Characterization and Significance of Monocytes in Acute Stanford Type B Aortic Dissection

Abstract

Acute aortic dissection (AAD) is one of the most common fatal diseases noted in vascular surgery. Human monocytes circulate in dynamic equilibrium and display a considerable heterogeneity. However, the role of monocytes in AAD remains elusive. In our recent study, we firstly obtained blood samples from 22 patients with Stanford type B AAD and 44 age-, sex-, and comorbidity-matched control subjects. And the monocyte proportions were evaluated by flow cytometry. Results showed that the percentage of total CD14+ monocytes in the blood samples of Stanford AAD patients was increased significantly compared with that of normal volunteers (P<0.0005), and the absolute numbers of CD14brightCD16+ and CD14brightCD16- monocytes both increased significantly regardless of the percentage of PBMC or CD14+ cells, while CD14dimCD16+ monocytes displayed the opposite tendency. However, the percentage of CD14+ cells and its three subsets demonstrated no correlation with D-dimer (DD) and C-reactive protein (CRP). Then, blood mononuclear cell (PBMC) samples were collected by Ficoll density gradient centrifugation, followed with CD14+ magnetic bead sorting. After the purity of CD14+ cells was validated over 90%, AAD-related genes were concentrated in CD14+ monocytes. There were no significant differences observed with regard to the mRNA expression levels of MMP1 (P=0.0946), MMP2 (P=0.3941), MMP9 (P=0.2919), IL-6 (P=0.4223), and IL-10 (P=0.3375) of the CD14+ monocytes in Stanford type B AAD patients compared with those of normal volunteers. The expression levels of IL-17 (P<0.05) was higher in Stanford type B AAD patients, while the expression levels of TIMP1(P<0.05), TIMP2(P<0.01), TGF-β1 (P<0.01), SMAD3 (P<0.01), ACTA2 (P<0.001), and ADAMTS-1 (P<0.001) decreased. The data suggested that monocytes might play an important role in the development of Stanford type B AAD. Understanding of the production, differentiation, and function of monocyte subsets might dictate future therapeutic avenues for Stanford type B AAD treatment and can aid the identification of novel biomarkers or potential therapeutic targets for decreasing inflammation in AAD.

Association Between Preoperative Monocyte to High-Density Lipoprotein Ratio on In-hospital and Long-Term Mortality in Patients Undergoing Endovascular Repair for Acute Type B Aortic Dissection

“…Du et al also reported similar findings, compared with healthy controls, in a Chinese Han population (19). Another study on acute TBAD patients found that the percentage of CD14 + monocytes was significantly higher than that of normal volunteers, in which the percentages of the two monocyte subsets (CD14 bright CD16 − and CD14 bright CD16 + ) were increased significantly (P < 0.001) (16). Furthermore, selective depletion of monocyte/macrophage in mice model dramatically reduced the incidence of aortic dissection, supporting that monocytes/ macrophages have an important role in the pathophysiology of aortic dissection (27).…”

“…Recruitment and activation of multiple inflammatory cells could lead to apoptosis of vascular smooth muscle cells, thus inducing wall fragility and subsequent aortic dilation, dissection, and even rupture (1,25). In this condition, the numbers and phenotypes of monocytes were significantly altered (16,26). A previous study demonstrated that classical monocytes were significantly increased in patients among the acute aortic dissection group compared with patients with carotid artery stenosis or subjects with traditional cardiovascular risk factors (26).…”

“…In recent years, elevated MHR has been revealed as a novel indicator for cardiovascular diseases and correlated with poor outcomes (8)(9)(10)(11). For patients with acute aortic dissection, several studies have illustrated that medial recruitment and activation of monocytes/ macrophages and subsequent elastin degradation are initial events in the early stages (12)(13)(14)(15), leading to a significant change in the numbers and phenotypes of monocytes (16). HDL-C was found to be inversely correlated with the monocyte counts in mice as well as children with familial hypercholesterolemia (17), and a lower HDL-C may increase the risk of aortic dissection (18).…”

Comprehensive Analysis of Key m6A Modification Related Genes and Immune Infiltrates in Human Aortic Dissection

“…In this regard, monocytes and macrophages may work together in a certain relationship to promote AD. Furthermore, the data obtained by Lu et al suggested that monocytes might play an important role in type B AAD (BAAD) ( 56 ). In terms of mortality, the lower lymphocyte-to-monocyte ratio may be independently associated with the mortality of type A AAD (AAAD) ( 57 ).…”

Isolation of bacteria from artificial bronchoalveolar lavage fluid using density gradient centrifugation and their accessibility by Raman spectroscopy

“…During centrifugation, the sample is centrifuged through the gradient, and the individual particles remain at the gradient density level that matches their own density. Frequently used solutions are Percoll [ 29 ], Ficoll [ 30 ], sucrose [ 31 ] and OptiPrep [ 32 ], the last of which was used in this study. Therefore, two different solutions were used and mixed together.…”