T lymphocytes and aortic aneurysms

The role of transcription factors in the pathogenesis and therapeutic targeting of vascular diseases

Transcription factors (TFs) constitute an essential component of epigenetic regulation. They contribute to the progression of vascular diseases by regulating epigenetic gene expression in several vascular diseases. Recently, numerous regulatory mechanisms related to vascular pathology, ranging from general TFs that are continuously activated to histiocyte-specific TFs that are activated under specific circumstances, have been studied. TFs participate in the progression of vascular-related diseases by epigenetically regulating vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs). The Krüppel-like family (KLF) TF family is widely recognized as the foremost regulator of vascular diseases. KLF11 prevents aneurysm progression by inhibiting the apoptosis of VSMCs and enhancing their contractile function. The presence of KLF4, another crucial member, suppresses the progression of atherosclerosis (AS) and pulmonary hypertension by attenuating the formation of VSMCs-derived foam cells, ameliorating endothelial dysfunction, and inducing vasodilatory effects. However, the mechanism underlying the regulation of the progression of vascular-related diseases by TFs has remained elusive. The present study categorized the TFs involved in vascular diseases and their regulatory mechanisms to shed light on the potential pathogenesis of vascular diseases, and provide novel insights into their diagnosis and treatment.

Deep Phenotyping of T-Cells Derived From the Aneurysm Wall in a Pediatric Case of Subarachnoid Hemorrhage

Intracranial aneurysms (IAs) are very rare in children, and the characteristics of the T-cells in the IA wall are largely unknown. A comatose 7-years-old child was admitted to our center because of a subarachnoid hemorrhage due to a ruptured giant aneurysm of the right middle cerebral artery. Two days after the aneurysm clipping the patient was fully awake with left hemiparesis. T-cells from the IA wall and from peripheral blood of this patient were analyzed by multi-dimensional flow cytometry. Unbiased analysis, based on the use of FlowSOM clustering and dimensionality reduction technique UMAP, indicated that there was virtually no overlap between circulating and tissue-infiltrating T-cells. Thus, naïve T-cells and canonical memory T-cells were largely restricted to peripheral blood, while CD4^-CD8^-T-cells were strongly enriched in the IA wall. The unique CD4⁺, CD8⁺ and CD4^-CD8^-T-cell clusters from the IA wall expressed high levels of CCR5, Granzyme B and CD69, displaying thus characteristics of cytotoxic and tissue-resident effector cells. Low Ki67 expression indicated that they were nevertheless in a resting state. Among regulatory T-cell subsets, Eomes⁺Tr1-like cells were strongly enriched in the IA wall. Finally, analysis of cytokine producing capacities unveiled that the IA wall contained poly-functional T-cells, which expressed predominantly IFN-γ, TNF and IL-2. CD4⁺T-cells co-expressed also CD40L, and produced some IL-17, GM-CSF and IL-10. This report provides to our knowledge the first detailed characterization of the human T-cell compartment in the IA wall.

Integrating Bulk Transcriptome and Single-Cell RNA Sequencing Data Reveals the Landscape of the Immune Microenvironment in Thoracic Aortic Aneurysms

Thoracic aortic aneurysm (TAA) is a life-threatening cardiovascular disease whose formation is reported to be associated with massive vascular inflammatory responses. To elucidate the roles of immune cell infiltration in the pathogenesis underlying TAA, we utilized multiple TAA datasets (microarray data and scRNA-seq data) and various immune-related algorithms (ssGSEA, CIBERSORT, and Seurat) to reveal the landscapes of the immune microenvironment in TAA. The results exhibited a significant increase in the infiltration of macrophages and T cells, which were mainly responsible for TAA formation among the immune cells. To further reveal the roles of immunocytes in TAA, we inferred the intercellular communications among the identified cells of aortic tissues. Notably, we found that in both normal aortic tissue and TAA tissue, the cells that interact most frequently are macrophages, endothelial cells (ECs), fibroblasts, and vascular smooth muscle cells (VSMCs). Among the cells, macrophages were the most prominent signal senders and receivers in TAA and normal aortic tissue. These findings suggest that macrophages play an important role in both the physiological and pathological conditions of the aorta. The present study provides a comprehensive evaluation of the immune cell composition and reveals the intercellular communication among aortic cells in human TAA tissues. These findings improve our understanding of TAA formation and progression and facilitate the development of effective medications to treat these conditions.

Association of Platelet to Lymphocyte Ratio and Risk of 30-Day Postoperative Complications in Patients Undergoing Abdominal Aortic Surgical Repair

Introduction:

The predictive value of the platelet to lymphocyte ratio (PLR) has been demonstrated in several cardiovascular diseases. The aim of this study was to investigate the interest of the preoperative PLR as a predictor of 30-day postoperative outcome in patients with abdominal aortic aneurysm (AAA) undergoing open or endovascular surgical repair.

Material and Methods:

Two hundred twenty-four consecutive patients with infrarenal AAA were retrospectively included and divided into 4 quartiles according to the value of the preoperative PLR: PLR < 91.5 (group I), 91.5 < PLR < 120.8 (group II), 120.8 < PLR < 163.3 (group III), and PLR > 163.3 (group IV).

Results:

The AAA diameter was similar among the groups (54.9 mm vs 58.6, 57.5, and 58.7 mm; P = .4655). The proportion of symptomatic AAA and the procedural characteristics did not differ. Patients from group I and IV had significantly higher rates of all-cause postoperative complications compared to group II and III (55.4% and 64.3% vs 39.3% and 46.4%, respectively; P = .0478). The all-cause mortality tended to be higher in group I and IV (7.1% and 8.9% vs 0% and 3.6%, respectively; P = .1305).

Conclusion:

Extreme values of PLR are associated with a higher risk of complications following AAA surgical repair, suggesting its interest as a biomarker to evaluate the surgical risk.

High Neutrophil to Lymphocyte Ratio Is Associated With Symptomatic and Ruptured Thoracic Aortic Aneurysm

The predictive value of the neutrophil to lymphocyte ratio (NLR) has been demonstrated in several cardiovascular diseases. The aim of our study was to investigate the association between the preoperative NLR and aneurysm characteristics as well as 30-day postoperative morbidity and mortality in patients with thoracic aortic aneurysm (TAA) undergoing aortic surgical repair. Consecutive patients (n = 75) with TAA were retrospectively included over a 10-year period. Clinical characteristics, aneurysm characteristics, and 30-day postoperative outcome were recorded. The median age of patients was 71 (67-80) years. The median preoperative NLR was 3.5 (2.3-5.8). The proportion of asymptomatic TAA was significantly lower in patients with an NLR > 3.5 compared with those with an NLR < 3.5 (52.6% vs 75.7%; P = .054). The proportion of patients with pain or with ruptured TAA was significantly higher in patients with an NLR > 3.5 compared with those with NLR < 3.5 (42.1% vs 16.2%; P = .022 and 26.3% vs 2.7%; P = .007, respectively). No significant difference was observed regarding the 30-day overall postoperative mortality and morbidity. The preoperative NLR did not correlate with TAA diameter. A high preoperative NLR is significantly associated with symptomatic and ruptured TAA, suggesting a potential interest as a marker and/or player in the disease.