Decreased Plasma Triglyceride Research Articles

FITM2 deficiency results in ER lipid accumulation, ER stress, and reduced apolipoprotein B lipidation and VLDL triglyceride secretion in vitro and in mouse liver

Triglycerides (TGs) associate with apolipoprotein B100 (apoB100) to form very low density lipoproteins (VLDLs) in the liver. The repertoire of factors that facilitate this association is incompletely understood. FITM2, an integral endoplasmic reticulum (ER) protein, was originally discovered as a factor participating in cytosolic lipid droplet (LD) biogenesis in tissues that do not form VLDL. We hypothesized that in the liver, in addition to promoting cytosolic LD formation, FITM2 would also transfer TG from its site of synthesis in the ER membrane to nascent VLDL particles within the ER lumen. Experiments were conducted using a rat hepatic cell line (McArdle-RH7777, or McA cells), an established model of mammalian lipoprotein metabolism, and mice. FITM2 expression was reduced using siRNA in cells and by liver specific cre-recombinase mediated deletion of the Fitm2 gene in mice. Effects of FITM2 deficiency on VLDL assembly and secretion invitro and invivo were measured by multiple methods, including density gradient ultracentrifugation, chromatography, mass spectrometry, stimulated Raman scattering (SRS) microscopy, sub-cellular fractionation, immunoprecipitation, immunofluorescence, and electron microscopy. 1) FITM2-deficient hepatic cells invitro and invivo secrete TG-depleted VLDL particles, but the number of particles is unchanged compared to controls; 2) FITM2 deficiency in mice on a high fat diet (HFD) results in decreased plasma TG levels. The number of apoB100-containing lipoproteins remains similar, but shift from VLDL to low density lipoprotein (LDL) density; 3) Both invitro and invivo, when TG synthesis is stimulated and FITM2 is deficient, TG accumulates in the ER, and despite its availability this pool is unable to fully lipidate apoB100 particles; 4) FITM2 deficiency disrupts ER morphology and results in ER stress. The results suggest that FITM2 contributes to VLDL lipidation, especially when newly synthesized hepatic TG is in abundance. In addition to its fundamental importance in VLDL assembly, the results also suggest that under dysmetabolic conditions, FITM2 may be an important factor in the partitioning of TG between cytosolic LDs and VLDL particles.

High-sucrose diet induces abnormalities in lipid metabolism through gut microbiome dysbiosis linked to five metronidazole-suppressed bacteria

Public attention to the correlation between excessive sucrose consumption and metabolic syndrome has facilitated research on its underlying mechanisms. Recent studies have newly identified the intestine, rather than the liver, as the predominant site of dietary fructose metabolism, which corrects the previous concepts and links the promotion of fatty liver and hyperlipidemia to gut microbiota dysbiosis, although the specific mode of action remains unclear. Here, we used microbiota suppression to identify the causative bacteria. Male Wistar rats were fed a starch or high-sucrose diet and orally administered two independent antibiotic treatments for four weeks. Metronidazole, neomycin, ampicillin, vancomycin, and their mixture were used to explore highly sucrose-responsive bacteria. Metronidazole and the mixture decreased or showed a tendency to decrease high-sucrose diet-induced increases in liver weight, plasma triglyceride levels, and fatty acid synthesis-related gene expression (ATP citrate lyase, fatty acid synthase, and malic enzyme). To further investigate the ability of metronidazole to ameliorate high-sucrose diet-induced abnormalities in lipid metabolism, three nitroimidazole antibiotics (metronidazole, tinidazole, and ornidazole) were used. Only metronidazole reduced the liver weight and decreased plasma triglyceride levels on a high-sucrose diet. Among the high-sucrose diet induction effects, five bacteria suppressed by metronidazole were screened, belonging to the family Rikenellaceae, genera Bacteroides, Blautia, and Dorea, and species Eubacterium dolichum. Overall, suppression of the gut microbiota by metronidazole-specific action, rather than the nitroreductase activity of tinidazole and ornidazole, was responsible for the amelioration of high-sucrose diet-induced fatty liver and hypertriglyceridemia. Five causative bacteria were identified in this study.

Comparative efficacy of therapeutic plasma exchange and insulin in hypertriglyceridemia-induced acute pancreatitis.

Hypertriglyceridemia-induced acute pancreatitis (HTG-AP) presents a therapeutic challenge with no currently definitive treatment, including therapeutic plasma exchange (TPE) and insulin. TPE aims to quickly reduce serum triglyceride (TG); however, its efficacy lacks convincing evidence. Intravenous insulin is a promising and convenient alternative, while comparative data is limited. This retrospective, single-center study compared TPE and insulin treatment in HTG-AP patients. The primary outcome measured was the percentage of TG reduction within 48hours of admission. The study included 33 TPE-treated and 56 insulin-treated patients. The TPE groups were more severe than those with medical therapy at baseline characteristics. A trend towards higher TG reduction within 24hours was observed in the TPE group (62.5% [IQR 51.7-83.3] vs. 55.7% [IQR 34.2-74.7], p = 0.038). However, no significant difference in TG reduction at 48hours was found between insulin and TPE groups (83.6% and 81.9%, respectively, p = 0.715). The TPE group exhibited extended hospital stays (10.0 [IQR 7.0-13.5] days vs. 6.0 [4.0-8.7] days, p = 0.001) without any difference in in-hospital mortality or time needed to lower TG below < 11.3mmol/L. In patients with HTG-AP, TPE decreased plasma triglyceride levels faster in the first 24hours than insulin therapy. However, there was no significant advantage after 48hours. Therefore, insulin may be a promising alternative and convenient treatment in carefully selected patients with HTG-AP.

A methionine-choline-deficient diet induces nonalcoholic steatohepatitis and alters the lipidome, metabolome, and gut microbiome profile in the C57BL/6J mouse

The methionine-choline-deficient (MCD) diet-induced non-alcoholic steatohepatitis (NASH) in mice is a well-established model. Our study aims to elucidate the factors influencing liver pathology in the MCD mouse model by examining physiological, biochemical, and molecular changes using histology, molecular techniques, and OMICS approaches (lipidomics, metabolomics, and metagenomics). Male C57BL/6J mice were fed a standard chow diet, a methionine-choline-sufficient (MCS) diet, or an MCD diet for 10 weeks. The MCD diet resulted in reduced body weight and fat mass, along with decreased plasma triglyceride, cholesterol, glucose, and insulin levels. However, it notably induced steatosis, inflammation, and alterations in gene expression associated with lipogenesis, inflammation, fibrosis, and the synthesis of apolipoproteins, sphingolipids, ceramides, and carboxylesterases.Lipid analysis revealed significant changes in plasma and tissues: most ceramide non-hydroxy-sphingosine lipids significantly decreased in the liver and plasma but increased in the adipose tissue of MCD diet-fed animals. Oxidized glycerophospholipids mostly increased in the liver but decreased in the adipose tissue of the MCD diet-fed group. The gut microbiome of the MCD diet-fed group showed an increase in Firmicutes and a decrease in Bacteroidetes and Actinobacteria. Metabolomic profiling demonstrated that the MCD diet significantly altered amino acid biosynthesis, metabolism, and nucleic acid metabolism pathways in plasma, liver, fecal, and cecal samples. LC-MS data indicated higher total plasma bile acid intensity and reduced fecal glycohyodeoxycholic acid intensity in the MCD diet group. This study demonstrates that although the MCD diet induces hepatic steatosis, the mechanisms underlying NASH in this model differ from those in human NASH pathology.

Evaluation of antihyperlipidemic effect of rosemary oil in streptozotocin-induced diabetic rats

Aim: In this study, the potential effects of rosemary oil on the lipid profile in streptozotocin-induced diabetic rats were examined. Materials and Methods: In this study, thirty-two adult male Wistar Albino rats were used. Working groups were consisted as follows: control group (C, n=6), rosemary group (R, n=6), diabetes group (STZ, n=10) and diabetes+rosemary group (STZ+R, n=10). The rosemary oil was administered at oral dosage of 200 mg/kg daily for duration of three weeks in the groups receiving rosemary oil. Diabetes was performed by subcutaneous injections of streptozotocin at dosage of 40 mg/kg in 0.1 M citrate buffer (pH 4.5) for two consecutive days as a single daily dose. At the end of three weeks, blood samples collected from the all animals were assessed lipid parameters. Results: In this study, plasma levels of triglyceride, total cholesterol, and LDL-cholesterol significantly elevated, alongside plasma HDL-cholesterol levels in diabetes group significantly reduced compared to the control group. However, upon the application of rosemary oil to streptozotocin-induced diabetic rats, a substantial decrease in plasma triglyceride, total cholesterol, and LDL-cholesterol levels was observed, while plasma HDL-cholesterol notably increased. Conclusion: As a result of the current findings, it is concluded that rosemary oil may have antihiperlipidemic properties and could be used as a phytomedicine for the treatment of diabetes.

Effects of the replacement corn meal by whole mango meal on tambaqui (Colossoma macropomum) diet: Digestibility, growth performance, biochemical, and hematological responses.

This study evaluated the digestibility of whole mango (Mangifera indica) meal (WMM) and determined the growth performance, intestinal enzyme activity, and metabolic and hematologic responses of tambaqui (Colossoma macropomum) juveniles fed diets containing different proportions of corn meal (CM) substitution by WMM. Fish fed with graded levels of WMM (0 (control), 80, 160, 240, and 320 g kg diet-1), replacing part of the dietary CM. The apparent digestibility coefficients of WMM were above 96%. Diets with WMM did not affect growth performance or intestinal enzyme activity. However, they showed a positive linear effect on plasma glucose, amino acids, and albumin levels and a negative linear effect on hepatic aspartate aminotransferase activity and hepatic glycogen, plasma cholesterol, and hemoglobin levels. Increased erythrocyte values and decreased plasma triglyceride levels were verified in fish fed 80 and 160 g WMM kg diet-1. In conclusion, the WMM may be a viable alternative to the tambaqui juveniles' diet, and WMM could replace up to 16% of CM without harming the growth and health of tambaqui juveniles.

AAV-mediated hepatic LPL expression ameliorates severe hypertriglyceridemia and acute pancreatitis in Gpihbp1 deficient mice and rats

GPIHBP1 plays an important role in the hydrolysis of triglyceride (TG) lipoproteins by lipoprotein lipases (LPLs). However, Gpihbp1 knockout mice did not develop hypertriglyceridemia (HTG) during the suckling period but developed severe HTG after weaning on a chow diet. It has been postulated that LPL expression in the liver of suckling mice may be involved. To determine whether hepatic LPL expression could correct severe HTG in Gpihbp1 deficiency, liver-targeted LPL expression was achieved via intravenous administration of the adeno-associated virus (AAV)-human LPL gene, and the effects of AAV-LPL on HTG and HTG-related acute pancreatitis (HTG-AP) were observed. Suckling Gpihbp1-/- mice with high hepatic LPL expression did not develop HTG, whereas Gpihbp1-/- rat pups without hepatic LPL expression developed severe HTG. AAV-mediated liver-targeted LPL expression dose-dependently decreased plasma TG levels in Gpihbp1-/- mice and rats, increased post-heparin plasma LPL mass and activity, decreased mortality in Gpihbp1-/- rat pups, and reduced the susceptibility and severity of both Gpihbp1-/- animals to HTG-AP. However, the muscle expression of AAV-LPL had no significant effect on HTG. Targeted expression of LPL in the liver showed no obvious adverse reactions. Thus, liver-targeted LPL expression may be a new therapeutic approach for HTG-AP caused by GPIHBP1 deficiency.

Probiotics Increase Intramuscular Fat and Improve the Composition of Fatty Acids in Sunit Sheep through the Adenosine 5'-Monophosphate-Activated Protein Kinase (AMPK) Signaling Pathway.

This experiment aims to investigate the impact of probiotic feed on growth performance, carcass traits, plasma lipid biochemical parameters, intramuscular fat and triglyceride content, fatty acid composition, mRNA expression levels of genes related to lipid metabolism, and the activity of the enzyme in Sunit sheep. In this experiment, 12 of 96 randomly selected Sunit sheep were assigned to receive the basic diet or the basic diet supplemented with probiotics. The results showed that supplementation with probiotics significantly increased the loin eye area, and decreased plasma triglycerides and free fatty acids, increasing the content of intramuscular fat and triglycerides in the muscle and improving the composition of the fatty acids. The inclusion of probiotics in the diet reduced the expression of adenosine 5'-monophosphate-activated protein kinase alpha 2 (AMPKα2) mRNA and carnitine palmitoyltransferase 1B (CPT1B) mRNA, while increasing the expression of acetyl-CoA carboxylase alpha (ACCα) mRNA, sterol regulatory element-binding protein-1c (SREBP-1c) mRNA, fatty acid synthase mRNA, and stearoyl-CoA desaturase 1 mRNA. The results of this study indicate that supplementation with probiotics can regulate fat deposition and improves the composition of fatty acids in Sunit sheep through the signaling pathways AMPK-ACC-CPT1B and AMPK-SREBP-1c. This regulatory mechanism leads to an increase in intramuscular fat content, a restructuring of muscle composition of the fatty acids, and an enhancement of the nutritional value of meat. These findings contribute to a better understanding of the food science of animal resources and provide valuable references for the production of meat of higher nutritional value.

Short hydrocarbon stapled ApoC2-mimetic peptides activate lipoprotein lipase and lower plasma triglycerides in mice.

Defects in lipolysis can lead to hypertriglyceridemia, which can trigger acute pancreatitis and is also associated with cardiovascular disease. Decreasing plasma triglycerides (TGs) by activating lipoprotein lipase (LPL) with ApoC2 mimetic peptides is a new treatment strategy for hypertriglyceridemia. We recently described a dual ApoC2 mimetic/ApoC3 antagonist peptide called D6PV that effectively lowered TG in several mouse models but has limitations in terms of drug development. The aim of this study was to create the next generation of ApoC2 mimetic peptides. We employed hydrocarbon staples, as well as select amino acid substitutions, to make short single helical mimetic peptides based on the last helix of ApoC2. Peptides were first tested for their ability to activate LPL and then in hypertriglyceridemia mouse models. All-atom simulations of peptides were performed in a lipid-trilayer model of TG-rich lipoproteins to discern their possible mechanism of action. We designed a single stapled peptide called SP1 (21 residues), and a double stapled (stitched) peptide called SP2 (21 residues) and its N-terminal acylated analogue, SP2a. The hydrocarbon staples increased the amphipathicity of the peptides and their ability to bind lipids without interfering with LPL activation. Indeed, from all-atom simulations, the conformations of SP1 and SP2a are restrained by the staples and maintains the proper orientation of the LPL activation motif, while still allowing their deeper insertion into the lipid-trilayer model. Intraperitoneal injection of stapled peptides (1-5 umoles/kg) into ApoC2-hypomorphic mice or human ApoC3-transgenic resulted in an 80%-90% reduction in plasma TG within 3 h, similar to the much longer D6PV peptide (41 residues). Other modifications (replacement L-Glu20, L-Glu21 with their D-isomers, N-methylation of Gly19, Met2NorLeu and Ala1alpha-methylAla substitutions, N-terminal octanoylation) were introduced into the SP2a peptide. These changes made SP2a highly resistant to proteolysis against trypsin, pepsin, and Proteinase K, while maintaining similar efficacy in lowering plasma TG in mice. We describe a new generation of ApoC2 mimetic peptides based on hydron carbon stapling that are at least equally potent to earlier peptides but are much shorter and resistant to proteolysis and could be further developed into a new therapy for hypertriglyceridemia.

Studi of In Vivo Antidiabetic Activity of Namnam Leaves (Cynometra cauliflora) Extract in Sprague Dawley Rat

Various treatments for Type 2 Diabetes Mellitus (T2DM) aim to alleviate hyperglycemia. Although natural products have been extensively utilized, their mechanism of action and efficacy as antidiabetic agents, particularly for T2DM, has not been extensively assessed in vivo. In this research, the leaves of the Namnam (Cynometra cauliflora) were extracted and tested for their activity as an antidiabetic agent. Sprague Dawley rats aged 3.5-4 months, weighing 200-250 g, were used as the experimental model, with a total of 30 individuals. The rats were induced with a high-fat diet and 30% sucrose until their blood glucose concentration reached ≥ 120 mg/dL. Subsequently, the rats were divided into four groups (groups 1, 2, 3, and 4). Over 21 days, changes in blood glucose, triacylglycerol, glycogen, and blood plasma insulin levels were assessed. The results demonstrated that the methanol extract of Namnam leaves (NLME) effectively reduced blood glucose levels by 23-34%, decreased plasma triglyceride levels by 13-30%, and increased liver glycogen levels by 68-96% compared to the control group (Diabetes). Among all the parameters assessed, NLME exhibited similar performance to metformin, a commonly prescribed diabetes medication (p&lt;0.05). Furthermore, the study revealed that NLME exerted antidiabetic effects, particularly for T2DM, by promoting liver glycogen formation, enhancing insulin secretion control, facilitating glucose absorption by muscles, and restricting fat metabolism in the blood

Effects of corn replacement by sorghum in broiler chickens diets on performance, blood chemistry, and meat quality

The influence of feeding a new hybrid of sorghum (ES Shamal, orange variety) in broiler chickens on growth, health, meat, and litter quality was evaluated from 1–42 d. A total of 360-day-old male Ross 308 broiler chicks (40.1 ± 2.3 g) were randomly assigned to 3 experimental diets: 100% corn-based diet (S0), partial replacement of corn with 50% sorghum (S50), total replacement of corn with sorghum (S100). All diets were calculated to be isonitrogenous and isocaloric with similar content of total lysine, total sulphur amino acids, calcium, and available phosphorous. The results indicated that partial or total replacement of corn by sorghum is suitable for broiler chicken diets with no adverse effects on growth, and slaughter performance, as well as litter quality over the whole trial period. Moreover, the substitution of corn with sorghum, reduced (p = .007) abdominal fat associated with an increase in breast and thigh meat colour (L* values; p < .001). Also, a significant (p = .002) decrease in plasma triglyceride was found in broilers fed sorghum-based diets. Except for collagen and hardness in the breast and thigh, and gumminess only in the thigh muscle, there were no differences in fundamental physicochemical (pH, protein, fat, moisture) or textural attributes of meat due to dietary treatment. However, sorghum alters the intestinal microflora, resulting in a lower count of E. coli in the caeca. It can thus, be concluded that sorghum (ES Shamal, orange variety) can be included in broiler feeds from hatching to day 42, without any adverse effects on the broiler’s performance. HIGHLIGHTS Climate changes become a threat to the livestock sector and finding novel nutritional solutions for feeding farm animals became a priority. New sorghum varieties are valuable in terms of drought-resistant plants. Replacement of corn with sorghum in broiler diets maintains growth performances and carcase characteristics.

Sulfosuccinimidyl oleate ameliorates the high-fat diet-induced obesity syndrome by reducing intestinal and hepatic absorption.

Background: A high-fat Western diet is a risk factor for obesity and steatosis. Reducing intestinal absorption of a high-fat diet (HFD) is a feasible strategy to control obesity. Sulfosuccinimidyl oleate (SSO) inhibits intestinal fatty acid transport. Therefore, the aim of this study was to investigate the effects of SSO on HFD-induced glucose and lipid metabolism in mice and its possible underlying mechanisms. Methods: Male C57/BL were fed a HFD (60% calories) for 12weeks and were administered an oral dose of SSO (50mg/kg/day). The expression of lipid absorption genes (CD36, MTTP, and DGAT1) and the serum levels of triglycerides (TGs), total cholesterol (TC), and free fatty acids (FFAs) were detected. Lipid distribution in the liver was detected by oil red and hematoxylin and eosin staining. In addition, serum levels of inflammatory factors, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were measured to detect side effects. Results: SSO was effective in the treatment of obesity and metabolic syndrome induced by HFD in mice. It attenuated the assembly of intestinal epithelial chylomicrons by inhibiting intestinal epithelial transport and absorption of fatty acids, thereby reducing the gene expression levels of MTTP and DGAT1, resulting in decreased plasma TG and FFA levels. At the same time, it inhibited the transport of fatty acids in the liver and improved the steatosis induced by a HFD. The results of oil red staining showed that SSO treatment can reduce lipid accumulation in the liver by 70%, with no drug-induced liver injury detected on the basis of interleukin-6, C-reactive protein, ALT, and AST levels. In addition, SSO treatment significantly improved insulin resistance, decreased fasting blood glucose levels, and improved glucose tolerance in HFD-fed mice. Conclusion: SSO is effective in the treatment of obesity and metabolic syndrome induced by a HFD in mice. SSO reduces intestinal fatty acid absorption by reducing the inhibition of intestinal CD36 expression, followed by decreased TG and FFA levels, which attenuates HFD-induced fatty liver.

Effects of dietary Pennyroyal essential oil on growth performance, digestive enzymes’ activity, and stress responses of common carp, Cyprinus carpio

This study aimed at assessing the effects of dietary Pennyroyal essential oil (PE) supplementation on growth performance, digestive enzymes, and stress, antioxidant, and immunological responses to an acute stress. Four experimental diets containing 0 (C), 100 (100PE), 250 (250PE), and 500 (500PE) mg/kg PE were used in this experiment. The fish were fed with these diets for eight weeks, followed by a 3-h crowding stress (40 kg/m3) and 24-h recovery. Growth performance, intestinal amylase, lipase, and protease activities, plasma total protein, albumin, and globulin levels were determined before stress, whereas plasma cortisol, glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), lysozyme, alternative complement (ACH50), total immunoglobulin (Ig), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and malondialdehyde (MDA) were measured before and after stress. Dietary PE supplementation significantly increased growth performance and digestive enzymes of the fish. The highest growth performance was observed in 250PE treatment. Highest amylase, lipase and protease activities were observed in 500PE, 250PE, and 250PE/500PE treatments, respectively. Dietary PE significantly increased plasma total protein, albumin, and globulin and decreased plasma triglyceride and cholesterol levels. Dietary PE supplementation significantly decreased cortisol, glucose, ALT, AST, and MDA before the crowding stress and mitigated the elevations in these parameters after stress. On the other hand, dietary PE significantly increased plasma lysozyme, ACH50, total Ig, SOD, CAT, and GPx before stress and mitigated the alteration in these parameters after stress. In conclusion, dietary PE at 250 mg/kg is recommended for common carp feed, as it improve growth performance, digestive enzymes’ activities, and physiological and immunological responses to acute stress in fish.

A novel homozygous nonsense variant of LMF1 in pregnancy-induced hypertriglyceridemia with acute pancreatitis

Hypertriglyceridemia (HTG)-induced pancreatitis during pregnancy could lead to maternal and fetal death. However, its genetic bases are not fully understood, and its treatment strategies are yet to be established.Here we report a case with a novel homozygous nonsense variant of LMF1 in pregnancy-associated HTG with acute pancreatitis.Our patient had childhood-onset severe HTG that had been well-controlled by dietary management in the non-pregnant period with plasma triglyceride (TG) levels at around 200 mg/dL. Milky plasma was noted at the first-trimester pregnancy checkup, followed by a severe increase in plasma TG (10,500 mg/dL) that resulted in pancreatitis in the last trimester. The implementation of strict dietary fat restriction (less than 4 grams per day) reduced plasma TG levels and led to successful delivery. Exome sequencing revealed a novel homozygous nonsense variant in LMF1 (c.697C>T, p.Arg233Ter). The activities of lipoprotein lipase (LPL) and hepatic lipase in post-heparin plasma were not abolished but reduced. The use of pemafibrate decreased plasma TG levels with a concomitant increase in LPL activity.HTG in childhood or early pregnancy is commonly assumed to be polygenic in origin but should be regarded as a feature suggestive of monogenic hyperchylomicronemia. Adequate TG monitoring and dietary fat restriction should be implemented to prevent potentially lethal events of pancreatitis.

CX08005, a Protein Tyrosine Phosphatase 1B Inhibitor, Attenuated Hepatic Lipid Accumulation and Microcirculation Dysfunction Associated with Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is one of the common metabolic diseases characterized by hepatic lipid accumulation. Insulin resistance and microcirculation dysfunction are strongly associated with NAFLD. CX08005, an inhibitor of PTP1B with the IC50 of 0.75 ± 0.07 μM, has been proven to directly enhance insulin sensitivity. The present study aimed to investigate the effects of CX08005 on hepatic lipid accumulation and microcirculation dysfunction in both KKAy mice and diet-induced obesity (DIO) mice. Hepatic lipid accumulation was evaluated by hepatic triglyceride determination and B-ultrasound analysis in KKAy mice. Insulin sensitivity and blood lipids were assessed by insulin tolerance test (ITT) and triglyceride (TG)/total cholesterol (TC) contents, respectively. In addition, the hepatic microcirculation was examined in DIO mice by in vivo microscopy. The results showed that CX08005 intervention significantly reduced the TG and echo-intensity attenuation coefficient in the livers of KKAy mice. Furthermore, we found that CX08005 treatment significantly enhanced insulin sensitivity, and decreased plasma TG and/or TC contents in KKAy and DIO mice, respectively. In addition, CX08005 treatment ameliorated hepatic microcirculation dysfunction in DIO mice, as evidenced by increased RBCs velocity and shear rate of the blood flow in central veins and in the interlobular veins, as well as enhanced rate of perfused hepatic sinusoids in central vein area. Additionally, CX08005 administration decreased the adhered leukocytes both in the center veins and in the hepatic sinusoids area. Taken together, CX08005 exhibited beneficial effects on hepatic lipid accumulation and microcirculation dysfunction associated with NAFLD, which was involved with modulating insulin sensitivity and leukocyte recruitment, as well as restoration of normal microcirculatory blood flow.

Inhibition of monoamine oxidase B reduces atherosclerosis and fatty liver in mice.

Oxidative stress is vital for pathophysiology of atherosclerosis and non-alcoholic fatty liver disease (NAFLD). Monoamine oxidase (MAO) is an important source of oxidative stress in the vascular system and liver. However, the effect of MAO inhibition on atherosclerosis and NAFLD has not been explored. In the present study, MAO A and B expressions were increased in atherosclerotic plaques in human and apolipoprotein E (ApoE)-deficient mice. Inhibition of MAO B (by deprenyl), but not MAO A (by clorgyline), reduced the atheroma area in the thoracic aorta and aortic sinus in ApoE-deficient mice fed the cholesterol-enriched diet for 15 weeks. MAO B inhibition attenuated oxidative stress, expression of adhesion molecules, production of inflammatory cytokines, and macrophage infiltration in atherosclerotic plaques and decreased plasma triglyceride and low-density lipoprotein (LDL) cholesterol concentrations. MAO B inhibition had no therapeutic effect on restenosis in the femoral artery wire-induced injury model in C57BL/6 mice. In the NAFLD mouse model, MAO B inhibition reduced lipid droplet deposition in the liver and hepatic total cholesterol and triglyceride levels in C57BL/6 mice fed high-fat diets for 10 weeks. Key enzymes for triglyceride and cholesterol biosynthesis (fatty acid synthase and 3-hydroxy-3-methylglutaryl-CoA reductase, HMGCR) and inflammatory markers were inhibited, and cholesterol clearance was up-regulated (increased LDL receptor expression and reduced proprotein convertase subtilisin/kexin type 9, PCSK9, expression) by MAO B inhibition in the liver. These results were also demonstrated in the HepG2 liver cell model. Our data suggest that MAO B inhibition is a potential and novel treatment for atherosclerosis and NAFLD.

Mirabegron-induced brown fat activation does not exacerbate atherosclerosis in mice with a functional hepatic ApoE-LDLR pathway

Activation of brown adipose tissue (BAT) with the β3-adrenergic receptor agonist CL316,243 protects mice from atherosclerosis development, and the presence of metabolically active BAT is associated with cardiometabolic health in humans. In contrast, exposure to cold or treatment with the clinically used β3-adrenergic receptor agonist mirabegron to activate BAT exacerbates atherosclerosis in apolipoprotein E (ApoE)- and low-density lipoprotein receptor (LDLR)-deficient mice, both lacking a functional ApoE-LDLR pathway crucial for lipoprotein remnant clearance. We, therefore, investigated the effects of mirabegron treatment on dyslipidemia and atherosclerosis development in APOE*3-Leiden.CETP mice, a humanized lipoprotein metabolism model with a functional ApoE-LDLR clearance pathway. Mirabegron activated BAT and induced white adipose tissue (WAT) browning, accompanied by selectively increased fat oxidation and attenuated fat mass gain. Mirabegron increased the uptake of fatty acids derived from triglyceride (TG)-rich lipoproteins by BAT and WAT, which was coupled to increased hepatic uptake of the generated cholesterol-enriched core remnants. Mirabegron also promoted hepatic very low-density lipoprotein (VLDL) production, likely due to an increased flux of fatty acids from WAT to the liver, and resulted in transient elevation in plasma TG levels followed by a substantial decrease in plasma TGs. These effects led to a trend toward lower plasma cholesterol levels and reduced atherosclerosis. We conclude that BAT activation by mirabegron leads to substantial metabolic benefits in APOE*3-Leiden.CETP mice, and mirabegron treatment is certainly not atherogenic. These data underscore the importance of the choice of experimental models when investigating the effect of BAT activation on lipoprotein metabolism and atherosclerosis.

Abstract 14556: Deep Phenotyping APOC3 Knockouts in a Population With High Consanguinity

Apolipoprotein C-III (APOC3) plays an integral role in the regulation of triglyceride-rich lipoproteins, by inhibiting the clearance of triglycerides carried by VLDL and chylomicron remnants in the blood. Prior work has shown that heterozygous loss of function (LOF) carriers of APOC3 have lower triglyceride levels and a lower risk of coronary artery disease (CAD). The quantitative impact of disease risk remains unknown in complete knockouts (KOs). Additionally, the effects and safety implications of complete APOC3 LOF have not been characterized. APOC3 inhibition is an active therapeutic strategy to lower CAD risk; hence these questions have therapeutic relevance. Among 37,244 unrelated sequenced individuals, including 19,681 cases of myocardial infarction (MI), in the Pakistan Genomic Resource - a biobank with high levels of consanguinity - we identified 207 heterozygous LOF carriers and 14 KOs. As expected, the KOs had undetectable APOC3 levels. We also observed a decrease in plasma triglycerides (P = 9E-85), VLDL-C levels (P = 2E-73), APOE levels (P = 5.4E-9) and an increase in HDL-C levels (P = 1E-34) and APOA1 levels (P = 6E-5) consistent with a gene-dosage effect. We observed a significant decrease in the risk of MI among heterozygous carriers (P = 0.01); however, we did not observe any protection from MI risk in complete KOs. Conversely, we observed a non-significant increase in the risk of MI in complete KOs compared to non-carriers; of the 14 knockouts identified, 9 were found to have MI. The loss of protection against MI could not be explained by the genetic background or by the increase in levels of homozygosity of the KOs. By recalling complete KOs and their family members, we were able to identify and phenotype an additional 33 complete KOs and 152 heterozygotes and assess other safety concerns related to complete APOC3 inhibition (i.e., glucose intolerance, fat content in the liver, etc.). In conclusion, by leveraging a highly consanguineous cohort, we have identified and phenotyped APOC3 KOs that have, hitherto, not been identified elsewhere. We did not observe APOC3 LOF to confer protection in complete KOs and observed other biomarker and phenotypic associations; these findings should inform existing therapeutic programs targeting APOC3.

Effects of Six Weeks of Hypoxia Exposure on Hepatic Fatty Acid Metabolism in ApoE Knockout Mice Fed a High-Fat Diet.

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease with a characteristic of abnormal lipid metabolism. In the present study, we employed apolipoprotein E knockout (ApoE KO) mice to investigate the effects of hypoxia exposure on hepatic fatty acid metabolism and to test whether a high-fat diet (HFD) would suppress the beneficial effect caused by hypoxia treatment. ApoE KO mice were fed a HFD for 12 weeks, and then were forwarded into a six-week experiment with four groups: HFD + normoxia, normal diet (ND) + normoxia, HFD + hypoxia exposure (HE), and ND + HE. The C57BL/6J wild type (WT) mice were fed a ND for 18 weeks as the baseline control. The hypoxia exposure was performed in daytime with normobaric hypoxia (11.2% oxygen, 1 h per time, three times per week). Body weight, food and energy intake, plasma lipid profiles, hepatic lipid contents, plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and molecular/biochemical makers and regulators of the fatty acid synthesis and oxidation in the liver were measured at the end of interventions. Six weeks of hypoxia exposure decreased plasma triglycerides (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) contents but did not change hepatic TG and non-esterified fatty acid (NEFA) levels in ApoE KO mice fed a HFD or ND. Furthermore, hypoxia exposure decreased the mRNA expression of Fasn, Scd1, and Srebp-1c significantly in the HFD + HE group compared with those in the HFD + normoxia group; after replacing a HFD with a ND, hypoxia treatment achieved more significant changes in the measured variables. In addition, the protein expression of HIF-1α was increased only in the ND + HE group but not in the HFD + HE group. Even though hypoxia exposure did not affect hepatic TG and NEFA levels, at the genetic level, the intervention had significant effects on hepatic metabolic indices of fatty acid synthesis, especially in the ND + HE group, while HFD suppressed the beneficial effect of hypoxia on hepatic lipid metabolism in male ApoE KO mice. The dietary intervention of shifting HFD to ND could be more effective in reducing hepatic lipid accumulation than hypoxia intervention.

Fenofibrate enhances lipid deposition via modulating PPARγ, SREBP-1c, and gut microbiota in ob/ob mice fed a high-fat diet.

Obesity is characterized by lipid accumulation in distinct organs. Presently, fenofibrate is a commonly used triglyceride-lowering drug. This study is designed to investigate whether long-term fenofibrate intervention can attenuate lipid accumulation in ob/ob mouse, a typical model of obesity. Our data demonstrated that fenofibrate intervention significantly decreased plasma triglyceride level by 21.0%, increased liver index and hepatic triglyceride content by 31.7 and 52.1%, respectively, and elevated adipose index by 44.6% compared to the vehicle group. As a PPARα agonist, fenofibrate intervention significantly increased the expression of PPARα protein in the liver by 46.3% and enhanced the expression of LDLR protein by 3.7-fold. However, fenofibrate dramatically increased the expression of PPARγ and SREBP-1c proteins by ~2.1- and 0.9-fold in the liver, respectively. Fenofibrate showed no effects on the expression of genes-related to fatty acid β-oxidation. Of note, it significantly increased the gene expression of FAS and SCD-1. Furthermore, fenofibrate modulated the gut microbiota. Collectively, long-term fenofibrate induces lipid accumulation in liver and adipose tissues in ob/ob mice by enhancing the expression of adipogenesis-related proteins and gut microbiota. These data suggest that fenofibrate may have limited effects on attenuating lipid deposition in obese patients.