The Study On The Effect Of PAH Metabolites In Urine On Blood Lipids

Objective:1.To assess the damage to oxidative stress and inflammatory mediators by PAH metabolites by analyzing the relationship between urinary PAH metabolites,8-OHdG and cytokines,and provide evidence for screening markers of oxidative stress and inflammatory mediators when exposed to PAHs.2.To assess the influence of PAH metabolites on blood lipids by analyzing the relationship between urinary PAH metabolites and blood lipids.At the same time,mediation analysis was used to explore oxidative stress and inflammatory mediators in the mediating process of PAH metabolites affecting blood lipids,and provide evidence for the mechanism of blood lipids change caused by PAHs exposure.Methods:In this panel study,112 healthy elderly volunteers aged over 60 years were selected from two communities in Tianjin to participate in the study by systematic sampling.Physical examination,Blood samples and morning urine samples were collected in in winter and summer(Summer:June 13 to July 2,2011;Winter:November 30 to December 12,2011),and collect social demographic information and exposure information by questionnaires at the same time.PAH metabolites,creatinine and 8-OHdG in urine were respectively determined by Gas Chromatography-Mass Spectrometer(GC-MS),spectrophotometry and an ELISA kit.The PAH metabolites and 8-OHdG were corrected by urinary creatinine.Cytokines and blood lipids in serum were respectively determined by Bio-Plex Suspension Array System and automatic biochemical analyzer.Two independent sample t-tests(normal data)and non-parametric tests(non-normal data)were used to compare the differences of urinary PAH metabolites,urinary 8-OHdG,cytokines,and blood lipids in winter and summer.Spearman rank correlation analysis was used to explore the associations between PAH metabolites,8-OHdG,cytokines,and lipid profiles.Generalized linear mixed model(GLMM)was used to assess the effect of urinary PAH metabolites on8-OHdG,cytokines and lipid profiles.Then mediation analysis was used to explore oxidative stress and inflammatory mediators in the mediating process of PAH metabolites affecting blood lipids.Results:1.A total of 112 elderly people over the age of 60 were included in this study,including 48 males and 64 females.The average age was 67.54 years old(SD=5.98)and the average BMI was 24.99 kg/m~2(SD=3.23)..The subjects’smoking and drinking status was mainly non-smoking(67%)and non-drinking(79%).There was no statistically significant difference in age and BMI between different genders,and there was a statistically significant difference in smoking and drinking between different genders(P<0.01).2.The median concentrations of single PAH metabolites in the urine of the study population was 1-10μmol/mol Cr,and the median concentrations of the same type of PAHs(∑OHNap,∑OHFlu,and∑OHPhe)was 10-20μmol/mol Cr.The concentrations of PAH metabolites in winter was higher than those in summer.the median concentration of 8-OHdG in urine was higher than that in winter,but there was no significant difference between winter and summer.17 kinds of cytokines median concentrations were several to several hundred pg/mL.IL-1β,IL-4,IL-5 IL-6,IL-7,IL-10,IL-12,IL-13,IL-17,G-CSF,GM-CSF,IFN-γ,MCP-1 and TNF-αwere showed higher concentrations in winter than in summer,while IL-2 and MIP-1βshowed higher concentrations in summer than in winter.Except TNF-α,the concentrations of other cytokines in summer and winter were statistically significant(P<0.05).The concentrations of TC,TG,HDL and LDL were about 1-5 mmol/L,and the concentrations of Apo A1 and Apo B were about 1 g/L.Except for Apo A1/Apo B,the average concentration of others showed that the concentration was higher in winter than in summer.The differences of TC,LDL,Apo A1 and Apo B between winter and summer were statistically significant(P<0.05).3.All urinary PAH metabolites showed statistically significant correlations with the remaining PAH metabolites(P<0.05),and the correlation between isomers of similar substances was higher.There was a positive correlation between PAH metabolites and8-OHdG in urine.There are statistically significant correlations between PAH metabolites and cytokines except for 9-OHFlu and 6-OHChr.There were positive correlations between TC and 2-OHFlu,3-OHFlu,3-OHPhe and∑OHPhe.There was a positive correlation between HDL and∑OHNap.LDL was positively correlated with 2-OHFlu,3-OHFlu,2-OHPhe,3-OHPhe,and∑OHPhe(P<0.05).Other blood lipids were found no statistically significant with PAHs metabolites.Urinary 8-OHdG showed negative correlation with cytokines,and only between MCP-1 and 8-OHdG was statistical significant(P<0.05).Urinary 8-OHdG showed negative correlation with blood lipids except Apo A1/Apo B.Apo B was negatively correlated with8-OHdG(r=-0.250),while Apo A1/Apo B was positively correlated with 8-OHdG(r=0.203).Cytokines were mainly positive correlated with blood lipids,and TC、TG、LDL、Apo A1and Apo B were statistical significant.4.Generalized linear mixed model regression analysis found that after sex,age,BMI,smoking,and seasonal adjustment,most of the PAH metabolites still had a positive effect on 8-OHdG,except for 1-OHNap,9-OHPhe,and 2-OHBcPhe.Most of the PAH metabolites had effects on cytokines,except for 3-OHPhe,9-OHPhe,and 6-OHChr;Metabolites of phenanthrene mainly had influence on blood lipids.Urinary 8-OHdG had significant effects on blood lipids.IL-1β、IL-10、IL-12、G-CSF、GM-CSF and IFN-γhad significant effects on blood lipids.5.Mediating analysis was conducted of the blood lipids as a dependent variable,PAH metabolites was an independent variable,8-OHdG and cytokines were mediate process.After sex,age,BMI,smoking,and seasonal adjustment,PAH metabolites had only direct effect on blood lipids,8-OHdG and cytokines did not have mediating effect.Conclusion:1.Increment of urinary PAH metabolites can cause increases in markers of oxidative stress and changes in markers of inflammatory mediators.8-OHdG IL-1β,IL-2,IL-4,IL-5,IL-6,IL-7,IL-8,IL-12,IL-13,IL-17,G-CSF,GM-CSF,IFN-γ,and MCP-1 were considered of sensitive markers to exposure of PAHs.2.Increment of PAH metabolites in the urine can cause changes in blood lipids,but PAH metabolites have only direct effect on blood lipids and do not work through oxidative stress and inflammatory mediators.