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Endovascular treatment of the femoro-popliteal artery has recently become a valuable therapeutic option for popliteal arterial aneurysms. However, its efficacy remains controversial due to the relatively high rate of complications, such as stent occlusion as result of intra-stent thrombosis. The elucidation of the interplay among vessel geometrical features, local hemodynamics, and leg bending seems crucial to understand onset and progression of popliteal intra-stent thrombosis. To this aim, patient-specific computational fluid dynamic simulations were performed in order to assess the intra-stent hemodynamics of two patients endovascularly treated for popliteal arterial aneurysm by stent-grafts and experiencing intra-stent thrombosis. Both Newtonian and non-Newtonian blood rheological models were considered. Results were presented in terms of tortuosity, luminal area exposed to low (< 0.4 Pa) and high (> 1.5 Pa) time-averaged wall shear stress (TAWSS), area exposed to high (> 0.3) oscillatory shear index (OSI), and flow helicity. Study outcomes demonstrated that leg bending induced significant hemodynamic differences (> 50% increase) in both patients for all the considered variables, except for OSI in one of the two considered patients. In both leg configurations, stent-graft overlapping induced a severe discontinuity of the lumen diameter where the proximal stented zone is characterized by low tortuosity, low velocity, low helicity, low TAWSS, and high OSI; while the distal part has higher tortuosity, velocity, helicity, TAWSS, and lower OSI. Sensitivity study on applied boundary conditions showed that the different inlet velocity profiles for a given inlet waveform affect slightly the numerical solution; conversely, the shape and magnitude of the prescribed inlet waveform is determinant. Focusing on the comparison between the Newtonian and non-Newtonian blood models, the area with low TAWSS is greater in the Newtonian model for both patients, while no significant difference occurs between the surfaces with high TAWSS. Patient-specific computational fluid dynamic simulations were performed in order to assess the intra-stent hemodynamics of two patients endovascularly treated for popliteal arterial aneurysm and experiencing intra-stent thrombosis. Both Newtonian and non-Newtonian blood rheological models were considered. In both straight and bent leg configurations, stent-graft overlapping induced a severe discontinuity of the lumen diameter where the proximal stented zone is characterized by low tortuosity, low velocity, low helicity, low time-averaged wall shear stress (TAWSS), and high oscillatory index (OSI); while the distal part has higher tortuosity, velocity, helicity, TAWSS, and lower OSI. [ABSTRACT FROM AUTHOR]

A Correction to this paper has been published: https://doi.org/10.1007/s10409-021-01066-2 [ABSTRACT FROM AUTHOR]

The size of abdominal aortic aneurysm (AAA) is a well-known risk factor, predictive for rupture. The employment of Positron Emission Tomography (PET) has recently proven to be helpful in determining which AAA are at imminent risk of rupture. We applied our macroscopic sampling and histological examination protocol to I4 AAA (2 of which PET positive), in order to determine the correlations between metabolic activation of the aneurysmal wall and histomorphological findings. Our aim is to obtain a better understanding of the pathogenesis of AAA rupture and to provide a further contribute in their diagnostic evaluation. We applied our histochemical protocol (Hematoxylin-Eosin (HE), Alcian Blue (pH-I), PAS, Masson Thrichromic and Weigert) on aortic aneurysm specimen and evaluated the proliferative index by immunohistochemistry (Ki-67/MIB-I) in order to detect any relationship between PET negative aortic specimen showed follicular lymphocytic aggregatesm especially located within the advated proliferative index (Ki-67) of the flogistic aggregates in our two groups (PET positive and PET negative). We believe that further IHC investigations with enzymes that are well-known implied in AAA pathogenesis (i.e. MMP-8 and MMP-9) should provide more accurate information in predicting the risk of rupture. [ABSTRACT FROM AUTHOR]

Myostatin (Mstn) is a skeletal muscle growth inhibitor involved in metabolic disorders and heart fibrosis. In this study we sought to verify whether Mstn is also operative in atherosclerosis of abdominal aorta. In human specimens, Mstn expression was almost absent in normal vessels, became detectable in the media of non-progressive lesions and increased with the severity of the damage. In progressive atherosclerotic lesions, Mstn was present in the media, neointima, plaque shoulder and in infiltrating macrophages. Mstn co-localized with α-smooth muscle actin (α-SMA) staining and with some CD45+ cells, indicating Mstn expression in VSMCs and bloodstream-derived leukocytes. In vitro, Mstn was tested in VSMCs and monocytes. In A7r5 VSMCs, Mstn downregulated proliferation and Smoothelin mRNA, induced cytoskeletal rearrangement, increased migratory rate and MCP-1/CCR2 expression. In monocytes (THP-1 cells and human monocytes), Mstn acted as a chemoattractant and increased the MCP-1-dependent chemotaxis, F-actin, α-SMA, MCP-1 and CCR2 expression; in turn, MCP-1 increased Mstn mRNA. Mstn induced JNK phosphorylation both in VSMCs and monocytes. Our results indicate that Mstn is overexpressed in abdominal aortic wall deterioration, affects VSMCs and monocyte biology and sustains a chronic inflammatory milieu. These findings propose to consider Mstn as a new playmaker in atherosclerosis progression. [ABSTRACT FROM AUTHOR]

Resveratrol (Rsv) is a natural antioxidant polyphenol with vasoprotective properties. We evaluated whether Rsv affects the inflammatory response in an experimental model of elastase-induced abdominal aortic aneurysm. Thirty male rats were subjected to aneurysm induction and treated or not with Rsv. Circulating levels of CD62L- monocyte subset, monocyte CD 143 surface expression, MMP-9 plasma activity and TNFOL serum levels were lower in Rsv-treated rats. In conclusion, Rsv acts as an anti-inflammatory compound and could be of great relevance to improve the immune response in AAA patients. [ABSTRACT FROM AUTHOR]