Gout and Progression of Aortic Stenosis

Identification of MMP9 as a Novel Biomarker to Mitochondrial Metabolism Disorder and Oxidative Stress in Calcific Aortic Valve Stenosis

Calcific aortic valve stenosis (CAVS) is the most common heart valve disorder among humans. To date, no effective method has been identified to prevent this disease. Herein, we aimed to identify novel diagnostic and mitochondria-related biomarkers of CAVS, based on two machine learning algorithms. We further explored their association with infiltrating immune cells and studied their potential function in CAVS. The GSE12644, GSE51472, and GSE83453 expression profiles were downloaded from the Gene Expression Omnibus (GEO) repository. The GSE12644 and GSE51472 datasets were integrated to identify differentially expressed genes (DEGs). GSE12644 contains 10 normal and 10 CAVS samples, whereas GSE51472 contains 5 normal and 10 CAVS samples. GO and KEGG assays of DEGs were conducted, and the correlation between matrix metalloproteinase 9 (MMP9) expression and immune cell infiltration was explored, using CIBERSORT. The LASSO regression model and SVM-RFE analysis were used to identify diagnostic genes. The expression of MMP9 in CAVS and non-CAVS samples was measured using RT-PCR, western blotting and immunohistochemistry. A series of functional experiments were performed to explore the potential role of MMP9 in mitochondrial metabolism and oxidative stress during CAVS progression. Twenty-two DEGs were identified, of which six genes (SCG2, PPBP, TREM1, CCL19, WIF1, and MMP9) were ultimately distinguished as diagnostic genes in CAVS. Of these, MMP9 was indicated as a mitochondria-related gene, the expression and diagnostic value of which were further confirmed in the GSE83453 dataset. Correlation analysis revealed a positive correlation between MMP9 and infiltrating immune cells. In our cohort, MMP9 expression was distinctly increased in CAVS samples, and its inhibition attenuated the calcification of valve interstitial cells (VICs) by suppressing mitochondrial damage and oxidative stress. Taken together, our findings suggest MMP9 as a novel mitochondrial dysfunction biomarker and therapeutic target for CAVS.

Higher rate of aortic stenosis progression in patients with bicuspid versus tricuspid aortic valve - A single center experience

PURPOSE

We sought to investigate aortic stenosis (AS) progression rate (pr) with the comparison between bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) morphology.

MATERIALS AND METHODS

We compared ASpr in patients with BAV and TAV examined by transthoracic echocardiography (TTE) in the years 2004-2019.

RESULTS

Data from 363 TTEs in 161 AS patients (median age 70 [61-77] years; 63% men; 25% with BAV; 20% with severe AS) performed at different time points (median time interval 10 months) was analyzed. We assessed changes of AS severity with peak velocity through aortic valve (Vmax), mean/peak pressure gradients (MG/PG), aortic valve area by planimetry and continuity equation (AVAce). We compared pr (defined as parameter change per year) between the BAV and the TAV groups. BAV patients showed faster ASpr with odds ratio 3.467 and 95% confidence intervals 1.36 to 8.86, moreover, expressed as a quicker AVAce decrease 0 (-0.4-0.0) in the BAV vs. 0 (-0.15 - 0.0) cm²/year in the TAV group, p ​= ​0.02. Furthermore, in BAV, female sex was associated with lower ASpr (p ​= ​0.01), and in the whole group a larger aortic diameter was a predictor of faster progression (p ​< ​0.001).

CONCLUSION

The ASpr, expressed as a decrease in the AVAce, was faster in BAV. Moreover, ASpr depends on both: valve morphology being faster in BAV and Vmax increase. Furthermore, the female sex was related to slower pace of AVA reduction in BAV subgroup whereas the larger baseline aortic diameter associated to faster AS progression in the whole studied group.