Free Cholesterol Research Articles

Abstract 4113263: Serum Metabolomics Adds Predictive Value to Clinical and Polygenic Risk Scores for Atrial Fibrillation: A UK Biobank study of >240,000 Patients

Background: Atrial fibrillation (AF) poses substantial morbidity and mortality burdens globally. It is critical to identify individuals at high-risk for AF to implement both lifestyle modifications and close monitoring for initiation of oral anticoagulants. Currently, risk prediction in AF relies on clinical scores such as CHARGE-AF. Small molecule metabolites are thought to play a role in AF pathogenesis, but the additional predictive value of metabolomics over clinical and genetic risk factors is unknown. Using the UK Biobank (UKBB), we sought to perform this evaluation. Methods: We included all UKBB participants with complete 1 H-NMR metabolite measurements. We excluded participants with prior history of AF or with incomplete AF Polygenic Risk Score (AF-PRS) or CHARGE-AF components. The final cohort included 240,628 patients. In-patient records, primary care notes, and death registries were queried to identify patients who had developed incident AF within 5 years of enrollment. The cohort was divided into a 80/20:Train/Test split. We compared the performance of an Elastic-Net regularized Cox Proportional Hazards (EN-CPH) model trained on CHARGE-AF, AF-PRS, and the full 170 metabolite panel to a CPH model trained only on CHARGE-AF and AF-PRS. Results: Within 5 years, 4,174 (1.7%) patients developed AF. Compared to the control population, the incident AF cases were more likely to be older (62 vs. 56, p<0.001), male (65% vs 45%, p<0.001), and have higher CHARGE-AF and AF-PRS scores (p<0.001). After training the EN-CPH model on CHARGE-AF, AF-PRS, and 170 metabolites, the final model included 8 metabolites on top of CHARGE-AF (HR: 1.28) and AF-PRS (HR: 1.11). After adjusting for CHARGE-AF and AF-PRS, creatinine level was associated with increased risk of AF (HR: 1.01) while linoleic acid level (HR: 0.985) was associated with decreased risk. Furthermore, total cholesterol, esterified cholesterol, free cholesterol, cholesteryl esters in IDL, omega-6 fatty acids, and cholesterol in large LDL were associated with HR 0.993-0.999. The EN-CPH model out-performed the CPH model without metabolomics on the test set (AUC 0.786 vs 0.753, p < 0.001). Conclusions: The addition of metabolomics to clinical and genomic risk scores improves prediction of 5-year incident AF within a general population. This study highlights the significance of the metabolome as an independent prognosticator of AF risk. Further study of the mechanisms by which selected metabolites alter AF risk is needed.

Chitosan oligosaccharides: A potential therapeutic agent for inhibiting foam cell formation in atherosclerosis

Foam cell formation is a key hallmark in atherosclerosis and associated cardiovascular diseases (CVDs). The potential anti-atherosclerotic potential of chitosan oligosaccharides (COS) was investigated using oxLDL-treated RAW264.7 murine cells. COS treatment led to a significant inhibition of lipid accumulation, as demonstrated by Oil Red O staining, and reduced levels of total cholesterol, free cholesterol, cholesterol esters, and triglycerides in.oxLDL-treated RAW264.7 cells. COS blocked cholesterol influx through down-regulating class A1 scavenger receptors (SR-A1) and cluster of differentiation 36 (CD36) expression and stimulated cholesterol efflux through up-regulating ABC transporters ABCA-1 and ABCG-1 expressions. Additionally, COS treatment stimulated nuclear signaling pathways involving peroxisome proliferator-activated receptor-γ (PPAR-γ) and liver X receptor α (LXR-α), and also led to the phosphorylation of AMP-activated protein kinase (AMPK). COS further demonstrated anti-inflammatory effects by inhibiting the production of pro-inflammatory cytokines and the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in oxLDL-treated RAW264.7 cells, through suppression of NF-κB signaling. Furthermore, COS alleviated oxidative stress induced by oxLDL by activating Nrf2 signaling and enhancing the expression of antioxidant genes, including heme oxygenase-1 (HO-1), superoxide dismutase (SOD), glutathione peroxidase (Gpx), and catalase (CAT). In conclusion, COS can be beneficial in preventing atherosclerosis and related diseases.

Metabolomic profiling identifies signatures and biomarkers linking air pollution to dementia risk: a prospective cohort study

Exposure to air pollution has been associated with increased dementia. However, it remains unknown what specific metabolic mechanisms play a role in this relationship. We included 192,300 dementia-free participants from the UK Biobank cohort study. Annual concentrations of air pollution were assessed based on the residential address. Elastic net regression was performed to identify air pollution-related metabolites, and metabolic score was constructed. Cox regression models and covariate balancing generalized propensity scores (CBGPS) regression models were conducted to explore the longitudinal associations between air pollution/metabolic signatures and dementia risk. The underlying mechanisms between air pollution and dementia driven by metabolic signature or specific metabolites were also investigated. A total of 2,592 incident dementia cases were documented. We identified the metabolite profiles in response to air pollution exposure, including 87 metabolites for PM2.5, 65 metabolites for PM10, 76 metabolites for NO2, and 71 metabolites for NOx. The air pollution-related metabolic signatures were associated with increased risk of dementia, with hazard ratios (HR) of 1.17 (95% CI: 1.12, 1.22), 1.06 (95% CI: 1.02, 1.11), 1.16 (95% CI: 1.10, 1.21), and 1.17 (95% CI: 1.12, 1.22) for PM2.5, PM10, NO2 and NOx, respectively. The associations persisted using causal models. Metabolic signatures mediated the associations between air pollution exposure and dementia risk, with mediation proportions ranging from 6.57% to 12.71%. Additionally, we observed that a metabolite known as free cholesterol in medium VLDL (M-VLDL-FC) played a crucial mediating role. Our study provides novel insights into the metabolic mechanisms linking air pollution exposure to dementia risk.

Elevated free cholesterol levels due to impaired reverse cholesterol transport are a risk factor for polymicrobial sepsis in mice

Dysregulated lipid metabolism is commonly observed in septic patients, but how it contributes to sepsis remains largely unknown. Reverse cholesterol transport (RCT) is crucial for regulating cholesterol metabolism in circulation. During RCT, high-density lipoprotein (HDL) collects cholesterol from peripheral tissues and transports it to the liver’s scavenger receptor BI (SR-BI), where SR-BI mediates the uptake of cholesteryl esters from HDL for excretion via bile. In this study, we utilized AlbCreSR-BIfl/fl mice, a model with impaired RCT, to investigate the impact of RCT on sepsis. We found that AlbCreSR-BIfl/fl mice were significantly more susceptible to cecal ligation and puncture (CLP)-induced polymicrobial sepsis, with a survival rate of 14.3% compared to 80% in SR-BIfl/fl littermates. Mechanistically, sepsis disrupted cholesterol metabolism, causing a 4.8-fold increase in free cholesterol (FC) levels and a 4-fold increase in the FC/cholesteryl ester (CE) ratio in AlbCreSR-BIfl/fl mice compared to SR-BIfl/fl littermates. This disruption led to hemolysis and death. Notably, administering the cholesterol-lowering drug probucol normalized FC levels and the FC/CE ratio, and significantly improved survival in CLP-AlbCreSR-BIfl/fl mice. However, probucol treatment reduced survival in CLP-LDLR-/- mice, which had elevated CE levels with a low FC/CE ratio. These results highlight that elevated FC levels with high FC/CE ratio are a risk factor for sepsis. Therefore, selectively targeting elevated FC levels and FC/CE ratio could be a promising therapeutic strategy for managing sepsis.

Association of serum lipidomic profiles with risk of intracranial aneurysm: A Mendelian randomization study.

A two-sample Mendelian randomization (MR) analysis was utilized to assess the causal relationship between lipidomic profiles and the risk of intracranial aneurysms (IAs). Genetic variants related to lipidomic profiles (227 components) and IA [IA, aneurysmal subarachnoid hemorrhage (aSAH) only, unruptured IA (uIA) only] were obtained from published genome-wide association studies (GWASs) or the IEU Open GWAS project and used as instrumental variables for MR analysis. The inverse-variance weighted method was used in the primary analyses to derive causality estimates and was expressed as odds ratio (OR) with 95% confidence interval (CI). Of these 227 lipidomic profiles, only genetically predicted high levels of cholesterol to total lipids ratio in very small very-low-density lipoproteins (VLDL) [OR = 0.629 (95% CI, 0.504-0.786)], cholesteryl esters to total lipids ratio in very small VLDL [OR = 0.637 (95% CI, 0.509-0.797)], ratio of docosahexaenoic acid to total fatty acids [OR = 0.691 (95% CI, 0.582-0.820)], and ratio of polyunsaturated fatty acids to monounsaturated fatty acids [OR = 0.630 (95% CI, 0.522-0.760)] reduced the risk of aSAH, whereas genetically predicted high ratio of monounsaturated fatty acids to total fatty acids [OR = 1.471 (95% CI, 1.215-1.781)] increased the risk of aSAH. Moreover, genetically predicted high levels of cholesterol to total lipids ratio in very small VLDL [OR = 0.657 (95% CI, 0.542-0.798)], cholesteryl esters to total lipids ratio in very small VLDL [OR = 0.663 (95% CI, 0.548-0.803)], free cholesterol to total lipids ratio in small VLDL [OR = 0.682 (95% CI, 0.560-0.832)], phospholipids to total lipids ratio in small VLDL [OR = 0.674 (95% CI, 0.548-0.830)], and ratio of polyunsaturated fatty acids to monounsaturated fatty acids [OR = 0.678 (95% CI, 0.569-0.808)] reduced the risk of IA. The results of multivariable MR demonstrated that these causal associations persisted after adjusting for systolic blood pressure and cigarettes smoked per day. The effect of serum lipids on IA and aSAH may be mainly caused by subclasses of lipids such as VLDL.

Comparative effect of olive oil and flaxseed oil on drug induced hepatotoxicity in rats

AbstractThis study investigates the hepatoprotective effects of olive oil and flaxseed oil on chemically induced hepatotoxicity in rats by evaluating key biochemical parameters, including free fatty acids, iodine value, liver enzymes (ALP, ALT, AST), cholesterol, triglycerides, and HDL levels. The results demonstrated significant improvements in these markers with the administration of olive oil and flaxseed oil, either individually or in combination. The free fatty acid percentages and iodine values were consistent with the known nutritional properties of the oils. Notably, the combination of olive oil and flaxseed oil yielded the most substantial benefits, reducing ALP (115.53 ± 0.44 U/L), ALT (50.77 ± 1.46 U/L), and AST (52.12 ± 0.36 U/L) levels while improving lipid profiles by lowering cholesterol (135.4 ± 1.43 mg/dL) and triglyceride levels (57.14 ± 2.35 mg/dL) and increasing HDL levels (49.20 ± 0.45 mg/dL). These findings suggest that olive oil and flaxseed oil, due to their antioxidant and anti‐inflammatory properties, can effectively mitigate liver damage and promote lipid metabolism. The study supports the potential therapeutic application of these oils in managing liver health and preventing hepatotoxicity.

Effect of Moderate Beer Intake on the Lipid Composition of Human Red Blood Cell Membranes.

Background/Objectives: Growing evidence suggests that erythrocyte membrane lipids are subject to changes during their lifespan. Factors such as the type of dietary intake and its composition contribute to the changes in red blood cell (RBC) membranes. Due to the high antioxidant content of beer, we aimed to investigate the effect of moderate beer consumption on the lipid composition of RBCs membranes from healthy overweight individuals. Methods: We conducted a four-weeks, prospective two-arm longitudinal crossed-over study, where participants (n = 36) were randomly assigned to alcohol-free beer group or traditional beer group. The lipids of RBCs membranes were assessed at the beginning and the end of the intervention by thin-layer chromatography. Results: Four-weeks of alcohol-free beer promoted changes in fatty acids (FA), free cholesterol (FC), phosphatidylethanolamine (PE) and phosphatidylcholine (PC) (p < 0.05). Meanwhile, traditional beer intake led to changes in FA, FC, phospholipids (PL), PE and PC (p < 0.05). The observed alterations in membrane lipids were found to be independent of sex and BMI as influencing factors. Conclusions: The lipid composition of erythrocyte membranes is distinctly but mildly influenced by the consumption of both non-alcoholic and conventional beer, with no effects on RBC membrane fluidity.

IGF2/IGFBP4 reduces apoptosis and increases free cholesterol of chicken granulosa cells in vitro

Follicle selection, a crucial step in maintaining continuous egg production in chickens, is a process that relies on granulosa cells (GCs). In this study, we aimed to identify the key genes that are involved in follicle selection from our previous single-cell transcriptomic data. We used a combination of techniques and assays, including quantitative real-time PCR, immunofluorescence, Oil Red O staining, transmission electron microscopy (TEM), enzyme-linked immunosorbent assay (ELISA), monodansylcadaverine (MDC) assay, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, cell counting Kit-8 (CCK-8) assay, and 5-ethynyl-2-deoxyuridine (EdU) assay. Multiple indices, such as cell proliferation, cell differentiation, progesterone synthesis, lipid droplet production, total and free cholesterol content, apoptosis, and autophagy, were measured to determine the states of GCs in vitro. The results demonstrated that overexpression of genes related to insulin-like growth factor 2 (IGF2) or IGF-binding protein 4 (IGFBP4) increases intracellular free cholesterol (progesterone precursors) and lipid droplet production, inhibits apoptosis through increased autophagy, and inhibits cell proliferation. This indicates that IGF2 or IGFBP4 can maintain the survival state and improve differentiation tendency of chicken granulosa cells in vitro. Therefore, this study provides new evidence on the functions of IGFs and IGFBPs in chickens, establishing a crucial experimental foundation for understanding the regulatory mechanisms of follicle selection. In addition, our study contributes to understanding follicular development and improves the egg-laying performance of chickens.

Exploration of plasma biomarkers for Alzheimer's disease by targeted lipid metabolomics based on nuclear magnetic resonance (NMR) spectroscopy.

Alzheimer's disease (AD) is the most common cause of dementia, but the disease lacks convenient and cost-effective alternative biomarkers currently. We utilized targeted lipid metabolomics based on nuclear magnetic resonance (NMR) spectroscopy to identify plasma biomarkers in AD patients. Our study was a cross-sectional study that enrolled 58 AD patients and 40 matched health controls (HCs). Firstly, we identified plasma lipid metabolites that were significantly different between the two groups based on P < 0.05 and variable importance in the projection (VIP) > 1. Then we examined the correlation between the lipid metabolites and cognitive function using partial correlation analysis and assessed the diagnostic ability of the lipid metabolites using receiver operating characteristic (ROC) curves. Seventeen lipoproteins showed significant differences between AD patients and HCs among 114 lipid metabolites. All 17 lipoproteins were subtypes of low-density lipoprotein (LDL). Among them, LDL-3 particle number, LDL-3 apolipoprotein-B, LDL-3 phospholipids, LDL free cholesterol and LDL phospholipids were significantly correlated with cognitive function. The ROC curves showed that LDL-2 triglycerides (TG) and LDL-3 TG could significantly distinguish AD patients from HCs, with the area under the curve (AUC) above 0.7. In addition, we explored a strategy of combined diagnosis that significantly improved the diagnostic efficacy for AD (AUC = 0.879). Our study provides insight into the lipoprotein alterations associated with AD and potential biomarkers for its diagnosis and cognitive function assessment.

Mechanisms of Sigma-2/TMEM97 Involvement in Cholesterol Metabolism.

Extensive research has focused on cellular cholesterol and its regulation, primarily due to its crucial physiological roles and its association with numerous diseases resulting from dysregulated homeostasis. Consequently, investigating cholesterol metabolism and the network of regulating proteins remains an ongoing challenge for biomedical research seeking new molecular targets to manage aberrant cholesterol levels in pathologic conditions. There is evidence that Sigma-2/TMEM97 receptor regulates cholesterol metabolism. However, the mechanisms remain incompletely understood to date. Therefore, this study aimed to employ a pharmacological approach based on selective Sigma-2/TMEM97 agonists, rimcazole and siramesine, to uncover the contribution of this receptor to cholesterol homeostasis. Our results indicate that Sigma-2/TMEM97 activation modulates cholesterol uptake by altering key proteins involved in, leading to free cholesterol and neutral lipids accumulation. This sheds light on potential mechanisms implied, contributing a new piece to the intricate puzzle of cholesterol metabolism homeostasis.

SiRNA/CS-PLGA Nanoparticle System Targeting Knockdown Intestinal SOAT2 Reduced Intestinal Lipid Uptake and Alleviated Obesity.

Effective inhibition of intestinal lipid uptake is an efficient strategy for the treatment of disorders related to lipid metabolism. Sterol O-acyltransferase 2 (SOAT2) is responsible for the esterification of free cholesterol and fatty acids into cholesteryl esters. We found that intestine-specific SOAT2 knockout (Soat2I-KO) mice was capable to prevent the development of dietary induced obesity due to reduced intestinal lipid absorption. Soat2 siRNA/CS-PLGA nanoparticle system was constructed to enable intestinal delivery and inhibition of Soat2. This nanoparticle system was composed of PLGA-block-PEG and chitosan specifically delivering Soat2 siRNAs into small intestines in mice, effectively inhibit intestinal lipid uptake and resolving obesity. In revealing the underlying mechanism by which intestinal SOAT2 regulating fatty acid uptake, enhanced CD36 ubiquitination degradation was found in enterocytes upon SOAT2 inhibition. Insufficient free cholesterol esterification promotedendoplasmic reticulum stress and recruitment of E3 ligase RNF5 to activate CD36 ubiquitination in SOAT2 knockdown enterocytes. This work demonstrates a potential modulatory function of intestinal SOAT2 on lipid uptake highlighting the therapeutic effect on obesity by targeting intestinal SOAT2, exhibiting promising translational relevance in the siRNA therapeutic-based treatment for obesity.

Two-way Dispatched function in Sonic hedgehog shedding and transfer to high-density lipoproteins.

The Sonic hedgehog (Shh) signaling pathway controls embryonic development and tissue homeostasis after birth. This requires regulated solubilization of dual-lipidated, firmly plasma membrane-associated Shh precursors from producing cells. Although it is firmly established that the resistance-nodulation-division transporter Dispatched (Disp) drives this process, it is less clear how lipidated Shh solubilization from the plasma membrane is achieved. We have previously shown that Disp promotes proteolytic solubilization of Shh from its lipidated terminal peptide anchors. This process, termed shedding, converts tightly membrane-associated hydrophobic Shh precursors into delipidated soluble proteins. We show here that Disp-mediated Shh shedding is modulated by a serum factor that we identify as high-density lipoprotein (HDL). In addition to serving as a soluble sink for free membrane cholesterol, HDLs also accept the cholesterol-modified Shh peptide from Disp. The cholesteroylated Shh peptide is necessary and sufficient for Disp-mediated transfer because artificially cholesteroylated mCherry associates with HDL in a Disp-dependent manner, whereas an N-palmitoylated Shh variant lacking C-cholesterol does not. Disp-mediated Shh transfer to HDL is completed by proteolytic processing of the palmitoylated N-terminal membrane anchor. In contrast to dual-processed soluble Shh with moderate bioactivity, HDL-associated N-processed Shh is highly bioactive. We propose that the purpose of generating different soluble forms of Shh from the dual-lipidated precursor is to tune cellular responses in a tissue-type and time-specific manner.

Two-way Dispatched function in Sonic hedgehog shedding and transfer to high-density lipoproteins

The Sonic hedgehog (Shh) signaling pathway controls embryonic development and tissue homeostasis after birth. This requires regulated solubilization of dual-lipidated, firmly plasma membrane-associated Shh precursors from producing cells. Although it is firmly established that the resistance-nodulation-division transporter Dispatched (Disp) drives this process, it is less clear how lipidated Shh solubilization from the plasma membrane is achieved. We have previously shown that Disp promotes proteolytic solubilization of Shh from its lipidated terminal peptide anchors. This process, termed shedding, converts tightly membrane-associated hydrophobic Shh precursors into delipidated soluble proteins. We show here that Disp-mediated Shh shedding is modulated by a serum factor that we identify as high-density lipoprotein (HDL). In addition to serving as a soluble sink for free membrane cholesterol, HDLs also accept the cholesterol-modified Shh peptide from Disp. The cholesteroylated Shh peptide is necessary and sufficient for Disp-mediated transfer because artificially cholesteroylated mCherry associates with HDL in a Disp-dependent manner, whereas an N-palmitoylated Shh variant lacking C-cholesterol does not. Disp-mediated Shh transfer to HDL is completed by proteolytic processing of the palmitoylated N-terminal membrane anchor. In contrast to dual-processed soluble Shh with moderate bioactivity, HDL-associated N-processed Shh is highly bioactive. We propose that the purpose of generating different soluble forms of Shh from the dual-lipidated precursor is to tune cellular responses in a tissue-type and time-specific manner.

Royal Jelly Exerts a Potent Anti-Obesity Effect in Rats by Activating Lipolysis and Suppressing Adipogenesis.

Background/Objective: This study examined the anti-obesity effect of royal jelly (RJ) in rats fed with a high-fat diet by targeting the major pathways involved in adipogenesis and lipolysis. In addition, it examined whether this effect is AMPK-dependent. Methods: Five groups of adult male albino rats were used (n = 6 each as 1); the control rats were fed with a normal diet (2.9 kcal), and the other groups were as follows: control + RJ (300 mg/kg), HFD (4.75 kcal), HFD + RJ (300 mg/kg), and HFD + RJ (300 mg/kg) + dorsomorphin (an AMPK inhibitor) (0.2 mg/kg). Results: RJ was administered orally to all rats. With no changes in food and energy intake, RJ significantly reduced gains in body weight, fat weight, body mass index (BMI), the Lee index, abdominal circumference (AC), and the adiposity index (AI). It also reduced fasting glucose and insulin levels, HOMA-IR, and the circulatory levels of free fatty acids (FFAs), triglycerides, cholesterol, and LDL-c in the HFD-fed rats. RJ also increased serum glycerol levels and adiponectin levels, but reduced the serum levels of leptin, IL-6, and TNF-α. Moreover, RJ reduced the secretion of IL-6 and TNF-α from isolated WAT. At the tissue level, the HFD + RJ rats exhibited a smaller adipocyte size compared to the HFD rats. At the molecular level, RJ increased the phosphorylation of AMPK, SREBP1, and ACC-1 and increased the mRNA and protein levels of HSL and ATG in the WAT of the HFD rats. In concomitance, RJ increased the mRNA levels of PGC-α1, reduced the protein levels of PPARγ, and repressed the transcriptional activities of PPARγ, SREBP1, and C/EBPαβ in the WAT of these rats. All the aforementioned effects of RJ were prevented by co-treatment with dorsomorphin. Conclusions: RJ exerts a potent anti-obesity effect in rats that is mediated by the AMPk-dependent suppression of WAT adipogenesis and the stimulation of lipolysis.

Genetically predicted blood metabolites mediate relationships between gut microbiota and ovarian cancer: a Mendelian randomization study.

While there is evidence that gut microbiota (GM) and blood metabolites are associated with ovarian cancer (OC), the precise mechanisms underlying this relationship are still unclear. This study used Mendelian randomization (MR) to elucidate the causal connections between GM, blood metabolite biomarkers, and OC. In this study, we leveraged summary data for GM (5,959 individuals with genotype-matched GM), blood metabolites (233 circulating metabolic traits with 136,016 participants), and OC (63,702 participants with 23,564 cases and 40,138 controls) from genome-wide association studies (GWASs). We performed MR analysis to explore the causal relationship between GM and OC. Further, we harnessed univariable MR (UVMR) analysis to evaluate the causal associations between GM and circulating metabolites. Finally, we employed a two-step approach based on multivariable MR (MVMR) to evaluate the total genetic prediction effect of metabolites mediating the GM on the risk of OC to discover a potential causal relationship. In the MR analysis, 24 gut bacteria were causally associated with the pathogenesis of OC, including 10 gut bacteria (Dorea phocaeense, Succinivibrionaceae, Raoultella, Phascolarctobacterium sp003150755, Paenibacillus J, NK4A144, K10, UCG-010 sp003150215, Pseudomonas aeruginosa, and Planococcaceae) that were risk factors, and 14 gut bacteria (CAG-177 sp002438685, GCA-900066135 sp900066135, Enorma massiliensis, Odoribacter laneus, Ruminococcus E sp003521625, Streptococcus sanguinis, Turicibacter sp001543345, Bacillus velezensis, CAG-977, CyanobacteriaStaphylococcus A fleurettii, Caloranaerobacteraceae, RUG472 sp900319345, and CAG-269 sp001915995) that were protective factors. The UVMR analysis showed that these 24 positive gut bacteria were causally related to lipoproteins, lipids, and amino acids. According to the MVMR analysis, Enorma massiliensis could reduce the risk of OC by raising the total cholesterol to total lipids ratio in large low-density lipoprotein (LDL) and cholesteryl esters to total lipids ratio in intermediate-density lipoprotein (IDL). Turicibacter sp001543345, however, could reduce the risk of OC by lowering free cholesterol in small high-density lipoprotein (HDL) and increasing the ratios of saturated fatty acids to total fatty acids, total cholesterol to total lipids ratio in very small very-low-density lipoprotein (VLDL), and cholesteryl esters to total lipids ratio in very small VLDL. The current MR study provides evidence that genetically predicted blood metabolites can mediate relationships between GM and OC.

Carthamus tinctorius L. (Safflower) Flower Extract Attenuates Hepatic Injury and Steatosis in a Rat Model of Type 2 Diabetes Mellitus via Nrf2-Dependent Hypoglycemic, Antioxidant, and Hypolipidemic Effects.

This study aimed to examine the hepatic and anti-steatotic protective effects of methanolic extract from Carthamus tinctorius (safflower) flowers (SFFE), using a rat model of type 2 diabetes mellitus (T2DM), and to examine the molecular mechanisms underlying these effects. Adult male Wistar rats were used for this study. First, T2DM was induced in some rats by feeding them a high-fat diet (HFD) for 4 weeks, followed by a single dose of streptozotocin (STZ) (35 mg/kg, i.p.). Experimental groups included the following five groups (n = 8 in each): control, control + SFFE, T2DM, T2DM + SFFE, and T2DM + SFFE + brusatol (an Nrf2 inhibitor, 2 mg/kg, i.p.). SFFE was administered at a concentration of 300 mg/kg, and all experiments concluded after 8 weeks. Treatments with SFFE significantly reduced fasting blood glucose levels, free fatty acids (FFAs), cholesterol, triglycerides, and low-density lipoprotein cholesterol in both the control and T2DM rats, but they failed to reduce fasting insulin levels in these groups. SFFE treatments also improved the liver structure and reduced hepatocyte vacuolization and hepatic levels of triglycerides and cholesterol in T2DM rats, in addition to increasing the hepatic mRNA levels of keap1 and the cytoplasmic levels and nuclear activities of Nrf2 in both the control and T2DM rats. SFFE also stimulated the expression levels of PPARα and CPT-1 but reduced the malondialdehyde (MDA), mRNA levels of SREBP1, fatty acid synthase, and acetyl CoA carboxylase in both the control and T2DM rats; meanwhile, it reduced hepatic mRNA and the nuclear activities of NF-κB and increased levels of glutathione, superoxide dismutase, and heme oxygenase-1 in the livers of both groups of treated rats. Furthermore, SFFE suppressed the levels of caspase-3, Bax, tumor necrosis factor-α, and interleukin-6 in the T2DM rats. Treatment with brusatol prevented all of these effects of SFFE. In conclusion, SFFE suppresses liver damage and hepatic steatosis in T2DM through Nrf2-dependent hypoglycemic, antioxidant, anti-inflammatory, and hypolipidemic effects.

Inhibition of sterol O-acyltransferase 1 blocks Zika virus infection in cell lines and cerebral organoids

Viruses depend on host metabolic pathways and flaviviruses are specifically linked to lipid metabolism. During dengue virus infection lipid droplets are degraded to fuel replication and Zika virus (ZIKV) infection depends on triglyceride biosynthesis. Here, we systematically investigated the neutral lipid–synthesizing enzymes diacylglycerol O-acyltransferases (DGAT) and the sterol O-acyltransferase (SOAT) 1 in orthoflavivirus infection. Downregulation of DGAT1 and SOAT1 compromises ZIKV infection in hepatoma cells but only SOAT1 and not DGAT inhibitor treatment reduces ZIKV infection. DGAT1 interacts with the ZIKV capsid protein, indicating that protein interaction might be required for ZIKV replication. Importantly, inhibition of SOAT1 severely impairs ZIKV infection in neural cell culture models and cerebral organoids. SOAT1 inhibitor treatment decreases extracellular viral RNA and E protein level and lowers the specific infectivity of virions, indicating that ZIKV morphogenesis is compromised, likely due to accumulation of free cholesterol. Our findings provide insights into the importance of cholesterol and cholesterol ester balance for efficient ZIKV replication and implicate SOAT1 as an antiviral target.

Lipoprotein, Cholesterol, Treatment Strategies, and its Impact on Cardiovascular Diseases

A main cause of death internationally, cardiovascular (CV) illness accounted for about 31.4% of fatalities worldwide in 2012. According to estimates, a 33% decline in coronary heart disease (CHD) mortality in the United States between 1980 and 2000 was caused by a decrease in total cholesterol levels. Similar declines in CHD fatalities (varying from 19% to 46%) in other wealthy nations have been linked to lower total cholesterol levels. Lipoproteins are complex particles with a central core containing cholesterol esters and triglycerides surrounded by free cholesterol, phospholipids, and apolipoproteins, which facilitate lipoprotein formation and function. However, numerous individuals do not achieve LDL-C goal values because of statin resistance or adherence to statin medication. If cholesterol targets are not achieved with statins alone, alternative medicines include ezetimibe, fibrates, and nicotinic acid. In addition, people with familial high cholesterol levels (FH). Lipoprotein may act as a proinflammatory mediator that augments the lesion formation in atherosclerotic plaques. HDL metabolism represents a major target for the development of therapies intended to reduce the risk of atherosclerotic cardiovascular disease. Individual cardiovascular preventative treatments should be targeted largely at individuals at higher risk who will benefit most, with the prevention and treatment of dyslipidemia being viewed as a crucial component of those interventions. Since statins have been demonstrated to lessen the risk of serious vascular events by lowering low-density lipoprotein cholesterol (LDL-C), they continue to be the first-choice medication.

IL-16 Mediates the Effect of Circulating Metabolites on Postmenopausal Osteoporosis: A Two-Step, Multivariable Mendelian Randomization Study.

Objectives: This study aimed to explore the relationship between circulating metabolites and postmenopausal osteoporosis (PMOP) and to assess the mediating role of inflammatory factors. Methods: Utilizing summary-level data from genome-wide association studies (GWAS) and employing a Mendelian Randomization approach, a two-sample MR analysis was conducted to assess the relationship between circulating metabolites and PMOP. Additionally, a two-step MR was used to quantify the mediating impact of inflammatory factors on the effect of circulating metabolites on PMOP. Results: The results revealed a significant association between certain metabolites and the risk of PMOP, notably the ratio of free cholesterol to total lipids in very large VLDL particles (OR: 1.399, 95% CI: 1.002-1.954, p = 0.048) and IL-16 (OR: 0.773, 95% CI: 0.608-0.983, p = 0.036). IL-16 was found to partially mediate the impact of circulating metabolites on PMOP, with a mediation effect of 10.4%. Conclusion: This study underscores the crucial role of circulating metabolites and inflammatory factors in PMOP pathogenesis. A causal relationship between circulating metabolites and PMOP was established, with IL-16 mediating some effects. These findings hold promise for clinical applications in early detection, personalized medicine, and the identification of therapeutic targets for PMOP.

Association between serum remnant cholesterol level and metabolic dysfunction-associated steatotic liver histology.

Estimated remnant cholesterol (Rem-C) level, a risk factor for cardiovascular disease (CVD), is associated with metabolic dysfunction-associated steatotic liver disease (MASLD) diagnosed via ultrasonography. However, the relationship between accurate serum Rem-C level measurements and histological findings of MASLD remains unclear. We aimed to elucidate the relationship between accurately measured serum Rem-C levels and histological findings of MASLD. Cross-sectional single-center observational study. We assessed 222 patients (94 men and 128 women; age 20-80) who were diagnosed with MASLD via liver biopsy with available medical history, physical examination, and biochemical measurement data. Serum ester-type cholesterol and free cholesterol contents in the remnant lipoproteins were measured using an enzymatic method. Serum Rem-C levels were significantly higher in patients with NAFLD activity score (NAS) 5-8, ＞66% steatosis grade, lobular inflammation with ≥5 foci, and many cells/prominent ballooning cells (a contiguous patch of hepatocytes showing prominent ballooning injury) than in patients with NAS 1-4, <33% steatosis grade, lobular inflammation with <2 foci, and few ballooning cells (several scattered balloon cells), respectively. While univariate analysis revealed no significant association between Rem-C levels and advanced fibrosis, a significant association between Rem-C levels and NAS was evident. This relationship remained significant in multivariate analysis adjusted for confounders. Furthermore, in the analysis by sex, these relationships were significant for men but not for women. High serum Rem-C levels were associated with high NAS, but not with fibrosis stage, particularly in men. Controlling serum Rem-C level may improve MASLD activity.