Atherosclerotic Rabbits Research Articles

Omega-3 polyunsaturated fatty acids, especially DHA and EPA, remold gut microbiota to suppress inflammation in rabbits with atherosclerosis

Atherosclerosis (AS) caused by a high-fat diet becomes a critical cause of cardiovascular diseases, which has been regarded as an urgent public health problem. Omega-3 polyunsaturated fatty acids (omega-3 PUFAs) have many beneficial effects on human health. However, in recent years, the critical role of gut microbiota in atherosclerosis has been gradually proposed, and the impact of omega-3 PUFAs on cardiovascular diseases via gut microbiota in rabbits remains unknown. Likewise, the role of omega-3 PUFAs in regulating endothelial lesions, visceral injury, and vascular inflammation caused by high-fat diet-induced trimethylamine-nitrogen oxide (TMAO) has not been reported. Here, we investigated the effects of omega-3 PUFAs administered orally on atherosclerosis via an atherosclerotic rabbit model induced by a high-fat diet. The results showed that omega-3 PUFAs obtained from deep-sea fish oil can alleviate high-fat diet-induced atherosclerosis by inhibiting the increase of plasma TMAO and the formation of liver foam cells, reducing inflammatory factors, fat deposition, and plasma lipid levels and suppressing organ damage. Furthermore, gut microbiota disrupted by a high-fat diet were remodeled in rabbits treated with omega-3 PUFAs. These results further confirm that omega-3 PUFAs are promising nutritional and medical health foods that can be supplemented daily to prevent cardiovascular diseases.

Multimodal Imaging-Assisted Intravascular Theranostic Photoactivation on Atherosclerotic Plaque.

Atherosclerosis is a chronic inflammatory disease causing a fatal plaque rupture, and its key aspect is a failure to resolve inflammation. We hypothesize that macrophage-targeted near-infrared fluorescence emitting photoactivation could simultaneously assess macrophage/lipid-rich plaques in vivo and facilitate inflammation resolution. We fabricated a Dectin-1-targeted photoactivatable theranostic agent through the chemical conjugation of the near-infrared fluorescence-emitting photosensitizer chlorin e6 and the Dectin-1 ligand laminarin (laminarin-chlorin e6 [LAM-Ce6]). Intravascular photoactivation by a customized fiber-based diffuser after administration of LAM-Ce6 effectively reduced inflammation in the targeted plaques of atherosclerotic rabbits in vivo as serially assessed by dual-modal optical coherence tomography-near-infrared fluorescence structural-molecular catheter imaging after 4 weeks. The number of apoptotic macrophages peaked at 1 day after laser irradiation and then resolved until 4 weeks. Autophagy was strongly augmented 1 hour after the light therapy, with the formation of autophagolysosomes. LAM-Ce6 photoactivation increased the terminal deoxynucleotidyl transferase dUTP (deoxyuridine triphosphate) nick end labeling/RAM11 (rabbit monocyte/macrophage antibody)- and MerTK (c-Mer tyrosine kinase)-positive cells in the plaques, suggesting enhanced efferocytosis. In line with inflammation resolution, photoactivation reduced the plaque burden through fibrotic replacement via the TGF (transforming growth factor)-β/CTGF (connective tissue growth factor) pathway. Optical coherence tomography-near-infrared fluorescence imaging-guided macrophage Dectin-1-targetable photoactivation could induce the transition of macrophage/lipid-rich plaques into collagen-rich lesions through autophagy-mediated inflammation resolution and TGF-β-dependent fibrotic replacement. This novel strategy offers a new opportunity for the catheter-based theranostic strategy.

Safety evaluation of saffron extracts in early and established atherosclerotic New Zealand white rabbits.

Previous research has shown that natural medications pose health risks, especially in subjects with comorbidities. This study aimed to evaluate the safety of saffron ethanolic extract (SEE) administration in early and established atherosclerotic rabbits. Rabbits were given a high-cholesterol diet (HCD) for 4 and 8 weeks to induce early and established atherosclerosis respectively, and then they were treated with 50 and 100 mg/kg/day SEE. The body weight of the animals was recorded. Blood samples were collected at baseline, pre-treatment, and post-treatment for hematological studies, lipid profiles, and biochemical profiles. Tissue specimens of the vital organs were subjected to histological examination. The above parameters were significantly altered post-intervention with 4 and 8 weeks of HCD. No significant differences in body weight were observed in all the groups post-treatment with 50 and 100mg/kg of SEE compared to pre-treatment. However, low-density lipoprotein cholesterol, total cholesterol, serum urea, and glucose significantly decreased post-treatment with 50 and 100mg/kg/day SEE compared to pre-treatment in early and established atherosclerosis groups. Hematological parameters that were affected post-intervention with HCD returned to their baseline values post-treatment with 50 and 100mg/kg/day SEE. There was a significant improvement in the vital organs post-treatment with 50 and 100mg/kg SEE. SEE can safely be administered without causing harmful effects on the hematological, biochemical profiles, and vital organs. Notably, SEE exerts hypolipidemic and hypoglycemic effects on atherosclerotic conditions. Further clinical trials are warranted to ensure the safety of saffron administration in patients with atherosclerosis-related diseases.

Plaque-stabilizing effect of saffron extract in early and advanced atherosclerotic New Zealand white rabbits

Plaque-stabilizing effect of saffron extract in early and advanced atherosclerotic New Zealand white rabbits

Saffron ethanolic extract suppressed biomarkers of endothelial dysfunction in early and advanced atherosclerotic rabbits

Saffron ethanolic extract suppressed biomarkers of endothelial dysfunction in early and advanced atherosclerotic rabbits

Imaging of atherosclerosis with [64Cu]Cu-DOTA-TATE in a translational head-to-head comparison study with [18F]FDG, and Na[18F]F in rabbits

Atherosclerosis is a chronic inflammatory disease of the larger arteries that may lead to cardiovascular events. Identification of patients at highest risk of cardiovascular events is challenging, but molecular imaging using positron emission tomography (PET) may prove useful. The aim of this study was to evaluate and compare head-to-head three different PET tracers. Furthermore, tracer uptake is compared to gene expression alterations of the arterial vessel wall. Male New Zealand White rabbits (control group; n = 10, atherosclerotic group; n = 11) were used for the study. Vessel wall uptake was assessed with the three different PET tracers: [18F]FDG (inflammation), Na[18F]F (microcalcification), and [64Cu]Cu-DOTA-TATE (macrophages), using PET/computed tomography (CT). Tracer uptake was measured as standardized uptake value (SUV), and arteries from both groups were analyzed ex vivo by autoradiography, qPCR, histology, and immunohistochemistry. In rabbits, the atherosclerotic group showed significantly higher uptake of all three tracers compared to the control group [18F]FDG: SUVmean 1.50 ± 0.11 versus 1.23 ± 0.09, p = 0.025; Na[18F]F: SUVmean 1.54 ± 0.06 versus 1.18 ± 0.10, p = 0.006; and [64Cu]Cu-DOTA-TATE: SUVmean 2.30 ± 0.27 versus 1.65 ± 0.16; p = 0.047. Of the 102 genes analyzed, 52 were differentially expressed in the atherosclerotic group compared to the control group and several genes correlated with tracer uptake. In conclusion, we demonstrated the diagnostic value of [64Cu]Cu-DOTA-TATE and Na[18F]F for identifying atherosclerosis in rabbits. The two PET tracers provided information distinct from that obtained with [18F]FDG. None of the three tracers correlated significantly to each other, but [64Cu]Cu-DOTA-TATE and Na[18F]F uptake both correlated with markers of inflammation. [64Cu]Cu-DOTA-TATE was higher in atherosclerotic rabbits compared to [18F]FDG and Na[18F]F.

Gadolinium K-edge angiography with a spectral photon counting CT in atherosclerotic rabbits

PurposeThe purpose of this study was to investigate the feasibility of gadolinium-K-edge-angiography (angio-Gd-K-edge) with gadolinium-based contrast agents (GBCAs) as obtained with spectral photon counting CT (SPCCT) in atherosclerotic rabbits. Materials and methodsSeven atherosclerotic rabbits underwent angio-SPCCT acquisitions with two GBCAs, with similar intravenous injection protocol. Conventional and angio-Gd-K-edge images were reconstructed with the same parameters. Regions of interest were traced in different locations of the aorta and its branches. Hounsfield unit values, Gd concentrations, signal-to-noise (SNR) and contrast-to-noise (CNR) were calculated and compared. The maximum diameter and the diameter of the aorta in regard to atherosclerotic plaques were measured by two observers. Images were subjectively evaluated regarding vessels’ enhancement, artefacts, border sharpness and overall image quality. ResultsIn the analyzable six rabbits, Gd-K-edge allowed visualization of target vessels and no other structures. HU values and Gd concentrations were greatest in the largest artery (descending aorta, 5.6 ± 0.8 [SD] mm), and lowest in the smallest (renal arteries, 2.1 ± 0.3 mm). While greater for conventional images, CNR and SNR were satisfactory for both images (all P < 0.001). For one observer there were no statistically significant differences in either maximum or plaque-diameters (P = 0.45 and all P > 0.05 in post-hoc analysis, respectively). For the second observer, there were no significant differences for images reconstructed with the same parameters (all P < 0.05). All subjective criteria scored higher for conventional images compared to K-edge (all P < 0.01), with the highest scores for enhancement (4.3–4.4 vs. 3.1–3.4). ConclusionWith SPCCT, angio-Gd-K-edge after injection of GBCAs in atherosclerotic rabbits is feasible and allows for angiography-like visualization of small arteries and for the reliable measurement of their diameters.

Ficus deltoidea var. kunstleri Extract Administration in Hypercholesterolaemic, Atherosclerotic Rabbits: Effects on Organ Function, Morphology, and Atherosclerosis Development

Ficus deltoidea (FD) is used in traditional Malay medicine to treat various ailments and has been shown to be safe in toxicity studies. However, the information on the safety and efficacy of FD in the atherosclerosis-induced animal model is limited. This study aims to investigate the safety of FD var. kunstleri (FDK) extract on high cholesterol diet (HCD)-induced atherosclerotic rabbits and its efficacy in treating atherosclerosis. New Zealand White rabbits were randomly divided into two groups: G1 (1% HCD for 4 weeks) and G2 (1% HCD for 8 weeks). Each group was randomised into FDK700 (700 mg FDK/kg/day for G1 and G2), FDK800 (800 mg FDK/kg/day for G2), simvastatin (5 mg/kg/day) and placebo. The body weight, blood pressure, serum biochemistry and histopathological examination were obtained to assess any toxicity signs. Fasting lipid profile, soluble c-reactive protein (sCRP) level and atherosclerotic plaque formation were compared between treated and placebo groups to evaluate treatment efficacy. Results: No significant differences were observed in all safety parameters between the treated and placebo groups (p&lt;0.05). FDK treatment did not show significant differences in all parameters evaluated in both treatment arms. In conclusion, FDK extract up to 800 mg/kg is safe for use in atherosclerotic rabbits. It has neutral effects on lipid profile, inflammation and atherosclerosis formation.

Desipramine enhances the stability of atherosclerotic plaque in rabbits monitored with molecular imaging.

Acid sphingomyelinase (ASM) promotes atherogenesis and acute cardiovascular events. We previously demonstrated ASM inhibitor desipramine attenuated oxidized-LDL-induced macrophage apoptosis in vitro. Here, we aim to determine whether ASM-mediated apoptosis in plaque improves stability in vivo. In this study, rabbits with abdominal aorta balloon injury and a 12-week high-cholesterol diet (HCD) were used to simulate an atherosclerotic plaque model. Atherosclerotic rabbits received oral administration of saline (Control group), atorvastatin (Ator group), or desipramine (DES group). ASM activity and ceramide level were measured by ultra-performance liquid chromatography (UPLC). Plaque morphology was assessed by histochemistry and immunohistochemistry. Apoptosis was evaluated by SPECT/CT imaging of 99mTc-duramycin uptake and TUNEL. We found that increasing ASM activity and ceramide level in atherosclerotic rabbits was abated by additional atorvastatin and desipramine treatment. Meanwhile, the DES and Ator groups were similar in plaque stability, with smaller plaque size, areas of macrophages, higher smooth muscle cell content, and decreased apoptosis and matrix metalloproteinase (MMP) activities relative to the Control group. 99mTc-duramycin uptake of rabbit aorta was significantly higher in Control than in the Normal group, while it was reduced by desipramine and atorvastatin administration. Moreover, the uptake of 99mTc-duramycin positively correlated with apoptotic cell number, macrophage infiltration, and plaque instability. The present study demonstrated that desipramine exerted plaque-stabilizing effects partially by suppressing apoptosis and MMP activity in a rabbit model. And 99mTc-duramycin SPECT/CT imaging allowed noninvasively monitoring of atherosclerotic disease and evaluation of anti-atherosclerotic therapy.

Effects of norepinephrine on plaque hypoxia in atherosclerotic rabbits.

Hypoxia plays a vital role throughout the whole process of atherosclerotic vulnerable plaque formation, which may be induced by a reduced oxygen supply. The vasa vasorum can be affected by norepinephrine (NE) and cause a reduced oxygen supply, ultimately leading to plaque hypoxia. This study aimed to investigate the effects of norepinephrine, which can increase the tension of the vasa vasorum, on plaque hypoxia, evaluated by contrast-enhanced ultrasound imaging. Atherosclerosis (AS) was induced in New Zealand white rabbits by a combination of a cholesterol-rich diet and aortic balloon dilation. After the atherosclerotic model was well established, NE was intravenously administered three times per day for 2 weeks. Contrast-enhanced ultrasound (CEUS) and immunohistochemistry staining were performed to evaluate the expression of hypoxia-inducible factor alpha (HIF-α) and vascular endothelial growth factor (VEGF) in atherosclerotic plaques. The plaque blood flow decreased after long-term norepinephrine administration. The expression of HIF-α and VEGF in atherosclerotic plaques concentrated in the outer medial layers increased, which indicated that NE might cause plaque hypoxia by contraction of the vasa vasorum. Apparent hypoxia of atherosclerotic plaques after long-term NE administration was mainly caused by decreased plaque blood flow due to the contraction of the vasa vasorum and high blood pressure.

Effects of herbal cake-partitioned moxibustion on plasma trimethylamine, trimethylamine-N-oxide, and flavin-containing monooxygenase 3 in atherosclerotic rabbits

Effects of herbal cake-partitioned moxibustion on plasma trimethylamine, trimethylamine-N-oxide, and flavin-containing monooxygenase 3 in atherosclerotic rabbits

The vascular protective effects of trihoney in hypercholesterolemic atherosclerotic rabbits, a comparative study with atorvastatin

ABSTRACT Atherosclerosis is a chronic inflammatory disease of the inner wall of large- and medium-sized arteries. The histopathological lesion of atherosclerosis is the atherosclerotic plaque. This study aimed to investigate the vascular protective effects of trihoney against the development and progression of atherosclerotic plaques. Thirty male New Zealand white (NZW) rabbits were grouped into six groups, comprising five rabbits per group as follows: normal diet (C), normal diet with 0.6 g/kg/day of trihoney (C + H), 1% cholesterol diet (HCD), 1% cholesterol diet with 0.3 g/kg/day of trihoney (HCD+H1), 1% cholesterol diet with 0.6 g/kg/day of trihoney (HCD+H2) and 1% cholesterol diet with 2 mg/kg/day of atorvastatin (HCD+At). Animals were sacrificed after 12 weeks of treatment. Atherosclerotic plaques were quantified, measured and examined using Sudan IV, Hematoxylin and Eosin (H&E), Verhoeff-van Gieson (VGS) and Masson’s trichrome staining techniques. Trihoney resulted in a significant (p < 0.05) reduction in the number of atherosclerotic lesions, tunica intima thickness, and tunica intima/tunica media thickness ratio. Trihoney preserved the orientation of medial elastic tissues and exhibited a plaque stability effect in the form of subendothelial smooth muscle cells (SMCs) recruitment and reduction of collagen deposition in tunica media. Trihoney could be recommended as a protective natural product and a future adjuvant to statins for the management of atherosclerotic plaques.

Abstract 13560: System Gene Regulatory Network-Based Drug Repurposing Combined With Preclinical Molecular Imaging Identifies Anti-Atherosclerotic Properties of Auranofin

Introduction: The identification of new treatments for atherosclerosis (ACVD), a common complex disease, is a daunting task because sets of genes, rather than individual genes, control cell functions. Using systems genetics, our team identified gene regulatory network (GRN42) that is active in the human atherosclerotic arterial wall and is involved in the regulation of foam cell formation. Hypothesis: A network-driven drug repurposing approach combined with rigorous preclinical validation will identify new uses for existing drugs to treat ACVD. Methods: We developed a GRN42-based computational drug repurposing pipeline to infer new uses for existing drugs. Selected compounds were screened by measuring their ability to inhibit foam cell formation in vitro using THP-1-derived macrophages. The in vivo efficacy was validated in ApoE-/- mice fed a western diet by histology and in atherosclerotic rabbits using histology and non-invasive 18 F-FDG PET-MR imaging. Results: 30 candidate compounds were predicted to influence the function of GRN42 and 5 were selected for in vitro screening based on their prediction scores (Figure 1A). As expected, vitamin D reduced cholesteryl esters accumulation in foam cells. Auranofin, and FDA-approved drug for rheumatoid arthritis reduced foam cell formation. As predicted methyl-fasudil had no effect, while nicardipine and flutamide increased foam cell formation (Figure 1B). Auranofin reduced plaque burden in ApoE-/- mice (Figure 1C) and in rabbits reduced lipid accumulation (Figure 1D) and inflammation shown as reduced 18 F-FDG uptake in the arterial wall (Figure 1E). Conclusions: Our results provide robust evidence that a GRN-based computational drug repurposing approach, when combined with robust preclinical validation using translational molecular imaging, can successfully identify new uses of existing drugs for the treatment of ACVD.

Dual-energy CT imaging of atherosclerotic plaque using novel ultrasmall superparamagnetic iron oxide in hyperlipidemic rabbits.

A study using magnetic resonance imaging (MRI) revealed that ultra-small superparamagnetic iron oxide is phagocytosed by macrophages. However, MRI has limitations in obtaining clear images due to its poor spatial and temporal resolutions. To examine whether the use of dual-energy computed tomography (DECT) facilitated the visualization of carboxymethyl-diethylaminoethyl dextran magnetite ultra-small superparamagnetic iron oxide (CMEADM-U) accumulation in arteriosclerotic lesions using hyperlipidemic rabbits. CMEADM-U at 0.5 mmol Fe/kg was administered to Watanabe hereditary atherosclerotic (WHHL) rabbits (n = 6, 24 sections) and New Zealand white (NZW) rabbits (n = 2, 6 sections). After 72 h, DECT was performed to prepare virtual monochromatic images (35 keV, 70 keV) and an iron-based map. Subsequently, the aorta was collected along with hematoxylin and eosin staining, Berlin blue (BB) staining, and RAM11 immunostaining. In the WHHL rabbits, CMEADM-U accumulation was not observed at 70 keV. However, CMEADM-U accumulation consistent with an arteriosclerotic lesion was observed at 35 keV and the iron-based map. On the other hand, in the NZW rabbits, there was no accumulation of CMEADM-U in any images. Further, there were significant differences in the iron-based map value at the site of accumulation among the grades of expression on BB staining and RAM11 immunostaining. In addition, there was a good correlation at 35 kev and iron-based map value (r = 0.42; P < 0.05). DECT imaging for CMEADM-U facilitated the assessment of macrophage accumulation in atherosclerotic lesions in an in vivo study using a rabbit model of induced aortic atherosclerosis.

Effects of Norepinephrine on Renal Cortical and Medullary Blood Flow in Atherosclerotic Rabbits.

The aim of this study was to explore the effect of norepinephrine (NE) on renal cortical and medullary blood flow in atherosclerotic rabbits without renal artery stenosis. Atherosclerosis was induced in 21 New Zealand white rabbits by feeding them a cholesterol-rich diet for 16 weeks. Thirteen healthy New Zealand white rabbits were randomly selected as controls. After atherosclerosis induction, standard ultrasonography was performed to confirm that there was no plaque or accelerated flow at the origin of the renal artery. Contrast-enhanced ultrasound (CEUS) was performed at baseline and during intravenous injection of NE. The degree of contrast enhancement of renal cortex and medulla after the injection of contrast agents was quantified by calculating the enhanced intensity. The serum nitric oxide (NO) level in atherosclerotic rabbits was higher than that in healthy rabbits (299.6±152 vs. 136.5±49.5, P<0.001). The infusion of NE induced a significant increase in the systolic blood pressure (112±14 mmHg vs. 84±9 mmHg, P=0.016) and a significant decrease in the enhanced intensity in renal cortex (17.78±2.07 dB vs. 21.19±2.03 dB, P<0.001) and renal medulla (14.87±1.82 dB vs. 17.14±1.89 dB, P<0.001) during CEUS. However, the enhanced intensity in the cortex and medulla of healthy rabbits after NE infusion showed no significant difference from that at baseline. NE may reduce renal cortical and medullary blood flow in atherosclerotic rabbits without renal artery stenosis, partly by reducing the serum NO level.

Preclinical Evaluation of Coronary Artery Stents.

Coronary artery disease is a major contributor to morbidity and mortality worldwide. While lifestyle changes and medication are the cornerstones of treatment, coronary artery balloon angioplasty and stenting are routinely performed on patients with acute coronary syndromes and chronic coronary artery disease who remain symptomatic with optical medical treatment. Several generations of coronary stents have been developed over recent decades. Balloon angioplasty and stenting are supported by the use of pharmaceutical agents applied onto balloons and the stent surface, either to advance the healing properties of the artery post-intervention or to prevent the formation of restenosis. New devices need to be rigorously tested for safety and efficacy before acceptance into clinical practice; thus, there is a continuing need for reliable and reproducible preclinical methods of stent evaluation. We describe here a pig coronary artery model as well as an atherosclerotic rabbit model for coronary artery stent research and describe basic steps in intravascular imaging and stent histology.

Effect of saffron ethanolic extract on body weight, lipid profile and atherosclerotic lesions in early and established atherosclerotic New Zealand white rabbits

Background and Aims : Dyslipidaemia and obesity play a major role in the development of atherosclerosis. Saffron, an ancient traditional herb has been used before to treat cardiovascular disease but scientific reports on its effect is scarce. This study aims to investigate the effect of saffron ethanolic extract (SEE) on the weight, lipid profile and atherosclerotic lesions in New Zealand white (NZW) rabbits.

Effect of mild moxibustion on SIRT1/NF-κB signaling in atherosclerotic rabbits

To observe the effect of mild moxibustion on blood lipid, histopathological structure of the aortic arch, thoracic aortic silent information regulator 1 (SIRT1)/nuclear factor κB (NF-κB) signaling pathway in atherosclerosis (AS) rabbits, so as to explore its underlying mechanisms in improving AS. Sixty male rabbits were randomly divided into control group (n=12), model group(n=11), mild moxibustion group (n=11), mild moxibustion + blocker (blocker) group (n=12). The AS model was established by feeding the rabbits with high-fat forage for 8 weeks, followed by immune response damage. Mild moxibustion was applied to "Danzhong"(CV17), "Shenque"(CV8) and "Neiguan" (PC6, bilateral) and "Xuehai" (SP10, bilateral) for 30 min, once daily, 3 times a week for 4 weeks. Rabbits of the blocker group received intraperitoneal injection of EX527 (a selective inhibitor of SIRT1, 5 mg·kg-1·d-1) 30 min before moxibustion. Rabbits of the control and model groups were only grabbed and fixed without intervention. After the intervention, the contents of serum triglyceride (TG) and total cholesterol (TC) were determined by enzymatic method, and those of serum low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were determined by colorimetric method. The Sudan Ⅳ staining was employed to observe the histopathological structure of the aortic arch, and Western blot and fluorescence quantitative real time-PCR were used to detect the expressions of SIRT1 and NF-κB proteins and mRNAs in the thoracic aorta, respectively. Compared with the control group, the contents of serum TG, TC and LDL-C and the expression levels of NF-κB protein and mRNA were significantly increased (P<0.01, P<0.05), whereas the content of HDL-C and the expression of SIRT1 mRNA markedly decreased in the model group (P<0.01). After mild moxibustion, the contents of serum TG, TC, and LDL-C and the expression of NF-κB protein and mRNA were significantly down-regulated (P<0.01, P<0.05), while the content of HDL-C and the expression levels of SIRT1 protein and mRNA significantly up-regulated in the mild moxibustion group (P<0.05, P<0.01). There were no significant differences between the blocker and model groups in all the indexes (P>0.05). Compared with the mild moxibustion group, the serum TG, TC, and LDL-C contents and NF-κB protein expression were significantly increased (P<0.01, P<0.05), and HDL-C content and the expression of SIRT1 protein and mRNA significantly decreased (P<0.05, P<0.01) in the blocker group. Sudan Ⅳ staining showed vague structure of the aortic arch with obvious lipid infiltration in the model group, which was relatively milder in the mild moxibustion. Mild-moxibustion can reduce blood lipid levels and endothelial damage in atherosclerotic rabbits, which may be related to its function in regulating SIRT1/NF-κB signaling pathway.

In vivo Evidence of Arterial Dynamic Properties Alteration in Atherosclerotic Rabbit

Objectives: Atherosclerosis severely damages the arterial wall. The aim of this study was to assess in vivo, for the first time, arterial dynamic properties, reactivity, and stiffness in atherosclerotic (ATH) rabbits. Methods: The rabbits were fed with 0.3% cholesterol diet. Femoral artery (FA) or abdominal aorta (AA) diameter was recorded by echotracking, together with blood pressure. Arterial reactivity after local administration of agents and stiffness were measured as diameter or pulsatile diameter changes. Results: FA dilation induced by acetylcholine was reduced in the function of diet duration (9–65 weeks). With mid-term diet duration (35–45 weeks), the dilation to nitroprusside was greatly reduced; the constriction to norepinephrine was reduced but not that to serotonin, thromboxane agonist, or angiotensin II. After 17- and 28-week diet AA and FA stiffness were increased while distensibility was reduced. Arterial stiffness measured by regional pulse wave velocity was unaltered. We observed that after 28-week diet, FA exhibited a stiffened wall at the plaque level and higher distensibility at the upstream site. Discussion/Conclusion: Arterial reactivity and compliance were greatly modified by atherosclerosis, at various degrees dependent on diet duration. ATH rabbit is therefore a suitable model for in vivo investigations of treatments targeting dynamic properties of arterial wall.

Systematically evaluating DOTATATE and FDG as PET immuno-imaging tracers of cardiovascular inflammation

In recent years, cardiovascular immuno-imaging by positron emission tomography (PET) has undergone tremendous progress in preclinical settings. Clinically, two approved PET tracers hold great potential for inflammation imaging in cardiovascular patients, namely FDG and DOTATATE. While the former is a widely applied metabolic tracer, DOTATATE is a relatively new PET tracer targeting the somatostatin receptor 2 (SST2). In the current study, we performed a detailed, head-to-head comparison of DOTATATE-based radiotracers and [18F]F-FDG in mouse and rabbit models of cardiovascular inflammation. For mouse experiments, we labeled DOTATATE with the long-lived isotope [64Cu]Cu to enable studying the tracer’s mode of action by complementing in vivo PET/CT experiments with thorough ex vivo immunological analyses. For translational PET/MRI rabbit studies, we employed the more widely clinically used [68Ga]Ga-labeled DOTATATE, which was approved by the FDA in 2016. DOTATATE’s pharmacokinetics and timed biodistribution were determined in control and atherosclerotic mice and rabbits by ex vivo gamma counting of blood and organs. Additionally, we performed in vivo PET/CT experiments in mice with atherosclerosis, mice subjected to myocardial infarction and control animals, using both [64Cu]Cu-DOTATATE and [18F]F-FDG. To evaluate differences in the tracers’ cellular specificity, we performed ensuing ex vivo flow cytometry and gamma counting. In mice subjected to myocardial infarction, in vivo [64Cu]Cu-DOTATATE PET showed higher differential uptake between infarcted (SUVmax 1.3, IQR, 1.2–1.4, N = 4) and remote myocardium (SUVmax 0.7, IQR, 0.5–0.8, N = 4, p = 0.0286), and with respect to controls (SUVmax 0.6, IQR, 0.5–0.7, N = 4, p = 0.0286), than [18F]F-FDG PET. In atherosclerotic mice, [64Cu]Cu-DOTATATE PET aortic signal, but not [18F]F-FDG PET, was higher compared to controls (SUVmax 1.1, IQR, 0.9–1.3 and 0.5, IQR, 0.5–0.6, respectively, N = 4, p = 0.0286). In both models, [64Cu]Cu-DOTATATE demonstrated preferential accumulation in macrophages with respect to other myeloid cells, while [18F]F-FDG was taken up by macrophages and other leukocytes. In a translational PET/MRI study in atherosclerotic rabbits, we then compared [68Ga]Ga-DOTATATE and [18F]F-FDG for the assessment of aortic inflammation, combined with ex vivo radiometric assays and near-infrared imaging of macrophage burden. Rabbit experiments showed significantly higher aortic accumulation of both [68Ga]Ga-DOTATATE and [18F]F-FDG in atherosclerotic (SUVmax 0.415, IQR, 0.338–0.499, N = 32 and 0.446, IQR, 0.387–0.536, N = 27, respectively) compared to control animals (SUVmax 0.253, IQR, 0.197–0.285, p = 0.0002, N = 10 and 0.349, IQR, 0.299–0.423, p = 0.0159, N = 11, respectively). In conclusion, we present a detailed, head-to-head comparison of the novel SST2-specific tracer DOTATATE and the validated metabolic tracer [18F]F-FDG for the evaluation of inflammation in small animal models of cardiovascular disease. Our results support further investigations on the use of DOTATATE to assess cardiovascular inflammation as a complementary readout to the widely used [18F]F-FDG.