heinz body formation and osmotic fragility test. The blood parameters before and after vitamin E treatment were compared. The results showed that superoxide dismutase activity in the erythrocytes was significantly decreased, while total antioxidant activity in plasma, and the osmotic fragility of the erythrocytes, was significantly increased after vitamin E supplementation. However, hematocrit, MCV, and Heinz body formation did not change significantly. This demonstrated that vitamin E 200 IU could be used as a lipophilic antioxidant in red blood cells and could help increase the level of antioxidant in hemoglobin-E carriers.

G6PD/PK ratio: a reliable parameter to identify glucose-6-phosphate dehydrogenase deficiency associated with microcytic anemia in heterozygous subjects.

OBJECTIVES: To determine if measuring the ratio of glucose-6-phosphate dehydrogenase (G6PD) to pyruvate kinase (PK) is more reliable than only measuring G6PD activity to identify heterozygous G6PD- individuals with associated microcytic anemia in the Calabrian population, which shows high frequencies of both the thalassaemia (thal) trait and G6PD deficiency. DESIGN AND METHODS: Measurement of G6PD and PK activities was carried out on 205 samples of whole blood from Calabrian subjects of both sexes (age range 10-50 years) using a double starter differential pH-metry technique. RESULTS: The G6PD/PK ratio is able to differentiate G6PD- heterozygous individuals from the normal population. G6PD/PK values also allowed us to easily identify the G6PD- heterozygous subjects with microcytic anaemia. Student's t test shows that G6PD/PK ratio is more reliable in both sample groups, relative to G6PD activity in normal subjects. CONCLUSIONS: G6PD/PK ratio is a reliable diagnostic parameter for mass screening for G6PD deficiency.

A new glucose 6 phosphate dehydrogenase variant G6PD Sinnai (34 G-->T). Mutations in brief no. 156. Online.

In this paper we report a male infant heterozygous for thalassemia with a mild glucose 6 phosphate dehydrogenase deficiency. The molecular basis of this new Class III G6PD variant is a G-->T mutation at nucleotide 34 in the exon 2, which predicts a Val-->Leu aminoacid substitution at codon 12. We designated this variant as G6PD Sinnai from the place of birth of the propositus.

Radicais livres em eritrócitos falcêmicos e talassêmicos / Free radicals in erythrocytes in sickle cell anemia and thalassemia

Radicais livres derivados de espécies ativadas de oxigênio estao associados a lesoes citológicas, que diminuem a sobrevida dos eritrócitos, especialmente quando contêm defeitos congênitos, como sao os casos da anemia falciforme e da talassemia maior. As atividades antioxidantes dos eritrócitos dependem de três tipos de enzimas: superóxido dismutase, catalase e glutatiao peroxidase. Entretanto, as atividades antioxidantes podem ser ineficazes em situaçoes em que ocorrem o comprometimento dos hidroxiperóxidos da membrana eritrocitária, devido às células falciformes irreversíveis e à ligaçao de hemicromos à membrana dos eritrócitos talassêmicos.

Prevalences of thalassemia/hemoglobinopathies and G-6-PD deficiency in malaria patients.

It seems that thalassemia and/or hemoglobinopathies and glucose-6-phosphate dehydrogenase deficiency (G-6-PD) have some protective effects against malaria infection. To verify this, hemoglobin typing and methehoglobin reduction test were performed on 115 malaria patients and compared with controls. It was found that the number of thalassemia/hemoglobinopathies in the malaria group and in the control group were not significantly different and also occurrence of G-6-PD deficiency in the malaria group was not different from that of the controls. Clinical manifestations of malaria in any group are quite similar. It is concluded that there is no protective effect against malaria in thalassemia/hemoglobinopathies or G-6-PD deficiency.

A modified screening procedure to detect pyruvate kinase deficiency.

Beutler's screening procedure was used to detect pyruvate kinase deficiency in the local population. In this test, hemolysate and the reagent mixture are incubated and then placed at a spot on filter paper to be examined for fluorescence. Complete nonfluorescence marks the reaction endpoint, and fluorescence beyond 30 minutes indicates pyruvate kinase deficiency. It was difficult to determine this endpoint due to uneven sedimentation of unhemolyzed red cells on the spot. In this modified technique, the leukocyte-depleted red cell suspension was frozen and thawed for complete red cell lysis before being used for the test. Using both techniques, 493 health individuals and 126 anemic patients were screened for pyruvate kinase deficiency. By the conventional technique, 3.7% remained fluorescent after 30 minutes, whereas by the modified technique, none were fluorescent after 30 minutes. Quantitative assay indicated that all samples had pyruvate kinase activity levels greater than the lower limit of the reference range. We also demonstrated that blood samples from individuals with thalassemia trait were primarily responsible for the aberrant results from the conventional screening procedure.

Decreased pyrimidine nucleoside monophosphate kinase activity in sickle erythrocytes.

We have previously shown that physiologic concentrations of hemin cause marked inhibition of several red blood cell (RBC) enzymes. Because endogenous heme content is elevated in sickle RBCs, we have examined the activity of hemin-sensitive enzymes in these RBCs. One of the hemin-sensitive enzymes, pyrimidine nucleoside monophosphate kinase (PNMK), was shown to have decreased activity in sickle RBCs relative to RBCs of equivalent cell age. The other hemin-sensitive enzymes, including adenylate kinase (AK), pyrimidine 5'-nucleotidase (P5N), 6-phosphogluconate dehydrogenase (6PGD), and aldolase, had activities that were appropriate for cell age. We have also examined the affinity of the hemin-sensitive enzymes to hemin. Using two different methods, PNMK was shown to have the highest binding affinity to hemin. The exquisite sensitivity of PNMK to inhibition by hemin, coupled with the enzyme's high affinity to hemin, may account for the decrease in PNMK activity and the lack of significant decrease in the other hemin-sensitive enzymes in sickle RBCs. These results suggest that the increased endogenous heme content in sickle RBCs may be responsible for the decrease in PNMK activity. Whether the increased endogenous heme content of sickle RBCs can cause hemolysis indirectly by inhibiting RBC enzymes remains to be determined.

Utilization of red-cell FAD by methaemoglobin reductases at the expense of glutathione reductase in heterozygous beta-thalassaemia.

FAD-dependent methaemoglobin reductases (MHR) were studied in red cells in heterozygous beta-thalassaemia to investigate how they related to low FAD-dependent glutathione reductase (GR). In contrast to GR, MHR activities were usually normal or increased. In particular, whether expressed in relation to haemoglobin or number of red cells, NADPH-MHR activity was markedly increased in most subjects, probably being a response to increased oxidative stress. Oral riboflavin had no effect on MHR activities, indicating saturation with FAD even though GR was deficient. A strong correlation between percent stimulation of GR by FAD and NADPH-MHR activity indicates that FAD is utilized by MHR at the expense of GR. This could be an important influence on GR in heterozygous beta-thalassaemia. Thus, the low activity resulting from an inherited deficiency of FAD is decreased further.

Genetic heterogeneity at the glucose-6-phosphate dehydrogenase locus in southern Italy: a study on a population from the Matera district.

Glucose-6-phosphate dehydrogenase (G6PD) has been analyzed by gel electrophoresis and by quantitative assay in an unselected sample of 1524 schoolboys from the province of Matera (Lucania) in southern Italy. We have identified 43 subjects with a G6PD variant. Of these, 31 had severe G6PD deficiency, nine had mild to moderate deficiency, and three had a non-deficient electrophoretic variant. The overall rate of G6PD deficiency was 2.6%. The frequency of G6PD deficiency, ranging from 7.2% on the Ionian Coast to zero on the eastern side of the Lucanian Apennines, appears to be inversely related to the distance of each town examined from the Ionian Coast, suggesting that this geographic distribution may reflect, at least in part, gene flow from Greek settlers. Biochemical characterization has shown that most of the G6PD deficiency in this population is accounted for by G6PD Mediterranean. In addition, we have found several examples of two other known polymorphic variants (G6PD Cagliari and G6PD A-); three new polymorphic variants, G6PD Metaponto (class III), G6PD Montalbano (class III), and G6PD Pisticci (class IV); and two sporadic variants, G6PD Tursi (class III) and G6PD Ferrandina (class II). These data provide further evidence for the marked genetic heterogeneity of G6PD deficiency within a relatively narrow geographic area and they prove the presence in the Italian peninsula of a gene (GdA-) regarded as characteristically African.

Impaired erythrocyte methemoglobin reduction in sickle cell disease: dependence of methemoglobin reduction on reduced nicotinamide adenine dinucleotide content.

We have examined aspects of methemoglobin (metHb) reduction in sickle and in thalassemic red blood cells (RBCs). NADH metHb reductase activity in sickle and thalassemic RBCs was significantly increased compared with normal RBCs. Because in vitro enzyme activity does not necessarily represent in vivo activity, we measured the rate of metHb reduction in intact RBCs. Intact thalassemic RBCs demonstrated a significantly increased rate of metHb reduction compared with normal RBCs. In contrast, intact sickle RBCs had a rate of metHb reduction that was similar to normal RBCs and significantly decreased relative to high reticulocyte RBCs of equivalent cell age. To determine the mechanism for the relative impairment of metHb reduction in sickle RBCs, we measured intraerythrocytic NADH, a cofactor in the metHb reduction reaction. Thalassemic RBCs had a significantly increased NADH content relative to normal RBCs. In contrast, sickle RBCs did not have an increase in NADH content. Furthermore, incubating normal RBCs under conditions that increase the NADH content resulted in an increased rate of metHb reduction. In contrast, conditions that decrease the NADH content in normal RBC resulted in a decreased rate of metHb reduction. These data and other results suggest that metHb reduction in intact RBCs is dependent on NADH content, and that the impaired metHb reduction rate in sickle RBCs may be a result of a lack of increase in NADH content. The dependence of metHb reduction on RBC NADH content and the ability to manipulate NADH content in vitro suggest a new strategy for decreasing oxidant damage to sickle RBCs in vivo.

Preliminary experience with the differential pH technique for glucose-6-phosphate dehydrogenase (G6PD) measurement in whole blood: application to an area with high prevalence of thalassaemia and G6PD deficiency.

A new differential pH technique for glucose-6-phosphate dehydrogenase quantitative determination in whole blood has been evaluated. It is a rapid (90 s/analysis), reproducible (C.V. within-run 3.7%; between-run: 2.8%) and accurate method (in comparison with WHO method: r = 0.970). Reference intervals in non-deficient males were evaluated in 167 non-thalassaemics and in 60 beta-thal heterozygotes. The G6PD activity in beta-thalassaemia carriers is higher than in normals; this is particularly true if the activity is expressed in terms of U/g Hb. The phenotypic distribution measured in females is in agreement with that calculated by the Hardy-Weinberg law based on the incidence of the Gd(-) gene in males.

Impaired erythrocyte NAD synthesis: a metabolic abnormality in thalassemia.

We have recently demonstrated that phosphoribosylpyrophosphate (PRPP) synthetase activity is decreased in RBC from individuals with thalassemia minor. Because NAD biosynthesis requires PRPP, the product of the PRPP synthetase reaction, we have investigated NAD synthesis in thalassemic RBC. NAD synthesis was measured in intact RBC both by following the accumulation of unlabeled NAD and by following the incorporation of 14C-nicotinic acid into NAD. Using both assay systems, we demonstrate that NAD synthesis is decreased significantly in thalassemic RBC compared to either normal or high reticulocyte red cells. Although this suggested that NAD content should be decreased in thalassemic RBC, no significant difference in NAD content was found among thalassemic, normal, or high reticulocyte red cells. Mechanisms for the lack of a significant decrease in NAD content in thalassemic RBC are discussed. These results indicate that NAD synthesis is impaired in thalassemic RBC possibly as a result of their decrease in PRPP synthetase activity. Our data provide evidence that thalassemic RBC have secondary metabolic abnormalities in addition to their primary defect in hemoglobin synthesis.

Decreased erythrocyte phosphoribosylpyrophosphate synthetase activity and impaired formation in thalassemia minor: a mechanism for decreased adenine nucleotide content.

Adenosine triphosphate (ATP) and adenosine diphosphate levels are decreased in erythrocytes from individuals with beta-thalassemia minor. Because 5-phosphoribosyl-1-pyrophosphate (PRPP) is an essential precurosr of adenine nucleotides, we tested the hypothesis that impaired PRPP synthesis is a mechanism for the decreased adenine nucleotide content. Erythrocyte PRPP synthetase activity was significantly decreased, and the Michaelis-Menten constant (Km) for ribose-5-phosphate (R5P) was significantly increased in individuals with alpha-thalassemia minor and those with beta-thalassemia minor. Intact erythrocytes from individuals with alpha-thalassemia and those with beta-thalassemia minor also had an impaired rate of PRPP formation. Both the decrease in PRPP synthetase activity and the impaired PRPP formation were also found in erythrocytes with microcytosis resulting from iron deficiency, indicating that these phenomena may not be specific to thalassemia minor. In all individuals examined, the rate of PRPP formation correlated with ATP content, suggesting that either (1) PRPP synthetase activity is a determinant of ATP content or (2) ATP content is a determinant of PRPP synthetase activity. The depletion of ATP from normal erythrocytes did not affect PRPP synthetase activity, suggesting that ATP content is not a determinant of PRPP synthetase activity. However, a decrease in PRPP synthetase activity did cause an impairment in the rate of adenine nucleotide synthesis, suggesting that PRPP synthetase activity is a determinant of ATP content. Taken together, our results suggest that the decrease in PRPP synthetase activity and the resulting impairment in the rate of PRPP formation are mechanisms for the decreased adenine nucleotide content in thalassemic erythrocytes.

Occurrence of the erythroid cell specific arachidonate 15-lipoxygenase in human reticulocytes.

Human reticulocytes obtained from patients suffering from various haemolytic disorders convert exogenous [1-14C]-arachidonic acid to 15-hydroxy-5,8,11,13(Z,Z,Z,E)-eicosatetraenoic acid (15-HETE). Immunological studies (dot blot, Western blot) indicated that human reticulocytes contain a lipoxygenase which cross-reacts with a polyclonal antiserum against the rabbit reticulocyte lipoxygenase. Northern blotting with a cloned lipoxygenase cDNA probe shows that the specific mRNA is also present. Reaction of the lipoxygenase with submitochondrial particles caused inactivation of respiratory enzymes. The occurrence of an erythroid cell specific lipoxygenase of similar type in reticulocytes of various mammals and man suggests the general role of this enzyme in the maturational degradation of mitochondria.