New generation lipid emulsions prevent PNALD in chronic parenterally fed preterm pigs

Safety and Efficacy of a Composite Lipid Emulsion with Fish Oil in Hospitalized Neonates and Infants Requiring Prolonged Parenteral Nutrition - A Randomized, Double-Blind, Multicenter, Controlled Trial

BACKGROUND

Intravenous lipids are critical to the care of extremely premature and other high-risk infants.

OBJECTIVE

The study evaluated safety and efficacy of parenteral nutrition (PN) with composite intravenous lipid emulsion (CO-ILE) with fish oil compared to pure soybean oil lipid emulsion (SOLE).

METHODS

Randomized, controlled, double-blind, multicenter study (NCT02579265) in neonates/ infants anticipated to require ≥28 days of PN due to gastrointestinal malformations or injury. Duration of the initial and extended treatment phase was 28 days and 84 days (for patients with PN indication after day 28).

RESULTS

83/ 78 patients (mean postnatal age: 11.4/ 8.3 days, 54/ 59 preterm) received CO-ILE and SOLE, respectively. 33 patients per group completed 28 days on treatment. Risk of having conjugated bilirubin values > 2 mg/dL confirmed by a second sample 7 days after the first during the initial treatment phase (primary outcome) was 2.4% (2 of 83) with CO-ILE and 3.8% (3 of 78) with SOLE (risk ratio 0.59 [95% CI: 0.09, 3.76]). Between days 29 and 84, the number of patients with confirmed conjugated bilirubin values > 2 mg/dL did not increase in the CO-ILE group (n=2) and increased in the SOLE group (n=9). At the end of the initial treatment phase, conjugated bilirubin concentrations were 45.6% lower under CO-ILE than under SOLE (p=0.006). There was no clinical or laboratory evidence of essential fatty acid deficiency in patients in the CO-ILE group. Median time to discharge alive was 56.7 and 66.4 days with CO-ILE and SOLE, respectively (hazard ratio: 1.16; 95% CI: 0.81, 1.68).

CONCLUSIONS

CO-ILE was associated with a possible lower risk of cholestasis and significantly lower conjugated bilirubin at the end of the initial treatment phase in high-risk neonates and infants as compared to patients treated with SOLE. In summary, these data indicate that CO-ILE can be considered safe and may be preferable over SOLE in high-risk neonates.

CLINICAL TRIAL REGISTRY NUMBER

Clinicaltrials.gov, study ID NCT02579265.

Selective Agonism of Liver and Gut FXR Prevents Cholestasis and Intestinal Atrophy in Parenterally Fed Neonatal Pigs

BACKGROUND & AIMS

We aimed to investigate the relative efficacy of feeding different bile acids in preventing PNALD in neonatal pigs.

METHODS

Newborn pigs given total parenteral nutrition (TPN) combined with minimal enteral feeding of chenodeoxycholic acid (CDCA), or increasing doses of obeticholic acid (OCA) for 19 days.

RESULTS

Enteral OCA (5 and 15 mg/kg), but not CDCA (30 mg/kg) reduced blood cholestasis markers compared to TPN controls and increased bile acids in the gallbladder and intestine. Major bile acids in the liver and distal intestine were CDCA, HCA, HDCA and OCA, and their relative proportions were increased by the type of bile acid (CDCA or OCA) given enterally. High doses of OCA increased the total NR1H4-agonistic bile acid profile in the liver and intestine above 50% total bile acids. Both CDCA and OCA treatments suppressed hepatic cyp7a1 expression, but only OCA increased hepatobiliary transporters, ABCB11, ABCC$ and ABCB1. Plasma phytosterol levels were reduced and biliary levels were increased by CDCA and OCA and hepatic sterol transporters, abcg5/8, expression were increased by OCA. Both CDCA and OCA increased plasma FGF19 and OCA increased intestinal FGF19, FABP6, and SLC51A. Both CDCA and OCA increased intestinal mucosal growth, whereas CDCA increased the plasma GLP-2, GLP-1 and GIP.

CONCLUSIONS

Enteral OCA prevented cholestasis and phytosterolemia by increased hepatic bile acid and sterol transport via induction of hepatobiliary transporter FXR target genes and not by suppression of bile acid synthesis genes. We also showed an intestinal trophic action of OCA that demonstrates a dual clinical benefit of FXR agonism in the prevention of PNALD in piglets.

Fat malabsorption in short bowel syndrome: A review of pathophysiology and management

Fat malabsorption is central to the pathophysiology of short bowel syndrome (SBS). It occurs in patients with insufficient intestinal surface area and/or function to maintain metabolic and growth demands. Rapid intestinal transit and impaired bile acid recycling further contribute to fat malabsorption. A significant portion of patients require parenteral nutrition (PN) for their survival but may develop sepsis and liver dysfunction as a result. Despite advancements in the treatment of SBS, fat malabsorption remains a chronic issue for this vulnerable patient population. Peer-reviewed literature was assessed on the topic of fat malabsorption in SBS. Current management of patients with SBS involves dietary considerations, PN management, antidiarrheals, glucagon-like peptide 2 agonists, and multidisciplinary teams. Clinical trials have focused on improving intestinal fat absorption by facilitating fat digestion with pancreatic enzymes. Targeting fat malabsorption in SBS is a potential pathway to improving lifestyle and reducing morbidity and mortality in this rare disease.

A Medium-Chain Fatty Acid Analogue Prevents Intestinal Failure-Associated Liver Disease in Preterm Yorkshire Piglets

BACKGROUND & AIMS

At least 20%-30% of patients with intestinal failure receiving long-term parenteral nutrition will develop intestinal failure-associated liver disease (IFALD), for which there are few therapeutic options. SEFA-6179 is a first-in-class structurally engineered medium-chain fatty acid analogue that acts through GPR84, PPARα, and PPARγ agonism. We hypothesized that SEFA-6179 would prevent biochemical and histologic liver injury in a preterm piglet model of IFALD.

METHODS

Preterm Yorkshire piglets were delivered by cesarean section, and parenteral nutrition was provided for 14 days via implanted central venous catheters. Animals were treated with either medium-chain triglyceride vehicle control or SEFA-6179.

RESULTS

Compared to medium-chain triglyceride vehicle at day of life 15, SEFA-6179 prevented biochemical cholestasis (direct bilirubin: 1.9 vs <0.2 mg/dL, P = .01; total bilirubin: 2.7 vs 0.4 mg/dL, P = .02; gamma glutamyl transferase: 172 vs 30 U/L, P = .01). SEFA-6179 also prevented steatosis (45.6 vs 13.9 mg triglycerides/g liver tissue, P = .009), reduced bile duct proliferation (1.6% vs 0.5% area cytokeratin 7 positive, P = .009), and reduced fibrosis assessed by a masked pathologist (median Ishak score: 3 vs 1, P = 0.007). RNA sequencing of liver tissue demonstrated that SEFA-6179 broadly impacted inflammatory, metabolic, and fibrotic pathways, consistent with its in vitro receptor activity (GPR84/PPARα/PPARγ agonist).

CONCLUSIONS

In a preterm piglet model of IFALD, SEFA-6179 treatment prevented biochemical cholestasis and steatosis and reduced bile duct proliferation and fibrosis. SEFA-6179 is a promising first-in-class therapy for the prevention and treatment of IFALD that will be investigated in an upcoming phase II clinical trial.

Outcomes in preterm infants who received a lipid emulsion with fish oil: An observational study

BACKGROUND

100% soybean oil emulsions (SO100) are associated with poor docosahexaenoic acid (DHA) and arachidonic acid (ARA) status in extremely low birth weight (ELBW) infants. A multi-oil emulsion with 15% fish oil (FO15) contains more DHA and ARA than SO100. This study compares clinical outcomes, namely growth and fatty acids, in ELBW infants who received S0100 or FO15.

METHODS

This observational study included ELBW infants born between 2014 and 2019 who received SO100 or FO15 for >7 days. Gas chromatography/mass spectrometry was used to measure erythrocyte fatty acids.

RESULTS

The mean ± SD gestational age was 27 ± 3 and 26 ± 2 weeks for SO100 (n = 43) and FO15 (n = 43), respectively (P = 0.2). DHA (-0.3 ± 0.10% per week, P = 0.026, for FO15 vs -0.2 ± 0.05% per week, P < 0.001, for SO100) and ARA (-0.8 ± 0.21% per week for FO15 vs -0.9 ± 0.17% per week for SO100; P < 0.001 for both) declined in both groups with no difference between groups (P interaction > 0.7 for both). After controlling for days to reach full feeds, the mean difference in weight z score trajectories was similar (Est = -0.08; 95% CI, -0.82 to 0.04; P = 0.2), and SO100 was associated with a nonsignificant increased odds for cholestasis (odds ratio, 3.1; 95% CI, 0.96-10.2; P = 0.059). There was no difference in other clinical comorbidities.

CONCLUSIONS

In comparison with ELBW infants who received SO100, infants who received FO15 still demonstrated a decline in DHA and ARA. Growth and other clinical outcomes were unchanged.

Interrupting tumor necrosis factor-alpha signaling prevents parenteral nutrition-associated cholestasis in mice

BACKGROUND

We have recently reported a mouse model of PN-associated cholestasis (PNAC) in which combining intestinal inflammation and PN infusion results in cholestasis, hepatic macrophage activation, and transcriptional suppression of canalicular bile acid, bilirubin and sterol transporters Abcb11, Abcc2 and Abcg5/8. The aim of this study was to examine the role of TNFα in promoting PNAC in mice.

METHODS

First, recombinant TNFα was administered to mice as well as in hepatocyte cell culture. Second, Tnfr1/2KO or wild-type (WT) mice were exposed to dextran sulfate sodium (DSS) for 4 days followed by soy-oil lipid emulsion-based PN infusion through a central venous catheter for 14 days (DSS-PN). Finally, WT/DSS-PN mice were also infused with infliximab at 10 mg/kg on days 3 and 10 of PN. PNAC was defined by increased serum aspartate aminotransferase, alanine aminotransferase, total bile acids, and bilirubin.

RESULTS

Intraperitoneal injection of TNFα into WT mice or TNFα treatment of Huh7 hepatocarcinoma cells and primary mouse hepatocytes suppressed messenger RNA (mRNA) transcription of bile (Abcb11, Abcc2]) and sterol transporters (Abcg5/8) and their regulators Nr1h3 and Nr1h4. DSS-PN mice with PNAC had increased hepatic TNFα mRNA expression and significant reduction of mRNA expression of Abcb11, Abcc2, Abcg5/8, Nr1h3, and Nr1h4. In contrast, PNAC development was prevented and mRNA expression normalized in both Tnfr1/2KO /DSS-PN mice and DSS-PN mice treated with infliximab.

CONCLUSIONS

TNFα is a key mediator in the pathogenesis of PNAC through suppression of hepatocyte Abcb11, Abcc2, and Abcg5/8. Pharmacologic targeting of TNFα as a therapeutic strategy for PNAC thus deserves further investigation.

Lactobacillus plantarum supplementation alleviates liver and intestinal injury in parenteral nutrition-fed piglets

OBJECTIVE

Long-term parenteral nutrition (PN) causes parenteral nutrition-associated liver disease (PNALD) for which therapeutic approaches are limited. This study aimed to investigate the effects of Lactobacillus plantarum CGMCC 1258 (LP) on liver and intestinal injury in the PN-fed neonatal piglets.

METHODS

The piglets received PN with or without oral LP for 14 days. The levels of liver enzymes and inflammatory markers were measured using biochemical kits and q-RT-PCR. Serum fibroblast growth factor 19 (FGF19) was detected using an enzyme-linked immunosorbent assay (ELISA). The bile acid profiles in the liver, serum, and intestinal contents were determined using ultraperformance liquid chromatography coupled with mass spectrometry (UPLC-MS). The composition of intestinal bacteria was analyzed with 16S rRNA gene amplicon sequencing.

RESULTS

LP supplementation was associated with improved markers of liver disease, inflammation, and oxidative stress in PN-fed piglets. Moreover, markers of intestinal injury and inflammation were alleviated by LP in PN-fed piglets. Mechanistically, LP increased the abundance of Lactobacillus in ileal contents and stimulated FGF19 expression in ileal mucosa. Subsequently, it increased the expression of small heterodimer partner (SHP) and inhibited cholesterol 7α-hydroxylase (CYP7A1) expression in the liver. Additionally, LP altered the systemic composition and metabolism of bile acids.

CONCLUSIONS

LP alleviated liver and intestinal injury in PN-fed neonatal piglets by altering the composition of intestinal bacteria and bile acids. This article is protected by copyright. All rights reserved.

Maternal and Fetal Bile Acid Homeostasis Regulated by Sulfated Progesterone Metabolites through FXR Signaling Pathway in a Pregnant Sow Model

Abnormally elevated circulating bile acids (BA) during pregnancy endanger fetal survival and offspring health; however, the pathology and underlying mechanisms are poorly understood. A total of nineteen pregnant sows were randomly assigned to day 60 of gestation, day 90 of gestation (G60, G90), and the farrowing day (L0), to investigate the intercorrelation of reproductive hormone, including estradiol, progesterone and sulfated progesterone metabolites (PMSs), and BA in the peripheral blood of mother and fetuses during pregnancy. All data were analyzed by Student's t-test or one-way ANOVA of GraphPad Prism and further compared by using the Student-Newman-Keuls test. Correlation analysis was also carried out using the CORR procedure of SAS to study the relationship between PMSs and BA levels in both maternal and fetal serum at G60, G90, and L0. Allopregnanolone sulphate (PM4S) and epiallopregnanolone sulphate (PM5S) were firstly identified in the maternal and fetal peripheral blood of pregnant sows by using newly developed ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) methods. Correlation analysis showed that pregnancy-associated maternal BA homeostasis was correlated with maternal serum PM4S levels, whereas fetal BA homeostasis was correlated with fetal serum PM5S levels. The antagonist activity role of PM5S on farnesoid X receptor (FXR)-mediated BA homeostasis and fibroblast growth factor 19 (FGF19) were confirmed in the PM5S and FXR activator co-treated pig primary hepatocytes model, and the antagonist role of PM4S on FXR-mediated BA homeostasis and FGF19 were also identified in the PM4S-treated pig primary hepatocytes model. Together with the high relative expression of FGF19 in pig hepatocytes, the pregnant sow is a promising animal model to investigate the pathogenesis of cholestasis during pregnancy.

Suppression of Bile Acid Synthesis in a Preterm Infant Receiving Prolonged Parenteral Nutrition

Bile acid metabolism is altered in neonates on parenteral nutrition (PN), predisposing them to parenteral nutrition-associated liver disease. Cholesterol 7α-hydroxylase (CYP7A1), the rate-limiting enzyme in the bile acid synthesis pathway, is repressed by fibroblast growth factor 19 (FGF19) and phytosterols (PS). We describe a case of a preterm infant who developed necrotizing enterocolitis (NEC) and received exclusive PN for over 2 months. Our objective was to serially assess CYP7A1 activity and plasma FGF19 and PS concentrations in this infant case compared to five healthy preterm infants. We found that CYP7A1 activity increased during the first 2 weeks of life in control infants but was undetectable in the infant case. FGF19 concentrations were high at birth in all infants and subsequently declined and did not differ between the case and control infants. As expected, PS concentrations were elevated in the infant case and continued to increase despite lipid minimization. In conclusion, CYP7A1 activity was gradually upregulated in healthy preterm infants but remained suppressed in the infant requiring prolonged PN. Preterm infants also had elevated FGF19 concentrations at birth, which decreased with advancing postnatal age.

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.

NF-κB Regulation of LRH-1 and ABCG5/8 Potentiates Phytosterol Role in the Pathogenesis of Parenteral Nutrition-Associated Cholestasis

BACKGROUND AND AIMS

Chronically administered parenteral nutrition (PN) in patients with intestinal failure carries the risk for developing PN-associated cholestasis (PNAC). We have demonstrated that farnesoid X receptor (FXR) and liver X receptor (LXR), proinflammatory interleukin-1 beta (IL-1β), and infused phytosterols are important in murine PNAC pathogenesis. In this study we examined the role of nuclear receptor liver receptor homolog 1 (LRH-1) and phytosterols in PNAC.

APPROACH AND RESULTS

In a C57BL/6 PNAC mouse model (dextran sulfate sodium [DSS] pretreatment followed by 14 days of PN; DSS-PN), hepatic nuclear receptor subfamily 5, group A, member 2/LRH-1 mRNA, LRH-1 protein expression, and binding of LRH-1 at the Abcg5/8 and Cyp7a1 promoter was reduced. Interleukin-1 receptor-deficient mice (Il-1r^-/- /DSS-PN) were protected from PNAC and had significantly increased hepatic mRNA and protein expression of LRH-1. NF-κB activation and binding to the LRH-1 promoter were increased in DSS-PN PNAC mice and normalized in Il-1r^-/- /DSS-PN mice. Knockdown of NF-κB in IL-1β-exposed HepG2 cells increased expression of LRH-1 and ABCG5. Treatment of HepG2 cells and primary mouse hepatocytes with an LRH-1 inverse agonist, ML179, significantly reduced mRNA expression of FXR targets ATP binding cassette subfamily C member 2/multidrug resistance associated protein 2 (ABCC2/MRP2), nuclear receptor subfamily 0, groupB, member 2/small heterodimer partner (NR0B2/SHP), and ATP binding cassette subfamily B member 11/bile salt export pump (ABCB11/BSEP). Co-incubation with phytosterols further reduced expression of these genes. Similar results were obtained by suppressing the LRH-1 targets ABCG5/8 by treatment with small interfering RNA, IL-1β, or LXR antagonist GSK2033. Liquid chromatography-mass spectrometry and chromatin immunoprecipitation experiments in HepG2 cells showed that ATP binding cassette subfamily G member 5/8 (ABCG5/8) suppression by GSK2033 increased the accumulation of phytosterols and reduced binding of FXR to the SHP promoter. Finally, treatment with LRH-1 agonist, dilauroyl phosphatidylcholine (DLPC) protected DSS-PN mice from PNAC.

CONCLUSIONS

This study suggests that NF-κB regulation of LRH-1 and downstream genes may affect phytosterol-mediated antagonism of FXR signaling in the pathogenesis of PNAC. LRH-1 could be a potential therapeutic target for PNAC.

Fish oil-based lipid emulsion alleviates parenteral nutrition-associated liver diseases and intestinal injury in piglets

BACKGROUND

Thisstudy aimed to investigate the impact of fish oil-based lipid emulsion (FO) on enterohepatic injuries and intestinal microbiota in piglets of parenteral nutrition (PN).

METHODS

Newborn piglets were divided into three groups, including enteral diet (the controls), PN with 100% FO and PN with medium-chain triglyceride/long-chain triglyceride-based lipid emulsion (MCT/LCT) for 14 days. Serum biochemical indicators, hepatic and intestinal histology, and expression of genes associated with inflammation, oxidative stress, and lipid metabolism were measured. The bile acid (BA) profiles in serum and the taxonomic composition of the gut microbiome in different intestinal segments were analyzed.

RESULTS

Compared with MCT/LCT-piglets, FO reduced inflammation, promoted fatty acid oxidation, and decreased oxidative stress in the liver. In the intestine, FO decreased intestinal inflammation and intestinal permeability, leading to reduced lipopolysaccharide entry into the blood circulation relative to MCT/LCT-piglets. PN groups have dominant contents of Proteobacteria and Bacteroides, whereas the control group have Firmicutes at the phylum level. FO altered the taxonomic compositions of the gut microbiome in different segments, increased the relative abundance of Bacteroidaceae in ileum, and Rikenellaceae and Ruminococcaceae in the colon. FO treatment shifted BA composition ratio in serum and had a lower ratio of secondary BAs to primary BAs.

CONCLUSION

FO alleviates PNLAD and intestinal injury by regulating the homeostasis of BAs' enterohepatic circulation and altering microbiota composition in different intestinal segments.

The Farnesoid X Receptor Agonist Tropifexor Prevents Liver Damage in Parenteral Nutrition-fed Neonatal Piglets

OBJECTIVES

Intestinal failure-associated liver disease (IFALD) is a life-threatening complication for patients with intestinal failure who receive long-term parenteral nutrition (PN). We evaluated the effects of the farnesoid X receptor agonist tropifexor on a neonatal piglet model of IFALD fed with PN.

METHODS

The piglets received PN and tropifexor for 14 days, then levels of liver enzymes, bile acid metabolism, inflammation, and intestinal barrier markers were assessed using quantitative real-time PCR. Fibroblast growth factor (FGF) 19 serum levels were determined using enzyme-linked immunosorbent assays. Bile acids were determined in liver, serum, and intestinal contents, and the microbiome was sequenced in different intestinal segments.

RESULTS

The PN model was established in newborn piglets. The levels of serum liver enzymes, pro-inflammatory factors, and oxidative stress increased in the livers of piglets fed with PN, but not in those fed with PN and tropifexor. Tropifexor stimulated FGF19 expression in ileal epithelial cells, increased portal FGF19 levels, then inhibited cholesterol 7α-hydroxylase expression in the liver. Tropifexor increased the relative abundance of bacteria associated with bile salt hydrolase and 7α-dehydrogenation in the contents of ileum and altered the composition of bile acids in serum, liver, and intestinal contents. Tropifexor also inhibited intestinal inflammation, alleviated intestinal mucosal atrophy, and improved the intestinal barrier.

CONCLUSIONS

Tropifexor might prevent liver damage in neonatal piglets receiving PN by altering the composition of intestinal microbiota and bile acids. Tropifexor also alleviates intestinal inflammation and preserves the intestinal barrier.

Effects of Dietary n-3 and n-6 Polyunsaturated Fatty Acids in Inflammation and Cancerogenesis

The dietary recommendation encourages reducing saturated fatty acids (SFA) in diet and replacing them with polyunsaturated fatty acids (PUFAs) n-3 (omega-3) and n-6 (omega-6) to decrease the risk of metabolic disturbances. Consequently, excessive n-6 PUFAs content and high n-6/n-3 ratio are found in Western-type diet. The importance of a dietary n-6/n-3 ratio to prevent chronic diseases is linked with anti-inflammatory functions of linolenic acid (ALA, 18:3n-3) and longer-chain n-3 PUFAs. Thus, this review provides an overview of the role of oxylipins derived from n-3 PUFAs and oxylipins formed from n-6 PUFAs on inflammation. Evidence of PUFAs' role in carcinogenesis was also discussed. In vitro studies, animal cancer models and epidemiological studies demonstrate that these two PUFA groups have different effects on the cell growth, proliferation and progression of neoplastic lesions.

Impact of Parenteral Lipid Emulsion Components on Cholestatic Liver Disease in Neonates

Total parenteral nutrition (TPN) is a life-saving intervention for infants that are unable to feed by mouth. Infants that remain on TPN for extended periods of time are at risk for the development of liver injury in the form of parenteral nutrition associated cholestasis (PNAC). Current research suggests the lipid component of TPN is a factor in the development of PNAC. Most notably, the fatty acid composition, vitamin E concentration, and presence of phytosterols are believed key mediators of lipid emulsion driven PNAC development. New emulsions comprised of fish oil and medium chain triglycerides show promise for reducing the incidence of PNAC in infants. In this review we will cover the current clinical studies on the benefit of fish oil and medium chain triglyceride containing lipid emulsions on the development of PNAC, the current constituents of lipid emulsions that may modulate the prevalence of PNAC, and potential new supplements to TPN to further reduce the incidence of PNAC.

Parenteral Fish-Oil Containing Lipid Emulsions Limit Initial Lipopolysaccharide-Induced Host Immune Responses in Preterm Pigs

Multicomponent lipid emulsions are available for critical care of preterm infants. We sought to determine the impact of different lipid emulsions on early priming of the host and its response to an acute stimulus. Pigs delivered 7d preterm (n = 59) were randomized to receive different lipid emulsions for 11 days: 100% soybean oil (SO), mixed oil emulsion (SO, medium chain olive oil and fish oil) including 15% fish oil (MO15), or 100% fish oil (FO100). On day 11, pigs received an 8-h continuous intravenous infusion of either lipopolysaccharide (LPS—lyophilized Escherichia coli) or saline. Plasma was collected for fatty acid, oxylipin, metabolomic, and cytokine analyses. At day 11, plasma omega-3 fatty acid levels in the FO100 groups showed the highest increase in eicosapentaenoic acid, EPA (0.1 ± 0.0 to 9.7 ± 1.9, p < 0.001), docosahexaenoic acid, DHA (day 0 = 2.5 ± 0.7 to 13.6 ± 2.9, p < 0.001), EPA and DHA-derived oxylipins, and sphingomyelin metabolites. In the SO group, levels of cytokine IL1β increased at the first hour of LPS infusion (296.6 ± 308 pg/mL) but was undetectable in MO15, FO100, or in the animals receiving saline instead of LPS. Pigs in the SO group showed a significant increase in arachidonic acid (AA)-derived prostaglandins and thromboxanes in the first hour (p < 0.05). No significant changes in oxylipins were observed with either fish-oil containing group during LPS infusion. Host priming with soybean oil in the early postnatal period preserves a higher AA:DHA ratio and the ability to acutely respond to an external stimulus. In contrast, fish-oil containing lipid emulsions increase DHA, exacerbate a deficit in AA, and limit the initial LPS-induced inflammatory responses in preterm pigs.

Review of parenteral nutrition-associated liver disease

Parenteral nutrition has been widely used in patients whose gastrointestinal tract is anatomically or physiologically unavailable for sufficient food intake. It has been considered lifesaving but is not without adverse effects. It has been proven to cause liver injury through different mechanisms. We present a review of parenteral nutrition-associated liver disease.

Translational Advances in Pediatric Nutrition and Gastroenterology: New Insights from Pig Models

Pigs are increasingly important animals for modeling human pediatric nutrition and gastroenterology and complementing mechanistic studies in rodents. The comparative advantages in size and physiology of the neonatal pig have led to new translational and clinically relevant models of important diseases of the gastrointestinal tract and liver in premature infants. Studies in pigs have established the essential roles of prematurity, microbial colonization, and enteral nutrition in the pathogenesis of necrotizing enterocolitis. Studies in neonatal pigs have demonstrated the intestinal trophic effects of akey gut hormone, glucagon-like peptide 2 (GLP-2), and its role in the intestinal adaptation process and efficacy in the treatment of short bowel syndrome. Further, pigs have been instrumental in elucidating the physiology of parenteral nutrition-associated liver disease and the means by which phytosterols, fibroblast growth factor 19, and a new generation of lipid emulsions may modify disease. The premature pig will continue to be a valuable model in the development of optimal infant diets (donor human milk, colostrum), specific milk bioactives (arginine, growth factors), gut microbiota modifiers (pre-, pro-, and antibiotics), pharmaceutical drugs (GLP-2 analogs, FXR agonists), and novel diagnostic tools (near-infrared spectroscopy) to prevent and treat these pediatric diseases.

Phytosterolaemia associated with parenteral nutrition administration in adult patients

Vegetable lipid emulsions (LE) contain non-declared phytosterols (PS). We aimed to determine PS content depending on the brand and LE batch, and in adult hospitalised patients treated with parenteral nutrition (PN), to establish the association between plasma and administered PS. Part I was the LE study: totals and fractions of PS in three to four non-consecutive batches from six LE were analysed. Part II was the patient study: patients with at least 7 previous days of PN with 0·8 g/kg per d of an olive/soyabean (O/S) LE were randomised (day 0) 1:1 to O/S or 100 % fish oil (FO) at a dose of 0·4 g/kg per d for 7 d (day 7). Plasma PS, its fractions, total cholesterol on days 0 and 7, their clearance and their association with PS administered by LE were studied. In part I, LE study: differences were found in the total PS, their fractions and cholesterol among different LE brands and batches. Exclusive soyabean LE had the highest content of PS (422·36 (sd 130·46) μg/ml). In part II, patient study: nineteen patients were included. In the O/S group, PS levels were maintained (1·11 (sd 6·98) μg/ml) from day 0 to 7, while in the FO group, significant decreases were seen in total PS (-6·21 (sd 4·73) μg/ml) and their fractions, except for campesterol and stigmasterol. Plasma PS on day 7 were significantly associated with PS administered (R2 0·443). PS content in different LE brands had great variability. PS administered during PN resulted in accumulation and could be prevented with the exclusive administration of FO LE.

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.

New generation lipid emulsions increase brain DHA and improve body composition, but not short-term neurodevelopment in parenterally-fed preterm piglets

New generation, multicomponent parenteral lipid emulsions provide key fatty acids for brain growth and development, such as docosahexaenoic acid (DHA) and arachidonic acid (AA), yet the content may be suboptimal for preterm infants. Our aim was to test whether DHA and AA-enriched lipid emulsions would increase activity, growth, and neurodevelopment in preterm piglets and limit brain inflammation. Cesarean-delivered preterm pigs were given three weeks of either enteral preterm infant formula (ENT) or TPN with one of three parenteral lipid emulsions: Intralipid (IL), SMOFlipid (SMOF) or an experimental emulsion (EXP). Activity was continuously monitored and weekly blood sampling and behavioral field testing performed. At termination of the study, whole body and tissue metrics were collected. Neuronal density was assessed in sections of hippocampus (HC), thalamus, and cortex. Frontal cortex (FC) and HC tissue were assayed for fatty acid profiles and expression of genes of neuronal growth and inflammation. After 3 weeks of treatment, brain DHA content in SMOF, EXP and ENT pigs was higher (P < 0.01) in FC but not HC vs. IL pigs. There were no differences in brain weight or neuron density among treatment groups. Inflammatory cytokine TNFα and IL-1β expression in brain regions were increased in IL pigs (P < 0.05) compared to other groups. Overall growth velocity was similar among groups, but IL pigs had higher percent body fat and increased insulin resistance compared to other treatments (P < 0.05). ENT pigs spent more time in higher physical activity levels compared to all TPN groups, but there were no differences in exploratory behavior among groups. We conclude that a soybean oil emulsion increased select brain inflammatory cytokines and multicomponent lipid emulsions enriched with DHA and AA in parenteral lipids results in increased cortical DHA and improved body composition without affecting short term neurodevelopmental outcomes.

Effects of total parenteral nutrition on drug metabolism gene expression in mice

Parenteral nutrition-associated liver disease (PNALD) is a liver dysfunction caused by various risk factors presented in patients receiving total parenteral nutrition (TPN). Omega-6 rich Intralipid® and omega-3 rich Omegaven® are two intravenous lipid emulsions used in TPN. TPN could affect the hepatic expression of genes in anti-oxidative stress, but it's unknown whether TPN affects genes in drug metabolism. In this study, either Intralipid®- or Omegaven®-based TPN was administered to mice and the expression of a cohort of genes involved in anti-oxidative stress or drug metabolism was analyzed, glutathione (GSH) levels were measured, and protein levels for two key drug metabolism genes were determined. Overall, the expression of most genes was downregulated by Intralipid®-based TPN (Gstp1, Gstm1, 3, 6, Nqo1, Ho-1, Mt-1, Gclc, Gclm, Cyp2d9, 2f2, 2b10, and 3a11). Omegaven® showed similar results as Intralipid® except for preserving the expression of Gstm1 and Cyp3a11, and increasing Ho-1. Total GSH levels were decreased by Intralipid®, but increased by Omegaven®. CYP3A11 protein levels were increased by Omegaven®. In conclusion, TPN reduced the expression of many genes involved in anti-oxidative stress and drug metabolism in mice. However, Omegaven® preserved expression of Cyp3a11, suggesting another beneficial effect of Omegaven® in protecting liver functions.

Rifampicin, not vitamin E, suppresses parenteral nutrition-associated liver disease development through the pregnane X receptor pathway in piglets

Infants receiving long-term parenteral nutrition (PN) develop PN-associated liver disease (PNALD). We previously (Ng K et al. JPEN J Parenter Enteral Nutr 40: 656-671, 2016. doi:10.1177/0148607114567900.) showed that PN containing soy-based lipid supplemented with vitamin E (α-tocopherol) prevents the development of PNALD. We hypothesize that this occurs via vitamin E activation of pregnane X receptor (PXR)-mediated pathways involved in bile acid metabolism. Neonatal piglets received PN for 14 days containing Intralipid (IL; soy-based lipid emulsion), IL supplemented with 12.6 mg·kg^-1·day^-1 vitamin E (VITE), or IL with 10 mg·kg^-1·day^-1 Rifadin IV (RIF), a PXR agonist. Pigs treated with IL and VITE, but not RIF, developed cholestasis and hyperbilirubinemia, markers of liver disease. The hepatic PXR target genes CYP3A29 and UGT1A6 increased during RIF treatment. RIF also modestly increased metabolism of chenodeoxycholic acid to the more hydrophilic bile acid hyocholic acid. Serum fibroblast growth factor (FGF)-19, a key regulator in suppressing hepatic bile acid synthesis, significantly increased in the RIF group. We conclude rifampicin modified markers of PNALD development by increased metabolism of bile acids and potentially suppressed bile acid synthesis. Vitamin E was ineffective at high lipid doses in preventing PNALD.NEW & NOTEWORTHY Intravenous vitamin E and rifampicin were administered to neonatal piglets receiving parenteral nutrition to determine their efficacy in reducing the progression of parenteral nutrition-associated liver disease (PNALD). Rifampicin increased serum FGF-19 concentrations and synthesis of the bile acid hyocholic acid which led to a reduction of PNALD parameters at 2 wk of administration. This result has potential clinical implications for the use of rifampicin as a safe and inexpensive treatment for short-term development of PNALD.

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.

The effect of ω-3 polyunsaturated fatty acids on the liver lipidome, proteome and bile acid profile: parenteral versus enteral administration

Parenteral nutrition (PN) is often associated with the deterioration of liver functions (PNALD). Omega-3 polyunsaturated fatty acids (PUFA) were reported to alleviate PNALD but the underlying mechanisms have not been fully unraveled yet. Using omics´ approach, we determined serum and liver lipidome, liver proteome, and liver bile acid profile as well as markers of inflammation and oxidative stress in rats administered either ω-6 PUFA based lipid emulsion (Intralipid) or ω-6/ω-3 PUFA blend (Intralipid/Omegaven) via the enteral or parenteral route. In general, we found that enteral administration of both lipid emulsions has less impact on the liver than the parenteral route. Compared with parenterally administered Intralipid, PN administration of ω-3 PUFA was associated with 1. increased content of eicosapentaenoic (EPA)- and docosahexaenoic (DHA) acids-containing lipid species; 2. higher abundance of CYP4A isoenzymes capable of bioactive lipid synthesis and the increased content of their potential products (oxidized EPA and DHA); 3. downregulation of enzymes involved CYP450 drug metabolism what may represent an adaptive mechanism counteracting the potential negative effects (enhanced ROS production) of PUFA metabolism; 4. normalized anti-oxidative capacity and 5. physiological BAs spectrum. All these findings may contribute to the explanation of ω-3 PUFA protective effects in the context of PN.

Liver Inflammation Relates to Decreased Canalicular Bile Transporter Expression in Pediatric Onset Intestinal Failure

OBJECTIVE

Although liver disease is a major complication of parenteral nutrition (PN) for intestinal failure (IF), its pathogenesis remains unclear. We investigated potential molecular mechanisms of liver injury in pediatric onset IF.

METHODS

Liver expression of canalicular phospholipid (ABCB4), bile acid (ABCB11), and sterol (ABCG5/8) transporters, their upstream regulators LXR and FXR as well as pro-inflammatory cytokines interleukin-6 (IL6) and tumor necrosis factor (TNF) were investigated among patients with IF [age median 3.8 (IQR 1.2 to 11)] in relation to biochemical and histologic liver injury, PN, serum plant sterols, fibroblast growth factor 19, and α-tocopherol.

RESULTS

Patients receiving PN currently (n = 18) showed more advanced liver injury than patients after weaning off PN (n = 30). Histologic portal inflammation strongly segregated PN-dependent (44%) from weaned off patients (3%, P = 0.001) and coupled with progression of cholestasis and liver fibrosis. Patients with portal inflammation demonstrated markedly induced liver RNA expression of IL6 and TNF, repression of FXR and its canalicular bile transporter target gene RNA expression, including ABCB4 and ABCB11 as well as decreased protein expression of ABCB11 and ABCB4. Furthermore, upregulation of LXR and ABCG5/8 RNA expression was suppressed in patients with portal inflammation. Current PN, increased serum levels of plant sterols stigmasterol, avenasterol, and sitosterol along with serum citrulline, a marker of enterocyte mass, predicted portal inflammation.

CONCLUSIONS

In pediatric onset IF, current PN delivery synergistically with intestinal compromise promote liver inflammation, which associates with progression of biochemical and histologic liver injury, while reducing expression of canalicular bile transporters.

Effects of two different lipid emulsions on antioxidant status, lipid peroxidation and parenteral nutrition- related cholestasis in premature babies, a randomized-controlled study

BACKGROUND

Olive oil-soybean oil (OO/SO) based lipid emulsions (LE) lack ω-3 PUFAs eicosapentaenoic acid -EPA and docosahexaenoic acid- DHA, which have clinical benefits on inflammatory processes. Fish oil based LEs are good sources of DHA and EPA. Fish oil, MCT, Olive oil and Soya oil (FMOS) lipid is one of the fish oil containing LEs supplemented with high levels of α-tocopherol and lower levels of phytosterol compared to OO/SO lipid emulsions. We investigated the effects of OO/SO and FMOS lipid preparations on cholestasis, levels of antioxidant enzymes and lipid peroxidation.

METHODS

Preterm neonates ≤32 gestational weeks age and/or ≤1500 g were randomly assigned to receive either FMOS or OO/SO in the first day of life. Catalase, superoxide dismutase (SOD), glutathione peroxidase (GPx) and thiobarbituric acid reactive substances (TBARS) levels in the first day of life, 7th day of lipid use and 28th day of life were measured and cholestasis during parenteral nutrition was recorded.

RESULTS

34 and 33 patients were in FMOS and OO/SO lipid groups respectively. Although the TBARS levels were higher in the first day of life and 7^th day of LEs in OO/SO lipid group (p=0.014 and p=0.022), on the 28^th day of life TBARS level was similar and SOD level was higher (p=0.014) in OO/SO group. Cholestasis was significantly lower in FMOS lipid group (0% vs. 18.2%), (p=0.011) and neonates regained birth weight earlier (p=0.006). There was no significant difference in other morbidities.

CONCLUSIONS

FMOS and OO/SO lipid emulsions have similar effects on lipid peroxidation on 28th day of life and on morbidities in short term period except for cholestasis.

Targeted metabolomics analysis of maternal-placental-fetal metabolism in pregnant swine reveals links in fetal bile acid homeostasis and sulfation capacity

Cholestasis of pregnancy endangers fetal and neonatal survival, yet systematic knowledge of the cause and effect of disrupted bile acid (BA) homeostasis in pregnancy is limited. Here we show that gestation stage-associated BA dysregulation in swine correlated with fetal death resulting from compromised capacity for BA secretion and increased alternative systemic efflux. The balance of BA input and output in the developing uterus suggested little uptake and metabolism of maternal BA by the placenta-fetus unit, implying a protection role of placenta in preventing maternal BA transported into the fetus. We showed that the maternal origin of BA accounted for the increase in placental total BA, leading to dysregulated expression of genes involved in BA transport and potentially impaired transplacental export of fetus-derived BA. Correspondingly, the secondary BA, mainly derived from the mother, gradually decreased in the fetus. Finally, we identified that sulfation rather than glucuronidation played pivotal roles in maintaining BA homeostasis of the developing fetus. These novel and systemic findings contribute to a whole picture of BA metabolism in pregnancy and provide new insights into mechanisms responsible for maternal and fetal BA homeostasis. NEW & NOTEWORTHY We used a swine model to demonstrate the potentially impaired transplacental bile acid (BA) export, immaturity of fetal hepatic excretory function, and elevated BA synthesis in the developing fetus. Under these conditions, we have further identified that BA sulfation plays a pivotal role in regulation of fetal BA homeostasis, which appears to depend on the balance of BA synthesis and sulfation capacity. These novel findings have uncovered a previously unknown mechanism of BA homeostasis regulation in the developing fetus.

Mixed Lipid, Fish Oil, and Soybean Oil Parenteral Lipids Impact Cholestasis, Hepatic Phytosterol, and Lipid Composition

OBJECTIVES

In parenteral nutrition-dependent infants and children, intestinal failure (IF)-associated liver disease (IFALD) remains an important problem. A comparative study was undertaken of parenteral mixed lipid (ML), ω-3 predominant fish oil (FO), and ω-6 predominant soybean oil (SO) emulsions in regards to hepatic phytosterol, neutral lipid, fatty acid (FA) content, and the relationship to cholestasis in piglets.

METHODS

Neonatal piglets received parenteral nutrition, varying in lipid dose (5 or 10 g· kg · day) and formulation: SO5 (n = 5), SO10 (n = 5), FO5 (n = 5), and ML10 (n = 5). On day 14, liver chemistry, bile flow, histology and neutral lipid staining were assessed. Hepatic triglyceride FA content was determined using thin layer and gas chromatography, and phytosterol content was assessed using gas chromatography-mass spectrometry.

RESULTS

SO groups had higher prevalence of biochemical cholestasis (P < 0.04) and lower bile flow (P < 0.0001). Hepatic campesterol, stigmasterol, and β-sitosterol were highest in SO10 (P < 0.0001). Hepatic FA (P < 0.03) and ω-6/ω-3 FA ratio (P < 0.0001) were higher in the SO groups. Neutral lipid accumulation (P = 0.3) and liver histology (P = 0.16) were not different between groups. Univariate predictors of bile flow were: campesterol (r = -0.77, P = 0.001), β-sitosterol (r = -0.74, P = 0.002), stigmasterol (r = -0.74, P = 0.002), ω-6 FA (r = -0.72, P = 0.002), and ω-3 FA (r = 0.59, P = 0.02). Only campesterol independently predicted bile flow.

CONCLUSIONS

ML and FO lipid emulsions reduce cholestasis in association with lowered hepatic phytosterol and lipid content. Lower hepatic phytosterol and ω-6 FA content, and higher ω-3 FA content are hepatoprotective. Multivariate analysis suggests reduced phytosterol accumulation may best explain the hepatoprotective effect of fish oil-containing lipids.

The effects of two mixed intravenous lipid emulsions on clinical outcomes in infants after gastrointestinal surgery: a prospective, randomized study

BACKGROUND

There are many advantages of a SMOF emulsion (SMOF-lipid), such as liver-protective properties and anti-inflammatory effects. The objective of this study was to compare the clinical outcomes of SMOF-lipid with medium-chain triglycerides (MCT) /long-chain triglycerides (LCT) in infants after intestinal surgery.

METHODS

This was a prospective, randomized study. Neonates receiving intravenous nutrient solution, including lipid emulsion after gastrointestinal surgery, were included in this study. The patients were randomly assigned to the SMOF-lipid or MCT/LCT groups. Infants who received intravenous lipid emulsion continuously for > 2 weeks were considered to have completed the study. Differences in weight gain, nutrition indices, alanine transaminase (ALT), aspartate transaminase (AST), and direct bilirubin (DB), and inflammation cytokine markers (interleukin [IL]-6 and tumor necrosis factor [TNF]-α) were measured.

RESULTS

The final sample included 160 infants. One hundred fourteen infants received intravenous SMOF-lipid (74) or MCT/LCT (86) > 2 weeks and 46 infants received intravenous SMOF-lipid (22) or MCT/LCT (24) > 4 weeks. There were no significant differences in weight gain, nutrition indices, inflammation cytokine markers, and sepsis between the groups at the end of 2 and 4 weeks; however, in the SMOF group, the ALT, AST, and DB levels were significantly lower than the MCT/LCT group at the end of 4 weeks.

CONCLUSION

The mixture and balanced emulsion of SMOF-lipid was well-tolerated in infants who have undergone gastrointestinal surgery, and liver-protective properties were demonstrated following long-term venous nutrition, especially > 4 weeks.

Plant-based sterols and stanols in health & disease: "Consequences of human development in a plant-based environment?"

Dietary plant sterols and stanols as present in our diet and in functional foods are well-known for their inhibitory effects on intestinal cholesterol absorption, which translates into lower low-density lipoprotein cholesterol concentrations. However, emerging evidence suggests that plant sterols and stanols have numerous additional health effects, which are largely unnoticed in the current scientific literature. Therefore, in this review we pose the intriguing question "What would have occurred if plant sterols and stanols had been discovered and embraced by disciplines such as immunology, hepatology, pulmonology or gastroenterology before being positioned as cholesterol-lowering molecules?" What would then have been the main benefits and fields of application of plant sterols and stanols today? We here discuss potential effects ranging from its presence and function intrauterine and in breast milk towards a potential role in the development of non-alcoholic steatohepatitis (NASH), cardiovascular disease (CVD), inflammatory bowel diseases (IBD) and allergic asthma. Interestingly, effects clearly depend on the route of entrance as observed in intestinal-failure associated liver disease (IFALD) during parenteral nutrition regimens. It is only until recently that effects beyond lowering of cholesterol concentrations are being explored systematically. Thus, there is a clear need to understand the full health effects of plant sterols and stanols.

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.

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.

Impact of Clinical Use of Parenteral Lipid Emulsions on Bile Acid Metabolism and Composition in Neonatal Piglets

BACKGROUND

Neonates with intestinal failure dependent on parenteral nutrition (PN) are at risk of intestinal failure-associated liver disease (IFALD). PN lipid composition relates to the risk of IFALD, but the mechanisms are poorly understood. We investigated the effects of soybean oil (SO), a mixed-lipid (ML) emulsion containing fish oil (FO), and a pure FO. We hypothesized FO-containing PN lipids would result in increased gene expression of canalicular bile acid transporters and a larger, more hydrophilic bile acid pool, predictive of increased bile flow.

METHODS

Neonatal piglets were allocated to receive 1 of SO, ML, or FO throughout 14 days of PN feeding. Relative expression of genes involved in bile acid synthesis and transport were determined through quantitative polymerase chain reaction. Bile secreted from the liver was collected and measured. Bile acid composition was determined using tandem mass spectrometry. Regression analysis was used to determine predictors of bile flow.

RESULTS

PN reduced bile acid secretion (P < .001). FO-containing PN lipids were associated with greater expression of bile acid and organic solute transport genes (P < .05) and greater secretion of hydrophobic bile acids (P < .001). Farnesoid X receptor (P = .01), bile salt export pump (P < .01), multidrug resistant protein 2 (P < .01), and unconjugated hyocholic acid (P < .001) independently predicted bile flow.

CONCLUSIONS

PN lipid modulation altered bile acid metabolism and composition. These alterations may explain the hepatoprotective effects of FO-containing PN lipids and support their use in the prevention and treatment of IFALD.

A detailed guide to lipid therapy in intestinal failure

Intravenous lipid emulsions are an integral part of nutrition therapy in the intestinal failure patient. In addition to being a concentrated source of non-protein calories, they provide the essential fatty acids necessary for growth and development. Depending upon the oil source used in these products, complications such as intestinal failure associated liver disease (IFALD) can occur. This review will discuss the risks and benefits associated with these products, especially as they relate to the pediatric intestinal failure patient.

Aluminum Exposure from Parenteral Nutrition: Early Bile Canaliculus Changes of the Hepatocyte

Background: Neonates on long-term parenteral nutrition (PN) may develop parenteral nutrition-associated liver disease (PNALD). Aluminum (Al) is a known contaminant of infant PN, and we hypothesize that it substantially contributes to PNALD. In this study, we aim to assess the impact of Al on hepatocytes in a piglet model. Methods: We conducted a randomized control trial using a Yucatan piglet PN model. Piglets, aged 3–6 days, were placed into two groups. The high Al group (n = 8) received PN with 63 µg/kg/day of Al, while the low Al group (n = 7) received PN with 24 µg/kg/day of Al. Serum samples for total bile acids (TBA) were collected over two weeks, and liver tissue was obtained at the end of the experiment. Bile canaliculus morphometry were studied by transmission electron microscopy (TEM) and ImageJ software analysis. Results: The canalicular space was smaller and the microvilli were shorter in the high Al group than in the low Al group. There was no difference in the TBA between the groups. Conclusions: Al causes structural changes in the hepatocytes despite unaltered serum bile acids. High Al in PN is associated with short microvilli, which could decrease the functional excretion area of the hepatocytes and impair bile flow.

Macrophage-derived IL-1β/NF-κB signaling mediates parenteral nutrition-associated cholestasis

In infants intolerant of enteral feeding because of intestinal disease, parenteral nutrition may be associated with cholestasis, which can progress to end-stage liver disease. Here we show the function of hepatic macrophages and phytosterols in parenteral nutrition-associated cholestasis (PNAC) pathogenesis using a mouse model that recapitulates the human pathophysiology and combines intestinal injury with parenteral nutrition. We combine genetic, molecular, and pharmacological approaches to identify an essential function of hepatic macrophages and IL-1β in PNAC. Pharmacological antagonism of  IL-1 signaling or genetic deficiency in CCR2, caspase-1 and caspase-11, or IL-1 receptor (which binds both IL-1α and IL-1β) prevents PNAC in mice. IL-1β increases hepatocyte NF-κB signaling, which interferes with farnesoid X receptor and liver X receptor bonding to respective promoters of canalicular bile and sterol transporter genes (Abcc2, Abcb11, and Abcg5/8), resulting in transcriptional suppression and subsequent cholestasis. Thus, hepatic macrophages, IL-1β, or NF-κB may be targets for restoring bile and sterol transport to treat PNAC.

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

BACKGROUND

Intestinal failure-associated liver disease (IFALD) is complex and diagnosed by concurrent use of parenteral nutrition, clinical presentation, and alterations in hepatic biomarkers exclusive of other causes of liver disease. In comparison with individual measures, composite biomarkers may provide a more effective means for assessing disease progression and response to treatment than single parameters. Since IFALD is considered by some to be a type of drug-induced liver injury (DILI), those diagnostic criteria could potentially be used in this population. Using a preexisting database of children treated for IFALD, our aim was to determine if a similar composite biomarker could be applied to this population.

STUDY DESIGN

Adult DILI criteria were applied at baseline, when treatment for IFALD (ie, direct bilirubin ≥2.0 mg/dL) was initiated.

RESULTS

A total of 214 patients with IFALD treated at Boston Children's Hospital were identified; 168 patients were eligible for analysis. Most patients analyzed were male (61%) and preterm (87%). Alkaline phosphatase (ALP) ≥2× upper limit of normal (ULN) captured the least amount of DILI (11%), while γ-glutamyltransferase (GGT) ≥1× ULN accounted for the most (62%). Using adult DILI criteria, 60 (39%) patients with IFALD were found to have DILI. Substituting GGT ≥1× ULN for ALP ≥2× ULN improved the sensitivity, with 105 (69%) of patients meeting at least 1 criterion for DILI.

CONCLUSION

Numerous challenges made it difficult to apply the DILI criteria to children with IFALD. Direct bilirubin, fractionated ALP, and perhaps GGT may be more suitable. Given its complex etiology and the age-based differences due to hepatic immaturity and growth, a more suitable composite marker needs to be developed to assess IFALD in this population.

Parenteral Soybean Oil Induces Hepatosteatosis Despite Addition of Fish Oil in a Mouse Model of Intestinal Failure-Associated Liver Disease

BACKGROUND

Replacement of parenteral soybean oil (SO) with fish oil (FO) is an effective therapy for intestinal failure-associated liver disease (IFALD) in children. However, practitioners remain concerned about the risk of essential fatty acid deficiency (EFAD) and sometimes treat IFALD with a combination of 50% SO and 50% FO emulsions. The purpose of this study was to determine if mixing 50% SO and 50% FO emulsions would prevent hepatosteatosis in a murine model of parenteral nutrition (PN)-induced hepatosteatosis.

METHODS

C57BL/6 mice were randomized to receive oral PN with parenteral saline, FO, SO, or a mixture of 50% FO and 50% SO for 19 days. Fatty acid analysis, histologic evaluation, Nonalcoholic Steatohepatitis Clinical Research Network (NSCRN) scores, and reverse-transcriptase polymerase chain reaction for key lipogenic genes were performed.

RESULTS

The PN + saline group was the only group with EFAD, with a serum and hepatic triene/tetraene ratio of 0.53. NSCRN scores were highest in the PN + SO group (5.5; 95% confidence interval [CI], 4.9-6.1), followed by the PN + FO/SO (4.5; 95% CI, 3.5-5.5) group, with the lowest score in the PN + FO (2.0; 95% CI, 1.1-2.9) group. Acetyl CoA carboxylase α and acetyl CoA carboxylase β expression was lower in the PN + FO group than in the PN + FO/SO or PN + SO groups.

CONCLUSIONS

Our data demonstrate that a mixed fat emulsion of 50% SO and 50% FO is inferior to 100% FO in reducing hepatosteatosis in this model. These data suggest that use of parenteral SO with parenteral FO, in a 1:1 ratio, may still contribute to liver injury, although it is less hepatotoxic than pure SO.

Phytosterols Synergize With Endotoxin to Augment Inflammation in Kupffer Cells but Alone Have Limited Direct Effect on Hepatocytes

INTRODUCTION

Phytosterols are implicated in the development of parenteral nutrition-associated liver disease. A newly proposed mechanism for phytosterol-mediated parenteral nutrition-associated liver disease is through phytosterol-facilitated hepatic proinflammatory cytokine release following exposure to intestinally derived bacteria. Whether the proinflammatory effects are liver cell specific is not known.

AIM

To determine if phytosterols cause inflammation in hepatocytes or Kupffer cells independently or require costimulation by lipopolysaccharide (LPS).

METHODS

In an in vivo study, neonatal piglets on parenteral nutrition for 11 days received an 8-hour infusion of LPS. In the in vitro studies, neonatal piglet Kupffer cells and hepatocytes were treated with media, media + 1% soy oil, or media + 1% soy oil + 100µM phytosterols. After 24-hour incubation, cells were treated with farnesoid X receptor (FXR) agonist obeticholic acid or liver X receptor (LXR) agonist GW3965 and challenged with LPS or interleukin 1β.

RESULTS

LPS administration in piglets led to transient increases in proinflammatory cytokines and suppression of the transporters bile salt export pump and ATP-binding cassette transporter G5. In hepatocytes, phytosterols did not activate inflammation. Phytosterol treatment alone did not activate inflammation in Kupffer cells but, combined with LPS, synergistically increased interleukin 1β production. FXR and LXR agonists increased transporter expression in hepatocytes. GW3965 suppressed proinflammatory cytokine production in Kupffer cells, but obeticholic acid did not.

CONCLUSIONS

LPS suppresses transporters that control bile acid and phytosterol clearance. Phytosterols alone do not cause inflammatory response. However, with costimulation by LPS, phytosterols synergistically maximize the inflammatory response in Kupffer cells.

Parenteral nutrition dysregulates bile salt homeostasis in a rat model of parenteral nutrition-associated liver disease

BACKGROUND & AIMS

Parenteral nutrition (PN), a lifesaving therapy in patients with intestinal failure, has been associated with hepatobiliary complications including steatosis, cholestasis and fibrosis, collectively known as parenteral nutrition-associated liver disease (PNALD). To date, the pathogenesis of PNALD is poorly understood and therapeutic options are limited. Impaired bile salt homeostasis has been proposed to contribute PNALD. The objective of this study was to establish a PNALD model in rats and to evaluate the effects of continuous parenteral nutrition (PN) on bile salt homeostasis.

METHODS

Rats received either PN via the jugular vein or received normal diet for 3, 7 or 14 days. Serum biochemistry, hepatic triglycerides, circulating bile salts and C4, IL-6 and TNF-alpha, and lipogenic and bile salt homeostatic gene expression in liver and ileum were assessed.

RESULTS

PN increased hepatic triglycerides already after 3 days of administration, and resulted in conjugated bilirubin elevation after 7 or more days. This indicates PN-induced steatosis and impaired canalicular secretion of bilirubin, the latter which is in line with reduced hepatic expression of Mrp2 mRNA. There was no histological evidence for liver inflammation after PN administration, and circulating levels of pro-inflammatory cytokines IL-6 and TNF-α, were comparable in all groups. Hepatic expression of Fxr mRNA was decreased after 7 days of PN, without apparent effect on expression of Fxr targets Bsep and Shp. Nonetheless, Cyp7a1 expression was reduced after 7 days of PN, indicative for lowered bile salt synthesis. Circulating levels of C4 (marker of bile salt synthesis) were also decreased after 3, 7 and 14 days of PN. Levels of circulating bile salts were not affected by PN.

CONCLUSIONS

This study showed that PN in rats caused early mild steatosis and cholestasis, while hepatic and systemic inflammation were not present. The onset of these abnormalities was associated with alterations in bile salt synthesis and transport. This animal model serves as an experimental model to further investigate the pathogenesis of PNALD inflicted by steatosis and cholestasis.

Management of Parenteral Nutrition in Hospitalized Adult Patients [Formula: see text]

Despite the high prevalence of malnutrition in adult hospitalized patients, surveys continue to report that many clinicians are undertrained in clinical nutrition, making targeted nutrition education for clinicians essential for best patient care. Clinical practice models also continue to evolve, with more disciplines prescribing parenteral nutrition (PN) or managing the cases of patients who are receiving it, further adding to the need for proficiency in general PN skills. This tutorial focuses on the daily management of adult hospitalized patients already receiving PN and reviews the following topics: (1) PN basics, including the determination of energy and volume requirements; (2) PN macronutrient content (protein, dextrose, and intravenous fat emulsion); (3) PN micronutrient content (electrolytes, minerals, vitamins, and trace elements); (4) alteration of PN for special situations, such as obesity, hyperglycemia, hypertriglyceridemia, refeeding, and hepatic/renal disease; (5) daily monitoring and adjustment of PN formula; and (6) PN-related complications (PN-associated liver disease and catheter-related complications).

Multi-omic profiles of hepatic metabolism in TPN-fed preterm pigs administered new generation lipid emulsions

We aimed to characterize the lipidomic, metabolomic, and transcriptomic profiles in preterm piglets administered enteral (ENT) formula or three parenteral lipid emulsions [parenteral nutrition (PN)], Intralipid (IL), Omegaven (OV), or SMOFlipid (SL), for 14 days. Piglets in all parenteral lipid groups showed differential organ growth versus ENT piglets; whole body growth rate was lowest in IL piglets, yet there were no differences in either energy expenditure or (13)C-palmitate oxidation. Plasma homeostatic model assessment of insulin resistance demonstrated insulin resistance in IL, but not OV or SL, compared with ENT. The fatty acid and acyl-CoA content of the liver, muscle, brain, and plasma fatty acids reflected the composition of the dietary lipids administered. Free carnitine and acylcarnitine (ACT) levels were markedly reduced in the PN groups compared with ENT piglets. Genes associated with oxidative stress and inflammation were increased, whereas those associated with alternative pathways of fatty acid oxidation were decreased in all PN groups. Our results show that new generation lipid emulsions directly enrich tissue fatty acids, especially in the brain, and lead to improved growth and insulin sensitivity compared with a soybean lipid emulsion. In all total PN groups, carnitine levels are limiting to the formation of ACTs and gene expression reflects the stress of excess lipid on liver function.

ESPGHAN Committee on Nutrition Position Paper. Intravenous Lipid Emulsions and Risk of Hepatotoxicity in Infants and Children: a Systematic Review and Meta-analysis

The aim of the present article was to perform a systematic review with meta-analysis of available scientific evidence regarding the role of different intravenous lipid emulsions (ILE) in the pathogenesis of cholestasis and parenteral nutrition-associated liver disease. A systematic review of the literature (up to March 2015) identified 23 randomized controlled trials (RCTs). Of these, 17 were performed in preterm infants or critically ill neonates with a short duration of intervention, 2 in older children with short-term use (following surgery or bone marrow transplantation), 1 in neonates with long-term use, and 3 in infants and children receiving long-term parenteral nutrition (PN). Meta-analysis showed no differences in the rate of cholestasis or bilirubin levels associated with short-term use of different ILEs. Because of high heterogeneity of the long-term studies no meta-analysis could be performed. Available studies found that the use of multicomponent fish oil (FO)-containing ILE compared with pure soya bean oil (SO), ILE-reduced liver enzymes, and bilirubin levels in noncholestatic children on long-term PN and one other RCT found that FO-based ILE-reversed cholestasis in a proportion of patients. The ESPGHAN Committee on Nutrition concludes that there is no evidence of a difference in rates of cholestasis or bilirubin levels between different ILE for short-term use in neonates. The use of multicomponent FO-containing ILE may contribute to a decrease in total bilirubin levels in children with IF on prolonged PN. Well-designed RCTs are, however, lacking and long-term effects have not been determined.