Upon inflammation, monocyte-derived macrophages (MΦ) infiltrate blood vessels to regulate several processes involved in vascular pathophysiology. However, little is known about the mediators involved. Macrophage polarization is crucial for a fast and efficient initial response (GM-MΦ) and a good resolution (M-MΦ) of the inflammatory process. The functional activity of polarized MΦ is exerted mainly through their secretome, which can target other cell types, including endothelial cells. Endoglin (CD105) is a cell surface receptor expressed by endothelial cells and MΦ that is markedly upregulated in inflammation and critically involved in angiogenesis. In addition, a soluble form of endoglin with anti-angiogenic activity has been described in inflammation-associated pathologies. The aim of this work was to identify components of the MΦ secretome involved in the shedding of soluble endoglin. We find that the GM-MΦ secretome contains metalloprotease 12 (MMP-12), a GM-MΦ specific marker that may account for the anti-angiogenic activity of the GM-MΦ secretome. Cell surface endoglin is present in both GM-MΦ and M-MΦ, but soluble endoglin is only detected in GM-MΦ culture supernatants. Moreover, MMP-12 is responsible for the shedding of soluble endoglin in vitro and in vivo by targeting membrane-bound endoglin in both MΦ and endothelial cells. These data demonstrate a direct correlation between GM-MΦ polarization, MMP-12, and soluble endoglin expression and function. By targeting endothelial cells, MMP-12 may represent a novel mediator involved in vascular homeostasis.

The results indicate that long-term hypercholesterolemia combined with high levels of sEng leads to the aggravation of endothelial and vessel wall dysfunction in aorta, with possible alterations of the membrane endoglin/eNOS signaling, suggesting that high levels of soluble endoglin might be considered as a risk factor of cardiovascular diseases.

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Our objective was to investigate the effect of cholesterol [hypercholesterolemia and 7‐ketocholesterol (7K)] on endoglin (Eng) expression and regulation with respect to endothelial or vascular dysfunction in vivo and in vitro. In vivo experiments were performed in 2‐mo‐old atherosclerosis‐prone apolipoprotein E–deficient/LDL receptor–deficient (ApoE−/−/LDLR−/−) female mice and their wild‐type C57BL/6J littermates. In in vitro experiments, human aortic endothelial cells (HAECs) were treated with 7K. ApoE−/−/LDLR−/− mice developed hypercholesterolemia accompanied by increased circulating levels of P‐selectin and Eng and a disruption of NO metabolism. Functional analysis of the aorta demonstrated impaired vascular reactivity, and Western blot analysis revealed down‐regulation of membrane Eng/Smad2/3/eNOS signaling in ApoE−/−/LDLR−/− mice. 7K increased Eng expression via Krüppel‐like factor 6 (KLF6), liver X nuclear receptor, and NF‐&x03BA;B in HAECs. 7K‐induced Eng expression was prevented by the treatment with 2‐hydroxypropyl‐β‐cyclodextrin; 8‐{[5‐chloro‐2‐(4‐methylpiperazin‐1‐yl) pyridine‐4‐carbonyl] amino}‐1‐(4‐fluorophenyl)‐4, 5‐dihydrobenzo[g]indazole‐3‐carboxamide; or by KLF6 silencing. 7K induced increased adhesion and transmigration of monocytic human leukemia promonocytic cell line cells and was prevented by Eng silencing. We concluded that hypercholesterolemia altered Eng expression and signaling, followed by endothelial or vascular dysfunction before formation of atherosclerotic lesions in ApoE−/−/LDLR−/− mice. By contrast, 7K increased Eng expression and induced inflammation in HAECs, which was followed by an increased adhesion and transmigration of monocytes via endothelium, which was prevented by Eng inhibition. Thus, we propose a relevant role for Eng in endothelial or vascular dysfunction or inflammation when exposed to cholesterol.—Vicen, M., Vitverova, B., Havelek, R., Blazickova, K., Machacek, M., Rathouska, J., Najmanová, I., Dolezelova, E., Prasnicka, A., Sternak, M., Bernabeu, C, Nachtigal, P. Regulation and role of endoglin in cholesterol‐induced endothelial and vascular dysfunction in vivo and in vitro. FASEB J. 33, 6099–6114 (2019). http://www.fasebj.org

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Soluble endoglin (sEng) released into the circulation was suggested to be related to cardiovascular based pathologies. It was demonstrated that a combination of high sEng levels and long-term exposure (six months) to high fat diet (HFD) resulted in aggravation of endothelial dysfunction in the aorta. Thus, in this study, we hypothesized that a similar experimental design would affect the heart morphology, TGFβ signaling, inflammation, fibrosis, oxidative stress and eNOS signaling in myocardium in transgenic mice overexpressing human sEng. Three-month-old female transgenic mice overexpressing human sEng in plasma (Sol-Eng + high) and their age-matched littermates with low levels of human sEng (Sol-Eng + low) were fed a high-fat diet containing 1.25% of cholesterol and 40% of fat for six months. A blood analysis was performed, and the heart samples were analyzed by qRT-PCR and Western blot. The results of this study showed no effects of sEng and HFD on myocardial morphology/hypertrophy/fibrosis. However, the expression of pSmad2/3 and p-eNOS was reduced in Sol-Eng + high mice. On the other hand, sEng and HFD did not significantly affect the expression of selected members of TGFβ signaling (membrane endoglin, TGFβRII, ALK-5, ALK-1, Id-1, PAI-1), inflammation (VCAM-1, ICAM-1), oxidative stress (NQO1, HO-1) and heart remodeling (PDGFβ, COL1A1, β-MHC). In conclusion, the results of this study confirmed that sEng, even combined with a high-fat diet inducing hypercholesterolemia administered for six months, does not affect the structure of the heart with respect to hypertrophy, fibrosis, inflammation and oxidative stress. Interestingly, pSmad2/3/p-eNOS signaling was reduced in both the heart in this study and the aorta in the previous study, suggesting a possible alteration of NO metabolism caused by six months exposure to high sEng levels and HFD. Thus, we might conclude that sEng combined with a high-fat diet might be related to the alteration of NO production due to altered pSmad2/3/p-eNOS signaling in the heart and aorta.

Background Lipoprotein apheresis (LA) is considered as an add-on therapy for patients with familial hypercholesterolemia (FH). We aimed to analyze the data collected in the last 15 years from FH patients treated with LA, to elucidate the benefit of this procedure with respect to plasma lipids, biomarkers of inflammation, and endothelial dysfunction and soluble endoglin. Results 14 patients (10 heterozygous FH patients (HeFH), 4 homozygous FH patients (HoFH)) were treated by long-term lipoprotein apheresis. Lipid levels were examined, and ELISA detected biomarkers of inflammation and soluble endoglin. Paired tests were used for intergroup comparisons, and a linear regression model served to estimate the influence of the number of days patients were treated with LA on the studied parameters. LA treatment was associated with a significant decrease of total cholesterol (TC), LDL-C, HDL-C, and apoB, in both HeFH and HoFH patients, after single apheresis and in a long-term period during the monitored interval of 15 years. Biomarkers of inflammation and endothelial dysfunction were reduced for soluble endoglin, hsCRP, and MCP-1, and sP-selectin after each procedure in some HeFH and HoFH patients. Conclusions LA treatment up to 15 years, reduced cholesterol levels, levels of biomarkers related to endothelial dysfunction, and inflammation not only after each procedure but also in the long-term evaluation in FH patients. We propose that long-term LA treatment improves lipid profile and endothelial dysfunction in familial hypercholesterolemia patients, suggesting a promising improvement in cardiovascular prognosis in most FH patients.

The aim of our work was to investigate the effect of amitriptyline, citalopram and venlafaxine on the heart during ischemic- reperfusion (l-R) injury. Amitriptyline prolonged both QRS complex and QTc interval duration; citalopram and venlafaxine prolonged only QTc interval duration. Amitriptyline worked most proarrhythmogenic, citalopram least; venlafaxine increased the heart rate during ischemia; however, prolonged QTc interval at the beginning of reperfusion was followed by serious dysrhythmias.