GLOMERULAR NUMBER AND SIZE - FACTS AND ARTIFACTS

This review article is concerned with clinical and experimental data o n glomerular number and size and includes a critical discussion of the relevant stereological methods. There is considerable evidence suppor ting the view that the size of the glomerular filter, in tote, is rela ted to the inception and development of glomerular disease. Major dive rgences from the filter size are incompatible with normal structure an d function. Furthermore, the hypothesis has been put forward that ther e exists a subset of individuals with minor divergences from the norm that is more susceptible to glomerular disease than the general popula tion. Stereological methods for estimating glomerular number and mean glomerular size could be applied to set standard values. In addition, if the above hypothesis is confirmed, then they could identify on biop sy specimens the patients that belong to cohorts at risk of developing glomerular disease. Unfortunately, despite the development of new, ro bust methods for particle counting and size determination, such as the fractionator and the dissector, no universal standards of glomerular number and size have been agreed on to date. The major difficulties de pend on 1) establishing a standard protocol of tissue acquisition and processing and 2) defining possible variations across age, sex, and et hnic subgroups. The considerable effort required to overcome these dif ficulties should be rewarded, however, by important advances in the un derstanding of the morphogenesis of glomerular disease and in the diag nostic and prognostic yield of renal biopsy. (C) 1998 Wiley-Liss, Inc.