Proteomic analysis of urinary protein markers for accurate prediction of diabetic kidney disorder.
OBJECTIVE
Microalbuminuria is currently the only diagnostic tool available for early diagnosis of diabetic nephropathy. The test is based on immunological detection of small quantities of albumin in the urinary samples of diabetes patients. There are several limitations of the use of microalbuminuria as an index of renal function. It is therefore desirable to identify additional protein markers that would augment prediction of diabetic nephropathy. The aim of this study is to identify urinary protein markers for specific and more accurate prediction of nephropathy in diabetes patients.


METHODS
100 registered Type II diabetic patients were studied. Abundant proteins of microalbuminuria positive urinary samples of these patients were analyzed by proteomics approaches of 2-Dimentional Gel Electrophoresis (2DGE) and mass spectrometry.


RESULTS
2-DGE analysis of the urine sample revealed four main proteins along with albumin in these samples. These were zinc alpha-2 glycoprotein, alpha-1 acid glycoprotein, alpha-1 microglobulin and IgG as identified by Matrix Assisted Laser Desorption Ionization-Tune of Flight (MALDI-ToF) and by western blot. Twenty control samples and three cases with microalbuminuria negative to positive transition does suggest the early and co-appearance of the markers with albumin. We have also analyzed full length spectrum of these samples by MALDI-ToF.


CONCLUSIONS
Our study shows the presence of additional proteins in urine samples of microalbuminuria positive diabetes patients. These proteins can be used as markers for specific and accurate clinical analysis of Diabetic nephropathy. We propose a mass spectrometry based high throughput diagnostic approach to detect these markers in the urine sample.
Jain
Samta
S
Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India.
Rajput
Anuradha
A
Kumar
Y
Y
Uppuluri
N
N
Arvind
A S
AS
Tatu
U
U
D054392:Adipokines; D000328:Adult; D000510:Alpha-Globulins / Q000235:genetics / Q000652:urine*; D015415:Biomarkers / Q000652:urine; D002352:Carrier Proteins / Q000235:genetics / Q000652:urine*; D003928:Diabetic Nephropathies / Q000175:diagnosis / Q000652:urine*; D006023:Glycoproteins / Q000235:genetics / Q000652:urine*; D006801:Humans; D008875:Middle Aged; D009961:Orosomucoid / Q000235:genetics / Q000652:urine*; D011507:Proteinuria / Q000175:diagnosis / Q000652:urine*; D000090203:Zn-Alpha-2-Glycoprotein
D054392:Adipokines; D000510:Alpha-Globulins; D015415:Biomarkers; D002352:Carrier Proteins; D006023:Glycoproteins; D009961:Orosomucoid; C488891:AZGP1 protein, human; D000090203:Zn-Alpha-2-Glycoprotein; C016001:alpha-1-microglobulin