| Objective:Diabetic kidney disease(DKD)is one of the most common microvascular complications of diabetes.DKD is primary basic cause of end-stage renal disease.Urinary microalbumin(UMA)is considered as a clinical manifestation of early DKD.But long-term studies have shown its sensitivity and specificity are poor.Study found that kidney damage may occurred already in some patients during impaired glucose tolerance(IGT).So,in contrast to DKD,we call the kidney injury at this stage as "IGT nephropathy".Although the renal damage in IGT was observed in our previous animal experiments,it needs to be further tested in clinical patients.The biomarkers for early diagnosis of DKD,such as Liver-fatty acid binding protein(L-FABP),kidney injury molecule-1(Kim-1),cystatin(CysC),β2-microglobulin(β2-MG),and so on,but these markers whether also changed in the stage of "IGT nephropathy",also need be vertified in clinical patients.Through proteomics iTRAQ technique,we have screened the protein-Varosin(VASN).VASN is a newly discovered protein in recent years,it is expressed in kidney and involved in the processes of vascular repair,development of tumors and so on.But whether it can as a new biomarker for early diagnosis of "IGT nephropathy" is needed vertify in clinical enlargement of sample,whether it is also involved in the pathogenesis of "IGT nephropathy" also remain to be researched.So,our study observed the changes of renal impairment indicators and VASN in the population divided into 5 groups : normal control(NC),IGT,IGT nephropathy(IGTN),type 2 diabetes(DM)and DKD,From the clinical perspective to vertify the renal damage in IGT patients and the value of VASN in "IGT nephropathy" and DKD,and explored the possible role of VASN in the pathogenesis of "IGT nephropathy".Methord: 1.Kidney function,blood sugar,insulin,UMA,retinol binding protein(RBP),alpha-galactosidase(GAL),N-acetyl-beta-D-glucosaminidase(NAG),transferrin(TF),β2-MG,IgG,TF,L-FABP,Kim-1,CysC and VASN were were detected.2.The kidney tissues in previous experiment of ZDF rats at IGT,DM stages and ZL rats were used to observed the localized expression of VASN in kidney.3.VASN,thioredoin 2(TRX2),reactive oxygen species(ROS),the levels of albumin uptake by Human renal tubular epithelial cell(HK-2)were valued.4.Down-regulation and up-regulation of VASN espression,VASN,TRX2,ROS,the levels of albumin uptake were detected after the induction of hypoxia.Results: 1.The eGFR in IGTN group was higher than that in NC group(P < 0.05).2.Compared with NC group,UMA,CysC,GAL,NAG,NGAL,KIM-1 and L-FABP were all increased in IGTN group(P < 0.05).4.Compared with NC group,VASN was decreased in IGTN group about 27%.5.In IGTN group,the level of urine VASN was negatively correlated with CysC,GAL,NAG,NGAL.ROC curve: the sensitivity and spectificity of IGT nephropathy were 78.6% and 64.7% respectively(P < 0.05).6.VASN mainly distributes in renal tubules,compared with NC group,expression of VASN in IGT phase was decreased about 40%(P < 0.05).7.Under hypoxia condition,expression of VASN was decreased,ROS was increased about 59%,the level of albumin uptake was reduced 50%,siRNA VASN can reduce expression of TRX2,ROS was elevated 1.4 times,the level of albumin uptake was decreased about 73%.Overexpress VASN,the expression of TRX2 was also elevated,ROS was reduced 56%,albumin reabsorption function was recoved about 90%.Conclusion: 1.It was further confirmed that some patiens with IGT stage have kidney injury,which was manifested by different degrees of tubular and glomerular damage.Tubular injury may be the main pathophysiological changes at this stage.2.VASN was expected to be a new marker for early diagnosis of “IGT nephropathy”.3.VASN was mainly expressed in renal tubules.The expression of VASN in kidneys of IGT and DM rats were lower than that of normal rats.4.Under hypoxia condition,the down-regulated VASN increased oxidative stress injury in HK-2 cells thtough down-regulating the expression of TRX2,resulting in reduced reabsorption of albumin. |
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