In-Stent Restenosis: Burn and Rebuild?

Role of C/EBP Homologous Protein in Vascular Stenosis After Carotid Artery Injury

The study aims to explore the fluctuating expression of C/EBP Homologous Protein (CHOP) following rat carotid artery injury and its central role in vascular stenosis. Using in vivo rat carotid artery injury models and in vitro ischemia and hypoxia cell models employing human aortic endothelial cells (HAECs) and vascular smooth muscle cells (T/G HA-VSMCs), a comprehensive investigative framework was established. Histological analysis confirmed intimal hyperplasia in rat models. CHOP expression in vascular tissues was assessed using Western blot and immunohistochemical staining, and its presence in HAECs and T/G HA-VSMCs was determined through RT-PCR and Western blot. The study evaluated HAEC apoptosis, inflammatory cytokine secretion, cell proliferation, and T/G HA-VSMCs migration through Western blot, ELISA, CCK8, and Transwell migration assays. The rat carotid artery injury model revealed substantial fibrous plaque formation and vascular stenosis, resulting in an increased intimal area and plaque-to-lumen area ratio. Notably, CHOP is markedly elevated in vessels of the carotid artery injury model compared to normal vessels. Atorvastatin effectively mitigated vascular stenosis and suppresses CHOP protein expression. In HAECs, ischemia and hypoxia-induced CHOP upregulation, along with heightened TNFα, IL-6, caspase3, and caspase8 levels, while reducing cell proliferation. Atorvastatin demonstrated a dose-dependent suppression of CHOP expression in HAECs. Downregulation of CHOP or atorvastatin treatment led to reduced IL-6 and TNFα secretion, coupled with augmented cell proliferation. Similarly, ischemia and hypoxia conditions increased CHOP expression in T/G HA-VSMCs, which was concentration-dependently inhibited by atorvastatin. Furthermore, significantly increased MMP-9 and MMP-2 concentrations in the cell culture supernatant correlated with enhanced T/G HA-VSMCs migration. However, interventions targeting CHOP downregulation and atorvastatin usage curtailed MMP-9 and MMP-2 secretion and suppressed cell migration. In conclusion, CHOP plays a crucial role in endothelial injury, proliferation, and VSMCs migration during carotid artery injury, serving as a pivotal regulator in post-injury fibrous plaque formation and vascular remodeling. Statins emerge as protectors of endothelial cells, restraining VSMCs migration by modulating CHOP expression.

Dysbiosis of Gut Microbiota and Metabolite Phenylacetylglutamine in Coronary Artery Disease Patients With Stent Stenosis

Introduction

Dysbiotic gut microbiota (GM) plays a regulatory role during the pathogenesis of several cardiovascular diseases, including atherosclerosis. GM-derived metabolite phenylacetylglutamine (PAGln) enhances platelet responsiveness and thrombosis potential, thereby inducing major adverse cardiovascular events. However, the role of GM and microbial metabolite PAGln in the pathogenesis of in-stent stenosis remains unknown.

Methods

16S rRNA sequencing was performed on fecal samples in 103 coronary artery disease (CAD) patients, including 35 individuals with in-stent patency (control), 32 individuals with in-stent hyperplasia (ISH), and 36 subjects with in-stent stenosis (ISS), and the levels of plasma PAGln were evaluated by enzyme-linked immunosorbent assay.

Results

The results revealed significantly enhanced microbial diversity and disrupted composition, such as enrichment of Roseburia, Blautia, and Ruminococcus, were observed in CAD patients with in-stent stenosis. The imbalance of microbial function related to PAGln synthesis and elevated plasma GM-derived metabolite PAGln levels was detected in CAD patients with in-stent stenosis. The GM-dependent diagnostic model could identify CAD patients with in-stent stenosis.

Conclusion

The current study revealed the disordered signature, altered functions, and potential diagnostic ability of GM in CAD patients with in-stent hyperplasia and stenosis. Enhanced microbiota-derived PAGln synthesis-related functions and elevated plasma PAGln levels were associated with in-stent stenosis and hyperplasia in CAD patients. Thus, an intervention targeting gut microbes may be a promising strategy to prevent stent stenosis in patients with CAD.