The ω-3 polyunsaturated fatty acid, eicosapentaenoic acid, attenuates abdominal aortic aneurysm development via suppression of tissue remodeling

Bridging the gap: Navigating the impact of dietary supplements on abdominal aortic aneurysm progression- A systematic review

BACKGROUND

Vitamins D, E, A, B, C, and Omega-3 play crucial roles in modulating inflammatory and oxidative stress pathways, both implicated in abdominal aortic aneurysm (AAA) development. Recent research has explored the potential impact of dietary supplements on AAA progression. The systematic review aims to assess interventional studies investigating the effects of various dietary supplements on the development and severity of abdominal aortic aneurysms.

METHOD

A systematic search using relevant keywords related to abdominal aortic aneurysm and dietary supplements was conducted across four databases (PubMed, Embase, Scopus, and Web of Science). Quality assessment for animal studies employed SYRCLE and the Cochrane Collaboration Risk of Bias Tool for randomized control trials. The study protocol is registered in PROSPERO under the registry code CRD42023455958.

RESULTS

Supplementation with Omega-3, Vitamins A, C, D, E, and the Vitamin B family exhibited positive effects in AAA progression. These supplements contributed to a reduction in AAA diameter, elastin degradation, inflammatory responses, and reactive oxygen species. Additional supplements such as Zinc, methionine, and phytoestrogen also played roles in mitigating AAA progression.

CONCLUSION

The findings of this study underscore the potential role of dietary supplements in the progression of AAA. Predominantly based on animal studies, the results indicate that these supplements can limit AAA progression, primarily evidenced by their ability to mitigate inflammatory processes and oxidative stress pathways.

Similar Distribution between EPA-containing Phosphatidylcholine and Mesenchymal Stem Marker Positive Cells in the Aortic Wall of Abdominal Aortic Aneurysm Model Rat Fed a Low-EPA Content Diet

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by progressive dilation of the abdominal aorta. Previous studies have suggested that dietary components are closely associated with AAA. Among those dietary components, eicosapentaenoic acid (EPA) is considered to have suppressive effects on AAA. In the AAA wall of AAA model animals bred under EPA-rich condition, the distribution of EPA-containing phosphatidylcholine (EPA-PC) has been reported to be similar to that of the markers of mesenchymal stem cells (MSCs) and M2 macrophages. These data suggest that the suppressive effects of EPA on AAA are related to preferential distribution of specific cells in the aortic wall. However, the distribution of EPA-PC in the AAA wall of AAA model animals fed a diet containing small amounts of EPA, which has not been reported to inhibit AAA, has not yet been explored. In the present study, we visualized the distribution of EPA-PCs in the AAA wall of AAA model animals fed a diet containing small amounts of EPA (1.5% EPA in the fatty acid composition) to elucidate the vasoprotective effects of EPA. Positive areas for markers of MSCs were significantly higher in the region where EPA-PC was abundant compared to the regions where EPA-PC was weakly detected, but not for markers of M2 macrophages, matrix metalloproteinase (MMP)-2, and MMP-9. The distribution of MSC markers was similar to that of EPA-PC but not that of M2 macrophages and MMPs. These data suggest preferential incorporation of EPA into MSCs under the conditions used in this study. The incorporation of EPA into certain cells may differ according to dietary conditions, which affect the development of AAA.

Current understanding of macrophages in intracranial aneurysm: relevant etiological manifestations, signaling modulation and therapeutic strategies

Macrophages activation and inflammatory response play crucial roles in intracranial aneurysm (IA) formation and progression. The outcome of ruptured IA is considerably poor, and the mechanisms that trigger IA progression and rupture remain to be clarified, thereby developing effective therapy to prevent subarachnoid hemorrhage (SAH) become difficult. Recently, climbing evidences have been expanding our understanding of the macrophages relevant IA pathogenesis, such as immune cells population, inflammatory activation, intra-/inter-cellular signaling transductions and drug administration responses. Crosstalk between macrophages disorder, inflammation and cellular signaling transduction aggravates the devastating consequences of IA. Illustrating the pros and cons mechanisms of macrophages in IA progression are expected to achieve more efficient treatment interventions. In this review, we summarized the current advanced knowledge of macrophages activation, infiltration, polarization and inflammatory responses in IA occurrence and development, as well as the most relevant NF-κB, signal transducer and activator of transcription 1 (STAT1) and Toll-Like Receptor 4 (TLR4) regulatory signaling modulation. The understanding of macrophages regulatory mechanisms is important for IA patients' clinical outcomes. Gaining insight into the macrophages regulation potentially contributes to more precise IA interventions and will also greatly facilitate the development of novel medical therapy.

Targeting metabolism in aortic aneurysm and dissection: from basic research to clinical applications

Aortic aneurysm and dissection (AAD) are a group of insidious and lethal cardiovascular diseases that characterized by seriously threatening the life and health of people, but lack effective nonsurgical interventions. Alterations in metabolites are increasingly recognized as universal features of AAD because metabolic abnormalities have been identified not only in arterial tissue but also in blood and vascular cells from both patients and animal models with this disease. Over the past few decades, studies have further supported this notion by linking AAD to various types of metabolites such as those derived from gut microbiota or involved in TCA cycle or lipid metabolism. Many of these altered metabolites may contribute to the pathogenesis of AAD. This review aims to illustrate the close association between body metabolism and the occurrence and development of AAD, as well as summarize the significance of metabolites correlated with the pathological process of AAD. This provides valuable insight for developing new therapeutic agents for AAD. Therefore, we present a brief overview of metabolism in AAD biology, including signaling pathways involved in these processes and current clinical studies targeting AAD metabolisms. It is necessary to understand the metabolic mechanisms underlying AAD to provides significant knowledge for AAD diagnosis and new therapeutics for treatment.

Survey of Food Intake in Patients with Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a vascular disease that involves asymptomatic progressive expansion of the abdominal aorta. Aneurysm rupture is associated with a high mortality rate. Dietary conditions may be associated with the development and rupture of AAA. However, the relationship between nutrition and AAA is not completely understood. In this study, a nutrition survey was conducted using a brief self-administered diet history questionnaire (BDHQ) to evaluate the relationship between AAA and dietary habits. One-hundred and twenty-six Japanese people participated in the nutrition survey. Food intake status was analyzed in four groups: the analyzed group-1 (all men), analyzed group-2 (men with smoking history), analyzed group-3 (all women) and analyzed group-4 (women without smoking history). In group-2 and group-3, the intake of citrus fruits was significantly lower in the AAA group than in the non-AAA group. In group-2, the intake of soybean and soybean products was significantly lower in the AAA group than in the non-AAA group. In analyzed group-3, the intake of other vegetables (vegetables except for green and yellow vegetables and soybeans) and seafood was significantly lower in the AAA group than in the non-AAA group. This study suggests that AAA onset may be associated with low intake of fruits, soybeans, vegetables, and seafood.

Dietary therapy in abdominal aortic aneurysm - Insights from clinical and experimental studies

Abdominal aortic aneurysm (AAA) is a prevalent vascular disease with high mortality rates upon rupture. Despite its prevalence in elderly populations, there remain limited treatment options; invasive surgical repair, while risky, is the only therapeutic intervention with proven clinical benefits. Dietary factors have long been suggested to be closely associated with AAA risks, and dietary therapies recently emerged as promising avenues to achieve non-invasive management of a wide spectrum of diseases. However, the role of dietary therapies in AAA remains elusive. In this article, we will summarize the recent clinical and pre-clinical efforts in understanding the therapeutic and mechanistic implications of various dietary patterns and therapeutic approaches in AAA.

Eicosapentaenoic acid is associated with the attenuation of dysfunctions of mesenchymal stem cells in the abdominal aortic aneurysm wall

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by progressive dilation of the aorta which is reportedly associated with inflammation. Previous studies suggested that eicosapentaenoic acid (EPA) has suppressive effects on AAA development via anti-inflammatory activities. However, relationships between the anti-inflammatory effects and the cells in the AAA wall are poorly understood. In this study, we visualized the distribution of EPA-containing phosphatidylcholine (EPA-PC) in the AAA wall. EPA-PC was not ubiquitously distributed in both animal (hypoperfusion-induced AAA model) and human AAA walls, suggesting the preferential incorporation of EPA into certain cells. In the EPA-PC-high region of both animal and human AAAs, mesenchymal stem cell (MSC) marker positive areas were significantly higher than those in the EPA-PC-low region. Matrix metalloproteinase-positive MSCs were significantly lower in the AAA wall of the animal model which was administered EPA-rich fish oil. These data suggest that EPA is associated with the attenuation of MSC dysfunctions, which result in the suppression of AAA development.

Similar distribution of orally administered eicosapentaenoic acid and M2 macrophage marker in the hypoperfusion-induced abdominal aortic aneurysm wall

Abdominal aortic aneurysm (AAA) is an aortic disease in which the aortic diameter is ≥3.0 cm; if left untreated, the aortic wall continues to weaken, resulting in progressive dilatation. Effective therapeutic drugs for AAA patients have not been discovered. Eicosapentaenoic acid (EPA) reportedly attenuates the development of AAA in experimental AAA animal models. However, the underlying mechanism of action is still not totally clear. To understand the mechanism, we visualized the distribution of EPA-containing phosphatidylcholine (PC) in the AAA wall by matrix-assisted laser desorption ionization-mass spectrometry imaging. EPA-containing PC was characteristically distributed in the AAA wall, and the positive area for the M2 macrophage marker was significantly higher in the region where EPA-containing PC was highly detected (region 2) than in the region where EPA-containing PC was poorly detected (region 1). The M1 macrophage marker levels were not different between regions 1 and 2. A comparative observation showed a similar distribution of the M2 macrophage marker and EPA-containing PC. These data suggest the preferential incorporation of EPA into M2 macrophages. Positive areas for matrix metalloproteinase 2 and malondialdehyde in region 2 were significantly lower than those in region 1. The reported suppressive effect of EPA on the development of AAA may be partly attributed to the increased anti-inflammatory property of M2 macrophages.

Omega-3 fatty acids in pathological calcification and bone health

Omega-3 fatty acids (ω-3FAs) such as Docosahexaenoic acid (DHA) and Eicosapentanoic acid (EPA), are active ingredient of fish oil, which have larger health benefits against various diseases including cardiovascular, neurodegenerative, cancers and bone diseases. Substantial studies documented a preventive role of omega-3 fatty acids in pathological calcification like vascular calcification and microcalcification in cancer tissues. In parallel, these fatty acids improve bone quality probably by preventing bone decay and augmenting bone mineralization. This study also addresses that the functions of ω-3FAs not only depend on tissue types, but also work through different molecular mechanisms for preventing pathological calcification in various tissues and improving bone health. PRACTICAL APPLICATIONS: Practical applications of the current study are to improve the knowledge about the supplementation of omega-3 fatty acids. This study infers that supplementation of omega-3 fatty acids aids in bone preservation in elder females at the risk of osteoporosis and also, on the contrary, omega-3 fatty acids interfere with pathological calcification of vascular cells and cancer cells. Omega-3 supplementation should be given to the cardiac patients because of its cardio protective role. In line with this, omega-3 supplementation should be included with chemotherapy for cancer patients as it can prevent osteoblastic potential of breast cancer patients, responsible for pathological mineralization, and blocks off target toxicities. Administration of omega-3 fatty acid with chemotherapy will not only improve survival of cancer patients, but also improve the bone quality. Thus, this study allows a better understanding on omega-3 fatty acids in combating pathological complications such as osteoporosis, vascular calcification, and breast microcalcification.

Inhibition of tissue-nonspecific alkaline phosphatase protects against medial arterial calcification and improves survival probability in the CKD-MBD mouse model

Medial arterial calcification (MAC) is a major complication of chronic kidney disease (CKD) and an indicator of poor prognosis. Aortic overexpression of tissue-nonspecific alkaline phosphatase (TNAP) accelerates MAC formation. The present study aimed to assess whether a TNAP inhibitor, SBI-425, protects against MAC and improves survival probability in a CKD-mineral and bone disorder (MBD) mouse model. CKD-MBD mice were divided in three groups: vehicle, SBI-10, and SBI-30. They were fed a 0.2% adenine and 0.8% phosphorus diet from 14 to 20 weeks of age to induce CKD, followed by a high-phosphorus (0.2% adenine and 1.8% phosphorus) diet for another 6 weeks. At 14-20 weeks of age, mice in the SBI-10 and SBI-30 groups were given 10 and 30 mg/kg SBI-425 by gavage once a day, respectively, while vehicle-group mice were given distilled water as vehicle. Control mice were fed a standard chow (0.8% phosphorus) between the ages of 8 and 20 weeks. Computed tomography imaging, histology, and aortic tissue calcium content revealed that, compared to vehicle animals, SBI-425 nearly halted the formation of MAC. Mice in the control, SBI-10 and SBI-30 groups exhibited 100% survival, which was significantly better than vehicle-treated mice (57.1%). Aortic mRNA expression of Alpl, encoding TNAP, as well as plasma and aortic tissue TNAP activity, were suppressed by SBI-425 administration, whereas plasma pyrophosphate increased. We conclude that a TNAP inhibitor successfully protected the vasculature from MAC and improved survival rate in a mouse CKD-MBD model, without causing any adverse effects on normal skeletal formation and residual renal function. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Pathological Implication of Adipocytes in AAA Development and the Rupture

Abdominal aortic aneurysm (AAA) is a vascular disease that involves the gradual dilation of the abdominal aorta followed by its rupture. AAA is closely associated with weakening of the vascular wall due to oxidative stress, chronic inflammation, and degradation of the extracellular matrix. No effective drug therapy is currently available for preventing aneurysm progression or rupture. Adipocytes in the vascular wall are reportedly closely associated with AAA development and rupture. Fiber degradation in the aneurysm wall is enhanced by increased numbers of adipocytes, and rupture risk may increase as well. Recent studies suggested that appropriate control of adipocytes in the vascular wall may be an important strategy to prevent AAA rupture, and further studies may aid in the establishment of a method for preventing AAA rupture by therapeutic drugs or functional foods. In this review, we summarize adipocyte function and the correlation between AAA and adipocytes.

Arachidonic Acid, but Not Omega-3 Index, Relates to the Prevalence and Progression of Abdominal Aortic Aneurysm in a Population-Based Study of Danish Men

Background

Animal models support dietary omega‐3 fatty acids protection against abdominal aortic aneurysm (AAA), but clinical data are scarce. The sum of red blood cell proportions of the omega‐3 eicosapentaenoic and docosahexaenoic acids, known as omega‐3 index, is a valid surrogate for long‐term omega‐3 intake. We investigated the association between the omega‐3 index and the prevalence and progression of AAA. We also investigated associations between AAA and arachidonic acid, an omega‐6 fatty acid that is a substrate for proinflammatory lipid mediators.

Methods and Results

We obtained blood samples from 498 AAA patients (maximal aortic diameter ≥30 mm) within a population‐based ultrasound‐screening trial in men and from 199 age‐matched controls who screened negative. We determined the fatty acids of red blood cells by gas chromatography. During a median follow‐up of 4.85 years, 141 AAA patients reached criteria for vascular surgical repair. Participants were high consumers of omega‐3 (average omega‐3 index: 7.6%). No significant associations were found for omega‐3 index. In contrast, arachidonic acid in AAA patients was higher than in controls (P<0.001), and individuals in the upper tertile of arachidonic acid at baseline had higher probability of having AAA (odds ratio: 1.309; 95% confidence interval, 1.021–1.678; P=0.033). AAA patients at the upper tertile of arachidonic acid at baseline had a 54% higher risk of needing surgical repair during follow‐up (hazard ratio: 1.544; 95% confidence interval, 1.127–2.114; P=0.007).

Conclusions

Omega‐3 index is unrelated to men with AAA from a country in which fish consumption is customarily high. Arachidonic acid is associated with AAA presence and progression.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00662480.

Age Stratification and Impact of Eicosapentaenoic Acid and Docosahexaenoic Acid to Arachidonic Acid Ratios in Ischemic Stroke Patients

Aim: We focused on the ratios of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) to arachidonic acid (AA) and explored the significance of these ratios relative to clinical characteristics by age in ischemic stroke patients.

Methods: We enrolled patients with acute ischemic stroke who underwent radiological investigations and laboratory examinations, including measurement of serum EPA, DHA, and AA levels, and controls. Patients were classified according to age (< 65, 65–74, and ≥ 75 years) and the tertile of EPA/AA and DHA/AA ratios, and clinical aspects were compared with these factors.

Results: We analyzed 373 patients (age 70.2 ± 13.4 years; 245 males) and 105 controls. Among stroke patients, patients aged < 65 years had the lowest EPA/AA (0.35 ± 0.23, p = 0.006) and DHA/AA (0.73 ± 0.27, p < 0.001) ratios. Compared with controls, patients aged < 65 years showed lower EPA/AA (vs. 0.49 ± 0.25, p < 0.001) and DHA/AA (vs. 0.82 ± 0.26, p = 0.009) ratios. From logistic regression analysis, the EPA/AA (odds ratio 0.18, 95% confidence interval 0.04–0.81, p = 0.026) and DHA/AA (odds ratio 0.09, 95% confidence interval 0.02–0.33, p < 0.001) ratios were inversely related to patients aged < 65 years. According to age-stratified analyses, we found an association of aortic arch calcification with a lower EPA/AA ratio for patients aged ≥ 75 years and an association of multiple infarctions and cerebral white matter lesions with a lower EPA/AA ratio for patients aged 65–74 years (p < 0.05).

Conclusions: The ratios of EPA/AA and DHA/AA could be specific markers for younger stroke patients. The EPA/AA ratio may be related to aortic arch calcification for elderly stroke patients and to multiple infarctions and cerebral white matter disease for middle-aged stroke patients.

Suppression of Wnt Signaling and Osteogenic Changes in Vascular Smooth Muscle Cells by Eicosapentaenoic Acid

Vascular medial calcification is often observed in patients with arteriosclerosis. It is also associated with systolic hypertension, wide pulse pressure, and fluctuation of blood pressure, which results in cardiovascular events. Eicosapentaenoic acid (EPA) has been shown to suppress vascular calcification in previous animal experiments. We investigated the inhibitory effects of EPA on Wnt signaling, which is one of the important signaling pathways involved in vascular calcification. Intake of food containing 5% EPA resulted in upregulation of the mRNA expression of Klotho, an intrinsic inhibitor of Wnt signaling, in the kidneys of wild-type mice. Expression levels of β-catenin, an intracellular signal transducer in the Wnt signaling pathway, were increased in the aortas of Klotho mutant (kl/kl) mice compared to the levels in the aortas of wild-type mice. Wnt3a or BIO, a GSK-3 inhibitor that activates β-catenin signaling, upregulated mRNA levels of AXIN2 and LEF1, Wnt signaling marker genes, and RUNX2 and BMP4, early osteogenic genes, in human aorta smooth muscle cells. EPA suppressed the upregulation of AXIN2 and BMP4. The effect of EPA was cancelled by T0070907, a PPARγ inhibitor. The results suggested that EPA could suppress vascular calcification via the inhibition of Wnt signaling in osteogenic vascular smooth muscle cells via PPARγ activation.

Development of a novel chronic kidney disease mouse model to evaluate the progression of hyperphosphatemia and associated mineral bone disease

Medial arterial calcification (MAC) and renal osteodystrophy are complications of mineral bone disease (MBD) associated with chronic kidney disease (CKD). Our aim was to develop a novel mouse model to investigate the clinical course of CKD-MBD. Eight-week-old C57BL/6 J male mice were assigned to the following groups: the control group, fed a standard chow for 6 or 12 weeks; the CKD-normal phosphorus (NP) group, fed a chow containing 0.2% adenine, with normal (0.8%) phosphorus, for 6 or 12 weeks; and the CKD-high phosphorus (HP) group, fed 6 weeks with the 0.2% adenine/0.8% phosphorus diet, followed by a chow with 1.8% phosphorus for 2 weeks, 4 weeks or 6 weeks. Serum phosphorus was significantly increased in the CKD-HP group, and associated with MAC formation; the volume of calcification increased with longer exposure to the high phosphorus feed. MAC was associated with upregulated expression of runt-related transcription factor 2, alkaline phosphatase, and osteopontin, indicative of osteoblastic trans-differentiation of vascular smooth muscle cells. A significant mineral density depletion of cortical bone was observed. We describe the feasibility of developing a model of CKD-MBD and provide findings of a direct association between elevated serum phosphorus and the formation of MAC and renal osteodystrophy.

Low Serum Levels of EPA are Associated with the Size and Growth Rate of Abdominal Aortic Aneurysm

Aim: Omega-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been reported to reduce the risk of cardiovascular disease. However, whether omega-3 PUFAs are involved in the pathogenesis of abdominal aortic aneurysms (AAA) remains unclear.

Methods: We analyzed 67 consecutive patients admitted for the elective surgical repair of AAA. We investigated the association of serum EPA and DHA levels as well as the EPA/AA ratio with the size of AAA assessed using three-dimensional reconstructed computed tomography images.

Results: Mean patient age was 70 ± 9 years and 60 patients were male. Serum EPA and DHA levels were 75.2 ± 35.7 µg/mL and 146.1 ± 48.5 µg/mL, respectively. EPA/AA ratio was 0.44 ± 0.22, which was lower than those in healthy Japanese subject and equivalent to those in Japanese patients with coronary artery disease as previously reported. Mean of the maximum AAA diameter was 56.4 ± 8.9 mm, and serum EPA levels and EPA/AA ratio negatively correlated with it (r = −0.32 and r = −0.32, respectively). Multiple liner regression analysis showed that EPA levels were significant independent factor contributing to the maximum AAA diameter. Furthermore, low serum EPA levels and low EPA/AA ratio were significantly associated with the growth rate of AAA diameter (r = −0.43 and r = −0.33, respectively).

Conclusion: EPA levels in patients with AAA were relatively low. Low serum EPA levels and EPA/AA ratio were associated with the size and growth rate of AAA.

Impact of omega-3 polyunsaturated fatty acids on vascular function and blood pressure: Relevance for cardiovascular outcomes

AIMS

To overview the effects of omega-3 polyunsaturated fatty acids (PUFA) on blood vessels and blood pressure (BP) and their relevance for cardiovascular prevention.

DATA SYNTHESIS

The importance of omega-3 PUFA for the cardiovascular system has come under the spotlight during the last decades. These fatty acids are present in variable amounts in cell membranes of mammal species, and their content affects a variety of cellular functions. Evidence obtained in animal and human studies suggests that omega-3 PUFA affect many steps of the atherosclerotic process. In blood vessels, omega-3 PUFA improve endothelial function; promote vasodilatation through relaxation of smooth muscle cells; exert antioxidant, anti-inflammatory, and antithrombotic actions; delay development of plaques and increase their stability; and decrease wall stiffening. Omega-3 PUFA might affect BP, and studies conducted with ambulatory monitoring suggest that supplementation with these fatty acids decreases the average 24-h BP levels. This effect on BP is related to the pretreatment membrane content of omega-3 PUFA, and this might explain some inconsistencies among intervention trials. Meta-analyses indicate that omega-3 PUFA have a mild but significant BP lowering effect. While encouraging results were initially obtained with the use of omega-3 PUFA supplements in secondary prevention trials, meta-analyses have not confirmed the ability of these fatty acids to decrease the risk of coronary heart and cerebrovascular disease.

CONCLUSIONS

Omega-3 PUFA are associated with significant improvement in vascular function and lowering of BP. However, the evidence currently supporting the role of these fatty acids in cardiovascular prevention is weak and needs further investigation.

Suppressive effects of dietary EPA-rich fish oil on the degradation of elastin fibers in the aortic wall in nicotine-administered mice

The dietary fish oil can suppress the degradation of elastin fibers in nicotine administered mice.

EPA Prevents the Development of Abdominal Aortic Aneurysms through Gpr-120/Ffar-4

Abdominal aortic aneurysms (AAAs), which commonly occur among elderly individuals, are accompanied by a risk of rupture with a high mortality rate. Although eicosapentaenoic acid (EPA) has been reported to prevent AAA formation, the mechanism by which EPA works on vascular smooth muscle cells is unknown. This study aimed to investigate the mechanism by which orally-administered EPA prevents the formation of severe AAAs that develop in Osteoprotegerin (Opg) knockout (KO) mice. In the CaCl₂-induced AAA model, EPA attenuated the enhanced progression of AAAs in Opg-KO mice, including the increase in aortic diameter with destruction of elastic fibers in the media. Immunohistochemical analyses showed that EPA reduced the phosphorylation of transforming growth factor beta-activated kinase-1/Map3k7 (Tak-1) and c-Jun NH2-terminal kinase (JNK), as well as the expression of Matrix metalloproteinase-9 (Mmp-9) in the media of the aorta. In smooth muscle cell cultures, rh-TRAIL-induced activation of the Tak-1-JNK pathway and increase in Mmp-9 expression were inhibited by EPA. Moreover, GW9508, a specific ligand for G-protein coupled receptor (Gpr)-120/Free fatty acid receptor (Ffar)-4, mimicked the effects of EPA. The effects of EPA were abrogated by knockdown of the Gpr-120/Ffar-4 receptor gene. Our data demonstrate that the Trail-Tak-1-JNK-Mmp-9 pathway is responsible for the enhancement of AAAs in Opg-KO mice, and that EPA inhibits the Tak-1-JNK pathway by activating Gpr-120/Ffar-4, which results in the attenuation of AAA development.

D-series resolvins inhibit murine abdominal aortic aneurysm formation and increase M2 macrophage polarization

The role of resolvins in abdominal aortic aneurysm (AAA) has not been established. We hypothesized that treatment with D-series resolvins (RvD2 or RvD1) would attenuate murine AAA formation through alterations in macrophage polarization and cytokine expression. Male C57/B6 mice (n = 9 per group) 8 to 12 wk old received RvD2 (100 ng/kg/treatment), RvD1 (100 ng/kg/treatment), or vehicle only every third day beginning 3 d before abdominal aortic perfusion with elastase as prevention. Aortas were collected 14 d after elastase perfusion. Cytokine analysis (n = 5 per group) or confocal microscopy (n = 4 per group) was performed. In a separate experiment, RvD2 was provided to mice with small AAAs 3 d after elastase treatment (n = 8 per group). Additionally, apolipoprotein E knockout mice treated with angiotensin II (1000 ng/kg) were treated with RvD2 or vehicle alone (n = 10 per group) in a nonsurgical model of AAA. To determine the effect of RvD2 on macrophage polarization, confocal staining for macrophages, M1 and M2 macrophage subtypes, α-actin, and DAPI was performed. Mean aortic dilation was 96 ± 13% for vehicle-treated mice, 57 ± 9.7% for RvD2-treated mice, and 61 ± 11% for RvD1-treated mice (P < 0.0001). Proinflammatory cytokines macrophage chemotactic protein 1, C-X-C motif ligand 1, and IL-1β were significantly elevated in control animals compared to RvD2- and RvD1-treated animals (P < 0.05), resulting in a reduction of matrix metalloproteinase 2 and 9 activity in resolvin-treated mice in both elastase and angiotensin II models. Treatment of existing small AAAs with RvD2 demonstrated a 25% reduction in aneurysm size at d 14 compared to vehicle alone (P = 0.018). Confocal histology demonstrated a prevalence of M2 macrophages within the aortic medium in mice treated with RvD2. Resolvin D2 exhibits a potent protective effect against experimental AAA formation. Treatment with RvD2 significantly influences macrophage polarization and decreases several important proinflammatory cytokines. Resolvins and the alteration of macrophage polarization represent potential future targets for prevention of AAA.-Pope, N. H., Salmon, M., Davis, J. P., Chatterjee, A., Su, G., Conte, M. S., Ailawadi, G., Upchurch, G. R., Jr. D-series resolvins inhibit murine abdominal aortic aneurysm formation and increase M2 macrophage polarization.

Activation of Endocannabinoid System Is Associated with Persistent Inflammation in Human Aortic Aneurysm

Human aortic aneurysms have been associated with inflammation and vascular remodeling. Since the endocannabinoid system modulates inflammation and tissue remodeling, we investigated its components in human aortic aneurysms. We obtained anterior aortic wall samples from patients undergoing elective surgery for aortic aneurysm or coronary artery disease as controls. Histological and molecular analysis (RT-qPCR) was performed, and endocannabinoid concentration was determined using LC-MRM. Patient characteristics were comparable between the groups except for a higher incidence of arterial hypertension and diabetes in the control group. mRNA level of cannabinoid receptors was significantly higher in aneurysms than in controls. Concentration of the endocannabinoid 2-arachidonoylglycerol was significantly higher, while the second endocannabinoid anandamide and its metabolite arachidonic acid and palmitoylethanolamide were significantly lower in aneurysms. Histology revealed persistent infiltration of newly recruited leukocytes and significantly higher mononuclear cell density in adventitia of the aneurysms. Proinflammatory environment in aneurysms was shown by significant upregulation of M-CSF and PPARγ but associated with downregulation of chemokines. We found comparable collagen-stained area between the groups, significantly decreased mRNA level of CTGF, osteopontin-1, and MMP-2, and increased TIMP-4 expression in aneurysms. Our data provides evidence for endocannabinoid system activation in human aortic aneurysms, associated with persistent low-level inflammation and vascular remodeling.

Dietary Omega-3 Fatty Acids Suppress Experimental Autoimmune Uveitis in Association with Inhibition of Th1 and Th17 Cell Function

Omega (ω)–3 long-chain polyunsaturated fatty acids (LCPUFAs) inhibit the production of inflammatory mediators and thereby contribute to the regulation of inflammation. Experimental autoimmune uveitis (EAU) is a well-established animal model of autoimmune retinal inflammation. To investigate the potential effects of dietary intake of ω-3 LCPUFAs on uveitis, we examined the anti-inflammatory properties of these molecules in comparison with ω-6 LCPUFAs in a mouse EAU model. C57BL/6 mice were fed a diet containing ω-3 LCPUFAs or ω-6 LCPUFAs for 2 weeks before as well as after the induction of EAU by subcutaneous injection of a fragment of human interphotoreceptor retinoid-binding protein emulsified with complete Freund’s adjuvant. Both clinical and histological scores for uveitis were smaller for mice fed ω-3 LCPUFAs than for those fed ω-6 LCPUFAs. The concentrations of the T helper 1 (Th1) cytokine interferon-γ and the Th17 cytokine interleukin-17 in intraocular fluid as well as the production of these cytokines by lymph node cells were reduced for mice fed ω-3 LCPUFAs. Furthermore, the amounts of mRNAs for the Th1- and Th17-related transcription factors T-bet and RORγt, respectively, were reduced both in the retina and in lymph node cells of mice fed ω-3 LCPUFAs. Our results thus show that a diet enriched in ω-3 LCPUFAs suppressed uveitis in mice in association with inhibition of Th1 and Th17 cell function.

Eicosapentaenoic Acid as long-term secondary prevention after ischemic stroke

Background

It is sometimes difficult to choose anti-thrombotic agents for secondary prevention in stroke patients at high bleeding risk. Recently, Eicosapentaenoic Acid (EPA) was reported to reduce the recurrence of stroke in hypercholesterolemic patients without increasing hemorrhagic risk. In this study, we investigated the features of recurrent stroke patients during EPA medication as secondary stroke prevention.

Methods

Following the approval of the ethical committee, stroke patients in the outpatient clinic were consecutively screened and patients who continuously take EPA were enrolled in this study (n = 71, average age 69.7 yo). Blood sample data was adopted from the latest visit or the admission at the stroke recurrence. According to the previous stroke history, all patients were classified into the hemorrhagic stroke (HS) group (n = 10) and the ischemic stroke, including asymptomatic infarction, (IS) group (n = 61).

Result

Any stroke recurrence was not observed in the HS group. Whereas, ischemic stroke recurrence was observed in 6 patients in the IS group, although there was no hemorrhagic stroke recurrence. Recurrent stroke patients showed the higher serum level of cholesterol or the renal dysfunction. The stroke subtype of patients were 2 embolic strokes, 3 atherothrombotic infarctions (two were compromised with renal failure and one had insufficient amount of EPA) and one lacunar infarction (who showed high triglyceride level).

Conclusion

Hemorrhagic stroke was not occurred in our observation of EPA prescribed patients. The clinical features of recurrent stroke patients were the existing complications of dyslipidemia and renal dysfunction.

Micro-CT evaluation of high pressure-decellularized cardiovascular tissues transplanted in rat subcutaneous accelerated-calcification model

We have succeeded in reducing the calcification of acellular aortas or valves in porcine allogeneic system by removing the DNA and phospholipids, but its further reduction is desirable. Here, the calcification of the acellular tissue was evaluated in rat subcutaneous transplantation model which is known as calcification model. Acellular samples prepared by high-hydrostatic pressure (HHP) protocols with different washing media were implanted and the calcification was monitored under micro-computed tomography for 1 and 3 months. The amount of the calcium deposition was quantitatively evaluated by atomic absorption spectroscopy. A cell culture medium showed very good cell removal ability but led to severe calcification at 1 month, and surprisingly the calcium deposition increased as the washing period increased. This calcification was suppressed by removing the DNA fraction with high DNase concentration. On the other hand, the calcification was greatly reduced when washed with saline even at low DNase concentration after 2 weeks washing. These results suggest that the ion species in the washing medium and the residual DNase cooperatively affect the tendency of in vivo calcification, which led us to the possibility of reduced calcification of acellular cardiac tissues.