ABSTRACT
BACKGROUND: Polymorphisms in the gene encoding methylenetetrahydrofolate reductase (MTHFR) have been investigated as risk factors for microvascular complications of diabetes; however, simultaneous analysis of these polymorphisms and the methylation pattern of the gene has never been conducted. The objective of the present study was to evaluate the simultaneous relationship between MTHFR methylation and MTHFR C6TT7 and A1298C polymorphisms with metabolic, inflammatory and oxidative stress parameters related to microvascular complications, diabetic retinopathy (DR) and diabetic nephropathy (DN) in diabetic patients. METHODS: A total of 107 patients who were diagnosed in the previous 5 to 10 years were recruited and divided into groups with complications (DR and/or DN) or without complications. Methylation analysis of the gene promoter was conducted using the MSP technique, and analysis of the A1298C and C677T polymorphisms was conducted using the restriction fragment length polymorphism (RFLP) assay. Microalbuminuria was determined using urine samples, and other analytes of interest were determined in blood samples using commercial kits. The Mann-Whitney and Chi square statistical tests were used with significance considered at p < 0.05. RESULTS: Subjects with a hypermethylated profile and the 1298AA genotype showed the highest levels of blood glucose (p = 0.03), total cholesterol (p = 0.0001) and LDL cholesterol (p = 0.0006). The same profile was associated with higher levels of HbA1c (p = 0.025), glycemia (p = 0.04) and total cholesterol (0.004) in the control group and total cholesterol (p = 0.005) and LDL cholesterol (p = 0.002) in the complications group. Serum creatinine was higher in subjects in the hypermethylated group with the genotype 677CC only in the control group (p = 0.0020). The methylated profile in presence of 677CC + 1298AA and the 677CT/TT +1298AA haplotypes showed higher levels of total cholesterol (p = 0.0024; 0.0031) and LDL cholesterol (p = 0.0060; 0.0125) than 1298AC/CC carriers. The fasting glycemia was higher in hypermethylated profile in the presence of 677CC/1298AA haplotype (p = 0.0077). CONCLUSION: The hypermethylated methylation profile associated with the 1298AA genotype appeared to be connected to higher values of glycemia, total cholesterol and LDL cholesterol.
Subject(s)
DNA Methylation , Diabetic Nephropathies/genetics , Diabetic Retinopathy/genetics , MicroRNAs/genetics , Promoter Regions, Genetic/genetics , Adult , Aged , Case-Control Studies , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/pathology , Diabetic Nephropathies/pathology , Diabetic Retinopathy/pathology , Disease Progression , Female , Gene Expression Profiling , Humans , Male , Middle Aged , TranscriptomeABSTRACT
A variação biológica é definida como a variação natural, de ocorrência fisiológica, independente das variáveis pré-analíticas. A resposta individual aos diferentes estímulos a que o organismo é submetido resulta numa amplitude de variação biológica que oscila entre os indivíduos. Esta amplitude de variação deve ser quantificada a fim de auxiliar na interpretação dos resultados laboratoriais. O objetivo deste projeto foi verificar a variabilidade biológica na determinação de lipídeos (colesterol total, HDL colesterol, LDL colesterol e triglicerídeos) em indivíduos saudáveis. Foram convidados a participar do projeto 10 indivíduos saudáveis que foram submetidos a 10 coletas de sangue consecutivas. Após as coletas, o soro foi analisado em equipamento automatizado Cobas Mira" Marca Roche utilizando kits comerciais. As variabilidades biológicas individuais e totais encontradas foram semelhantes às descritas previamente na literatura. As menores variabilidades foram as das determinações de colesterol total (6,3%) e HDL-c (4,9%), enquanto que os triglicerídeos apresentaram o maior índice (25%). O coeficiente de variação biológica dos analitos foi superior à mediana descrita na literatura em alguns indivíduos. Nova amostra deve ser analisada quando existir discrepância entre as interpretações clínicas ou biológicas das duas amostras.
Biological variability is defined as a natural variation, with physiological occurence, independent of pre-analytical factors. The individual answer to the different stimulations to which the organism is subjected to results in degrees of biological variation that are change between subjects. This degree of variation must be quantified to help the laboratory results interpretation. The objective of this project was verify the biological variability in lipids determinations (total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides) in healthy subjects. Ten healthy individuals participated in this projetct. The samples were collected by venopunction, ten times, in three consecutive weeks. The serum obtained was analysed in automatized equipment Cobas Mira" (Roche) using commercial kits. Both individual and total variability coefficients found were similar to the literature. Total cholesterol (6.3%) and HDL-cholesterol (4.9%) showed the lowest variabilities, whereas triglycerides presented the biggest index (25%). In some patients the variation coefficient for any analyte was superior than the range previously described in the literature. New sample analyses must be performed when there is some discrepancy in clinical or biological interpretation between results.
