Glomerular cell number in normal subjects and in type 1 diabetic patients

Background The number of cells in glomeruli has been a challenging measure, especially in human kidneys, with only a small amount of tissue obtained b y biopsy. However, the number of cells and their function are important det erminants of renal function in health and disease. Methods. Modern morphometric techniques have now provided the means to dete rmine the numerical density (N-v) and number (with a measure of glomerular volume) of endothelial cells, mesangial cells, and podocytes in plastic-emb edded renal tissue biopsied from nondiabetic subjects (N = 36) and type 1 d iabetic patients (N = 46) over an extended age range from childhood through late adult. Results, N-v values for all glomerular cells varied only slightly with age and did not change within the range of glomerular lesions of diabetes studi ed. Thus, the increase in glomerular volume during childhood to a steady le vel thereafter was the primary determinant of total glomerular cell number. The number of mesangial cells and endothelial cells increased with age, re flecting the increase in all cells, while the podocytes remained unchanged in number over all ages studied (10 to 69 years). Numbers of total glomerul ar cells, mesangial cells, and endothelial cells were not changed with diab etes, while podocytes were fewer in number in diabetic patients of all ages , with reduced podocyte numbers even in diabetes of short duration. Conclusions. The essentially constant glomerular cell density in nondiabeti c and diabetic subjects under different circumstances possibly indicates an underlying propensity for the glomerulus to regulate its architecture to m aintain a constant number of cells per volume, no matter the size Of the gl omerulus or the severity of diabetic nephropathy studied in this set of pat ients. The: reductions in podocyte numbers in both younger and older diabet ic patients indicate a significant risk for functional abnormalities as dia betic nephropathy progresses. Moreover, these observations do not support t he suggestion of marked increases in glomerular cell number (and especially mesangial cells) with the development and progression of diabetic nephropa thy.