The cytoskeletal protein villin as a parameter for early detection of tubular damage in the human kidney.

Villin is a cytoskeletal protein of brush borders in the kidney and gut. After renal tubular cell injury the brushborder fragments are shedded into the tubular lumen and excreted with urine indicating renal tubular damage (so called "renal antigen" shedding). In urine villin appears as intact molecule (95,000 dalton) and as fragment with 70,000, 45,000 and 22,000 dalton. The major villin fragment (70,000 dalton) was purified after ammonium sulphate precipitation from urine of human renal transplant recipients. Final purification of the villin 70,000 dalton fragment was achieved by gel filtration with TSK 3000 SWG preparative grade. Purification was varified by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and western blotting.