The Role Of Urinary Smad1in Diabetic Nephropathy

Objective:In this study, we investigated the excretive level of urinary Smad1in patientswith type2diabetes and analysed the concentration changes of urinary Smad1inpatients with diabetic nephropathy (DN)to explored whether urinary Smad1can beused as an early diagnostic index and a severity index of diabetic nephropathy. At thesame time, we intended to research the influencing factors for urinary Smad1.Methods:132type2diabetic patients from the first affiliated hospital of Jinan university,Department of Endocrinology and50healthy people from Physical ExaminationCenter were enrolled in the study. Patients were divided into normal albuminuriagroup (NAU), low-grade albuminuria group(LAU), high-grade albuminuriagroup(HAU) and very high-grade albuminuria group (VHAU) according to the levelof albumin-creatinine ratio (ACR),which refered to the NFK and FDA internationalconference for the grading of albuminuria. Among them, LAU、 HAU and VHAUwere treated as DN group and NAU was non-diabetic nephropathy group, whilehealthy crowd was control group. Smad1in the fresh morning urine was examinedusing ELISA and Smad1-creatinine ratio (SCR) was compared at last. The differenceswere then calculated and tested using SPSS16.0.Results：1. The SCR level in type2diabetic patients was higher than healthy crowd withstatistically significant (P <0.05).2. The SCR level was significantly higher in DN group than non-diabeticnephropathy group (P <0.05). The areas under the receiver operatingcharacteristic curve to diagnose DN for SCR was0.716（P=0.000）. WhenSCR≧5.64ug/g, the sensitivity (70.7%) and specific degrees (60.8%) ofdiagnosing DN for SCR were higher.3. There was no statistical significant difference in SCR level between LAU group and NAU group (P>0.05).4. The SCR level in VHAU group was higher compared with HAU group and LAUgroup while HAU group was higher than LAU group with statistically significant(P <0.05).5. Pearson correlation analysis demonstrated ACR, fasting plasma glucose(FPG)and blood urea nitrogen (BUN)were positively correlated with The SCR levelwith statistically significant (r=0.304、0.273、0.147; P=0.000、0.000、0.049respectively). In contrast, The SCR level was not correlated with body mass index,glycated hemoglobin, systolic blood pressure, blood lipid, blood uricacid, liverand kidney function with statistical significant difference (P>0.05).6. Mutiple linear regression analysis demonstrated an independent associationbetween SCR and ACR (P<0.05),FPG (P<0.05). There gression equation wasSCR=0.592+0.0004(ACR)+0.023(FPG).Conclusion:Urinary Smad1may be one of the potential diagnosis and evaluation index ofdiabetic nephropathy. But it can’t predict the early diabetic nephropathy. In addition,ACR and FPG may be independent related factors in influencing urinary Smad1level.