Lipoprotein-X reduces LDL atherogenicity in primary biliary cirrhosis by preventing LDL oxidation

Association between primary biliary cholangitis with diabetes and cardiovascular diseases: A bidirectional multivariable Mendelian randomization study

BACKGROUND AND AIMS

Primary biliary cholangitis (PBC) is an autoimmune disease often accompanied by multisystem damage. This study aimed to explore the causal association between genetically predicted PBC and diabetes, as well as multiple cardiovascular diseases (CVDs).

METHODS

Genome-wide association studies (GWAS) summary data of PBC in 24,510 individuals of European ancestry from the European Association for the Study of the Liver was used to identify genetically predicted PBC. We conducted 2-sample single-variable Mendelian randomization (SVMR) and multivariable Mendelian randomization (MVMR) to estimate the impacts of PBC on diabetes (N = 17,685 to 318,014) and 20 CVDs from the genetic consortium (N = 171,875 to 1,030,836).

RESULTS

SVMR provided evidence that genetically predicted PBC is associated with an increased risk of type 1 diabetes (T1D), type 2 diabetes (T2D), myocardial infarction (MI), heart failure (HF), hypertension, atrial fibrillation (AF), stroke, ischemic stroke, and small-vessel ischemic stroke. Additionally, there was no evidence of a causal association between PBC and coronary atherosclerosis. In the MVMR analysis, PBC maintained independent effects on T1D, HF, MI, and small-vessel ischemic stroke in most models.

CONCLUSION

Our findings revealed the causal effects of PBC on diabetes and 7 CVDs, and no causal relationship was detected between PBC and coronary atherosclerosis.

Pruritus, Fatigue, Osteoporosis and Dyslipoproteinemia in Pbc Patients: A Clinician’s Perspective

In this review article, we summarize the most common clinical manifestations of Primary biliary cholangitis (PBC): pruritus, fatigue, osteoporosis, and dyslipoproteinemia and discuss their impact of the patients’ quality of life. More than half of PBC patients suffer from pruritus or fatigue at the time of diagnosis. We discuss the pathophysiological aspects of the PBC clinical manifestations and treatment options. The pathophysiology of pruritus and fatigue is not adequately elucidated, but IL-31 is associated with the severity of pruritus and could be used to objectify the subjective reporting by questionnaires. Although PBC patients suffer from atherogenic dyslipidemia, they do not seem to have a higher cardiovascular risk; however, this observation needs to be clarified by further clinical studies. The second-line of PBC treatment affects pruritus severity: Obeticholic acid (OCA) worsens pruritus while fibrates improve it. Itching can be alleviated by both non-pharmacological and pharmacological approach, however the are multiple barriers to pharmacological treatment. There is no adequate treatment for fatigue today. Treatment of osteoporosis and dyslipidemia is similar for non-PBC patients; stage of liver disease should be considered in treatment. Further research to clarify the pathophysiology and to eventually discover an effective treatment to improve survival and quality of life (especially pruritus and fatigue) in PBC patients is needed.

Dyslipidemia, Cholangitis and Fatty Liver Disease: The Close Underexplored Relationship: A Narrative Review

In assessing individual cardiovascular risk, dyslipidemia is known for emerging as a pivotal factor significantly contributing to major cardiovascular events. However, dyslipidemic patients frequently present with concurrent medical conditions, each with varying frequencies of occurrence; cholangitis, whether acute or chronic, and hepatic steatosis, along with associated conditions, are strongly associated with specific forms of dyslipidemia, and these associations are reasonably well elucidated. Conversely, evidence linking biliary disease to hepatic steatosis is comparatively scant. This narrative review aims to bridge this gap in knowledge concerning the interplay between dyslipidemia, cholangitis, and hepatic steatosis. By addressing this gap, clinicians can better identify patients at heightened risk of future major cardiovascular events, facilitating more targeted interventions and management strategies. The review delves into the intricate relationships between dyslipidemia and these hepatic and biliary clinical conditions, shedding light on potential mechanisms underlying their associations. Understanding these complex interactions is crucial for optimizing cardiovascular risk assessment as well and devising tailored treatment approaches for patients with dyslipidemia and associated hepatic disorders. Moreover, elucidating these connections empowers clinicians with the knowledge needed to navigate the multifaceted landscape of cardiovascular risk assessment and management effectively. By exploring the intricate relationships between dyslipidemia, cholangitis, and hepatic steatosis (without forgetting the possible clinical consequences of hepatic steatosis itself), this review not only contributes to the existing body of knowledge but also offers insights into potential avenues for further research and clinical practice. Thus, it serves as a valuable resource for healthcare professionals striving to enhance patient care and outcomes in the context of cardiovascular disease and associated hepatic conditions.

Use of therapeutic plasma exchange to remove lipoprotein X in a patient with vanishing bile duct syndrome presenting with cholestasis, pseudohyponatremia, and hypercholesterolemia: A case report and review of literature

INTRODUCTION

Lipoprotein X (Lp-X) is an abnormal lipoprotein found in multiple disease conditions, including liver dysfunction and cholestasis. High Lp-X concentrations can interfere with some laboratory testing that may result in spurious results. The detection of Lp-X can be challenging, and there is currently a lack of consensus regarding the management of Lp-X other than treating the underlying disease.

CASE PRESENTATION

A 42-year-old female with Hodgkin's lymphoma treated with dexamethasone, high dose cytarabine and cisplatin and vanishing bile duct syndrome confirmed by liver biopsy presented with cholestasis, pseudohyponatremia (sodium, 113 mmol/L; reference range 136-146 mmL/L; serum osmolality, 303 mOsm/kg), and hypercholesterolemia (> 2800 mg/dL, reference range < 200 mg/dL). Lp-X was confirmed by lipoprotein electrophoresis (EP). Although she did not manifest any specific signs or symptoms, therapeutic plasma exchange (TPE) was initiated based on laboratory findings of extreme hypercholesterolemia, spuriously abnormal serum sodium, and HDL values, and the potential for short- and long-term sequelae such as hyperviscosity syndrome, xanthoma, and neuropathy. During the hospitalization, she was treated with four 1.0 plasma volume TPE over 6 days using 5% albumin for replacement fluid. After the first TPE, total cholesterol (TC) decreased to 383 mg/dL and sodium was measured at 131 mmol/L. The patient was transitioned into outpatient maintenance TPE to eliminate the potential of Lp-X reappearance while the underlying disease was treated. Serial follow-up laboratory testing with lipoprotein EP showed the disappearance of Lp-X after nine TPEs over a 10-week period.

LITERATURE REVIEW

There are seven and four case reports of Lp-X treated with TPE and lipoprotein apheresis (LA), respectively. While all previous case reports showed a reduction in TC levels, none had monitored the disappearance of Lp-X after completing a course of therapeutic apheresis.

CONCLUSION

Clinicians should have a heightened suspicion for the presence of abnormal Lp-X in patients with cholestasis, hypercholesterolemia, and pseudohyponatremia. Once Lp-X is confirmed by lipoprotein EP, TPE should be initiated to reduce TC level and remove abnormal Lp-X. Most LA techniques are not expected to be beneficial since Lp-X lacks apolipoprotein B. Therefore, we suggest that inpatient course of TPE be performed every other day until serum sodium, TC and HDL levels become normalized. Outpatient maintenance TPE may also be considered to keep Lp-X levels low while the underlying disease is treated. Serum sodium, TC, and HDL levels should be monitored while on maintenance TPE.

Acute coronary syndrome after liver transplantation in a young primary biliary cholangitis recipient with dyslipidemia: a case report

Background

Primary biliary cholangitis (PBC) is a chronic, progressive liver disease associated with dyslipidemia. There is a consensus that PBC does not accelerate coronary artery disease despite high cholesterol levels, so the screening test for the coronary artery is not routinely performed before liver transplantation (LT). To date, no report has described the potential risk of PBC-related dyslipidemia for developing acute coronary syndrome (ACS) after LT.

Case presentation

A 40-year-old Asian female with a known history of PBC underwent ABO-incompatible living-donor LT, with her husband as the donor. Although she had high cholesterol and triglyceride levels that were refractory to medications, she passed all routine preoperative examinations, including cardiopulmonary function tests and infection screenings. One week after LT, she developed ACS with 90% stenosis of both the left anterior descending artery and left circumflex artery. Emergent stent implantation was successfully performed followed by dual antiplatelet therapy. The long history of PBC and associated severe dyslipidemia for 10 years would have accelerated the atherosclerosis, causing latent stenosis in the coronary artery. Inapparent stenosis might have become apparent due to unstable hemodynamics during the acute phase after LT.

Conclusions

PBC-related dyslipidemia potentially brings a risk for developing ACS after LT. This experience suggests that the preoperative evaluation of the coronary artery should be considered for high-risk patients, especially those who have drug-resistant dyslipidemia.

Features of Lipid Metabolism Disorders in Primary Biliary Cholangitis

Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, is an autoimmune liver disease that mostly affects women. A progressive disorder in the processes of bile secretion and enterohepatic bile salts circulation in patients with PBC already in its early stages, leading to an insufficient release of bile acids into the bowel and their entry into the systemic circulation. Insufficient bile acids released into the duodenum contributes to the development of malabsorption, energy malnutrition, and slowly progressive weight loss. The pathophysiological mechanisms of weight loss and its slow progression are associated with the deterioration of the fat emulsification processes and with the reduced absorption of hydrolyzed products, such as fatty acids and monoglycerides, with steatorrhea in patients with PBC, as well as in those with gut dysbiosis. Just in the early stages of the disease, this results in accelerated fatty acid β-oxidation that is aimed at compensating for progressive energy malnutrition. The entry of bile acids into the systemic circulation in PBC is accompanied by dyslipidemia. The mechanism of hyperlipidemia in patients with PBC differs from that in other conditions because along with an increase in total cholesterol (TC), there are elevated high-density lipoprotein levels and the appearance of unusual lipoprotein X (Lp-X). The appearance of Lp-X is most likely to be the body's protective reaction to inactivate the detergent effect of bile acids on the membrane structures of blood corpuscles and vascular endothelial cells. It is bile acids, rather than TC levels, that correlate with the content of Lp-X and determine its formation. Concomitant hypercholesterolemia in patients with PBC is also aimed at neutralizing the detergent effect of bile acids that have entered the systemic circulation and is most likely a compensatory reaction of the body. "Anomalous" hypercholesterolemia in PBC can serve as a model system for the search and development of new methods for the treatment of dyslipidemia since it occurs without an increase in the incidence of cardiovascular events.

Case report: Unusual and extremely severe lipoprotein X-mediated hypercholesterolemia in extrahepatic pediatric cholestasis

BACKGROUND

Lipoprotein X (LpX) - mediated extremely severe hyperlipidemia is a possible feature detectable in children with syndromic paucity of intralobular bile ducts (Alagille syndrome) but rarely in other types of intra- and/or extrahepatic infantile cholestasis.

CASE PRESENTATION

Here we report on a previously well 18-month child admitted for cholestatic jaundice and moderate hepatomegaly. Laboratory tests at entry showed conjugated hyperbilirubinemia, elevated values of serum aminotransferases, gamma-glutamyl transpeptidase (GGT) and bile acids (100 folds upper normal values). Extremely severe and ever-increasing hypercholesterolemia (total cholesterol up to 1,730 mg/dl) prompted an extensive search for causes of high GGT and/or hyperlipidemic cholestasis, including an extensive genetic liver panel (negative) and a liver biopsy showing a picture of obstructive cholangitis, biliary fibrosis, and bile duct proliferation with normal MDR3 protein expression. Results of a lipid study showed elevated values of unesterified cholesterol, phospholipids, and borderline/low apolipoprotein B, and low high-density lipoprotein-cholesterol. Chromatographic analysis of plasma lipoproteins fractions isolated by analytical ultracentrifugation revealed the presence of the anomalous lipoprotein (LpX). Magnetic resonance cholangiopancreatography and percutaneous transhepatic cholangiography showed stenosis of the confluence of the bile ducts with dilation of the intrahepatic biliary tract and failure to visualize the extrahepatic biliary tract. Surgery revealed focal fibroinflammatory stenosis of the left and right bile ducts confluence, treated with resection and bilioenteric anastomosis, followed by the rapid disappearance of LpX, paralleling the normalization of serum lipids, bilirubin, and bile acids, with a progressive reduction of hepatobiliary enzymes.

CONCLUSION

We have described a unique case of focal non-neoplastic extrahepatic biliary stenosis of uncertain etiology, presenting with unusual extremely high levels of LpX-mediated hypercholesterolemia, a condition which is frequently mistaken for LDL on routine clinical tests.

Gastric Xanthomatosis Secondary to Lipoprotein X in Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a rare autoimmune disease characterized by intralobular bile duct destruction. Patients typically present with generalized symptoms including fatigue and pruritis, and less commonly, manifestations of lipid deposition including xanthomas and xanthelasmas. We report a case of a 31-year-old female with PBC-associated cirrhosis who had cutaneous xanthelasmas and diffuse gastric xanthomas secondary to hyperlipidemia and lipoprotein X that completely resolved following liver transplantation. While gastric xanthomas have been reported in patients with PBC previously, to our knowledge, this is the first case report of diffuse gastric xanthomas secondary to PBC reported to resolve following liver transplantation, suggesting that liver transplantation is curative for gastric xanthomatosis in patients with PBC-related cirrhosis.

Statins Show Promise Against Progression of Liver Disease

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Autoimmune Rheumatic Diseases: An Update on the Role of Atherogenic Electronegative LDL and Potential Therapeutic Strategies

Atherosclerosis has been linked with an increased risk of atherosclerotic cardiovascular disease (ASCVD). Autoimmune rheumatic diseases (AIRDs) are associated with accelerated atherosclerosis and ASCVD. However, the mechanisms underlying the high ASCVD burden in patients with AIRDs cannot be explained only by conventional risk factors despite disease-specific factors and chronic inflammation. Nevertheless, the normal levels of plasma low-density lipoprotein (LDL) cholesterol observed in most patients with AIRDs do not exclude the possibility of increased LDL atherogenicity. By using anion-exchange chromatography, human LDL can be divided into five increasingly electronegative subfractions, L1 to L5, or into electropositive and electronegative counterparts, LDL (+) and LDL (-). Electronegative L5 and LDL (-) have similar chemical compositions and can induce adverse inflammatory reactions in vascular cells. Notably, the percentage of L5 or LDL (-) in total LDL is increased in normolipidemic patients with AIRDs. Electronegative L5 and LDL (-) are not recognized by the normal LDL receptor but instead signal through the lectin-like oxidized LDL receptor 1 (LOX-1) to activate inflammasomes involving interleukin 1β (IL-1β). Here, we describe the detailed mechanisms of AIRD-related ASCVD mediated by L5 or LDL (-) and discuss the potential targeting of LOX-1 or IL-1β signaling as new therapeutic modalities for these diseases.

Clinical laboratory characteristics of patients with obstructive jaundice accompanied by dyslipidemia

BACKGROUND

Abnormal lipid metabolism manifests as hypercholesterolemia in patients with obstructive jaundice due to lipoprotein X (LpX). Our aim was to explore the clinical laboratory characteristics of patients with obstructive jaundice accompanied by dyslipidemia in a large number of samples.

METHODS

A total of 665 patients with obstructive jaundice were included and categorized into two groups (with/without dyslipidemia) based on the ratio of the sum of HDL-c and LDL-c to total cholesterol [(HDL-c + LDL-c)/TC] with a cut-off value of 0.695. Laboratory liver, kidney, and blood lipid parameters were determined. Cholesterol composition assessment was performed by ultracentrifugation and high-performance liquid chromatography (UC-HPLC), and serum protein profiles were analyzed by capillary electrophoresis.

RESULTS

Liver function in patients with obstructive jaundice accompanied by dyslipidemia was more aggravated than that in patients with simple obstructive jaundice (P < 0.05). The (HDL-c + LDL-c)/TC ratio was negatively correlated with bilirubin levels (P < 0.05). In addition, the difference in ApoB/LDL-c ratios was statistically significant between the obstructive jaundice accompanied by dyslipidemia group and healthy control group (P < 0.05). The LDL-c concentration determined by the UC-HPLC method was more than five times that determined by the enzymatic method (P < 0.05). Bisalbuminemia was found in 43 of 60 patients with obstructive jaundice accompanied by hypercholesterolemia.

CONCLUSIONS

In patients with obstructive jaundice, the decreased (HDL-c + LDL-c)/TC ratio may be a novel marker to identify dyslipidemia secondary to LpX. The decreased ratio was associated with poor liver function and indicated disease progression.

Cholestatic Liver Diseases: A Primer for Generalists and Subspecialists

Cholestasis describes impairment in bile formation or flow which can manifest clinically with fatigue, pruritus, and jaundice. The differential diagnosis of cholestatic liver diseases is broad, and the etiologies of cholestasis vary in the anatomical location of the defect and acuity of presentation. Cholestasis may occur in a variety of clinical scenarios. Therefore, it is important for a diverse audience with varied clinical practices to have a basic understanding of manifestations of cholestatic liver diseases.

Patterns of serum lipids derangements and cardiovascular risk assessment in patients with primary biliary cholangitis

INTRODUCTION AND OBJECTIVES

Primary biliary cholangitis (PBC) is a chronic cholestatic autoimmune disease that disrupts the cholesterol metabolism. Our aim was to investigate the frequency of dyslipidemias and to evaluate the risk of cardiovascular events in a historic cohort of patients with PBC.

PATIENTS

All patients attended from 2000 to 2009 with histological diagnosis of PBC were included and were compared with healthy controls. The 10-year cardiovascular risk was estimated by the Framingham risk score.

RESULTS

Fifty four patients with PBC were included and compared to 106 controls. Differences in total cholesterol (263.8±123.9mg/dl vs. 199.6±40, p=0.0001), LDL-cholesterol (179.3±114.8 vs. 126.8±34.7, p=0.0001), HDL-cholesterol (62.4±36.2mg/dl vs. 47.3±12.3, p=0.0001) and triglycerides (149.1±59.1mg/dl vs. 126.4±55.4, p=0.001) were found. Hypercholesterolemia (>240mg/dl) was found in 52.4% of the patients with PBC vs. 11% in the control group, high LDL-cholesterol (160-189mg/dl) in 45.2% of the patients with PBC vs. 10% in controls and hyperalphalipoproteinemia (HDL-cholesterol >60mg/dl) in 45.2% of the patients with PBC vs. 16% in controls. The 10-year cardiovascular risk was 5.3%±5.9 in the patients with PBC and 4.1%±5.7 in the control group (p=0.723, IC 95%=0.637-1.104). Only one cardiovascular event (stroke) in a patient with PBC was registered in a mean follow up time of 57.9±36.5 months.

CONCLUSIONS

Marked derangements in serum lipids and a high frequency of dyslipidemias are found in patients with PBC, however, these do not increase the risk of cardiovascular events.

Primary biliary cholangitis presenting as acute ischemic stroke: A rare association

Primary biliary cholangitis is associated with hyperlipidemia, but studies show that the condition does not increase cardiovascular risks. The case presents acute ischemic stroke with no underlying risk factors and subsequent new diagnosis of primary biliary cholangitis, which can suggest possible association between primary biliary cholangitis and acute stroke.

Hyperlipidaemia in primary biliary cholangitis: treatment, safety and efficacy

Primary biliary cholangitis (PBC) is an autoimmune liver disease associated with altered lipoprotein metabolism, mainly cholesterol. Hypercholesterolaemia, a major modifiable risk factor for cardiovascular disease in the general population, occurs in 75%-95% of individuals with PBC. The impact of hypercholesterolaemia on cardiovascular risk in PBC, however, is controversial. Previous data have shown that hypercholesterolaemia in PBC is not always associated with an increase in cardiovascular events. However, patients with PBC with cardiovascular risk factors may still warrant cholesterol-lowering therapy. Treatment of hypercholesterolaemia in PBC poses unique challenges among primary care providers due to concerns of hepatotoxicity associated with cholesterol-lowering medications. This review summarises the current understanding of the pathophysiology of hypercholesterolaemia in PBC and its pertinent cardiovascular risk. We will also discuss indications for treatment and the efficacy and safety of available agents for hypercholesterolaemia in PBC.

Detection of Lipoprotein X (LpX): A challenge in patients with severe hypercholesterolaemia

Background

Lipoprotein X (LpX) is an abnormal lipoprotein fraction, which can be detected in patients with severe hypercholesterolaemia and cholestatic liver disease. LpX is composed largely of phospholipid and free cholesterol, with small amounts of triglyceride, cholesteryl ester and protein. There are no widely available methods for direct measurement of LpX in routine laboratory practice. We present the heterogeneity of clinical and laboratory manifestations of the presence of LpX, a phenomenon which hinders LpX detection.

Methods

The study was conducted on a 26-year-old female after liver transplantation (LTx) with severely elevated total cholesterol (TC) of 38 mmol/L and increased cholestatic liver enzymes. TC, free cholesterol (FC), cholesteryl esters (CE), triglycerides, phospholipids, HDL-C, LDL-C, and apolipoproteins AI and B were measured. TC/apoB and FC:CE ratios were calculated. Lipoprotein electrophoresis was performed using a commercially available kit and laboratory-prepared agarose gel.

Results

Commercially available electrophoresis failed to demonstrate the presence of LpX. Laboratory-prepared gel clearly revealed the presence of lipoproteins with γ mobility, characteristic of LpX. The TC/apoB ratio was elevated and the CE level was reduced, confirming the presence of LpX. Regular lipoprotein apheresis was applied as the method of choice in LpX disease and a bridge to reLTx due to chronic liver insufficiency.

Conclusions

The detection of LpX is crucial as it may influence the method of treatment. As routinely available biochemical laboratory tests do not always indicate the presence of LpX, in severe hypercholesterolaemia with cholestasis, any discrepancy between electrophoresis and biochemical tests should raise suspicions of LpX disease.

Patterns and prevalence of dyslipidemia in patients with different etiologies of chronic liver disease

Background

Liver disease impacts on hepatic synthesis of lipoproteins and lipogenesis but data on dyslipidemia during disease progression are limited. We assessed the patterns of dyslipidemia in (i) different liver disease etiologies and discriminated (ii) non-advanced (non-ACLD) from advanced chronic liver disease (ACLD) as it is unclear how progression to ACLD impacts on dyslipidemia-associated cardiovascular risk.

Methods

Patients with alcoholic liver disease (n = 121), hepatitis C (n = 1438), hepatitis B (n = 384), metabolic/fatty liver disease (n = 532), cholestatic liver disease (n = 119), and autoimmune hepatitis (n = 114) were included. Liver stiffness ≥15 kPa defined ACLD. Dyslipidemia was defined as total cholesterol >200 mg/dL, low-density lipoprotein (LDL)-cholesterol >130 mg/dL and triglycerides >200 mg/dL.

Results

Across all etiologies, total cholesterol levels were significantly lower in ACLD, when compared to non-ACLD. Accordingly, LDL-cholesterol levels were significantly lower in ACLD due to hepatitis C, hepatitis B, metabolic/fatty liver disease and autoimmune hepatitis. Triglyceride levels did not differ due to disease severity in any etiology. Despite lower total and LDL cholesterol levels in ACLD, etiology-specific dyslipidemia patterns remained similar to non-ACLD. Contrary to this “improved” lipid status in ACLD, cardiovascular comorbidities were more prevalent in ACLD: arterial hypertension was present in 26.6% of non-ACLD and in 55.4% of ACLD patients (p < 0.001), and diabetes was present in 8.1% of non-ACLD and 25.6% of ACLD patients (p < 0.001).

Conclusion

Liver disease etiology is a major determinant of dyslipidemia patterns and prevalence. Progression to ACLD “improves” serum lipid levels while arterial hypertension and diabetes mellitus are more prevalent. Future studies should evaluate cardiovascular events after ACLD-induced “improvement” of dyslipidemia.

Electronic supplementary material

The online version of this article (10.1007/s00508-019-01544-5) contains supplementary material, which is available to authorized users.

A National Hospital-Based Study of Hospitalized Patients With Primary Biliary Cholangitis

Epidemiological studies on primary biliary cholangitis (PBC) have been based primarily on tertiary referral case series. We aimed to estimate the incidence and prevalence and describe comorbidities in hospitalized patients with PBC in Italy using a national hospital-based data source. Data were extracted from the National Hospital Discharge Database, which includes all Italian individuals discharged from any hospital in the country. All adults diagnosed with biliary cirrhosis (International Classification of Diseases, Ninth Revision, Clinical Modification, 571.6) as the primary or secondary diagnosis from 2011 to 2015 were included. To determine whether a comorbidity was either more or less frequent in PBC patients compared with the general hospitalized Italian population, the standardized hospitalization ratio (SHR) was calculated. A total of 5,533 incident cases were identified from 2011 to 2015, 3,790 of whom were females (68.5%; female to male [F:M] ratio, 2.2:1). Prevalent cases were 9,664, of whom 7,209 were females (74.6%; F:M ratio, 2.9:1). The incident rate was 1.03 × 100,000 in males and 1.92 × 100,000 in females; prevalence was 1.89 × 100,000 in males and 4.75 × 100,000 in females. Extrahepatic autoimmune diseases, malignant neoplasms of liver and intrahepatic biliary ducts, and malignant neoplasms of gallbladder and extrahepatic bile ducts were found more frequently in PBC patients than in the general hospitalized population (SHR > 100), whereas cerebrovascular diseases and ischemic heart diseases were less frequent in PBC individuals (SHR < 100). Conclusion: This national study provides a survey of comorbidities associated with PBC. Hospitalized patients with PBC are more likely to have extrahepatic autoimmune diseases, hepatocellular carcinoma, and biliary tract cancers and a low risk of cardiovascular events.

Electronegative LDL from Rabbits Fed with Atherogenic Diet Is Highly Proinflammatory

Electronegative low-density lipoprotein (LDL(-)) has been found in the plasma of familial hypercholesterolemia and acute myocardial infarction and has been implicated in atherosclerosis and cardiovascular disease. However, less is known about the involvement of LDL(-) in atherosclerosis-related inflammation. This study aims at investigating the inducibility of LDL(-) by atherogenic diet in rabbits and at exploring the proinflammatory potential of the diet-induced LDL(-) in macrophages. Rabbits were fed with an atherogenic diet; LDL was isolated from plasma by NaBr density gradient ultracentrifugation and was then resolved into nLDL and LDL(-) by anion-exchange chromatography. Isolated nLDL and LDL(-) were directly used or incubated with 10 μM CuSO₄ for 24 h to produce copper- (Cu-) ox-nLDL and Cu-ox-LDL(-). The effects of these LDLs on inflammation were evaluated in THP-1-derived macrophages. Macrophages were treated with nLDL, LDL(-), and extensively oxidized LDL (ox-LDL), then the levels of interleukin- (IL-) 1β, IL-6, and tumor necrosis factor- (TNF-) α in a culture medium were determined by ELISA, and the levels of total and phosphorylated IκB, p65, p38, JNK, and ERK in cell lysates were determined by Western blotting. The LDL(-) induced significantly higher levels of IL-1β, IL-6, and TNF-α in the medium. The levels of phosphorylated/total IκB, p65, p38, JNK, and ERK were also upregulated by LDL(-). In contrast, nLDL, Cu-ox-nLDL, and Cu-ox-LDL(-) exhibited much less effect. Knockdown of lectin-type oxidized LDL receptor- (LOX-) 1 resulted in significant reduction in LDL(-)-induced IL-1β, IL-6, and TNF-α. In addition, these LDL(-) effects were also markedly attenuated by inhibition of NF-κB and ERK1/2. The data suggested that LDL(-) induced inflammation through LOX-1-, NF-κB-, and ERK1/2-dependent pathways. Taken together, our results show that rabbits fed with atherogenic diet produce a highly proinflammatory LDL(-) that is more potent in inducing inflammation than nLDL and extensively oxidize LDL in macrophages. The results thus provide a novel link between diet-induced hypercholesterolemia and inflammation.

Cholestasis-associated glucocorticoid overexposure does not increase atherogenesis

Chronic glucocorticoid overexposure predisposes to the development of atherosclerotic cardiovascular disease in humans. Cholestatic liver disease is associated with increased plasma glucocorticoid levels. Here, we determined - in a preclinical setting - whether the chronic presence of cholestatic liver disease also induces a concomitant negative impact on atherosclerosis susceptibility. Hereto, regular chow diet-fed atherosclerosis-susceptible hypercholesterolemic apolipoprotein E (APOE)-knockout mice were treated with the bile duct toxicant alpha-naphthylisothiocyanate (ANIT) for 8 weeks. ANIT exposure induced the development of fibrotic cholestatic liver disease as evident from collagen deposits and compensatory bile duct hyperproliferation within the liver and the rise in plasma levels of bilirubin (+60%; P < 0.01) and bile acids (10-fold higher; P < 0.01). Adrenal weights (+22%; P < 0.01) and plasma corticosterone levels (+72%; P < 0.01) were increased in ANIT-treated mice. In contrast, atherosclerosis susceptibility was not increased in response to ANIT feeding, despite the concomitant increase in plasma free cholesterol (+30%; P < 0.01) and cholesteryl ester (+42%; P < 0.001) levels. The ANIT-induced hypercorticosteronemia coincided with marked immunosuppression as judged from the 50% reduction (P < 0.001) in circulating lymphocyte numbers. However, hepatic glucocorticoid signaling was not enhanced after ANIT treatment. It thus appears that the immunosuppressive effect of glucocorticoids is uncoupled from their metabolic effect under cholestatic disease conditions. In conclusion, we have shown that cholestatic liver disease-associated endogenous glucocorticoid overexposure does not increase atherosclerosis susceptibility in APOE-knockout mice. Our studies provide novel preclinical evidence for the observations that the hypercholesterolemia seen in cholestatic human subjects does not translate into a higher risk for atherosclerotic cardiovascular disease.

The extrahepatic events of Asian patients with primary biliary cholangitis: A 30-year cohort study

The extrahepatic complications of primary biliary cholangitis (PBC) in Asian patients remain elusive. A 30-year cohort study of 150 Taiwanese PBC patients treated with ursodeoxycholic acid (UDCA) was conducted. Patients with alkaline phosphatase levels >1.67 × ULN after 1-year treatment were considered suboptimal responders. At baseline, of 150 patients (mean age: 53.75 years), 128 (85.3%) were females, and 34 (22.8%) had cirrhosis. The cumulative incidences of various incident events were all-cause mortality or liver transplantation: 46.7%; extrahepatic mortality: 24.5%; extrahepatic malignancies: 8.1%; hypertension: 46.2%; dyslipidemia: 44.1%; diabetes: 30.6%; hyperuricemia: 11.2%; acute coronary syndrome: 3.1%; cerebral vascular accident (CVA): 8.9%; autoimmune diseases: 16%; and osteoporosis: 20.9%. The 5- to 20-year cumulative incidences for all-cause mortality or liver transplantation and extrahepatic mortality were 16.2–41.3% and 3.1–11.9%, respectively. Baseline associations were age and alpha-fetoprotein levels with extrahepatic mortality, 80% due to sepsis; age with extrahepatic malignancies and hypertension; gender and hyperuricemia with CVA; and UDCA response with autoimmune disease. Conclusions: Sepsis accounted for most extrahepatic mortality in PBC patients, and the longer the follow-up was, the higher the extrahepatic/all-cause mortality ratio. Baseline age is crucial for incident extrahepatic events and only CVA shows gender-dimorphism; the association between UDCA response and autoimmune disease requires further investigation.

Controversy over the atherogenicity of lipoprotein-X

PURPOSE OF REVIEW

Lipoprotein-X (Lp-X) is an abnormal lipoprotein containing abundant free cholesterol and phospholipids, as well as some apolipoprotein E (apoE). Serum Lp-X increases in patients with cholestasis and lecithin-cholesterol acyltransferase deficiency, as well as in those receiving intravenous lipid emulsion. Lp-X is often associated with skin xanthomas in cholestatic patients. However, earlier studies showed that Lp-X is not taken up by murine macrophages, but exerts antiatherogenic actions. In this review, we discuss the heterogeneity of Lp-X and its potential atherogenicity.

RECENT FINDINGS

Mass spectrometry revealed that Lp-X of cholestatic patients is similar in lipid composition to low-density lipoprotein (LDL) and high-density lipoprotein, but not to bile acids, suggesting that Lp-X is synthesized in the liver. Palmar xanthomas appear in patients with cholestasis, but regress over months after improvement of hypercholesterolemia. Lp-X isolated from cholestatic patients is rich in apoE, and causes more lipid accumulation than oxidized LDL and acetyl LDL in human monocyte-derived macrophages.

SUMMARY

Lp-X is heterogeneous in apoE content. Lp-X is taken up in cholestatic patients by apoE-recognizing lipoprotein receptors. Further research is warranted to fully understand the atherogenicity of Lp-X and the clinical significance of elevated Lp-X concentrations, particularly in cholestatic patients.

Diagnosis and Management of Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic, cholestatic, autoimmune disease with a variable progressive course. PBC can cause debilitating symptoms including fatigue and pruritus and, if left untreated, is associated with a high risk of cirrhosis and related complications, liver failure, and death. Recent changes to the PBC landscape include a name change, updated guidelines for diagnosis and treatment as well as new treatment options that have recently become available. Practicing clinicians face many unanswered questions when managing PBC. To assist these healthcare providers in managing patients with PBC, the American College of Gastroenterology (ACG) Institute for Clinical Research & Education, in collaboration with the Chronic Liver Disease Foundation (CLDF), organized a panel of experts to evaluate and summarize the most current and relevant peer-reviewed literature regarding PBC. This, combined with the extensive experience and clinical expertise of this expert panel, led to the formation of this clinical guidance on the diagnosis and management of PBC.

Lipoprotein-X fifty years after its original discovery

AIMS

To review the formation, catabolism, and the possible atherogenic properties of Lp-X.

DATA SYNTHESIS

The conversion of cholesterol to bile acids is regulated by several mechanisms including cholesterol 7 alpha hydroxylase, fibroblast growth factor 19, and farnesoid X receptors. During cholestasis these mechanisms are altered and there is an accumulation of bile acids and cholesterol in plasma. The hypercholesterolemia observed in cholestasis is due to the presence of an anomalous lipoprotein called lipoprotein-X (Lp-X). Lp-X is a lipoprotein rich in phospholipid and free cholesterol present in plasma of patients with cholestasis and, with some variations, in patients with lecithin-cholesterol-acyl-transferase deficiency (LCAT), and after lipid infusion. Lp-X is formed from a bile lipoprotein moving to the blood vessels where it incorporates small quantities of triglycerides, apo-C and esterified cholesterol and becomes a "mature" Lp-X. The activity of the phosphatidilcholine canalicular transporter Mdr2 P-glycoprotein (homologous to the human ABCB4) is essential for LpX appearance, since its suppression abolishes Lp-X formation. However, the concentration of Lp-X in plasma is determined also by the degree of the cholestasis, the residual liver function, and the LCAT deficiency. The Lp-X catabolism seems to be mediated by the reticuloendothelial system and possibly the kidney.

CONCLUSIONS

Lp-X might be considered a defense mechanism against the toxic effect of free cholesterol in cholestasis. The frequency of cardiovascular events in patients affected by primary biliary cholangitis, in whom the Lp-X is present in high concentration, are not increased. Further studies could now clarify the remaining open questions on the role of Lp-X in the dyslipidemia of cholestasis.

Chronic Complications of Cholestasis: Evaluation and Management

Patients with primary biliary cholangitis (PBC) are at risk for various harmful consequences of chronic cholestasis. These include fat-soluble vitamin deficiency, even in the setting of macronutrient sufficiency, as well as metabolic bone disease, including osteoporosis with fractures. Hyperlipidemia is often present and less commonly associated with risk of cardiovascular event; however, the long-term effect of new emerging therapies for PBC remains to be determined. Patients with PBC also have infrequent but notable risk of portal hypertension despite early-stage disease. This review discusses the background, evaluation, and practical management of these complications of chronic cholestasis.

Risk of Cardiovascular Events in Patients with Primary Biliary Cholangitis - Systematic Review

Background and Aims: Hypercholesterolemia is a common finding in patients with primary biliary cholangitis (PBC) and is a well-defined risk factor for cardiovascular disease. However, studies have been mixed on whether PBC patients do, in fact, have higher cardiovascular risk. The aim of this study is to review the current literature and provide an evidence-based assessment of cardiovascular risk in PBC patients. Methods: We performed a systematic literature search on PubMed regarding patients with PBC and cardiovascular events from the database inception to July 1, 2017. A total of 33 articles fulfilling our inclusion criteria were found. Results: The majority of the studies evaluated yielded no statistically significant difference in cardiovascular disease in the PBC population compared to the general public. However, some reports found a statistically significantly increase in coronary artery disease. Several studies have looked at the specific lipid profile of patients with PBC with hypocholesteremia. While these lipid abnormalities differ by stage of disease, there is evidence to suggest that the specific lipid profile in PBC may have lower atherogenicity than in patients with hypercholesterolemia without PBC. Studies looking at patients with PBC with other risk factors for cardiovascular disease, such as hypertension and metabolic syndrome, have consistently found a higher risk for cardiovascular disease in these patients. Statin treatment is effective in reducing lipid levels and possibly improving endothelial inflammation in patients with PBC with hypercholesterolemia. Conclusions: There is not enough evidence to suggest an increased risk of cardiovascular disease in patients with PBC with hypercholesterolemia, except for those individuals with concomitant features of metabolic syndrome. In patients with PBC with no additional cardiovascular risk factors, individual risk/benefit discussion on lipid-lowering treatment should be considered.

Immune-mediated acquired lecithin-cholesterol acyltransferase deficiency: A case report and literature review

BACKGROUND

Recessive inherited disorder lecithin-cholesterol acyltransferase (LCAT) deficiency causes severe hypocholesterolemia and nephrotic syndrome. Characteristic lipoprotein subfractions have been observed in familial LCAT deficiency (FLD) with renal damage.

OBJECTIVE

We described a case of acquired LCAT deficiencies with literature review.

METHODS

The lipoprotein profiles examined by gel permeation-high-performance liquid chromatography (GP-HPLC) and native 2-dimensional electrophoresis before and after prednisolone (PSL) treatment.

RESULTS

Here we describe the case of a 67-year-old man with severely low levels of cholesterol. The serum LCAT activity was undetectable, and autoantibodies against it were detected. The patient developed nephrotic syndrome at the age of 70 years. Renal biopsy revealed not only membranous glomerulonephritis but also lesions similar to those seen in FLD. We initiated PSL treatment, which resulted in remission of the nephrotic syndrome. In GP-HPLC analysis, lipoprotein profile was similar to that of FLD although lipoprotein X level was low. Acquired LCAT deficiencies are extremely rare with only 7 known cases including ours. Patients with undetectable LCAT activity levels develop nephrotic syndrome that requires PSL treatment; cases whose LCAT activity levels can be determined may also develop nephrotic syndrome, but spontaneously recover.

CONCLUSION

Lipoprotein X may play a role in the development of renal impairment in individuals with FLD. However, the effect might be less significant in individuals with acquired LCAT deficiency.

Abnormalities of Lipoprotein Levels in Liver Cirrhosis: Clinical Relevance

Progressive lipoprotein impairment occurs in liver cirrhosis and is associated with increased morbidity and mortality. The present review aims to summarize the current evidence regarding the prognostic value of lipoprotein abnormalities in liver cirrhosis and to address the need of a better prognostic stratification of patients, including lipoprotein profile assessment. Low levels of lipoproteins are usual in cirrhosis. Much evidence supports the prognostic role of hypolipidemia in cirrhotic patients. In particular, hypocholesterolemia represents an independent predictor of survival in cirrhosis. In cirrhotic patients, lipoprotein impairment is associated with several complications: infections, malnutrition, adrenal function, and spur cell anemia. Alterations of liver function are associated with modifications of circulating lipids. Decreased levels of lipoproteins significantly impact the survival of cirrhotic patients and play an important role in the pathogenesis of some cirrhosis-related complications.

Electronegative L5-LDL induces the production of G-CSF and GM-CSF in human macrophages through LOX-1 involving NF-κB and ERK2 activation

BACKGROUND AND AIMS

Circulating levels of granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage colony-stimulating factor (GM-CSF) are associated with the severity of acute myocardial infarction (AMI). However, what causes increases in G-CSF and GM-CSF is unclear. In this study, we investigated whether L5-low-density lipoprotein (LDL), a mildly oxidized LDL from AMI, can induce G-CSF and GM-CSF production in human macrophages.

METHODS

L1-LDL and L5-LDL were isolated through anion-exchange chromatography from AMI plasma. Human macrophages derived from THP-1 and peripheral blood mononuclear cells were treated with L1-LDL, L5-LDL, or copper-oxidized LDL (Cu-oxLDL) and G-CSF and GM-CSF protein levels in the medium were determined. In addition, the effects of L5-LDL on G-CSF and GM-CSF production were tested in lectin-type oxidized LDL receptor-1 (LOX-1), CD36, extracellular signal-regulated kinase (ERK) 1, and ERK2 knockdown THP-1 macrophages.

RESULTS

L5-LDL but not L1-LDL or Cu-oxLDL significantly induced production of G-CSF and GM-CSF in macrophages. In vitro oxidation of L1-LDL and L5-LDL altered their ability to induce G-CSF and GM-CSF, suggesting that the degree of oxidation is critical for the effects. Knockdown and antibody neutralization experiments suggested that the effects were caused by LOX-1. In addition, nuclear factor (NF)-κB and ERK1/2 inhibition resulted in marked reductions of L5-LDL-induced G-CSF and GM-CSF production. Moreover, knockdown of ERK2, but not ERK1, hindered L5-LDL-induced G-CSF and GM-CSF production.

CONCLUSIONS

The results indicate that L5-LDL, a naturally occurring mild oxidized LDL, induced G-CSF and GM-CSF production in human macrophages through LOX-1, ERK2, and NF-κB dependent pathways.

Lipoprotein-X disease in the setting of severe cholestatic hepatobiliary autoimmune disease

Severe cholestatic disease and hyperlipidemia are both commonly encountered by medical professionals. This article reviews the current pathophysiological model of lipoprotein-X syndrome related to 3 cases from 2 academic medical centers in the United States.

Cholesterol metabolism in cholestatic liver disease and liver transplantation: From molecular mechanisms to clinical implications

The aim of this review is to enlighten the critical roles that the liver plays in cholesterol metabolism. Liver transplantation can serve as gene therapy or a source of gene transmission in certain conditions that affect cholesterol metabolism, such as low-density-lipoprotein (LDL) receptor gene mutations that are associated with familial hypercholesterolemia. On the other hand, cholestatic liver disease often alters cholesterol metabolism. Cholestasis can lead to formation of lipoprotein X (Lp-X), which is frequently mistaken for LDL on routine clinical tests. In contrast to LDL, Lp-X is non-atherogenic, and failure to differentiate between the two can interfere with cardiovascular risk assessment, potentially leading to prescription of futile lipid-lowering therapy. Statins do not effectively lower Lp-X levels, and cholestasis may lead to accumulation of toxic levels of statins. Moreover, severe cholestasis results in poor micellar formation, which reduces cholesterol absorption, potentially impairing the cholesterol-lowering effect of ezetimibe. Apolipoprotein B-100 measurement can help distinguish between atherogenic and non-atherogenic hypercholesterolemia. Furthermore, routine serum cholesterol measurements alone cannot reflect cholesterol absorption and synthesis. Measurements of serum non-cholesterol sterol biomarkers - such as cholesterol precursor sterols, plant sterols, and cholestanol - may help with the comprehensive assessment of cholesterol metabolism. An adequate cholesterol supply is essential for liver-regenerative capacity. Low preoperative and perioperative serum cholesterol levels seem to predict mortality in liver cirrhosis and after liver transplantation. Thus, accurate lipid profile evaluation is highly important in liver disease and after liver transplantation.

Severe hypercholesterolemia mediated by lipoprotein X in a patient with cholestasis

Lipoprotein X (LpX) is an abnormal lipoprotein associated with cholestasis. It is a significant cause of severe hypercholesterolemia and should always be considered in patients with cholestatic liver disease. This case highlights the significance of LpX as a cause of severe hypercholesterolemia in a patient with cholestasis secondary to a granulomatous hepatitis attributed to tuberculosis. Lipoprotein agarose gel electrophoresis and gradient gel electrophoresis were performed for the detection of LpX. The liver function tests, electrolytes, lipid profile and bile acids were also determined. Anti-tuberculous therapy was initiated and the liver functions improved with normalisation of the lipid profile.

Severe hypercholesterolemia and liver disease in a 3-year old

Lipoprotein-X, which is composed of phospholipids and non-esterified cholesterol, is an abnormal lipoprotein with a density range similar to LDL-C. The two most common ways which lipoprotein-X accumulates is from reflux of bile salts into plasma or deficiency in lecithin cholesterol acyltransferase. This is a case of severe hypercholesterolemia and liver disease in a 3- year old male that presented with pruritus, pale stool, scleral ictus, and abdominal distention. He was diagnosed with primary sclerosing cholangitis which was confirmed by liver biopsy. Our patient was treated with steroids and immunomodulator therapy which was associated with significant reduction in cholestasis and LDL-C levels. Lipoprotein-X has several properties that make it anti-atherogenic, which raises the question if treatment for hypercholesterolemia should be initiated.

Risk of cerebrovascular accident in patients with primary biliary cirrhosis: a systematic review and meta-analysis

OBJECTIVE

Dyslipidemia is common among patients with primary biliary cirrhosis (PBC) and might increase the risk of cerebrovascular accident (CVA). However, data from epidemiologic studies remain inconclusive. This study aims to further investigate this association.

MATERIALS AND METHODS

We carried out a systematic review and meta-analysis of observational studies that compared the risk of CVA in patients with PBC versus controls. Pooled risk ratios and 95% confidence intervals were combined using a random-effect, generic inverse variance method of DerSimonian and Laird.

RESULTS

Four studies with 2309 patients with PBC were identified and included in our data analysis. The pooled risk ratio of CVA in patients with PBC was 1.11 (95% confidence interval, 0.81-1.51). The statistical heterogeneity was insignificant, with an I of 14%.

CONCLUSION

A significantly increased risk of CVA among patients with PBC was not observed in this study.

Coronary artery disease in primary biliary cirrhosis: A systematic review and meta-analysis of observational studies

AIM

To investigate the association between primary biliary cirrhosis (PBC) and risk of coronary artery disease (CAD).

METHODS

We conducted a systematic review and meta-analysis of published observational studies that reported relative risks, odd ratios, hazard ratios or standardized incidence ratios with 95% confidence intervals (CI) comparing CAD risk in patients with PBC versus non-PBC controls. Pooled risk ratios and 95% confidence intervals were combined using a random-effect model and generic inverse variance of DerSimonian and Laird methods.

RESULT

Four studies with 3362 patients with PBC were identified and included in our data analysis. The pooled risk ratio of CAD in patients with PBC was 1.57 (95% CI, 1.21-2.06). The statistical heterogeneity was low with an I(2) of 38%.

CONCLUSION

Our study demonstrated a statistically significant increased risk of CAD among patients with PBC.

Management of lipoprotein X and its complications in a patient with primary sclerosing cholangitis

Lipoprotein X (LpX) is an abnormal lipoprotein found in conditions such as lecithin:cholesterol acyltransferase deficiency and cholestatic states (e.g., primary biliary cirrhosis and primary sclerosing cholangitis). Management of severe hypercholesterolemia due to LpX with drugs and physical removal methods is not well established in the literature. A case is discussed of a 51-year-old woman who presented with multiple electrolyte abnormalities, xanthomas and neuropathy found to be secondary to LpX in the setting of primary sclerosing cholangitis. This case highlights that oral medications, including statins, may be insufficient to normalize lipid levels or improve clinical symptoms of LpX and presents therapeutic plasma exchange as a safe and effective therapeutic option to treat the morbid sequela of LpX hyperlipidemia.

Differences in long-term survival among liver transplant recipients and the general population: a population-based Nordic study

Dramatic improvement in first-year outcomes post-liver transplantation (LT) has shifted attention to long-term survival, where efforts are now needed to achieve improvement. Understanding the causes of premature death is a prerequisite for improving long-term outcome. Overall and cause-specific mortality of 3,299 Nordic LT patients (1985-2009) having survived 1 year post-LT were divided by expected rates in the general population, adjusted for age, sex, calendar date, and country to yield standardized mortality ratios (SMRs). Data came from the Nordic Liver-Transplant Registry and WHO mortality-indicator database. Stagnant patient survival rates >1 year post-LT were 21% lower at 10 years than expected survival for the general population. Overall SMR for death before age 75 (premature mortality) was 5.8 (95% confidence interval [CI] 5.4-6.3), with improvement from 1985-1999 to 2000-2010 in hepatitis C (HCV) (SMR change 23.1-9.2), hepatocellular carcinoma (HCC) (SMR 38.4-18.8), and primary sclerosing cholangitis (SMR 11.0-4.2), and deterioration in alcoholic liver disease (8.3-24.0) and acute liver failure (ALF) (5.9-7.6). SMRs for cancer and liver disease (recurrent or transplant-unrelated disease) were elevated in all indications except primary biliary cirrhosis (PBC). Absolute mortality rates underestimated the elevated premature mortality from infections (SMR 22-693) and kidney disease (SMR 13-45) across all indications, and from suicide in HCV and ALF. SMR for cardiovascular disease was significant only in PBC and alcoholic liver disease, owing to high mortality in the general population. Transplant-specific events caused 16% of deaths.

CONCLUSION

standardized premature mortality provided an improved picture of long-term post-LT outcome, showing improvement over time in some indications, not revealed by overall absolute mortality rates. Causes with high premature mortality (infections, cancer, kidney and liver disease, and suicide) merit increased attention in clinical patient follow-up and future research.

A vaccine targeted at CETP alleviates high fat and high cholesterol diet-induced atherosclerosis and non-alcoholic steatohepatitis in rabbit

Low HDL-C levels are associated with atherosclerosis and non-alcoholic steatohepatitis, and increased levels may reduce the risk of these diseases. Inhibition of cholesteryl ester transfer protein (CETP) activity is considered a promising strategy for increasing HDL-C levels. Since CETP is a self-antigen with low immunogenicity, we developed a novel CETP vaccine (Fc-CETP₆) to overcome the low immunogenicity of CETP and for long-term inhibition of CETP activity. The vaccine consists of a rabbit IgG Fc domain for antigen delivery to antigen-presenting cells fused to a linear array of 6 repeats of a CETP epitope to efficiently activate B cells. Rabbits were fed a high fat/cholesterol (HFC) diet to induce atherosclerosis and NASH, and immunized with Fc-CETP₆ vaccine. The Fc-CETP₆ vaccine successfully elicited anti-CETP antibodies and lowered plasma CETP activity. The levels of plasma HDL-C and ApoA-I were higher, and plasma ox-LDL lower, in the Fc-CETP₆-immunized rabbits as compared to the unimmunized HFC diet-fed rabbits. Pathological analyses revealed less lipid accumulation and inflammation in the aorta and liver of the Fc-CETP₆-immunized rabbits. These results show that the Fc-CETP₆ vaccine efficiently elicited antibodies against CETP and reduced susceptibility to both atherosclerosis and steatohepatitis induced by the HFC diet. Our findings suggest that the Fc-CETP₆ vaccine may improve atherosclerosis and NASH and has high potential for clinical use.

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.

Revising the high-density lipoprotein targeting strategies - insights from human and preclinical studies

In recent years, the high-density lipoprotein (HDL) hypothesis has been challenged. Several completed randomized clinical trials continue to fall short in demonstrating HDL, or at least HDL-cholesterol (HDL-C) levels, as being a consistent target in the prevention of cardiovascular diseases. However, population studies and findings in lipid modifying trials continue to strongly support HDL-C as a superb risk predictor. It is increasingly evident that the complexity of HDL metabolism confounds the use of HDL-C concentration as a unified target. However, important insights continue to emerge from the post hoc analyses of recently completed (i) fibrate-based FIELD and ACCORD trials, including the unexpected beneficial effect of fibrates in microvascular diseases, (ii) the niacin-based AIM-HIGH and HPS2-THRIVE studies, (iii) recombinant HDL-based as well as (iv) the completed CETP inhibitor-based trials. These together with on-going mechanistic studies on novel pathways, which include the unique roles of microRNAs, post-translational remodeling of HDL and novel pathways related to HDL modulators will provide valuable insights to guide how best to refocus and redesign the conceptual framework for selecting HDL-based targets.

Malondialdehyde mediates oxidized LDL-induced coronary toxicity through the Akt-FGF2 pathway via DNA methylation

Background

Oxidized LDL (oxLDL) is involved in the development of atherosclerotic heart disease through a mechanism that is not fully understood. In this study, we examined the role of malondialdehyde (MDA), an important oxidative stress epitope of oxLDL, in mediating coronary endothelial cytotoxicity.

Results

Human coronary artery endothelial cells (HCAECs) were treated with oxLDL in the presence or absence of antibody against MDA (anti-MDA) or apoB100 (anti-apoB100). In HCAECs treated with oxLDL (100 μg/ml) alone, DNA synthesis, cell viability, and expression of prosurvival fibroblast growth factor 2 (FGF2) were significantly reduced (P < 0.01 vs phosphate buffered saline–treated cells). These inhibitory effects of oxLDL were significantly attenuated in HCAECs cotreated with anti-MDA (0.15 μg/ml; P < 0.05 vs oxLDL-treated cells), but not in those cotreated with anti-apoB100. When we tested the effects of a panel of signal transduction modifiers on the signal transduction pathways of MDA in oxLDL-treated HCAECs, we found that MDA-induced cytotoxicity was mediated partly through the Akt pathway. Using a reporter gene assay, we identified an oxLDL-response element in the FGF2 promoter that was responsible for the transcriptional repression of FGF2 by oxLDL. The results of bisulfite genomic DNA sequencing showed that in HCAECs treated with oxLDL, the GC-rich promoter of FGF2 was heavily methylated at cytosine residues, whereas cotreatment with anti-MDA markedly reduced oxLDL-induced FGF2 promoter methylation.

Conclusion

OxLDL disrupts the growth and survival of HCAECs through an MDA-dependent pathway involving methylation of the FGF2 promoter and repression of FGF2 transcription. This novel epigenetic mechanism of oxLDL may underlie its atherogenicity in patients with atherosclerotic cardiovascular disease.

Cardiovascular risk, lipidemic phenotype and steatosis. A comparative analysis of cirrhotic and non-cirrhotic liver disease due to varying etiology

BACKGROUND

Liver regulates lipid metabolism in health and disease states. Nevertheless, the entity of cardiovascular risk (CVR) resulting from dysregulation of lipid metabolism secondary to liver disease is poorly characterized.

AIM AND METHODS

To review, based on a PubMed literature search, the features and the determinants of serum lipid phenotype and its correlation with hepatic steatosis, insulin resistance (IR) and CVR across the wide spectrum of the most common chronic liver diseases due to different etiologies.

RESULTS

Alcoholic liver disease (ALD) is associated with steatosis, IR and a typical lipid profile. The relationship between alcohol intake, incident type 2 diabetes (T2D) and CVR describes a J-shaped curve. Non-alcoholic fatty liver disease (NAFLD), and probably nonalcoholic steatohepatitis (NASH) in particular, is associated with IR, atherogenic dyslipidemia and increased CVR independent of traditional risk factors. Moreover, NASH-cirrhosis and T2D contribute to increasing CVR in liver transplant recipients. HBV infection is generally free from IR, steatosis and CVR. HCV-associated dysmetabolic syndrome, featuring steatosis, hypocholesterolemia and IR, appears to be associated with substantially increased CVR. Hyperlipidemia is an almost universal finding in primary biliary cirrhosis, a condition typically spared from steatosis and associated with neither subclinical atherosclerosis nor excess CVR. Finally, little is known on CVR in patients with hepatocellular carcinoma.

CONCLUSIONS

CVR is increased in ALD, NAFLD and chronic HCV infection, all conditions featuring IR and steatosis. Therefore, irrespective of serum lipid phenotype, hepatic steatosis and IR may be major shared determinants in amplifying CVR in common liver disease due to varying etiology.