Structured Triglyceride Emulsions in Parenteral Nutrition

Synthesis of middle-long-middle structured intralipids by biological catalysis and the evaluation of intralipids' protective effect on liver injury rats

Intralipids are widely used to provide energy and necessary fatty acids for the patients. The structure of lipids may affect their function. We developed a bio-catalyzed route to prepare various intralipids and investigated the protective effect of intralipids against α-naphthylisothiocyanate (ANIT) induced liver injury rats, further discussing the structure-function relationship. The middle-long-middle (MLM) structural intralipid was synthesized through alcoholysis-esterification, and the influence factors were investigated. ANIT treatment caused liver injury, further making hepatocyte damage, and increasing related biochemical indexes, like aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), and total bilirubin (TBIL). Especially, MLM-based and structoglyceride (STG) intralipids worked better in the early stage, to reduce the AST, ALT, and TBIL (p < .05). MLM showed a comparative advantage over other intralipids to accelerate the reduction of ALT (1st day) and AST (3rd day). MLM intralipid might be a promising next-generation intralipid than the current STG intralipid liver-injury patients. The biological catalysis MLM-based intralipids can make the maximum utilization of fatty acids for the liver regeneration, where middle-chain fatty acid (MCFA) in sn-1,3 position can be metabolized directly to provide energy and long-chain fatty acid (LCFA) in sn-2 position can be delivered effectively for cell membrane repairing.

New perspective toward nutritional support for malnourished cancer patients: Role of lipids

To improve the difficulties related to malnutrition, nutritional support has become an essential part of multidisciplinary comprehensive treatment for cancer. Lipids are essential nutrient source for the human body, and nowadays in clinical practices, it has a positive interventional effect on patients suffering from cancer. However, contribution of lipids in nutritional support of cancer patients is still poorly understood. Moreover, the sensory and physicochemical properties of lipids can severely restrict their applications in lipid-rich formula foods. In this review article, for the first time, we have presented a summary of the existing studies which were related to the associations between different lipids and improved malnutrition in cancer patients and discussed possible mechanisms. Subsequently, we discussed the challenges and effective solutions during processing of lipids into formula foods. Further, by considering existing problems in current lipid nutritional support, we proposed a novel method for the treatment of malnutrition, including developing individualized lipid nutrition for different patients depending on the individual's genotype and enterotype. Nonetheless, this review study provides a new direction for future research on nutritional support and the development of lipid-rich formula foods for cancer patients, and probably will help to improve the efficacy of lipids in the treatment of cancer malnutrition.

Composition and Functionality of Lipid Emulsions in Parenteral Nutrition: Examining Evidence in Clinical Applications

Lipid emulsions (LEs), an integral component in parenteral nutrition (PN) feeding, have shifted from the primary aim of delivering non-protein calories and essential fatty acids to defined therapeutic outcomes such as reducing inflammation, and improving metabolic and clinical outcomes. Use of LEs in PN for surgical and critically ill patients is particularly well established, and there is enough literature assigning therapeutic and adverse effects to specific LEs. This narrative review contrarily puts into perspective the fatty acid compositional (FAC) nature of LE formulations, and discusses clinical applications and outcomes according to the biological function and structural functionality of fatty acids and co-factors such as phytosterols, α-tocopherol, emulsifiers and vitamin K. In addition to soybean oil-based LEs, this review covers clinical studies using the alternate LEs that incorporates physical mixtures combining medium- and long-chain triglycerides or structured triglycerides or the unusual olive oil or fish oil. The Jaded score was applied to assess the quality of these studies, and we report outcomes categorized as per immuno-inflammatory, nutritional, clinical, and cellular level FAC changes. It appears that the FAC nature of LEs is the primary determinant of desired clinical outcomes, and we conclude that one type of LE alone cannot be uniformly applied to patient care.

Meta-analysis of the efficacy and safety of structured triglyceride lipid emulsions in parenteral nutrition therapy in China

BACKGROUND & AIMS

We performed a meta-analysis of data from recent studies to evaluate the safety and efficacy of parenteral nutrition (PN) with structured triglyceride (STG) lipid emulsions compared to medium-chain triglyceride (MCT)/long-chain triglyceride (LCT) lipid emulsions in Chinese patients.

METHODS

PubMed, Embase, Cochrane Library, China National Knowledge Internet, Wanfang, and VIP were searched for randomized controlled trials comparing STGs with MCTs/LCTs published in English or Chinese between January 1987 and October 2017. Two independent investigators screened and selected studies according to prespecified selection criteria. Data were pooled and analysed using RevMan^® version 5.3.

RESULTS

Thirty-two studies comprising 1944 patients were included in the meta-analysis. Compared with MCT/LCT emulsions, STGs resulted in a shorter hospital length of stay (LOS) (weighted mean difference [WMD], -1.65 days; 95% confidence interval [CI]: -2.63, -0.67; P = 0.001) and lower adverse event rates (relative risk, 0.64; 95% CI: 0.48, 0.85; P = 0.002). STGs were associated with a significantly better cumulative nitrogen balance (WMD, 4.04 g/24 h; 95% CI: 3.10, 4.97; P < 0.0001) as well as higher concentrations of pre-albumin (WMD 35.20 mg/L; 95% CI: 26.59, 43.81; P < 0.0001) and albumin (WMD, 1.64 g/L; 95% CI: 1.17, 2.10; P < 0.0001) compared with MCTs/LCTs. In contrast, significantly lower concentrations of plasma triglycerides (WMD, -0.21 mmol/L; 95% CI: -0.30, -0.12; P < 0.0001), total cholesterol (WMD, -0.45 mmol/L; 95% CI: -0.60, -0.29; P < 0.0001), alanine aminotransferase (WMD, -7.68 IU/L; 95% CI: -9.68, -5.68; P < 0.0001) and aspartate aminotransferase (WMD, -10.27 IU/L; 95% CI: -16.05, -4.49; P = 0.0005) were observed in patients receiving STGs compared with MCT/LCTs. STGs were also associated with reduced inflammation and improved immunological function, as reflected by significantly lower C-reactive protein concentrations (WMD, -2.67 mg/L; 95% CI: -4.55, -0.79; P = 0.005) and increased concentrations of IgG (WMD, 2.11 g/L; 95% CI: 0.23, 3.99; P = 0.03), IgA (WMD, 0.21 g/L; 95% CI: 0.14, 0.28; P < 0.0001), CD3+ (WMD, 5.81%; 95% CI: 0.92, 10.70; P = 0.02), and CD4+/CD8+ (WMD, 0.12; 95% CI: 0.00, 0.24; P = 0.04) compared with MCT/LCTs.

CONCLUSIONS

Administration of STGs was shown to improve hepatic function, nutrition status, and immunological function and reduce inflammation, LOS, and adverse events compared with MCT/LCTs in Chinese patients receiving PN.

Meta-Analysis of Structured Triglyceride versus Physical Mixture Medium- and Long-Chain Triglycerides for PN in Liver Resection Patients

BACKGROUND

The use of total parenteral nutrition can affect liver function, causing a series of problems such as cholestasis. The aim of this meta-analysis was to compare structured triglyceride- (STG-) based lipid emulsions with physical medium-chain triglyceride (MCT)/long-chain triglyceride (LCT) mixtures in patients who had undergone liver surgery to identify any differences between these two types of parenteral nutrition.

METHODS

We searched the databases of PubMed, the Cochrane Library, Web of Science, EMBASE, and Chinese Biomedicine Database from January 2007 to March 2017 and included studies that compared STG-based lipid emulsions with physical MCT/LCT mixtures for surgical patients with liver disease.

CONCLUSION

The STG was more beneficial than physical MCT/LCT on recovery of liver function and immune function. Therefore, STGs may represent a promising alternative to other types of lipid emulsions for hepatic surgery patients.

De novo fatty acid biosynthesis and elongation in very long-chain acyl-CoA dehydrogenase-deficient mice supplemented with odd or even medium-chain fatty acids

An even medium-chain triglyceride (MCT)-based diet is the mainstay of treatment in very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency (VLCADD). Previous studies with magnetic resonance spectroscopy have shown an impact of MCT on the average fatty acid chain length in abdominal fat. We therefore assume that medium-chain fatty acids (MCFAs) are elongated and accumulate in tissue as long-chain fatty acids. In this study, we explored the hepatic effects of long-term supplementation with MCT or triheptanoin, an odd-chain C7-based triglyceride, in wild-type and VLCAD-deficient (VLCAD(-/-) ) mice after 1 year of supplementation as compared with a control diet. The de novo biosynthesis and elongation of fatty acids, and peroxisomal β-oxidation, were quantified by RT-PCR. This was followed by a comprehensive analysis of hepatic and cardiac fatty acid profiles by GC-MS. Long-term application of even and odd MCFAs strongly induced de novo biosynthesis and elongation of fatty acids in both wild-type and VLCAD(-/-) mice, leading to an alteration of the hepatic fatty acid profiles. We detected de novo-synthesized and elongated fatty acids, such as heptadecenoic acid (C17:1n9), eicosanoic acid (C20:1n9), erucic acid (C22:1n9), and mead acid (C20:3n9), that were otherwise completely absent in mice under control conditions. In parallel, the content of monounsaturated fatty acids was massively increased. Furthermore, we observed strong upregulation of peroxisomal β-oxidation in VLCAD(-/-) mice, especially when they were fed an MCT diet. Our data raise the question of whether long-term MCFA supplementation represents the most efficient treatment in the long term. Studies on the hepatic toxicity of triheptanoin are still ongoing.

Perioperative nutritional support and fluid therapy in patients with liver diseases

The prevalence of liver dysfunction and malnutrition is common among patients with obstructive jaundice or cirrhosis, the poor nutrition status in patients with indications for hepatic resection increases the risk of postoperative complications and/or mortality. Hepatic surgery significantly affects body's metabolism and environment. Therefore, it is very important for patients with liver diseases undergoing hepatic surgery to receive essential nutritional support and fluid therapy during perioperative period. There are several principles in nutritional support and fluid therapy that surgeons need to pay attention to, for example, time, nutritional approach, fluid volume, choice of fat emulsions and amino acids. Some issues, such as albumin and plasma application, choice of crystalloid and colloid, liver protective therapy, also need further attention.

Lipid emulsions in parenteral nutrition: current applications and future developments

INTRODUCTION

A parenteral lipid emulsion (LE), used as a key source of energy, essential fatty acids (FAs), and fat-soluble vitamins, is an integral part of a parenteral nutrition (PN) regimen. The conventional LEs, such as soybean oil (SO)-based emulsions, have caused concerns about the potential adverse effects involving oxidative stress, inflammation, and immune response probably because of undesirable FA composition.

AREAS COVERED

Recently, alternative LEs, optimizing the FA composition with partial substitution of SO with medium-chain triglyceride (MCT), olive oil (OO), and fish oil (FO), have been developed and applied in clinical practice. This review summarizes the characteristics and beneficial clinical effects of alternative parenteral LEs in critically ill, pediatric, and long-term PN patients.

EXPERT OPINION

More clinical data from sufficiently high-powered studies are required to characterize the integral biological properties of alternative LEs for further selection to fit individual needs and disease characteristics. Simultaneously, potential lipid sources with desirable FA compositions and biological properties should be selected to develop new therapeutic LEs. As supplements to current parenteral lipids, the new LEs with different therapeutic effects are expected to fit specified subpopulations of patients with different diseases. Great efforts should be devoted to the development of parenteral LEs.

The optimal lipid formulation in enteral feeding in critical illness: clinical update and review of the literature

Suitable and timely early enteral nutrition is paramount to providing optimal patient care for the critically ill. Lipids serve many essential roles throughout the human body, and are important components of most enteral formulations. This paper reviews lipid structure, function, and optimal utility for this macronutrient in enteral feeds. The use of omega-3 fatty acids has become common in critical care formulations, and their clinical efficacy is outlined separately. Available evidence is reviewed, and future directions are discussed.

Injectable lipid emulsions-advancements, opportunities and challenges

Injectable lipid emulsions, for decades, have been clinically used as an energy source for hospitalized patients by providing essential fatty acids and vitamins. Recent interest in utilizing lipid emulsions for delivering lipid soluble therapeutic agents, intravenously, has been continuously growing due to the biocompatible nature of the lipid-based delivery systems. Advancements in the area of novel lipids (olive oil and fish oil) have opened a new area for future clinical application of lipid-based injectable delivery systems that may provide a better safety profile over traditionally used long- and medium-chain triglycerides to critically ill patients. Formulation components and process parameters play critical role in the success of lipid injectable emulsions as drug delivery vehicles and hence need to be well integrated in the formulation development strategies. Physico-chemical properties of active therapeutic agents significantly impact pharmacokinetics and tissue disposition following intravenous administration of drug-containing lipid emulsion and hence need special attention while selecting such delivery vehicles. In summary, this review provides a broad overview of recent advancements in the field of novel lipids, opportunities for intravenous drug delivery, and challenges associated with injectable lipid emulsions.

Recent advances in the management of intestinal failure-associated liver disease

PURPOSE OF REVIEW

To summarize the current management of intestinal failure-associated liver disease (IFALD) by reviewing recent advances in our understanding of the condition and the effects of different therapeutic approaches.

RECENT FINDINGS

The importance of gastrointestinal length and continuity in the aetiology and treatment of IFALD has been demonstrated in both retrospective and interventional cohorts. A mechanism for the cholestatic effect of soy-based lipid has been described, and the clinical use of alternative lipid sources has demonstrated benefit. Prevention of IFALD has been shown with the use of erythromycin in neonates, and reversal of established IFALD has been demonstrated with isolated intestinal transplantation.

SUMMARY

A greater understanding of the mechanisms of IFALD has led to promising interventions to prevent and treat the condition. Other possible therapeutic targets require more formal evaluation, and further work is required to develop noninvasive tools for the assessment and prognosis of IFALD that will guide treatment and help in the selection of patients and timing of transplantation.

Effects of parenteral structured lipid emulsion on modulating the inflammatory response in rats undergoing a total gastrectomy

OBJECTIVES

Structured lipid emulsion improves the nitrogen balance and is rapidly cleared from the blood of moderately catabolic patients. However, the effects of structured lipids on inflammatory reactions during major surgery are not clear. This study investigated the effect of a parenteral structured triacylglycerol emulsion on leukocyte adhesion molecule expression and inflammatory mediator production in rats undergoing a total gastrectomy.

METHODS

Normal rats with internal jugular catheters were assigned to three experimental groups and received total parenteral nutrition. At the same time, a total gastrectomy was performed on the experimental groups. The total parenteral nutrition solutions were isonitrogenous and identical in nutrient compositions except for differences in the composition of the fat emulsion. Group 1 received a conventional fat emulsion with long-chain triacylglycerols (LCTs), group 2 received a physical mixture of medium-chain triacylglycerols (MCTs) and LCTs (MCT/LCT), and group 3 received structured lipids composed of MCTs and LCTs (STG). Half of the rats in each respective group were sacrificed 1 d and the other half 3 d after surgery to examine the analytical parameters.

RESULTS

Plasma cholesterol and free fatty acid levels in the STG group were lower than those in the other groups after surgery. The STG group had lower leukocyte CD11a/CD18 expressions than the MCT/LCT group 3 d after surgery, and CD11b/CD18 expressions in the STG group were lower than those in the LCT group on postoperative days. The STG group had higher monocyte chemotactic protein-1 and macrophage inflammatory protein-2 levels in peritoneal lavage fluid than did the other two groups.

CONCLUSION

These results suggest that, compared with the LCT and MCT/LCT groups, rats administered STG had lower plasma lipid concentrations and leukocyte integrin expressions. In addition, STG administration may cause increased recruiting of neutrophils and monocytes at the site of injury and enhance antipathogenicity in rats undergoing a total gastrectomy.

Immune modulation by parenteral lipid emulsions

Total parenteral nutrition is the final option for nutritional support of patients with severe intestinal failure. Lipid emulsions constitute the main source of fuel calories and fatty acids (FAs) in parenteral nutrition formulations. However, adverse effects on patient outcomes have been attributed to the use of lipids, mostly in relation to impaired immune defenses and altered inflammatory responses. Over the years, this issue has remained in the limelight, also because technical advances have provided no safeguard against the most daunting problems, ie, infectious complications. Nevertheless, numerous investigations have failed to produce a clear picture of the immunologic characteristics of the most commonly used soybean oil-derived lipid emulsions, although their high content of n-6 polyunsaturated FAs (PUFAs) has been considered a drawback because of their proinflammatory potential. This concern initiated the development of emulsions in which part of the n-6 FA component is replaced by less bioactive FAs, such as coconut oil (rich in medium-chain saturated FAs) or olive oil (rich in the n-9 monounsaturated FA oleic acid). Another approach has been to use fish oil (rich in n-3 PUFA), the FAs of which have biological activities different from those of n-6 PUFAs. Recent studies on the modulation of host defenses and inflammation by fish-oil emulsions have yielded consistent data, which indicate that these emulsions may provide a tool to beneficially alter the course of immune-mediated conditions. Although most of these lipids have not yet become available on the US market, this review synthesizes available information on immunologic characteristics of the different lipids that currently can be applied via parenteral nutrition support.