Endothelial damage and stem cell repair in atherosclerosis

Inhibition of circ_0000231 suppresses oxidized low density lipoprotein-induced apoptosis, autophagy and inflammation in human umbilical vein endothelial cells by regulating miR-590-5p/PDCD4 axis

BACKGROUND

Circular RNAs (circRNAs) are the emerging informative RNAs, involved in cardiovascular diseases including atherosclerosis (AS). Endothelial injury is the initial qualitative change of AS. Thus, the objective of this study was to confirm the dysregulation and mechanism of circ_0000231 in cell model of AS at early stage in human umbilical vein endothelial cells (HUVECs) induced by oxidized low-density lipoprotein (ox-LDL).

METHODS

The expression of circ_0000231, miR-590-5p and programmed cell death 4 (PDCD4) was detected using real-time quantitative PCR and western blot. Cell injury was measured with MTT, flow cytometry, caspase-3 activity assay and enzyme-linked immunosorbent assay (ELISA). The interaction among circ_0000231, miR-590-5p and PDCD4 was validated by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) and pull-down assays.

RESULTS

Stress ox-LDL decreased cell viability, and increased apoptosis rate and caspase-3 activity in HUVECs in a dose- and time-dependent manner in concomitant with promotions of interleukin-6, interleukin-1β, tumor necrosis factor-α, LC3-II/I and Beclin-1 levels. Besides, circ_0000231 and PDCD4 expressions were upregulated, and miR-590-5p was downregulated in ox-LDL-stimulated HUVECs. Functionally, knockdown of circ_0000231 and overexpression of miR-590-5p could suppress ox-LDL-elicited above effects on apoptosis, autophagy and inflammatory response, accompanied with PDCD4 downregulation. Physically, miR-590-5p could directly interact with circ_0000231 and PDCD4.

CONCLUSION

Downregulation of circ_0000231 suppresses HUVECs from ox-LDL-induced injury partially through regulating miR-590-5p/PDCD4 axis via competing endogenous RNA mechanism, showing a novel potential target for the pathology and treatment of endothelial injury in AS.

Dynamics of Endothelial Cell Generation and Turnover in Arteries During Homeostasis and Diseases

BACKGROUND

Endothelial cell (EC) generation and turnover by self-proliferation contributes to vascular repair and regeneration. The ability to accurately measure the dynamics of EC generation would advance our understanding of cellular mechanisms of vascular homeostasis and diseases. However, it is currently challenging to evaluate the dynamics of EC generation in large vessels such as arteries because of their infrequent proliferation.

METHODS

By using dual recombination systems based on Cre-loxP and Dre-rox, we developed a genetic system for temporally seamless recording of EC proliferation in vivo. We combined genetic recording of EC proliferation with single-cell RNA sequencing and gene knockout to uncover cellular and molecular mechanisms underlying EC generation in arteries during homeostasis and disease.

RESULTS

Genetic proliferation tracing reveals that ≈3% of aortic ECs undergo proliferation per month in adult mice during homeostasis. The orientation of aortic EC division is generally parallel to blood flow in the aorta, which is regulated by the mechanosensing protein Piezo1. Single-cell RNA sequencing analysis reveals 4 heterogeneous aortic EC subpopulations with distinct proliferative activity. EC cluster 1 exhibits transit-amplifying cell features with preferential proliferative capacity and enriched expression of stem cell markers such as Sca1 and Sox18. EC proliferation increases in hypertension but decreases in type 2 diabetes, coinciding with changes in the extent of EC cluster 1 proliferation. Combined gene knockout and proliferation tracing reveals that Hippo/vascular endothelial growth factor receptor 2 signaling pathways regulate EC proliferation in large vessels.

CONCLUSIONS

Genetic proliferation tracing quantitatively delineates the dynamics of EC generation and turnover, as well as EC division orientation, in large vessels during homeostasis and disease. An EC subpopulation in the aorta exhibits more robust cell proliferation during homeostasis and type 2 diabetes, identifying it as a potential therapeutic target for vascular repair and regeneration.

Chuanzhitongluo capsule ameliorates microcirculatory dysfunction in rats: Efficacy evaluation and metabolic profiles

Background: Ischemic stroke is a leading cause of mortality and disability worldwide. Microcirculatory dysfunction is the foremost hindrance for a good clinical prognosis in ischemic stroke patients. Clinical researches show that Chuanzhitongluo capsule (CZTL) has a curative effect during the recovery period of ischemic stroke, which contributes to a good prognosis. However, it is not known whether CZTL treats ischemic stroke by ameliorating microcirculation dysfunction.

Objective: In this study, we investigated the influence of CZTL on microcirculation and its underlying mechanism.

Methods: A rat model of acute microcirculatory dysfunction was established by stimuli of adrenaline and ice water. The microcirculatory damage in model rats and the efficacy of CZTL were assessed by detecting laser speckle contrast imaging, coagulation function, hemorheology, vasomotor factor and microcirculation function. The potential mechanism of CZTL action was explored by the untargeted metabolomic analysis based on ultra-performance liquid chromatography-quadrupole-time of flight-mass spectrometry.

Results: Laser speckle contrast imaging showed that model rats suffered low perfusion in ears, feet and tails, and CZTL treatment increased microcirculatory blood flow. Coagulation function detection results showed that CZTL diminished the reduction of thrombin time, prothrombin time, activated partial thromboplastin time and the elevated fibrinogen level caused by acute microcirculatory dysfunction. Furthermore, CZTL could recover the increased blood viscosity as well as the abnormal vasomotor and microcirculation function in rats with acute microcirculatory dysfunction. Metabolomics analysis indicated that CZTL might regulate sphingolipid metabolism and arachidonic acid metabolism to exert protective effects on microcirculation.

Conclusion: These results elucidated that CZTL was highly effective against microcirculatory dysfunction and its potential mechanisms related with the modulation of sphingolipid and arachidonic acid metabolic pathways. The present study provided a new perspective on the clinical application of CZTL, and it contribute to explore novel therapeutic drug against microcirculatory dysfunction.

SESN1 attenuates the Ox‑LDL‑induced inflammation, apoptosis and endothelial‑mesenchymal transition of human umbilical vein endothelial cells by regulating AMPK/SIRT1/LOX1 signaling

Endothelial cells are an important component of the heart and vasculature and form a crucial link between the cardiovascular system and the immune system. Sestrin 1 (SESN1) has an important role in atherosclerosis by inhibiting NOD-like receptor family pyrin domain containing 3 inflammasome activation. However, whether SESN1 is involved in human umbilical vein endothelial cell (HUVEC) injury caused by atherosclerosis has remained to be elucidated. The present study aimed to investigate the functions of SESN1 in the inflammatory response, apoptosis and endothelial-mesenchymal transition (EndMT) of HUVECs following stimulation with oxidized low-density lipoprotein (Ox-LDL). SESN1 expression at the mRNA and protein levels was detected using reverse transcription-quantitative PCR (RT-qPCR) and western blot analysis. Following SESN1 overexpression in Ox-LDL-stimulated HUVECs, cell viability was determined using a Cell Counting Kit-8 assay. Terminal deoxynucleotidyl transferase-mediated nick-end labeling staining was employed to detect cell apoptosis and western blot analysis was used to determine the levels of apoptosis-related proteins. RT-qPCR, ELISA and western blot were utilized to determine the levels of inflammatory factors. Immunofluorescence staining, RT-qPCR and western blot analysis were employed to assess the EndMT of Ox-LDL-stimulated HUVECs. The results revealed that SESN1 exhibited a low expression in HUVECs following Ox-LDL stimulation. SESN1 overexpression suppressed inflammation, apoptosis and EndMT in Ox-LDL-induced HUVECs. In addition, SESN1 stimulated adenosine monophosphate-activated protein kinase catalytic subunit α1/sirtuin 1 signaling to suppress Ox-LDL receptor-1 expression. An AMPK and SIRT1 inhibitor reversed the effects of SESN1 overexpression on the inflammatory response, apoptosis and EndMT of HUVECs exposed to Ox-LDL. Taken together, the present study demonstrated that SENS1 exerts a suppressive effect on Ox-LDL-induced inflammation, apoptosis and EndMT of HUVECs, suggesting that SENS1 may be used as a novel biomarker for endothelial injury-related disorders.

Effect of oral intake of royal jelly on endothelium function in hemodialysis patients: study protocol for multicenter, double-blind, randomized control trial

Background

Hemodialysis (HD) is a common renal replacement therapy for patients with renal failure. Cardiovascular and cerebrovascular diseases are known to shorten survival periods and worsen the quality of life of HD patients. Atherosclerosis is a major cause of vascular diseases, and various factors such as abnormality of lipid metabolism and increased macrophage activity, oxidative stress, and endothelial dysfunction are associated with its pathogenesis and progression. Further, endothelial stem cells (ESCs) have been reported to play important roles in endothelial functions. Royal jelly (RJ) affects atherosclerosis- and endothelial function-related factors. The main aim of this trial is to investigate whether oral intake of RJ can maintain endothelial function in HD patients. In addition, the effects of RJ intake on atherosclerosis, ESC count, inflammation, and oxidative stress will be analyzed.

Methods

This will be a multicenter, prospective, double-blind, randomized controlled trial. We will enroll 270 participants at Nagasaki Jin Hospital, Shinzato Clinic Urakami, and Maeda Clinic, Japan. The participants will be randomized into RJ and placebo groups. The trial will be conducted according to the principles of the Declaration of Helsinki, and all participants will be required to provide written informed consent. The RJ group will be treated with 3600 mg/day of RJ for 24 months, and the placebo group will be treated with starch for 24 months. The primary endpoint will be the change in flow-mediated dilation (FMD), a parameter of endothelium function, from the time before treatment initiation to 24 months after treatment initiation. The secondary and other endpoints will be changes in FMD; ESC count; serum levels of vascular endothelial cell growth factor, macrophage colony-stimulating factor, 8-hydroxydeoxyguanosine, and malondialdehyde; the incidence of cardiovascular diseases, cerebrovascular diseases, and stenosis of blood access; and safety.

Discussion

This trial will clarify whether oral intake of RJ can maintain endothelial function and suppress the progression of atherosclerosis in HD patients. In addition, it will clarify the effects of RJ on ESCs, oxidative stress, and angiogenic activity in blood samples.

Trial registration

The Japan Registry of Clinical Trials jRCTs071200031.  Registered on 7 December 2020.

MiR-200c-3p promotes ox-LDL-induced endothelial to mesenchymal transition in human umbilical vein endothelial cells through SMAD7/YAP pathway

BACKGROUND

Endothelial to mesenchymal transition (EndMT) participates in the progression of atherosclerosis (AS). MiR-200c-3p has been implicated in EndMT. However, the functional role of miR-200c-3p in AS remains largely unknown. Here, we demonstrated the critical role of miR-200c-3p in regulating EndMT in AS.

METHODS

ApoE-/- mice were fed with high-fat diet to establish AS mouse model, and human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL) to mimic AS cell model. The expression of miR-200c-3p, SMAD7 and YAP in ApoE-/- mice and HUVECs was detected by quantitative real-time PCR. Rhodamine phalloidin staining and Western blot were performed to observe cell morphology and EndMT marker expression of HUVECs. Luciferase reporter assay and Co-Immunoprecipitation were performed to verify the relationship among miR-200c-3p, SMAD7, and YAP.

RESULTS

MiR-200c-3p was highly expressed, and SMAD7 and YAP were down-regulated in the aortic tissues of ApoE-/- mice and ox-LDL-treated HUVECs. MiR-200c-3p overexpression promoted the transformation of ox-LDL-treated HUVECs from cobblestone-like epithelial phenotype to a spindle-like mesenchymal phenotype. Meanwhile, miR-200c-3p up-regulation repressed the expression of endothelial markers CD31 and vWF and promoted the expression of mesenchymal markers α-SMA and vimentin in the ox-LDL-treated HUVECs. MiR-200c-3p inhibited SMAD7 and YAP expression by interacting with 3' untranslated region of SMAD7. Moreover, miR-200c-3p promoted EndMT in ox-LDL-treated HUVECs by inhibiting SMAD7/YAP pathway.

CONCLUSION

This work demonstrated that MiR-200c-3p promoted ox-LDL-induced EndMT in HUVECs through SMAD7/YAP pathway, which may be important for the onset of atherosclerosis.

Factors Affecting the Re-Endothelialization of Endothelial Progenitor Cell

The vascular endothelium, which plays an essential role in maintaining the normal shape and function of blood vessels, is a natural barrier between the circulating blood and the vascular wall tissue. The endothelial damage can cause vascular lesions, such as atherosclerosis and restenosis. After the vascular intima injury, the body starts the endothelial repair (re-endothelialization) to inhibit the neointimal hyperplasia. Endothelial progenitor cell is the precursor of endothelial cells and plays an important role in the vascular re-endothelialization. However, re-endothelialization is inevitably affected in vivo and in vitro by factors, which can be divided into two types, namely, promotion and inhibition, and act on different links of the vascular re-endothelialization. This article reviews these factors and related mechanisms.

Treatment of atherosclerosis through transplantation of endothelial progenitor cells overexpressing dimethylarginine dimethylaminohydrolase (DDAH) in rabbits

BACKGROUND

Endothelial dysfunction is a key event in the development of vascular diseases, including atherosclerosis. Endothelial progenitor cells (EPCs) play an important role in vascular repair. Decreased dimethylarginine dimethylaminohydrolase (DDAH) activity is observed in several pathological conditions, and it is associated with an increased risk of vascular disease. We hypothesized that bone marrow-derived EPCs and combination therapy with DDAH2-EPCs could reduce plaque size and ameliorate endothelial dysfunction in an atherosclerosis rabbit model.

METHOD

Four groups of rabbits (n = 8 per group) were subjected to a hyperlipidemic diet for a month. After establishing the atherosclerosis model, rabbits received 4 × 10⁶ EPC, EPCs expressing DDAH2, through femoral vein injection, or saline (the control group with basic food and the untreated group). One month after transplantation, plaque thickness, endothelial function, oxidative stress, and inflammatory mRNAs, DDAH, and eNOS function were assessed.

RESULTS

DDAH2-EPCs transplantation (p < 0.05) and EPCs transplantation (p < 0.05) were both associated with a reduction in plaque size compared to the control saline injection. The antiproliferative and antiatherogenic effects of EPCs were further enhanced by the overexpression of DDAH2 (p < 0.05, DDAH2-EPCs vs. EPCs). Furthermore, DDAH2-EPCs transplantation significantly increased endothelium integrity compared to the EPCs transplantation.

CONCLUSION

Transplantation of EPCs overexpressing DDAH2 may enhance the repair of injured endothelium by reducing inflammation and restoring endothelial function. Therefore, pCMV6-mediated DDAH2 gene-transfected EPCs are a potentially valuable tool for the treatment of atherosclerosis.

Blood pressure control is not enough to normalize endothelial repair by progenitor cells

Patients presenting with classical cardiovascular risk factors within acceptable or average value ranges often develop cardiovascular disease, suggesting that other risk factors need to be considered. Considering that endothelial progenitor cells (EPCs) contribute to endothelial repair, we investigated whether EPCs might be such a factor. We compared the ability of peripheral blood EPCs to attach to extracellular matrix proteins and to grow and function in culture, between controlled hypertensive patients exhibiting a Framingham score (FS) of <10% while showing severe vascular impairment (intima-media thickness/diameter, carotid-femoral pulse wave velocity, brachial artery flow-mediated dilation, carotid and femoral atherosclerotic plaque presence; vulnerable group, N = 30) and those with an FS of ≥10% and scarce vascular changes (protected group, N = 30). When compared with vulnerable patients, protected patients had significantly higher early and late-EPC and early and late-tunneling nanotube (TNT) numbers. Significant negative associations were found between vascular damage severity and early EPC, late-EPC, or late-TNT numbers, whereas EPC or TNT numbers and patient characteristics or cardiovascular risk factors were not associated. Except for protected patients, in all controlled hypertensive patients, early and late-EPC and early and late-TNT counts were significantly lower than those in the normotensive subjects studied (N = 30). We found that the disparity in vascular status between patients presenting with both an FS of ≥10% and scarce vascular changes and those presenting with both an FS of <10% and severe vascular impairment is related to differences in peripheral blood EPC and TNT numbers. These observations support the role of EPCs as contributors to vascular injury repair and suggest that EPC numbers may be a potential cardiovascular risk factor to be included in the FS calculation.NEW & NOTEWORTHY As individuals who present with risk factors within acceptable or average value ranges often develop cardiovascular (CV) disease, it has been suggested that other CV risk factors need to be considered in addition to those that are commonly combined in the Framingham score (FS) to estimate the risk of general CV disease. We investigated whether peripheral endothelial progenitor cells (EPCs) and tunneling nanotubes (TNTs) deserve to be considered. Here we report that EPCs and TNTs are significantly lower in controlled hypertensive patients versus normotensive subjects and that the disparity in vascular status between patients presenting with an FS of ≥10% with scarce vascular changes and those presenting with an FS of <10% with severe vascular impairment is related to differences in EPC and TNT numbers. These data point to EPC and TNT numbers as potential CV risk factors to be included in the FS calculation.

Demographic and clinical predictors of multiple intracranial aneurysms in patients with subarachnoid hemorrhage

OBJECTIVE

Pathophysiological differences that underlie the development and subsequent growth of multiple aneurysms may exist. In this study, the authors assessed the factors associated with the occurrence of multiple aneurysms in patients presenting with aneurysmal subarachnoid hemorrhage (SAH).

METHODS

Consecutive patients presenting with aneurysmal SAH between 1996 and 2012 were prospectively enrolled in the Subarachnoid Hemorrhage Outcome Project. Patients harboring 1, 2, or 3 or more aneurysms were stratified into groups, and the clinical and radiological characteristics of each group were compared using multivariate logistic regression.

RESULTS

Of 1277 patients with ruptured intracranial aneurysms, 890 had 1 aneurysm, 267 had 2 aneurysms, and 120 had 3 or more aneurysms. On multinomial regression using the single-aneurysm cohort as base case, risk factors for patients presenting with 2 aneurysms were female sex (relative risk ratio [RRR] 1.80, p < 0.001), higher body mass index (BMI) (RRR 1.02, p = 0.003), more years of smoking (RRR = 1.01, p = 0.004), and black race (RRR 1.83, p = 0.001). The risk factors for patients presenting with 3 or more aneurysms were female sex (RRR 3.10, p < 0.001), higher BMI (RRR 1.03, p < 0.001), aneurysm in the posterior circulation (RRR 2.59, p < 0.001), and black race (RRR 2.15, p = 0.001). Female sex, longer smoking history, aneurysms in the posterior circulation, BMI, and black race were independently associated with the development of multiple aneurysms in our adjusted multivariate multinomial model.

CONCLUSIONS

Significant demographic and clinical differences are found between patients presenting with single and multiple aneurysms in the setting of aneurysmal SAH. These predictors of multiple aneurysms likely reflect a predisposition toward inflammation and endothelial injury.

A Cytokine-Like Protein Dickkopf-Related Protein 3 Is Atheroprotective

Supplemental Digital Content is available in the text.

Background:

Dickkopf-related protein 3 (DKK3) is a secreted protein that is involved in the regulation of cardiac remodeling and vascular smooth muscle cell differentiation, but little is known about its role in atherosclerosis.

Methods:

We tested the hypothesis that DKK3 is atheroprotective using both epidemiological and experimental approaches. Blood DKK3 levels were measured in the Bruneck Study in 2000 (n=684) and then in 2005 (n=574). DKK3-deficient mice were crossed with apolipoprotein E^-/- mice to evaluate atherosclerosis development and vessel injury-induced neointimal formation. Endothelial cell migration and the underlying mechanisms were studied using in vitro cell culture models.

Results:

In the prospective population-based Bruneck Study, the level of plasma DKK3 was inversely related to carotid artery intima-media thickness and 5-year progression of carotid atherosclerosis independently from standard risk factors for atherosclerosis. Experimentally, we analyzed the area of atherosclerotic lesions, femoral artery injury-induced reendothelialization, and neointima formation in both DKK3^-/-/apolipoprotein E^-/- and DKK3^+/+/apolipoprotein E^-/- mice. It was demonstrated that DKK3 deficiency accelerated atherosclerosis and delayed reendothelialization with consequently exacerbated neointima formation. To explore the underlying mechanisms, we performed transwell and scratch migration assays using cultured human endothelial cells, which exhibited a significant induction in cell migration in response to DKK3 stimulation. This DKK3-induced migration activated ROR2 and DVL1, activated Rac1 GTPases, and upregulated JNK and c-jun phosphorylation in endothelial cells. Knockdown of the ROR2 receptor using specific siRNA or transfection of a dominant-negative form of Rac1 in endothelial cells markedly inhibited cell migration and downstream JNK and c-jun phosphorylation.

Conclusions:

This study provides the evidence for a role of DKK3 in the protection against atherosclerosis involving endothelial migration and repair, with great therapeutic potential implications against atherosclerosis.

Suppression of NADPH oxidase attenuates hypoxia-induced dysfunctions of endothelial progenitor cells

NADPH oxidases (NOX) - derived reactive oxygen species (ROS) contribute to oxidative injury in hypoxia-induced pulmonary arterial hypertension. This study aims to evaluate the status of NOX in endothelial progenitor cells (EPCs) under hypoxic condition and to determine whether NOX inhibitors could attenuate hypoxia-induced dysfunctions of EPCs. EPCs were isolated from peripheral blood of SD rats and subjected to hypoxia (O₂/N₂/CO₂, 1/94/5) for 24 h. The cells were collected for β-galactosidase or Hoechst staining, or for functional analysis (migration, adhesion and tube formation). The NOX expression, activity and H₂O₂ content in EPCs were measured. The results showed that hypoxia treatment promoted EPC senescence and apoptosis, accompanied by the deteriorated functions of EPCs (the reduced abilities in adhesion, migration and tube formation), as well as an increase in NOX2 and NOX4 expression, NOX activity and H₂O₂ production, these phenomena were attenuated by NOX inhibitors. Furthermore, administration of catalase could also improve the functions of hypoxia-treated EPCs. Based on these observations, we conclude that NOX-derived ROS contributes to the dysfunctions of EPCs under hypoxic condition. Thus, suppression of NOX may provide a novel strategy to improve endothelial functions in hypoxia-relevant diseases.

Dysfunction of endothelial progenitor cells in hyperlipidemic rats involves the increase of NADPH oxidase derived reactive oxygen species production

NADPH oxidase (NOX) is a major source of reactive oxygen species (ROS) in the body and it plays a key role in mediation of oxidative injury in the cardiovascular system. The purposes of this study are to evaluate the status of NOX in endothelial progenitor cells (EPCs) of hyperlipidemic rats and to determine whether NOX-derived ROS promotes the dysfunction of EPCs. The rats were fed on a high-fat diet for 8 weeks to establish a hyperlipidemic rat model, which showed the increased plasma lipids and the impaired functions of circulating EPCs (including the reduced abilities in migration and adhesion) accompanied by an increase in NOX activity and ROS production. Next, EPCs were isolated from normal rats and they were treated with oxidized low-density lipoprotein (ox-LDL) (100 μg/mL) for 24 h to induce a dysfunctional model in vitro. In agreement with our findings in vivo, ox-LDL treatment increased the dysfunctions of EPCs concomitant with an increase in NOX activity and ROS production; these phenomena were reversed by the NOX inhibitor. Based on these observations, we conclude that NOX-derived ROS involved in the dysfunctions of circulating EPCs in hyperlipidemic rats and inhibition of NOX might provide a novel strategy to improve EPC functions in hyperlipidemia.

Tanshinol protects human umbilical vein endothelial cells against hydrogen peroxide‑induced apoptosis

The present study was designed to investigate the effect of tanshinol on hydrogen peroxide (H2O2)‑induced apoptosis in human umbilical vein endothelial cells (HUVECs), and to determine the underlying mechanisms. HUVECs were pre‑incubated with tanshinol (25‑200 µM) for 24 h, followed by an incubation with 600 µM H2O2 for 6 h. The cell viability was assessed using MTT reagent and the level of cell death was determined by measuring lactate dehydrogenase (LDH) activity. Superoxide dismutase (SOD) activity, levels of malondialdehyde (MDA), reactive oxygen species (ROS) production and NADPH oxidase activity were measured spectrophotometrically using commercially available kits. The apoptotic rate of the HUVECs was detected using Annexin‑V/propidium iodide (PI) staining, followed by flow cytometry analysis using a fluorescence microscope. The protein expression of SOD‑1, SOD‑2, B‑cell lymphoma‑2 (Bcl‑2), cytochrome c and caspase‑3 was determined by western blot analysis. Pretreatment with tanshinol resulted in a significant increase in the cellular viability of HUVECs and SOD activity, and a decrease of cell apoptosis, MDA levels and ROS production, induced by H2O2. These findings were accompanied by the upregulation of Bcl‑2 protein expression, reduction in the release of cytochrome c from the mitochondria to the cytosol and a downregulation of caspase‑3 protein expression. This study showed that tanshinol protects against atherosclerosis by preventing H2O2‑induced apoptosis of HUVECs. These effects appear to be mediated by enhancing the antioxidant defenses and preserving the mitochondrial function of the cells.

[In vitro study over statins effects on cellular growth curves and its reversibility with mevalonate]

HMG-CoA-Reductase inhibitors, also known as statins, are currently the most powerful cholesterol-lowering drugs available on the market. Clinical trials and experimental evidence suggest that statins have heavy anti-atherosclerotic effects. These are in part consequence of lipid lowering but also result from pleiotropic actions of the drugs. These so-called pleiotropic properties affect various aspects of cell function, inflammation, coagulation, and vasomotor activity. These effects are mediated either indirectly through LDL-c reduction or via a direct effect on cellular functions. Although many of the pleiotropic properties of statins may be a class effect, some may be unique to certain agents and account for differences in their pharmacological activity. So, although statins typically have similar effects on LDL-c levels, differences in chemical structure and pharmacokinetic profile can lead to variations in pleiotropic effects. In this paper we analize the in vitro effects of different statins over different cell lines from cells implicated in atherosclerotic process: endothelial cells, fibroblasts, and vascular muscular cells. In relation with our results we can proof that the effects of different dosis of different statins provides singular effects over growth curves of different cellular lines, a despite of a class-dependent effects. So, pleiotropic effects and its reversibility with mevalonate are different according with the molecule and the dosis.

Endothelial cells overexpressing IL-8 receptor reduce cardiac remodeling and dysfunction following myocardial infarction

The endothelium is a dynamic component of the cardiovascular system that plays an important role in health and disease. This study tested the hypothesis that targeted delivery of endothelial cells (ECs) overexpressing neutrophil membrane IL-8 receptors IL8RA and IL8RB reduces acute myocardial infarction (MI)-induced left ventricular (LV) remodeling and dysfunction and increases neovascularization in the area at risk surrounding the infarcted tissue. MI was created by ligating the left anterior descending coronary artery in 12-wk-old male Sprague-Dawley rats. Four groups of rats were studied: group 1: sham-operated rats without MI or EC transfusion; group 2: MI rats with intravenous vehicle; group 3: MI rats with transfused ECs transduced with empty adenoviral vector (Null-EC); and group 4: MI rats with transfused ECs overexpressing IL8RA/RB (1.5 × 10⁶ cells post-MI). Two weeks after MI, LV function was assessed by echocardiography; infarct size was assessed by triphenyltetrazolium chloride (live tissue) and picrosirus red (collagen) staining, and capillary density and neutrophil infiltration in the area at risk were measured by CD31 and MPO immunohistochemical staining, respectively. When compared with the MI + vehicle and MI-Null-EC groups, transfusion of IL8RA/RB-ECs decreased neutrophil infiltration and pro-inflammatory cytokine expression and increased capillary density in the area at risk, decreased infarct size, and reduced MI-induced LV dysfunction. These findings provide proof of principle that targeted delivery of ECs is effective in repairing injured cardiac tissue. Targeted delivery of ECs to infarcted hearts provides a potential novel strategy for the treatment of acute MI in humans.

An intronic miRNA regulates expression of the human endothelial nitric oxide synthase gene and proliferation of endothelial cells by a mechanism related to the transcription factor SP-1

OBJECTIVE

This study was to investigate the molecular mechanisms underlying the 27nt-miRNA-mediated regulation of expression of the endothelial nitric oxide synthase (eNOS) gene.

METHODS

Cell lines overexpressing 27nt-miRNA or its mutant were established by transfecting the miRNA expression vector into the endothelial cells. eNOS mRNA and protein expression were examined by RT-PCR and Western Blotting, respectively. Luciferase activity reporter system was used to study the target of 27nt-miRNA.

RESULTS

The results showed that overexpression of 27nt-miRNA significantly inhibited eNOS mRNA level and protein expression, and reduced the eNOS transcriptional efficiency. Such inhibitory effects of 27nt-miRNA were attenuated by the sequence mutations in 27nt-miRNA. Interestingly, the transcription factor SP-1 expression was reduced by 27nt-miRNA. Meanwhile, overxpression of SP-1 protein partially restored eNOS expression, and rescued the 27nt-miRNA-mediated reduction of endothelial cell proliferation. Moreover, certain sites in the SP-1 mRNA were found to be the direct target of 27nt-miRNA by a luciferase reporter system.

CONCLUSIONS

These results demonstrate that the 27nt-miRNA suppresses eNOS gene expression and SP-1 expression in vascular endothelial cells. The 27nt-miRNA directly target to SP-1 mRNA, thereby contributing to proliferation of endothelial cells.

Study of endothelial cell apoptosis using fluorescence resonance energy transfer (FRET) biosensor cell line with hemodynamic microfluidic chip system

To better understand how hyperglycemia induces endothelial cell dysfunction under the diabetic conditions, a hemodynamic microfluidic chip system was developed. The system combines a caspase-3-based fluorescence resonance energy transfer (FRET) biosensor cell line which can detect endothelial cell apoptosis in real-time, post-treatment effect and with a limited cell sample, by using a microfluidic chip which can mimic the physiological pulsatile flow profile in the blood vessel. The caspase-3-based FRET biosensor endothelial cell line (HUVEC-C3) can produce a FRET-based sensor protein capable of probing caspase-3 activation. When the endothelial cells undergo apoptosis, the color of the sensor cells changes from green to blue, thus sensing apoptosis. A double-labeling fluorescent technique (yo pro-1 and propidium iodide) was used to validate the findings revealed by the FRET-based caspase sensor. The results show high rates of apoptosis and necrosis of endothelial cells when high glucose concentration was applied in our hemodynamic microfluidic chip combined with an exhaustive pulsatile flow profile. The two apoptosis detection techniques (fluorescent method and FRET biosensor) are comparable; but FRET biosensor offers more advantages such as real-time observation and a convenient operating process to generate more accurate and reliable data. Furthermore, the activation of the FRET biosensor also confirms the endothelial cell apoptosis induced by the abnormal pulsatile shear stress and high glucose concentration is through caspase-3 pathway. A 12% apoptotic rate (nearly a 4-fold increase compared to the static condition) was observed when the endothelial cells were exposed to a high glucose concentration of 20 mM under 2 h exhaustive pulsatile shear stress of 30 dyne cm(-2) and followed with another 10 h normal pulsatile shear stress of 15 dyne cm(-2). Therefore, the most important finding of this study is to develop a novel endothelial cell apoptosis detection method, which combines the microfluidic chip system and FRET biosensor. This finding may provide new insight into how glucose causes endothelial cell dysfunction, which is the major cause of diabetes-derived complications.

Irregular neointimal lining with prominent proliferative activity after carotid patch angioplasty: an autopsy case report

OBJECTIVE

Although the healing response after carotid balloon injury and carotid patch angioplasty injury has been well-documented in animal models, there is limited information about this process after carotid endarterectomy (CEA) in human patients.

CASE DESCRIPTION

We describe the autopsy results of a 79-year-old man who died 18 days after CEA with patch angioplasty. The treated carotid artery had an adequate luminal diameter. Elastica-Masson staining revealed that the treated portion was covered with neointima but the patch graft was exposed to the arterial lumen at 18 days after CEA. Immunohistochemistry staining for alpha-smooth muscle actin (α-SMA), von-Willebrand factor, and vascular endothelial growth factor receptor-2 revealed that the neointima was mainly composed of α-SMA-positive cells. In addition, the α-SMA-rich neointima had many more Ki-67-positive cells than did the internal carotid artery intima in the area beyond the CEA-treated portion.

CONCLUSIONS

This case report is the first to describe an entire carotid artery specimen in the acute stage after CEA with patch angioplasty. These findings suggest that an α-SMA-rich neointima with prominent proliferative activity covers the inner surface of the treated carotid artery, but patch grafts are left uncovered. The intrinsic arterial wall may have an important role in intimal regeneration after CEA, although the nature of the neointima and the mechanism by which it regulates proliferative activity remain unclarified.

A new correlation for inclusion of leaky junctions in macroscopic modeling of atherosclerotic lesion initiation

Vascular endothelium cells are the main barriers between vessel wall and blood flow; they play an essential role in the progression of atherosclerosis. Various experimental and computational studies have been carried out to identify the pathways and mechanisms by which Low Density Lipoprotein (LDL) transfers through the endothelium cells. The most conventional hypothesis in LDL transfer is the presence of leaky junctions. Leaky junctions are large pores in endothelium cells associated with cell mitosis or apoptosis. Although some studies have microscopically modeled leaky junctions, none however have evaluated their effects in a macroscopic level modeling. In this study, a new approach is proposed to consider the presence of the leaky junction as the main pathway in LDL transport from the lumen into the arterial wall. LDL transport in macroscopic scale is simulated in a simplified axisymmetric model and Staverman filtration coefficient (SFC) is used as a measurement criterion for estimating the amount of leaky junctions. According to the results, decreasing SFC corresponds to decreasing the resistance of endothelium cells. In other words, an increase in the number of leaky junctions causes an increase in the LDL concentration inside the arterial wall. Additionally, a new correlation is presented for evaluating the fraction of leaky junctions in the endothelial cells by comparing the results of macroscopic and microscopic models. This correlation accredits each SFC to a specified fraction of leaky junction in the endothelial cells. Therefore, it can be used for the inclusion of leaky junctions in the macroscopic modeling without incorporating any of the complications that are raised by the microscopic modeling studies. This correlation has important implications in the modeling of the atherosclerosis lesions propagation.

Pleiotropic effects of pitavastatin

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are established first line treatments for hypercholesterolaemia. In addition to the direct effects of statins in reducing concentrations of atherogenic low density lipoprotein cholesterol (LDL-C), several studies have indicated that the beneficial effects of statins may be due to some of their cholesterol-independent, multiple (pleiotropic) effects which may differ between different members of the class. Pitavastatin is a novel synthetic lipophilic statin that has a number of pharmacodynamic and pharmacokinetic properties distinct from those of other statins, which may underlie its potential pleiotropic benefits in reducing cardiovascular risk factors. This review examines the principal pleiotropic effects of pitavastatin on endothelial function, vascular inflammation, oxidative stress and thrombosis. The article is based on a systematic literature search carried out in December 2010, together with more recent relevant publications where appropriate. The available data from clinical trials and in vitro and animal studies suggest that pitavastatin is not only effective in reducing LDL-C and triglycerides, but also has a range of other effects. These include increasing high density lipoprotein cholesterol, decreasing markers of platelet activation, improving cardiac, renal and endothelial function, and reducing endothelial stress, lipoprotein oxidation and, ultimately, improving the signs and symptoms of atherosclerosis. It is concluded that the diverse pleiotropic actions of pitavastatin may contribute to reducing cardiovascular morbidity and mortality beyond that achieved through LDL-C reduction.

Humanin, a cytoprotective peptide, is expressed in carotid atherosclerotic [corrected] plaques in humans

OBJECTIVE

The mechanism of atherosclerotic plaque progression leading to instability, rupture, and ischemic manifestation involves oxidative stress and apoptosis. Humanin (HN) is a newly emerging endogenously expressed cytoprotective peptide. Our goal was to determine the presence and localization of HN in carotid atherosclerotic plaques.

METHODS AND RESULTS

Plaque specimens from 34 patients undergoing carotid endarterectomy were classified according to symptomatic history. Immunostaining combined with digital microscopy revealed greater expression of HN in the unstable plaques of symptomatic compared to asymptomatic patients (29.42±2.05 vs. 14.14±2.13% of plaque area, p<0.0001). These data were further confirmed by immunoblot (density of HN/β-actin standard symptomatic vs. asymptomatic 1.32±0.14 vs. 0.79±0.11, p<0.01). TUNEL staining revealed a higher proportion of apoptotic nuclei in the plaques of symptomatic patients compared to asymptomatic (68.25±3.61 vs. 33.46±4.46% of nuclei, p<0.01). Double immunofluorescence labeling revealed co-localization of HN with macrophages (both M1 and M2 polarization), smooth muscle cells, fibroblasts, and dendritic cells as well as with inflammatory markers MMP2 and MMP9.

CONCLUSIONS

The study demonstrates a higher expression of HN in unstable carotid plaques that is localized to multiple cell types within the plaque. These data support the involvement of HN in atherosclerosis, possibly as an endogenous response to the inflammatory and apoptotic processes within the atheromatous plaque.

An experimental study on MR imaging of atherosclerotic plaque with SPIO marked endothelial cells in a rabbit model

PURPOSE

To investigate how to label macrophages in atherosclerotic plaques with superparamagnetic iron oxide (SPIO) nanoparticles and trace SPIO with MR imaging.

MATERIALS AND METHODS

Atherosclerotic lesions of a rabbit model were induced by a combination of high-fat and high-cholesterol diet and subsequent endothelial abrasion of the abdominal aorta. SPIO particles were pretreated with poly-L-lysine. SPIO nanoparticles and SPIO-labeled human endothelial cells (ECV-304) were IV injected into model animals, respectively. The MRI scans and histopathological examination were performed 12 h and 24 h after the injection. The imaging and histopathological data were analyzed.

RESULTS

Prussian blue staining of the vessel specimens indicated that SPIO particles were not found in the atheroma but in the Kupffer's cells of the liver after SPIO injection. However, the accumulation of SPIO particles in the atheroma was confirmed in animals received SPIO-labeled endothelial cell transplantation. The best quality MR scan sequences of rabbit abdominal aorta were T(2) WI fat suppression, T(1) WI, and DIR series, on which of MR image had a higher quality. Signal loss of the original incrassate plaque in the vessel wall on T(2) WI was found in 6 of 10 animals received SPIO-labeled endothelial cell transplantation.

CONCLUSION

SPIO-labeled endothelial cells were superior to SPIO for MR imaging of atherosclerotic plaques.

Progenitor cells in arteriosclerosis: good or bad guys?

Accumulating evidence indicates that the mobilization and recruitment of circulating or tissue-resident progenitor cells that give rise to endothelial cells (ECs) and smooth muscle cells (SMCs) can participate in atherosclerosis, neointima hyperplasia after arterial injury, and transplant arteriosclerosis. It is believed that endothelial progenitor cells do exist and can repair and rejuvenate the arteries under physiologic conditions; however, they may also contribute to lesion formation by influencing plaque stability in advanced atherosclerotic plaque under specific pathologic conditions. At the same time, smooth muscle progenitors, despite their capacity to expedite lesion formation during restenosis, may serve to promote atherosclerotic plaque stabilization by producing extracellular matrix proteins. This profound evidence provides support to the hypothesis that both endothelial and smooth muscle progenitors may act as a double-edged sword in the pathogenesis of arteriosclerosis. Therefore, the understanding of the regulatory networks that control endothelial and smooth muscle progenitor differentiation is undoubtedly fundamental both for basic research and for improving current therapeutic avenues for atherosclerosis. We update the progress in progenitor cell study related to the development of arteriosclerosis, focusing specifically on the role of progenitor cells in lesion formation and discuss the controversial issues that regard the origins, frequency, and impact of the progenitors in the disease.

IL-17 induces apoptosis of vascular endothelial cells: a potential mechanism for human acute coronary syndrome

Th17 cells producing IL-17 are involved in the pathogenesis of atherosclerosis, but the underlying mechanisms remain unclear. In this study, we investigated the effects of IL-17 on human vascular endothelial cells and showed that IL-17 induced cell death of the vascular endothelial cells, which played a pivotal role in plaque destabilization triggering acute coronary syndrome (ACS). We showed that circulating Th17 cells and IL-17 increased in patients with ACS compared to the patients with stable angina or health individuals; the plasma levels of IL-6 increased but TGF-β decreased in ACS patients, exhibiting a positive and negative correlation with that of IL-17, respectively. Importantly, we uncovered that IL-17 promoted the production of von Willebrand factor by endothelial cells and induced endothelial apoptosis by activating caspase-3, caspase-9 and up-regulating the ratio of Bax/Bcl-2, indicating the function of IL-17 in vascular endothelial damage as a potential mechanism for the pathogenesis of human ACS.

Heat shock protein 60 and immune inflammatory responses in atherosclerosis

Hallmarks of inflammation in various cardiovascular diseases, notably atherosclerosis, have been observed for a long time. However, evidence for an (auto)antigen-driven process at these sites of inflammation has come forward only recently. Heat shock proteins (HSPs) have been identified as playing either immunologically mediated disease promoting or protective roles. HSP60 has been shown to trigger innate and adaptive immune responses that initiate the earliest still reversible inflammatory stage of atherosclerosis. HSP60 is structurally highly conserved and abundantly expressed by prokaryotic and eukaryotic cells under stressful conditions. Beneficial protective immunity to microbial HSP60 acquired by infection or vaccination and bona fide autoimmunity to biochemically altered autologous HSP60 is present in all humans. In vitro and in vivo experiments have demonstrated that classical atherosclerosis risk factors can act as endothelial stressors that provoke the simultaneous expression of adhesion molecules and of HSP60 in mitochondria, in cytoplasm, and on the cell surface, where it acts as a "danger signal" for cellular and humoral immune reactions. Hence, protective, preexisting anti-HSP60 immunity may have to be "paid for" by harmful (auto)immune cross-reactive attack on arterial endothelial cells maltreated by atherosclerosis risk factors. These experimentally and clinically proven findings are the basis for the autoimmune concept of atherosclerosis.