MicroRNAs as Plasma Biomarkers of Hepatocellular Carcinoma in Patients with Liver Cirrhosis-A Cross-Sectional Study.

Ultrasound screening for hepatocellular carcinoma (HCC) in patients with liver cirrhosis has a poor sensitivity for small tumors. Circulating microRNAs (miRNAs) have been explored as HCC biomarkers, but results are diverging. Here, we evaluate if miRNAs up-regulated in HCC tissue can be detected in plasma and used as screening biomarkers for HCC. In this cross-sectional study, plasma, HCC tissue and surrounding non-tumorous liver tissue were collected from liver resections. Tissue miRNAs were identified and quantitated by RNA-sequencing analysis, and the fold-changes between HCC and surrounding liver tissue were calculated. The miRNAs up-regulated in HCCs were then re-analyzed in plasma from the same patients, and the miRNAs with the highest plasma levels were subsequently measured in plasma from an independent cohort of patients with cirrhosis or HCC. In tissues from 84 resected patients, RNA-sequencing detected 197 differentially expressed miRNAs, 40 of which had a raw count above 200 and were analyzed in plasma from the same cohort. Thirty-one miRNAs were selected for further analysis in 200 patients with HCC or cirrhosis. Of these, eleven miRNAs were significantly increased in HCC as compared to cirrhosis patients. Only miR-93-5p and miR-151a-3p were significantly associated with HCC, with an AUC of 0.662. In comparison, alpha-fetoprotein and des-gamma-carboxy prothrombin yielded an AUC of 0.816, which increased to 0.832 if miR-93-5p and miR-151a-3p were added. When including sex and age, the addition of miR-93-5p and miR-151a-3p did not further improve the AUC (from 0.910 to 0.911). In conclusion, micro-RNAs up-regulated in HCCs are detectable in plasma but have a poor performance as screening biomarkers of HCC.

A wide scan of plasma proteins demonstrates thioredoxin reductase 1 as a potential new diagnostic biomarker for hepatocellular carcinoma.

BACKGROUND: Patients with liver cirrhosis are recommended ultrasonography screening for early detection of hepatocellular carcinoma to increase the chances of curative treatment. However, ultrasonography alone lacks in sensitivity. Adding plasma biomarkers may increase the detection rate. We performed a broad exploratory analysis to find new plasma proteins with potential applicability for HCC screening in patients with cirrhosis. METHODS: In a protein discovery cohort of 172 patients with cirrhosis or HCC, we screened for 481 proteins with suspension bead array or proximity extension assay. From these, 24 proteins were selected for further analysis in a protein verification cohort (n = 160), using ELISA, Luminex or an electrochemiluminescence platform. A cut-off model and a stepwise logistic regression model were used to find combinations of proteins with the best discriminatory performance between HCC and cirrhosis. RESULTS: Stepwise logistic regression revealed alpha-fetoprotein (AFP), decarboxy-prothrombin (DCP), thioredoxin reductase 1 (TXNRD1), and fibroblast growth factor 21 (FGF21) as the proteins with the best discriminatory performance between HCC and cirrhosis. Adding TXNRD1 to DCP and AFP increased the AUC from 0.844 to 0.878, and combining AFP, DCP and TXNRD1 with age and sex resulted in an AUC of 0.920. FGF21, however, did not further increase the performance when including age and sex. CONCLUSION: In the present study, TXNRD1 improves the sensitivity and specificity of AFP and DCP as HCC screening tools in patients with cirrhosis. We suggest that TXNRD1 should be validated in prospective settings as a new complementary HCC biomarker together with AFP and DCP.

Case report: An unusual presentation of renal hypertension after damage control surgery.

INTRODUCTION AND IMPORTANCE: Hypertensive crisis may be a life-threatening condition to any patient and represents an even more serious condition in trauma patients following severe hemorrhage. CASE PRESENTATION: We present a case were surgical drape packing induced hypertensive crisis in a trauma patient, recently resuscitated from abdominal hemorrhage. CLINICAL DISCUSSION: We argue that direct compression of the kidney by the surgical drapes induced hypersecretion of renin with a mechanism equal to Page kidney. The hypertensive crisis as well as the hyperreninemia was resolved after removing the surgical drapes, and the patient's condition returned to normal without any sequelae. CONCLUSION: We encourage considering this unusual but important complication when packing of the abdomen has been carried out, and strongly recommend ruling out renin-mediated hypertension as a cause of post-operative hypertension in such cases.

Increased whole body energy expenditure and protection against diet-induced obesity in Cyp8b1-deficient mice is accompanied by altered adipose tissue features.

The aim of this study was to elucidate mechanisms whereby bile acids exert beneficial metabolic effects, using the Cyp8b1-/- mouse as model. These mice are unable to synthesize cholic acid, resulting in increased synthesis of chenodeoxycholic acid and enlarged bile acid pool. Cyp8b1-/- mice were found to be protected against high-fat diet induced obesity. Bomb calorimetry measurements showed increased faecal energy output in Cyp8b1-/ mice. Indirect calorimetry measurements demonstrated increased energy expenditure in Cyp8b1-/- mice. Meal tolerance tests revealed no differences in glucose disposal, but the insulin response was lower in Cyp8b1-/- mice. Intravenous glucose tolerance tests, as well as static incubations of isolated islets, showed no difference between the groups, whereas insulin tolerance tests demonstrated improved insulin sensitivity in Cyp8b1-/- mice. The genes encoding mitochondrial transcription factor A (TFAM) and type 2-iodothyronine deiodinase were upregulated in brown adipose tissue of Cyp8b1/- mice and Western blot analyses showed increased abundance of TFAM, and a trend towards increased abundance of UCP1. The upregulation of TFAM and UCP1 was accompanied by increased mitochondrial density, as shown by transmission electron microscopy. White adipocytes of Cyp8b1-/- mice exhibited increased responsiveness to both catecholamines and insulin in lipolysis experiments and increased insulin-stimulated lipogenesis. In conclusion, increased energy expenditure, mitochondrial density of brown adipocytes and faecal energy output may all contribute to the protection against diet-induced obesity of Cyp8b1-/- mice. Enhanced insulin sensitivity of Cyp8b1-/- mice is accompanied by increased hormonal responsiveness of white adipocytes.

Further evidence for a continuous flux of bile acids into the brain: trapping of bile acids in subdural hematomas.

Bile acids are known to pass the blood-brain barrier and are present at low concentrations in the brain. In a previous work, it was shown that subdural hematomas are enriched with bile acids and that the levels in such hematomas are higher than in the peripheral circulation. The mechanism behind this enrichment was never elucidated. Bile acids have a high affinity to albumin, and subdural hematomas contain almost as high albumin levels as the peripheral circulation. A subdural hematoma is encapsulated by fibrin which may allow passage of small molecules like bile acids. We hypothesized that bile acids originating from the circulation may be 'trapped' in the albumin in subdural hematomas. In the present work, we measured the conjugated and unconjugated primary bile acids cholic acid and chenodeoxycholic acid in subdural hematomas and in peripheral circulation of 24 patients. In most patients, the levels of both conjugated and free bile acids were higher in the hematomas than in the circulation, but the enrichment of unconjugated bile acids was markedly higher than that of conjugated bile acids. In patients with a known time interval between the primary bleeding and the operation, there was a correlation between this time period and the accumulation of bile acids. This relation was most obvious for unconjugated bile acids. The results are consistent with a continuous flux of bile acids, in particular unconjugated bile acids, across the blood-brain barrier. We discuss the possible physiological importance of bile acid accumulation in subdural hematomas.

Human apolipoprotein CIII levels; evaluation of three assay methods.

Apolipoprotein CIII (apoCIII) is associated with triglyceride (TG)-rich particles like VLDL and exerts an inhibitory effect of lipoprotein lipase. Increased levels are related to cardiovascular diseases and diabetes and therefore apoCIII has been proposed as a useful biomarker. Even if several commercial assays for measuring apoCIII in human plasma/serum are available, data is scarce concerning their reliability and none is used clinically. In the present study a comparative investigation has been done. Two ELISA-based methods (Cusabio Biotech and Assay Pro) and one nephelometric assay (Siemens Healthcare) were investigated. Serum and plasma samples were obtained from healthy volunteers and from samples sent to the Laboratory of Clinical Chemistry, preferably with higher levels of TGs. The Cusabio Biotech assay did not yield any valid results. However, both the methods from Assay Pro and Siemens Healthcare showed good performance with similar dynamic ranges. The latter assay had lower CV and required less work. In healthy individuals, apoCIII levels were not affected by fasting, freezing or thawing, nor did we find any gender differences. Individuals with elevated levels of TG displayed higher apoCIII values. Females with oral intake of contraceptives had higher levels. In conclusion, the nephelometric assay showed the best performance with the lowest CV, was less labor intensive than an assay based on ELISA and could therefore be suitable for clinical use.

Evaluation of a Novel Immunoassay for Quantification of C1q for Clinical Diagnostic Use.

Objectives: C1q is a valuable biomarker of disease activity in systemic lupus erythematosus (SLE). The "gold standard" assay, rocket immunoelectrophoresis (RIE), is time-consuming, and thus a shift to soluble immune precipitation techniques such as nephelometry has occurred. However, quantification of C1q with these techniques has been questioned as a result of the antibody binding properties of C1q. In the present work, we have compared results using various techniques (RIE, nephelometry, and ELISA) and have developed and validated a new magnetic bead-based sandwich immunoassay (MBSI). Methods: C1q was quantified by nephelometry and the new sandwich immunoassay in 45 serum samples analyzed using RIE. C1q was also assessed in plasma using RIE and sandwich immunoassay in samples from SLE patients with nephritis (n = 69), SLE patients without nephritis (n = 310) as classified by BILAG score, and matched controls (n = 322). In addition, cerebrospinal fluid (CSF) samples from 31 patients, previously analyzed with ELISA, were also analyzed with the MBSI to test the behavior of this new assay in the lower detection range. Results: We found a strong correlation between the new MBSI, RIE, and ELISA, but not with nephelometry. The MBSI demonstrated lower levels of C1q in SLE patients than in matched controls (p < 0.0001), and patients with nephritis had lower levels than patients without nephritis (p < 0.01). Similarily, RIE showed significant differences between the patient groups (p < 0.0001). An association was also found between the levels of C1q and the SLE disease activity index (SLEDAI). Furthermore, there was good correlation between the values obtained by MBSI and ELISA, in both serum (r = 0.960) and CSF (r = 0.786), underscoring the ability of both techniques to measure low concentrations of C1q with high accuracy. Conclusion: The sandwich immunoassay correlated well with RIE, but soluble immune precipitation techniques, such as nephelometry, did not appear suitable alternatives, since C1q itself, and possibly anti-C1q antibodies, interfered with the measurements. The new sandwich immunoassay is therefore a good replacement for RIE in monitoring SLE disease activity.

Hepcidin levels correlate to liver iron content, but not steatohepatitis, in non-alcoholic fatty liver disease.

BACKGROUND: One-third of patients with non-alcoholic fatty liver disease (NAFLD) develop dysmetabolic iron overload syndrome (DIOS), the pathogenesis of which is unknown. Altered production of the iron-regulatory peptide hepcidin has been reported in NAFLD, but it is unclear if this is related to iron accumulation, lipid status or steatohepatitis. METHODS: Eighty-four patients with liver disease, 54 of which had iron overload, underwent liver biopsy (n = 66) and/or magnetic resonance imaging (n = 35) for liver iron content determination. Thirty-eight of the patients had NAFLD, 29 had chronic liver disease other than NAFLD, and 17 had untreated genetic hemochromatosis. Serum hepcidin was measured with ELISA in all patients and in 34 controls. Hepcidin antimicrobial peptide (HAMP) mRNA in liver tissue was determined with real-time-quantitative PCR in 36 patients. RESULTS: Serum hepcidin was increased similarly in NAFLD with DIOS as in the other chronic liver diseases with iron overload, except for genetic hemochromatosis. HAMP mRNA in liver tissue, and serum hepcidin, both correlated to liver iron content in NAFLD patients (r2 = 0.45, p < 0.05 and r2 = 0.27, p < 0.05 respectively) but not to body mass index, NAFLD activity score or serum lipids. There was a good correlation between HAMP mRNA in liver tissue and serum hepcidin (r2 = 0.39, p < 0.01). CONCLUSIONS: In NAFLD with or without dysmetabolic iron overload, serum hepcidin and HAMP mRNA in liver correlate to body iron content but not to the degree of steatohepatitis or lipid status. Thus, the dysmetabolic iron overload syndrome seen in NAFLD is not caused by an altered hepcidin synthesis.

On the importance of albumin binding for the flux of 7α-hydroxy-3-oxo-4-cholestenoic acid in the brain.

We confirmed previous findings by a Japanese group that there is an accumulation of 7α-hydroxy-3-oxo-4-cholestenoic acid (7-Hoca) in human subdural hematomas. The accumulation correlated with the time from the bleeding to the sample collection. We present evidence that these accumulations are likely to be caused by the strong affinity of 7-Hoca to albumin and the marked difference between plasma and brain with respect to levels of albumin. In the circulation, 80-90% of 7-Hoca is bound to albumin with a ratio between the steroid acid and albumin of ∼1.4 ng/mg. In cerebrospinal fluid (CSF), the ratio between 7-Hoca and albumin is ∼30 ng/mg. When albumin or hemolyzed blood in a dialysis bag was exposed to CSF, there was a flux of 7-Hoca from CSF to the albumin. We suggest that the major explanation for accumulation of 7-Hoca in subdural hematoma is a flux from the brain into the hematoma due to the high affinity to albumin and the high capacity of 7-Hoca to pass biomembranes. We discuss the possibility that the markedly different ratios between 7-Hoca and albumin in circulation and brain can explain the flux of 7-Hoca from the brain into circulation against a concentration gradient.

Mice Abundant in Muricholic Bile Acids Show Resistance to Dietary Induced Steatosis, Weight Gain, and to Impaired Glucose Metabolism.

High endogenous production of, or treatment with muricholic bile acids, strongly reduces the absorption of cholesterol. Mice abundant in muricholic bile acids may therefore display an increased resistance against dietary induced weight gain, steatosis, and glucose intolerance due to an anticipated general reduction in lipid absorption. To test this hypothesis, mice deficient in steroid 12-alpha hydroxylase (Cyp8b1-/-) and therefore abundant in muricholic acids were monitored for 11 weeks while fed a high fat diet. Food intake and body and liver weights were determined, and lipids in liver, serum and feces were measured. Further, responses during oral glucose and intraperitoneal insulin tolerance tests were evaluated. On the high fat diet, Cyp8b1-/- mice displayed less weight gain compared to wildtype littermates (Cyp8b1+/+). In addition, liver enlargement with steatosis and increases in serum LDL-cholesterol were strongly attenuated in Cyp8b1-/- mice on high fat diet. Fecal excretion of cholesterol was increased and there was a strong trend for doubled fecal excretion of free fatty acids, while excretion of triglycerides was unaltered, indicating dampened lipid absorption. On high fat diet, Cyp8b1-/- mice also presented lower serum glucose levels in response to oral glucose gavage or to intraperitoneal insulin injection compared to Cyp8b1+/+. In conclusion, following exposure to a high fat diet, Cyp8b1-/- mice are more resistant against weight gain, steatosis, and to glucose intolerance than Cyp8b1+/+ mice. Reduced lipid absorption may in part explain these findings. Overall, the results suggest that muricholic bile acids may be beneficial against the metabolic syndrome.

Validation of a competitive ELISA assay for the quantification of human serum hepcidin.

BACKGROUND: Hepcidin-25 is a potential marker for iron disorders with a demand for accessible assays. This study aimed to evaluate a commercial competitive enzyme-linked immunosorbent assay (cELISA) for hepcidin quantitation. METHODS: Serum samples; 95 healthy subjects (HS), six patients with iron deficiency (ID), 84 patients with liver disorders (LD) and 220 hemodialysis patients (HD), were analyzed. Controls were used for imprecision, while accuracy was evaluated by quantitating hepcidin-25 with LC-MS/MS in 149 samples. Cross-reactivity for hepcidin-20 and hepcidin-22 was tested. Hepcidin-mRNA expression in 37 liver biopsies was measured. RESULTS: S-hepcidin ranged from 8-76 and 2-31 µg/L in healthy men and women. Levels in ID, LD and HD significantly differed from HS. Total coefficients of variation (CV) for controls were 24% and 22%. Within-sample CV was 10%. Despite a good correlation with LC-MS/MS (r = 0.89), the cELISA showed higher values and detected hepcidin-20 and hepcidin-22. Hepcidin-mRNA correlated well with S-hepcidin using cELISA and LC-MS/MS (r = 0.69 and 0.64). CONCLUSIONS: The correlation with LC-MS/MS is good and the examined kit can differentiate between patient groups although it is not specific for hepcidin-25. Considering ELISA's capacity to readily be set up, the investigated kit can be applied. Specific reference ranges are required.

Asymptomatic phosphomannose isomerase deficiency (MPI-CDG) initially mistaken for excessive alcohol consumption.

CASE REPORT: In a routine company health check-up, a 32-year-old woman presented a highly elevated serum level of carbohydrate-deficient transferrin (CDT), a biomarker for excessive alcohol consumption. The test result (~17% disialotransferrin, reference interval <2.0%; ~3% asialotransferrin, reference 0%) was confirmed by analysis of a second sample, while another alcohol biomarker, phosphatidylethanol (PEth) in whole-blood, was negative. This suggested that her elevated CDT may be unrelated to heavy drinking. The abnormal "type-1" transferrin glycoform pattern indicated a defect in N-glycan assembly occurring in congenital disorders of glycosylation (CDG), a family of rare inherited metabolic disorders. Probing for the underlying enzyme defect(s) using cultured skin fibroblasts demonstrated normal activity of phosphomannomutase, whereas the activity of phosphomannose isomerase (MPI) was reduced (0.64 mU/mg protein, reference 2.1-6.9), pointing to CDG of the MPI subtype (formerly called CDG-Ib). The diagnosis was confirmed by sequence analysis of the MPI gene revealing a homozygous missense mutation (c.656G>A) causing replacement of arginine by glutamine (p.R219Q). However, the woman had never experienced any clinical manifestations associated with MPI-CDG. Both parents, being distant relatives, were heterozygous mutation carriers with normal CDT values. Two of three siblings were not affected, whereas one brother was also homozygous for c.656G>A and had a highly elevated CDT and no clinical symptoms. CONCLUSION: The finding of MPI-CDG adults without clinical manifestations suggests that this type of the disorder may be underdiagnosed. If asymptomatic MPI-CDG subjects undergo CDT screening, their highly elevated test results may be wrongly interpreted as caused by excessive alcohol consumption.

LXR driven induction of HDL-cholesterol is independent of intestinal cholesterol absorption and ABCA1 protein expression.

We investigated whether: (1) liver X receptor (LXR)-driven induction of high-density lipoprotein cholesterol (HDL-C) and other LXR-mediated effects on cholesterol metabolism depend on intestinal cholesterol absorption; and (2) combined treatment with the LXR agonist GW3965 and the cholesterol absorption inhibitor ezetimibe results in synergistic effects on cholesterol metabolism that could be beneficial for treatment of atherosclerosis. Mice were fed 0.2 % cholesterol and treated with GW3965+ezetimibe, GW3965 or ezetimibe. GW3965+ezetimibe treatment elevated serum HDL-C and Apolipoprotein (Apo) AI, effectively reduced the intestinal cholesterol absorption and increased the excretion of faecal neutral sterols. No changes in intestinal ATP-binding cassette (ABC) A1 or ABCG5 protein expression were observed, despite increased mRNA expression, while hepatic ABCA1 was slightly reduced. The combined treatment caused a pronounced down-regulation of intestinal Niemann-Pick C1-like 1 (NPC1L1) and reduced hepatic and intestinal cholesterol levels. GW3965 did not affect the intestinal cholesterol absorption, but increased serum HDL-C and ApoAI levels. GW3965 also increased Apoa1 mRNA levels in primary mouse hepatocytes and HEPA1-6 cells. Ezetimibe reduced the intestinal cholesterol absorption, ABCA1 and ABCG5, but did not affect the serum HDL-C or ApoAI levels. Thus, the LXR-driven induction of HDL-C and ApoAI was independent of the intestinal cholesterol absorption and increased expression of intestinal or hepatic ABCA1 was not required. Inhibited influx of cholesterol via NPC1L1 and/or low levels of intracellular cholesterol prevented post-transcriptional expression of intestinal ABCA1 and ABCG5, despite increased mRNA levels. Combined LXR activation and blocked intestinal cholesterol absorption induced effective faecal elimination of cholesterol.

Bile acids trigger cholemic nephropathy in common bile-duct-ligated mice.

UNLABELLED: Tubular epithelial injury represents an underestimated but important cause of renal dysfunction in patients with cholestasis and advanced liver disease, but the underlying mechanisms are unclear. To address the hypothesis that accumulation and excessive alternative urinary elimination of potentially toxic bile acids (BAs) may contribute to kidney injury in cholestasis, we established a mouse model for detailed in vivo time course as well as treatment studies. Three-day common bile duct ligation (CBDL) induced renal tubular epithelial injury predominantly at the level of aquaporin 2-positive collecting ducts with tubular epithelial and basement membrane defects. This was followed by progressive interstitial nephritis and tubulointerstitial renal fibrosis in 3-, 6-, and 8-week CBDL mice. Farnesoid X receptor knockout mice (with a hydrophilic BA pool) were completely protected from CBDL-induced renal fibrosis. Prefeeding of hydrophilic norursodeoxycholic acid inhibited renal tubular epithelial injury in CBDL mice. In addition, we provide evidence for renal tubular injury in cholestatic patients with cholemic nephropathy. CONCLUSION: We characterized a novel in vivo model for cholemic nephropathy, which offers new perspectives to study the complex pathophysiology of this condition. Our findings suggest that urinary-excreted toxic BAs represent a pivotal trigger for renal tubular epithelial injury leading to cholemic nephropathy in CBDL mice.

Dolichol kinase deficiency (DOLK-CDG) with a purely neurological presentation caused by a novel mutation.

A 4-month old boy presented with multiple epileptic seizure types including West syndrome. Screening for infectious and structural etiologies showed normal results. A metabolic investigation was undertaken to investigate the cause of his neurological disease. Screening for congenital disorders of glycosylation (CDG) by HPLC analysis of serum carbohydrate-deficient transferrin (CDT) showed a type 1 pattern with 18% disialotransferrin (reference < 2%) and 2% asialotransferrin (reference 0). An undiagnosed 10-year old sister with a similar clinical history with infantile spasms at age 4 months, intellectual disability and an autism spectrum disorder, also showed a type 1 CDT pattern. Both siblings lacked dysmorphic features and extra-cerebral symptoms. The boy had cytotoxic edema of the thalamus and mesencephalon on MRI at age 7 months, whereas the girl had normal MRI at age 8 months. Phosphomannomutase (PMM) and phosphomannose isomerase (MPI) activities in cultured fibroblasts were normal, excluding PMM2-CDG and MPI-CDG. Fibroblast lipid-linked oligosaccharide analysis was also normal, suggesting an early defect in glycan assembly. Sequence analysis of the dolichol kinase gene revealed a homozygous new missense mutation (p.M1?; c.2 T > C) in both siblings. In conclusion, two siblings were demonstrated to suffer from DOLK-CDG (MIM 610768) and to be homozygous for a new mutation. They presented with West syndrome and so far show a purely neurological phenotype.

Further characterization of human glucocorticoid receptor mutants, R477H and G679S, associated with primary generalized glucocorticoid resistance.

OBJECTIVE: Primary generalized glucocorticoid resistance is a rare condition characterized by a generalized insensitivity to glucocorticoids, to some extent due to an impaired function of the glucocorticoid receptor. Our earlier genetic analysis of the human glucocorticoid receptor (hGR) in 12 unrelated patients with primary generalized glucocorticoid resistance revealed two new mutations, R477H in exon 4 and G679S in exon 8 in two patients. In order to further study the molecular mechanisms underlying the phenotype of these mutations we have investigated their effect on glucocorticoid signal transduction. METHODS: We have studied the DNA-binding ability of the R477H mutant with an electrophoretic mobility shift assay (EMSA). The ability of the R477H and the G679S mutants to affect TNFα induced NF-κB activity and wild-type GR signalling was studied in transient transfection assays. RESULTS: In EMSA the R477H mutation showed a reduced ability to bind to a glucocorticoid-response element compared to the wild-type GR. In transient transfection assays both the R477H mutant and the G679S mutant showed a dominant negative effect on co-transfected wild-type GR in Cos 7 cells. However, both mutants showed full capacity to repress TNFα-induced NF-κB activity. CONCLUSION: The impaired DNA-binding of the hGR, R477H mutant may explain the severe phenotype of cortisol resistance seen with this mutation. The dominant negative effects of both mutants on wild-type GR signalling probably contribute to the patients' cortisol resistance.

Identification of a functional apolipoprotein E promoter polymorphism regulating plasma apolipoprotein E concentration.

OBJECTIVE: There is compelling evidence that the plasma apolipoprotein E (APOE) concentration, in addition to the APOE ε2/ε3/ε4 genotype, influences plasma lipoprotein levels, but the functional genetic variants influencing the plasma APOE concentration have not been identified. APPROACH AND RESULTS: Genome-wide association studies in 2 cohorts of healthy, middle-aged subjects identified the APOE locus as the only genetic locus showing robust associations with the plasma APOE concentration. Fine-mapping of the APOE locus confirmed that the rs7412 ε2-allele is the primary genetic variant responsible for the relationship with plasma APOE concentration. Further mapping of the APOE locus uncovered that rs769446 (-427T/C) in the APOE promoter is independently associated with the plasma APOE concentration. Expression studies in 199 human liver samples demonstrated that the rs769446 C-allele is associated with increased APOE mRNA levels (P=0.015). Transient transfection studies and electrophoretic mobility shift assays in human hepatoma HepG2 cells corroborated the role of rs769446 in transcriptional regulation of APOE. However, no relationships were found between rs769446 genotype and plasma lipoprotein levels in 2 cohorts (n=1648 and n=1039) of healthy middle-aged carriers of the APOE ε3/ε3 genotype. CONCLUSIONS: rs769446 is a functional polymorphism involved in the regulation of the plasma APOE concentration.

Late cardiac tamponade by chylous pericardial effusion after coronary artery bypass surgery: case report.

Chylopericardium is an uncommon but serious complication after open heart surgery that often necessitates surgical treatment. We describe a case of continuous and severely symptomatic chylous pericardial effusion after coronary artery bypass grafting in which the diagnosis was established by lipid electrophoresis. Initial conservative management failed, and ligation of the thoracic duct and pericardial fenestration were finally required for a successful outcome.

Abolished synthesis of cholic acid reduces atherosclerotic development in apolipoprotein E knockout mice.

To investigate the effects of abolished cholic acid (CA) synthesis in the ApoE knockout model [apolipoprotein E (apoE) KO],a double-knockout (DKO) mouse model was created by crossbreeding Cyp8b1 knockout mice (Cyp8b1 KO), unable to synthesize the primary bile acid CA, with apoE KO mice. After 5 months of cholesterol feeding, the development of atherosclerotic plaques in the proximal aorta was 50% less in the DKO mice compared with the apoE KO mice. This effect was associated with reduced intestinal cholesterol absorption, decreased levels of apoB-containing lipoproteins in the plasma, enhanced bile acid synthesis, reduced hepatic cholesteryl esters, and decreased hepatic activity of ACAT2. The upregulation of Cyp7a1 in DKO mice seemed primarily caused by reduced expression of the intestinal peptide FGF15. Treatment of DKO mice with the farnesoid X receptor (FXR) agonist GW4064 did not alter the intestinal cholesterol absorption, suggesting that the action of CA in this process is confined mainly to formation of intraluminal micelles and less to its ability to activate the nuclear receptor FXR. Inhibition of CA synthesis may offer a therapeutic strategy for the treatment of hyperlipidemic conditions that lead to atherosclerosis.