Three-dimensional studies of acellular glomerular basement membranes in dense-deposit disease

After digestion removed the cells from glomeruli of frozen kidney tissue, we employed scanning electron microscopy to examine the acellular glomerular basement membranes (AGBM) from normal kidneys and from kidneys of patients with dense-deposit disease (DDD). The AGBM showed previously unrecognized three-dimensional patterns of pathologic changes. When compared to normal controls, the AGBM in DDD appeared "rigid" and thickened. Other pathologic features included coarsely granular or undulating epimembranous surfaces punctuated by single or clustered crater-like deformities. Although epimembranous crater-like deformities have been observed in other glomerulopathies, the combination of "rigid"-appearing AGBM punctuated by crater-like deformities is thus far unique to DDD.