Aortic Tissue Of Patients Research Articles

LPS-LBP complex induced endothelial cell pyroptosis in aortic dissection is associated with gut dysbiosis

Acute aortic dissection (AAD) is the most severe traumatic disease affecting the aorta. Pyroptosis-mediated vascular wall inflammation is a crucial trigger for AAD, and the exact mechanism requires further investigation. In this study, our proteomic analysis showed that Lipopolysaccharide (LPS)-binding protein (LBP) was significantly upregulated in the plasma and aortic tissue of patients with AAD. Further, 16S rRNA sequencing of stool samples suggested that patients with AAD exhibit gut dysbiosis, which may lead to an impaired intestinal barrier and LPS leakage. By comparing with control mice, we found that LBP, including Pyrin Domain Containing Protein3 (NLRP3), the CARD-containing adapter apoptosis-associated speck-like protein (ASC), and Cleaved caspase-1, were upregulated in the AAD aorta, whereas gut intestinal barrier-related proteins were downregulated. Moreover, treated with LBPK95A (an LBP inhibitor) attenuated the incidence of AAD, the expression levels of pyroptosis-related factors, and the extent of vascular pathological changes compared to those in AAD mice. In addition, LPS and LBP treatment of human umbilical vein endothelial cells (HUVECs) activated TLR4 signaling and intracellular reactive oxygen species (ROS) production, which stimulated NLRP3 inflammasome formation and mediated pyroptosis in endothelial cells. Our findings showed that gut dysbiosis mediates pyroptosis by the LPS-LBP complex, thus providing new insights into developing AAD.

Preclinical evaluation of [11C]GW457427 as a tracer for neutrophil elastase

IntroductionNeutrophils are part of the innate immune system and function as a first line of defense against invading microorganisms. Overactivity of the immune system may result in a devastating immuno-inflammation with extensive damage to tissue leading to organ damage and/or failure. The literature suggests several human diseases in which neutrophil elastase (NE) is postulated to be important in the pathophysiology including inflammatory bowel disease (IBD), chronic obstructive pulmonary disorder (COPD), abdominal aortic aneurysms (AAA), breast and lung cancer, and recently also in Sars-cov-2 virus infection (Covid-19). In particular, the lungs are affected by the destructive power of the protease neutrophil elastase (NE). In this paper, we report the pre-clinical development of a selective and specific positron emission tomography (PET) tracer, [11C]GW457427, as an in vivo biomarker for the study of NE, now available for human studies. Methods[11C]GW457427 was produced by methylation of GW447631 using [11C]methyl triflate and GMP validated production and quality control methods were developed. Chemical purity was high with no traces of the precursor GW611437 or other uv-absorbing compounds. A method for the determination of intact [11C]GW457427 in plasma was developed and the binding characteristics were evaluated in vitro and in vivo. An animal model for lung inflammation was used to investigate the specificity and sensitivity of the [11C]GW457427 tracer for neutrophil elastase (NE) in pulmonary inflammation, verified by blockade using two structurally different elastase inhibitors. Results[11C]GW457427 was obtained in approximately 45% radiochemical yield and with a radiochemical purity higher than 98%. Molar activity was in the range 130–360 GBq/μmol. Binding to NE was shown to be highly specific both in vitro and in vivo and a significantly higher uptake of tracer was found in a lipopolysaccharide mouse model of pulmonary inflammation compared with control animals. The uptake in lung tissue measured as standardized uptake value (SUV) strongly correlated with tissue NE content as measured by ELISA. In vitro studies also showed specific tracer binding in aortic tissue of patients with abdominal aorta aneurysm (AAA). The rate of metabolism in rats was appropriate considering the critical balance between available tracer for binding and requirement for blood clearance with about 40% and 20% intact [11C]GW457427 in plasma at 5 and 40 min, respectively. Radioactivity was cleared from blood and organs in control animals with mainly hepatobiliary excretion with distribution in the intestines and the urinary bladder; but without retention of the tracer in healthy organs of interests such as the lung, liver, kidneys or in the cardiovascular system. A dosimetry study in rat indicated that the whole-body effective dose was 2.2 μSv/MBq with bone marrow as the limiting organ. It is estimated that up to five PET-CT investigations could be performed in humans without exceeding a total dose of 10 mSv. Conclusion[11C]GW457427 is a promising in vivo PET-biomarker for NE with high specific binding demonstrated both in vitro and in vivo. A GMP validated production method including quality control has been developed and a microdosing toxicity study performed with no adverse signs. [11C]GW457427 is currently being evaluated in a First-In-Man PET study.

Notch, BMP and WNT/β-catenin network is impaired in endothelial cells of the patients with thoracic aortic aneurysm

Cellular and molecular mechanisms of thoracic aortic aneurysm are still not clear and therapeutic approaches are mostly absent. The role of endothelial cells in aortic wall integrity is emerging from recent studies. Although Notch pathway ensures endothelial development and integrity, and NOTCH1 mutations have been associated with thoracic aortic aneurysms, the role of this pathway in aneurysm remains elusive. The purpose of the present work was to study functions of Notch genes in endothelial cells of patients with sporadic thoracic aortic aneurysm.Aortic endothelial cells were isolated from aortic tissue of patients with thoracic aortic aneurysm and healthy donors. Gene expression of Notch and related BMP and WNT/β-catenin pathways was estimated by qPCR; WNT/β-catenin signaling was studied by TCF-luciferase reporter. To study the stress-response the cells were subjected to laminar shear stress and the expression of corresponding genes was estimated by qPCR.Analyses of mRNA expression of Notch genes, Notch target genes and Notch related pathways showed that endothelial cells of aneurysm patients have dysregulated Notch/BMP/WNT pathways compared to donor cells. Activity of Wnt pathway was significantly elevated in endothelial cells of the patients. Cells from patients had attenuated activation of DLL4, SNAIL1, DKK1 and BMP2 in response to shear stress.In conclusion endothelial cells of the patients with thoracic aortic aneurysm have dysregulated Notch, BMP and WNT/β-catenin related signaling. Shear stress-response and cross-talk between Notch and Wnt pathways that normally ensures aortic integrity and resistance of endothelial cells to stress is impaired in aneurysmal patients.

Participation of Arachidonic Acid Metabolism in the Aortic Aneurysm Formation in Patients with Marfan Syndrome.

Marfan syndrome (MFS) is a pleiotropic genetic disease involving the cardiovascular system where a fibrillin-1 mutation is present. This mutation is associated with accelerated activation of transforming growth factor β (TGFβ1) which contributes to the formation of aneurysms in the root of the aorta. There is an imbalance in the synthesis of thromboxane A2 (TXA2) and prostacyclin, that is a consequence of a differential protein expression of the isoforms of cyclooxygenases (COXs), suggesting an alteration of arachidonic acid (AA) metabolism. The aim of this study was to analyze the participation of AA metabolism associated with inflammatory factors in the dilation and dissection of the aortic aneurysm in patients with MFS. A decrease in AA (p = 0.02), an increase in oleic acid (OA), TGFβ1, tumor necrosis factor alpha (TNFα), prostaglandin E2 (PGE2) (p < 0.05), and COXs activity (p = 0.002) was found. The expressions of phospholipase A2 (PLA2), cytochrome P450 (CYP450 4A), 5-lipoxygenase (5-LOX), COX2 and TXA2R (p < 0.05) showed a significant increase in the aortic aneurysm of patients with MFS compared to control subjects. COX1, 6-keto-prostaglandin 1 alpha (6-keto-PG1α) and 8-isoprostane did not show significant changes. Histological examination of the aortas showed an increase of cystic necrosis, elastic fibers and collagen in MFS. The results suggest that there are inflammatory factors coupled to genetic factors that predispose to aortic endothelial dysfunction in the aortic tissue of patients with MFS. There is a decrease in the percentage of AA, associated with an increase of PLA2, COX2/TXA2R, CYP450 4A, and 5-LOX which leads to a greater synthesis of PGE2 than of 6-keto-PGF1α, thus contributing to the formation of the aortic aneurysm. The evident loss of the homeostasis in these mechanisms confirms that there is a participation of the AA pathway in the aneurysm progression in MFS.

Relationship Between Echocardiographically Evaluated Aortic Stiffness and Prolidase Activity in Aortic Tissue of Patients with Critical Coronary Artery Disease

The aim of this study was to determine the relationship between echocardiographically evaluated aortic stiffness and prolidase activity in aortic tissue of patients with critical coronary occlusion. Thirty six patients with coronary artery disease (CAD) scheduled for CABG and 30 control patients with no CAD proven angiographically were enrolled in this study. Plasma prolidase activities were quantified spectrophotometrically. During performance of the proximal anastomoses in the study group, a piece of aortic tissue was taken by punch and tissue prolidase activity was quantified spectrophotometrically and also evaluated pathologically by prolidase immunostaining. Eventually, the correlation of plasma prolidase activity, aortic tissue prolidase activity and aortic prolidase immunohistochemical staining with aortic stiffness was studied. The correlation of aortic stiffness with aortic tissue prolidase activity (rs= 0.364; p=0.029) and aortic prolidase immunohistochemical staining (rs=0.354; p=0.034) was significant in the study group. However, the correlation of plasma prolidase activity with aortic stiffness was not statistically significant (rs=0.083; p=0.292). Linear regression analysis showed that the aortic stiffness β index was significantly associated with aortic tissue prolidase activity (β=0.354; p=0.034) and statin usage (β=-0.334; 0.047) in the study group. Regression analysis revealed that ATPA and statin use were predictors of aortic stiffness, and API+ was found to be the predictor for ATPA (β=0.449; p=0.006). Aortic tissue prolidase activity was more significant than plasma prolidase activity and aortic tissue prolidase immunohistochemical staining in the relationship with aortic stiffness in the critical CAD group.

SAT0274 IL-9-Producing TH 9 Cells May Participate in Pathogenesis of Takayasu's Arteritis

BackgroundTakayasu's arteritis (TA) is a granulomatous large vessel vasculitis predominantly affecting the aorta and its major division branches. Over the past decades, cell-mediated autoimmunity has been implicated in the pathogenesis...

Manganese supplementation reduces monocyte adhesion to endothelial cells by reducing ROS and downregulating ICAM‐1 independently of MnSOD

Manganese (Mn2+ ) levels have been found to be lower in the plasma and lymphocytes of diabetic patients and in the heart and aortic tissue of patients with atherosclerosis. Studies in our laboratory have shown that Zucker diabetic fatty rats (ZDF) supplemented with Mn2+ had lower cholesterol (25%, p&lt;0.05), ICAM‐1 (17%, p&lt;0.04), and higher adiponectin (38%, p&lt;0.01) levels in blood. Cell culture studies with Human Umbilical Vein Endothelial Cells (HUVECs) showed that Mn2+ supplementation reduces adhesion of monocytes to endothelial cells (ECs). This study examines the mechanisms by which Mn2+ supplementation decreases monocyte adhesion to ECs, a key event in the development of atherosclerosis. HUVECs were treated with Mn2+ (0, 5, 10 μM) for 24 hours, then exposed to high glucose (HG, 25 mM) for another 24 hrs. Results demonstrate that Mn2+ supplementation decreases ICAM‐1 surface (20%, p&lt;0.05) and total expression (65%, p&lt;0.005), MCP‐1 secretion (16%, p&lt;0.05), and ROS levels (21%, p&lt;0.02) in HG‐treated HUVECs. Silencing studies using siRNA against MnSOD showed that similar effects of Mn2+ on ICAM‐1 expression and ROS were observed in MnSOD knockdown HUVECs. This study suggests that Mn2+ supplementation can decrease monocyte adhesion to ECs, and thereby delay progression of atherosclerosis in diabetes, by decreasing ROS, MCP‐1 secretion, and ICAM‐1 expression, independently of MnSOD.Grant Funding Source: NIDDK and Office of Dietary Supplements

Manganese Supplementation Reduces High Glucose-induced Monocyte Adhesion to Endothelial Cells and Endothelial Dysfunction in Zucker Diabetic Fatty Rats

Endothelial dysfunction is a hallmark of increased vascular inflammation, dyslipidemia, and the development of atherosclerosis in diabetes. Previous studies have reported lower levels of Mn(2+) in the plasma and lymphocytes of diabetic patients and in the heart and aortic tissue of patients with atherosclerosis. This study examines the hypothesis that Mn(2+) supplementation can reduce the markers/risk factors of endothelial dysfunction in type 2 diabetes. Human umbilical vein endothelial cells (HUVECs) were cultured with or without Mn(2+) supplementation and then exposed to high glucose (HG, 25 mm) to mimic diabetic conditions. Mn(2+) supplementation caused a reduction in monocyte adhesion to HUVECs treated with HG or MCP-1. Mn(2+) also inhibited ROS levels, MCP-1 secretion, and ICAM-1 up-regulation in HUVECs treated with HG. Silencing studies using siRNA against MnSOD showed that similar results were observed in MnSOD knockdown HUVECs following Mn(2+) supplementation, suggesting that the effect of manganese on monocyte adhesion to endothelial cells is mediated by ROS and ICAM-1, but not MnSOD. To validate the relevance of our findings in vivo, Zucker diabetic fatty rats were gavaged daily with water (placebo) or MnCl2 (16 mg/kg of body weight) for 7 weeks. When compared with placebo, Mn(2+)-supplemented rats showed lower blood levels of ICAM-1 (17%, p < 0.04), cholesterol (25%, p < 0.05), and MCP-1 (28%, p = 0.25). These in vitro and in vivo studies demonstrate that Mn(2+) supplementation can down-regulate ICAM-1 expression and ROS independently of MnSOD, leading to a decrease in monocyte adhesion to endothelial cells, and therefore can lower the risk of endothelial dysfunction in diabetes.

2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the Diagnosis and Management of Patients with Thoracic Aortic Disease

TABLE OF CONTENTSPreamble ……………………………….280 Introduction ………………………281 1.1. Methodology and Evidence Review … . .2811.2. Organization of the Writing Committee …2831.3. Document Review and Approval …… .2831.4. Scope of the Guideline ……………283 1.4.1. Critical Issues …………… . .2831.5. Glossary of Terms and

2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the Diagnosis and Management of Patients With Thoracic Aortic Disease: Executive Summary

2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the Diagnosis and Management of Patients With Thoracic Aortic Disease: Executive Summary

Perforin-secreting killer cell infiltration in the aortic tissue of patients with atherosclerotic aortic aneurysm.

Cell-mediated immunity has been implicated in the pathogenesis of vascular cell injury in patients with atherosclerotic aortic aneurysms. To clarify the immunologic mechanisms involved, we examined the expression of a cytolytic factor, perforin, in infiltrating cells from aortic tissue samples taken from 6 patients with atherosclerotic aortic aneurysms. Immunohistochemical studies showed that the infiltrating cells consisted mainly of macrophages, natural killer (NK) cells, cytotoxic T lymphocytes (CTLs), and T helper cells, and that perforin was expressed in NK cells and CTLs. Immunoelectron microscopic studies demonstrated that the infiltrating cells released massive amounts of perforin directly on to the surface of arterial vascular cells. These findings provide the first direct evidence that some of the infiltrating cells in the aortic tissue consist of killer cells, and strongly suggest that these killer cells, especially NK cells and CTLs, may play a critical role in the vascular cell injury caused by atherosclerotic aortic aneurysm by releasing perforin.

Restricted Usage of T-Cell Receptor Vα-Vβ Genes in Infiltrating Cells in Aortic Tissue of Patients With Takayasu’s Arteritis

Infiltration by perforin-secreting killer lymphocytes, such as T cells and natural killer cells, has been shown to be involved in the pathogenesis of vascular cell damage in Takayasu's arteritis. To investigate the immunological mechanisms involved, especially the nature of T-cell infiltration in Takayasu's arteritis as well as atherosclerosis, we analyzed the expression of T-cell receptor (TCR) Valpha and Vbeta genes in infiltrating cells in the aortic tissue of patients with Takayasu's arteritis and the atherosclerotic aortic aneurysm by polymerase chain reaction (PCR). We also analyzed the expression of cytokine genes by PCR. We found that the repertoires of TCR Valpha as well as Vbeta gene transcripts in Takayasu's arteritis were restricted. The infiltrating cells expressing Valpha2, Valpha16, Valpha17, Vbeta7, and Vbeta13.1 were found in 3 of 4 patients. In contrast, TCR Valpha-Vbeta repertoires in atherosclerotic aortic aneurysm were polyclonal. There was no significant difference in the pattern of cytokine gene expression between the two diseases. The restricted usage of TCR Valpha as well as Vbeta genes by infiltrating T cells in Takayasu's arteritis may indicate that a specific antigen in the aortic tissue was targeted. Our findings provide the evidence that distinct immunological mechanisms are involved in the pathogenesis of Takayasu's arteritis and atherosclerotic aortic aneurysm.

Perforin-secreting killer cell infiltration and expression of a 65-kD heat-shock protein in aortic tissue of patients with Takayasu's arteritis.

Cell-mediated autoimmunity has been strongly implicated in the pathogenesis of vascular cell injury in Takayasu's arteritis. To clarify the immunological mechanisms involved, we examined the expression of a cytolytic factor, perforin in infiltrating cells of aortic tissue samples from seven patients with Takayasu's arteritis. We also examined the expression of a 65-kD heat-shock protein (HSP-65), human leukocyte antigen classes I and II, and intercellular adhesion molecule-1 in the aortic tissue. Immunohistochemical studies showed that the infiltrating cells mainly consisted of gamma delta T lymphocytes, natural killer cells, macrophages, cytotoxic T lymphocytes and T helper cells, and that perforin was expressed in gamma delta T lymphocytes, natural killer cells, and cytotoxic T lymphocytes. In situ hybridization analysis also revealed expression of perforin mRNA in the infiltrating cells. Immunoelectron microscopic studies demonstrated that the infiltrating cells released massive amounts of perforin directly onto the surface of arterial vascular cells. We also found that expression of HSP-65, human leukocyte antigen classes I and II, and intercellular adhesion molecule-1 was strongly induced in the aortic tissue and might facilitate the recognition, adhesion and cytotoxicity of the infiltrating killer lymphocytes. These findings provide the first direct evidence that the infiltrating cells in the aortic tissue mainly consist of killer cells, and strongly suggest that these killer cells, especially gamma delta T lymphocytes, may recognize HSP-65 and play a critical role in the vascular cell injury of Takayasu's arteritis by releasing perforin.