Total parenteral nutrition-induced steatosis: reversal by parenteral lipid infusion

Safety Profile of Lipid Emulsion in Clinical Practice: A Pharmacovigilance Study Using the FDA Adverse Event Reporting System

INTRODUCTION

Lipid emulsion preparations, known for their clinical utility, are associated with various adverse events related to lipid metabolism. In this study, we analyzed the safety profile of lipid emulsions in clinical practice, using a real-world database.

METHODS

The US Food and Drug Administration Adverse Event Reporting System database was used to retrieve adverse events associated with lipid emulsion use. The risk of adverse events was evaluated based on the reported odds ratio and time-to-onset analysis.

RESULTS

A total of 4,430 relevant adverse event reports were identified. Hepatic dysfunction tended to occur in the early stages after administration, regardless of the lipid emulsion type. The incidence of hepatic dysfunction varies depending on the triglyceride content of the administered lipid emulsion. Infection tended to occur in the early stages of lipid emulsion administration; however, the incidence did not significantly differ depending on triglyceride content.

CONCLUSION

Our study revealed adverse lipid emulsion events, indicating the need for comprehensive safety management, particularly in the early stages, for clinical use. Particularly, patients receiving parenteral nutrition, irrespective of lipid emulsion administration, necessitate thorough monitoring of liver function and triglyceride levels and reassessment of infusion rates.

Lipid-Free PN is Associated with an Increased Risk of Hyperbilirubinemia in Surgical Critically Ill Patients with Admission Hepatic Disorder: A Retrospective Observational Study

Background

To evaluate the effect of different PN types on surgical critically ill trauma/acute care surgery patients with hepatic disorders at admission.

Methods

This is a retrospective study. The PN types included lipid-free, soybean oil/medium-chain triglyceride, olive oil-based, and fish oil-containing PNs. Patients admitted with liver injury or liver surgery, elevated serum AST/ALT level, and elevated serum total bilirubin level were included. The exclusion criteria are as follows: 1) age <18 years, 2) severe liver disease/cirrhosis, 3) received more than one type of PN and 4) serum total bilirubin >4.9 mg/dl at admission. Demographics, severity, comorbidities, blood stream infection, hyperbilirubinemia (total bilirubin > 6.0 mg/dl), and mortality were collected for analysis. We also performed analysis stratified by separated lipid doses (g/kg/day).

Results

A total of 156 patients were enrolled. There were no demographic differences among groups. The lipid-free group was associated with the highest mortality rate and incidence of hyperbilirubinemia. Compared to the lipid-free group, the olive oil-based group had the lowest risk of hyperbilirubinemia. After being stratified by separated lipid doses, the incidence of hyperbilirubinemia decreased when the lipid dosage increased. Regarding different types of lipids, patients who received more than the median dosage of lipids showed a significantly lower risk of hyperbilirubinemia, except in the fish oil-containing group.

Conclusion

Our result suggested that lipid-free PN is associated with an increased risk of hyperbilirubinemia in surgical critically ill patients with admission hepatic disorder. Further studies are warranted.

Polyphenolic Antioxidants in Lipid Emulsions: Partitioning Effects and Interfacial Phenomena

The autoxidation of lipids in complex systems such as emulsions or biological membranes, although known to occur readily and to be associated with important pathological events, is lacking in quantitative data in spite of the huge efforts that have been made in attempting to unravel the complex mechanisms of lipid oxidation and its inhibition by antioxidants. Lipids are present as oil-in-water emulsions in many foods and pharmaceutical formulations, and the prevalent role of the interfacial region is critical to understand the antioxidant behavior and to correctly interpret antioxidant efficiencies. The aim of this review is to summarize the current knowledge on the chemical fate of antioxidants before they react with peroxyl radicals. Many researchers highlighted the predominant role of interfaces, and although some attempts have been made to understand their role, in most instances, they were essentially qualitative and based on putative hypotheses. It is only recently that quantitative reports have been published. Indeed, knowledge on the effects of relevant experimental variables on the effective concentrations of antioxidants is necessary for a successful design of alternate, effective antioxidative solutions.

ESPGHAN Committee on Nutrition Position Paper. Intravenous Lipid Emulsions and Risk of Hepatotoxicity in Infants and Children: a Systematic Review and Meta-analysis

The aim of the present article was to perform a systematic review with meta-analysis of available scientific evidence regarding the role of different intravenous lipid emulsions (ILE) in the pathogenesis of cholestasis and parenteral nutrition-associated liver disease. A systematic review of the literature (up to March 2015) identified 23 randomized controlled trials (RCTs). Of these, 17 were performed in preterm infants or critically ill neonates with a short duration of intervention, 2 in older children with short-term use (following surgery or bone marrow transplantation), 1 in neonates with long-term use, and 3 in infants and children receiving long-term parenteral nutrition (PN). Meta-analysis showed no differences in the rate of cholestasis or bilirubin levels associated with short-term use of different ILEs. Because of high heterogeneity of the long-term studies no meta-analysis could be performed. Available studies found that the use of multicomponent fish oil (FO)-containing ILE compared with pure soya bean oil (SO), ILE-reduced liver enzymes, and bilirubin levels in noncholestatic children on long-term PN and one other RCT found that FO-based ILE-reversed cholestasis in a proportion of patients. The ESPGHAN Committee on Nutrition concludes that there is no evidence of a difference in rates of cholestasis or bilirubin levels between different ILE for short-term use in neonates. The use of multicomponent FO-containing ILE may contribute to a decrease in total bilirubin levels in children with IF on prolonged PN. Well-designed RCTs are, however, lacking and long-term effects have not been determined.

Omega-3-enriched lipid emulsion for liver salvage in parenteral nutrition-induced cholestasis in the adult patient

The intrahepatic cholestasis attributed to parenteral nutrition (PN) in the adult patient is relatively rare and usually occurs in patients receiving long-term PN. This article reports the first case of an adult patient with cholestatic PN-associated liver disease without sepsis who received almost all her nutrition requirements through PN. Administration of an ω-3-enriched lipid emulsion added to the PN regimen reversed cholestasis and demonstrated histologic improvement on serial liver biopsy. The patient had failed to respond to other modalities of treatment for this condition and was deeply jaundiced. Liver biochemistry profiles returned to baseline, and follow-up liver biopsy showed that cholestasis had resolved and that the only residual changes were mild portal inflammation with no histochemical or ultrastructural progression. The PN regimen for the patient was restored to provide total estimated energy requirements and remains the principle source of the patient's nutrition to date.

Lipid emulsions - Guidelines on Parenteral Nutrition, Chapter 6

The infusion of lipid emulsions allows a high energy supply, facilitates the prevention of high glucose infusion rates and is indispensable for the supply with essential fatty acids. The administration of lipid emulsions is recommended within ≤7 days after starting PN (parenteral nutrition) to avoid deficiency of essential fatty acids. Low-fat PN with a high glucose intake increases the risk of hyperglycaemia. In parenterally fed patients with a tendency to hyperglycaemia, an increase in the lipid-glucose ratio should be considered. In critically ill patients the glucose infusion should not exceed 50% of energy intake. The use of lipid emulsions with a low phospholipid/triglyceride ratio is recommended and should be provided with the usual PN to prevent depletion of essential fatty acids, lower the risk of hyperglycaemia, and prevent hepatic steatosis. Biologically active vitamin E (α-tocopherol) should continuously be administered along with lipid emulsions to reduce lipid peroxidation. Parenteral lipids should provide about 25–40% of the parenteral non-protein energy supply. In certain situations (i.e. critically ill, respiratory insufficiency) a lipid intake of up to 50 or 60% of non-protein energy may be reasonable. The recommended daily dose for parenteral lipids in adults is 0.7–1.3 g triglycerides/kg body weight. Serum triglyceride concentrations should be monitored regularly with dosage reduction at levels >400 mg/dl (>4.6 mmol/l) and interruption of lipid infusion at levels >1000 mg/dl (>11.4 mmol/l). There is little evidence at this time that the choice of different available lipid emulsions affects clinical endpoints.

Cholestasis induced by total parenteral nutrition

Parenteral nutrition is a life-saving treatment for patients who have acute and chronic intestinal failure. Severe cholestasis induced by total parental nutrition (TPN-IC) is characterized by bile duct regeneration, portal inflammation, and fibrosis. Its progression could be very rapid, and in some patients liver cirrhosis may develop in few months. This article describes the definition, incidence, hepatic changes, histopathologic findings, risk factors, pathogenesis, and clinical implications of TPN-IC. The goal is to improve hospital and home management, quality of life, and prognosis of patients requiring parenteral nutrition.

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.

Specific topics and complications of parenteral nutrition

BACKGROUND/AIMS

Total parenteral nutrition (TPN) has proven a tremendous advance in all disciplines in medicine but itself introduces a spectrum of possible complications related to both the parenteral nutritional solution as well as the technique of intravenous delivery. Our aim is to review the specific complications of TPN.

MATERIALS AND METHODS

This article presents a critical literature review of relevant topics in TPN-related complications-metabolic, infections, and nutrition related.

RESULTS

Special emphasis focuses on complications of TPN arising from thrombosis or infectious sequelae related to the central venous catheterization and metabolic complications involving the kidneys, bones, liver, and biliary tract.

CONCLUSIONS

Awareness and surveillance of TPN-related complications can prevent, potentially, some of these complications related to parenteral nutritional support.

Total parenteral nutrition-related gastroenterological complications

Total parenteral nutrition is a life saving therapy for patients with chronic gastrointestinal failure, being an effective method for supplying energy and nutrients when oral or enteral feeding is impossible or contraindicated. Clinical epidemiological data indicate that total parenteral nutrition may be associated with a variety of problems. Herein we reviewed data on the gastroenterological tract regarding: (i) total parenteral nutrition-related hepatobiliary complications; and (ii) total parenteral nutrition-related intestinal complications. In the first group, complications may vary from mildly elevated liver enzyme values to steatosis, steatohepatitis, cholestasis, fibrosis and cirrhosis. In particular, total parenteral nutrition is considered to be an absolute risk factor for the development of biliary sludge and gallstones and is often associated with hepatic steatosis and intrahepatic cholestasis. In general, the incidence of total parenteral nutrition-related hepatobiliary complications has been reported to be very high, ranging from 20 to 75% in adults. All these hepatobiliary complications are more likely to occur after long-term total parenteral nutrition, but they seem to be less frequent, and/or less severe in patients who are also receiving oral feeding. In addition, end-stage liver disease has been described in approximately 15-20% of patients receiving prolonged total parenteral nutrition. Total parenteral nutrition-related intestinal complications have not yet been adequately defined and described. Epidemiological studies intended to define the incidence of these complications, are still ongoing. Recent papers confirm that in both animals and humans, total parenteral nutrition-related intestinal complications are induced by the lack of enteral stimulation and are characterised by changes in the structure and function of the gut. Preventive suggestions and therapies for both these gastroenterological complications are reviewed and reported in the present review.

Treatment of intestinal failure: home parenteral nutrition

Intestinal failure can result from surgical resection, obstruction, dysmotility, congenital deficiencies or disease-associated loss of absorption. Before the development of intravenous feeding in the late 1960s, the condition was fatal, but by the 1990s approximately 40,000 patients were being successfully managed on long-term home parenteral nutrition (HPN) annually in the US. Survival on HPN depends on the nature of the underlying medical condition: over 80% of Crohn's disease patients survive for 5 years, but only 20% of cancer patients survive for 1 year. Although a patient's nutritional status is easy to maintain, there are serious long-term complications that arise from bypassing the gut and infusing nutrients directly into the systemic circulation. Catheter sepsis occurs about once per year (range 0-12 times). Abnormalities in liver function tests are common, but end-stage liver disease is rare. Central venous thrombosis develops in nearly all patients after 5 years. Although approximately 80% of patients on HPN are completely rehabilitated at home, their quality of life is impaired by the perpetual dependence on nocturnal intravenous infusions (every 8-12 h). In conclusion, HPN has allowed patients with previously fatal intestinal failure to survive and lead relatively normal lives at home, but their quality of life remains impaired by the dependence on intravenous infusions and complications that progress with time.

Parenteral nutrition-associated liver disease and the role for isolated intestine and intestine/liver transplantation

Parenteral nutrition-associated liver disease (PNALD) is the most devastating complication of long-term parenteral nutrition therapy. Because its progression is typically insidious and its long-term consequences are generally underappreciated, PNALD is often recognized too late, when liver injury is irreversible. When end-stage liver disease (ESLD) develops in these patients, most potential interventions are futile and transplantation of both an intestine and a liver becomes the only viable option, despite the relatively poor outcomes associated with this combined procedure. Although likely multifactorial in origin, the etiology of PNALD is poorly understood. Early clinical intervention with a combination of nutritional, medical, hormonal, and surgical therapies can be effective in preventing liver disease progression. If these interventions fail, intestinal transplantation should be performed expeditiously before development of ESLD mandates simultaneous inclusion of a liver graft as well.

Soybean Oil Fat Emulsion Prevents Cytochrome P450 mRNA Down-Regulation Induced by Fat-Free Overdose Total Parenteral Nutrition in Infant Rats

Changes in the mRNA expression of hepatic cytochrome P450 (CYP) isoenzymes associated with overdose of fat-free or fat-containing total parenteral nutrition (TPN) were investigated in infant rats. Three-week-old male Sprague-Dawley rats were divided into three groups: group 1 received an oral diet, group 2 received TPN without fat, and group 3 received TPN with 20% of calories from fat (soybean oil emulsion). After TPN administration for 4 d, serum aspartate aminotransferase (AST) levels in group 2 were significantly increased (p<0.01) compared with the other groups. The mRNA expression of hepatic CYP isoenzymes in group 2 decreased to 0.76 to 31% of that in group 1 (p<0.01), but that in group 3 was maintained at 32 to 84% of that in group 1. These results indicate the importance of including fat in TPN regimens to prevent not only hepatic dysfunction but also mRNA down-regulation of liver CYP isoenzymes.

Postoperative jaundice and total parenteral nutrition-associated hepatic dysfunction

Postoperative jaundice and TPN-induced hepatic abnormalities represent clinical situations that stem from multiple and frequently overlapping insults to the liver. The pattern of LFT abnormalities and appropriate imaging studies provide clues to the diagnosis. Greater insight into the molecular basis of cholestasis has shed light on the possible common pathways for the hepatic derangements that are seen in diverse situations. TPN-related hepatic dysfunction most likely involves a combination of nutritional deficiencies, hormonal imbalances, excessive calories, and possibly bacterial overgrowth in the small bowel. Growing clinical evidence points to a high incidence of severe liver disease in chronic TPN-dependent patients. Careful monitoring of patients is warranted in these circumstances and combined transplantation of the liver and small bowel may be the only possibility for long-term survival for such patients with progressive liver disease.

Parenteral nutrition-associated liver complications in children

Parenteral nutrition is a life-saving therapy for patients with intestinal failure. It may be associated with transient elevations of liver enzyme concentrations, which return to normal after parenteral nutrition is discontinued. Prolonged parenteral nutrition is associated with complications affecting the hepatobiliary system, such as cholelithiasis, cholestasis, and steatosis. The most common of these is parenteral nutrition-associated cholestasis (PNAC), which may occur in children and may progress to liver failure. The pathophysiology of PNAC is poorly understood, and the etiology is multifactorial. Risk factors include prematurity, long duration of parenteral nutrition, sepsis, lack of bowel motility, and short bowel syndrome. Possible etiologies include excessive caloric administration, parenteral nutrition components, and nutritional deficiencies. Several measures can be undertaken to prevent PNAC, such as avoiding overfeeding, providing a balanced source of energy, weaning parenteral nutrition, starting enteral feeding, and avoiding sepsis.

Complications of long-term home total parenteral nutrition: their identification, prevention and treatment

The purpose of this review is to describe the most common complications of home total parenteral nutrition, their identification, treatment and prevention. Data sources were manuscripts and abstracts published in the English literature since 1968. Studies were selected for summarization in this review on the basis of clinical relevance to the practicing clinician. Home total parenteral nutrition is a relatively safe, life-saving method for nutrient delivery in patients with compromised gastrointestinal function. However, numerous complications, with associated morbidity and mortality, involving the delivery system and the gastrointestinal, renal, and skeletal systems may develop. Catheter-related complications are often preventable and treatable when they occur, although renal and bone abnormalities have elusive etiologies.

Hepatic dysfunction as the presenting feature of acute lymphoblastic leukemia

PURPOSE

Hepatic dysfunction is a rare presentation of leukemia in children. Because most chemotherapy agents are metabolized by the liver, this complication may have major adverse consequences and effective treatment could be compromised.

PATIENTS AND METHODS

The MEDLINE database and current management guidelines from the United States Pediatric Cooperative Cancer Groups were reviewed and analyzed. Data from two institutional cases are described.

RESULTS

Although previous literature is not informative, our experience suggests that children with leukemia and moderate hepatic dysfunction may tolerate aggressive chemotherapy.

CONCLUSION

Current protocol guidelines for dose modification for liver disease may be overly stringent and modification may be beneficial.

Role of lipid emulsions in cholestasis associated with long-term parenteral nutrition in children

BACKGROUND

In children who depend on long-term parenteral nutrition (PN), liver disease is a major complication that may lead to end-stage liver failure requiring liver transplantation.

METHODS

This retrospective study investigated the influence of lipid emulsions on cholestasis onset in children receiving long-term total parenteral nutrition (TPN) with lipids. Ten children who presented with a total of 23 episodes of cholestasis, associated in 13 cases with thrombocytopenia, were studied.

RESULTS

Changes in the lipid delivery preceded these complications in more than half the cases. The temporary decrease in lipid administration led to normalization of bilirubin in 17 episodes.

CONCLUSIONS

These data suggest that lipid supply is one of the risk factors for PN-associated cholestasis. The link between cholestasis and the reticuloendothelial system overload needs to be better understood. Prevention of cholestasis might include the decrease in the lipid load. When cholestasis occurs, lipid supply should be temporarily stopped, especially in the case of associated thrombocytopenia.

Home parenteral nutrition. 25 years later

After 25 years, there is enough clinical outcome experience to determine appropriate use of home parenteral nutrition in different disease states and age groups. Information regarding how to avoid complications and how patients and families can find necessary psychosocial support is provided in this article. Currently, small bowel transplantation is not a safer choice, unless there is severe liver disease caused by home parenteral nutrition or lack of central intervenous access.

Liver dysfunction and parenteral nutritional therapies

Hepatobiliary dysfunction associated with the use of total parenteral nutrition is a commonly recognized phenomenon occurring in up to 90% of patients on long-term therapy. Reasons for these abnormalities, both supported by research as well as theoretical possibilities are explored. Practical guidelines considered useful in documenting, preventing and treating serious hepatic consequences of total parenteral nutrition are discussed. The role of combined liver and small bowel transplantation as treatment for select patients is also reviewed.

Effect of L-glutamine supplementation on impaired glucose regulation during intravenous lipid administration

In contrast to L-glutamine, lipid emulsions are routinely administered to patients receiving nutritional support. The provision of fat during intravenous feeding is essential, but the potentially toxic byproducts of fatty acid oxidation may have adverse metabolic consequences. In the present study, we have examined the effect of L-glutamine, an inhibitor of fatty acid oxidation, on the development of defective blood glucose regulation caused by a 48-hour infusion of 10% intralipid in rats. Male Sprague-Dawley rats (200-290 g) were anesthetized with sodium pentobarbital, the right femoral vein cannulated, and baseline blood samples were taken. Each rat was placed in a metabolic cage with access to water, in the presence or absence of rodent chow. Two hours after waking, the rats were infused with 10% intralipid with either saline (control), 2% L-glutamine, or 2% L-alanine. After 48 hours, all animals were sacrificed and blood samples were again obtained. The mean +/- SEM plasma glucose levels before and after lipid infusion at the rate of 1 mL/hr in control rats fed ad libitum, were 125 +/- 13 and 170 +/- 5 mg/dL (p < 0.01, n = 7). Similarly, plasma free fatty acids (FFA) in these animals rose from 0.74 +/- 0.11 to 1.34 +/- 0.32 mmol/L (p < 0.05). Plasma insulin levels also increased from 337 +/- 44 to 1278 +/- 88 pg/mL (p < 0.01). Reduction of intralipid dose infusion did not prevent insulin resistance characterized by hyperglycemia and hyperinsulinemia. However, addition of L-glutamine to the high-dose lipid infusion with chow feeding prevented changes in plasma glucose, insulin levels, and FFA but not triglyceride levels. Also, glutamine but not alanine supplementation in intralipid infused rats without chow feeding prevented changes in plasma glucose, insulin, and malondialdehyde levels. In conclusion, these data show that glutamine supplementation during intravenous lipid administration in rats prevents the development of impaired glucose regulation associated with hyperlipidemia.

Liver and biliary tract changes and injury associated with total parenteral nutrition: pathogenesis and prevention

Total parenteral nutrition (TPN), now widely used, is successful in preventing and reversing malnutrition in individuals with various diseases and conditions. However, hepatic and biliary complications of TPN are encountered in both adult and pediatric patients. Certain complications, such as sepsis and TPN-associated cholestasis, occur more frequently in very young infants. Continuing problems commonly seen in adults are steatosis and steatonecrosis. Reasons for the development of these complications are multifactorial. Etiologies of hepatic complications, especially the role of deficiency/excess of nutrients in the pathogenesis of hepatobiliary disorders, are summarized. Complications caused by the duration of TPN are discussed with emphasis on prevention and management. Evidence now suggests that prompt enteral feeding, even in minimal amounts, may prevent many of the metabolic complications associated with TPN. TPN should be used only in amounts meeting needs and for a duration essential to survival.

Metabolic effect of parenteral nutrition in dogs with obstructive jaundice

OBJECTIVE

To assess the effect of total parenteral nutrition (TPN) on macronutrient metabolism in obstructive jaundice.

METHODS

Forty adult mongrel dogs were equally divided into four groups: group I (PO-control) received sham ligation of common bile duct (CBDL) and was fed dog chow and water ad libitum; group II (PO-CBDL) underwent CBDL and was fed dog chow; group III (TPN-control) received sham CBDL and TPN; and group IV (TPN-CBDL) underwent CBDL and received TPN. Blood chemistries, plasma amino acids and liver histologies were studied before (Day 1) and at the end (Day 14) of the experiment.

RESULTS

A significant elevation of bilirubin and alkaline phosphatase was observed in dogs with CBDL. Blood glucose was not changed significantly in any group. Significant increases in triglyceride and cholesterol were present in CBDL dogs. Significant differences in the concentrations of a few plasma amino acids, including an elevation of phenylalanine, were found in TPN dogs. A significant increase in aromatic amino acids (AAA) and a noticeable depression of the molar ratio of branched-chain amino acids (BCAA) to AAA was present in TPN-CBDL dogs, as was a significant increase in blood ammonia.

CONCLUSION

In the presence of obstructive jaundice, TPN does not significantly affect carbohydrate or lipid metabolism. However, a derangement in protein metabolism with the standard TPN solution in current use suggests that either a modification of amino acid composition or an increase in total energy to protein energy ratio in TPN solution may be necessary to obviate such a consequence.

Small intestinal mucosa changes, including epithelial cell proliferative activity, of children receiving total parenteral nutrition (TPN)

We examined the small intestinal histology disaccharidase activities as well as the incorporation of [3H]thymidine into DNA of biopsies maintained in organ culture from seven children (ages 9 months to 5 years) receiving total parenteral nutrition (TPN). Three children suffered from inflammatory bowel disease and received TPN for one month (short term). Four required long-term TPN (> 9 months) for short-bowel syndrome. DNA was extracted from the samples following serial precipitation with perchloric acid. Results were compared to those from 22 age-matched children investigated for abdominal pain or chronic diarrhea. Short-term TPN resulted in slightly lower lactase, sucrase, and palatinase activities that were not statistically different from controls. Long-term TPN resulted in focal mild villus atrophy and a decrease in disaccharidase activity in two patients. Biopsies from long-term TPN patients incorporated less thymidine compared to those of controls (P < 0.001) when data was expressed per total biopsy (3.6 +/- 1.1 vs. 8.4 +/- 1.1 fmol) or per milligram of tissue (1.0 +/- 0.12 vs 2.7 +/- 0.7 fmol). The above data are in general agreement with the hypoplastic effect of TPN in animals. However, in children, much longer periods of TPN are required to realize the changes.

Hepatobiliary complications of total parenteral nutrition

The relationships between various hepatobiliary disorders and the administration of total parenteral nutrition (TPN) were reviewed and, in particular, the role of TPN in their pathogenesis was critically evaluated. Several clinical and pathological entities including steatosis, steatohepatitis, cholestasis, and cholelithiasis have been commonly linked to TPN, and instances of chronic decompensated liver disease have been reported. However, it is concluded that it is often difficult to extricate the effects of TPN on hepatobiliary function from many other hepatotoxic factors that may be operative in these patients. Thus, whereas considerable evidence exists to support a role fro carbohydrate or calorie excess in TPN solutions in the pathogenesis of steatosis, a loss of enteric stimulation and not TPN per se may be the primary factor in the development of cholestasis, biliary sludge, and gallstones. The apparent predilection of infants to TPN-related cholestasis may be based on the relative immaturity of the neonatal biliary excretory system.

Intravenous fat emulsions in clinical practice

The use of intravenous fat emulsions has become an integral part of the provision of parenteral nutrition. In the past, this was achieved by the administration of lipids separately from the dextrose-amino acid base solution. More recently, lipids have been admixed along with the dextrose-amino acid formula as a total nutrient admixture (TNA). This article discusses the advantages and disadvantages of TNAs, the factors that affect the stability of emulsions, the potential for microbial growth in TNAs, and guidelines for the compounding of TNAs.

Insulinotropic potency of lauric acid: a metabolic rationale for medium chain fatty acids (MCF) in TPN formulation

The need for a better lipid system to satisfy the fuel requirements of patients while avoiding the adverse effects of current systems has led to suggestions that medium chain fatty acids (MCFs) be incorporated into TPN-lipid emulsions. Since clinical situations requiring TPN are associated with metabolic processes mediated by insulin, in the present study we have therefore examined the effects of a variety of medium chain fatty acids on insulin release. Using an isolated perifused mouse islet model, various doses of medium chain fatty acids and the essential fatty acid, linoleic acid, were tested and compared. The possibility of an additive effect of an insulinotropic MCF and linoleate when both are provided together was also examined. Effluent perifusate samples collected on ice during these experiments were assayed for insulin by radioimmunoassay. It was found that the ability of 5 mM of a given MCF to stimulate insulin secretion was dependent upon its chain length. Thus, while adipic acid (C6) had no effect, Caprylic acid (C8) had a minimal effect that was not statistically significant, but capric acid (C10) and lauric acid had very potent effects that were of the same magnitude to the effect of linoleate on insulin secretion. When insulin output was assessed as the mean integrated area under the curve during a 20-min perifusion, 5 mM lauric acid enhanced insulin secretion from a basal 7351 +/- 666 pg to 15,756 +/- 1680 pg (P less than 0.01, n = 5). In the same experiments, 5 mM linoleic acid stimulated insulin release to 11,260 +/- 867 pg (P less than 0.05). When C12 and linoleate were added together, each at a submaximally effective concentration of 2.5 mM, insulin output was 12,712 +/- 1011 pg (P less than 0.05, n = 5), which was not statistically different from the values obtained when the islets were perifused with 5 mM of each fatty acid alone.(ABSTRACT TRUNCATED AT 250 WORDS)