Vitamin D-Binding Protein Is a Potential Urinary Biomarker of Irbesartan Treatment Response in Patients with IgA Nephropathy.
OBJECTIVE
The purpose of this study was to identify predictive markers of irbesartan (an angiotensin receptor blocker) treatment response in immunoglobulin A nephropathy (IgAN) patients.


METHODS
Urine samples were collected both before and after irbesartan treatment in IgAN patients and compared with urine from healthy volunteers. The total urinary protein produced in 24 h was measured to determine therapeutic response. The urinary proteome was evaluated by two-dimensional gel electrophoresis coupled with MALDI-TOF-MS/MS analysis. Western blotting was used to verify protein expression. A receiver operating characteristic curve was used to evaluate the sensitivity and specificity of candidate biomarkers.


RESULTS
Four differentially expressed proteins were identified as vitamin D-binding proteins (VDPs). Western blot showed that urinary VDPs were significantly elevated in nonresponsive versus responsive IgAN patients. The sensitivity, specificity, and accuracy of urinary VDP as a predictive biomarker of irbesartan nonresponsiveness in IgAN were 65%, 85%, and 75%, respectively.


CONCLUSIONS
Our results revealed that urinary VDP might be a useful biomarker for predicting irbesartan treatment response.
1 Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University , Guangzhou, People's Republic of China .|2 Key Laboratory of Nephrology, Ministry of Health , Guangzhou, People's Republic of China .
Jiashun
J
Zeng
1 Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University , Guangzhou, People's Republic of China .|2 Key Laboratory of Nephrology, Ministry of Health , Guangzhou, People's Republic of China .
Qiong
Q
Wen
1 Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University , Guangzhou, People's Republic of China .|2 Key Laboratory of Nephrology, Ministry of Health , Guangzhou, People's Republic of China .
Rong
R
Rong
1 Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University , Guangzhou, People's Republic of China .|2 Key Laboratory of Nephrology, Ministry of Health , Guangzhou, People's Republic of China .
Fengxian
F
Huang
1 Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University , Guangzhou, People's Republic of China .|2 Key Laboratory of Nephrology, Ministry of Health , Guangzhou, People's Republic of China .
Qiongqiong
Q
Yang
1 Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University , Guangzhou, People's Republic of China .|2 Key Laboratory of Nephrology, Ministry of Health , Guangzhou, People's Republic of China .
Xueqing
X
Tang
1 Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University , Guangzhou, People's Republic of China .|2 Key Laboratory of Nephrology, Ministry of Health , Guangzhou, People's Republic of China .
Feng
F
He
1 Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University , Guangzhou, People's Republic of China .|2 Key Laboratory of Nephrology, Ministry of Health , Guangzhou, People's Republic of China .
Naya
N
Huang
1 Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University , Guangzhou, People's Republic of China .|2 Key Laboratory of Nephrology, Ministry of Health , Guangzhou, People's Republic of China .
Xueqing
X
Yu
D000328:Adult; D015415:Biomarkers / Q000652:urine; D001713:Biphenyl Compounds / Q000627:therapeutic use* / Q000652:urine; D015153:Blotting, Western; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D005922:Glomerulonephritis, IGA / Q000188:drug therapy* / Q000652:urine*; D006801:Humans; D000077405:Irbesartan; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry; D013777:Tetrazoles / Q000627:therapeutic use* / Q000652:urine; D016896:Treatment Outcome; D014809:Vitamin D-Binding Protein / Q000378:metabolism / Q000652:urine*
D015415:Biomarkers; D001713:Biphenyl Compounds; D013777:Tetrazoles; D014809:Vitamin D-Binding Protein; D000077405:Irbesartan