Prediction, identification and progression of histopathological liver disease activity in children with intestinal failure

Major surgical conditions of childhood and their lifelong implications: comprehensive review

BACKGROUND

In recent decades, the survival of children with congenital anomalies and paediatric cancer has improved dramatically such that there has been a steady shift towards understanding their lifelong health outcomes. Paediatric surgeons will actively manage such conditions in childhood and adolescence, however, adult surgeons must later care for these 'grown-ups' in adulthood. This article aims to highlight some of those rare disorders encountered by paediatric surgeons requiring long-term follow-up, their management in childhood and their survivorship impact, in order that the adult specialist may be better equipped with skills and knowledge to manage these patients into adulthood.

METHODS

A comprehensive literature review was performed to identify relevant publications. Research studies, review articles and guidelines were sought, focusing on the paediatric management and long-term outcomes of surgical conditions of childhood. The article has been written for adult surgeon readership.

RESULTS

This article describes the aforementioned conditions, their management in childhood and their lifelong implications, including: oesophageal atresia, tracheo-oesophageal fistula, malrotation, short bowel syndrome, duodenal atresia, gastroschisis, exomphalos, choledochal malformations, biliary atresia, Hirschsprung disease, anorectal malformations, congenital diaphragmatic hernia, congenital lung lesions and paediatric cancer.

CONCLUSION

The increasing survivorship of children affected by surgical conditions will translate into a growing population of adults with lifelong conditions and specialist healthcare needs. The importance of transition from childhood to adulthood is becoming realized. It is hoped that this timely review will enthuse the readership to offer care for such vulnerable patients, and to collaborate with paediatric surgeons in providing successful and seamless transitional care.

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.

Inflammation drives pathogenesis of early intestinal failure-associated liver disease

Patients with intestinal failure who receive long-term parenteral nutrition (PN) often develop intestinal failure-associated liver disease (IFALD). Although there are identified risk factors, the early pathogenesis is poorly understood and treatment options are limited. Here, we perform a transcriptomic analysis of liver tissue in a large animal IFALD model to generate mechanistic insights and identify therapeutic targets. Preterm Yorkshire piglets were provided PN or bottle-fed with sow-milk replacer for 14 days. Compared to bottle-fed controls, piglets receiving PN developed biochemical cholestasis by day of life 15 (total bilirubin 0.2 vs. 2.9 mg/dL, P = 0.01). RNA-Seq of liver tissue was performed. Ingenuity Pathway Analysis identified 747 differentially expressed genes (343 upregulated and 404 downregulated) with an adjusted P < 0.05 and a fold-change of > |1|. Enriched canonical pathways were identified, demonstrating broad activation of inflammatory pathways and inhibition of cell cycle progression. Potential therapeutics including infliximab, glucocorticoids, statins, and obeticholic acid were identified as predicted upstream master regulators that may reverse the PN-induced gene dysregulation. The early driver of IFALD in neonates may be inflammation with an immature liver; identified therapeutics that target the inflammatory response in the liver should be investigated as potential treatments.

Metabolic and Nutritional Issues after Lower Digestive Tract Surgery: The Important Role of the Dietitian in a Multidisciplinary Setting

Many patients undergo small bowel and colon surgery for reasons related to malignancy, inflammatory bowel disease (IBD), mesenteric ischemia, and other benign conditions, including post-operative adhesions, hernias, trauma, volvulus, or diverticula. Some patients arrive in the operating theatre severely malnourished due to an underlying disease, while others develop complications (e.g., anastomotic leaks, abscesses, or strictures) that induce a systemic inflammatory response that can increase their energy and protein requirements. Finally, anatomical and functional changes resulting from surgery can affect either nutritional status due to malabsorption or nutritional support (NS) pathways. The dietitian providing NS to these patients needs to understand the pathophysiology underlying these sequelae and collaborate with other professionals, including surgeons, internists, nurses, and pharmacists. The aim of this review is to provide an overview of the nutritional and metabolic consequences of different types of lower gastrointestinal surgery and the role of the dietitian in providing comprehensive patient care. This article reviews the effects of small bowel resection on macronutrient and micronutrient absorption, the effects of colectomies (e.g., ileocolectomy, low anterior resection, abdominoperineal resection, and proctocolectomy) that require special dietary considerations, nutritional considerations specific to ostomized patients, and clinical practice guidelines for caregivers of patients who have undergone a surgery for local and systemic complications of IBD. Finally, we highlight the valuable contribution of the dietitian in the challenging management of short bowel syndrome and intestinal failure.

A medium-chain fatty acid analogue prevents hepatosteatosis and decreases inflammatory lipid metabolites in a murine model of parenteral nutrition-induced hepatosteatosis

BACKGROUND

Parenteral (intravenous) nutrition is lifesaving for patients with intestinal failure, but long-term use of parenteral nutrition often leads to liver disease. SEFA-6179 is a synthetic medium-chain fatty acid analogue designed to target multiple fatty acid receptors regulating metabolic and inflammatory pathways. We hypothesized that SEFA-6179 would prevent hepatosteatosis and lipotoxicity in a murine model of parenteral nutrition-induced hepatosteatosis.

METHODS

Two in vivo experiments were conducted. In the first experiment, six-week-old male mice were provided an ad lib fat-free high carbohydrate diet (HCD) for 19 days with orogastric gavage of either fish oil, medium-chain triglycerides, or SEFA-6179 at a low (0.3mmol/kg) or high dose (0.6mmol/kg). In the second experiment, six-week-old mice were provided an ad lib fat-free high carbohydrate diet for 19 days with every other day tail vein injection of saline, soybean oil lipid emulsion, or fish oil lipid emulsion. Mice then received every other day orogastric gavage of medium-chain triglyceride vehicle or SEFA-6179 (0.6mmol/kg). Hepatosteatosis was assessed by a blinded pathologist using an established rodent steatosis score. Hepatic lipid metabolites were assessed using ultra-high-performance liquid chromatography-mass spectrometry. Effects of SEFA-6179 on fatty acid oxidation, lipogenesis, and fatty acid uptake in human liver cells were assessed in vitro.

RESULTS

In the first experiment, mice receiving the HCD with either saline or medium-chain triglyceride treatment developed macrovesicular steatosis, while mice receiving fish oil or SEFA-6179 retained normal liver histology. In the second experiment, mice receiving a high carbohydrate diet with intravenous saline or soybean oil lipid emulsion, along with medium chain triglyceride vehicle treatment, developed macrovescular steatosis. Treatment with SEFA-6179 prevented steatosis. In each experiment, SEFA-6179 treatment decreased arachidonic acid metabolites as well as key molecules (diacylglycerol, ceramides) involved in lipotoxicity. SEFA-6179 increased both β- and complete fatty oxidation in human liver cells, while having no impact on lipogenesis or fatty acid uptake.

CONCLUSIONS

SEFA-6179 treatment prevented hepatosteatosis and decreased toxic lipid metabolites in a murine model of parenteral nutrition-induced hepatosteatosis. An increase in both β- and complete hepatic fatty acid oxidation may underlie the reduction in steatosis.

Featuring molecular regulation of bile acid homeostasis in pediatric short bowel syndrome

BACKGROUND

Disturbed bile acid homeostasis may foster development of short bowel syndrome (SBS) associated liver disease during and after weaning off parenteral nutrition (PN). Our aim was to study hepatic molecular regulation of bile acid homeostasis in relation to serum and fecal bile acid profiles in pediatric SBS.

METHODS

Liver histopathology and mRNA expression of genes regulating synthesis, uptake and export of bile acids, and cellular receptors involved in bile acid signaling were measured in SBS patients (n = 33, median age 3.2 years). Simultaneously, serum (n = 24) and fecal (n = 10) bile acid profiles were assessed. Sixteen patients were currently on PN. Results of patients were compared to healthy control subjects.

RESULTS

Nine of ten (90 %) patients with histological cholestasis received current PN, while portal inflammation was present in 60 % (6/10) of patients with cholestasis compared to 13 % (3/23) without cholestasis (P = 0.01). In all SBS patients, hepatic synthesis and uptake of bile acids was increased. Patients on current PN showed widespread repression of hepatic FXR target genes, including downregulated canalicular (BSEP, MDR3) and basolateral (MRP3) bile acid exporters. Serum and fecal primary bile acids were increased both during and after weaning off PN.

CONCLUSIONS

Bile acid homeostasis in SBS is characterized by interrupted enterohepatic circulation promoting increased hepatic synthesis and conservation of bile acids. In PN dependent SBS patients with hepatic cholestasis and inflammation, the molecular fingerprint of downregulated hepatocyte canalicular and basolateral bile acid export with simultaneously increased synthesis and uptake of bile acids could favor their accumulation in hepatocytes and predispose to liver disease.

Absorption of an engineered medium-chain fatty acid analogue in two short bowel syndrome minipig models

BACKGROUND

Enteral drug therapy is challenging in short bowel syndrome with intestinal failure (SBS-IF) because of unpredictable absorption. SEFA-6179 is an enterally administered medium-chain fatty acid analogue under development for intestinal failure-associated liver disease. We investigate the pharmacokinetics of two SEFA-6179 formulations in two large-animal models of SBS-IF, including a new pseudojejunostomy model.

METHODS

Twenty Yucatan minipigs were obtained. Half underwent pre-resection pharmacokinetic study with single-dose SEFA-6179 administration. All minipigs then underwent 90% jejunoileal resection, with either a jejunoileal anastomosis or bypass of the intraperitoneal colon with anastomosis just proximal to the rectum (pseudojejunostomy). On postoperative day 3, a single-dose pharmacokinetic study was performed.

RESULTS

Both SBS-IF models were well tolerated. Compared with the jejunoileal anastomosis minipigs, pseudojejunostomy minipigs had a more severe malabsorptive phenotype with weight loss by postoperative day 4 (+0.1 vs -0.9 kg, P = 0.03) and liquid diarrhea (Bristol 5 vs Bristol 7, P = 0.0007). Compared with pre-resection minipigs, both jejunoileal and pseudojejunostomy minipigs had lower total plasma exposure of SEFA-6179 measured by area under the curve (jejunoileal: 37% less, P = 0.049; pseudojejunostomy: 74% less, P = 0.0001). Peak plasma concentration was also lower in the pseudojejunostomy group compared with pre-resection (65% less, P = 0.04), but not lower in the jejunoileal group (P = 0.47).

CONCLUSION

In two SBS-IF minipig models, SEFA-6179 had substantially decreased absorption compared with pre-resection minipigs. Dose optimization for different intestinal anatomy and function may be required. We describe a new SBS-IF pseudojejunostomy model that may improve the translation of preclinical research to patients with SBS-IF who have enterostomies.

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.

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.

A nordic multicenter study on contemporary outcomes of pediatric short bowel syndrome in 208 patients

BACKGROUND & AIMS

Despite advances in the management of short bowel syndrome related intestinal failure (SBS-IF), large-scale contemporary pediatric studies are scarce. The aim of this multicenter study was to assess key outcomes and clinical prognostic factors in a recent Nordic pediatric SBS-IF population.

METHODS

Patients with SBS-IF treated during 2010-2019, whose parenteral support (PS) started at age <1 year and continued >60 consecutive days were included and retrospectively reviewed. All six participating centers followed multidisciplinary SBS-IF management. Risk factors for PS dependency, intestinal failure associated liver disease (IFALD) and mortality were assessed with Cox regression and Kaplan Meier analyses. IFALD was defined with serum liver biochemistry levels.

RESULTS

Among 208 patients, SBS-IF resulted from NEC in 49%, gastroschisis w/wo atresia in 14%, small bowel atresia in 12%, volvulus in 11%, and other diagnoses in 14%. Median age-adjusted small bowel length was 43% (IQR 21-80%). After median follow up of 4.4 years (IQR 2.5-6.9), enteral autonomy was reached by 76%, none had undergone intestinal transplantation, and overall survival was 96%. Half of deaths (4/8) were caused by septic complications. Although biochemical cholestasis occurred only in 3% at latest follow-up and none of deaths were directly caused by IFALD, elevated liver biochemistry (HR 0.136; P = 0.017) and shorter remaining small bowel (HR 0.941; P = 0.040) predicted mortality. Shorter remaining small bowel and colon, and presence of end-ostomy were the main predictors of PS dependency, but not IFALD. Patients with NEC reached enteral autonomy more efficiently and had decreased incidence of IFALD compared to other etiologies.

CONCLUSIONS

Although with current multidisciplinary management, prognosis of pediatric SBS is encouraging, septic complications and IFALD still associated with the remaining low mortality rate.

Hepatic dysfunction in patients receiving intravenous lipid emulsions

PURPOSE

Until recently, intravenous lipid emulsions (ILEs) have consisted of soybean oil (SO) only. This review addresses recent developments in the field, including the problem of intestinal failure associated liver disease (IFALD) that can occur with the use of ILEs in children and adults, and newer ILEs that may minimize and reverse IFALD.

RECENT FINDINGS

Cholestasis is the primary manifestation of IFALD in premature infants receiving ILEs, whereas in older children and adults, steatosis is predominant. Two alternative ILEs have been extensively investigated for both safety and efficacy. SMOF, an ILE containing medium chain triglyceride, soybean oil, olive oil and fish oil (FO), is now widely used in both children and adults. A newer FO ILE is approved for use in children only. However, in case reports FO ILE has been shown to improve IFALD in adults. A number of new studies suggest that cholestasis from ILEs is dose-related. IFALD does not improve in many patients after transition from SO to SMOF, but partial or complete replacement with FO can halt and reverse IFALD.

SUMMARY

Adverse hepatic effects from ILEs are to some extent dose-related. Overfeeding with fat or with carbohydrate, or simply providing excessive calories in general, may be responsible. More research is needed investigating dose-related effects of macronutrients on liver injury.

Use of a combined transient elastography and biochemical strategy to determine liver fibrosis in pediatric intestinal failure

BACKGROUND & AIMS

Non-invasive monitoring of intestinal failure (IF) associated liver disease is an ongoing challenge in children with IF. Our objective was to develop a combined algorithm of clinical, transient elastography (TE) and biochemical parameters to identify liver fibrosis in this population.

METHODS

A retrospective cohort study of IF patients followed by our intestinal rehabilitation program between November 2015 to October 2019. Patients with a liver biopsy and TE were included. Demographic and liver function tests were collected. Fibrosis on liver biopsies was graded using the modified Scheuer score. Decision tree based algorithms classified low (F0-F1) versus high (F2-F4) fibrosis scores based on a combination of TE, biochemical and demographic parameters, using 6-fold classification error, sensitivity and specificity cross-validation (CV) scores.

RESULTS

42 patients (74% male, median age 7.6 (4.6; 42.7) months) were evaluated. Median length of PN therapy was 182 (121; 556) days. High fibrosis was present in 40.5% with a median TE of 12.1 (6.7; 12.9) kPa in high fibrosis children. An algorithm, based on cut-off values for TE of 11.3 kPa and AST of 40 U/L, and grouping of the underlying etiology resulted in a correct classification of 88.1% of the pathology scores; with sensitivity 0.82 (95% CI 0.57; 0.96), specificity 0.92 (95% CI 0.74; 0.99), positive predictive value 0.88 (95% CI 0.64; 0.96) and negative predictive value 0.88 (95% CI 0.73; 0.96). The CV classification error was 28.6%, CV sensitivity 72.2% and CV specificity 75.5%.

CONCLUSIONS

This algorithm shows promising results that could simplify non-invasive monitoring of liver fibrosis in children with IF. Validation in additional IF cohorts is needed.

Down regulation of NDUFS1 is involved in the progression of parenteral-nutrition-associated liver disease by increasing Oxidative stress

Parenteral nutrition (PN)-associated liver disease (PNALD) is a common and life-threatening complication of patients receiving PN. However, its definitive pathology remains unclear. Ubiquinone oxidoreductase core subunit S1 (NDUFS1), which is the largest core subunit of mitochondrial complex I, could alter the mitochondrial reactive oxygen species (ROS) formation. The purpose of this study was to investigate the role of NDUFS1 in the pathogenesis of PNALD and its underlying mechanism. We performed hepatic proteomics analysis of PNALD patients, and established a PNALD rat model to verify the role of oxidative stress, NDUFS1, pyrin inflammasome, and IL-1β in the progression of PNALD. Proteomics analysis revealed the NDUFS1 expression was decreased in PNALD patients, and the differentially espressed proteins were involved in mitochondrial respiratory chain complex Ⅰ. Treatment with MitoQ or overexpression of NDUFS1 can alleviate the progression of PNALD by reducing oxidative stress. The expression of pyrin, caspase-1, and IL-1β was increased in PN rats. Pharmacological antagonism of pyrin by colchicine can alleviate liver injury and hepatic steatosis. NDUFS1 prevents PNALD pathogenesis by regulating oxidative stress. Pyrin inflammasome and IL-1β may participate in the process of PNALD development by suppressing the transcription of MTTP and impairing the secretion of VLDL. Oxidative stress reduction may be employed as a strategy in the prevention and treatment of PNALD.

Histopathological liver steatosis linked with high parenteral glucose and amino acid supply in infants with short bowel syndrome

BACKGROUND

Steatosis is a common feature of intestinal failure-associated liver disease (IFALD) in adult and older pediatric patients receiving long-term parenteral nutrition (PN). There are limited clinical data concerning steatosis in infants with short bowel syndrome (SBS). We investigated early histopathological steatosis and its association to PN.

METHODS

In this retrospective study, 31 patients with SBS had a diagnostic liver biopsy taken at the median age of 5 (IQR 3-8) months. Follow-up biopsy was available for 24 patients at the median age of 29 (IQR 14-52) months. We evaluated the biopsies for steatosis and other histopathological signs of IFALD and compared results with patient characteristics, PN composition, and liver biochemistry.

RESULTS

Diagnostic biopsies revealed steatosis in 8 (26%) patients. At the age of 3 months, patients with steatosis had received higher amounts of parenteral glucose: median 15.1 (IQR 12.4-17.2) vs 12.3 (8.7-14.4) g/kg/d (P = 0.04), amino acids: 2.9 (2.5-3.4) vs 2.2 (1.6-2.7) g/kg/d (P = 0.03), and energy: 87 (80-98) vs 73 (54-79) kcal/kg/d (P = 0.01) than those without steatosis. We detected no significant differences in parenteral lipid intake between the groups. Steatosis also associated with increased serum bile acid (P = 0.02), alanine aminotransferase (P = 0.0002), and aspartate aminotransferase (P = 0.001) levels.

CONCLUSIONS

In this cohort, high parenteral glucose, amino acid, and energy provision associated with liver steatosis in infants with SBS. We recommend monitoring of bile acid and transaminase levels while aiming for PN with balanced macronutrient supply according to current recommendations to protect the liver from steatosis.

Efficient achievement of enteral autonomy facilitates resolution of liver injury in necrotizing enterocolitis induced short bowel syndrome

Children with short bowel syndrome (SBS) are at high risk for intestinal failure associated liver disease (IFALD). The aim of this retrospective follow-up study was to compare weaning off parenteral nutrition (PN) and IFALD between necrotizing enterocolitis (NEC) and non-NEC induced SBS. Altogether, 77 patients with neonatal SBS treated by our multidisciplinary intestinal failure unit (NEC n = 38, non-NEC SBS n = 39) were included and followed-up at least for 2 years until median age of 10 years (interquartile range, 6.0-16). Occurrence and characteristics of IFALD was assessed with liver biopsies obtained at median age of 3.2 (1.0-6.7) years (n = 62) and serum liver biochemistry. Overall, NEC patients had less end-jejunostomies and autologous intestinal reconstruction surgeries performed compared to non-NEC patients (< 0.05), while remaining small bowel anatomy was comparable between groups. Cumulative weaning off PN was more frequent and duration of PN shorter among NEC patients (P < 0.05). Overall cumulative probability of histological IFALD was lower among NEC patients during whole follow-up period (P = 0.052) and at 10 years (P = 0.024). NEC patients had lower ALT and GGT levels at last follow-up (P < 0.05 for all). In univariate Cox regression analysis, absence of end-jejunostomy, NEC diagnosis, longer remaining small bowel length, multidisciplinary treatment and prematurity were predictive for weaning off PN, while NEC diagnosis and lower birth weight in addition to multidisciplinary care protected from histological IFALD. Neonates with NEC induced SBS reached enteral autonomy earlier than those with non-NEC SBS, which associated with more efficient resolution of histological IFALD among long-term survivors.

IFALD in children: What's new? A narrative review

Intestinal failure-associated liver disease (IFALD) is a progressive liver disease complicating intestinal failure (IF). It is a preventable and reversible condition, but at the same time, a potential cause of liver cirrhosis and an indication to combined or non-combined liver and small bowel transplantation. The diagnostic criteria are not yet standardized, so that its prevalence varies widely in the literature. Pathophysiology seems to be multifactorial, related to different aspects of intestinal failure and not only to the long-term parenteral nutrition treatment. The survival rates of children with IF have increased, so that the main problems today are preventing complications and ensuring a good quality of life. IFALD is one of the most important factors that limit long-term survival of patients with IF. For this reason, more and more interest is developing around it and the number of published articles is increasing rapidly. The purpose of this narrative review was to focus on the main aspects of the etiology, pathophysiology, management, prevention, and treatment of IFALD, based on what has been published mainly in the last 10 years. Controversies and current research gaps will be highlighted with the aim to pave the way for new project and high-quality clinical trials.

Liver PP2A-Cα Protects From Parenteral Nutrition-associated Hepatic Steatosis

BACKGROUND & AIMS

Parenteral nutrition (PN) is a lifesaving therapy for patients with intestinal failure. Hepatic steatosis is a potentially fatal complication of long-term PN, but the involved pathological mechanisms are incompletely unclarified. Herein, we identify the role of protein phosphatase 2A (PP2A) in the pathogenesis of parenteral nutrition-associated hepatic steatosis (PNAHS).

METHODS

Proteomic/phosphoproteomic analyses of liver samples from patients with PNAHS were applied to identify the mechanism of PNAHS. Total parenteral nutrition (TPN) mice model, in vivo, and in vitro experiments were used to assess the effect of PP2A-Cα on liver fatty acid metabolism.

RESULTS

Reduced expression of PP2A-Cα (catalytic subunit) enhanced activation of serine/threonine kinase Akt2 and decreased activation of adenosine monophosphate-activated protein kinase (AMPK) were associated with hepatic steatosis in patients with PNAHS. Mice given PN for 14 days developed hepatic steatosis, down-regulation of PP2A-Cα, activation of Akt2, and inhibition of AMPK. Hepatocyte-specific deletion of PP2A-Cα in mice given PN exacerbated Akt2 activation, AMPK inhibition, and hepatic steatosis through an effect on fatty acid degradation, whereas hepatocyte-specific PP2A-Cα overexpression significantly ameliorated hepatic steatosis accompanied with Akt2 suppression and AMPK activation. Additionally, pharmacological activation of Akt2 in mice overexpressing PP2A-Cα led to the aggravation of hepatic steatosis.

CONCLUSIONS

Our findings demonstrate that hepatic PP2A-Cα serves as a protective factor of PNAHS due to ameliorating hepatic steatosis and improving liver function. Our study provides a strong rationale that PP2A-Cα may be involved in the pathogenesis of PNAHS.

Intestinal failure-associated liver disease in the neonatal ICU: what we know and where we're going

PURPOSE OF REVIEW

Parenteral nutrition is an integral part of the care of infants in the neonatal ICU. However, prolonged use of parenteral nutrition can be associated with adverse outcomes, most notably parenteral nutrition-associated liver disease, now known as intestinal failure-associated liver disease (IFALD). This review highlights pertinent developments in the epidemiology of IFALD as it pertains to neonates and showcases recent advances in the pathophysiology, treatment, and outcomes of neonates with IFALD.

RECENT FINDINGS

The role of intravenous lipid emulsions in the pathogenesis, prevention, and treatment of IFALD remains a target for investigative studies. Recent data continues to support the use of fish-oil based intravenous lipids, but its use is limited due to concerns for essential fatty acid deficiency. Use of soy-based lipids and mixed lipids is not wrought with such concerns as these are often used at greater doses but their use is limited due to higher proinflammatory fatty acid content, increased phytosterols and decreased antioxidants, risk factors for the development of IFALD.

SUMMARY

Hepatic complications may limit the use of parenteral nutrition in the neonatal ICU. However, the pathophysiology of IFALD is continuing to be further elucidated and novel targets are being developed for the treatment of IFALD. As noninvasive disease monitoring strategies continue to be developed, early enteral nutrition ameliorates the risk of IFALD and should be considered when possible.

Infection Prevention and Management in Pediatric Short Bowel Syndrome

Short bowel syndrome (SBS) is a rare disease with potentially life-threatening consequences. In addition to intestinal failure-associated liver disease, infections and other complications related to central venous catheters (CVCs) cause a significant burden to patients with SBS and may even necessitate an intestinal transplant eventually. The need for long-term central venous access and the intestinal dysfunction associated with SBS drive the need for intestinal failure-specific approach to prevent and treat infections in patients with SBS. In bacterial infections, the line can often be salvaged with proficient antibiotic therapy. Repeated catheter replacements are predisposed to recurrent infections and thrombotic complications, which may limit the long-term survival of patients with SBS. Protocol-based CVC access procedures and daily care including taurolidine and ethanol catheter locks have been shown to reduce infection rates substantially. Compromised intestinal function in SBS predisposes to small bowel bacterial overgrowth, mucosal injury, and increased permeability. These pathophysiological changes are concentrated in a subset of patients with excessive bowel dilatation and frequent bowel-derived infections. In such patients, reconstructive intestinal surgery may be indicated. Probiotics have not been effective in infection prevention in SBS and carry a significant risk of complications. While more studies focusing on the prevention of infections and their complications are needed, protocol-based approach and multidisciplinary teams in the care of patients with SBS have been shown to reduce complications and improve outcomes.

Review article: insights into the bile acid-gut microbiota axis in intestinal failure-associated liver disease-redefining the treatment approach

BACKGROUND

Intestinal failure-associated liver disease (IFALD) increases mortality of patients with intestinal failure (IF), but lacks effective prevention or treatment approaches. Bile acids, gut microbiota and the host have close and complex interactions, which play a central role in modulating host immune and metabolic homeostasis. Increasing evidence suggests that derangement of the bile acid-gut microbiota (BA-GM) axis contributes to the development of IFALD.

AIMS

To review the BA-GM axis in the pathogenesis and clinical applications of IFALD, and to explore future directions for effective disease management.

METHODS

We conducted a literature search on bile acid and gut microbiota in IF and liver diseases.

RESULTS

The BA-GM axis demonstrates a unique IF signature manifesting as an increase in primary-to-secondary bile acids ratio, disturbed enterohepatic circulation, blunted bile acid signalling pathways, gut microbial dysbiosis, and altered microbial metabolic outputs. Bile acids and gut microbiota shape the compositional and functional alterations of each other in IF; collaboratively, they promote immune dysfunction and metabolic aberration in the liver. Diagnostic markers and treatments targeting the BA-GM axis showed promising potential in the management of IFALD.

CONCLUSIONS

Bile acids and gut microbiota play a central role in the development of IFALD and make attractive biomarkers as well as therapeutic targets. A multitarget, individualised therapy aiming at different parts of the BA-GM axis may provide optimal clinical benefits and requires future investigation.

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.

Long-term outcomes of various pediatric short bowel syndrome in China

PURPOSE

The goal of this study was to analyze long-term outcome of various pediatric short bowel syndrome (SBS) at an intestinal rehabilitation center in China.

METHODS

One hundred and fifty-seven children with SBS were enrolled in this study from October 1988 to July 2019. Their long-term follow-up outcome was analyzed according to the age of disease onset, parenteral nutrition (PN) duration, and anatomic types of short bowel, respectively. The clinical characteristics, which included demographics, the length of residual small bowel, PN duration, PN dependence, SBS-related complications such as IF-related liver disease (IFALD), catheter-related bloodstream infection (CRBI), and mortality were compared among the groups.

RESULTS

The main etiology for SBS were intestinal atresia, NEC, and volvulus. Five of 157 patients did not wean off PN. The incidence of IFALD and CRBI was 24.2 and 22.3%, respectively. Sixteen cases died because of infection and liver failure and eight patients lost to follow-up. The survival rate of the 157 patients was 84.7%. PN duration was longer in the infants and children group (284 ± 457 d vs. 110 ± 64 d, P = 0.021; R = 0.264, P = 0.001) and more patients did not wean off PN than in the neonates group (11.6% vs. 0, P = 0.001; R = 0.295, P < 0.001). Patients with PN with a duration of longer than 90 days had more CRBIs (30.6%, P = 0.025; R = 0.236, P = 0.003). Additionally, the rate of CRBI was higher in patients with stoma (30.0%, P = 0.032). There was no difference in mortality among the groups. In five PN dependence patients, none was SBS onset in neonates.

CONCLUSION

Pediatric patients with SBS could achieve favorable long-term survival and enteral autonomy. Different standards of SBS classification such as the age of disease onset, PN duration, and anatomic types of short bowel did not impact the overall mortality of pediatric SBS. Prolonged PN duration positively correlated with the age of disease onset and the incidence of CRBI. Patients with the complete continuity of intestinal tract suffered less from CRBI.

Increased Uric Acid, Gamma-Glutamyl Transpeptidase and Alkaline Phosphatase in Early-Pregnancy Associated With the Development of Gestational Hypertension and Preeclampsia

Background: Previous studies have reported that biomarkers of liver injury and renal dysfunction were associated with hypertensive disorders of pregnancy (HDP). However, the associations of these biomarkers in early pregnancy with the risk of HDP and longitudinal blood pressure pattern during pregnancy were rarely investigated in prospective cohort studies. Methods: A total of 1,041 pregnant women were enrolled in this prospective cohort study. BP was assessed in four stages throughout pregnancy. The following biomarkers were measured at early pregnancy before 18 weeks gestation: lactate dehydrogenase (LDH), aspartate aminotransferase to alanine aminotransferase ratio (AST/ALT), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP), uric acid (UA), and estimated glomerular filtration rate (eGFR). Linear mixed-effects and logistic regression models were used to examine the associations of these biomarkers with longitudinal BP pattern during pregnancy and HDP incidence, respectively. Results: In unadjusted models, higher serum UA, GGT, ALP, and LDH levels, as well as lower eGFR and AST/ALT, were associated with higher BP levels during pregnancy and an increased risk of HDP. After adjustment for maternal age, pre-pregnancy BMI and other potential confounders, UA, GGT, ALP, and LDH remained positively associated with both BP and HDP. However, eGFR and AST/ALT were not associated with HDP after adjusting for potential confounders. When including all 6 biomarkers simultaneously in multivariable analyses, increased UA, GGT, and ALP significantly associated with gestational hypertension and preeclampsia. Conclusion: This study suggests that increased UA, GGT, and ALP in early-pregnancy are independent risk factors of gestational hypertension and preeclampsia.