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ПОЛИМОРФИЗМ ГЕНОВ СОСУДИСТОГО ТОНУСА И ЭНДОТЕЛИАЛЬНОЙ ДИСФУНКЦИИ ПРИ ПРЕЭКЛАМПСИИ
Нишанова Фируза Пулатовна
Республиканский специализированный научно-практический медицинский центр
акушерства и гинекологии
Полиморфизм пяти генов «эндотелиальной дисфункции» и «сосудистого тонуса»: эндотелиальной синтазы оксида азота NOS3, альдостеронсинтазы, рецептора ангиотензина II и гуанин-связывающего белка изучали в контрольной выборке из 78 пациентов с диагнозом преэклампсия и 29 здоровых людей из контрольной группы. Результаты данного исследования демонстрируют наличие в гене NOS3 маркеров риска при развитии ПЭ. Генетические ассоциации, выявленные в данном исследовании, могут быть использованы в качестве генетических маркеров предрасположенности к ПЭ, что позволит своевременно выявить пациентов группы риска, разработать правильное лечение и профилактические мероприятия.
Ключевые слова: преэклампсия, полиморфизм генов, NOS3, рецептор ангиотензина.
VASCULAR TONE AND ENDOTHELIAL DYSFUNCTION GENES POLYMORPHISM IN PREECLAMPSIA
Five genes polymorphism of «endothelial dysfunction» and «vascular tone: endothelial nitric oxide synthase NOS3, aldosterone synthase, angiotensin II receptor and guanine-binding protein were studied in case-controlled sample of 78 patients diagnosed preeclampsia and 29 healthy controls. Results of this study demonstrate the presence in NOS3 gene risk and protective markers in the development of PE. Genetic associations performed in this study may be used as genetic markers of PE susceptibility, which will allow timely group risk patients, to work out correct treatment, and preventive measures.
Key words: preeclampsia, gene polymorphism, NOS3, angiotensin receptor.
PREEKLAMPSIYADA QON TOMIRLAR TONUSI VA ENDOTELIAL DISFUNKSIYA GENLARIPOLIMORFIZMI
Beshta gen polimorfizmi «endotelial disfunktsiya» va «qon tomir tonusi: endotelial nitrat oksidi sintaza NOS3, aldosteron sintaza, angiotenzin II retseptorlari va guaninni bog'laydigan oqsillar, 78 ta preeklampsi tashxisi qo'yilgan va sog'lom bemorlarda o 'rganildi.
Ushbu tadqiqotda o'tkazilgan genetik assotsiatsiyalar PE sezgirligining genetik belgilari sifatida ishlatilishi mumkin, bu xavf guruhidagi bemorlarga o 'z vaqtida to 'g 'ri davolash va profilaktika choralarini ishlab chiqishga imkon beradi.
Kalit so 'zlar: preeklampsiya, gen polimorfizmi, NOS3, angiotenzin retseptorlari.
Background. Preeclampsia (PE), a major cause of maternal and neonatal morbidity and mortality, affects 5% to 7% of pregnancies in the Western world but can have up to 3-fold greater incidence in other geographic areas with different ethnic or social characteristics. [1]. More than 12,000 women suffer from preeclampsia in Uzbekistan each year, which is the second reason of maternal mortality after bleeding according to data of Ob&Gyn Republican Specialized Scientific and Practical Medical Center of Uzbekistan (RSSRMC) [6].
Preeclampsia is thought to have an important genetic component [2]. Several studies have reported associations between preeclampsia and polymorphisms of various genes [3,4,5].
Objective of the study was to examine genetic polymorphisms associated with the risk of hypertension and endothelial dysfunction markers in Uzbek population.
Materials and methods. A total of 78 cases of preeclampsia patients and 26 healthy pregnant female controls were recruited from the outpatient and inpatient sections RSSPC of Ob&Gyn. PE were diagnosed according to international protocols. All controls had a normal pregnancy without complications, hypertension and proteinuria. We used study questionnaire which was reviewed by Executive committee of our center. Genomic DNA was extracted from the white blood cells of the patients' blood samples using the standard alcohol-saline method. Genotyping was performed by amplifying the corresponding regions of the genome by qPCR methods (DT-96 DNA technology, RF) and pyrosequencing (PyroMark Q24, Qiagen, Germany) using reagents PyroMark Gold Q24 (Qiagen, Germany) and the PCR kits.
Statistical analyses were performed using the statistical packages «SPSS 13», «PLINK» and «Haploview 4.2», formation of haplotypes and estimation their association with APS syndrome was carried out using the program «THESIAS» (version 2.0). Genotype distribution of studied polymorphisms tested for compliance from the Hardy-Weinberg equilibrium using Fisher's exact test (Weir, 1995). The x2 test with Ieyts' correction or Fisher's test were employed to compare allele and genotype frequencies between analyzed groups. The 95% confidence intervals (CI) and odds ratio (OR) were also estimated. Differences were considered statistically significant at P <0.05.
Results and discussion: Polymorphisms of 4 genes which are responsible in the regulation of vascular tone were investigated: angiotensinogen (AGT) rs4762 and rs699, angiotensin II receptor type 1 (AGTR1) rs5186 and angiotensin II receptor type 2 (AGTR2) rs1403543 (Table 1).
Table 1.
SNP ol ' genes - candic ates of PE
Gen Gen localization Polymorphism db SNP
AGT(Angiotensinogen) 1q42-q43 Thr174Met rs4762
AGT(Angiotensinogen) 1q42-q43 Met235Thr rs699
AGTR1(Angiotensinogen II receptor type 1) 3q21-q25 A1166C rs5186
AGTR2 (Angiotensinogen II receptor type 2) Xq23 G1675A rs1403543
Genotype distribution of all 4 polymorphisms was in Hardy-Weinberg equilibrium in both groups (Table 2).
Distribution of allele frequencies and genotypes polymorphisms of rs4762, rs699, rs5186, rs1403543 gene regulators of vascular tone in PE and control groups revealed risk and protective markers for this disease (Table 3). Thus, relative risk allele T and TT genotype polymorphism rs4762 were 2.69 (P = 0.005) and 3,1 respectively, (P = 0.02); while G allele (OR = 0.37; P = 0.005) and GG genotype (OR = 0.29; P = 0.02) of this polymorphism can be regarded as a protective marker in the development of this pathology.
As for rs4762 polymorphism of AGT gene no significant, whereas T allele polymorphism rs699 was thought to be risky in the development of PE (OR =1.9; P = 0.0033). Thus, relative risk of T allele was 2.74 (P = 0.001) and TT genotype - 3.37 (P = 0.01).
As for rs5186, rs1403543 polymorphism, no significant differences in the genotype distribution or allele frequencies.
Table 2.
Hardy-Weinberg's test indexes in stut y groups.
Chrom SNP Group A1 A2 X2 p
1 rs4762 1 C T 0.23 0.63
1 rs4762 2 C T 0.64 0.24
1 rs699 1 T C 1.87 0.17
1 rs699 2 T C 0.73 0.39
3 rs5186 1 A C 0.01 0.92
3 rs5186 2 A C 1.87 0.17
X rs1403543 1 G A 0.2 0.66
X rs1403543 2 G A 2.94 0.09
Note: group 1- case; 2 - control; A1- dominant allele, A2 - recessive allele
Linkage disequilibrium between the polymorphic gene loci AGT (r2 = 0.937; D '= 0.89; P = 0.0000) was observed in PE patients and control group. Comparison of haplotype frequencies between patients with PE and the control group showed a risky haplotype CC (64% vs 3.5% in the control group, x2 = 6.66, p = 0.009, OR = 1.57, CI: 1.04-2.36) and the protective haplotype TC (x2 = 5.8, p = 0.015, OR = 0,29; CI: 0,22-0,42). There were no statistically significant differences for other haplotypes (Figure 1).
Five polymorphisms of «endothelial dysfunction» and «vascular tone» were examined in this study: endothelial nitric oxide synthase NOS3: -786T> C (rs2070744) and 894 G> T (rs1799983); aldosterone synthase CYP11B2 C-344T (rs1799998); angiotensin II receptor type 1 AGTR1 (rs5186) and guanine-binding protein GNB3 C825T (rs5443).
There was disequilibrium on Hardy-Weinberg's test in 2 polymorphism (rs1799983) (P=0.04) h rs5443 (P=0.005) among estimated 5 polymorphism only in control group.
Figure 1.
Distribution of haplotype rs4762 and rs699 polymorphism frequencies in groups
Distribution of allele frequencies of genotypes for polymorphisms rs1799983, rs1799998, rs5443 genes of «endothelial dysfunction» and «vascular tone» in PE and in control group revealed presence of risk and protective markers for this disease. Thus, the
relative risk of the G allele and GG genotype polymorphism rs1799983 amounted to 2,55 (P = 0.01) and 4,34 (P <0.01); while T allele (OR = 0.39; P = 0.01) of the polymorphism can be regarded as a protective marker in the development of this pathology.
We have also found a significant increase in the frequency of mutant allele T polymorphism rs1799998 gene of aldosterone synthase (OR = 1.92); P = 0.04 in PE women compared with physiological pregnancy. Frequencies of allele and genotype polymorphisms of rs2070744, rs5186 and rs5443 statistically have no difference in this study.
Comparison of haplotype frequencies of polymorphisms rs2070744 and rs 1799983 between patients with PE and the control group showed a risky haplotype TG (v2 = 4.66, P =
0.02. OR = 1.7) and the protective haplotype CT (v2 = 5.8, P = 0.01, OR = 0.21). For other haplotypes statistically significant differences were not found.
Thus, results of this study demonstrate the presence in NOS3 gene risk (G allele / GG genotype) and protective (T allele) markers in the development of PE. Mutant T allele polymorphism rs1799998 gene of aldosterone synthase carrier is also associated with the risk of PE. Loci haplotype analysis revealed the presence of risk TG (P = 0.02, OR = 1.7) and protective CT (P = 0.015, OR = 0.21) haplotypes in the development of PE. There were no significant associations in polymorphism rs2070744, rs5186 and rs5443.
Conclusion: Polymorphisms of «endothelial dysfunction» and «vascular tone» genes have a great value in the development of hypertensive disorders in pregnancy. Genetic associations performed in this study may be used as genetic markers of PE susceptibility, which will allow timely group risk patients, to work out correct treatment, and preventive measures.
REFERENCES
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