Increase In Mesangial Matrix Research Articles

Diabetes mellitus in the Chinese hamster. II. The evolution of renal glomerulopathy.

Light and electron microscopic studies were made of the renal glomeruli of 11 control Chinese hamsters, 4 siblings of diabetic hamsters, and 6 with spontaneous diabetes of varying age of onset, duration, and severity. Aging alone was associated with an increase in mesangial matrix and some degree of capillary dilatation and thickening of the basement membrane. In severe diabetes of early-onset, there was a marked change in mesangial cells, consisting of an increase in vesicles, multivesicular bodies, vacuoles, ghost-like appearance of the cytoplasm, and mitochondrial disorganization. Only in the more advanced stages was there an increase in the mesangial matrix. Initially, the basement membrane was thin, particularly in dilated capillaries. Measurements of the basement membrane in the later stages indicated that there were both thick and thin areas; increased thickness alone was not characteristic. Although similar findings developed progressively with age, mesangial cell alterations, coalescence and cystic dilatation and fusion of capillary loops in the glomeruli of young hamsters were characteristic findings of diabetic glomerulopathy. These findings were characteristic and disproportionately marked in any later stage of the disease. Coalescence of capillaries may have explained the decrease in the number of loops. The foot processes of the epithelial cells were well-preserved in all glomeruli and nodular lesions were not seen. There was no evidence in this series that litter-mates of diabetic animals developed such glomerular lesions in the absence of overt diabetes. An analogy was suggested between the dilatation and coalescence of glomerular capillaries associated with mesangial cell changes and the dilatation of retinal capillaries associated with degeneration of the supporting mural cells in man.