Small bowel mucosal dysfunction in patients with cystic fibrosis

Area of Science:

• Gastroenterology
• Pediatric Medicine
• Biochemistry

Background:

• Cystic Fibrosis (CF) is a genetic disorder affecting multiple organs, including the intestines.
• Gluten-induced enteropathy (celiac disease) involves intestinal damage due to gluten exposure.
• Malabsorption is a common complication in both CF and gluten-induced enteropathy.

Purpose of the Study:

• To assess intestinal disaccharidase and L-ALA-L-Phe hydrolase activities in children with CF and gluten-induced enteropathy.
• To evaluate the intestinal uptake of specific amino acids in these pediatric populations.
• To determine if intestinal dysfunction contributes to malabsorption in cystic fibrosis.

Main Methods:

• Jejunal biopsies were analyzed from 37 children with CF, 16 with gluten-induced enteropathy, and 18 controls.
• Disaccharidase and L-ALA-L-Phe hydrolase activities were measured.
• Intestinal uptake of three 14C-labeled amino acids (lysine, phenylalanine, cycloleucine) was assessed.

Main Results:

• Patients with gluten-induced enteropathy showed significantly reduced enzyme activities and amino acid uptake compared to controls.
• Cystic fibrosis patients exhibited significantly reduced lactase and L-ALA-L-Phe hydrolase activities (p < 0.01).
• Hypolactasia was present in 23% of CF patients; phenylalanine and cycloleucine uptake was reduced in CF, while lysine uptake was normal.

Conclusions:

• Both gluten-induced enteropathy and cystic fibrosis are associated with impaired intestinal enzyme activity.
• Reduced amino acid uptake in CF suggests a primary intestinal component to malabsorption.
• These findings highlight the intestinal involvement in the pathophysiology of cystic fibrosis.