Comparison of High Molecular Weight Beta Trace Protein and Low Molecular Weight Beta Trace Protein for the Assessment of Kidney Function in Patients with Chronic Kidney Disease

Chronic kidney disease (CKD) can be defined as either decreased kidney function (GFR < 60ml/min/1.73m²) or persistent kidney damage (indicated by markers of kidney damage) for 3 or more months. bTP is a monomeric glycoprotein with 168 amino acids and a molecular mass variation. Low beta trace protein isoform (L-BTP), the smaller “brain” origin isoforms, predominate in the CSF; whereas, high beta trace protein isoform (H-bTP), the larger “plasma” type glycoforms, predominate in serum and urine. These multiple isoforms certainly have implications for bTP measurement.

Current study was aimed to compare the clinical usefulness of serum levels of H-bTP isoform for the detection of renal dysfunction in patients with chronic kidney disease (CKD) and making a comparison with levels of L-bTP.

The study included 150 patients divided into three groups with a wide range of renal dysfunction that encompassed CKD stages from (I-IV).

The obtained data showed that H-bTP was highly correlated (Pearson test) with measured GFR (mGFR) (r= 0.86) in logarithmic linear model, and correlated with L-bTP (r= 0.209). The results of this study showed that H-BTP had a significant higher concentration and strongest correlation with mGFR in comparison with L-bTP isoform.

H-bTP (and not the L-bTP isoform of brain origin) may be a useful and reliable serum marker for identifying the magnitude of renal dysfunction in patients with CKD and may have its place besides serum cystatin C and creatinine as an alternative endogenous GFR marker.