Acute Coronary Syndromes and the Nontarget Lesion

Impact of risk factors on intervened and non-intervened coronary lesions

INTRODUCTION

In-stent restenosis (ISR) and aggravated non-intervened coronary lesions (ANL) are two pivotal aspects of disease progression in patients with coronary artery disease (CAD). Established risk factors for both include hyperlipidemia, hypertension, diabetes, chronic kidney disease, and smoking. However, there is limited research on the comparative risk factors for the progression of these two aspects of progression. The aim of this study was to analyze and compare the different impacts of identical risk factors on ISR and ANL.

METHODS

This study enrolled a total of 510 patients with multiple coronary artery lesions who underwent repeated coronary angiography (CAG). All patients had previously undergone percutaneous coronary intervention (PCI) and presented non-intervened coronary lesions in addition to the previously intervened vessels.

RESULTS

After data analysis, it was determined that HbA1c (OR 1.229, 95% CI 1.022-1.477, P=0.028) and UA (OR 1.003, 95% CI 1.000-1.005, P=0.024) were identified as independent risk factors for ISR. Furthermore, HbA1c (OR 1.215, 95% CI 1.010-1.460, P=0.039), Scr (OR 1.007, 95% CI 1.003-1.017, P=0.009), and ApoB (OR 1.017, 95% CI 1.006-1.029, P=0.004) were identified as independent risk factors for ANL. The distribution of multiple blood lipid levels differed between the ANL only group and the ISR only group. Non-HDL-C (2.17 mmol/L vs. 2.44 mmol/L, P=0.007) and ApoB (63.5 mg/dL vs. 71.0 mg/dL, P=0.011) exhibited significantly higher values in the ANL only group compared to the ISR only group.

CONCLUSIONS

Blood glucose levels and chronic kidney disease were identified as independent risk factors for both ISR and ANL, while elevated lipid levels were only significantly associated with ANL. In patients with non-intervened coronary lesions following PCI, it is crucial to assess the concentration of non-HDL-C and ApoB as they serve as significant risk factors.

TBC1D15/RAB7-regulated mitochondria-lysosome interaction confers cardioprotection against acute myocardial infarction-induced cardiac injury

Rationale: Ischemic heart disease remains a primary threat to human health, while its precise etiopathogenesis is still unclear. TBC domain family member 15 (TBC1D15) is a RAB7 GTPase-activating protein participating in the regulation of mitochondrial dynamics. This study was designed to explore the role of TBC1D15 in acute myocardial infarction (MI)-induced cardiac injury and the possible mechanism(s) involved.

Methods: Mitochondria-lysosome interaction was evaluated using transmission electron microscopy and live cell time-lapse imaging. Mitophagy flux was measured by fluorescence and western blotting. Adult mice were transfected with adenoviral TBC1D15 through intra-myocardium injection prior to a 3-day MI procedure. Cardiac morphology and function were evaluated at the levels of whole-heart, cardiomyocytes, intracellular organelles and cell signaling transduction.

Results: Our results revealed downregulated level of TBC1D15, reduced systolic function, overt infarct area and myocardial interstitial fibrosis, elevated cardiomyocyte apoptosis and mitochondrial damage 3 days after MI. Overexpression of TBC1D15 restored cardiac systolic function, alleviated infarct area and myocardial interstitial fibrosis, reduced cardiomyocyte apoptosis and mitochondrial damage although TBC1D15 itself did not exert any myocardial effect in the absence of MI. Further examination revealed that 3-day MI-induced accumulation of damaged mitochondria was associated with blockade of mitochondrial clearance because of enlarged defective lysosomes and subsequent interrupted mitophagy flux, which were attenuated by TBC1D15 overexpression. Mechanistic studies showed that 3-day MI provoked abnormal mitochondria-lysosome contacts, leading to lysosomal enlargement and subsequently disabled lysosomal clearance of damaged mitochondria. TBC1D15 loosened the abnormal mitochondria-lysosome contacts through both the Fis1 binding and the RAB7 GAPase-activating domain of TBC1D15, as TBC1D15-dependent beneficial responses were reversed by interference with either of these two domains both in vitro and in vivo.

Conclusions: Our findings indicated a pivotal role of TBC1D15 in acute MI-induced cardiac anomalies through Fis1/RAB7 regulated mitochondria-lysosome contacts and subsequent lysosome-dependent mitophagy flux activation, which may provide a new target in the clinical treatment of acute MI.