scholarly journals A novel non-genetic murine model of hyperglycemia and hyperlipidemia-associated accelerated atherosclerosis

2021 ◽  
Author(s):  
Susanne Gaul ◽  
Khurrum Shahzad ◽  
Rebekka Medert ◽  
Ishan Gadi ◽  
Christina Meader ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Genetic Model ◽  
Diabetic Patients ◽  
Atherosclerotic Plaques ◽  
High Fat ◽  
Accelerated Atherosclerosis ◽  
Phenotypic Differences ◽  
Viral Particles ◽  
Characteristic Features ◽  
Genetic Mouse Models

Objective: Atherosclerosis, the main pathology underlying cardiovascular diseases is accelerated in diabetic patients. Genetic mouse models require breeding efforts which are time-consuming and costly. To establish a new non-genetic model of inducible metabolic risk factors mimicking hyperlipidemia, hyperglycemia, or both and allowing to detect phenotypic differences dependent on the metabolic stressor(s). Methods and Results: Wild type mice were injected with gain-of-function PCSK9D377Y (proprotein convertase subtilisin/kexin type 9) mutant adeno-associated viral particles (AAV) and streptozotocin and fed either a high-fat diet (HFD) or high-cholesterol/high fat-diet (Paigen diet, PD). Combined hyperlipidemic and hyperglycemic (HGHCi) mice, but not hyperlipidemia (HCi) alone, display characteristic features of accelerated atherosclerosis. Atherosclerotic plaques of HGHCi animals were larger, showed a less stable phenotype, contained more macrophages and less smooth muscle cells. These findings were observed both at early (12 weeks) and late (20 weeks) time points on both HFD or PD diet. Differences between the HGHCi and HCi model were confirmed using RNAseq analysis revealing that significantly more genes are dysregulated in mice with combined hyperlipidemia and hyperglycemia as compared to the hyperlipidemia only group. The HGHCi-associated genes were related to pathways regulating inflammation, cellular metabolism and collagen degradation. PD accelerates atherosclerosis in mice and shows plaque formation already after 8 weeks, therefore, representing a fast direct inducible hyperglycemic atherosclerosis model. Conclusion: We established a non-genetic inducible mouse model allowing comparative analyses of atherosclerosis in HCi and HGHCi conditions and its modification by diet, allowing analyses of multiple metabolic hits in mice.

scholarly journals Maintenance of AMPK activation by metformin is beneficial for suppressing the progress of diabetes-accelerated atherosclerosis via inhibition of vascular smooth muscle cells migration

2020 ◽  
Author(s):  
Yi Yan ◽  
Ting Li ◽  
Zhonghao Li ◽  
Mingyuan He ◽  
Dejiang Wang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
High Fat Diet ◽  
Muscle Cells ◽  
Atherosclerotic Plaques ◽  
Ampk Activation ◽  
High Fat ◽  
Accelerated Atherosclerosis

Abstract Background: Our previous work revealed that augmented AMPK activation inhibit cell migration by phosphorylating its substrate Pdlim5. As medial VSMCs contribute to the major composition of atherosclerotic plaques, a hypothesis is raised that modulation of AMPK-Pdlim5 signal pathway could retard the development of atherosclerosis through inhibiting migration of VSMCs. Therefore, we initiate the present study to investigate whether AMPK agonist like metformin is beneficial for suppressing diabetes-accelerated atherosclerosis in a diabetic mouse model induced by streptozotocin and high fat diet.Methods: For cell experiment, vascular smooth muscle cells (VSMCs) were overexpressed flag fused Pdlim5 and Pdlim5 mutant. Then the engineered VSMCs were introduced with metformin or control drug before determination of phosphorylated Pdlim5 with immunoblotting. For animal work, 8-week-old male ApoE−/−mice were induced diabetes with streptozotocin and then were randomly divided into 8 groups: control group, metformin hydrochloride (300 mg/kg/day) group, wildtype-Pdlim5 (Pdlim5 WT) carried adenovirus (Ad) group, Ad Pdlim5 WT and Met group, Ad Pdlim5 S177A group, Ad Pdlim5 S177A and Met group, Ad Pdlim5 S177D group, Ad Pdlim5 S177D and Met group. All mice were fed with high fat diet after virus infection. At the end, mice were sacrificed to observe atherosclerotic plaques and deposition of VSMCs in plaques. Moreover, 12–15-week-old Myh11-cre-EGFP male mice were accepted ligation of the left carotid artery and randomly divided into control and metformin treatment group. Finally, the injured vessel of Myh11-cre-EGFP mice were isolated to analyze the relationship between AMPK activation and neointima formation.Results: It was found that AMPK directly phosphorylate Pdlim5 at Ser177 in vitro, and metformin, an AMPK agonist, could induce phosphorylation of Pdlim5 indirectly and inhibition of cell migration as a result. Exogenous expression of phosphomimetic S177D-Pdlim5 inhibits lamellipodia formation and migration in VSMCs. It was also demonstrated that VSMCs contribute to the major composition of injury-induced neointimal lesions, while metformin could alleviate the occlusion of carotid artery in a wire-injury mice model. In order to investigate the function of AMPK-Pdlim5 pathway in the context of pathological condition, ApoE−/− male mice were divided randomly into control, streptozocin and high fat diet-induced diabetes mellitus, STZ + HFD together with metformin or Pdlim5 mutant carried adenovirus treatment groups. The results showed increased plasma lipids and aggravated vascular smooth muscle cells infiltration into the atherosclerotic lesion in diabetic mice compared with control mice. However, metformin alleviated diabetes-induced metabolic disorders and atherosclerosis, as well as decreased VSMCs infiltration in atherosclerotic plaques, while Pdlim5 phospho-abolished mutant carried adenovirus S177A-Pdlim5 undermine this protective function.Conclusions: The activation of AMPK-Pdlim5 pathway by chemicals like Metformin could inhibit formation of migratory machine of VSMCs and alleviate the progress of atherosclerotic plaques in diabetic mice. The maintenance of AMPK activity is beneficial for suppressing diabetes-accelerated atherosclerosis or metabolic syndrome.

Abstract 476: Shear Stress-induced Atherosclerotic Plaque Regression is Reversed by Regulation of Macrophage Mobility via Matrix Metalloproteinase Inhibition

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Stefania Simeone ◽  
Talin Ebrahimian ◽  
Veronique Michaud ◽  
Stephanie Lehoux
Keyword(s):  
Shear Stress ◽  
High Fat Diet ◽  
Fold Increase ◽  
Atherosclerotic Plaques ◽  
High Shear ◽  
High Fat ◽  
Gelatinase Activity ◽  
Mmp Inhibitor ◽  
Post Surgery ◽  
Plaque Regression

Atherosclerotic plaques form in regions of low blood flow, whereas vessels exposed to high shear stress remain lesion-free. We hypothesized that exposing established atherosclerotic plaques to elevated shear stress leads to lesion regression by facilitating inflammatory cell movement within the plaque. We developed a model of arteriovenous fistula (AVF) in mice, where the right carotid artery is anastomosed into the jugular vein. LDLR-/- mice were placed on a high-fat diet. Control mice were sacrificed at week 12, which coincided with sham and AVF surgery. Sham and AVF mice were kept on a high-fat diet for a further 4 weeks. This procedure increases the shear stress in the brachiocephalic artery (BCA) and leads to a 51% plaque regression in AVF. All groups had comparable lipid levels. However, BCA plaque macrophage, smooth muscle cell and collagen content was halved in AVF. We observed greater gelatinase activity in plaques of AVF mice, suggesting a role for matrix metalloproteinases (MMPs) in plaque regression. MMP-9 and MMP-3 expression was increased in AVF plaques whereas MMP-2 and MMP-14 expression was decreased (p<0.05). A separate group of mice was therefore treated post-surgery with an MMP inhibitor, doxycycline, or with a TIMP-1 over-expressing plasmid. Both prevented the reduction in plaque size in the AVF group. To better define the mechanism of plaque regression in the AVF, we devised an endothelial cell (EC)-macrophage co-culture system where the ECs were exposed to high, low or no shear stress, and macrophages exposed to the EC effluent. There was a 2.5 fold increase in the migration of macrophages exposed to high shear effluent vs. low shear (p<0.05). This coincided with a 3-fold increase in the number of macrophages expressing activated β1 integrin in the high shear conditions. Uptake of apoptotic cells by macrophages was also 25% higher in the high shear vs. static (p<0.05). When repeated using the MMP inhibitor, GM6001, the high shear increase in migration was blocked in the presence of MMP inhibition; however, it had no effect on cell phagocytosis. Our findings suggest that shear stress acting on ECs may influence the cells within the plaque by increasing MMP activity allowing for better macrophage motility, an important feature of regressing plaques.

scholarly journals Long-Lasting Exendin-4 Fusion Protein Improves Memory Deficits in High-Fat Diet/Streptozotocin-Induced Diabetic Mice

Pharmaceutics ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 159 ◽  
Author(s):  
Kyung-Ah Park ◽  
Zhen Jin ◽  
Jong Youl Lee ◽  
Hyeong Seok An ◽  
Eun Bee Choi ◽  
...  
Keyword(s):  
Glycemic Control ◽  
Fusion Protein ◽  
High Fat Diet ◽  
Memory Deficits ◽  
Receptor Expression ◽  
Diabetic Patients ◽  
Diabetic Mice ◽  
High Fat ◽  
Type 2 Diabetic

Glucagon-like peptide 1 (GLP-1) mimetics have been approved as an adjunct therapy for glycemic control in type 2 diabetic patients for the increased insulin secretion under hyperglycemic conditions. Recently, it is reported that such agents elicit neuroprotective effects against diabetes-associated cognitive decline. However, there is an issue of poor compliance by multiple daily subcutaneous injections for sufficient glycemic control due to their short duration, and neuroprotective actions were not fully studied, yet. In this study, using the prepared exendin-4 fusion protein agent, we investigated the pharmacokinetic profile and the role of this GLP-1 mimetics on memory deficits in a high-fat diet (HFD)/streptozotocin (STZ) mouse model of type 2 diabetic mellitus. After induction of diabetes, mice were administered weekly by intraperitoneal injection of GLP-1 mimetics for 6 weeks. This treatment reversed HFD/STZ-induced metabolic symptoms of increased body weight, hyperglycemia, and hepatic steatosis. Furthermore, the impaired cognitive performance of diabetic mice was significantly reversed by GLP-1 mimetics. GLP-1 mimetic treatment also reversed decreases in GLP-1/GLP-1 receptor expression levels in both the pancreas and hippocampus of diabetic mice; increases in hippocampal inflammation, mitochondrial fission, and calcium-binding protein levels were also reversed. These findings suggest that GLP-1 mimetics are promising agents for both diabetes and neurodegenerative diseases that are associated with increased GLP-1 expression in the brain.

scholarly journals IL-17A Is Proatherogenic in High-Fat Diet-Induced and Chlamydia pneumoniae Infection-Accelerated Atherosclerosis in Mice

2010 ◽  
Vol 185 (9) ◽  
pp. 5619-5627 ◽  
Author(s):  
Shuang Chen ◽  
Kenichi Shimada ◽  
Wenxuan Zhang ◽  
Ganghua Huang ◽  
Timothy R. Crother ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Chlamydia Pneumoniae ◽  
High Fat ◽  
Accelerated Atherosclerosis

scholarly journals Cholate-Containing High-Fat Diet Induces the Formation of Multinucleated Giant Cells in Atherosclerotic Plaques of Apolipoprotein E−/− Mice

2010 ◽  
Vol 30 (6) ◽  
pp. 1166-1173 ◽  
Author(s):  
Andriy O. Samokhin ◽  
Susan Wilson ◽  
Boram Nho ◽  
Maria Luisa Garcia Lizame ◽  
Osvaldo E. Eliseo Musenden ◽  
...  
Keyword(s):  
Apolipoprotein E ◽  
High Fat Diet ◽  
Giant Cells ◽  
Atherosclerotic Plaques ◽  
Multinucleated Giant Cells ◽  
High Fat

scholarly journals Dapagliflozin decreases atherosclerotic plaque instability via regulating macrophage pyroptosis

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
L Xu ◽  
Y Dai ◽  
K Yao ◽  
H Yang ◽  
A Sun ◽  
...  
Keyword(s):  
Microarray Analysis ◽  
Atherosclerotic Plaque ◽  
High Fat Diet ◽  
Foam Cell ◽  
Atherosclerotic Lesion ◽  
Plaque Formation ◽  
Public Institution ◽  
Foam Cell Formation ◽  
Diabetic Patients ◽  
High Fat

Abstract Background Vulnerable plaques are characterized by infiltration of inflammatory cells, playing a key role in the progression of acute coronary events. It's important to clarify the inflammatory mechanism of unstable plaque formation. Several clinical trials have demonstrated that dapagliflozin could reduce major adverse cardiac events in whether diabetic or non-diabetic patients. However, the underlying cardioprotective mechanism of dapagliflozin remains unclear. This study was aimed to investigate the role of dapagliflozin in regulating macrophage pyroptosis and vulnerable plaque formation. Methods 20 ApoE−/− mice (control) were fed with high fat diet while another 20 ApoE−/− mice were challenged with high fat diet plus dapagliflozin for 12 weeks. The extent and instability of atherosclerotic plaque was determined by oil-red staining, HE staining, immunofluorescence staining and electron microscopy. Changes in subsets of immune cells were evaluated by flow cytometry. Plasma cytokines were assessed by ELISA. Microarray analysis was applied to detect gene expressions while Western blot and real-time PCR was used to assess gene expression levels. Results Morphology studies revealed that dapagliflozin could inhibit plaque formation and reduce instability in ApoE−/− mice. FACS data showed that dapagliflozin could decrease CD11b+Ly6Chigh M1 macrophages differentiation and inhibit foam cells formation in ApoE−/− mice. Microarray analysis and in vitro studies exhibited that dapagliflozin could induce the down regulation of NLRP3, caspase-1, IL-1β, IL-18 and MMP-7/10/12/14 to retard macrophage pyroptosis and foam cell formation. Conclusions We have characterized a novel role for dapagliflozin in modulating atherosclerotic lesion development and progression. We envision that this study may provide several potential therapeutic targets for treatment of acute coronary syndromes. FUNDunding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Shanghai Sailing Program

scholarly journals Establishment of Type 2 Diabetes Mellitus Models Using High-Fat Diet and STZ in Bama Minipigs

2021 ◽  
Author(s):  
Yuqiong Zhao ◽  
Miaomiao Niu ◽  
Jia Yunxiao ◽  
Yuan Jifang ◽  
Xiang Lei ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Low Dose ◽  
Normal Diet ◽  
Large Animal Model ◽  
Control Group ◽  
Large Animal ◽  
High Cholesterol ◽  
High Fat ◽  
Accelerated Atherosclerosis ◽  
Atherosclerotic Lesions

Abstract BackgroundIn the past 20 years, the number of adults with diabetes has tripled. For most of the researches are often conducted in rodent T2DM models, and effective drugs developed have low clinical conversion efficiency. Therefore, it is urgent to establish a large animal model to explore the pathogenesis of T2DM and formulate disease prevention and control strategies. MethodsThis study was designed to establish and validate a T2DM model in minipigs with notable hyperglycemia using a high-fat diet and low-dose streptozotocin (STZ)，and examined the influence of STZ infusion time, the difference between a high-fat diet and a high-cholesterol and high-fat diet, and the atherosclerotic lesions accelerated by diabetes. Male Bama minipigs (n=24) were randomly divided into 5 groups; the control group was fed with normal diet for 9 months; STZ+HFD group and STZ+HCFD group were infused with 90 mg/kg STZ and then fed with a high-fat diet or high-cholesterol and high-fat diet for 9 months, respectively; HFD + STZ group and HCFD + STZ group were fed with a high-fat diet or high-cholesterol and high-fat diet, respectively, for nine months (after 3 months, pigs were injected with 90 mg/kg STZ intravenously). ResultsThe results showed the serum glucose concentrations were within the normal range in all groups except for HFD + STZ group and HCFD + STZ group. Animals fed with a high-fat diet for 9 months, did not develop apparent atherosclerotic lesions; nevertheless, atherosclerotic lesions were seen in animals fed with high-cholesterol and high-fat diets. Moreover, hyperglycemia accelerated atherosclerosis (lesions on the intimal surface of the abdominal aorta, 0.44±0.29 vs. 0.28±0.26) in minipigs. ConclusionsHigh-fat/high-cholesterol and high-fat diet combined with low-dose streptozotocin successfully established T2DM in minipigs. High-fat diet could not induce apparent atherosclerosis lesions but high-cholesterol and high-fat diet could during the nine months period. Hyperglycemia accelerated atherosclerosis in the minipigs.

Abstract 273: Shear Stress--Induced Atherosclerotic Plaque Regression Explained by Increased Macrophage Efferocytosis and Migration

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Stefania Simeone ◽  
Talin Ebrahimian ◽  
Veronique Michaud ◽  
Stephanie Lehoux
Keyword(s):  
Shear Stress ◽  
High Fat Diet ◽  
Cell Movement ◽  
Atherosclerotic Plaques ◽  
High Shear ◽  
High Fat ◽  
Mmp Inhibitor ◽  
Plaque Regression ◽  
Static Conditions

Atherosclerotic plaques form in regions of low blood flow, whereas vessels exposed to high shear stress remain lesion-free. Using a model of arteriovenous fistula (AVF) in mice, we have previously shown that exposing established atherosclerotic plaques to elevated shear stress leads to lesion regression and increased matrix metalloproteinase (MMP) activity. MMP inhibition abolished shear stress-induced plaque regression and macrophage migration, suggesting that facilitating inflammatory cell movement within the plaque contributes to regression. We hypothesized that increased shear stress also leads to more efficient efferocytosis, another important hallmark of regression. LDLR-/- mice were placed on a high-fat diet. Sham and AVF surgery was performed at week 12 and mice were kept on a high-fat diet for a further 4 weeks (wk16). Control mice were sacrificed at wk12. The AVF procedure increases the shear stress in the brachiocephalic artery (BCA) but does not alter serum lipid levels. Using 3D echocardiography between wk12 and wk16, we observed that plaques progressed in the BCA of sham mice, whereas the AVF plaques regressed. Furthermore, the size of the necrotic core was significantly smaller in the AVF plaques than sham and control (P<0.05). This could be due to increased efferocytosis in the AVF, as verified using an in vitro model of the plaque environment. Endothelial cells (EC) were co-cultured with macrophages in a system wherein ECs are exposed to high or no shear stress and macrophages are exposed to the EC effluent. Uptake of apoptotic cells by macrophages was 50% higher in the high shear vs. static conditions (P<0.01). The MMP inhibitor, GM6001, had no effect on efferocytosis. However, a cytokine array on the co-culture effluent revealed interesting candidates. CCL3 and GMCSF, both of which have been associated with enhanced efferocytosis, were more highly expressed in high shear conditions vs. static. Our findings suggest that shear stress increases efferocytosis, leading to smaller necrotic cores through a mechanism that probably involves altered cytokine production. The combination of more efficient cell migration and efferocytosis in the presence of increased shear stress likely leads to plaque regression.

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