Oxidative Stress-Related Susceptibility to Aneurysm in Marfan's Syndrome

Genetic Manipulation of Caveolin-1 in a Transgenic Mouse Model of Aortic Root Aneurysm: Sex-Dependent Effects on Endothelial and Smooth Muscle Function

Marfan syndrome (MFS) is a systemic connective tissue disorder stemming from mutations in the gene encoding Fibrillin-1 (Fbn1), a key extracellular matrix glycoprotein. This condition manifests with various clinical features, the most critical of which is the formation of aortic root aneurysms. Reduced nitric oxide (NO) production due to diminished endothelial nitric oxide synthase (eNOS) activity has been linked to MFS aortic aneurysm pathology. Caveolin-1 (Cav1), a structural protein of plasma membrane caveolae, is known to inhibit eNOS activity, suggesting its involvement in MFS aneurysm progression by modulating NO levels. In this study, we examined the role of Cav1 in aortic smooth muscle and endothelial function, aortic wall elasticity, and wall strength in male and female MFS mice (FBN1+/Cys1041Gly) by generating developing Cav1-deficient MFS mice (MFS/Cav1KO). Our findings reveal that Cav1 ablation leads to a pronounced reduction in aortic smooth muscle contraction in response to phenylephrine, attributable to an increase in NO production in the aortic wall. Furthermore, we observed enhanced aortic relaxation responses to acetylcholine in MFS/Cav1KO mice, further underscoring Cav1's inhibitory impact on NO synthesis within the aorta. Notably, van Gieson staining and chamber myography analyses showed improved elastin fiber structure and wall strength in male MFS/Cav1KO mice, whereas these effects were absent in female counterparts. Cav1's regulatory influence on aortic root aneurysm development in MFS through NO-mediated modulation of smooth muscle and endothelial function, with notable sex-dependent variations.

The role of oxidative stress in aortic dissection: a potential therapeutic target

The incidence of aortic dissection (AD) is steadily increasing, driven by the rising prevalence of chronic conditions such as hypertension and the global aging of the population. Oxidative stress emerges as a pivotal pathophysiological mechanism contributing to the progression of AD. Oxidative stress triggers apoptosis in vascular smooth muscle cells, reshapes the extracellular matrix (ECM), and governs ECM degradation and remodeling, subsequently impacting aortic compliance. Furthermore, oxidative stress not only facilitates the infiltration of macrophages and mononuclear lymphocytes but also disrupts the integral structure and functionality of endothelial cells, thereby inducing endothelial cell dysfunction and furthering the degeneration of the middle layer of the aortic wall. Investigating antioxidants holds promise as a therapeutic avenue for addressing AD.

An exploration of alternative therapeutic targets for aortic disease in Marfan syndrome

Marfan syndrome is a rare connective tissue disorder that causes aortic dissection-related sudden death. Current conventional treatments, beta-blockers, and type 1 angiotensin II receptor blockers are prescribed to slow down aortic aneurysm progression and delay (prophylactic) aortic surgery. However, neither of these treatments ceases aortic growth completely. This review focuses on potential alternative therapeutic leads in the field, ranging from widely used medication with beneficial effects on the aorta to experimental inhibitors with the potential to stop aortic growth in Marfan syndrome. Clinical trials are warranted to uncover their full potential.

Quantitative analysis of choriocapillaris flow deficits and choroidal thickness in children with Marfan syndrome

PURPOSE

To evaluate the characteristics and associated factors of choroidal thickness (ChT) and choriocapillaris flow deficit percentage (CC FD%) in children with Marfan syndrome (MFS).

METHODS

This is a cross-sectional study. The ChT of the subfoveal area and other areas 0.5, 1.5, and 2.5 mm away from the fovea were assessed. The CC FD% of quadrant and circular regions with diameters of 0.5, 1.5 and 2.5 mm were assessed with 3×3 mm macular choriocapillaris images. Best-corrected visual acuity (BCVA) and cardiac function factor such as Z score were measured to analyse the associations with ChT and CC FD%.

RESULTS

51 MFS children and 50 healthy controls were enrolled in this study. Compared with the healthy controls, the ChT in the MFS group was thinner in the subfoveal area, temporal 0.5, 1.5 and 2.5 mm (all p<0.001). The CC FD% was higher in circle 0.5, 1.5 and 2.5 mm (all p<0.001). Multivariate regression analysis showed that CC FD% in the circle 2.5 mm when the Z score ≥2 was associated with BCVA (β=9.08 (95% CI 3.96 to 14.20); p=0.005) and Z score (β=4.19 (95% CI 1.28 to 12.00); p=0.012).

CONCLUSIONS

Thinner ChT and a higher CC FD% were observed in children with MFS, and an increased CC FD% in circle 2.5 mm was significantly associated with worse BCVA and cardiac function. These findings may help identify future visual impairment and early cardiac events in MFS children.

Hyperuricaemia Does Not Interfere with Aortopathy in a Murine Model of Marfan Syndrome

Redox stress is involved in the aortic aneurysm pathogenesis in Marfan syndrome (MFS). We recently reported that allopurinol, a xanthine oxidoreductase inhibitor, blocked aortopathy in a MFS mouse model acting as an antioxidant without altering uric acid (UA) plasma levels. Hyperuricaemia is ambiguously associated with cardiovascular injuries as UA, having antioxidant or pro-oxidant properties depending on the concentration and accumulation site. We aimed to evaluate whether hyperuricaemia causes harm or relief in MFS aortopathy pathogenesis. Two-month-old male wild-type (WT) and MFS mice (Fbn1^C1041G/+) were injected intraperitoneally for several weeks with potassium oxonate (PO), an inhibitor of uricase (an enzyme that catabolises UA to allantoin). Plasma UA and allantoin levels were measured via several techniques, aortic root diameter and cardiac parameters by ultrasonography, aortic wall structure by histopathology, and pNRF2 and 3-NT levels by immunofluorescence. PO induced a significant increase in UA in blood plasma both in WT and MFS mice, reaching a peak at three and four months of age but decaying at six months. Hyperuricaemic MFS mice showed no change in the characteristic aortic aneurysm progression or aortic wall disarray evidenced by large elastic laminae ruptures. There were no changes in cardiac parameters or the redox stress-induced nuclear translocation of pNRF2 in the aortic tunica media. Altogether, the results suggest that hyperuricaemia interferes neither with aortopathy nor cardiopathy in MFS mice.

Alteration of Blood Oxidative Stress Status in Patients with Thoracic Aortic Dissection: A Pilot Study

BACKGROUND

Thoracic aortic dissection (TAD) is a life-threatening condition which usually occurs on an aneurysmal aortic wall. Although increasing data have shown that inflammation and oxidative stress play an important role in the patho-physiology of dissection, systemic oxidative stress status (OSS) has not been clearly determined in patients suffering from TAD.

METHODS

A cohort of 115 patients presenting type A or B TAD were admitted to our center from 2013 to 2017. Out of this cohort, 46 patients were included in a study on dissected aorta (LIege study on DIssected Aorta: LIDIA). In 18 out of the 46 patients, systemic OSS parameters were evaluated after TAD diagnosis by determination of eight different antioxidants, four trace elements, two markers of oxidative lipid damage and two inflammatory markers.

RESULTS

The 18 TAD patients included 10 men and 8 women (median age: 62 years; interquartile range: 55-68) diagnosed with type A (N = 8) or B (N = 10) TAD. Low plasma levels of vitamin C, β-carotene, γ-tocopherol, thiol proteins, paraoxonase and selenium were observed in these 18 patients. By contrast, the concentration of copper and total hydroperoxides, copper/zinc ratio, as well as inflammatory markers, were higher than the reference intervals. No difference was observed in oxidative stress biomarker concentrations between type A and B TAD patients.

CONCLUSIONS

This pilot study, limited to 18 TAD patients, revealed a heightened systemic OSS, determined at 15.5 days (median) after the initial diagnosis, in those TAD patients without complications (malperfusion syndrome and aneurysm formation). Larger studies on biological fluids are needed to better characterize the oxidative stress and interpret its consequence in TAD disease.

Cordycepin suppresses vascular inflammation, apoptosis and oxidative stress of arterial smooth muscle cell in thoracic aortic aneurysm with VEGF inhibition

BACKGROUND

Thoracic aortic aneurysm (TAA) is a type of common and serious vascular disease, in which inflammation, apoptosis and oxidative stress are strongly involved in the progression. Cordycepin, a bioactive compound from Cordyceps militaris, exhibits anti-inflammatory and anti-oxidative activities. This study aimed to address the role and mechanism of cordycepin in TAA.

METHODS

The thoracic aortas were perivascularly administrated with calcium chloride (CaCl₂), and human aortic smooth muscle cells (HASMCs) were incubated with angiotensin II (Ang II) to simulate the TAA model in vivo and in vitro, respectively. The effect and mechanism of cordycepin in TAA were explored by hematoxylin and eosin (HE) staining, immunohistochemistry (IHC), immunofluorescence (IF), western blot, biochemical test, cell counting kit-8 (CCK-8), and terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) assays.

RESULTS

Cordycepin improved the CaCl₂-induced the aneurysmal alteration and disappearance of normal wavy elastic structures of the aorta tissues, TAA incidence and thoracic aortic diameter in rats, and Ang II-induced the cell viability of HASMCs. Cordycepin reversed the CaCl₂-induced the relative protein expression of cleaved caspase 9, cleaved caspase 3, interleukin (IL)-6, tumor necrosis factor (TNF)-α and IL-1β, and the relative levels of glutathione (GSH), malonaldehyde (MDA) and reactive oxygen species (ROS) in vivo, or Ang II-induced these changes in vitro. Mechanically, cordycepin reduced the relative protein expressions of vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2), cluster of differentiation 31 (CD31) and endothelial nitric oxide synthase (eNOS) in the Ang II-induced HASMCs. Correspondingly, overexpression of VEGF increased the levels of the indicators involved in apoptosis, inflammation and oxidative stress, which were antagonized with the cordycepin incubation in the Ang II-induced HASMCs.

CONCLUSION

Cordycepin inhibited apoptosis, inflammation and oxidative stress of TAA through the inhibition of VEGF.

Attenuation of Smooth Muscle Cell Phenotypic Switching by Angiotensin 1-7 Protects against Thoracic Aortic Aneurysm

Thoracic aortic aneurysm (TAA) involves extracellular matrix (ECM) remodeling of the aortic wall, leading to reduced biomechanical support with risk of aortic dissection and rupture. Activation of the renin-angiotensin system, and resultant angiotensin (Ang) II synthesis, is critically involved in the onset and progression of TAA. The current study investigated the effects of angiotensin (Ang) 1-7 on a murine model of TAA. Male 8-10-week-old ApoEKO mice were infused with Ang II (1.44 mg/kg/day) and treated with Ang 1-7 (0.576 mg/kg/day). ApoEKO mice developed advanced TAA in response to four weeks of Ang II infusion. Echocardiographic and histological analyses demonstrated increased aortic dilatation, excessive structural remodelling, perivascular fibrosis, and inflammation in the thoracic aorta. Ang 1-7 infusion led to attenuation of pathological phenotypic alterations associated with Ang II-induced TAA. Smooth muscle cells (SMCs) isolated from adult murine thoracic aorta exhibited excessive mitochondrial fission, oxidative stress, and hyperproliferation in response to Ang II. Treatment with Ang 1-7 resulted in inhibition of mitochondrial fragmentation, ROS generation, and hyperproliferation. Gene expression profiling used for characterization of the contractile and synthetic phenotypes of thoracic aortic SMCs revealed preservation of the contractile phenotype with Ang 1-7 treatment. In conclusion, Ang 1-7 prevented Ang II-induced vascular remodeling and the development of TAA. Enhancing Ang 1-7 actions may provide a novel therapeutic strategy to prevent or delay the progression of TAA.

Allopurinol blocks aortic aneurysm in a mouse model of Marfan syndrome via reducing aortic oxidative stress

BACKGROUND

Increasing evidence indicates that redox stress participates in MFS aortopathy, though its mechanistic contribution is little known. We reported elevated reactive oxygen species (ROS) formation and NADPH oxidase NOX4 upregulation in MFS patients and mouse aortae. Here we address the contribution of xanthine oxidoreductase (XOR), which catabolizes purines into uric acid and ROS in MFS aortopathy.

METHODS AND RESULTS

In aortic samples from MFS patients, XOR protein expression, revealed by immunohistochemistry, increased in both the tunicae intima and media of the dilated zone. In MFS mice (Fbn1^C1041G/+), aortic XOR mRNA transcripts and enzymatic activity of the oxidase form (XO) were augmented in the aorta of 3-month-old mice but not in older animals. The administration of the XOR inhibitor allopurinol (ALO) halted the progression of aortic root aneurysm in MFS mice. ALO administrated before the onset of the aneurysm prevented its subsequent development. ALO also inhibited MFS-associated endothelial dysfunction as well as elastic fiber fragmentation, nuclear translocation of pNRF2 and increased 3'-nitrotyrosine levels, and collagen maturation remodeling, all occurring in the tunica media. ALO reduced the MFS-associated large aortic production of H₂O₂, and NOX4 and MMP2 transcriptional overexpression.

CONCLUSIONS

Allopurinol interferes in aortic aneurysm progression acting as a potent antioxidant. This study strengthens the concept that redox stress is an important determinant of aortic aneurysm formation and progression in MFS and warrants the evaluation of ALO therapy in MFS patients.

The Genetics and Typical Traits of Thoracic Aortic Aneurysm and Dissection

Genetic predisposition and risk factors such as hypertension and smoking can instigate the development of thoracic aortic aneurysm (TAA), which can lead to highly lethal aortic wall dissection and/or rupture. Monogenic defects in multiple genes involved in the elastin-contractile unit and the TGFβ signaling pathway have been associated with TAA in recent years, along with several genetic modifiers and risk-conferring polymorphisms. Advances in omics technology have also provided significant insights into the processes behind aortic wall degeneration: inflammation, epigenetics, vascular smooth muscle phenotype change and depletion, reactive oxygen species generation, mitochondrial dysfunction, and angiotensin signaling dysregulation. These recent advances and findings might pave the way for a therapy that is capable of stopping and perhaps even reversing aneurysm progression.

Contribution of Oxidative Stress (OS) in Calcific Aortic Valve Disease (CAVD): From Pathophysiology to Therapeutic Targets

Calcific aortic valve disease (CAVD) is a major cause of cardiovascular mortality and morbidity, with increased prevalence and incidence. The underlying mechanisms behind CAVD are complex, and are mainly illustrated by inflammation, mechanical stress (which induces prolonged aortic valve endothelial dysfunction), increased oxidative stress (OS) (which trigger fibrosis), and calcification of valve leaflets. To date, besides aortic valve replacement, there are no specific pharmacological treatments for CAVD. In this review, we describe the mechanisms behind aortic valvular disease, the involvement of OS as a fundamental element in disease progression with predilection in AS, and its two most frequent etiologies (calcific aortic valve disease and bicuspid aortic valve); moreover, we highlight the potential of OS as a future therapeutic target.

Reactive oxygen species in cardiovascular diseases: an update

Cardiovascular diseases are among the leading causes of death worldwide, imposing major health threats. Reactive oxygen species (ROS) are one of the most important products from the process of redox reactions. In the onset and progression of cardiovascular diseases, ROS are believed to heavily influence homeostasis of lipids, proteins, DNA, mitochondria, and energy metabolism. As ROS production increases, the heart is damaged, leading to further production of ROS. The vicious cycle continues on as additional ROS are generated. For example, recent evidence indicated that connexin 43 (Cx43) deficiency and pyruvate kinase M2 (PKM2) activation led to a loss of protection in cardiomyocytes. In this context, a better understanding of the mechanisms behind ROS production is vital in determining effective treatment and management strategies for cardiovascular diseases.