Hyperuricemia exacerbates abdominal aortic aneurysm formation through the URAT1/ERK/MMP-9 signaling pathway

Diagnostic value of uric acid to high-density lipoprotein cholesterol ratio in abdominal aortic aneurysms

BACKGROUND

Abdominal aortic aneurysm (AAA) is highly lethal upon onset of acute aortic diseases (AAD) or rupture. Dyslipidaemia and hyperuricaemia are important risk factors for the development of AAA and AAD as well as aortic disease-related death. The aim of this study was to explore whether uric acid (UA) to high-density lipoprotein cholesterol (HDL-C) ratio (UHR) can be used as an independent predictor of the presence of AAA or AAD.

METHODS

Three hundred subjects, including 100 AAA patients (AAA group), 100 AAD patients (AAD group) and 100 controls (CON group), were recruited in this study. UHR and other serum samples were obtained upon the patients' admission before any medical treatment. The optimal cut-off points of UHR were determined using receiver operating characteristic (ROC) curve analysis.

RESULTS

The UHR in AAA group was significantly higher than that in CON group, but there was no significant difference between AAD group and CON group. The optimal cut-off point of UHR for AAA was 7.78 (sensitivity 84.7%, specificity 62.4%, and AUC 0.811; p < 0.001), and UHR (OR: 1.122, 95%CI: 1.064-1.184; p < 0.001) was found to be an independent factor for predicting AAA after adjusting for traditional AAA risk factor.

CONCLUSION

UHR can be widely used in clinical practice as an auxiliary tool for screening AAA. The optimal cut-off point for UHR to AAA was determined for the first time in Chinese subjects.

Effect of serum uric acid on the risk of aortic aneurysm and dissection: A mendelian randomization analysis

Aortic aneurysm and dissection (AAD) are severe vascular diseases with high mortality rates. However, the causal relationship between serum uric acid levels and the occurrence of AAD remains a subject of controversy. To address this issue, we conducted a two-sample Mendelian randomization (MR) analysis to investigate whether there is a causal association between these factors. We obtained single-nucleotide polymorphisms (SNPs) data related to serum uric acid levels from the FinnGen study and data on AAD from the UK Biobank. Various two-sample MR methods, including inverse variance weighted (IVW) analysis, MR-Egger regression analysis, weighted median analysis, and contamination mixture method, were employed to assess the causal relationship between serum uric acid and the risk of AAD. Sensitivity analysis was conducted to evaluate the stability and reliability of the results. The findings revealed a positive association between serum uric acid levels and the risk of aortic aneurysm (AA) (odds ratio [OR] = 1.200, 95 % confidence interval [CI]: 1.020-1.400, P = 0.0239). However, no significant correlation was observed between serum uric acid levels and the occurrence of aortic dissection (AD) (OR = 0.893, 95 % CI = 0.602-1.326, P = 0.576). Our study, which employed MR analysis, identified a positive association between serum uric acid levels and the risk of AA. However, we did not observe a significant correlation with AD.

Association of serum uric acid level with intracranial aneurysms: A Mendelian randomization study

Objective

Numerous studies have posited the involvement of serum uric acid (SUA) in the pathogenesis and progression of various cardiovascular diseases, particularly aortic aneurysms. However, the casual effect of SUA level on intracranial aneurysms (IAs) was rarely studied. Consequently, we aimed to explore the causal association between SUA and IAs using Mendelian randomization (MR) analysis.

Methods

We conducted a two-sample MR analysis with SUA as the exposure variable and IAs as the outcome variable. Genome-wide association study (GWAS) datasets for SUA were acquired from the Open GWAS catalog, including 389,404 European and 129,405 East Asian individuals. The dataset for IAs was sourced from a meta-analysis of GWASs comprising 317,636 individuals across different ancestral populations (European: 7495 cases and 71,934 controls; East Asian: 3259 cases and 234,948 controls). The MR analyses were performed according to populations (European and East Asian) and IAs status [unruptured IAs (uIAs) or aneurysmal subarachnoid hemorrhage (aSAH)], respectively. The inverse variance weighted (IVW) method was employed as primary analysis to discern causal estimates.

Results

Our findings revealed that an elevated genetically predicted SUA level (mg/dL) correlated with an increased risk of IAs among the European population (OR = 1.29 [95%CI:1.05-1.57], P = 0.013) and East Asian population (OR = 1.56 [95%CI: 1.27-1.92], P < 0.001). Among European individuals, subgroup analysis indicated a persistent causal association of SUA with uIAs (OR = 1.50 [95%CI: 1.08-2.08], P = 0.015) and aSAH (OR = 1.26 [95%CI: 1.00-1.60], P = 0.049). However, subgroup analysis in East Asian populations was not conducted due to the lack of separate data on uIAs and aSAH.

Conclusions

Our MR analysis demonstrated a causal relationship between elevated SUA levels and an amplified risk of IAs. Further rigorous investigations are imperative to provide evidence and elucidate the underlying mechanisms.

The potential involvement of glycocalyx disruption in abdominal aortic aneurysm pathogenesis

BACKGROUND

Abdominal aortic aneurysm is a weakening and expansion of the abdominal aorta. Currently, there is no drug treatment to limit abdominal aortic aneurysm growth. The glycocalyx is the outermost layer of the cell surface, mainly composed of glycosaminoglycans and proteoglycans.

OBJECTIVE

The aim of this review was to identify a potential relationship between glycocalyx disruption and abdominal aortic aneurysm pathogenesis.

METHODS

A narrative review of relevant published research was conducted.

RESULTS

Glycocalyx disruption has been reported to enhance vascular permeability, impair immune responses, dysregulate endothelial function, promote extracellular matrix remodeling and modulate mechanotransduction. All these effects are implicated in abdominal aortic aneurysm pathogenesis. Glycocalyx disruption promotes inflammation through exposure of adhesion molecules and release of proinflammatory mediators. Glycocalyx disruption affects how the endothelium responds to shear stress by reducing nitric oxide availabilty and adversely affecting the storage and release of several antioxidants, growth factors, and antithromotic proteins. These changes exacerbate oxidative stress, stimulate vascular smooth muscle cell dysfunction, and promote thrombosis, all effects implicated in abdominal aortic aneurysm pathogenesis. Deficiency of key component of the glycocalyx, such as syndecan-4, were reported to promote aneurysm formation and rupture in the angiotensin-II and calcium chloride induced mouse models of abdominal aortic aneurysm.

CONCLUSION

This review provides a summary of past research which suggests that glycocalyx disruption may play a role in abdominal aortic aneurysm pathogenesis. Further research is needed to establish a causal link between glycocalyx disruption and abdominal aortic aneurysm development.

Causal association between uric acid levels and the risk of aortic aneurysm and aortic dissection: A two-sample Mendelian randomization study

BACKGROUND AND AIMS

Increasing numbers of studies have sought to uncover the relationship between serum uric acid (UA) levels and the risk of aortic aneurysm (AA) or aortic dissection (AD), but the causality of the associations has not been established yet. To assess this potential relationship, we conducted a two-sample Mendelian randomization (MR) analysis.

METHODS AND RESULTS

We performed two-sample Mendelian randomization (MR) analysis using independent genetic variants for UA levels from a published genome-wide association study (GWAS). Summary statistics for instrument-outcome associations from FinnGen database for AA and AD. Various sensitivity analyses were performed using different MR methods including random effects inverse variance weighting, fix effects inverse variance weighting, MR-Egger, weighted median/mode, and the contamination mixture method. Genetically predicted UA levels was associated with a higher AA risk (odds ratio (OR), 1.223; 95 % confidence interval (CI), 1.058-1.388; p = 0.017) in a simple size of 209,366 individuals. No association was found between uric acid levels and the risk of AD (OR,0.812; 95 % CI, 0.423-1.200; p = 0.293).

CONCLUSION

Our study suggests a significant and robust causal association between UA levels and risk of AA but did not support such a relationship between UA levels and AD risk, which might be interpreted with caution and further confirmed. These findings support a clinically relevant causal effect of serum urate levels on the risk of AA.

Association between gout and abdominal aortic aneurysm

BACKGROUND

Previous studies have shown an association between hyperuricemia and microvascular diseases, but the association between uric acid and abdominal aortic aneurysm (AAA) remains unclear. The aim of this study was to determine the relationship between gout and AAA.

METHODS

A population-based cohort study was conducted to validate the association between gout and AAA formation. The outcome in this study was the cumulative incidence of AAA in patients with or without gout during the 14-year follow-up period.

RESULTS

Our analysis included 121,236 patients with gout and 121,236 propensity score-matched controls from the National Health Insurance Research Database in Taiwan. Compared to the controls, patients who had gout exhibited a significantly increased incidence of AAA development [adjusted hazard ratio (HR) = 2.465, p < 0.001]. We also found that patients who were treated with anti-gout medications had a significantly lower risk of being diagnosed with an AAA than patients who were not treated with anti-gout medications (adjusted HR = 0.489, p < 0.001).

CONCLUSIONS

We have provided clinical evidence that gout is associated with the development of AAA.

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.