Transgenic human C-reactive protein affects oxidative stress but not inflammation biomarkers in the aorta of spontaneously hypertensive rats.

BACKGROUND: C-reactive protein (CRP) is an acute inflammatory protein detected in obese patients with metabolic syndrome. Moreover, increased CRP levels have been linked with atherosclerotic disease, congestive heart failure, and ischemic heart disease, suggesting that it is not only a biomarker but also plays an active role in the pathophysiology of cardiovascular diseases. Since endothelial dysfunction plays an essential role in various cardiovascular pathologies and is characterized by increased expression of cell adhesion molecules and inflammatory markers, we aimed to detect specific markers of endothelial dysfunction, inflammation, and oxidative stress in spontaneously hypertensive rats (SHR) expressing human CRP. This model is genetically predisposed to the development of the metabolic syndrome. METHODS: Transgenic SHR male rats (SHR-CRP) and non-transgenic SHR (SHR) at the age of 8 months were used. Metabolic profile (including serum and tissue triglyceride (TAG), serum insulin concentrations, insulin-stimulated incorporation of glucose, and serum non-esterified fatty acids (NEFA) levels) was measured. In addition, human serum CRP, MCP-1 (monocyte chemoattractant protein-1), and adiponectin were evaluated by means of ELISA, histological analysis was used to study morphological changes in the aorta, and western blot analysis of aortic tissue was performed to detect expression of endothelial, inflammatory, and oxidative stress markers. RESULTS: The presence of human CRP was associated with significantly decreased insulin-stimulated glycogenesis in skeletal muscle, increased muscle and hepatic accumulation of TAG and decreased plasmatic cGMP concentrations, reduced adiponectin levels, and increased monocyte chemoattractant protein-1 (MCP-1) levels in the blood, suggesting pro-inflammatory and presence of multiple features of metabolic syndrome in SHR-CRP animals. Histological analysis of aortic sections did not reveal any visible morphological changes in animals from both SHR and SHR-CRP rats. Western blot analysis of the expression of proteins related to the proper function of endothelium demonstrated significant differences in the expression of p-eNOS/eNOS in the aorta, although endoglin (ENG) protein expression remained unaffected. In addition, the presence of human CRP in SHR in this study did not affect the expression of inflammatory markers, namely p-NFkB, P-selectin, and COX2 in the aorta. On the other hand, biomarkers related to oxidative stress, such as HO-1 and SOD3, were significantly changed, indicating the induction of oxidative stress. CONCLUSIONS: Our findings demonstrate that CRP alone cannot fully induce the expression of endothelial dysfunction biomarkers, suggesting other risk factors of cardiovascular disorders are necessary to be involved to induce endothelial dysfunction with CRP.

Endoglin and soluble endoglin in liver sinusoidal endothelial dysfunction in vivo.

Liver sinusoidal endothelial cells (LSECs) play a crucial role in regulating the hepatic function. Endoglin (ENG), a transmembrane glycoprotein, was shown to be related to the development of endothelial dysfunction. In this study, we hypothesized the relationship between changes in ENG expression and markers of liver sinusoidal endothelial dysfunction (LSED) during liver impairment. Male C57BL/6J mice aged 9-12 weeks were fed with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet (intrahepatic cholestasis) or choline-deficient l-amino acid defined high-fat diet (CDAA-HFD) (non-alcoholic steatohepatitis (NASH)). Significant increases in liver enzymes, fibrosis, and inflammation biomarkers were observed in both cholestasis and NASH. Decreased p-eNOS/eNOS and VE-cadherin protein expression and a significant increase in VCAM-1 and ICAM-1 expression were detected, indicating LSED in both mouse models of liver damage. A significant reduction of ENG in the DDC-fed mice, while a significant increase of ENG in the CDAA-HFD group was observed. Both DDC and CDAA-HFD-fed mice showed a significant increase in MMP-14 protein expression, which is related to significantly increased levels of soluble endoglin (sENG) in the plasma. In conclusion, we demonstrated that intrahepatic cholestasis and NASH result in an altered ENG expression, predominantly in LSECs, suggesting a critical role of ENG expression for the proper function of liver sinusoids. Both pathologies resulted in elevated sENG levels, cleaved by MMP-14 expressed predominantly from LSECs, indicating sENG as a liver injury biomarker.

Regulation and role of endoglin in cholesterol-induced endothelial and vascular dysfunction in vivo and in vitro.

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-κB in HAECs. 7K-induced Eng expression was prevented by the treatment with 2-hydroxypropyl-ß-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.

High soluble endoglin levels do not induce changes in structural parameters of mouse heart.

A soluble form of endoglin (sEng) released into the circulation was suggested to be a direct inducer of endothelial dysfunction, inflammation and contributed to the development of hypertension by interfering with TGF-ß signaling in cardiovascular pathologies. In the present study, we assessed the hypothesis that high sEng level-induced hypertension via a possible sEng interference with TGF-ß signaling pathways may result in inflammatory, structural or fibrotic changes in hearts of Sol-Eng+ mice (mice with high levels of soluble endoglin) fed either chow or high-fat diet. Female Sol-Eng+ mice and their age matched littermates with low plasma levels of sEng were fed either chow or high-fat diet (HFD). Heart samples were subsequently analyzed by histology, qRT-PCR and Western blot analysis. In this study, no differences in myocardial morphology/hypertrophy and possible fibrotic changes between Sol-Eng+ mice and control mice were detected on both chow and HFD. The presence of sEng did not significantly affect the expression of selected members of TGF-ß signaling (membrane endoglin, TGFßRII, ALK-5, ALK-1, Id-1, PAI-1 and activated Smad proteins-pSmad 1,5 and pSmad 2,3), inflammation, heart remodeling (PDGFb, Col1A1) and endothelial dysfunction (VCAM-1, ICAM-1) in the hearts of Sol-Eng+ mice compared to control mice on both chow and high-fat diet. High levels of soluble endoglin did not affect microscopic structure (profibrotic and degenerative cardiomyocyte changes), and specific parts of TGF-ß signaling, endothelial function and inflammation in the heart of Sol-Eng+ mice fed both chow diet or HFD. However, we cannot rule out a possibility that a long-term chronic exposure (9 months and more) to soluble endoglin alone or combined with other cardiovascular risk factors may contribute to alterations of heart function and structure in Sol-Eng+ mice, which is the topic in our lab in ongoing experiments.

Soluble endoglin modulates the pro-inflammatory mediators NF-κB and IL-6 in cultured human endothelial cells.

AIMS: Endoglin is a transmembrane glycoprotein, that plays an important role in regulating endothelium. Proteolytic cleavage of membrane endoglin releases soluble endoglin (sEng), whose increased plasma levels have been detected in diseases related to the cardiovascular system. It was proposed that sEng might damage vascular endothelium, but detailed information about the potential mechanisms involved is not available. Thus, we hypothesized that sEng contributes to endothelial dysfunction, leading to a pro-inflammatory phenotype by a possible modulation of the TGF-ß and/or inflammatory pathways. MAIN METHODS: Human umbilical vein endothelial cells (HUVECs) and Human embryonic kidney cell line (HEK293T) were treated with different sEng concentration and time in order to reveal possible effect on biomarkers of inflammation and TGF-ß signaling. IL6 and NFκB reporter luciferase assays, quantitative real-time PCR analysis, Western blot analysis and immunofluorescence flow cytometry were used. KEY FINDINGS: sEng treatment results in activation of NF-κB/IL-6 expression, increased expression of membrane endoglin and reduced expression of Id-1. On the other hand, no significant effects on other markers of endothelial dysfunction and inflammation, including eNOS, peNOSS1177, VCAM-1, COX-1, COX-2 and ICAM-1 were detected. SIGNIFICANCE: As a conclusion, sEng treatment resulted in an activation of NF-κB, IL-6, suggesting activation of pro-inflammatory phenotype in endothelial cells. The precise mechanism of this activation and its consequence remains to be elucidated. A combined treatment of sEng with other cardiovascular risk factors will be necessary in order to reveal whether sEng is not only a biomarker of cardiovascular diseases, but also a protagonist of endothelial dysfunction.

High Levels of Soluble Endoglin Induce a Proinflammatory and Oxidative-Stress Phenotype Associated with Preserved NO-Dependent Vasodilatation in Aortas from Mice Fed a High-Fat Diet.

AIMS: A soluble form of endoglin (sEng) was proposed to participate in the induction of endothelial dysfunction in small blood vessels. Here, we tested the hypothesis that high levels of sEng combined with a high-fat diet induce endothelial dysfunction in an atherosclerosis-prone aorta. METHODS AND RESULTS: Six-month-old female and male transgenic mice overexpressing human sEng (Sol-Eng+) with low (Sol-Eng+low) or high (Sol-Eng+high) levels of plasma sEng were fed a high-fat rodent diet containing 1.25% cholesterol and 40% fat for 3 months. The plasma cholesterol and mouse sEng levels did not differ in the Sol-Eng+high and Sol-Eng+low mice. The expression of proinflammatory (P-selectin, ICAM-1, pNFκB and COX-2) and oxidative-stress-related markers (HO-1, NOX-1 and NOX-2) in the aortas of Sol-Eng+high female mice was significantly higher than in Sol-Eng+low female mice. Endothelium-dependent vasodilatation induced by acetylcholine was preserved better in the Sol-Eng+ high female mice than in the Sol-Eng+low female mice. CONCLUSION: These results suggest that high concentrations of sEng in plasma in combination with a high-fat diet induce the simultaneous activation of proinflammatory, pro-oxidative and vasoprotective mechanisms in mice aorta and the balance of these biological processes determines whether the final endothelial phenotype is adaptive or maladaptive.

Statin impact on disease activity and C-reactive protein concentrations in systemic lupus erythematosus patients: A systematic review and meta-analysis of controlled trials.

BACKGROUND AND PURPOSE: Efficacy and safety of statin therapy in patients with systemic lupus erythematosus (SLE) is controversial. The aim of this meta-analysis was to evaluate whether statin therapy affects SLE disease activity and systemic inflammation (C-reactive protein, CRP) according to the evidence from controlled clinical trials. EXPERIMENTAL APPROACH: A systematic review followed by a bibliographic search in Medline and SCOPUS (up to March 2015) was performed. Quantitative data synthesis was performed using a random-effects model and the generic inverse variance weighting method. Effect sizes were expressed as weighted mean difference (WMD) and 95% confidence interval (CI). KEY RESULTS: Meta-analysis of five controlled trials reporting statin impact on SLE disease activity did not suggest any significant effect of statin therapy on SLEDAI. Evaluation of seven controlled trials with reported effects on CRP levels suggested a significant reduction of plasma CRP concentrations in patients with SLE independent of the treatment duration. The effect size on plasma CRP concentrations was significant with lipophilic (atorvastatin) but not hydrophilic (pravastatin and rosuvastatin) statins. CONCLUSION AND IMPLICATIONS: The present results suggest that statin therapy is likely to be safe in patients with SLE. In addition, statin-treated SLE patients may benefit from CRP reduction in terms of managing severe cardiovascular complications associated with the disease.

Statin therapy and plasma cortisol concentrations: A systematic review and meta-analysis of randomized placebo-controlled trials.

This study aimed to perform a systematic review and meta-analysis of randomized controlled trials (RCTs) in order to calculate the effect size of statin therapy in changing plasma cortisol concentrations. Following a systematic search in Medline, SCOPUS, Web of Science and Google Scholar databases (by up to March 01, 2015), 7 eligible RCTs were selected. Random-effects meta-analysis suggested a significant increase in plasma cortisol concentrations following statin therapy (WMD: 6.34%, 95% CI: 1.80, 10.87, p=0.006). Subgroup analysis confirmed the significance of the effect with lipophilic statins comprising atorvastatin, simvastatin, and lovastatin (WMD: 7.00%, 95% CI: 2.21, 11.79, p=0.004) but not with hydrophilic statins (rosuvastatin and pravastatin) (WMD: 0.60%, 95% CI: -13.46, 14.66, p=0.933). In the meta-regression analysis, changes in plasma cortisol concentrations following statin therapy were found to be independent of treatment duration. Results of this meta-analysis of RCTs suggest a significant elevation in plasma cortisol levels following statin therapy.

Soluble endoglin, hypercholesterolemia and endothelial dysfunction.

A soluble form of endoglin (sEng) is known to be an extracellular domain of the full-length membrane endoglin, which is elevated during various pathological conditions related to vascular endothelium. In the current review, we tried to summarize a possible role of soluble endoglin in cardiovascular pathologies, focusing on its relation to endothelial dysfunction and cholesterol levels. We discussed sEng as a proposed biomarker of cardiovascular disease progression, cardiovascular disease treatment and endothelial dysfunction. We also addressed a potential interaction of sEng with TGF-ß/eNOS or BMP-9 signaling. We suggest soluble endoglin levels to be monitored, because they reflect the progression/treatment efficacy of cardiovascular diseases related to endothelial dysfunction and hypercholesterolemia. A possible role of soluble endoglin as an inducer of endothelial dysfunction however remains to be elucidated.

High soluble endoglin levels do not induce endothelial dysfunction in mouse aorta.

Increased levels of a soluble form of endoglin (sEng) circulating in plasma have been detected in various pathological conditions related to cardiovascular system. High concentration of sEng was also proposed to contribute to the development of endothelial dysfunction, but there is no direct evidence to support this hypothesis. Therefore, in the present work we analyzed whether high sEng levels induce endothelial dysfunction in aorta by using transgenic mice with high expression of human sEng. Transgenic mice with high expression of human sEng on CBAxC57Bl/6J background (Sol-Eng+) and age-matched transgenic littermates that do not develop high levels of human soluble endoglin (control animals in this study) on chow diet were used. As expected, male and female Sol-Eng+ transgenic mice showed higher levels of plasma concentrations of human sEng as well as increased blood arterial pressure, as compared to control animals. Functional analysis either in vivo or ex vivo in isolated aorta demonstrated that the endothelium-dependent vascular function was similar in Sol-Eng+ and control mice. In addition, Western blot analysis showed no differences between Sol-Eng+ and control mice in the protein expression levels of endoglin, endothelial NO-synthase (eNOS) and pro-inflammatory ICAM-1 and VCAM-1 from aorta. Our results demonstrate that high levels of soluble endoglin alone do not induce endothelial dysfunction in Sol-Eng+ mice. However, these data do not rule out the possibility that soluble endoglin might contribute to alteration of endothelial function in combination with other risk factors related to cardiovascular disorders.

Endoglin is not expressed with cell adhesion molecules in aorta during atherogenesis in apoE-deficient mice.

Endoglin (TGF-ß receptor III), has been demonstrated to affect vascular endothelium and atherosclerosis. Moreover, it was also demonstrated that endoglin is involved in inflammation and plays a role in leukocyte adhesion and transmigration in vitro and in vivo but not in atherosclerosis related vessels. In this study, we wanted to evaluate endoglin expression in two different parts of the aorta (heart aortic sinus and ascending aorta) and assess its potential simultaneous expression with cell adhesion molecules in non-atherosclerotic and atherosclerotic aortas of apoE-deficient mice. Ten-week-old female apolipoprotein E-deficient mice on a C57BL/6J background (n=24) were randomly subdivided into three groups and were fed either chow diet (for another two months) or Western type diet (for another two or four months). Immunohistochemical staining of endoglin, VCAM-1 and P-selectin in aortic sinus and ascending aorta was performed. Endoglin expression was detected only in endothelial cells and varied during atherogenic process in aorta but not in aortic sinus. Moreover, its expression seemed to be weaker in aorta when compared to aortic sinus and the positivity was detected only in endothelium covering atherosclerotic lesions but not in non-atherosclerotic endothelium regardless of the plaque size. Endoglin was not expressed with P selectin and VCAM-1 in aortic endothelium in any studied group. This study shows that endothelial expression of endoglin is related to the atherogenic process predominantly in aorta outside the heart. Moreover, endoglin is not localized with cell adhesion molecules involved in atherosclerosis, suggesting it might not participate in leukocyte accumulation in aorta of apoE-deficient mice during atherogenesis.

Cell adhesion molecules and eNOS expression in aorta of normocholesterolemic mice with different predispositions to atherosclerosis.

C57BL/6J (B6) mice were demonstrated to be the most susceptible and C3H/HeJ (C3H) mice the most resistant to development of atherosclerosis. We hypothesized, whether pro-atherogenic (P-selectin, VCAM-1, and ICAM-1) and anti-atherogenic (endoglin and eNOS) proteins are expressed differently in aorta before the onset of atherosclerosis in these two mouse strains. B6 mice (n = 16) and C3H mice (n = 16) sustained on either chow or cholesterol (1 %) diet for 8 weeks. Biochemical analysis of lipoprotein profile and Western blot analysis of P-selectin, VCAM-1, ICAM-1, eNOS, endoglin, peNOS and TGF-ßRII in aorta were performed. Western blot analysis revealed a lower expression of P-selectin by 7 %, VCAM-1 by 51 %, ICAM-1 by 6 %, and a higher expression of eNOS (by 18 %) in C3H mice in comparison with B6 mice after cholesterol diet. Further analysis revealed that cholesterol diet significantly increased the expression of endoglin (by 97 %), TGF-ßRII (by 50 %), eNOS (by 21 %) and peNOS (by 122 %) in C3H mice, but not in B6 mice. We propose that lower expression of P-selectin, VCAM-1 and ICAM-1 and higher expression of eNOS in vivo in aorta of C3H mice might represent another potential mechanism for C3H mice being less susceptible to atherosclerosis when compared to B6 mice. In addition, endoglin seems to be involved in an upregulation of eNOS only in C3H mice. Thus, we propose that aorta of C3H mice is less prone to the expression of pro-inflammatory and endothelial dysfunction markers when compared to B6 mice, regardless of lipoprotein profile and before any signs of atherosclerotic process.

Spirulina platensis and phycocyanobilin activate atheroprotective heme oxygenase-1: a possible implication for atherogenesis.

Spirulina platensis, a water blue-green alga, has been associated with potent biological effects, which might have important relevance in atheroprotection. We investigated whether S. platensis or phycocyanobilin (PCB), its tetrapyrrolic chromophore, can activate atheroprotective heme oxygenase-1 (Hmox1), a key enzyme in the heme catabolic pathway responsible for generation of a potent antioxidant bilirubin, in endothelial cells and in a mouse model of atherosclerosis. In vitro experiments were performed on EA.hy926 endothelial cells exposed to extracts of S. platensis or PCB. In vivo studies were performed on ApoE-deficient mice fed a cholesterol diet and S. platensis. The effect of these treatments on Hmox1, as well as other markers of oxidative stress and endothelial dysfunction, was then investigated. Both S. platensis and PCB markedly upregulated Hmox1 in vitro, and a substantial overexpression of Hmox1 was found in aortic atherosclerotic lesions of ApoE-deficient mice fed S. platensis. In addition, S. platensis treatment led to a significant increase in Hmox1 promoter activity in the spleens of Hmox-luc transgenic mice. Furthermore, both S. platensis and PCB were able to modulate important markers of oxidative stress and endothelial dysfunction, such as eNOS, p22 NADPH oxidase subunit, and/or VCAM-1. Both S. platensis and PCB activate atheroprotective HMOX1 in endothelial cells and S. platensis increased the expression of Hmox1 in aortic atherosclerotic lesions in ApoE-deficient mice, and also in Hmox-luc transgenic mice beyond the lipid lowering effect. Therefore, activation of HMOX1 and the heme catabolic pathway may represent an important mechanism of this food supplement for the reduction of atherosclerotic disease.

The role of endoglin in atherosclerosis.

Endoglin (CD 105, TGF-ß receptor III) is a homodimeric transmembrane glycoprotein that plays a regulatory role in TGF-ß signaling. Its functional role in the context of atherosclerosis has yet to be defined and should be stated here. Therefore, we focused on the role of endoglin in atherosclerosis in both humans and experimental animals. Endoglin expression was demonstrated in atherosclerotic vessels predominantly in endothelial cells and smooth muscle cells in various types of blood vessels in mice and humans, suggesting its participation in atherogenesis. Endoglin expression was also related to the expression of eNOS in endothelium, repair of the vessel wall, plaque neoangiogenesis, production of collagen and stabilization of atherosclerotic lesions. In addition, increased levels of soluble endoglin were associated with hypercholesterolemia, atherosclerosis, acute myocardial infarction and were related to inhibition of TGF-ß signaling in the vessel wall. Moreover, soluble endoglin levels were significantly lowered after a series of extracorporeal eliminations in patients with familial hypercholesterolemia. Additionally, statin treatment decreased levels of soluble endoglin and increased its expression in aorta, which was related to reduced atherosclerosis in mice. In conclusion, we propose that measurement of soluble endoglin might give information about progression of the atherosclerotic process or the efficacy of therapeutic interventions, which is the task that must be answered in clinical trials.

Activation of TGF-ß receptors and Smad proteins by atorvastatin is related to reduced atherogenesis in ApoE/LDLR double knockout mice.

AIM: Transforming growth factor-beta (TGF-ß) plays important role in atherogenesis via TGF-ß receptors and Smad proteins, which determine its signaling activity. In this study, we hypothesized, whether non-lipid related effects of atorvastatin, affect both endoglin/ALK-5/Smad2/eNOS and/or endoglin/ALK-1/Smad1/VEGF previously proposed pathways in ApoE/LDLR double knockout mice. METHODS: ApoE/LDLR double knockout mice were divided into two groups. The chow group (CHOW) (n =8) was fed with chow diet, while in the atorvastatin group (ATV) (n =8) atorvastatin was added to the chow diet at dose 50 mg/kg/day. Biochemical analyses of lipid profile, lesion area measurement, immunohistochemistry and Western blot analysis of endoglin, ALK-1, 5, phosphorylated and non-phosphorylated forms Smad-1, 2, VEGF and eNOS proteins in mice aorta were performed. RESULTS: Biochemical analysis of blood serum and morphometric analysis of aortic lesion size showed that atorvastatin treatment resulted in a significant increase of cholesterol levels and simultaneously in reduced lesion size in aortic sinus when compared to CHOW mice. Western blot analysis revealed that atorvastatin treatment significantly increase the expressions of endoglin by 102%, ALK-1 by 113%, ALK-5 by 296%, pSmad-1 by 202%, pSmad-2 by 34%, VEGF by 68% and eNOS by 687% as compared with CHOW mice. Immunofluorescence staining revealed endoglin coexpression with all studied markers that were increased by atorvastatin treatment mainly in endothelial cells covering atherosclerotic plaques. CONCLUSION: This study shows that atorvastatin treatment increases the expression of endoglin, ALK-1, ALK-5, phosphorylated forms of Smad1 and Smad2, VEGF and eNOS and reduces atherosclerotic lesion size beyond its lipid lowering effects. Therefore, we propose that endoglin related receptors and signal transducers might play protective role in atherogenesis.

Cholesterol effects on endoglin and its downstream pathways in ApoE/LDLR double knockout mice.

BACKGROUND: The aim of the study was to evaluate whether cholesterol-rich diet affects transforming growth factor-ß-RIII (endoglin) levels in blood and 2 endoglin-related pathways in the aorta of ApoE/LDLR double knockout mice. METHODS AND RESULTS: Mice were fed either chow diet (CHOW) (n=8) or by 1% cholesterol-rich diet (CHOL) (n=8). Biochemical analysis of cholesterol and endoglin levels in blood, lesion size area, immunohistochemistry and Western blot analysis in mice aortas were performed. Biochemical analysis showed that cholesterol-rich diet resulted in a significant increase of cholesterol and endoglin levels in serum, and increased plaque size in the aorta. In addition, a cholesterol-rich diet significantly decreased the expressions of endoglin by 92%, activin receptor-like kinase (ALK)-1 by 71%, p-Smad2 by 21%, and vascular endothelial growth factor (VEGF) by 37% when compared to CHOW mice, but ALK-5, p-Smad1, and endothelial nitric oxide synthase were not significantly affected. CONCLUSIONS: Hypercholesterolemia increases endoglin levels in blood and simultaneously decreases its expression in aorta, together with atherosclerosis protective markers p-Smad2 and VEGF, followed by increased plaque size. Inhibition of endoglin signaling might be one of the mechanisms responsible for the promoting of endothelial dysfunction and atherogenesis. Moreover, the monitoring of endoglin serum levels might represent an attractive blood marker of progression of disease; however, the precise source and role of endoglin in blood serum remains to be elucidated.

Endoglin as a possible marker of atorvastatin treatment benefit in atherosclerosis.

Endoglin (a type III TGF-ß receptor) is able to modulate ligand binding and signaling by association with the TGF-ß type I receptors (ALK-1 and ALK-5). In this study, we hypothesized whether atorvastatin treatment affects endoglin/ALK-1/p-Smad1/VEGF expression in the aorta and endoglin levels in serum in ApoE/LDLR double knockout mice. ApoE/LDLR double knockout mice were fed with a diet containing either 1% of cholesterol (CHOL) or cholesterol with atorvastatin (ATV) at a dose of 50mg/kg/day. Biochemical analysis of cholesterol levels and ELISA analysis of endoglin levels in serum, lesion area size, immunohistochemistry and Western blot analysis in mice aorta were performed. Atorvastatin treatment resulted in a significant decrease of total, VLDL and LDL cholesterol, atherosclerotic lesion size and endoglin serum levels in comparison with CHOL mice. On the other hand, atorvastatin treatment significantly increased the expressions of endoglin by 1431%, ALK-1 by 310%, p-Smad1 by 135% and VEGF by 62% in aorta when compared to CHOL mice. In conclusion, it has been demonstrated that atorvastatin increases endoglin/ALK-1/p-Smad1/VEGF expression in aorta and decreases the size of atherosclerotic lesions, suggesting that activation of this endothelial-protective pathway might support the antiatherogenic effects of atorvastatin. Moreover, atorvastatin concurrently decreased serum levels of endoglin suggesting that monitoring of endoglin levels in blood might represent an important marker of the progression and/or treatment of atherosclerosis.