Polimorfismo genético do fibrinogênio na doença arterial periférica / Genetic polymorphisms of fibrinogen in peripheral artery disease

O objetivo do presente estudo foi analisar freqüências alélicas e genotípicas para o gene codificador da cadeia beta do fibrinogênio em pacientes com doença arterial periférica (DAP). Foram estudados 44 pacientes caucasóides do sexo masculino com sintomas clínicos e comprovação angiográfica de DAP, com idade entre 38 e 79 anos (62±8,6 anos). Entre eles, 22 apresentaram obstrução aterosclerótica nas artérias ilíacas, femorais e/ou carótidas e 22 tinham aneurisma de aorta torácica, abdominal ou tóraco-abdominal. O grupo controle foi constituído por 56 indivíduos, sem história clínica de DAP ou alterações ao exame clínico, com idades variando de 43 a 80 anos (59±9,2 anos). Foram excluídos os indivíduos com doença renal, doença hepática ou diabetes mellitus. A análise do polimorfismo genético da cadeia do fibrinogênio foi realizada por PCR (polimerase chain reaction) e RFLP (restriction fragment lenght polimorphism) com a endonuclease Bcl I, identificando-se três genótipos: B1/B1, B1/B2 e B2/B2. A análise estatística incluiu teste exato de Fisher, calculo do odds ratio, teste de Kruskal Wallis e análise de variância (ANOVA). Admitiu-se erro a igual a 5 por cento, com nível de significância para P<0,05. O alelo B1 foi o mais prevalente em pacientes e controles (0,819 e 0,857, respectivamente; P=0,5605), com prevalência do genótipo B1/B1 nos pacientes (65,9 por cento) e controles (71,4 por cento; P=0,6639), seguido de B1/B2 (31,8; 28,6 por cento, respectivamente; P=0,8268). Em conclusão, DAP, independente do tipo de lesão obstrutiva ou aneurismática, apresenta-se indiferente ao polimorfismo Bcl I do fibrinogênio, portanto, sem influência dos alelos B1 e B2 para fibrinogênio e seus respectivos genótipos na doença.

The objective of this study was to analyze the frequencies of thealleles and genotypes of the gene encoder of the fibrinogen bchainin patients suffering from peripheral artery disease. A totalof 62 male Caucasoid patients with ages varying from 38 to 79years old were studied. All the patients had clinical symptoms ofperipheral artery disease, which was later confirmed byangiography. Forty of the patients had atheroscleroticobstructions of the iliac, femoral or carotid arteries and 22 sufferedfrom aneurysms of the thoracic, abdominal or thoracoabdominalaortas. All the patients were submitted to surgery. A controlgroup was formed of 62 individuals, with ages ranging from 43to 80 years old, without clinical histories or alterations in theirclinical examinations of peripheral artery disease. Individualswith renal disease, liver disease or diabetes mellitus wereexcluded. Analysis of the fibrinogen b-chain was performed usingpolymerase chain reaction and restriction fragment lengthpolymorphism with Bcl I endonuclease. Three genotypes, B1/B1,B1/B2 and B2/B2 were identified. Statistical analysis was madeusing the Fisher Exact test, odds ratio, Kruskal-Wallis test andvariance analysis (ANOVA). A p-value = 0.05 was consideredsignificant. The B1 allele was the most prevalent in both patientsand the control group (0.819 and 0.857, respectively), withprevalence of the B1/B1 genotype in patients and controls (65.9%vs. 71.4% respectively), followed by B1/B2 (31.8% vs. 28.6%respectively). No significant difference was observed in relationto the Bcl I polymorphisms of the fibrinogen b-chain andobstructive and aneurysmal peripheral artery disease. Inconclusion, the B1 and B2 polymorphisms of the fibrinogen bchain and teir respective genotypes do not have any influence in peripheral artery disease.

Influence of the polymorphism of apolipoprotein E in cerebral vascular disease

The genetic heterogeneity of apolipoprotein E (apo E) has been associated with lipid profile and atherothrombotic stroke, however this association remains inconclusive. OBJECTIVE: To evaluate the relationship between the isoforms of apo E and atherothrombotic stroke, by ascertaining the frequency of its alleles and genotypes associated with the lipid profile in patients with stroke. METHOD: A total of 207 individuals were divided into two groups, consisting of 107 patients with stroke and 100 individuals without clinical symptoms of the disease. Blood samples were taken from patients and controls for molecular investigation of the apo E (epsilon2, epsilon3 and epsilon4 alleles) for the analysis of the lipid profile. RESULTS: The epsilon3 allele was the most common and its prevalence was significantly higher in patients (0.93) compared to the controls (0.86; p=0.024). The epsilon2 allele was rarely seen specifically in patients (0.02 versus 0.05 in controls, p=0.191). The epsilon4 allele was not associated with stroke showing a reduced frequency in patients (0.05) when compared to controls (0.09; p=0.011). Although higher average levels of lipid profile were found in patients when compared to controls, with statistical significance for the values of total cholesterol (TC) (203.6mg/dL±57.98 and 181.9mg/dL±68.47 respectively; p=0.003) and low-density lipoprotein cholesterol (LDLc) (131.4mg/dL±52.60 and 116mg/dL±56.38, respectively; p=0.014), these were independent of the presence of the epsilon4 allele. In control group the higher TC and LDLc values occurred in the absence of the epsilon4 allele, confirming the conflicting effect of the alleles of apo E on the plasmatic lipids and atherothrombotic stroke. CONCLUSION: The isoforms of apo E cannot be regarded as an isolated risk factor for stroke and do not show association with lipid profile in this study