Intravenous lipid emulsions in pediatrics: time for a change?

Use of Lipids in Neonates Requiring Parenteral Nutrition

Neonates have limited antioxidative capacity and are at increased risk of infection and inflammation-a situation that is exacerbated in preterm neonates. Together, oxidative stress and inflammation are implicated in many serious conditions affecting neonates, such as bronchopulmonary dysplasia and periventricular leukomalacia. Neonates requiring parenteral nutrition have certain nutritional requirements. For example, very long-chain ω-3 polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are regarded as conditionally essential with critical roles during early retinal and brain development, and may also have other benefits such as anti-inflammatory effects. Because of these factors, the choice of lipid emulsion used as part of parenteral nutrition support may influence clinical outcomes in neonates. There are concerns that lipid emulsions based purely on soybean oil may increase lipid peroxidation, oxidative stress, and inflammation because of their high ω-6 PUFA and low ω-3 PUFA concentrations. Composite fish-oil containing lipid emulsions may provide advantages for neonates owing to their high DHA and EPA content and high antioxidant (α-tocopherol) levels. Here, we discuss clinical trials of lipid emulsions in preterm and term neonatal populations, with a particular emphasis on markers of oxidative stress and DHA and EPA levels. Olive oil/soybean oil lipid emulsions have shown few advantages in neonates over other lipid emulsions. However, compared with either pure soybean or soybean/olive-oil based emulsions, composite fish-oil containing lipid emulsions reduce oxidative stress/lipid peroxidation and also increase DHA and EPA levels. These advantages may translate into clinical benefits for neonates requiring parenteral nutrition.

Fish Oil (SMOFlipid) and olive oil lipid (Clinoleic) in very preterm neonates

OBJECTIVES

Fat emulsions used in Australia for parenteral nutrition in preterm neonates have been based on either soybean oil or olive oil (OO). OO lipid Clinoleic has a high ratio of n-6 to n-3 fatty acids (9:1); this may not be ideal for long-chain polyunsaturated fatty acids supply. Newly available SMOFlipid has an appropriate ratio of n-6 to n-3 fatty acids (2.5:1). SMOFlipid also contains OO (25%), coconut oil (30%), and soybean oil (30%). The aims of the study were to evaluate the safety of the SMOFlipid and to test the hypothesis that SMOFlipid would lead to increased omega-3 long-chain polyunsaturated fatty acid levels and reduced oxidative stress as compared with Clinoleic in preterm neonates (<30 weeks).

METHODS

Preterm neonates (23-30 weeks) were randomised to receive Clinoleic or SMOFlipid emulsion for 7 days. Investigators and outcome assessors were masked to allocation. Plasma F2-isoprostanes (lipid peroxidation marker), red blood cell fatty acids, and vitamin E were measured before and after the study. Blood culture positive sepsis and growth were monitored for safety.

RESULTS

Thirty of 34 participants completed the study. Both emulsions were well tolerated without any adverse events. F2-isoprostane levels were reduced in the SMOFlipid group as compared with baseline. Eicosapentanoic acid and vitamin E levels were significantly increased in the SMOFlipid group. Oleic acid and linoleic acid levels were increased in both groups. No significant differences were noted in poststudy docosahexaenoic acid levels in both groups despite higher levels of docosahexaenoic acid in SMOFlipid.

CONCLUSIONS

SMOFlipid was safe, well tolerated, and showed beneficial effect in terms of reduction of oxidative stress by reducing lipid peroxidation levels in high-risk preterm neonates.

Standardised parenteral nutrition

Parenteral nutrition (PN) has become an integral part of clinical management of very low birth weight premature neonates. Traditionally different components of PN are prescribed individually considering requirements of an individual neonate (IPN). More recently, standardised PN formulations (SPN) for preterm neonates have been assessed and may have advantages including better provision of nutrients, less prescription and administration errors, decreased risk of infection, and cost savings. The recent introduction of triple-chamber bag that provides total nutrient admixture for neonates may have additional advantage of decreased risk of contamination and ease of administration.

The metabolic effects of two different lipid emulsions used in parenterally fed premature infants--a randomized comparative study

OBJECTIVE

To compare the effects of two different lipid emulsions, based on soybean oil and olive oil respectively on plasma lipid concentrations and acylcarnitine profile of very low birth weight infants.

DESIGN

Randomized comparative study.

PATIENTS AND METHODS

Forty very low birth weight infants, ≤32 weeks of gestational age and receiving at least 40% of the calorie taken by parenteral nutrition from lipid solution at 14th day of life were evaluated. Group I (n=20) received soybean oil based lipid emulsion (Intralipid®) and Group II (n=20) received olive oil based lipid emulsion (Clinoleic®).

MAIN OUTCOME MEASURES

Plasma lipid concentrations and acylcarnitine profile were assessed.

RESULTS

Triglyceride, cholesterol, high and low density lipoprotein levels, liver function tests were similar between two groups whereas very low density lipoprotein level was statistically lower in Group I (p<0.05). Free carnitine levels were 15.73±10.67 in Group I and 34.25±22.18 μM in Group II (p=0.012) and hexanoyl carnitine levels 2.18±2.10 in Group I and 0.38±0.12 μM in Group II, respectively (p=0.005). Plasma medium chain acylcarnitine levels were significantly higher in Group I.

CONCLUSIONS

Low levels of very low density lipoprotein in Group I may be a way of hemostasis to keep the serum triglyceride within normal levels. Lower free carnitine levels in soybean oil-based group is the result of carnitine need during the mitochondrial transport of long chain fatty acids. In Group I, due to the inefficient transport of medium chain fatty acids into the mitochondria, medium chain acylcarnitines accumulate in plasma. This may be the reason of lower carnitine levels in Group I. We suggest that higher levels of hexanoyl carnitine, reflecting defective mitochondrial transport of hexanoyl which leads immunsupression, may be the cause of higher sepsis risk in Group I.

Short-term use of parenteral nutrition with a lipid emulsion containing a mixture of soybean oil, olive oil, medium-chain triglycerides, and fish oil: a randomized double-blind study in preterm infants

BACKGROUND

For premature neonates needing parenteral nutrition (PN), a balanced lipid supply is crucial. The authors hypothesized that a lipid emulsion containing medium-chain triglycerides (MCTs) and soybean, olive, and fish oils would be as safe and well tolerated as a soybean emulsion while beneficially influencing the fatty acid profile.

METHODS

Double-blind, controlled study in 53 neonates (<34 weeks' gestation) randomized to receive at least 7 days of PN containing either an emulsion of MCTs and soybean, olive, and fish oils or a soybean oil emulsion. Target lipid dosage was 1.0 g fat/kg body weight [BW]/d on days 1-3, 2 g/kg BW/d on day 4, 3 g/kg BW/d on day 5, and 3.5 g/kg BW/d on days 6-14.

RESULTS

Test emulsion vs control, mean ± SD: baseline triglyceride concentrations were 0.52 ± 0.16 vs 0.54 ± 0.19 mmol/L and increased similarly in both groups to 0.69 ± 0.38 vs 0.67 ± 0.36 on day 8 of treatment (P = .781 for change). A significantly higher decrease in total and direct bilirubin vs baseline was seen in the test group compared with the control group P < .05 between groups). In plasma and red blood cell phospholipids, eicosapentaenoic acid and docosahexaenoic acid were higher, and the n-6/n-3 fatty acid ratio was lower in the test group (P < .05 vs control).

CONCLUSIONS

The lipid emulsion, based on a mixture of MCTs and soybean, olive, and fish oils, was safe and well tolerated by preterm infants while beneficially modulating the fatty acid profile.

Comparison of lipid emulsions on antioxidant capacity in preterm infants receiving parenteral nutrition

BACKGROUND

Although a variety of different lipid emulsions with varying fatty acid contents have been developed, there are some concerns about the administration of these lipid emulsions because of potential adverse effects, including oxidative stress-related morbidity. The aim of the present study was to evaluate and compare the effects of the standard soybean oil-based and olive oil-based i.v. lipid emulsions (ILE) on oxidative stress, determined by total antioxidant capacity (TAC), and to investigate the safety of the use of these two emulsions in terms of biochemical indices.

METHODS

In this prospective study, premature infants were randomly assigned to two groups, each group consisting of 32 patients who received parenteral ILE of either 20% olive oil or 20% soybean oil. They were given ILE for 7 days and then were evaluated with regard to TAC.

RESULTS

No statistically significant difference was observed between the groups in terms of routine biochemical parameters. TAC for both groups on day 7 was significantly lower compared with that on day 0. Although the decrease in TAC within 7 days of ILE administration was greater in the soybean group compared with that in the olive oil group, it was not statistically significant.

CONCLUSIONS

Olive oil-based ILE exhibit similar antioxidant activity and can be used as an alternative to soybean oil-based ILE. TAC significantly decreased in infants following administration of either lipid emulsion, and premature infants tolerated either ILE well, both biochemically and clinically.

Neonatology/Paediatrics - Guidelines on Parenteral Nutrition, Chapter 13

There are special challenges in implementing parenteral nutrition (PN) in paediatric patients, which arises from the wide range of patients, ranging from extremely premature infants up to teenagers weighing up to and over 100 kg, and their varying substrate requirements. Age and maturity-related changes of the metabolism and fluid and nutrient requirements must be taken into consideration along with the clinical situation during which PN is applied. The indication, the procedure as well as the intake of fluid and substrates are very different to that known in PN-practice in adult patients, e.g. the fluid, nutrient and energy needs of premature infants and newborns per kg body weight are markedly higher than of older paediatric and adult patients. Premature infants <35 weeks of pregnancy and most sick term infants usually require full or partial PN. In neonates the actual amount of PN administered must be calculated (not estimated). Enteral nutrition should be gradually introduced and should replace PN as quickly as possible in order to minimise any side-effects from exposure to PN. Inadequate substrate intake in early infancy can cause long-term detrimental effects in terms of metabolic programming of the risk of illness in later life. If energy and nutrient demands in children and adolescents cannot be met through enteral nutrition, partial or total PN should be considered within 7 days or less depending on the nutritional state and clinical conditions.

Parenteral lipid emulsions based on olive oil compared with soybean oil in preterm (<28 weeks' gestation) neonates: a randomised controlled trial

BACKGROUND

: New olive oil-based (OL) lipid emulsions (olive:soy oil = 4:1) have lower polyunsaturated fatty acid (PUFA) (20% vs 60%) and higher vitamin E content (an antioxidant) compared with traditional soybean oil (SO) emulsions.

OBJECTIVE

: Compare efficacy and safety of OL with SO emulsions in preterm neonates (<28 weeks) at high risk for oxidative stress.

PATIENTS AND METHODS

: Preterm neonates (gestation 23-<28 weeks) were randomised to receive OL or SO emulsion for 5 days using a standard protocol in a tertiary perinatal centre (King Edward Memorial Hospital for Women, Perth, Western Australia). Investigators and outcome assessors were masked to allocation. Plasma F2-isoprostanes (lipid peroxidation marker), plasma, and red blood cell fatty acids were measured before and after the study. Safety was monitored by liver function tests.

RESULTS

: Forty-four of 50 participants (OL-23, SO-21) completed the study. Both emulsions were well tolerated with no significant adverse events. F2-isoprostane levels were comparable at baseline and study end. Oleic and linoleic acid levels were significantly high on day 6 in OL and SO groups, respectively. Long-chain PUFA levels were similar between groups despite the lower PUFA content of OL. The olive oil-based group had significantly higher levels of C18:4n-3, suggesting Delta6-desaturase enzyme inhibition in the SO group.

CONCLUSIONS

: Olive oil-based emulsion was safe and well tolerated by preterm neonates. Similar long-chain PUFA levels were achieved in the OL group despite significantly lower amount of PUFA content; however, there was no difference in lipid peroxidation (F2-isoprostane levels). Large trials are needed to confirm these benefits.

Enhancing parenteral nutrition therapy for the neonate

The neonate receiving parenteral nutrition (PN) therapy requires a physiologically appropriate solution in quantity and quality given according to a timely, cost-effective strategy. Maintaining tissue integrity, metabolism, and growth in a neonate is challenging. To support infant growth and influence subsequent development requires critical timing for nutrition assessment and intervention. Providing amino acids to neonates has been shown to improve nitrogen balance, glucose metabolism, and amino acid profiles. In contrast, supplying the lipid emulsions (currently available in the United States) to provide essential fatty acids is not the optimal composition to help attenuate inflammation. Recent investigations with an omega-3 fish oil IV emulsion are promising, but there is need for further research and development. Complications from PN, however, remain problematic and include infection, hepatic dysfunction, and cholestasis. These complications in the neonate can affect morbidity and mortality, thus emphasizing the preference to provide early enteral feedings, as well as medication therapy to improve liver health and outcome. Potential strategies aimed at enhancing PN therapy in the neonate are highlighted in this review, and a summary of guidelines for practical management is included.

In vivo and in vitro properties of an intravenous lipid emulsion containing only medium chain and fish oil triglycerides

BACKGROUND & AIMS

The triglyceride (TG) fatty acyl composition in lipid emulsions influences their metabolism. Little is known about the effects of long chain omega-3 polyunsaturated fatty acids (PUFA) on lipid emulsion metabolism. We investigated possible differences between omega-3 containing emulsions in their metabolism and tissue-targeting in vivo in a mouse model, and in vitro using lipolysis and cell culture experiments.

METHODS

Soy oil (LCT), MCT/LCT/omega-3 (5:4:1, wt/wt/wt), and MCT/omega-3 (8:2, wt/wt) emulsions were radiolabeled with nondegradable 1alpha,2alpha (n)-[3H] cholesteryl oleoyl ether to trace core particle metabolism in C57BL/6J mice following a bolus injection. Blood samples obtained over 25 min and extracted organs were used to measure the tissue distribution of lipid emulsion particles. Lipoprotein lipase (LpL)-mediated hydrolysis experiments and cell uptake studies in cultured J774 murine macrophages were also performed.

RESULTS

Blood clearance of 8:2 was 13.4% and 29.8% faster compared to 5:4:1 and LCT, respectively. LCT had greatest liver uptake. LpL-mediated hydrolysis was greatest in 8:2 and lowest in LCT. Overall, cell TG accumulation in the presence of apolipoprotein E was least with 8:2.

CONCLUSIONS

Our data shows that 8:2 had the most efficient blood clearance but less hepatic uptake in vivo. In vitro, 8:2 had both highest hydrolysis by LpL and intracellular TG utilization in the presence of apoE. Thus, an 8:2 lipid emulsion undergoes efficient blood clearance and may direct omega-3 PUFA more towards extrahepatic tissues.