Kathleen M. Gura

Safety and Efficacy of a Fish-Oil–Based Fat Emulsion in the Treatment of Parenteral Nutrition–Associated Liver Disease

BACKGROUND. Parenteral nutrition–associated liver disease can be a progressive and fatal entity in children with short-bowel syndrome. Soybean-fat emulsions provided as part of standard parenteral nutrition may contribute to its pathophysiology. METHODS. We compared safety and efficacy outcomes of a fish-oil–based fat emulsion in 18 infants with short-bowel syndrome who developed cholestasis (serum direct bilirubin level of >2 mg/dL) while receiving soybean emulsions with those from a historical cohort of 21 infants with short-bowel syndrome who also developed cholestasis while receiving soybean emulsions. The primary end point was time to reversal of cholestasis (3 consecutive measurements of serum direct bilirubin level of ≤2 mg/dL). RESULTS. Among survivors, the median time to reversal of cholestasis was 9.4 and 44.1 weeks in the fish-oil and historical cohorts, respectively. Subjects who received fish-oil–based emulsion experienced reversal of cholestasis 4.8 times faster than those who received soybean emulsions and 6.8 times faster in analysis adjusted for baseline bilirubin concentration, gestational age, and the diagnosis of necrotizing enterocolitis. A total of 2 deaths and 0 liver transplantations were recorded in the fish-oil cohort and 7 deaths and 2 transplantations in the historical cohort. The provision of fish-oil–based fat emulsion was not associated with essential fatty acid deficiency, hypertriglyceridemia, coagulopathy, infections, or growth delay. CONCLUSIONS. Parenteral fish-oil–based fat emulsions are safe and may be effective in the treatment of parenteral nutrition–associated liver disease.

Reversal of Parenteral Nutrition–Associated Liver Disease in Two Infants With Short Bowel Syndrome Using Parenteral Fish Oil: Implications for Future Management

Here we report the reversal of cholestasis in 2 infants with intestinal failure and parenteral nutrition–associated liver disease. Treatment involved the substitution of a conventional intravenous fat emulsion with one containing primarily omega-3 fatty acids. Biochemical tests of liver function improved significantly. One child was removed from the liver transplantation list because of improved hepatic function, and the second child had complete resolution of cholestasis while solely on parenteral nutrition. This suggests that fat emulsions made from fish oils may be an effective means of treating and preventing this often-fatal condition. A randomized, controlled trial is necessary to study the efficacy of this new approach to parenteral nutrition–associated liver disease.

Parenteral Fish Oil Improves Outcomes in Patients with Parenteral Nutrition Associated Liver Injury

Objective:The objective was to determine the safety and efficacy of a fish oil-based intravenous lipid emulsion (ILE) in the treatment of parenteral nutrition-associated liver disease (PNALD). Summary and Background Data:PNALD can be a lethal complication in children with short bowel syndrome (SBS). ILE based on soybean oil administered with parenteral nutrition (PN) may contribute to its etiology. Methods:We performed an open-labeled trial of a fish oil-based ILE in 42 infants with SBS who developed cholestasis (serum direct bilirubin >2 mg/dL) while receiving soybean oil-based ILE. Safety and efficacy outcomes were compared with those from a contemporary cohort of 49 infants with SBS and cholestasis whose PN course included soybean ILE only. The primary efficacy end-point was time to reversal of cholestasis (direct bilirubin ≤2 mg/dL). Results:Three deaths and 1 liver transplantation occurred in the fish oil cohort, compared with 12 deaths and 6 transplants in the soybean oil cohort (P = 0.005). Among survivors not transplanted during PN, cholestasis reversed while receiving PN in 19 of 38 patients in the fish oil cohort versus 2 of 36 patients in the soybean oil cohort. Based on Cox models, subjects receiving fish oil-based ILE experienced reversal of cholestasis 6 times faster (95% CI: 2.0–37.3) than those receiving soybean oil-based ILE. The provision of fish oil-based ILE was not associated with hypertriglyceridemia, coagulopathy, or essential fatty acid deficiency. Moreover, hypertriglyceridemic events and abnormal international normalized ratio levels were more common among controls. Conclusions:Fish oil-based ILE is safe, may be effective in treating PNALD, and may reduce mortality and organ transplantation rates in children with SBS.

Omega-3 fatty acid supplementation prevents hepatic steatosis in a murine model of nonalcoholic fatty liver disease.

Prolonged use of total parenteral nutrition can lead to nonalcoholic fatty liver disease, ranging from hepatic steatosis to cirrhosis and liver failure. It has been demonstrated that omega-3 fatty acids are negative regulators of hepatic lipogenesis and that they can also modulate the inflammatory response in mice. Furthermore, they may attenuate hepatic steatosis even in leptin-deficient ob/ob mice. We hypothesized that omega-3 fatty acid supplementation may protect the liver against hepatic steatosis in a murine model of parenteral nutrition in which all animals develop steatosis and liver enzyme disturbances. For testing this hypothesis, groups of mice received a fat-free, high-carbohydrate liquid diet ad libitum for 19 d with enteral or i.v. supplementation of an omega-3 fatty acid emulsion or a standard i.v. lipid emulsion. Control mice received food alone or the fat-free, high-carbohydrate diet without lipid supplementation. Mice that received the fat-free, high-carbohydrate diet only or supplemented with a standard i.v. lipid emulsion developed severe liver damage as determined by histology and magnetic resonance spectroscopy as well as elevation of serum liver function tests. Animals that received an i.v. omega-3 fatty acid emulsion, however, showed only mild deposits of fat in the liver, whereas enteral omega-3 fatty acids prevented hepatic pathology and led to normalization of liver function tests. In conclusion, whereas standard i.v. lipid emulsions fail to improve dietary-induced steatotic injury to the liver, i.v. supplementation of omega-3 fatty acids partially and enteral supplementation completely protects the liver against such injury.

Efficacy of ethanol locks in reducing central venous catheter infections in pediatric patients with intestinal failure

PURPOSE We sought to determine whether a regimen of 70% ethanol locks could reduce the rate of central venous catheter (CVC) infections in parenteral nutrition-dependent children with intestinal failure. METHODS We performed a retrospective review of 23 parenteral nutrition-dependent children in our multidisciplinary intestinal rehabilitation clinic who started ethanol lock therapy between September 2007 and June 2009. The treatment regimen consisted of a 70% ethanol lock instilled 3 times per week in each catheter lumen. The rate of CVC infections before and after initiation of ethanol lock therapy was compared using the Wilcoxon signed ranks test with significance set at P < .05. RESULTS The most common diagnoses leading to intestinal failure were necrotizing enterocolitis (26.1%), gastroschisis (21.7%), and intestinal atresia (14.3%). Ethanol locks were well tolerated with no reported adverse side effects. The infection rate decreased from 9.9 per 1000 catheter days prior to initiation of ethanol locks to 2.1 per 1000 catheter days during therapy (P = .03). CONCLUSIONS A regimen of ethanol lock therapy administered three days per week appears to be a safe and effective means of reducing the rate of CVC infections in parenteral nutrition-dependent children with intestinal failure.

A.S.P.E.N. Position Paper Clinical Role for Alternative Intravenous Fat Emulsions

The currently available, standard soybean oil (SO)-based intravenous fat emulsions (IVFEs) meet the needs of most parenteral nutrition (PN) patients. There are alternative oil-based fat emulsions, such as medium-chain triglycerides (MCTs), olive oils (OOs), and fish oils (FOs), that, based on extensive usage in Europe, have an equivalent safety profile to SO. These alternative IVFEs are metabolized via different pathways, which may lead to less proinflammatory effects and less immune suppression. These alternative oil-based IVFEs are not currently available in the United States. Many patients who require IVFEs are already in a compromised state. Such patients could potentially have better clinical outcomes when receiving one of the alternative IVFEs to diminish the intake of the potentially proinflammatory ω-6 fatty acid-linoleic acid-which comprises more than 50% of the fatty acid profile in SO. Further research is needed on these alternative oil-based IVFEs to identify which IVFE oils or which combination of oils may be most clinically useful for specific patient populations.

The essentiality of arachidonic acid and docosahexaenoic acid.

OBJECTIVE The purpose of this review is to correlate the clinical finding that patients receiving parenteral nutrition with a fish oil-based lipid emulsion do not develop essential fatty acid deficiency (EFAD) with an experimental murine model, thus showing that arachidonic acid (AA) and docosahexaenoic acid (DHA) are likely to be the essential fatty acids. BACKGROUND Conventional belief is that linoleic acid (LA, omega-6) and alpha-linolenic acid (ALA, omega-3) are the essential fatty acids (EFAs). We have shown that a fish oil-based lipid emulsion containing AA (omega-6) and docosahexaenoic acid (omega-3) and insignificant quantities of LA and ALA is efficacious in the treatment of parenteral nutrition-associated liver disease (PNALD), a major cause of liver-related morbidity and mortality. The prospect of using a fish oil-based lipid emulsion as monotherapy has raised concerns of EFAD development, hindering its adoption into clinical practice. DESIGN Data from patients in our institution who received PN with a fish oil-based lipid emulsion was reviewed for clinical and biochemical evidence of EFAD, defined as an elevated triene-tetraene ratio (Mead acid/AA>0.2). We also investigated the minimum amount of fish oil required to prevent EFAD in a murine model and determined whether DHA and AA alone can prevent EFAD. RESULTS No patients receiving PN with a fish oil-based lipid emulsion in our institution have developed biochemical or clinical evidence of EFAD such as an elevated triene-tetraene ratio, growth retardation or dermatitis. This observation parallels our previously published animal studies, which demonstrated prevention of EFAD when 13% of total calories were from fish oil. Moreover, current work in our laboratory shows that AA and DHA provision alone is sufficient to prevent biochemical and physiologic evidence of EFAD in a murine model. CONCLUSIONS When dosed appropriately, fish oil-based lipid emulsions contain sufficient EFAs to prevent EFAD. Furthermore, AA and DHA alone may be the true EFAs.

Current Clinical Applications of Ω-6 and Ω-3 Fatty Acids

BACKGROUND Recent years have brought a resurgence of research interest in fatty acids, with studied fields running the gamut of human disease. This movement has run in parallel with an increased interest in using nutrition modalities as therapeutic measures, as opposed to their conventional role as energy sources. The aim of this manuscript is to provide a basic review of current clinical applications of ω-6 and ω-3 fatty acids, with a particular focus on the latter. METHODS A selective review of the voluminous literature, including randomized controlled trials, meta-analyses, population studies, and case reports, was used to compile data and identify trends in pertinent clinical applications of fatty acid therapy. CONCLUSIONS There are a myriad of disorders and maladies that seem to benefit from fatty acid supplementation, specifically ω-3 fatty acids. It has clearly been shown that ω-3 fatty acid supplementation provides a protective benefit in heart disease, and in particular sudden cardiac death. Rheumatoid arthritis (RA) is another disease entity that has been proven to benefit from this nutrition intervention, with improvement in symptoms and diminished nonsteroidal antiinflammatory drug (NSAID) usage. In addition, many psychiatric disorders, particularly schizophrenia and major depressive disorder (MDD), have shown positive results when supplementation has been used as an adjunct to standard pharmacotherapy. The remainder of clinical applications for ω-3 fatty acids requires further investigation. Specifically, according to preliminary clinical evidence, parenteral administration of fatty acids warrants further study.

Parenteral Fish Oil as Monotherapy Prevents Essential Fatty Acid Deficiency in Parenteral Nutrition Dependent Patients

Objective: The use of fish oil–based emulsions as the sole source of fat for patients receiving parenteral nutrition (PN) has raised concerns for the development of essential fatty acid deficiency (EFAD), hindering its adoption into clinical practice. The purpose of the present study was to examine fatty acid profiles of patients receiving no enteral energy, while completely dependent on PN and an intravenous fish oil–based lipid emulsion, for onset of EFAD and maintenance of growth. Patients and Methods: Prospectively collected data from 10 patients were reviewed for evidence of EFAD, defined as a triene:tetraene ratio >0.2. Gestational age–adjusted z scores for length, growth, and head circumference at baseline were compared with the corresponding z scores at time of censoring. All of the patients received PN with a fish oil–based lipid emulsion at 1 g · kg−1 · day−1 as the sole source of fat energy for at least 1 month. The fish oil monotherapy was used under a compassionate use protocol. Results: Median gestational age at the time of birth was 35 weeks, and median age at the start of treatment was 3.5 months. After a median time of 3.8 months on exclusive PN and fish oil–based lipid emulsion, none of the patients developed biochemical or clinical evidence of EFAD. z scores were not statistically different, indicating no growth impairment. Median direct bilirubin levels improved in 9 patients from 6.8 to 0.9 mg/dL (P = 0.009). Conclusions: When dosed appropriately, fish oil–based lipid emulsions contain sufficient amounts of essential fatty acids to prevent EFAD and sustain growth in patients who are completely dependent on PN.

A.S.P.E.N. Clinical Guidelines: Nutrition Support of Neonatal Patients at Risk for Necrotizing Enterocolitis

BACKGROUND Necrotizing enterocolitis (NEC) is one of the most devastating diseases in the neonatal population, with extremely low birth weight and extremely preterm infants at greatest risk. METHOD A systematic review of the best available evidence to answer a series of questions regarding nutrition support of neonates at risk of NEC was undertaken and evaluated using concepts adopted from the Grading of Recommendations, Assessment, Development and Evaluation working group. A consensus process was used to develop the clinical guideline recommendations prior to external and internal review and approval by the A.S.P.E.N. Board of Directors. RESULTS/ CONCLUSIONS: (1) When and how should feeds be started in infants at high risk for NEC? We suggest that minimal enteral nutrition be initiated within the first 2 days of life and advanced by 30 mL/kg/d in infants ≥ 1, 000 g. (Weak) (2) Does the provision of mothers milk reduce the risk of developing NEC? We suggest the exclusive use of mothers milk rather than bovine-based products or formula in infants at risk for NEC. (Weak) (3) Do probiotics reduce the risk of developing NEC? There are insufficient data to recommend the use of probiotics in infants at risk for NEC. (Further research needed.) (4) Do nutrients either prevent or predispose to the development of NEC? We do not recommend glutamine supplementation for infants at risk for NEC (Strong). There is insufficient evidence to recommend arginine and/or long chain polyunsaturated fatty acid supplementation for infants at risk for NEC. (Further research needed.) (5) When should feeds be reintroduced to infants with NEC? There are insufficient data to make a recommendation regarding time to reintroduce feedings to infants after NEC. (Further research needed.).