Dietary protein loading and the oral adsorbent AST-120 in the progression of chronic renal failure in the rat.

Excess protein intake enhances the progression of renal failure. The oral carbonaceous adsorbent, AST-120, was found experimentally and clinically to retard the progression of renal failure. This study was designed to determine whether deterioration of renal function by dietary protein loading can be prevented or mitigated by this oral adsorbent. Rats with uremia induced by partial renal infarction were fed a normal or high-protein diet for 70 days with or without AST-120, in which the inorganic phosphate content was adjusted to the same level. The survival rate deteriorated with the high dietary protein, but was improved from 30% to 100% with AST-120. Dietary protein loading reduced renal function, based on creatinine clearance. AST-120 improved renal function and renal histopathology not only in the normal diet group but in the high-protein group as well. The progression of renal failure induced by protein loading is thus shown to be prevented by oral AST-120. The mechanism for its action remains to be clarified.