New approaches to understanding the etiology and treatment of total parenteral nutrition-associated cholestasis

Altered hepatic and intestinal homeostasis in a neonatal murine model of short-term total parenteral nutrition and antibiotics

Parenteral nutrition (PN) prevents starvation and supports metabolic requirements intravenously when patients are unable to be fed enterally. Clinically, infants are frequently provided PN in intensive care settings along with exposure to antibiotics (ABX) to minimize infection during care. Unfortunately, neonates experience extremely high rates of hepatic complications. Adult rodent and piglet models of PN are well-established but neonatal models capable of leveraging the considerable transgenic potential of the mouse remain underdeveloped. Utilizing our newly established neonatal murine PN mouse model, we administered ABX or controlled drinking water to timed pregnant dams to disrupt the maternal microbiome. We randomized mouse pups to PN or sham surgery controls +/- ABX exposure. ABX or short-term PN decreased liver and brain organ weights, intestinal length, and mucosal architecture (vs. controls). PN significantly elevated evidence of hepatic proinflammatory markers, neutrophils and macrophage counts, bacterial colony-forming units, and evidence of cholestasis risk, which was blocked by ABX. However, ABX uniquely elevated metabolic regulatory genes resulting in accumulation of hepatocyte lipids, triglycerides, and elevated tauro-chenoxycholic acid (TCDCA) in serum. Within the gut, PN elevated the relative abundance of Akkermansia, Enterococcus, and Suterella with decreased Anaerostipes and Lactobacillus compared with controls, whereas ABX enriched Proteobacteria. We conclude that short-term PN elevates hepatic inflammatory stress and risk of cholestasis in early life. Although concurrent ABX exposure protects against hepatic immune activation during PN, the dual exposure modulates metabolism and may contribute toward early steatosis phenotype, sometimes observed in infants unable to wean from PN.NEW & NOTEWORTHY This study successfully established a translationally relevant, murine neonatal parenteral nutrition (PN) model. Short-term PN is sufficient to induce hepatitis-associated cholestasis in a neonatal murine model that can be used to understand disease in early life. The administration of antibiotics during PN protects animals from bacterial translocation and proinflammatory responses but induces unique metabolic shifts that may predispose the liver toward early steatosis.

Bile acid-farnesoid X receptor-fibroblast growth factor 19 axis in patients with short bowel syndrome: The randomized, glepaglutide phase 2 trial

BACKGROUND

The gut-liver axis and enterohepatic circulation have gained increasing attention lately. Patients with short bowel syndrome (SBS) are, in fact, human knock-out models that may assist in the understanding of bile acid synthesis and regulation. We evaluated effect of glepaglutide (a long-acting glucagon-like peptide-2 analog) on bile acid synthesis (the enterohepatic circulation of bile acids and liver biochemistry in patients with SBS).

METHOD

In a single-center, double-blinded, dose-finding, crossover phase 2 trial, 18 patients with SBS were randomly assigned to 2 of 3 treatment arms (0.1, 1, and 10 mg) with daily subcutaneous injections of glepaglutide for 3 weeks. The washout period between the 2 treatment periods was 4-8 weeks. Measurements were performed at baseline and at the end of each treatment period and included postprandial plasma samples for fibroblast growth factor 19 (FGF19), 7α-hydroxy-4-cholesten-3-one (C4), total excretion of fecal bile acids, gene expression of farnesoid X receptor (FXR) in intestinal mucosal biopsies, total plasma bile acids, and liver biochemistry.

RESULTS

Compared with baseline, the median (interquartile range) postprandial response (area under the curve 0-2h) of FGF19 increased by 150 h × ng/L (41, 195; P = 0.001) and C4 decreased by 82 h × µg/L (-169, -28; p = 0.010) in the 10-mg dose. FXR gene expression did not change in any of the groups. Alkaline phosphatase significantly decreased.

CONCLUSION

Glepaglutide may stimulate the bile acid/FXR/FGF19 axis, leading to increased plasma concentrations of FGF19. Thereby, glepaglutide may ameliorate the accelerated de novo bile acid synthesis and play a role in the prevention and/or treatment of intestinal failure-associated liver disease.

Cholestatic liver injury induced by food additives, dietary supplements and parenteral nutrition

Cholestasis refers to the accumulation of toxic levels of bile acids in the liver due to defective bile secretion. This pathological situation can be triggered by drugs, but also by ingredients contained in food, food supplements and parenteral nutrition. This paper provides an overview of the current knowledge on cholestatic injury associated with such ingredients, with particular emphasis on the underlying mechanisms of toxicity.

Effect of bile acid supplementation on endogenous lipid synthesis in patients with short bowel syndrome: A pilot study

BACKGROUND & AIMS

Short bowel syndrome patients (SBS) receiving parenteral nutrition (PN) often have dyslipidaemia and can develop intestinal failure-associated liver disease (IFALD). These patients demonstrate increased cholesterol synthesis and hepatic lipogenesis. These lipid disturbances may be due to a decreased concentration of the bile acid pool or malabsorption. The aim of this pilot study was to evaluate the effect of bile acid administration on lipid synthesis in patients with SBS.

METHODS

The 24 h fractional synthesis rate (FSR) of cholesterol and triglycerides was measured by the isotopic method (deuterated water) before and after 4 months of ursodeoxycholic acid (UDCA) treatment (20 mg/kg/day). Five short bowel patients (age: 53.4 ± 19.2 years) who had normal liver function and lipid plasmatic profiles received 1920 ± 300 ml of PN for 151 ± 74 days (mean PN energy intake was 27.0 ± 6.0 kcal/kg body weight, composed with 3.87 ± 1.38 g/kg of carbohydrate, 0.72 ± 0.25 g/kg of fat and 1.10 ± 0.23 g/kg of amino acids). Plasma metabolites, liver enzymes, 7-α-OH-cholesterol and steatosis levels were also evaluated before and after treatment. Student's t-tests were performed, and the results were expressed in means (±SD).

RESULTS

After treatment, decreases in the absolute values of cholesterol synthesis (0.31 ± 0.12 mmol L^-1 to 0.24 ± 0.11 mmol L^-1; p < 0.05), FSR of cholesterol (31.6 ± 4.7% to 26.4 ± 4.7%; p = 0.06) and FSR of triglycerides (12.8 ± 5.8% to 9.2 ± 5.5%; p < 0.01) were observed. Cholesterol and alanine aminotransferase concentrations also decreased (ALT) (p < 0.05). The absolute values of triglyceride synthesis and triglyceride concentrations remained unchanged.

CONCLUSIONS

In SBS patients, UDCA decreases the hepatic synthesis of triglycerides and cholesterol. These results suggest that UDCA could prevent the onset of the IFALD.

Direct hyperbilirubinemia in newborns with gastroschisis

BACKGROUND

Patients with gastroschisis and prolonged total (or partial) parenteral nutrition (PN) commonly develop direct hyperbilirubinemia (DH).

OBJECTIVE

To quantify the prevalence and severity of DH in newborns with gastroschisis and characterize the diagnostic work-up for DH in this patient population.

DESIGN/METHODS

Retrospective chart review of patients born with gastroschisis between 2005 and 2015 for the first 6 months of life.

RESULTS

29 patients were identified with gastroschisis. Mean gestational age and birthweight were 36.4 (± 1.8) weeks and 2.5 (± 0.6) kg. 41% were treated with primary reduction versus staged closure. Peak total and direct bilirubin (DB) levels were 10.17 ± 6.21 mg/dL and 5.58 ± 3.94 mg/dL, respectively. 23 patients (79.3%) were diagnosed with DH and 78.2% underwent additional work-up for hyperbilirubinemia consisting of imaging and laboratory studies, none of which revealed a cause for DH other than the presumed PN-associated cholestasis. In all patients, DB began to decline within 1-10 days of initiation of enteral feeds.

CONCLUSION(S)

DH is common in patients with gastroschisis and is unlikely to be associated with pathology aside from PN. Additional work-up may lead to unnecessary resource utilization.

LEVELS OF EVIDENCE

Case series with no comparison group, Level IV.

Parenteral Nutrition-Associated Cholestasis Related to Parental Care

Parenteral nutrition-associated cholestasis (PNAC) is a complication not uncommon in the pediatric population. In severe cases, patients require a liver transplant. To our knowledge, we report the only case of PNAC with end-stage liver failure in a child with short bowel syndrome that resolved with a change in caretaker. Until his care was transferred from his abusive parents, he was frequently admitted for infection and sepsis. His liver function vastly improved from aspartate aminotransferase (AST) 3139 units/L, conjugated bilirubin 25.9 mg/dL to AST 47 units/L, direct bilirubin 0.3 mg/dL under the care of his attentive foster mother, and a liver transplant was no longer necessary. Bacterial infection and sepsis are risk factors correlated with patients with PNAC requiring liver transplant. Prevention of infection by a good caregiver may be a means to reduce the incidence of PNAC.

Diethylhexylphthalate Extracted by Typical Newborn Lipid Emulsions From Polyvinylchloride Infusion Systems Causes Significant Changes in Histology of Rabbit Liver

BACKGROUND

Looking for a candidate substance inducing hepatobiliary dysfunction under parenteral nutrition (PN) in newborns, we recently discovered that newborn infusions extract large amounts of the plasticizer diethylhexylphthalate (DEHP) from commonly used polyvinylchloride (PVC) infusion lines. This plasticizer is well known to be genotoxic and teratogenic in animals and to cause changes in various organs and enzyme systems even in humans. The aim of this study was to examine the effect of DEHP, extracted in the same way and in the same amount as in newborns, on livers of young rabbits.

METHODS

Prepubertal rabbits received lipid emulsion through central IV lines continuously for 3 weeks either via PVC or polyethylene (PE) infusion systems. Livers were examined after 1 and 3 weeks by light and electron microscopy.

RESULTS

By light microscopy, hydropic degeneration, single-cell necrosis, fibrosis, and bile duct proliferation were observed more in the PVC group. Electron microscopy revealed multiple nuclear changes, clusters and atypical forms of peroxisomes, proliferation of smooth endoplasmic reticulum, increased deposition of lipofuscin, and a mild perisinusoidal fibrosis only in the PVC group. These changes, which are generally regarded as reaction upon a toxic stimulus, could be exclusively attributed to DEHP.

CONCLUSIONS

This investigation proved that DEHP produces toxin-like changes in livers of young rabbits in the same dose, duration, and method of administration as in newborn infants. For this reason, it is likely that DEHP is the substance that causes hepatobiliary dysfunction in newborns under PN. Possible modes of action of DEHP are proposed.

Incidence and Risk Factors of Parenteral Nutrition-Associated Cholestasis in Omani Neonates: Single centre experience

OBJECTIVES

Parenteral nutrition-associated cholestasis (PNAC) is one of the most challenging complications of prolonged parenteral nutrition (PN) in neonates. There is a lack of research investigating its incidence in newborn infants in Oman and the Arab region. Therefore, this study aimed to assess the incidence of PNAC and its risk factors in Omani neonates.

METHODS

This retrospective study took place between January and April 2014. All neonates who received PN for ≥14 days during a four-year period (June 2009 to May 2013) at the neonatal intensive care unit (NICU) in Sultan Qaboos University Hospital, Muscat, Oman, were enrolled.

RESULTS

A total of 1,857 neonates were admitted to the NICU over the study period and 135 neonates (7.3%) received PN for ≥14 days. Determining the incidence of PNAC was only possible in 97 neonates; of these, 38 (39%) had PNAC. The main risk factors associated with PNAC were duration of PN, duration of enteral starvation, gastrointestinal surgeries, blood transfusions and sepsis. Neonates with PNAC had a slightly higher incidence of necrotising enterocolitis in comparison to those without PNAC.

CONCLUSION

This study found a PNAC incidence of 39% in Omani neonates. There were several significant risk factors for PNAC in Omani neonates; however, after logistic regression analysis, only total PN duration remained statistically significant. Preventive strategies should be implemented in NICUs so as to avoid future chronic liver disease in this population.

Preliminary findings of long-term neurodevelopmental outcomes of infants treated with intravenous fat emulsion reduction for the management of parenteral nutrition-associated cholestasis

INTRODUCTION

Parenteral nutrition-associated cholestasis (PNAC) is linked with the administration of soybean-based intravenous fat emulsion (IVFE). IVFE reduction (IFER) may be an effective management strategy for PNAC; however, long-term associated neurodevelopmental outcomes (NDOs) for infants undergoing IFER have not been measured previously. This single-institution, prospective study examined the risk for negative NDOs and key predictors of NDOs associated with IFER.

METHODS

Patients (2-5 years) treated with soybean-based IFER as neonates underwent NDO measurements, including Ages and Stages Questionnaires-3 (ASQ-3), Parents' Evaluations of Developmental Status (PEDS), and Behavior Assessment System for Children, Second Edition Preschool, Parent (BASC-2 PRS-P). The relationship between NDOs and predictive variables was evaluated.

RESULTS

A total of 25 children had a complete PEDS survey, and 17 were found to be "not at risk." The BASC-2 PRS-P evaluation (n = 18 patients) showed that all 4 composite domains fell within the normative developmental range, and 67%-89% of patients were observed to be "typically developing." For the primary outcome measure, ASQ-3, 82.4%-94.4% of patients were "not at risk." Logistical regression analyses were performed to examine risk factors contributing to negative NDOs. Of children completing all NDO studies, IFER-related variables (eg, development of essential fatty acid deficiency, duration of IFER, and mean IVFE dose) were not found to be predictors of adverse NDOs.

CONCLUSIONS

This study represents the first report of NDOs in pediatric patients treated with IFER. IFER-treated patients score within the normative range most of the time. IFER-related variables were not found to be associated with negative NDOs. The results set the stage for a larger, multicenter, prospective study.

Pathogenesis and treatment of parenteral nutrition-associated liver disease

BACKGROUND

Parenteral nutrition-associated liver disease (PNALD) has been common in patients who require long-term parenteral nutrition. PNALD develops in 40%-60% of infants on long-term parenteral nutrition compared with 15%-40% of adults on home parenteral nutrition for intestinal failure. The pathogenesis of PNALD is multifactorial and remains unclear. There is no specific treatment. Management strategies for its prevention and treatment depend on an understanding of many risk factors. This review aims to provide an update on the pathogenesis and treatment of this disease.

DATA SOURCES

A literature search was performed on the MEDLINE and Web of Science databases for articles published up to October 2011, using the keywords: parenteral nutrition associated liver disease, intestinal failure associated liver disease, lipid emulsions and fish oil. The available data reported in the relevant literatures were analyzed.

RESULTS

The literature search provided a huge amount of evidence about the pathogenesis and management strategies on PNALD. Currently, lack of enteral feeding, extended duration of parenteral nutrition, recurrent sepsis, and nutrient deficiency or excess may play important roles in the pathogenesis of PNALD. Recent studies found that phytosterols, present as contaminants in soy-based lipid emulsions, are also an important factor in the pathogenesis. Moreover, the treatment of PNALD is discussed.

CONCLUSIONS

The use of lipid emulsions, phytosterols in particular, is associated with PNALD. Management strategies for the prevention and treatment of PNALD include consideration of early enteral feeding, the use of specialized lipid emulsions such as fish oil emulsions, and isolated small bowel or combined liver and small bowel transplantation. A greater understanding of the pathogenesis of PNALD has led to promising interventions to prevent and treat this condition. Future work should aim to better understand the mechanisms of PNALD and the long-term outcomes of its treatment.

Parenteral nutrition-associated cholestasis: an American Pediatric Surgical Association Outcomes and Clinical Trials Committee systematic review

OBJECTIVE

The aim of this study was to review evidence-based data addressing key clinical questions regarding parenteral nutrition-associated cholestasis (PNAC) and parenteral nutrition-associated liver disease (PNALD) in children.

DATA SOURCE

Data were obtained from PubMed, Medicine databases of the English literature (up to October 2010), and the Cochrane Database of Systematic Reviews.

STUDY SELECTION

The review of PNAC/PNALD has been divided into 4 areas to simplify one's understanding of the current knowledge regarding the pathogenesis and treatment of this disease: (1) nonnutrient risk factors associated with PNAC, (2) PNAC and lipid emulsions, (3) nutritional (nonlipid) considerations in the prevention of PNAC, and (4) supplemental medications in the prevention and treatment of PNAC.

RESULTS

The data for each topic area relevant to the clinical practice of pediatric surgery were reviewed, evaluated, graded, and summarized.

CONCLUSIONS

Although the conditions of PNAC and PNALD have been well recognized for more than 30 years, only a few concrete associations and treatment protocols have been established.

Use of di(2-ethylhexyl)phthalate-containing infusion systems increases the risk for cholestasis

INTRODUCTION

Most polyvinylchloride infusion systems are plasticized with up to 60% of di(2-ethylhexyl)phthalate (DEHP). DEHP is easily extracted from the tubing by total parenteral nutrition (TPN) solutions and has been shown to have toxic effects on various organ systems including the liver in animals and humans. A role was postulated for DEHP in the development of hepatobiliary dysfunction in premature and newborn infants receiving parenteral nutrition, and the incidence of cholestasis was investigated after changing from polyvinylchloride infusion systems to polyvinylchloride-free infusion systems.

MATERIALS AND METHODS

Two 3-year periods from 1998 to 2004 were investigated retrospectively before and after changing from polyvinylchloride to polyvinylchloride-free infusion systems in our department. This resulted in 1 group of 30 patients treated with polyvinylchloride lines and a second group of 46 patients treated with polyvinylchloride-free lines. The 2 groups were examined for the incidence of cholestasis and other possible contributing factors. Statistics were performed by using SAS software (SAS Institute, Cary, NC).

RESULTS

After changing infusion systems, the incidence of cholestasis dropped from 50% to 13%. Using DEHP-plasticized polyvinylchloride infusion systems for TPN increased the risk for cholestasis by a factor of 5.6. The use of polyvinylchloride lines correlated strongly with the development of TPN-associated cholestasis (P = .0004).

CONCLUSIONS

Using DEHP-containing polyvinylchloride infusions systems contributes to the development of cholestasis. Therefore, the use of DEHP-free infusion systems for TPN is recommended, especially in premature and newborn infants.

Use of transanastomotic feeding tubes during esophageal atresia repair

PURPOSE

Esophageal atresia (EA) with tracheoesophageal fistula (TEF) type C accounts for 85% of all EA. In our center, patients were previously started on total parenteral nutrition (TPN) postoperatively and oral feedings initiated only after a contrast esophagogram. Our aim is to assess the benefit of intraoperatively placed transanastomotic feeding tubes (TAFTs).

METHODS

A 7-year retrospective review analyzed the outcomes of children with EATEF type C as they relate to the use of TAFT. Demographics, associated anomalies, operative findings, complications, duration of TPN, resumption of oral feeding, length of stay, and follow-up were examined.

RESULTS

Twenty-one patients had EATEF type C. Eleven (55%) and 9 (45%) patients were identified as nonfeeding tube (NFT) and TAFT groups, respectively. There were no differences in gestational age, birth weight, associated anomalies, and interval to operative intervention or operative time. Excluding one patient with a severe cardiac malformation in the NFT group, there were no significant differences in anastomotic leak (8% vs 22%), stenosis (36% vs 22%), TPN duration (20 days vs 12 days), and cholestasis (36% vs 11%).

CONCLUSION

Transanastomotic feeding tube may lead to shorter TPN duration and decreased cholestasis, but a larger prospective study would be required to prove these benefits and ensure that it does not increase anastomotic leaks. This could be done through an expanded Canadian Pediatric Surgery Network study.

Alteration of canalicular transporters in a mouse model of total parenteral nutrition

OBJECTIVES

Parenteral nutrition-associated liver disease (PNALD) is a major problem with prolonged total parenteral nutrition (TPN) administration. Our laboratory previously demonstrated significant changes in the expression of multidrug resistance genes (MDRs) 1 and 2, hepatocyte transporters, in a TPN mouse model. The present study hypothesized that these changes would lead to functional changes in the liver, and would contribute to the development of liver dysfunction.

MATERIALS AND METHODS

Mice received either intravenous saline and standard chow or TPN with or without intravenous lipids. Functional assays were performed after 7 days of infusion.

RESULTS

TPN with lipids led to a significant increase in serum bile acid levels, consistent with an early state of PNALD. Use of TPN without lipids prevented an elevation in bile acid levels. In both TPN groups, MDR2 expression was significantly (68%) lower than controls and bile phosphatidylcholine content, a functional measure of MDR2, was 40% less than controls. MDR1 expression in the TPN with lipid group was 31% higher than controls, whereas in the TPN without lipids mice there was no significant change. Hepatocyte extrusion of rhodamine dye, a measure of MDR1 function, declined only in the TPN with lipid group. Peroxisome proliferator-activated receptor-alpha expression decreased in both TPN groups. Fenofibrate given with TPN resulted in an increased expression of MDR1 and MDR2, and functionally increased hepatocyte rhodamine extrusion and presence of bile phosphatidylcholine in the TPN with lipid group.

CONCLUSIONS

The study shows that TPN led to alterations in the function of MDR1- and MDR2-expressed proteins. The changes help in the understanding of the mechanisms leading to PNALD, and suggest that fibrate administration may palliate these changes.

Cholestasis associated with small bowel atresia: do we always need to investigate?

BACKGROUND/PURPOSE

Cholestasis occurs frequently in patients with small bowel atresia (SBA) and is often attributed to prolonged parental nutrition. When severe or prolonged, patients may undergo unnecessary intensive or invasive investigation. We characterized cholestasis and analyzed the pertinence of investigating this patient population.

METHODS

With Research Ethics Board approval, patients with SBA between 1996 and 2005 were retrospectively reviewed. Demographics, location of atresia, operative findings, complications, investigations, resumption of feeding, duration of prolonged parental nutrition, and follow-up information were examined. Cholestasis was evaluated for incidence, severity, and evolution.

RESULTS

Fifty-five patients (29 male, 26 female), with a median gestational age and birth weight of 36 weeks and 2025 g, respectively, were reviewed. Care was withdrawn for 2 patients before repair. For the remaining 53 patients, SBA were duodenal atresia in 18, jejunoileal atresia in 32, and multiple atresia in 3. Of 53, 24 (45%) patients developed cholestasis postoperatively (direct/total bilirubin >20%). All patients with short bowel (4) and 60% (6/10) of patients with a delay of enteral feeding more than 14 days postoperatively had cholestasis. Ten patients (36%) proceeded with in-depth evaluations for cholestasis, with 8 (28%) undergoing liver biopsy. No patient had biliary atresia. No deaths were related to isolated cholestasis/cirrhosis. Cholestasis resolved spontaneously in all the survivors.

CONCLUSIONS

Small bowel atresia is frequently associated with postoperative cholestasis that will resolve with time. We recommend a more selective and expectant approach to SBA-associated cholestasis to minimize unnecessary investigations.

Hepatocanalicular transport defects: pathophysiologic mechanisms of rare diseases

The apical membrane of the hepatocyte fulfils a unique function in the formation of primary bile. For all important biliary constituents a primary active transporter is present that extrudes or translocates its substrate toward the canalicular lumen. Most of these transporters are ATP-binding cassette (ABC) transporters. Two types of transporters can be recognized: those having endogenous metabolites as substrates (which could be referred to as "physiologic" transporters) and those involved in the elimination of drugs, toxins, and waste products. It should be emphasized that this distinction cannot be strictly made as some endogenous metabolites can be regarded as toxins as well. The importance of the canalicular transporters has been recognized by the pathologic consequence of their genetic defects. For each of the physiologic transporter genes an inherited disease has now been identified and most of these diseases have a quite serious clinical phenotype. Strikingly, complete defects in drug transporter function have not been recognized (yet) or only cause a mild phenotype. In this review we only briefly discuss the inherited defects in transporter function, and we focus on the pathophysiologic concepts that these diseases have generated.

Parenteral nutrition-associated liver disease and the role for isolated intestine and intestine/liver transplantation

Parenteral nutrition-associated liver disease (PNALD) is the most devastating complication of long-term parenteral nutrition therapy. Because its progression is typically insidious and its long-term consequences are generally underappreciated, PNALD is often recognized too late, when liver injury is irreversible. When end-stage liver disease (ESLD) develops in these patients, most potential interventions are futile and transplantation of both an intestine and a liver becomes the only viable option, despite the relatively poor outcomes associated with this combined procedure. Although likely multifactorial in origin, the etiology of PNALD is poorly understood. Early clinical intervention with a combination of nutritional, medical, hormonal, and surgical therapies can be effective in preventing liver disease progression. If these interventions fail, intestinal transplantation should be performed expeditiously before development of ESLD mandates simultaneous inclusion of a liver graft as well.

Taurine and cholestasis associated to TPN. Experimental study in rabbit model

Taurine seems to be essential in the newborn for bile acid (BA) tauroconjugation, and its deficiency has been implicated in total parenteral nutrition-associated cholestasis (TPN-AC). Our purpose was to study the relationship between taurine (Ta) and TPN-AC in rabbits, which have a similar biliary metabolism to that of humans. We used 40 young rabbits, fed for 10 days according to the following four groups: GA [10] given TPN, with amino acid solution (AA) but without taurine (Ta) or its AA-precursors (methionine, cysteine, and serine); GB [10] the same but only without taurine; GC [10] the same but with taurine and its precursors; and GD [10] the control group with oral nutrition and saline infusion. Complete blood and bile analytical data were obtained and analyzed, including plasma AA and BA. Liver samples were studied under optical and electron microscopy. Serum: In GC there was a 20% increase in the AA-precursors, but paradoxically it was greater in GA. Bile: In GC there was 30% more excretion of total and free BA compared with less than 20% in GA and GB. Regarding toxic BA, there was a 15% decline in GLC3S excretion, but more than 20% in LCA excretion, than in GA and GB. Moreover, in GC the glyco-/tauro-conjugate ratio was worse than in the other groups. Histomorphology: While in GA and GB liver steatosis was diffuse (microsteatohepatitis type), in GC there was macrosteatosis with mitochondria-surrounded lipid droplets. In GA and GB, the canaliculi appeared dilated, with abundant bile plugs and loss of microvilli. There are signs that taurine may protect against TPN-AC. The mechanism does not seem to be BA tauroconjugation, but probably taurine's antioxidant, membrane stabilization (with Ca2+ and HCO3-), and/or osmotic effects.

High serum phytosterol levels in short bowel patients on parenteral nutrition support

BACKGROUND & AIMS

Patients with short bowel syndrome (SBS) are often depending on parenteral nutrition support (PNS), sometimes complicated by liver dysfunction. Phytosterols in parenteral lipid emulsions have been suspected to be responsible for cholestasis in paediatric nutrition support. The aim of the present study was to evaluate phytosterol intake and serum phytosterol levels in adult SBS patients.

METHODS

We quantified serum levels of phytosterols, cholesterol, and markers for bile acid and cholesterol synthesis, by gas or liquid chromatography in 21 healthy controls, and in 24 adult SBS-patients, 8 with and 16 without PNS. Phytosterols and cholesterol in parenteral lipid emulsions were also quantified.

RESULTS

Serum levels in SBS-patients without PNS; with PNS; and in controls, were on average for phytosterols 11; 63; and 23 micromol/l (P<0.05 for differences), cholesterol 4,2; 3,8; and 5,1 mmol/l, lathosterol 808; 824; and 228 micromol/100 mmol cholesterol, and 7alpha-hydroxy-4-cholesten-3-one 207;191; and 18 nmol/l, respectively (P<0.05 between controls and SBS). Phytosterols in lipid emulsions ranged from 591 to 958 micromol/l.

CONCLUSIONS

SBS-patients on PNS have higher serum levels of phytosterols than other SBS-patients and controls, possibly because of phytosterols in lipid emulsions. Patients with SBS, regardless of nutrition support, have lower serum levels of cholesterol but higher cholesterol and bile acid synthesis compared to controls.

The role of enteral nutrition in the reversal of parenteral nutrition-associated liver dysfunction in infants

BACKGROUND

Liver dysfunction in children dependent on parenteral nutrition (PN) is well established, and the extent of hyperbilirubinemia has been shown to correlate with morbidity and mortality. The aim of this study was to assess whether increasing provisions of enteral nutrition can improve PN-associated hyperbilirubinemia over time.

METHODS

A retrospective review was conducted on infants in our institution's Short Bowel Syndrome Clinic from 1999 to 2004. Inclusion criteria included PN duration more than 1 month, serum direct bilirubin more than 3 mg/dL while on PN, and tolerance of full enteral nutrition with eventual discontinuation of PN. Paired t tests were used for statistical analyses.

RESULTS

Twelve infants were identified with a PN duration of 5 +/- 1 months. Five patients underwent liver biopsy while on PN, and histological evidence of cholestasis was found on all specimens. Peak total and direct bilirubin levels were 10.5 +/- 1.9 and 7.0 +/- 1.6 mg/dL, respectively, and occurred at time of PN discontinuation. Only 2 patients had improvement in serum bilirubin levels before initiation of full enteral nutrition. After initiation of full enteral nutrition and discontinuation of PN, all patients achieved permanent normalization of bilirubin levels by 4 months (P < .05) after a 1-month plateau phase. Alkaline phosphatase levels approached reference range within this time but were not significant.

CONCLUSION

These data demonstrate for the first time that although PN-dependent infants can achieve normalization of marked hyperbilirubinemia with enteral nutrition, the improvement in liver function usually begins only after full enteral nutrition is tolerated and PN is withdrawn. These findings support the aggressive weaning of PN to enteral nutrition in infants with short bowel syndrome.

Use of cholecystokinin-octapeptide for the prevention of parenteral nutrition-associated cholestasis

OBJECTIVE

To determine whether cholecystokinin-octapeptide (CCK-OP) would prevent or ameliorate parenteral nutrition-associated cholestasis (PNAC) among high-risk neonates treated with total parenteral nutrition.

STUDY DESIGN

This was a multicenter, double-blind, randomized, controlled trial conducted between 1996 and 2001.

PATIENTS

Neonates at risk for the development of PNAC included very low birth weight neonates and those with major surgical conditions involving the gastrointestinal tract.

SETTING

Tertiary care hospitals.

INTERVENTION

Patients were randomized to receive CCK-OP (0.04 mug/kg per dose, twice daily) or placebo. Eligible infants were all <30 days of age. Patients were enrolled within 2 weeks after birth or within 7 days after surgery.

OUTCOME MEASURES

The primary outcome measure was conjugated bilirubin (CB) levels, which were measured weekly. Secondary outcome measures included incidence of sepsis, times to achieve 50% and 100% of energy intake through the enteral route, number of ICU and hospital days, mortality rate, and incidences of biliary sludge and cholelithiasis.

RESULTS

A total of 243 neonates were enrolled in the study. CCK-OP administration did not significantly affect CB levels (1.76 +/- 3.14 and 1.93 +/- 3.31 mg/dL for CCK-OP and placebo groups, respectively; mean +/- SD). Secondary outcome measures also were not significantly affected by the study drug.

CONCLUSIONS

Use of CCK-OP failed to reduce significantly the incidence of PNAC or levels of CB. CCK-OP had no effect on other secondary measures and should not be recommended for the prevention of PNAC.

Hepatic copper in patients receiving long-term total parenteral nutrition

GOALS

To assess the possibility of iatrogenic hepatic copper overload in adult patients on long-term total parenteral nutrition (TPN).

BACKGROUND

TPN predisposes to hepatic copper accumulation through disturbances of the enterohepatic bile acid pool, but iatrogenic copper overload through TPN solutions may occur as well.

STUDY

Quantitative hepatic copper and multiple clinical, biochemical, and histopathologic parameters were compared between patients with long-term TPN associated liver disease (n = 28) and patients with drug-induced cholestatic liver disease (n = 10).

RESULTS

Eighty-nine percent of TPN patients and all controls had mildly elevated hepatic tissue copper, but 29% of TPN patients had levels above the diagnostic threshold for Wilson's disease. Quantitative hepatic copper correlated positively with serum aspartate aminotransferase (P = 0.001, r = 0.59), total bilirubin (P < 0.001, r = 0.65), and direct bilirubin (P < 0.001, r = 0.63) in TPN patients, but not in controls. The amount of hepatic copper did not correlate with the duration of TPN (median, 1.9 years; range, 0.3-18.0 years) or serum copper levels. TPN patients with significant cholestasis accumulated more copper than patients with no or only minimal cholestasis (P = 0.002).

CONCLUSIONS

Significant hepatic copper overload in TPN patients occurs through chronic cholestasis in TPN-associated liver disease and is independent from the total duration of TPN. Iatrogenic copper overload through trace elements in TPN solutions does not seem to be a significant factor.

Study of the clinical effects of postoperative parenteral nutrition in 15 horses

Several clinical variables were compared in two groups of 15 horses recovering from resection and anastomosis of a strangulated small intestine; 15 were treated with parenteral nutrition and 15 were starved routinely. There was some evidence that parenteral nutrition had a short-lived adverse effect on both the catheter sites and gastric emptying, but there were no marked adverse clinical effects and no evidence of any improvement in the horses' condition.

Parenteral nutrition-associated liver complications in children

Parenteral nutrition is a life-saving therapy for patients with intestinal failure. It may be associated with transient elevations of liver enzyme concentrations, which return to normal after parenteral nutrition is discontinued. Prolonged parenteral nutrition is associated with complications affecting the hepatobiliary system, such as cholelithiasis, cholestasis, and steatosis. The most common of these is parenteral nutrition-associated cholestasis (PNAC), which may occur in children and may progress to liver failure. The pathophysiology of PNAC is poorly understood, and the etiology is multifactorial. Risk factors include prematurity, long duration of parenteral nutrition, sepsis, lack of bowel motility, and short bowel syndrome. Possible etiologies include excessive caloric administration, parenteral nutrition components, and nutritional deficiencies. Several measures can be undertaken to prevent PNAC, such as avoiding overfeeding, providing a balanced source of energy, weaning parenteral nutrition, starting enteral feeding, and avoiding sepsis.

The influence of L-glutamine on the depression of hepatic cytochrome P450 activity in male rats caused by total parenteral nutrition

Total parenteral nutrition (TPN) bypasses the gut leading to intestinal and hepatic dysfunction, including decreased hepatic cytochrome P450 (P450) activity. Glutamine prevents the TPN-associated changes in gut function and morphology. This study examined the effect of glutamine supplementation on hepatic P450 activities in male Sprague-Dawley rats receiving continuous TPN. Animals received continuous lipid-free TPN for 7 days with 0, 0.1, or 4.5% glutamine. Surgical controls were allowed free access to rat chow. The V(max)/K(m) ratios (intrinsic clearance) for the formation of 4-hydroxymidazolam (CYP3A) were 12.8, 14.6, and 27.7 microl/min/mg for TPN treatment with 0, 0.1%, or 4.5% glutamine, respectively, compared with a chow-fed control (37.1 microl/min/mg). The corresponding values for 1'-hydroxymidazolam formation (CYP3A) were 3.7, 6.1, 11.7, and 15.2 microl/min/mg, respectively. The addition of glutamine to TPN similarly affected the formation rates for 2beta- and 6beta-hydroxytestosterone (CYP3A), and these metabolite formation rates were highly correlated (r = 0.865; p < 0.001). The formation rates for 2alpha- and 16alpha-hydroxytestosterone (CYP2C) were also highly correlated (r = 0.892; p < 0.001). Parenteral glutamine modified the TPN-associated suppression of CYP3A and CYP2C activities in adult male rats receiving TPN.

Changing profile of parenteral nutrition in pediatric surgery: a 30-year experience at one institute

BACKGROUND

Due to technical refinements and steady advances in the development of highly sophisticated nutrient solutions consisting of optimal combinations of macronutrients and micronutrients, parenteral nutrition (PN) is now playing an important role in patient management. However, some PN-associated complications, such as catheter-related sepsis (CRS) and cholestasis, continue at high incidence, particularly in neonates. The objective of this study was to investigate the changing profiles of PN over the past 30 years in our department.

METHODS

The medical records of 893 children (225 neonates, 245 infants, 261 preschool-age children, and 162 school-age children) who were placed on PN for >7 days in our department were reviewed, and the following data were extracted: birth weight, underlying disease, indications for PN, PN delivery route, type of catheter used, duration of PN, substrate and energy intake, type of amino acid solution used, and incidence of complications including CRS and liver dysfunction. The results were analyzed by dividing the patients into 3 groups according to their basic stages in management of PN and consisted of group 1 (1970 to 1979), group 2 (1980 to 1989), and group 3 (1990 to 1999). The parameters were compared in each group.

RESULTS

The total number of patients in each group showed no significant difference; however, the percentage of low birth-weight neonates increased in group 3. In group 1, 85% of PN was administered through the peripheral vein; in group 2, 51.2%; and in group 3, 9.7%. The total calorie and nutrient intake decreased in groups 2 and 3 compared with group 1, particularly regarding fat intake. In groups 1 and 2, commercially available amino acid solution based on the Food and Agriculture Organization/World Health Organization formula was usually used as the nitrogen source, but in group 3, it was changed to an amino acid solution for children. CRS decreased significantly, particularly in neonates, and occurred at a rate of 45.4% in group 1, 10.7% in group 2, and 1.5% in group 3. The incidence of liver dysfunction also showed a decrease: 35.7% in group 1, 22.3% in group 2, and 18.0% in group 3. A multivariate analysis showed a strong relationship between PN-related liver dysfunction and the duration of PN, the presence of infection, and the type of amino acid solution used.

CONCLUSIONS

PN via central venous catheters has been regarded as safe and effective treatment in pediatric surgical patients. Over the past 30 years, the incidence of CRS has decreased. However, PN-related liver dysfunction remains a problem, particularly in patients receiving long-term PN.