Supplementation of Seaweed Extracts to the Diet Reduces Symptoms of Alzheimer's Disease in the APPswePS1ΔE9 Mouse Model.

We previously demonstrated that diet supplementation with seaweed Sargassum fusiforme (S. fusiforme) prevented AD-related pathology in a mouse model of Alzheimer's Disease (AD). Here, we tested a lipid extract of seaweed Himanthalia elongata (H. elongata) and a supercritical fluid (SCF) extract of S. fusiforme that is free of excess inorganic arsenic. Diet supplementation with H. elongata extract prevented cognitive deterioration in APPswePS1ΔE9 mice. Similar trends were observed for the S. fusiforme SCF extract. The cerebral amyloid-ß plaque load remained unaffected. However, IHC analysis revealed that both extracts lowered glial markers in the brains of APPswePS1ΔE9 mice. While cerebellar cholesterol concentrations remained unaffected, both extracts increased desmosterol, an endogenous LXR agonist with anti-inflammatory properties. Both extracts increased cholesterol efflux, and particularly, H. elongata extract decreased the production of pro-inflammatory cytokines in LPS-stimulated THP-1-derived macrophages. Additionally, our findings suggest a reduction of AD-associated phosphorylated tau and promotion of early oligodendrocyte differentiation by H. elongata. RNA sequencing on the hippocampus of one-week-treated APPswePS1ΔE9 mice revealed effects of H. elongata on, amongst others, acetylcholine and synaptogenesis signaling pathways. In conclusion, extracts of H. elongata and S. fusiforme show potential to reduce AD-related pathology in APPswePS1ΔE9 mice. Increasing desmosterol concentrations may contribute to these effects by dampening neuroinflammation.

Composition and distribution of lipoproteins after evolocumab in familial dysbetalipoproteinemia: A randomized controlled trial.

BACKGROUND: Proprotein convertase subtilisin kexin type 9 (PCSK9) monoclonal antibodies (mAbs) reduce fasting and post fat load cholesterol in non-HDL and intermediate density lipoprotein (IDL) in familial dysbetalipoproteinemia (FD). However, the effect of PCSK9 mAbs on the distribution and composition of atherogenic lipoproteins in patients with FD is unknown. OBJECTIVE: To evaluate the effect of the PCSK9 mAb evolocumab added to standard lipid-lowering therapy in patients with FD on fasting and post fat load lipoprotein distribution and composition. METHODS: Randomized placebo-controlled double-blind crossover trial comparing evolocumab (140 mg subcutaneous every 2 weeks) with placebo during two 12-week treatment periods. Patients received an oral fat load at the start and end of each treatment period. Apolipoproteins (apo) were measured with ultracentrifugation, gradient gel electrophoresis, retinyl palmitate and SDS-PAGE. RESULTS: PCSK9 mAbs significantly reduced particle number of all atherogenic lipoproteins, with a stronger effect on smaller lipoproteins than on larger lipoproteins (e.g. IDL-apoB 49%, 95%confidence interval (CI) 41-59 and very low-density lipoprotein (VLDL)-apoB 33%, 95%CI 16-50). Furthermore, PCSK9 mAbs lowered cholesterol more than triglyceride (TG) in VLDL, IDL and low-density lipoprotein (LDL) (e.g. VLDL-C 48%, 95%CI 29-63%; and VLDL-TG 20%, 95%CI 6.3-41%). PCSK9 mAbs did not affect the post fat load response of chylomicrons. CONCLUSION: PCSK9 mAbs added to standard lipid-lowering therapy in FD patients significantly reduced lipoprotein particle number, in particular the smaller and more cholesterol-rich lipoproteins (i.e. IDL and LDL). PCSK9 mAbs did not affect chylomicron metabolism. It seems likely that the observed effects are achieved by increased hepatic lipoprotein clearance, but the specific working mechanism of PCSK9 mAbs in FD patients remains to be elucidated.

Altered Functionality of Lipoprotein(a) Impacts on Angiogenesis in Diabetic Retinopathy.

Purpose: Diabetic retinopathy (DR) is a complication of type 2 diabetes mellitus (T2DM). Lipoprotein(a) (Lp(a)) contributes to the progression of DR, but how is unclear. In homeostasis of the retinal microvasculature, myeloid-derived pro-angiogenic cells (PACs) also play a pivotal role, and fail to function properly in diabetic conditions. Here, we explored the putative contribution of Lp(a) from patients with T2DM with/without DR and healthy controls on inflammation and angiogenesis of retinal endothelial cells (RECs), and on PAC differentiation. Subsequently, we compared the lipid composition of Lp(a) from patients to that from healthy controls. Methods: Lp(a)/LDL obtained from patients and healthy controls were added to TNF-alpha-activated RECs. Expression of VCAM-1/ICAM-1 was measured using flowcytometry. Angiogenesis was determined in REC-pericyte co-cultures stimulated by pro-angiogenic growth factors. PAC differentiation from peripheral blood mononuclear cells was determined by measuring expression of PAC markers. The lipoprotein lipid composition was quantified using detailed lipidomics analysis. Results: Lp(a) from patients with DR (DR-Lp(a)) failed to block TNF-alpha-induced expression of VCAM-1/ICAM-1 in REC whereas Lp(a) from healthy controls (healthy control [HC]-Lp(a)) did. DR-Lp(a) increased REC angiogenesis more than HC-Lp(a) did. Lp(a) from patients without DR showed intermediate profiles. HC-Lp(a) reduced the expression of CD16 and CD105 in PAC, but T2DM-Lp(a) did not. Phosphatidylethanolamine content was lower in T2DM-Lp(a) than in HC-Lp(a). Conclusions: DR-Lp(a) does not show the anti-inflammatory capacity seen with HC-Lp(a), but increases REC angiogenesis, and affects PAC differentiation less than HC-Lp(a). These functional differences in Lp(a) in T2DM-related retinopathy are associated with alterations in the lipid composition as compared to healthy conditions.

Low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol measurement in Familial Dysbetalipoproteinemia.

AIM: To compare LDL-C concentrations using the Friedewald formula, the Martin-Hopkins formula, a direct assay and polyacrylamide gradient gel electrophoresis (PGGE) to the reference standard density gradient ultracentrifugation in patients with Familial Dysbetalipoproteinemia (FD) patients. We also compared non-HDL-cholesterol concentrations by two methods. METHODS: For this study data from 28 patients with genetically confirmed FD from the placebo arm of the EVOLVE-FD trial were used. Four different methods for determining LDL-C were compared with ultracentrifugation. Non-HDL-C was measured with standard assays and compared to ultracentrifugation. Correlation coefficients and Bland-Altman plots were used to compare the methods. RESULTS: Mean age of the 28 FD patients was 62 ± 9 years, 43 % were female and 93 % had an ɛ2ɛ2 genotype. LDL-C determined by Friedewald (R2 = 0.62, p <0.01), Martin-Hopkins (R2 = 0.50, p = 0.01) and the direct assay (R2 = 0.41, p = 0.03) correlated with density gradient ultracentrifugation. However, Bland-Altman plots showed considerable over- or underestimation by the four methods compared to ultracentrifugation. Non-HDL-C showed good correlation and agreement. CONCLUSION: In patients with FD, all four methods investigated over- or underestimated LDL-C concentrations compared with ultracentrifugation. In contrast, standard non-HDL-C assays performed well, emphasizing the use of non-HDL-C in patients with FD.

Effects of dapagliflozin on postprandial lipid metabolism in type 2 diabetes mellitus.

Objectives: Sodium-glucose cotransporter 2 inhibitors (SGLT2i) modulate lipid metabolism and improve cardiovascular morbidity and mortality in patients with type 2 diabetes mellitus (T2DM). The exact cardioprotective mechanism of SGLT2i is unclear. We evaluated the effects of SGLT2i on postprandial lipids, lipoprotein concentrations, glucose and fatty acids. Design: A placebo-controlled randomized, proof-of-concept study. Methods: Fourteen male patients with T2DM on intensive insulin regimen were randomly and double-blind allocated to 12 weeks dapagliflozin (10 mg) or placebo. Postprandial effects were assessed with an 8-h standardized oral fat loading test. Results: Mean glycated A1c did not change by dapagliflozin, but the mean daily insulin dose was significantly reduced. Although dapagliflozin did not affect fasting or postprandial levels of glucose and insulin, it increased the postprandial levels of glucagon. While fasting levels of free fatty acids and beta-hydroxybutyrate (bHBA) were unchanged, dapagliflozin significantly increased the postprandial bHBA response. This was seen in the context of increased postprandial glucagon levels by dapagliflozin, without influencing postprandial insulin or glucose levels. Dapagliflozin did not affect fasting or postprandial plasma cholesterol and triglycerides nor postprandial inflammatory markers. Fasting apolipoprotein B48 was decreased without affecting the postprandial response. Markers of inflammation and vascular function did not change. Conclusion: Treatment with dapagliflozin of patients with T2DM led to a reduction of fasting chylomicron remnants and increased postprandial ketone bodies compared to placebo suggesting enhanced hepatic fatty acid oxidation. The latter may have been caused by decreasing the insulin-glucagon ratio. The beneficial clinical effects seen in the trials using dapagliflozin most likely are not due to effects on postprandial inflammation nor postprandial lipemia.

Appetite-regulating hormone trajectories and relationships with fat mass development in term-born infants during the first 6 months of life.

BACKGROUND: The first 6 months of life are a critical window for adiposity programming. Appetite-regulating hormones (ARH) are involved in food intake regulation and might, therefore, play a role in adiposity programming. Studies examining ARH in early life are limited. PURPOSE: To investigate ghrelin, peptide YY (PYY) and leptin until 6 months and associations with fat mass percentage (FM%), infant feeding and human milk macronutrients. PROCEDURES: In 297 term-born infants (Sophia Pluto Cohort), ghrelin (acylated), PYY and leptin were determined at 3 and 6 months, with FM% measurement by PEAPOD. Exclusive breastfeeding (BF) was classified as BF ≥ 3 months. Human milk macronutrients were analyzed (MIRIS Human Milk Analyzer). MAIN FINDINGS: Ghrelin increased from 3 to 6 months (p < 0.001), while PYY decreased (p < 0.001), resulting in increasing ghrelin/PYY ratio. Leptin decreased. Leptin at 3 months was higher in girls, other ARH were similar between sexes. Leptin at 3 and 6 months correlated with FM% at both ages(R ≥ 0.321, p ≤ 0.001) and gain in FM% from 1 to 6 months(R ≥ 0.204, p = 0.001). In BF infants, also ghrelin and ghrelin/PYY ratio correlated with this gain in FM%. Exclusively BF infants had lower ghrelin and higher PYY compared to formula fed infants at 3 months (p ≤ 0.039). ARH did not correlate with macronutrients. CONCLUSIONS: Increasing ghrelin and decreasing PYY, thus increasing ghrelin/PYY ratio, suggests an increasing orexigenic drive until 6 months. ARH were different between BF and FF infants at 3 months, but did not correlate with human milk macronutrients. Ghrelin and leptin, but not PYY, correlated with more FM development during the first 6 months, suggesting that they might be involved in adiposity programming.

A placebo-controlled proof-of-concept study of alirocumab on postprandial lipids and vascular elasticity in insulin-treated patients with type 2 diabetes mellitus.

AIM: Type 2 diabetes mellitus (T2DM) is associated with an increased risk of cardiovascular disease (CVD) linked to atherogenic dyslipidaemia and postprandial hyperlipidaemia. Alirocumab, a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor, improves CVD risk by reducing the concentration of low-density lipoprotein-cholesterol (LDL-C). However, effects of PCK9 inhibitors on other aspects of diabetic dyslipidaemia, particularly in the postprandial situation, are less clear. MATERIAL AND METHODS: Twelve male patients with T2DM on an intensive insulin regimen completed a 6-week randomized, double-blind, placebo-controlled, proof-of-concept study. Participants received three biweekly dosages of subcutaneous alirocumab (150 mg) or placebo. Before and after the intervention, fasting and postprandial triglyceride (TG) plasma levels, apolipoprotein (apo) B48, lipoprotein composition isolated by ultracentrifugation, vascular function and markers of inflammation were evaluated. RESULTS: Alirocumab treatment reduced fasting plasma TG levels (between group median change -24.7%; P = 0.018) and fasting apoB48 serum levels (-35.9%; P = 0.039) compared with placebo. Alirocumab reduced the plasma TG area under the curve (AUC) (-26.4%; P = 0.006) and apoB48 AUC (-55.7%; P = 0.046), as well as plasma TG incremental AUC (-21.4%; P = 0.04) and apoB48 incremental AUC (-26.8%; P = 0.02). In addition, alirocumab reduced fasting and postprandial TG levels in very low-density lipoprotein (VLDL) and LDL. Alirocumab improved fasting pulse wave velocity, but no changes in postprandial markers of inflammation were observed. CONCLUSIONS: In addition to the well-known LDL-C-reducing effects, 6 weeks of alirocumab treatment lowered both fasting and postprandial plasma TG levels by reducing the TG levels in VLDL and LDL and the concentration of intestinal remnants.

Appetite-regulating hormones in early life and relationships with type of feeding and body composition in healthy term infants.

INTRODUCTION: Body composition in early life influences development of obesity during childhood and beyond. Appetite-regulating hormones (ARH) play a role in regulation of food intake and might thus influence body composition in later life. Studies on associations between ARH and body composition in early life are limited. METHODS: In 197 healthy term infants, we measured serum fasting levels of ghrelin, leptin, insulin, glucose-dependent insulinotropic peptide (GIP), pancreatic polypeptide (PP) and peptide YY (PYY) at 3 months and in 41 infants also at 6 months and their associations with type of feeding and longitudinal fat mass percentage (FM%) measured by air displacement plethysmography at 1, 3 and 6 months and abdominal visceral and subcutaneous fat, measured by ultrasound, at 3 and 6 months. RESULTS: Infants with formula feeding for 3 months had significantly higher serum levels of ghrelin, leptin, insulin, GIP and PP (p = 0.026, p = 0.018, p = 0.002, p < 0.001, resp.) and lower serum levels of PYY (p = 0.002) at 3 months than breastfed infants. Leptin and ghrelin correlated positively with FM% at 3 months and insulin with change in FM% between 1 and 3 months (r = 0.40, p < 0.001, r = 0.23, p < 0.05, r = 0.22, p < 0.01, resp.). Leptin at 3 months correlated with subcutaneous fat at 3 months (r = 0.23, p < 0.001), but not with visceral fat. Other ARH did not correlate with body composition. CONCLUSION: Formula-fed infants had a different profile of ARH than breastfed infants, suggesting that lower levels of ghrelin, leptin and insulin in breastfed infants contribute to the protective role of breastfeeding against obesity development. Leptin, ghrelin and insulin were associated with fat mass percentage or its changes.

Familial hypercholesterolaemia: cholesterol efflux and coronary disease.

BACKGROUND: Coronary heart disease (CHD) risk inversely associates with levels of high-density lipoprotein cholesterol (HDL-C). The protective effect of HDL is thought to depend on its functionality, such as its ability to induce cholesterol efflux. MATERIALS AND METHODS: We compared plasma cholesterol efflux capacity between male familial hypercholesterolaemia (FH) patients with and without CHD relative to their non-FH brothers, and examined HDL constituents including sphingosine-1-phosphate (S1P) and its carrier apolipoprotein M (apoM). RESULTS: Seven FH patients were asymptomatic and six had experienced a cardiac event at a mean age of 39 years. Compared to their non-FH brothers, cholesterol efflux from macrophages to plasma from the FH patients without CHD was 16 ± 22% (mean ± SD) higher and to plasma from the FH patients with CHD was 7 ± 8% lower (P = 0·03, CHD vs. non-CHD). Compared to their non-FH brothers, FH patients without CHD displayed significantly higher levels of HDL-cholesterol, HDL-S1P and apoM, while FH patients with CHD displayed lower levels than their non-FH brothers. CONCLUSIONS: A higher plasma cholesterol efflux capacity and higher S1P and apoM content of HDL in asymptomatic FH patients may play a role in their apparent protection from premature CHD.

Identifying genetic risk variants for coronary heart disease in familial hypercholesterolemia: an extreme genetics approach.

Mutations in the low-density lipoprotein receptor (LDLR) gene cause familial hypercholesterolemia (FH), a disorder characterized by coronary heart disease (CHD) at young age. We aimed to apply an extreme sampling method to enhance the statistical power to identify novel genetic risk variants for CHD in individuals with FH. We selected cases and controls with an extreme contrast in CHD risk from 17,000 FH patients from the Netherlands, whose functional LDLR mutation was unequivocally established. The genome-wide association (GWA) study was performed on 249 very young FH cases with CHD and 217 old FH controls without CHD (above 65 years for males and 70 years of age for females) using the Illumina HumanHap550K chip. In the next stage, two independent samples (one from the Netherlands and one from Italy, Norway, Spain, and the United Kingdom) of FH patients were used as replication samples. In the initial GWA analysis, we identified 29 independent single nucleotide polymorphisms (SNPs) with suggestive associations with premature CHD (P<1 × 10(-4)). We examined the association of these SNPs with CHD risk in the replication samples. After Bonferroni correction, none of the SNPs either replicated or reached genome-wide significance after combining the discovery and replication samples. Therefore, we conclude that the genetics of CHD risk in FH is complex and even applying an 'extreme genetics' approach we did not identify new genetic risk variants. Most likely, this method is not as effective in leveraging effect size as anticipated, and may, therefore, not lead to significant gains in statistical power.

The impact of partial and complete loss-of-function mutations in endothelial lipase on high-density lipoprotein levels and functionality in humans.

BACKGROUND: Endothelial lipase is a phospholipase with activity against high-density lipoprotein. Although a small number of mutations in LIPG have been described, the role of LIPG in protection against atherosclerosis is unclear. METHODS AND RESULTS: We identified 8 loss-of-function (LOF) mutations in LIPG in individuals with high-density lipoprotein cholesterol. Functional analysis confirmed that most rare mutations abolish lipase activity in vitro, indicating complete LOF, whereas 2 more common mutations N396S and R476W reduce activity by ≈50%, indicating partial LOF and implying ≈50% and ≈75% remaining endothelial lipase function in heterozygous complete LOF and partial LOF mutation carriers, respectively. complete LOF mutation carriers had significantly higher plasma high-density lipoprotein cholesterol levels compared with partial LOF mutation carriers. Apolipoprotein B-depleted serum from complete LOF carriers showed significantly enhanced cholesterol efflux acceptor capacity, whereas only trends were observed in partial LOF carriers. Carriers of LIPG mutations exhibited trends toward reduced coronary artery disease in 4 independent cohorts (meta-analysis odds ratio, 0.7; P=0.04). CONCLUSIONS: Our data suggest that the impact of LIPG mutations is directly related to their effect on endothelial lipase function and support that antagonism of endothelial lipase function improves cardioprotection.

Red wine extract protects against oxidative-stress-induced endothelial senescence.

Red wine polyphenols may preserve endothelial function during aging. Endothelial cell senescence enhances age-related endothelial dysfunction. We investigated whether RWE (red wine extract) prevents oxidative-stress-induced senescence in HUVECs (human umbilical-vein endothelial cells). Senescence was induced by exposing HUVECs to tBHP (t-butylhydroperoxide), and quantified by senescence-associated ß-galactosidase staining. RWE (0-50 µg/ml) concentration dependently decreased senescence by maximally 33±7.1%. RWE prevented the senescence-associated increase in p21 protein expression, inhibited tBHP-induced DNA damage of endothelial cells and induced relaxation of PCAs (porcine coronary arteries). Inhibition of SIRT1 (sirtuin 1) by sirtinol partially reversed the effect of RWE on tBHP-induced senescence, whereas both the NOS (nitric oxide synthase) inhibitor L-NMMA (NG-monomethyl-L-arginine) and the COX (cyclo-oxygenase) inhibitor indomethacin fully inhibited it. Furthermore, incubation of HUVECs with RWE increased eNOS (endothelial NOS) and COX-2 mRNA levels as well as phosphorylation of eNOS at Ser1177. RWE protects endothelial cells from tBHP-induced senescence. NO and COX-2, in addition to activation of SIRT1, play a critical role in the inhibition of senescence induction in human endothelial cells by RWE.

Apolipoprotein isoform E4 does not increase coronary heart disease risk in carriers of low-density lipoprotein receptor mutations.

BACKGROUND: In humans, the E4 allele of the apolipoprotein E gene is associated with increased coronary heart disease risk. Surprisingly, in rodents, apolipoprotein E4 only accelerates the atherosclerotic process when transgenic for the human low-density lipoprotein receptor (LDLR) protein. We therefore investigated whether the LDLR locus interacted with the apolipoprotein E gene genotype on coronary heart disease risk in patients clinically diagnosed with familial hypercholesterolemia with and without LDLR mutation. We investigated whether the presence of an LDLR mutation diminishing LDLR function was protective in E4/E4 carriers. METHODS AND RESULTS: In a cohort of 2400 patients clinically diagnosed with familial hypercholesterolemia, we found an LDLR gene mutation in 1383 patients, whereas in 1013 patients, such mutation was not present. In 92 patients homozygous for the apolipoprotein E4, the presence of an LDLR mutation conferred lower coronary heart disease risk (hazard ratio, 0.16; 95% CI, 0.05-0.58; P=0.005). Mirroring these results, the apolipoprotein E4/E4 genotype was also associated with lower coronary heart disease risk in patients with familial hypercholesterolemia with an LDLR mutation (hazard ratio, 0.26; hazard ratio, 0.08-0.80; P=0.02). CONCLUSIONS: LDLR function is key to the detrimental effects of apolipoprotein E4 in humans. Kinetic studies in humans are now required to study the consequences of our observation for prevention of both coronary heart disease and Alzheimer disease.

Cerebral accumulation of dietary derivable plant sterols does not interfere with memory and anxiety related behavior in Abcg5-/- mice.

Plant sterols such as sitosterol and campesterol are frequently applied as functional food in the prevention of atherosclerosis. Recently, it became clear that plasma derived plant sterols accumulate in murine brains. We questioned whether plant sterols in the brain are associated with alterations in brain cholesterol homeostasis and subsequently with brain functions. ATP binding cassette (Abc)g5-/- mice, a phytosterolemia model, were compared to Abcg5+/+ mice for serum and brain plant sterol accumulation and behavioral and cognitive performance. Serum and brain plant sterol concentrations were respectively 35-70-fold and 5-12-fold increased in Abcg5-/- mice (P<0.001). Plant sterol accumulation resulted in decreased levels of desmosterol (P<0.01) and 24(S)-hydroxycholesterol (P<0.01) in the hippocampus, the brain region important for learning and memory functions, and increased lanosterol levels (P<0.01) in the cortex. However, Abcg5-/- and Abcg5+/+ displayed no differences in memory functions or in anxiety and mood related behavior. The swimming speed of the Abcg5-/- mice was slightly higher compared to Abcg5+/+ mice (P<0.001). In conclusion, plant sterols in the brains of Abcg5-/- mice did have consequences for brain cholesterol metabolism, but did not lead to an overt phenotype of memory or anxiety related behavior. Thus, our data provide no contra-indication for nutritional intake of plant sterol enriched nutrition.

Liver X receptor activation restores memory in aged AD mice without reducing amyloid.

Alterations in cerebral cholesterol metabolism are thought to play a role in the progression of Alzheimer's disease (AD). Liver X receptors (LXRs) are key regulators of cholesterol metabolism. The synthetic LXR activator, T0901317 has been reported to improve memory functions in animal models for AD and to reduce amyloid-ß (Aß) deposition in the brain. Here we provide evidence that long-term administration of T0901317 to aged, 21-month-old APPSLxPS1mut mice restores impaired memory. Cerebral cholesterol turnover was enhanced as indicated by the increased levels of brain cholesterol precursors and the upregulation of LXR-target genes Abca1, Abcg1, and Apoe. Unexpectedly, the improved memory functions in the APPSLxPS1mut mice after T0901317 treatment were not accompanied by a decrease in Aß plaque load in the cortex or hippocampus DG, CA1 or CA3. T0901317 administration also enhanced cerebral cholesterol turnover in aged C57BL/6NCrl mice, but did not further improve their memory functions. In conclusion, long-term activation of the LXR-pathway restored memory functions in aged APPSLxPS1mut mice with advanced Aß deposition. However the beneficial effects of T0901317 on memory in the APPSLxPS1mut mice were independent of the Aß plaque load in the hippocampus, but were associated with enhanced brain cholesterol turnover.

Alterations in brain cholesterol metabolism in the APPSLxPS1mut mouse, a model for Alzheimer's disease.

Disturbances in cerebral cholesterol metabolism have been implicated in the pathogenesis of Alzheimer's disease (AD). Here, we provide evidence that alterations in brain cholesterol homeostasis also can be a consequence of disease progression. We found that APPSLxPS1mut mice, at the age of 9 months when AD-like pathology starts to develop, display increased levels of the cholesterol precursor desmosterol and of the cholesterol metabolite 27-hydroxy(OH)cholesterol in their cerebellum in comparison with wild-type controls. At the age of 21 months, when APPSLxPS1mut brain contains abundant amyloid deposits, desmosterol levels had further increased (> 200% in comparison with wild-type mice) in all brain regions examined. 24(S)-OHcholesterol levels were increased in hippocampus and cerebellum of the APPSLxPS1mut mice, while 27-OHcholesterol levels were increased in cerebellum exclusively. Brain cholesterol levels remained unaffected. In line with the fact that desmosterol and 24(S)-OHcholesterol are Liver X Receptor (LXR) activators, the LXR-target genes Abca1 and Apoc1 were upregulated predominantly in hippocampus of APPSLxPS1mut mice at both ages evaluated. The reduced expression of the enzyme that converts desmosterol into cholesterol, the Selective AD indicator 1 gene (Seladin-1/Dhcr24), in both cortex and cerebellum may underlie the increased desmosterol levels in 21 month-old APPSLxPS1mut mice.

The effect of statin alone or in combination with ezetimibe on postprandial lipoprotein composition in obese metabolic syndrome patients.

INTRODUCTION: Fasting and postprandial hypertriglyceridemia are essential features of metabolic syndrome. Statins decrease fasting lipid levels but fail to reduce fat load induced hypertriglyceridemia. We established whether ezetimibe combined with simvastatin differently influences post fat load lipid levels and lipoprotein composition as compared to simvastatin 80mg monotherapy in obese male metabolic syndrome patients. METHODS: Prospective, randomized, double blind, crossover trial. Male obese metabolic syndrome (ATPIII) patients (n=19) were treated with simvastatin 80mg and simvastatin/ezetimibe 10mg/10mg for 6 weeks. At the start of the study and after each treatment period oral fat loading tests were performed. Lipoprotein fractions (triglyceride-rich lipoproteins (TRL), IDL, LDL, and HDL) were isolated by density gradient ultracentrifugation. Postprandial changes in lipid levels were integrated as areas under the curve (AUCs). RESULTS: Fasting LDL-C, RLP-C and triglycerides were lowered equally by both simvastatin 80mg and simvastatin/ezetimibe 10mg/10mg. Also postprandial plasma triglyceride levels (net AUC-TG) were equally lowered after both treatments (5.16+/-0.50mmolh/l after simvastatin/ezetimibe 10mg/10mg and 6.09+/-0.71mmolh/l after simvastatin 80mg) compared to fat loading without treatment (6.64+/-0.86mmolh/l). In addition, triglyceride-content in lipoprotein fractions after fat load (net AUCs) were also equally reduced after both treatments. Similarly, TRL. IDL and LDL cholesterol and apoB concentrations were equally affected by both treatment regimens, leading to a reduced number of circulating particles, in both conditions. However the composition of these particles remained the same. CONCLUSION: Simvastatin 80mg and simvastatin/ezetimibe 10mg/10mg were equally effective in reducing fasting and post fat load plasma lipid, and lipoprotein concentrations and lipoprotein composition in obese metabolic syndrome patients.

Lipid-lowering therapy does not affect the postprandial drop in high density lipoprotein-cholesterol (HDL-c) plasma levels in obese men with metabolic syndrome: a randomized double blind crossover trial.

INTRODUCTION: The postprandial lipid metabolism in metabolic syndrome patients is disturbed and may add to the increased cardiovascular risk in these patients. It is not known whether postprandial high density lipoprotein-cholesterol (HDL-c) metabolism is also affected and whether this can be influenced by statin and/or ezetimibe treatment. METHODS: Prospective, randomized, double blind, crossover trial comparing simvastatin 80 mg with simvastatin/ezetimibe 10 mg/10 mg treatment for 6 weeks on postprandial HDL-c metabolism in 15, nonsmoking, male, obese metabolic syndrome patients (Adult Treatment Panel III, ATPIII). Only study medication was allowed. HDL-c concentrations, cholesteryl ester transfer (CET), CET protein (CETP) mass and adiponectin were measured before and after oral fat loading. ClinicalTrials.gov NCT00189085. RESULTS: Plasma HDL-c levels remained stable during continuous fasting following an overnight fast. Pre-fat load HDL-c concentrations without treatment, after simvastatin and simvastatin/ezetimibe treatment were 1.15 +/- 0.04, 1.16 +/- 0.05 and 1.11 +/- 0.04 mmol/l. Fat load induced a 11% drop in HDL-c plasma levels; 1.02 +/- 0.05 mmol/l (P < 0.001) which was not affected by either therapy. Triglyceride levels during fat load were similar after both treatments. Total CET increased from 9.73 +/- 0.70 to 12.20 +/- 0.67 nmol/ml/h (P = 0.004). Four hours after fat loading CETP mass was increased while adiponectin levels were decreased, irrespective of treatment. DISCUSSION: HDL-c levels decrease as CET increases after fat loading in obese metabolic syndrome patients. This is not influenced by either simvastatin or simvastatin/ezetimibe treatment. After fat loading, CETP mass and CET increased, and adiponectin decreased pointing towards a potential role for intra-abdominal fat. Decreased postprandial HDL-c levels may contribute to the increased cardiovascular risk in metabolic syndrome patients on top of already low HDL-c levels.