Ultrastructural immunocytochemistry of collagenous and non-collagenous proteins in fast-frozen, freeze-substituted, and low-temperature-embedded renal tissue in Alport syndrome

Andrea Onetti Muda, Siavash Rahimi, Alessandra Renieri, Gianfranco Rizzoni, Laura Massella, Tullio Faraggiana

Research output: Contribution to journalArticle


This paper describes the ultrastructural immunolocalization of the α2 chain of collagen IV, laminin, and the amino terminal propeptide of collagen I (N-Pro I) in glomeruli of rapidly frozen, freeze-substituted, and low-temperature-embedded renal biopsy specimens from two cases of Alport disease and from normal kidneys. The α2 chain of collagen IV is present in the whole thickness of the basement membrane in glomeruli of Alport patients, while it is limited to the subendothelial portion of the basement membrane of normal glomeruli. Laminin has the same distribution in both normal and Alport glomeruli, but is apparently more concentrated along the basement membrane of normal glomeruli. N-Pro I is localized in mesangial areas and in the basement membrane in Alport cases, while it is not detected in normal glomeruli. These data suggest complex rearrangements of major constituents of the glomerular basement membrane network and demonstrate early deposition of fibrillary collagen proteins in the matrix before the appearance of banded collagen fibres. This finding could be an indicator of early evolution towards glomerulosclerosis.

Original languageEnglish
Pages (from-to)465-474
Number of pages10
JournalJournal of Pathology
Issue number4
Publication statusPublished - Aug 1997



  • α2(IV)
  • Alport syndrome
  • glomerulosclerosis
  • immunoelectron microscopy
  • kidney
  • laminin
  • N-Pro I

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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