Study On Relationship Between Nitric Oxide(NO), Endothelin(ET-1) And Intradialytic Dynamic Changes

Objective: The etiology of hemodialysis (HD)-induced hypotension and hypertension remains speculative. There is mounting evidence that nitric oxide (NO) and endothelin (ET-1) may play a vital role in these hemodynamic changes. We examined intradialytic dynamic changes in NO and ET-1 levels and their role in the pathogenesis of hypotension and rebound hypertension during HD.Methods: Twenty four (24) end-stage renal disease (ESRD) patients on HD in the blood purification center of the Second Hospital of Hebei Medical university were selected from October in 2010 to February in 2011,including 14 male and 10 femal. All the patients have been treated with maintenance hemodialysis for more than three months, the value of Kt / V is 1.2 to 1.4. The MHD patients were grouped according to their hemodynamic profile: those with stable blood pressure throughout the HD (Group I), those who had hypotension syndrome and had decrease in systolic pressure 20mmHg from baseline or <90mmHg during HD ,or not along with syndrome, but incidence of decrease in systolic pressure >50% during HD (Group II), and those who were normotensive or hypertensive at initiation of dialysis, but experienced elevation in MAP of 15 mmHg intradialysis (Group III). Patients with pulmonary diseases, and ongoing infection or inflammatory diseases were excluded from the study. Also, patients with poor left ventricular function and ischemic heart disease requiring nitrates for coronary vasodilatation or angiotensin converting enzyme inhibitor were not recruited. In addition, 8 healthy persons were included as a control group. Pulse and blood pressure were monitored before, during (every hour), and after HD session. NO and ET-1 levels were measured at the beginning, middle, and end of HD. 8 health persons, fasting elbow venous blood sample were selected. NO was determined by nitrate reductase, ET-1 was determined by radioimmunoassay.These data were processed by SPSS 17.0 . Metric data was expressed as average±standard deviation, to check up the data of all groups with normal test and anova test. The compare between groups with one-way ANOVA. The compare between before and after oneself with Paired-sample t test. P<0.05 was significantly different.Results:1 Age, gender,dry weight,levels of ALB,ultrafiltration and HD years were comparable in the three MHD groups; and age,weight were comparable with control group;2 NO levels profile2.1 Pre-dialysis NO levels were significantly higher in MHD patients compared to the controls(P<0.05), but were comparable in the three study groups(P>0.05).2.2 During HD, NO levels were progressive decrease in three groups, GⅠ(55.21±17.74 VS 137.51±42.91μmol/L),GⅡ(61.89±17.17 VS 162.18±42.68μmol/L),GⅢ(58.25±9.40 VS154.64±48.10μmol/L)(P<0.05)。2.3 Post-dialysis NO were comparable in the three HD groups.3 ET-1 levels profile3.1 Pre-dialysis ET-1 levels were significantly higher in MHD patients compared to the controls(P<0.05), but were comparable in the three study groups(P>0.05).3.2 ET-1 levels change during HD There was insignificant change in ET-1 levels during HD in group I (125.43±37.74, 141.36±42.58 VS 143.29±40.34pg/ml,P>0.05),insignificant progressive decrease in group II(148.70±16.62,140.10±41.63 VS 154.95±32.14pg/ml,P>0.05), significant increase in group III, mid-HD ET-1 was higer compared to pre-dialysis and post-dialysis(121.22±43.18,171.92±21.87 VS 167.43±45.68pg/ml).3.3 Post-dialysis ET-1 were comparable in the three HD groups.4 NO /ET-1 profileDuring HD, NO /ET-1 were progressive decrease in three groups, post-dialysis were significantly lower than pre-dialysis. But post-dialysis NO /ET-1 was insignificant change compared to mid-dialysis in group II. The descent rate of mid-dialysis NO /ET-1 were significantly higher in group III compared to group I and group II.Conclusions:1 The patients on hemodialysis exist endothelial dysfunction.2 Changes of ET-1 levels and NO /ET-1 during HD may paly a role in the pathogenesis of intradialytic hypertension.3 The mechanism of intradialitic hepotension is complex, changes of NO levels and NO /ET-1 may paly a role in the course.