Background Vitamin-D-binding protein (VDBP) is a low molecular weight protein
that is filtered through the glomerulus as a 25-(OH) vitamin D 3/VDBP complex.
In the normal kidney VDBP is reabsorbed and catabolized by proximal tubule
epithelial cells reducing the urinary excretion to trace amounts. Acute
tubular injury is expected to result in urinary VDBP loss. The purpose of our
study was to explore the potential role of urinary VDBP as a biomarker of an
acute renal damage. Method We included 314 patients with diabetes mellitus or
mild renal impairment undergoing coronary angiography and collected blood and
urine before and 24 hours after the CM application. Patients were followed for
90 days for the composite endpoint major adverse renal events (MARE: need for
dialysis, doubling of serum creatinine after 90 days, unplanned emergency
rehospitalization or death). Results Increased urine VDBP concentration 24
hours after contrast media exposure was predictive for dialysis need (no
dialysis: 113.06 ± 299.61ng/ml, n = 303; need for dialysis: 613.07 ± 700.45
ng/ml, n = 11, Mean ± SD, p<0.001), death (no death during follow-up: 121.41 ±
324.45 ng/ml, n = 306; death during follow-up: 522.01 ± 521.86 ng/ml, n = 8;
Mean ± SD, p<0.003) and MARE (no MARE: 112.08 ± 302.00ng/ml, n = 298; MARE:
506.16 ± 624.61 ng/ml, n = 16, Mean ± SD, p<0.001) during the follow-up of 90
days after contrast media exposure. Correction of urine VDBP concentrations
for creatinine excretion confirmed its predictive value and was consistent
with increased levels of urinary Kidney Injury Molecule-1 (KIM-1) and baseline
plasma creatinine in patients with above mentioned complications. The impact
of urinary VDBP and KIM-1 on MARE was independent of known CIN risk factors
such as anemia, preexisting renal failure, preexisting heart failure, and
diabetes. Conclusions Urinary VDBP is a promising novel biomarker of major
contrast induced nephropathy-associated events 90 days after contrast media
exposure