The Protective Influence of Chondroitin Sulfate, a Component of Human Milk, on Intestinal Bacterial Invasion and Translocation

Effect of Oral Chondroitin Sulfate Supplementation on Acute Brain Injury in a Murine Necrotizing Enterocolitis Model

BACKGROUND

Necrotizing enterocolitis (NEC) is a devastating condition where inflammatory changes and necrosis in the gut results in activation of brain microglia and subsequent neurodevelopmental impairment. Chondroitin sulfate (CS) is a glycosaminoglycan in human breast milk that is absent in conventional formulas. We hypothesized that oral formula supplementation with CS during a murine model of experimental NEC would not only attenuate intestinal injury, but also brain injury.

STUDY DESIGN

NEC was induced in mouse pups on postnatal days (PNDs) 5 to 8. Three conditions were studied: (1) breastfed controls, (2) NEC, and (3) NEC+enteral CS (formula+200 mg/kg/d of CS). Pups were euthanized on PND 9 or reunited with dams by the evening of PND 8. Intestinal segments were H&E stained, and immunohistochemistry was performed on brain tissue for Iba-1 to assess for microglial morphology and cortical changes. Neurodevelopmental assays were performed on mice reunited with foster dams on PND 9. Single-cell RNA-sequencing analysis was performed on human intestinal epithelial cells exposed to (1) nothing, (2) hydrogen peroxide (H 2 O 2 ) alone, or (3) H 2 O 2 + CS to look at the differential gene expression between groups. Groups were compared with ANOVA or Kruskal-Wallis tests as appropriate with p < 0.05 considered significant.

RESULTS

Compared with NEC, mice treated with oral CS showed improved clinical outcomes, decreased intestinal injury, and attenuated microglial activation and deleterious cortical change. Mice with CS performed better on early neurodevelopmental assays when compared with NEC alone. Single-cell analysis of HIEC-6 cells demonstrated that CS treatment down regulated several inflammatory pathways including nuclear factor κB-suggesting an explanation for the improved Th17 intestinal cytokine profile.

CONCLUSIONS

Oral CS supplementation improved both physiological, clinical, and developmental outcomes. These data suggest that CS is a safe compound for formula supplementation for the prevention of NEC.

Gastroprotective Effects of Oral Glycosaminoglycans with Sodium Alginate in an Indomethacin-Induced Gastric Injury Model in Rats

The gastrointestinal (GI) mucosal barrier is often exposed to inflammatory and erosive insults, resulting in gastric lesions. Glycosaminoglycans (GAGs), such as hyaluronic acid (HA), chondroitin sulfate (CS), and N-acetylglucosamine (NAG) have shown potential beneficial effects as GI protectants. This study aimed to evaluate the gastroprotective effects of oral GAGs in rats with indomethacin-induced GI lesions. Forty-five Sprague-Dawley rats (8-9 weeks-old, 228 ± 7 g) were included in the study, divided into five study groups, and given, administered orally, either sucralfate (positive control group; PC), NAG (G group), sodium alginate plus HA and CS (AHC group), sodium alginate plus HA, CS, and NAG (AHCG group), or no treatment (negative control group; NC). Animals were administered 12.5 mg/kg indomethacin orally 15 min after receiving the assigned treatment. After 4 h, stomach samples were obtained and used to perform a macroscopic evaluation of gastric lesions and to allow histological assessment of the gastric wall (via H/E staining) and mucous (via PAS staining). The AHCG group showed significant gastroprotective improvements compared to the NC group, and a similar efficacy to the PC group. This combination of sodium alginate with GAGs might, therefore, become a safe and effective alternative to prescription drugs for gastric lesions, such as sucralfate, and have potential usefulness in companion animals.

Chondroitin sulfate supplementation improves clinical outcomes in a murine model of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) continues to be a devastating disease in preterm neonates and has a paucity of medical management options. Chondroitin sulfate (CS) is a naturally occurring glycosaminoglycan (GAG) in human breast milk (HM) and has been shown to reduce inflammation. We hypothesized that supplementation with CS in an experimental NEC model would alter microbial diversity, favorably alter the cytokine profile, and (like other sulfur compounds) improve outcomes in experimental NEC via the eNOS pathway. NEC was induced in 5-day-old pups. Six groups were studied (n = 9-15/group): (1) WT breastfed and (2) Formula fed controls, (3) WT NEC, (4) WT NEC + CS, (5) eNOS KO (knockout) NEC, and (6) eNOS KO NEC + CS. Pups were monitored for clinical sickness score and weights. On postnatal day 9, the pups were killed. Stool was collected from rectum and microbiome analysis was done with 16 s rRNA sequencing. Intestinal segments were examined histologically using a well-established injury scoring system and segments were homogenized and analyzed for cytokine profile. Data were analyzed using GraphPad Prism with p < 0.05 considered significant. CS supplementation in formula improved experimental NEC outcomes when compared to NEC alone. CS supplementation resulted in similar improvement in NEC in both the WT and eNOS KO mice. CS supplementation did not result in microbial changes when compared to NEC alone. Our data suggest that although CS supplementation improved outcomes in NEC, this protection is not conferred via the eNOS pathway or alteration of microbial diversity. CS therapy in NEC does improve the intestinal cytokine profile and further experiments will explore the mechanistic role of CS in altering immune pathways in this disease.

Impact of neonatal nutrition on necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the leading cause of morbidity and mortality in preterm infants. NEC is multifactorial and the result of a complex interaction of feeding, dysbiosis, and exaggerated inflammatory response. Feeding practices in the neonatal intensive care units (NICUs) can vary among institutions and have significant impact on the vulnerable gastointestinal tract of preterm infants. . These practices encompass factors such as the type of feeding and fortification, duration of feeding, and rate of advancement, among others. The purpose of this article is to review the data on some of the most common feeding practices in the NICU and their impact on the development of NEC in preterm infants. Data on the human milk bioactive component glycosaminoglycans, specifically hyaluronan, will also be discussed in the context of postnatal intestinal development and NEC prevention.

Oral Application of Mother's Own Milk for Reducing Necrotizing Enterocolitis in Preterm Infants: An Updated Meta-Analysis of RCTs

Background

Necrotizing enterocolitis (NEC) and late-onset sepsis (LOS) are the major contributors to mortality and morbidity in preterm infants. This updated meta-analysis was aimed to assess the effects of mother's milk on the incidence of NEC, LOS, and other clinical outcomes in preterm infants.

Methods

PubMed, Embase, and the Cochrane library were searched for papers published up to October 2022.

Results

A total of 13 RCTs with 1330 infants were included in the final analysis. Significant difference in NEC (stage 2 or 3) was found between the intervention group and the control group (RR = 0.508, 95% CI: 0.314-0.822, and P=0.008). The incidence of proven LOS (RR = 0.809, 95% CI: 0.610-1.071, and P=0.139) and death (RR = 0.800, 95% CI: 0.571-1.122, and P=0.196) was comparable between the two groups. Statistical differences in the incidence of proven or probable LOS (RR = 0.705, 95% CI: 0.577-0.862, and P=0.001) and length of hospitalization (WMD = -4.868, 95% CI: -6.608 to -3.128, and P < 0.001) between the intervention group and the control group were observed.

Conclusions

The results of this updated meta-analysis showed that compared to the placebo, mother's milk provides better effects in reducing the incidences of NEC, proven or probable LOS, and the length of stay, whereas no significant benefit of mother's milk was observed in reducing the incidence of proven LOS and death.

The Endothelial Glycocalyx and Neonatal Sepsis

Sepsis carries a substantial risk of morbidity and mortality in newborns, especially preterm-born neonates. Endothelial glycocalyx (eGC) is a carbohydrate-rich layer lining the vascular endothelium, with important vascular barrier function and cell adhesion properties, serving also as a mechano-sensor for blood flow. eGC shedding is recognized as a fundamental pathophysiological process generating microvascular dysfunction, which in turn contributes to multiple organ failure and death in sepsis. Although the disruption of eGC and its consequences have been investigated intensively in the adult population, its composition, development, and potential mechanisms of action are still poorly studied during the neonatal period, and more specifically, in neonatal sepsis. Further knowledge on this topic may provide a better understanding of the molecular mechanisms that guide the sepsis pathology during the neonatal period, and would increase the usefulness of endothelial glycocalyx dysfunction as a diagnostic and prognostic biomarker. We reviewed several components of the eGC that help to deeply understand the mechanisms involved in the eGC disruption during the neonatal period. In addition, we evaluated the potential of eGC components as biomarkers and future targets to develop therapeutic strategies for neonatal sepsis.

It's all in the milk: chondroitin sulfate as potential preventative therapy for necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a devastating condition affecting up to 5% of neonatal intensive care unit (NICU) admissions. Risk factors include preterm delivery, low birth weight, and antibiotic use. The pathogenesis is characterized by a combination of intestinal ischemia, necrosis of the bowel, reperfusion injury, and sepsis typically resulting in surgical resection of afflicted bowel. Targeted medical therapy remains elusive. Chondroitin sulfate (CS) holds the potential to prevent the onset of NEC through its anti-inflammatory properties and protective effect on the gut microbiome. The purpose of this review is to outline the many properties of CS to highlight its potential use in high-risk infants and attenuate the severity of NEC. The purpose of this review is to (1) discuss the interaction of CS with the infant microbiome, (2) review the anti-inflammatory properties of CS, and (3) postulate on the potential role of CS in preventing NEC. IMPACT: NEC is a costly medical burden in the United States. Breast milk is the best preventative measure for NEC, but not all infants in the NICU have access to breast milk. Novel therapies and diagnostic tools are needed for NEC. CS may be a potential therapy for NEC due to its potent anti-inflammatory properties. CS could be added to the formula in an attempt to mitigate breast milk disparities.

Antiviral Properties of Human Milk

Humans have always coexisted with viruses, with both positive and negative consequences. Evolutionary pressure on mammals has selected intrinsic properties of lactation and milk to support the relatively immunocompromised neonate from environmental pathogens, as well as support the normal development of diverse immune responses. Human milk supports both adaptive and innate immunity, with specific constituents that drive immune learning and maturation, and direct protection against microorganisms. Viruses constitute one of the most ancient pressures on human evolution, and yet there is a lack of awareness by both public and healthcare professionals of the complexity of human milk as an adaptive response beyond the production of maternal antibodies. This review identifies and describes the specific antiviral properties of human milk and describes how maternal support of infants through lactation is protective beyond antibodies.

Hyaluronan 35 kDa enhances epithelial barrier function and protects against the development of murine necrotizing enterocolitis

BACKGROUND

Disruption of tight junctions (TJs) predisposes to bacterial translocation, intestinal inflammation, and necrotizing enterocolitis (NEC). Previously, studies showed that hyaluronan (HA), a glycosaminoglycan in human milk, maintains intestinal permeability, enhances intestinal immunity, and reduces intestinal infections. In this study, we investigated the effects of HA 35 kDa on a NEC-like murine model.

METHODS

Pups were divided into Sham, NEC, NEC+HA 35, and HA 35. Severity of intestinal injury was compared using a modified macroscopic gut scoring and histologic injury grading. The effect of HA 35 on intestinal permeability was determined by measuring FITC dextran and bacterial translocation. RNA and protein expression of TJ proteins (claudin-2, -3, -4, occludin, and ZO-1) were compared between the groups.

RESULTS

Pups in the NEC+HA 35 group had increased survival and lower intestinal injury compared to untreated NEC. In addition, HA 35 reduced intestinal permeability, bacterial translocation, and proinflammatory cytokine release. Ileal expression of claudin-2, -3, -4, occludin, and ZO-1 was upregulated in NEC+HA 35 and HA 35 compared to untreated NEC and shams.

CONCLUSION

These findings suggest that HA 35 protects against NEC partly by upregulating intestinal TJs and enhancing intestinal barrier function.

The Role of Glycosaminoglycans in Protection from Neonatal Necrotizing Enterocolitis: A Narrative Review

Necrotizing enterocolitis, a potentially fatal intestinal inflammatory disorder affecting primarily premature infants, is a significant cause of morbidity and mortality in neonates. While the etiology of the disease is, as yet, unknown, a number of risk factors for the development of necrotizing enterocolitis have been identified. One such risk factor, formula feeding, has been shown to contribute to both increased incidence and severity of the disease. The protective influences afforded by breastfeeding are likely attributable to the unique composition of human milk, an extremely potent, biologically active fluid. This review brings together knowledge on the pathogenesis of necrotizing enterocolitis and current thinking on the instrumental role of one of the more prominent classes of bioactive components in human breast milk, glycosaminoglycans.

Effects of oropharyngeal administration of colostrum on the incidence of necrotizing enterocolitis, late-onset sepsis, and death in preterm infants: a meta-analysis of RCTs

Necrotizing enterocolitis (NEC) and late-onset sepsis (LOS) are two major contributors to death among preterm infants. Oropharyngeal administration of colostrum (OAC) has been proved as an easy, safe, and economically viable technique to help preterm neonates to build up their immunity. In this review, we assessed the effects of OAC on preterm infants. Several mainstream databases were searched including PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), and a website of clinical trials. Randomized controlled trials (RCTs) comparing OAC vs. placebo or no intervention in preterm infants (gestation age <34 weeks or birth weight <1500 g) were eligible. Overall, nine RCTs (n = 689) were included in the review. Meta-analysis showed no statistical significance in terms of the incidence of NEC (RR = 0.59, 95% CI = 0.33-1.06, p = 0.08), LOS (RR = 0.78, 95% CI = 0.60-1.03, p = 0.08) and mortality rate (RR = 0.63, 95% CI = 0.38-1.05, p = 0.07). No significant difference was found in the subgroup analysis, apart from the group of the undeveloped region in NEC and mortality. In addition, time was significantly reduced in terms of achieving full enteral feeding (MD = -3.60, 95% CI = -6.55-0.64, p = 0.02) and hospital stay (MD = -10.38, 95% CI = -18.47-2.29, p = 0.01). The results show that OAC does not reduce the incidences of NEC, LOS, and death in preterm infants, but there is a trend toward a positive effect. It is therefore recommended as routine care for preterm infants in the NICU.

Antibacterial Activity and Cytotoxicity of Immobilized Glucosamine/Chondroitin Sulfate on Polylactic Acid Films

Polylactic acid (PLA) is one of the most produced polymeric materials, due to its exceptional chemical and mechanical properties. Some of them, such as biodegradability and biocompatibility, make them attractive for biomedical applications. Conversely, the major drawback of PLA in the biomedical field is their vulnerability to bacterial contamination. This study focuses on the immobilization of saccharides onto the PLA surface by a multistep approach, with the aim of providing antibacterial features and evaluting the synergistic effect of these saccharides. In this approach, after poly (acrylic acid) (PAA) brushes attached non-covalently to the PLA surface via plasma post-irradiation grafting technique, immobilization of glucosamine (GlcN) and chondroitin sulfate (ChS) to the PAA brushes was carried out. To understand the changes in surface properties, such as chemical composition, surface topography and hydrophilicity, the untreated and treated PLA films were analyzed using various characterization techniques (contact angle, scanning electron microscopy, X-ray photoelectron spectroscopy). In vitro cytotoxicity assays were investigated by the methyl tetrazolium test. The antibacterial activity of the PLA samples was tested against Escherichia coli and Staphylococcus aureus bacteria strains. Plasma-treated films immobilized with ChS and GlcN, separately and in combination, demonstrated bactericidal effect against the both bacteria strains and also the results revealed that the combination has no synergistic effect on antibacterial action.