Inflammatory cells in the ascending aortic aneurysm in patients with type 2 diabetes versus patients with hypertension

Abstract

Aortic aneurysms occur relatively frequently in the ascending thoracic aorta, but are rarely seen in patients with type 2 diabetes. Our aim was to evaluate inflammatory cell infiltration in the ascending aortic aneurysm wall in patients with diabetes without arterial hypertension (DM2 group, N=6) versus hypertensive non-diabetic patients (AH group, N=34). For histologic analysis, the sections were stained with hematoxylin-eosin and Movat pentachrome. The immunohistochemical staining was used to analyze the infiltration of pro-inflammatory (CD68) and anti-inflammatory macrophages (CD163), T helper (CD4) and T killer cells (CD8), and B (CD79a) and plasma cells (CD138) in all three layers of aneurysms of both groups. The statistical significance of the differences between groups was evaluated by ANOVA and the Welch test.
 In comparison to the AH group, the DM2 group developed less severe infiltration of pro-inflammatory macrophages (P=0.004) and B cells (P=0.025) in the tunica intima, and tunica media (P=0.049, P=0.007, respectively), and fewer plasma cells in the tunica media (P=0.024) and tunica adventitia (P=0.017). We found no significant differences in the number of T helper, T killer cells, and anti-inflammatory macrophages and in the amount of collagen and elastic fibers, ground substance, and smooth muscle cells in all three layers of the vessel wall. Except in tunica adventitia of DM2 group, there were more collagen fibers overall (P=0.025). 
 Thus, we conclude that the histological structure of the aneurysm in diabetics without hypertension is almost the same as in hypertensive patients without diabetes. Diabetics had significantly less inflammatory infiltration in all three layers of the vessel wall, and more collagen fibers in tunica adventitia.

Differences between inflammatory cells infiltrated into tunica intima, media, and adventitia of ascending aortic aneurysms within diabetic and hypertensive patients

“…In our current and recently published study [17], we observed M1 and M2 macrophages and Th, Tk, B, and plasma cells in all three wall layers in ascending thoracic aorta aneurysms in hypertensive and diabetic patients.…”

“…The patients had either DM (group DM; N ═ 8) or AH (group AH; N ═ 37). The exclusion criteria were DM and AH, DM type 1, and genetic mutations [ 17 ].…”

“…Among the inflammatory cells infiltrated in the aneurismal wall, in the abdominal and also thoracic part, T cells were found to be the most numerous, followed by macrophages, B cells, and plasma cells [8,9,[14][15][16][17]. It was reported that the majority of the T cells population are T helper cells (Th) [8,17,18] which are involved in macrophage activation, direct destruction of the aortic wall, and promotion of vascular smooth muscle cells (VSMCs) apoptosis [8,19]. Killer T cells (Tk) are rare in the aneurysm wall [17].…”

“…It was reported that the majority of the T cells population are T helper cells (Th) [ 8 , 17 , 18 ] which are involved in macrophage activation, direct destruction of the aortic wall, and promotion of vascular smooth muscle cells (VSMCs) apoptosis [ 8 , 19 ]. Killer T cells (Tk) are rare in the aneurysm wall [ 17 ]. They also contribute to the development of aneurysms by promoting matrix metalloprotease activity and cellular apoptosis [ 18 , 20 ].…”

“…Recently, our research group reported that the wall of an aortic aneurysm in diabetic patients was less infiltrated with B and plasma cells and M1 macrophages compared to inflammatory infiltration in aneurysm of hypertensives. The minor infiltration of B and M1 cells was found in the tunica intima, tunica media, and plasma cells were found in the tunica media and tunica adventitia [ 17 ].…”