KIM-1 Expression Predicts Renal Outcomes in IgA Nephropathy

Clin Exp Nephrol. 2013 Jun;17(3):359-64. doi: 10.1007/s10157-012-0707-2. Epub 2012 Nov 8.

Abstract

Background: Kidney injury molecule-1 (KIM-1) is a sensitive biomarker for proximal tubular injury. Recently, a few studies have shown that urinary KIM-1 has clinical implications in IgA nephropathy (IgAN). We performed this study to determine whether tissue KIM-1 has clinical implications for predicting long-term outcome and whether urinary KIM-1 is correlated with tissue KIM-1 and kidney injury in IgAN patients.

Methods: We assessed the prognostic prediction capability of tissue KIM-1 expression in 69 adult patients with IgAN retrospectively. Renal biopsies from all patients were scored by a pathologist who was blinded to the clinical data for the pathologic variables. The primary outcome was the composite of a 50 % reduction in eGFR or end-stage renal disease. Tissue KIM-1 expression was assessed semiquantitatively by counting the stained tubules per 100× power field; 0 tubule indicates grade 0; 1-5 tubules, grade 1; 6-10 tubules, grade 2; and more than 10 tubules, grade 3. Comparing urinary KIM-1 and tissue KIM-1 expression, 50 consecutive IgAN patients were prospectively enrolled to measure urinary KIM-1 levels and examine their biopsy specimens by KIM-1 immunohistochemistry.

Results: Univariate analysis showed that tissue KIM-1 expression was associated with the renal outcome in IgAN. Multivariate regression analysis, as the relationship of tissue KIM-1 with prognosis, was consistent. Proteinuria at biopsy and tissue KIM-1 grade 3 were shown to have a prognostic value. The concentration of urinary KIM-1/Cr in patients with IgAN was significantly higher than that in the normal controls.

Conclusion: Tissue KIM-1 expression is an independent predictor of adverse renal outcomes in IgA nephropathy patients.

MeSH terms

  • Adult
  • Biomarkers / urine*
  • Female
  • Glomerulonephritis, IGA / complications*
  • Glomerulonephritis, IGA / pathology
  • Hepatitis A Virus Cellular Receptor 1
  • Humans
  • Immunohistochemistry
  • Kidney / pathology*
  • Male
  • Membrane Glycoproteins / metabolism*
  • Membrane Glycoproteins / urine
  • Middle Aged
  • Prognosis
  • Prospective Studies
  • Receptors, Virus / metabolism*
  • Retrospective Studies

Substances

  • Biomarkers
  • HAVCR1 protein, human
  • Hepatitis A Virus Cellular Receptor 1
  • Membrane Glycoproteins
  • Receptors, Virus