Serum Levels of Tumor Associated Trypsin Inhibitor (TATT) and Glomerular Filtration Rate

Abstract

TATI (tumor associated trypsin inhibitor) is a low molecular weight protein employed as a tumor marker. To evaluate the role of the kidney in the clearance of TATI, we studied the rat kidney uptake of ¹²⁵I-TATI. Total body scan demonstrated a high radioactivity in the kidneys of the rats and none in other organs. The relationship between serum TATI and glomerular filtration rate (GFR) was studied in man. For comparison serum β₂-microglobulin (β₂M) arid plasma creatinine were also determined The decrease in GFR was accompanied by an increase in the other parameters. Serum TATI increased in patients with renal failure (GFR <20 mL/min) 12.4 times with respect to subjects with normal renal function (p <0.001, non-parametric Mann-Whitney test), β₂M increased 7.6 times (p <0.001) and creatinine 4.7 times (p <0. 001). The increase in TATI is statistically significant already in patients with GFR 60–40 mL/min (p <0.005). These results suggest that TATI is handled by the kidney. It is a sensitive marker of reduction in renal function.

Key Words:

• Glomerular filtration rate
• Low molecular weight proteins