Growth and appetite in chronic renal failure. Role of different protein diets

Effects of Intraperitoneal Infusion of Dextrose and Amino Acids on the Appetite of Rabbits

We studied the effect of Intraperitoneal Infusion of various volumes and concentrations of dextrose (D) and amino acid (AA) solutions, In a variety of peritoneal dialysis schedules on food Intake and biochemical profile in normal and uremic rabbits.

Following omentectomy, a peritoneal catheter was implanted. Animals had free access to food, and consumption was measured daily by weight of the remaining food in the cage.

We studied the effect of volume (30-50-100 mL/kg), dextrose concentration (0.5-1.5-2.5-4.25-6.6 g/dL) and AA (Travasol based) (2% in Dianeal or glucose-free solution).

Dialysis schedules Included once/day, twice/day, or four-daily exchanges similar to CAPD.

The durations of the exchanges were 4–6 weeks and in certain groups, amino acid exchanges for a week alternated with dextrose exchanges.

Our results Indicate the following: omentectomy and catheter implantation significantly decrease food Intake. There is a significant decrease In food Intake after initiation of dialysis that returns to baseline after 2–4 weeks while dialysis continues. Higher volumes (100 mL/kg) decrease food Intake significantly, especially with hypertonic solution of either D or AA. There was no difference in food Intake between D and AA Infusion In any amount of infused volumes.

Amino acids do not seem to have a suppressing effect on appetite. However, large volumes and hypertonicity reduce food Intake.

Contribution of experimental studies on the nutritional management of children with chronic renal failure

A few of the many reports of experimental chronic renal failure have been summarized. Anorexia and food selection have been studied in experimental uremia and the findings are comparable with those observed in uraemic children. The optimal dietary protein content for growth is close to the minimal requirement for "optimal" growth. Protein excess leads to growth retardation and renal deterioration in uraemic rats, at least with the commonly used dry diets. The increased water requirement may be more critical for growth than the blood urea level or acidosis, although this requires further investigation. Reduction of the dietary protein by 50% and supplementation with essential amino acids (EAA) results in growth similar to that of the 100% protein diet. There is no growth improvement despite low blood urea levels, but the renal parenchymal is preserved. Supplementation with nitrogen-free analogues is more frequently associated with defective growth; the optimal mixture remains to be defined, and to date, when nutrition is identical, nitrogen-free analogues offer no benefit for renal preservation compared with EAA. Sucrose-rich diets have adverse effects on uraemia. These effects are associated with fructose intolerance and with reduced energy storage in the liver. The precise metabolic alteration remains to be defined.