Daily Cardiology Research Analysis
Analyzed 100 papers and selected 3 impactful papers.
Summary
Three impactful cardiology studies span basic, imaging, and genomic science: (1) Nrf1 activation in cardiomyocytes co-regulates proteasome and autophagy to protect the heart from ischemia/reperfusion injury; (2) an MRI-derived effective right ventricular ejection fraction (eRVEF) outperforms conventional RVEF for mortality risk stratification in functional tricuspid regurgitation; and (3) rare regulatory mutations rewire chromatin to disrupt mesenchymal programs in bicuspid aortic valve, revealing 198 candidate genes.
Research Themes
- Cardiac proteostasis and ischemia/reperfusion cardioprotection
- Imaging biomarkers for right-sided valvular disease risk stratification
- Regulatory genomics and chromatin architecture in congenital valve disease
Selected Articles
1. Nrf1 coordinates proteasome activity and autophagy to maintain cardiac proteostasis.
Using gain- and loss-of-function mouse models with multi-omics, the authors show that Nrf1 activation in cardiomyocytes during ischemia/reperfusion improves cardiac function by co-activating proteasome pathways and autophagy. Nrf1, but not Nrf2, is required for autophagy and baseline cardiac performance, positioning Nrf1 as a therapeutic target for ischemic heart disease.
Impact: This mechanistic study uncovers a dual role of Nrf1 in coordinating proteostasis via proteasome and autophagy, establishing a new therapeutic axis for ischemic cardioprotection.
Clinical Implications: Although preclinical, targeting Nrf1 to co-activate proteasome and autophagy could be developed as an adjunct therapy to limit ischemia/reperfusion injury and improve post-ischemic recovery.
Key Findings
- Transient cardiomyocyte Nrf1 activation during ischemia/reperfusion improves cardiac function.
- Nrf1 activates autophagy in addition to proteasome regulation; autophagy is essential for Nrf1’s cardioprotection.
- Loss-of-function demonstrates Nrf1 (not Nrf2) is required for autophagy and baseline cardiac performance.
- Multi-omics delineate transcriptional and post-transcriptional programs underpinning Nrf1’s protective effects.
Methodological Strengths
- Rigorous mechanistic design with cardiomyocyte-specific gain/loss-of-function models and in vivo ischemia/reperfusion.
- Integrated multi-omics to dissect transcriptional and post-transcriptional pathways.
Limitations
- Preclinical mouse data; human validation and translational dosing/safety are not addressed.
- Temporal control and potential off-target consequences of Nrf1 activation in clinical settings remain undefined.
Future Directions: Validate Nrf1-centric therapies in large-animal models, define optimal activation windows, and assess safety/efficacy in early-phase clinical trials for acute coronary syndromes.
Proteolytic stress frequently arises during disease and aging, particularly in long-lived, post-mitotic cells such as cardiomyocytes. To maintain proteostasis, cardiomyocytes depend on coordinated protein quality control pathways, including the ubiquitin-proteasome system and autophagy. Mechanisms that activate these pathways hold therapeutic potential for heart disease. Here, we demonstrate that transient activation of nuclear factor erythroid 2-like 1 (Nfe2l1, also known as Nrf1), a transcriptional regulator of proteasome activity, in cardiomyocytes during ischemia/reperfusion injury improves cardiac function. In addition to regulating the proteasome, we identify a critical role for Nrf1 in activating autophagy, which is essential for its cardioprotective effects. Through multi-omics analyses, we define both transcriptional and post-transcriptional functions of Nrf1 that underlie its cardioprotective activity. Loss-of-function studies in mice demonstrate that Nrf1, but not its homolog Nrf2, is required for autophagy and baseline cardiac function. Together, our findings establish a dual function of Nrf1 in promoting cardiac proteostasis by regulating both proteasomal and autophagic protein quality control pathways. Activating Nrf1 thus offers a therapeutic strategy for treating ischemic heart disease.
2. Redefining Right Ventricular Function: Incremental Prognostic Utility of Effective RVEF on CMR in Functional Tricuspid Regurgitation-A Multicenter Validation Study.
In 453 patients with functional TR and two external validation cohorts (n=316), an eRVEF threshold ≤25% independently predicted mortality beyond conventional markers, including RVEF. Adding eRVEF improved model performance, whereas adding RVEF to eRVEF did not, indicating eRVEF’s superior prognostic utility.
Impact: Introduces a physiologically grounded CMR metric (eRVEF) that enhances risk stratification in TR, addressing a known gap where conventional RVEF underperforms.
Clinical Implications: eRVEF can refine prognosis and may inform timing and selection for TR interventions, follow-up intensity, and clinical trial enrichment strategies.
Key Findings
- An eRVEF threshold ≤25% independently predicted all-cause mortality in functional TR.
- Adding eRVEF to models with conventional RVEF improved mortality prediction; adding RVEF to eRVEF did not.
- Impaired eRVEF associated with advanced biventricular remodeling, worse function, higher TR volume/fraction.
- Prognostic value of eRVEF was confirmed in two external validation cohorts.
Methodological Strengths
- Derivation and external validation across multicenter cohorts with standardized CMR.
- Comprehensive adjustment for TR risk markers and head-to-head comparison with conventional RVEF.
Limitations
- Observational design with potential residual confounding.
- Generalizability of the ≤25% threshold and relatively modest median follow-up (2.7 years) warrant further study.
Future Directions: Prospective studies to test eRVEF-guided management thresholds, integration into intervention timing algorithms, and evaluation across broader TR etiologies.
BACKGROUND: Right ventricular ejection fraction (RVEF) is a known predictor of adverse outcomes; however, its prognostic value diminishes in tricuspid regurgitation (TR). OBJECTIVES: This study aims to assess whether effective right ventricular ejection fraction (eRVEF) offers a more physiologic assessment of RV function and improves risk stratification in patients with TR. METHODS: The derivation cohort comprised 453 consecutive patients with at least moderate functional TR (regurgitant fraction ≥30% or volume ≥30 mL) on cardiac magnetic resonance (CMR). eRVEF was calculated as the ratio of forward volume to RV end-diastolic volume. The eRVEF threshold (≤25%) was derived based on all-cause mortality data. Clinical data were collected from standardized questionnaires at the time of CMR and supplemented with electronic health records; the primary outcome was all-cause mortality. External validation was performed in 2 independent cohorts, totaling 316 patients using identical inclusion criteria. RESULTS: In the derivation cohort, impaired eRVEF was associated with more advanced biventricular remodeling, worse biventricular function, and greater burden of late gadolinium enhancement (P < 0.05 for all), which was paralleled by higher TR volume and fraction (both P < 0.05). Over a median follow-up period of 2.7 years (Q1-Q3: 0.6-6.6 years), 20% of the patients died; mortality was higher in patients with impaired versus preserved eRVEF (28% vs 12%; HR: 1.72 [95% CI: 1.16-2.54]; P = 0.007). After adjusting for known TR risk markers including age, RV size, TR severity, conventional RVEF, and clinical markers of right-sided congestion, eRVEF remained independently predictive of mortality (HR: 0.49 [95% CI: 0.24-0.97]; P = 0.042). Adding eRVEF to a model inclusive of RVEF improved mortality prediction (chi-square from 30.6 to 37.0; P = 0.011) whereas adding RVEF to eRVEF did not (chi-square from 35.4 to 37.0; P = 0.199). External validation confirmed the prognostic significance of eRVEF ≤25% in both cohorts (HR: 2.66-2.86; both P < 0.05). CONCLUSIONS: eRVEF independently predicts mortality in TR and provides incremental prognostic value over conventional prognostic markers.
3. Rare regulatory mutations disrupt mesenchymal molecular programs driving endocardial cushion formation in bicuspid aortic valve.
By integrating 3D genome architecture with whole-genome sequencing in BAV and matched controls, the study demonstrates that rare regulatory variants rewire chromatin to disproportionately affect valve development genes and perturb mesenchymal transcriptomes essential for endocardial cushion formation, nominating 198 candidate genes.
Impact: This work elevates rare non-coding regulatory mutations as key contributors to BAV heritability and provides a mechanistic map for future functional studies and precision diagnostics.
Clinical Implications: While not immediately practice-changing, these findings inform genetic counseling, refine variant interpretation in BAV, and may guide future diagnostic panels and therapeutic target discovery.
Key Findings
- Chromatin rewiring driven by rare regulatory mutations affected 1.8-fold more valve development genes in BAV than controls.
- Genome-wide analyses indicate disrupted transcriptomes of mesenchymal populations essential for endocardial cushion formation.
- Identified 198 candidate BAV-associated genes, highlighting heterogeneity and interplay of coding and regulatory variants.
Methodological Strengths
- Integration of high-resolution 3D genome organization profiling with matched whole-genome sequencing.
- Case-control design with mechanistic, genome-wide analyses focused on regulatory architecture.
Limitations
- Small cohort size (8 BAV vs 8 controls) limits statistical power and generalizability.
- Functional in vivo validation of nominated regulatory elements and target genes is pending.
Future Directions: Functional perturbation of candidate regulatory elements/genes in model systems, expansion to larger cohorts, and integration with single-cell multi-omics during human valve development.
Bicuspid aortic valve, a prevalent congenital malformation, predisposes individuals to severe complications. Although the condition exhibits substantial heritability, known protein-coding and common regulatory mutations explain a minority of cases. To assess the contribution of rare regulatory variants, here we integrate high-resolution three-dimensional genome organization profiling with matched whole-genome sequencing from eight individuals with bicuspid aortic valves and eight with standard tricuspid aortic valves. In bicuspid aortic valve patients, mutation-driven chromatin rewiring affected 1.8-fold more valve development genes than in healthy individuals. Genome-wide in silico analyses show that rare regulatory mutations disrupt the transcriptomes of mesenchymal cell populations necessary for endocardial cushion formation. We identify 198 candidate genes associated with bicuspid aortic valve, revealing pronounced heterogeneity and complex interplay between coding and regulatory mutations. Collectively, our findings establish rare regulatory mutations as contributors to the heritability of bicuspid aortic valve and underscore the need to elucidate their mechanistic roles in disease pathogenesis.