Cardiovascular Disease in Ageing: An Overview on Thoracic Aortic Aneurysm as an Emerging Inflammatory Disease

Who is who within the universe of TREM-like transcripts (TREML)?

The Triggering Receptor Expressed on Myeloid Cells (TREM) family of receptors plays a crucial role in the immune response across various species. Particularly, TREM-1 and TREM-2 have been extensively studied, both in terms of their applications and their expression sites and signaling pathways. However, the same is not observed for the other family members collectively known as TREM-like-transcripts (TREML). The TREML family consists of eight receptors, with TREML1-5 identified in humans and mice, TREML-6 exclusive found in mice, TREML-7 in dogs and horses, and TREML-8 in rabbits and opossums. Despite the limited data available on the TREML members, they have been implicated in different immune and non-immune activities, which have been proposed to display both pro and anti-inflammatory activities, and to influence fundamental biological processes such as coagulation, bone and neurological development. In this review, we have compiled available information regarding the already discovered members of the family and provided foundational framework for understanding the function, localization, and therapeutic potential of all TREML members. Additionally, we hope that this review may shed light on this family of receptors, whose underlying mechanisms are still awaiting elucidation, while emphasizing the need for future studies to explore their functions and potential therapeutic application.

The key role of miRNA in syndromic and sporadic forms of ascending aortic aneurysms as biomarkers and targets of novel therapeutic strategies

Increasing evidence shows that epigenetics also plays a key role in regulating the pathogenetic mechanism of all types of aortic aneurysms. It is well-known that epigenetic factors modulate gene expression. This mechanism appears to be of interest especially knowing the relevance of genetic susceptibility and genetic factors in the complex pathophysiology of aortic aneurysms, and of sporadic forms; in fact, the latter are the result of a close interaction between genetic and modifiable lifestyle factors (i.e., nutrition, smoking, infections, use of drugs, alcohol, sedentary lifestyle, etc.). Epigenetic factors include DNA methylation, post-translational histone modifications, and non-coding RNA. Here, our attention is focused on the role of miRNA in syndromic and sporadic forms of thoracic aortic aneurysms. They could be both biomarkers and targets of novel therapeutic strategies.

Macrophage in Sporadic Thoracic Aortic Aneurysm and Dissection: Potential Therapeutic and Preventing Target

Thoracic aortic aneurysm and dissection (TAAD) is a life-threatening cardiovascular disorder lacking effective clinical pharmacological therapies. The underlying molecular mechanisms of TAAD still remain elusive with participation of versatile cell types and components including endothelial cells (ECs), smooth muscle cells (SMCs), fibroblasts, immune cells, and the extracellular matrix (ECM). The main pathological features of TAAD include SMC dysfunction, phenotypic switching, and ECM degradation, which is closely associated with inflammation and immune cell infiltration. Among various types of immune cells, macrophages are a distinct participator in the formation and progression of TAAD. In this review, we first highlight the important role of inflammation and immune cell infiltration in TAAD. Furthermore, we discuss the role of macrophages in TAAD from the aspects of macrophage origination, classification, and functions. On the basis of experimental and clinical studies, we summarize key regulators of macrophages in TAAD. Finally, we review how targeting macrophages can reduce TAAD in murine models. A better understanding of the molecular and cellular mechanisms of TAAD may provide novel insights into preventing and treating the condition.

Loss of TIMP3, but not TIMP4, exacerbates thoracic and abdominal aortic aneurysm

AIMS

Aorta exhibits regional heterogeneity (structural and functional), while different etiologies for thoracic and abdominal aortic aneurysm (TAA, AAA) are recognized. Tissue inhibitor of metalloproteinases (TIMPs) regulate vascular remodeling through different mechanisms. Region-dependent functions have been reported for TIMP3 and TIMP4 in vascular pathologies. We investigated the region-specific function of these TIMPs in development of TAA versus AAA.

METHODS & RESULTS

TAA or AAA was induced in male and female mice lacking TIMP3 (Timp3-/-), TIMP4 (Timp4-/-) or in wildtype (WT) mice by peri-adventitial elastase application. Loss of TIMP3 exacerbated TAA and AAA severity in males and females, with a greater increase in proteinase activity, smooth muscle cell phenotypic switching post-AAA and -TAA, while increased inflammation was detected in the media post-AAA, but in the adventitia post-TAA. Timp3-/- mice showed impaired intimal barrier integrity post-AAA, but a greater adventitial vasa-vasorum branching post-TAA, which could explain the site of inflammation in AAA versus TAA. Severity of TAA and AAA in Timp4-/- mice was similar to WT mice. In vitro, Timp3 knockdown more severely compromised the permeability of human aortic EC monolayer compared to Timp4 knockdown or the control group. In aneurysmal aorta specimens from patients, TIMP3 expression decreased in the media in AAA, and in adventitial in TAA specimens, consistent with the impact of its loss in AAA versus TAA in mice.

CONCLUSION

TIMP3 loss exacerbates inflammation, adverse remodeling and aortic dilation, but triggers different patterns of remodeling in AAA versus TAA, and through different mechanisms.

Changes in transmural mass transport correlate with ascending thoracic aortic aneurysm diameter in a fibulin-4 E57K knockin mouse model

Thoracic aortic aneurysm is characterized by dilation of the aortic diameter by greater than 50%, which can lead to dissection or rupture. Common histopathology includes extracellular matrix remodeling that may affect transmural mass transport, defined as the movement of fluids and solutes across the wall. We measured in vitro ascending thoracic aorta mass transport in a mouse model with partial aneurysm phenotype penetration due to a mutation in the extracellular matrix protein fibulin-4 [Fbln4E57K/E57K, referred to as MU-A (aneurysm) or MU-NA (no aneurysm)]. To push the aneurysm phenotype, we also included MU mice with reduced levels of lysyl oxidase [Fbln4E57K/E57K;Lox+/-, referred to as MU-XA (extreme aneurysm)] and compared all groups to wild-type (WT) littermates. The phenotype variation allows investigation of how aneurysm severity correlates with mass transport parameters and extracellular matrix organization. We found that MU-NA ascending thoracic aortae have similar hydraulic conductance (Lp) to WT, but 397% higher solute permeability (ω) for 4 kDa FITC-dextran. In contrast, MU-A and MU-XA ascending thoracic aortae have 44-68% lower Lp and similar ω to WT. The results suggest that ascending thoracic aortic aneurysm progression involves an initial increase in ω, followed by a decrease in Lp after the aneurysm has formed. All MU ascending thoracic aortae are longer and have increased elastic fiber fragmentation in the extracellular matrix. There is a negative correlation between diameter and Lp or ω in MU ascending thoracic aortae. Changes in mass transport due to elastic fiber fragmentation could contribute to aneurysm progression or be leveraged for treatment.NEW & NOTEWORTHY Transmural mass transport is quantified in the ascending thoracic aorta of mice with a mutation in fibulin-4 that is associated with thoracic aortic aneurysms. Fluid and solute transport depend on aneurysm severity, correlate with elastic fiber fragmentation, and may be affected by proteoglycan deposition. Transport properties of the ascending thoracic aorta are provided and can be used in computational models. The changes in mass transport may contribute to aneurysm progression or be leveraged for aneurysm treatment.

Reduced Levels of Selenium and Thioredoxin Reductase in the Thoracic Aorta Could Contribute to Aneurysm Formation in Patients with Marfan Syndrome

Marfan syndrome (MFS) is an autosomal dominant disorder caused by a heterozygous mutation of the FBN1 gene. MFS patients present oxidative stress that disturbs redox homeostasis. Redox homeostasis depends in part on the enzymatic antioxidant system, which includes thioredoxin reductase (TrxR) and glutathione peroxidases (GPx), both of which require an adequate concentration of selenium (Se). Therefore, the aim of this study was to determine if Se levels are decreased in the TAA of patients with MFS since this could contribute to the formation of an aneurysm in these patients. The results show that interleukins IL-1β, IL-6 TGF-β1, and TNF-α (p ≤ 0.03), and carbonylation (p ≤ 0.03) were increased in the TAA of patients with MFS in comparison with control subjects, while Se, thiols (p = 0.02), TrxR, and GPx (p ≤ 0.001) were decreased. TLR4 and NOX1 (p ≤ 0.03), MMP9 and MMP2 (p = 0.04) and NOS2 (p < 0.001) were also increased. Therefore, Se concentrations are decreased in the TAA of MFS, which can contribute to a decrease in the activities of TrxR and GPx, and thiol groups. A decrease in the activities of these enzymes can lead to the loss of redox homeostasis, which can, in turn, lead to an increase in the pro-inflammatory interleukins associated with the overexpression of MMP9 and MMP2.

Novel biomarkers associated with thoracic aortic disease

BACKGROUND

Biomarkers might help to improve diagnosis, surveillance and risk stratification of thoracic aortic disease (TAD). We explored the association between a broad spectrum of cardiovascular biomarkers with clinical characteristics and thoracic aortic diameter in TAD patients.

METHODS

Venous blood-samples were obtained in 158 clinically stable TAD patients visiting our outpatient clinic (2017-2020). TAD was defined as a thoracic aortic diameter ≥ 40 mm, or genetic confirmation (hereditary TAD). The cardiovascular panel III of the Olink multiplex platform was used for batch analysis of 92 proteins. A comparison was made between biomarker levels in patients with and without previous aortic dissection and/or surgery, and with and without hereditary TAD. Linear regression analyses were applied to identify (relative, normalized) biomarker concentrations associated with the absolute thoracic aortic diameter (AD_max), and thoracic aortic diameter indexed for body surface area (ID_max).

RESULTS

Median age of study patients was 61.0 (IQR 50.3-68.8) years, 37.3% females. Mean AD_max and ID_max were 43.3 ± 5.4 mm and 21.3 ± 3.3 mm/m². After multivariable adjustment, Matrix Metalloproteinase-3 (MMP-3) and Insulin-like growth factor binding protein 2 (IGFBP-2) showed a significant positive association with AD_max and ID_max, respectively. Patients with previous aortic surgery/dissection had higher N-terminal-pro hormone BNP (NTproBNP) (median 3.67 [IQR 3.01-3.99] vs 2.84 [2.32-3.26], p ≤0.001). Patients with hereditary TAD had higher Trem-like transcript protein 2 (TLT-2) (median 4.64 [IQR 4.45-4.84]) than those with non-heriditary TAD (4.40 [4.17-4.64]; p = 0.00042).

CONCLUSIONS

Among a broad range of biomarkers, MMP-3 and IGFBP-2 were associated with disease severity in TAD patients. The pathophysiological pathways uncovered by these biomarkers, and their potential clinical use warrants further research.

Satralizumab, Novel Interleukine-6 Inhibitor for Preventing Descending Thoracic Aorta Aneurysm Development

BACKGROUND

Descending thoracic aorta aneurysm (dTAA) has increasing incidence and, if left untreated, could lead to death. There is not any study of satralizumab treatment for preventing dTAA formation and progression.

MATERIALS AND METHODS

Forty male 10-week-old Rattus norvegicus were enrolled in the experiment. They were divided into four equal groups: dTAA treated with saline (dTAA-P) and dTAA treated with satralizumab (dTAA-S). One of the control groups was treated with saline (C-P), and the other was treated with satralizumab (C-S). Satralizumab and saline were used once every 2 weeks, subcutaneously 120 mg for 4 weeks. dTA diameter was measured at days 0, 3, 7, 14, 21, and 28.

RESULTS

IL-6 level was measured on the 7th day that showed significantly increased IL-6 serum level in dTAA-P rats compared to C-P. Maximal dTA diameter (%MAD) was obtained at day 14, which was scientifically matched to the aorta aneurysm definition (>50% increase in diameter). From the seventh day, a significant difference in %MAD was observed between dTAA-P and dTAA-S groups. However, the %MAD of these two groups was significantly higher than control groups till the end of the 28th day.

CONCLUSION

Using an IL-6 inhibitor agent to prevent dTAA formation and progression showed promising results. It suggests that using the IL-6 inhibitors in susceptible persons can be considered a lifesaving therapeutic approach.

Single-Cell RNA-Seq Analysis Reveals Macrophages Are Involved in the Pathogenesis of Human Sporadic Acute Type A Aortic Dissection

Macrophages play an important role in the progression of sporadic acute type A aortic dissection (ATAAD). The aim of this study was to characterize the cellular heterogeneity of macrophages in ATAAD tissues by scRNA-seq. Ascending aortic wall tissue from six ATAAD patients and three heart transplant donors was assessed by scRNA-seq and then analyzed and validated by various bioinformatic algorithms and histopathology experiments. The results revealed that the proportion of macrophages in ATAAD tissues (24.51%) was significantly higher than that in normal tissues (13.69%). Among the six macrophage subclusters, pro-inflammatory macrophages accounted for 14.96% of macrophages in the AD group and 0.18% in the normal group. Chemokine- and inflammation-related genes (CCL2, CCL20, S100A8, and S100A9) were expressed more intensively in macrophages in ATAAD tissue than in those in normal tissue. Additionally, intercellular communication analysis and transcription factor analysis indicated the activation of inflammation and degradation of the extracellular matrix in ATAAD tissue. Finally, immunohistochemistry, immunofluorescence, and Western blot experiments confirmed the overexpression of macrophage marker genes (CD68 and CD163) and matrix metalloproteinases (MMP9 and MMP2) in ATAAD tissue. Collectively, our study provides a preliminary evaluation of the role of macrophages in ATAAD, and the results could aid in the development of therapeutic options in the future.

Structural abnormalities in the non-dilated ascending aortic wall of bicuspid aortic valve patients

BACKGROUND

A bicuspid aortic valve (BAV) is the most common congenital cardiac malformation. The development of the aortic valve is closely related to the development of the ascending aorta, associated with structural differences in the bicuspid aorta. Here we describe the non-dilated ascending aortic wall in bicuspid aortic valve patients.

METHODS

BAV (n=41) and tricuspid aortic valve (TAV) (n=18) non-dilated ascending aortic wall samples were studied. We investigated the following features of the aortic wall: vessel wall thickness, endothelial cell morphology, atherosclerosis, and elastic lamellae organization. Medial pathologic features encompassing elastic fiber thinning, fragmentation and degeneration, overall medial degeneration, mucoid extracellular matrix accumulation, and smooth muscle cell nuclei loss were studied. Furthermore, we included apoptosis, periaortic inflammation, and the level of expression of differentiated vascular smooth muscle cells.

RESULTS

The non-dilated BAV ascending aortic wall is characterized by a significantly thinner intimal layer, without features of atherosclerosis (P<.001). The medial layer is significantly thicker (P<.001) with more mucoid extracellular matrix accumulation (P<.001). All other medial pathologic features were more prominent in the TAV (P<.001). The media has significantly less differentiated vascular smooth muscle cells (P<.001) between the neatly regulated elastic lamellae which are thinner in the BAV as compared to the TAV (P<.0001).

CONCLUSIONS

The BAV ascending aorta without dilatation is characterized by a differentiation defect of vascular smooth muscle cells in the media and a significantly thinner intimal layer without overt pathologic features.

Augmentation Index in Patients with Thoracic Aortic Aneurysm: A Matched Case-Control Study

Thoracic aortic aneurysms (TAA) may be associated with complications such as rupture and dissection, which can lead to a fatal outcome. Increased central arterial stiffness has been proposed to be present in patients with TAA compared to unmatched controls. We aimed to assess whether wall properties in patients with TAA are also altered when compared to a matched control group. Applanation tonometry was performed in 74 adults with TAA and 74 sex, age, weight, height, and left ventricular ejection fraction matched controls. Subsequently analysis of the pulse wave was done using the SphygmoCor System. For comparing the two groups, AIx was adjusted to a heart rate of 75/min (AIx@75). 148 1-to-1 matched participants were included in the final model. There was no significant difference in the Alx@75 between the TAA group and the matched control group [mean (SD) of 24.7 (11.2) % and 22.8 (11.2) %, p = 0.240]. Adjusted for known cardiovascular risk factors, there was no association between TAA and AIx@75. Patients with TAA showed comparable arterial wall properties to cardiovascular risk factor matched controls. Since higher arterial stiffness is associated with TAA progression, it remains to be investigated if increased central arterial stiffness is a relevant factor of TAA emergence.

Vascular Aging and Damage in Patients with Iron Metabolism Disorders

Vascular aging is a physiological, multifactorial process that involves every type of vessel, from large arteries to microcirculation. This manifests itself as impaired vasomotor function, altered secretory phenotype, deteriorated intercellular transport function, structural remodeling, and aggravated barrier function between the blood and the vascular smooth muscle layer. Iron disorders, particularly iron overload, may lead to oxidative stress and, among other effects, vascular aging. The elevated transferrin saturation and serum iron levels observed in iron overload lead to the formation of a non-transferrin-bound iron (NTBI) fraction with high pro-oxidant activity. NTBI can induce the production of reactive oxygen species (ROS), which induce lipid peroxidation and mediate iron-related damage as the elements of oxidative stress in many tissues, including heart and vessels' mitochondria. However, the available data make it difficult to precisely determine the impact of iron metabolism disorders on vascular aging; therefore, the relationship requires further investigation. Our study aims to present the current state of knowledge on vascular aging in patients with deteriorated iron metabolism.

Common molecular mechanism and immune infiltration patterns of thoracic and abdominal aortic aneurysms

BACKGROUND

Aortic disease (aortic aneurysm (AA), dissection (AD)) is a serious threat to patient lives. Little is currently known about the molecular mechanisms and immune infiltration patterns underlying the development and progression of thoracic and abdominal aortic aneurysms (TAA and AAA), warranting further research.

METHODS

We downloaded AA (includes TAA and AAA) datasets from the GEO database. The potential biomarkers in TAA and AAA were identified using differential expression analysis and two machine-learning algorithms. The discrimination power of the potential biomarkers and their diagnostic accuracy was assessed in validation datasets using ROC curve analysis. Then, GSEA, KEGG, GO and DO analyses were conducted. Furthermore, two immuno-infiltration analysis algorithms were utilized to analyze the common immune infiltration patterns in TAA and AAA. Finally, a retrospective clinical study was performed on 78 patients with AD, and the serum from 6 patients was used for whole exome sequencing (WES).

RESULTS

The intersection of TAA and AAA datasets yielded 82 differentially expressed genes (DEGs). Subsequently, the biomarkers (CX3CR1 and HBB) were acquired by screening using two machine-learning algorithms and ROC curve analysis. The functional analysis of DEGs showed significant enrichment in inflammation and regulation of angiogenic pathways. Immune cell infiltration analysis revealed that adaptive and innate immune responses were closely linked to AA progression. However, neither CX3CR1 nor HBB was associated with B cell-mediated humoral immunity. CX3CR1 expression was correlated with macrophages and HBB with eosinophils. Finally, our retrospective clinical study revealed a hyperinflammatory environment in aortic disease. The WES study identified disease biomarkers and gene variants, some of which may be druggable.

CONCLUSION

The genes CX3CR1 and HBB can be used as common biomarkers in TAA and AAA. Large numbers of innate and adaptive immune cells are infiltrated in AA and are closely linked to the development and progression of AA. Moreover, CX3CR1 and HBB are highly correlated with the infiltration of immune cells and may be potential targets of immunotherapeutic drugs. Gene mutation research is a promising direction for the treatment of aortic disease.

Expression of TLR4 Is Upregulated in Patients with Sporadic Acute Stanford Type A Aortic Dissection

Sporadic acute Stanford type A aortic dissection (TAAD) is a serious condition that requires urgent treatment to avoid catastrophic consequences. The purpose of the present study was to explore, firstly, whether TLR4-regulated immune signalling molecules were activated in TAAD patients and, secondly, whether TLR4-regulated inflammatory products interleukin-1β (IL-1β) and CC chemokine ligand 5 (CCL5) could be a promising biomarker for diagnosis in patients with TAAD. Full-thickness ascending aortic wall specimens from TAAD patients (n = 12) and control donors (n = 12) were examined for the expression of TLR4 and its major signalling molecules, in terms of immunity and inflammation. Blood samples from TAAD (n = 49) and control patients (n = 53) were collected to detect the circulating plasma cytokine levels of IL-1β and CCL5. We demonstrated that expression levels of TLR4 and its downstream signalling cascade molecules were significantly elevated. Furthermore, receiver operating characteristic curve analyses showed that elevated IL-1β levels and decreased plasma CCL5 may have diagnostic value for TAAD. In summary, this current study suggests a more generalized pattern of inflammation in TAAD. In addition, TLR4-mediated inflammatory product, such as IL-1β and CCL5, could be novel and promising biomarkers with important diagnostic and predictive value in the identification of sporadic TAAD diseases.

The Endothelial Transcription Factor ERG Mediates a Differential Role in the Aneurysmatic Ascending Aorta with Bicuspid or Tricuspid Aorta Valve: A Preliminary Study

The pathobiology of ascending aorta aneurysms (AAA) onset and progression is not well understood and only partially characterized. AAA are also complicated in case of bicuspid aorta valve (BAV) anatomy. There is emerging evidence about the crucial role of endothelium-related pathways, which show in AAA an altered expression and function. Here, we examined the involvement of ERG-related pathways in the differential progression of disease in aortic tissues from patients having a BAV or tricuspid aorta valve (TAV) with or without AAA. Our findings identified ERG as a novel endothelial-specific regulator of TGF-β-SMAD, Notch, and NO pathways, by modulating a differential fibrotic or calcified AAA progression in BAV and TAV aortas. We provided evidence that calcification is correlated to different ERG expression (as gene and protein), which appears to be under control of Notch signaling. The latter, when increased, associated with an early calcification in aortas with BAV valve and aneurysmatic, was demonstrated to favor the progression versus severe complications, i.e., dissection or rupture. In TAV aneurysmatic aortas, ERG appeared to modulate fibrosis. Therefore, we proposed that ERG may represent a sensitive tissue biomarker to monitor AAA progression and a target to develop therapeutic strategies and influence surgical procedures.

Aging Alters the Aortic Proteome in Health and Thoracic Aortic Aneurysm

BACKGROUND

Aging enhances most chronic diseases but its impact on human aortic tissue in health and in thoracic aortic aneurysms (TAA) remains unclear.

METHODS

We employed a human aortic biorepository of healthy specimens (n=17) and those that underwent surgical repair for TAA (n=20). First, we performed proteomics comparing aortas of healthy donors to aneurysmal specimens, in young (ie, <60 years of age) and old (ie, ≥60 years of age) subjects. Second, we measured proteins, via immunoblotting, involved in mitophagy (ie, Parkin) and also mitochondrial-induced inflammatory pathways, specifically TLR (toll-like receptor) 9, STING (stimulator of interferon genes), and IFN (interferon)-β.

RESULTS

Proteomics revealed that aging transformed the aorta both quantitatively and qualitatively from health to TAA. Whereas young aortas exhibited an enrichment of immunologic processes, older aortas exhibited an enrichment of metabolic processes. Immunoblotting revealed that the expression of Parkin directly correlated to subject age in health but inversely to subject age in TAA. In TAA, but not in health, phosphorylation of STING and the expression of IFN-β was impacted by aging regardless of whether subjects had bicuspid or tricuspid valves. In subjects with bicuspid valves and TAAs, TLR9 expression positively correlated with subject age. Interestingly, whereas phosphorylation of STING was inversely correlated with subject age, IFN-β positively correlated with subject age.

CONCLUSIONS

Aging transforms the human aortic proteome from health to TAA, leading to a differential regulation of biological processes. Our results suggest that the development of therapies to mitigate vascular diseases including TAA may need to be modified depending on subject age.

Silicate ions as soluble form of bioactive ceramics alleviate aortic aneurysm and dissection

Aortic aneurysm and dissection (AAD) are leading causes of death in the elderly. Recent studies have demonstrated that silicate ions can manipulate multiple cells, especially vascular-related cells. We demonstrated in this study that silicate ions as soluble form of bioactive ceramics effectively alleviated aortic aneurysm and dissection in both Ang II and β-BAPN induced AAD models. Different from the single targeting therapeutic drug approaches, the bioactive ceramic derived approach attributes to the effect of bioactive silicate ions on the inhibition of the AAD progression through regulating the local vascular microenvironment of aorta systematically in a multi-functional way. The in vitro experiments revealed that silicate ions did not only alleviate senescence and inflammation of the mouse aortic endothelial cells, enhance M2 polarization of mouse bone marrow-derived macrophages, and reduce apoptosis of mouse aortic smooth muscle cells, but also regulate their interactions. The in vivo studies further confirm that silicate ions could effectively alleviate senescence, inflammation, and cell apoptosis of aortas, accomplished with reduced aortic dilation, collagen deposition, and elastin laminae degradation. This bioactive ceramic derived therapy provides a potential new treatment strategy in attenuating AAD progression.

In vivo cyclic induction of the FOXM1 transcription factor delays natural and progeroid aging phenotypes and extends healthspan

The FOXM1 transcription factor exhibits pleiotropic C-terminal transcriptional and N-terminal non-transcriptional functions in various biological processes critical for cellular homeostasis. We previously found that FOXM1 repression during cellular aging underlies the senescence phenotypes, which were vastly restored by overexpressing transcriptionally active FOXM1. Yet, it remains unknown whether increased expression of FOXM1 can delay organismal aging. Here, we show that in vivo cyclic induction of an N-terminal truncated FOXM1 transgene on progeroid and naturally aged mice offsets aging-associated repression of full-length endogenous Foxm1, reinstating both transcriptional and non-transcriptional functions. This translated into mitigation of several cellular aging hallmarks, as well as molecular and histopathological progeroid features of the short-lived Hutchison-Gilford progeria mouse model, significantly extending its lifespan. FOXM1 transgene induction also reinstated endogenous Foxm1 levels in naturally aged mice, delaying aging phenotypes while extending their lifespan. Thus, we disclose that FOXM1 genetic rewiring can delay senescence-associated progeroid and natural aging pathologies.

Syndecan-1 Is Overexpressed in Human Thoracic Aneurysm but Is Dispensable for the Disease Progression in a Mouse Model

Glycosaminoglycans (GAGs) pooling has long been considered as one of the histopathological characteristics defining thoracic aortic aneurysm (TAA) together with smooth muscle cells (SMCs) apoptosis and elastin fibers degradation. However, little information is known about GAGs composition or their potential implication in TAA pathology. Syndecan-1 (SDC-1) is a heparan sulfate proteoglycan that is implicated in extracellular matrix (ECM) interaction and assembly, regulation of SMCs phenotype, and various aspects of inflammation in the vascular wall. Therefore, the aim of this study was to determine whether SDC-1 expression was regulated in human TAA and to analyze its role in a mouse model of this disease. In the current work, the regulation of SDC-1 was examined in human biopsies by RT-qPCR, ELISA, and immunohistochemistry. In addition, the role of SDC-1 was evaluated in descending TAA in vivo using a mouse model combining both aortic wall weakening and hypertension. Our results showed that both SDC-1 mRNA and protein are overexpressed in the media layer of human TAA specimens. RT-qPCR experiments revealed a 3.6-fold overexpression of SDC-1 mRNA (p = 0.0024) and ELISA assays showed that SDC-1 protein was increased 2.3 times in TAA samples compared with healthy counterparts (221 ± 24 vs. 96 ± 33 pg/mg of tissue, respectively, p = 0.0012). Immunofluorescence imaging provided evidence that SMCs are the major cell type expressing SDC-1 in TAA media. Similarly, in the mouse model used, SDC-1 expression was increased in TAA specimens compared to healthy samples. Although its protective role against abdominal aneurysm has been reported, we observed that SDC-1 was dispensable for TAA prevalence or rupture. In addition, SDC-1 deficiency did not alter the extent of aortic wall dilatation, elastin degradation, collagen deposition, or leukocyte recruitment in our TAA model. These findings suggest that SDC-1 could be a biomarker revealing TAA pathology. Future investigations could uncover the underlying mechanisms leading to regulation of SDC-1 expression in TAA.

Integrating Bulk Transcriptome and Single-Cell RNA Sequencing Data Reveals the Landscape of the Immune Microenvironment in Thoracic Aortic Aneurysms

Thoracic aortic aneurysm (TAA) is a life-threatening cardiovascular disease whose formation is reported to be associated with massive vascular inflammatory responses. To elucidate the roles of immune cell infiltration in the pathogenesis underlying TAA, we utilized multiple TAA datasets (microarray data and scRNA-seq data) and various immune-related algorithms (ssGSEA, CIBERSORT, and Seurat) to reveal the landscapes of the immune microenvironment in TAA. The results exhibited a significant increase in the infiltration of macrophages and T cells, which were mainly responsible for TAA formation among the immune cells. To further reveal the roles of immunocytes in TAA, we inferred the intercellular communications among the identified cells of aortic tissues. Notably, we found that in both normal aortic tissue and TAA tissue, the cells that interact most frequently are macrophages, endothelial cells (ECs), fibroblasts, and vascular smooth muscle cells (VSMCs). Among the cells, macrophages were the most prominent signal senders and receivers in TAA and normal aortic tissue. These findings suggest that macrophages play an important role in both the physiological and pathological conditions of the aorta. The present study provides a comprehensive evaluation of the immune cell composition and reveals the intercellular communication among aortic cells in human TAA tissues. These findings improve our understanding of TAA formation and progression and facilitate the development of effective medications to treat these conditions.

Old blood from heterochronic parabionts accelerates vascular aging in young mice: transcriptomic signature of pathologic smooth muscle remodeling

Vascular aging has a central role in the pathogenesis of cardiovascular diseases contributing to increased mortality of older adults. There is increasing evidence that, in addition to the documented role of cell-autonomous mechanisms of aging, cell-nonautonomous mechanisms also play a critical role in the regulation of vascular aging processes. Our recent transcriptomic studies (Kiss T. et al. Geroscience. 2020;42(2):727-748) demonstrated that circulating anti-geronic factors from young blood promote vascular rejuvenation in aged mice. The present study was designed to expand upon the results of this study by testing the hypothesis that circulating pro-geronic factors also contribute to the genesis of vascular aging phenotypes. To test this hypothesis, through heterochronic parabiosis, we determined the extent to which shifts in the vascular transcriptome (RNA-seq) are modulated by the old systemic environment. We reanalyzed existing RNA-seq data, comparing the transcriptome in the aorta arch samples isolated from isochronic parabiont aged (20-month-old) C57BL/6 mice [A-(A); parabiosis for 8 weeks] and young isochronic parabiont (6-month-old) mice [Y-(Y)] and also assessing transcriptomic changes in the aortic arch in young (6-month-old) parabiont mice [Y-(A); heterochronic parabiosis for 8 weeks] induced by the presence of old blood derived from aged (20-month-old) parabionts. We identified 528 concordant genes whose expression levels differed in the aged phenotype and were shifted towards the aged phenotype by the presence of old blood in young Y-(A) animals. Among them, the expression of 221 concordant genes was unaffected by the presence of young blood in A-(Y) mice. GO enrichment analysis suggests that old blood-regulated genes may contribute to pathologic vascular remodeling. IPA Upstream Regulator analysis (performed to identify upstream transcriptional regulators that may contribute to the observed transcriptomic changes) suggests that the mechanism of action of pro-geronic factors present in old blood may include inhibition of pathways mediated by SRF (serum response factor), insulin-like growth factor-1 (IGF-1) and VEGF-A. In conclusion, relatively short-term exposure to old blood can accelerate vascular aging processes. Our findings provide additional evidence supporting the significant plasticity of vascular aging and the existence of circulating pro-geronic factors mediating pathological remodeling of the vascular smooth muscle cells and the extracellular matrix.

Dexamethasone attenuated thoracic aortic aneurysm and dissection in vascular smooth muscle cell Tgfbr2 disrupted mice with CCL8 suppression

NEW FINDINGS

What is the central question of this study? The aim of this study was to investigate the relationship of CCL8 and the thoracic aortic aneurysm and dissection (TAAD) formation in postnatal mice with vascular smooth muscle cell (VSMC) Tgfbr2 disruption and whether dexamethasone could be a potential treatment. What is the main finding and its importance? CCL8 was associated with the formation of TAAD in VSMC Tgfbr2 disrupted mice. Dexamethasone reduced TAAD formation and inhibited MAPK (p-p38) and NF-κB (p-p65) signaling pathways. CCL8 might be an important promoter in aortic inflammation. DEX provided potential therapeutic effects in TAAD treatment.

ABSTRACT

Aortic inflammation plays a vital role in initiation and progression of thoracic aortic aneurysm and dissection (TAAD). The disturbance of transforming growth factor-β (TGF-β) signaling pathway is believed to be one of the pathogenic mechanisms of TAAD. Initially, Myh11-CreER^T2 .Tgfbr2^f/f male mice were used to build TAAD mice model. And bioinformatics analyses revealed the enriched inflammatory signal pathways and upregulated chemokine CCL8. So we hypothesized that vascular smooth muscle cell (VSMC) Tgfbr2 disruption in postnatal mice resulted in aortic inflammation associated with CCL8 secretion. Then real-time quantitative PCR and serum ELISA results confirmed that CCL8 expression began to increase after VSMC Tgfbr2 disruption. Next, we cultured mouse thoracic aortas ex vivo, and observed that the protein expressions of CCL8 in culture supernatants were increased by ELISA. Subsequently, the co-localization of CCL8 with α-smooth muscle actin (α-SMA) orCD68 was found significantly increased by immunofluorescence. Then, dexamethasone (DEX) was used to treat TAAD in VSMC Tgfbr2 disrupted mice The results of histochemical, immunofluorescence and immunohistochemical staining indicated that DEX therapy reduced CCL8 secretion, inflammatory cell recruitment, aortic medial thickening, elastic fiber fragmentating, extracellular matrix degradation, contractile apparatus impairment, thereby ameliorated TAAD formation. Western blot showed that MAPK and NF-κB signaling pathways in aorta were overactivated after VSMC Tgfbr2 disruption, but inhibited by DEX therapy. Altogether, CCL8 might be an important promoter in TAAD formation of VSMC Tgfbr2 disrupted mice. And DEX provided potential therapeutic effects in TAAD treatment. This article is protected by copyright. All rights reserved.

Ageing causes an aortic contractile dysfunction phenotype by targeting the expression of members of the extracellular signal-regulated kinase pathway

The extracellular signal-regulated kinase (ERK) pathway is a well-known regulator of vascular smooth muscle cell proliferation, but it also serves as a regulator of caldesmon, which negatively regulates vascular contractility. This study examined whether aortic contractile function requires ERK activation and if this activation is regulated by ageing. Biomechanical experiments revealed that contractile responses to the alpha1-adrenergic agonist phenylephrine are attenuated specifically in aged mice, which is associated with downregulation of ERK phosphorylation. ERK inhibition attenuates phenylephrine-induced contractility, indicating that the contractile tone is at least partially ERK-dependent. To explore the mechanisms of this age-related downregulation of ERK phosphorylation, we transfected microRNAs, miR-34a and miR-137 we have previously shown to increase with ageing and demonstrated that in A7r5 cells, both miRs downregulate the expression of Src and paxillin, known regulators of ERK signalling, as well as ERK phosphorylation. Further studies in aortic tissues transfected with miRs show that miR-34a but not miR-137 has a negative effect on mRNA levels of Src and paxillin. Furthermore, ERK phosphorylation is decreased in aortic tissue treated with the Src inhibitor PP2. Increases in miR-34a and miR-137 with ageing downregulate the expression of Src and paxillin, leading to impaired ERK signalling and aortic contractile dysfunction.

Inflammasome Targeted Therapy as Novel Treatment Option for Aortic Aneurysms and Dissections: A Systematic Review of the Preclinical Evidence

Both aortic aneurysm and dissection are life threatening pathologies. In the lack of a conservative medical treatment, the only therapy consists of modifying cardiovascular risk factors and either surgical or endovascular treatment. Like many other cardiovascular diseases, in particular atherosclerosis, aortic aneurysm and dissection have a strong inflammatory phenotype. Inflammasomes are part of the innate immune system. Upon stimulation they form multi protein complexes resulting mainly in activation of interleukin-1β and other cytokines. Considering the gathering evidence, that inflammasomes are decisively involved in the emergence and progression of aortic diseases, inflammasome targeted therapy provides a promising new treatment approach. A systematic review following the PRISMA guidelines on the current preclinical data regarding the potential role of inflammasome targeted drug therapy as novel treatment option for aortic aneurysms and dissections was performed. Included were all rodent models of aortic disease (aortic aneurysm and dissection) evaluating a drug therapy with direct or indirect inhibition of inflammasomes and a suitable control group with the use of the same aortic model without the inflammasome targeted therapy. Primary and secondary outcomes were incidence of aortic disease, aortic rupture, aortic related death, and the maximum aortic diameter. The literature search of MEDLINE (via PubMed), the Web of Science, EMBASE and the Cochrane Central Registry of Registered Trials (CENTRAL) resulted in 8,137 hits. Of these, four studies met the inclusion criteria and were therefore eligible for data analysis. In all of them, targeting of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome effectively reduced the incidence of aortic disease and aortic rupture, and additionally reduced destruction of the aortic wall. Treatment strategies aiming at other inflammasomes could not be identified. In conclusion, inflammasome targeted therapies, more precisely targeting the NLRP3 inflammasome, have shown promising results in rodent models and deserve further investigation in preclinical research to potentially translate them into clinical research for the treatment of human patients with aortic disease. Regarding other inflammasomes, more preclinical research is needed to investigate their role in the pathophysiology of aortic disease.

Protocol Registration: PROSPERO 2021 CRD42021279893, https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021279893

Oxidative Stress in the Pathogenesis of Aorta Diseases as a Source of Potential Biomarkers and Therapeutic Targets, with a Particular Focus on Ascending Aorta Aneurysms

Aorta diseases, such as ascending aorta aneurysm (AsAA), are complex pathologies, currently defined as inflammatory diseases with a strong genetic susceptibility. They are difficult to manage, being insidious and silent pathologies whose diagnosis is based only on imaging data. No diagnostic and prognostic biomarkers or markers of outcome have been known until now. Thus, their identification is imperative. Certainly, a deep understanding of the mechanisms and pathways involved in their pathogenesis might help in such research. Recently, the key role of oxidative stress (OS) on the pathophysiology of aorta disease has emerged. Here, we describe and discuss these aspects by revealing some OS pathways as potential biomarkers, their underlying limitations, and potential solutions and approaches, as well as some potential treatments.

Multi-Omics Profiling in Marfan Syndrome: Further Insights into the Molecular Mechanisms Involved in Aortic Disease

Thoracic aortic aneurysm is a potentially life-threatening disease with a strong genetic contribution. Despite identification of multiple genes involved in aneurysm formation, little is known about the specific underlying mechanisms that drive the pathological changes in the aortic wall. The aim of our study was to unravel the molecular mechanisms underlying aneurysm formation in Marfan syndrome (MFS). We collected aortic wall samples from FBN1 variant-positive MFS patients (n = 6) and healthy donor hearts (n = 5). Messenger RNA (mRNA) expression levels were measured by RNA sequencing and compared between MFS patients and controls, and between haploinsufficient (HI) and dominant negative (DN) FBN1 variants. Immunohistochemical staining, proteomics and cellular respiration experiments were used to confirm our findings. FBN1 mRNA expression levels were highly variable in MFS patients and did not significantly differ from controls. Moreover, we did not identify a distinctive TGF-β gene expression signature in MFS patients. On the contrary, differential gene and protein expression analysis, as well as vascular smooth muscle cell respiration measurements, pointed toward inflammation and mitochondrial dysfunction. Our findings confirm that inflammatory and mitochondrial pathways play important roles in the pathophysiological processes underlying MFS-related aortic disease, providing new therapeutic options.

Role of ferroptosis-related genes in Stanford type a aortic dissection and identification of key genes: new insights from bioinformatic analysis

Stanford type A aortic dissection (TAAD) is one of the most dangerous vascular diseases worldwide, and the mechanisms of its development remain unclear. Further molecular pathology studies may contribute to a comprehensive understanding of TAAD and provide new insights into diagnostic markers and potential therapeutic targets. Recent studies have identified that ferroptosis, a form of cell death, may play a previously unrecognized role in influencing the development of TAAD. In this study, we explored the pathological role of ferroptosis in TAAD by performing bioinformatics analyses. Gene set enrichment analysis (GSEA) showed that the ferroptosis-related gene (FRG) set was significantly different between normal and TAAD aortic samples at an overall level (p < 0.001). Further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses explored the potential functions and pathways of FRG in TAAD. We further identified six key genes (CA9, HMOX1, IL6, CDKN1A, HIF1A, MYC) from differentially expressed FRGs in TAAD by constructing a protein-protein interaction (PPI) network, all key genes were upregulated in TAAD. Four of the key genes (CA9, IL6, CDKN1A, and HIF1A) were demonstrated to be correlated with cigarette smoke extract-induced ferroptosis in aortic vascular smooth muscle cells. These results suggest that ferroptosis is one of the essential pathological processes in the development of TAAD, and some FRGs affect TAAD development by mediating cellular ferroptosis, which provides deepening insights into the molecular mechanisms and potential therapeutic targets of TAAD.

Loss of toll-like receptor 4 ameliorates cardiovascular dysfunction in aged mice

Background

Toll-like receptor 4 (TLR4) is a pattern recognition receptor of the innate immune system. TLR4 contributes to many aging-related chronic diseases. However, whether TLR4 is involved in cardiovascular injury during the aging process has not been investigated.

Methods

The effects of TLR4 on the cardiovascular system of aged mice were investigated in TLR4^−/− mice. An intraperitoneal glucose tolerance test (IPGTT) and insulin sensitivity test (IST) were conducted to evaluate global insulin sensitivity. Echocardiography was used to measure cardiac structure and performance. An isolated artery ring assay was used to measure the vasodilator function of the thoracic aorta. The inflammatory response was reflected by the serum concentration of cytokines.

Results

TLR4 expression increased in the hearts and aortas of mice in an age-dependent manner. Loss of TLR4 increased insulin sensitivity in aged mice. Moreover, loss of TLR4 improved cardiac performance and endothelium-dependent vascular relaxation in aged mice. Importantly, the increases in serum inflammatory cytokines and oxidative stress in the heart and aorta were also inhibited by TLR4 deficiency.

Conclusion

In summary, loss of TLR4 improved cardiac performance and endothelium-dependent vascular relaxation in aged mice. The reduced inflammatory responses and oxidative stress may be the reason for the protective effects of TLR4 deficiency during aging. Our study indicates that targeting TLR4 is a potential therapeutic strategy for preventing aging-related cardiovascular disease.

Inflammasomes in the Pathophysiology of Aortic Disease

Aortic diseases comprise aneurysms, dissections, and several other pathologies. In general, aging is associated with a slow but progressive dilation of the aorta, along with increased stiffness and pulse pressure. The progression of aortic disease is characterized by subclinical development or acute presentation. Recent evidence suggests that inflammation participates causally in different clinical manifestations of aortic diseases. As of yet, diagnostic imaging and surveillance is mainly based on ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI). Little medical therapy is available so far to prevent or treat the majority of aortic diseases. Endovascular therapy by the introduction of covered stentgrafts provides the main treatment option, although open surgery and implantation of synthetic grafts remain necessary in many situations. Because of the risks associated with surgery, there is a need for identification of pharmaceutical targets interfering with the pathophysiology of aortic remodeling. The participation of innate immunity and inflammasome activation in different cell types is common in aortic diseases. This review will thus focus on inflammasome activities in vascular cells of different chronic and acute aortic diseases and discuss their role in development and progression. We will also identify research gaps and suggest promising therapeutic targets, which may be used for future medical interventions.

Preoperative high lymphocyte-to-monocyte ratio is associated with intraoperative type I endoleak in patients with TAA with TEVAR

OBJECTIVES

Various inflammatory factors are closely associated with the incidence of thoracic aortic aneurysms (TAAs). Furthermore, the severity of inflammation is closely related to the absolute value and proportion of each leukocyte subgroup. Only few reports have analyzed the importance of lymphocyte-monocyte ratio (LMR) as a potential inflammatory marker in vascular diseases. Therefore, we aimed to investigate the effect of peripheral blood LMR on thoracic endovascular aortic repair (TEVAR) in patients with TAA.

METHODS

A retrospective study of the clinical data collected in our hospital between January 2016 and January 2021 was performed on 162 patients with TAA treated with TEVAR, based on the inclusion and exclusion criteria for patient selection. Based on whether the patient had the clinical symptoms at admission and the occurrence of type I endoleaks during operation, patients were divided into two groups, respectively: an intraoperative type I endoleak group (n = 34) and a group without intraoperative type I endoleak (n = 128), and a group with clinical symptoms (n = 31) and a group without clinical symptoms (n = 131). The clinical data of these two groups were compared, the free from second intervention rates related to endoleak and the preoperatively LMR of the two groups was calculated. LMR was calculated preoperatively. Receiver-operating characteristic curve analysis was used to determine the cut-off for preoperative LMR values. Based on the cut-off point, patients were divided into a high LMR group (n = 34) and a low LMR group (n = 128). The clinical data of the two groups were compared, and further stratified analysis was performed.

RESULTS

A total of 162 patients were included in the analysis. All patients were successfully implanted with a thoracic aorta stent graft. The preoperative LMR level and postoperative endoleak-related secondary intervention rate were higher in the type I endoleak group than those in the group without intraoperative type I endoleaks. The preoperative C-reactive protein (CRP) level of patients with TAA with clinical symptoms was higher than that of asymptomatic patients. There was a negative correlation between preoperative CRP and LMR levels. In addition, in symptomatic or asymptomatic patients, the LMR level was associated with the occurrence of intraoperative type I endoleaks. After excluding the influence of type of endografts, our results showed that the clinical symptoms did not affect the occurrence of the intraoperative type I endoleak, and patients with intraoperative type I endoleak had a higher rate of postoperative secondary intervention.

CONCLUSION

Patients with TAA with type I endoleaks during TEVAR had an increased rate of secondary intervention related to endoleaks. Patients with TAA with high LMR levels before TEVAR were more likely to have endoleaks during operation.

Dexamethasone reduces the formation of thoracic aortic aneurysm and dissection in a murine model

Thoracic aortic aneurysm and dissection (TAAD) is a life-threatening vascular disease with no effective pharmaceutical therapies currently available. Inflammation plays a key role in the progression of aneurysms. Dexamethasone (DEX), a synthetic glucocorticoid, has showed alleviating effects on cells in vitro from TAAD patients. Here we performed a study aiming at investigating the protective role of DEX in a β-aminopropionitrile monofumarate (BAPN)-induced TAAD mouse model. DEX (dose: 0.04 mg/kg/day) treatment significantly reduced the aortic diameter and inhibited TAAD formation. DEX reduced infiltration of macrophages and neutrophils, apoptosis of vascular smooth muscle cells (VSMCs), expression of metalloproteinase 2/9, and extracellular matrix degradation in BAPN-treated TAAD mice. Furthermore, DEX therapy downregulated the expression of p-p65 in macrophages and VSMCs, which suggested that DEX might ameliorate BAPN-induced TAAD by suppressing NF-κB signaling. Therefore, DEX therapy attenuates the progression of BAPN-induced TAAD murine model and could be used as an effective adjuvant therapy for treating TAAD.

The elevated expression of TLR4 and MMP9 in human abdominal aortic aneurysm tissues and its implication

Background

Toll-like receptor 4 (TLR4) and matrix metalloproteinase 9 (MMP9) have been investigated to play significant roles in the formation of abdominal aortic aneurysm (AAA). But the reports on the expression pattern of TLR4 and MMP9 in human AAA specimens were relatively scant. The aim of this study was to make a detailed analysis of TLR4 and MMP9 expression in situ and their association with clinical parameters involved in human AAA.

Methods

40 AAA specimens were obtained from full-thickness aneurysmal tissues at the maximal dilation area during the open surgical repair, and 8 non-aneurysmal abdominal aortas from transplant donors served as controls. Expression of TLR4 and MMP9 protein was determined by immunohistochemistry.

Results

There were increased levels of TLR4 and MMP9 expression in human AAA tissues. Compared with macrophages or SMCs, lymphocytes showed a higher positive rate of TLR4 and MMP9 staining, and an elevated ratio of high MMP9 expression (all P < 0.05). There existed a significant association between TLR4 and MMP9 expression (r = 0.767, P < 0.001), and both TLR4 and MMP9 levels were statistically related to circulating CRP. Moreover, TLR4 expression in situ indicated a positive correlation with its serum level (r = 0.654, P = 0.006). Multiple analysis revealed that high TLR4 expression in situ was associated with the risk of large AAA (OR = 6.211, 95%CI = 1.226–31.480, P = 0.027), while high MMP9 expression was correlated to the presence of thrombus within AAA (OR = 5.494, 95%CI = 1.181–25.562, P = 0.030), separately compared with their low expression.

Conclusions

This study confirmed the overexpression of TLR4 and MMP9 in human AAA tissues, and their close relationship implying in the pathogenesis of AAA. We further provided evidence that TLR4 had a potential effect on AAA size and MMP9 could influence the occurrence of thrombus within AAA.

Polymorphisms of Pro-Inflammatory IL-6 and IL-1β Cytokines in Ascending Aortic Aneurysms as Genetic Modifiers and Predictive and Prognostic Biomarkers

Background: Previous studies have demonstrated that polymorphisms involved in immune genes can affect the risk, pathogenesis, and outcome of thoracic ascending aortic aneurysms (TAAA). Here, we explored the potential associations of five functional promoter polymorphisms in interleukin-6 (IL-6), IL-1B, IL-1A, IL-18, and Tumor necrosis factor (TNF)A genes with TAAA. Methods: 144 TAAA patients and 150 age/gender matched controls were typed using KASPar assays. Effects on telomere length and levels of TAAA related histopathological and serological markers were analyzed. Results: Significant associations with TAAA risk were obtained for IL-6 rs1800795G>C and IL-1B rs16944C>T SNPs. In addition, the combined rs1800795C/rs16944T genotype showed a synergic effect on TAAA pathogenesis and outcome. The combined rs1800795C/rs16944T genotype was significantly associated with: (a) higher serum levels of both cytokines and MMP-9 and -2; (b) a significant CD3+CD4+CD8+ CD68+CD20+ cell infiltration in aorta aneurysm tissues; (c) a significant shorter telomere length and alterations in telomerase activity. Finally, it significantly correlated with TAAA aorta tissue alterations, including elastic fragmentation, medial cell apoptosis, cystic medial changes, and MMP-9 levels. Conclusions: the combined rs1800795C/rs16944T genotype appears to modulate TAAA risk, pathogenesis, and outcome, and consequently can represent a potential predictive and prognostic TAAA biomarker for individual management, implementation of innovative treatments, and selection of the more proper surgical timing and approaches.

Rare Causes of Arterial Hypertension and Thoracic Aortic Aneurysms-A Case-Based Review

Thoracic aortic aneurysms may result in dissection with fatal consequences if undetected. A young male patient with no relevant familial history, after having been investigated for hypertension, was diagnosed with an ascending aortic aneurysm involving the aortic root and the proximal tubular segment, associated with a septal atrial defect. The patient underwent a Bentall surgery protocol without complications. Clinical examination revealed dorso-lumbar scoliosis and no other signs of underlying connective tissue disease. Microscopic examination revealed strikingly severe medial degeneration of the aorta, with areas of deep disorganization of the medial musculo-elastic structural units and mucoid material deposition. Genetic testing found a variant of unknown significance the PRKG1 gene encoding the protein kinase cGMP-dependent 1, which is important in blood pressure regulation. There may be genetic links between high blood pressure and thoracic aortic aneurysm determinants. Hypertension was found in FBN1 gene mutations encoding fibrillin and in PRKG1 mutations. Possible mechanisms involving the renin-angiotensin system, the role of oxidative stress, osteopontin, epigenetic modifications and other genes are reviewed. Close follow-up and strict hypertension control are required to reduce the risk of dissection. Hypertension, scoliosis and other extra-aortic signs suggesting a connective tissue disease are possible clues for diagnosis.

TLR4 rs1927914 polymorphism contributes to serum TLR4 levels in patients with aortic aneurysm

Toll-like receptor 4 (TLR4) is a crucial regulator of inflammatory reactions and vascular remodeling. Elevated TLR4 expression has been proved to be correlated with an increased risk of aortic aneurysm (AA). This study aimed to explore the influence of TLR4 gene polymorphisms on TLR4 expression levels and its probable functional significance in AA disease. A total of 294 AA patients and 285 controls were enrolled in the study and serum TLR4 levels were detected by ELISA. All the participants were genotyped for two tag-SNPs in TLR4 (rs1927914 in the promoter region and rs11536889 in the 3'-untranslated region) using the KASP method. Relative luciferase activity was measured by the dual-luciferase reporter assay system. The rs1927914 TC, TC/CC genotypes and C allele showed associations with increased serum TLR4 levels in the total population and AA patients (all P<0.05). Further stratified analysis demonstrated that AA subjects with TC or TC/CC genotype of rs1927914 had significantly higher serum levels of TLR4 than those with TT genotype in male, age>60y, hypertension, diabetes, TAA type and size>5.0 cm subgroups (all P<0.05). In binary logistic analysis, rs1927914 TC genotype and dominant model presented significant associations with high TLR4 levels (OR = 1.579 and 1.431, P = 0.020 and 0.049, respectively) after adjusting age, hypertension and diabetes. However, rs11536889 polymorphism had no significant influence on serum TLR4 levels. Regarding rs1927914, luciferase activity of the C allele construct was significantly increased in comparison with the T allele construct (0.589 ± 0.004 vs. 0.340 ± 0.014, P<0.001). Our results provided evidence that rs1927914 polymorphism contributed to serum TLR4 levels, possibly by influencing promoter activity of TLR4, and could be a novel genetic factor in the formation of AA.

Association of Toll-Like Receptor 4 Gene Polymorphisms with Acute Aortic Dissection in a Chinese Han Population

Background

Inflammation may be involved in the pathogenesis of acute aortic dissection (AAD). Toll-like receptor 4 (TLR4) is known to play a critical role in regulating the immune and inflammatory processes. To date, the relationship between genetic variation of TLR4 and AAD is far from clear. The purpose of our study was to illustrate the relevance of TLR4 polymorphisms with the susceptibility to AAD.

Methods

A total of 222 AAD patients and 222 controls were enrolled in this study. Frequency distributions of TLR4 polymorphisms (rs10759932 in the promoter and rs11536889 in the 3′-untranslated region) were determined by the KASP method. Clinical parameters were acquired from subjects' medical records, and serum TLR4 levels were collected from our previously published data.

Results

We found that rs10759932 polymorphism was associated with a reduced risk of AAD in the overall population (CC vs. TT: OR = 0.393, 95%CI = 0.164‐0.939, P = 0.036; recessive model: OR = 0.439, 95%CI = 0.196‐0.984, P = 0.045) and subgroup analyses stratified by sex. The GC genotype and dominant model of rs11536889 conferred a significantly higher risk of AAD compared with GG genotype in female subjects (GC vs. GG: OR = 3.382, 95%CI = 1.051‐10.885, P = 0.041; dominant model: OR = 3.043, 95%CI = 1.041‐8.900, P = 0.042). In addition, a significant interaction between the rs11536889 recessive model and dyslipidemia was observed for an increased risk of AAD (P_interaction = 0.038, OR = 15.229) after the adjustment for potential clinical covariates. We also used the false-positive report probability (FPRP) analysis to validate the significant results. Furthermore, rs11536889 polymorphism could affect the maximal aortic diameters of AAD (P = 0.037), while AAD patients carrying CC genotype of rs10759932 showed lower serum TLR4 levels than TT genotype carriers (P = 0.043).

Conclusions

Our findings provide evidence for the association between TLR4 polymorphisms and AAD susceptibility in a Chinese Han population, which may have some implications for understanding the role of TLR4 in the pathophysiology of AAD.

Receptors for pro-resolving mediators as a therapeutic tool for smooth muscle remodeling-associated disorders

Respiratory airway, blood vessel and intestinal wall remodeling, in which smooth muscle remodeling plays a major role, is a key pathological event underlying the development of several associated diseases, including asthma, cardiovascular disorders (e.g., atherosclerosis, hypertension, and aneurism formation), and inflammatory bowel disease. However, the mechanisms underlying these remodeling processes remain poorly understood. We hypothesize that the creation of chronic inflammation-mediated networks that support and exacerbate the airway, as well as vascular and intestinal wall remodeling, is a crucial pathogenic mechanism governing the development of the associated diseases. The failed inflammation resolution might be one of the causal pathogenic mechanisms. Hence, it is reasonable to assume that applying specialized, pro-resolving mediators (SPMs), acting via cognate G-protein coupled receptors (GPCRs), could potentially be an effective pathway for treating these disorders. However, several obstacles, such as poor understanding of the SPM/receptor signaling pathways, SMP rapid inactivation as well as their complex and costly synthesis, limit their translational potential. In this connection, stable, small-molecule SPM mimetics and receptor agonists have emerged as new, potentially suitable drugs. It has been recently shown in preclinical studies that they can effectively attenuate the manifestations of asthma, atherosclerosis and Crohn's disease. Remarkably, some biased SPM receptor agonists, which cause a signaling response in the desired inflammation pro-resolving direction, revealed similar beneficial effects. These encouraging observations suggest that SPM mimetics and receptor agonists can be applied as a novel approach for the treatment of various chronic inflammation conditions, including airway, vascular and intestinal wall remodeling-associated disorders.

The association between simple renal cyst and aortic diseases: A systematic review and meta-analysis of observational studies

OBJECTIVE

The objective of this meta-analysis of observational studies was to evaluate the association between simple renal cysts (SRC) and presence of aortic pathology such as aortic aneurysms and dissection.

METHODS

We conducted searches in Ovid MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials from January 1960 to August 2019 to identify observational studies that examined the association between SRCs and any aortic diseases, including aortic aneurysms and dissection. Two reviewers independently extracted the data and assessed the risk of bias. The meta-analysis was performed by STATA 14.1.

RESULTS

In total, 11 observational studies with 19 719 participants were included in this meta-analysis. Compared to individuals without SRCs, patients with SRCs had higher odds of abdominal aortic aneurysm (AAA) (adjusted OR = 2.61, 95% CI 2.34-2.91, P < 0.001, I²   = 0%), ascending thoracic aortic aneurysm (TAA) (adjusted OR = 1.98, 95% CI 1.09-3.63, P = 0.03, I²   = 90.1%), descending TAA (adjusted OR = 3.44, 95% CI, 2.67-4.43, P < 0.001, I²   = 0%), type A aortic dissection (AD) (adjusted OR = 1.98, 95% CI 1.32-2.96, P = 0.001, I²   = 12.9%), and type B AD (adjusted OR = 2.55, 95% CI, 1.31-4.96, P = 0.006, I²   = 76.2%). There was a higher average in the sum of diameter of SRCs among AAA compared to patients without AAA (WMD = 19.80 mm, 95% CI 13.92-25.67, P < 0.001, I²   = 63.8%).

CONCLUSION

SRC is associated with higher odds of aortic diseases including AAA, ascending and descending TAA, type A and type B dissection even after adjusting for confounders.

The expression of interleukin 20 increases in plasma and aortic tissues from patients with acute aortic dissection

OBJECTIVE

Acute aortic dissection (AAD) is the most devasting cardiovascular disease associated with high mortality. The occurrence and progression of AAD can be regulated by inflammatory processes, and further understanding of this inflammatory pathogenesis may improve the treatment of AAD. Interleukin 20 (IL-20), as an inflammatory mediator, has been demonstrated to be associated with several inflammatory diseases. However, the association between IL and 20 and AAD is still unknown.

METHODS

Five aortic dissection tissue samples and five control aortic tissue samples were evaluated in our study. The expression of IL-20 and its receptor subunits (IL-20Rα and IL-20Rβ) was detected by immunofluorescence staining. From January 2018 to March 2018, 70 consecutive AAD patients and 25 non-AAD (NAD) patients were enrolled in this study. Diagnosis was based on computed tomography angiography (CTA) results. Blood samples were obtained from the patients on the first day of hospitalization. Plasma IL-20, TNF-α and IL-6 concentrations were evaluated with enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

The expression levels of IL-20 and its receptor subunits (IL-20Rα and IL-20Rβ) were increased in the sites of arterial wall dissection in the AAD patients. In a separate group, the plasma IL-20, TNF-α and IL-6 concentrations were significantly higher in the AAD patients than in the non-AAD patients. Spearman's correlation analysis showed that plasma IL-20 was positively correlated with plasma TNF-α and IL-6, D-dimer, C-reaction protein (CRP), creatinine, fasting blood glucose, systolic blood pressure (SBP), and diastolic blood pressure (DBP). Multiple linear regression revealed that IL-20, in addition to IL-6, glucose, CRP and D-dimer, was independently associated with the presence of AAD.

CONCLUSION

IL-20 was closely associated with the presence of AAD. IL-20 may contribute to the inflammatory pathogenesis of AAD.

Immunological therapeutics in acute aortic syndrome

Acute aortic syndrome is a group of interlinked conditions with common presenting symptoms, including aortic dissection, penetrating atherosclerotic ulcer, and intramural hematoma. Pharmacological management of acute aortic syndrome is a growing area, with key themes to address the underlying inflammatory pathways believed to be the cause. Research into interleukins, matrix metalloproteinases, and granulocyte macrophage colony-stimulating factor are just some of the many immunological properties being investigated and translated into medical therapies. Stem cell experiments may indicate further advances in the pathologies of acute aortic syndrome. The study of pharmacogenomics to improve treatment across different genomes is also a novel area outlined in this paper.

Integrated analysis of immunocyte infiltration and differential gene expression in tricuspid aortic valve-associated thoracic aortic aneurysms

Background

Progressive dilatation is responsible for significant mortality and morbidity in patients with thoracic aortic aneurysms (TAAs). Studies have shown that the development and progression of TAAs are closely related to immune regulatory pathways and genes. Therefore, it is important to understand the immune regulatory mechanisms and biomarkers of TAA dilatation.

Methods

Systematic bioinformatics analysis was applied, including linear models for microarray data (LIMMA) differential expression analyses, principal component analysis (PCA), immunocyte identification, and genetic function enrichment analysis.

Results

Our results showed that both aortic intima-media (AMed) and outer aortic adventitia (AAdv) tissues were closely associated with T cell activation during the process of tricuspid aortic valve (TAV)-associated TAA dilation. Additionally, the degree of infiltration of resting memory CD4+ T cells was linked to both AAdv and AMed vascular dilation. The core regulators PPTRC, IL1B, CD4, CD3G, and IL2RA were also identified and are closely related to resting memory CD4+ T cell infiltration in this pathological process.

Conclusions

The candidate genes PPTRC, IL1B, CD4, CD3G, and IL2RA were involved in the regulation of resting memory CD4 T cell tissue infiltration, which is closely related to the process of AAdv and AMed vascular dilation in TAV patients.

Mean Platelet Volume-to-Platelet Count Ratio, Mean Platelet Volume-to-Lymphocyte Ratio, and Red Blood Cell Distribution Width-Platelet Count Ratio as Markers of Inflammation in Patients with Ascending Thoracic Aortic Aneurysm

OBJECTIVE

Ascending thoracic aortic aneurysm (ATAA), seen in adults, is an important cause of morbidity and mortality. In this study, we aimed to evaluate the levels of mean platelet volume (MPV), mean platelet volume-to-platelet count ratio (MPVPCR), mean platelet volume-to-lymphocyte ratio (MPVLR), and red cell distribution width platelet count ratio (RDWPCR) in patients with thoracic aortic aneurysm.

METHODS

105 patients admitted to the emergency department were diagnosed with thoracic aortic aneurysm between January and December 2014, and 100 healthy individuals were involved in this retrospective study. MPV, MPVLR, MPVPCR and RDWPCRs were calculated at the time of admission.

RESULTS

Platelet and lymphocyte levels were found to be significantly lower in the patient group when compared to the healthy group (P<0.001, P<0.001, respectively), while MPV, MPVPCR, MPVLR and RDWPCR were found to be significantly higher (P<0.001, P<0.001, P<0.001, and P=0.013, respectively). In the patient group, the high-sensitivity C-reactive protein was significantly higher (P<0.001), and the neutrophil (P=0.062) was also higher. In ROC analysis, MPVPCR had the highest sensitivity (80%) and RDWPCR had the highest specificity (72%).

CONCLUSION

The results for MPV, MPVPCR, MPVLR and RDWPCR can be evaluated as useful parameters in the emergency clinical approach in the evaluation of inflammatory activity in ATAA patients. More extensive studies are required to address the role of these parameters in determining the severity of the disease.

The Role of Macrophages in Aortic Dissection

Aortic dissection (AD) is a fatal disease that accounts for a large proportion of aortic-related deaths and has an incidence of about 3–4 per 100,000 individuals every year. Recent studies have found that inflammation plays an important role in the development of AD, and that macrophages are the hub of inflammation in the aortic wall. Aortic samples from AD patients reveal a large amount of macrophage infiltration. The sites of macrophage infiltration and activity vary throughout the different stages of AD, with involvement even in the tissue repair phase of AD. Angiotensin II has been shown to be an important factor in the stimulation of macrophage activity. Stimulated macrophages can secrete metalloproteinases, inflammatory factors and other substances to cause matrix destruction, smooth muscle cell apoptosis, neovascularization and more, all of which destroy the aortic wall structure. At the same time, there are a number of factors that regulate macrophages to reduce the formation of AD and induce the repair of torn aortic tissues. The aim of this review is to take a close look at the roles of macrophages throughout the course of AD disease.

Selective and marked decrease of complement receptor C5aR2 in human thoracic aortic aneurysms: a dysregulation with potential inflammatory effects

Objective

The aetiology of thoracic aortic aneurysm (TAA) is largely unknown, but inflammation is likely to play a central role in the pathogenesis. In this present study, we aim to investigate the complement receptors in TAA.

Methods

Aortic tissue and blood from 31 patients with non-syndromic TAA undergoing thoracic aortic repair surgery were collected. Aortic tissue and blood from 36 patients with atherosclerosis undergoing coronary artery bypass surgery or aortic valve replacement were collected and served as control material. The expression of the complement anaphylatoxin receptors C3aR1, C5aR1 and C5aR2 in aortic tissue were examined by quantitative RT-PCR and C5aR2 protein by immunohistochemistry. Colocalisation of C5aR2 to different cell types was analysed by immunofluorescence. Complement activation products C3bc and sC5b-9 were measured in plasma.

Results

Compared with controls, TAA patients had substantial (73%) downregulated gene expression of C5aR2 as seen both at the mRNA (p=0.005) level and protein (p=0.03) level. In contrast, there were no differences in the expression of C3aR1 and C5aR1 between the two groups. Immunofluorescence examination showed that C5aR2 was colocalised to macrophages and T cells in the aortic media. There were no differences in the degree of systemic complement activation between the two groups.

Conclusion

Our findings suggest downregulation of the C5aR2, regarded to act mainly anti-inflammatory, in electively operated TAA as compared with non-aneurysmatic aortas of patients with aortic stenosis and/or coronary artery disease. This may tip the balance towards a relative increase in the inflammatory responses induced by C5aR1 and thus enhance the inflammatory processes in TAA.

Deregulation of TLR4 signaling pathway characterizes Bicuspid Aortic valve syndrome

Bicuspid aortic valve (BAV) disease is recognized to be a syndrome with a complex and multifaceted pathophysiology. Its progression is modulated by diverse evolutionary conserved pathways, such as Notch-1 pathway. Emerging evidence is also highlighting the key role of TLR4 signaling pathway in the aortic valve pathologies and their related complications, such as sporadic ascending aorta aneurysms (AAA). Consistent with these observations, we aimed to evaluate the role of TLR4 pathway in both BAV disease and its common complication, such as AAA. To this aim, 70 subjects with BAV (M/F 50/20; mean age: 58.8 ± 14.8 years) and 70 subjects with tricuspid aortic valve (TAV) (M/F 35/35; mean age: 69.1 ± 12.8 years), with and without AAA were enrolled. Plasma assessment, tissue and gene expression evaluations were performed. Consistent with data obtained in the previous study on immune clonotypic T and B altered responses, we found reduced levels of systemic TNF-α, IL-1, IL-6, IL-17 cytokines in BAV cases, either in the presence or absence of AAA, than TAV cases (p < 0.0001 by ANOVA test). Interestingly, we also detected reduced levels of s-TLR4 in BAV cases with or without AAA in comparison to the two groups of TAV subjects (p < 0.0001 by ANOVA test). These results may suggest a deregulation in the activity or in the expression of TLR4 signaling pathway in all BAV cases. Portrait of these data is, indeed, the significantly decreased gene expression of inflammatory cytokines and TLR4, in both normal and aneurysmatic tissue samples, from BAV with AAA than TAV with AAA. In conclusion, our study demonstrates that subjects with BAV display a significant deregulation of TLR4 signaling pathway paralleled by a deregulation of Notch-1 pathway, as previously showed. This data suggests that the crosstalk between the Notch-1 and TLR4 signaling pathways may play a crucial role in both physiological embryological development, and homeostasis and functionality of aortic valve in adult life.

Alcohol Consumption and Aortic Root Dilatation: Insights from the Corinthia Study

Aortic diameter and progression to thoracic aortic aneurysm are influenced by several factors. In this study, we investigated the association of alcohol consumption with aortic root and ascending aorta dilatation. In the context of the Corinthia study, we examined 1751 patients with echocardiography. Several demographic and clinical characteristics were recorded. Alcohol consumption was assessed based on a questionnaire of frequency, type, and quantity. Accordingly, patients were categorized as everyday alcohol consumers (EDACs) and as social drinkers (SoD). Everyday alcohol consumers were further categorized to group 1: 0 to 1 drink/d; group 2: 1 to 2 drinks/d; and group 3: ≥3 drinks/d. From the study population, 40% were categorized as EDAC and had an increased aortic root diameter (AoRD) and an elevated AoRD index compared with SoD. Interestingly, there was a stepwise increase in aortic root and ascending aorta diameter according to daily alcohol consumption. Specifically, patients consuming ≥3 drinks of alcohol/d had increased indexed aortic by 1.4 mm/m2 compared with SoD even after adjustment for possible confounders. Daily alcohol consumption is associated with increased aortic root diameter. These findings may have important clinical implications, especially in patients with borderline or dilated aortic root, and merit further investigation.

The bicuspid aortic valve: Is it an immunological disease process?

Bicuspid aortic valves (BAVs) are the most common congenital cardiac condition and are characterized by a structural abnormality whereby the aortic valve is composed of two leaflets instead of being trileaflet. It is linked to an increased risk for a variety of complications of the aorta, many with an immunological pathogenesis. The aim of this study is to review and analyze the literature regarding immunological processes involving BAVs, associated common pathologies, and their incidence in the population. This study will also examine current trends in surgical and therapeutic approaches to treatment and discuss the future direction of BAV treatment.

The interaction effects between TLR4 and MMP9 gene polymorphisms contribute to aortic aneurysm risk in a Chinese Han population

Background

A cross-talk between Toll-like receptor 4 (TLR4) and matrix metalloproteinase 9 (MMP9) plays a vital role in aortic pathophysiology. The objective of this study was to evaluate the interactions between TLR4 and MMP9 polymorphisms in the risk of aortic aneurysm (AA) and its subtypes.

Methods

KASP method was used to detect polymorphisms of TLR4 (rs11536889 and rs1927914) and MMP9 (rs17576) in 472 AA patients and 498 controls. According to location and size, AA patients were further classified into abdominal AA (AAA), thoracic AA (TAA), and large AA (>5.0 cm), small AA(≤5.0 cm), respectively.

Results

The significant interaction effect of TLR4rs1927914 with MMP9rs17576 polymorphisms was observed for the risk of TAA (P_interaction = 0.038, OR = 6.186) and large AA (P_interaction = 0.044, OR = 5.892). There were epistatic effects between TLR4rs1927914 and MMP9rs17576 polymorphisms on the risk of overall AA, AAA, TAA and large AA when they were present together. Moreover, the cumulative effects of the pairwise interaction TLR4rs1927914-MMP9rs17576 were associated with an increased risk of overall AA (P_trend = 0.032) and AAA (P_trend = 0.031).

Conclusions

The novel interaction between TLR4rs1927914 and MMP9rs17576 polymorphisms could increase the risk of AA disease or its subtypes by exerting epistatic and cumulative effects.

Electronic supplementary material

The online version of this article (10.1186/s12872-019-1049-8) contains supplementary material, which is available to authorized users.

New imaging techniques project the cellular and molecular alterations underlying bicuspid aortic valve development

Bicuspid aortic valve (BAV) disease is the most common congenital cardiac malformation associated with an increased lifetime risk and a high rate of surgically-relevant valve deterioration and aortic dilatation. Genomic data revealed that different genes are associated with BAV. A dominant genetic factor for the recent past was the basis to the recommendation for a more extensive aortic intervention. However very recent evidence that hemodynamic stressors and alterations of wall shear stress play an important role independent from the genetic trait led to more conservative treatment recommendations. Therefore, there is a current need to improve the ability to risk stratify BAV patients in order to obtain an early detection of valvulopathy and aortopathy while also to predict valve dysfunction and/or aortic disease development. Imaging studies based on new cutting-edge technologies, such us 4-dimensional (4D) flow magnetic resonance imaging (MRI), two-dimensional (2D) or three-dimensional (3D) speckle-tracking imaging (STI) and computation fluid dynamics, combined with studies demonstrating new gene mutations, specific signal pathways alterations, hemodynamic influences, circulating biomarkers modifications, endothelial progenitor cell impairment and immune/inflammatory response, all detected BAV valvulopathy progression and aortic wall abnormality. Overall, the main purpose of this review article is to merge the evidences of imaging and basic science studies in a coherent hypothesis that underlies and thus projects the development of both BAV during embryogenesis and BAV-associated aortopathy and its complications in the adult life, with the final goal to identifying aneurysm formation/rupture susceptibility to improve diagnosis and management of patients with BAV-related aortopathy.