Apolipoprotein(a) Kinetics in Statin-Treated Patients With Elevated Plasma Lipoprotein(a) Concentration.

BACKGROUND: Lipoprotein(a) [Lp(a)] is a low-density lipoprotein‒like particle containing apolipoprotein(a) [apo(a)]. Patients with elevated Lp(a), even when treated with statins, are at increased risk of cardiovascular disease. We investigated the kinetic basis for elevated Lp(a) in these patients. OBJECTIVES: Apo(a) production rate (PR) and fractional catabolic rate (FCR) were compared between statin-treated patients with and without elevated Lp(a). METHODS: The kinetics of apo(a) were investigated in 14 patients with elevated Lp(a) and 15 patients with normal Lp(a) levels matched for age, sex, and body mass index using stable isotope techniques and compartmental modeling. All 29 patients were on background statin treatment. Plasma apo(a) concentration was measured using liquid chromatography-mass spectrometry. RESULTS: The plasma concentration and PR of apo(a) were significantly higher in patients with elevated Lp(a) than in patients with normal Lp(a) concentration (all P < 0.01). The FCR of apo(a) was not significantly different between the groups. In univariate analysis, plasma concentration of apo(a) was significantly associated with apo(a) PR in both patient groups (r = 0.699 and r = 0.949, respectively; all P < 0.01). There was no significant association between plasma apo(a) concentration and FCR in either of the groups (r = 0.160 and r = -0.137, respectively). CONCLUSION: Elevated plasma Lp(a) concentration is a consequence of increased hepatic production of Lp(a) particles in these patients. Our findings provide a kinetic rationale for the use of therapies that target the synthesis of apo(a) and production of Lp(a) particles in patients with elevated Lp(a).

Fractional turnover of apolipoprotein(a) and apolipoprotein B-100 within plasma lipoprotein(a) particles in statin-treated patients with elevated and normal Lp(a) concentration.

CONTEXT: Lipoprotein(a) [Lp(a)] is a highly atherogenic lipoprotein characterized by apolipoprotein(a) [apo(a)] covalently bounded to apoB-100 (apoB). However, the metabolism of apo(a) and apoB within plasma Lp(a) particles in patients on statins remains unclear. METHODS: The kinetics of Lp(a)-apo(a) and Lp(a)-apoB were determined in 20 patients with elevated Lp(a) (≥0.8 g/L; n = 10) and normal Lp(a) (≤0.3 g/L; n = 10) using stable isotope techniques and compartmental modeling. Plasma apo(a) concentration was measured using liquid chromatography-mass spectrometry. All patients were on statin therapy and were studied in the fasting state. RESULTS: The fractional catabolic rate (FCR) of Lp(a)-apo(a) was not significantly different from that of Lp(a)-apoB in statin-treated patients with elevated or normal Lp(a) (P > 0.05 in both). Lp(a)-apo(a) FCR was significantly correlated with Lp(a)-apoB in patients with elevated and normal Lp(a) concentrations (r = 0.970 and r = 0.979, respectively; all P < 0.001) with Lin's concordance test showing substantial agreement between the FCRs of Lp(a)-apo(a) and Lp(a)-apoB in patients with elevated and normal Lp(a) concentrations (rc = 0.978 and rc = 0.966, respectively). CONCLUSION: Our data indicate that the apo(a) and apoB proteins within Lp(a) particles have similar FCR and are therefore tightly coupled as an Lp(a) holoparticle in statin-treated patients with elevated and normal Lp(a) concentrations.

Lipoprotein (a) and Low-density lipoprotein apolipoprotein B metabolism following apheresis in patients with elevated lipoprotein(a) and coronary artery disease.

BACKGROUND: Lipoprotein apheresis effectively lowers lipoprotein(a) [Lp(a)] and low-density lipoprotein (LDL) by approximately 60%-70%. The rebound of LDL and Lp(a) particle concentrations following lipoprotein apheresis allows the determination of fractional catabolic rate (FCR) and hence production rate (PR) during non-steady state conditions. We aimed to investigate the kinetics of Lp(a) and LDL apolipoprotein B-100 (apoB) particles in patients with elevated Lp(a) and coronary artery disease undergoing regular apheresis. PATIENTS AND METHODS: A cross-sectional study was carried out in 13 patients with elevated Lp(a) concentration (>500 mg/L) and coronary artery disease. Lp(a) and LDL-apoB metabolic parameters, including FCR and PR were derived by the fit of a compartment model to the Lp(a) and LDL-apoB concentration data following lipoprotein apheresis. RESULTS: The FCR of Lp(a) was significantly lower than that of LDL-apoB (0.39 [0.31, 0.49] vs 0.57 [0.46, 0.71] pools/day, P = 0.03) with no significant differences in the corresponding PR (14.80 [11.34, 19.32] vs 15.73 [11.93, 20.75] mg/kg/day, P = 0.80). No significant associations were observed between the FCR and PR of Lp(a) and LDL-apoB. CONCLUSIONS: In patients with elevated Lp(a), the fractional catabolism of Lp(a) is slower than that of LDL-apoB particles, implying that different metabolic pathways are involved in the catabolism of these lipoproteins. These findings have implications for new therapies for lowering apolipoprotein(a) and apoB to prevent atherosclerotic cardiovascular disease.

Metabolism and proteomics of large and small dense LDL in combined hyperlipidemia: effects of rosuvastatin.

Small dense LDL (sdLDL) has been reported to be more atherogenic than large buoyant LDL (lbLDL). We examined the metabolism and protein composition of sdLDL and lbLDL in six subjects with combined hyperlipidemia on placebo and rosuvastatin 40 mg/day. ApoB-100 kinetics in triglyceride-rich lipoproteins (TRLs), lbLDL (density [d] = 1.019-1.044 g/ml), and sdLDL (d = 1.044-1.063 g/ml) were determined in the fed state by using stable isotope tracers, mass spectrometry, and compartmental modeling. Compared with placebo, rosuvastatin decreased LDL cholesterol and apoB-100 levels in TRL, lbLDL, and sdLDL by significantly increasing the fractional catabolic rate of apoB-100 (TRL, +45%; lbLDL, +131%; and sdLDL, +97%), without a change in production. On placebo, 25% of TRL apoB-100 was catabolized directly, 37% was converted to lbLDL, and 38% went directly to sdLDL; rosuvastatin did not alter these distributions. During both phases, sdLDL apoB-100 was catabolized more slowly than lbLDL apoB-100 (P < 0.01). Proteomic analysis indicated that rosuvastatin decreased apoC-III and apoM content within the density range of lbLDL (P < 0.05). In our view, sdLDL is more atherogenic than lbLDL because of its longer plasma residence time, potentially resulting in more particle oxidation, modification, and reduction in size, with increased arterial wall uptake. Rosuvastatin enhances the catabolism of apoB-100 in both lbLDL and sdLDL.

Triglyceride-rich lipoprotein metabolism in women: roles of apoC-II and apoC-III.

BACKGROUND: Experimental data suggest that apolipoprotein (apo) C-II and C-III regulate triglyceride-rich lipoprotein (TRL) metabolism, but there are limited studies in humans. We investigated the metabolic associations of TRLs with apoC-II and apoC-III concentrations and kinetics in women. MATERIAL AND METHODS: The kinetics of plasma apoC-II, apoC-III and very low-density lipoprotein (VLDL) apoB-100 and triglycerides were measured in the postabsorptive state using stable isotopic techniques and compartmental modelling in 60 women with wide-ranging body mass index (19·5-32·9 kg/m(2) ). RESULTS: Plasma apoC-II and apoC-III concentrations were positively associated with the concentrations of plasma triglycerides, VLDL1 - and VLDL2 -apoB-100 and triglyceride (all P < 0·05). ApoC-II production rate (PR) was positively associated with VLDL1 -apoB-100 concentration, VLDL1 triglyceride concentration and VLDL1 triglyceride PR, while apoC-II fractional catabolic rate (FCR) was positively associated with VLDL1 triglyceride FCR (all P < 0·05). No significant associations were observed between apoC-II and VLDL2 apoB-100 or triglyceride kinetics. ApoC-III PR, but not FCR, was positively associated with VLDL1 triglyceride, and VLDL2 -apoB-100 and triglyceride concentrations (all P < 0·05). No significant associations were observed between apoC-III and VLDL-apoB-100 and triglyceride kinetics. In multivariable analysis, including homoeostasis model assessment score, menopausal status and obesity, apoC-II concentration was significantly associated with plasma triglyceride, VLDL1 -apoB-100 and VLDL1 triglyceride concentrations and PR. Using the same multivariable analysis, apoC-III was significantly associated with plasma triglyceride and VLDL1 - and VLDL2 -apoB-100 and triglyceride concentrations and FCR. CONCLUSIONS: In women, plasma apoC-II and apoC-III concentrations are regulated by their respective PR and are significant, independent determinants of the kinetics and plasma concentrations of TRLs.

Effects of extended-release niacin on the postprandial metabolism of Lp(a) and ApoB-100-containing lipoproteins in statin-treated men with type 2 diabetes mellitus.

OBJECTIVE: The effects of extended-release niacin (ERN; 1-2 g/d) on the metabolism of lipoprotein(a) (Lp(a)) and apolipoprotein (apo) B-100-containing lipoproteins were investigated in 11 statin-treated white men with type 2 diabetes mellitus in a randomized, crossover trial of 12-weeks duration. APPROACH AND RESULTS: The kinetics of Lp(a) and very low-density lipoprotein (VLDL), intermediate-density lipoprotein, and low-density lipoprotein (LDL) apoB-100 were determined following a standardized oral fat load (87% fat) using intravenous administration of D3-leucine, gas chromatography-mass spectrometry, and compartmental modeling. ERN significantly decreased fasting plasma total cholesterol, LDL cholesterol, and triglyceride concentrations. These effects were achieved without significant changes in body weight or insulin resistance. ERN significantly decreased plasma Lp(a) concentration (-26.5%) and the production rates of apo(a) (-41.5%) and Lp(a)-apoB-100 (-32.1%); the effect was greater in individuals with elevated Lp(a) concentration. ERN significantly decreased VLDL (-58.7%), intermediate-density lipoprotein (-33.6%), and LDL (-18.3%) apoB-100 concentrations and the corresponding production rates (VLDL, -49.8%; intermediate-density lipoprotein, -44.7%; LDL, -46.1%). The number of VLDL apoB-100 particles secreted increased in response to the oral fat load. Despite this, total VLDL apoB-100 production over the 10-hour postprandial period was significantly decreased with ERN (-21.9%). CONCLUSIONS: In statin-treated men with type 2 diabetes mellitus, ERN decreased plasma Lp(a) concentrations by decreasing the production of apo(a) and Lp(a)-apoB-100. ERN also decreased the concentrations of apoB-100-containing lipoproteins by decreasing VLDL production and the transport of these particles down the VLDL to LDL cascade. Our study provides further mechanistic insights into the lipid-regulating effects of ERN.

Effect of dietary Fatty acids on human lipoprotein metabolism: a comprehensive update.

Dyslipidemia is a major risk factor for cardiovascular disease (CVD). Dietary fatty-acid composition regulates lipids and lipoprotein metabolism and may confer CVD benefit. This review updates understanding of the effect of dietary fatty-acids on human lipoprotein metabolism. In elderly participants with hyperlipidemia, high n-3 polyunsaturated fatty-acids (PUFA) consumption diminished hepatic triglyceride-rich lipoprotein (TRL) secretion and enhanced TRL to low-density lipoprotein (LDL) conversion. n-3 PUFA also decreased TRL-apoB-48 concentration by decreasing TRL-apoB-48 secretion. High n-6 PUFA intake decreased very low-density lipoprotein (VLDL) cholesterol and triglyceride concentrations by up-regulating VLDL lipolysis and uptake. In a study of healthy subjects, the intake of saturated fatty-acids with increased palmitic acid at the sn-2 position was associated with decreased postprandial lipemia. Low medium-chain triglyceride may not appreciably alter TRL metabolism. Replacing carbohydrate with monounsaturated fatty-acids increased TRL catabolism. Trans-fatty-acid decreased LDL and enhanced high-density lipoprotein catabolism. Interactions between APOE genotype and n-3 PUFA in regulating lipid responses were also described. The major advances in understanding the effect of dietary fatty-acids on lipoprotein metabolism has centered on n-3 PUFA. This knowledge emphasizes the importance of regulating lipoprotein metabolism as a mode to improve plasma lipids and potentially CVD risk. Additional studies are required to better characterize the cardiometabolic effects of other dietary fatty-acids.

Metabolism of apolipoprotein A-II containing triglyceride rich ApoB lipoproteins in humans.

OBJECTIVE: To characterize human triglyceride-rich lipoproteins (TRL) with and without apoA-II and to study their metabolism in vivo. METHODS: Plasma from 11 participants on a controlled diet given a bolus infusion of [D5]l-phenylalanine to label apoB was combined into four pools and applied to anti-apoA-II immunoaffinity columns. Fractions with and without apoA-II were separated into VLDL and IDL by ultracentrifugation; lipids and apolipoproteins were measured. For kinetic measurements, apoB was isolated and hydrolyzed to the constituent amino acids. Tracer enrichment was measured by GCMS. Metabolic rates were determined by SAAM-II. RESULTS: VLDL and IDL with apoA-II comprised 7% and 9% of total VLDL and IDL apoB respectively. VLDL with apoA-II was enriched in apoC-III, apoE, and cholesterol compared to VLDL without apoA-II. Mean apoB FCR of VLDL with apoA-II was significantly lower than for VLDL without apoA-II (2.80 ± 0.96 pools/day v.s. 5.09 ± 1.69 pools/day, P = 0.009). A higher percentage of VLDL with apoA-II was converted to IDL than was cleared from circulation, compared to VLDL without apoA-II (96 ± 8% vs. 45 ± 22%; P = 0.007). The rate constants for conversion of VLDL to IDL were similar for VLDL with and without apoA-II. Thus, a very low rate constant for clearance accounted for the lower FCR of VLDL with apoA-II. CONCLUSION: VLDL with apoA-II represents a small pool of VLDL particles that has a slow FCR and is predominantly converted to IDL rather than cleared from the circulation.

Association of Plasma Ceramides and Sphingomyelin With VLDL apoB-100 Fractional Catabolic Rate Before and After Rosuvastatin Treatment.

INTRODUCTION: The objective of the study was to examine post hoc associations between plasma sphingolipids and lipoprotein kinetics in men with the metabolic syndrome after rosuvastatin treatment. MATERIALS AND METHODS: Plasma sphingolipid profiling, determined by tandem mass spectrometry, was performed in a randomized, double-blind, triple-crossover trial (n = 12) of 5-week treatment periods with placebo or rosuvastatin (10 or 40 mg/d) with 2-week washouts between treatments. RESULTS AND DISCUSSION: Baseline plasma ceramides were associated with very low-density lipoprotein (VLDL) apolipoprotein (apo)-B-100 concentration (r = 0.58, P < .05) and inversely with VLDL apoB-100 fractional catabolic rate (FCR; r = -0.67, P = .02). Posttreatment changes with rosuvastatin (40 mg/d) in plasma ceramides were inversely associated with VLDL apoB-100 FCR (r = -0.62, P = .03) independent of changes in plasma triglycerides, cholesterol, and low-density lipoprotein-cholesterol. By contrast, baseline and postrosuvastatin treatment plasma sphingomyelin levels were not associated with apoB-100 kinetics. Plasma ceramides and sphingomyelin were not associated with the kinetics or concentrations of high-density lipoprotein apoA-I, and low-density lipoprotein apoB. In the metabolic syndrome, the ability of rosuvastatin to increase VLDL apoB-100 FCR may reflect ceramide-specific mechanistic actions and/or sphingolipid exchange.

Rosuvastatin Enhances the Catabolism of LDL apoB-100 in Subjects with Combined Hyperlipidemia in a Dose Dependent Manner.

Dose-associated effects of rosuvastatin on the metabolism of apolipoprotein (apo) B-100 in triacylglycerol rich lipoprotein (TRL, d < 1.019 g/ml) and low density lipoprotein (LDL) and of apoA-I in high density lipoprotein (HDL) were assessed in subjects with combined hyperlipidemia. Our primary hypothesis was that maximal dose rosuvastatin would decrease the apoB-100 production rate (PR), as well as increase apoB-100 fractional catabolic rate (FCR). Eight subjects received placebo, rosuvastatin 5 mg/day, and rosuvastatin 40 mg/day for 8 weeks each in sequential order. The kinetics of apoB-100 in TRL and LDL and apoA-I in HDL were determined at the end of each phase using stable isotope methodology, gas chromatography-mass spectrometry, and multicompartmental modeling. Rosuvastatin at 5 and 40 mg/day decreased LDL cholesterol by 44 and 54% (both P < 0.0001), triacylglycerol by 14% (ns) and 35% (P < 0.01), apoB by 30 and 36% (both P < 0.0001), respectively, and had no significant effects on HDL cholesterol or apoA-I levels. Significant decreases in plasma markers of cholesterol synthesis and increases in cholesterol absorption markers were observed. Rosuvastatin 5 and 40 mg/day increased TRL apoB-100 FCR by 36 and 46% (both ns) and LDL apoB-100 by 63 and 102% (both P < 0.05), respectively. HDL apoA-I PR increased with low dose rosuvastatin (12%, P < 0.05) but not with maximal dose rosuvastatin. Neither rosuvastatin dose altered apoB-100 PR or HDL apoA-I FCR. Our data indicate that maximal dose rosuvastatin treatment in subjects with combined hyperlipidemia resulted in significant increases in the catabolism of LDL apoB-100, with no significant effects on apoB-100 production or HDL apoA-I kinetics.

Plasma phospholipid fatty acid biomarkers of dietary fat quality and endogenous metabolism predict coronary heart disease risk: a nested case-control study within the Women's Health Initiative observational study.

BACKGROUND: Although the relationship between dietary fat quality and coronary heart disease (CHD) risk has been evaluated, typically using diet questionnaires, results are inconsistent and data in postmenopausal women are limited. Plasma phospholipid fatty acid (PL-FA) profiles, reflecting dietary intake and endogenous FA metabolism, may better predict diet-CHD risk. METHODS AND RESULTS: Using a nested case-control design, we assessed the association between plasma PL-FA profiles and CHD risk in 2448 postmenopausal women (1224 cases with confirmed CHD and 1224 controls matched for age, enrollment date, race/ethnicity, and absence of CHD at baseline and after 4.5 years of follow-up) participating in the Women's Health Initiative observational study. PL-FA profile was measured using gas chromatography. Product/precursor ratios were used to estimate stearoyl-CoA-desaturase (16:1n-7/16:0, 18:1n-9/18:0), Δ6-desaturase (20:3n-6/18:2n-6), and Δ5-desaturase (20:4n-6/20:3n-6) activities, indicators of endogenous FA metabolism. Multivariate conditional logistic regression was used to obtain odds ratios (95% CIs) for CHD risk. While no associations were observed for the predominant PL fatty acid (16:0, 18:0, 18:1n-9, and 18:2n-6), plasma PL-saturated fatty acid (1.20 [1.08 to 1.32]) and endogenously synthesized PL ω6 fatty acids (20:3n-6; 3.22 [1.95 to 5.32]), 22:5n-6; 1.63 [1.20 to 2.23]) and Δ6-desaturase (1.25 [1.11 to 1.41]) were positively associated with CHD risk. PL-ω3 fatty acids (20:5n-3; 0.73 [0.58 to 0.93], 22:5n-3; 0.56 [0.33 to 0.94], 22:6n-3; 0.56 [0.39 to 0.80]), 18:1n-7 (0.54 [0.29 to 0.99]), and Δ5-desaturase (0.78 [0.70 to 0.88]) were inversely associated with CHD risk. Results support current guidelines regarding regular fish consumption. Additional findings include associations between endogenously synthesized fatty acids and CHD risk, which were partly explained by changes in Δ6-desaturase and Δ5-desaturase indexes, suggesting that in vivo metabolism may also play an important role in predicting CHD risk in this cohort of postmenopausal women. CLINICAL TRIAL REGISTRATION URL: http://ClinicalTrials.gov, Unique identifier: NCT01864122.

Dose-dependent effects of rosuvastatin on the plasma sphingolipidome and phospholipidome in the metabolic syndrome.

CONTEXT: Statins are effective cholesterol-lowering agents that reduce cardiovascular disease risk but also have pleiotropic effects that may extend to other lipid classes. OBJECTIVE: The purpose of this article was to investigate, in a post hoc analysis, the dose-dependent effects of rosuvastatin on plasma sphingolipids and phospholipids in men with the metabolic syndrome. METHODS: Subjects (n = 12) were studied in a randomized, double-blind, triple-crossover trial of a 5-week treatment period with placebo or rosuvastatin (10 or 40 mg/day) with 2-week washouts between treatments. Plasma sphingolipid profiling was determined by liquid chromatography electrospray ionization-tandem mass spectrometry. RESULTS: Rosuvastatin at 10 mg/d (R10) and 40 mg/d (R40) significantly (all P < .001 unless stated otherwise) lowered plasma cholesterol (-34% and -42% [% change with R10 and with R40, respectively]), low-density lipoprotein cholesterol (-49% and -57%) and triglyceride (-24%, P =.03 and -42%) concentrations. Compared with placebo, R10 and R40 significantly decreased the plasma levels of total sphingolipids including those of ceramide (-33% and -37%), sphingomyelin (-27% and -31%), monohexosylceramide (-40% and -47%), dihexosylceramide (-31% and -34%), and trihexosylceramide (-29% and -31%), and GM3 gangliosides (-29% and -26%), lysophosphatidylcholine (-32% and -37%), alkylphosphatidylcholine (-19% and -19%), phosphatidylcholine (-17% and -19%), alkenylphosphatidylcholine (plasmalogen) (-20% and -22%), alkylphosphatidylethanolamine (-20%, P =.008 and -24%, P =.02), alkenylphosphatidylethanolamine (plasmalogen) (-24%, P =.003 and -23%, P =.007), phosphatidylglycerol (-24%, P =.07, -31%, P =.046), and phosphatidylinositol (-34% and -40%). No significant changes were found with phosphatidylethanolamine and phosphatidylserine. Significant dose effects were found with the majority of the plasma sphingolipids, whereas only phosphatidylcholine, lysophosphatidylcholine, alkylphosphatidylcholine, alkenylphosphatidylcholine (plasmalogen), and phosphatidylinositol had significant dose effects. Similar changes were found with plasma sphingolipids when results were normalized to the total phosphatidylcholine concentration. CONCLUSIONS: Rosuvastatin dose-dependently lowers plasma sphingolipids and phospholipids, independent of low-density lipoprotein lowering, in men with the metabolic syndrome.

Elevated remnant cholesterol in 25-hydroxyvitamin D deficiency in the general population: Mendelian randomization study.

BACKGROUND: Low plasma 25-hydroxyvitamin D [25(OH)D] levels are associated with high cardiovascular risk. This may be because that low 25(OH)D levels are associated with high levels of atherogenic lipoproteins, but whether these 2 risk factors are genetically associated is unknown. We tested this hypothesis. METHODS AND RESULTS: Using a Mendelian randomization approach, potential genetic associations between plasma levels of atherogenic lipoproteins and 25(OH)D were examined in ≤85,868 white, Danish individuals in whom we genotyped for variants affecting plasma levels of 25(OH)D, nonfasting remnant cholesterol, low-density lipoprotein-cholesterol, and high-density lipoprotein-cholesterol. Lipoprotein levels were measured in all and 25(OH)D levels in 31,435. A doubling in nonfasting remnant cholesterol levels was observationally and genetically associated with -6.0%(95% confidence interval [CI], -6.5% to -5.5%) and -8.9% (95% CI, -15% to -2.3%) lower plasma 25(OH)D levels. For low-density lipoprotein-cholesterol levels, corresponding values were -4.6% (95% CI, -5.4% to -3.7%) observationally and -11% (95% CI, -29% to +6.9%) genetically. In contrast, a halving in high-density lipoprotein-cholesterol levels was observationally associated with -1.5% (95% CI, -2.2% to -0.7%) lower but genetically associated with +20% (95% CI, +7.4% to +34%) higher plasma 25(OH)D levels. Plasma levels of lipoprotein(a) and 25(OH)D did not associate. Finally, low 25(OH)D levels did not associate genetically with levels of remnant and low-density lipoprotein-cholesterol. CONCLUSIONS: Genetically elevated nonfasting remnant cholesterol is associated with low 25(OH)D levels, whereas genetically reduced high-density lipoprotein-cholesterol is not associated with low 25(OH)D levels. These findings suggest that low 25(OH)D levels observationally is simply a marker for elevated atherogenic lipoproteins and question a role for vitamin D supplementation in the prevention of cardiovascular disease.

HER2 status in gastric/gastro-oesophageal junctional cancers: should determination of gene amplification by SISH use HER2 copy number or HER2: CEP17 ratio?

The aim of this study was to compare HER2 amplification, as determined by the HER2 copy number (CN) and the HER2/CEP17 ratio, with protein expression in gastric and gastro-oesophageal junction (G/GOJ) adenocarcinoma.HER2 immunohistochemistry (IHC) and silver in situ hybridisation (SISH) were performed in 185 cases. Modified gastric criteria were used for IHC scoring. HER2 and CEP17 CNs were counted in at least 20 cancer cells and the ratio calculated as per previously defined protocols. These two SISH methods were statistically compared against the different IHC scores.Thirty-four cases showed amplification, by both methods in 29, and either method in five. IHC score was 3+ in 29 cases; 26 showed amplification by both methods, one by ratio only and two were not amplified. IHC score was 2+ in 24 cases; three showed amplification by both methods and two by either. One each of IHC 1+ and 0 showed an increased ratio but not CN. The HER2 CN and ratio for IHC score 3+ compared to scores 2+, 1+ and 0 were significantly different (all p < 0.01). The CN for IHC 2+ vs IHC 1+ and IHC 0 was significantly different (both p < 0.01) but the ratio was not (p = 0.5711 and p = 0.2857, respectively). The CN and the ratio for scores 1+ and 0 were not significantly different (p = 0.9823 and p = 0.9910, respectively).The HER2 CN differentiates between the different IHC scores better than the HER2:CEP17 ratio. Cases that show IHC3+ and high CN may not require calculation of the ratio. Furthermore, consideration should be given to the CN when IHC negative cases appear amplified by the ratio only.

Effect of Mediterranean diet with and without weight loss on apolipoprotein B100 metabolism in men with metabolic syndrome.

OBJECTIVE: To assess the effect of a Mediterranean diet (MedDiet) with and without weight loss (WL) on apolipoprotein B100 (apoB100) metabolism in men with metabolic syndrome. APPROACH AND RESULTS: The diet of 19 men with metabolic syndrome (age, 24-62 years) was first standardized to a North American isoenergetic control diet for 5 weeks, followed by an isoenergetic MedDiet for an additional 5 weeks under full-feeding conditions (MedDiet-WL). Participants next underwent a 20-week supervised WL program under free-living conditions (-10.2 ± 2.9% body weight; P<0.01) and finally consumed the MedDiet (5 weeks) under weight-stabilizing feeding conditions (MedDiet+WL). In vivo kinetic of apoB100 was assessed in the fasted state at the end of the 3 controlled diets using a bolus of D3-leucine. Compared with the control diet, MedDiet-WL reduced low-density lipoprotein (LDL)-apoB100 pool size (-14.2%, P<0.01) primarily through an increase in LDL-apoB100 fractional catabolic rate (+30.4%, P=0.02) and increased LDL particle size (P<0.01) but had no effect on very-LDL (VLDL)-apoB100 pool size or triglyceride concentrations, despite a significant increase in VLDL-apoB100 fractional catabolic rate (+25.6%; P=0.03). MedDiet+WL had no further effect on LDL-apoB100 pool size and fractional catabolic rate but further increased LDL particle size and reduced VLDL-apoB100 pool size versus the control diet primarily through an increase in VLDL-apoB100 fractional catabolic rate (+30.7%; P<0.01). CONCLUSIONS: Consumption of MedDiet increases LDL size and reduces LDL-apoB100 concentrations primarily by increasing the catabolism of LDL even in the absence of WL in men with metabolic syndrome. MedDiet seems to have a trivial effect on VLDL concentrations and kinetics unless accompanied by significant WL. CLINICAL TRIAL REGISTRATION -URL: http://www.clinicaltrials.gov. Unique identifier: NCT00988650.

Demystifying the management of hypertriglyceridaemia.

Hypertriglyceridaemia (typical triglyceride level 1.7-5.0 mmol/l) is caused by interactions between many genetic and nongenetic factors, and is a common risk factor for atherosclerotic cardiovascular disease (CVD). Patients with hypertriglyceridaemia usually present with obesity, insulin resistance, hepatic steatosis, ectopic fat deposition, and diabetes mellitus. Hypertriglyceridaemia reflects the accumulation in plasma of proatherogenic lipoproteins, triglyceride-rich lipoprotein (TRL) remnants, and small, dense LDL particles. Mendelian randomization studies and research on inherited dyslipidaemias, such as type III dysbetalipoproteinaemia, testify that TRLs are causally related to atherosclerotic CVD. Extreme hypertriglyceridaemia (a triglyceride level >20 mmol/l) is rare, often monogenic in aetiology, and frequently causes pancreatitis. Treatment of hypertriglyceridaemia relies on correcting secondary factors and unhealthy lifestyle habits, particularly poor diet and lack of exercise. Pharmacotherapy is indicated for patients with established CVD or individuals at moderate-to-high risk of CVD, primarily those with metabolic syndrome or diabetes. Statins are the cornerstone of treatment, followed by fibrates and n-3 fatty acids, to achieve recommended therapeutic levels of plasma LDL cholesterol, non-HDL cholesterol, and apolipoprotein (apo) B-100. The case for using niacin has been weakened by the results of clinical trials, but needs further investigation. Extreme hypertriglyceridaemia requires strict dietary measures, and patients with a diagnosis of genetic lipoprotein lipase deficiency might benefit from LPL gene replacement therapy. Several therapies for regulating TRL metabolism, including inhibitors of diacylglycerol O-acyltransferase and microsomal triglyceride transfer protein, and apoC-III antisense oligonucleotides, merit further investigation in patients with hypertriglyceridaemia.

The extended abnormalities in lipoprotein metabolism in familial hypercholesterolemia: developing a new framework for future therapies.

Familial hypercholesterolemia (FH) is a dominantly inherited disorder characterized by marked elevation of plasma low-density lipoprotein (LDL) cholesterol concentrations and premature coronary artery disease (CHD). In addition to impaired LDL receptor-mediated clearance of LDL particles, in vitro and in vivo studies suggest that hepatic oversecretion of apolipoprotein (apo) B may contribute to the hypercholesterolemia in FH. This may be due to an effect of the expanded hepatic pool of cholesterol (a consequence of increased receptor-independent uptake of LDL) and/or a direct effect of the LDL receptor on apoB secretion. Hepatic oversecretion of apoB may depend on the type and severity of the genetic mutation causing FH. FH can also increase plasma Lp(a) concentration by an undefined mechanism that may not directly involve the LDL receptor pathway. Decreased catabolism of triglyceride-rich lipoproteins could also be due to deficient LDL receptor function, accounting for postprandial dyslipidemia in FH. The metabolism of high-density lipoprotein (HDL) in FH is poorly understood, but preliminary data suggest abnormal HDL composition and functionality, as well as altered transport of apoA-I. Beyond effects related to specific genetic defects in the LDL pathway, co-existing secondary causes, particularly obesity and insulin resistance, and other genetic variants may also perturb lipoprotein metabolism in individuals with FH. Furthermore, residual risk remains high in statin-treated FH. Knowledge of an extended metabolic framework will, therefore, provide the basis for judiciously selecting new pharmacotherapies to treat FH, including apoB antisense oligonucleotides, microsomal transfer protein (MTP) inhibitors and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors.

Elevated interleukin-12 and interleukin-18 in chronic kidney disease are not associated with arterial stiffness.

BACKGROUND: Chronic kidney disease (CKD) patients are at increased risk of cardiovascular disease (CVD) mortality compared to the general population. Evidence suggests inflammation is important in the pathogenesis of CVD in CKD and inflammatory bio-markers such as C-reactive protein (CRP) and pro-atherogenic cytokines such as interleukin(IL)-6, IL-12 and IL-18 are associated with CVD-related outcomes in the general population and CKD. In the general population, IL-12 and IL-18 are implicated in the pathogenesis of atherosclerosis and are associated with acute CVD events, including mortality. Although IL-12 and IL-18 are increased in CKD, extrapolating an equally important role for these cytokines in the pathogenesis of CVD in CKD remains uncertain. In this study we aim to compare serum levels of pro-atherogenic cytokines in non-dialysis CKD patients and healthy individuals. We will also assess the relationship between these cytokines and arterial stiffness, a surrogate marker of CVD. METHODS: We performed a case-control study examining IL-12, IL-18, aortic pulse wave velocity (PWV) and augmentation index (AIx) in healthy volunteers (n=69) and stage 3-4 (n=70) and stage 5 (n=84) CKD subjects. RESULTS: IL12 levels were elevated in stage 3-4 (129 pg/mL; IQR 56-222) and stage 5 (125 pg/mL; IQR 45-240) CKD in comparison to healthy controls (65 pg/mL; IQR 5-229). IL18 was elevated in CKD stage 5 (617 pg/mL; IQR 468-793) in comparison to CKD stage 3-4 (417 pg/mL; IQR 288-494) and healthy controls (359 pg/mL; IQR 238-548). In multivariate analysis, only glomerular filtration rate (GFR) remained an independent predictor of IL-18 (p<0.01). Neither IL-12 nor IL-18 were associated with PWV or AIx. CONCLUSION: IL-12 and IL-18 are elevated during the earlier stages of CKD but are not associated with arterial stiffness. The association with GFR suggests that IL-18 is largely dependent upon renal clearance.

Insulin resistance and the metabolic syndrome are associated with arterial stiffness in patients with chronic kidney disease.

BACKGROUND: Insulin resistance (IR) and the metabolic syndrome (MetS) may contribute to cardiovascular risk in chronic kidney disease (CKD). We examine the association between IR and vascular function in CKD. Furthermore, we define the prevalence of MetS and examine the association between defining MetS and vascular function. METHODS: This cross-sectional study of 71 stage 3-4 CKD subjects assessed arterial stiffness (pulse wave velocity (PWV) and endothelial dysfunction (ED). IR was assessed using Homeostasis Model Assessment-IR (HOMA-IR). MetS was defined by the unified International Diabetes Federation and American Heart Association/National Heart Lung and Blood Institute criteria. RESULTS: CKD subjects with HOMA-IR score above the median had significantly higher body mass index and waist circumference. They also had higher PWV, higher triglycerides with lower high-density lipoprotein concentration (P < 0.05). Age, systolic blood pressure, and HOMA-IR were independently associated with PWV, even after exclusion of diabetic subjects (n = 16) (P ≤ 0.05). MetS was more prevalent in CKD (78.9%) than controls (2.5%). MetS in CKD was associated with increased PWV (MetS(+) geometric mean = 9.5 m/s, 95% confidence interval (95% CI) = 8.9-10.2 m/s; vs. MetS(-) 8.1 m/s, 95% CI = 7.1-9.3 m/s; P = 0.03) but not ED. In a multiple logistic regression analysis, PWV higher than the median was independently associated with dysglycemia. CONCLUSIONS: IR is independently associated with arterial stiffness, even in nondiabetic CKD. MetS is common and identified a subgroup of CKD patients with increased arterial stiffness, which is associated with dysglycemia.