Nephrotic syndrome and renal insufficiency in association with amyloidosis: a correlation between structure and function.

The following results were obtained by correlating light and electron microscopic findings from 85 cases of glomerular renal amyloidosis with clinical parameters: 1. Amyloid masses deposited in the glomeruli do not represent an effective filtration barrier, i.e., the formation of primary urine is not significantly influenced even by extensive amyloid masses in the glomeruli; protein retention is first observed when the glomerular capillaries are almost totally obliterated. 2. Once the nephrotic syndrome has developed in association with glomerular renal amyloidosis, it shows no tendency for remittance, despite progressing renal insufficiency. 3. The reason for this persistance of the nephrotic syndrome, despite increasing renal insufficiency, is a progressive reduction in the capacity of the tubules for protein reabsorption in the presence of increasing interstitial fibrosis of the kidney. 4. Interstitial fibrosis of the kidney cortex leads to increasing impairment in the oxygen and energy supply to the tubule cells together with considerable functional deterioration which, in addition to other metabolic disturbances, also results in a reduced capacity for protein reabsorption.