Lipids in the nutritional support of the critically ill patients

[Research advances in the effect of long-chain polyunsaturated fatty acids on neonates]

Adequate supply of long-chain polyunsaturated fatty acids (LCPUFAs) is of great importance for neonates, especially preterm infants. In particular, n-3 LCPUFAs and n-6 LCPUFAs play a key role in brain development, immune regulation, and disease prevention. Lack of LCPUFAs may lead to neurodevelopmental impairment, affect the development of neonatal immune system, and result in neonatal diseases. This article reviews related research advances in the physiological function of LCPUFAs and its effect on neonates, so as to provide reference for clinical application.

Home parenteral nutrition patients on mixed oil lipid emulsion have a higher rate of hospitalizations compare to those on soybean oil- a prospective 2-year cohort study

BACKGROUND & AIMS

Mixed oil intravenous lipid emulsion (MO ILE) that contains 30% soybean oil (SO), 30% medium chain triglycerides, 25% olive oil and 15% fish oil can benefit hospitalized patients receiving parenteral nutrition (PN) but there are very few studies on its long-term use. Our goal was to evaluate the clinical outcomes of adults receiving home PN (HPN) with MO versus those receiving SO ILE over a 2-year period.

METHOD

This is a retrospective analysis of data collected prospectively from a cohort of patients recorded in the Canadian HPN Registry over a 2-year period. HPN patients from academic programs across Canada were entered in the Registry according to a validated protocol. For this study, demographic, nutritional, laboratory and clinical data were extracted from January 1st 2015, when MO lipid emulsion became available in Canada, to July 24th 2019. Clinical data for each patient included: number of hospitalizations, number of hospitalizations related to HPN and number of hospitalization days related to HPN, over a year; incidence of line sepsis per 1000 catheter days and mortality. Data are presented as median (1st, 3rd quartile) for continuous variables and frequency (percentage) for categorical variables. Comparisons between groups were performed using two sample t-test or Wilcoxon Rank Sum tests for continuous variables and Chi-square tests or Fisher's exact tests for categorical variables. Univariate and multiple linear regressions were also carried out. Statistical significance is set at a p-value <0.05.

RESULTS

A total of 120 patients were included (MO n = 68, SO n = 52). Significant differences at baseline between the two groups were a higher use of Hickman line (62.12% vs 42%, p = 0.038) and more western Canada based hospital care with MO (75% vs 42.31%, p = 0.0002). The MO group had significantly more hospitalizations (p = 0.001), more hospitalizations related to HPN (p = 0.012) and more hospitalization days related to HPN (p = 0.016) per patient per year compared to SO patients. There was no significant difference between groups for line sepsis per 1000 catheter days (MO: 0.05 (0.0, 1.0) vs SO: 0.0 (0.0, 0.22), p = 0.053) or mortality. All other variables, including biochemical variables, were similar between groups. In a multiple regression analysis, the following factors were significantly associated with a greater number of hospitalizations per patient per year: use of MO, high blood glucose from the last recorded value and having died by the end of the study period.

CONCLUSION

This 2-year prospective cohort study suggests an increased risk of hospitalization in HPN patients receiving MO lipid emulsion. The long-term effect of using MO lipid emulsion in HPN patients should be further evaluated using a large randomized controlled trial. THE STUDY WAS REGISTERED IN CLINICALTRIALS.GOV: (NCT02299466).

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.

Lipid Injectable Emulsions: 2006

Lipid injectable emulsions are an essential source of fatty acids, as well as a daily source of calories. They have been used in the clinical setting for almost 40 years, but despite this, there are no established official standards governing pharmaceutical quality. After 15 years of development, the United States Pharmacopeia (USP), which writes such standards for all FDA-approved pharmaceuticals, is poised to adopt an official monograph for lipid injectable emulsions that sets pharmaceutical requirements on all manufacturers placing limits on pH, free fatty acid concentrations and globule size (both mean droplet size and the population of large fat globules larger than 5 micrometers). Recent animal data has shown pathophysiologic changes in vital organs for lipids that fall outside the USP-proposed globule size limits. From a clinical perspective, newer lipid injectable emulsions show great promise in certain patient settings, most notably in the intensive care unit in both adults and infants. The clinical use of alternative oils, such as medium-chain triglycerides, fish oil and olive oil show benefits over conventional soybean oil formulations. In adults, for example, the administration of omega-fatty acids via soybean oil-based lipids produces a heightened inflammatory response via production of 2-series prostaglandins, whereas substitution of a portion of the lipid with omega-3 fatty acids via fish oil can favorably dampen the inflammatory response. In infants, for example, substitution of soybean oil with fish oil has recently been shown to reverse parenteral nutrition-associated liver disease. These advances should lead to safer infusion therapy in patients receiving lipid injectable emulsions.

Structured Triglyceride Emulsions in Parenteral Nutrition

Over the past 3 decades, various concepts for IV fat emulsions (IVFE) have been developed. A randomized, structured-lipid emulsion based on an old technology has recently become available. This structured-lipid emulsion is produced by mixing medium-chain triglycerides and long-chain triglycerides, then allowing hydrolysis to form free fatty acids, followed by random transesterification of the fatty acids into mixed triglyceride molecules. Studies in animals have shown an improvement in nitrogen balance with the use of these lipid emulsions. Only 8 human clinical studies with these products have been performed. The results of these human clinical studies have been less promising than the animal studies; however, an improvement in nitrogen balance and lipid metabolism exceeds results associated with infusion of long-chain triglycerides (LCT) or a physical mixture of long-chain triglycerides and medium-chain triglycerides (LCT-MCT). Structured-lipid emulsion seems to induce less elevation in serum liver function values compared with standard IVFEs. In addition, structured-lipid emulsions have no detrimental effect on the reticuloendothelial system. Further studies are necessary in order to recommend the use of structured-lipid emulsions. The clinical community hopes that chemically defined structured triglycerides will make it possible to determine the distribution of specific fatty acids on a specific position on the glycerol core and therefore obtain specific activity for a specific clinical situation.

Formulation of multifunctional oil-in-water nanosized emulsions for active and passive targeting of drugs to otherwise inaccessible internal organs of the human body

Oil-in-water (o/w) type nanosized emulsions (NE) have been widely investigated as vehicles/carrier for the formulation and delivery of drugs with a broad range of applications. A comprehensive summary is presented on how to formulate the multifunctional o/w NE for active and passive targeting of drugs to otherwise inaccessible internal organs of the human body. The NE is classified into three generations based on its development over the last couple of decades to make ultimately a better colloidal carrier for a target site within the internal and external organs/parts of the body, thus allowing site-specific drug delivery and/or enhanced drug absorption. The third generation NE has tremendous application for drug absorption enhancement and for 'ferrying' compounds across cell membranes in comparison to its first and second generation counterparts. Furthermore, the third generation NE provides an interesting opportunity for use as drug delivery vehicles for numerous therapeutics that can range in size from small molecules to macromolecules.

Nutrition support of the traumatically injured warfighter

Major trauma induces metabolic alterations that contribute to the systemic immune suppression in severely injured patients and increase the risk of infection and posttraumatic organ failure. Nutrition modulation of cellular processes has evolved into a high-priority therapy, backed by substantial scientific evidence. The appropriate selection, timing, and dose of nutrients required for metabolic resuscitation must be individualized and goal directed. Ideally, the nutritional interventions for warfighters will be developed strategically based on the extent of injuries and underlying deficiencies and will be designed to provide the nutrients necessary to balance hypermetabolic processes, heal wounds, and promote optimal recovery.

The hypertriglyceridemic clamp technique. Studies using long-chain and structured triglyceride emulsions in healthy subjects

In a randomized crossover study, plasma kinetics of 2 different types of fat emulsions were studied in 8 healthy volunteers by using a hypertriglyceridemic clamp technique. The method involves the stabilization of serum triglyceride (TG) concentration during 180 minutes at a predetermined level (4 mmol/L) by adjustment of TG infusion rate by repeated online measurements of serum TG concentration. The fat emulsions under study were a long-chain fatty acid triglyceride (LCT) emulsion (Intralipid 20%, Fresenius Kabi, Sweden) and a structured triglyceride (STG) emulsion (Structolipid 20%, Fresenius Kabi) where medium- and long-chain fatty acids have been interesterified within a TG molecule. The hypertriglyceridemic clamp was found to have acceptable reproducibility when tested in 3 healthy individuals on 2 different occasions, as similar steady-state TG levels were obtained by infusing similar amounts of fat. The average (+/-SEM) TG concentration during the 180-minute clamp was similar for STGs and LCTs (4.0 +/- 0.1 vs 3.9 +/- 0.1 mmol/L; not significant), but the amount of fat that had to be infused was significantly higher during STG than during LCT clamping (0.31 +/- 0.04 vs 0.21 +/- 0.02 g TG per minute; P < .05). Higher serum levels of free fatty acids (1.80 +/- 0.13 vs 0.96 +/- 0.09 mmol/L; P < .05), free glycerol (1.30 +/- 0.07 vs 0.76 +/- 0.08 mmol/L; P < .001), and beta-OH butyrate (1.61 +/- 0.44 vs 1.17 +/- 0.23 mmol/L; not significant) were obtained at the end of the clamp during infusion of STGs compared with LCTs. During infusion of STGs the medium-chain fatty acids octanoic (C:8) and decanoic acid (C:10) constituted approximately half of circulating fatty acids that correspond to the compositional ratio of the emulsion. Plasma lipoprotein lipase (LPL) concentration was higher during STG than during LCT clamping (6.06 +/- 0.62 vs 3.15 +/- 0.40 mU/mL; P < .05), and there was a positive correlation between the mean LPL concentration and the amount of infused TG during the steady-state period (r = 0.58; P < .05). In conclusion, the hypertriglyceridemic clamp method was found to give reproducible results and could be considered for comparison of metabolic clearance properties of different types of fat emulsions. The capacity of healthy subjects to eliminate STGs from blood was greater than for LCTs. An increased LPL activity induced by the higher TG infusion rate may have contributed to the increased metabolic clearance of STGs.

Early postoperative jejunostomy feeding with an immune modulating diet in patients undergoing resectional surgery for upper gastrointestinal cancer: A prospective, randomized, controlled, double-blind study

BACKGROUND

The provision of perioperative immune modulating enteral feeds after major surgery may result in reduced infective complications, but meta-analyses have not demonstrated a survival advantage. The aim of this study was to determine whether early postoperative immune modulating jejunostomy feeding results in reduced infective complications in patients undergoing resectional surgery for upper gastrointestinal cancer.

METHODS

A total of 120 patients undergoing resection for cancers of the pancreas, oesophagus and stomach were randomized in a double-blind manner to receive jejunostomy feeding with an immune modulating diet (Stresson-Group A) or an isonitrogenous, isocaloric feed (1250 Calories and 75 g protein/l--Nutrison High Protein-Group B) for 10-15 days. Feeding was commenced 4h postoperatively and continued for 20 h/day. The target volume (ml/h) was 25 on day 0, 50 on day 1, and 75 thereafter. Outcome measures included complications, hospital stay and mortality.

RESULTS

A total of 108 patients (54 in each group) were analysed. Feed delivery, although less than targeted, was similar in both groups. There were 6 (11%) deaths in each group. Median (IQR) postoperative hospital stay was 14.5 (12-23) days in Group A and 17.5 (13-23) days in Group B (P=0.48). A total of 24 (44%) patients in each group had infective complications (P=1.0). A total of 21 (39%) patients in Group A and 28 (52%) in Group B had non-infective complications (P=0.18). Jejunostomy-related complications occurred in 26 (48%) patients in Group A and 30 (56%) in Group B (P=0.3).

CONCLUSION

Early postoperative feeding with an immune modulating diet conferred no outcome advantage when compared with a standard feed.