| Objective: Gastroesophageal reflux disease (GERD) includes series ofcomplicated upper gastrointestinal diseases which have close relationshipbetween them, while GERD is the important cause to esophagealadenocarcinoma (EA). But there is no certain theory of occurrence-development mechanism and correlations between gastroesophageal refluxrelated diseases. Pro-inflammatory factor IL-8, a member of the CXCchemokine superfamily, plays a significant role in the development ofgastroesophageal reflux related diseases. Analyzing the correlations anddifferences between these diseases by detecting IL-8-251A/T SNP andrelevant expression levels will help to treating and studying gastroesophagealreflux related diseases.The aim of our study was to investigate whether the-251A/Tpolymorphism and expression levels of the IL-8promoter was associated withsusceptibility to GERD and EA. Furthermore, the occurrence-developmentmechanism and correlations between gastroesophageal reflux related diseases.Methods: This population-based case-control study included102casesnon-erosive reflux disease (NERD),105cases reflux esophagitis (RE),200cases Barrett`s esophagus (BE),181cases reflux esophagitis&Barrett`sesophagus (RB),56cases esophageal adenocarcinoma (EA) and121caseshealthy controls. The total patients were diagnosed by gastroscope andhistopathology, detected the infection of H.pylori by RUT and histopathology.In the same period, we questioned patients with reflux diagnosticquestionnaire (RDQ) and collected the disease history, personal history, and soon. Genomic DNA was extracted using a commercially available kit. IL-8polymorphisms were analyzed by polymerase chain reaction (PCR)-restrictionfragment length polymorphism (RFLP). Random sampling of DNA sequencing analysis was used to confirm the results of IL-8genotyping. Totalprotein amount of the esophageal lesion areas was measured using a BCAmethod and the IL-8level was assayed in duplicate using an enzyme-linkedimmunosorbent assay kit (invitrogen; California, America). The IL-8levelswere expressed as picograms of cytokine per milligram of protein (pg/mgprotein). Statistical analysis of data used SPSS13.0Package (SPSS Company,Chicago, Illinois, USA), P<0.05considered statistically significant, Hardy-Weinberg analysis was performed by comparing the observed and expectedgenotype frequencies in study groups using Chi-square test. Comparison of theIL-8genotype and allelotype distribution in the study groups was performedby means of two-sided contingency tables using Chi-square test. The oddsratio (OR) and95%confidence interval (CI) were calculated using anunconditional logistic regression model and adjusted by sex, age, H.pyloriinfection, smoking and drinking status accordingly.Results:1The mean scores of RDQ of RE was about14.4±9.0,55.2%was above12, the distribution was higher than that of BE (9.9±6.9,32.0%of≥12)(P=0.000). Scores of RB and EA were15.3±7.3and13.8±7.0.73.5%and55.4%of≥12, the distribution of RE, RB and EA has no obviousdifference (P>0.05).2Demographic characteristics of study objects2.1The constituent ratio of sex and age in RE, RB and EA has significantdifference(P values were0.026,0.001,0.028;0.021,0.018,0.019respectively).After adjusted, male could only increase the risk of developing RB (OR=1.818,95%CI=1.079-3.064), and advanced age would rise the risk of these threegroups (OR=2.303,95%CI=1.268-4.181; OR=1.770,95%CI=1.064-2.944;OR=2.278,95%CI=1.087-4.774).2.2H.pylori infection rate (43.1%,29.5%,30.5%,28.7%,23.2%) of everydisease group has no statistic difference compared with controls (38.0%), theOR of RB was0.464(95%CI=0.221-0.974) adjusted by sex, age, smoking anddrinking status. 2.3Compared with controls (19.0%), the proportion of smokers of NERD, BEand EA (23.5%,18.5%,30.4%) has no statistic difference, that of RE and RB(31.4%å'Œ29.3%) has obvious difference (P=0.031,0.044). But when adjustedby sex, age, H.pylori infection and drinking status, the difference disappeared(OR=1.733,1.556, P>0.05).2.4The proportion of drinkers of RE (21.9%) was higher than that of controls(8.3%)(P=0.004), OR adjusted by sex, age, H.pylori infection and smokingstatus was2.910(95%CI=1.207-7.012).3The detection result of IL-8-251A/T polymorphisms3.1The distribution of the IL-8polymorphisms among NERD, RE, BE, RBand EA patients and healthy controls did not significantly deviate from thoseexpected by Hardy-Weinberg equilibrium (P>0.05). The frequencies of theIL-8-251T/T, A/T, A/A and A carriers in healthy controls were45.5%,42.1%,12.4%and54.5%.30.9%,46.4%,22.7%and69.1%in RB, the frequencies ofA/A and A carriers were higher than that in controls (χ2=5.049,6.573;P=0.025,0.010) while there were no significant difference between NERD,RE, BE, EA and controls. But compared with T/T genotype, adjusted by sex,age, H.pylori infection, smoking and drinking status, carrying A allelotypecould be the risk factor of developing RB and EA (OR=1.722,95%CI=1.011-2.932; OR=2.378,95%CI=1.134-4.986), so could A/Agenotype (OR=2.454,95%CI=1.168-5.155; OR=3.063,95%CI=1.060-8.853),in addition, A/T also increased the risk of EA (OR=2.197,95%CI=1.008-4.791).3.2The frequencies of the IL-8-251T/T, A/T, A/A and A carriers of CFM,GCM and SIM in RB were42.9%,32.1%,25.0%,57.1%;33.3%,44.4%,22.3%,66.7%;26.9%,50.9%,22.2%,73.1%. Compared with T/T genotype,the frequencies of A/A and A carriers of SIM had statistic difference (χ2=3.899,8.503; P=0.048,0.004). After adjusted, carrying A/A genotype as wellas A allelotype could increase the risk of developing SIM in BE and RB(OR=2.555,95%CI=1.007-6.484; OR=2.109,95%CI=1.086-4.096; OR=2.966,95%CI=1.246-7.061; OR=2.195,95%CI=1.151-4.184). 4The assay result of IL-8levels4.1The mean relative IL-8levels of NERD and BE were61.6±45.1and77.6±65.8, compared with controls (63.4±59.5) and NERD, the difference of BEwas significant (P=0.007,0.045). Those of RE and RB were406.9±640.3and432.3±526.6, level of EA rose obviously which reached820.4±806.6.4.2The mean relative IL-8levels corresponding to A allelotype of RB(469.4±525.9) was higher than to T/T genotype (342.4±522.8) that hadsignificant difference (P=0.011).4.3In RB group, the mean relative IL-8levels corresponding to genotypes ofSIM [365.4±668.4(T/T),487.1±576.8(A/T),576.6±689.4(T/T)] were different(P=0.044). The mean relative IL-8level corresponding to A carriers(516.5±612.7) was higher than that corresponding to T/T genotype (P=0.013)too.Conclusions:1Male significantly enhanced susceptibilities to the risk of developing RB.2Advanced age (≥55) enhanced susceptibilities to RE, RB and EA.3H.pylori infection obviously reduced susceptibilities to EA.4Drinking was a risk factor of developing RE.5Compared with T/T genotype, carrying IL-8-251A/A genotype and Aallelotype could significantly increase the risk of developing SIM in BE andRB.6Compared with T/T genotype, carrying IL-8-251A/T, A/A genotype and Aallelotype could significantly increase the risk of developing EA.7The mean relative IL-8levels of RE, RB and EA were significantly higherthan that of controls, especially in EA.8The mean relative IL-8level corresponding to A allelotype of SIM in RBwas significantly higher than corresponding to T/T genotype.9There might exist a progressive relationship of severity between RE, RBand EA, NERD should has its own evolution processes which was differentfrom RE. The relation between BE and EA was not as strong as RB and EA,thus RB could be considered as the dangerous group to esophageal adenocarcinoma. |
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