Intestinal exfoliated cells in infant diarrhoea: changes in cell renewal and disaccharidase activities

Area of Science:

• Pediatric Gastroenterology
• Molecular Biology
• Cell Biology

Background:

• Lactase deficiency, a marker of jejunal dysfunction post-infant E. coli enteropathy, often presents with normal villous morphology.
• Previous hypotheses focused on impaired lactase biosynthesis, neglecting the role of epithelial cell turnover in mucosal lactase levels.

Purpose of the Study:

• To investigate the relationship between jejunal cell renewal and disaccharidase activities in infants with residual lactose malabsorption after E. coli infection.
• To explore the influence of altered epithelial cell turnover on mucosal lactase levels during recovery.

Main Methods:

• Analysis of exfoliated jejunal cells collected via lumenal perfusion in ten infants with lactose malabsorption.
• Quantification of DNA and protein exfoliation to assess cell renewal activity.
• Measurement of brush border disaccharidase activities, specifically lactase and sucrase, in exfoliated cells.

Main Results:

• Significant increases in DNA and protein exfoliation were observed during recovery, indicating heightened cell renewal.
• Brush border lactase and sucrase activities in exfoliated cells increased significantly during recovery from malabsorption.
• Lactase activity was initially four times more deficient than sucrase; both enzymes increased at similar rates, with lactase normalizing later.

Conclusions:

• Altered jejunal epithelial cell turnover plays a role in residual lactase deficiency after E. coli enteropathy.
• The recovery of lactase and sucrase activities is linked to increased cell renewal and cell age.
• The findings suggest a relationship between the levels of sucrase and lactase and the age of jejunal epithelial cells.