Cow's milk protein-specific T-helper type I/II cytokine responses in infants with necrotizing enterocolitis

Necrotizing enterocolitis: current understanding of the prevention and management

Necrotizing enterocolitis (NEC) is one of the diseases in neonates, with a high morbidity and mortality rate, especially in preterm infants. This review aimed to briefly introduce the latest epidemiology, susceptibility factors, and clinical diagnosis and presentation of NEC. We also organized new prevention strategies by risk factors according to different pathogeneses and then discussed new treatment methods based on Bell's staging and complications, and the classification of mild to high severity based on clinical and imaging manifestations. Such a generalization will help clinicians and researchers to gain a deeper understanding of the disease and to conduct more targeted classification, grading prevention, and exploration. We focused on prevention and treatment of the early and suspected stages of NEC, including the discovery of novel biomarkers and drugs to control disease progression. At the same time, we discussed its clinical application, future development, and shortcomings.

Exploring the links between necrotizing enterocolitis and cow's milk protein allergy in preterm infants: a narrative review

A broad range of allergic disorders and intolerance are associated with cow's milk protein in the infant diet. Allergy and intolerance to cow's milk proteins are commonly recognized in the healthy term infant, and the prevalence cow's milk protein intolerance (CMPI) varies widely but 5 challenge confirmed studies free from selection bias ranged from 1.9%-4.9%. These disorders are classified by the presence of IgE, non-IgE or T-cell-mediated signaling. Additionally, the severity of these adverse food reactions can range from mild gastrointestinal symptoms to severe sepsis-like episodes, as in the case of food protein-induced enterocolitis syndrome (FPIES). Food protein-induced intolerance in the healthy young infant lies in stark contrast to enterocolitis that typically occurs in the preterm neonate. Necrotizing enterocolitis (NEC) is a distinct progressive disease process, usually characterized by a high mortality rate, with a risk of death from 30% to 50%. While its exact etiology is unclear, its main triggers include formula (cow's milk protein), hypoxia, perfusion-related issues, and unregulated inflammation in the premature intestine. The distinction between NEC and cow's milk protein intolerance is difficult to discern in some cases. In the late preterm population, infants with colitis can have both NEC and cow's milk intolerance on the differential. In infants with multiple episodes of mild NEC, cow's milk protein intolerance may be the underlying diagnosis. In this review, we compare the pathophysiological characteristics, diagnosis and treatment of disorders of cow's milk protein intolerance with the entity of preterm NEC. This review highlights similarities in both entities and may inspire future cross-disciplinary research.

Comparative effectiveness of liquid human milk fortifiers: A systematic review and meta-analysis

OBJECTIVE

To determine the effectiveness of liquid human milk fortifiers (HMFs) derived from exclusive HM or hydrolyzed protein on growth, necrotizing enterocolitis (NEC), or late-onset sepsis in North American very low-birth-weight (VLBW) infants compared with powder HMFs (control).

METHODS

Prospective trials published between 2009 and 2020 were systematically reviewed, and meta-analysis was conducted by using a random-effects model.

RESULTS

Five studies were identified for up to 591 participants across 39 centers. Study treatments included whey or casein hydrolysate HMF and exclusive HM HMF. Infants fed whey or casein hydrolysate HMF had growth differences compared with the control. No differences were found across treatments in regard to NEC or sepsis.

CONCLUSION

Very low-quality evidence suggests greater linear growth in VLBW infants fed whey hydrolysate liquid HMF, as well as greater weight gain in those fed casein hydrolysate HMF, compared with the control. Additional prospective, multicenter randomized controlled trials are needed to confirm these estimates because of sparsity of evidence. There is insufficient evidence to support HMF decisions regarding NEC or late-onset sepsis prophylaxis.

Optimizing Nutritional Strategies to Prevent Necrotizing Enterocolitis and Growth Failure after Bowel Resection

Necrotizing enterocolitis (NEC), the first cause of short bowel syndrome (SBS) in the neonate, is a serious neonatal gastrointestinal disease with an incidence of up to 11% in preterm newborns less than 1500 g of birth weight. The rate of severe NEC requiring surgery remains high, and it is estimated between 20–50%. Newborns who develop SBS need prolonged parenteral nutrition (PN), experience nutrient deficiency, failure to thrive and are at risk of neurodevelopmental impairment. Prevention of NEC is therefore mandatory to avoid SBS and its associated morbidities. In this regard, nutritional practices seem to play a key role in early life. Individualized medical and surgical therapies, as well as intestinal rehabilitation programs, are fundamental in the achievement of enteral autonomy in infants with acquired SBS. In this descriptive review, we describe the most recent evidence on nutritional practices to prevent NEC, the available tools to early detect it, the surgical management to limit bowel resection and the best nutrition to sustain growth and intestinal function.

Cow's Milk Protein Allergy in Term and Preterm Infants: Clinical Manifestations, Immunologic Pathophysiology, and Management Strategies

Cow's milk allergy is a common food allergy among infants. Symptoms of cow's milk allergy are wide-ranging and depend on the mechanism involved. There are immunoglobulin E (IgE)-mediated, non-IgE-mediated, and mixed mechanisms of food allergy. Symptoms of IgE-mediated cow's milk allergy may be mild or may progress to anaphylaxis, which can be life-threatening. Non-IgE-mediated allergy includes food protein-induced allergic proctocolitis (FPIAP), food protein-induced enterocolitis syndrome, food protein-induced enteropathy, and Heiner syndrome (pulmonary hemosiderosis). These diagnoses comprise about half of all cow's milk allergies. The most common manifestation of cow's milk allergy in infants is FPIAP. FPIAP is commonly seen in healthy, full-term infants who present with rectal bleeding and are otherwise well-appearing. This can occur in both formula-fed and exclusively breastfed infants. Food proteins secreted in maternal breast milk can contribute to the development of these symptoms. Maternal cow's milk elimination diet is often successful in helping resolve symptoms. A period of reintroduction of cow's milk resulting in re-emergence of symptoms in stable asymptomatic infants is an excellent diagnostic tool to confirm a cow's milk allergy. Preterm infants are susceptible to food allergy, as demonstrated from several case reports of necrotizing enterocolitis-like illnesses that responded clinically to cow's milk elimination. Further study is needed about food allergy in the preterm infant population.

Nutrition in Necrotizing Enterocolitis and Following Intestinal Resection

This review aims to discuss the role of nutrition and feeding practices in necrotizing enterocolitis (NEC), NEC prevention, and its complications, including surgical treatment. A thorough PubMed search was performed with a focus on meta-analyses and randomized controlled trials when available. There are several variables in nutrition and the feeding of preterm infants with the intention of preventing necrotizing enterocolitis (NEC). Starting feeds later rather than earlier, advancing feeds slowly and continuous feeds have not been shown to prevent NEC and breast milk remains the only effective prevention strategy. The lack of medical treatment options for NEC often leads to disease progression requiring surgical resection. Following resection, intestinal adaptation occurs, during which villi lengthen and crypts deepen to increase the functional capacity of remaining bowel. The effect of macronutrients on intestinal adaptation has been extensively studied in animal models. Clinically, the length and portion of intestine that is resected may lead to patients requiring parenteral nutrition, which is also reviewed here. There remain significant gaps in knowledge surrounding many of the nutritional aspects of NEC and more research is needed to determine optimal feeding approaches to prevent NEC, particularly in infants younger than 28 weeks and <1000 grams. Additional research is also needed to identify biomarkers reflecting intestinal recovery following NEC diagnosis individualize when feedings should be safely resumed for each patient.

Fetal Intestinal Cell Growth as a Measure of the Comparative Biofunctionality of Human Milk and Infant Formulas: An In Vitro Study

BACKGROUND

Infant formulas are produced to resemble human milk (HM) and to provide adequate energy and appropriate nutritional components for suitability of infant growth and development, some of which are customized for specific medical conditions. However, it has remained unclear whether formulas contain any biofunctionality equivalent to HM, particularly fetal intestinal cell growth promotion.

OBJECTIVE

To evaluate the biofunctionality in HM and various formulas by using an in vitro fetal intestinal cell growth assay.

MATERIALS AND METHODS

Nine specimens of HM collected from 9 milk donors and 16 formulas consisting of 5 regular formulas (RFs), 2 preterm formulas (PFs), 2 partial hydrolysate formulas (PHFs), 3 extensive hydrolysate formulas (EHFs), 2 amino acid formulas (AAFs), and 2 soy protein formulas (SPFs) were included. Fetal intestinal cell growth assay was performed in six replicates per milk specimen. Biofunctionality of HM digest (HMD) derived from in vitro tryptic digestion of HM was also examined. Statistical analysis was performed by ANOVA with post-hoc Tukey's Honestly Significant Difference test.

RESULTS

The fetal intestinal cell growth-promoting activity of HM and formula groups were sorted from the highest as follows: HM, 192.8% ± 16.7%; AAF, 153.5% ± 17.8%; EHF, 149.4% ± 12.5%; RF, 123.5% ± 14.2%; PHF, 111.2% ± 17.9%; PF, 110.3% ± 8.2%; and SPF, 109.3% ± 17.3%. Statistical analysis showed that growth promotion of HM was significantly higher than that of all examined formulas (p < 0.0001). Among formulas, EHF and AAF showed greater growth-promoting activity than the others (p < 0.0001). HM and HMD had a comparable growth-promoting effect on fetal intestinal cells (198.5% ± 27.9% versus 191.2% ± 17.9%, p = 0.724), supporting the potential impact of HM biofunctionality under physiologic gastrointestinal digestion.

CONCLUSIONS

Our data suggested that formulas are not equivalent to HM in respect of fetal intestinal cell growth biofunctionality. Despite having less activity than HM, EHF and AAF exhibited considerable levels of growth-promoting effect that may have clinical implications, especially when HM is unavailable.

Nutrition Management of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is one of the most significant causes of morbidity and mortality among premature infants. The exact cause is considered multifactorial and related to gastrointestinal immaturity, inflammation and enteral feeding. The role of nutrition is vitally important in NEC. The main modifiable risk factor is the introduction and advancement of enteral feedings. After an infant has recovered from NEC, enteral feeds should be cautiously resumed to prevent injury from prolonged use of parenteral nutrition. The logistics of how, when, and what to feed are somewhat unclear and often depend on the severity of the disease. For patients with an enterostomy, refeeding the distal intestine with the small-intestinal ostomy output may improve bowel growth and prevent long-term complications.

Necrotizing enterocolitis in the setting of milk allergy after pediatric living donor liver transplantation

NEC is an idiopathic intestinal mucosal injury that may progress to transmural bowel necrosis without mesenteric ischemia. NEC usually affects 7- to 10-day-old neonates following enteral feeding. A 10-month-old girl with no history of laparotomy underwent LDLT for acute liver failure. After starting enteral feeding on postoperative day 5, she developed abdominal distention. Diffuse PVG and PI were detected by radiologic modalities. Exploratory laparotomy revealed patchy necrosis of the intestine without perforation. The microscopic findings of a resected specimen revealed transmural coagulative necrosis with multiple small thromboses compatible with neonatal NEC features, and eosinophil infiltration was also observed. Subsequently, after the resumption of enteral feeding with cow's milk, she developed severe diarrhea, the symptoms of which were eliminated after the administration of cow's milk was stopped. These clinical and pathological findings support the speculation that NEC might have been induced by a CMA. Food allergies, which can be induced by immunosuppressive agents, should be considered as a potential cause of NEC in the setting of pediatric liver transplantation.

Use of extensively hydrolysed formula for refeeding neonates postnecrotising enterocolitis: a nationwide survey-based, cross-sectional study

OBJECTIVE

To evaluate the prevalence of and reasons for using extensively hydrolysed formulas (EHFs) of cow's milk proteins in the French neonatal units as well as the modality of their prescription for refeeding infants recovering from necrotising enterocolitis (NEC).

METHODS

A multicentre nationwide cross-sectional study using a questionnaire to address the prevalence of use and the reasons for prescribing EHF in hospitalised neonates and to examine the protocols and the actual reasons for their use for refeeding infants in recovery from NEC. The questionnaire was sent to only 1 senior neonatologist in each neonatal unit included in the study.

RESULTS

More than half of the French neonatal units participated in the survey. 91% of the surveyed units used EHF. Of 1969 infants hospitalised on the day the survey was run, 12% were fed on an EHF. 11% of the EHF prescriptions were due to previous NEC. The main reasons for using an EHF to feed infants post-NEC were the absence of human milk (75%) and surgical management of NEC (17%). When given, EHF was mainly prescribed for a period varying between 15 days and 3 months. None of the involved units continued using the EHF after 6 months of age. More than half of the surveyed units acknowledged hospitalising infants for the initiation of weaning EHF but only 21% of them tested these infants for cow's milk allergy.

CONCLUSIONS

The prevalence of EHF use in the French neonatal units is high. Refeeding infants post-NEC is one of the main reasons for such a high prevalence. The main incentive for using an EHF is the absence of human breast milk, either maternal or donor.

Comprehensive evaluation of 11 cytokines in premature infants with surgical necrotizing enterocolitis

OBJECTIVE

A prospective study to investigate the pattern of pro- and anti-inflammatory cytokine responses in neonates with surgical necrotizing enterocolitis (NEC) and identify those cytokines being the most promising for future research.

METHODS

A panel of 11 different cytokines were measured in 9 infants with proven NEC and compared with 18 age-matched healthy neonates.

RESULTS

The serum concentrations of the interleukins (IL)-6, IL-8, and IL-10 were significantly (32-fold to 56-fold) higher in NEC infants compared with controls. In contrast, IL-5, IFN gamma, IL-4 and IL-2 showed slightly (1.4-fold to 5.9-fold) lower levels in the NEC samples. However, these cytokines showed a very low absolute concentration in infants with NEC and in controls. The sum of the serum concentrations of IL-6, IL-8 and IL-10 was able to clearly separate infants with NEC from control samples. IL-1 beta and TNF-alpha showed no statistically different levels. The serum levels of TNF-beta and IL-12p70 were below the detection limit in more than 50% of all samples per group.

CONCLUSION

In spite of strong local inflammation only three out of eleven cytokines (IL-6, IL-8, and IL-10) showed strongly increased serum levels indicating an important role of them in the pathogenesis of NEC. At least two of these three cytokines were elevated in every single NEC patient. Thus, longitudinal monitoring of combined IL-8, IL-6, and IL-10 levels could reveal their potency in being clinical relevant markers in NEC.

Evolution of in vitro cow's milk protein-specific inflammatory and regulatory cytokine responses in preterm infants with necrotising enterocolitis

BACKGROUND

We have previously reported evidence of in vitro sensitisation to cow's milk protein in peripheral blood mononuclear cells (PBMCs) in preterm infants with necrotising enterocolitis (NEC). In the present study, we document the changes in the PBMC responses to stimulation with mitogen (phytohaemagglutinin) and cow's milk proteins β-lactoglobulin (β-lg) and casein over time: from the acute presentation of NEC, to initial recovery (reinitiation of enteral feeds), to full recovery (full feeding).

METHODS

Of the 14 preterm infants recruited with acute NEC, 12 were followed until fully enterally fed (2 died during the acute phase). Cytokine secretion (interferon-γ [IFN-γ], interleukin 4, [IL-4], IL-10, and transforming growth factor-β1 [TGF-β1]) by PBMCs in response to stimulation by phytohaemagglutinin, β-lg, and casein was measured by enzyme-linked immunospot in the acute phase and subsequently at recovery and full recovery.

RESULTS

The high levels of cytokine secretion (IFN-γ, IL-4, IL-10, and TGF-β1) observed in response to β-lg and casein in the acute phase increased by a further 50% to 100% at recovery (P < 0.005). At full recovery (full feeding), however, IFN-γ, IL-4, and IL-10 secretion response had returned to, or below, acute-phase levels, whereas the augmented TGF-β1 response was maintained (P = 0.005 vs acute level). This response pattern was similar for casein, and did not appear to be influenced by the nature of the feed used following NEC (breast milk/formula/hydrolysed formula).

CONCLUSIONS

The evolution of the cytokine response profile in parallel with the clinical recovery from NEC is consistent with a putative role for TGF-β1 in regulation of inflammation, and possibly also oral tolerance.

Late type of bronchial response to milk ingestion challenge: a comparison of open and double-blind challenge

Background. In some asthmatics the food allergy, for example, to milk, can participate in their bronchial complaints. The role of food allergy should be confirmed definitively by food ingestion challenge performed by an open challenge with natural foods (OFICH) or by a double-blind placebo-controlled food challenge (DBPCFC). Objectives. To investigate the diagnostic value of these techniques for confirmation of a suspected milk allergy in bronchial asthma patients. Methods. In 54 asthmatics with a positive history and/or positive skin tests for milk the 54 OFICH, and DBPCFC, were performed in combination with spirometry. Results. The 54 patients developed 39 positive late asthmatic responses (LAR) and 15 negative asthmatic responses to OFICH and 40 positive LARs and 14 negative responses to DBPCFC. The overall correlation between the OFICH and DBPCFC was statistically significant (P < 0.01). Conclusions. This study has confirmed the existence of LAR to milk ingestion performed by OFICH and DBPCFC in combination with spirometry. The results obtained by both the techniques did not differ significantly. The OFICH with natural food combined with monitoring of objective parameter(s), such as spirometry, seems to be a suitable method for detection of the food allergy in asthmatics. The DBPCFC can be performed as an additional check, if necessary.

An update on necrotizing enterocolitis: pathogenesis and preventive strategies

Necrotizing enterocolitis (NEC) is one of the most critical morbidities in preterm infants. The incidence of NEC is 7% in very-low-birth-weight infants, and its mortality is 15 to 30%. Infants who survive NEC have various complications, such as nosocomial infection, malnutrition, growth failure, bronchopulmonary dysplasia, retinopathy of prematurity, and neurodevelopmental delays. The most important etiology in the pathogenesis of NEC is structural and immunological intestinal immaturity. In preterm infants with immature gastrointestinal tracts, development of NEC may be associated with a variety of factors, such as colonization with pathogenic bacteria, secondary ischemia, genetic polymorphisms conferring NEC susceptibility, anemia with red blood cell transfusion, and sensitization to cow milk proteins. To date, a variety of preventive strategies has been accepted or attempted in clinical practice with regard to the pathogenesis of NEC. These strategies include the use of breast feeding, various feeding strategies, probiotics, prebiotics, glutamine and arginine, and lactoferrin. There is substantial evidence for the efficacy of breast feeding and the use of probiotics in infants with birth weights above 1,000 g, and these strategies are commonly used in clinical practice. Other preventive strategies, however, require further research to establish their effect on NEC.

In vitro cow's milk protein-specific inflammatory and regulatory cytokine responses in preterm infants with necrotizing enterocolitis and sepsis

Enteral feeding with cow's milk formula is associated with neonatal necrotizing enterocolitis (NEC) and sepsis. Dietary antigen sensitization may play a role in promoting and/or sustaining inflammation in both conditions. Aiming at investigating cow's milk protein (CMP)-specific cytokine responses in preterm infants with NEC and sepsis, 14 babies with NEC, 14 matched healthy controls, and 10 septic controls were recruited. Unstimulated and stimulated peripheral blood mononuclear cells (PBMCs) secreting IFN-γ, IL-4, IL-10, and TGF-β1 were counted by the single-cell enzyme-linked immunospot (ELISPOT) assay. During the acute phase of NEC, patients showed a general pattern of a high level of cytokine secretion both when unstimulated and stimulated by mitogen [phytohaemagglutinin (PHA)] and CMPs: beta-lactoglobulin (β-lg) and casein. These responses were more marked to β-lg for IFN-γ, IL-4, and IL-10 than TGF-β1. Cytokine responses in sepsis were lower than in NEC (lowest in healthy controls, with a minimal TGF-β1 response). At term, lower frequencies of cytokine-secreting cells were elicited than during the acute phase, except for TGF-β1 secreting cells, which increased at term (in response to PHA and CMPs) particularly following not only NEC but also sepsis.

Changes in intestinal Toll-like receptors and cytokines precede histological injury in a rat model of necrotizing enterocolitis

It is unclear whether the broad inflammatory response shown in neonatal necrotizing enterocolitis (NEC) is the cause or the effect of tissue injury. Toll-like receptors (TLRs) on intestinal dendritic, mononuclear, and epithelial cells recognize bacterial ligands and damaged tissues, thus activating the inflammatory response. The present study aimed to determine whether active TLR signaling would precede histological injury in NEC. Newborn rat pups were divided into four groups: dam fed, dam fed-hypoxic, formula fed, and formula fed-hypoxic (NEC). The ileal tissues were evaluated for NEC scores at 24, 48, 72, and 120 h. Quantitative real-time reverse transcription-polymerase chain reaction and immunohistochemistry were used to measure and localize intestinal TLRs. Cytokines were assessed by a multispot cytokine array. Among the four groups, ileal injury was seen only after 72 h of formula feeding and hypoxia. We found selective induction of mRNA levels in NEC compared with dam-fed controls for TLR2 > TLR4 > TLR1 = TLR3, TLR7, and TLR9 > TLR6 (P < 0.01); TLR5 was downregulated (P < 0.01). All TLR changes started at 48 h, before any histological evidence of NEC. Both Th1-type cytokines (IFN-gamma, IL-1beta, TNF-alpha, and KC/GRO) and Th2-type cytokines (IL-4, IL-5 and IL-13) were significantly increased in NEC but also in nondamaged formula-fed rat ileum. In conclusion, the intestinal expression of TLRs and cytokines precedes histological injury in the experimental NEC.