URINARY PROTEOME ANALYSIS USING CAPILLARY ELECTROPHORESIS COUPLED MASS
SPECTROMETRY FOR THE DETECTION OF DIABETES-ASSOCIATED PATHOLOGIES

Harald Mischak

Mosaiques Diagnostics & Therapeutics AG, Hannover, Germany

Urine is an attractive source for clinical diagnosis due to its ready
availability and noninvasive, straightforward collection. Inspection of
urinary proteins/peptides holds promise for better understanding
vascular and renal (patho-)physiology ^1^.

We have generated a database of human urinary polypeptides, based on
individual high-resolution data from more than 3,500 urine samples from
healthy individuals and patients with assorted diseases. All samples
were analyzed by capillary electrophoresis coupled to mass spectrometry
(CE-MS), resolving approximately 1,500 peptides per sample. The
resulting database currently contains over 100,000 unique urinary
peptides, with more than 5,000 found in at least 20 percent of all
samples, and more than 1,000 sequences to date. This database serves to
construct robust classifier models for diagnosis, stratification, and
monitoring of a wide range of diseases^2-4^.

Several biomarkers can be defined for diabetic complications (e.g.,
coronary artery disease and diabetic nephropathy), which allow high
confidence diagnosis of blinded samples from urinary proteome
analysis^1,2,5-7^. Further, diagnosis at very early stages of disease,
prognosis, and assessment of therapeutic response is possible^5,6,8^. As
single biomarkers generally do not allow high accuracy definition of a
disease, a panel of biomarkers combined with specific models is
utilized; this not only allows one to distinguish healthy from diseased
samples, but also allows for differential diagnosis with high
sensitivity and specificity. Such models enable noninvasive detection of
multiple diseases. Any multiparametric approach is at risk of
overfitting; therefore, the diagnostic models were validated in multiple
clinical studies involving blinded assessment of hundreds of samples.

Current data indicate that CE-MS based urinary proteome analysis enables
detection of early stage disease and may help elucidate pathophysiology
based on identified biomarkers.

Reference List

^1^ D. Fliser*, et al.*, \"Advances in urinary proteome analysis and
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^2^ E. Schiffer, H. Mischak, and J. Novak, \"High resolution
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^3^ S. Decramer*, et al.*, \"Predicting the clinical outcome of
congenital unilateral ureteropelvic junction obstruction in newborn by
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^4^ D. Theodorescu*, et al.*, \"Discovery and validation of new protein
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^5^ H. Mischak*, et al.*, \"Proteomic analysis for the assessment of
diabetic renal damage in humans,\" Clin. Sci. (Lond). **107**(5), 485
(2004).

^6^ L. U. Zimmerli*, et al.*, \"Urinary proteomics biomarkers in
coronary artery disease,\" submitted.

^7^ C. von zur Muhlen*, et al.*, \"Plasma and in particular urine
proteome patterns can identify coronary artery disease,\" submitted.

^8^ K. Rossing*, et al.*, \"Impact of diabetic nephropathy and
angiotensin II receptor blockade on urinary polypeptide patterns,\"
Kidney Int. **68**(1), 193 (2005).