High Salt Diet Triggers Aortic Dissection Through a Hidden Mitochondrial Pathway
Researchers discover that salt-triggered aortic dissection hinges on a receptor that guards mitochondrial energy metabolism in vessel walls.
Summary
Scientists have uncovered a molecular link between high-salt diets and thoracic aortic dissection, a life-threatening tear in the body's largest artery. A receptor called NPR-C, found on vascular smooth muscle cells, normally protects the aorta by maintaining mitochondrial energy metabolism. When NPR-C is absent or suppressed, a high-salt diet combined with elevated blood pressure causes the aortic wall to weaken and tear. The mechanism involves a disrupted fat-burning process inside mitochondria, driven by ERK1/2 signaling suppressing a key regulator called PPARγ. Crucially, two potential therapeutic interventions—a drug that activates NPR-C and spermidine supplementation, which restores mitochondrial function—both prevented dissection in mouse models. These findings suggest that dietary salt intake may be a modifiable trigger for this deadly condition, and that mitochondrial support may be a viable prevention strategy.
Detailed Summary
Thoracic aortic dissection (TAD) is among the most catastrophic cardiovascular emergencies, carrying extremely high mortality and having almost no effective drug treatments. Understanding what triggers the breakdown of the aortic wall is essential for developing preventive strategies. This study from Ruijin Hospital in Shanghai investigated whether the natriuretic peptide receptor C (NPR-C) plays a protective role in TAD and how high dietary salt intake fits into the picture.
Using human transcriptomic and single-cell sequencing data from acute TAD patients, the researchers found that NPR-C expression was significantly reduced in diseased aortic tissue. They then created mice with NPR-C selectively deleted in vascular smooth muscle cells (VSMCs). These mice developed TAD only when challenged with both angiotensin II and a high-salt diet simultaneously—neither condition alone was sufficient. This pinpoints high salt as a critical co-trigger that acts through this receptor pathway.
RNA sequencing of affected aortas revealed a dramatic downregulation of mitochondrial fatty acid oxidation (FAO) genes. Specifically, HADHB—a subunit of the mitochondrial trifunctional protein essential for FAO—was sharply reduced. Mechanistically, loss of NPR-C activated ERK1/2 signaling, which suppressed PPARγ activity and in turn inhibited HADHB expression, impairing mitochondrial energy metabolism. This led to extracellular matrix degradation, VSMC apoptosis, and aortic inflammation.
Therapeutically, two interventions proved effective in mouse models: C-ANP4-23, a pharmacological NPR-C agonist, slowed TAD progression, and spermidine (SPD), a naturally occurring polyamine that activates mitochondrial trifunctional protein, prevented TAD formation entirely in the knockout mice.
These findings position high salt intake as an underappreciated trigger for aortic dissection and nominate NPR-C activation and spermidine supplementation as novel preventive strategies worth investigating clinically. The study is limited by its preclinical nature, and human translation remains to be established.
Key Findings
- NPR-C deficiency in vascular smooth muscle cells, combined with high salt diet, triggers thoracic aortic dissection in mice.
- The mechanism involves ERK1/2 suppressing PPARγ, which reduces HADHB expression and impairs mitochondrial fatty acid oxidation.
- High salt diet alone is insufficient; it acts as a critical co-trigger alongside angiotensin II and NPR-C loss.
- Spermidine supplementation prevented aortic dissection by restoring mitochondrial trifunctional protein activity.
- The NPR-C agonist C-ANP4-23 mitigated TAD progression in a separate mouse model, suggesting a druggable target.
Methodology
The study integrated human TAD transcriptomic and single-cell sequencing datasets with conditional VSMC-specific and endothelial-specific NPR-C knockout mouse models. Mechanistic pathways were elucidated via RNA sequencing and pathway analysis of aortic tissue. Therapeutic interventions (C-ANP4-23 and spermidine) were tested in established murine TAD models using BAPN or angiotensin II plus high-salt diet protocols.
Study Limitations
This summary is based on the abstract only, as the full text was not accessible; details of methodology and statistical analyses could not be fully evaluated. All interventional findings are from mouse models, and direct human clinical relevance has not yet been demonstrated. The interaction between high salt, angiotensin II, and NPR-C may not fully recapitulate human TAD pathogenesis.
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