Preterm Birth Affects the Intestinal Response to Parenteral and Enteral Nutrition in Newborn Pigs

Abstract

Maturation of gastrointestinal (GI) function in neonates is stimulated by enteral nutrition, whereas parenteral nutrition induces GI atrophy and malfunction. We investigated whether preterm birth alters the GI responses to parenteral and enteral nutrition. Pigs were delivered either preterm (107 d gestation) or at term (115 d gestation) and fed total parenteral nutrition (TPN) or enteral sow's milk (ENT) for 6 d after birth. Immaturity of the preterm pigs was documented by reduced blood pH, oxygen saturation and neutrophil granulocyte function, impaired intestinal immunoglobulin G uptake from colostrum, and altered relative weights of visceral organs (small intestine, liver, spleen, pancreas, and adrenals). For both ages at delivery, increases occurred in pancreatic weight (30-75%) and amylase activity (0.5- to 13-fold) after birth, but much more in ENT than in TPN pigs (P < 0.05). Six days of TPN feeding was associated with reduced intestinal weight for both delivery groups (60% of values in ENT, P < 0.001), but only in term TPN pigs was the weight lower than at birth (-20%, P < 0.05). Likewise, it was only in term TPN pigs that intestinal maltase activity increased, compared with ENT, and the absorption of glucose and proline decreased. Only in preterm pigs did TPN feeding increase lactase activity (+50% compared with ENT, P < 0.05). For both delivery ages, the mRNA of lactase-phloridzin hydrolase and sodium-coupled glucose transporter 1 were increased in TPN, compared with ENT. In conclusion, the trophic effect of enteral vs. parenteral nutrition on the GI tract is also present after preterm birth, but the postnatal maturation of many GI functions is modified, compared with term birth. The effects of nutritional regimen on the maturation of the gut epithelium in neonates depend on gestational age at birth.

Physical activity level is impaired and diet dependent in preterm newborn pigs

“…associated with increases in key functions such as digestive enzyme activity, nutrient absorption, and immunological tolerance to bacterial colonization (27,(33)(34)(35). Our follow-up studies show that the difference in intestinal mass per body weight between preterm and term pigs on day 5 disappears over the following weeks but that the general deficits in body growth and many behavioral characteristics (regardless of diet during the first 5 d) remain until at least 4 wk of age (36).…”

Elective cesarean delivery affects gut maturation and delays microbial colonization but does not increase necrotizing enterocolitis in preterm pigs

“…Postnatal administration of exogenous corticosteroids to neonatal animals has been used to accelerate maturation of the intestine and other organs (35), and antenatal administration of glucocorticoids reduces the incidence of NEC in preterm hu- man infants (40). The higher cortisol levels of the newborn preterm VD appeared to accelerate gut maturation.…”

“…Rectal temperatures were recorded every 30 min for the first 4 h, and every 2 h thereafter until 10 h postpartum. Porcine serum, previously collected from pregnant sows, was administered to the pigs (4 ml/kg at 8 h, 5 ml/kg at 16 h, 10 ml/kg at 22 h postpartum) to provide passive immunization (40).…”

“…Distal intestinal villus and crypt depth (4) and activities of brush-border peptidases (aminopeptidase A, aminopeptidase N) and disaccharidases (lactase, maltase) are all measured as previously described (43). The activities of pancreatic enzymes (amylase, trypsin), stomach chymosin activity, and stomach acidity (pH) were measured following methods described previously (39,40).…”

Impact of gestational age on the clinical presentation and surgical outcome of necrotizing enterocolitis

“…1,2 Postnatally, profound developmental changes continue to occur in the GI tract of a neonate. 1,3 Many GI functions, including enhancement of absorptive capacity, efficiency of the gut-motor system, enrichment of the bile salt pool, and activity of digestive enzymes undergo considerable postnatal maturation that are most striking among preterm infants. 3,[4][5][6][7] Adaptive secretory and absorptive processes continue to mature after birth with postnatal growth of the neonate.…”