The Relationship Between Telomere Length,Mitochondrial DNA Copy Number Of Peripheral Blood And Essential Hypertension

Objective:1.To explore the related factors of telomere length and the relationship between telomere length and essential hypertension;2.To study the relationship between mitochondrial DNA copy number,the relevant influence factors of mitochondrial DNA copy number and essential hypertension;3.To elucidate the interaction between telomere length,mitochondrial DNA copy number and related factors on essential hypertension.Methods:Two communities were randomly selected by multi-stage sampling method.A case control study was conducted in the two communities,and the residents over the age of 18 years were selected as respondents.According to the inclusion and exclusion criteria,285 healthy residents were selected as the control group,and 304 residents with essential hypertension were selected as the case group.The information about general demographic characteristics and life behavior habits of the subjects were collected through face-to-face questionnaire surveys.At the same time,biological samples were collected.Real-time quantitative PCR was used to detect TL and mtDNA-CN levels of peripheral blood;enzyme linked immunosorbent assay was used to detect urine 8-OHdG levels;sarcosine oxidase method was used to determine urine creatinine levels;serum MDA levels were measured by thiobarbital acid method;serum SOD activity was detected by xanthine oxidase-hydroxylamine method;serum GSH-Px activity was measured by enzymatic glutathione consumption method.SPSS 23.0 was used to analyzethe data.T-test,Chi-square test,non-parametric test and ANOVA were to analyze the corresponding data.Pearson correlation or Spearman rank correlation were carried out to analyze the correlation between indicators,multivariate logistic regression and principal component logistic regression were used to explore the relationship between factors and hypertension,additive and multiplicative interaction method was performed to analyze the association between TL,mtDNA-CN and related factors as well as their interaction on hypertension.P<0.05 was considered statistically significant.Results:1.A total of 589 residents were included in this study.Of these,304 were essential hypertension subjects and 285 were healthy controls.The differences between control group and case group in terms of age,BMI,education status,famliy monthly income per capita,family history of hypertension,SBP and DBP were statistically significant(P<0.05).There was no statistically significant difference in gender,marital status,smoking and alcohol drinking(P>0.05).2.The TL of case group was shorter than that of the control group(P=0.001),the level of 8-OHdG was higher than that of the control group(P<0.001),and the level of MDA was lower than that of the control group(P=0.023),but there were no statistically significant difference in the mtDNA-CN and activity of SOD and GSH-Px(P>0.05).3.Explore related factors of TL and mtDNA-CN(1)After stratifying each factor and comparing TL,it was found that age,gender,BMI,education status,famliy monthly income per capita,family history of hypertension,smoking,alcohol drinking and oxidative stress levels may influence the TL;negatively correlation was found between TL and 8-OHdG,MDA,SBP and age,respectively.(2)Use the same methods to comparing mtDNA-CN,it was found that age,famliy monthly income per capita,family history of hypertension and oxidative stress levels may affect mtDNA-CN;positively correlation was found between mtDNA-CN and MDA levels,negatively correlation was found between mtDNA-CN and age.4.Unconditional logistic and principal component logistic regression found that TL and mtDNA-CN were the influencing factors of hypertension,and shorter TL,lower mtDNA-CN were the risk factors of hypertension;we also found that age(OR=1.057,95%CI: 1.036~1.079),higher BMI(OR=1.169,95%CI: 1.104~1.237),famliy monthly income per capita(OR=0.725,95%CI: 0.567~0.926),family history of hypertension(OR=3.518,95%CI: 2.094~5.911),higher 8-OHdG(OR=1.430,95%CI: 1.311~1.560),SOD and GSH-Px might be contributing factors to hypertension.5.Additive and multiplicative interaction analysis found that the multiply interactions between TL and age(OR=1.606,95%CI: 1.316~1.960),TL and higher8-OHdG(OR=1.821,95%CI: 1.532~2.165)were significant on hypertension,respectively.We also found that mtDNA-CN and age(OR=1.450,95%CI: 1.207~1.743),mtDNA-CN and family history of hypertension(OR=1.419,95%CI: 1.152~1.748)have multiply interactions on hypertension,respectively.But TL and mtDNA-CN did not present interaction on hypertension.Conclusions:1.There are significant differences of TL,age,and oxidative stress levels between hypertension group and control group.2.The changes of age and oxidative stress levels may influence the TL and mtDNA-CN.3.Shorter TL,lower mtDNA-CN are independently associated with hypertension.There might be interaction effect between shorter telomere length and age,shorter telomere length and higher 8-OHdG on the risk of hypertension in this population,respectively.The same effects could be found between lower mtDNA-CN and age,lower mtDNA-CN and family history of hypertension.These findings provide a basis for revealing the pathogenesis of hypertension.