Dyslipoproteinaemia of liver disease

A High-Throughput NMR Method for Lipoprotein-X Quantification

Lipoprotein X (LP-X) is an abnormal cholesterol-rich lipoprotein particle that accumulates in patients with cholestatic liver disease and familial lecithin-cholesterol acyltransferase deficiency (FLD). Because there are no high-throughput diagnostic tests for its detection, a proton nuclear magnetic resonance (NMR) spectroscopy-based method was developed for use on a clinical NMR analyzer commonly used for the quantification of lipoproteins and other cardiovascular biomarkers. The LP-X assay was linear from 89 to 1615 mg/dL (cholesterol units) and had a functional sensitivity of 44 mg/dL. The intra-assay coefficient of variation (CV) varied between 1.8 and 11.8%, depending on the value of LP-X, whereas the inter-assay CV varied between 1.5 and 15.4%. The assay showed no interference with bilirubin levels up to 317 mg/dL and was also unaffected by hemolysis for hemoglobin values up to 216 mg/dL. Samples were stable when stored for up to 6 days at 4 °C but were not stable when frozen. In a large general population cohort (n = 277,000), LP-X was detected in only 50 subjects. The majority of LP-X positive cases had liver disease (64%), and in seven cases, had genetic FLD (14%). In summary, we describe a new NMR-based assay for LP-X, which can be readily implemented for routine clinical laboratory testing.

Adrenal insufficiency in cirrhosis

Hypothalamus-pituitary-adrenal axis assessment in patients with cirrhosis is challenging. The phenotype of fatigue, hypotension, electrolyte disarray, and abdominal pain characterizing primary adrenal insufficiency (AI) overlaps significantly with decompensated liver disease. Reliance on total cortisol assays in hypoproteinemic states is problematic, yet abnormal stimulated levels in cirrhosis are associated with poor clinical outcomes. Alternative measures including free plasma or salivary cortisol levels have theoretical merit but are limited by unclear prognostic significance and undefined cirrhosis-specific reference ranges. Further complicating matters is that AI in cirrhosis represents a spectrum of impairment. Although absolute cortisol deficiency can occur, this represents a minority of cases. Instead, there is an emerging concept that cirrhosis, with or without critical illness, may induce a “relative” cortisol deficiency during times of stress. In addition, the limitations posed by decreased synthesis of binding globulins in cirrhosis necessitate re-evaluation of traditional AI diagnostic thresholds.

FXR in liver physiology: Multiple faces to regulate liver metabolism

The liver is the central metabolic hub which coordinates nutritional inputs and metabolic outputs. Food intake releases bile acids which can be sensed by the bile acid receptor FXR in the liver and the intestine. Hepatic and intestinal FXR coordinately regulate postprandial nutrient disposal in a network of interacting metabolic nuclear receptors. In this review we summarize and update the "classical roles" of FXR as a central integrator of the feeding state response, which orchestrates the metabolic processing of carbohydrates, lipids, proteins and bile acids. We also discuss more recent and less well studied FXR effects on amino acid, protein metabolism, autophagic turnover and inflammation. In addition, we summarize the recent understanding of how FXR signaling is affected by posttranslational modifications and by different FXR isoforms. These modifications and variations in FXR signaling might be considered when FXR is targeted pharmaceutically in clinical applications.

Secondary dyslipidemia: its treatments and association with atherosclerosis

Dyslipidemia is classified into primary and secondary types. Primary dyslipidemia is basically inherited and caused by single or multiple gene mutations that result in either overproduction or defective clearance of triglycerides and cholesterol. Secondary dyslipidemia is caused by unhealthy lifestyle factors and acquired medical conditions, including underlying diseases and applied drugs. Secondary dyslipidemia accounts for approximately 30-40% of all dyslipidemia. Secondary dyslipidemia should be treated by finding and addressing its causative diseases or drugs. For example, treatment of secondary dyslipidemia, such as hyperlipidemia due to hypothyroidism, by using statin without controlling hypothyroidism, may lead to myopathy and serious adverse events such as rhabdomyolysis. Differential diagnosis of secondary dyslipidemia is very important for safe and effective treatment. Here, we describe an overview about diseases and drugs that interfere with lipid metabolism leading to secondary dyslipidemia. Further, we show the association of each secondary dyslipidemia with atherosclerosis and the treatments for such dyslipidemia.

The Pattern of Dyslipidemia in Chronic Liver Disease Patients

Introduction Patients with chronic liver disease are expected to report derangements in serum lipid profiles. Lipid profile monitoring is not a part of the routine management of these patients in our hospital. Few recent studies show how lipid profile varies with the severity of disease and should be considered in the management planning of such patients. The objective of this study was to determine the pattern of dyslipidemia in chronic liver disease patients. Materials and methods A cross-sectional study was conducted involving 171 patients of all genders aged between 18 years and 60 years presenting with chronic liver disease with disease severity graded on Child-Pugh class as A, B, and C. Lipid profile was acquired in all these patients and was compared across various subgroups. Individual serum lipid parameters were graded as normal, high, or very high. Each patient was required to provide written informed consent. Statistical Package for Social Sciences (SPSS) version 21.0 (IBM Corp. Armonk, NY) was used to analyze data statistically, taking a p-value of ≤0.05 as significant. Results The mean age of patients was 51.2±7.3 years. The male to female ratio came out to be 1.5:1, with 103 (60.2%) male and 68 (39.8%) female patients included in the study. The disease was classified as Child-Pugh A in 20 (11.7%) patients, Child-Pugh B in 67 (39.2%) patients, and Child-Pugh C in 84 (49.1%) patients. Forty-four (25.7%) patients were hypertensive while 62 (36.3%) were diabetic. The mean body mass index (BMI) of these patients was 25.9±2.4 kg/m2. Mean serum values among Child-Pugh A, Child-Pugh B, and Child-Pugh C of low-density lipoproteins (LDL) (113.15±14.08 vs. 95.58±14.25 vs. 53.46±5.90 mg/dl; p-value 0.001), high-density lipoproteins (HDL) (50.60±3.19 vs. 40.70±2.95 vs. 35.40±3.88 mg/dl; p-value 0.001), total cholesterol (174.20±17.33 vs. 164.00±17.82 vs. 128.64±24.73 mg/dl; p-value 0.001), and triglycerides (127.15±8.98 vs. 100.84±27.12 vs. 93.36±25.56 mg/dl; p-value 0.001) decreased significantly with increasing severity of disease. Nineteen (11.1%) patients had hyperlipidemia (serum values of two or more parameters above normal) while 152 (88.9%) patients had normal lipid profile. When stratified, no statistically significant difference was found in the frequency of hyperlipidemia across various subgroups based on the patient's gender, age, duration, and severity of the disease, BMI, or diabetic and hypertensive status. Conclusions A substantial proportion of patients with chronic liver disease had hyperlipidemia which varied with the severity of disease on Child-Pugh classification. Routine monitoring of the lipid profile of such patients is necessary for timely identification and management of dyslipidemia to improve the outcome of such patients. It also suggests an important role of lipid profile in the risk stratification and treatment of chronic liver disease patients and warrants further studies in this regard.

Characterization of LP-Z Lipoprotein Particles and Quantification in Subjects with Liver Disease Using a Newly Developed NMR-Based Assay

Background: Lipoprotein particles with abnormal compositions, such as lipoprotein X (LP-X) and lipoprotein Z (LP-Z), have been described in cases of obstructive jaundice and cholestasis. The study objectives were to: (1) develop an NMR-based assay for quantification of plasma/serum LP-Z particles, (2) evaluate the assay performance, (3) isolate LP-Z particles and characterize them by lipidomic and proteomic analysis, and (4) quantify LP-Z in subjects with various liver diseases. Methods: Assay performance was assessed for linearity, sensitivity, and precision. Mass spectroscopy was used to characterize the protein and lipid content of isolated LP-Z particles. Results: The assay showed good linearity and precision (2.5–6.3%). Lipid analyses revealed that LP-Z particles exhibit lower cholesteryl esters and higher free cholesterol, bile acids, acylcarnitines, diacylglycerides, dihexosylceramides, lysophosphatidylcholines, phosphatidylcholines, triacylglycerides, and fatty acids than low-density lipoprotein (LDL) particles. A proteomic analysis revealed that LP-Z have one copy of apolipoprotein B per particle such as LDL, but less apolipoprotein (apo)A-I, apoC3, apoA-IV and apoC2 and more complement C3. LP-Z were not detected in healthy volunteers or subjects with primary biliary cholangitis, primary sclerosing cholangitis, autoimmune hepatitis, or type 2 diabetes. LP-Z were detected in some, but not all, subjects with hypertriglyceridemia, and were high in some subjects with alcoholic liver disease. Conclusions: LP-Z differ significantly in their lipid and protein content from LDL. Further studies are needed to fully understand the pathophysiological reason for the enhanced presence of LP-Z particles in patients with cholestasis and alcoholic liver disease.

Coenzyme Q10 attenuates rat hepatocarcinogenesis via the reduction of CD59 expression and phospholipase D activity

The current study aimed to test the profile of serum lipids, phospholipase D (PLD) activity, and CD59 expression pattern in rat hepatocellular carcinoma (HCC) after therapeutic treatment with Coenzyme Q10 (CoQ10). Three rat groups were allocated as normal control, untreated HCC, and treated HCC (HCC + CoQ10). The levels of serum α-fetoprotein (AFP) and tumour necrosis factor (TNF)-α were assessed using enzyme-linked immunosorbent assay (ELISA), while proliferating cell nuclear antigen (PCNA) was detected using immunohistochemistry (IHC). Serum lipids, classical (CH50), and alternative (APH50) pathways of complement activation, the liver cell HMG-CoA reductase (HMGCR), and PLD activities were assayed colorimetrically. The protein expression of CD59, scavenger receptor class B type 1 (SRB1), B cell lymphoma-2 (Bcl2), and cleaved Caspase-3 (Casp-3) were detected using western blotting, while the level of serum CD59 (sCD59) was assessed using dot-blot. CoQ10 reduced the cell proliferation, histological alterations, and the levels of AFP and TNF-α but increased lipids, CH50, and sCD59 in serum. In the liver cell, CoQ10 decreased and increased PLD and HMGCR enzyme activities, respectively. In addition, reduction of liver CD59, Bcl2, and SRB1 vs increased cleaved Casp-3 expressions was observed. Statistical correlation indicated an inverse relationship between CH50 and each of CD59 expression and PLD activity after treatment with CoQ10. In conclusion, CoQ10 could protect against rat HCC through increased lipids and the reduction of CD59 expression and PLD activity. SIGNIFICANCE OF THE STUDY: To our knowledge, this study is the first to describe the attenuating effect of antitumour natural product like Coenzyme Q10 (CoQ10) via the reduction of CD59 expression and phospholipase D (PLD) activity. This illustrates the important role of CD59 and PLD in relation to lipids in cancer prevention.

Lp8 is potentially associated with partial lecithin:cholesterol acyltransferase deficiency in a patient with primary biliary cirrhosis

BACKGROUND

The significance of Lp8, that is, abnormal lipoprotein(s) detected in fraction 8 by combined high-performance liquid chromatography/gel filtration column in patients with familial lecithin:cholesterol acyltransferase (LCAT) syndrome, in relation to the severity of LCAT deficiency has not been analyzed.

OBJECTIVE

We have studied Lp8 in a patient with primary biliary cirrhosis.

METHODS

Plasma lipoproteins were analyzed using high-performance liquid chromatography/gel filtration column in the course of treatment of a 47-year-old female patient with primary biliary cirrhosis.

RESULTS

Electrophoretic lipoprotein analyses showed massive accumulation of abnormal ß- and preß-lipoproteins with a minor lipoprotein fraction at a position near the cathode corresponding to Lp-X, on day A (status: hypercholesterolemia, LCAT activity undetectable). Chromatographic lipoprotein subfraction analysis revealed free cholesterol- and phospholipid-rich lipoproteins in fractions 1-6, corresponding to chylomicrons and very low-density lipoprotein, and phospholipid- and triglyceride-rich lipoproteins with increased free cholesterol, that is, Lp8, in fractions 7-9 (corresponding to low-density lipoprotein). On day B, after additional treatment for 7 months (status: almost normolipidemia, decreased LCAT activity), although the abnormal lipoprotein and the lipoproteins in fractions 1-6, were drastically decreased, the presence of Lp8 persisted.

CONCLUSIONS

Lp8 likely is a minor abnormal lipoprotein fraction in patients with mildly decreased secondary LCAT activity, as well as with severely reduced primary LCAT activity.

Lipid profiling of lipoprotein X: Implications for dyslipidemia in cholestasis

Lipoprotein X (Lp-X) is an abnormal lipoprotein that may typically be formed in intra- and extrahepatic cholestasis and potentially interfere with lipid analysis in the routine lab. To gain insight into lipid class and species composition, Lp-X, LDL and HDL from cholestatic and control serum samples were subjected to mass spectrometric analysis including phospholipids (PL), sphingolipids, free cholesterol (FC), cholesteryl esters (CE) and bile acids. Our analysis of Lp-X revealed a content of 46% FC, 49% PL with 34% phosphatidylcholine (PC) as main PL component. The lipid species pattern of Lp-X showed remarkable high fractions of mono-unsaturated species including PC 32:1 and PC 34:1 and phosphatidylethanolamine (PE) 32:1 and 34:1. LDL and HDL lipid composition in the same specimens strongly reflected the lipid composition of Lp-X with increased PC 32:1, PC 34:1, PE 32:1, PE 34:1 and FC accompanied by decreased CE compared to controls. Comparison of Lp-X and biliary lipid composition clearly indicates that Lp-X does not originate from a sole release of bile lipids. Moreover, these data present evidence for increased hepatic fatty acid and PL synthesis which may represent a reaction to high hepatic FC level observed during cholestasis.

Newborn APOE genotype influences maternal lipid profile and the severity of high-risk pregnancy - preeclampsia: Interaction with maternal genotypes as a modulating risk factor in preeclampsia

AIM

To establish the role of the interaction between maternal and newborn apolipoprotein E (APOE) genotypes on the risk, lipid profile and prognosis of preeclampsia (PE).

MATERIALS AND METHODS

Forty-seven preeclamptic women and 94 normotensive pregnant women and their newborns were genotyped for APOE using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.

RESULTS

Maternal APOE-ε4 allele was associated with an about eight times higher risk of PE (adjusted OR = 8.4, 95% CI: 2.51-28.17, p = 0.001). The multivariate logistic regression model showed that the newborn APOE-ε4 allele was associated with an about six times higher risk of PE (adjusted OR = 5.6, 95% CI: 2.09-15.21, p = 0.001) for the given gestational age levels. Pregnant women with severe PE whose newborns carried the APOE-ε4 allele delivered at earlier gestational ages neonates with a lower birth weight compared to pregnant women with newborns negative for this allele. Higher TG and LDL-C levels and lower HDL-C levels were found in pregnant women with severe PE whose newborns were carriers of the APOE-ε4 allele compared to preeclamptic women whose newborns were carriers of the ε3/ε3 genotype. If we checked the combined effect of the mother/newborn genotypes on the risk of PE, we found that the risk to develop PE was 15.4-fold (p < 0.001) increased if mothers or newborns were carriers of the APOE-ε4 allele. The risk increased to 20.02 (p < 0.001) if both the mother and newborn were carriers of the APOE-ε4 allele.

CONCLUSIONS

Our study confirms the maternal/newborn APOE genotype interaction influences the risk for PE, as well as prognosis and lipid profile.

Primary Biliary Cirrhosis and Primary Sclerosing Cholangitis: a Review Featuring a Women's Health Perspective

Primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) are two major types of chronic cholestatic liver disease. Each disorder has distinguishing features and variable progression, but both may ultimately result in cirrhosis and hepatic failure. The following offers a review of PBC and PSC, beginning with a general overview of disease etiology, pathogenesis, diagnosis, clinical features, natural course, and treatment. In addition to commonly associated manifestations of fatigue, pruritus, and fat-soluble vitamin deficiency, select disease-related topics pertaining to women's health are discussed including metabolic bone disease, hyperlipidemia and cardiovascular risk, and pregnancy-related issues influencing maternal disease course and birth outcomes. This comprehensive review of PBC and PSC highlights some unique clinical considerations in the care of female patients with cholestatic liver disease.

Extreme hypercholesterolemia presenting with pseudohyponatremia - a case report and review of the literature

Pseudohyponatremia has been reported in association with severe hypertriglyceridemia and hyperparaproteinemia, but its association with severe hypercholesterolemia is not well-known. We report a 43-year-old woman with refractory primary biliary cirrhosis who presented with asymptomatic hyponatremia (121 mmol/L; normal range: 135-145 mmol/L). She was ultimately found to have a total serum cholesterol level of 2415 mg/dL (normal range: 120-199 mg/dL) - secondary to accumulation of lipoprotein-X-causing pseudohyponatremia. The diagnosis was confirmed by measurement of serum osmolality (296 mOsm/kg H2O; normal range: 270-300 mOsm/kg H2O) and serum sodium by direct potentiometry (141 mmol/L). Furthermore, following 16 sessions of plasmapheresis over a 4-month period, there was marked lowering of serum cholesterol to 200 mg/dL and normalization of serum sodium (139 mmol/L) as measured by indirect potentiometry. This case shows that extreme hypercholesterolemia from elevation of lipoprotein-X particles in cholestasis can be a rare cause of pseudohyponatremia. It highlights the need to measure serum sodium with direct potentiometry in the setting of extreme hypercholesterolemia and consider this possibility before initiating treatment of hyponatremia.

Low levels of blood lipids are associated with etiology and lethal outcome in acute liver failure

BACKGROUND/AIMS

Emerging data links different aspects of lipid metabolism to liver regeneration. In patients with acute liver failure (ALF), low levels of lipids may correlate with disease severity. Thus, we determined whether there is an etiology-specific link between lipid levels in patients suffering from ALF and aimed to investigate an effect of lipid levels on the prognosis of ALF.

METHODS

In this retrospective single center study, we reviewed 89 consecutive ALF patients, who met the criteria of the "Acute Liver Failure Study Group". Patient characteristics, clinical data and laboratory parameters were individually analyzed at admission and correlated with the patients' outcome after a four week follow up. Possible endpoints were either discharge, or death or liver transplantation.

RESULTS

High-density lipoprotein (HDL), cholesterol and triglyceride levels were significantly lower in patients who died or required a liver transplant. HDL levels were significantly higher in patients with ALF caused by acetaminophen intoxication, compared to fulminant HBV infection or drug induced liver injury. HDL levels correlated with hepatic injury by ALT levels, and Albumin, and inversely correlated with the MELD score, INR, and bilirubin.

CONCLUSION

In our cohort of patients with ALF, we could show that HDL and cholesterol are suppressed. In addition novel etiology specific patterns between acteminophen and non-acteminophen induced liver failure were detected for serum lipid components. Further studies are needed to address the role of cholesterol and lipid metabolism and the according pathways in different etiologies of ALF.

Identification of serum protein biomarkers in biliary atresia by mass spectrometry and enzyme-linked immunosorbent assay

OBJECTIVE

There is an urgent need to identify noninvasive and convenient biomarkers for early diagnosis of biliary atresia (BA). The aim of the present study was to identify potential protein biomarkers for BA.

METHODS

Serum samples from 42 infants with BA, 38 infants with non-BA neonatal cholestasis (NC), and 36 healthy controls (HC) were randomly divided into a training set and a test set. Serum proteomic profiles were measured using surface-enhanced desorption/ionization time-of-flight mass spectrometry. Candidate biomarkers were purified using high-performance liquid chromatography, identified using liquid chromatography tandem mass spectrometry, and validated using enzyme-linked immunosorbent assay.

RESULTS

A total of 2 protein peaks (m/z with 8697 and 9098  Da) with differential expression levels were found using surface-enhanced desorption/ionization time-of-flight mass spectrometry. These peaks were then analyzed by a support vector machine to construct a classification model in the training set. The sensitivity and specificity of the model were 94.1% and 91.8%, respectively, in the test set. One candidate biomarker (9098  Da) was identified as Apo C-II, and was found to be downregulated in BA samples compared with HC samples, and upregulated in BA samples compared with NC samples. The other candidate biomarker (8697  Da) was identified as Apo C-III, and was found to be upregulated in BA compared with NC and HC.

CONCLUSIONS

Apo C-II and Apo C-III may be potential protein biomarkers of BA and may be useful in distinguishing infants with BA from healthy and NC infants. Further studies with additional populations or using prediagnostic serum are needed to confirm the importance of these findings as diagnostic markers of infants with BA.

A case of type 2 diabetes and metastatic liver cancer exhibiting hypercholesterolemia with abnormal lipoproteins

Although the appearance of abnormal lipoproteins in liver diseases is well known, the precise analyses of abnormal lipoproteins remain elusive. Here, we report a 71-year-old woman with type 2 diabetes whose serum cholesterol levels were elevated to 560 mg/dL over a 4-month period. High-performance liquid chromatography demonstrated the presence of lipoprotein-X and lipoprotein-Y and sigmoid colon cancer and multiple liver metastases were found by colonoscopy and computed tomography. Remission of the primary colon cancer and liver lesions was achieved by chemotherapy with oxaliplatin and fluorouracil and her serum cholesterol went back to basal levels associated with the disappearance of abnormal lipoproteins.

Primary biliary cirrhosis is associated with oxidative stress and endothelial dysfunction but not increased cardiovascular risk

AIM

  Primary biliary cirrhosis (PBC) is a chronic cholestatic disease which is associated with hypercholesterolaemia. Further, cholestatic diseases are associated with deficiencies of anti-oxidant vitamins. Despite these associations PBC is not associated with an increase in cardiovascular mortality. The aim of this study is to assess if primary biliary cirrhosis is associated with oxidative stress, endothelial dysfunction and alteration of vascular compliance which is a surrogate marker for cardiovascular risk.

METHODS

  Fifty-one PBC patients and 34 control subjects were studied. Lipid soluble vitamins A, and E in addition to ascorbate and carotenoids were measured to assess anti-oxidant status. C-reactive protein, hydroperoxides and adhesion molecules sICAM-l/sVCAM-l were assessed as serological measures of endothelial function. Finally, measures of vascular compliance were assessed by applanation tonometer.

RESULTS

  CRP, sICAM and sVCAM were all significantly higher in PBC patients (469.14 vs 207.13, P < 0.001; 768.12 vs 308.03,P < 0.001; 708.40 vs 461.31, P < 0.001) whilst anti-oxidant vitamin levels were lower in PBC patients, with ascorbate, vitamin E and vitamin A all significantly lower in PBC patients (39.91 vs 72.68, P < 0.001; 2.63 vs 3.14, P = 0.02; 1.08 vs 1.81, P < 0.001). Despite these findings PBC patients have a lower pulse wave velocity than control subjects (8.22 m/s vs 8.78 m/s, P = 0.022).

CONCLUSION

  PBC patients appear to have reduced vascular risk as assessed by pulse wave velocity but concurrently have evidence of endothelial dysfunction, inflammation and anti-oxidant deficiency.

Decreased paraoxonase-1 activity is associated with alterations of high-density lipoprotein particles in chronic liver impairment

Background

Paraoxonase-1 (PON1), a lactonase synthesized by the liver, circulates in blood bound to high-density lipoproteins (HDL). This enzyme is thought to degrade oxidized phospholipids and play an important role in the organism's antioxidant and anti-inflammatory system. Chronic liver diseases are characterized by decreased serum PON1 activity. The aim of the present study was to investigate the compositional changes in HDL that could influence PON1 activity in liver impairment.

Methods

The study was performed in samples from five patients with advanced liver cirrhosis and with preserved renal function, chosen on the basis of having low serum PON1 activity and high serum PON1 concentration. As a control group, we accessed five healthy volunteers from among our hospital staff. Lipid and protein compositional analysis of lipoprotein particles were done by high-performance liquid chromatography, gel electrophoresis, and Western-Blot.

Results

HDL particles from cirrhotic patients had an increased phospholipid content that was inversely correlated to PON1 activity. The HDL particles contained high levels of PON1 that corresponded, in part, to an immunoreactive protein of high molecular weight (55 kDa) not present in control subjects. This protein was identified as glycosylated PON1 and was also present in biopsies from patients with steatosis and from rats with CCl₄-induced hepatic impairment. These changes were associated with an increased plasma concentration of markers of oxidative stress, inflammation and fibrogenesis.

Conclusion

Abnormalities in the composition of lipids and proteins of HDL particles, including PON1 glycosylation, are associated with the decrease in serum PON1 activity in patients with liver disease. These alterations may adversely affect the protective role of HDL against oxidative stress and inflammation in these patients.

Serum markers may distinguish biliary atresia from other forms of neonatal cholestasis

BACKGROUND

Biliary atresia (BA) is the most serious liver disease in infants. Diagnosis currently depends on surgical exploration of the biliary tree. Noninvasive tests that distinguish BA from other types of neonatal liver disease are not available.

PATIENTS AND METHODS

To identify potential serum biomarkers that classify children with neonatal cholestasis, we performed 2-dimensional difference gel electrophoresis, statistical analysis, and tandem mass spectrometry using serum samples from 19 infants with BA and 19 infants with non-BA neonatal cholestasis.

RESULTS

Eleven potential serum biomarkers were found that could in combination classify children with neonatal cholestasis.

CONCLUSIONS

Although no single biomarker or imaging test adequately distinguishes BA from other types of neonatal cholestasis, combinations of biomarkers, imaging tests, and noninvasive clinical criteria should be further explored as potential tests for rapid and accurate diagnosis of BA.

Impaired plasma lipid profiles in acute hepatitis

The present study examined plasma lipid profiles in thirty patients suffered from acute viral hepatitis. Patients' blood samples were collected at both the debut and recovery of diseases. Thirty sex and age matched normal subjects were included as controls. Plasma total triglycerides (TG), total cholesterol, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoprotein AI (ApoAI), apolipoprotein B (ApoB), lipoprotein (a) (Lp(a)), blood coagulation status including prothrombin complex activity and activated partial tromboplastin time (APTT), and hepatic functions were determined by the automatic biochemical analytical instrument. It demonstrated that plasma levels of total cholesterol, HDL-C and apoAI were significantly lower in the patients at the acute phase of hepatitis than those in normal subjects, whereas plasma levels of TG and LDL-C were obviously higher in the patients than in normal subjects (P < 0.05). Moreover, we demonstrated that patients' plasma levels of total cholesterol, LDL-C, HDL-C and apoAI were lower at the active phase of the diseases than at the recovering phase, which indicating that acute liver damage could significant influence lipid metabolism in vivo. No pathological changes of blood coagulation status occurred in these patients during the study as all selected patients had moderate hepatitis. It may conclude that examinations of plasma lipid profile could be considered as a clinical index to reflect liver damage in the active phase of hepatitis.

Lipid profile in children with acute viral hepatitis A

BACKGROUND

Most of the knowledge about lipid parameters in acute hepatitis is originated from adult studies. In this study, the authors investigated lipid profile of children with acute hepatitis A (AVH) at diagnosis and recovery in order to observe the behavior of lipid parameters in such children.

METHODS

A total of 28 children (mean age, 8.2 +/- 2.7 years) with AVH and 20 gender and age-matched healthy children were included. In addition to the routine tests, triglyceride, cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), plasma apo A-I and apo B were studied at diagnosis and recovery.

RESULTS

Serum triglyceride and apo B level was higher, and apo A-I level was lower in patients compared to healthy children (P < 0.01, <0.05 and <0.01, respectively). On admission, three children had fulminant hepatic failure (FHF). Serum lipid parameters were evaluated in respect with the presence of icterus and FHF, and found that apo A-I level was lower in icteric children and LDL and apo A-I were lower in FHF compared to others (P < 0.05, P < 0.01 and P < 0.05, respectively). At recovery, while triglyceride, cholesterol, LDL, and apo B decreased (P < 0.01), HDL and apo A-I increased (P < 0.01). Serum apo A-I level was inversely correlated with serum ammonia level but was positively correlated with serum albumin (P < 0.05).

CONCLUSIONS

It was shown that serum triglyceride and apo B level increased, but apo A-I level decreased in patients with AVH. While cholestasis lowers apo A-I level, severe hepatic damage lowers both apo A-I and LDL. These parameters return to normal levels within 30 days. An interesting relationship between ammonia and apo A-I deserves further investigations, speculatively focused on hepatocyte nuclear factor 4 alpha.

A comprehensive analysis of 12 thrombophilic mutations and related parameters in patients with inflammatory bowel disease: data from Turkey

BACKGROUND

Possible association of inflammatory bowel disease (IBD) with the most common inherited prothrombotic conditions has been the focus of many investigations. Advance in modern molecular biology is expanding the thrombophilia evaluation steadily. We tried to put forward a comprehensive thrombophilic profile in IBD and to see the probable role of this profile in pathogenesis.

METHODS

A total of 60 adults (33 patients and 27 healthy controls) were included. We used the CVD-StripAssay which is based on the reverse-hybridization principle to identify a total of 12 thrombophilic gene mutations: Factor V R506Q, Factor V H1299R, prothrombin G20210A, Factor XIII V34L, beta-Fibrinogen-455 G-A, PAI-1 4G/5G, platelet GPIIIa L33P, MTHFR C677T, MTHFR A1298C, ACE I/D, Apo B R3500Q and Apo E2/E3/E4, respectively. Besides, we evaluated many related blood parameters such as protein C, protein S, AT-III, IL-6, TNF-alpha, Apo-A1, Apo-B100, homocysteine (tHcy) etc. using commercially available assays.

RESULTS

The frequencies of genetic polymorphisms were found to be statistically insignificant among patients and controls, except for three: Beta-Fibrinogen-455G-A, MTHFR A1298C and ACE-I/D. Two patients with a history of deep venous thrombosis had more than one polymorphism. Patients with MTHFR C677T and MTHFR A1298C gene mutations had a similar mean tHcy levels with controls. Patients with Apolipoprotein B R3500Q and Apolipoprotein E4 gene mutations had similar mean LDL-cholesterol levels. Mean total cholesterol and triglyceride levels were similar in patients and controls of Apo E2, E3, E4 alleles.

CONCLUSION

Predominantly, the presence of genetic mutations that predispose to hypercoagulable states does not appear to be in correlation with IBD. There was a statistical difference between the proportions of the mutated allele frequencies of Beta-Fibrinogen-455G-A, MTHFR A1298C and ACE-I/D in IBD.

Primary biliary cirrhosis, hyperlipidemia, and atherosclerotic risk: a systematic review

Primary Biliary Cirrhosis (PBC) is a chronic, progressive liver disease associated with markedly elevated serum lipids, but it is not clear if PBC is associated with accelerated atherosclerosis. The present systematic review examined the relationship of PBC to atherosclerotic risk. The lipid abnormalities in PBC are complex, depend on the stage of hepatic dysfunction and affect most lipoprotein classes. Increased cholesterol levels in PBC are primarily due to LP-X, an abnormal LDL particle. LP-X has anti-atherogenic properties and may reduce the atherosclerotic risk. Few studies have examined coronary artery disease (CAD) events in PBC, and none have sufficient sample size of follow-up to determine CAD risk in PBC patients. Nevertheless, one study suggested that 12% of PBC patients died from circulatory system diseases suggesting that lipid treatment is appropriate in some patients. Additional larger scale, prospective studies are required to determine the necessity of lipid treatment in this patient group. In the interim, decisions on the use of lipid lowering agents depend largely on the prognosis of the PBC and physician and patient preference for treatment.

Expression patterns and action analysis of genes associated with drug-induced liver diseases during rat liver regeneration

AIM: To study the action of the genes associated with drug-induced liver diseases at the gene transcriptional level during liver regeneration (LR) in rats.

METHODS: The genes associated with drug-induced liver diseases were obtained by collecting the data from databases and literature, and the gene expression changes in the regenerating liver were checked by the Rat Genome 230 2.0 array.

RESULTS: The initial and total expression numbers of genes occurring in phases of 0.5-4 h after partial hepatectomy (PH), 4-6 h after PH (G0/G1 transition), 6-66 h after PH (cell proliferation), 66-168 h after PH (cell differentiation and structure-function reconstruction) were 21, 3, 9, 2 and 21, 9, 19, 18, respectively. It is illustrated that the associated genes were mainly triggered at the initial stage of LR and worked at different phases. According to their expression similarity, these genes were classified into 5 types: only up-regulated (12 genes), predominantly up-regulated (4 genes), only down-regulated (11 genes), predominantly down-regulated (3 genes), and approximately up-/down-regulated (2 genes). The total times of their up- and down-expression were 130 and 79, respectively, demonstrating that expression of most of the genes was increased during LR, while a few decreased. The cell physiological and biochemical activities during LR were staggered according to the time relevance and were diverse and complicated in gene expression patterns.

CONCLUSION: Drug metabolic capacity in regenerating liver was enhanced. Thirty-two genes play important roles during liver regeneration in rats.

Improved Specificity of a New Homogeneous Assay for LDL-Cholesterol in Serum with Abnormal Lipoproteins

Background: Although a homogeneous assay for serum LDL-cholesterol (LDL-C) has become a routine clinical procedure, problems remain in assay performance characteristics.

Methods: We examined the performance of a recently developed automated homogeneous assay (New-Daiichi assay) for serum LDL-C and compared the results with those obtained by the current homogeneous method (Denka-Seiken assay) or by ultracentrifugation as a control.

Results: The New-Daiichi assay showed satisfactory basic performance characteristics such as reproducibility, linearity, and stability. There was no interference in the assay by various substances examined. The LDL-C values obtained with this method correlated well with those obtained by ultracentrifugation. In samples from patients with obstructive jaundice, both methods detected cholesterol from abnormal lipoproteins (such as lipoprotein-X and -Y), but the New-Daiichi assay was less reactive and more specific for LDL-C.

Conclusion: The new method has improved performance for the accurate measurement of LDL-C in clinical practice.

Influence of liver cancer on lipid and lipoprotein metabolism

Liver plays a key role in the metabolism of plasma apolipoproteins, endogenous lipids and lipoproteins. Hepatocellular carcinoma (HCC) is one of the most common fatal malignant tumors in China and in other Southeast Asian countries. This has been attributed to the high incidence of hepatitis B infection. Hepatitis B proteins, such as the hepatitis B X protein (HBx) that is large hepatitis B surface protein could regulate transcription of many candidate genes for liver carcinogenesis. It has known that patients who suffered from acute hepatitis B could have lipid disorders such as decreased plasma level of high-density lipoproteins (HDL). Furthermore, aberrations of lipid metabolism are often seen in the chronic hepatitis B infection. Plasma lipid profiles could be changed under HCC. In majority of the reports in HCC, plasma levels of triglycerides (TG), cholesterol, free fatty acids (FFA), HDL, low-density lipoproteins (LDL), lipoprotein (a) (Lp(a)), apolipoprotein AI (apoAI) and apoB were slight to significantly decreased, however, in some cases plasma levels of TG and Lp(a) might be increased. It has been suggested that analysis of plasma levels of lipids, lipoproteins and apolipoproteins in the patients suffered from HCC reflects on the hepatic cellular impairment status. Studies revealed that alterations seen in the plasma levels of lipids, lipoproteins and apolipoproteins reflecting patients' pathologic conditions. Decreased serum levels of cholesterol and apoAI may indicate a poor prognosis. Human leukaemic cells and certain tumor tissues have a higher receptor-mediated uptake of HDL and LDL than the corresponding normal cells or tissues. LDL and HDL have therefore been proposed as a carrier for the water-insoluble anti-cancer agents.

Severe Hypercholesterolemia Associated with Decreased Hepatic Triglyceride Lipase Activity and Pseudohyponatremia in Patients after Allogeneic Stem Cell Transplantation

A 55-year-old woman with Ph-negative acute lymphoblastic leukemia in primary induction failure received allogeneic peripheral blood stem cell transplantation from her HLA-compatible sister. Pseudohyponatremia developed due to extreme hypercholesterolemia of 4091 mg/dL accompanied by lipoprotein X and lipoprotein Y. The hypercholesterolemia was caused by cholestasis due to chronic GVHD and ischemic cholangiopathy. In addition, we found that hepatic triglyceride lipase (HTGL) activity was severely decreased, which could be another novel factor causing extreme hypercholesterolemia after allogeneic transplantation. The total cholesterol has been gradually decreasing followed by the improvement of cholestasis with bezafibrate, ursodeoxycholic acid and prednisone treatments, and by a slight increase in HTGL-protein. To our knowledge, this is the first report to describe the association of decreased HTGL with extreme hypercholesterolemia after allogeneic transplantation.

Severe hypercholesterolemia mediated by lipoprotein X in patients with chronic graft-versus-host disease of the liver

We describe a series of cases of extreme hypercholesterolemia mediated by lipoprotein X in patients with chronic graft-versus-host disease of the liver after an allogeneic bone marrow transplant. All of the patients presented with a total cholesterol in excess of 1000 mg/dl (25.9 mmol/l). At the time they were also noted to have pseudohyponatremia. Cholesterol appeared to be predominantly carried by lipoprotein X. Intrahepatic cholestasis leading to reflux of bile lipoproteins into the bloodstream and subsequent formation of protein X appears to be the mechanism underlying this phenomenon. Complications, including retinal cholesterol thromboembolism and cholesteroloma of the lung have been seen in the patient with the highest cholesterol levels. Severe hypercholesterolemia is an important, and likely more common than previously reported, long-term complication of allogeneic hematopoietic stem cell transplantation. It is important for clinicians to familiarize themselves with the diagnostic and therapeutic challenges this condition presents.

A combination of serum low albumin and above-average cholesterol level was associated with excess mortality

BACKGROUND

There is no population-based prospective study concerning the relation between serum albumin and mortality in a non-Western population, and few previous studies included the subgroup analysis stratified by serum cholesterol level.

METHODS

A 13.7-year cohort study was conducted on 6,957 males and females aged 30-59 years from 300 randomly selected areas throughout Japan, who participated in the National Survey on Circulatory Disorders in 1980.

RESULTS

In the group with median and above of total cholesterol, one standard deviation (SD) increment of serum albumin (2.6 g/L for males and 2.4 g/L for females) was inversely associated with all-cause mortality for both males and females (relative risk RR = 0.68 and 0.81: 95% confidence interval CI = 0.53-0.87 and 0.68-0.98), and with cancer mortality for females (RR = 0.74; 95% Cl = 0.57-0.96);and the lowest category of serum albumin (< or = 43 g/L) showed the highest cardiovascular mortality for males (RR = 5.04; 95% CI = 1.04-24.5) among the three albumin categories. These relationships were not evident in the group with total cholesterol level below median.

CONCLUSION

A combination of a low albumin level and above average cholesterol level, even both within the clinical normal range,is associated with excess mortality in the Japanese general population.

Acute inflammation and infection maintain circulating phospholipid levels and enhance lipopolysaccharide binding to plasma lipoproteins

Circulating lipoproteins are thought to play an important role in the detoxification of lipopolysaccharide (LPS) by binding the bioactive lipid A portion of LPS to the lipoprotein surface. It has been assumed that hypocholesterolemia contributes to inflammation during critical illness by impairing LPS neutralization. We tested whether critical illness impaired LPS binding to lipoproteins and found, to the contrary, that LPS binding was enhanced and that LPS binding to the lipoprotein classes correlated with their phospholipid content. Whereas low serum cholesterol was almost entirely due to the loss of esterified cholesterol (a lipoprotein core component), phospholipids (the major lipoprotein surface lipid) were maintained at near normal levels and were increased in a hypertriglyceridemic subset of septic patients. The levels of phospholipids found in the LDL and VLDL fractions varied inversely with those in the HDL fraction, and LPS bound predominantly to lipoproteins in the LDL and VLDL fractions when HDL levels were low. Lipoproteins isolated from the serum of septic patients neutralized the bioactivity of the LPS that had bound to them. Our results show that the host response to acute inflammation and infection tends to maintain lipoprotein phospholipid levels and that, despite hypocholesterolemia and reduced HDL levels, circulating lipoproteins maintain their ability to bind and neutralize an important bacterial agonist, LPS.

Probucol prevents early coronary heart disease and death in the high-density lipoprotein receptor SR-BI/apolipoprotein E double knockout mouse

Mice with homozygous null mutations in the high-density lipoprotein receptor SR-BI (scavenger receptor class B, type I) and apolipoprotein E genes fed a low-fat diet exhibit a constellation of pathologies shared with human atherosclerotic coronary heart disease (CHD): hypercholesterolemia, occlusive coronary atherosclerosis, myocardial infarctions, cardiac dysfunction (heart enlargement, reduced systolic function and ejection fraction, and ECG abnormalities), and premature death (mean age 6 weeks). They also exhibit a block in RBC maturation and abnormally high plasma unesterified-to-total cholesterol ratio (0.8) with associated abnormal lipoprotein morphology (lamellar/vesicular and stacked discoidal particles reminiscent of those in lecithin/cholesterol acyltransferase deficiency and cholestasis). Treatment with the lipid-lowering, antiatherosclerosis, and antioxidation drug probucol extended life to as long as 60 weeks (mean 36 weeks), and at 5-6 weeks of age, virtually completely reversed the cardiac and most RBC pathologies and corrected the unesterified to total cholesterol ratio (0.3) and associated distinctive abnormal lipoprotein morphologies. Manipulation of the timing of administration and withdrawal of probucol could control the onset of death and suggested that critical pathological changes usually occurred in untreated double knockout mice between approximately 3 (weaning) and 5 weeks of age and that probucol delayed heart failure even after development of substantial CHD. The ability of probucol treatment to modulate pathophysiology in the double knockout mice enhances the potential of this murine system for analysis of the pathophysiology of CHD and preclinical testing of new approaches for the prevention and treatment of cardiovascular disease.

Vanishing bile duct syndrome associated with elevated pancreatic enzymes after short-term administration of amoxicillin

Amoxicillin is a widely used antibiotic, rarely being considered a cause of hepatic injury. We report the case of a 45-year-old woman who developed a vanishing bile duct syndrome 8 weeks after initiation of amoxicillin therapy. Liver biopsy showed destruction and loss of preformed bile ducts together with an inflammatory infiltrate involving eosinophilic leucocytes. Cholestasis was progressive despite prednisolone treatment and was accompanied by elevation of pancreatic enzymes. The patient died after 18 months from progressive liver failure. This case illustrates that amoxicillin alone can be a cause of progressive and ultimately fatal vanishing bile duct syndrome.

Basal and post-methionine serum homocysteine and lipoprotein abnormalities in patients with chronic liver disease

BACKGROUND

Lipoprotein abnormalities are commonly found in chronic liver diseases (CLDs), particularly hypercholesterolemia in primary biliary cirrhosis (PBC). However, affected patients may not be at increased risk of coronary heart disease. Cirrhotic patients display impaired methionine clearance, and an increased level of homocysteine, a methionine metabolite, is an independent risk factor for coronary heart disease. Thus, we hypothesized that the low risk of coronary heart disease in patients with CLD may be related to low serum levels of homocysteine. The aim of this study was to test this hypothesis after methionine load and to describe the serum lipoprotein profile in patients with PBC and in patients with hepatocellular liver disease.

METHODS

Fifteen female patients (mean age, 58.2 +/- 11.7 years) with PBC, 15 female patients (mean age, 54.5 +/- 9.6 years) with other causes of CLD, and 15 healthy sex- and age-matched controls were given L-methionine (50 mg/kg of ideal body weight). Basal fasting serum homocysteine level and 2, 4, and 6 hours of post-methionine load were determined using high-performance liquid chromatography with a fluorometric detector. Levels of fasting serum cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), lipoprotein (a) (Lp(a)), and apoprotein B were also determined.

RESULTS

Results showed that mean basal and post-methionine load (6 hours) serum homocysteine levels were statistically significantly higher in the patients with PBC and with CLD than in the control group (P=0.04) and that levels of serum cholesterol, LDL, HDL, and apoprotein B were significantly higher in the PBC patients than in the other two groups (P < or = 0.05). There was no correlation between any of these parameters and the severity of liver disease. Serum HDL was significantly lower in the CLD group (P < or = 0.05) and correlated with severity of liver disease. There was no significant difference in serum cholesterol, LDL, or apoprotein B between the CLD group and the controls. Serum triglyceride and Lp(a) levels were similar for all three groups.

CONCLUSIONS

In contrast to previous reports, the site of the methionine metabolic impairment was found to be below the homocysteine synthesis level. For most patients with CLD, factors other than serum homocysteine or Lp(a) are responsible for the reduction in the risk of coronary heart disease. Further studies with larger samples are needed.

The abnormal lipid spectrum in malignant obstructive jaundice in relation to endotoxin sensitivity and the result of preoperative biliary drainage

BACKGROUND

Biliary obstruction changes the spectrum of lipoproteins, which are now known to bind and neutralize endotoxin. Postoperative septic complications related to an increased susceptibility to endotoxin occur frequently in patients with obstructive jaundice. The effect of preoperative biliary drainage on changes in the lipoprotein spectrum and its relation to endotoxin sensitivity was studied.

METHODS

Abnormalities in the lipoprotein spectrum were assessed in 15 patients with malignant obstructive jaundice before and 3 weeks after endoscopic biliary drainage. Changes in endotoxin responsiveness were assessed by using endotoxin-neutralizing reagents (anti-CD14 monoclonal antibody, polymyxin B, and recombinant bactericidal permeability increasing protein) to block cytokine production in whole blood cell cultures that were stimulated by cholestatic plasma taken before and after drainage.

RESULTS

Drainage normalized very-low-density, low-density, and high-density lipoprotein cholesterol fractions from, respectively, 43% to 19%, 50% to 65%, and 6% to 16% (P <.01). Ex vivo stimulation of whole blood with predrainage cholestatic plasma was 20-fold higher (P <.001) than with postdrainage plasma. Blocking the endotoxin response during the stimulation with predrainage cholestatic plasma with anti-CD14 monoclonal antibody, polymyxin B or recombinant bactericidal permeability increasing protein resulted in attenuation of the inflammatory response, reducing tumor necrosis factor-alpha levels at least 5-fold.

CONCLUSIONS

Preoperative biliary drainage normalizes the changed lipid profile and the endotoxin-stimulating capacity of cholestatic plasma, and this signifies a change in sensitivity to endotoxin.

APA hamster model for diabetic atherosclerosis. 2. Analysis of lipids and lipoproteins

Syrian hamsters of the APA strain (APA hamsters) have recently been shown to have atheromatous lesions in the aortic arches under diabetic condition induced by a single injection of streptozotocin (SZ). In that model, fatty streaks, which are the initial lesions of atherogenesis, develop by 6 weeks after the injection (WAI). In this study, we evaluated plasma lipid concentrations and lipoprotein profiles in diabetic APA hamsters at 6 WAI to reveal the early stage of atherogenesis clinicopathologically. As a result, by biochemical analysis, hyperglycemic APA hamsters showed signs of hypercholesterolemia and hypertriglyceridemia. Low-density lipoprotein (LDL) cholesterol significantly increased, but high-density lipoprotein (HDL) cholesterol significantly decreased. Agarose gel electrophoresis showed an obvious increase in the fractions of chylomicron, LDL and abnormal lipoprotein. Plasma LDL in diabetic animals was in a state more susceptible to oxidization. In addition, a significant increase in glycated LDL was also found in the diabetic animals by enzyme linked immunosorbent assay (ELISA). Moreover, lipid peroxidation product (4-hydroxynonenal (4 HNE))-adducted proteins and advanced glycation end-products (AGE) were immunohistochemically detected in the foam cells of the fatty streaks. These results revealed that diabetic APA hamsters had hyperlipidemia characterized by increases in chylomicron, LDL and abnormal lipoprotein, and suggested that oxidized LDL and/or glycated LDL might be actively uptaken by macrophages and play an important role in the initial stage of atherogenesis.

Apolipoprotein E alleles in women with intrahepatic cholestasis of pregnancy

OBJECTIVE

To investigate the frequency of apolipoprotein E (apoE) alleles among women with intrahepatic cholestasis of pregnancy.

METHODS

The presence of the three most common apoE alleles (epsilon2, epsilon3, epsilon4) was determined by polymerase chain reaction-restriction fragment length polymorphism in two groups of women: healthy pregnant women (n = 47) and pregnant women with a diagnosis of intrahepatic cholestasis of pregnancy (n = 44). In addition, the frequencies of the alleles in the general population in our area are presented for comparison.

RESULTS

The frequency of the apo epsilon4 allele was 21.6% among women with intrahepatic cholestasis and it was 16.0% among healthy pregnant women (Fisher exact test; P= 0.216), which is close to the rate in the general population in our area (19%). None of the apoE genotypes was significantly over-represented, and homozygous genotype epsilon4 was not associated with more severe clinical disease than other genotypes.

CONCLUSION

The observed profiles of allele and genotype frequencies confirm the equilibrium state between apoE polymorphism and obstetric cholestasis and suggest that apoE does not play a major role in the development of intrahepatic cholestasis of pregnancy.

Lipoprotein-X in patients with cirrhosis: its relationship to cholestasis and hypercholesterolemia

Lipoprotein-X (Lp-X) is an abnormal low-density lipoprotein frequently found in liver disease. It is regarded as the most sensitive and specific biochemical parameter for the diagnosis of intra- and extrahepatic cholestasis. Moreover, Lp-X is supposed to contribute to the development of hypercholesterolemia in cholestatic liver disease, because it fails to inhibit de novo cholesterol synthesis. This investigation will focus on the relationship between the presence of Lp-X and serum lipid concentrations in cirrhosis. The significance of Lp-X in the diagnosis of cholestasis, compared with alkaline phosphatase (AP), gamma-glutamyl transferase (GGT), and bilirubin levels, will be assessed as well. The present cross-sectional study includes 212 patients with histopathologically proven cirrhosis. The detection of Lp-X and the quantification of -, beta-, and pre-beta-cholesterol was based on agar gel electrophoresis and polyanion precipitation. For the characterization of liver function, the concentrations of albumin and bilirubin, the activities of liver enzymes, and coagulation times were assessed. In a subgroup of 40 individuals, liver biopsies were re-evaluated to confirm or exclude intrahepatic cholestasis. As a result, there was no association between the appearance of Lp-X and total cholesterol concentrations. While all patients with Lp-X showed intrahepatic cholestasis (predictive value of the positive test = 1), only 16 of 28 patients with cholestasis formed Lp-X (sensitivity = 0.57). The activities of AP and of GGT, as well as the concentrations of bilirubin, were strongly elevated in most patients, with and without cholestasis. The predictive values of AP, GGT, and bilirubin were 0.77, 0.69, and 0.74 for the positive test and 0.5, 0, and 0.6 for the negative test, respectively. We conclude that Lp-X is not related to hypercholesterolemia in cirrhosis. The positive, but not the negative, Lp-X test has high predictive value for the diagnosis of cholestasis in cirrhosis. The biochemical parameters traditionally used for the assessment of extrahepatic cholestasis, AP, GGT, and bilirubin, do not support the diagnosis of intrahepatic cholestasis caused by cirrhosis.

Role of lipoprotein-X in foam cell formation and rat mesangial cell proliferation

1. In the present study, the effect of reconstituted lipoprotein-X (rLp-X) on lipid accumulation and foam cell formation in rat peritoneal macrophages was evaluated. Furthermore, the combined effect of rLp-X and macrophages on mesangial cell proliferation was examined. 2. Incubation of macrophages with rLp-X (177 and 387 nmol unesterified cholesterol (FC)/mL) resulted in an increase of cellular cholesterol (162%) and cholesteryl esters (223 to 245%) relative to control. 3. Oil Red O staining of macrophages treated with rLp-X revealed the presence of foam cells. 4. In conclusion, rLp-X had no effect on the proliferation of mesangial cells incubated in macrophage-conditioned medium.

Uptake and metabolism of lipoprotein-X in mesangial cells

Progressive glomerulosclerosis is a major complication in patients with familial lecithin:cholesterol acyltransferase (LCAT) deficiency. The lack of LCAT activity results in the accumulation of an abnormal lipoprotein, lipoprotein-X (Lp-X), in the plasma of these patients. Lipoprotein-X contains high levels of unesterified cholesterol and phosphatidylcholine. Lp-X may play a role in the accumulation of lipids in the kidney, which in turn may lead to glomerulosclerosis. The objective of this study is to examine the uptake and metabolism of Lp-X by rat mesangial cells. Our results suggest that Lp-X is taken up by mesangial cells and that the lipids in Lp-X are metabolized. Lysosomes containing unesterified cholesterol and phosphatidylcholine, in a molar ratio similar to Lp-X, were synthesized to investigate the roles individual apolipoproteins (apo CI, II, III and E) play in the uptake of Lp-X. Both apo CI and CIII inhibited its uptake while apo CII (1.5 fold) and E (4 fold) stimulated the uptake of Lp-X. Very low density lipoprotein (VLDL) and low density lipoprotein (LDL) inhibited Lp-X uptake by mesangial cells. However, at higher concentrations of high density lipoprotein (HDL), the uptake of Lp-X was stimulated. Proteoglycans have an important role in regulating the uptake of Lp-X, while cytoskeleton-dependent phagocytosis and the scavenger receptor do not appear to be involved.

Effect of lipoprotein-X on lipid metabolism in rat kidney

Lipoprotein-X (Lp-X) is found in the plasma of patients with familial lecithin: cholesterol acyltransferase (LCAT) deficiency syndromes. The majority of the patients with this disorder develop progressive glomerulosclerosis. In this study, the effect of Lp-X on lipid metabolism in perfused rat kidney was investigated. Lp-X was isolated from plasma of patients with familial LCAT deficiency by sequential ultracentrifugation and gel filtration column chromatography. Rat kidneys were perfused for 1-2 h with Krebs-Henseleit buffer containing 20 microM [1-(14)C]acetate or 20 microM [Me-3H]choline. In the presence of Lp-X, no significant difference in the incorporation of radioactivity into triglycerides, cholesterol, phosphocholine, CDP-choline and sphingomyelin was observed. However, incorporation of radioactivity into cholesteryl esters and phosphatidylcholine was significantly elevated in Lp-X perfused kidneys. The contents of cholesterol, cholesteryl esters and phosphatidylcholine were also significantly increased in Lp-X perfused kidneys. The increase in lipid content in the Lp-X perfused kidney is attributed to the direct deposition of Lp-X lipids into the organ. The increase in the labelling of cholesteryl esters was attributed to the increase of available substrate (cholesterol) for the acyl-CoA:cholesterol acyltransferase (ACAT) reaction. The increase in phosphatidylcholine labelling was caused by a reduced turnover of the newly synthesized labelled phosphatidylcholine during Lp-X perfusion.

Abnormalities of serum apo A1 containing lipoprotein particles in patients with primary biliary cirrhosis

Patients with primary biliary cirrhosis (PBC) do not appear to have an increased risk of cardiovascular disease despite elevations in serum cholesterol. Recent evidence has pointed to LpA1 (an apo A1 containing particle which contains apo A1 but not apo A2) in protecting against atherosclerosis. The aim of this study was to investigate apo Al containing particles in the serum of patients with PBC. Lipids and apolipoproteins were measured in 31 patients with PBC (30 females) and 27 control subjects (26 females). Patients were divided into 3 groups: group 1 with bilirubin < 18 micromol/l (n = 17); group 2 with bilirubin > 18 micromol/l (n = 11); and group 3 with end stage liver disease (ESLD, n = 3). As expected group 1 and 2 patients had higher total cholesterol, HDL cholesterol and phospholipids than control subjects. Apo B and apo A1 concentrations were similar to control subjects. However, LpA1 was greatly increased: 0.96 g/l (0.60-1.50), median (range) in group 1 and 1.09 g/l (0.75-1.33) in group 2 versus 0.62 g/l (0.45-0.93) for controls both P < 0.005 and the percentage of total apo A1 in the LpA1 fraction was increased: 54.8% (37.9-63.4) in group 1 and 55.7% (47.8-73.7) in group 2 versus 36.8% (25.1-49.1) for controls, both P < 0.005. Apo A2 concentration was reduced in group 1 0.38 g/l (0.30-0.51) and group 2 0.31 g/l (0.14-0.58) versus controls 0.43 g/l (0.36-0.57), P < 0.05 and P < 0.005 respectively. Patients with ESLD had reduced HDL cholesterol, apo A1, LpA1 and apo A2 compared to controls. These results suggest that PBC is associated with an altered distribution of apo A1 favouring an increased concentration of the protective LpA-I particles. Increased LpA1 concentration may be one of the factors contributing to the paradoxically low incidence of atherosclerosis in PBC patients.

Acute dyslipoproteinemia induced by interleukin-2: lecithin:cholesteryl acyltransferase, lipoprotein lipase, and hepatic lipase deficiencies

Recombinant human interleukin-2 (rIL-2) is used to treat refractory cancers. During such treatment, patients develop severe hypocholesterolemia along with striking alterations in the concentration and composition of the circulating lipoproteins. The present study was undertaken to gather information about the pathogenesis of these abnormalities. Patients were studied before-, during- and after a 5-day course of high dose i.v. rIL-2. Whole plasma cholesterol was markedly reduced by rIL-2 administration (52%; P < 0.001), whereas the triglyceride concentration did not change. Thus, the lipoproteins became triglyceride enriched (P = 0.004). Low density lipoprotein cholesterol, apolipoprotein B (apoB), high density lipoprotein cholesterol, and apoA-I concentrations all decreased. Esterified cholesterol levels were markedly reduced. Total plasma apoE increased markedly, and two kinds of abnormal particles appeared: 1) beta-migrating, very low density lipoproteins; and 2) discoidal, apoE- and phospholipid-containing particles with abnormal density and electrophoretic mobility. The activities of two lipoprotein triglyceride hydrolases, lipoprotein lipase and hepatic lipase, fell significantly during treatment and returned promptly to pretreatment levels after rIL-2 was discontinued. Lecithin:cholesteryl acyltransferase (LCAT) activity also decreased significantly (64%) during treatment, but in contrast to the lipases, remained low for at least 5 days after the last dose of rIL-2 (P < 0.001). High dose i.v. rIL-2 induces severe dyslipidemia with deficiencies of both postheparin lipases and acute LCAT deficiency. Most, if not all, of the lipoprotein changes observed are explained by the LCAT deficiency that follows IL-2-induced hepatocellular injury and cholestasis.

Cholesteryl ester transfer activity in liver disease and cholestasis, and its relation with fatty acid composition of lipoprotein lipids

Liver disease is accompanied by major qualitative and quantitative disturbances in plasma lipoprotein metabolism, the extent and intensity of which depend on the degree of parenchymal damage, cholestasis, or both. The main objective of this study was to determine the cholesteryl ester transfer CETP activity and its association with the lipoprotein neutral lipid composition in patients with either liver cirrhosis or cholestasis, as compared to normal controls. Lipoproteins were isolated by ultracentrifugation, lipids and apolipoproteins were measured by conventional methods, and the fatty acid composition was established by gas chromatography; CETP activity in lipoprotein-deficient plasma was measured by determining the transfer of [3H]cholesteryl esters from HDL to VLDL. Lipoprotein lipase and hepatic lipase activities were measured in post-heparin plasma by radiochemical methods. In patients with liver cirrhosis, low levels of VLDL, HDL, apo B, and Lp(a) were observed, as well as a change in the composition of HDL particles, with increases in the relative proportion of triglyceride and free cholesterol. Respectively, the last two changes could be attributed in part to the low hepatic lipase activity observed in this study, and to the low lecithin:cholesterol acyltransferase activity previously observed by others. In patients with cholestasis, a moderate hyperlipidemia due to the elevation of LDL was found. In contrast, HDL and apo A-I levels were very low reflecting a low number of HDL particles, which also had altered compositions with increases in the triglyceride and free cholesterol contents relative to apo A-I and esterified cholesterol, respectively. As regards the fatty acid composition of lipoprotein lipids, the two groups of patients showed, in general, a lower proportion of linoleic acid and a compensating higher proportion of oleic acid as compared to the controls, changes that were observed in both cholesteryl esters and triglycerides. In contrast, the proportions of oleic and palmitoleic acids in phospholipids were increased, whereas that of stearic acid was decreased in patients as compared to controls. In patients with liver cirrhosis, as well as in controls, no changes were observed in the fatty acid compositions of cholesteryl ester, triglycerides, or phospholipids among the different lipoproteins, which probably reflects the equilibration reached by the action of CETP. In patients with cholestasis, no differences were observed in fatty acid composition among the lipoprotein phospholipids but, interestingly, cholesteryl esters from VLDL had a significantly lower linoleic acid content than those from HDL, whereas triglycerides from VLDL had significantly higher oleic acid and lower linoleic acid contents than those from HDL. This distinct fatty acid composition of the neutral lipids between lipoproteins was associated with a significant decrease (25%) in the cholesteryl ester transfer activity in patients with cholestasis. We suggest that fat malabsorption due to the biliary defect may induce a decrease in cholesteryl ester transfer protein synthesis or section, which in turn would slow the equilibration of the neutral lipids among plasma lipoproteins.

Characterization of lipoproteins during human cholestasis

We have characterized changes in lipoproteins from cholestatic individuals and reproduced them by incubating lipoproteins from healthy individuals with cholic acid. The cholestatic patients showed an increase in low density lipoprotein (LDL) (>85%), with a smaller proportion of esterified cholesterol, and a fall in high density lipoprotein (HDL) (<10%), with a larger proportion of phospholipids. The protein composition of cholestatic HDL1 was characterized by a smaller proportion of apo A (I, II) and a prominent apo E fraction (39% vs. 9%). These changes involved an increase in degree of molecular packing (order) of HDL1. The addition of cholic acid to serum from healthy individuals altered the lipoprotein distribution, with an increase in LDL, the disappearance of HDL2 and HDL3 and the appearance of HDL1. These HDL1 were characterized by increased phospholipid and reduced apo AI fractions. They also showed a lower density and appeared as spherical particles in contrast to cholestatic HDL. Incubation of healthy HDL with cholic acid in vitro reproduces some of the alteration observed in cholestatic HDL.

Effect of ursodeoxycholic acid on serum lipids of patients with primary biliary cirrhosis

OBJECTIVE

To study the effects of ursodeoxycholic acid (UDCA) on lipid levels in patients with primary biliary cirrhosis (PBC).

DESIGN

A randomized, placebo-controlled prospective trial of UDCA was conducted in 177 well-characterized patients with PBC.

MATERIAL AND METHODS

The two treatment groups (placebo and UDCA) were matched at entry with respect to age, sex, histologic stage of PBC, biochemical values, and serum lipid levels. Serum cholesterol, high-density lipoprotein cholesterol, and triglyceride levels were measured at entry, 1 year, and 2 years.

RESULTS

The decrease in total cholesterol level at 1 and 2 years in the UDCA-treated group was significant in comparison with that in the placebo group. Serum high-density lipoprotein cholesterol and triglyceride levels, however, were unchanged. No severe side effects from UDCA were noted. The changes in serum cholesterol levels at 2 years were directly and strongly correlated with changes in serum bilirubin concentrations (r = 0.70; P < 0.001) and inversely correlated with initial serum cholesterol levels (r = -0.86; P < 0.00001).

CONCLUSION

The cholesterol-lowering effect of UDCA could be related to amelioration of the underlying liver disease or to a direct effect of the drug on the metabolism of cholesterol in patients with hypercholesterolemia.