ULTRASTRUCTURAL IMMUNOCYTOCHEMISTRY OF COLLAGENOUS AND NONCOLLAGENOUSPROTEINS IN FAST-FROZEN, FREEZE-SUBSTITUTED, AND LOW-TEMPERATURE-EMBEDDED RENAL TISSUE IN ALPORT-SYNDROME

This paper describes the ultrastructural immunolocalization of the alp ha 2 chain of collagen IV, laminin, and the amino terminal propeptide of collagen I (N-Pro I) in glomeruli of rapidly frozen, freeze-substit uted, and low-temperature-embedded renal biopsy specimens from two cas es of Alport disease and from normal kidneys, The alpha 2 chain of col lagen IV is present in the whole thickness of the basement membrane in glomeruli of Alport patients, while it is limited to the subendotheli al portion of the basement membrane of normal glomeruli, Laminin has t he same distribution in both normal and Alport glomeruli, but is appar ently more concentrated along the basement membrane of normal glomerul i, N-Pro I is localized in mesangial areas and in the basement membran e in Alport cases, while it is not detected in normal glomeruli, These data suggest complex rearrangements of major constituents of the glom erular basement membrane network and demonstrate early deposition of f ibrillary collagen proteins in the matrix before the appearance of ban ded collagen fibres. This finding could be an indicator of early evolu tion towards glomerulosclerosis, (C) 1997 by John Wiley & Sons, Ltd.