Pediatric Intestinal Failure-Associated Liver Disease: Challenges in Identifying Clinically Relevant Biomarkers

The Power of Networking and Lessons Learned From Omegaven

As more meetings become virtual, the impact of "live" meetings is being reevaluated. Here one example of how a chance meeting at a national pharmacy meeting led to the development of a new drug therapy that reinvented how parenteral nutrition is provided to infants and children is described. Along the way, many lessons were learned both in the lab and at home. Addressing the challenges raised by others, understanding how the FDA works, and the power of parental involvement are all considered. Until 2013, the only FDA-approved lipid emulsions were those composed of pure soybean oils. Starting with compassionate use protocol in 2004, it took 18 years and hundreds of patients to bring a pure fish oil lipid emulsion to the US market. First used off label to treat a soy-allergic patient dependent on parenteral nutrition, researchers at Boston Children's Hospital later conducted animal studies on its role in treating and preventing intestinal failure associated with liver injury and later translated it into clinical trials that led to the drug's approval in 2018. This is a recount of those efforts.

MicroRNA 122 Reflects Liver Injury in Children with Intestinal Failure-Associated Liver Disease Treated with Intravenous Fish Oil

BACKGROUND

There is evidence that microRNA (MIR) 122 is a biomarker for various liver diseases in adults and children. To date, MIR122 has not been explored in children with intestinal failure-associated liver disease (IFALD, or hyperbilirubinemia associated with prolonged parenteral nutrition).

OBJECTIVES

This study's purpose was to investigate changes in plasma miR-122, correlate miR-122 with serum liver function tests and enzymes, and investigate changes in whole blood transcripts including miR-122 targets in a group of children with IFALD who received pure intravenous fish oil (FO) as a treatment for cholestasis.

METHODS

This was a prospective, observational study that enrolled children with IFALD who received intravenous FO (1 g/kg/d) and whose cholestasis resolved with FO. Plasma miR-122 was measured using reverse transcription-quantitative real-time PCR, and whole blood miR-122 targets were quantified using RNA sequencing.

RESULTS

Fourteen subjects with median age 6 mo (IQR: 3-65 mo) were enrolled. RNA sequence data were available for 4 subjects. When compared with the start of FO, median miR-122 concentrations at 6 mo of FO therapy decreased [1.0 (IQR: 1.0-1.0) compared with 0.04 (IQR: 0.01-0.6), P = 0.009]. At the start of FO, miR-122 correlated with conjugated bilirubin (r = 0.56; P = 0.038). At ∼3 mo of FO, miR-122 correlated with conjugated bilirubin (r = 0.56; P = 0.045). Reactive oxygen species, heme metabolism, coagulation, adipogenesis, IL-6-Janus kinase-signal transducer and activator of transcription (JAK-STAT) 3, IL-2-STAT5, transforming growth factor-β, TNF-α, inflammatory response, mammalian target of rapamycin gene families (normalized enrichment scores < -1.4), and miR-122 target genes were significantly downregulated with FO.

CONCLUSIONS

In this small cohort of young children with IFALD, miR-122 decreased with FO therapy and correlated with conjugated bilirubin. Key pathways involving oxidation, inflammation, cellular differentiation, and nutrient regulation were downregulated. Data from this study provide information about IFALD and FO. This trial was registered at www.clinicaltrials.gov as NCT00969332.

Copper Deficiency in Children With Intestinal Failure: Risk Factors and Influence on Hematological Cytopenias

BACKGROUND

We investigated to what extent serum copper influences hemoglobin (Hb), neutrophil, and platelet counts and the factors associated with serum copper in children with intestinal failure (IF) who have their micronutrient status monitored according to a standard protocol.

METHODS

Children with IF admitted to a pediatric intestinal rehabilitation program and receiving home parenteral nutrition (PN) were followed up prospectively. Patients received vitamins and multi-trace elements (TEs) as part of the PN. Copper, iron, zinc, vitamin A, and cobalamin serum levels were routinely monitored at 3-month intervals or monthly when a deficiency was detected. Complete blood counts were performed biweekly. Repeated-measures analyses were used to estimate the effect of explanatory variables on the outcomes.

RESULTS

Thirteen children with a median time receiving PN of 16.6 months were included. An average of 7 copper measurements per patient were performed; 53.8% of patients had a low serum level at least twice during the follow-up. Eight patients with cholestasis had TEs of PN discontinued. In the multivariable analysis, copper was not associated with Hb levels; an increase of 10 µg/dL in serum copper resulted in an increase of 240/mm³ (95% confidence interval [CI], 18.0-30.1) neutrophils and of 8429/mm³ (95% CI, 466-1219) platelets (P < .001). Time of PN without copper, direct bilirubin levels, and ostomy were associated with lower serum copper.

CONCLUSION

The increase in serum copper was associated with significant increases in neutrophil and platelet counts. Time without copper in PN, cholestasis, and having an ostomy negatively influenced copper status.

Combination of Diet Quality Score, Plasma Carotenoids, and Lipid Peroxidation to Monitor Oxidative Stress

It is important to understand the association between oxidative stress-related parameters and to evaluate their status in advance of chronic disease development. Further development towards disease can then be prevented by dietary antioxidants. The present study was aimed at assessing the relationship between diet quality, blood antioxidants, and oxidative damage to determine whether the association between these markers differs by oxidative stress status. For a cross-sectional analysis, we used data and samples of baseline information from a prospective cohort study. A total of 1229 eligible adults were classified into apparently healthy subjects (66.5%) and those with oxidative stress conditions (35.5%). Diet quality was assessed using the recommended food score (RFS). Plasma carotenoids (blood antioxidants) and blood/urinary malondialdehyde (MDA; oxidative damage) were determined by high-performance liquid chromatography. We found that the healthy group was younger, and they had a lower RFS and plasma MDA level and higher plasma carotenoids compared to the oxidative stress condition group. This result is probably due to the quenching of the oxidative response in the tissues of those people. A positive association of RFS with plasma carotenoids (total and β-carotene) was found in both groups, suggesting that carotenoids are a robust reflection of diet quality. Negative associations were observed between plasma MDA and RFS in the oxidative stress condition group and between urinary MDA and plasma zeaxanthin in the healthy group. Erythrocyte MDA was positively associated with plasma carotenoids (total, lutein, zeaxanthin, β-cryptoxanthin, and α- and β-carotene), regardless of health condition, probably also as a result of the use of carotenoids as antioxidants. In conclusion, these results indicate that the above three factors may be associated with the oxidative stress response and depend on the oxidative status. Furthermore, it was also suggested that erythrocytes are important in the oxidative stress response and the quenching of this response is represented in plasma carotenoids.

Administration of antibiotics contributes to cholestasis in pediatric patients with intestinal failure via the alteration of FXR signaling

The link between antibiotic treatment and IF-associated liver disease (IFALD) is unclear. Here, we study the effect of antibiotic treatment on bile acid (BA) metabolism and investigate the involved mechanisms. The results showed that pediatric IF patients with cholestasis had a significantly lower abundance of BA-biotransforming bacteria than patients without cholestasis. In addition, the BA composition was altered in the serum, feces, and liver of pediatric IF patients with cholestasis, as reflected by the increased proportion of primary BAs. In the ileum, farnesoid X receptor (FXR) expression was reduced in patients with cholestasis. Correspondingly, the serum FGF19 levels decreased significantly in patients with cholestasis. In the liver, the expression of the rate-limiting enzyme in bile salt synthesis, cytochrome P450 7a1 (CYP7A1), increased noticeably in IF patients with cholestasis. In mice, we showed that oral antibiotics (gentamicin, GM or vancomycin, VCM) reduced colonic microbial diversity, with a decrease in both Gram-negative bacteria (GM affected Eubacterium and Bacteroides) and Gram-positive bacteria (VCM affected Clostridium, Bifidobacterium and Lactobacillus). Concomitantly, treatment with GM or VCM decreased secondary BAs in the colonic contents, with a simultaneous increase in primary BAs in plasma. Moreover, the changes in the colonic BA profile especially that of tauro-beta-muricholic acid (TβMCA), were predominantly associated with the inhibition of the FXR and further altered BA synthesis and transport. In conclusion, the administration of antibiotics significantly decreased the intestinal microbiota diversity and subsequently altered the BA composition. The alterations in BA composition contributed to cholestasis in IF patients by regulating FXR signaling.

Using antibiotics during intestinal failure in children may lead to the development of liver disease. Microbiota in the gut play vital roles in balancing the digestive system, including transforming bile acids (BAs) secreted by the liver into forms that help us digest food. Wai Cai and Ying Wang at Shanghai Jiao Tong University in China and co-workers examined samples from 46 children treated with antibiotics for intestinal failure. The patients who also had cholestasis – disrupted production and flow of bile – had far fewer BA-transforming bacteria in their gut than those without cholestasis. They also had altered expression of a crucial BA receptor protein. Experiments on mice showed that treatment with two different antibiotics reduced microbiota diversity, which in turn influenced BA receptor signaling and altered BA composition, contributing to cholestasis.