Plasma Plant Sterol Research Articles

Cardiovascular Safety of Plant Sterol and Stanol Consumption.

Plant sterols and stanols as components of functional foods are widely used for cholesterol lowering. The regular intake of these functional foods is associated with a decrease in low density lipoprotein cholesterol of about 10 % and an increase in plasma plant sterol or stanol concentrations by about a factor of 2. There is no doubt that a decrease in low density lipoprotein cholesterol is beneficial to cardiovascular health. However, due to the concomitant increase in circulating plant sterols safety issues associated with the intake of plant sterol containing functional foods have been raised. Herein, we will review and evaluate those arguments raised against the use of plant sterols and stanols.

The effect of a low-fat spread with added plant sterols on vascular function markers: results of the Investigating Vascular Function Effects of Plant Sterols (INVEST) study

Background: Plant sterols (PSs) lower LDL cholesterol, an established risk factor for coronary artery disease (CAD). No direct evidence is available supporting a reduced risk of CAD for foods with added PSs. Endothelial dysfunction is seen as an early indicator of atherosclerotic damage.Objectives: This study was primarily designed to investigate the effect of a low-fat spread with added PSs on brachial artery endothelial function as measured by flow-mediated dilation (FMD). Second, effects on arterial stiffness, blood pressure, serum lipids, and plasma PS concentrations were investigated. We hypothesized that PSs would not worsen FMD but would rather modestly improve FMD.Design: This study had a double-blind, randomized, placebo-controlled, parallel design. After a 4-wk run-in period, 240 hypercholesterolemic but otherwise healthy men and women consumed 20 g/d of low-fat spread without (control) or with added PSs (3 g/d) during 12 wk. Pre- and postintervention, vascular function measurements and blood sampling were performed.Results: In total, 232 participants completed the study period. For the primary endpoint FMD, 199 participants were included in the statistical analysis. PS intake did not affect FMD (+0.01 percentage points; 95% CI: −0.73, 0.75) compared with control. Measures of arterial stiffness (pulse wave velocity and augmentation index) and blood pressure were also not significantly changed compared with control. After PS intervention, LDL cholesterol significantly decreased on average by 0.26 mmol/L (95% CI: −0.40, −0.12) or 6.7% compared with control. Plasma sitosterol and campesterol concentrations significantly increased in the PS group up to on average 11.5 μmol/L and 13.9 μmol/L (expressed as geometric means), respectively.Conclusions: The intake of a low-fat spread with added PSs neither improved nor worsened FMD or other vascular function markers in hypercholesterolemic men and women. As expected, serum LDL cholesterol decreased, whereas plasma PSs increased after PS intake. This study was registered at clinicaltrials.gov as NCT01803178.

Potential risks associated with increased plasma plant-sterol levels

The consumption of plant sterols is associated with a decrease in LDL cholesterol. However, it is also associated with an increase in plasma plant-sterol (sitosterol, campesterol) levels that may be detrimental. Indeed, the genetic disease sitosterolaemia, which is characterized by elevated plasma levels of plant sterol, is associated with premature atherosclerosis. Yet, although plasma plant-sterol levels are recognized markers of cholesterol absorption, the relationship between such levels and atherosclerosis is not clear. Several studies have analysed the association between plasma plant-sterol levels and cardiovascular disease (CVD), but have found conflicting results. Although the largest prospective trials and genome-wide association studies suggest that high plasma levels of plant sterols are associated with increased CV risk, other studies have reported no such association and even an inverse relationship. Thus, the available data cannot confirm an increased CV risk with plant sterols, but cannot rule it out either. Only a prospective interventional trial to analyse the effects of plant-sterol-enriched food on the occurrence of CV events can exclude a potential CV risk linked with their consumption.

Consumption of a dietary portfolio of cholesterol lowering foods improves blood lipids without affecting concentrations of fat soluble compounds

BackgroundConsumption of a cholesterol lowering dietary portfolio including plant sterols (PS), viscous fibre, soy proteins and nuts for 6 months improves blood lipid profile. Plant sterols reduce blood cholesterol by inhibiting intestinal cholesterol absorption and concerns have been raised whether PS consumption reduces fat soluble vitamin absorption.ObjectiveThe objective was to determine effects of consumption of a cholesterol lowering dietary portfolio on circulating concentrations of PS and fat soluble vitamins.MethodsUsing a parallel design study, 351 hyperlipidemic participants from 4 centres across Canada were randomized to 1 of 3 groups. Participants followed dietary advice with control or portfolio diet. Participants on routine and intensive portfolio involved 2 and 7 clinic visits, respectively, over 6 months.ResultsNo changes in plasma concentrations of α and γ tocopherol, lutein, lycopene and retinol, but decreased β-carotene concentrations were observed with intensive (week 12:p = 0.045; week 24:p = 0.039) and routine (week 12:p = 0.031; week 24:p = 0.078) portfolio groups compared to control. However, cholesterol adjusted β-carotene and fat soluble compound concentrations were not different compared to control. Plasma PS concentrations were increased with intensive (campesterol:p = 0.012; β-sitosterol:p = 0.035) and routine (campesterol: p = 0.034; β-sitosterol: p = 0.080) portfolio groups compared to control. Plasma cholesterol-adjusted campesterol and β-sitosterol concentrations were negatively correlated (p < 0.001) with total and LDL-C levels.ConclusionResults demonstrate that consuming a portfolio diet reduces serum total and LDL-C levels while increasing PS values, without altering fat soluble compounds concentrations. The extent of increments of PS with the current study are not deleterious and also maintaining optimum levels of fat soluble vitamins are of paramount necessity to maintain overall metabolism and health. Results indicate portfolio diet as one of the best options for CVD risk reduction.Trial registrationclinicaltrials.gov Identifier: NCT00438425

Ezetimibe Reduces Plant Sterol Accumulation and Favorably Increases Platelet Count in Sitosterolemia

To assess if ezetimibe (EZE), a sterol-absorption inhibitor, improves platelet (PLT) count and size relative to its effect on plasma plant sterol (PS) in patients with sitosterolemia (STSL). Patients with STSL (5 males, 3 females, 16-56 years of age) receiving EZE intervention as part of their routine care participated in this study. EZE was discontinued for 14 weeks (off) and then resumed for another 14 weeks (on). Hematology variables along with plasma and red blood cells (RBC) PS and total cholesterol (TC) levels were measured at the end of each phase. EZE increased PLT count (23% ± 9%) and decreased mean PLT volume (MPV; 10% ± 3%, all P < .05). In patients off EZE, PLT counts inversely correlated (r = -0.96 and r = -0.91, all P < .01) with plasma and RBC PS to TC ratio (PS/TC), and MPV positively correlated (r = 0.91, P = .03 and r = 0.93, P = .02) with plasma and RBC PS/TC. EZE reduced plasma and RBC sitosterol (-35% ± 4% and -28% ± 3%), total PS (-37% ± 4% and -28% ± 3%, all P < .0001) levels, and PS/TC (-27% ± 4% and -28% ± 4%, P < .01). EZE reduces plasma and RBC PS levels, while increasing PLT count and decreasing MPV, and thereby may reduce the risk for bleeding in STSL. Plasma PS levels and ABCG5/ABCG8 genes should be analyzed in patients with unexplained hematologic abnormalities.

Sitosterolemia: diagnosis, investigation, and management.

Sitosterolemia is a rare autosomal recessively inherited disease caused by mutations affecting ABCG5 or ABCG8, which are located on human chromosome band 2p21. Around 100 cases have been reported in the literature. Sitosterolemic patients typically exhibit a 30-fold to 100-fold increase in plasma concentrations of plant sterols. The clinical manifestations include xanthomas, premature atherosclerosis, hemolytic anemia, and macrothrombocytopenia. It is noteworthy that abnormal hematological parameters may be the only clinical feature of sitosterolemic patients, suggesting that sitosterolemia may be more frequent than previously thought. Severe accumulation of plant sterols in mouse models of sitosterolemia induced complex cardiac lesions, anemia, and macrothrombocytopenia, disrupted adrenal and liver cholesterol homeostasis, and caused infertility and hypertriglyceridemia. It remains unclear whether all disease traits are present in sitosterolemic patients. The drug ezetimibe appears to be effective in reducing plasma plant sterol levels, promotes xanthoma regression, and improves the cardiovascular and hematological signs in sitosterolemic patients.

Premature atherosclerosis is not systematic in phytosterolemic patients: Severe hypercholesterolemia as a confounding factor in five subjects

ObjectivePhytosterolemia is a rare autosomal recessive disorder characterized by dramatically elevated circulating levels of plant sterols (PS). Phytosterolemia is believed to be responsible for severe premature atherosclerosis. The clinical, biological and molecular genetic features of 5 patients with phytosterolemia and transient severe hypercholesterolemia challenge this hypothesis. MethodsOur patients were referred for suspected homozygous familial hypercholesterolemia. Despite the phenotype, this diagnosis was invalidated and phytosterolemia was confirmed by the identification of mutations in the ABCG5/ABCG8 transporter complex. Plasma PS were analyzed with a mass spectrometric-gas chromatographic procedure. Vascular status was assessed with carotid ultrasonography and completed (for 4 of the 5 patients) with femoral ultrasonography; additional examinations of cardiovascular status included a stress test, determination of coronary calcium score, echocardiography, non-invasive assessment of endothelium-dependent dilatation and coronarography. ResultsThe 5 patients displayed markedly elevated levels of both β-sitosterol and campesterol (15–30 fold higher than normal values). However, none displayed significant signs of infraclinical premature atherosclerosis (respectively at the ages of 32, 27, 29, 11 and 11 years). All patients were characterized by very high levels of total (>450 mg/dl) and LDL-cholesterol (>350 mg/dl) at diagnosis which decreased markedly on dietary intervention alone. Treatment with cholestyramine or Ezetimibe ± atorvastatin normalized cholesterol levels, although plasma PS concentrations remained elevated. ConclusionThe clinical and biological characteristics of our patients, considered together with reports of cases which equally lack CVD, support the contention that the premature atherosclerosis associated with phytosterolemia in some patients may be due at least in part to mechanisms independent of elevated circulating phytosterol levels.

Specific macrothrombocytopenia/hemolytic anemia associated with sitosterolemia

Sitosterolemia (phytosterolemia) is a rare inherited sterol storage disorder, characterized by significantly elevated plasma levels of plant sterols. The clinical features of sitosterolemia are xanthomas, premature atherosclerosis, arthritis, and, occasionally, liver function impair and hematologic abnormalities. This disorder is caused by mutations of ABCG5/ABCG8 genes. We report here the clinical, laboratory, and molecular genetic features of 13 patients with sitosterolemia from eight unrelated families who had specific hematologic problems of macrothrombocytopenia, hemolytic anemia, and splenomegaly besides the major clinical manifestations. The peripheral blood films showed some unique features: large platelets surrounded by a circle of vacuoles, and various abnormal erythrocyte shapes, especially stomatocyte. According to these distinct changes of blood cell morphology, we identified two sitosterolemia patients who lacked the classical clinical phenomena. All the patients had been misdiagnosed with immune thrombocytopenia (ITP), Evans syndrome, or secondary ITP with delay being 28.8 years between symptom onset and correct diagnosis. These results indicate that sitosterolemia is certainly not as rare as originally thought. The phenomena of macrothrombocytopenia/hemolysis might represent a new platelet disorder. Plasma plant sterols and ABCG5/ABCG8 genes should be analyzed when such hematologic abnormalities are unexplained.

Scavenger receptor BI and ABCG5/G8 differentially impact biliary sterol secretion and reverse cholesterol transport in mice

Biliary lipid secretion plays an important role in gallstone disease and reverse cholesterol transport (RCT). Using Sr-bI/Abcg5 double knockout mice (dko), the present study investigated the differential contribution of two of the most relevant transporters: adenosine triphosphate (ATP)-binding cassette subfamily G member 5 and 8 (ABCG5/G8) and scavenger receptor class B type I (SR-BI) to sterol metabolism and RCT. Plasma cholesterol levels increased in the following order, mainly due to differences in high density lipoprotein (HDL): Abcg5 ko < wild type < Sr-bI/Abcg5 dko < Sr-bI ko. Liver cholesterol content was elevated in Sr-bI ko only (P < 0.05). In Sr-bI/Abcg5 dko plasma plant sterols were highest, while hepatic plant sterols were lower compared with Abcg5 ko (P < 0.05). Under baseline conditions, biliary cholesterol secretion rates decreased in the following order: wild type > Sr-bI ko (-16%) > Abcg5 ko (-75%) > Sr-bI/Abcg5 dko (-94%), all at least P < 0.05, while biliary bile acid secretion did not differ between groups. However, under supraphysiological conditions, upon infusion with increasing amounts of the bile salt tauroursodeoxycholic acid, Abcg5 became fully rate-limiting for biliary cholesterol secretion. Additional in vivo macrophage-to-feces RCT studies demonstrated an almost 50% decrease in overall RCT in Sr-bI/Abcg5 dko compared with Abcg5 ko mice (P < 0.01). These data demonstrate that (1) SR-BI contributes to ABCG5/G8-independent biliary cholesterol secretion under basal conditions; (2) biliary cholesterol mass secretion under maximal bile salt-stimulated conditions is fully dependent on ABCG5/G8; and (3) Sr-bI contributes to macrophage-to-feces RCT independent of Abcg5/g8.

Plasma plant sterols serve as poor markers of cholesterol absorption in man

The validation of the use of plasma plant sterols as a marker of cholesterol absorption is frail. Nevertheless, plant sterol concentrations are routinely used to describe treatment-induced changes in cholesterol absorption. Their use has also been advocated as a clinical tool to tailor cholesterol-lowering therapy. Prior to wider implementation, however, the validity of plant sterols as absorption markers needs solid evaluation. Therefore, we compared plasma plant sterol concentrations to gold-standard stable isotope-determined cholesterol absorption. Plasma campesterol/TC concentrations (camp/TC) were measured in a population of 175 mildly hypercholesterolemic individuals (age: 59.7 ± 5.6 years; BMI: 25.5 ± 2.9 kg/m(2); LDL-C: 4.01 ± 0.56 mmol/l). We compared cholesterol absorption according to the plasma dual-isotope method in subjects with the highest camp/TC concentrations (N = 41, camp/TC: 2.14 ± 0.68 μg/mg) and the lowest camp/TC concentrations (N = 39, camp/TC: 0.97 ± 0.22 μg/mg). Fractional cholesterol absorption did not differ between the groups (24 ± 12% versus 25 ± 16%, P = 0.60), nor was it associated with plasma camp/TC concentrations in the total population of 80 individuals (β = 0.13; P = 0.30, adjusted for BMI and plasma triglycerides). Our findings do not support a relation between plasma plant sterol concentrations and true cholesterol absorption and, therefore, do not favor the use of these sterols as markers of cholesterol absorption. This bears direct consequences for the interpretation of earlier studies, as well as for future studies targeting intestinal regulation of cholesterol metabolism.

L. reuteri NCIMB 30242: A Probiotic with Benefits

ObjectivesThe objective of this study was to evaluate the effects of probiotic bile salt hydrolase‐active Lactobacillus reuteri NCIMB 30242 on cholesterol lowering, mechanism of action and gastrointestinal (GI) symptomatology in hypercholesterolemic adults.Methods127 subjects consumed either L. reuteri NCIMB 30242 or placebo capsules over a 9‐week intervention period in a randomized controlled trial.ResultsL. reuteri NCIMB 30242 capsules reduced LDL‐cholesterol by 11.6% (P=0.001), total cholesterol by 9.1%, (P&lt;0.001), non‐HDL‐cholesterol by 11.3% (P&lt;0.001), apoB‐100 by 8.4% (P=0.002) and cholesteryl ester saturated fatty acids by 8.8% (P=0.002) relative to placebo over the intervention period. Treated subjects showed a significant increase in plasma deconjugated bile acids (P&lt;0.05), indicating increased intraluminal deconjugation, and a significant decrease in plasma plant sterols (P&lt;0.05). hs‐CRP was reduced by 1.05 mg/l (P=0.005) in treated subjects relative to placebo with changes positively correlated to interleukin‐6 and tumor necrosis factor‐α. Further, a higher proportion of treated subjects reported improved symptoms for diagnosis of irritable bowel syndrome and unspecified functional bowel disorders (P&lt;0.05).ConclusionsL. reuteri NCIMB 30242 capsules should be considered as an adjunctive therapy for hypercholesterolemia and may be useful for promoting GI health.

Effects of plant sterol- or stanol-enriched margarine on fasting plasma oxyphytosterol concentrations in healthy subjects

BackgroundConsumption of plant sterols and plant stanols reduces low-density lipoprotein cholesterol (LDL-C) concentrations. At the same time, plasma plant sterol concentrations will increase after plant sterol consumption, but decrease after plant stanol consumption. In contrast to plant stanols, plant sterols can undergo oxidation and form oxyphytosterols. Findings from in vitro and animal studies suggest that oxyphytosterols might be atherogenic. ObjectiveThe objective was to examine whether plant sterol and stanol consumption changes fasting plasma oxyphytosterol concentrations. DesignA randomized, double blind, cross-over study was performed in which 43 healthy subjects (18–70 years) consumed for 4 weeks a plant sterol-enriched (3.0 g/d of plant sterols), a plant stanol-enriched (3.0 g/d of plant stanols), and a control margarine separated by wash-out periods of 4 weeks. Oxyphytosterol concentrations were determined in BHT-enriched plasma via GC–MS. ResultsCompared to control, serum LDL-C concentrations were reduced after plant sterol (−8.1%; p < 0.001) and plant stanol consumption (−7.8%; p < 0.001). Plant sterol consumption did not change plasma oxyphytosterol concentrations. On the other hand, intake of the plant stanol margarine reduced 7β-OH-campesterol by 0.07 ng/mL (∼14%; p < 0.01) and by 0.07 ng/mL (∼15%; p < 0.01) compared with the control and sterol margarines, respectively. When standardized for serum cholesterol, effects on these oxyphytosterols were comparable. In addition, plant stanol intake reduced cholesterol-standardized 7-keto-campesterol levels compared with plant sterol intake (p < 0.05). ConclusionsDaily consumption of a plant sterol-enriched margarine does not increase oxyphytosterol concentrations, while plant stanol consumption may reduce the concentrations of the oxidative plant sterol metabolites 7β-OH-campesterol and 7-keto-campesterol. This trial is registered at clinicaltrials.gov as NCT01559428.

The ABCG8 G574R Variant, Serum Plant Sterol Levels, and Cardiovascular Disease Risk in the Old Order Amish

To determine whether long-term exposure to moderate elevations in plasma plant sterol levels increases risk for atherosclerosis. In Old Order Amish participants aged 18 to 85 years, with (n=110) and without (n=181) 1 copy of the ABCG8 G574R variant, we compared mean plasma levels of plant sterols and cholesterol precursors and carotid intima-media wall thickness. Carriers of a single 574R allele had increased plant sterol levels (eg, 35%-37% higher plasma levels of sitosterol, campesterol, and stigmasterol) and increased plant sterol/cholesterol ratios (P<0.001 for all). 574R carriers had significantly decreased levels of lathosterol and lanosterol, precursors in a pathway for endogenous cholesterol synthesis, suggesting that plant sterols may alter regulation of genes involved in cholesterol synthesis. The G574R variant was not associated with high-density lipoprotein cholesterol or low-density lipoprotein cholesterol levels. Compared with noncarriers, 574R carriers had decreased carotid intima-media wall thickness (0.62 versus 0.66 mm; age- and sex-adjusted P=0.03). Adjustment for body weight, blood pressure, and standard lipid measures (high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides) did not alter this association. Although the G574R variant is associated with moderately elevated plant sterol levels, carriers of the 574R allele had modestly lower levels of carotid wall thickness compared with noncarriers.

Sitosterolaemia: role of different pathology disciplines in its diagnosis and management

Introduction Sitosterolaemia is a rare autosomal recessive disorder caused by mutations of ABCG5 and ABCG8, which leads to progressive accumulation of plant sterols within the body. We describe a patient with sitosterolaemia who presented with stoma-tocytosis and macrothrombocytopenia. Case report A pre-operative full blood count was checked on a 30-year-old Turkish woman (from parents as first degree cousin) with known history of idiopathic thrombocytopenia. Review of this blood film together with those from the past 2 years revealed a persistent picture of stomatocytosis and macrothrombocytopenia. Literature suggests these features can be from sitosterolaemia. There was history of migraine, oral contraceptive pill related acute hepatocellular hepatitis and hyperlipidaemia (total cholesterol 6.1 mmol/L, LDL-C 4.0 mmol/L, triglyceride 0.9 mmol/L - not on OC pills). There was no history of statin therapy and no family history of sitosterolaemia or premature cardiovascular diseases. Examination only revealed bilateral xanthelasma. Results Total plasma plant sterol was markedly raised (1.3 mmol/ L; NR Conclusions Sitosterolaemia can present exclusively with stoma-tocytosis and macrothrombocytopenia.1 Whether they represent a subgroup with a different prognosis is unknown.

Increased plasma plant sterol concentrations and a heterozygous amino acid exchange in ATP binding cassette transporter ABCG5: A case report

Whilst conducting a scientific study, an elevated plasma plant sterol concentration of 3.07 mg/dL was established in one proband. Similar levels found in his mothers plasma (2.73 mg/dL) were suggestive of a heterozygous sitosterolemia. The resulting gene analysis for ATP binding cassette transporter G5/G8 (ABCG5/G8) revealed a heterozygous polymorphism in ABCG8 (Thr400Lys, rs4148217), which the proband had inherited from his father. However, a heterozygous amino acid exchange (Arg406Gln) in exon 9 of ABCG5 was revealed, which was inherited from his mother. Although not sufficient evidence exists to regard this sequence variation as a mutation, this previously unreleased sequence variation occurred in a “hot spot” area for sitosterolemia of the ABCG5 gene (exon 9) and the similar increased plasma plant sterol concentrations of the heterozygous mother contribute to the notion, that this very likely presents an inactivating mutation.

Role of plant sterols in lipid lowering--a safety issue

Sir, In their review Gupta et al .1 failed to emphasize enough the crucial difference between plant sterols and stanols, namely their contrasting effects on plasma levels of plant sterols. Consumption of plant sterol esters raises plasma plant sterols whereas plant stanol esters lower them, by blocking their absorption. Evidence for this differential effect of plant sterols and stanols is derived both from population studies2 and clinical trials. In the latter, serum plant sterol levels increased by 35–120% on consumption of plant sterol 1.6 g daily,3 whereas taking 1.6 g of plant stanol …

Macrothrombocytopenia and Hemolysis Associated with Phytosterolemia

AbstractAbstract 2515 Objective:Phytosterolemia is a rare autosomal recessive sterol storage disease, characterized by increased serum concentrations of plant sterols (phytosterols). It is caused by gene mutations of ABCG5 and ABCG8. The patients suffer from xanthomas and premature atherosclerosis. In this study we demonstrate that macrothrombocytopenia and hemolysis are intrinsic features in four unrelated patients with phytosterolemia, and their clinical and pathogenesis are investigated. Methods:Erythrocyte and platelet morphology was examined under light microscope. Platelet aggregation was measured turbidometrically. Platelet glycoproteins were analyzed using flow cytometry. Biochemistry was analyzed by routine methods. The plasma sterol levels were measured by HPLC method. ABCG5 and ABCG8 genes were directly sequenced to identify mutations, Restriction endonuclease analysis was used to exclude the possibility of gene polymorphism. Result:All the four patients presented xanthomas, macrothrombocytopenia, hemolysis and splenomegaly. The blood smears showed large platelets, some as large as erythrocytes and abnormal erythrocyte shapes, such as stomatocytes. All the patients had bleeding tendency. There were mild defect in aggregation induced by ADP and ristocetin. The red cells showed an increased osmotic fragility. Plasma concentrations of phytosterols including sitosterol, stigmasterol and cholestanol were markedly elevated (30 fold) in the affected patients. Patient 1 was found to be homozygous for C→T mutation at nucleotide 64 in exon 1 of the ABCG5 gene, which results in the premature termination of the ABCG5 protein at amino acid 22 (Gln22X). Patient 2 was homozygous for C→T mutation at nucleotide 1336 in exon 10 of the ABCG5 gene, which results in the premature termination of the ABCG5 protein at amino acid 446 (Arg446X). Patient 3 was compound heterozygous for a large fragment deletion at nucleotide 1842 to 1883 in exon 12, and a complex mutation of del 1938C–1939G/ins1938T in exon 13 of ABCG8. Patient 4 was also compound heterozygous for C→T mutation at nucleotide 1336 in exon 10 and A→G mutation at classical cut locus in intron 9. Conclusion:In this study, we identified four patients with phytosterolemia who had macrothrombocytopenia and stomatocytic hemolysis in addition to common increased plasma plant sterols and xanthomas. Gene analysis confirmed the diagnosis. We suggest that the coexisting macrothrombocytopenia and stomatocytic hemolysis represent a new subtype of phytosterolemia, and plasma phytosterols should be measured in patients who have stomatocytic hemolysis and macrothrombocytopenia (so called“Mediteranean macrothrombocytopenia/ stomatocytosis”). Disclosures:No relevant conflicts of interest to declare.

Impact of atorvastatin and omega-3 ethyl esters 90 on plasma plant sterol concentrations and cholesterol synthesis in type 2 diabetes: A randomised placebo controlled factorial trial

Objective To determine the effects of statin treatment and omega-3 polyunsaturated fatty acid supplementation on plasma plant sterol concentrations and cholesterol synthesis in patients with type 2 diabetes. Methods Plant sterol concentrations and lanosterol (a marker of cholesterol synthesis) were measured using a high sensitivity assay to assess the effect of double-blind daily treatment for 4 months with atorvastatin 20 mg or placebo and, in a 2 × 2 factorial design, omega-3 ethyl esters 90 2 g or placebo. Results 658 patients were included in a per protocol analysis. The 4 treatment groups had similar mean [SD] age (63.5 years [11.7]), HbA 1c (6.9% [1.1]) and diabetes duration (median 4 years [inter-quartile range 2, 8]). Atorvastatin treatment alone reduced low density lipoprotein (LDL) cholesterol by 1.4 mmol/l (44%, p < 0.001), triglycerides by 0.3 mmol/l (20%, p < 0.0001) and lanosterol by 0.36 μmol/l (72%, p < 0.001). There was no significant placebo adjusted change in median [95% confidence intervals] total plant sterol concentrations (−0.77 μmol/l [inter-quartile range −2.13, 0.59]), although they were increased significantly with omega-3-acid EE90 treatment (3.23 μmol/l [1.28, 5.17]). There was a 27% smaller reduction in LDL cholesterol with atorvastatin treatment in low cholesterol synthesisers with high absorption, defined by changes at or above the median lanosterol and campesterol levels, respectively, compared with the obverse group (difference 0.42 mmol/l [0.21, 0.62]). Conclusion Treatment with atorvastatin in type 2 diabetes did not change median total plasma plant sterol concentrations, but LDL cholesterol was reduced most efficaciously in high cholesterol synthesisers with low intestinal cholesterol absorption. Clinical trial registration information Current controlled trials number ISRCTN: 76737502 ( http://isrctn.org).

The associations of cholesterol metabolism and plasma plant sterols with all-cause and cardiovascular mortality

Moderately elevated levels of plasma plant sterols have been suspected to be causally involved in atherosclerosis. The aim of this study was to investigate whether plant sterols and other markers of sterol metabolism predicted all-cause and cardiovascular mortality in participants of the Ludwigshafen Risk and Cardiovascular health (LURIC) study. A total of 1,257 individuals who did not use statins and at baseline had a mean (+/- SD) age of 62.8 (+/- 11.0) years were included in the present analysis. Lathosterol, cholestanol, campesterol, and sitosterol were measured to estimate cholesterol synthesis and absorption. The mean (+/- SD) time of the follow-up for all-cause and cardiovascular mortality was 7.32 (+/- 2.3) years. All-cause (P = 0.001) and cardiovascular (P = 0.006) mortality were decreased in the highest versus the lowest lathosterol to cholesterol tertile. In contrast, subjects in the third cholestanol to cholesterol tertile had increased all-cause (P < 0.001) and cardiovascular mortality (P = 0.010) compared with individuals in the first tertile. The third campesterol to cholesterol tertile was associated with increased all-cause mortality (P = 0.025). Sitosterol to cholesterol tertiles were not significantly related to all-cause or cardiovascular mortality. The data suggest that high absorption and low synthesis of cholesterol predict increased all-cause and cardiovascular mortality in LURIC participants.

Systematic haplotype analysis resolves a complex plasma plant sterol locus on the Micronesian Island of Kosrae

Pinpointing culprit causal variants along signal peaks of genome-wide association studies (GWAS) is challenging. To overcome confounding effects of multiple independent variants at such a locus and narrow the interval for causal allele capture, we developed an approach that maps local shared haplotypes harboring a putative causal variant. We demonstrate our method in an extreme isolate founder population, the pacific Island of Kosrae. We analyzed plasma plant sterol (PPS) levels, a surrogate measure of cholesterol absorption from the intestine, where previous studies have implicated 2p21 mutations in the ATP binding cassette subfamily G members 5 or 8 (ABCG5 or ABCG8) genes. We have previously reported that 11.1% of the islanders are carriers of a frameshift ABCG8 mutation increasing PPS levels in carriers by 50%. GWAS adjusted for this mutation revealed genomewide significant signals along 11 Mb around it. To fine-map this signal, we detected pairwise identity-by-descent haplotypes using our tool GERMLINE and implemented a clustering algorithm to identify haplotypes shared across multiple samples with their unique shared boundaries. A single 526-kb haplotype mapped strongly to PPS levels, dramatically refining the mapped interval. This haplotype spans the ABCG5/ABCG8 genes, is carried by 1.8% of the islanders, and results in a striking 100% increase of PPS in carriers. Resequencing of ABCG5 in these carriers found a D450H missense mutation along the associated haplotype. These findings exemplify the power of haplotype analysis for mapping mutations in isolated populations and specifically for dissecting effects of multiple variants of the same locus.