Aortic dissections. The battle starts in the front line

Cannabidiol protects against acute aortic dissection by inhibiting macrophage infiltration and PMAIP1-induced vascular smooth muscle cell apoptosis

Acute aortic dissection (AAD) progresses rapidly and is associated with high mortality; therefore, there remains an urgent need for pharmacological agents that can protect against AAD. Herein, we examined the therapeutic effects of cannabidiol (CBD) in AAD by establishing a suitable mouse model. In addition, we performed human AAD single-cell RNA sequencing and mouse AAD bulk RNA sequencing to elucidate the potential underlying mechanism of CBD. Pathological assays and in vitro studies were performed to verify the results of the bioinformatic analysis and explore the pharmacological function of CBD. In a β-aminopropionitrile (BAPN)-induced AAD mouse model, CBD reduced AAD-associated morbidity and mortality, alleviated abnormal enlargement of the ascending aorta and aortic arch, and suppressed macrophage infiltration and vascular smooth muscle cell (VSMC) apoptosis. Bioinformatic analysis revealed that the pro-apoptotic gene PMAIP1 was highly expressed in human and mouse AAD samples, and CBD could inhibit Pmaip1 expression in AAD mice. Using human aortic VSMCs (HAVSMCs) co-cultured with M1 macrophages, we revealed that CBD alleviated HAVSMCs mitochondrial-dependent apoptosis by suppressing the BAPN-induced overexpression of PMAIP1 in M1 macrophages. PMAIP1 potentially mediates HAVSMCs apoptosis by regulating Bax and Bcl2 expression. Accordingly, CBD reduced AAD-associated morbidity and mortality and mitigated the progression of AAD in a mouse model. The CBD-induced effects were potentially mediated by suppressing macrophage infiltration and PMAIP1 (primarily expressed in macrophages)-induced VSMC apoptosis. Our findings offer novel insights into M1 macrophages and HAVSMCs interaction during AAD progression, highlighting the potential of CBD as a therapeutic candidate for AAD treatment.

Analysis of ascending aortic diameter and long-term prognosis in patients with ascending aortic dissection

OBJECTIVES

This study was designed to review the ascending aortic diameter of patients undergoing surgery for AAD in China and its influence on prognosis.

METHODS

In the period between January 2018 and January 2020, 265 patients eligible for analysis of ascending aorta were included in this study. The maximum diameter of the ascending aorta was assessed using preoperative computed tomography (CT) scan for patients.

RESULTS

The mean diameter of the ascending aorta of the reference population was 48.16 ± 9.37 mm, and the percentage of subjects with an aorta <55 mm was 80.38%. In this study, we found that BMI, hypertension, and bicuspid aortic valve are the main factors affecting the widening of the ascending aorta, and the diameter of the ascending aorta in patients with AAD is negatively correlated with the patient's long-term prognosis. However, there is no significant difference in survival rates among patients with different ascending aortic diameter.

CONCLUSIONS

Ascending aortas with smaller diameter are also prone to dissection, most of which occur at a lower surgical threshold than recommended by current guidelines. Therefore, the diameter of ascending aorta cannot be used as an independent risk factor for high-risk patients with aortic dissection, but it can be used as an important indicator to evaluate the long-term prognosis of patients.