Rho-kinase is involved in macrophage-mediated formation of coronary vascular lesions in pigs in vivo

Mechanisms of Coronary Artery Spasm

Recent clinical trials have highlighted that percutaneous coronary intervention in patients with stable angina provides limited additional benefits on top of optimal medical therapy. This has led to much more attention being paid to coronary vasomotion abnormalities regardless of obstructive or non-obstructive arterial segments. Coronary vasomotion is regulated by multiple mechanisms that include the endothelium, vascular smooth muscle cells (VSMCs), myocardial metabolic demand, autonomic nervous system and inflammation. Over the years, several animal models have been developed to explore the central mechanism of coronary artery spasm. This review summarises the landmark studies on the mechanisms of coronary vasospasm demonstrating the central role of Rho-kinase as a molecular switch of VSMC hypercontraction and the important role of coronary adventitial inflammation for Rho-kinase upregulation in VSMCs.

Statins change the cytokine profile in Trypanosoma cruzi-infected U937 macrophages and murine cardiac tissue through Rho-associated kinases inhibition

Introduction

Chronic Chagasic cardiomyopathy (CCC), caused by the protozoan Trypanosoma cruzi, is the most severe manifestation of Chagas disease.CCC is characterized by cardiac inflammation and fibrosis caused by a persistent inflammatory response. Following infection, macrophages secrete inflammatory mediators such as IL-1β, IL-6, and TNF-α to control parasitemia. Although this response contains parasite infection, it causes damage to the heart tissue. Thus, the use of immunomodulators is a rational alternative to CCC. Rho-associated kinase (ROCK) 1 and 2 are RhoA-activated serine/threonine kinases that regulate the actomyosin cytoskeleton. Both ROCKs have been implicated in the polarization of macrophages towards an M1 (pro-inflammatory) phenotype. Statins are FDA-approved lipid-lowering drugs that reduce RhoA signaling by inhibiting geranylgeranyl pyrophosphate (GGPP) synthesis. This work aims to identify the effect of statins on U937 macrophage polarization and cardiac tissue inflammation and its relationship with ROCK activity during T. cruzi infection.

Methods

PMA-induced, wild-type, GFP-, CA-ROCK1- and CA-ROCK2-expressing U937 macrophages were incubated with atorvastatin, or the inhibitors Y-27632, JSH-23, TAK-242, or C3 exoenzyme incubated with or without T. cruzi trypomastigotes for 30 min to evaluate the activity of ROCK and the M1 and M2 cytokine expression and secretion profiling. Also, ROCK activity was determined in T. cruzi-infected, BALB/c mice hearts.

Results

In this study, we demonstrate for the first time in macrophages that incubation with T. cruzi leads to ROCK activation via the TLR4 pathway, which triggers NF-κB activation. Inhibition of ROCKs by Y-27632 prevents NF-κB activation and the expression and secretion of M1 markers, as does treatment with atorvastatin. Furthermore, we show that the effect of atorvastatin on the NF-kB pathway and cytokine secretion is mediated by ROCK. Finally, statin treatment decreased ROCK activation and expression, and the pro-inflammatory cytokine production, promoting anti-inflammatory cytokine expression in chronic chagasic mice hearts.

Conclusion

These results suggest that the statin modulation of the inflammatory response due to ROCK inhibition is a potential pharmacological strategy to prevent cardiac inflammation in CCC.

Evaluation of the usefulness of determining the level of selected inflammatory biomarkers and resistin concentration in perivascular adipose tissue and plasma for predicting postoperative atrial fibrillation in patients who underwent myocardial revascularisation

BACKGROUND

The development of coronary artery disease (CAD) is related to the impaired quantity and composition of inflammatory proteins found in plasma and tissue, such as interleukin 6 (IL-6), adipokines, and resistin. Therefore, the level of plasma resistin in patients with advanced CAD could be indicative of the condition of epicardial adipose tissue and thus have an impact on the frequency and severity of postoperative complications in the form of paroxysmal atrial fibrillation.

METHODS

The study included 108 patients who qualified for elective coronary artery bypass grafting (CABG) surgery from 2017 to 2020 and were categorized into two groups. The first group consisted of patients who developed atrial fibrillation in the postoperative period - the AF group, and the second group included patients who did not have arrhythmia - the non-AF group. The analysis incorporates the history, course of treatment, anthropometric characteristics of the test subjects, biochemical laboratory tests, and echocardiography. Perivascular adipose tissue (PVAT) sections were surgically harvested from the area of the left coronary trunk.

RESULTS

The resistin levels in the PVAT were significantly higher in the AF group than in the non-AF group (P = 0.000015). Similarly, plasma resistin levels increased significantly in the AF group compared to the non-AF group (P = 0.044). The values of other analyzed variables were not significantly different (analysis performed using the Mann-Whitney U test). Spearman's rank-order correlation technique found a correlation between resistin in PVAT and plasma (r = 0.5933; P < 0.0001) in the whole study group, as well as in the AF group (r = 0.4782; P = 0.021) and the non-AF group (r = 0.4938; P < 0.0001). A correlation arose between the level of resistin in PVAT and the level of hsCRP (r = 0.3463; P = 0.005) in the whole study group and the non-AF group (r = 0.4448; P = 0.0011); however, no such correlation appeared in the AF group (r = 0.3076; P = 0.306).

CONCLUSIONS

Elevated levels of plasma resistin, which reflect PVAT resistin levels in patients qualified for myocardial revascularisation, may be associated with postoperative atrial fibrillation complications.

Vascular smooth muscle cells in intimal hyperplasia, an update

Arterial occlusive disease is the leading cause of death in Western countries. Core contemporary therapies for this disease include angioplasties, stents, endarterectomies and bypass surgery. However, these treatments suffer from high failure rates due to re-occlusive vascular wall adaptations and restenosis. Restenosis following vascular surgery is largely due to intimal hyperplasia. Intimal hyperplasia develops in response to vessel injury, leading to inflammation, vascular smooth muscle cells dedifferentiation, migration, proliferation and secretion of extra-cellular matrix into the vessel's innermost layer or intima. In this review, we describe the current state of knowledge on the origin and mechanisms underlying the dysregulated proliferation of vascular smooth muscle cells in intimal hyperplasia, and we present the new avenues of research targeting VSMC phenotype and proliferation.

Rho-Kinase inhibition decreases focal cerebral ischemia-induced glial activation in rats

Background

Rho-kinase inhibition in a rat middle cerebral artery occlusion (MCAO) model is reported to improve neurological functions and decrease infarction size.

Objective

The objective of this study is to investigate the underlying mechanisms of such improvement by evaluating the effects of Rho-kinase inhibition on astrocytes and microglial accumulation and activation in this condition.

Methods

Adult male Sprague-Dawley (SD) rats were used to generate the MCAO model, which received an I.P injection of a chemical Rho-kinase inhibitor (Fasudil- 5 mg/kg/day) or vehicle (PBS) for 2 and 4 days.

Results

Fasudil treatment significantly decreased the stroke volumes and water content in the lesion areas, as revealed by MRI. Immunostaining and Western blotting results demonstrated that Fasudil significantly decreased the levels of Aquaporin-4, a water channel protein. The number of GFAP⁺ astrocytes and Iba-1⁺ macrophage/microglia was decreased in the lesion areas. Proinflammatory transcription factor NF-κB protein levels were decreased in the Fasudil group 2 days after MCAO. Also, proinflammatory mediators including TNF-α, IL-1β, and iNOS levels were decreased. In vitro migration study using a human microglial cell line (HMO6) confirmed the inhibitory effects of Fasudil on the process. Fasudil also decreased combined IL-1β and IFNγ-induced NF-κB nuclear translocation in HMO6. Moreover, Fasudil transiently decreased combined IL-1β and IFNγ-induced iNOS, TNFα, and IL-1β mRNA levels in HMO6.

Conclusion

Our study demonstrates the inhibitory effects of Rho-kinase on NF-κB-mediated glial activation and cerebral edema, which might be a promising therapeutic target in acute cerebral ischemia conditions.

Pathogenic gene expression of epicardial adipose tissue in patients with coronary artery disease

Background & objectives:

Coronary artery disease (CAD), a leading cause of mortality and morbidity worldwide has multifactorial origin. Epicardial adipose tissue (EAT) has complex mechanical and thermogenic functions and paracrine actions via various cytokines released by it, which can have both pro- and anti-inflammatory actions on myocardium and adjacent coronaries. The alteration of EAT gene expression in CAD is speculated, but poorly understood. This study was undertaken to find out the difference in gene expression of epicardial fat in CAD and non-CAD patients.

Methods:

Twenty seven patients undergoing coronary artery bypass graft (CABG) and 16 controls (non-CAD patients undergoing valvular heart surgeries) were included in the study and their EAT samples were obtained. Gene expressions of uncoupling protein-1, monocyte chemoattractant protein-1 (MCP-1), adiponectin, adenosine A1 receptor (ADORA-1), vascular cell adhesion molecule-1 (VCAM-1) and tumour necrosis factor-alpha (TNF-α) were studied by real-time reverse transcription-polymerase chain reaction. Glucose, insulin, lipid profile, high-sensitivity C-reactive protein, homocysteine, vitamin D, TNF-α and leptin levels were estimated in fasting blood samples and analyzed.

Results:

Leptin levels were significantly higher in CABG group as compared to controls (P<0.05), whereas other metabolic parameters were not significantly different between the two groups. MCP-1, VCAM-1 and TNF-α were upregulated in the CABG group as compared to controls. Further, multivariate analysis showed significantly reduced adjusted odds ratio for MCP-1 [0.27; 95% confidence interval: 0.08-0.91] in the CABG group as compared to controls (P<0.05).

Interpretation & conclusions:

Our findings showed an alteration in EAT gene expression in CAD patients with significant upregulation of MCP-1. Further studies with a large sample need to be done to confirm these findings.

Relation between quantity and quality of peri-coronary epicardial adipose tissue and its underlying hemodynamically significant coronary stenosis

BACKGROUND

We aimed to investigate the association of lesion-specific epicardial adipose tissue (EAT) volume and density with the presence of myocardial ischemia.

METHODS

We enrolled 45 patients (55 lesions) with known or suspected coronary artery disease who underwent coronary computed tomography angiography (CTA) followed by invasive fractional flow reserve (FFR) assessment within 30 days. EAT volume (index) and density in patient-, vessel- and lesion-level were measured on CTA images. Lesion-specific ischemia was defined as a lesion with stenosis diameter > 90% or FFR ≤0.80. Multivariate analysis determined the independent association of EAT parameters with lesion-specific ischemia.

RESULTS

Mean age of the patients was 60 years, and 75% were male. Overall, 55.6% of patients had ischemic lesions and a mean FFR baseline value of 0.82 ± 0.10. Total EAT volume index was significantly higher in patients with functionally or anatomically significant stenosis. Specifically, peri-lesion EAT volume index, not the density, was positively correlated with lesion-specific ischemia independent of luminal stenosis and plaque characteristics (hazard ratio 1.56, 95% confidence interval 1.04-2.33, P = 0.032; per 0.1 ml/m² increase). Moreover, peri-lesion EAT volume was negatively correlated with lesion FFR values, whereas total EAT volume was positively correlated with fat accumulation and glucose metabolism. In addition, there was no association of EAT volume or density with myocardial ischemia in vessel-level analysis.

CONCLUSIONS

Lesion-specific EAT volume index, but not density, seems positively and independently associated with myocardial ischemia, while its incremental diagnostic value of lesion-specific ischemia should be further investigated.

Echocardiographic measurement of epicardial adipose tissue thickness in patients with microvascular angina

Introduction

Impaired coronary microcirculation, inflammation, and endothelial dysfunction were reported etiological factors for microvascular angina (MVA). Recently, increased epicardial adipose tissue (EAT) thickness has been associated with hypertension, metabolic syndrome, and coronary artery disease in general population. In this study, we aimed to evaluate the EAT thickness in patients with MVA.

Methods

This study enrolled 200 patients (83 males; mean age: 55.4 ± 8.2 years) who have been diagnosed with MVA and 200 controls (89 males; mean age: 54.4 ± 8.5 years). All patients underwent transthoracic echocardiography, and EAT thickness was measured from a parasternal long-axis view as the hypoechoic space on the right ventricular free wall.

Results

The mean EAT thickness was significantly higher in MVA patients than the controls (5.5 ± 1.1 vs. 4.9 ± 0.7 mm; p < 0.001). Multiple logistic regression analysis showed that increased EAT thickness was an independent predictor of MVA (OR = 1.183, 95% CI = 1.063-1.489; p = 0.023). In receiver operating characteristic curve analyses, EAT thickness above 5.3 mm predicted MVA with a sentivity of 68% and a specificity of 63% (AUC = 0.711, 95% CI = 0.659-0.762; p < 0.001).

Conclusions

The EAT thickness was observed significantly higher in MVA patients as compared to controls. Increased EAT thickness may be associated with mechanisms that play a major role in the pathogenesis of MVA.

Presence of fragmented QRS is associated with increased epicardial adipose tissue thickness in hypertensive patients

BACKGROUND

Epicardial adipose tissue (EAT) is a cardiometabolic risk factor, and its possible relationship with hypertension has been reported previously. Fragmented QRS (fQRS) detected on electrocardiography (ECG) has been demonstrated to be a marker of myocardial fibrosis. In this study, we aimed to investigate the relationship between the thickness of EAT, and presence of fQRS in hypertensive patients.

METHODS

Consecutive patients who were diagnosed with hypertension were included in the study. ECG and transthoracic echocardiography (TTE) were performed to all patients. fQRS was defined as additional R' wave or notching/splitting of S wave in two contiguous ECG leads. Thickness of EAT was measured by TTE.

RESULTS

This study enrolled 69 hypertensive patients with fQRS on ECG and 45 hypertensive patients without fQRS as the control group. Age (P = .869), and gender distribution (P = .751) were similar in both groups. Left atrial diameter (P = .012), interventricular septal thickness (P < .001), posterior wall thickness (P < .001), left ventricular ejection fraction (P = .009), left ventricular mass (P = .006), left ventricular mass ındex (P = .014), left ventricular hypertrophy (P = .003), and EAT thickness (P < .001) were found to be significantly increased in patients with fQRS. In multivariate analysis, among these variables only EAT was observed to be an independent predictor of fQRS (odds ratio:3.306 [95% confidence interval, 0.030-0.118], P = .001).

CONCLUSION

A significant association exists between the presence of fQRS and EAT thickness in hypertensive patients. The presence of fQRS, just as EAT thickness, may be used as a cardiometabolic risk factor in hypertensive patients.

ROCK2 Regulates Monocyte Migration and Cell to Cell Adhesion in Vascular Endothelial Cells

The small GTPase Rho and its downstream effector, Rho-kinase (ROCK), regulate various cellular functions, including organization of the actin cytoskeleton, cell adhesion and migration. A pro-inflammatory lipid mediator, lysophosphatidic acid (LPA), is a potent activator of the Rho/ROCK signalling pathway and has been shown to induce the expression of chemokines and cell adhesion molecules (CAMs). In the present study, we aimed to elucidate the precise mechanism by which ROCK regulates LPA-induced expressions and functions of chemokines and CAMs. We observed that ROCK blockade reduced LPA-induced phosphorylation of IκBα and inhibited NF-κB RelA/p65 phosphorylation, leading to attenuation of RelA/p65 nuclear translocation. Furthermore, small interfering RNA-mediated ROCK isoform knockdown experiments revealed that LPA induces the expression of monocyte chemoattractant protein-1 (MCP-1) and E-selectin via ROCK2 in human aortic endothelial cells (HAECs). Importantly, we found that ROCK2 but not ROCK1 controls LPA-induced monocytic migration and monocyte adhesion toward endothelial cells. These findings demonstrate that ROCK2 is a key regulator of endothelial inflammation. We conclude that targeting endothelial ROCK2 is potentially effective in attenuation of atherosclerosis.

Fimasartan for Remodeling after Myocardial Infarction

An angiotensin receptor blocker (ARB) mitigates cardiac remodeling after myocardial infarction (MI). Here, we investigated the effect of fimasartan, a new ARB, on cardiac remodeling after MI. Sprague–Dawley rats were assigned into 3 groups: surgery only (sham group, n = 7), MI without (MI-only group, n = 13), and MI with fimasartan treatment (MI + Fima group, n = 16). MI was induced by the permanent ligation of the left anterior descending artery. Treatment with fimasartan (10 mg/kg) was initiated 24 h after MI and continued for 7 weeks. Rats in the MI + Fima group had a higher mean ejection fraction (66.3 ± 12.5% vs. 51.3 ± 14.8%, P = 0.002) and lower left ventricular end-diastolic diameter (9.14 ± 1.11 mm vs. 9.91 ± 1.43 mm, P = 0.045) than those in the MI-only group at 7 weeks after MI. The infarct size was lower in the MI + Fima than in the MI group (P < 0.05). A microarray analysis revealed that the expression of genes related to the lipid metabolism and mitochondrial membrane ion transporters were upregulated, and those involved in fibrosis and inflammation were downregulated by fimasartan. Fimasartan attenuates cardiac remodeling and dysfunction in rats after MI and may prevent the progression to heart failure after MI.

Epicardial Adipose Tissue and Renal Disease

Epicardial adipose tissue (EAT) is derived from splanchnic mesoderm, localized anatomically between the myocardium and pericardial visceral layer, and surrounds the coronary arteries. Being a metabolically active organ, EAT secretes numerous cytokines, which moderate cardiovascular morphology and function. Through its paracrine and vasocrine secretions, EAT may play a prominent role in modulating cardiac function. EAT protects the heart in normal physiological conditions by secreting a variety of adipokines with anti-atherosclerotic properties, and in contrast, secretes inflammatory molecules in pathologic conditions that may play a dynamic role in the pathogenesis of cardiovascular diseases by promoting atherosclerosis. Considerable research has been focused on comparing the anatomical and biochemical features of EAT in healthy people, and a variety of disease conditions such as cardiovascular diseases and renal diseases. The global cardiovascular morbidity and mortality in renal disease are high, and there is a paucity of concrete evidence and societal guidelines to detect early cardiovascular disease (CVD) in this group of patients. Here we performed a clinical review on the existing evidence and knowledge on EAT in patients with renal disease, to evaluate its application as a reliable, early, noninvasive biomarker and indicator for CVD, and to assess its significance in cardiovascular risk stratification.

The Association of Epicardial Adipose Tissue and the Metabolic Syndrome in Community Participants in South Africa

Background:

We sought to determine the association of echocardiographically derived epicardial adipose tissue (EAT) thickness, which is a component of visceral adipose tissue, with the metabolic syndrome (MetS) in a cohort of randomly selected community participants.

Methods:

South African-Asian Indians aged 15–64 years were recruited over a 2-year period after informed consent was obtained. All participants who had complete measurements done for biochemistry and echocardiography (using established criteria), were dichotomized into the MetS or non-MetS groups defined according to the harmonized criteria.

Results:

Of the 953 (232 men and 721 women) participants recruited, 47.1% (448) were classified with the MetS. These participants had larger waist circumference and body mass index (P < 0.001), with larger LA volumes and diameter, thicker ventricular walls, higher left ventricular mass, relative wall thickness, and EAT (P < 0.001). There was a corresponding increase in EAT thickness with increasing number of MetS risk factors at the transition from 0 MetS factors to 1 (95% confidence interval [CI] −0.8; −0.2) and from 2 to 3 MetS factors (95% CI −0.9; −0.4). The AUC of the receiver operator curve was highest for triglycerides (0.845), followed by fasting plasma glucose (0.795) and then EAT (0.789). An EAT value of <3.6 mm predicted the presence of the MetS with a 78% sensitivity and 70% specificity. Using backward stepwise logistic regression, the most significant independent determinants of the MetS after adjusting for age, gender, and type 2 diabetes mellitus, was fasting plasma glucose (odds ratio [OR] = 1.2), triglycerides (OR = 7.1), and EAT (OR = 2.3).

Conclusion:

Although EAT is associated with the MetS, and can identify individuals at increased cardiometabolic risk, it has a limited additional role compared to current risk markers.

The Rho-associated kinase inhibitors Y27632 and fasudil promote microglial migration in the spinal cord via the ERK signaling pathway

Rho-associated kinase (ROCK) is a key regulatory protein involved in inflammatory secretion in microglia in the central nervous system. Our previous studies showed that ROCK inhibition enhances phagocytic activity in microglia through the extracellular signal-regulated kinase (ERK) signaling pathway, but its effect on microglial migration was unknown. Therefore, in this study, we investigated the effects of the ROCK inhibitors Y27632 and fasudil on the migratory activity of primary cultured microglia isolated from the spinal cord, and we examined the underlying mechanisms. The microglia were treated with Y27632, fasudil and/or the ERK inhibitor U0126. Cellular morphology was observed by immunofluorescence. Transwell chambers were used to assess cell migration. ERK levels were measured by in-cell western blot assay. Y27632 and fasudil increased microglial migration, and the microglia were irregularly shaped and had many small processes. These inhibitors also upregulated the levels of phosphorylated ERK protein. The ERK inhibitor U0126 suppressed these effects of Y27632 and fasudil. These findings suggest that the ROCK inhibitors Y27632 and fasudil promote microglial migration in the spinal cord through the ERK signaling pathway.

Gene expression profiling reveals heterogeneity of perivascular adipose tissues surrounding coronary and internal thoracic arteries

The internal thoracic artery (ITA) that differs from coronary artery (CA), rarely develops atherosclerosis. Understanding the mechanism underlying such a difference will help to pave a new way to the prevention and treatment of the disease. We hypothesize herein that the difference in susceptibility to atherosclerosis between CA and ITA is attributable to the heterogeneity of perivascular adipose tissues (PVATs) surrounding these two kinds of arteries, i.e. PVAT-CA and PVAT-ITA. We isolated PVAT from eight patients of coronary heart disease (CHD) and four non-CHD patients. Gene expression patterns were analyzed by using Agilent whole gene expression profile chips. By comparison between PVAT-CA and PVAT-ITA, we identified 2053 differentially expressed genes, of which 1042 were up-regulated and 1011 were down-regulated, respectively, in CHD group. KEGG pathway and gene ontology (GO) analysis revealed that those differentially expressed genes related to inflammation, lipid metabolism and myocardial processes were particularly noted in the CHD group, but not in non-CHD. Several selected genes, including interleukin-1β (IL-1β), interleukin-6 (IL-6), Toll-like receptor 2 (TLR2), Toll-interleukin 1 receptor domain containing adaptor protein (TIRAP), serum amyloid A2 (SAA2), and Leptin were validated by real-time PCR analysis. The results showed that the expression levels of IL-1β, IL-6, and Leptin were significantly higher in PVAT-CA than in PVAT-ITA (P = 0.016, 0.021, and 0.018) in CHD patients. Levels of TLR2, TIRAP, and SAA2 expression were also higher in PVAT-CA, however no significant difference was observed (P = 0.054, 0.092, and 0.058). In conclusion, our findings demonstrate differential gene expression patterns between PVAT-CA and PVAT-ITA, revealing a high heterogeneity in PVAT. Particularly, those genes related to inflammation, lipid metabolism and myocardial processes are differentially expressed in PVAT-CA and PVAT-ITA in CHD patients, suggesting an important role of PVAT in the development of coronary atherosclerosis.

Role of PVAT in coronary atherosclerosis and vein graft patency: friend or foe?

Perivascular adipose tissue (PVAT) releases numerous factors and adipokines with paracrine effects on both vascular structure and function. These effects are variable as they depend on regional differences in PVAT among blood vessels and vary with changes in adiposity. There is considerable evidence demonstrating an association between coronary PVAT and the development and progression of coronary artery disease, which is associated with inflammation, oxidative stress, angiogenesis, vascular remodelling and blood clotting. However, PVAT also has a protective role in vascular grafts, especially the no-touch saphenous vein, in patients undergoing coronary artery bypass. This beneficial influence of PVAT involves factors such as adipocyte-derived relaxing factor, nitric oxide (NO), leptin, adiponectin, prostanoids, hydrogen sulphide and neurotransmitters, as well as mechanical protection. This article aims to highlight and compare the dual role of PVAT in the development and progression of coronary atherosclerosis, as well as in increased graft patency. Different deleterious and protective mechanisms of PVAT are also discussed and the inside-outside signalling paradigm of atherosclerosis development re-evaluated. The bidirectional communication between the arterial and venous wall and their surrounding PVAT, where signals originating from the vascular wall or lumen can affect PVAT phenotype, has been shown to be very complex. Moreover, signals from PVAT also influence the structure and function of the vascular wall in a paracrine manner.

LINKED ARTICLES

This article is part of a themed section on Molecular Mechanisms Regulating Perivascular Adipose Tissue - Potential Pharmacological Targets? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.20/issuetoc.

RhoA/Rho-Kinase in the Cardiovascular System

Twenty years ago, Rho-kinase was identified as an important downstream effector of the small GTP-binding protein, RhoA. Thereafter, a series of studies demonstrated the important roles of Rho-kinase in the cardiovascular system. The RhoA/Rho-kinase pathway is now widely known to play important roles in many cellular functions, including contraction, motility, proliferation, and apoptosis, and its excessive activity induces oxidative stress and promotes the development of cardiovascular diseases. Furthermore, the important role of Rho-kinase has been demonstrated in the pathogenesis of vasospasm, arteriosclerosis, ischemia/reperfusion injury, hypertension, pulmonary hypertension, and heart failure. Cyclophilin A is secreted by vascular smooth muscle cells and inflammatory cells and activated platelets in a Rho-kinase-dependent manner, playing important roles in a wide range of cardiovascular diseases. Thus, the RhoA/Rho-kinase pathway plays crucial roles under both physiological and pathological conditions and is an important therapeutic target in cardiovascular medicine. Recently, functional differences between ROCK1 and ROCK2 have been reported in vitro. ROCK1 is specifically cleaved by caspase-3, whereas granzyme B cleaves ROCK2. However, limited information is available on the functional differences and interactions between ROCK1 and ROCK2 in the cardiovascular system in vivo. Herein, we will review the recent advances about the importance of RhoA/Rho-kinase in the cardiovascular system.

Vitamin D Deficiency Accelerates Coronary Artery Disease Progression in Swine

OBJECTIVE

The role of vitamin D deficiency in coronary artery disease (CAD) progression is uncertain. Chronic inflammation in epicardial adipose tissue (EAT) has been implicated in the pathogenesis of CAD. However, the molecular mechanism underlying vitamin D deficiency-enhanced inflammation in the EAT of diseased coronary arteries remains unknown. We examined a mechanistic link between 1,25-dihydroxyvitamin D-mediated suppression of nuclear factor-κB (NF-κB) transporter, karyopherin α4 (KPNA4) expression and NF-κB activation in preadipocytes. Furthermore, we determined whether vitamin D deficiency accelerates CAD progression by increasing KPNA4 and nuclear NF-κB levels in EAT.

APPROACH AND RESULTS

Nuclear protein levels were detected by immunofluorescence and Western blot. Exogenous KPNA4 was transported into cells by a transfection approach and constituted lentiviral vector. Swine were administered vitamin D-deficient or vitamin D-sufficient hypercholesterolemic diet. After 1 year, the histopathology of coronary arteries and nuclear protein expression of EAT were assessed. 1,25-dihydroxyvitamin D inhibited NF-κB activation and reduced KPNA4 levels through increased vitamin D receptor expression. Exogenous KPNA4 rescued 1,25-dihydroxyvitamin D-dependent suppression of NF-κB nuclear translocation and activation. Vitamin D deficiency caused extensive CAD progression and advanced atherosclerotic plaques, which are linked to increased KPNA4 and nuclear NF-κB levels in the EAT.

CONCLUSIONS

1,25-dihydroxyvitamin D attenuates NF-κB activation by targeting KPNA4. Vitamin D deficiency accelerates CAD progression at least, in part, through enhanced chronic inflammation of EAT by upregulation of KPNA4, which enhances NF-κB activation. These novel findings provide mechanistic evidence that vitamin D supplementation could be beneficial for the prevention and treatment of CAD.

Rho-Associated Kinase Inhibitors Promote Microglial Uptake Via the ERK Signaling Pathway

Microglia are immunocompetent cells in the central nervous system that take up tissue debris and pathogens. Rho-associated kinase (ROCK) has been identified as an important regulator of uptake, proliferation, secretion, and differentiation in a number of cell types. Although ROCK plays critical roles in the microglial secretion of inflammatory factors, migration, and morphology, its effects on microglial uptake activity have not been well characterized. In the present study, we found that treatment of BV2 microglia and primary microglia with the ROCK inhibitors Y27632 and fasudil increased uptake activity and was associated with morphological changes. Furthermore, western blots showed that this increase in uptake activity was mediated through the extracellular-signal-regulated kinase (ERK) signaling cascade, indicating the importance of ROCK in regulating microglial uptake activity.

Epicardial fat thickness: A surrogate marker of coronary artery disease - Assessment by echocardiography

OBJECTIVE

Epicardial fat is considered as indicator of cardiovascular risk. Several studies have tested the association between epicardial fat thickness (EFT) and coronary artery disease. The aim of our study is to test the hypothesis that echocardiographic EFT is a marker of coronary artery disease.

METHODS

One hundred and ten patients (70 males and 40 females with mean age of 51.5±10.6 and 52.6±9.6, respectively) admitted for coronary angiogram underwent assessment of epicardial fat thickness by echocardiography. Routine clinical examination, evaluation of risk factor profile, and anthropometric variables were also done. Epicardial fat thickness was measured on the free wall of right ventricle in parasternal long- and short-axis views at end-systole for 3 cardiac cycles.

RESULTS

Mean epicardial fat thickness in angiographically normal patients and acute coronary syndromes were 4.4±1.2 and 6.9±1.9, respectively. Epicardial fat thickness in males and females were not statistically different. Burden of coronary arterial lesions denoted by Gensini score shows linear association with epicardial fat thickness and the severity of the coronary disease.

CONCLUSION

Epicardial fat is independently and linearly associated with CAD and its severity.

Cyclophilin A in cardiovascular homeostasis and diseases

Vascular homeostasis is regulated by complex interactions between many vascular cell components, including endothelial cells, vascular smooth muscle cells (VSMCs), adventitial inflammatory cells, and autonomic nervous system. The balance between oxidant and antioxidant systems determines intracellular redox status, and their imbalance can cause oxidative stress. Excessive oxidative stress is one of the important stimuli that induce cellular damage and dysregulation of vascular cell components, leading to vascular diseases through multiple pathways. Cyclophilin A (CyPA) is one of the causative proteins that mediate oxidative stress-induced cardiovascular dysfunction. CyPA was initially discovered as the intracellular receptor of the immunosuppressive drug cyclosporine 30 years ago. However, recent studies have established that CyPA is secreted from vascular cell components, such as endothelial cells and VSMCs. Extracellular CyPA augments the development of cardiovascular diseases. CyPA secretion is regulated by Rho-kinase, which contributes to the pathogenesis of vasospasm, arteriosclerosis, ischemia/reperfusion injury, hypertension, pulmonary hypertension, and heart failure. We recently reported that plasma CyPA levels are significantly higher in patients with coronary artery disease, which is associated with increased numbers of stenotic coronary arteries and the need for coronary intervention in such patients. Furthermore, we showed that the vascular erythropoietin (Epo)/Epo receptor system plays an important role in production of nitric oxide and maintenance of vascular redox state and homeostasis, with a potential mechanistic link to the Rho-kinase-CyPA pathway. In this article, I review the data on the protective role of the vascular Epo/Epo receptor system and discuss the roles of the CyPA/Rho-kinase system in cardiovascular diseases.

Fasudil, a Rho‑kinase inhibitor, prevents intima‑media thickening in a partially ligated carotid artery mouse model: Effects of fasudil in flow‑induced vascular remodeling

Vascular remodeling in response to hemodynamic alterations is a physiological process that requires coordinated signaling between endothelial, inflammatory and vascular smooth muscle cells (VSMCs). Extensive experimental and clinical studies have indicated the critical role of the Ras homolog gene family, member A/Rho‑associated kinase (ROCK) signaling pathway in the pathogenesis of cardiovascular disease, where ROCK activation has been demonstrated to promote inflammation and remodeling through inducing the expression of proinflammatory cytokines and adhesion molecules in endothelial cells and VSMCs. However, the role of ROCK in flow‑induced vascular remodeling has not been fully defined. The current study aimed to investigate the effect of the ROCK signaling pathway in flow‑induced vascular remodeling by comparing the responses to partial carotid artery ligation in mice treated with fasudil (a ROCK inhibitor) and untreated mice. Intima‑media thickness and neointima formation were evaluated by morphology. VSMC proliferation and inflammation of the vessel wall were assessed by immunohistochemistry. In addition, the expression levels of ROCK and the downstream effectors of ROCK, myosin light chain (MLC) and phosphorylated‑MLC (p‑MLC), were quantified by western blot analysis. Following a reduction in blood flow, ROCK1 and p‑MLC expression increased in the untreated left common carotid arteries (LCA). Fasudil‑treated mice developed a significantly smaller intima‑media thickness compared with the untreated mice. Quantitative immunohistochemistry of the fasudil‑treated LCA indicated that there was a reduction in proliferation when compared with untreated vessels. There were fewer CD45+ cells observed in the fasudil‑treated LCA compared with the untreated LCA. In conclusion, the expression of ROCK was enhanced in flow‑induced carotid artery remodeling and ROCK inhibition as a result of fasudil treatment may attenuate flow‑induced carotid artery remodeling.

Pericoronary adipose tissue: a novel therapeutic target in obesity-related coronary atherosclerosis

Inflammation plays a crucial role in the development and destabilization of atherosclerotic plaques in coronary vessels. Adipose tissue is considered to act in paracrine manner, which modulates a number of physiological and pathophysiological processes. Perivascular adipose tissue has developed specific properties that distinguish it from the fat in other locations. Interestingly, its activity depends on several metabolic conditions associated with insulin resistance and weight gain. Particularly in obesity perivascular fat seems to change its character from a protective to a detrimental one. The present review analyzes literature in terms of the pathophysiology of atherosclerosis, with particular emphasis on inflammatory processes. Additionally, the authors summarize data about confirmed paracrine activity of visceral adipose tissue and especially about pericoronary fat influence on the vascular wall. The contribution of adiponectin, leptin and resistin is addressed. Experimental and clinical data supporting the thesis of outside-to-inside signaling in the pericoronary milieu are further outlined. Clinical implications of epicardial and pericoronary adipose tissue activity are also evaluated. The role of pericoronary adipose tissue in obesity-related atherosclerosis is highlighted. In conclusion, the authors discuss potential therapeutical implications of these novel phenomena, including adipokine imbalance in pericoronary adipose tissue in the setting of obesity, the influence of lifestyle and diet modification, pharmaceutical interventions and the growing role of microRNAs in adipogenesis, insulin resistance and obesity. Key teaching points: • adipose tissue as a source of inflammatory mediators • changes in the vascular wall as a result of outside-to-inside signaling • anatomy, physiology, and clinical implications of epicardial and pericoronary adipose tissue activity • adipokines and their role in obesity-related atherosclerosis • therapeutic perspectives and future directions.

Correlation between pericardial, mediastinal, and intrathoracic fat volumes with the presence and severity of coronary artery disease, metabolic syndrome, and cardiac risk factors

AIMS

To investigate the association of pericardial, mediastinal, and intrathoracic fat volumes with the presence and severity of coronary artery disease (CAD), metabolic syndrome (MS), and cardiac risk factors (CRFs).

METHODS AND RESULTS

Two hundred and sixteen consecutive patients who underwent cardiac magnetic resonance (CMR) imaging and had a coronary angiogram within 12 months of the CMR were studied. Fat volume was measured by drawing region of interest curves, from short-axis cine views from base to apex and from a four-chamber cine view. Pericardial fat, mediastinal fat, intrathoracic fat (addition of pericardial and mediastinal fat volumes), and fat ratio (pericardial fat/mediastinal fat) were analysed for their association with the presence and severity of CAD (determined based on the Duke CAD Jeopardy Score), MS, CRFs, and death or myocardial infarction on follow-up. Pericardial fat volume was significantly greater in patients with CAD when compared with those without CAD [38.3 ± 25.1 vs. 31.9 ± 21.4 cm(3) (P = 0.04)]. A correlation between the severity of CAD and fat volume was found for pericardial fat (β = 1, P < 0.01), mediastinal fat (β = 1, P = 0.03), intrathoracic fat (β = 2, P = 0.01), and fat ratio (β = 0.005, P = 0.01). These correlations persisted for all four thoracic fat measurements even after performing a stepwise linear regression analysis for relevant risk factors. Patients with MS had significantly greater mediastinal and intrathoracic fat volumes when compared with those without MS [126 ± 33.5 vs. 106 ± 30.1 cm(3) (P < 0.01) and 165 ± 54.9 vs. 140 ± 52 cm(3) (P < 0.01), respectively]. However, there was no significant difference in pericardial fat, mediastinal fat, intrathoracic fat, or fat ratio between patients with or without myocardial infarction during the follow-up [33.6 ± 22.1 vs. 35.7 ± 23.8 cm(3) (P = 0.67); 115 ± 26.2 vs. 114 ± 33.8 cm(3) (P = 0.84); 149 ± 44.7 vs. 150 ± 55.7 cm(3) (P = 0.95); and 0.27 ± 0.15 vs. 0.28 ± 0.14 (P = 0.70), respectively]. There was no significant difference in pericardial fat, mediastinal fat, intrathoracic fat, or fat ratio between patients who were alive compared with those who died during follow-up [36.6 ± 26.6 vs. 35.3 ± 23.2 cm(3) (P = 0.76); 114 ± 40.2 vs. 114 ± 31.4 cm(3) (P = 0.95); 150 ± 64.7 vs. 149 ± 52.5 cm(3) (P = 0.92); and 0.29 ± 0.15 vs. 0.28 ± 0.14 (P = 0.85), respectively].

CONCLUSION

Our study confirms an association between pericardial fat volume with the presence and severity of CAD. Furthermore, an association between mediastinal and intrathoracic fat volumes with MS was found.

Rho-kinase as a therapeutic target in vascular diseases: striking nitric oxide signaling

Rho GTPases are a globular, monomeric group of small signaling G-protein molecules. Rho-associated protein kinase/Rho-kinase (ROCK) is a downstream effector protein of the Rho GTPase. Rho-kinases are the potential therapeutic targets in the treatment of cardiovascular diseases. Here, we have primarily discussed the intriguing roles of ROCK in cardiovascular health in relation to nitric oxide signaling. Further, we highlighted the biphasic effects of Y-27632, a ROCK inhibitor under shear stress, which acts as an agonist of nitric oxide production in endothelial cells. The biphasic effects of this inhibitor raised the question of safety of the drug usage in treating cardiovascular diseases.

Correlation of echocardiographic epicardial fat thickness with severity of coronary artery disease in patients with acute myocardial infarction

The aim of this study was to test the hypotheses that epicardial adipose tissue (EAT) can be a marker of severe coronary artery disease in patients with acute myocardial infarction. Overall, 373 cases who underwent coronary angiography were classified into 2 groups by SYNTAX score: low-score and high-score group. EAT was measured by transthoracic echocardiography. Obtained data were compared using Pearson correlation analyses and univariate and multiple logistic regression analysis. The results showed that EAT in the high-score group was significantly greater than in the normal group (5.6 ± 1.1 vs. 4.1 ± 1.0 mm, P < 0.01). EAT had a positive correlation with SYNTAX score (r = 0.61, P < 0.01). Receiver operating characteristic (ROC) curve analyses showed that EAT could reliably discriminate patients with high SYNTAX score (≥ 33) [AUC: 0.86, 95% confidence interval (CI): 0.822-0.898, P < 0.01]. Multivariate regression analyses showed that EAT was an independent predictor for major in-hospital events. These data showed an association between EAT and SYNTAX score.

The relationship between epicardial adipose tissue and ST-segment resolution in patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

The relationship between epicardial adipose tissue (EAT) and coronary artery disease has been predominantly demonstrated in the last two decades. The aim of this study was to investigate the predictive value of EAT thickness on ST-segment resolution that reflects myocardial reperfusion in patients undergoing primary percutaneous coronary intervention (pPCI) for acute ST-segment elevation myocardial infarction (STEMI). The present study prospectively included 114 consecutive patients (mean age 54 ± 10 years, range 35-83, 15 women) with first acute STEMI who underwent successful pPCI. ST-segment resolution (ΔSTR) <70 % was accepted as ECG sign of no-reflow phenomenon. The EAT thickness was measured by two-dimensional echocardiography. EAT thickness was increased in patients with no-reflow (3.9 ± 1.7 vs. 5.4 ± 2, p = 0.001). EAT thickness was also found to be inversely correlated with ΔSTR (r = -0.414, p = 0.001). Multivariate logistic regression analysis demonstrated that EAT thickness independently predicted no-reflow (OR 1.43, 95 % CI 1.13-1.82, p = 0.003). Receiver operating characteristic curve analysis demonstrated good diagnostic accuracy for EAT thickness in predicting no-reflow [area under curve (AUC) = 0.72, 95 % CI 0.63-0.82, p < 0.001]. In conclusion, increased EAT thickness may play an important role in the prediction of no-reflow in STEMI treated with pPCI.

Inhibition of rho-kinase by fasudil suppresses formation and progression of experimental abdominal aortic aneurysms

Objective

Accumulating evidence suggests that inflammatory cell infiltration is crucial pathogenesis during the initiation and progression of abdominal aortic aneurysm (AAA). Given Rho-kinase (ROCK), an important kinase control the actin cytoskeleton, regulates the inflammatory cell infiltration, thus, we investigate the possibility and mechanism of preventing experimental AAA progression via targeting ROCK in mice porcine pancreatic elastase (PPE) model.

Methods and Results

AAA was created in 10-week-old male C57BL/6 mice by transient intraluminal porcine pancreatic elastase infusion into the infrarenal aorta. The mRNA level of RhoA, RhoC, ROCK1 and ROCK2 were elevated in aneurismal aorta. Next, PPE infusion mice were orally administrated with vehicle or ROCK inhibitor (Fasudil at dose of 200 mg/kg/day) during the period of day 1 prior to PPE infusion to day 14 after PPE infusion. PPE infusion mice treated with Fasudil produced significantly smaller aneurysms as compare to PPE infusion mice treated with vehicle. AAAs developed in all vehicle-treated groups within 14 days, whereas AAAs developed in six mice (66%, 6/9) treated with Fasudil within 14 days. Furthermore, our semi-quantitative histological analysis revealed that blood vessels and macrophages were significantly reduced in Fasudil treated mice during the AAA progression. Finally, when mice with existing AAAs were treated with Fasudil, the enlargement was nearly completely suppressed.

Conclusion

Fasudil inhibits experimental AAA progression and stabilize existing aneurysms, through mechanisms likely related to impaired mural macrophage infiltration and angiogenesis. These findings suggest that ROCK inhibitor may hold substantial translational value for AAA diseases.

Echocardiographically measured epicardial fat predicts restenosis after coronary stenting

OBJECTIVE

Epicardial adipose tissue (EAT), deposited around subepicardial coronary vessels, may contribute directly to perivascular inflammation and smooth muscle cell proliferation. This study assessed the relationship between EAT and in-stent restenosis.

METHODS

Four hundred and seven patients had received successful coronary intervention. EAT thickness was measured by echocardiography. Angiographic follow-up was obtained between 6 months and 2 years. Restenosis was defined as target lesion revascularization (TLR). EAT thickness of patients was compared by TLR controlling for additional well-known predictors of restenosis. The TLR-free survival analysis according to EAT thickness was estimated using the Kaplan-Meier method and the differences between groups were assessed by the log-rank test.

RESULTS

Median EAT thickness was significantly increased in patients undergoing TLR compared with those without restenosis (3.7 vs. 3.0 mm, p = 0.001). EAT thickness was one of the independent factors associated with restenosis (Odds ratio = 1.19, 95% confidence interval = 1.01-1.33, p = 0.007). The TLR-free survival of patients with thick EAT was significantly worse than patients with thin EAT (log-rank p = 0.001).

CONCLUSIONS

EAT thickness is related with restenosis and may provide additional information for future restenosis.

Next-generation sequencing analysis of gene regulation in the rat model of retinopathy of prematurity

PURPOSE

The purpose of this study was to identify the genes, biochemical signaling pathways, and biological themes involved in the pathogenesis of retinopathy of prematurity (ROP).

METHODS

Next-generation sequencing (NGS) was performed on the RNA transcriptome of rats with the Penn et al. (Pediatr Res 36:724-731, 1994) oxygen-induced retinopathy model of ROP at the height of vascular abnormality, postnatal day (P) 19, and normalized to age-matched, room-air-reared littermate controls. Eight custom-developed pathways with potential relevance to known ROP sequelae were evaluated for significant regulation in ROP: The three major Wnt signaling pathways, canonical, planar cell polarity (PCP), and Wnt/Ca(2+); two signaling pathways mediated by the Rho GTPases RhoA and Cdc42, which are, respectively, thought to intersect with canonical and non-canonical Wnt signaling; nitric oxide signaling pathways mediated by two nitric oxide synthase (NOS) enzymes, neuronal (nNOS) and endothelial (eNOS); and the retinoic acid (RA) signaling pathway. Regulation of other biological pathways and themes was detected by gene ontology using the Kyoto Encyclopedia of Genes and Genomes and the NIH's Database for Annotation, Visualization, and Integrated Discovery's GO terms databases.

RESULTS

Canonical Wnt signaling was found to be regulated, but the non-canonical PCP and Wnt/Ca(2+) pathways were not. Nitric oxide signaling, as measured by the activation of nNOS and eNOS, was also regulated, as was RA signaling. Biological themes related to protein translation (ribosomes), neural signaling, inflammation and immunity, cell cycle, and cell death were (among others) highly regulated in ROP rats.

CONCLUSIONS

These several genes and pathways identified by NGS might provide novel targets for intervention in ROP.

Increased leukocyte Rho-kinase activity in a population with acute coronary syndrome

Accumulating evidence suggests that Rho-associated kinase (ROCK) may be important in the pathogenesis of atherosclerosis and coronary vasospasm. In the present study, we investigated whether ROCK activity is increased in acute coronary syndrome (ACS) patients. Twenty-one patients with ACS (12 males, mean age 58.0±8.0 years) and 20 control subjects (10 males, mean age 55.0±6.0 years) were enrolled. Blood samples were obtained and demographics were recorded. Peripheral leukocyte ROCK activity was determined by the ratio of phospho-myosin‑binding subunit (P-MBS) on myosin light-chain phosphatase to total MBS. Compared with the control subjects, ROCK activity was significantly increased in ACS patients (0.69±0.07 vs. 0.45±0.04, P<0.001). There was no apparent correlation between the lipid levels (total cholesterol and low-density lipoprotein) and ROCK activity (r=0.17, P>0.05; r=0.08, P>0.05; respectively). However, ROCK activity correlated with mean arterial pressure (r=0.58; P<0.01). ROCK activity is increased in ACS patients indicating that this may be a novel serological marker of ACS.

Correlation between endothelial dysfunction, Rho-associated protein kinase activity, C-reactive protein and obstructive sleep apnoea syndrome in male patients

OBJECTIVE

This study investigated the association between obstructive sleep apnoea syndrome (OSAS) and flow-mediated dilatation (FMD), Rho-associated protein kinase (ROCK) activity, and C-reactive protein (CRP) concentrations in male patients.

METHODS

Consecutive patients with symptoms suggestive of OSAS were recruited and divided into non-OSAS (n = 18) and OSAS (n = 32) groups. FMD was measured in the brachial artery; blood samples were taken to measure ROCK activity and CRP concentrations.

RESULTS

ROCK activity and CRP concentrations were significantly higher, and FMD was significantly lower, in the OSAS group than in the non-OSAS group. There was a correlation between ROCK activity and FMD. In stepwise multiple regression analyses, the proportion of sleep time spent with an oxygen saturation < 90% was a significant determinant of ROCK activity, while body mass index was the only significant determinant of CRP concentration. The oxygen desaturation index was a significant determinant of FMD.

CONCLUSIONS

OSAS increased ROCK activity and was a major determinant of endothelial dysfunction.

Relation of epicardial fat thickness and cardio-ankle vascular index to complexity of coronary artery disease in nondiabetic patients

OBJECTIVES

Arterial stiffness and epicardial fat thickness (EFT) are associated with coronary artery disease (CAD). The cardio-ankle vascular index (CAVI) is a novel marker of arterial stiffness. The SYNTAX score (SS) reflects the complexity of CAD. We aimed to evaluate the relation of EFT and CAVI with CAD complexity in nondiabetic patients.

METHOD

We enrolled 121 patients undergoing coronary angiography. In all patients, CAVI and EFT were determined. SS were calculated. The relationship between EFT, CAVI and SS was analyzed.

RESULTS

CAVI and EFT were significantly correlated with SS (r = 0.537, p < 0.001, and r = 0.629, p < 0.001, respectively) and found to be independent predictors of intermediate-high SS. For the prediction of intermediate-high SS, receiver-operating characteristic curve analysis revealed a cutoff value of 5 mm for EFT (area under the curve, AUC = 0.851, 95% confidence interval, CI, 0.775-0.910) with a specificity of 92.2% and a sensitivity of 77.4% and 8.6 for CAVI (AUC = 0.877, 95% CI 0.805-0.929) with a specificity of 68.9% and a sensitivity of 93.5%.

CONCLUSION

CAD complexity is associated with adverse cardiovascular events. It can be predicted noninvasively with EFT and CAVI in nondiabetic patients with suspected CAD. Thus, patients at high risk for cardiovascular events may be detected early and managed with appropriate treatment strategies.

[Epicardial adipose tissue: more than a simple fat deposit?]

Obesity increases the risk of development of atherosclerosis. However, this risk significantly depends on adipose tissue distribution in the body and ectopic accumulation of visceral adipose tissue (VAT). Recent evidence suggests that each visceral fat deposit is anatomically and functionally different. Due to proximity to the organ, each visceral fat deposit exerts a local modulation rather than a systemic effect. Because of its unique location and biomolecular properties, a "non-traditional" fat depot - the epicardial adipose tissue - has been considered to play a causative role in atherosclerosis. Epicardial adipose tissue may be measured with imaging techniques and is clinically related to left ventricular mass, coronary artery disease, and metabolic syndrome. Therefore, epicardial fat measurement may play a role in stratification of cardiometabolic risk and may serve as a therapeutic target.

Rho-associated coiled-coil-containing kinase 2 deficiency in bone marrow-derived cells leads to increased cholesterol efflux and decreased atherosclerosis

BACKGROUND

Macrophages play a central role in the development of atherosclerosis. However, the signaling pathways that regulate their function are not well understood. The Rho-associated coiled-coil-containing kinases (ROCK1 and ROCK2) are serine-threonine protein kinases that are involved in the regulation of the actin cytoskeleton. Recent studies suggest that ROCK1 in macrophages and bone marrow-derived cells mediates atherogenesis. However, a similar role for ROCK2 in the pathogenesis of atherosclerosis has not been determined.

METHODS AND RESULTS

The bone marrows from wild-type, ROCK2(+/-), and ROCK2(-/-) mice were transplanted into irradiated recipient low-density lipoprotein receptor(-/-) mice, and atherosclerosis was induced with a 16-week high-cholesterol diet. Compared with wild-type bone marrow-transplanted mice, ROCK2(+/-) bone marrow-transplanted and ROCK2(-/-) bone marrow-transplanted mice showed substantially less lipid accumulation in the aorta (8.46±1.42% and 9.80±2.34% versus 15.64±1.89%; P<0.01 for both) and decreased atherosclerotic lesions in the subaortic sinus (158.1±44.4 and 330.1±109.5×10(3)μm(2) versus 520.2±125.7×10(3)μm(2); P<0.01 for both). These findings correlated with decreased foam cell formation (2.27±0.57 versus 4.10±0.3; P<0.01) and increased cholesterol efflux (17.65±0.6 versus 9.75±0.8; P<0.05) in ROCK2-deficient mice that are mediated, in part, through the peroxisome proliferator-activated receptor-γ/liver X receptor/ATP-binding cassette transporter A1 pathway in macrophages.

CONCLUSIONS

ROCK2 contributes to atherosclerosis, in part, by inhibiting peroxisome proliferator-activated receptor-γ-mediated reverse cholesterol transport in macrophages, which contributes to foam cell formation. These findings suggest that inhibition of ROCK2 in macrophages may have therapeutic benefits in preventing the development of atherosclerosis.

The role of Rho/Rho-kinase pathway in the expression of ICAM-1 by linoleic acid in human aortic endothelial cells

Linoleic acid (LA), a dietary unsaturated fatty acid, has been known to increase the expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) through the activation of nuclear factor-kappa B. Rho/Rho-kinase (ROCK) pathway mediates various cellular functions related to cardiovascular disease and affects the expression of ICAM-1. However, the exact mechanism underlying this action has not been fully elucidated. In this study, we aimed to find out the role of Rho/ROCK pathway in LA-induced ICAM-1 expression in human aortic endothelial cells (HAECs). We found that LA increased ICAM-1 expression and phosphorylation of ROCK and MYPT-1, a distal signal of ROCK. Y-27632, a ROCK inhibitor, suppressed ICAM-1 expression and phosphorylation of MYPT-1 induced by LA. The effect of LA on the increased phosphorylation of MYPT1 and expression of ICAM-1 was abolished by knocking down RhoA and ROCK2 protein level expression using small interfering RNA. LA increased NF-κB DNA-binding activity, which was inhibited with pretreatment with Y-27632. This study suggests that Rho/ROCK pathway plays a role in LA-induced ICAM-1 expression, which is possibly mediated by NF-κB in HAECs.

RhoA localization with caveolin-1 regulates vascular contractions to serotonin

Vascular smooth muscle contraction occurs following an initial response to an increase in intracellular calcium concentration and a sustained response following increases in the sensitivity of contractile proteins to calcium (calcium sensitization). This latter process is regulated by the rhoA/rho kinase pathway and activated by serotonin. In multiple cell types, signaling molecules compartmentalize within caveolae to regulate their activation. We hypothesized that serotonin differentially compartmentalizes rhoA within caveolar versus noncaveolar lipid rafts to regulate sustained vascular contractions. To test this hypothesis, we measured aortic contractions in response to serotonin in wild-type (WT) and cav-1-deficient mice (cav-1 KO). RhoA-dependent contractions in response to serotonin were markedly augmented in arteries from cav-1 KO mice despite a modest reduction in rhoA expression compared with WT. We found that under basal conditions, rhoA in WT arteries was primarily localized within high-density sucrose gradient fractions but temporally shifted to low-density fractions in response to serotonin. In contrast, rhoA in cav-1 KO arteries was primarily in low-density fractions and shifted to high-density fractions in a similar timeframe as that seen in WT mice. We conclude that localization of rhoA to caveolar versus noncaveolar lipid rafts differentially regulates its activation and contractions to rhoA-dependent agonists with greater activation associated with its localization to noncaveolar rafts. Disruption of rhoA localization within caveolae may contribute to increased activation and enhanced vascular contractions in cardiovascular disease.

Involvement of rho-kinase activation in the pathogenesis of coronary hyperconstricting responses induced by drug-eluting stents in patients with coronary artery disease

BACKGROUND

Activation of Rho-kinase plays a central role in the pathogenesis of drug-eluting stents (DES)-induced coronary hyperconstricting responses in pigs in vivo has been previously demonstrated. In the present study, Rho-kinase activation involved in those responses in patients with coronary artery disease (CAD) is examined.

METHODS AND RESULTS

In 24 patients with CAD who underwent coronary intervention with either DES or bare-metal stents (BMS), coronary vasomotor responses to intracoronary acetylcholine (ACh) before and after intracoronary pre-treatment with a Rho-kinase inhibitor, fasudil was examined. Coronary vasomotor responses by quantitative coronary angiography (QCA) and coronary vascular structure by optical coherence tomography (OCT) was evaluated. QCA showed that the coronary vasoconstricting responses to ACh were significantly enhanced in the DES group compared with the BMS group both at the proximal and the distal segments adjacent to the stents (proximal: BMS -13.0±10.7% vs. DES -25.4±14.3%, P=0.036; distal: BMS -24.4±12.2% vs. DES -43.8±14.7%, P=0.003). Importantly, fasudil markedly attenuated the enhanced vasoconstricting responses to ACh in the DES group (proximal 10.2±11.7%, distal 14.4±10.5% vs. before fasudil, both P<0.01). In the OCT imaging analysis, there was no significant correlation between intimal thickness and coronary vasoconstriction to ACh.

CONCLUSIONS

These results indicate that Rho-kinase activation is substantially involved in the pathogenesis of the DES-induced coronary hyperconstricting responses in patients with CAD, suggesting the therapeutic importance of Rho-kinase pathway.

Nitric oxide: considerations for the treatment of ischemic stroke

Some 40 years ago it was recognized by Furchgott and colleagues that the endothelium releases a vasodilator, endothelium-derived relaxing factor (EDRF). Later on, several groups identified EDRF to be a gas, nitric oxide (NO). Since then, NO was identified as one of the most versatile and unique molecules in animal and human biology. Nitric oxide mediates a plethora of physiological functions, for example, maintenance of vascular tone and inflammation. Apart from these physiological functions, NO is also involved in the pathophysiology of various disorders, specifically those in which regulation of blood flow and inflammation has a key role. The aim of the current review is to summarize the role of NO in cerebral ischemia, the most common cause of stroke.

Effects of exercise training and RhoA/ROCK inhibition on plaque in ApoE-/- mice

BACKGROUND

The molecular mechanisms of exercise-induced cardioprotection are poorly understood. We recently reported that exercise training down-regulated gene expression of the Ras homolog gene family member A (RhoA). RhoA and its first effectors, the Rho-kinases (ROCK), have already been implicated in the pathogenesis of cardiovascular disease. The aim of this study was to compare the effects of a RhoA/ROCK inhibitor (fasudil) and exercise in the Apolipoprotein E knockout (ApoE(-/-)) mouse model of atherosclerosis.

METHODS

Four groups of 14 week old ApoE(-/-) mice were randomised as follows (n=12/group): i) sedentary controls (Cont); ii) fasudil (Fas) treatment (100mg/kg bodyweight/day) for 8 weeks; iii) exercise intervention (Ex:free access to running wheel for 8 weeks) and iv) exercise intervention and fasudil treatment (ExFas) for 8 weeks.

RESULTS

Phosphorylation of myosin light chain was significantly reduced in the brachiocephalic artery of all treatment groups compared with sedentary controls, implying an inhibitory effect of exercise and fasudil on the RhoA/ROCK pathway. Furthermore, atherosclerotic lesions were significantly smaller in all treatment and intervention groups compared with the control group (Fas: 34.7%, Ex: 48.3%, ExFas: 40.9% less than Control). The intima:media ratio was reduced by both exercise intervention and fasudil treatment alone or in combination (Fas: 23.6%, Ex: 35.5%, ExFas: 43.9% less than Control). Exercise alone and fasudil treatment alone also showed similar effects on plaque composition, increasing both smooth muscle cell and macrophage density.

CONCLUSION

These results suggest that the protective effects of exercise on atherogenesis are similar to the inhibitory effects on the RhoA/ROCK signalling pathway.

Acetylsalicylic acid regulates overexpressed small GTPase RhoA in vascular smooth muscle cells through prevention of new synthesis and enhancement of protein degradation

RhoA has been shown to play a major role in vascular processes and acetylsalicylic acid (aspirin) is known to exert a cytoprotective effect via multiple mechanisms. In the present study, we aimed at investigating the effect of aspirin on RhoA expression under a stress state in rat VSMCs (vascular smooth muscle cells) and the underlying mechanisms. The expression of iNOS (inducible nitric oxide synthase) and iNOS activity as well as NO concentration was significantly promoted by LPS (lipopolysaccharide) accompanying the elevation of RhoA expression, which was blocked by the addition of the iNOS inhibitor L-NIL [L-N6-(1-iminoethyl)lysine dihydrochloride]. Aspirin (30 μM) significantly attenuated the elevation of RhoA, while indomethacin and salicylate had no similar effect. The sGC (soluble guanylate cyclase) inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one) showed the same effect as aspirin in down-regulating RhoA but was reversed by the addition of the cGMP analogue 8-Br-PET-cGMP (β-phenyl-1,N2-ethano-8-bromoguanosine 3',5'-cyclic monophosphorothioate). 8-Br-PET-cGMP solely enhanced the RhoA expression that was abrogated by preincubation with aspirin. Degradation analysis indicated that aspirin enhanced the protein degradation rate of RhoA and GDP-bound RhoA seemed to be more susceptible to aspirin-enhanced degradation compared with the GTP-bound form. Our results indicate that aspirin attenuates the LPS-induced overexpression of RhoA both by inhibiting new synthesis and accelerating protein degradation, which may help elucidate the multiple beneficial effects of aspirin.

Increased epicardial adipose tissue in patients with isolated coronary artery ectasia

BACKGROUND

Epicardial adipose tissue (EAT), localized beneath the visceral pericardium, is a metabolically active endocrine and paracrine organ with possible interactions within the heart. Coronary artery ectasia (CAE) is a clinical entity characterized with localized or diffuse dilatation, of the coronary arteries, with a diameter of greater than 1.5 times that of adjacent segments. Although the etiopathogenesis is not clearly understood, some studies have revealed that CAE may be a form of atherosclerosis that has greater inflammatory properties than atherosclerosis. The goal of this study was to investigate whether EAT and the level of C-reactive protein (CRP) are increased in patients with isolated CAE compared to normal subjects.

METHODS

Thirty-three patients with isolated CAE (mean age: 57±9 years) and 32 age- and gender-matched control participants with NCA, but without CAE (mean age: 56±10 years), were included in the study. The relationship between EAT thickness, CRP levels and the presence of CAE was investigated.

RESULTS

Epicardial adipose tissue thickness was significantly higher in CAE group compared to NCA group (7.2±3.2 vs. 4.7±2.1 mm, p<0.001). Body mass index (BMI, p=0.013), CRP (p=0.047), and the percentage of isolated CAE (p=0.012) were significantly higher in patients with an increased EAT thickness. While CRP correlated with increased EAT, it was not related to CAE. However, CRP levels were higher in patients with diffuse coronary ectatic involvement than the focal lesions (0.58±0.32 vs. 0.31±0.11 mg/dL, p=0.046). When we performed multiple logistic regression analysis, only increased EAT thickness was related to CAE independent of CRP and BMI (OR: 1.442, 95%CI: 1.066-1.951, p=0.018).

CONCLUSION

This is the first study, displaying a significantly higher EAT-thickness in patients with isolated CAE. We believe that further studies are needed to clarify the role of adipose tissue in patients with isolated CAE.