First clinical experience with β-trace protein (prostaglandin D synthase) as a marker for perilymphatic fistula

Beta-trace protein in pediatric otitis media with effusion

OBJECTIVES

The middle ear cleft connects by membranes to the inner ear and the subarachnoid space particularly in infants. In order to gain more insight about the permeability between the two compartments we quantified the concentration of beta-trace protein - a highly specific marker for CSF and perilymph but not for serum and mucosal effusion - in middle ear secretions from children with otitis media with effusion.

METHODS

One-hundred and three patients were included and 93 samples from secretory otitis media were collected during myringotomy or explorative tympanotomy. Thirty-eight patients of 103 had to be excluded (36.9%). Of the 93 collected samples from 65 subjects, 82 viscous samples were pre-diluted 1:1 with tyloxapol. In spite of the attempt to pre-dilute the viscous samples, 30 glue-like samples of 93 were not applicable for nephelometry. The final analysis was made on 63 samples of 52 subjects (median age 3 years) which were quantified for beta-trace protein using immunonephelometry.

RESULTS

In 3/63 samples the beta-trace protein values were below the detection range (<0.2 mg/L) and in 1/63 it was beyond with 18.3mg/L. The median beta-trace protein value for 59 samples within the measuring range was 2.4 mg/L, range 0.2-14.2.

CONCLUSION

In pediatric middle ear effusions, the beta-trace protein concentration was found to have a high range compared to other body fluids from other studies. In other studies, the values for serum (0.59 mg/L) or mucosal secretion (0.003-0.12 mg/L) were lower and the values in CSF (18.4 mg/L) or perilymphatic fluid (23.5 mg/L) were highest. This finding might indicate a weak barrier between the cerebrospinal fluid space or inner ear fluid compartments on the one side and the tympanic cavity on the other side given the condition of otitis media with effusion. The detection of beta-trace protein might be important to assess the risk of impending complications.

Suction blister fluid as potential body fluid for biomarker proteins

Early diagnosis is important for effective disease management. Measurement of biomarkers present at the local level of the skin could be advantageous in facilitating the diagnostic process. The analysis of the proteome of suction blister fluid, representative for the interstitial fluid of the skin, is therefore a desirable first step in the search for potential biomarkers involved in biological pathways of particular diseases. Here, we describe a global analysis of the suction blister fluid proteome as potential body fluid for biomarker proteins. The suction blister fluid proteome was compared with a serum proteome analyzed using identical protocols. By using stringent criteria allowing less than 1% false positive identifications, we were able to detect, using identical experimental conditions and amount of starting material, 401 proteins in suction blister fluid and 240 proteins in serum. As a major result of our analysis we construct a prejudiced list of 34 proteins, relatively highly and uniquely detected in suction blister fluid as compared to serum, with established and putative characteristics as biomarkers. We conclude that suction blister fluid might potentially serve as a good alternative biomarker body fluid for diseases that involve the skin.

Assessment of serum β-trace protein (BTP) measurement in the prediction of glomerular filtration rate. Comparison with serum cystatin C

Serum BTP measurement is sometimes believed to be an alternative marker of glomerular filtration rate (GFR) assessment. The aim of the present work was to investigate the correlation between creatinine, cystatin C, and BTP values in sera and to compare the diagnostic efficacy for serum BTP and cystatin C with the glomerular filtration rate estimate. 25 individuals were tested. GFR was estimated from creatinine clearance, serum cystatin C and BTP and urine alpha-1 microglobulin, albumin, GMT and creatinine were measured. BTP values correlated with cystatin C (r = 0.75; p < 0.01), creatinine (r = 0.73, p < 0.01), GFR (r = -0.46; p = 0.02), urine alpha-1-microglobulin (r = 0.66; p < 0.01). The diagnostic efficacy of BTP for reduced GFR was insufficient and the calculation of GFR with BTP was not included in the regression model.