Effect of RAS Polymorphism on Essential Blood Pressure

Effect of reticular activating dust Polymorphism on all- essential(a) Blood PressurePharmacogenetic Association of RAS Polymorphism on Essential Blood Pressure in Relation to Enalapril/Lisinopril among Malay male person newly diagnosed hypertensivesAbstractObjective It has been suggested that genetic backgrounds, which have an association with internal hypertension, may also determine the responsiveness to ACE inhibitor. We determined the association of angiotensin-converting enzyme (I/D, G2350A), angiotensinogen (M235T, T174M and A-6G) and renin (Bg/I and Mbo/I) gene polymorphisms with essential hypertension and the relationship between genetic form of interest and high fund pressure response to ACE inhibitor (enalapril, lisinopril) in patients with essential hypertension subjects from Seremban, Malaysia.Methods A newly hypertensive Malay male cosmos (n=142) was recruited for a mono-trophyah1 pharmacogenetic study. Hypertensive patients were treated with ACEI drugs, particula rly enalapril or lisinopril alone. We differentiated between those who controlled their HT with those who did non. Each groups characteristics were comp ared to determine the risk of non-controlled HT associated with RAS polymorphisms by adjusting for different variables.Results Statistically significant associations of I, G, T and M alleles were observed with essential hypertension in I/D, G2350A, M235T, and T175M. The decrease in systolic source pressure and diastolic blood pressure after 24 weeks of treatment of the patients carrying II, GG, and TT genotypes was greater than the groups carrying DD, AA, MM and MM genotypes. In contrast, no significant variety was shown between renin gene polymorphisms (Bg/I and MboI).Conclusions Although this study shows a possible association of polymorphisms of RAAS genesah2 with the risk of non-controlled HT in ACEI-treated patients and indicates the importance of all components in this system in modulate HT, it needs to be replicated in ot her data sources.Keywords Essential hypertension renin-angiotensin-aldosterone system single-nucleotide polymorphism ACE inhibitors pharmacogeneticINTRODUCTIONEssential hypertension (EH) is an increasingly important medical and public health issue 1. In Malaysia, the National Health and Morbidity Survey (NHMS) 2013 has shown that the prevalence of hypertension in adults 18 years increase from 33.2% in 2006 to 35.7% in 2013 2. Furthermore, the prevalence increase from 42.6% to 43.5% for those 30 years old. Unfortunately, 60.6% of total hypertensives were undiagnosed 3. These poor rates of high blood pressure (BP) control are not explained by the lack of treatment, as one study estimated approximately 30% of treated hypertensive patients take one antihypertensive drug, 40% take both antihypertensive drugs and 30% take tether or more antihypertensive drugs 4. These data suggest that the gratuity trial and error approach for high blood pressure man daysment is suboptimal, and alterna tive approaches for identifying the optimal antihypertensive regimen in a specific patient are needed. Using genetic make-up of an single along with the association between single-nucleotide polymorphisms (SNPs) and angiotensin-converting enzyme (ACE) inhibitors for hypertensive response offers a new preventive approach to lower adverse drug interaction risk.A renin-angiotensin system (RAS) is an important component of blood pressure regulation, and it has been suspected to be involved in hypertension 5. Moreover, the major active peptide of the RAS is angiotensin II. Produced from the precursor molecule, angiotensinogen (AGT), via an enzyme cascade down involving ACE enzyme, angiotensin II exerts numerous effects on the homeostatic regulation of blood pressure, the vast majority of which are mediated via the angiotensin II type 1 receptor (AT1R) 6.The presence of polymorphisms in the ACE, AGT and renin (REN) genes of the RAS has been associated with adverse EH changes in several studies 7,8,9. For example, the insertion/deletion (I/D) polymorphisms of the ACE gene have been associated with increased blood pressure, urinary albumin excretion (UAE) and target-organ damage in hypertensive patients 10. Moreover, ACE G2350A gene polymorphisms in exon 17 were reported as a remarkable genetic variant mostly associated through hypertension with an average increase of 3.2 mmHg in SBP by having the G allele 11.It has been reported that the presence of A-6G polymorphism of AGT gene among Chinese hypertensives increased body weight gain in hypertensive patients 12. The Mb/I and Bg/I polymorphisms of the REN gene have been associated with hypertension, left ventricular hypertrophy, aortic stiffness and exaggerated vasoconstriction additionally, the Bg/I polymorphism in the same gene appears to confer protection against the development of microalbuminuria in patients with hypertension 13.The purpose of the present study was to evaluate the impact of four RAS gene polymor phisms on the antihypertensive response in newly detected hypertensives receiving two ACEIs (enalapril and lisinopril). The polymorphisms investigated were A-6G, the A for G substitution of the AGT gene 6 nucleotides upstream from the start site the ACE I/D polymorphism corresponding to an insertion or deletion of a 287bp alu repeat and two polymorphisms of the REN gene, Bg/I and MboI and both in the coding area of intron 9. There are compelling reasons hypothesizing that variations in genes of the system may be predictive of variations in BP response. Therefore, genetic variation of the RAS has been investigated in relation to antihypertensive response to ACE inhibitors in various population and dosage (Table 1) as the most common lowering BP agent in Malaysia 14 however, previously publications have had somewhat conflicting results elsewhere 15-19.We hypothesized those genetic polymorphisms in RAS genes, including ACE I/D, G2350A, AGT M235T, T174M, A-6G along with REN MboI and Bg/ I were associated with the incidence of EHT. Therefore, the aim of this pharmacogenetic study was to investigate the association between seven RAS gene polymorphisms of interest among 142 newly diagnosed Malay male hypertensives that never took BP medications. They were treated once daily for 24 weeks with 20 mg of enalapril or lisinopril.MATERIAL AND METHODSPatient PopulationsMalay male patients 18 years of age with three-generation Malay family who were newly diagnosed with essential mild-to-moderate hypertension were collected from clinics for non-communicable disease Seremban, Malaysia. The information includes age (25-60 years old), onset (25-60 years old), systolic BP 140 mmHg and a diastolic BP 90 mmHg on 2 consecutive visits for those untreated, absence of secondary forms of hypertension. Subjects with a history of diabetes mellitus, renal failure and major infectious disease were excluded. They had no metabolic or endocrine disorder, as well as any acute illness. They we re not on any antihypertensive treatment and were drug-naive patients. Written informed swallow was obtained from each patient before being included in the clinical trial, and patients identity was kept strictly confidential. A specific concur form was requested for genetic testing permission.BLOOD PRESSURE REDUCTION PATTERNLifestyle ModificationFor patients, lifestyle modification for a period of three months was advised. The patients were seen three times during this period to assess the efficacy of the non-pharmacological management including weight loss, regular exercise, and ingestion of a high-fiber, low-fat, and low-salt diet.Follow-up Mon-trophyah3 ManagementDispensed ACEIs (lisinopril or enalapril) on the same date for individuals have recorded.Each patient received lisinopril or enalapril (20 mg, once daily) for 24 weeks on a regular basis. Patients BP was mensural using the same device and protocol follow-up visits were made 12 times (once per two weeks). Of the 152 pa tients, 10 lost to the follow-up along monitoring due to relocation, travelling and/or change of medication. Eventually 142 hypertensives (92.6%) completed the study. This subsample was divided into two groups individuals whose HT was not controlled as the non-responded (n=35), and individuals whose HT was under control as the responded (n=107). Figure 1 presents how responded and non-responded HT groups are categorized.Fig. 1. The flowchart of sample collection.Genotyping proceduresA blood sample was taken in two separate tubes one was used for colorimetric analysis of total cholesterol (TC), high density lipid profile (HDL), low density lipid profile (LDL), triacylglycerol (TG) and fasting glucose (FBG) using Diays Commercial Kits (Diagnostic System, GmBH, D66559 Holzheim, Germany), and the other test tube contained venous blood samples collected on EDTA was subjected to DNA extraction, which was obtained from individuals in the morning after a minimum of 8 hours fasting at the time of randomization. Eventually, the samples were stored at -20C for further molecular and biochemical analysis.DNAs were extracted from 5 mL blood samples as explained elsewhere 20. ACE I/D polymorphism was genotyped using DNA expansion with oligonucleotides as described elsewhere 21. For ACE G2350A, DNA amplification followed the approach by Zhu et al. 22. Reactions were conducted using DNA amplification in a final account book of 25 mL containing 20 pmol of each primer, 0.4 mmol/L of each deoxynucleotide triphosphate (dNTP), 2 mmol/L of MgCl2, 1XTaq buffer and one unit of NEB Taq DNA polymerase (New England Biolabs, Beverly, MA, USA). The PCR cycling conditions were carried pop in an iCycler machine (BioRad Laboratories, Hercules, CA, USA). Were chosenah4 for genotyping using the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) approach, and the details are presented in Table 2. Eventually, DNA fragments were stain in ethidium bromide and visual ized by Alpha Imager (Alpha Innotech, San Leandro, CA, USA) under ultraviolet (UV) light.Statistical AnalysisSPSS 20 statistical package (SPSS, Chicago, USA) was used for analysis. Allele frequencies were metrical from the genotypes of all subjects. Hardy-Weinberg equilibrium (HWE) was assessed by 2 analysis. Continuous data are presented as mean SD. Differences between groups were tested by an 2 test for soft parameters and by one-way analysis of variance (ANOVA). All tests were two-tailed and the values of p