Effect of single nucleotide polymorphisms on expression of the gene encoding thrombin-activatable fibrinolysis inhibitor: a functional analysis.

Thrombin-activable fibrinolysis inhibitor (TAFI) is a plasma zymogen that acts as a molecular link between coagulation and fibrinolysis. Numerous single nucleotide polymorphisms (SNPs) have been identified in CPB2, the gene encoding TAFI, and are located in the 5'-flanking region, in the coding sequences, and in the 3'-untranslated region (UTR) of the CPB2 mRNA transcript. Associations between CPB2 SNPs and variation in plasma TAFI antigen concentrations have been described, but the identity of SNPs that are causally linked to this variation is not known. In the current study, we investigated the effect of the SNPs in the 5'-flanking region on CPB2 promoter activity and SNPs in the 3'-UTR on CPB2 mRNA stability. Whereas the 5'-flanking region SNPs (with 2 exceptions) did not have a significant effect on promoter activity, either alone or in haplotypic combinations seen in the human population, all of the 3'-UTR SNPs substantially affected mRNA stability. We speculate that these SNPs, in part, contribute to variation in plasma TAFI concentrations via modulation of CPB2 gene expression through an effect on mRNA stability.

Effect of the G-308A polymorphism of the tumor necrosis factor alpha gene on the risk of ischemic heart disease and ischemic stroke: a meta-analysis.

BACKGROUND: Under the hypothesis that the G-308A polymorphism in the promoter region of the tumor necrosis factor alpha gene might increase tumor necrosis factor alpha expression, several investigations have been performed to examine the influence of the -308A allele on the risk of cardiovascular events. The results of these studies, however, have been conflicting. To provide a more robust estimate of the putative effect of the G-308A polymorphism on the risk of cerebrocardiovascular events, we did 2 meta-analyses that examined the role of the -308A variant in both ischemic heart disease (IHD) and ischemic stroke. METHODS: We applied both fixed- and random-effects models to combine odds ratios (OR) and 95% CIs, and publication bias and heterogeneity were explored. RESULTS: Data of 17,030 subjects from 23 studies were used. Overall, in populations predominantly of European ancestry, no association between the G-308A polymorphism and IHD under a dominant model (AA + GA vs GG) was observed: OR, 1.07; 95% CI, 0.94-1.21; P = .32. Similarly, the -308A allele was not associated with ischemic stroke considering all studies: OR, 0.99; 95% CI, 0.70-1.41, P = .96. However, analysis by ancestry revealed that Asian subjects harboring the -308A variant were approximately 40% less likely to have stroke compared to the GG genotype: OR, 0.62; 95% CI, 0.44-0.86; P = .004. CONCLUSIONS: These results suggest that the G-308A polymorphism is unlikely to be associated with the development of IHD, whereas it might be a protective factor for ischemic stroke in Asians only.

Cytokine gene variants and venous thrombotic risk in the BRATROS (BRAZILIAN THROMBOSIS STUDY).

INTRODUCTION: Venous thrombosis (VT) and inflammation are two closely related entities. In the present investigation we assessed whether there is a relation between genetic modifiers of the inflammatory response and the risk of VT. MATERIALS AND METHODS: 420 consecutive and unrelated patients with an objective diagnosis of deep VT and 420 matched controls were investigated. The frequencies of the following gene polymorphisms were determined in all subjects: TNF-alpha-308 G/A, LT-alpha+252 A/G, IL-6-174 G/C, IL1-ra 86 bp VNTR, IL-10-1082 A/G and CD-31 125 C/G. RESULTS: Overall odds ratio (OR) for VT related to TNF-alpha-308 G/A, LT-alpha+252 A/G, IL-6-174 G/C, A1 allele (4 bp repeat) of the IL1-ra 86 bp VNTR, IL-10-1082 A/G and CD-31 125 C/G were respectively: 1.0 (CI95: 0.8-1.5), 1.3 (CI95: 1.0-1.7), 1.1 (CI95: 0.9-1.5), 1.6 (CI95: 1-2.5), 1.2 (CI95: 0.8-1.7) and 0.8 (CI95: 0.6-1.1). A possible interaction between polymorphisms was observed only for the co-inheritance of the mutant alleles of the LT-alpha+252 A/G and IL-10-1082 G/A polymorphisms (OR=2; CI95: 1.1-3.8). The risk of VT conferred by factor V Leiden and FII G20210A was not substantially altered by co-inheritance with any of the cytokine gene polymorphisms. CONCLUSIONS: Cytokine gene polymorphisms here investigated did not significantly influence venous thrombotic risk.

Liver iron deposits in hepatitis B patients: association with severity of liver disease but not with hemochromatosis gene mutations.

BACKGROUND AND AIMS: Iron deposits in the liver and abnormalities in serum iron biochemistry are frequently observed in patients with chronic liver diseases, but data for patients with hepatitis B virus (HBV) infection are scarce. Moreover, the role of HFE mutations in iron deposits in this condition remains unknown. The aim of the present study was to determine the prevalence of serum iron biochemical abnormalities and iron deposits in the liver of chronic HBV patients, and to evaluate the consequences for the activity and severity of liver disease. Additionally, we studied the role of HFE gene mutations in iron deposits. METHODS: Eighty-one male non-cirrhotic HBV patients were studied. Serum iron biochemistry, liver enzymes and C282Y/H63D mutations were investigated. Liver biopsies were scored for necroinflammatory activity (histological activity index [HAI]), fibrosis and iron deposits. RESULTS: Elevated transferrin saturation (TS) was found in 27.1% of patients and liver iron deposits in 48.7%; these deposits were mild in 68.4% and moderate in 31.6%. Patients with liver iron deposits exhibited significantly higher scores for HAI and fibrosis than those without iron deposits. HFE mutations were identified in 23.4% of patients (14 H63D heterozygotes, four H63D homozygotes, one compound mutation). No difference in the prevalence of C282Y and H63D mutations was observed between HBV patients (1.2% and 23.4%, respectively) and the general population (4.1% and 27.8%, respectively). No association was detected between HFE mutations and elevated TS or liver iron deposits. CONCLUSIONS: Elevated TS and liver iron deposits were frequent in non-cirrhotic HBV patients. Iron deposits were mainly mild and associated with higher activity and severity of liver disease, but not with HFE mutations.

Functional thrombomodulin deficiency causes enhanced thrombus growth in a murine model of carotid artery thrombosis.

Thrombomodulin (TM) bound thrombin initiates the protein C anticoagulant pathway and defects in TM result in enhanced coagulation. Recent studies suggest a role for TM in arterial vascular disease. In order to corroborate this association we studied arterial thrombus formation in mice with a functional TM defect. We used mice homozygous for a (404)Glu-to-Pro mutation in the TM gene (TM(pro/pro)) and compared these with wildtype littermates in a model of FeCl(3) induced carotid artery thrombosis. Time-to-occlusion (TTO) was assessed by arterial blood flow measurement, using a Doppler flow probe. Complete occlusion occurred in 8/10 (80%) TM(pro/pro) mice and in 3/11 (27%) littermate controls. Mean time to occlusion (TTO) [+/- SE] was 767 +/- 196 s in the F2-TM(pro/pro) mice, versus 1507 +/- 159 s in controls (p = 0.007, Mann Whitney U test). Histology and immunostaining for tissue factor did not reveal any differences in thrombus morphology or thrombogenicity between the two groups. These data confirm and extend the finding that a functional deficiency in TM results in enhanced thrombus formation in a murine model of carotid artery thrombosis and support a role for TM defects in arterial thrombotic disease.

Prevalence of factor V Leiden, FII G20210A, FXIII Val34Leu and MTHFR C677T polymorphisms in cancer patients with and without venous thrombosis.

Venous thromboembolism (VTE) is a common complication in patients with malignant disease. In addition to well-established acquired risk factors for VTE, several genetic risk factors, mainly related to the haemostatic system, are known to influence thrombotic risk. However, the contribution of gene abnormalities to thrombotic tendency in cancer patients remains poorly explored. We performed a prospective study to evaluate the prevalence and clinical significance of four gene variations (factor V Leiden [FVL], factor II G20210A, factor XIII Val34Leu and MTHFR C677T) in cancer patients, with and without VTE. Enrolled were 211 unrelated and unselected patients (M/F ratio 0.5, mean age 57 years, range 12-91 years) with a diagnosis of cancer, admitted to two University Oncology Clinics in the city of São Paulo, Southeastern Brazil. After admission, all patients were evaluated for the presence of symptoms and signs of VTE. Sixty-four patients (30.3%) had an episode of deep venous thrombosis (DVT) or pulmonary embolism (PE), which has been objectively verified; 147 patients (69.7%) had no evidence of VTE. FVL was found with a frequency of 1.5% and 2.7% in the VTE and non-VTE group, respectively (odds ratio [OR] for VTE 0.6, 95% CI: 0.06-5.3). FII G20210A was found in 1.5% and 1.3% of thrombotic and nonthrombotic patients, respectively, yielding an OR of 1.2 (95% CI: 0.1-13.1). FXIII Val34Leu was detected in 29.6% of the thrombotic patients and in 28.5% of the non-thrombotic patients (OR 1.1, 95% CI: 0.5-2). MTHFR 677T was present in 53.1% and 60.5% of patients with and without thrombosis, respectively (OR 0.8, 95% CI: 0.4-1.4). The present data do not point to an association between the four polymorphisms here investigated and the risk of VTE in cancer patients.

Host defense and inflammatory gene polymorphisms are associated with outcomes after HLA-identical sibling bone marrow transplantation.

We made the hypothesis that donor and recipient gene polymorphisms that drive the host response to microorganisms could be associated with infections after bone marrow transplantation (BMT). HLA-identical BMT was performed for patients with acute (n = 39) or chronic leukemia (n = 68). Genotyping was performed in 107 D/R DNA pairs for gene polymorphisms of cytokines (tumor necrosis factor-alpha [TNF-alpha] and TNF-beta, interleukin-1 receptor antagonist [IL-1Ra], IL-6, and IL-10), adhesion molecules (CD31 and CD54), Fcgammareceptors (FcgammaRIIa, IIIa, IIIb), mannose-binding lectin (MBL), and myeloperoxidase (MPO). First infection (overall) and first episodes of bacterial, viral, or invasive fungal infection were studied retrospectively for 180 days after BMT. Univariate and multivariate analyses, using death as a competing event, were performed to study risk factors. In multivariate analysis, first overall infections were increased in patients with the FcgammaRIIa R-131 genotype (hazard ratio [HR] = 1.92; P =.04), and severe bacterial infections were increased when the MPO donor genotype was AG or AA (HR = 2.16; P =.03). Viral and invasive fungal infections were not influenced by any genetic factor studied. Interestingly, we also found that (1) time to neutrophil recovery was shorter when donors were FcgammaRIIIb HNA-1a/HNA-1b (HR = 1.77; P =.002); (2) donor IL-1Ra (absence of IL-1RN*2) increased the risk for acute graft-versus-host disease (GVHD) (II-IV) (HR = 2.17; P =.017); and (3) recipient IL-10 (GG) and IL-1Ra genotypes increased the risk for chronic GVHD (P =.03 and P =.03, respectively). Finally, 180-day transplantation-related mortality rates were increased when donors were FcgammaRIIIb HNA-1a/HNA-1a or HNA-1b/HNA-1b (HR = 2.57; P =.05) and donor MPO genotype was AA (HR = 5.14; P =.004). In conclusion, donor and recipient gene polymorphisms are informative genetic risk factors for selecting donor/recipient pairs and could help in the understanding of mechanisms involved in host defenses of BM transplant recipients.

Influence of functional MDR1 gene polymorphisms on P-glycoprotein activity in CD34+ hematopoietic stem cells.

BACKGROUND AND OBJECTIVES: Expression of the multidrug resistance P-glycoprotein, a transmembrane drug transporter, is influenced by recently described polymorphisms of the human MDR1 gene. Hematopoietic cells, such as lymphocytes, and hematopoietic stem cells, express P-glycoprotein, but the effect of MDR1 gene polymorphisms on P-glycoprotein activity in stem cells is unknown. We investigated whether T-129C, G26677T and C3435T polymorphisms influence P-glycoprotein function in stem cells. DESIGN AND METHODS: P-glycoprotein function was evaluated in immunomagnetically purified bone marrow CD34+ cells from 33 healthy bone marrow donors by the flow cytometric rhodamine 123-efflux assay. For T-129C and C3435T, bone marrow donors were genotyped by polymerase chain reaction amplification followed by MspA1I and DpnII digestion analyses, respectively. For the analysis of C2677T, exon 21 was sequenced. RESULTS: P-glycoprotein function was not different among the C3435T genotypes (CC, 38.2 +/- 3.5%; n=17; CT, 42.2 +/- 3.3%; n=11; and TT, 45.0 +/- 5.3%; n=5) nor was it among the C2677T genotypes (CC, 39.4 +/- 2.4%; n=27; CT, 43.7 +/- 6.4%; n=5; and TT, 54.3%; n=1). Among the 33 subjects, three were heterozygotes for the 129C allele (CT) and no mutant homozygote was identified. P-glycoprotein was similar in heterozygotes (TC, 50.6 +/- 2.9%) and wild-type subjects (TT, 39.5 +/- 2.4%). INTERPRETATION AND CONCLUSIONS: These findings suggest that the known functional MDR1 gene polymorphisms are not major determinants of P-glycoprotein function in hematopoietic stem cells. Other genetic variants might influence P-glycoprotein activity in this cell type.

Hemiretinal vein occlusion associated with membranous glomerulonephritis.

PURPOSE: To report a patient in whom the finding of hemiretinal vein occlusion led to the diagnosis of membranous glomerulonephritis. DESIGN: Interventional case report. METHODS: A 44-year-old tennis instructor presented with a 1-week history of blurred vision in the left eye. Examination of the left eye demonstrated a best-corrected visual acuity of 20/40 and an inferior hemiretinal vein occlusion. RESULTS: Blood pressure was normal, and the patient was referred for a medical examination, which revealed membranous glomerulonephritis. The patient was treated with oral prednisone and cyclosporine. Four months after presentation, the left eye demonstrated resolution of the vascular abnormalities and had a best-corrected visual acuity of 20/20. CONCLUSION: Retinal vein occlusion may be associated with membranous glomerulonephritis. Treatment of the systemic disease may be associated with regression of the retinal vascular abnormalities.

Fisiologia da coagulaçäo, anticoagulaçäo e fibrinólise / Overview of coagulation, anticoagulation and fibrinolysis

O presente artigo revisa aspectos de fisiologia dos sistemas de coagulaçäo, anticoagulaçäo e fibrinólise, que säo relevantes para a compreensäo de mecanismos etiopatogênicos operantes em doenças hemorrágicas e trombóticas

Investigaçäo diagnóstica dos distúrbios hemorrágicos / Diagnostic investigation of bleeding disorders

Na presente revisäo, discutimos as ferramentas clínicas e laboratoriais, utilizadas na investigaçäo de distúrbios hemorrágicos

Trombofilias hereditárias / Inherited thrombophilias

Na presente revisäo, discutimos a contribuiçäo de fatores genéticos para a ocorrência de tromboembolismo venoso

Trombofilias adquiridas / Acquired thrombophilias

Na presente revisäo, discutimos a contribuiçäo de fatores de risco adquiridos para a ocorrência de tromboembolismo venoso

Tratamento do tromboembolismo venoso / Treatment of venous thromboembolism

A trombose venosa profunda (TVP) é definida como um episódio de trombose, envolvendo as veias profundas dos membros inferiores. A TVP é freqüentemente acompanhada por embolia pulmonar (EP). Tromboembolismo venoso (TEV) é o termo empregado para designar ambas as eventualidades indistintamente. No presente artigo, oferecemos uma breve revisäo dos conceitos atualmente preconizados para o tratamento do TEV. Säo abordados aspectos relativos à utilizaçäo da heparina näo fracionada, aos novos esquemas terapêuticos com as heparinas de baixo peso molecular e à transiçäo para o tratamento clássico com anticoagulantes orais a longo prazo. Adicionalmente, säo discutidas condutas em situações clínicas especiais, além de medidas terapêuticas que se mostraram eficazes no tratamento de pacientes com TEV

Novas drogas anticoagulantes / Novel anticoagulant drugs

A presente revisäo discute as características e o uso clínico potencial de novos agentes anticoagulantes, com ênfase para os inibidores dos fatores da coagulaçäo IIa (trombina), IXa, Xa e FVIIa/fator tecidual, e para agentes que potencializam os mecanismos anticoagulantes e fibrinolíticos

Coagulaçäo intravascular disseminada / Disseminated intravascular coagulation

Na presente revisäo, revisamos diversos aspectos da etiologia, fisiopatologia, diagnóstico e tratamento da coagulaçäo intravascular disseminada (CIVD)

Molecular diseases: The role of genetic factors in venous thrombosis

As doenças multigênicas são aquelas em que o fenótipo clínico é resultante da interação de diferentes mutações em diversos genes. Embora o risco da ocorrência da doença determinado por cada defeito genético isoladamente possa ser baixo, a presença simultânea de várias mutações aumenta o risco da sua ocorrência. As doenças mutigênicas podem também ser vistas como consequentes à interação de uma coleção heterogênia de fatores genéticos e ambientais. O conceito de doença multigênica aplica-se a numerosas condições clínicas como o cancer, hipertensão, diabetes, dislepidemia, obesidade, suscebilidade a infecções, doenças auto-imunes, osteoporose, aterosclerose e tromboembolismo venoso. Como uma grande proporção dos pacientes com trombose venosa ou embolia pulmonar tem uma tendência hereditária a hipercoagulabilidade, o termo "trombofilia" foi introduzido para descrever a predisposição genética aumentada à trombose venosa. Numerosos fatores genéticos que têm uma relação bem estabelecida ou suspeita com trombofilia foram ou estão sendo identificados: Mutações dos genes de antitrombina, de proteína C, proteína S, fatores genéticos em casos individuais permite compreender a tendência hereditária ao tromboembolismo sob uma base mais objetiva e quantificável