Hyperhomocysteinemia may aggravate abdominal aortic aneurysm formation by up-regulating RASSF2.

Abdominal aortic aneurysm (AAA) is a fatal cardiovascular disorder with high mortality and morbidity rates. To date, no drug has shown to significantly alleviate the risk of AAA. Previous studies have indicated that hyperhomocysteinemia (HHcy) significantly increases the incidence of AAA by disrupting endothelial cell homeostasis; however, the potential molecular mechanisms require clarification. Herein, we aimed to integrate transcriptomics analysis and molecular biology experiments to explore the potential molecular targets by which HHcy may increase the incidence of AAA. We integrated two AAA data profiles (GSE57691 and GSE7084) based on previously published microarray ribonucleic acid sequencing (RNAseq) data from the GEO database. Additionally, 500 µM homocysteine-treated human aorta endothelium cells microarray dataset (GSE175748) was downloaded and processed. Subsequently, single-cell RNA-seq profiles of the aortic aneurysms (GSE155468) were downloaded, scaled, and processed for further analysis. The microarray profiles analysis demonstrated that the Ras association domain family member 2 (RASSF2) and interleukin (IL)-1ß are potentially the target genes involved in the HHcy-mediated aggravation of AAA formation. Single-cell RNAseq analysis revealed that RASSF2 might impair endothelial cell function by increasing inflammatory cell infiltration to participate in AAA formation. Finally, we conducted reverse transcription quantitative polymerase chain reaction and immunofluorescence analysis to validate the up-regulated mRNA expression of RASSF2 (p = 0.008) and IL-1ß (p = 0.002) in AAA tissue compared to control tissue. Immunofluorescence staining revealed overexpression of RASSF2 protein in AAA tissue sections compared to control tissue (p = 0.037). Co-localization of RASSF2 and the aortic endothelium cell marker, CD31, was observed in tissue sections, indicating the potential involvement of RASSF2 in aortic endothelial cells. To summarise, our preliminary study revealed that HHcy may worsen AAA formation by up-regulating the expression of RASSF2 and IL-1ß in aortic endothelium cells.

Construction of a canine model with acute type B aortic dissection using a self-made pressure-driven flow device.

A reproducible canine aortic dissection (AD) model would be useful for evaluating the performance of novel endovascular treatment devices. Therefore, we attempted to create a reproducible canine model of Stanford type B AD (TBAB) by a surgical method. Computed tomography angiography was performed 2 h after the procedure to determine if a false lumen was present, and follow-up imaging was performed 10 d after the procedure using digital subtraction angiography, intravascular ultrasound (IVUS), and color Doppler flow imaging (CDFI) to confirm stable persistence of the false lumen. The success rate of model construction was 88.8% (16/18). All surviving dogs had distal re-entries (16/16). The number of re-entries in the dogs was 1.50 ± 0.52, and the mean length of the false lumen was 175.37 ± 16.98 mm. IVUS showed the area of the false lumen at the narrowest part of the arterial lumen was 84.88 ± 1.27%. The CDFI showed that the peak systolic velocity in the false lumen (10.89 ± 0.74 cm/s) was significantly slower than that in the true lumen (25.31 ± 1.72 cm/s; P<0.001). Moreover, the direction of blood flow in the true lumen was consistent, whereas that in the false lumen was disordered. We optimized the traditional surgical method to construct a canine model of TBAD to improve the success rate of model construction, and designed a novel device to lengthen the false lumen. The proposed model has wide implications in evaluating the performance of novel endovascular treatment devices and studying the AD-related hemodynamics.