Liver phospholipidosis induced by parenteral nutrition: histologic, histochemical, and ultrastructural investigations

Fatty foci within the heart diagnosed with ECG-gated multi-slice computed tomography: frequency and morphology

BACKGROUND

The purpose of our study was to analyze the frequency of focal fatty replacement (FR) of the heart, as well as the distribution and detailed morphology of FR in a large group of patients referred to multi-slice computed tomography with ECG-gating examinations (ECG-MSCT) for various clinical reasons.

MATERIAL AND METHODS

The ECG-MSCT examinations of 1830 consecutive patients were analyzed. The examinations were performed using 8-row (1015 patients) and 64-row (815 patients) MSCT, in pre- and post-contrast scanning. We analyzed the morphology of FR, the dimensions and densities of changes, as well as the morphology and localization of FR with regard to clinical diagnosis.

RESULTS

204 subjects (11.1%) had FR within the heart (113 men; 91 women; mean age 57.8 years); 66% of fatty foci were seen only in the native scanning. The distribution of the fat was: right ventricle (RV) 31.9%, left ventricle (LV) 21.5%, biventricular 39.7%, interventricular or atrial septum 5.9%, and atria 1%. In the RV, fat was localized mainly in the papillary muscles, while in the LV fat was mainly subendocardial (p<0.001). The morphology of the fat was: linear 61.6%, oval 14.8%, punctuate 10.6%, irregular 10.2%, and bilobular 2.8%. Fat was primarily located subendocardially in the LV in patients after myocardial infarction. In patients with suspected coronary artery disease, it was mainly observed subpericardially in the RV and in papillary muscles (p<0.001).

CONCLUSIONS

The incidental frequency of FR within the heart in patients diagnosed with the ECG-MSCT examinations is about 11%. Pre-contrast scanning is the most valuable for FR assessment.

Histopathologic manifestations of drug-induced hepatotoxicity

Drug-induced hepatotoxicity is underrecognized but increasingly identified as causing acute and chronic liver disease. Several prescription drugs, over-the-counter medications, dietary and/or supplementary agents, and herbal products are hepatotoxic. Drug-induced liver injury mimics other primary acute and chronic liver diseases and it should be considered in patients with hepatobiliary disease. Certain drugs result in specific histopathologic patterns of liver injury, which may help in sorting out the responsible drug. The diagnosis of drug-induced hepatotoxicity is challenging. It involves excluding other possible causes, careful medication history, the latent period between drug exposure and symptom onset and/or abnormal liver tests, and histopathologic findings.

Pathogenesis and treatment of parenteral nutrition-associated liver disease

BACKGROUND

Parenteral nutrition-associated liver disease (PNALD) has been common in patients who require long-term parenteral nutrition. PNALD develops in 40%-60% of infants on long-term parenteral nutrition compared with 15%-40% of adults on home parenteral nutrition for intestinal failure. The pathogenesis of PNALD is multifactorial and remains unclear. There is no specific treatment. Management strategies for its prevention and treatment depend on an understanding of many risk factors. This review aims to provide an update on the pathogenesis and treatment of this disease.

DATA SOURCES

A literature search was performed on the MEDLINE and Web of Science databases for articles published up to October 2011, using the keywords: parenteral nutrition associated liver disease, intestinal failure associated liver disease, lipid emulsions and fish oil. The available data reported in the relevant literatures were analyzed.

RESULTS

The literature search provided a huge amount of evidence about the pathogenesis and management strategies on PNALD. Currently, lack of enteral feeding, extended duration of parenteral nutrition, recurrent sepsis, and nutrient deficiency or excess may play important roles in the pathogenesis of PNALD. Recent studies found that phytosterols, present as contaminants in soy-based lipid emulsions, are also an important factor in the pathogenesis. Moreover, the treatment of PNALD is discussed.

CONCLUSIONS

The use of lipid emulsions, phytosterols in particular, is associated with PNALD. Management strategies for the prevention and treatment of PNALD include consideration of early enteral feeding, the use of specialized lipid emulsions such as fish oil emulsions, and isolated small bowel or combined liver and small bowel transplantation. A greater understanding of the pathogenesis of PNALD has led to promising interventions to prevent and treat this condition. Future work should aim to better understand the mechanisms of PNALD and the long-term outcomes of its treatment.

Lipomatous hypertrophy of the interatrial septum in ECG-gated multislice computed tomography of the heart

BACKGROUND

Lipomatous hypertrophy of the interatrial septum (LHIS) is a benign disorder characterized by fat accumulation in the interatrial septum (IAS). The purpose of the study was to analyze the incidental detection of LHIS in patients with various clinical conditions, referred to ECG-gated multislice computed tomography (ECG-MSCT) examinations of the heart.

MATERIAL/METHODS

The ECG-MSCT examinations of 5786 patients (2839 women; 2947 men), were analyzed. The examinations were performed using 8-row (1015 patients) and 64-row (4771 patients) MSCT, in pre- and postcontrast scanning. We analyzed the shape of the IAS, density and maximal thickness of IAS, the thickness of the epicardial adipose tissue, and the degree of contact of IAS with the ascending aorta and superior vena cava. We also determined body mass index (BMI) in patients with LHIS.

RESULTS

LHIS was detected in 56 (0.96%) patients, with an average age of 61.5±9.8 years. The mean BMI in the analyzed group was 30.1±4.86. During the end-diastolic phase the thickness of IAS was significantly higher (p<0.0001), and on average equaled 18.3 mm. The mean optical density of the IAS was conspicuously higher (p<0.0001) in post-contrast phase than in pre-contrast phase. The thickness of the epicardial adipose tissue in the region of the left atrioventricular groove was on average 15 mm. In all cases the dumbbell shape of IAS was observed.

CONCLUSIONS

The incidental frequency of LHIS occurrence in patients diagnosed with the ECG-MSCT examinations is about 1%. In most subjects it is linked with a higher BMI and increased thickness of the epicardial adipose tissue.

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.

Potential usefulness of olive oil-based lipid emulsions in selected situations of home parenteral nutrition-associated liver disease

Long-term (i.e. home) parenteral nutrition has been advocated to be responsible for several metabolic complications among which hepatic disorders have long been the most relevant in view of patients' prognosis. The increased knowledge of the pathophysiologic factors associated to parenteral nutrition-related liver disease as well as the regular improvement of the components and the techniques used for parenteral nutrition leaded progressively to a better prevention of these side effects. This case report focuses on the potential interest of olive oil-based lipid emulsions in home parenteral nutrition patients, in selected situations of home parenteral nutrition-associated metabolic liver disease.

Other disease associations with non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is usually seen in middle-aged women with obesity, non-insulin-dependent diabetes mellitus and/or hyperlipidaemia. NAFLD has also been associated with other conditions. Surgical procedures to treat obesity such as jejunoileal bypass and gastroplasty as well as massive small bowel resection have been associated with NAFLD. Mechanisms such as rapid weight loss, certain nutritional deficiencies and bacterial overgrowth have been proposed. Other nutritional conditions such as extreme malnutrition and total parenteral nutrition can also cause NASH. This can be due to abnormal glucose and fat metabolism, deficiencies like carnitine, essential fatty acid and choline or, in the case of parenteral nutrition, excess of calories, glucose or lipids. Several drugs have also been implicated as well as some inborn errors of metabolism and, more rarely, other diseases.

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.

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.

Effect of intravenous lipid emulsions on hepatic cholesterol metabolism

BACKGROUND

Total parenteral nutrition offers the chance of survival to children who have had extensive gut resections or gut failure. However, in infants it is often associated with serious complications including cholestatic liver disease. The causes of these complications remain unclear, although it has been suggested that the lipid emulsions used in total parenteral nutrition may be responsible.

METHODS

An in vitro system was developed to study the effect of lipid emulsions on hepatic cholesterol metabolism using cultured hepatocytes.

RESULTS

Incubations of Hep G2 cells with medium containing Intralipid (Pharmacia and Upjohn, Milton Keynes, UK) demonstrated that the fat emulsion mediated a powerful dose-dependent but reversible inhibition of cholesterol uptake. In addition Intralipid was shown to stimulate the efflux of cholesterol from Hep G2 cells. The component or components of the Intralipid responsible for these effects and the mechanism by which they act remain to be established.

CONCLUSIONS

Intravenous lipid emulsions may interfere with hepatic cholesterol metabolism in vivo. This may have implications for the development of total parenteral nutrition-associated cholestasis in neonates.

Prevalence of liver disease and contributing factors in patients receiving home parenteral nutrition for permanent intestinal failure

BACKGROUND

Liver cholestasis can be a life-threatening complication during home parenteral nutrition and may lead to combined liver-intestinal transplantation.

OBJECTIVE

To assess the prevalence of home parenteral nutrition-related liver disease and its contributing factors in patients with permanent intestinal failure.

DESIGN

Prospective cohort study.

SETTING

Two approved home parenteral nutrition centers.

PATIENTS

90 patients with permanent intestinal failure who were receiving home parenteral nutrition were enrolled from 1985 to 1996.

INTERVENTION

Clinical, biological, endoscopic, and ultrasonographic follow-up. Histologic examination of the liver was done in 57 patients (112 liver biopsies).

MEASUREMENTS

The Kaplan-Meier method was used to determine the actuarial occurrence of chronic cholestasis and complicated home parenteral nutrition-related liver disease (bilirubin level > or =60 micromol/L [3.5 mg/dL], factor V level < or =50%, portal hypertension, encephalopathy, ascites, gastrointestinal bleeding, or histologically proven extensive fibrosis or cirrhosis). Contributing factors were assessed by using univariate and multivariate (Cox model) analysis.

RESULTS

58 patients (65%) developed chronic cholestasis after a median of 6 months (range, 3 to 132 months), and 37 (41.5%) developed complicated home parenteral nutrition-related liver disease after a median of 17 months (range, 2 to 155 months). Of these patients, 17 showed extensive fibrosis after 26 months (range, 2 to 148 months) and 5 had cirrhosis after 37 months (range, 26 to 77 months). The prevalence of complicated home parenteral nutrition-related liver disease was 26%+/-9% at 2 years and 50%+/-13% at 6 years. Six patients died of liver disease (22% of all deaths). In multivariate analysis, chronic cholestasis was significantly associated with a parenteral nutrition-independent risk for liver disease, a bowel remnant shorter than 50 cm in length, and a parenteral lipid intake of 1 g/kg of body weight per day or more (omega-6-rich long-chain triglycerides), whereas complicated home parenteral nutrition-related liver disease was significantly associated with chronic cholestasis and lipid parenteral intake of 1 g/kg per day or more.

CONCLUSION

The prevalence of complicated home parenteral nutrition-related liver disease increased with longer duration of parenteral nutrition. This condition was one of the main causes of death in patients with permanent intestinal failure. Parenteral intake of omega-6-rich long-chain triglycerides lipid emulsion consisting of less than 1 g/kg per day is recommended in these patients.

Structure and metabolic fate of triacylglycerol- and phospholipid-rich particles of commercial parenteral fat emulsions

The lipid emulsions used in parenteral nutrition are constituted of particles rich in triacylglycerols (TAG) called artificial chylomicrons (200-500 nm in diameter; monolayer of phospholipids [PL] enveloping a TAG core) and PL-rich particles called liposomes (diameter inferior to 80 nm; bilayer of PL around an aqueous phase), which represent the excess emulsifier. Introduced into the circulation, the two populations of particles come into contact with circulating lipoproteins and cell membranes and experience the same overall fate: exchanges and transfers of lipids and apolipoproteins, enzymatic hydrolysis of TAG and PL, and internalization by different tissues. The relative importance of these different metabolic processes varies depending on the type of particle. The artificial chylomicrons undergo a hydrolysis of their TAG by lipoprotein lipase, with a release of fatty acids and formation of smaller particles of remnants, which are rapidly removed by the liver. In delivering fatty acids to the tissue, artificial chylomicrons fulfill an energy transport function similar to the natural chylomicrons. The liposomes hold little energy interest, and they also have deleterious effects when infused in excess. They inhibit the lipolysis of artificial chylomicrons and, by actively capturing endogenous cholesterol, they stimulate tissue cholesterogenesis and accumulate in the blood as lipoprotein-X, a long-lived abnormal lipoprotein. To limit as much as possible the metabolic perturbations due to the intravenous administration of exogenous PL, the emulsion has to be infused at a low rate, and should contain the minimal amount of excess PL.

Sea-blue histiocyte syndrome in bone marrow secondary to total parenteral nutrition

Clinical and hematological abnormalities can occur in patients receiving intravenous fat emulsions as part of a long-term parenteral nutrition; they consist of hepatosplenomegaly and peripheral blood cytopenia(s). These abnormalities lead to bone marrow examination which revealed numerous macrophages laden with blue staining pigment granules and separate lipid vacuoles, presenting the typical histochemical characteristics of sea-blue histiocytes. Thus, long-term parenteral nutrition including fat-emulsion sources may represent a further condition in addition to the wide variety of disorders which can be associated with sea-blue histiocytosis. Moreover, in view of its clinical and morphological presentation, this storage pathological state could be compared with the so-called sea-blue histiocyte syndrome described by Silverstein and colleagues.

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.

Home parenteral lipids in AIDS: a three-month study

Parenteral nutrition is a part of the nutritional support regimen of patients with AIDS-associated wasting syndrome and gastrointestinal dysfunction. The cholesterol (CHOL) level in human immunodeficiency virus (HIV) membrane is very high, and recent lipid formulations with high phospholipid (PL) content have demonstrated the ability to trap CHOL from endogenous sources, modifying the composition of cell membranes. We administered lipid-based home parenteral nutrition for 3 mo to malnourished AIDS patients. The patients were randomly divided into two groups: 23 received the regular 20% fat emulsion formulation, and 27 received a 2% formulation enriched 10-fold with PLs but containing the same amount of triglycerides. All patients gained weight and improved their activity level. Those receiving the high-PL composition showed increased serum CHOL concentrations (from 147 to 241 mg/dL; P < 0.01), but no increase was seen in the number of CD4 cells or improvement in immune function. HIV infectivity was not modified. Patients receiving regular PLs had significantly decreased (P < 0.02) IgA concentrations (from 776 to 300 mg/dL) and improved mitogen response to phytohemagglutinin and to concanavalin A. This formula, too, had no effect on HIV infectivity. We conclude that standard parenteral nutritional influences the nutritional and immune status of malnourished AIDS patients. A PL-enriched parenteral formulation can trap CHOL, but it does not affect the immune profile or HIV infectivity in patients with advanced disease.

Phospholipid-rich particles in commercial parenteral fat emulsions. An overview

In parenteral nutrition, the infusion of a fat EMU supplies both concentrated energy and covers the essential fatty acid requirements, the basic objective being to mimic as well as possible the input of chylomicrons into the blood. This objective is well met by the TAGRP of the EMU, which behave as true chylomicrons. However, commercial EMU also contain an excess of emulsifier in the form of PLRP. The number of these PLRP depends directly on the PL/TAG ratio of the EMU. They differ from the TAGRP by their composition (PL vs TAG and PL), their structure (PL in bilayer versus monolayer), and their granulometry (mean diameter 70-100 nm for PL vs 200-500 nm). The metabolic fate of the PLRP is similar in several ways to that of the TAGRP: exchanges of PL with the PL of the different cellular membranes and of the lipoproteins; captation of free CH from these same structures; and enrichment in apolipoproteins. However, because the TAGRP are the preferred substrates of the lipolytic enzymes, their clearance is much more rapid (half-life < 1 h) than that of the PLRP. As the infusion is continued, the PLRP end up accumulating and being transformed into LP-X (free CH/PL = 1; half-life of several days). As soon as the EMU is infused, the PLRP enter into competition with the TAGRP, in the lipolysis process as well as for sites of binding and for catabolism. The sites for catabolism of the two types of PAR are not the same: adipose tissues and muscles utilize the fatty acids and monoacylglycerols released by the lipolysis of the TAGRP; hepatocytes take up their remnants; the RES and the hepatocytes participate in the catabolism of the PLRP and the LP-X. Thus, prolonged infusion of EMU rich in PLRP leads to a hypercholesterolemia, or at least a dyslipoproteinemia, due to elevated LP-X, associated with a depletion of cells in CH, stimulating thus tissue cholesterogenesis. However, parenteral nutrition has evolved towards the utilization of EMU with a low PL/TAG ratio (availability of 30% formula) and less rapid delivery. For these reasons, the hypercholesterolemias that used to be observed with the 10% EMU have become much less spectacular or have even disappeared. It is interesting to note that patients on prolonged TPN, in particular those with a short small intestine, have weak cholesterolemia, reflecting a lowering of HDL and LDL not masked by elevated LP-X. At present, it seems difficult to produce sufficiently stable parenteral EMU devoid of PLRP. Notwithstanding, all the observations made since the introduction of the EMU in TPN are in favour of the use of PLRP-poor EMU. It is clear that the 10% formulas, and generally those with a PL/TAG ratio of 12/100, are ill-advised, especially in patients with a retarded clearance of circulating lipids.

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.

Effects of intravenously infused egg phospholipids on lipid and lipoprotein metabolism in postoperative trauma

Lipid emulsions contain not only triglyceride (TG)-rich particles but also phospholipid (PL)-rich particles that are believed to trap free cholesterol and apoprotein E, when they are infused in excess. The present study was designed to evaluate the effects of such abnormal PL-rich particles on lipid metabolism during a 5-day infusion in man. Eighteen patients undergoing esophagectomy were evenly randomized to receive intravenously during 5 days 1.75 g.kg-1.d-1 long-chain TG from either a 10% lipid emulsion with a PL/TG weight ratio of 0.12 (group A), a 10% emulsion with a PL/TG weight ratio of 0.06 (group B), or a 20% emulsion with a PL/TG weight ratio of 0.06 (group C). Plasma PL, free cholesterol, and apoprotein E increased progressively in group A (4.1 +/- 0.3 mmol/L, 2.4 +/- 0.3 mmol/L, and 0.089 +/- 0.012 g/L on day 5, respectively) but not in groups B (2.7 +/- 0.3 mmol/L, 1.3 +/- 0.2 mmol/L, and 0.048 +/- 0.007 g/L) and C (2.4 +/- 0.2 mmol/L, 1.2 +/- 0.1 mmol/L, and 0.050 +/- 0.006 g/L). Free fatty acids and TGs remained constant and similar in each group postoperatively. After fat infusion had been stopped at the end of the fifth day, the elimination of plasma TGs over the next 4 hours was comparable in the three groups. We conclude that excess egg PLs induce alterations of plasma lipids even within a few days.

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.

Lipomatous hypertrophy of the cardiac interatrial septum: an unusual complication in long-term home parenteral nutrition in adult patients

The aim of this study was to report unusual echocardiographic findings in patients on long-term home parenteral nutrition suggesting lipomatous hypertrophy of the cardiac interatrial septum. Seven patients (two women and five men, mean age 58 years) were prospectively evaluated by two-dimensional echocardiography before and during home parenteral nutrition for severe short-bowel syndrome. Parenteral caloric intake was 33 +/- 4 kcal/kg per day (mean +/- SD), with a mean supply of lipid emulsion of 1 g/kg per day. The first echocardiography, performed before initiation of home parenteral nutrition, was normal in the seven patients. The second echocardiography, performed 5 to 43 months (mean 20 months) later, revealed a significant increase of the thickness of the atrial septum in all patients (+8.3 +/- 3.6 mm; p less than 0.01), consistent with the diagnosis of lipomatous hypertrophy in four patients, and moderate fat accumulation in two others. The septum thickness measured after the nutritional support period was significantly correlated (p less than 0.05) with the total amount of nutrient and lipid infused. Cardiac nuclear magnetic resonance imaging was performed in two patients; it suggested the adipose nature of interatrial septum deposit. None of the patients developed clinical or electrocardiographic symptoms during the period of nutrition. We suggest that patients undergoing long-term home parenteral nutrition be screened for this new and unusual cardiac abnormality. Whether the latter might have clinical consequences in these patients remains to be determined.

The effect of taurine on the cholestatic potential of sulfated lithocholate and its conjugates

The present study was aimed at determining whether the protection by taurine of lithocholate-sulfate-induced cholestasis is mediated by conjugation or by direct effect of the amino acid on bile formation. Injection of free and conjugated (glycine and taurine) sulfated lithocholate in guinea pigs significantly reduced the secretion rate of non-sulfated bile acids in bile. There was no decrease in bile flow after the injection of taurine-conjugated sulfated lithocholate, which was completely recovered in bile within 60 min. In contrast, injection of sulfated lithocholate and its glycine conjugate led to a marked decrease in bile flow, and neither one was significantly recovered in bile. In addition, both caused morphological changes in the liver, characterized by the accumulation of cytoplasmic vacuoles with lamellated myelin figures characteristic of phospholipidosis. Pretreatment with taurine (0.5% in drinking water for 3 days) prevented both the drop in bile flow and the histological changes in the liver, suggesting that conjugation with taurine removed the cholestatic potential of sulfated lithocholate. However, since taurine was effective not only in preventing cholestasis induced by the free form of sulfated lithocholate but also against its glycine conjugate, these results suggest that other mechanisms in addition to conjugate must be involved.

Selenium status prior to and during one month total parenteral nutrition in gastroenterological patients: A randomised study of two dosages of Se supplementation

13 consecutive adult gastroenterological patients with non-malignant disease who were candidates for total parenteral nutrition (TPN), and who had mild protein-energy malnutrition (82 +/- 3% of ideal body weight, serum albumin 32 +/- 2 g/l, mean +/- SEM) were found to have, prior to TPN, a Selenium level 50% less than controls (p < 0.001) as assayed by Se and glutathione peroxidase (GSHPx) in plasma and erythrocytes. Compared with other trace metals and minerals, eg, Mn, Zn and Cu, depletion of Selenium was the most marked in this population. Patients were randomised to be supplemented with either 100 or 200 microg/d of sodium-selenite, equal to 32 microg (0.4 micromol) or 64 microg (0.8 micromol) of selenium, in two cross-over periods of TPN, each of two weeks. In this short term study, significant increases in the four measurements of Se status (p < 0.05) were seen in all patients, but there was no difference between those receiving the high or low dose of the element. GSHPx in plasma was normalised within 1 month whereas the increase seen in the erythrocyte pool was consistent with a 4-month half-life. Pooled Se values for patients and controls showed logarithmic correlations between Se and GSHPx in erythrocytes (p < 0.001) and plasma (p < 0.01). Changes in GSHPx provided further evidence of Se depletion in our patients. This study suggests that malnourished gastroenterological patients receiving TPN require Se supplements and that 100 microg (0.4 micromol)/d of sodium-selenite is adequate for most patients since there was no additional benefit from the higher dose of 200 microg (0.8 micromol).

Intrahepatic cholestasis and phospholipidosis associated with the use of trimethoprim-sulfamethoxazole

Although liver injury after administration of the trimethoprim-sulfamethoxazole combination is rare, hepatocellular necrosis and cholestasis have developed in a few cases. We describe a patient who developed a severe, prolonged cholestatic reaction after trimethoprim-sulfamethoxazole administration. The findings from serial liver biopsy samples showed characteristic abnormalities of phospholipidosis that have not been previously described for trimethoprim-sulfamethoxazole-related hepatic injury. The most prominent finding on electron microscopic evaluation of the liver was the presence of prominent hepatocyte lysosomal inclusions characterized by concentric arrangements of membranous and lamellated structures. The patient improved after several courses of exchange plasmapheresis, which may have assisted in the removal of toxic drug-lipid complexes. The pathogenesis of this acquired secondary phospholipidosis is unknown. Possible mechanisms include generation of highly lipid-soluble metabolites and inhibition of the lysosomal enzyme phospholipase A1.