Specificity of infant digestive conditions: Some clues for developing relevant in vitro models
Résumé
Digestion of nutrients is an essential function of the newborn infant gut to allow growth and development and understanding infant digestive function is essential to optimize nutrition and oral drug delivery. Ethical considerations prohibit invasive in vivo trials and as a consequence in vitro assays are often conducted. However, the choice of in vitro model parameters are not supported by an exhaustive analysis of the literature and do not mimic precisely the digestive conditions of the infant. This presentation summarizes the studies which characterized the gastro-duodenal conditions in full-term or pre-term infants of variable postnatal age from birth up to six months. Both developmental factors and feeding specificities of infant (< 6 months) result in very singular conditions of digestion as compared to adults. The immaturity of gastric protease (pepsins) on one side, and pancreatic lipolytic enzymes (Pancreatic Triglyceride Lipase, Phospholipase A2) and amylase on the other side,
are noticeable features of the infant digestive systems. But non-enzymatic parameters (milkbased diet, frequency of feeding, bile salt concentrations) also affect infants digestive process. These parameters should be taken into account by food scientists to make wellconsidered choice of parameters for in vitro and in silico models mimicking the infant gastrointestinal tract, instead of using general conditions of digestion which reflects the mature adult digestive system.