gamma-sitosterol and Dyslipidemias

Investigating cholesterol metabolism, which derives from balancing cholesterol synthesis and absorption, opens new perspectives in the pathogenesis of dyslipidemias and the metabolic syndrome (MS). Cholesterol metabolism is studied by measuring plasma levels of campesterol, sitosterol and cholestanol, that is, plant sterols which are recognised as surrogate cholesterol-absorption markers and lathosterol or squalene, that is, cholesterol precursors, which are considered surrogate cholesterol-synthesis markers. This article presents current knowledge on cholesterol synthesis and absorption, as evaluated by means of cholesterol precursors and plant sterols, and discusses patterns of cholesterol balance in the main forms of primary hyperlipidaemia and MS. Understanding the mechanism(s) underlying these patterns of cholesterol synthesis and absorption will help to predict the response to hypolipidemic treatment, which can then be tailored to ensure the maximum clinical benefit for patients.

Topics: Biomarkers; Cholestanol; Cholesterol; Dyslipidemias; Humans; Lipid Metabolism; Metabolic Syndrome; Phytosterols; Sitosterols

Anagliptin, a dipeptidyl peptidase-4 inhibitor, is reported to reduce the level of low-density lipoprotein cholesterol (LDL-C). The underlying mechanism of this effect and effect on lipid metabolism however remains uncertain.. We therefore evaluate the effects of anagliptin on lipid metabolism-related markers compared with those of sitagliptin. The study was a secondary analysis using data obtained from the Randomized Evaluation of Anagliptin versus Sitagliptin On low-density lipoproteiN cholesterol in diabetes (REASON) trial. This trial in patients with type 2 diabetes at a high risk of cardiovascular events and on statin therapy showed that anagliptin reduced LDL-C levels to a greater extent than sitagliptin. Cholesterol absorption (campesterol and sitosterol) and synthesis (lathosterol) markers were measured at baseline and 52 weeks in the study cohort (n = 353).. There was no significant difference in the changes of campesterol or sitosterol between the two treatment groups (p = 0.85 and 0.55, respectively). Lathosterol concentration was increased significantly at 52 weeks with sitagliptin treatment (baseline, 1.2 ± 0.7 μg/mL vs. 52 weeks, 1.4 ± 1.0 μg/mL, p = 0.02), whereas it did not change in the anagliptin group (baseline, 1.3 ± 0.8 μg/mL vs. 52 weeks, 1.3 ± 0.7 μg/mL, p = 0.99). The difference in absolute change between the two groups showed a borderline significance (p = 0.06).. These findings suggest that anagliptin reduces LDL-C level by suppressing excess cholesterol synthesis, even in combination with statin therapy. Trial registration ClinicalTrials.gov number NCT02330406. https://clinicaltrials.gov/ct2/show/NCT02330406; registered January 5, 2015.

Topics: Aged; Biomarkers; Cholesterol; Cholesterol, LDL; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Dyslipidemias; Female; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Japan; Male; Middle Aged; Phytosterols; Pyrimidines; Sitagliptin Phosphate; Sitosterols; Time Factors; Treatment Outcome

We aimed to examine the effect of serum sitosterol, a cholesterol absorption marker, on clinical outcomes in acute coronary syndrome patients with dyslipidaemia.. This is a sub-analysis of the HIJ-PROPER trial that assesses the effect of aggressive low-density lipoprotein cholesterol (LDL-C) lowering treatment with pitavastatin + ezetimibe in 1734 acute coronary syndrome (ACS) patients with dyslipidaemia. Patients were divided into two groups based on sitosterol level at enrolment (cut-off value was 2.2 μg/mL; a median of baseline sitosterol level), and clinical outcomes were examined.. The mean LDL-C level after 3 years in the low sitosterol group was 84.8 ± 20.1 mg/dL with pitavastatin-monotherapy and 64.6 ± 20.3 mg/dL with pitavastatin + ezetimibe, while corresponding values in the high sitosterol group were 91.0 ± 22.9 mg/dL and 71.1 ± 23.3 mg/dL, respectively. In the high sitosterol group, the Kaplan-Meier event rate for the primary endpoint at 3 years was 26.0% in the pitavastatin + ezetimibe group, as compared with 34.3% in the pitavastatin-monotherapy group (hazard ratio, 0.71; 95% confidence interval, 0.56-0.91; p = 0.006, p-value for interaction = 0.010). However, in the low sitosterol group, there was no significant reduction of the primary endpoint by pitavastatin + ezetimibe therapy.. Aggressive lipid-lowering treatment with ezetimibe had a positive effect on clinical outcomes in the high sitosterol subset of ACS patients with dyslipidaemia, but not in the low sitosterol subset. This effect was independent of LDL-C reduction and suggests that sitosterol measurement on admission in ACS patients might contribute to a "personalised" lipid-lowering approach.

Topics: Acute Coronary Syndrome; Aged; Biomarkers; Cholesterol, LDL; Dyslipidemias; Ezetimibe; Female; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Japan; Male; Middle Aged; Predictive Value of Tests; Quinolines; Randomized Controlled Trials as Topic; Retrospective Studies; Risk Assessment; Risk Factors; Sitosterols; Time Factors; Treatment Outcome

The contribution of extra virgin olive oil (EVOO) macro- and micro-constituents in heart oxidative and inflammatory status in a hypercholesterolemic rat model was evaluated. Fatty acid profile as well as α-tocopherol, sterol, and squalene content was identified directly in rat hearts to distinguish the effect of individual components or to enlighten the potential synergisms.. Oils and oil-products with discernible lipid and polar phenolic content were used. Wistar rats were fed a high-cholesterol diet solely, or supplemented with one of the following oils, i.e., EVOO, sunflower oil (SO), and high-oleic sunflower oil (HOSO) or oil-products, i.e., phenolics-deprived EVOO [EVOO(-)], SO enriched with the EVOO phenolics [SO(+)], and HOSO enriched with the EVOO phenolics [HOSO(+)]. Dietary treatment lasted 9 weeks; at the end of the intervention blood and heart samples were collected.. High-cholesterol-diet-induced dyslipidemia was shown by increase in serum total cholesterol, low-density lipoprotein cholesterol, and triacylglycerols. Dyslipidemia resulted in increased malondialdehyde (MDA) and tumor necrosis factor-α (TNF-α) levels, while glutathione and interleukin 6 levels remained unaffected in all intervention groups. Augmentation observed in MDA and TNF-α was attenuated in EVOO, SO(+), and HOSO(+) groups. Heart squalene and cholesterol content remained unaffected among all groups studied. Heart α-tocopherol was determined by oil α-tocopherol content. Variations were observed for heart β-sitosterol, while heterogeneity was reported with respect to heart fatty acid profile in all intervention groups.. Overall, we suggest that the EVOO-polar phenolic compounds decreased MDA and TNF-α in hearts of cholesterol-fed rats.

Topics: alpha-Tocopherol; Animals; Cholesterol, Dietary; Cholesterol, HDL; Cholesterol, LDL; Diet; Diet, High-Fat; Dyslipidemias; Fatty Acids; Glutathione; Hypercholesterolemia; Inflammation; Interleukin-6; Male; Malondialdehyde; Olive Oil; Oxidative Stress; Phenols; Plant Oils; Rats; Rats, Wistar; Sitosterols; Sunflower Oil; Triglycerides; Tumor Necrosis Factor-alpha

High fat diet group showed a significant rise in serum and hepatic total cholesterol, triglyceride and atherogenic index which are major biomarkers of dyslipidemia and cardiovascular risk. The liver function markers, lipid peroxidation and proinflammatory cytokine levels were elevated in high fat diet group whereas antioxidant levels significantly reduced. These findings manifest hepatic damage which was further confirmed by histological findings. Quercetin and beta-sitosterol though structurally different yet both ameliorate the sickening changes in different mechanism. The current investigation is perhaps the first report of the mechanistic role of two polyphenols over dyslipidemia and subsequent hepatotoxicity.

Topics: Animals; Antioxidants; Cardiovascular Diseases; Diet, High-Fat; Dyslipidemias; Lipid Peroxidation; Lipids; Liver; Mice; Quercetin; Sitosterols; Triglycerides

Quantification of plasma noncholesterol sterols allows the study of cholesterol absorption and synthesis. A pattern of low cholesterol absorption and high synthesis has been demonstrated in patients with obesity and insulin resistance. To understand the relationship between cholesterol absorption/synthesis and visceral obesity, we investigated surrogate markers of cholesterol absorption (campesterol and sitosterol) and synthesis (lathosterol) in dyslipidaemic patients with different representation of abdominal fat, estimated by ultrasonographic measurement of visceral fat area (VFA).. In 126 patients with primary hyperlipaemias, plasma sitosterol, campesterol and lathosterol were determined by gas chromatography coupled with mass spectrometry. Visceral and subcutaneous fats were evaluated by ultrasonography. The study population was divided into two groups on the basis of VFA median values, below/equal and above 154 cm(2) . RESULTS Patients with higher VFA had significantly higher lathosterol levels (median 109 vs. 76 × 10(2) μmol/mmol cholesterol P < 0·004), body mass index, waist circumference, blood pressure, triglycerides, insulin, homoeostatic model assessment (HOMA)-IR and lower high-density lipoprotein (HDL)-C. VFA was positively correlated with lathosterol (ρ = 0·35, P < 0·001) and negatively with HDL-C (ρ = -0·43, P < 0·001), campesterol (ρ = -0·23, P = 0.01) and sitosterol (ρ = -0·35, P < 0·001). VFA was an independent predictor of lathosterol values (β = 0·389, P < 0·0001, P of the model < 0·0001);age, systolic blood pressure, BMI, waist circumference, triglycerides, HDL-C and HOMA failed to enter the final equation..   In hyperlipidaemic patients, the amount of visceral fat correlates with cholesterol synthesis; the use of ultrasonographic detection of abdominal adiposity allows a better characterization of cholesterol pathway, potentially useful for a tailored therapeutic approach.

Topics: Adult; Body Fat Distribution; Body Mass Index; Cholesterol; Chromatography, Gas; Dyslipidemias; Female; Humans; Intra-Abdominal Fat; Male; Mass Spectrometry; Middle Aged; Phytosterols; Sitosterols; Statistics as Topic; Ultrasonography; Waist Circumference

We investigated how liver fat content (LFC) influences cholesterol metabolism by quantifying liver fat using proton magnetic resonance spectroscopy and by measuring the serum concentrations of lathosterol, a marker of cholesterol synthesis, and sitosterol and campesterol, two markers of cholesterol absorption. We also evaluated whether this relationship could be modified by statin therapy. The study was conducted in 263 patients with type 2 diabetes, 137 of whom (52.0%) received statin therapy.. One hundred and sixty-five patients (62.7%) had steatosis (LFC>5.5%). We performed specific analyses in patients without statin therapy and in patients treated with statin therapy. In both groups, the lathosterol to cholesterol ratio correlated positively with LFC, and in multivariate analysis, the lathosterol to cholesterol ratio was associated with LFC independently of age, gender and BMI. Sitosterol and campesterol concentrations were not associated with LFC.. Our study suggests that in patients with type 2 diabetes, LFC is associated with an increase in cholesterol synthesis that is independent of obesity or diabetes mellitus. Statin therapy does not modify this relationship.

Topics: Aged; Biomarkers; Cholesterol; Diabetes Mellitus, Type 2; Dyslipidemias; Fatty Liver; Female; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Linear Models; Liver; Magnetic Resonance Spectroscopy; Male; Middle Aged; Multivariate Analysis; Non-alcoholic Fatty Liver Disease; Phytosterols; Risk Factors; Sitosterols; Treatment Outcome