Nitroglycerin attenuates the bowel damage of necrotizing enterocolitis in a rabbit model

State-of-the-art review and update of in vivo models of necrotizing enterocolitis

NEC remains one of the most common causes of mortality and morbidity in preterm infants. Animal models of necrotizing enterocolitis (NEC) have been crucial in improving our understanding of this devastating disease and identifying biochemical pathways with therapeutic potential. The pathogenesis of NEC remains incompletely understood, with no specific entity that unifies all infants that develop NEC. Therefore, investigators rely on animal models to manipulate variables and provide a means to test interventions, making them valuable tools to enhance our understanding and prevent and treat NEC. The advancements in molecular analytic tools, genetic manipulation, and imaging modalities and the emergence of scientific collaborations have given rise to unique perspectives and disease correlates, creating novel pathways of investigation. A critical review and understanding of the current phenotypic considerations of the highly relevant animal models of NEC are crucial to developing novel therapeutic and preventative strategies for NEC.

The epidemiology and pathogenesis of necrotizing enterocolitis

Necrotizing enterocolitis (NEC), a syndrome characterized by crepitant necrosis of the bowel, has emerged as the most common neonatal gastrointestinal emergency in many countries of the world. In the United States, NEC strikes 1 to 8% of patients admitted to neonatal intensive care units, almost all of whom are premature infants. The incidence is low in certain countries wity a low premature birth rate, e.g., Japan. Two theories of pathogenesis are: the Santulli theory, which implicates three factors: ischaemia, bacteria and substrate; and the Lawrence theory, which stresses the injurious role of bacterial toxins on the immature gut of the preterm infant. Clinical and experimental evidence support each of the theories, but neither theory can explain certain clinical phenomena, particularly the resistance to NEC manifested by more than 90% of preterm infants, who never develop the syndrome. A unifying hypothesis of pathogenesis and a mathematical model of NEC are outlined. Because clustering of cases may occur, the design of clinical trials of preventive measures for NEC must include simultaneous control infants.

Necrotizing enterocolitis increases the bone resorption in premature infants

BACKGROUND

Necrotizing enterocolitis is a common neonatal gastrointestinal disease that affects approximately 10% of premature infants less than 1500 g. The average mortality is 20-40% and survivors may present with diarrhea or malabsorption, intestinal strictures and fistulas, feeding abnormalities and failure to thrive. It is not clear whether the higher incidence of this gastrointestinal disease in premature infants contributes to the risk of osteopenia of prematurity.

AIM

To examine bone turnover state in premature infants who had a necrotizing enterocolitis attack during postnatal period.

STUDY DESIGN AND SUBJECTS

We examine the bone turnover markers in infants with necrotizing enterocolitis and compare them with infants with sepsis. Forty-one premature infants participated in the study and were divided into three groups. In group I, there were 14 premature infants who developed necrotizing enterocolitis with negative blood culture during their hospitalization. In group II, there were 12 premature infants who developed sepsis during their hospitalization. Age-matched 15 premature infants who were given parenteral nutrition served as control group (group III). Blood samples and 6-h urine samples were obtained for bone turnover markers and calcium, phosphorous, creatinine and 25-hydroxy vitamin D between the day 20 and 25. Bone osteoblastic activity was assessed by measurement of serum osteocalcin. Bone resorption was assessed by measurement of serum levels of beta-CrossLaps and urinary deoxypyridinoline.

RESULTS

There were no significant differences in bone osteoblastic activity among the groups, but bone resorption markers were significantly higher in infants with necrotizing enterocolitis compared to other groups (p < 0.016).

CONCLUSION

Necrotizing enterocolitis increases the bone resorption in premature infants. It may be related with reduced glucagon like peptide-2 levels, a new intestinal hormone that is primary secreted from distal small intestine.

Necrotizing enterocolitis, pathogenesis and the protector effect of prenatal corticosteroids

Necrotizing enterocolitis is the most frequently occurring gastrointestinal disorder in premature neonates. Animal models of necrotizing enterocolitis and prenatal administration of cortisone have demonstrated that cortisone may accelerate maturation of the mucosal barrier, therefore reducing the incidence of this gastrointestinal disorder. The authors present a review of the literature of the most important risk factors associated with necrotizing enterocolitis, such as inflammatory gastrointestinal mediators, enteral feeding and bacterial colonization, and immaturity of the gastrointestinal barrier, and we emphasize the necessity for additional studies to explore the prenatal administration of cortisone as a preventive strategy for necrotizing enterocolitis.

Arginine supplementation prevents necrotizing enterocolitis in the premature infant

OBJECTIVES

To determine whether supplementation with L -arginine reduces the incidence of all stages of necrotizing enterocolitis (NEC) in premature infants with birth weight < or =1250 g and gestational age < or =32 weeks.

STUDY DESIGN

In a randomized, double-blind, placebo-controlled study, 152 premature infants were prospectively, randomly assigned to receive either supplemental L -arginine (1.5 mmol/kg per day; n =75 [group A]) or placebo (control group; n = 77 [group B]) with oral feeds/parenteral nutrition during the first 28 days of life. Nutrient intake, plasma ammonia, arginine, and amino acid concentrations were measured in all infants at days 3, 14, and 28 and at the time of diagnosis of NEC.

RESULTS

NEC developed in 5 infants in group A compared with 21 infants in group B (P <.001). Arginine intake and plasma arginine concentrations were similar in both groups at study entry and (as expected) increased in group A at days 14 and 28. Plasma arginine concentrations were lower in both groups at time of diagnosis of NEC. No significant differences in maternal and neonatal demographics, nutrient intake, plasma ammonia and total and essential amino acid concentrations were present between the two groups.

CONCLUSIONS

Arginine supplementation (1.5 mmol/kg per day) in premature infants reduces the incidence of all stages of NEC.

Necrotizing enterocolitis in the full-term neonate

Necrotizing enterocolitis (NEC) is a relatively common disorder of multifactorial aetiology that primarily affects preterm newborns, but has been reported to occur in the full-term neonate as well. This review focuses on known and recent developments in the epidemiology, pathogenesis, diagnosis, management and prevention of NEC in the full-term neonate.

Necrotiserende enterocolitis

Necrotiserende enterocolitis (nec) is een zeer ernstig verlopende ziekte van het darmkanaal. De incidentie van nec op de neonatale intensive care varieert van 1 tot 5%. De etiologie van nec is onbekend, maar er zijn aanwijzingen dat multipele factoren in staat zijn nec te veroorzaken via activatie van ontstekingsmediatoren, waarvan plaatjesactiverende factor (paf) één van de belangrijkste is. De geactiveerde cascade resulteert uiteindelijk in ontsteking en necrose van de darm. Prematuriteit is de belangrijkste risicofactor voor nec. Andere risicofactoren zijn infectie, ischemie van de darm en blootstelling aan enterale voeding. nec treedt het meest op bij extreem prematuren en prematuren met een groeiachterstand (gewicht minder dan de 10e percentiel). nec kent een ernstig beloop en uiteindelijk overlijdt 30% van de patiënten. Ondanks dat diverse preventiestrategieën bekend zijn, is men niet in staat nec te elimineren. In de toekomst zijn nieuwe ontwikkelingen te verwachten op het gebied van ontstekingsmediatoren.

Necrotizing enterocolitis in infants with very low birth weight

Necrotizing enterocolitis (NEC) is a disease in which the primary risk factor is prematurity. Despite, and partially as a result of, the tremendous strides neonatal care has taken, it is a major cause of morbidity and mortality of the newborn. The infant with very low birth weight is particularly susceptible, and the management of the condition in this group differs somewhat from other neonates. The outcomes continue to improve, but there are significant sequelae. Prevention, which would be the best "cure," is elusive, in no small part because of the multifactorial nature of the etiology of NEC.