Mechanisms of disease: update on the molecular etiology and fundamentals of parenteral nutrition associated cholestasis

Intraduodenal fecal microbiota transplantation ameliorates gut atrophy and cholestasis in a novel parenteral nutrition piglet model

Total parenteral nutrition (TPN) provides lifesaving nutritional support intravenously; however, it is associated with significant side effects. Given gut microbial alterations noted with TPN, we hypothesized that transferring fecal microbiota from healthy controls would restore gut-systemic signaling in TPN and mitigate injury. Using our novel ambulatory model (US Patent: US 63/136,165), 31 piglets were randomly allocated to enteral nutrition (EN), TPN only, TPN + antibiotics (TPN-A), or TPN + intraduodenal fecal microbiota transplant (TPN + FMT) for 14 days. Gut, liver, and serum were assessed through histology, biochemistry, and qPCR. Stool samples underwent 16 s rRNA sequencing. Permutational multivariate analysis of variance, Jaccard, and Bray-Curtis metrics were performed. Significant bilirubin elevation in TPN and TPN-A versus EN (P < 0.0001) was prevented with FMT. IFN-G, TNF-α, IL-β, IL-8, and lipopolysaccharide (LPS) were significantly higher in TPN (P = 0.009, P = 0.001, P = 0.043, P = 0.011, P < 0.0001), with preservation upon FMT. Significant gut atrophy by villous-to-crypt ratio in TPN (P < 0.0001) and TPN-A (P = 0.0001) versus EN was prevented by FMT (P = 0.426 vs. EN). Microbiota profiles using principal coordinate analysis demonstrated significant FMT and EN overlap, with the largest separation in TPN-A followed by TPN, driven primarily by Firmicutes and Fusobacteria. TPN-altered gut barrier was preserved upon FMT; upregulated cholesterol 7 α-hydroxylase and bile salt export pump in TPN and TPN-A and downregulated fibroblast growth factor receptor 4, EGF, farnesoid X receptor, and Takeda G Protein-coupled Receptor 5 (TGR5) versus EN was prevented by FMT. This study provides novel evidence of prevention of gut atrophy, liver injury, and microbial dysbiosis with intraduodenal FMT, challenging current paradigms into TPN injury mechanisms and underscores the importance of gut microbes as prime targets for therapeutics and drug discovery.NEW & NOTEWORTHY Intraduodenal fecal microbiota transplantation presents a novel strategy to mitigate complications associated with total parenteral nutrition (TPN), highlighting gut microbiota as a prime target for therapeutic and diagnostic approaches. These results from a highly translatable model provide hope for TPN side effect mitigation for thousands of chronically TPN-dependent patients.

Association between SMOF lipid and parenteral nutrition-associated cholestasis compared with Intralipid in extremely low birth weight infants: A retrospective cohort study

BACKGROUND

There is limited evidence on benefits of SMOF lipids (mixed fatty acid emulsion of 30% soybean oil, 30% medium chain triglycerides, 25% olive oil, and 15% fish oil) in reducing parenteral nutrition-associated cholestasis in extremely low birth weight infants, compared with soybean oil-based Intralipid.

AIM

To compare incidence of parenteral nutrition-associated cholestasis in preterm infants who received Intralipid vs SMOF lipid.

METHODS

We conducted a retrospective study on infants with birth weight <1000 g, admitted between January 2013 to December 2022, who received parenteral nutrition for >14 days and divided them into two groups based on lipid emulsion received (Intralipid, n = 187, SMOF, n = 127). Primary outcome was incidence of parenteral nutrition-associated cholestasis, defined as direct bilirubin ≥2 mg/dl.

RESULTS

Baseline characteristics did not differ between the two groups. No significant difference was noted in parenteral nutrition-associated cholestasis between the two groups on logistic regression, (adjusted odds ratio: 0.71, 95% confidence interval 0.35-1.42, P value 0.33) after adjusting for gestational age, parenteral nutrition days, lipid days, and late-onset sepsis.

CONCLUSION

There was no difference in the rates of parenteral nutrition-associated cholestasis between preterm infants administered SMOF lipids and those given Intralipid.

A prognostic model for hepatocellular carcinoma patients based on polyunsaturated fatty acid-related genes

OBJECTIVE

Polyunsaturated fatty acids (PUFAs) have attracted increasing attention for their role in liver cancer development. The objective of this study is to develop a prognosis prediction model for patients with liver cancer based on PUFA-related metabolic gene characteristics.

METHOD

Transcriptome data and clinical data were obtained from public databases, while gene sets related to PUFAs were acquired from the gene set enrichment analysis (GSEA) database. Univariate Cox analysis was conducted on the training set, followed by LASSO logistic regression and multivariate Cox analysis on genes with p < .05. Subsequently, the stepwise Akaike information criterion method was employed to construct the model. The high- and low-risk groups were divided based on the median score, and the model's survival prediction ability, diagnostic efficiency, and risk score distribution of clinical features were validated. The above procedures were also validated in the validation set. Immune infiltration levels were evaluated using four algorithms, and the immunotherapeutic potential of different groups was explored. Significant enrichment pathways among different groups were selected based on the GSEA algorithm, and mutation analyses were conducted. Nomogram prognostic models were constructed by incorporating clinical factors and risk scores using univariate and multivariate Cox regression analysis, validated through calibration curves and clinical decision curves. Additionally, sensitivity analysis of drugs was performed to screen potential targeted drugs.

RESULTS

We constructed a prognostic model comprising eight genes (PLA2G12A, CYP2C8, ABCCI, CD74, CCR7, P2RY4, P2RY6, and YY1). Validation across multiple datasets indicated the model's favorable prognostic prediction ability and diagnostic efficiency, with poorer grading and staging observed in the high-risk group. Variations in mutation status and pathway enrichment were noted among different groups. Incorporating Stage, Grade, T.Stage, and RiskScore into the nomogram prognostic model demonstrated good accuracy and clinical decision benefits. Multiple immune analyses suggested greater benefits from immunotherapy in the low-risk group. We predicted multiple targeted drugs, providing a basis for drug development.

CONCLUSION

Our study's multifactorial prognostic model across multiple datasets demonstrates good applicability, offering a reliable tool for personalized therapy. Immunological and mutation-related analyses provide theoretical foundations for further research. Drug predictions offer important insights for future drug development and treatment strategies. Overall, this study provides comprehensive insights into tumor prognosis assessment and personalized treatment planning.

Systematic review: Methotrexate-A poorly understood and underused medication in inflammatory bowel disease

BACKGROUND

Methotrexate, an immunosuppressant used for the treatment of inflammatory bowel disease (IBD) for over 30 years, remains underused compared to thiopurines.

AIMS

To review the efficacy, safety, optimal dosing and delivery regimens of methotrexate in adults with IBD.

METHODS

We conducted a systematic review of studies involving patients with IBD treated with methotrexate from inception to August 2023. All studies were included from the MEDLINE database via PubMed.

RESULTS

For Crohn's disease, we included eight randomised controlled trials (RCTs) and 17 observational studies. Parenteral methotrexate effectively increased remission rates in steroid-dependent patients at 25 mg/week for 16 weeks and at 15 mg/week for maintenance. Methotrexate can be used in combination with anti-tumour necrosis factor (TNF) agents to reduce immunogenicity. Data comparing thiopurines and methotrexate remain scarce. For ulcerative colitis (UC), we included five RCTs and 10 observational studies were included; there was no evidence to support the use of methotrexate in (UC). We extracted safety data from 17 studies; mild-to-moderate adverse effects were common. The incidence of liver fibrosis or cirrhosis was low.

CONCLUSION

Methotrexate is effective at inducing and maintaining remission in steroid-refractory Crohn's disease and can reduce anti-TNF-induced immunogenicity when used in combination therapy. Data regarding tolerance and safety are reassuring. These findings challenge preconceived ideas on methotrexate and suggest that it is a valid first-line conventional option for the treatment of mild-to-moderate Crohn's disease.

L-Glutamine mitigates bile acid-induced inhibition of growth factor activity in rat hepatocyte cultures

Bile acid-induced hepatotoxicity is inevitable in Cholestasis pathogenesis and L-Glutamine (L-Gln) has been reported to prevent total parenteral nutrition (TPN)-induced cholestasis in premature neonates. While mechanisms remain unknown, we hypothesize that bile acids impair growth factor (GF) function in hepatocytes which L-glutamine prevents through NAPDH oxidase (NOX) modulation. Glycochenodeoxycholic acid (GCDC, 0-100 µM) when added to primary hepatocyte cultures significantly (p < 0.01) decreased the FBS-induced BrdU incorporation, however inhibition of Fibroblast Growth factor (FGF)- or Hepatocyte growth factor (HGF)-induced DNA synthesis was more pronounced (p < 0.001). L-Gln markedly attenuated GCDC-mediated inhibition of DNA synthesis in both FBS and GF-treated cells. GCDC significantly increased the NADPH oxidase activity and NOX-1 protein expression that were markedly reduced by L-Gln and protein kinase c (PKC) inhibitor, LY-333531. Apocynin (APCN) and diphenyliodonium (DPI) significantly blocked the GCDC-mediated inhibition of GF-induced DNA synthesis. This study demonstrates that bile acid-induced hepatotoxicity involves dysfunction of certain growth factors via protein kinase c (PKC)- mediated NOX modulation which can be corrected, at least partly, by L-glutamine.

Prevention of Parenteral Nutrition-associated Cholestasis Using Reduced Dose Soybean Lipid Emulsion: A Multicenter Randomized Trial

INTRODUCTION

Reducing soybean lipid emulsion (SLE) dose may prevent parenteral nutrition-associated cholestasis (PNAC) but effects on growth and neurodevelopment are unknown. The purpose of this study was to evaluate the effect of reduced dose SLE on growth and neurodevelopment.

METHODS

Surgical neonates at 4 centers were randomized to standard SLE (3 g/kg/day) or reduced SLE (1 g/kg/day) over a 12-week period. Bilirubin levels and growth parameters were measured baseline and weekly while on study. The effects of time and group on direct bilirubin and growth were evaluated with a linear mixed effects model. Neurodevelopmental outcomes were assessed at 12- and 24-months corrected gestational age.

RESULTS

Twenty-one individuals were randomized (standard dose = 9, reduced dose = 12). Subjects in the reduced dose group had slower rates of direct bilirubin increase and overall levels decreased earlier than those in the standard dose group. There was a trend toward a faster direct bilirubin decrease in the reduced dose group (p = 0.07 at day 84). There were no differences in the rates of change in weight (p = 0.352 at day 84) or height Z-scores (p = 0.11 at day 84) between groups. One subject in the reduced dose group had abnormal neurodevelopmental testing at 24 months.

CONCLUSIONS

Surgical neonates randomized to a reduced dose of SLE had improved trends in direct bilirubin levels without clinically significant differences in overall growth and neurodevelopment.

TYPE OF STUDY

Randomized Controlled Trial.

LEVEL OF EVIDENCE

II.

Parenteral nutrition-associated liver injury: clinical relevance and mechanistic insights

Intestinal failure-associated liver disease (IFALD) is a relatively common complication in individuals receiving parenteral nutrition (PN). IFALD can be manifested as different types of liver injury, including steatosis, cholestasis, and fibrosis, and could result in liver failure in some cases. The onset and progression of IFALD are highly dependent on various patient and PN-related risk factors. Despite still being under investigation, several mechanisms have been proposed. Liver injury can originate due to caloric overload, nutrient deficiency, and toxicity, as well as phytosterol content, and omega-6 to omega-3 fatty acids ratio contained in lipid emulsions. Additional mechanisms include immature or defective bile acid metabolism, acute heart failure, infections, and sepsis exerting negative effects via Toll-like receptor 4 and nuclear factor κB inflammatory signaling. Furthermore, lack of enteral feeding, gut dysbiosis, and altered enterohepatic circulation that affect the farnesoid x receptor-fibroblast growth factor 19 axis can also contribute to IFALD. Various best practices can be adopted to minimize the risk of developing IFALD, such as prevention and management of central line infections and sepsis, preservation of intestine's length, a switch to oral and enteral feeding, cyclic PN, avoidance of overfeeding and soybean oil-based lipid formulations, and avoiding hepatotoxic substances. The present review thus provides a comprehensive overview of all relevant aspects inherent to IFALD. Further research focused on clinical observations, translational models, and advanced toxicological knowledge frameworks is needed to gain more insight into the molecular pathogenesis of hepatotoxicity, reduce IFALD incidence, and encourage the safe use of PN.

Does inclusion of bioactive n-3 PUFAs in parenteral nutrition benefit postoperative patients undergoing liver surgery? A systematic review and meta-analysis of randomised control trials

OBJECTIVES

This meta-analysis aims to evaluate the effect of n-3 polyunsaturated fatty acids (PUFAs) as a part of parenteral nutrition in patients undergoing liver surgery.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, the Cochrane Central Register of Controlled Trials, Springer link, Web of Science, China National Knowledge Infrastructure and VIP Database.

ELIGIBILITY CRITERIA

We included randomised controlled trials (RCTs) and evaluated the outcomes of liver function, inflammatory reaction, the influence of certain markers of the immune system, and specific clinical indexes for patients undergoing liver surgery and receiving parenteral nutrition with n-3 PUFAs.

DATA EXTRACTION AND SYNTHESIS

The Cochrane Collaboration's tool was used to assess the risk of bias for each study. Findings were summarised in Grades of Recommendation, Assessment, Development and Evaluation evidence profiles and synthesised qualitatively.

RESULTS

Eight RCTs, including 748 patients (trial: 374; control: 374), were included in the meta-analysis. Compared with patients in the control group, the patients in the n-3 PUFA group who underwent liver surgery had significantly lower aspartate aminotransferase (mean difference, MD -42.72 (95% CI -71.91 to -13.52); p=0.004), alanine aminotransferase (MD -38.90 (95% CI -65.44 to -12.37); p=0.004), white cell count (MD -0.93 (95% CI -1.60 to -0.26); p=0.007) and IL-6 (MD -11.37 (95% CI -14.62 to -8.13); p<0.00001) levels and a higher albumin level (MD 0.42 (95% CI 0.26 to 0.57); p<0.00001). They also had fewer infection complications (OR 0.44 (95% CI 0.28 to 0.68); p=0.0003) and a shorter duration of hospital stay (MD -2.17 (95% CI -3.04 to -1.3); p<0.00001) than the controls. However, there were no significant differences in terms of total bilirubin, TNF-α, IL-2, IgA, IgG, IgM and CD3, biliary leakage and mortality between the two groups.

CONCLUSIONS

We found that n-3 PUFAs can benefit patients undergoing liver surgery by improving liver function and certain clinical indexes and decreasing related inflammation factors. However, there are limited RCTs on the application of n-3 PUFAs for patients undergoing liver surgery. Further evidence of the benefit of n-3 PUFAs in these patients warrants further exploration.

Current Insights Regarding Intestinal Failure-Associated Liver Disease (IFALD): A Narrative Review

Intestinal failure-associated liver disease (IFALD) is a spectrum of liver disease including cholestasis, biliary cirrhosis, steatohepatitis, and gallbladder disease in patients with intestinal failure (IF). The prevalence of IFALD varies considerably, with ranges of 40-60% in the pediatric population, up to 85% in neonates, and between 15-40% in the adult population. IFALD has a complex and multifactorial etiology; the risk factors can be parenteral nutrition-related or patient-related. Because of this, the approach to managing IFALD is multidisciplinary and tailored to each patient based on the etiology. This review summarizes the current knowledge on the etiology and pathophysiology of IFALD and examines the latest evidence regarding preventative measures, diagnostic approaches, and treatment strategies for IFALD and its associated complications.

Cholestasis: exploring the triangular relationship of gut microbiota-bile acid-cholestasis and the potential probiotic strategies

Cholestasis is a condition characterized by the abnormal production or excretion of bile, and it can be induced by a variety of causes, the factors of which are extremely complex. Although great progress has been made in understanding cholestasis pathogenesis, the specific mechanisms remain unclear. Therefore, it is important to understand and distinguish cholestasis from different etiologies, which will also provide indispensable theoretical support for the development of corresponding therapeutic drugs. At present, the treatment of cholestasis mainly involves several bile acids (BAs) and their derivatives, most of which are in the clinical stage of development. Multiple lines of evidence indicate that ecological disorders of the gut microbiota are strongly related to the occurrence of cholestasis, in which BAs also play a pivotal role. Recent studies indicate that probiotics seem to have certain effects on cholestasis, but further confirmation from clinical trials is required. This paper reviews the etiology of and therapeutic strategies for cholestasis; summarizes the similarities and differences in inducement, symptoms, and mechanisms of related diseases; and provides information about the latest pharmacological therapies currently available and those under research for cholestasis. We also reviewed the highly intertwined relationship between gut microbiota-BA-cholestasis, revealing the potential role and possible mechanism of probiotics in the treatment of cholestasis.

Comparison of Two Lipid Emulsions on the Incidence of Parenteral Nutrition Associated Cholestasis in Neonates

OBJECTIVE

Lipid emulsion contributes to parenteral nutrition associated cholestasis (PNAC). For decades, soybean oil-based intravenous lipid emulsion (SO-ILE) was the predominant product. Recently, a multicomponent lipid emulsion containing soybean oil, medium-chain triglycerides, olive oil and fish oil (SMOF-ILE) has been used off-label in neonatal care. This study evaluates the incidence of PNAC in neonates who received SMOF-ILE or SO-ILE.

METHODS

This was a retrospective review of neonates who received SMOF-ILE or SO-ILE for at least 14 days. Patients receiving SMOF-ILE were matched based on gestational age (GA) and birth weight to a historical cohort receiving SO-ILE. The primary outcomes were the incidences of PNAC among all patients and patients without intestinal failure. The secondary outcomes were clinical outcomes and incidence of PNAC stratified by GA. Clinical outcomes included liver function tests, growth parameters, and development of retinopathy of prematurity and intraventricular hemorrhage.

RESULTS

Forty-three neonates who received SMOF-ILE were matched to 43 neonates who received SOILE. There were no significant differences in baseline characteristics. The incidence of PNAC in the total population was 12% in the SMOF-ILE cohort and 23% in the SO-ILE cohort (p = 0.26). The lipid dosage of SMOF-ILE was significantly higher at time of peak direct serum bilirubin concentration compared with SO-ILE cohort (p = 0.05). Clinically significant differences were noted in laboratory endpoints in several subgroups.

CONCLUSIONS

There was no significant difference in the incidence of PNAC among neonates in a SMOFILE cohort compared with a historical SO-ILE cohort.

Neurologic consequences of neonatal necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a severe gastrointestinal disease of the premature infant with high mortality and morbidity. Children who survive NEC have been shown to demonstrate neurodevelopmental delay, with significantly worse outcomes than from prematurity alone. The pathways leading to NEC-associated neurological impairments remain unclear, limiting the development of preventative and protective strategies. This review aims to summarize the existing clinical and experimental studies related to NEC-associated brain injury. We describe the current epidemiology of NEC, reported long-term neurodevelopmental outcomes among survivors, and proposed pathogenesis of brain injury in NEC. Highlighted are the potential connections between hypoxia-ischemia, nutrition, infection, gut inflammation, and the developing brain in NEC.

Etiology of neonatal cholestasis after emerging molecular diagnostics

BACKGROUND

In the pediatric group, most cholestatic patients had disease onset at 0-3 months of age, and more and more are found to have specific genetic defects after failing to obtain a definite diagnosis by routine evaluation. To investigate the etiological diagnosis for the newborns with cholestasis during the neonatal period after emerging molecular tests comprehensively.

METHODS

We conducted a retrospective study to evaluate clinical characteristics, etiologies and outcomes in infants with neonatal cholestasis after emerging molecular diagnostics from January 1st to December 31st, 2019 in Children's Hospital of Fudan University.

RESULTS

There were 160 cases of neonatal cholestasis with mean gestational age (GA) 32.6±4.8 weeks and birth weight (BW) 1,880±991 g, composing 3.4% of total neonatal admissions in 2019. Overall 97.5% (n=156) patients had a definite diagnosis, including 9 obtaining a genetic diagnosis after adding molecular test in routine evaluation, which made the diagnosis rate for cholestasis increased by 5.6%. The most common etiology of cholestasis in the neonatal period was parenteral nutrition-associated cholestasis (PNAC) 48.8% (n=78), followed by cardiovascular and circulatory disorders 18.1%, biliary anatomic obstruction 12.5%, infection 8.7% and genetic disorders 5.6%. PNAC and biliary anatomic obstruction were the most common etiology of cholestasis for preterm and term infants respectively. The mortality rate is 2.5% (n=4) and 91.9% (n=147) patients totally recovery or improve in follow-up.

CONCLUSIONS

The causes of cholestasis in neonates are complicated, molecular diagnostics can improve the etiological diagnosis for newborns with cholestasis. But still, quite amount of causes are remediable and transient during the neonatal period, gene test may help to rule out genetic causes and enhance confidence in judging prognosis.

Mdr3 gene mutation in preterm infants with parenteral nutrition-associated cholestasis

To investigate the relationship of multidrug resistance 3 (Mdr3) gene mutation and parenteral nutrition‐associated cholestasis (PNAC) in preterm infants. Preterm infants who had received total parenteral nutrition for at least 14 days were enrolled: 76 preterm infants in the PNAC group and 80 preterm infants in the non‐PNAC group. Genomic DNA was extracted from white blood cells. Twenty‐eight exons of the Mdr3 gene were amplified by polymerase chain reaction. PNAC infants of 1 month corrected age with the Mdr3 gene mutation and abnormal liver biochemistry were selected for the experimental liver biopsy group. Five normal adult living liver transplantation donors were enrolled in a normal donor group. The Mdr3 missense mutations c.1031G>A, c.3347G>A, and c.485T>A, and the Mdr3 frameshift mutation c.2793_2794insA were found in the PNAC group. The allele frequency and genotype frequency of c.1031G>A, c.3347G>A, and c.485T>A in the Mdr3 gene in the PNAC group were significantly higher than those in non‐PNAC group (p < 0.05). The rate of Mdr3 gene mutations c.1031G>A, c.485T>A, c.3347G>A, and c.2793_2794insA in the PNAC group was higher than in the non‐PNAC group (21.05% vs. 1.25%, respectively, χ² = 15.747, p < 0.05). Mdr3 gene mutations c.2793_2794insA, c.1031G>A, c.3347G>A, and c.485T>A may be the genetic cause of PNAC.

Long-term assessment of bilirubin and transaminase trends in pediatric intestinal failure patients during the era of hepatoprotective parenteral nutrition

PURPOSE

This study aimed to characterize the relationship between hepatoprotective parenteral nutrition (PN) dependence and long-term serum liver tests in children with intestinal failure (IF).

METHODS

A retrospective review was performed of children with severe IF (> 90 consecutive days of PN) who were followed from 2012 to 2019 at a multidisciplinary intestinal rehabilitation program. Patients were stratified into three groups based on level of PN dependence at most recent follow up: EN (achieved enteral autonomy), mixed (parenteral and enteral nutrition), and PN (> 75% of caloric intake from PN). PN at any point for this cohort was hepatoprotective, defined as soy-based lipids < 1.5 g/kg/day, combination (soy, medium chain fatty acid, olive and fish oil) lipid emulsion, or fish oil-based lipid emulsion. Kaplan-Meier analysis and a generalized estimating equation (GEE) model were utilized to estimate time to normalization and trends, respectively, of two serum markers of liver health: direct bilirubin (DB) and alanine aminotransferase (ALT).

RESULTS

The study included 123 patients (67 EN, 32 mixed, 24 PN). Median follow up time was 4 years. Based on the Kaplan Meier curve, 100% of EN and mixed group patients achieved normal DB levels by 3 years, while 32% of the PN group had elevated DB levels (Fig. 1). At 5 years, 16% of EN patients had elevated ALT levels compared to 73% of PN patients (p < 0.001, Fig. 2). The PN group's ALT levels were 1.76-fold above normal at 3 years (95%CI 1.48-2.03) and 1.65-fold above normal at 5 years (95%CI 1.33-1.97, Fig. 3).

CONCLUSIONS

While serum bilirubin levels tend to normalize, long-term PN dependence in the era of hepatoprotective PN is associated with a persistent transaminase elevation in an overwhelming majority of patients. These data support continued vigilant monitoring of liver health in children with intestinal failure.

LEVEL OF EVIDENCE

III.

Depletion and enrichment of phytosterols in soybean oil lipid emulsions directly associate with serum markers of cholestasis in preterm parenteral nutrition-fed pigs

BACKGROUND

Clinical reports show a positive correlation between phytosterol concentrations and severity of cholestatic liver disease markers in infants during long-term administration of parenteral lipid emulsions. Establishing a causal link between phytosterols and cholestasis has been complicated by confounding factors of lipid emulsion load, fatty acid composition, and vitamin E in many of these studies. The goal of this study is to determine whether altering the phytosterol concentration within a common soybean oil-based emulsion will alter the onset and severity of cholestasis in parenterally fed preterm piglets.

METHODS

Preterm piglets were administered, for 21 days, either enteral nutrition (ENT) or parenteral nutrition (PN) prepared from a soybean oil-based emulsion containing either 24.0% (depleted [DEP]), 100% (Intralipid; normal phytosterol [NP] concentration), or 144% (enriched [ENR]) total phytosterol concentration.

RESULTS

At the end of the study, plasma and liver phytosterol concentrations were highest in the ENR group, followed by NP and then DEP and ENT. Serum direct bilirubin, serum bile acids, and γ-glutamyltransferase were higher in the ENR and NP groups compared with either DEP or ENT groups. All PN lipid groups showed evidence of mild hepatic steatosis but no change in hepatic expression of proinflammatory cytokines or Farnesoid X receptor target genes.

CONCLUSION

The increase in serum direct bilirubin was lower in the DEP group vs the lipid emulsions with normal or ENR phytosterols. Our results provide additional evidence that phytosterols are linked to an increase in serum markers of cholestasis in preterm PN-fed pigs.

Human induced pluripotent stem cell derived hepatocytes provide insights on parenteral nutrition associated cholestasis in the immature liver

Parenteral nutrition-associated cholestasis (PNAC) significantly limits the safety of intravenous parenteral nutrition (PN). Critically ill infants are highly vulnerable to PNAC-related morbidity and mortality, however the impact of hepatic immaturity on PNAC is poorly understood. We examined developmental differences between fetal/infant and adult livers, and used human induced pluripotent stem cell-derived hepatocyte-like cells (iHLC) to gain insights into the contribution of development to altered sterol metabolism and PNAC. We used RNA-sequencing and computational techniques to compare gene expression patterns in human fetal/infant livers, adult liver, and iHLC. We identified distinct gene expression profiles between the human feta/infant livers compared to adult liver, and close resemblance of iHLC to human developing livers. Compared to adult, both developing livers and iHLC had significant downregulation of xenobiotic, bile acid, and fatty acid metabolism; and lower expression of the sterol metabolizing gene ABCG8. When challenged with stigmasterol, a plant sterol found in intravenous soy lipids, lipid accumulation was significantly higher in iHLC compared to adult-derived HepG2 cells. Our findings provide insights into altered bile acid and lipid metabolizing processes in the immature human liver, and support the use of iHLC as a relevant model system of developing liver to study lipid metabolism and PNAC.

Evaluation of the fibrosis-4 index for detection of advanced fibrosis among individuals at risk for intestinal failure-associated liver disease

BACKGROUND

Intestinal failure-associated liver disease (IFALD) refers to the spectrum of liver injury secondary to IF and parenteral nutrition use. Our aim was to evaluate the use of noninvasive indices of liver fibrosis to detect advanced fibrosis among individuals at risk for IFALD.

METHODS

We performed a secondary analysis of a retrospective study, including all liver biopsies performed on individuals undergoing intestinal transplantation (ITx) between January 2000 and May 2014. To determine the clinical utility of detecting advanced fibrosis, receiver operating characteristic curves were developed. Comparison between the area under the curves was performed by DeLong test.

RESULTS

Fifty-three patients had a liver biopsy performed at the time of ITx; 13 of 53 (24.5%) patients had advanced fibrosis. The fibrosis-4 (FIB-4) index positively correlated to the stage of fibrosis on liver biopsy (r = 0.426, P = .002). When compared against the FIB-4 index, the aspartate aminotransferase to platelet ratio index had a significantly decreased ability to correctly identify the presence of advanced fibrosis (P = .019). When determining the cutoff value with 90% specificity for the detection of advanced fibrosis, a FIB-4 index of ≥4.4 had a sensitivity of 0.462 and a positive predictive value of 0.6.

CONCLUSION

In this retrospective cohort study, we found a positive correlation between the FIB-4 index and the liver fibrosis stage as characterized by the Brunt classification. This evaluation of the FIB-4 index against liver biopsies supports the use of the FIB-4 index in the detection of liver fibrosis in IF.

SMOFlipid vs Intralipid 20%: Effect of Mixed-Oil vs Soybean-Oil Emulsion on Parenteral Nutrition-Associated Cholestasis in the Neonatal Population

BACKGROUND

Parenteral nutrition (PN) is critical for the growth and development of premature neonates who are unable to reach nutrition goals enterally. Using soybean-oil emulsions in PN is a risk factor for cholestasis, leading to alternative dosing strategies including a reduction in total lipid prescribed. Recently, SMOFlipid has been utilized with the goal of avoiding cholestasis while maintaining energy intake. The aim of our study was to compare the incidence of PN-associated cholestasis (PNAC) in patients admitted to the neonatal intensive care unit (NICU) who received either Intralipid 20% or SMOFlipid.

METHODS

This single-center, retrospective study evaluated all NICU patients who received PN for ≥14 days. Patients who received SMOFlipid were compared with those who received Intralipid. The primary end point was incidence of PNAC. Secondary end points included (1) prevalence of elevated liver function tests; (2) effect on select laboratory parameters; (3) development of PNAC by age; and (4) incidence of retinopathy of prematurity.

RESULTS

A total of 136 neonates were included. Nine of 55 patients (16.4%) in the Intralipid group and 2 of 81 patients (2.5%) in the SMOFlipid group developed cholestasis, defined as direct bilirubin > 2 mg/dL or direct bilirubin > 20% of total bilirubin, when total bilirubin is >5 mg/dL, on or before 30 days post initiation of PN (P = .007).

CONCLUSION

Use of SMOFlipid as the lipid emulsion component of PN may be beneficial in prevention of PNAC in NICU patients that are receiving PN for ≥2 weeks.

Risk factors of parenteral nutrition-associated cholestasis in very-low-birthweight infants

AIM

We aimed to explore risk factors associated with parenteral nutrition-associated cholestasis (PNAC) in very-low-birthweight (VLBW) infants.

METHODS

VLBW infants receiving parenteral nutrition (PN) for at least 14 days were enrolled in a retrospective dual-centre study and divided into two groups chronologically: group A (2000-2007) and group B (2008-2015). The incidence of PNAC and related factors were investigated. We compared the differences between PNAC and non-PNAC groups. A multivariate binary logistic regression analysis was carried out to identify the potential risk factors of PNAC.

RESULTS

A total of 387 VLBW infants (53 in group A and 334 in group B) were enrolled in the study. The total incidence of PNAC was 6.7%, 9.4% in group A and 6.3% in group B. The dosage of amino acid (P = 0.009), glucose (P = 0.006), PN calories (P = 0.021) and the ratio of glucose/fat (P = 0.014) were significantly higher in group B than in group A. Non-protein energy to nitrogen ratio (P = 0.017) was lower in group B. Birthweight was significantly lower in the PNAC group than in the non-PNAC group (P = 0.021). Subgroup analysis showed that gestational age and duration of PN were significantly different between the PNAC and non-PNAC groups (P < 0.05). Logistic regression showed that prolonged duration of PN (≥43 days) (odds ratio 3.155, 95% confidence interval 1.009-9.861, P = 0.048) was an independent risk factor of PNAC.

CONCLUSIONS

For VLBW infants, prolonged duration of PN is a risk factor for the development of PNAC. PNAC may be prevented by weaning off PN as early as possible in VLBW infants.

Time to full enteral feeding after necrotizing enterocolitis in preterm-born children is related to neurodevelopment at 2-3 years of age

BACKGROUND

Necrotizing enterocolitis (NEC) is associated with poorer neurodevelopment. It is, however, unclear which factors besides surgery affect neurodevelopment in preterm-born children surviving NEC.

AIMS

We determined whether time to full enteral feeding (FEFt) and post-NEC complications after NEC were associated with neurodevelopment.

STUDY DESIGN

Prospective observational cohort study.

SUBJECTS

Two to three year old preterm-born children who survived NEC (Bells stage ≥ 2). We categorized children in two groups, one group shorter and equal and one group longer than the group's median FEFt. Post-NEC complications included recurrent NEC and/or post-NEC stricture.

OUTCOME MEASURES

Bayley Scales of Infants and Toddler Development III (Bayley-III) and Child Behavior Checklist (CBCL). Associations between Bayley-III and CBCL scores with FEFt and Post-NEC complications were determined using linear regression analyses, adjusted for severity of illness and potential confounders.

RESULTS

We included 44 children, median gestational age of 27.9 [IQR: 26.7-29.3] weeks, birth weight 1148 [IQR: 810-1461] grams. Median FEFt after NEC was 20 [IQR: 16-30] days. Median follow-up age was 25.7 [IQR: 24.8-33.5] months. FEFt > 20 days was associated with lower cognitive and lower motor composite scores of the Bayley-III (B: -8.6, 95% CI -16.7 to -0.4, and B: -9.0, 95% CI, -16.7 to -1.4). FEFt was not associated with CBCL scores. Post-NEC complications (n = 11) were not associated with Bayley-III scores nor with CBCL scores.

CONCLUSIONS

Prolonged FEFt after NEC in preterm-born children surviving NEC is associated with lower cognitive and lower motor composite scores at the age of 2-3 years. These results show the importance of limiting the duration of the nil per mouth regimen if and when possible.

Novel Strategies to Prevent Total Parenteral Nutrition-Induced Gut and Liver Inflammation, and Adverse Metabolic Outcomes

Total parenteral nutrition (TPN) is a life-saving therapy administered to millions of patients. However, it is associated with significant adverse effects, namely liver injury, risk of infections, and metabolic derangements. In this review, the underlying causes of TPN-associated adverse effects, specifically gut atrophy, dysbiosis of the intestinal microbiome, leakage of the epithelial barrier with bacterial invasion, and inflammation are first described. The role of the bile acid receptors farnesoid X receptor and Takeda G protein-coupled receptor, of pleiotropic hormones, and growth factors is highlighted, and the mechanisms of insulin resistance, namely the lack of insulinotropic and insulinomimetic signaling of gut-originating incretins as well as the potentially toxicity of phytosterols and pro-inflammatory fatty acids mainly released from soybean oil-based lipid emulsions, are discussed. Finally, novel approaches in the design of next generation lipid delivery systems are proposed. Propositions include modifying the physicochemical properties of lipid emulsions, the use of lipid emulsions generated from sustainable oils with favorable ratios of anti-inflammatory n-3 to pro-inflammatory n-6 fatty acids, beneficial adjuncts to TPN, and concomitant pharmacotherapies to mitigate TPN-associated adverse effects.

Parenteral lipids shape gut bile acid pools and microbiota profiles in the prevention of cholestasis in preterm pigs

Multi-component lipid emulsions, rather than soy-oil emulsions, prevent cholestasis by an unknown mechanism. Here, we quantified liver function, bile acid pools, and gut microbial and metabolite profiles in premature parenterally fed pigs given a soy-oil lipid emulsion, Intralipid (IL), a multi component lipid emulsion, SMOFlipid (SMOF), a novel emulsion with a modified fatty-acid composition [experimental emulsion (EXP)], or a control enteral diet (ENT) for 22 days. We assayed serum cholestasis markers, measured total bile acid levels in plasma, liver, and gut contents, and analyzed colonic bacterial 16S rRNA gene sequences and metabolomic profiles. Serum cholestasis markers (i.e., bilirubin, bile acids, and γ-glutamyl transferase) were highest in IL-fed pigs and normalized in those given SMOF, EXP, or ENT. Gut bile acid pools were lowest in the IL treatment and were increased in the SMOF and EXP treatments and comparable to ENT. Multiple bile acids, especially their conjugated forms, were higher in the colon contents of SMOF and EXP than in IL pigs. The colonic microbial communities of SMOF and EXP pigs had lower relative abundance of several gram-positive anaerobes, including Clostridrium XIVa, and higher abundance of Enterobacteriaceae than those of IL and ENT pigs. Differences in lipid and microbial-derived compounds were also observed in colon metabolite profiles. These results indicate that multi-component lipid emulsions prevent cholestasis and restore enterohepatic bile flow in association with gut microbial and metabolomic changes. We conclude that sustained bile flow induced by multi-component lipid emulsions likely exerts a dominant effect in reducing bile acid-sensitive gram-positive bacteria.

A Comparison of Smoflipid® and Intralipid® in the Early Management of Infants with Intestinal Failure

PURPOSE

Cholestasis is problematic for infants with intestinal failure (IF). The soy-based lipid Intralipid® (IL) has been implicated. An alternative, Smoflipid® (SMOF), is increasingly used. However, its role in cholestasis prevention is unclear. This study compares the incidence and degree of cholestasis between infants with IF receiving SMOF or IL.

METHODS

Infants with IF receiving SMOF or IL during the first 8 weeks of parenteral nutrition (PN) support between 2014 and 2017 were reviewed. Clinical characteristics, cholestasis incidence (conjugated bilirubin (Cbili) >2 mg/dL for >2 weeks), and nutritional parameters were compared using Welch's t-test.

RESULTS

91% (21/23) of IL and 76% (16/21) of SMOF babies became cholestatic (p = 0.18). There was no significant difference in median peak Cbili, but SMOF babies normalized more quickly (p = 0.04). Median z-scores for weight were similar throughout the study. SMOF patients getting full PN had a lower incidence of cholestasis compared to IL patients (78% vs. 92%, p = 0.057), but those with cholestasis had similar peak Cbili, time to resolution, and growth.

CONCLUSION

Early use of Smoflipid® did not reduce the incidence of cholestasis compared to Intralipid® in infants with IF, but hyperbilirubinemia did resolve more quickly. SMOF may be most beneficial for infants tolerating no enteral nutrition.

LEVEL OF EVIDENCE

Level III Retrospective Comparative Treatment Study.

TYPE OF STUDY

Retrospective Review.

Mechanisms of Parenteral Nutrition-Associated Liver and Gut Injury

Parenteral nutrition (PN) has revolutionized the care of patients with intestinal failure by providing nutrition intravenously. Worldwide, PN remains a standard tool of nutrition delivery in neonatal, pediatric, and adult patients. Though the benefits are evident, patients receiving PN can suffer serious cholestasis due to lack of enteral feeding and sometimes have fatal complications from liver injury and gut atrophy, including PN-associated liver disease or intestinal failure-associated liver disease. Recent studies into gut-systemic cross talk via the bile acid-regulated farnesoid X receptor (FXR)-fibroblast growth factor 19 (FGF19) axis, gut microbial control of the TGR5-glucagon-like peptide (GLP) axis, sepsis, and role of prematurity of hepatobiliary receptors are greatly broadening our understanding of PN-associated injury. It has also been shown that the composition of ω-6/ω-3 polyunsaturated fatty acids given parenterally as lipid emulsions can variably drive damage to hepatocytes and cell integrity. This manuscript reviews the mechanisms for the multifactorial pathogenesis of liver disease and gut injury with PN and discusses novel ameliorative strategies.

Ultrasound Elastography as a Non-Invasive Method to Monitor Liver Disease in Children with Short Bowel Syndrome: Updated Results

PURPOSE

The purpose of the study was to determine the accuracy of acoustic radiation force impulse (ARFI) ultrasound elastography in assessing the degree of liver disease in children with short bowel syndrome (SBS).

METHODS

A prospective observational cohort study of patients with SBS who underwent a liver biopsy and ARFI elastography was performed. Mean shear wave speed (SWS) and stage of fibrosis was evaluated using t-tests. Receiver operating characteristic curves (ROC) were generated and the area under the curves (AUC) estimated in order to assess the accuracy of SWS measurements to discriminate between stages of fibrosis.

RESULTS

Thirty-seven paired elastography and biopsy samples from 31 patients were included. The median age was 0.6 years, and 61% were male. There was a significant positive correlation between stage of fibrosis and mean SWS (β=0.16 m/s increase per stage, p=<0.001). ROC analysis revealed that mean SWS had good accuracy for discriminating between mild liver fibrosis (F0-F1) and moderate to severe fibrosis (F2-F4) (AUC=0.80, 95% CI 0.65-0.95). In addition, ROC analysis demonstrated that mean SWS can also accurately discriminate between mild to moderate fibrosis (F0-F2) and more severe fibrosis (F3-F4) (AUC=0.84, 95% CI 0.71-0.96).

CONCLUSION

ARFI elastography is an accurate, non-invasive method to monitor liver disease in children with SBS.

TYPE OF STUDY

Retrospective Cohort Study LEVEL OF EVIDENCE: II.

New-generation fish oil and olive oil lipid for prevention of oxidative damage in preterm infants: Single center clinical trial at university hospital in Turkey

BACKGROUND

Parenteral nutrition (PN) has been widely used in preterm infants. The lipid solutions used for PN, however, are associated with oxidative stress and morbidity. The aim of this study was to compare the effectiveness of a new-generation lipid emulsion (SMOFLipid) and olive-oil based lipid emulsion for prevention of PN-associated oxidative damage.

METHODS

Preterm infants < 32 weeks of gestational age were included in this prospective randomized study. All infants were randomized to SMOFlipid or olive-oil based lipid emulsion (ClinOleic). Lipid peroxidation products were evaluated in all infants. In addition, total antioxidant capacity (TAC), and both pro- and anti-inflammatory cytokines were studied at days 0, 7 and 14.

RESULTS

A total of 89 infants (SMOFlipid, n = 42; ClinOleic, n = 47) were enrolled. TAC was higher in the SMOFlipid group compared with the ClinOleic group at all time points, and the difference on day 7 was statistically significant. Although the anti-inflammatory cytokine interleukin-10 was higher in the SMOFlipid group, this difference was not significant. Bronchopulmonary dysplasia (BPD) was lower in the SMOFlipid group (14.1%) than in the ClinOleic group (31.2%), but this finding was non-significant p > 0.05. The rate of severe BPD was significantly lower in the SMOFlipid group.

CONCLUSION

To our best of knowledge, this is the first study to suggest that SMOFlipid might decrease oxidative damage and oxidative-stress-associated morbidity compared with olive oil-based emulsion in preterm infants.

The Role of Parenteral Lipids in the Development of Hepatic Dysfunction and Hepatic Steatosis in a Mouse Model of Total Parenteral Nutrition

Parenteral nutrition-associated liver disease, a common and life-threating complication among people who require long-term parenteral nutrition, has been associated with abnormal liver function, cholestasis, steatosis and fibrosis. Intravenous soybean lipids may be associated with the development of liver disease. We therefore examined whether different doses of parenteral lipids would affect the development of liver disease, and further investigated the possible pathogenesis of it. C57BL/6J mice with a central catheter placed in the right jugular vein were divided into three groups. The control group received normal mouse chow with intravenous normal saline; The lipids group received parenteral nutrition solution (0.14 g lipids per day); the H-lipids group received parenteral nutrition solution with twice the amount of lipids (0.3 g lipids per day). Changes in body weight, serum biochemical parameters, liver histology and farnesoid X receptor gene expression in the liver were assessed. The values of serum direct bilirubin, total bilirubin and cholesterol were markedly increased in the H-lipids group at day 7. The predominant histologic finding in the H-lipids group was steatosis, and the steatosis score in the H-lipids group was much higher than in the other two groups at either day 5 or day 7. Hepatic expression of farnesoid X receptor mRNA decreased after 7 d of parenteral nutrition. High doses of parenteral lipids are more likely to develop liver disease in a mouse model of parenteral nutrition. Farnesoid X receptor may play a key role in the development of parenteral nutrition-associated liver disease.

The Long and Short of IT: intestinal failure-associated liver disease (IFALD) in adults-recommendations for early diagnosis and intestinal transplantation

Intestinal failure-associated liver disease (IFALD) often presents in adults unexpectedly with advanced disease. Non-invasive tests can be falsely reassuring. Patients with 'ultrashort' intestine (<20 cm) ending in a stoma are at particular risk of developing IFALD, which may occur rapidly. Recent experience and studies suggest that IFALD can be reversed by isolated intestine transplant occurring before the development of high grade fibrosis or cirrhosis. Post-transplant survival is superior for isolated intestinal grafts compared with liver containing intestinal grafts; waiting time and waiting list mortality is higher for a combined graft, and donor liver supply is limited. Therefore, the aim of clinicians treating patients with intestinal failure should be to identify IFALD early and refer to an intestinal transplant centre while isolated intestine transplantation can be contemplated and before the liver disease has progressed to a stage requiring consideration of combined liver and intestinal transplantation.

Prevalence and Prognostic Value of Abnormal Liver Test Results in Critically Ill Children and the Impact of Delaying Parenteral Nutrition

OBJECTIVES

In the Early versus Late Parenteral Nutrition in the Pediatric ICU randomized controlled trial, delaying parenteral nutrition to beyond day 7 (late parenteral nutrition) was clinically superior to supplemental parenteral nutrition initiated within 24 hours (early parenteral nutrition), but resulted in a higher rise in bilirubin. We aimed to document prevalence and prognostic value of abnormal liver tests in the PICU and the impact hereon of withholding early parenteral nutrition.

DESIGN

Preplanned secondary analysis of the Early versus Late Parenteral Nutrition in the Pediatric ICU randomized controlled trial. Total bilirubin, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transpeptidase, alkaline phosphatase plasma concentrations were measured systematically in PICU. Liver test analyses were adjusted for baseline characteristics including severity of illness.

SETTING

Three PICUs in Belgium, the Netherlands, and Canada.

PATIENTS

As neonatal jaundice was considered a confounder, only the 1,231 of the 1,440 Early versus Late Parenteral Nutrition in the Pediatric ICU-patients 28 days to 17 years old were included.

INTERVENTIONS

Late parenteral nutrition as compared with early parenteral nutrition.

MEASUREMENTS AND MAIN RESULTS

During the first seven PICU days, the prevalence of cholestasis (> 2 mg/dL [34.2 μmol/L] bilirubin) ranged between 3.8% and 4.9% and of hypoxic hepatitis (≥ 20-fold upper limit of normality for alanine aminotransferase and aspartate aminotransferase) between 0.8% and 2.2%, both unaffected by the use of parenteral nutrition. Throughout the first week in PICU plasma bilirubin concentrations were higher in late parenteral nutrition patients (p < 0.05), but became comparable to early parenteral nutrition patients as soon as parenteral nutrition was started on day 8. Plasma concentrations of gamma-glutamyl transpeptidase, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase were unaffected by parenteral nutrition. High day 1 plasma concentrations of gamma-glutamyl transpeptidase, alanine aminotransferase, and aspartate aminotransferase (p ≤ 0.01), but not alkaline phosphatase, were independent risk factors for PICU mortality. Day 1 plasma bilirubin concentrations displayed a U-shaped association with PICU mortality, with higher mortality associated with bilirubin less than 0.20 mg/dL and greater than 0.76 mg/dL (< 3.42 μmol/L and > 13 μmol/L) (p ≤ 0.01).

CONCLUSIONS

Overt cholestasis and hypoxic hepatitis were rare and unrelated to the nutritional strategy. However, withholding parenteral nutrition up to 1 week in PICU increased plasma bilirubin. A mild elevation of bilirubin on the first PICU day was associated with lower risk of death and may reflect a stress response, rather than true cholestasis.

Developing a Novel Ambulatory Total Parenteral Nutrition-Dependent Short Bowel Syndrome Animal Model

BACKGROUND

Short bowel syndrome (SBS) results from extensive bowel resection. Patients with SBS require total parenteral nutrition (TPN) for survival. Understanding mechanisms contributing to TPN-associated liver injury and gut atrophy are critical in developing SBS therapies. Existing SBS models using tethered animals have significant limitations and are unlike ambulatory human SBS patients. We hypothesized that we could induce SBS in piglets and develop an ambulatory TPN-SBS model.

MATERIAL AND METHODS

Eighteen neonatal pigs received duodenal and jugular catheters. They were fitted with a jacket holding TPN and a miniaturized pump. Six piglets had 90% small bowel resection and catheter placement (SBS group). Non-SBS piglets were randomized into enteral nutrition (EN) or TPN.

RESULTS

Bowel resection was successfully accomplished in SBS animals. Weight gain was similar in all groups. SBS animals had increased serum bilirubin compared to EN. Mean conjugated bilirubin ± SD was 0.045 ± 0.01 for EN, (P = 0.03 EN versus TPN and P = 0.03 SBS versus EN) and 1.09 ± 1.25 for TPN, (P = 0.62 TPN versus SBS). Gut density was reduced in the TPN group compared to EN and SBS groups. Mean gut density ± SD was 0.11 ± 0.04 for TPN (P = 0.0004 TPN versus SBS and P = 0.00007 TPN versus EN) and not statistically different for EN versus SBS (P = 0.32).

CONCLUSIONS

We created a novel, ambulatory TPN-SBS model using piglets, mimicking long-term TPN delivery in human SBS patients. Our model demonstrated TPN-related conjugated hyperbilirubinemia and compensatory gut hypertrophy, as noted in humans with SBS. This model holds great potential for future research.

Role of the Gut⁻Liver Axis in Driving Parenteral Nutrition-Associated Injury

For decades, parenteral nutrition (PN) has been a successful method for intravenous delivery of nutrition and remains an essential therapy for individuals with intolerance of enteral feedings or impaired gut function. Although the benefits of PN are evident, its use does not come without a significant risk of complications. For instance, parenteral nutrition-associated liver disease (PNALD)—a well-described cholestatic liver injury—and atrophic changes in the gut have both been described in patients receiving PN. Although several mechanisms for these changes have been postulated, data have revealed that the introduction of enteral nutrition may mitigate this injury. This observation has led to the hypothesis that gut-derived signals, originating in response to the presence of luminal contents, may contribute to a decrease in damage to the liver and gut. This review seeks to present the current knowledge regarding the modulation of what is known as the “gut–liver axis” and the gut-derived signals which play a role in PN-associated injury.

The intestinal microbiome and paediatric liver disease

The intestinal microbiome has been the intense focus of recent study, but how the microbiota affects connected organs, such as the liver, has not been fully elucidated. The microbiome regulates intestinal permeability and helps to metabolise the human diet into small molecules, thus directly affecting liver health. Several studies have linked intestinal dysbiosis to the severity and progression of liver diseases, such as non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, primary sclerosing cholangitis, total parenteral nutrition-associated liver disease, and cystic fibrosis-associated liver disease. However, there is limited information and interpretation with regard to how the microbiome could contribute to liver disease in the paediatric population. Notably, the gut microbiota is distinct at birth and does not establish an adult profile until the third year of life. Clinical research suggests that paediatric liver disease differs in both severity and rate of progression compared with adult forms, suggesting independent mechanisms of pathogenesis. We discuss data linking the intestinal microbiome to liver disease development and therapeutic efforts to modify the microbiome in children.

Utility of liver biopsy in the evaluation of pediatric total parenteral nutrition cholestasis

BACKGROUND

Cholestasis is a serious complication of total parenteral nutrition (TPN) in neonates. Liver biopsies may be requested to assess the severity of cholestasis and fibrosis. We hypothesized that liver biopsy would not lead to changes in management or improved patient outcomes.

METHODS

A single institution retrospective review of infants with TPN cholestasis from January 2008 to January 2016.

OUTCOMES

length of stay, complications, change in management and mortality. Statistical analysis was performed using Fisher's exact test.

RESULTS

Twenty-seven out of 95 patients with TPN cholestasis underwent liver biopsy. Liver biopsy was associated with increased utilization or ursodeoxycholic acid (p = 0.001). There were no differences in length of stay (LOS) or mortality. One patient had a complication following anesthesia for liver biopsy, there were no bleeding complications recorded.

CONCLUSIONS

Liver biopsy in patients with TPN cholestasis was associated with an increase in utilization of ursodeoxycholic acid. The effects of this are not fully understood; however, liver biopsy was not associated with improved patient outcomes such as LOS or mortality.

No Gut No Gain! Enteral Bile Acid Treatment Preserves Gut Growth but Not Parenteral Nutrition-Associated Liver Injury in a Novel Extensive Short Bowel Animal Model

BACKGROUND

Parenteral nutrition (PN) provides nutrition intravenously; however, this life-saving therapy is associated with significant liver disease. Recent evidence indicates improvement in PN-associated injury in animals with intact gut treated with enteral bile acid (BA), chenodeoxycholic acid (CDCA), and a gut farnesoid X receptor (FXR) agonist, which drives the gut-liver cross talk (GLCT). We hypothesized that similar improvement could be translated in animals with short bowel syndrome (SBS).

METHODS

Using piglets, we developed a novel 90% gut-resected SBS model. Fifteen SBS piglets receiving PN were given CDCA or control (vehicle control) for 2 weeks. Tissue and serum were analyzed posteuthanasia.

RESULTS

CDCA increased gut FXR (quantitative polymerase chain reaction; P = .008), but not downstream FXR targets. No difference in gut fibroblast growth factor 19 (FGF19; P = .28) or hepatic FXR (P = .75), FGF19 (P = .86), FGFR4 (P = .53), or Cholesterol 7 α-hydroxylase (P = .61) was noted. PN resulted in cholestasis; however, no improvement was noted with CDCA. Hepatic fibrosis or immunostaining for Ki67, CD3, or Cytokeratin 7 was not different with CDCA. PN resulted in gut atrophy. CDCA preserved (P = .04 vs control) gut mass and villous/crypt ratio. The median (interquartile range) for gut mass for control was 0.28 (0.17-0.34) and for CDCA was 0.33 (0.26-0.46).

CONCLUSIONS

We note that, unlike in animals with intact gut, in an SBS animal model there is inadequate CDCA-induced activation of gut-derived signaling to cause liver improvement. Thus, it appears that activation of GLCT is critically dependent on the presence of adequate gut. This is clinically relevant because it suggests that BA therapy may not be as effective for patients with SBS.

Total parenteral nutrition for the very low birth weight infant

Preterm infants, especially very low birth weight (VLBW; <1500 g) and extremely low birth weight (ELBW; <1000 g) infants, are susceptible to growth failure in postnatal life if nutritional demands are not met. Poor postnatal growth in preterm infants is associated with adverse neurodevelopmental outcomes during childhood. Early parental nutrition is of paramount importance to provide appropriate protein and energy in VLBW infants when enteral nutrition is not feasible or is suboptimal. An "early and aggressive" approach of parenteral nutrition in preterm infants has been shown to prevent protein catabolism, induce positive nitrogen balance and improve postnatal growth.

Retrospective Dual-Center Study of Parenteral Nutrition-Associated Cholestasis in Premature Neonates: 15 Years' Experience

BACKGROUND

The pathogenesis of parenteral nutrition-associated cholestasis (PNAC) has not been clarified. The objective of this study was to explore the incidence of PNAC in premature infants without surgery and to identify associated risk factors.

MATERIALS AND METHODS

Premature neonates who received parenteral nutrition (PN) at least 14 days were included in a retrospective, dual-center study. Cholestasis was diagnosed as conjugated bilirubin ≥2 mg/dL. Infants with metabolic liver disease, cyanotic congenital heart disease, congenital syphilis, hepadnaviridae infection, and those who underwent surgery were excluded. Infants were divided into 3 groups chronologically: group A (2000-2004, n = 50), group B (2005-2009, n = 283), and group C (2010-2014, n = 741). A case-controlled study was conducted by comparing infants with PNAC to those without PNAC.

RESULTS

Of 1074 premature neonates, PNAC was confirmed in 53 infants (4.93%). There were 6.8% very low birth weight (BW) infants and 20.0% extremely low BW infants who developed PNAC. The incidence of PNAC decreased slightly during 2000-2014 (8.0%, 6.4%, and 4.2% in groups A, B, and C, respectively). Compared with those without PNAC, infants with PNAC (n = 53) had significantly younger gestational age, lower BW, longer PN duration, and higher rate of sepsis. Logistic regression showed male sex, PN duration ≥43 days, and sepsis were statistically correlated with PNAC.

CONCLUSIONS

Prolonged duration (≥43 days), male sex, and sepsis are probably independent risk factors for developing PNAC in premature neonates.

Preserved Gut Microbial Diversity Accompanies Upregulation of TGR5 and Hepatobiliary Transporters in Bile Acid-Treated Animals Receiving Parenteral Nutrition

BACKGROUND

Parenteral nutrition (PN) is a lifesaving therapy but is associated with gut atrophy and cholestasis. While bile acids (BAs) can modulate intestinal growth via gut receptors, the gut microbiome likely influences gut proliferation and inflammation. BAs also regulate the bile salt export pump (BSEP) involved in cholestasis. We hypothesized that the BA receptor agonist oleanolic acid (OA) regulates gut TGR5 receptor and modulates gut microbiota to prevent PN-associated injury.

MATERIALS AND METHODS

Neonatal piglets were randomized to approximately 2 weeks of isocaloric enteral nutrition (EN), PN, or PN + enteral OA. Serum alanine aminotransferase, bilirubin, BAs, hepatic BSEP, gut TGR5, gut, liver morphology, and fecal microbiome utilizing 16S rRNA sequencing were evaluated. Kruskal-Wallis test, pairwise Mann-Whitney U test, and multilevel logistic regression analysis were performed.

RESULTS

PN support resulted in gut atrophy substantially prevented by OA. The median (interquartile range) for villous/crypt ratio was as follows: EN, 3.37 (2.82-3.80); PN, 1.73 (1.54-2.27); and OA, 2.89 (2.17-3.34; P = .006). Pairwise comparisons yielded P = .002 (EN vs PN), P = .180 (EN vs OA), P = .026 (PN vs OA). OA upregulated TGR5 and BSEP without significant improvement in serum bilirubin ( P = .095). A decreased microbial diversity and shift toward proinflammatory phylum Bacteroidetes were seen with PN, which was prevented by OA.

CONCLUSIONS

OA prevented PN-associated gut mucosal injury, Bacterioides expansion, and the decreased microbial diversity noted with PN. This study demonstrates a novel relationship among PN-associated gut dysfunction, BA treatment, and gut microbial changes.

Determination of 7α-OH cholesterol by LC-MS/MS: Application in assessing the activity of CYP7A1 in cholestatic minipigs

An LC-MS/MS method was developed and validated to determine 7α-OH cholesterol in liver microsome. This method was convenient and fast with high specificity and sensitivity. Briefly, a gradient elution was performed on a Synergi polar-C18 column (50×4.6mm i.d., 3μm). The mobile phase (consisting of 0.1% HCOOH solution and acetonitrile) eluted in gradient at a flow rate of 1ml/min. MS detection was operated on APCI (+) mode; the MRM transitions for 7α-OH cholesterol and D7-cholesterol (I.S.) were 385.1≥159.1 and 376.4≥266.3, respectively. The linear response range of 7α-OH cholesterol was covered from 1.563 to 100.0ng/ml. All of the validation items meet the requirement of FDA guidance for bioanalytical method validation. This method was applied to enzymatic studies for determination of cholesterol 7alpha-hydroxylation activity catalyzed by CYP7A1 in the cholestatic minipigs liver microsomes.

Comparison of Formulas Based on Lipid Emulsions of Olive Oil, Soybean Oil, or Several Oils for Parenteral Nutrition: A Systematic Review and Meta-Analysis

Many studies have reported that olive oil-based lipid emulsion (LE) formulas of soybean oil, medium-chain triglycerides, olive oil, and fish oil (SMOF) may be a viable alternative for parenteral nutrition. However, some randomized controlled clinical trials (RCTs) have raised concerns regarding the nutritional benefits and safety of SMOFs. We searched principally the MEDLINE, Cumulative Index to Nursing and Allied Health Literature, Scopus, EMBASE, and Cochrane Central Register of Controlled Trials databases from inception to March 2014 for the relevant literature and conducted a meta-analysis of 15 selected RCTs that 1) compared either olive oil- or SMOF-based LEs with soybean oil-based LEs and 2) reported plasma concentrations of α-tocopherol, oleic acid, and ω-6 (n-6) and ω-3 (n-3) long-chain polyunsaturated fatty acids (PUFAs) and liver concentrations of total bilirubin and the enzymes alanine transaminase, aspartate transaminase, alkaline phosphatase, and γ-glutamyl transferase. The meta-analysis suggested that SMOF-based LEs were associated with higher plasma concentrations of plasma α-tocopherol, oleic acid, and the ω-3 PUFAs eicosapentaenoic and docosahexaenoic acid. Olive oil- and SMOF-based LEs correlated with lower plasma concentrations of long-chain ω-6 PUFAs and were similar to soybean oil-based LEs with regard to their effects on liver function indicators. In summary, olive oil- and SMOF-based LEs have nutritional advantages over soybean oil-based LEs and are similarly safe. However, their performance in clinical settings requires further investigation.

Working group reports: evaluation of the evidence to support practice guidelines for nutritional care of preterm infants-the Pre-B Project

The "Evaluation of the Evidence to Support Practice Guidelines for the Nutritional Care of Preterm Infants: The Pre-B Project" is the first phase in a process to present the current state of knowledge and to support the development of evidence-informed guidance for the nutritional care of preterm and high-risk newborn infants. The future systematic reviews that will ultimately provide the underpinning for guideline development will be conducted by the Academy of Nutrition and Dietetics' Evidence Analysis Library (EAL). To accomplish the objectives of this first phase, the Pre-B Project organizers established 4 working groups (WGs) to address the following themes: 1) nutrient specifications for preterm infants, 2) clinical and practical issues in enteral feeding of preterm infants, 3) gastrointestinal and surgical issues, and 4) current standards of infant feeding. Each WG was asked to 1) develop a series of topics relevant to their respective themes, 2) identify questions for which there is sufficient evidence to support a systematic review process conducted by the EAL, and 3) develop a research agenda to address priority gaps in our understanding of the role of nutrition in health and development of preterm/neonatal intensive care unit infants. This article is a summary of the reports from the 4 Pre-B WGs.