Article Text
Abstract
Background Kidney diseases are the common cause of secondary hypertension in children, which predetermines dismal prognosis of the primary disease. Heredity is one of the main causes for arterial hypertension development. The AGTR1 gene encodes a protein receptor for angiotensin II, 1-type, which is involved in the regulation of vascular tone and blood pressure. The purpose of our study was to identify the particular circadian violations in blood pressure in children with glomerulonephritis and secondary hypertension depending on the variant of ARTR1 gene.
Methods The study group included 35 children aged 10.46±2.93 years with glomerulonephritis and hypertension. Circadian monitoring of arterial pressure was carried out with 15 min intervals during the day and 30 min intervals during the night. The variant of AGTR1 gene (A1166C polymorphism; rs5186) was determined using polymerase chain reaction (PCR). DNAs were extracted from blood samples. DNA fragments length analysis after amplification and restriction was carried out in 7% acrylamide gel. Statistical analysis was performed using STATISTICA, version 10.0 StatSoft Inc, USA. Quantitative characteristics are presented by median with 25 and 75 percentiles. The Mann-Whitney test was used to analyse the differences between groups. The differences were considered statistically significant at 5% significance level.
Results We analysed the circadian indicators of blood pressure in children with glomerulonephritis and hypertension depending on the variant of the AGTR1 gene. We found statistically significant differences in the morning rise rate of systolic blood pressure and diastolic blood pressure variability in children with different genotypes. The morning rise rate of systolic blood pressure in the group of children with the C-allele was significantly higher (p=0,048) than in the group of children without C-allele – 14,4 mmHg (9,1–20,6) and 8,7 mmHg (7,1–12,6) respectively. The diastolic blood pressure variability during the daytime in the group of children with the C-allele is also significantly higher (p=0,019) than in the group of children without the C-allele – 10 mmHg (8,8–11) and 8 mmHg (7,5 -9) respectively.
Conclusions The unfavourable C-allele of AGTR1 gene contributes to the circadian changes in the indicators of blood pressure in children with chronic glomerulonephritis and secondary hypertension.