Multicentric validation of proteomic biomarkers in urine specific for diabetic nephropathy.
BACKGROUND
Urine proteome analysis is rapidly emerging as a tool for diagnosis and prognosis in disease states. For diagnosis of diabetic nephropathy (DN), urinary proteome analysis was successfully applied in a pilot study. The validity of the previously established proteomic biomarkers with respect to the diagnostic and prognostic potential was assessed on a separate set of patients recruited at three different European centers. In this case-control study of 148 Caucasian patients with diabetes mellitus type 2 and duration ≥5 years, cases of DN were defined as albuminuria >300 mg/d and diabetic retinopathy (n = 66). Controls were matched for gender and diabetes duration (n = 82).


RESULTS
Proteome analysis was performed blinded using high-resolution capillary electrophoresis coupled with mass spectrometry (CE-MS). Data were evaluated employing the previously developed model for DN. Upon unblinding, the model for DN showed 93.8% sensitivity and 91.4% specificity, with an AUC of 0.948 (95% CI 0.898-0.978). Of 65 previously identified peptides, 60 were significantly different between cases and controls of this study. In <10% of cases and controls classification by proteome analysis not entirely resulted in the expected clinical outcome. Analysis of patient's subsequent clinical course revealed later progression to DN in some of the false positive classified DN control patients.


CONCLUSIONS
These data provide the first independent confirmation that profiling of the urinary proteome by CE-MS can adequately identify subjects with DN, supporting the generalizability of this approach. The data further establish urinary collagen fragments as biomarkers for diabetes-induced renal damage that may serve as earlier and more specific biomarkers than the currently used urinary albumin.
Alkhalaf
Alaa
A
Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Zürbig
Petra
P
Bakker
Stephan J L
SJ
Bilo
Henk J G
HJ
Cerna
Marie
M
Fischer
Christine
C
Fuchs
Sebastian
S
Janssen
Bart
B
Medek
Karel
K
Mischak
Harald
H
Roob
Johannes M
JM
Rossing
Kasper
K
Rossing
Peter
P
Rychlík
Ivan
I
Sourij
Harald
H
Tiran
Beate
B
Winklhofer-Roob
Brigitte M
BM
Navis
Gerjan J
GJ
D015415:Biomarkers / Q000652:urine*; D016022:Case-Control Studies; D003928:Diabetic Nephropathies / Q000652:urine*; D019075:Electrophoresis, Capillary; D006801:Humans; D057230:Limit of Detection; D013058:Mass Spectrometry; D040901:Proteomics
D015415:Biomarkers