Aldolase activities of the small intestinal mucosa in malabsorption states and hereditary fructose intolerance

Abstract

Determination of aldolase activity in intestinal biopsy material offers a diagnostic alternative to liver biopsy in hereditary fructose intolerance (HFI). This diagnostic method could be validated by analysis of intestinal biopsies from eight patients with HFI. With the substrate fructose-1-phosphate (fru-1-p) we found 0.3±0.3 (x±SD) U/g of protein, with the substrate fructose-1,6-diphosphate (fru-1,6-p) 3.8±2.7 U/g of protein were measured. These results differ clearly from control activities (substrate = fru-1-p: 7.4±1.9 U/g of protein; substrate=fru-1,6-p: 13.9±4.3 U/g of protein). As the performance of the intestinal biopsy—in contrast to the liver biopsy—is virtually free of complications, it is recommended as the diagnostic method of choice in this disease.

Aldolase activities were also determined in 40 intestinal biopsies from children with different malabsorption states: celiac disease (n=13), cow's milk protein intolerance (n=9), postinfectious syndrome (n=10), giardiasis (n=8). The activities differed clearly from our results in hereditary fructose intolerance. In celiac disease, cow's milk protein intolerance and postinfectious syndrome characteristic activity patterns were obtained: activities with fru-1,6-p were increased (celiac disease 17.2±5.7 U/g of protein; cow's milk protein intolerance 19.5±7.0 U/g of protein) or in the normal range (postinfectious syndrome 14.0±3.1 U/g or protein); activities with fru-1-p were decreased (celiac disease 2.3±1.0 U/g of protein; cow's milk protein intolerance 3.4±1.3 U/g of protein; postinfectious syndrome 5.0±0.8 U/g of protein). These results are discussed on the basis of aldolase isoenzyme distribution in the small intestinal mucosa.