Diet- and Colonization-Dependent Intestinal Dysfunction Predisposes to Necrotizing Enterocolitis in Preterm Pigs

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

“…The higher cortisol levels of the newborn preterm VD appeared to accelerate gut maturation. Specifically, the gut characteristics of the VD pigs differed more than expected from those of the CS pigs based on the 30-to 36-h longer gestation and approached those of newborn term CS pigs (42). The findings suggest that VD accelerates maturation of some gut parameters in newborn preterm pigs, potentially via an associated cortisol surge.…”

“…This is evident from the lack of NEC in preterm gnotobiotic pigs fed formula (42). The patterns of bacterial colonization are particularly important for preterm neonates because of their increased sensitivity to bacterial colonization (9,29), with aberrant bacterial growth causing severe gut dysfunction and disease (15,37).…”

“…A standard protocol was used to prepare and evaluate the purity of BBMV prepared from the frozen tissue and to measure rates of nutrient (glucose, lysine, leucine, proline) accumulation (42,49). The ability of the SI to absorb the protein macromolecules BSA (A-4503, 5.0 g/l; Sigma, St. Louis, MO) and bovine IgG (bIgG, G-5009, Sigma; 5.0 g/l) was measured in vitro, as previously described (41).…”

“…commonly located in the distal small intestine (SI) and colon (22,42). Despite precautions and the initial administration of total parenteral nutrition (TPN), NEC remains the most common gut disease afflicting preterm neonates (9).…”

Transforming growth factor-β2 and endotoxin interact to regulate homeostasis via interleukin-8 levels in the immature intestine

“…This implies that LPS may play a more critical role than TGF-␤2, with possible dose-dependent effects on IL-8 secretion, and that other bioactive components in colostrum may maintain the low IL-8 levels in COLOS pigs. Although intestinal TLR-4 levels are not lower in colostrum-than formula-fed preterm pigs (4), LPS may be less accessible for TLR-4 binding and activation to act in synergy with TGF-␤2 to induce IL-8 in COLOS, since we previously detected very few bacteria attached to the intestinal tissue of COLOS compared with IF pigs (35). This may be because of limited LPS diffusion and bacterial mobility caused by enhanced mucus production in the immature intestine of COLOS pigs (31).…”