Abstract Body (Do not enter title and authors here): Background: Calcific aortic valve stenosis (AS) affects 3% of older adults and still lacks medical treatment. The deacetylase Sirtuin 1 (SIRT1) may influence key pathways linked to AS progression. Sodium-glucose co-transporter 2 inhibitors (SGLT2i), glucose-lowering agents, have been shown to reduce cardiovascular events (likely via SIRT1), but their benefits in AS are unknown.
Hypothesis: Our study probes SIRT1’s impact on AS and the potential of SGLT2i to curb valve fibro-calcification.
Methods: RNA-seq data of human aortic valve tissues were collected from the ARChS4 database. SIRT1 knockdown (SIRT1 KD) and overexpression (SIRT1 Over) valve interstitial cells (VIC) were generated by CRISPR/dCas9. RT-qPCR, immunofluorescence, and calcification assays were used to characterize mutant VICs. Conditioned medium experiments were implemented to evaluate SGLT2i effect on cellular cross-talk and calcification. Diabetic patients’ data from the Lombardy regional healthcare database, treated with sulphonylureas (SU; no effect on SIRT1) and SGLT2i (acting on SIRT1), were selected and matched 1:1 by age, sex, and multisource comorbidity score. Cumulative incidence of hospitalization for non-rheumatic aortic valve disease was assessed by Kaplan-Meier and multivariable Cox proportional hazards models were used to estimate hazard ratios.
Results: RNA-seq showed that SIRT1 could be a master regulator of multiple AS-related pathways. Functional studies on mutant VICs revealed that SIRT1 directly regulates antioxidant processes, extracellular-matrix remodeling, and calcification by modulating key transcription factors. Moreover, calcification assays further support this role revealing an increased calcification in SIRT1 KD VICs (+51%, p<0.01) and a concomitant decrease in VIC SIRT1 Over (-24%; p<0.01) when compared to wild type. Then, exploring SGLT2i impact on calcification, we showed that VICs cultured in SGLT2i-treated-endothelial medium exhibited reduced calcification (-35%, p<0.01) associated with endothelial-increased nitric oxide levels, while SIRT1 inhibition enhanced VIC calcification (+68%, p<0.01). Real-world data analysis revealed that the SGLT2i-treated group had a 40% lower incidence of hospitalized patients for non-rheumatic aortic valve disease compared to the SU-treated group.
Conclusions: Our findings reveal SIRT1 as a central driver of fibro-calcific remodeling in AS and uncover SGLT2i as a promising way to slow valve degeneration via SIRT1 activation.