Markers Of Cholesterol Synthesis Research Articles

Evaluation of plasma phytosterols in sitosterolemia, their kindreds and hyperlipidemia subjects

BackgroundPatients suffering from sitosterolemia with ABCG5/8 mutation typically present with early-onset or rapidly progressive atherosclerosis. Their kindreds with partial genetic deficiencies of ABCG5/8 are often considered healthy. However, discerning sitosterolemia from its familial kindreds and hyperlipidemia subjects has remained challenging. MethodsHere we retrospectively recruited seven families including 8 individuals diagnosed with sitosterolemia subjects, and 14 kindreds carrying single gene mutations. Additionally, 17 individuals with hyperlipidemia and 130 healthy controls served as positive and negative controls, respectively. A total of 6 phytosterols combined with cholesterol absorption indices (including sitosterol, campesterol, stigmasterol, and cholestanol) and cholesterol synthesis markers (desmosterol and 7-dehydrocholesterol), was compared across the aforementioned four groups. ResultsAs expected, the sitosterolemia subjects with double mutations demonstrated significantly elevated levels of sitosterol and other cholesterol absorption indices. Meanwhile, sitosterolemia kindreds with single gene mutation showed a similar pattern of activated cholesterol-absorption ability to the hyperlipidemia group, but not as high as the double mutation group. Notably, the cholesterol-synthesis enzyme 7-dehydrocholesterol reductase displayed an increase in the hyperlipidemia group but a decrease in the sitosterolemia kindred group, suggesting a potential discriminative role of 7-dehydrocholesterol in distinguishing between these two groups. The combination of phytosterols was more valuable than clinical lipid index for sitosterolemia diagnosis. ConclusionOur study revealed mild disruptions of cholesterol absorption capacities in sitosterolemia kindreds with single mutations. Furthermore, the combination of 6 phytosterols proved effective in distinguishing between sitosterolemia, its single mutation carriers, and hyperlipidemia patients.

The Effects of Pregestational Overweight and Obesity on Maternal Lipidome in Pregnancy: Implications for Newborns' Characteristics.

Obesity is an important risk factor for the development of pregnancy complications. We investigated the effects of pregestational overweight and obesity on maternal lipidome during pregnancy and on newborns' characteristics. The study encompassed 131 pregnant women, 99 with pre-pregnancy body mass index (BMI) < 25 kg/m2 and 32 with BMI ≥ 25 kg/m2. Maternal lipid status parameters, plasma markers of cholesterol synthesis and absorption and sphingolipids were determined in each trimester. Data on neonatal height, weight and APGAR scores were assessed. The results showed a higher prevalence (p < 0.05) of pregnancy and childbirth complications among the participants with elevated pregestational BMI. Levels of total cholesterol, HDL-cholesterol (p < 0.05) and LDL-cholesterol (p < 0.01) were significantly lower, and concentrations of triglycerides were higher (p < 0.05) in women with increased pre-gestational BMI. Lower concentrations of the cholesterol synthesis marker, desmosterol, in the 2nd trimester (p < 0.01) and the cholesterol absorption marker, campesterol, in each trimester (p < 0.01, p < 0.05, p < 0.01, respectively) were also found in this group. Markers of maternal cholesterol synthesis were in positive correlation with neonatal APGAR scores in the group of mothers with healthy pre-pregnancy weight but in negative correlation in the overweight/obese group. Our results indicate that gestational adaptations of maternal lipidome depend on her pregestational nutritional status and that such changes may affect neonatal outcomes.

Association of Serum Levels of Cholesterol Absorption and Synthesis Markers with the Presence of Cardiovascular Disease: The CACHE Study CVD Analysis.

Serum levels of cholesterol absorption and synthesis markers have been associated with cardiovascular risk in the United States and European countries. In this study, we examined the relevance of these biomarkers and the presence of cardiovascular disease (CVD) in Japanese individuals. The CACHE consortium, comprising of 13 research groups in Japan possessing data on campesterol, an absorption marker, and lathosterol, a synthesis marker measured by gas chromatography, compiled the clinical data using the REDCap system. Among the 2,944 individuals in the CACHE population, those with missing campesterol or lathosterol data were excluded. This cross-sectional study was able to analyze data from 2,895 individuals, including 339 coronary artery disease (CAD) patients, 108 cerebrovascular disease (CeVD) patients, and 88 peripheral artery disease (PAD) patients. The median age was 57 years, 43% were female, and the median low-density lipoprotein cholesterol and triglyceride levels were 118 mg/dL and 98 mg/dL, respectively. We assessed the associations of campesterol, lathosterol, and the ratio of campesterol to lathosterol (Campe/Latho ratio) with the odds of CVD using multivariable-adjusted nonlinear regression models. The prevalence of CVD, especially CAD, showed positive, inverse, and positive associations with campesterol, lathosterol, and the Campe/Latho ratio, respectively. These associations remained significant even after excluding individuals using statins and/or ezetimibe. The associations of the cholesterol biomarkers with PAD were determined weaker than those with CAD. Contrarily, no significant association was noted between cholesterol metabolism biomarkers and CeVD. This study showed that both high cholesterol absorption and low cholesterol synthesis biomarker levels were associated with high odds of CVD, especially CAD.

Cholesterol Absorption and Synthesis Markers: Risk for Cardiovascular Diseases?

Cholesterol Absorption and Synthesis Markers: Risk for Cardiovascular Diseases?

Sex‐specific plasma markers of cholesterol‐metabolism and plant sterols predict cognitive decline in older people – a ten years follow‐up study

AbstractBackgroundMultiple studies in clinical settings show that there is a link between a dysregulation of cholesterol metabolism and neurodegenerative pathologies and dementia. Diet‐based plant sterols may also interfere with neurodegeneration and cognitive decline through cholesterol‐lowering properties. In this study, we investigate whether circulating levels of cholesterol, its precursors, and metabolites, as well as triglycerides, and phytosterols predict cognitive decline ten years later in the general population. As a secondary objective we address the role of sex and the APOE genotype on these relationships.MethodWe considered 206 individuals aged 65 and older from a population‐based prospective study from Lausanne, Switzerland. A comprehensive cognitive assessment was performed at baseline and after ten years. We quantified the plasma levels of cholesterol, high‐density lipoprotein (HDL‐) cholesterol, triglyceride, cholesterol precursors (lathosterol, lanosterol, desmosterol, dihydrolanosterol), cholesterol derivatives (cholestanol), oxysterols (24S‐hydroxycholesterol [24S‐OHC], 7α‐hydroxycholesterol, 27‐hydroxycholesterol), and phytosterols (campesterol, campestanol, stigmasterol, sitosterol, sitostanol and brassicasterol) at baseline and after five years. Regression analysis (considering several possible confounder including APOE‐genotype) determined the relationship between baseline sterol levels, and their changes between baseline and five‐year follow‐up, with measures of cognitive decline (i.e. changes in Clinical Dementia Rating (CDR), Mini‐Mental State Exam and CDR Sum of Boxes) at ten years. Analyses were performed in the whole cohort, and in males and females independently.ResultHigher levels of baseline HDL‐cholesterol and lanosterol were associated with cognitive decline after ten years in the whole cohort. Decrease over time of 24S‐OHC was also associated with cognitive decline. In males, several cholesterol‐related sterols (cholestanol, lathosterol, lanosterol, 7α‐hydroxy‐cholesterol) and the phytosterol sitosterol were associated with cognitive decline. In females, only cholesterol and campestanol were associated with cognitive decline. The APOE genotype did not affect these associations.ConclusionIn this cohort of older people from the general population, plasma markers of cholesterol synthesis and metabolism and as well as phytosterols are associated with cognitive decline after ten years. These findings have potential relevance for sex‐specific risk assessment and prevention of cognitive decline in older people.

Pemafibrate has a novel mechanism of action to lower LDL-C and ApoB in patients with higher LDL-C levels: Insights from a phase 2 exploratory clinical pharmacology crossover study

Abstract Background Pemafibrate, a selective PPARα modulator (SPPARMα), decreases plasma TG and increases HDL-C. The effects of pemafibrate on cardiovascular outcomes were examined in patients with type 2 diabetes, moderately high TG, and low HDL-C who were on statin therapy (the PROMINENT trial) [1]. Against our expectation, the intervention with pemafibrate did not reduce the outcomes. The increases in LDL-C and ApoB observed in the trial may have mitigated the beneficial effects of lowering TG and remnants. On the contrary, pemafibrate decreased LDL-C and ApoB in some of the clinical trials conducted in Japanese population [2, 3], suggesting that the effects of pemafibrate on LDL-C and ApoB may vary depending on the target patient population. Purpose To clarify the mechanisms behind the LDL-C-lowering effects of pemafibrate, we evaluated the effects of pemafibrate on serum levels of lathosterol, beta-sitosterol and campesterol, surrogate markers for cholesterol synthesis and absorption. Methods This is a post hoc analysis of a Phase 2 study comparing a once-daily extended-release formulation (ER) of pemafibrate to a twice-daily immediate-release formulation (IR). The study was a multicentre, randomized, single-blind, 3-treatment, 2-period crossover clinical trial. Patients with fasting serum TG &amp;gt;150 mg/dL were treated with IR 0.2 mg/day (IR0.2), ER 0.4 mg/day (ER0.4), or ER 0.8 mg/day (ER0.8) for 4 weeks in each treatment period. We measured serum levels of TG, LDL-C, ApoB, lathosterol (a cholesterol synthesis marker), and beta-sitosterol and campesterol (cholesterol absorption markers) before and after the intervention and evaluated their correlations. Results Among 63 patients randomized, 60 received the study drug. At baseline, the mean TG was 221.3 mg/dL, LDL-C was 134.5 mg/dL, and 10% of patients were concomitantly treated with a statin. The least squares mean percentage changes from baseline at 4 weeks were -43.6%, -41.1%, and -39.7% for TG, -3.5%, -7.0%, and -11.3% for LDL-C, and -9.8%, -11.9%, and -13.4% for ApoB with IR0.2, ER0.4, and ER0.8, respectively, which were significant except for LDL-C with IR0.2. Lathosterol, beta-sitosterol, and campesterol significantly decreased with each dose (see Fig.). The percentage change in LDL-C was positively correlated with those in the synthesis and absorption markers. There was a trend that the reductions in LDL-C and lathosterol increased in a dose-dependent manner. The reduction in LDL-C was larger in the subgroup with higher baseline levels than those with lower baseline levels. Conclusion Pemafibrate reduced serum levels of LDL-C and ApoB. In parallel, they reduced serum markers for cholesterol synthesis and absorption. Because the percentage changes in LDL-C were significantly correlated with those in the absorption and synthesis markers, we would propose that pemafibrate reduced LDL-C by inhibiting both synthesis and absorption of cholesterol.

Efficacy and Safety of Pitavastatin/Ezetimibe Fixed-Dose Combination vs. Pitavastatin: Phase III, Double-Blind, Randomized Controlled Trial.

We compared the efficacy and safety of pitavastatin/ezetimibe fixed-dose combination with those of pitavastatin monotherapy in patients with hypercholesterolemia. This trial was a multicenter, randomized, double-blind, active-controlled, parallel-group trial. A total of 293 patients were randomly assigned into four groups receiving 2 mg pitavastatin, 4 mg pitavastatin, 2 mg pitavastatin/10 mg ezetimibe (K-924 LD), and 4 mg pitavastatin/10 mg ezetimibe (K-924 HD) once daily for 12 weeks. The percentage changes in lo w-density lipoprotein cholesterol (LDL-C), the primary endpoint, were －39.5% for 2 mg pitavastatin, －45.2% for 4 mg pitavastatin, －51.4% for K-924 LD, and －57.8% for K-924 HD. Compared with pitavastatin monotherapy, the pitavastatin/ezetimibe fixed-dose combination significantly reduced LDL-C, total cholesterol, and non-high-density lipoprotein cholesterol. Meanwhile, the cholesterol synthesis marker, lathosterol, was significantly decreased with pitavastatin monotherapy and the pitavastatin/ezetimibe fixed-dose combination, although the decrease was attenuated in the latter. On the other hand, the cholesterol absorption markers, beta-sitosterol and campesterol, were reduced with the fixed-dose combination but not with pitavastatin monotherapy. The incidence of adverse events and adverse drug reactions was not significantly different between the two groups receiving the fixed-dose combination and monotherapy. The mean values of laboratory tests that are related to liver function and myopathy increased but remained within the reference range in all groups. The pitavastatin/ezetimibe fixed-dose combination showed an excellent LDL-C-reducing effect by the complementary pharmacological action of each component, and its safety profile was similar to that of pitavastatin monotherapy (ClinicalTrials.gov Identifier: NCT04289649).

The expression of cholesterol synthesis and steroidogenic markers in females of the Chinese brown frog (Rana dybowskii) during pre-spawning and pre-hibernation.

The oviduct of the Chinese brown frog (Rana dybowskii) expands in pre-hibernation rather than in pre-spawning, which is one of the physiological phenomena that occur in preparation for hibernation. Steroid hormones are known to regulate oviductal development. Cholesterol synthesis and steroidogenesis may play important role in the expansion of the oviduct before hibernation. In this study, we investigated the expression patterns of the markers that are involved in the de novo steroid synthesis pathway in the oviduct of R. dybowskii during pre-spawning and pre-hibernation. According to histological analysis, the oviduct of R. dybowskii contains epithelial cells, glandular cells, and tubule lumens. During pre-hibernation, oviductal pipe diameter and weight were significantly larger than during pre-spawning. 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR), Low-density lipoprotein receptor (LDLR), steroidogenic acute regulatory protein (StAR), cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), and steroidogenic factor 1 (SF-1) were detected in epithelial cells in pre-hibernation and glandular cells during pre-spawning. HMGCR, LDLR, StAR, and P450scc protein expression levels were higher in pre-hibernation than during pre-spawning, but the SF-1 protein expression level did not significantly differ. HMGCR, LDLR, StAR, P450scc (CYP11A1), and SF-1 (NR5A1) mRNA expression levels were significantly higher in pre-hibernation compared to pre-spawning. The transcriptome results showed that the steroid synthesis pathway was highly expressed during pre-hibernation. Existing results indicate that the oviduct is able to synthesize steroid hormones using cholesterol, and that steroid hormones may affect the oviductal functions of R. dybowskii.

Serum Values of Cholesterol Absorption and Synthesis Biomarkers in Japanese Healthy Subjects: The CACHE Study HEALTHY Analysis.

Blood cholesterol absorption and synthesis biomarkers predict cardiovascular risk. This study aimed to determine the values of serum non-cholesterol sterol markers [lathosterol (Latho), campesterol (Campe), and sitosterol (Sito)] in healthy individuals and factors affecting these markers. The CACHE Consortium compiled clinical data, including serum Latho (cholesterol synthesis marker), and Campe and Sito (cholesterol absorption markers), by a gas chromatography method in 2944 individuals. Healthy subjects were selected by excluding those with prior cardiovascular disease, diabetes mellitus, hypertension, chronic kidney disease, familial hypercholesterolemia, sitosterolemia, current smokers, those with low ( ＜17 kg/m 2 ) or high (≥ 30 kg/m 2) body mass index (BMI), and those with treatment for dyslipidemia or hyperuricemia. Nonlinear regression stratified by sex was used to examine the associations of cholesterol metabolism markers with age, BMI, and serum lipid levels. Of 479 individuals selected, 59.4% were female; the median age was 48 years in females and 50 years in males. The three markers showed positively skewed distributions, and sex differences were present. Age was associated positively with Latho, inversely with Campe, but not significantly with Sito. BMI was associated positively with Latho, but not significantly with Campe or Sito. High-density lipoprotein cholesterol (HDL-C) was positively associated with Campe and Sito, but not significantly with Latho. Non-HDL-C was positively associated with the three markers. Our study results in the healthy subjects help to interpret the non-cholesterol sterol markers for cardiovascular risk assessment in patients with cardiovascular risk factors.

Association between Familial Hypercholesterolemia and Serum Levels of Cholesterol Synthesis and Absorption Markers: The CACHE Study FH Analysis.

Serum levels of cholesterol absorption and synthesis markers are known to be associated with cardiovascular risk. Familial hypercholesterolemia (FH) is a well-known inherited disorder presenting elevated low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) levels and premature coronary disease. In this study, we aim to examine the differences in terms of serum markers of cholesterol metabolism between FH and non-FH individuals and to examine their associations with serum lipid levels. In this study, we utilized data on serum markers of cholesterol metabolism, namely, lathosterol (Latho, synthesis marker), campesterol (Campe, absorption marker), and sitosterol (Sito, absorption marker) measured by gas chromatography of the CACHE consortium, which comprised of 13 research groups in Japan. Clinical data were compiled using REDCap system. Among the 2944 individuals in the CACHE population, we selected individuals without lipid-lowering medications and hemodialysis patients for this CACHE study FH analysis. Multivariable adjustment was performed to assess the associations. In this study, we analyzed data from 51 FH patients and 1924 non-FH individuals. After adjustment for possible confounders, the FH group was shown to have significantly higher Campe and Sito concentrations and insignificantly higher Latho concentrations than the non-FH group. These marker concentrations showed nonlinear associations with TC in the FH group. Campe/Latho and Sito/Latho ratios were significantly higher in the FH group than in the non-FH group. FH group had significantly elevated serum Campe and Sito concentrations and insignificantly elevated Latho concentrations; thus, intestinal cholesterol absorption relative to hepatic cholesterol synthesis was suggested to be elevated in patients with FH. Serum Latho, Campe, and Sito concentrations showed nonlinear associations with TC in the FH group.

Pregnancy Cholesterol Metabolism Markers and the Risk of Gestational Diabetes Mellitus: A Nested Case-Control Study.

This study aims to determine the association of pregnancy cholesterol metabolism markers with gestational diabetes mellitus (GDM) risk. We performed a nested case-control study in the Tongji Birth Cohort. GDM was diagnosed according to the 75 g 2 h oral glucose tolerance test (OGTT) at 24-28 gestational weeks. Nine cholesterol metabolism markers were detected using gas chromatography-mass spectrometry. Conditional logistic regression models were conducted. A total of 444 pregnant women were matched in a 1:2 ratio. The cholestanolTC and β-sitosterolTC in cholesterol absorption markers presented negative associations with the risks of GDM (adjusted OR: 0.77, 95% CI: 0.61-0.96; adjusted OR: 0.80, 95% CI: 0.64-1.00). The desmosterolTC in cholesterol synthesis markers were positively associated with the risks of GDM (adjusted OR: 1.25, 95% CI: 1.00-1.56), similar in the ratios of cholesterol synthesis to absorption markers. After adjustment for insulin or HOMA-IR, these effects were reduced. In conclusion, higher cholesterol synthesis and lower cholesterol absorption marker levels in the first pregnancy are associated with a higher risk of GDM, and insulin resistance may play a vital role in this association.

Cholesterol Metabolic Profiling of HDL in Women with Late-Onset Preeclampsia.

A specific feature of dyslipidemia in pregnancy is increased high-density lipoprotein (HDL) cholesterol concentration, which is probably associated with maternal endothelium protection. However, preeclampsia is most often associated with low HDL cholesterol, and the mechanisms behind this change are scarcely explored. We aimed to investigate changes in HDL metabolism in risky pregnancies and those complicated by late-onset preeclampsia. We analyze cholesterol synthesis (cholesterol precursors: desmosterol, 7-dehydrocholesterol, and lathosterol) and absorption markers (phytosterols: campesterol and β-sitosterol) within HDL particles (NCSHDL), the activities of principal modulators of HDL cholesterol's content, and major HDL functional proteins levels in mid and late pregnancy. On the basis of the pregnancy outcome, participants were classified into the risk group (RG) (70 women) and the preeclampsia group (PG) (20 women). HDL cholesterol was lower in PG in the second trimester compared to RG (p < 0.05) and followed by lower levels of cholesterol absorption markers (p < 0.001 for campesterolHDL and p < 0.05 for β-sitosterolHDL). Lowering of HDL cholesterol between trimesters in RG (p < 0.05) was accompanied by a decrease in HDL phytosterol content (p < 0.001), apolipoprotein A-I (apoA-I) concentration (p < 0.05), and paraoxonase 1 (PON1) (p < 0.001), lecithin-cholesterol acyltransferase (LCAT) (p < 0.05), and cholesterol ester transfer protein (CETP) activities (p < 0.05). These longitudinal changes were absent in PG. Development of late-onset preeclampsia is preceded by the appearance of lower HDL cholesterol and NCSHDL in the second trimester. We propose that reduced capacity for intestinal HDL synthesis, decreased LCAT activity, and impaired capacity for HDL-mediated cholesterol efflux could be the contributing mechanisms resulting in lower HDL cholesterol.

Rosacea Meibomian Gland Dysfunction Posterior Blepharitis May Be a Marker for Earlier Associated Dyslipidaemia and Inflammation Detection and Treatment with Statins.

Posterior blepharitis and dry eye are common disorders with meibomian gland dysfunction (MGD), a principal driver of their pathophysiology. Meibomian gland dysfunction is increasingly prevalent in older populations with contributory hormonal imbalances. The abnormal meibum in MGD has been documented to have an excess of cholesterol with a resultant disruption of the lipid layer of the tear film. This leads to tear film instability due to the inadequate trapping of the aqueous portion of the tear film with resultant evaporative dry eye. Significant morbidity may follow MGD with ocular surface inflammation disrupting both social and work function. Rosacea is a common chronic inflammatory condition of the central face but can have ocular and systemic inflammatory associations. It is especially prevalent in North European populations and can have onset at any age, but commonly presents between thirty and fifty years of age. In ocular rosacea, MGD is a recognised manifestation as is dyslipidaemia. Ocular rosacea can predate cutaneous disease. As yet, there is no directly reported evidence of the efficacy of the early identification and treatment of ocular rosacea with associated dyslipidaemia and systemic inflammation. We posit that MGD in ocular rosacea sufferers may be a marker for dysregulated cholesterol synthesis and inflammation, and that statins maybe a potential therapy. This article introduces potential strategies to utilise ocular rosacea MGD as a possible marker for ophthalmologists, cardiologists, and primary healthcare physicians to treat rosacea-associated dyslipidaemia and systemic inflammation. This could aid in overall cardiovascular morbidity and mortality control for rosacea sufferers, potentially at an earlier age, while also addressing their tear film de-stabilisation through cholesterol lowering and inflammation reduction.

619-P: An Isocaloric High Saturated Fat Diet Increases Endogenous Cholesterol Production Which Is Reversed by a Protein-Enriched Diet in Normal-Weight Humans

Lathosterol is a marker of endogenous cholesterol synthesis whereas plant sterols (e. g. campesterol) reflect cholesterol absorption. Obesity and type 2 diabetes mellitus are associated with increased endogenous cholesterol production and decreased cholesterol absorption. Only few studies evaluated cholesterol homeostasis under isocaloric nutritional conditions. This study investigated endogenous cholesterol production in healthy humans after consumption of isocaloric diets enriched with carbohydrates (KH) or saturated fat (HF) or protein (HP). 24 normal weight participants (women and men, age 18 - 70) were investigated for 18 weeks. An isocaloric diet rich in carbohydrates (55% carbohydrates, 30% fat, 15% protein, KH) was applied followed by an isocaloric diet rich in saturated fat (40% carbohydrates, 45% fat, 15% protein, HF) and finally followed by an isocaloric diet enriched with proteins (45% carbohydrates, 30% fat, 25% protein, HP); each for 6 weeks. Body weight (BW), serum total and LDL cholesterol and serum lathosterol and campesterol levels were analyzed after the KH period, after one week (HF1) and 6 weeks (HF6) of the HF and after the HP period. BW did not change during the study. Serum total and LDL cholesterol increased from 4.38±0.2 and 2.74±0.2 mmol/L, respectively at KH to 4.82±0.2 and 2.97±0.2 mmol/L, respectively at HF6 (both P&amp;lt;0.01) and were decreased back to KH levels at HP. Serum lathosterol levels increased 1.26-fold and 1.16-fold, respectively at HF1 and HF6 (P&amp;lt;0.05 compared to LF), however decreased by 10.1% at HP (compared to KH levels, P&amp;lt;0.05). Serum campesterol levels moderately decreased at HF1 and HF6 and were restored to KH levels at HP (P&amp;lt;0.01 compared to HF6). These data show that composition of macronutrients are responsible for diet induced elevation of serum cholesterol levels due to an increased endogenous cholesterol production in normal weight humans regardless of the energy content of the diet. Disclosure M.Kruse: None. S.Matysik: None. D.Hoffmann: None. T.Frahnow: None. A.F.Pfeiffer: Advisory Panel; Abbott Diabetes, Speaker's Bureau; Novo Nordisk, Sanofi-Aventis Deutschland GmbH. Funding German Federal Ministry of Education and Research (0315424)

Roux-en-Y gastric bypass induces hepatic transcriptomic signatures and plasma metabolite changes indicative of improved cholesterol homeostasis

Roux-en-Y gastric bypass (RYGB), the most effective surgical procedure for weight loss, decreases obesity and ameliorates comorbidities, such as non-alcoholic fatty liver (NAFLD) and cardiovascular (CVD) diseases. Cholesterol is a major CVD risk factor and modulator of NAFLD development, and the liver tightly controls its metabolism. How RYGB surgery modulates systemic and hepatic cholesterol metabolism is still unclear. We studied the hepatic transcriptome of 26 patients with obesity but not diabetes before and 1 year after undergoing RYGB. In parallel, we measured quantitative changes in plasma cholesterol metabolites and bile acids (BAs). RYGB surgery improved systemic cholesterol metabolism and increased plasma total and primary BA levels. Transcriptomic analysis revealed specific alterations in the liver after RYGB, with the downregulation of a module of genes implicated in inflammation and the upregulation of three modules, one associated with BA metabolism. A dedicated analysis of hepatic genes related to cholesterol homeostasis pointed towards increased biliary cholesterol elimination after RYGB, associated with enhancement of the alternate, but not the classical, BA synthesis pathway. In parallel, alterations in the expression of genes involved in cholesterol uptake and intracellular trafficking indicate improved hepatic free cholesterol handling. Finally, RYGB decreased plasma markers of cholesterol synthesis, which correlated with an improvement in liver disease status after surgery. Our results identify specific regulatory effects of RYGB on inflammation and cholesterol metabolism. RYGB alters the hepatic transcriptome signature, likely improving liver cholesterol homeostasis. These gene regulatory effects are reflected by systemic post-surgery changes of cholesterol-related metabolites, corroborating the beneficial effects of RYGB on both hepatic and systemic cholesterol homeostasis. Roux-en-Y gastric bypass (RYGB) is a widely used bariatric surgery procedure with proven efficacy in body weight management, combatting cardiovascular disease (CVD) and non-alcoholic fatty liver disease (NAFLD). RYGB exerts many beneficial metabolic effects, by lowering plasma cholesterol and improving atherogenic dyslipidemia. Using a cohort of patients undergoing RYGB, studied before and 1 year after surgery, we analyzed how RYGB modulates hepatic and systemic cholesterol and bile acid metabolism. The results of our study provide important insights on the regulation of cholesterol homeostasis after RYGB and open avenues that could guide future monitoring and treatment strategies targeting CVD and NAFLD in obesity.

Relation between single nucleotide polymorphisms in circadian clock relevant genes and cholesterol metabolism

Single nucleotide polymorphisms (SNPs) in circadian clock relevant genes are associated with several metabolic health variables, but little is known about their associations with human cholesterol metabolism. Therefore, this study examined associations between SNPs in ARNTL, ARNTL2, CLOCK, CRY1, CRY2, PER2, and PER3 with the intestinal cholesterol absorption markers campesterol and sitosterol, the endogenous cholesterol synthesis marker lathosterol, and total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) concentrations in 456 healthy individuals from Western European descent. One SNP in ARNTL2 (rs1037924) showed a significant association with lathosterol. Several SNPs in ARNTL (rs4146388, rs58901760, rs6486121), ARNTL2 (rs73075788), CLOCK (rs13113518, rs35115774, rs6832769), and CRY1 (rs2078074) were significantly associated with intestinal cholesterol absorption. Genetic variants in CRY2, PER2, and PER3 were not significantly associated with intestinal cholesterol absorption or endogenous cholesterol synthesis. None of the SNPs were associated with TC or LDL-C, except for one SNP in PER2 (rs11894491) with serum LDL-C concentrations. The findings suggest that various SNPs in ARNTL, ARNTL2, CLOCK and CRY1 play a role in intestinal cholesterol absorption and endogenous cholesterol synthesis, which was not reflected in TC and LDL-C concentrations. The significant associations between SNPs and intestinal cholesterol absorption and endogenous cholesterol synthesis should be validated in other cohorts.

Early effects of insulin therapy on cholesterol synthesis and absorption markers in patients with type 2 diabetes

Early effects of insulin therapy on cholesterol synthesis and absorption markers in patients with type 2 diabetes

A Transient Inflammatory Response Induced by Lipopolysaccharide Infusion Lowers Markers of Endogenous Cholesterol and Bile Acid Synthesis in Healthy Normocholesterolemic Young Men.

Inflammation is associated with changes in plasma lipids, lipoproteins, and cholesterol efflux capacity (CEC). It is unknown if the changes in lipids and lipoproteins during inflammation are related to changes in cholesterol absorption, synthesis, and bile acid synthesis. We, therefore, examined the effects of acute lipopolysaccharide (LPS)-induced transient systemic inflammation on lipids, lipoproteins, CEC, and markers of cholesterol metabolism. We also evaluated whether markers for cholesterol metabolism at baseline predict the intensity of the inflammatory response. Eight healthy young subjects received LPS infusion, and blood was sampled for the following 24 h. In addition to lipids, lipoproteins, and CEC, we also measured markers for cholesterol absorption and synthesis, bile acid synthesis, and inflammation. Compared with baseline, plasma total cholesterol, low-density lipoprotein cholesterol, and CEC decreased, while triglycerides increased in the 24 h following LPS infusion. TC-standardized levels of cholesterol synthesis markers (lathosterol, lanosterol, and desmosterol) and a bile acid synthesis marker (7α-OH-cholesterol) also decreased, with no changes in cholesterol absorption markers (campesterol, sitosterol, and cholestanol). Baseline TC-standardized levels of desmosterol and 7α-OH-cholesterol were positively correlated with concentrations of various inflammatory markers. Changes in TC-standardized desmosterol and 7α-OH-cholesterol were negatively correlated with concentrations of inflammatory markers. LPS infusion reduced endogenous cholesterol synthesis and bile acid synthesis in healthy young men.

Association of Kidney Function with Serum Levels of Cholesterol Absorption and Synthesis Markers: The CACHE Study CKD Analysis.

Serum levels of cholesterol absorption and synthesis markers are known to be associated with cardiovascular risk. Individuals with reduced kidney function or chronic kidney disease (CKD) are at an increased risk for cardiovascular disease. Hence, we examined the relationship between estimated glomerular filtration rate (eGFR) and serum markers of cholesterol absorption and synthesis. The CACHE (Cholesterol Absorption and Cholesterol synthesis in High-risk patiEnts) Consortium, comprised of 13 research groups in Japan possessing data of lathosterol (Latho, synthesis marker) and campesterol (Campe, absorption marker) measured via gas chromatography, compiled the clinical data using the REDCap system. Among the 3597 records, data from 2944 individuals were utilized for five analyses including this CKD analysis. This study analyzed data from 2200 individuals including 522 hemodialysis patients; 42.3% were female, the median age was 58 years, and the median eGFR was 68.9 mL/min/1.73 m2. Latho, Campe, and Campe/Latho ratio were significantly different when compared across CKD stages. When the associations of eGFR with these markers were assessed with multivariable nonlinear regression models, Latho, Campe, and Campe/Latho ratio showed positive, inverse, and inverse associations with eGFR. These associations were significantly modified by sex, the presence/absence of diabetes mellitus, and the presence/absence of statin use. We showed that individuals with lower eGFR have lower cholesterol synthesis marker levels and higher cholesterol absorption marker levels in this large sample.

Limb-girdle muscular dystrophy type 2B causes HDL-C abnormalities in patients and statin-resistant muscle wasting in dysferlin-deficient mice

Limb-girdle muscular dystrophy (MD) type 2B (LGMD2B) and Duchenne MD (DMD) are caused by mutations to the Dysferlin and Dystrophin genes, respectively. We have recently demonstrated in typically mild dysferlin- and dystrophin-deficient mouse models that increased plasma cholesterol levels severely exacerbate muscle wasting, and that DMD patients display primary dyslipidemia characterized by elevated plasma cholesterol and triglycerides. Herein, we investigate lipoprotein abnormalities in LGMD2B and if statin therapy protects dysferlin-deficient mice (Dysf) from muscle damage. Herein, lipoproteins and liver enzymes from LGMD2B patients and dysferlin-null (Dysf) mice were analyzed. Simvastatin, which exhibits anti-muscle wasting effects in mouse models of DMD and corrects aberrant expression of key markers of lipid metabolism and endogenous cholesterol synthesis, was tested in Dysf mice. Muscle damage and fibrosis were assessed by immunohistochemistry and cholesterol signalling pathways via Western blot. LGMD2B patients show reduced serum high-density lipoprotein cholesterol (HDL-C) levels compared to healthy controls and exhibit a greater prevalence of abnormal total cholesterol (CHOL)/HDL-C ratios despite an absence of liver dysfunction. While Dysf mice presented with reduced CHOL and associated HDL-C and LDL-C-associated fractions, simvastatin treatment did not prevent muscle wasting in quadriceps and triceps muscle groups or correct aberrant low-density lipoprotein receptor (LDLR) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) protein expression. LGMD2B patients present with reduced serum concentrations of HDL-C, a major metabolic comorbidity, and as a result, statin therapy is unlikely to prevent muscle wasting in this population. We propose that like DMD, LGMD2B should be considered as a new type of genetic dyslipidemia.