Characterization of urinary keratin number 18 using a new assay

Area of Science:

• Biochemistry
• Urology
• Biomarker Discovery

Background:

• Keratin 18 is a low-molecular weight protein found in epithelial cells.
• Urinary biomarkers are increasingly used for non-invasive disease diagnosis.
• The presence and levels of keratin 18 in urine are not well-established.

Purpose of the Study:

• To develop and validate a new immunoradiometric assay for keratin 18 (IRMAK-18).
• To quantify low-molecular weight keratin 18 levels in the urine of healthy individuals.
• To investigate factors influencing keratin 18 detection in urine.

Main Methods:

• A novel immunoradiometric assay (IRMAK-18) was employed.
• Urine samples from 130 healthy volunteers were analyzed.
• Assay recovery and potential inhibitors in urine were assessed.

Main Results:

• Keratin 18 was detected in 79 out of 130 (approximately 61%) healthy volunteers.
• The average level of detected keratin 18 was 2.5 +/- 4.7 ng/ml.
• Urine creatinine levels may be a significant factor in interpreting keratin 18 measurements.

Conclusions:

• Low-molecular weight keratin 18 is detectable in the urine of a significant portion of healthy individuals.
• The IRMAK-18 assay shows potential for quantifying urinary keratin 18.
• Further research is needed to understand the clinical significance of urinary keratin 18 and optimize assay interpretation.