Quantitative studies of glomerular ultrastructure in human and experimental diabetes.

A brief review is given of glomerular structural changes in diabetes mellitus and in rats with induced diabetes. The stereological methods for obtaining quantitative structural data are mentioned, and references are given to the underlying theories as well as to more detailed descriptions of the practical performance. In short-term diabetes a glomerular hypertrophy is found with increase in the surface area of the capillaries, in parallel with an increase in glomerular filtration. In long-term diabetes mellitus the picture is dominated by accumulations of basement membrane: thickening of the peripheral basement membrane and expansion of the mesangial regions which hold large amounts of basement membrane material. Rats with a moderate diabetes show the early hypertrophy as well as long-term basement membrane thickening. Severely diabetic rats develop basement membrane thickening but do not show the early hypertrophy, which is therefore not a necessary condition for basement membrane thickening to occur.