| Objective With the development of blood purification technology, thesurvival rates of hemodialysis patients have been significantly improvedcompared with the past. However, cardiovascular disease (CVD) remains themajor complications and mortality of maintenance dialysis patients(MHD).It has been shown by a large number of studies that high fluxhemodiafiltration (HDF) can improve lipid metabolism, reduceinflammation, and decrease the morbidity and the mortality of thecardiovascular diseases for the maintenance dialysis patients. But, themechanism that HDF can mitigate lipid metabolism and reducecardiovascular events in patients remains unclear. ATP-binding cassettereceptor A1（ABCA1） and ATP-binding t cassette receptor G1(ABCG1)are the most important receptors in cholesterol reverse transport（RCT）andplays important roles in both lipid metabolism and atherosclerosisdevelopment. Our objective is to examine the effects and mechanism ofdifferent dialysis on the formation of foam cells and the expression of ABCA1and ABCG1in Uremia patient’s peripheral blood mononuclearmacrophages. To observe different dialysis uremic patient’s peripheralblood Treg/Th17proportional change and the relationship betweenTreg/Th17proportional change and the expression of ABCA1and ABCG1.The study may provide a new theoretical foundation for Uremic patientswith atherosclerosis，as well as offer a new pathway for clinical preventionand treatment of atherosclerosis in uremic patients.Methods We investigated30uremia patients treated by HD,30patientstreated by HDF and20healthy volunteers. ALL patients were receivedtreatment in the department of kidney, first hospital affiliated to Chongqingmedical university. Peripheral blood mononuclear cells (PBMCs) wereisolated from venous blood before dialysis and stimulated to make themtransfer to macrophages by Macrophage colony-stimulating factor.Macrophages were identified by Oil red O dyeing and byimmunofluorescence staining of cd68. The cellular contents of totalcholesterols，Cholesterol Ester and Free Cholesterol in different groups weredetected by enzymatic colorimetry. The expression of ABCA1and ABCG1mRNA was detected by real-time fluorescent quantitative PCR, and theexpression of ABCA1and ABCG1protein was detected by Western-blot.Mononuclear cells were isolated from peripheral blood by density gradientcentrifugation，Treg and Th17cells proportion and Treg/Th17proportionwas measured by flow cytometry. The effects of Treg/Th17imbalance on the expression of ABCA1, ABCA1were investigated and to clarify therelationship between the two factors.Results1． Compaired with control group, total cholesterol andCholesterol ester in both HD and HDF groups increased significantly（P<0.01）. Compaired with control group, free cholesterol in both HD andHDF groups increased significantly（P<0.01）, total cholesterol and Chol-esterol ester in HDF group decreased （P<0.05）.2．Real-time fluorescent quantitative PCR results are as follows:compared with controls, the expression of ABCA1mRNA and ABCG1mRNA in both HD and HDF group were significantly lower (P<0.01,P<0.01); compared with HD group, the expression of ABCA1mRNA andABCG1mRNA in the HDF group increased significantly (P<0.01, P<0.05).3. Compared with controls, the expression of ABCA1and ABCG1protein in both HD and HDF group was significantly lower (P<0.01,P<0.05); compared with HD group, the expression of ABCA1and ABCG1protein in the HDF group increased significantly (P<0.05, P<0.05).4. The percent of Treg cell in peripheral blood（CD4+CD25+Foxp3+/CD4+T cells，％) in HD and HDF group patients was remarkably higherthan that in healthy controls (P<0.05)，The percent in HDF group patientswas higher than that in HD group(P<0.05)。The percent of Th17cell inperipheral blood（CD4+IL17+／CD4+T cells，％) in HD and HDF grouppatients was and remarkably higher than that in healthy controls (P<0.05)， The percent in HDF group patients was higher than that in HD group(P<0.05)。The ratio of Treg/Thl7in HDF group was obviously lower thancontrol group (P<0.05), the ratio in HDF group increased significantlycompaired with HD group (P<0.05).5. Compared with controls, the expression of Foxp3mRNA in both HDand HDF group were significantly lower (P<0.01, P<0.01)；Compaired withHD group, the expression of Foxp3mRNA in the HDF group increasedsignificantly (P<0.05). Compared with controls, the expression of ROR-γtmRNA in both HD and HDF group were significantly higher (P<0.01,P<0.01)；Compaired with HD group, the expression of ROR-γt mRNA in theHDF group decreased significantly (P<0.05).6. The level of IL-6TNF-αin HDF and HD groups were significantlyhigher than those in control group（P<0.05）, The level of IL-10in HDF andHD groups were lower than this in control group（P<0.05）. The level of IL-6TNF-αin HDF groups was significantly higher than those in HD group（P<0.05）, The level of IL-10in HDF groups was lower than this in HDgroup（P<0.05）.7. The proportion of Treg cells in patients receiving hemodialysis waspositively correlated with ABCA1, ABCG1mRNA (r=0.793, P<0.05); r=0.698,P<0.05); And proportion of Th17cell with ABCA1, ABCG1mRNAshowed a negative correlation (r=-0.711, P<0.05and r=-0.387, P<0.05);Proportion of Treg cells in patients receiving hemodialysis with ABCA1, ABCG1protein was positively correlation (r=0.791, P<0.05, r=0.761,P<0.05); The proportion of Th17cell, ABCA1and ABCG1protein showeda negative correlation (r=-0.577, P<0.05and r=0.-685, P<0.05).Conclusion Macrophage cholesterol efflux receptors ABCA1, ABCG1of maintenance dialysis patients were down-regulated， high-fluxhemodiafiltration can improve the expression of ABCA1and ABCG1.Dysfunction of ABCA1and ABCG1associated with unbalanced proportionof Treg/Th17cells and Microinflammatory. Compared with HD，HDF canimprove dialysis patients Treg/Th17cell ratio, reduced the release ofproinflam-matory cytokines, increase the release of the suppression ofinflammatory cytokines, increased expression of ABCA1and ABCG1,thereby reducing the incidence of atherosclerosis and cardiovascularcomplications. |
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