Susceptible Genetic Variants And Biomarkers Of Asymptomatic Intracranial And Extracranial Arterial Stenosis In Hypertensive Patients

Aim: Intracranial and extracranial arterial stenosis(IECAS)plays a key role in the etiology of ischemic stroke and is especially prevalent in hypertension patients.It is believed that genetic factor contributes to the pathogenesis of IECAS.Genome-wide association studies have identified several loci associated with large artery atherosclerotic stroke.Our previous work has also found IECAS specific risk factors including Lp-pla2,homocysteine and brachial-ankle pulse wave velocity(ba PWV).However,whether loci identified by GWAS or related to aforementioned risk factors affecting the formation of IECAS,the premature lesion of stroke,remain poorly understood.In the current study,we evaluated the association of asymptomatic IECAS and loci found by GWAS or related to ATP2B1(ba PWV),MTHFR(homocysteine)and PLA2G7(lp-pla2)gene.We also sought IECAS relevant clinical markers to work synergistically with significant loci in order to promote early recognition and personalized medicine of high risk patients.Methods: We selected a total of 951 primary hypertension patients aged 50 years or older and without prior stroke from hypertension patinets managed in Xinzhuang community hospital.These patients underwent brain CTA from the lateral ventricle down to the arch of the aorta to identify the presence,extent,and lesion number of IECAS.Laboratory test of blood and urine and blood pressure measuring were done.We also collected clinical information regarding smoking and drinking history,as well as history of cardiovascular disease and drug prescription by clinical interview.According to stenosis extent,stenosis was classified into no stenosis(0%),mild(1-29%),moderate(30-69%)and severe(70-100%).Patients were grouped into no stenosis(NS),isolated intracranial arterial stenosis(ICS),isolated extracranial arterial stenosis(ECS)and concurrent intracranial and extracranial arterial stenosis group(IECS)based on their stenosis location.We extracted DNA from whole blood and genotyped SNPs of ATP2B1,MTHFR,PLA2G7,ABO,CDKN2B-AS1,PDE4 D,PTCSC3 and some other genes.The analysis on the association of IECAS and SNPs were done in 899 participants with complete clinical data.We also evaluated the association of intracranial atherosclerosis with urine albumin-creatinine ratio.Results: Part 1,Association of asymptomatic IECAS and cardiovascular disease-related SNPs: The proportion of NS,ICS,ECS and IECS were 46.7%,22.0%,15.4% and 15.9%.Stenosis arteries were mainly located in the intracranial segment of internal carotid artery.Patients with stenosis were significantly different with NS group in cardiovascular risk factors,especially in patients with IECS.Among 27 genotyped SNPs,only rs17249754 and rs1401982 of ATP2B1 gene were significantly associated with IECS after Bonferroni correction for multiple testing(Dominant: p values all <0.001).This association remained significant after adjustment of age,sex,blood pressure,blood lipid,diabetes,smoking history and family history of cardiovascular disease(dominant OR 0.42[0.27-0.66],p=0.0001 and OR 0.46[0.29-0.71],p=0.0004).The two SNPs were also associated with stenosis lesion number and stenosis extent.Part 2,Association of asymptomatic IECAS and SNPs related to large artery atherosclerotic ischemic stroke: rs1333047,rs1333049 and rs2383207 of 9p21,rs702553 and rs918592 of PDE4 D,rs2107595 of HDAC9,rs2081015 of GALNT10 were associated with one or more phenotypes of ECS,IECS,and moderate-to-severe stenosis.The associations lost significance after Bonferroni correction.Both allelic and weighted genetic risk scores showed no significant association with IECAS.Part 3,association of asymptomatic intracranial stenosis(ICAS)and urine albumincreatinine ratio(ACR): A total of 889 participants were included in the analysis.The ACR level was 27.2(Interquartile range 15.7-50.9)mg/g in the whole population and was higher in patients with ICAS.A doubling of ACR increased 11% ICAS risk(95% CI 1-1.23,p=0.044).Patients with ACR>=30mg/g had 65% increased ICAS risk(95% CI 1.21-2.27,p=0.0002),more stenosis lesions and severer stenosis extent.Subgroup analysis showed the association remained significant in patients who were male,aged 65 years or olrder,and non-diabetic.Conclusions: rs17249754 and rs1401982 of ATP2B1 were associated with asymptomatic IECS.Variants of 9p21,PDE4 D,HDAC9 and GALNT10 might be associated with IECAS.Future study should be performed to verify the results in a larger population and focus on elucidating pathogenic mechanism.ACR was associated with asymptomatic ICAS and might help in the early prevention and treatment of ICAS.