Problems in the treatment of malabsorption in CF

Abstract

). Problems in the treatment of malabsorption in CF. Acta Paed Scand Suppl 317.Several factors play a role in the cause of malabsorption in CF. Besides the enzyme deficiency in the secretion of the exocrine pancreas, decreased bile-salt concentration in the gut may also be an important factor in the fat malabsorption. The contribution to the fat absorption by other lipases, such as lingual lipase and gastric lipase, remains to he proved. The therapeutic measures are only partly effective because of the breakdown of swalled enzymes by gastric acid. Some improvement is reached by using a new acid-resistant coating for the enzyme supplement. Newly developed and essential for its success is the application of small coated particles to prevent retention in the stomach, and the easy breakdown of the coating in an alkaline solution. The treatment of the bile salt deficiency has not been successful until now. A trial with additional Tween 80, with the option of supplementing the detergent activity which was found to he successful in Crohn disease, was without marked success.Malabsorption is one of the more serious problems in CF. The fat and protein digestion and absorption and, to a lesser extent, also the carbohydrate digestion are disturbed. The disorder of the intraluminal digestion is caused mainly by insufficiency of the exocrine pancreas, in particular by the decreased secretion of bicarbonate, lipase and trypsin. Moreover, the digestion is disturbed by a deficiency of bile salts in the proximal gut which results in a reduced emulsifying capacity and a decrease in enzyme induction.The supposed high viscosity of the intestinal fluids may hamper the transport of digested products. This would explain many of the CF-related disorders, such as intestinal obstruction and ileus symptoms and the thick unstirred water layer on the brushborder of the epithelium (1). Finally, a specific intracellular transport defect of bile salts has recently been suggested (2).In the following survey, we consider the role of these factors in C F patients. EnzymesIn the majority of C F patients, pancreatic enzyme deficiency is such that both fat and protein absorption is seriously diminished. The main enzymes involved are lipase, the lipase-colipase complex, lingual lipase, phospholipase, and the protein and carbohydrate splitting enzymes. This was repeatedly shown, among others, by Wong et al. (3) using the pancreozymin secretin stimulation test. Their results revealed that the enzyme activity of lipase reached only 3 % of normal levels, whereas trypsin and chymotrypsin amounted to 30 %. However, the usual treatment consisting of the administration of supplemental pancreas extract is only partly effective. Fat absorption does improve, but without reaching a normal level. In this connection, DiMagno et al. (4) carried out a study of enzyme activity in the duodenum following the administration of pancreatic extracts. In the distal part of the duodenum, this resulted in 22% of the administered dose for trypsin activity and only 3 % for the l...

Biochemical assessment of the nutritional status of cystic fibrosis patients treated with pancreatic enzyme extracts

“…Despite regular pancreatic enzyme therapy, impaired nutritional status persisted in several patients, as confirmed by biochemical evidence of malnutrition. This impaired status could not have been due to inactivation of the enzymes in the stomach because the pancreatic enzyme supplements are in the form of enteric-coated microspheres that prevent enzyme degradation (10,12,21). The partial response to pancreatic enzyme therapy could, however, have been caused by inactivation of these enzymes in the small intestine as result of a low duodenal pH caused by pancreatic impairment of bicarbonate secretion.…”

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“…Malabsorption in CF can be improved by giving pancreatic extracts with meals [6,97]. An important advance has been enteric coated microspheres resistant to acid which significantly enhances the enzyme activity in the duodenum.…”

Mechanisms of lipid malabsorption in Cystic Fibrosis: the impact of essential fatty acids deficiency

“…However, AA and DHA decrease the secretion of bile-salt dependent lipase, but without directly impairing the biosynthesis of this enzyme. AA alters the transport of the enzyme toward the cytosol, leading to the retention of bile-salt dependent lipase in microsomes [127]. It is likely that much attention must be paid to phospholipases and CET in CF in view of their role in fat absorption.…”