| Objective: This study was performed to investigate the relationshipbetween the polymorphisms of DDAH-2and the serum ADMA level in MHDpatients. In order to provid a rationale for the study of high incidence ofcardiovascular disease in MHD patients. In our study we want to discussthe effect of DDAH-2(-449G/C) single nucleotide polymorphism on theserum ADMA concentration.Methods: We selected a total of126MHD patients as subjects in theBlood Purification Center of4th Hospital of Hebei Medical University, andrecorded their clinical and laboratory examination data. Inclusion criteria:①Accepting hemodialysis therapy more than six months;②TakingHemodialysis2~4times a week,4~4.5hours each time;③Without acuteinfection,trauma and other active disease in the past month;④Without takingreduce blood cholesterol drugs and antioxidants in past two weeks;⑤Withoutchanging in usage and dosage of erythropoietin in past three months;⑥Volunteer in our study. Exclusion criteria:①Having serious hepatic functionlesion;②Active stage of autoimmune disease;③Having serious malnutrition.In our research, the protopathy of subjects were as follows,45patients ofchronic glomerulonephritis,22patients of diabetic nephropathy,13patients ofhypertensive nephropathy,10patients of ADPKD,5patients of aristolochicacid nephropathy,3patients of chronic pyelonephritis,3patients ofobstructive nephropathy,7patients of others, and18patients of unknowncauses. The ultrapure water and the bicarbonate dialysate were always usedduring our research, temperature ranges from36℃to36.5℃.The contents ofDialysate include Na+of140mmol/L,K+of2.0~3.0mmol/L and Ca2+of1.25～1.5mmol/L.The flow rate of dialysate is500mL/min and the flow rate ofblood ranges from200to300mL/min. FX·80dialyser was used during hemodialysis.Fasting blood sample was collected from each subjects.wecollected2ml venous blood to abstract DNA,the abstracted DNA was saved at-80℃;Before hemodialysis we collected2ml venous blood which was saved at-80℃to determine the serum ADMA level. DNA was obtained from bloodsamples using TIANamp Blood DNA Kit. The polymorphisms of DDAH-2(-449G/C) was detected by Snapshot gene sequencing. The serum ADMAlevel was determined by high performance liquid chromatography-massspectrometry (HPLC-MS).Statistical analysis was accomplished by spss13.0statisticals Software. Measurement data given as means±SD.Inter-groupdifference was tested by independent t-test or analysis of variance. Singlelinear correlation was applied to assess the influencing factors of the serumADMA level, followed by a multiple linear regression analysis, P<0.05wasconsidered statistically significant.Results:1The subjects were divided into two groups by gender,which were malegroup and female group.There were62patients in male group;64patients infemale group.The serum ADMA concentration of male group was175.44±60.08ng/ml,female group was186.99±61.77ng/ml. There was nostatistical significance between them (P＞0.05).2The subjects were divided into three groups by smoking history,which weresmoking group,stop smoking group and non-smoking group.There were18patients in smoking group,33patients in stop smoking group,75patients innon-smoking group. The serum ADMA level of smoking group was158.87±65.30ng/ml,stop smoking group was185.74±63.69ng/ml,non-smokinggroup was184.74±58.34ng/ml.There was no statistical significance betweenthem (P＞0.05).3The subjects were divided into two groups by diabetes mellitus history,diabetic group and non-diabetic group.There were26patients in diabeticgroup and100patients in non-diabetic group. The serum ADMAconcentration of diabetic group was178.15±62.37ng/ml, non-diabetic groupwas193.46±54.72ng/ml,There was no statistical significance between them (P＞0.05).4The subjects were divided into two groups by blood pressure level.SBP≥140mmHg or DBP≥90mmHg was standardization. hypertension group andnormotensive group.There were87patients in hypertension group and39patients in normotensive group group. The serum level of ADMA inhypertension group was195.69±60.92ng/ml, normotensive group was149.22±47.98ng/ml.There was statistical significance between them (P<0.05).5We selected single linear correlation to search the influencing factors ofADMA.We found that there was no correlation between body mass index(BMI), Predialysis diastolic pressure, HGB, CRP level,the serum leves oftriglyceride(TG), low density lipoprotein(LDL), high densitylipoproteins(HDL) and the serum ADMA concentration.Then,we found thatthere was a direct correlation between age and the serum ADMA level,Spearman correlation coefficient r=0.191,P=0.033;Dialysis age and the serumADMA level was positive correlated with Spearman correlation coefficientr=0.296,P=0.01;Predialysis systolic pressure and the serum ADMA level waspositive correlated with Spearman correlation coefficient r=0.564, P<0.001;the serum level of total cholesterol(CHOL) and the serum ADMA level waspositive correlated with Spearman correlation coefficient r=0.396, P<0.001.6The genotype distribution of DDAH-2(-449G/C) was consistent with thelaw of Hardy–Weinberg equilibrium (χ2=2.22,P=0.136). DDAH-2(-449G/C)Genotype distribution was as follows, GG32(25%),CG71(57%),CC23(18%); G allele frequency was53.6%, C allele frequency was46.4%;Whenthe DDAH-2(-449G/C)was GG, CG, CCgenotypes,the serumADMAconcentration was168.43±52.39ng/ml,185.78±61.94ng/ml,185.42±68.77ng/ml.There was no statistical significance between them P＞0.05.7According to analytic result we acquired above,we established multiplelinear regression equation. The regression equation was Y=-92.614+0.355Xdialysis age+1.437XPredialysis systolic pressure+12.371Xtotal cholesterol(multiple correlationcoefficient R=0.596,P <0.05).The results show that, the serum ADMA leveland dialysis age,predialysis systolic pressure,the serum total cholesterol level were the linear regression relationship.Conclusion:1In MHD patients, gender, Smoking history, BMI, diabetes mellitus history,HGB, serum levels of triglyceride, low density lipoprotein, high densitylipoproteins are not influencing factors of the serum ADMA level.2The single nucleotide polymorphism of DDAH-2(-449G/C) has no effecton the serum ADMA concentration in MHD patients.3In MHD patients, dialysis age,Predialysis systolic pressure and the serumtotal cholesterol level are independent risk factors for the serum ADMAconcentration. |
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