Dietary-Induced Elevations of Triglyceride-Rich Lipoproteins Promote Atherosclerosis in the Low-Density Lipoprotein Receptor Knockout Syrian Golden Hamster

SR-A3 suppresses AKT activation to protect against MAFLD by inhibiting XIAP-mediated PTEN degradation

Scavenger receptor class A member 3 (SR-A3) is implicated in metabolic diseases; however, the relationship between SR-A3 and metabolic dysfunction-associated fatty liver disease (MAFLD) has not been documented. Here, we show that hepatic SR-A3 expression is significantly reduced in human and animal models in the context of MAFLD. Genetic inhibition of SR-A3 in hamsters elicits hyperlipidemia, hyperglycemia, insulin resistance, and hepatic steatosis under chow-diet condition, yet escalates in diet-induced MAFLD. Mechanistically, SR-A3 ablation enhances E3 ligase XIAP-mediated proteasomal ubiquitination of PTEN, leading to AKT hyperactivation. By contrast, hepatic overexpression of human SR-A3 is sufficient to attenuate metabolic disorders in WT hamsters fed a high-fat-high-cholesterol diet and ob/ob mice via suppressing the XIAP/PTEN/AKT axis. In parallel, pharmacological intervention by PTEN agonist oroxin B or lipid lowering agent ezetimibe differentially corrects MAFLD in hamsters.

Chylomicron Characteristics Are Associated With Microsomal Triglyceride Transfer Protein in an Animal Model of Diet-Induced Dysbiosis

Objective

Intestinal remnant chylomicrons (CMs) are involved in cardiovascular residual risk and the atherogenic process. Microsomal triglyceride transfer protein (MTTP) catalyzes the assembly of lipids to apolipoprotein B48, generating CMs. Dysbiosis could alter this behavior. This study investigated the chemical composition of CMs and their associations with intestinal MTTP and gut fat depots in a diet-induced dysbiosis animal model.

Methods

Male Wistar rats were fed either a standard diet (control, n=10) or a high-fat high-sucrose diet (HFSD, n=10) for 14 weeks. Measurements included serum glucose, lipid-lipoprotein profile, free fatty acids (FFAs), lipopolysaccharide (LPS) and the Firmicutes/Bacteroidetes (F/B) ratio in stool samples, via real-time quantitative polymerase chain reaction. Lipid content in isolated CMs (ultracentrifugation d <0.95 g/mL) was assessed, and MTTP, cell intestinal fat content (CIF), histology, apoB mRNA and tight junction (TJ) proteins were analyzed, in intestinal tissue.

Results

Compared to control, HFSD rats showed higher levels of LPS, triglycerides (TGs), non-high-density lipoprotein cholesterol (HDL-C) levels, TG/HDL-C ratio, FFAs, and the F/B ratio. HFSD CMs showed increased TG and phospholipids. TJ proteins levels were lower in the HFSD group, while histological scores showed no differences. CIF was increased in the HFSD group. No significant differences in apoB mRNA were found. MTTP expression was higher in the HFSD group, and directly correlated with CM-TG and inversely correlated with CIF.

Conclusion

Our findings imply that gut TG content may constitute an important determinant of the secretion of TG-rich CMs, promoted by MTTP, with increased atherogenic potential.

Role of Milk Intake in Modulating Serum Lipid Profiles and Gut Metabolites

BACKGROUND/OBJECTIVES

Milk is one of the main sources of nutrition in people's daily diet, but the fat in milk raises health concerns in consumers. Here, we aimed to elucidate the impact of Buffalo milk and Holstein cow milk consumption on blood lipid health through metabolomics analysis.

METHODS

Golden hamsters were administered Murrah Buffalo milk (BM) or Holstein cow milk (HM), and the body weight and serum lipid indicators were tested and recorded. The hamsters receiving equal amounts of physiological saline were used as the negative control (NC). Serum and fecal samples were collected, and LC-MS was used to identify the metabolites in the samples.

RESULTS

The results showed that both the BM and HM groups exhibited a significant reduction in body weight compared to that of the NC group from day 9, and the serum TG, TC, and LDL-C levels were significantly lower than those of the NC group. Further analysis identified 564 and 567 metabolites in the serum and fecal samples shared in the BM and HM groups and significantly different from those in the NC group, which were mainly enriched in the pathways related to lipid metabolism, such as fatty acid biosynthesis, arachidonic acid metabolism, and primary bile acid biosynthesis. Correlation analysis further suggested that milk intake can increase the levels of Muramic Acid, Oleoyl Ethanolamide, Seratrodast, Chenodeoxycholic Acid, Docosahexaenoic Acid Ethyl Ester, and Deoxycholic Acid in the serum and gut microbiota, which may affect TG, TC, HDL-C, and LDL-C in the serum, and thereby benefit the body's lipid health.

CONCLUSIONS

The results further confirmed that milk intake has a beneficial effect on blood lipid health by altering multiple metabolites in the serum and the gut. This study provides novel evidence that milk consumption is beneficial to health and is a reference for guiding people to a healthy diet.

Depleting LCAT Aggravates Atherosclerosis in LDLR-deficient Hamster with Reduced LDL-Cholesterol Level

INTRODUCTION

Lecithin cholesterol acyltransferase (LCAT) plays a crucial role in acyl-esterifying cholesterol in plasma, which is essential for reverse cholesterol transport (RCT). Previous studies indicated that its activity on both α and β lipoproteins interpret its effects on lipoproteins for many controversial investigations of atherosclerosis.

OBJECTIVES

To better understand the relationship between LCAT, diet-induced dyslipidemia and atherosclerosis, we developed a double knockout (LCAT-/-&LDLR-/-, DKO) hamster model to evaluate the specific role of LCAT independent of LDL clearance effects.

METHODS

Plasma triglyceride (TG), total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), and free cholesterol (FC) levels were measured using biochemical reagent kits. FPLC was performed to analyze the components of lipoproteins. Apolipoprotein content was assessed using western blotting (WB). The hamsters were fed a high cholesterol/high fat diet (HCHFD) to induce atherosclerosis. Oil Red O staining was employed to detect plaque formation. Peritoneal macrophages were studied to investigate the effects of LCAT on cholesterol uptake and efflux.

RESULTS

On HCHFD, DKO hamsters exhibited significantly elevated levels of TG and FC, while HDL-C was nearly undetectable without affecting TC levels, as compared to low-density lipoprotein receptor (LDLR)-deficient (LDLR-/-, LKO) hamsters. Lipoprotein profiling revealed a marked increase in plasma chylomicron/very low-density lipoprotein (CM/VLDL) fractions, along with an unexpected reduction in LDL fraction in DKO hamsters. Furthermore, DKO hamsters displayed aggravated atherosclerotic lesions in the aorta, aortic root, and coronary artery relative to LKO hamsters, attributed to a pro-atherogenic lipoprotein profile and impaired cholesterol efflux in macrophages.

CONCLUSIONS

Our study demonstrates the beneficial role of LCAT in inhibiting atherosclerotic development and highlights the distinctive lipid metabolism characteristics in hamsters with familial hypercholesterolemia.

Multi-omics reveals protective effects of Ling Gui Zhu Gan Decoction on hyperlipidaemia in hamster

Ling Gui Zhu Gan decoction (LGZGD) is a traditional Chinese medicine (TCM) prescription that is widely used in cardiovascular disease clinical prevention and treatment with high efficacy. Recent studies have shown that LGZGD can also be used in hyperlipidemia (HL) intervention, but its pharmacodynamic material basis and its mechanisms remains unclear. This study aimed to reveal the protective effects of LGZGD on HL, elucidate the pharmacodynamic material basis. The hamster HL model was established by high-fat diet. Thereafter, non-targeted metabolomics and quantitative lipidomics were established for screening differential metabolites and pathways. Finally, the mechanisms were elucidated based on network pharmacology to screen for shared targets, which were computational selected by molecular docking. After four weeks of LGZGD administration, the TC, TG, and liver index levels decreased notably and hepatocyte injury was obviously reduced. The Multi-omics identified 62 differential metabolites and 144 differential lipids, respectively. The network pharmacology study predicted 343, 85, and 974 relevant targets from LGZGD components, HL, differential metabolites and lipids, respectively. Eventually, seven core targets were selected by molecular docking. Six key components in LGZGD, including genistein and naringenin, could play a therapeutic role in HL by regulating seven pathways, including HMGCR and PPARA. This comprehensive strategy provides a promising example and approach for further research on TCM for the treatment of lipid metabolic diseases.

ApoB100 and Atherosclerosis: What's New in the 21st Century?

ApoB is the main protein of triglyceride-rich lipoproteins and is further divided into ApoB48 in the intestine and ApoB100 in the liver. Very low-density lipoprotein (VLDL) is produced by the liver, contains ApoB100, and is metabolized into its remnants, intermediate-density lipoprotein (IDL) and low-density lipoprotein (LDL). ApoB100 has been suggested to play a crucial role in the formation of the atherogenic plaque. Apart from being a biomarker of atherosclerosis, ApoB100 seems to be implicated in the inflammatory process of atherosclerosis per se. In this review, we will focus on the structure, the metabolism, and the function of ApoB100, as well as its role as a predictor biomarker of cardiovascular risk. Moreover, we will elaborate upon the molecular mechanisms regarding the pathophysiology of atherosclerosis, and we will discuss the disorders associated with the APOB gene mutations, and the potential role of various drugs as therapeutic targets.

Severe hypertriglyceridemia caused by Gpihbp1 deficiency facilitates vascular remodeling through increasing endothelial activation and oxidative stress

Hypertriglyceridemia (HTG) is an independent risk factor for atherosclerosis. However, its impact on non-atherosclerotic cardiovascular diseases remains largely unknown. Glycosylphosphatidylinositol anchored high-density lipoprotein binding protein 1 (GPIHBP1) is essential for the hydrolysis of circulating triglycerides and loss of functional GPIHBP1 causes severe HTG. In this study, we used Gpihbp1 knockout (GKO) mice to investigate the potential effects of HTG on non-atherosclerotic vascular remodeling. We compared the aortic morphology and gene expressions between three-month-old and ten-month-old GKO mice and their age-matched wild-type controls. We also conducted similar comparisons between GKO mice and wild-type controls in an angiotensin II (AngII)-induced vascular remodeling model. Our data showed that the intima-media wall of ten-month-old GKO mice but not three-month-olds was significantly thickened compared to wild-type controls. Moreover, ten-month-old GKO mice but not three-month-olds had increased aortic macrophage infiltration and perivascular fibrosis, along with increased endothelial activation and oxidative stress. Similarly, the AngII-induced vascular remodeling, as well as endothelial activation and oxidative stress, were also exacerbated in the GKO mice compared to wild-type controls. In conclusion, we demonstrated that severe HTG caused by Gpihbp1 deficiency could facilitate the onset and progression of non-atherosclerotic vascular remodeling through endothelial activation and oxidative stress in mice.

Lipid-Sensing Receptor FFAR4 Modulates Pulmonary Epithelial Homeostasis following Immunogenic Exposures Independently of the FFAR4 Ligand Docosahexaenoic Acid (DHA)

The role of pulmonary free fatty acid receptor 4 (FFAR4) is not fully elucidated and we aimed to clarify the impact of FFAR4 on the pulmonary immune response and return to homeostasis. We employed a known high-risk human pulmonary immunogenic exposure to extracts of dust from swine confinement facilities (DE). WT and Ffar4-null mice were repetitively exposed to DE via intranasal instillation and supplemented with docosahexaenoic acid (DHA) by oral gavage. We sought to understand if previous findings of DHA-mediated attenuation of the DE-induced inflammatory response are FFAR4-dependent. We identified that DHA mediates anti-inflammatory effects independent of FFAR4 expression, and that DE-exposed mice lacking FFAR4 had reduced immune cells in the airways, epithelial dysplasia, and impaired pulmonary barrier integrity. Analysis of transcripts using an immunology gene expression panel revealed a role for FFAR4 in lungs related to innate immune initiation of inflammation, cytoprotection, and immune cell migration. Ultimately, the presence of FFAR4 in the lung may regulate cell survival and repair following immune injury, suggestive of potential therapeutic directions for pulmonary disease.

Characterization of serum protein expression profiles in the early sarcopenia older adults with low grip strength: a cross-sectional study

Background

Sarcopenia refers to the progressive loss of skeletal muscle mass and muscle function, which seriously threatens the quality of life of the older adults. Therefore, early diagnosis is urgently needed. This study aimed to explore the changes of serum protein profiles in sarcopenia patients through a cross-sectional study, and to provide the reference for clinical diagnosis.

Methods

This study was a cross-sectional study carried out in the Tianjin institute of physical education teaching experiment training center from December 2019 to December 2020. Ten older adults were recruited, including 5 sarcopenia and 5 healthy older adults. After a detailed diagnostic evaluation, blood samples were collected to prepare serum for proteomic analysis using the HPLC System Easy nLC method. The differentially expressed proteins (DEPs) were screened by the limma package of R software (version 4.1.0).

Results

A total of 114 DEPs were identified between the patients and healthy older adults, including 48 up-regulated proteins and 66 down-regulated proteins. The functional enrichment analysis showed that the 114 DEPs were significantly enriched in 153 GO terms, which mainly involved in low-density lipoprotein particle remodeling, and negative regulation of immune response,etc. The PPI network further suggested that the cholesteryl ester transfer protein and Apolipoprotein A2 could serve as biomarkers to facilitate diagnosis of sarcopenia.

Conclusions

This study provided a serum proteomic profile of sarcopenia patients, and identified two proteins with diagnostic value, which might help to improve the diagnostic accuracy of sarcopenia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05844-2.

High remnant cholesterol level is relevant to diabetic retinopathy in type 2 diabetes mellitus

Background

Diabetic retinopathy (DR) is the primary oculopathy causing blindness in diabetic patients. Currently, there is increasing interest in the role of lipids in the development of diabetic retinopathy, but it remains controversial. Remnant cholesterol (RC) is an inexpensive and easily measurable lipid parameter; however, the relationship between RC and DR in type 2 diabetes mellitus (T2DM) has not been elucidated. This research investigates the relevance between RC levels and DR severity while building a risk prediction model about DR.

Methods

In this single-centre retrospective cross-sectional study. Each hospitalised T2DM patient had no oral lipid-lowering drugs in the past three months, and coronary angiography showed epicardial coronary artery stenosis of less than 50% and completed seven-field stereo photographs, fluorescein fundus angiography, and optical coherence tomography detection. The RC value is calculated according to the internationally recognised formula. Binary logistic regression was used to correct confounding factors, and the receiver operating characteristic (ROC) analysis was used to identify risk factors and assess the nomogram’s diagnostic efficiency.

Results

A total of 456 T2DM patients were included in the study. The RC levels in the DR team was higher [0.74 (0.60–1.12) mmo/l vs 0.54 (0.31–0.83) mmol/l P < 0.001] in the non-DR team. After adjusting for confounding elements, RC levels are still associated with DR risk (OR = 5.623 95%CI: 2.996–10.556 P < 0.001). The ratio of DR in every stage (except mild non-proliferative diabetic retinopathy) and DME in the high RC level team were further increased compared to the low-level team (all P < 0.001). After ROC analysis, the overall risk of DR was predicted by a nomogram constructed for RC, diabetes duration, and the neutrophil-lymphocyte ratio as 0.758 (95%CI 0.714–0.802 P < 0.001).

Conclusions

High RC levels may be a potential risk factor for diabetic retinopathy, and the nomogram does better predict DR. Despite these essential findings, the limitation of this study is that it is single-centred and small sample size analysis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01621-7.