Birth-related increase in intracolonic hydrogen gas and nitric oxide as indicator of host-microbial interactions

Background: Bacterial colonization of the intestine early in life might have implications for allergy development. We studied early host-bacterial interactions in the gut by simultaneous measurements of hydrogen gas (H-2) and faecal short chain fatty acid pattern (SCFAs), i.e. bacterial products, as well as of nitric oxide (NO), a marker of mucosal immune activation. Methods: A novel minimally invasive technique was used for repeated measurements of luminal colonic H-2 and NO in 32 healthy newborn infants delivered vaginally or by Caesarean section. Luminal gas was sampled and analysed at five occasions: immediately after birth, day 1, days 3-5, 1 and 5-6 months after birth. Results: Colonic H-2, NO and faecal SCFAs were undetectable at birth. The H-2 and SCFAs appeared within 24 h and continued to increase during the 6 months follow-up. Nitric oxide remained very low until 3-5 days after birth at which time it markedly increased. In some apparently healthy infants NO transiently reached levels similar to those seen in adults with inflammatory bowel disease. Conclusion: Intracolonic measurements of H-2 and NO may be useful to monitor the developmental colonization process as well as mucosal responses.