Parenteral nutrition-associated liver complications in children

Overview of pediatric short bowel syndrome

Short bowel syndrome (SBS) is a malabsorptive state occuring as a result of surgical resection or congenital disease of a significant portion of the small intestine . The amount of resection or remaining bowel generally dictates the degree of malabsorption and consequentely the need for specialized enteral nutrition or parenteral nutrition (PN). Intestinal failure in the context of SBS is defined as a dependence on PN to maintain minimal energy and fluid requirement for growth in children. Common causes of SBS in infants and children include necrotizing enterocolitis, midgut volvulus, intestinal atresia, and gastroschisis. Early identification of patients at risk for long-term PN dependency is the first step toward avoiding severe complications. Close monitoring of nutritional status, steady and early introduction of enteral nutrition, and aggressive prevention, diagnosis, and treatment of infections such as central venous catheter sepsis and bacterial overgrowth can significantly improve the prognosis. Intestinal transplantation is an emerging treatment that may be considered when intestinal failure is irreversible and children are experiencing serious complications related to TPN administration.

Could lipid infusion be a risk for parenteral nutrition-associated cholestasis in low birth weight neonates?

To assess whether lipid infusion could be a risk factor for parenteral nutrition-associated cholestasis (PNAC) in low birth weight neonates, 22 newborns with cholestasis (29.8 +/- 1.6 weeks, 1298 +/- 217 g) were compared with 22 without cholestasis (29.5 +/- 1.7 weeks, 1286 +/- 363 g). The mean level of peak direct bilirubin for the cholestasis group was 4.6 mg/dl compared to 1.2 mg/dl for the noncholestasis group. A univariate analysis revealed that PNAC was significantly related to duration of fasting (p = 0.008) and parenteral nutrition (p < 0.0001), days of antibiotics use (p = 0.025), positive C-reactive protein (p = 0.018) or gastric culture (p = 0.018), and feeding intolerance (p < 0.0001). Total amino acid amount (p < 0.0001), total lipid amount (p < 0.0001), and average daily lipid amount (p = 0.002) were significantly higher in the cholestasis group than in the noncholestasis group. Conversely, prenatal administration of dexamethasone was a significant protective factor of PNAC (p = 0.008). Logistic regression analysis revealed that the cumulative amount of lipid infusion was an independent risk factor for PNAC (p = 0.041; OR 1.174; CI 1.007-1.369). We suggest that decreasing the cumulative load of amino acids and intralipids with early trophic feeding, control of infection, and prenatal administration of dexamethasone could possibly attenuate the severity of PNAC.

Percutaneous cholangiography for the treatment of parenteral nutrition-associated cholestasis in surgical neonates: preliminary experience

OBJECTIVE

Parenteral nutrition-associated cholestasis (PNAC) occurs in up to 60% of surgical neonates with intestinal failure, and 10% will develop end-stage liver failure. Our aim was to evaluate the effectiveness of percutaneous transhepatic transcholecystic cholangiography (PTTC) in the treatment of PNAC in surgical neonates.

METHODS

A retrospective double cohort study of surgical neonates with PNAC was conducted. Patients with PNAC who received PTTC were compared to controls matched by gestational age, birth weight, sex, and parenteral nutrition duration. Percutaneous transhepatic transcholecystic cholangiography was performed under general anesthesia with ultrasound guidance. Analysis was performed using paired Student's t test and McNemar chi2 test.

RESULTS

Nine PTTC patients and 9 controls were similar in mean age (35.5 +/- 3.1 vs 35.6 +/- 4.2 weeks, P = .85), birth weight (2531 +/- 879 vs 2692 +/- 1052 g, P = .28), sex (all males), and parenteral nutrition duration (51.2 +/- 29.8 vs 53.3 +/- 33.3 days, P = .74). Percutaneous transhepatic transcholecystic cholangiography was performed in 9 patients at mean corrected age of 5.5 +/- 3.4 weeks and weight of 3621 +/- 546 g. All control patients and 8 (88.9%) of 9 PTTC patients had eventual resolution of hyperbilirubinemia. Percutaneous transhepatic transcholecystic cholangiography patients experienced a more rapid rate of resolution of their cholestasis, and the mean time to resolution of conjugated bilirubin was less in the PTTC group (8.5 +/- 3.2 vs 18.5 +/- 7.6 weeks, P = .02).

CONCLUSION

Therapeutic PTTC results in a 50% reduction in the time to PNAC resolution. Percutaneous transhepatic transcholecystic cholangiography may have a role as active therapy to slow progression of PNAC in surgical neonates with intestinal failure.

Stigmasterol, a soy lipid-derived phytosterol, is an antagonist of the bile acid nuclear receptor FXR

Phytosterols, components of soy-derived lipids, are among the proposed exacerbants of parenteral nutrition-associated cholestasis (PNAC). We investigated whether phytosterols contribute to bile acid (BA)-induced hepatocyte damage by antagonizing a nuclear receptor (NR) critically involved in hepatoprotection from cholestasis, FXR (farnesoid X receptor, NR1H4). In HepG2 cells, stigmasterol acetate (StigAc), a water-soluble Stig derivative, suppressed ligand-activated expression of FXR target genes involved in adaptation to cholestasis (i.e. BSEP, FGF-19, OSTalpha/beta). Furthermore, StigAc antagonized BA-activated, FXR target genes SHP and BSEP in FXR+/+, but not in FXR-/- mouse hepatocytes. Both Stig and StigAc inhibited BA-activated, FXR-dependent reporter gene expression in transfected HepG2 cells, whereas the most prevalent phytosterol in lipids, beta-sitosterol, had no inhibitory effect. Finally, among six ligand-activated NR-ligand binding domains (LBDs) tested, antagonism by StigAc was specific to only two (FXR and PXR, pregnane X receptor, NR1I2). We demonstrate that Stig, a phytosterol prevalent in soy-derived PN lipid solutions, is a potent in vitro antagonist of the NR for bile acids FXR.

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

Since its introduction into clinical practice, parenteral nutrition has revolutionized the care of premature neonates. Serum transaminase and bilirubin levels are commonly elevated in infants on parenteral nutrition, but their normalization is typical in the setting of short-term administration of parenteral nutrition uncomplicated by sepsis. Premature infants who require long-term parenteral nutrition are, however, at severe risk for developing life-threatening hepatic complications. These complications include cirrhosis, liver failure, and the concomitant risks of sepsis, coagulopathy and death. Premature infants and those with short-bowel syndrome are most susceptible to these morbid outcomes. Although it has been more than a quarter of a century since parenteral nutrition was first introduced and its association with hepatic complications described, the precise etiology of parenteral nutrition associated cholestasis (PNAC) remains a mystery; however, our understanding of the molecular components that contribute to PNAC has improved substantially. In this Review, we summarize the fundamentals of PNAC, describe animal models of the disease, review the hepatic bile acid transporters that are crucial for bile acid homeostasis, and define the roles that endotoxin, genetics, and the components of parenteral nutrition are likely to have in the molecular pathogenesis of this life-threatening condition.

Total parenteral nutrition leads to alteration of hepatocyte cell cycle gene expression and proliferation in the mouse

Total parenteral nutrition (TPN) is correlated with progressive liver injury. Such injury may be associated with either an increase or decrease in hepatocyte growth. The goal of these experiments was to determine TPN-related alterations in intrahepatic genes, as they relate with the cell cycle, using microarray techniques. After 7 days of infusion of saline or TPN-solution, hepatocyte gene expression was examined with a 5000-cDNA microarray chip. TPN was associated with an up-regulation of the cyclin kinase Cdc25B mRNA, which controls the cell cycle at the G2/M phase. Based on this, our studies were directed at alterations in genes related to mitosis in this phase of the cell cycle. mRNA expression of mitotic phase inducers and inhibitors were examined. Cdc25B1 mRNA expression increased with TPN. TPN also led to additional significant alterations in the expression of other factors which mediate proliferation in this phase of mitosis. Histologically, TPN resulted in a significant decline in hepatocyte proliferation. Coincident with the alteration in cyclin expression was a significant decrease in hepatocytes in the G2/M phase with TPN administration. This study demonstrates significant alterations in cell cycle gene expression with TPN. The findings correlate with a loss of hepatocyte proliferation and may give insight into the potential mechanism of TPN-induced hepatocyte injury.

Complications of parenteral nutrition

Parenteral nutrition plays a vital role for patients with intestinal failure and those who are unable to maintain oral or enteral nutrition alone. Parenteral nutrition has been shown to improve clinical outcome in patients with malnutrition and intestinal tract dysfunction. The use of parenteral nutrition is not without risk of serious complications. Parenteral nutrition complications can be divided into mechanical related to vascular access, septic, and metabolic. This article provides a review on the short- and long-term complications of parenteral nutrition and their management.

Parenteral nutrition-associated liver disease in adult and pediatric patients

There are essentially 3 types of hepatobiliary disorders associated with parenteral nutrition (PN) therapy: steatosis, cholestasis, and gallbladder sludge/stones. Reported prevalence rates of PN-associated liver disease (PNALD) vary greatly, and there are distinct differences between adult and pediatric patients. Various etiologic factors have been evaluated for significance in contributing to PNALD, including enteral feeding history, septic events, bacterial overgrowth, length of intestinal resection, and prematurity/low birth weight. Etiologic factors specifically related to the PN formulation or nutrient intake have also been evaluated, including excessive calorie intake, dextrose-to-lipid ratio, amino acid dose, taurine deficiency, IV fat emulsion (IVFE) dose, carnitine deficiency, choline deficiency, and continuous vs cyclic infusion. Minor increases in serum aminotransferase concentrations are relatively common in patients receiving PN therapy and generally require no intervention. The primary indicator of cholestasis is a serum conjugated bilirubin >2 mg/dL. When a patient receiving PN develops liver complications, it is necessary to rule out all treatable causes and minimize other risk factors. All potential hepatotoxic medications and herbal supplements should be eliminated. Modifications to the PN regimen that may be helpful include reduction of calories, reduction of IVFE dose to <1 g/kg/d, supplementation of taurine in the infant, and use of cyclic infusion. Initiation of even small amounts of enteral nutrition and use of ursodiol may be beneficial in stimulating bile flow. In the long-term PN patient with severe and progressive liver disease, intestinal or liver transplantation may be the only remaining treatment option.

Isolated Liver Transplantation in an Infant With Ultrashort Gut

Intestinal function in children with very short bowel syndrome and related intestinal failure may improve after isolated liver transplantation. An infant with an ultrashort gut, ileo-cecal valve, and whole colon received total parenteral nutrition from the first days of life. Enteral feeding failed because of the progressive dilatation of the jejunal portion and motility disorders. He developed early severe cholestatic liver disease (aspartate transferase 186, alanine transferase 103 U/L, serum bilirubin 8.4 mg/dL) and subsequent liver failure. At 8 months of age, he benefited from isolated liver transplantation (left segment graft from living donor). His early posttransplant evolution was characterized by recovery of oral alimentation, improvement of digestive and absorption functions, but he did not achieve TPN-independence. At 20 months, 50% to 60% of his energy needs were covered by parenteral nutrition and he has satisfactory growth indices (3rd percentile for weight and height), reduced stool volume, and frequency. Isolated liver transplantation allowed, in this particular case, time for further intestinal adaptation thereby avoiding the need for intestinal transplantation early in life.

Ursodeoxycholic Acid for the Treatment of Parenteral Nutrition–Associated Cholestasis in Pediatric Patients

Objective:

To determine the relative safety and efficacy of ursodeoxycholic acid (UDCA) in children and neonates with parenteral nutrition–associated cholestasis (PNAC).

Data Sources:

A comprehensive search (up to May 29, 2006) of the following databases was conducted to identify relevant prospective, randomized, double-blind clinical trials and systematic reviews: Ovid–MEDLINE, PubMed, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Abstracts of Reviews of Effects, and the Centre for Reviews and Dissemination. In addition, reference lists from retrieved articles were searched to identify trials or systematic reviews not identified in the search of electronic databases. Also, the manufacturer of UDCA was contacted regarding access to any other unpublished trials that could be included in this review.

Study Selection and Data Extraction:

Prospective, double-blind, randomized, controlled trials of neonates (<36 wk gestational age) and/or children (0–18 y) who developed PNAC while receiving parenteral nutrition were included in the analysis. Articles were evaluated with specific focus placed on the following hierarchy of outcomes: mortality, nonfatal serious adverse events, liver failure, infection, sepsis, return of liver function test results to within normal ranges, and relief of pruritus.

Data Synthesis:

No prospective, double-blind, randomized, controlled trials assessing the efficacy and safety of UDCA for the treatment of PNAC in children and/or neonates were identified. Five retrospective chart reviews and/or case series were identified; however, the results of these studies were conflicting and do not provide sufficient evidence of the safety and efficacy of UDCA for the treatment of PNAC.

Conclusions:

There is no evidence from prospective, double-blind, randomized, controlled trials in neonates and/or children with PNAC regarding the relative safety and efficacy of UDCA therapy.

Intestinal failure-associated liver disease: what do we know today?

Intestinal failure-associated liver disease develops in 40% to 60% of infants who require long-term total parenteral nutrition (TPN) for intestinal failure and 15% to 40% of adults on home parenteral nutrition. The clinical spectrum includes hepatic steatosis, cholestasis, cholelithiasis, and hepatic fibrosis. Progression to biliary cirrhosis and the development of portal hypertension and liver failure occurs in a minority but is more common in infants and neonates than in adults. The pathogenesis is multifactorial. In infants it is related to prematurity, low birth weight, duration of PN, short bowel syndrome requiring multiple laparotomies, and recurrent sepsis. Other important mechanisms include lack of enteral feeding, which leads to reduced gut hormone secretion; reduction of bile flow and biliary stasis, which leads to the development of cholestasis; and biliary sludge and gallstones, which exacerbate hepatic dysfunction. In adults, IFALD is less common and related to age, length of time on PN, total caloric intake, and lipid or glucose overload. In preterm infants, a deficiency of taurine or cysteine may play a role, whereas in both adults and children, choline deficiency may exacerbate IFALD. Lipid emulsions, choline deficiency, and manganese toxicity are associated with both hepatic steatosis and cholestasis in adults and children. Management strategies for the prevention of intestinal failure-induced liver disease include early enteral feeding, a multidisciplinary approach to the management of parenteral nutrition, and aseptic catheter techniques to reduce sepsis. The addition of choline, taurine, and cysteine to PN solutions may also play a role. Oral administration of ursodeoxycholic acid may improve bile flow and reduce gallbladder stasis. Survival after either isolated small bowel or combined liver and small bowel transplantation is approximately 50% at 5 years, making this an acceptable therapeutic option in adults and children with irreversible liver and intestinal failure.

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.

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.

Sincalide in Patients with Parenteral Nutrition—Associated Gallbladder Disease

OBJECTIVE

To review the role of sincalide in treating and preventing parenteral nutrition (PN)–associated gallbladder disease.

DATA SOURCES

A MEDLINE (1996–March 2004) search was performed using the key terms cholecystokinin, sincalide, parenteral nutrition, cholelithiasis, cholestasis, and sludge.

DATA SYNTHESIS

Five human studies investigated the safety and efficacy of sincalide in patients with PN-associated gallbladder disease. Sincalide at intravenous doses of 0.04 μg/kg 3 times daily increased bile flow and improved serum bilirubin levels. However, patients with advanced liver disease did not respond to sincalide therapy. Long-term follow-up data on sincalide effects on liver disease progression are not yet available.

CONCLUSIONS

Sincalide improved the signs of cholestasis. However, its long-term effects in preventing and treating PN-associated gallbladder disease remain unknown and its routine use for this indication cannot be recommended at this time.

Liver disease due to parenteral and enteral nutrition

Liver disease due to parenteral and enteral nutrition is a well-recognized iatrogenic phenomenon, but its cause and pathogenesis have not been clearly elucidated. Various mechanisms have been postulated, but it is likely that the cause is multifactorial with significant interplay among several factors. A preventive approach to management is ideal but awaits a more complete understanding of the pathophysiology. A variety of management strategies has been proposed in small case series, but level 1 evidence-based guidelines have yet to be established. Although an abundance of both clinical and animal studies exist regarding liver disease associated with parenteral nutrition (PN), there is a paucity of data regarding enteral nutrition (EN)-associated hepatic disease. The latter probably reflects differences in the frequency and severity of PN- versus EN-associated liver disease. This article addresses the two routes of nutritional support individually, with the major focus on PN-associated liver disease.

Ursodeoxycholic acid (UDCA) therapy in very-low-birth-weight infants with parenteral nutrition-associated cholestasis

OBJECTIVE

To determine the effect of ursodeoxycholic acid (UDCA) in very-low-birth-weight (VLBW) infants with parenteral nutrition-associated cholestasis (PNAC).

STUDY DESIGN

A retrospective study of all VLBW infants with PNAC who were admitted to a tertiary referral center was conducted. Patients were classified as treatment group (receiving UDCA within 14 days after onset of cholestasis) or control group (no medical treatment). Patients who received abdominal surgery were excluded.

RESULTS

A total of 30 patients were recruited, including 12 in the treatment group and 18 in the control group. The demographic data, total fasting duration, onset of cholestasis, age to tolerance of full feeds, and the duration of parenteral nutrition (PN) before the onset of cholestasis were comparable between the two groups. There was a trend in the control group to later onset of cholestasis. The patients who received UDCA therapy with doses of 10 to 30 mg/kg/day had a shorter duration of cholestasis than the control group (62.8 vs 92.4 days, P=.006). Furthermore, the peak serum levels of direct bilirubin also was significantly lower in the treatment group.

CONCLUSION

UDCA can improve the course of PNAC in VLBW infants.

Low birth weight: a possible risk factor also for liver diseases in adult life?

Birth weight is a popular topic, because it is precisely recorded, a major determinant of infant survival, associated with infant mortality, and health outcomes later in life. Low birth weight (LBW) is a predisposing factor for metabolic abnormalities such as atherosclerosis, renal disease, non-insulin diabetes mellitus, asthma, low IQ, hypertension, obesity, psychological distress. They have all been reported to be more common among those who were small at birth. Due to lack of studies suggesting a linkage between LBW and diseases of liver; evidences, which support the hypothesis on the creation of a link between LBW, an indicator of unfavourable intrauterine environment, and liver diseases emerging in the adult life, and possible direct associations of LBW with liver diseases, e.g., hepatitis, non-alcoholic fatty liver disease, cirrhosis, hepatoblastoma, or hepatocellular carcinoma were discussed. The associations between LBW and hepatitis vaccination as well as paediatric parental nutrition were also noted.