The clinical impact of MTHFR polymorphism on the vascular complications of sickle cell disease

Sickle cell disease (SCD) is one of the most common inherited diseases in the world and the patients present notorious clinical heterogeneity. It is known that patients with SCD present activation of the blood coagulation and fibrinolytic systems, especially during vaso-occlusive crises, but also during the steady state of the disease. We determined if the presence of the factor V gene G1691A mutation (factor V Leiden), the prothrombin gene G20210A variant, and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism may be risk factors for vascular complications in individuals with SCD. We studied 53 patients with SCD (60% being women), 29 with SS (sickle cell anemia; 28 years, range: 13-52 years) and 24 with SC (sickle-hemoglobin C disease; 38.5 years, range: 17-72 years) hemoglobinopathy. Factor V Leiden, MTHFR C677T polymorphism, and prothrombin G20210A variant were identified by PCR followed by further digestion of the PCR product with specific endonucleases. The following vascular complications were recorded: stroke, retinopathy, acute thoracic syndrome, and X-ray-documented avascular necrosis. Only one patient was heterozygous for factor V Leiden (1.8%) and there was no prothrombin G20210A variant. MTHFR 677TT polymorphism was detected in 1 patient (1.8%) and the heterozygous form 677TC was observed in 18 patients (34%, 9 with SS and 9 with SC disease), a prevalence similar to that reported by others. No association was detected between the presence of the MTHFR 677T allele and other genetic modulation factors, such as alpha-thalassemia, ß-globin gene haplotype and fetal hemoglobin. The presence of the MTHFR 677T allele was associated with the occurrence of vascular complications in SCD, although this association was not significant when each complication was considered separately. In conclusion, MTHFR C677T polymorphism might be a risk factor for vascular complications in SCD.Universidade Federal de São Paulo (UNIFESP) Paulista de Medicina Disciplina de Hematologia e HemoterapiaUNIFESP, Paulista de Medicina Disciplina de Hematologia e HemoterapiaSciEL

Functional phage display of leech-derived tryptase inhibitor (LDTI): construction of a library and selection of thrombin inhibitors

The recombinant phage antibody system pCANTAB 5E has been used to display functionally active leech-derived tryptase inhibitor (LDTI) on the tip of the filamentous M13 phage, A limited combinatorial library of 5.2 x 10(4) mutants was created with a synthetic LDTI gene, using a degenerated oligonucleotide and the pCANTAB 5E phagemid. the mutations were restricted to the P1-P4' positions of the reactive site. Fusion phages and appropriate host strains containing the phagemids were selected after binding to thrombin and DNA sequencing. the variants LDTI-2T (K8R, I9V, S10, K11W, P12A), LDTI-5T (K8R, I9V, S10, K11S, P12L) and LDTI-10T (K8R, I9L, S10, K11D, P12I) were produced with a Saccharomyces cerevisiae expression system. the new inhibitors, LDTI-2T and -5T, prolong the blood clotting time, inhibit thrombin (Ki 302 nM and 28 nM) and trypsin (K-i 6.4 nM and 2.1 nM) but not factor Xa, plasma kallikrein or neutrophil elastase, the variant LDTI-10T binds to thrombin but does not inhibit it, the relevant reactive site sequences of the thrombin inhibiting variants showed a strong preference for arginine in position P1 (K8R) and for valine in P1' (I9V), the data indicate further that LDTI-5T might be a model candidate for generation of active-site directed thrombin inhibitors and that LDTI in general may be useful to generate specific inhibitors suitable for a better understanding of enzyme-inhibitor interactions. (C) 1999 Federation of European Biochemical Societies.UNIFESP, Dept Bioquim, EPM, BR-04044020 São Paulo, BrazilUniv Munich, Klinikum Innenstadt, Chirurg Klin & Poliklin, Klin Chem & Klin Biochem Abt, D-8000 Munich, GermanyUNIFESP, Dept Med, Disciplina Hematol, EPM, BR-04044020 São Paulo, BrazilUNIFESP, Dept Bioquim, EPM, BR-04044020 São Paulo, BrazilUNIFESP, Dept Med, Disciplina Hematol, EPM, BR-04044020 São Paulo, BrazilWeb of Scienc

Prothrombin G20210A gene mutation, factor V Leiden and anticardiolipin antibodies do not influence renal graft survival after transplantation

INTRODUCTION: Thromboembolic complications are important risk factors for graft failure and worse renal transplantation outcome. Patients with thrombophilic disorders have a higher risk of thromboembolic complications. The prevalence of thrombophilic disorders and the associated risk for graft failure and for intravascular thrombosis were analyzed in renal transplant recipients. METHODS: This is a cohort study of 388 adult recipients investigated regarding the presence of thrombophilia, through the search for anticardiolipin antibodies (aCL) via ELISA and FV G1691A and PT G20210A gene mutations by multiplex PCR. RESULTS: Thrombophilic disorders were identified in 25.8% of the patients. The 2-year graft survival was similar among patients with and without thrombophilic disorder (94% versus 94%, p = 0.53), and so was the survival free of intravascular thrombosis (97% versus 97%, p = 0.83). The prevalence of intravascular thrombosis was similar in both groups (3% versus 3.5%, p = 0.82). Patients with previous kidney transplantation had a higher risk of graft failure (OR 20.8, p < 0.001) and of intravascular thrombosis (OR 6.8, p = 0.008). CONCLUSIONS: The prevalences of FV G1691A and PT G20210A gene mutations in this cohort of patients were similar to those of the general non-transplanted population. The prevalence of aCL antibodies was higher in this cohort than that observed in healthy individuals. The thrombophilic markers studied did not predict the medium-term survival of renal transplant.INTRODUÇÃO: Complicações tromboembólicas são importantes fatores de risco para perda do enxerto e pior evolução após o transplante renal. Pacientes com defeito trombofílico apresentam maior risco de complicações tromboembólicas. Foram analisados, entre receptores de transplante renal, a prevalência de defeito trombofílico e o risco atribuído a esta condição para a perda do enxerto e para o desenvolvimento de tromboses intravasculares. MÉTODOS: Estudo do tipo coorte incluindo 388 receptores adultos analisados quanto à presença de trombofilia de acordo com a pesquisa de anticorpos anticardiolipina (aCL) por ELISA e das mutações G1691A no gene do fator V (FV) e G20210A no gene da protrombina (PT) por PCR multiplex. RESULTADOS: Defeito trombofílico foi identificado em 25,8% dos pacientes. As taxas de sobrevida de 2 anos do enxerto foram semelhantes entre os pacientes com e sem defeito trombofílico (94% versus 94%, p = 0,53), bem como a sobrevida dos enxertos livres de tromboses intravasculares (97% versus 97%, p = 0,83). Pacientes com defeito trombofílico apresentaram prevalência de tromboses intravasculares semelhante à do grupo-controle (3% versus 3,5%, p = 0,82). O transplante renal anterior foi associado a maior risco de perda de enxerto (OR 20,8, p < 0,001) e de ocorrência de tromboses intravasculares (OR 6,8, p = 0,008). CONCLUSÕES: As prevalências das mutações FV G1691A e PT G20210A na população estudada foram semelhantes às da população geral não transplantada, e a prevalência de anticorpos aCL superou a observada entre os indivíduos sadios. Não houve associação entre os marcadores de trombofilia estudados e a sobrevida em médio prazo do transplante renal.UNIFESP Departamento de Medicina, Disciplina de HematologiaUNIFESP Departamento de Medicina, Disciplina de NefrologiaUNIFESP Departameto de Medicina, Disciplina de ReumatologiaUNIFESP Departamento de Medicina Preventiva, Disciplina de BioestatísticaUniversidad de Antofagasta Departamento de Tecnologia MedicaUNIFESP, Depto. de Medicina, Disciplina de HematologiaUNIFESP, Depto. de Medicina, Disciplina de NefrologiaUNIFESP, Departameto de Medicina, Disciplina de ReumatologiaUNIFESP, Depto. de Medicina Preventiva, Disciplina de BioestatísticaSciEL

Hemorrhagic and thrombotic complications in patients with myeloproliferative diseases

OBJECTIVE: To correlate the incidence of hemorrhage and thrombosis to bleeding time (BT) and platelet aggregation in 27 consecutive patients with myeloproliferative diseases (MPD). DESIGN: Retrospective study. SETTING: Public tertiary referral center. PATIENTS: Eighteen patients with chronic myelogenous leukemia (CML), 5 with polycytemia vera (PV), 2 with essential thrombocytemia (ET) and 2 with idiopathic myelofibrosis (MF). Duke's BT and epinephrine-induced platelet aggregation were performed on the patients and on 10 healthy individuals. RESULTS: Eleven patients presented symptoms (41 %): 9 with hemorrhage (33%) and 5 with thrombosis (19%).There were less symptomatic patients in the CML group (28%) than in the other MPD (67%), without statistical significance (Fisher, p=0.06). Duke's BT was longer in symptomatic patients (Mann-Whitney, p<0.05). Platelet aggregation was abnormal in 7 patients (26%) and 71% of them were symptomatic (Fisher, p = 0.07). CONCLUSIONS: The high incidence of bleeding and thrombosis in patients with MPD was related to prolonged BT, but not to platelet aggregation abnormalities

Interleukin-1 beta and interleukin-6 gene polymorphisms are associated with manifestations of sickle cell anemia (vol 54, pg 244, 2014)

Universidade Federal de São Paulo, Escola Paulista Med, Disciplina Hematol & Hemoterapia, BR-04037002 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Dept Psicobiol, São Paulo, BrazilFac Ciencias Med Santa Casa São Paulo, Disciplina Hematol & Oncol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Disciplina Hematol & Hemoterapia, BR-04037002 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Dept Psicobiol, São Paulo, BrazilWeb of Scienc

Hemorrhagic and thrombotic complications in patients with myeloproliferative diseases

OBJECTIVE: To correlate the incidence of hemorrhage and thrombosis to bleeding time (BT) and platelet aggregation in 27 consecutive patients with myeloproliferative diseases (MPD). DESIGN: Retrospective study. SETTING: Public tertiary referral center. PATIENTS: Eighteen patients with chronic myelogenous leukemia (CML), 5 with polycytemia vera (PV), 2 with essential thrombocytemia (ET) and 2 with idiopathic myelofibrosis (MF). Duke's BT and epinephrine-induced platelet aggregation were performed on the patients and on 10 healthy individuals. RESULTS: Eleven patients presented symptoms (41 %): 9 with hemorrhage (33%) and 5 with thrombosis (19%).There were less symptomatic patients in the CML group (28%) than in the other MPD (67%), without statistical significance (Fisher, p=0.06). Duke's BT was longer in symptomatic patients (Mann-Whitney, p<0.05). Platelet aggregation was abnormal in 7 patients (26%) and 71% of them were symptomatic (Fisher, p = 0.07). CONCLUSIONS: The high incidence of bleeding and thrombosis in patients with MPD was related to prolonged BT, but not to platelet aggregation abnormalities.OBJETIVOS: Relacionar a incidência de sintomas trombo-hemorrágicos com tempo de sangramento (TS) e agregação plaquetária em pacientes com doenças mieloproliferativas crônicas (DMP). DESENHO: Estudo retrospectivo. LOCAL: Hospital público terciário - UNIFESP-EPM. Participantes: Vinte e sete pacientes ambulatoriais, consecutivos, com DMP. Estudado TS de Duke e agregação plaquetária induzida pela adrenalina, comparando a 10 indivíduos saudáveis. MENSURAÇÃO: Análise estatística, com nível de significância menor ou igual a 5% (p<= 0.05). RESULTADOS: Onze pacientes sintomáticos (41 %) : 9 com hemorragia (33%) e 5 com trombose (19%). Os pacientes com leucemia mielóide crônica apresentaram menos sintomas (28%) que os portadores de outras DMP (67%), sem significância estatística (Fisher, p=0,06). 0 TS de Duke foi maior em pacientes sintomáticos (Mann-Whitney, p<0,05). Agregação plaquetária anormal em 7 pacientes (26%), sendo 71% sintomáticos (Fisher, p=0.07). CONCLUSÕES: A incidência de hemorragia ou trombose nos pacientes com DMP foi relacionada com TS prolongado mas não com alterações na agregação plaquetária