The effects of APOE4 and familial Alzheimer's disease mutations on free fatty acid profiles in mouse brain are age- and sex-dependent.

APOE4 encoding apolipoprotein (Apo)E4 is the strongest genetic risk factor for Alzheimer's disease (AD). ApoE is key in intercellular lipid trafficking. Fatty acids are essential for brain integrity and cognitive performance and are implicated in neurodegeneration. We determined the sex- and age-dependent effect of AD and APOE4 on brain free fatty acid (FFA) profiles. FFA profiles were determined by LC-MS/MS in hippocampus, cortex, and cerebellum of female and male, young (≤3 months) and older (>5 months), transgenic APOE3 and APOE4 mice with and without five familial AD (FAD) mutations (16 groups; n = 7-10 each). In the different brain regions, females had higher levels than males of either saturated or polyunsaturated FFAs or both. In the hippocampus of young males, but not of older males, APOE4 and FAD each induced 1.3-fold higher levels of almost all FFAs. In young and older females, FAD and to a less extent APOE4-induced shifts among saturated, monounsaturated, and polyunsaturated FFAs without affecting total FFA levels. In cortex and cerebellum, APOE4 and FAD had only minor effects on individual FFAs. The effects of APOE4 and FAD on FFA levels and FFA profiles in the three brain regions were strongly dependent of sex and age, particularly in the hippocampus. Here, most FFAs that are affected by FAD are similarly affected by APOE4. Since APOE4 and FAD affected hippocampal FFA profiles already at young age, these APOE4-induced alterations may modulate the pathogenesis of AD.

Reversal of insulin resistance in people with obesity by lifestyle-induced weight loss does not impact the proportion of circulating 12α-hydroxylated bile acids.

AIM: Bile acids (BAs) are implicated in the pathogenesis of several metabolic syndrome-related diseases, including insulin resistance (IR) and type 2 diabetes (T2D). It has been reported that IR and T2D are associated with an increased ratio of 12α/non-12α-hydroxylated BAs in the circulating BA pool. It is, however, unknown whether the improvement of insulin sensitivity inversely affects BA composition in humans. Therefore, we assessed whether lifestyle-induced weight loss induces changes in BA metabolism in people with obesity, with or without T2D, and if these changes are associated with metabolic parameters. MATERIALS AND METHODS: Individual BAs and C4 were quantified by ultra-high-performance liquid chromatography-tandem mass spectrometry in plasma samples collected from two cohorts of people with obesity (OB) and with T2D and obesity (T2D), before and after a lifestyle intervention. RESULTS: Lifestyle-induced weight loss improved glycaemic control in both cohorts, with plasma BA concentrations not affected by the lifestyle interventions. The ratio of 12α/non-12α-hydroxylated BAs remained unchanged in OB (p = .178) and even slightly increased upon intervention in T2D (p = .0147). Plasma C4 levels were unaffected in OB participants (p = .20) but significantly reduced in T2D after intervention (p = .0003). There were no significant correlations between the ratio of 12α/non-12α-hydroxylated BAs and glucose, insulin, or homeostatic model assessment-IR, nor in plasma triglycerides, low-density lipoprotein cholesterol, lipoprotein (a) in the T2D cohort. CONCLUSIONS: Lifestyle-induced weight loss did improve glycaemic control but did not affect BA concentrations. Improvements in insulin sensitivity were not associated with changes in BA parameters in people with obesity, with or without T2D.

The Effect of Sargassum fusiforme and Fucus vesiculosus on Continuous Glucose Levels in Overweight Patients with Type 2 Diabetes Mellitus: A Feasibility Randomized, Double-Blind, Placebo-Controlled Trial.

BACKGROUND: Brown seaweed is promising for the treatment of type 2 diabetes mellitus (T2DM). Its bioactive constituents can positively affect plasma glucose homeostasis in healthy humans. We investigated the effect of the brown seaweeds Sargassum (S.) fusiforme and Fucus (F.) vesiculosus in their natural form on glucose regulation in patients with T2DM. METHODS: We conducted a randomized, double-blind, placebo-controlled pilot trial. Thirty-six participants with T2DM received, on a daily basis, either 5 g of dried S. fusiforme, 5 g of dried F. vesiculosus, or 0.5 g of dried Porphyra (control) for 5 weeks, alongside regular treatment. The primary outcome was the between-group difference in the change in weekly average blood glucose levels (continuous glucose monitoring). The secondary outcomes were the changes in anthropometrics, plasma lipid levels, and dietary intake. The data were analyzed using a linear mixed-effects model. RESULTS: The change in weekly average glucose levels was 8.2 ± 2.1 to 9.0 ± 0.7 mmol/L (p = 0.2) in the S. fusiforme group (n = 12) and 10.1 ± 3.3 to 9.2 ± 0.7 mmol/L (p = 0.9) in the F. vesiculosus group (n = 10). The between-group difference was non-significant. Similarly, no between-group differences were observed for the changes in the secondary outcomes. DISCUSSION: A daily intake of 5 g of fresh, dried S. fusiforme or F. vesiculosus alongside regular treatment had no differential effect on weekly average blood glucose levels in T2DM.

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.

The effect of diet-induced weight loss on circulating homocysteine levels in people with obesity and type 2 diabetes.

BACKGROUND/AIMS: Having type 2 diabetes (T2D) in combination with being overweight results in an additional increase in cardiovascular disease (CVD) risk. In addition, T2D and obesity are associated with increased levels of total homocysteine (tHcy), possibly contributing to the CVD risk. Weight loss dieting has positive effects on several CVD risk factors, but whether it affects tHcy remains unclear. Therefore, the aim of this study was to determine the effect of a calorie restricted diet on tHcy in overweight people with T2D. METHODS: In this post-hoc analysis of the POWER study, adults with T2D and a BMI greater than 27 kg/m² were included from the outpatient diabetes clinic of the Erasmus Medical Center, Rotterdam. The patients were subjected to a very low-calorie diet with fortified meal replacements for 20 weeks. Before and after this intervention, blood samples were collected to measure tHcy and other CVD risk factors like glycaemic and lipid parameters. RESULTS: 161 overweight participants with T2D were included, with a mean age of 54 years (range 26-74), mean weight of 104.6 ± 19.9 kg and mean HbA1c of 62.7 ± 14.3 mmol/mol. At baseline, men displayed higher tHcy than women, and tHcy level was positively correlated with body weight and triglyceride levels, while it was negatively correlated with renal function and HDL cholesterol. During the intervention, bodyweight was reduced by a mean of 9.7% (from 104.6 ± 19.9 to 94.5 ± 18.1 kg p < 0.001), and all measured glycaemic and lipid blood parameters improved significantly. However, tHcy remained unchanged (from 12.1 ± 4.1 to 12.1 ± 4.2 umol/L, p = 0.880). The change in tHcy during the intervention was negatively associated with the change in weight and BMI (p = 0.01 and p = 0.008, respectively). People who lost < 10 kg (n = 92) had a mean tHcy change of -0.47 umol/L, while people who lost more than ≥ 10 kg (n = 69) had a mean tHcy change of 0.60 umol/L (p = 0.021). CONCLUSION: In conclusion, our data show that a calorie restricted diet does not affect tHcy in people with T2D and obesity, despite the use of meal replacements fortified with folic acid and vitamin B12. Our data showed a negative correlation between change in tHcy levels and weight loss, suggesting that people who lost more weight (> 10 kg) showed an increase in tHcy. Future studies should explore the potential increase in tHcy induced by weight loss dieting and target the question if tHcy reduction strategies during weight loss could be clinically beneficial.

Activation of Liver X Receptors and Peroxisome Proliferator-Activated Receptors by Lipid Extracts of Brown Seaweeds: A Potential Application in Alzheimer's Disease?

The nuclear liver X receptors (LXRα/ß) and peroxisome proliferator-activated receptors (PPARα/γ) are involved in the regulation of multiple biological processes, including lipid metabolism and inflammation. The activation of these receptors has been found to have neuroprotective effects, making them interesting therapeutic targets for neurodegenerative disorders such as Alzheimer's Disease (AD). The Asian brown seaweed Sargassum fusiforme contains both LXR-activating (oxy)phytosterols and PPAR-activating fatty acids. We have previously shown that dietary supplementation with lipid extracts of Sargassum fusiforme prevents disease progression in a mouse model of AD, without inducing adverse effects associated with synthetic pan-LXR agonists. We now determined the LXRα/ß- and PPARα/γ-activating capacity of lipid extracts of six European brown seaweed species (Alaria esculenta, Ascophyllum nodosum, Fucus vesiculosus, Himanthalia elongata, Saccharina latissima, and Sargassum muticum) and the Asian seaweed Sargassum fusiforme using a dual luciferase reporter assay. We analyzed the sterol and fatty acid profiles of the extracts by GC-MS and UPLC MS/MS, respectively, and determined their effects on the expression of LXR and PPAR target genes in several cell lines using quantitative PCR. All extracts were found to activate LXRs, with the Himanthalia elongata extract showing the most pronounced efficacy, comparable to Sargassum fusiforme, for LXR activation and transcriptional regulation of LXR-target genes. Extracts of Alaria esculenta, Fucus vesiculosus, and Saccharina latissima showed the highest capacity to activate PPARα, while extracts of Alaria esculenta, Ascophyllum nodosum, Fucus vesiculosus, and Sargassum muticum showed the highest capacity to activate PPARγ, comparable to Sargassum fusiforme extract. In CCF-STTG1 astrocytoma cells, all extracts induced expression of cholesterol efflux genes (ABCG1, ABCA1, and APOE) and suppressed expression of cholesterol and fatty acid synthesis genes (DHCR7, DHCR24, HMGCR and SREBF2, and SREBF1, ACACA, SCD1 and FASN, respectively). Our data show that lipophilic fractions of European brown seaweeds activate LXRs and PPARs and thereby modulate lipid metabolism. These results support the potential of brown seaweeds in the prevention and/or treatment of neurodegenerative diseases and possibly cardiometabolic and inflammatory diseases via concurrent activation of LXRs and PPARs.

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.

Sphingolipids in Cerebrospinal Fluid and Plasma Lipoproteins of APOE4 Homozygotes and Non-APOE4 Carriers with Mild Cognitive Impairment versus Subjective Cognitive Decline.

Background: Alzheimer's disease (AD) patients display alterations in cerebrospinal fluid (CSF) and plasma sphingolipids. The APOE4 genotype increases the risk of developing AD. Objective: To test the hypothesis that the APOE4 genotype affects common sphingolipids in CSF and in plasma of patients with early stages of AD. Methods: Patients homozygous for APOE4 and non-APOE4 carriers with mild cognitive impairment (MCI; n = 20 versus 20) were compared to patients with subjective cognitive decline (SCD; n = 18 versus 20). Sphingolipids in CSF and plasma lipoproteins were determined by liquid-chromatography-tandem mass spectrometry. Aß42 levels in CSF were determined by immunoassay. Results: APOE4 homozygotes displayed lower levels of sphingomyelin (SM; p = 0.042), SM(d18:1/18:0) (p = 0.026), and Aß42 (p < 0.001) in CSF than non-APOE4 carriers. CSF-Aß42 correlated with Cer(d18:1/18:0), SM(d18:1/18:0), and SM(d18:1/18:1) levels in APOE4 homozygotes (r > 0.49; p < 0.032) and with Cer(d18:1/24:1) in non-APOE4 carriers (r = 0.50; p = 0.025). CSF-Aß42 correlated positively with Cer(d18:1/24:0) in MCI (p = 0.028), but negatively in SCD patients (p = 0.019). Levels of Cer(d18:1/22:0) and long-chain SMs were inversely correlated with Mini-Mental State Examination score among MCI patients, independent of APOE4 genotype (r< -0.47; p < 0.039). Nevertheless, age and sex are stronger determinants of individual sphingolipid levels in CSF than either the APOE genotype or the cognitive state. In HDL, ratios of Cer(d18:1/18:0) and Cer(d18:1/22:0) to cholesterol were higher in APOE4 homozygotes than in non-APOE4 carriers (p = 0.048 and 0.047, respectively). Conclusion: The APOE4 genotype affects sphingolipid profiles of CSF and plasma lipoproteins already at early stages of AD. ApoE4 may contribute to the early development of AD through modulation of sphingolipid metabolism.

AMFR dysfunction causes autosomal recessive spastic paraplegia in human that is amenable to statin treatment in a preclinical model.

Hereditary spastic paraplegias (HSP) are rare, inherited neurodegenerative or neurodevelopmental disorders that mainly present with lower limb spasticity and muscle weakness due to motor neuron dysfunction. Whole genome sequencing identified bi-allelic truncating variants in AMFR, encoding a RING-H2 finger E3 ubiquitin ligase anchored at the membrane of the endoplasmic reticulum (ER), in two previously genetically unexplained HSP-affected siblings. Subsequently, international collaboration recognized additional HSP-affected individuals with similar bi-allelic truncating AMFR variants, resulting in a cohort of 20 individuals from 8 unrelated, consanguineous families. Variants segregated with a phenotype of mainly pure but also complex HSP consisting of global developmental delay, mild intellectual disability, motor dysfunction, and progressive spasticity. Patient-derived fibroblasts, neural stem cells (NSCs), and in vivo zebrafish modeling were used to investigate pathomechanisms, including initial preclinical therapy assessment. The absence of AMFR disturbs lipid homeostasis, causing lipid droplet accumulation in NSCs and patient-derived fibroblasts which is rescued upon AMFR re-expression. Electron microscopy indicates ER morphology alterations in the absence of AMFR. Similar findings are seen in amfra-/- zebrafish larvae, in addition to altered touch-evoked escape response and defects in motor neuron branching, phenocopying the HSP observed in patients. Interestingly, administration of FDA-approved statins improves touch-evoked escape response and motor neuron branching defects in amfra-/- zebrafish larvae, suggesting potential therapeutic implications. Our genetic and functional studies identify bi-allelic truncating variants in AMFR as a cause of a novel autosomal recessive HSP by altering lipid metabolism, which may potentially be therapeutically modulated using precision medicine with statins.

SMPD4 regulates mitotic nuclear envelope dynamics and its loss causes microcephaly and diabetes.

Biallelic loss-of-function variants in SMPD4 cause a rare and severe neurodevelopmental disorder with progressive congenital microcephaly and early death. SMPD4 encodes a sphingomyelinase that hydrolyses sphingomyelin into ceramide at neutral pH and can thereby affect membrane lipid homeostasis. SMPD4 localizes to the membranes of the endoplasmic reticulum and nuclear envelope and interacts with nuclear pore complexes (NPC). We refine the clinical phenotype of loss-of-function SMPD4 variants by describing five individuals from three unrelated families with longitudinal data due to prolonged survival. All individuals surviving beyond infancy developed insulin-dependent diabetes, besides presenting with a severe neurodevelopmental disorder and microcephaly, making diabetes one of the most frequent age-dependent non-cerebral abnormalities. We studied the function of SMPD4 at the cellular and organ levels. Knock-down of SMPD4 in human neural stem cells causes reduced proliferation rates and prolonged mitosis. Moreover, SMPD4 depletion results in abnormal nuclear envelope breakdown and reassembly during mitosis and decreased post-mitotic NPC insertion. Fibroblasts from affected individuals show deficient SMPD4-specific neutral sphingomyelinase activity, without changing (sub)cellular lipidome fractions, which suggests a local function of SMPD4 on the nuclear envelope. In embryonic mouse brain, knockdown of Smpd4 impairs cortical progenitor proliferation and induces premature differentiation by altering the balance between neurogenic and proliferative progenitor cell divisions. We hypothesize that, in individuals with SMPD4-related disease, nuclear envelope bending, which is needed to insert NPCs in the nuclear envelope, is impaired in the absence of SMPD4 and interferes with cerebral corticogenesis and survival of pancreatic beta cells.

Identification of Side Chain Oxidized Sterols as Novel Liver X Receptor Agonists with Therapeutic Potential in the Treatment of Cardiovascular and Neurodegenerative Diseases.

The nuclear receptors-liver X receptors (LXR α and ß) are potential therapeutic targets in cardiovascular and neurodegenerative diseases because of their key role in the regulation of lipid homeostasis and inflammatory processes. Specific oxy(phyto)sterols differentially modulate the transcriptional activity of LXRs providing opportunities to develop compounds with improved therapeutic characteristics. We isolated oxyphytosterols from Sargassum fusiforme and synthesized sidechain oxidized sterol derivatives. Five 24-oxidized sterols demonstrated a high potency for LXRα/ß activation in luciferase reporter assays and induction of LXR-target genes APOE, ABCA1 and ABCG1 involved in cellular cholesterol turnover in cultured cells: methyl 3ß-hydroxychol-5-en-24-oate (S1), methyl (3ß)-3-aldehydeoxychol-5-en-24-oate (S2), 24-ketocholesterol (S6), (3ß,22E)-3-hydroxycholesta-5,22-dien-24-one (N10) and fucosterol-24,28 epoxide (N12). These compounds induced SREBF1 but not SREBP1c-mediated lipogenic genes such as SCD1, ACACA and FASN in HepG2 cells or astrocytoma cells. Moreover, S2 and S6 enhanced cholesterol efflux from HepG2 cells. All five oxysterols induced production of the endogenous LXR agonists 24(S)-hydroxycholesterol by upregulating the CYP46A1, encoding the enzyme converting cholesterol into 24(S)-hydroxycholesterol; S1 and S6 may also act via the upregulation of desmosterol production. Thus, we identified five novel LXR-activating 24-oxidized sterols with a potential for therapeutic applications in neurodegenerative and cardiovascular diseases.

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.

Effect of evolocumab on fasting and post fat load lipids and lipoproteins in familial dysbetalipoproteinemia.

BACKGROUND: Familial dysbetalipoproteinemia (FD) is the second most common monogenic lipid disorder (prevalence 1 in 850-3500), characterized by postprandial remnant accumulation and associated with increased cardiovascular disease (CVD) risk. Many FD patients do not achieve non-HDL-C treatment goals, indicating the need for additional lipid-lowering treatment options. OBJECTIVES: To evaluate the effect of the PCSK9 monoclonal antibody evolocumab added to standard lipid-lowering therapy on fasting and post fat load lipids and lipoproteins in patients with FD. METHODS: A randomized placebo-controlled double-blind crossover trial comparing evolocumab (140 mg subcutaneous every 2 weeks) with placebo during two 12-week treatment periods. At the start and end of each treatment period patients received an oral fat load. The primary endpoint was the 8-hour post fat load non-HDL-C area under the curve (AUC). Secondary endpoints included fasting and post fat load lipids and lipoproteins. RESULTS: In total, 28 patients completed the study. Mean age was 62±9 years and 93% had an Ɛ2Ɛ2 genotype. Evolocumab reduced the 8-hour post fat load non-HDL-C AUC with 49% (95%CI 42-55) and apolipoprotein B (apoB) AUC with 47% (95%CI 41-53). Other fasting and absolute post fat load lipids and lipoproteins including triglycerides and remnant-cholesterol were also significantly reduced by evolocumab. However, evolocumab did not have significant effects on the rise above fasting levels that occurred after consumption of the oral fat load. CONCLUSIONS: Evolocumab added to standard lipid-lowering therapy significantly reduced fasting and absolute post fat load concentrations of non-HDL-C, apoB and other atherogenic lipids and lipoproteins in FD patients. The clinically significant decrease in lipids and lipoproteins can be expected to translate into a reduction in CVD risk in these high-risk patients.

Differential effects of bariatric surgery and lifestyle interventions on plasma levels of Lp(a) and fatty acids.

BACKGROUND: Limited evidence suggests that surgical and non-surgical obesity treatment differentially influence plasma Lipoprotein (a) [Lp(a)] levels. Further, a novel association between plasma arachidonic acid and Lp(a) has recently been shown, suggesting that fatty acids are a possible target to influence Lp(a). Here, the effects of bariatric surgery and lifestyle interventions on plasma levels of Lp(a) were compared, and it was examined whether the effects were mediated by changes in plasma fatty acid (FA) levels. METHODS: The study includes two independent trials of patients with overweight or obesity. Trial 1: Two-armed intervention study including 82 patients who underwent a 7-week low energy diet (LED), followed by Roux-en-Y gastric bypass and 52-week follow-up (surgery-group), and 77 patients who underwent a 59-week energy restricted diet- and exercise-program (lifestyle-group). Trial 2: A clinical study including 134 patients who underwent a 20-week very-LED/LED (lifestyle-cohort). RESULTS: In the surgery-group, Lp(a) levels [median (interquartile range)] tended to increase in the pre-surgical LED-phase [17(7-68)-21(7-81)nmol/L, P = 0.05], but decreased by 48% after surgery [21(7-81)-11(7-56)nmol/L, P < 0.001]. In the lifestyle-group and lifestyle-cohort, Lp(a) increased by 36%[14(7-77)-19(7-94)nmol/L, P < 0.001] and 14%[50(14-160)-57(19-208)nmol/L, P < 0.001], respectively. Changes in Lp(a) were independent of weight loss. Plasma levels of total saturated FAs remained unchanged after surgery, but decreased after lifestyle interventions. Arachidonic acid and total n-3 FAs decreased after surgery, but increased after lifestyle interventions. Plasma FAs did not mediate the effects on Lp(a). CONCLUSION: Bariatric surgery reduced, whereas lifestyle interventions increased plasma Lp(a), independent of weight loss. The interventions differentially influenced changes in plasma FAs, but these changes did not mediate changes in Lp(a). TRIAL REGISTRATION: Trial 1: Clinicaltrials.gov NCT00626964. Trial 2: Netherlands Trial Register NL2140 (NTR2264).

The ApoA-I mimetic peptide 5A enhances remyelination by promoting clearance and degradation of myelin debris.

The progressive nature of demyelinating diseases lies in the inability of the central nervous system (CNS) to induce proper remyelination. Recently, we and others demonstrated that a dysregulated innate immune response partially underlies failure of CNS remyelination. Extensive accumulation of myelin-derived lipids and an inability to process these lipids was found to induce a disease-promoting phagocyte phenotype. Hence, restoring the ability of these phagocytes to metabolize and efflux myelin-derived lipids represents a promising strategy to promote remyelination. Here, we show that ApoA-I mimetic peptide 5A, a molecule well known to promote activity of the lipid efflux transporter ABCA1, markedly enhances remyelination. Mechanistically, we find that the repair-inducing properties of 5A are attributable to increased clearance and metabolism of remyelination-inhibiting myelin debris via the fatty acid translocase protein CD36, which is transcriptionally controlled by the ABCA1-JAK2-STAT3 signaling pathway. Altogether, our findings indicate that 5A promotes remyelination by stimulating clearance and degradation of myelin debris.

Establishing the relationship between familial dysbetalipoproteinemia and genetic variants in the APOE gene.

Familial Dysbetalipoproteinemia (FD) is the second most common monogenic dyslipidemia and is associated with a very high cardiovascular risk due to cholesterol-enriched remnant lipoproteins. FD is usually caused by a recessively inherited variant in the APOE gene (ε2ε2), but variants with dominant inheritance have also been described. The typical dysbetalipoproteinemia phenotype has a delayed onset and requires a metabolic hit. Therefore, the diagnosis of FD should be made by demonstrating both the genotype and dysbetalipoproteinemia phenotype. Next Generation Sequencing is becoming more widely available and can reveal variants in the APOE gene for which the relation with FD is unknown or uncertain. In this article, two approaches are presented to ascertain the relationship of a new variant in the APOE gene with FD. The comprehensive approach consists of determining the pathogenicity of the variant and its causal relationship with FD by confirming a dysbetalipoproteinemia phenotype, and performing in vitro functional tests and, optionally, in vivo postprandial clearance studies. When this is not feasible, a second, pragmatic approach within reach of clinical practice can be followed for individual patients to make decisions on treatment, follow-up, and family counseling.

Maternal lipid levels in early pregnancy as a predictor of childhood lipid levels: a prospective cohort study.

BACKGROUND: Maternal lipid levels in early pregnancy are associated with maternal health and foetal growth. It is however unclear if maternal lipids in early pregnancy can be used to predict childhood lipid levels. The aim of this study is to assess the association between maternal and offspring childhood lipid levels, and to investigate the influence of maternal BMI and diet on these associations. METHODS: This study included 2692 women participating in the Generation R study, an ongoing population-based prospective cohort study from early life onwards. Women with an expected delivery date between 2002 and 2006 living in Rotterdam, the Netherlands were included. Total cholesterol, triglycerides and high-density lipoprotein cholesterol (HDL-c) were measured in early pregnancy (median 13.2 weeks [90% range 10.6; 17.1]). Low-density lipoprotein cholesterol (LDL-c), remnant cholesterol and non-HDL-c were calculated. Corresponding lipid measurements were determined in 2692 children at the age of 6 (median 6.0 years [90% range 5.7; 7.5]) and 1673 children 10 years (median 9.7 years [90% range 9.5; 10.3]). Multivariate linear regression analysis was used to examine the association between maternal lipid levels in early pregnancy and the corresponding childhood lipid measurements at the ages of 6 and 10 years while adjusting for confounders. RESULTS: Maternal lipid levels in early pregnancy are positively associated with corresponding childhood lipid levels 6 and 10 years after pregnancy, independent of maternal body mass index and diet. CONCLUSIONS: Maternal lipid levels in early pregnancy may provide an insight to the lipid profile of children years later. Gestational lipid levels may therefore be used as an early predictor of children's long-term health. Monitoring of these gestational lipid levels may give a window-of-opportunity to start early interventions to decrease offspring's lipid levels and possibly diminish their cardiovascular risk later in life. Future studies are warranted to investigate the genetic contribution on maternal lipid levels in pregnancy and lipid levels of their offspring years later.

FTY720 decreases ceramides levels in the brain and prevents memory impairments in a mouse model of familial Alzheimer's disease expressing APOE4.

The protection mediated by the bioactive sphingolipid sphingosine-1-phosphate (S1P) declines during Alzheimer's disease (AD) progression, especially in patients carrying the apolipoprotein E ε4 (APOE4) isoform. The drug FTY720 mimics S1P bioactivity, but its efficacy in treating AD is unclear. Two doses of FTY720 (0.1 mg / kg and 0.5 mg / kg daily) were given by oral gavage for 15 weeks to transgenic mouse models of familial AD carrying human apolipoprotein E (APOE) APOE3 (E3FAD) or APOE4 (E4FAD). After 12 weeks of treatment, animals were subjected to behavioral tests for memory, locomotion, and anxiety. Blood was withdrawn at different time points and brains were collected for sphingolipids analysis by mass spectrometry, gene expression by RT-PCR and Aß quantification by ELISA. We discovered that low levels of S1P in the plasma is associated with a higher probability of failing the memory test and that FTY720 prevents memory impairments in E4FAD. The beneficial effect of FTY720 was induced by a shift of the sphingolipid metabolism in the brain towards a lower production of toxic metabolites, like ceramide d18:1/16:0 and d18:1/22:0, and reduction of amyloid-ß burden and inflammation. In conclusion, we provide further evidence of the druggability of the sphingolipid system in AD.

Comprehensive (apo)lipoprotein profiling in patients with genetic hypertriglyceridemia using LC-MS and NMR spectroscopy.

BACKGROUND: Mutations in genes encoding lipoprotein lipase (LPL) or its regulators can cause severe hypertriglyceridemia (HTG). Thus far, the effect of genetic HTG on the lipid profile has been mainly determined via conventional techniques. OBJECTIVE: To show detailed differences in the (apo)lipoprotein profile of patients with genetic HTG by combining LC-MS and NMR techniques. METHODS: Fasted serum from 7 patients with genetic HTG and 10 normolipidemic controls was used to measure the concentration of a spectrum of apolipoproteins by LC-MS, and to estimate the concentration and size of lipoprotein subclasses and class-specific lipid composition using NMR spectroscopy. RESULTS: Patients with genetic HTG compared to normolipidemic controls had higher levels of apoB48 (fold change [FC] 11.3, P<0.001), apoC-I (FC 1.5, P<0.001), apoC-II (FC 4.3, P=0.007), apoC-III (FC 3.4, P<0.001), and apoE (FC 4.3, P<0.001), without altered apoB100. In addition, patients with genetic HTG had higher concentrations of TG-rich lipoproteins (i.e., chylomicrons and very low-density lipoproteins [VLDL]; FC 3.0, P<0.001), but lower LDL (FC 0.4, P=0.001), of which medium and small-sized LDL particles appeared even absent. While the correlation coefficient between NMR and enzymatic analysis in normolipidemic controls was high, it was considerably reduced in patients with genetic HTG. CONCLUSION: The lipoprotein profile of patients with genetic HTG is predominated with large lipoproteins (i.e., chylomicrons, VLDL), explaining high levels of apoC-I, apoC-II, apoC-III and apoE, whereas small atherogenic LDL particles are absent. The presence of chylomicrons in patients with HTG weakens the accuracy of the NMR-based model as it was designed for normolipidemic fasted individuals.

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.