Metabolism and toxicity of aluminum in renal failure

Aluminum levels were measured in a variety of tissues obtained from 36 control subjects, 30 nondialyzed uremic patients, 57 dialyzed uremic patients dying of a variety of different causes, and 38 dialyzed uremic patients dying of dialysis encephalopathy. The low aluminum levels consistently found in the control tissues support the fact that in health aluminum is largely excluded from the body. However, this ability to prevent aluminum accumulation is overcome with renal failure. Bone and liver aluminum levels were found to be significantly increased in 82% and 56% respectively in nondialyzed uremic patients and in 100% of the tissues examined from dialyzed uremic patients. In patients dying of dialysis encephalopathy, tissue aluminum levels were not only the highest but also affected in a different manner than that found in other dialyzed patients. It is suggested that dialysis encephalopathy occurs as a result of such rapid aluminum loading during dialysis that bone's ability to sequester this element is overcome, and it is shunted to liver and brain with resulting toxicity.