Role of paraoxonase 1 activity and PON1 gene polymorphisms in sickle cell disease.

Sickle cell disease (SCD) patients often exhibit a dyslipidemic sub-phenotype. Paraoxonase 1 (PON 1) is a serum glycoprotein associated with the high-density lipoproteins cholesterol (HDL-C), and variability in PON1 activity depends on the PON1 genotypes. We investigated the influence of PON1c.192Q > R and PON1c.55L > M polymorphisms on PON1 activity and laboratory parameters and the association between PON1 activity and clinical manifestations in SCD patients. We recruited 350 individuals, including 154 SCD patients and 196 healthy volunteers, which comprised the control group. Laboratory parameters and molecular analyses were investigated from the participants' blood samples. We have found increased PON1 activity in SCD individuals compared to the control group. In addition, carriers of the variant genotype of each polymorphism presented lower PON1 activity. SCD individuals carrying the variant genotype of PON1c.55L > M polymorphism had lower platelet and reticulocyte counts, C-reactive protein, and aspartate aminotransferase levels; in addition to higher creatinine levels. SCD individuals carrying the variant genotype of PON1c.192Q > R polymorphism had lower triglyceride, VLDL-c, and indirect bilirubin levels. Furthermore, we observed an association between PON1 activity history of stroke and splenectomy. The present study confirmed the association between PON1c.192Q > R and PON1c.55L > M polymorphisms and PON1 activity, in addition to demonstrate their effects on markers of dislipidemia, hemolysis and inflammation, in SCD individuals. Moreover, data suggest PON1 activity as a potential biomarker related to stroke and splenectomy.

Leg Ulcers in Sickle Cell Disease: A Multifactorial Analysis Highlights the Hemolytic Profile.

Sickle cell disease (SCD) is characterized by the presence of the variant S hemoglobin (HbS). The homozygous genotype (HbSS) is sickle cell anemia (SCA), while the double heterozygous of HbS and HbC (HbSC) is defined as SC hemoglobinopathy. The pathophysiology is based on chronic hemolysis, inflammation, endothelial dysfunction, and vaso-occlusion, which results in vasculopathy and serious clinical manifestations. Sickle leg ulcers (SLUs) are cutaneous lesions around the malleoli frequent in 20% of Brazilian patients with SCD. SLUs present a variable clinical and laboratory pattern modulated by several characteristics that are not fully understood. Hence, this study aimed to investigate laboratory biomarkers and genetic and clinical parameters associated with the development of SLUs. This descriptive cross-sectional study included 69 SCD patients, 52 without SLU (SLU-) and 17 with active or previous SLU history (SLU+). The results showed a higher incidence of SLU in SCA patients and there was no observed association of α-3.7 Kb thalassemia in SLU occurrence. Alterations in NO metabolism and hemolysis were associated with clinical evolution and severity of SLU, in addition to hemolysis modulating the etiology and recurrence of SLU. Our multifactorial analyses demonstrate and extend the role of hemolysis driving the pathophysiological mechanism of SLU.

A Description of the Hemolytic Component in Sickle Leg Ulcer: The Role of Circulating miR-199a-5p, miR-144, and miR-126.

Sickle leg ulcers (SLU) are malleoli lesions with exuberant hemolytic pathophysiology. The microRNAs are potential genetic biomarkers for several pathologies. Thereby, we aimed to assess the expression of circulating miR-199a-5p, miR-144, and miR-126 in association with hemolytic biomarkers in SLU. This cross-sectional study included 69 patients with sickle cell disease, 52 patients without SLU (SLU-) and 17 patients with active SLU or previous history (SLU+). The results demonstrated elevated expression of circulating miR-199a-5p and miR-144 in SLU+ patients while miR-126 expression was reduced. Circulating miR-199a-5p and miR-144 were associated with hemolytic biomarkers such as LDH, indirect bilirubin, AST, GGT, iron, ferritin, RBC, hemoglobin, and NOm, in addition to association with impaired clinical profile of SLU. Furthermore, in silico analyses indicated interactions of miR-199a-5p with HIF1A, Ets-1, and TGFB2 genes, which are associated with vasculopathy and reduced NO. In contrast, miR-126 was associated with an attenuating clinical profile of SLU, in addition to not characterizing hemolysis. In summary, this study demonstrates, for the first time, that hemolytic mechanism in SLU can be characterized by circulating miR-199a-5p and miR-144. The circulating miR-126 may play a protective role in SLU. Thus, these microRNAs can support to establish prognosis and therapeutic strategy in SLU.

Sickle Cell Anemia: Variants in the CYP2D6, CAT, and SLC14A1 Genes Are Associated With Improved Hydroxyurea Response.

Differences in hydroxyurea response in sickle cell anemia may arise due to a series of factors with genetic factors appearing to be predominant. This study aims to investigate the effects of single nucleotide polymorphisms in genes encoding drug-metabolizing enzymes and solute carriers on hydroxyurea response, in patients with sickle cell anemia. For that purpose, a total number of 90 patients with sickle cell anemia were recruited, 45 were undergoing hydroxyurea treatment, while 45 were not under the treatment. Association analyses were performed between CYP3A4 (rs2740574), CYP2D6 (rs3892097), CAT (rs7943316 and rs1001179), and SLC14A1 (rs2298720) variants and laboratory parameters. According to our findings, patients with hydroxyurea treatment demonstrated higher HbF levels and a significant improvement in hemolytic, hepatic, inflammatory, and lipid parameters in comparison to those without the treatment. We also found significant associations between the CYP2D6 (rs3892097), CAT (rs7943316 and rs1001179), and SLC14A1 (rs2298720) variants and an improvement of the therapeutic effects, specifically the hemolytic, hepatic, inflammatory, lipid, and renal parameters. In conclusion, our results highlight the importance of the investigated variants, and their strong association with hydroxyurea efficacy in patients with sickle cell anemia, which may be considered in the future as genetic markers.

An evaluation of ticagrelor for the treatment of sickle cell anemia.

INTRODUCTION: Ticagrelor is an antiplatelet agent approved for the treatment of patients with an acute coronary syndrome or a history of myocardial infarction. Considering the evidence demonstrating that ticagrelor-mediated inhibition of platelet activation and aggregation have beneficial effects in the treatment of thrombotic conditions, clinical studies have been conducted to evaluate the use of this drug for the treatment of sickle cell disease (SCD), demonstrating satisfactory tolerability and safety. AREAS COVERED: Clinical investigation has characterized the pharmacokinetic and pharmacodynamical profile, as well as the efficacy and safety of ticagrelor to prevent painful vaso-occlusive crisis (painful episodes and acute chest syndrome) in SCD patients. EXPERT OPINION: While phase 1 and 2 clinical trials demonstrated satisfactory tolerability and safety, the conclusion of phase 3 clinical trials is crucial to prove the efficacy of ticagrelor as a therapeutic option for the treatment of SCD. Thus, it is expected that ticagrelor, especially in combination with other drugs, will improve the clinical profile and quality of life of patients with SCD.

Effect of N(Epsilon)-(carboxymethyl)lysine on Laboratory Parameters and Its Association with ß S Haplotype in Children with Sickle Cell Anemia.

The present study aimed to investigate the association of N ε -carboxymethyllysine (CML) with laboratory parameters and ß S haplotypes in pediatric sickle cell anemia (SCA) patients with or without hydroxyurea (HU) therapy. We included 55 children with SCA (SCAtotal), where 27 were on HU treatment (SCA-HU+) and 28 without HU treatment (SCA-HU-). Laboratory characteristics were determined using electronic methods while CML was measured using competitive ELISA. ß S haplotypes were determined by RFLP-PCR. Significant increases in MCV and MCH and significant decreases in leukocytes, eosinophils, basophils, atypical lymphocytes, lymphocytes, and monocytes were found in SCA-HU+ compared to SCA-HU-. SCA-HU+ presented significant reduction in aspartate transaminase and lactate dehydrogenase and increase in creatinine levels compared to SCA-HU-. CML levels were significantly higher in both SCA-HU+ and SCA-HU- compared to the healthy control. In addition, a negative correlation was found between CML and alanine transaminase in SCA-HU+ and SCAtotal (p < 0.01). A significant association was found between CML levels and ß S haplotypes. The results suggest that CML has a role to play in SCA complications, independent of HU therapy.

Hydroxyurea alters hematological, biochemical and inflammatory biomarkers in Brazilian children with SCA: Investigating associations with ßS haplotype and α-thalassemia.

This study investigated the effects of hydroxyurea (HU) on hematological, biochemical and inflammatory parameters in children with sickle cell anemia (SCA) in association with ßS haplotype and α-thalassemia. We included 22 children with SCA who were followed for an average of 14.5 months. Laboratory parameters were assessed by electronic methods, and molecular analysis was investigated by PCR-RFLP and allele-specific PCR. Results showed significant increases in hemoglobin, HbF, hematocrit, MCV, MCH, glucose, HDL-C and albumin levels, as well as significant decreases in MCHC and AST levels, WBC, neutrophils, eosinophils, lymphocytes and reticulocytes, in children during HU therapy. HbF levels were positively correlated with hemoglobin, hematocrit, MCV and total protein, yet negatively correlated with MCHC, RDW, AAT and AST during HU therapy (p<0.05). Children who carried the Central African Republic haplotype, in response to HU therapy, presented significant increases in hemoglobin, hematocrit, triglycerides and uric acid levels, as well as significant decreases in MCHC, AST and direct bilirubin levels, WBC, neutrophils, eosinophils, lymphocytes and reticulocytes. Those with the Benin haplotype presented increases in HbF and albumin levels, and a reduction in platelet counts (p<0.05). Children with α-thalassemia presented decreased ALT during HU use, while those without this deletion presented increases in hemoglobin, hematocrit, MCV, MCH, HDL-C and albumin, as well as decreases in MCHC, neutrophils, lymphocytes, reticulocytes and AST (p<0.05). Hence, regardless of its use in association with ßS haplotypes or α-thalassemia, HU seems to be linked to alterations in hemolytic, inflammatory, hepatic, lipid and glycemic profiles.

Hydroxyurea in the management of sickle cell disease: pharmacogenomics and enzymatic metabolism.

Hydroxyurea (HU) was approved to be used in the treatment of sickle cell disease (SCD) because of its anti-sickling potential. However, there is variability in HU response among SCD patients and this can be due to physiological, socioeconomic, environmental, metabolic and/or genetic factors. The present review focuses on the latter two. Three quantitative trait loci, HBG2, BCL11A and HMIP, have been suggested as important markers for HU response. Other genes (ASS1, KLF10, HAO2, MAP3K5, PDE7B, TOX, NOS1, NOS2A, FLT1, ARG1, ARG2, UGT1A1, OR51B5/6, SIN3A, SALL2, SAR1A, UTB, OCTN1, CYP2C9, AQP9, MPO, CYP2E1, and GSTT1) have also been considered. Studies implicate catalase, urease, horseradish peroxidase and enzymes of CYP450 family in HU metabolism. However, little is known about these enzymes. Therefore, further studies are needed to elucidate the metabolic pathway of HU, which will facilitate pharmacogenomic studies and help in identification of candidate genes for predicting HU response.

Genetic Polymorphisms Associated with Environmental Exposure to Polycyclic Derivatives in African Children.

BACKGROUND: The nonracial leukopenia may be a result of exposure to polycyclic derivatives (benzene-toluene-xylene (BTX)) and may arise from a possible change in the bone marrow microenvironment. The present study sought to evaluate the association of genetic polymorphisms in xenobiotic-metabolizing enzymes with hematological and biochemical profiles. METHODS: We evaluated 89 African descendant children, exposed indirectly to benzene derivatives. Laboratory parameters were investigated by automated methods and genetic polymorphisms by PCR-RFLP and PCR multiplex. RESULTS: Children with leukopenia had significantly decreased white blood cells (WBCs) and platelet counts, which is not consistent with benign leukopenia. In the same group, we have found that carriers of the CYP2E1 variant allele had decreased WBC and lymphocytes. Those with NQO1 variant allele had decreased WBC, neutrophil, eosinophil, monocyte, and lymphocyte counts. Carriers of the MPO variant allele had decreased WBC, neutrophil, eosinophil, basophil, monocyte, lymphocyte, and platelet counts and an elevated free iron level. Children with GSTT and GSTM null exhibited decreased WBC, neutrophil, basophil, and lymphocyte counts. Our multivariate analysis model reveals that females were independently associated with leukopenia. CONCLUSION: Our results suggest that the polymorphisms investigated were associated with hematological changes in the studied population. These alterations could be heightened by exposure to benzene derivatives.

Sickle Cell Anemia Patients in Use of Hydroxyurea: Association between Polymorphisms in Genes Encoding Metabolizing Drug Enzymes and Laboratory Parameters.

This study investigated associations between SNPs in genes encoding metabolizing drug enzymes and laboratory parameters in sickle cell anemia patients under hydroxyurea (SCA-HU+). We evaluated hematologic and biochemical parameters by electronic methods and SNPs by PCR-RFLP and multiplex PCR in 35 SCA-HU+ patients and 67 SCA-HU- patients. The HbS, total cholesterol, lactate dehydrogenase, aspartate aminotransferase, total bilirubin and fractions levels, and leukocyte, eosinophil, monocyte, and erythroblast counts were reduced in SCA-HU+ patients (p < 0.05). Moreover, they presented higher HbF, C-reactive protein, and ferritin levels and elevated MCH and MCV values (p < 0.05). Genotype frequencies of variants GA + AA of MPO -463G>A and c1c2 + c2c2 of CYP2E1 -1293G>C/-1053C>T were higher in SCA-HU+ patients (p < 0.05). Independent associations were found between the variant A allele and lower total cholesterol, between c2 allele and low alpha-1 antitrypsin and between the null GSTT1 variant and high indirect and total bilirubin in SCA-HU+ patients. In SCA-HU- patients, independent associations were found between the variant A allele and high uric acid and between c2 allele and high urea. Our results suggest that SNPs MPO -463G>A, CYP2E1 -1293G>C/-1053C>T, and GSTT1 can be associated with alterations in lipid, inflammatory, renal, hemolytic, and hepatic profiles. However, further studies are needed to elucidate these associations.

Evaluation of Cardiometabolic Parameters among Obese Women Using Oral Contraceptives.

BACKGROUND: Combined oral contraceptive (COC) use has been associated with an unfavorable impact on carbohydrate and lipid metabolism in diverse populations of normal weight and obese women. The present study aimed to evaluate the cardiometabolic and inflammatory profiles of women in northeastern Brazil with respect to COC use and obesity. METHODS: We performed a cross-sectional study to verify cardiovascular parameters, including blood pressure (BP), fasting serum glucose, lipid, and inflammatory profile, in a population of women aged 15-45 years, considering obesity and COC use. Our sample consisted of 591 women, 481 women who were COC users, and 110 age-matched women who were COC non-users, classified as obese and non-obese according to BMI. RESULTS: COC use and obesity were associated with increased systolic (p ≤ 0.001) and diastolic BP (p = 0.001), blood glucose (p ≤ 0.001), total cholesterol (p = 0.008), low-density lipoprotein cholesterol (p ≤ 0.001), very low-density lipoprotein cholesterol (p ≤ 0.001), triglycerides (p ≤ 0.001), ferritin (p = 0.006), C-reactive protein (CRP) (p ≤ 0.001), and nitric oxide metabolites (p ≤ 0.001), as well as decreased high-density lipoprotein cholesterol (HDL-c) (p ≤ 0.001) in comparison to controls. CRP and HDL-c levels in obese COC users were determined to be outside reference range values. The odds of having lower levels of HDL-c and elevated CRP increased among obese COC users. COC use was independently associated with low levels of HDL-c, especially second-generation progestins (p < 0.001; OR = 8.976; 95% CI 2.786-28.914). CONCLUSION: Obesity and COC use were associated with alterations in lipid and inflammatory cardiometabolic parameters, particularly increased CRP levels and decreased HDL-c, which are considered markers of cardiovascular disease (CVD) risk. Given the need to prevent unintended pregnancy among obese women, together with weight loss counseling, it is important to evaluate the most effective and safest contraceptive methods to avoid the potential risk of developing CVD.

Association of classical markers and establishment of the dyslipidemic sub-phenotype of sickle cell anemia.

BACKGROUND: Sickle cell anemia (SCA) patients exhibit sub-phenotypes associated to hemolysis and vaso-occlusion. The disease has a chronic inflammatory nature that has been also associated to alterations in the lipid profile. This study aims to analyze hematological and biochemical parameters to provide knowledge about the SCA sub-phenotypes previously described and suggest a dyslipidemic sub-phenotype. METHODS: A cross-sectional study was conducted from 2013 to 2014, and 99 SCA patients in steady state were enrolled. We assessed correlations and associations with hematological and biochemical data and investigated the co-inheritance of -α3.7Kb-thalassemia (-α3.7Kb-thal). Correlation analyses were performed using Spearman and Pearson coefficient. The median of quantitative variables between two groups was compared using t-test and Mann-Whitney. P-values <0.05 were considered statistically significant. RESULTS: We found significant association of high lactate dehydrogenase levels with decreased red blood cell count and hematocrit as well as high levels of total and indirect bilirubin. SCA patients with low nitric oxide metabolites had high total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol and reduced very low-density cholesterol, triglycerides, direct bilirubin level and reticulocyte counts. In SCA patients with high-density lipoprotein cholesterol greater than 40 mg/dL, we observed increased red blood cell count, hemoglobin, hematocrit, and fetal hemoglobin and decreased nitric oxide metabolites levels. The presence of -α3.7Kb-thal was associated with high red blood cell count and low mean corpuscular volume, mean corpuscular hemoglobin, platelet count and total and indirect bilirubin levels. CONCLUSIONS: Our results provide additional information about the association between biomarkers and co-inheritance of -α3.7Kb-thal in SCA, and suggest the role of dyslipidemia and nitric oxide metabolites in the characterization of this sub-phenotype.

Determinação de HbA1c por CLAE: interferência de variantes de hemoglobinas S e C e alta concentração de HbF / HbA1c determination by HPLC: interference of hemoglobin variants HbS, HbC and HbF high concentration

INTRODUÇÃO: O diabetes mellitus (DM) é considerado um problema importante de saúde pública; possui prevalência elevada e nos últimos anos observa-se aumento progressivo na sua incidência. OBJETIVO: verificar possíveis variações na concentração de hemoglobina (Hb) glicada (HbA1c) na presença de Hbs S e C e avaliar o impacto da redução da HbA1c na avaliação clínica e no monitoramento do paciente diabético. MATERIAL E MÉTODOS: Foram incluídos no estudo, 150 indivíduos diabéticos oriundos da cidade de Salvador, Bahia, de ambos os gêneros, com idade média de 56 anos. Foram determinadas a glicemia de jejum e a HbA1c por metodologia de oxidase-peroxidase e cromatografia líquida de alta eficiência (CLAE), respectivamente. RESULTADOS: Foram observadas variações na concentração da HbA1c em função da presença de variantes de Hb, como 7,85%, AA; 7,30%, AS e 7,15%, AC. DISCUSSÃO E CONCLUSÃO: A metodologia analítica a ser utilizada para determinação de HbA1c deve ser escolhida com base nas características gerais da população atendida e nas comorbidades associadas, pois a presença de Hbs S e C ocasiona reduções significativas de glicação. Essa redução pode levar a interpretações clínicas inadequadas relativas ao controle glicêmico dos pacientes.

INTRODUCTION: Diabetes mellitus (DM) is considered an important public health problem. It is highly prevalent and its incidence has progressively increased in recent years. OBJECTIVE: To verify possible variations of glycated hemoglobin (HbA1c) concentration in the presence of Hb S and Hb C and to evaluate the impact of HbA1c reduction on clinical evaluation and monitoring of diabetic patients. MATERIAL AND METHODS: This study comprised 150 diabetic individuals from Salvador city, Bahia, from both genders and average age of 56 years old. Fast blood glucose and HbA1c were determined by oxidase-peroxidase and high-performance liquid chromatography (HPLC) methods, respectively. RESULTS: There were variations in the concentration of HbA1c in the presence of hemoglobin variants such as AA (7.85%), AS (7.30%), and AC (7.15%). DISCUSSION AND CONCLUSION: The analytical method used to determine HbA1c needs to be chosen according to the general population characteristics and associated comorbidities, since the presence of hemoglobin S and C causes significant reductions in hemoglobin glycation, which may lead to clinical misinterpretation of patients' glycemic control.

Clinical and molecular characteristics of sickle cell anemia in the northeast of Brazil

Beta S-globin gene (âS-globin) haplotypes, markers for severe sickle cell anemia (SCA), and the alpha-thalassemia 2 gene 3.7 kb deletion (-á2(3.7 kb) thal) along with demographic and clinical data were investigated in SCA outpatients (n = 125, 63 female and 62 male) in the Brazilian state of Bahia, which has a high prevalence SCA. PCR-RFLP showed that the Central African Republic/Benin (CAR/BEN, 51.2 percent) haplotype was most frequent, followed by the Benin/Benin (Ben/Ben, 28.8 percent). At least one CAR haplotype was present in every outpatient with a history of cerebrovascular accident. The Cameroon (Cam), Senegal (Sen) and Arab-India haplotypes occurred in small numbers, as did atypical haplotypes. Fetal hemoglobin (HbF, percent) was unevenly distributed. Compared to those > 18 y, those aged < 18 y had had fewer erythrocyte transfusions and high HbF levels (12.3 percent ± 7.01 to 7.9 percent ± 4.36) but a higher frequency of spleen sequestration and pneumonia. Compared with normal á - genes carriers values, the outpatients with -á2(3.7 kb) thal (determined by PCR analysis) had significantly higher mean hemoglobin concentration (Hb) (8.3 ± 1.34 g/dL, p = 0.018) and packed cell volume (PCV = 27.1 percent ± 4.26, p = 0.019) but low mean corpuscular volume (MCV = 86.1 fL = 10-15 L ± 9.56, p = 0.0004) and mean corpuscular hemoglobin (MCH = 26.6 percent ± 4.60, p = 0.039).

Hemoglobinopathies in newborns from Salvador, Bahia, Northeast Brazil.

Hemoglobinopathies are hereditary disorders of the hemoglobin molecule with a high prevalence worldwide. Brazil has a prevalence of 0.1 to 0.3% of newborns with sickle cell anemia and 20.0 to 25.0% of heterozygous alpha2 thalassemia among African Brazilians. In the present study, we investigated the presence of variant hemoglobins and alpha2(3.7 Kb) and alpha2 (4.2 Kb) thalassemia in newborns from Salvador, Bahia, Brazil. Samples of umbilical cord blood from a total of 590 newborns were analyzed, of which 57 (9.8%) were FAS; 36 (6.5%) FAC; one (0.2%) SF; and five (0.9%) FSC. One hundred fourteen (22.2%) newborns had alpha2(3.7 Kb) thalassemia, of whom 101 (19.7%) were heterozygous and 13 (2.5%) homozygous, showing statistical significance for hematological data between newborns with normal alpha genes and alpha2(3.7 Kb) thalassemia carriers. The alpha2(4.2 Kb) thalassemia was not found. Frequencies found in the present study confirm that hemoglobinopathies are a public health problem in Brazil, emphasizing the need for neonatal screening and genetic counseling programs.

Hemoglobinopathies in newborns from Salvador, Bahia, Northeast Brazil

Hemoglobinopatias são alterações hereditárias na molécula de hemoglobina com prevalência mundial elevada. O Brasil apresenta prevalência de 0,1 a 0,3por cento para recém-nascidos com anemia falciforme e freqüência de 20,0 a 25,0 por cento para a ocorrência de heterozigotos da talassemia alfa sobrescrito 2 entre indivíduos afro-descendentes. O presente estudo investigou a presença de hemoglobinas variantes e talassemia alfa 2 subscrito 2 sobrescrito 3.7kb e alfa subscrito 2 sobrescrito 4.2Kb em recém-nascidos de Salvador, Bahia, Brasil. Analisamos o sangue do cordão umbilical de 590 recém-nascidos, sendo 57 (9,8 por cento) com padrão FAS; 36 (6,5 por cento) FAC; um (0,2 por cento) SF e cinco (0,9 por cento) FSC. Cento e catorze (22,2 por cento) apresentaram talassemia alfa 2 subscrito 2 sobrescrito 3.7kb, dos quais 101 (19,7 por cento) foram heterozigotos e 13 (2,5 por cento) homozigotos, mostrando significância estatística para os dados hematológicos entre recém-nascidos com genes a normais e portadores de talassemia alfa 2 subscrito 2 sobrescrito 3.7kb. A talassemia alfa subscrito 2 sobrescrito 4.2Kb não foi encontrada. As freqüências descritas neste trabalho confirmam que as hemoglobinopatias são um problema de Saúde Pública no Brasil, enfatizando a importância dos programas de triagem neonatal e aconselhamento genético.

Anemia falciforme em Salvador - Bahia: caracterização fenotípica, molecular e de sequências gênicas potencialmente importantes na expressão dos genes gama da hemoglobina fetal / Sickle cell anemia in Salvador - Bahia: phenotype and molecular characterization and search of specific gene sequences potentially important to gama gennes expression of the fetal hemoglobin

(...) O estudo investigou as características fenopíticas e os marcadores moleculares presentes em portadores da anemia falciforme de Salvador-BA, identificando seqüências gênicas potencialmente importantes para a expressão dos genes gama. O perfil de hemoglobinas e o nível de HbF foram determinados por cromatografia líquida de alta performance (HPLC). Informações sobre o perfil clínico dos pacientes foram obtidas através da análise de prontuários. A talassemia alfa2 3.7kb foi investigada pela reação em cadeia da polimerase (PCR) e os haplótipos ligados ao grupo de genes da globina betaS foram investigados por PCR e análise de sítios polimórficos utilizando endonucleases de restrição (RFLP) (...) Foram analisados 131 pacientes, dos quais 125 tiveram identificado o genótipo BetaS, tendo sido encontrado 64 (51,2 por cento) CAR/Ben; 36 (28,8 por cento) Ben/Ben; 18 (14,4 por cento) CAR/CAR; dois (1,6 por cento) Ben/Cam; um (0,8 por cento) CAR/Cam; um (0,8 por cento) Car/Arábia-India e um (0,8 por cento) Sen/Aty. A talassemia alfa2 3.7kb foi estudada em 110 pacientes, onde 30 (27,3 por cento) foram heterozigotos e dois (1,8 por cento) homozigotos. O uso de transfusão sanguínea foi maior em pacientes com HbF menor ou igual 10,0 por cento (p=0,009). Pacientes com genótipos alfa diferentes apresentaram diferenças para os valores de Hb (p=0,018); Ht (p=0,019); VCM (p=0,0004) e HCM (p=0,039). Os níveis de HbF foram maiores entre os pacientes Ben/Ben que entre os CAR/CAR (p=0,007) e CAR/Ben (p=0,013). A análise das seqüências do HS2-LCR de dez indivíduos demonstrou a substituição G-A na posição -10.677, presente apenas entre os portadores do haplótipo Ben com nível elevado de HbF, sugerindo uma possível associação entre este polimorfismo, a expressão dos genes y e a síntese da HbF. A análise da região promotora do gene yG demonstrou a substituição T-C na posição -157, que parece ser uma seqüência característica entre os pacientes estudados. Também foi encontrada a deleção de 4 pb na posição -222 a -225 no gene yG e relacionado ao haplótipo Cam. Os dados demonstraram um novo polimorfismo localizado no HS2-LCR e na região promotora do gene yG da globina, justificando a realização de estudos adicionais, associando os níveis de HbF, marcadores biológicos e mecanismos relacionados, visando esclarecer um possível papel no desenvolvimento do fenótipo da doença

The beta-globin gene cluster haplotypes in sickle cell anemia patients from Northeast Brazil: a clinical and molecular view.

The beta(S)-globin haplotypes were studied in 78 sickle cell Brazilian patients from Bahia, Northeast Brazil, that has a large population of African origin. Hemoglobin (Hb) profiles were developed by high-performance liquid chromatography (HPLC), and beta(S)-globin gene haplotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques. We identified 44 (55.0%) patients with the CAR/Ben (Central African Republic/Benin) genotype, 16 (20.0%) Ben/Ben, 13 (16.2%) CAR/CAR and seven (8.8%) with other genotypes. Analyses of the phenotypes showed clinical differences related only to Hb F levels and blood transfusion therapy; the presence of -alpha(-3.7)-thalassemia (thal) demonstrated statistical significance when associated with hematocrit (p=0.044), MCV (p=0.0007), MCH (p=0.012) and spleen sequestration events. The haplotype diversity found in the present study can be justified by information about the origin of the slave traffic period in Bahia during the 19th century. The specific characteristics described among the Bahian sickle cell patients could be confirmed by increasing the number of patients with specific genotypes and further studies of genetic markers.

C677T polymorphism of the MTHFR gene and variant hemoglobins: a study in newborns from Salvador, Bahia, Brazil.

The C677T polymorphism in the methylenetetrahydrofolate reductase gene (MTHFR) is associated with an increase in total homocysteine serum levels (tHcy), described as a risk factor for cardiovascular disease. Eight hundred forty-three neonates from two different maternity hospitals, one public and another private, in Salvador, Bahia, Brazil were screened for this polymorphism by PCR and RFLP. The T-allele frequency in the total sample was 0.23, and the prevalence rates of heterozygous and homozygous carriers were 36.2% and 5.3%, respectively. The T-allele frequency differed and the T/T genotype was more prevalent at the private maternity hospital. The hemoglobin (Hb) profile was investigated by HPLC in 763 newborns. The frequency of variant Hb was higher at the public than at the private maternity hospital. The association of the C677T polymorphism and the Hb profile was investigated in 683 newborns, showing a relatively high frequency of variant Hbs and the T allele. These data could provide an important basis for further studies focusing on potential risks of vaso-occlusive events in these individuals.

C677T polymorphism of the MTHFR gene and variant hemoglobins: a study in newborns from Salvador, Bahia, Brazil

O polimorfismo C677T no gene da MTHFR tem sido associado ao aumento dos níveis séricos de homocisteína.total (tHcy), descrito como fator de risco para o desenvolvimento de doenças cardiovasculares. Oitocentos e quarenta e três recém-nascidos (RNs), de duas maternidades diferentes, uma pública e a outra privada, em Salvador, Bahia, Brasil foram triados para o polimorfismo C677T por PCR e RFLP. A freqüência do alelo T foi de 0,23 e as prevalências dos genótipos C/T e T/T foram de 36,2 por cento e 5,3 por cento, respectivamente. A freqüência do alelo T diferiu e a prevalência do genótipo T/T foi mais elevada entre os RNs da maternidade privada. O perfil de hemoglobinas (Hb) foi determinado por HPLC em 763 RNs. A freqüência de Hbs variantes foi mais elevada entre os RNs da maternidade pública Tsylla Balbino do que na maternidade privada do Hospital Santo Amaro. A associação do polimorfismo C677T e o perfil de Hbs foram estudados em 683 RNs, apresentando freqüência elevada da coexistência do alelo T e Hb variantes. Estes resultados podem ser utilizados como base para estudos futuros sobre riscos potenciais de eventos vaso-oclusivos nestes indivíduos.