Cellular and molecular mechanisms of coronary artery spasm: lessons from animal models

Role of polyunsaturated fatty acids in Japanese patients with coronary spastic angina

BACKGROUND

n-3 polyunsaturated fatty acids (PUFAs) reduce the risk of ischemic heart disease. However, there are few reports of a relationship between n-3 PUFAs and coronary spastic angina (CSA). This study aimed to assess the age-dependent role of serum levels of fatty acid in patients with CSA.

METHODS AND RESULTS

We enrolled 406 patients who underwent ergonovine tolerance test (ETT) during coronary angiography for evaluation of CSA. All ETT-positive subjects were diagnosed as having CSA. We categorized the patients by age and results of ETT as follows: (1) young (age ≤ 65 years) CSA-positive (n = 32), (2) young CSA-negative (n = 134), (3) elderly (age > 66 years) CSA-positive (n = 36), and (4) elderly CSA-negative (n = 204) groups. We evaluated the serum levels of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid, and dihomo-gamma-linolenic acid. In the young groups, the serum levels of EPA (64.3 ± 37.7 μg/mL vs. 49.4 ± 28.8 μg/mL, p = 0.015) and DHA (135.7 ± 47.6 μg/mL vs. 117.4 ± 37.6 μg/mL, p = 0.020) were significantly higher in the CSA-positive group than in the CSA-negative group, respectively. However, this was not the case with elderly groups. In the multivariate analysis in young groups, the serum levels of EPA (p = 0.028) and DHA (p = 0.049) were independently associated with the presence of CSA, respectively.

CONCLUSION

Our results suggested that the higher serum levels of EPA and/or DHA might be involved in the pathophysiology of CSA in the young population but not in the elderly population.

Surgical revascularization for severe spasm in the left main coronary artery

A 46-year-old woman who presented with severe stenosis with endothelial damage caused by recurrent spasm in the left main coronary artery received medical therapy. However, she developed severe coronary artery spasm, resulting in circulatory collapse, which was successfully treated with coronary artery bypass grafting.

Endothelium-Derived Relaxing Factors and Endothelial Function: A Systematic Review

BACKGROUND

The endothelium plays a pivotal role in homeostatic mechanisms. It specifically modulates vascular tone by releasing vasodilatory mediators, which act on the vascular smooth muscle. Large amounts of work have been dedicated towards identifying mediators of vasodilation and vasoconstriction alongside the deleterious effects of reactive oxygen species on the endothelium. We conducted a systematic review to study the role of the factors released by the endothelium and the effects on the vessels alongside its role in atherosclerosis.

METHODS

A search was conducted with appropriate search terms. Specific attention was offered to the effects of emerging modulators of endothelial functions focusing the analysis on studies that investigated the role of reactive oxygen species (ROS), perivascular adipose tissue, shear stress, AMP-activated protein kinase, potassium channels, bone morphogenic protein 4, and P2Y2 receptor.

RESULTS

530 citations were reviewed, with 35 studies included in the final systematic review. The endpoints were evaluated in these studies which offered an extensive discussion on emerging modulators of endothelial functions. Specific factors such as reactive oxygen species had deleterious effects, especially in the obese and elderly. Another important finding included the shear stress-induced endothelial nitric oxide (NO), which may delay development of atherosclerosis. Perivascular Adipose Tissue (PVAT) also contributes to reparative measures against atherosclerosis, although this may turn pathological in obese subjects. Some of these factors may be targets for pharmaceutical agents in the near future.

CONCLUSION

The complex role and function of the endothelium is vital for regular homeostasis. Dysregulation may drive atherogenesis; thus, efforts should be placed at considering therapeutic options by targeting some of the factors noted.

Cellular Mechanisms of Coronary Artery Spasm

Coronary artery spasm (CAS) is a reversible phenomenon caused by spontaneous excessive vascular smooth muscle contractility and vascular wall hypertonicity, which results in partial or complete closure of the lumen of normal or atherosclerotic coronary arteries. The clinical picture of CAS includes chest discomfort which is similar in quality to that of stable effort angina. Mechanisms underlying the development of CAS are still unclear. CAS certainly is a multifactorial disease. In this review, we paid attention to the role of the main pathophysiologic mechanisms in CAS: endothelial dysfunction, chronic inflammation, oxidative stress, smooth muscle hypercontractility, atherosclerosis and thrombosis, and mutations leading to deficient aldehyde dehydrogenase 2 (ALDH2) activity. These findings might shed novel insight on the underlying mechanisms and identify potential diagnostic and therapeutic targets for cardiovascular diseases in the future.

TLR4-Myd88 pathway upregulated caveolin-1 expression contributes to coronary artery spasm

AIM

To study the role of toll-like receptors 4-myeloid differentiation factor 88 (TLR4-Myd88) dependent caveolin-1 (Cav-1) expression modulation in coronary artery spasm (CAS) and explore the underlying pathogenic mechanisms.

METHODS AND RESULTS

Lipopolysaccharide (LPS) and acetylcholine (Ach) were used to develop the in vitro and in vivo models mimicking the physiological CAS microenvironment. LPS-induced upregulation of Cav-1 expression in mouse coronary and aorta endothelial cells was shown by western blot and immunofluorescence (IF) staining (p < 0.01). Caveolin-1-knockout (Cav-1^-/-) mice had reduced aortic inflammation after LPS challenge, and fewer ST segment changes were observed through electrocardiogram (ECG) monitoring compared to wild type mice after LPS and ACh administration. In vitro, pretreating human umbilical vein endothelial cells (HUVECs) with siCav-1 to knock down Cav-1 expression reduced the endothelial inflammation following LPS challenge. SiCav-1 also partially reversed the attenuated Ca²⁺ concentration after LPS and ACh administration compared to the control group, which was evaluated by fluorescent molecular probing for Ca²⁺ alternation monitoring (p < 0.05). TLR4 and Myd88 downregulation by siRNA partially blocked the increased Cav-1 mRNA and protein expressions following LPS treatment, as well as partially reversed the decreased NO production evaluated by nitrate reductase method and the impaired Ca²⁺ concentration of endothelial cells induced by LPS and ACh.

CONCLUSION

These findings suggested that Cav-1, which was upregulated by TLR4-Myd88, served as an important modulator of CAS microenvironment establishment in vivo and in vitro, making it a potential pharmacologic target for the treatment of vasospasm via reduced endothelial cell inflammation.

Coronary Plaque Characteristics and Cut-Off Stenosis for Developing Spasm in Patients with Vasospastic Angina

Coronary plaque distribution, frequency and cut-off value of percent stenosis for developing vasospasm are uncertain in patients with vasospastic angina (VA). We enrolled 2960 patients who received coronary angiography (CAG) and ergonovine provocation test prospectively in 11 university hospitals in Korea. A total of 1836 patients with VA and 867 without VA were included. Plaque and % stenosis were defined as ≥1% luminal narrowing and mean of each segmental stenosis. Overall frequency of plaque and % diameter stenosis was compared among VA-patients with index coronary spasm positive, those with index arterial spasm negative/other arterial spasm positive (INOP) and non-VA patients. Diameter stenosis associated with the spasm positivity was investigated. Overall plaque frequency and % stenosis were higher in VA patients than non-VA patients. Plaque frequency was 27.6% (243/881) in spasm positive at LAD, 16.4% (157/955) in LAD INOP and 12.6% (109/867) in non-VA with statistic difference (P < 0.001). Same trend for higher rate was observed in LCx and RCA. For % stenosis, 36.6 vs 32.4% (p = 0.010) in LAD, 36.1 vs. 28% (p < 0.001) in LCx and 35.3 vs.30.0% (p = 0.047) in RCA, respectively. Diameter stenosis of LAD with spasm positive vs. LAD INOP vs. non-VA were 38.3%, 34.0%, 32% (P = 0.002) with similar pattern in LCx and RCA. By multivariate logistic regression analysis, coronary stenosis of LAD ≥ 35% or LCx ≥35% or RCA ≥ 40% were independent predictor of developing spasm (OR 2.019, 95% CI 1.315–3.100, P = 0.001). In conclusions, spastic coronary artery had more plaque frequency, higher % stenosis than in non-spastic coronary in VA patients. The spasm related and unrelated coronary in VA patients had more plaque than in matched and unmatched coronary arteries in non-VA patients. Coronary stenosis ≥35% in LAD and LCx was an independent predictor of developing spasm.

Descemet Stripping Only Supplemented With Topical Ripasudil for Fuchs Endothelial Dystrophy 12-Month Outcomes of the Sydney Eye Hospital Study

PURPOSE

To report early safety and efficacy of Descemet stripping only (DSO) supplemented with ripasudil.

METHODS

A pre-post clinical trial with a historical control group for time to heal and cell count parameters. The study received ethics approval and was conducted with oversight of a data safety monitoring board. All enrolled patients had a superior endothelial cell count of >1000 cells/mm2 and were symptomatic from the presence of central guttata degrading vision and/or producing glare. DSO was carried out with a peeling technique and not combined with any other intervention. Ripasudil 0.4% was applied topically from day 1 postoperatively at a dose of 6 times/d until corneal clearance. Cases with relapse of edema were permitted to restart on ripasudil at a reduced dose of 2 drops/d for a further 2 weeks. Stopping rules with progression to a corneal graft were established. Baseline ocular and systemic investigations were carried out and repeated at varying intervals to monitor for local and systemic adverse events.

RESULTS

Twenty-three eyes of 23 patients met the inclusion criteria and underwent DSO. Twenty-two of 23 eyes achieved corneal clearance at a mean time of 4.1 weeks. In all patients achieving clearance, improvement in vision was recorded. Improvement in mean uncorrected visual acuity was 0.20 Logarithm of the minimum angle of resolution (LogMar), and improvement in mean best spectacle corrected visual acuity was 0.156 LogMar. One patient failed to clear and underwent Descemet membrane endothelial keratoplasty at week 12. Twenty-one of 22 patients achieving corneal clearance expressed satisfaction with the procedure. The commonest systemic side effect of topical ripasudil was gastrointestinal upset (24%), and the commonest local side effect was ocular irritation (43%). No patient experienced a serious adverse event in the course of the trial. Thirty-nine percent of patients experienced a relapse of edema on ceasing ripasudil, with clearance again on recommencing.

CONCLUSIONS

This trial of DSO supplemented with ripasudil included local and systemic safety analysis. We judge that this treatment option is emerging as a reliable intervention for select patients with Fuchs' Endothelial Corneal Dystrophy (FECD) with an acceptable safety profile. The observation of relapse edema is strong evidence of a drug effect. The longevity of these results remains unknown.

Coronary Artery Spasm: New Insights

Coronary artery spasm (CAS) defined by a severe reversible diffuse or focal vasoconstriction is the most common diagnosis among INOCA (ischemia with no obstructive coronary artery disease) patients irrespective to racial, genetic, and geographic variations. However, the prevalence of CAS tends to decrease in correlation with the increasing use of medicines such as calcium channel blockers, angiotensin converting enzyme inhibitor, and statins, the controlling management of atherosclerotic risk factors, and the decreased habitude to perform a functional reactivity test in highly active cardiac catheterization centers. A wide spectrum of clinical manifestations from silent disease to sudden cardiac death was attributed to this complex entity with unclear pathophysiology. Multiple mechanisms such as the autonomic nervous system, endothelial dysfunction, chronic inflammation, oxidative stress, and smooth muscle hypercontractility are involved. Regardless of the limited benefits proffered by the newly emerged cardiac imaging modalities, the provocative test remains the cornerstone diagnostic tool for CAS. It allows to reproduce CAS and to evaluate reactivity to nitrates. Different invasive and noninvasive therapeutic approaches are approved for the management of CAS. Long-acting nondihydropyridine calcium channel blockers are recommended for first line therapy. Invasive strategies such as PCI (percutaneous coronary intervention) and CABG (coronary artery bypass graft) have shown benefits in CAS with significant atherosclerotic lesions. Combination therapies are proposed for refractory cases.

Pathophysiology of atherothrombosis: Mechanisms of thrombus formation on disrupted atherosclerotic plaques

Atherothrombosis is a leading cause of cardiovascular mortality and morbidity worldwide. The underlying mechanisms of atherothrombosis comprise plaque disruption and subsequent thrombus formation. Arterial thrombi are thought to mainly comprise aggregated platelets as a result of high blood velocity. However, thrombi that develop on disrupted plaques comprise not only aggregated platelets, but also large amounts of fibrin, because plaques contain large amount of tissue factor that activate the coagulation cascade. Since not all thrombi grow large enough to occlude the vascular lumen, the propagation of thrombi is also critical in the onset of adverse vascular events. Various factors such as vascular wall thrombogenicity, local hemorheology, systemic thrombogenicity and fibrinolytic activity modulate thrombus formation and propagation. Although the activation mechanisms of platelets and the coagulation cascade have been intensively investigated, the underlying mechanisms of occlusive thrombus formation on disrupted plaques remain obscure. Pathological findings derived from humans and animal models of human atherothrombosis have uncovered pathophysiological processes during thrombus formation and propagation after plaque disruption, and novel factors have been identified that modulate the activation of platelets and the coagulation cascade. These findings have also provided insights into the development of novel drugs for atherothrombosis.

Myocardial bridging is an independent predictor of positive spasm provocation testing by intracoronary ergonovine injections: a retrospective observational study

The relationship between myocardial bridging (MB) and coronary spasms during spasm provocation testing (SPT) remains unclear. We aimed to investigate whether MB was correlated with the SPT by ergonovine (ER) injections in a retrospective observational study. Of the 3340 patients who underwent a first coronary angiography, 166 underwent SPT using ER injections and were divided into 2 groups: MB(+) (n = 23), and MB(−) (n = 143). MB was defined as an angiographic reduction in the diameter of the coronary artery during systole. The patients who had severe organic stenosis in the left anterior descending coronary artery were excluded. The MB(+) group more frequently had diabetes mellitus and chronic kidney disease, and a thicker interventricular septum thickness. The rate of SPT-positivity was higher in the MB(+) group than MB(−) group (56.5% vs. 22.4%, P = 0.001). A multivariate regression analysis showed that the presence of MB was independently associated with SPT-positivity (odds ratio 5.587, 95% confidence interval 2.061–15.149, P = 0.001). In conclusion, coronary spasms during provocation tests with ER independently correlated with the MB. MB may predict coronary spasms.

The Biochemical Markers Associated with the Occurrence of Coronary Spasm

Coronary artery spasm (CAS) is one of the mechanisms of angina pectoris. Unlike the diagnosis of acute myocardial infarction which is based on the elevation of cardiac markers, the diagnosis of CAS is difficult and sometimes requires sophisticated and risky provocative test which is not widely accepted in China. There is no well-established biomarker for the diagnosis or prediction of CAS. However, there are some biomarkers proven to be associated with the occurrence of CAS. For example, inflammatory factors including C-reactive protein and cytokines, lipoprotein (a), and cystatin-C might be precipitating factor for CAS. Rho-kinase as a mediator involved in multiple mechanisms of CAS, serotonin, and endothelin-1 as powerful vasoconstrictors leading to vasospasm were all observed being elevated in patients with CAS. Thioredoxin and nitrotyrosine reflected the oxidative status and could be observed to be elevated after the occurrence of CAS. In some cases doubted to be CAS without the evidence of provocative test, the blood test for the biomarkers mentioned above could be useful for the diagnosis of CAS.

Recognition and treatment of ischemic heart diseases in women

Heart disease is the leading cause of death among women in the industrialized world. However, women after myocardial infarctions (MIs) are less likely to receive preventive medications or revascularization and as many as 47% experience heart failure, stroke or die within 5 years. Premenopausal women with MIs frequently have coronary plaque erosions or dissections. Women under 50 years with angina and nonobstructive epicardial coronary artery disease often have coronary microvascular dysfunction (CMD) with reductions in coronary flow reserve that may require nontraditional therapies. In women with coronary artery disease treated with stents, the 3-year incidence of recurrent MI or death is 9.2%. Coronary bypass surgery operative mortality averages 4.6% for women compared with 2.4% in men. Addition of internal mammary artery and radial artery coronary grafts in women does not increase operative survival but improves 5-year outcome to greater than 80%.

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.

Sudden coronary death in the young: Evidence of contractile phenotype of smooth muscle cells in the culprit atherosclerotic plaque

BACKGROUND

Culprit coronary atherosclerotic plaques (APs) from young sudden cardiac death (SCD) victims are mostly non-atheromatous, i.e., consisting of proliferative smooth muscle cells (SMCs). Coronary vasospasm has been advocated to explain plaque instability in the absence of thrombosis. Our aim was to characterize the SMC phenotype in the intima and media of coronary arteries from young SCD victims.

METHODS AND RESULTS

A total of 38 coronary artery segments were studied: (a) 18 APs from young (≤40 years old) SCD patients, (b) 9 APs from old (>40 years old) SCD patients, (c) 11 non-atherosclerotic coronary arteries from young patients (≤40 years old). Markers of differentiated SMCs such as α-smooth muscle actin (α-SMA), smooth muscle myosin heavy chains (SMMHCs), and heavy-caldesmon (h-CaD), were assessed in intima and media by immunohistochemistry and quantified morphometrically. In the intima, their expression was higher in non-atherosclerotic arteries (44.37 ± 3.03% for α-SMA, 14.21 ± 2.01% for SMMHCs, 8.90 ± 1.33% for h-CaD) and APs from young SCD victims (38.95 ± 2.29% for α-SMA, 11.92 ± 1.92% for SMMHCs, 8.93 ± 1.12% for h-CaD) compared with old patients (22.01 ± 3.56% for α-SMA, 6.39 ± 0.7% for SMMHCs, 3.00 ± 0.57% for h-CaD; all P statistically significant). The media of non-atherosclerotic arteries and APs from young SCD victims exhibited strong positivity for the differentiation markers unlike that of old patients.

CONCLUSIONS

SMCs of coronary APs as well as from the underlying media from young SCD victims exhibit strong contractile phenotype. In the setting of critical stenosis, both intima and media SMC contractility might contribute to transient coronary spasm leading to myocardial ischemia and SCD.

Coronary spasm: It’s common, but it’s still unsolved

Coronary spasm is caused by a transient coronary narrowing due to the constriction of epicardial coronary artery, which leads to myocardial ischemia. More than 50 years have passed since the first recognition of coronary spasm, and many findings on coronary spasm have been reported. Coronary spasm has been considered as having pivotal roles in the cause of not only rest angina but also exertional angina, acute coronary syndrome, and heart failure. In addition, several new findings of the mechanism of coronary spasm have emerged recently. The diagnosis based mainly on coronary angiography and spasm provocation test and the mainstream treatment with a focus on a calcium-channel blocker have been established. At a glance, coronary spasm or vasospastic angina (VSA) has become a common disease. On the contrary, there are several uncertain or unsolved problems regarding coronary spasm, including the presence of medically refractory coronary spasm (intractable VSA), or an appropriate use of implantable cardioverter defibrillator in patients with cardiac arrest who have been confirmed as having coronary spasm. This editorial focused on coronary spasm, including recent topics and unsolved problems.

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.

High susceptibility of atherosclerotic coronary arteries to the onset of vasospasm and angina pectoris-like symptoms due to coronary spasm in WHHLMI rabbits

We examined the relationship between atherosclerosis and the provocation of coronary spasm as well as the influence of coronary spasm on the onset of acute ischemic myocardial disease. Coronary spasm was provoked in anesthetized normal Japanese white (JW) rabbits and myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHLMI) rabbits, an animal model for coronary atherosclerosis and myocardial infarction, by injecting ergonovine during the infusion of norepinephrine through a marginal ear vein. A decrease in contrast flow in the left circumflex artery was observed on coronary angiograms. Ischemic changes were observed on the electrocardiograms of 29% (2/7) of JW and 79% (27/34, P=0.007) of WHHLMI rabbits. The frequency of coronary spasm was significantly high in rabbits with severe coronary plaques showing diffuse lesions. Left ventricle motility in vasospasm-positive rabbits, which was evaluated with echocardiograms, was decreased by 29% following the ergonovine injection (P<0.001), and every serum ischemic marker markedly increased 4 h after the provocation of vasospasm. These results demonstrate that atherosclerotic coronary arteries are positively related to the provocation of vasospasm, and vasospasm in severe atherosclerotic coronary segments evokes angina pectoris-like findings and/or non-fatal myocardial infarction. WHHLMI rabbits may be a novel animal model for angina pectoris and acute ischemic heart disease.

Light and Dark of Reactive Oxygen Species for Vascular Function: 2014 ASVB (Asian Society of Vascular Biology)

Vascular-derived hydrogen peroxide (H2O2) serves as an important signaling molecule in the cardiovascular system and contributes to vascular homeostasis. H2O2 is a second messenger, transducing the oxidative signal into biological responses through posttranslational protein modification. The balance between oxidant and antioxidant systems regulates intracellular redox status, and their imbalance causes oxidative or reductive stress, leading to cellular damage in cardiovascular systems. Excessive H2O2 deteriorates vascular functions and promotes vascular disease through multiple pathways. The RhoA/Rho-kinase pathway plays an important role in various fundamental cellular functions, including production of excessive reactive oxygen species, leading to the development of cardiovascular diseases. Rho-kinase (ROCK1 and ROCK2) belongs to the family of serine/threonine kinases and is an important downstream effector of the small GTP-binding protein RhoA. Rho-kinase plays a crucial role in the pathogenesis of vasospasm, arteriosclerosis, ischemia/reperfusion injury, hypertension, pulmonary hypertension, stroke, and heart failure. Thus, Rho-kinase inhibitors may be useful for the treatment of cardiovascular diseases in humans. In this review, we will briefly discuss the roles of vascular-derived H2O2 and review the recent progress in the translational research on the therapeutic importance of the Rho-kinase pathway in cardiovascular medicine.

2015 ATVB Plenary Lecture: translational research on rho-kinase in cardiovascular medicine

Rho-kinase (ROCKs) is an important downstream effector of the small GTP-binding protein Ras homolog gene family member A. There are 2 isoforms of ROCK, ROCK1 and ROCK2, and they have different functions in several vascular components. The Ras homolog gene family member A/ROCK pathway plays an important role in various fundamental cellular functions, including contraction, motility, proliferation, and apoptosis, whereas its excessive activity is involved in the pathogenesis of cardiovascular diseases. For the past 20 years, a series of translational research studies have demonstrated the important roles of ROCK in the pathogenesis of cardiovascular diseases. At the molecular and cellular levels, ROCK upregulates several molecules related to inflammation, thrombosis, and fibrosis. In animal experiments, ROCK plays an important role in the pathogenesis of vasospasm, arteriosclerosis, hypertension, pulmonary hypertension, and heart failure. Finally, at the human level, ROCK is substantially involved in the pathogenesis of coronary vasospasm, angina pectoris, hypertension, pulmonary hypertension, and heart failure. Furthermore, ROCK activity in circulating leukocytes is a useful biomarker for the assessment of disease severity and therapeutic responses in vasospastic angina, heart failure, and pulmonary hypertension. In addition to fasudil, many other ROCK inhibitors are currently under development for various indications. Thus, the ROCK pathway is an important novel therapeutic target in cardiovascular medicine.

Serious cardiac complications in coronary spasm provocation tests using acetylcholine or ergonovine: analysis of 21 512 patients from the diagnosis procedure combination database in Japan

BACKGROUND

Previous studies on complications with coronary spasm provocation tests were based on small sample sizes or were limited to high-volume centers. The risk of provocation tests using acetylcholine (ACH) or ergonovine (ER) remains to be fully examined by a large-scale multicenter study.

HYPOTHESIS

ACH provocation tests are associated with a higher rate of serious cardiac complications than ER tests.

METHODS

Using the Diagnosis Procedure Combination database in Japan, we identified patients aged ≥20 years who underwent a pharmacological provocation test during coronary angiography. We assessed the composite outcome of cardiac complications requiring urgent procedures (defibrillation, chest compression, intra-aortic balloon pumping, or extracorporeal membrane oxygenation) or death on the day of the provocation test, and compared the outcome between ACH and ER tests.

RESULTS

Of 21 512 eligible patients in 602 hospitals, 10 628 (49.4%) underwent an ACH test and 10 884 (50.6%) underwent an ER test. The composite outcome occurred in 141 (0.7%) patients. The ACH group was significantly more likely to have the composite outcome than the ER group (0.9% vs 0.4%, P < 0.001). The propensity-score analyses showed consistent results (propensity score-matched, 0.9% vs 0.4%, P = 0.003; inverse probability-weighted, 0.8% vs 0.4%, P < 0.001). In a multivariable logistic regression analysis, ACH tests were significantly associated with a higher rate of the composite outcome than ER tests (odds ratio: 1.75, 95% confidence interval: 1.13-2.69, P = 0.011).

CONCLUSIONS

This retrospective cohort study suggested that ACH tests were associated with a higher rate of cardiac complications than ER tests.

Effect of oxidative stress on Rho kinase II and smooth muscle contraction in rat stomach

Recent studies have shown that both Rho kinase signaling and oxidative stress are involved in the pathogenesis of a number of human diseases, such as diabetes mellitus, hypertension, and atherosclerosis. However, very little is known about the effect of oxidative stress on the gastrointestinal (GI) smooth muscle Rho kinase pathway. The aim of the current study was to investigate the effect of oxidative stress on Rho kinase II and muscle contraction in rat stomach. The peroxynitrite donor 3-morpholinosydnonimine (SIN-1), hydrogen peroxide (H2O2), and peroxynitrite were used to induce oxidative stress. Rho kinase II expression and ACh-induced activity were measured in control and oxidant-treated cells via specifically designed enzyme-linked immunosorbent assay (ELISA) and activity assay kits, respectively. Single smooth muscle cell contraction was measured via scanning micrometry in the presence or absence of the Rho kinase blocker, Y-27632 dihydrochloride. All oxidant agents significantly increased ACh-induced Rho kinase II activity without affecting its expression level. Most important, oxidative stress induced by all three agents augmented ACh-stimulated muscle cell contraction, which was significantly inhibited by Y-27632. In conclusion, oxidative stress activates Rho kinase II and enhances contraction in rat gastric muscle, suggesting an important role in GI motility disorders associated with oxidative stress.

[Effect of repeated oral treatment with etoposide on the expression of intestinal P-glycoprotein and oral morphine analgesia]

Currently, the World Health Organization recommends oral administration of opioid analgesics for patients with cancer to treat cancer-related pain from the initial stage of treatment. Furthermore, many anticancer drugs have been newly-developed and approved as oral form. Because of this trend, the chances of drug-drug interactions between anticancer drugs and opioid analgesics during absorption process from the intestine are likely to increase. To investigate these possible drug-drug interactions, we have focused on intestinal P-glycoprotein (P-gp) which regulates the absorption of various substrate drugs administered orally. Previously, we have found that repeated oral treatment with etoposide (ETP), an anticancer drug, attenuates analgesia of oral morphine, a substrate drug for P-gp, by increasing the expression and activity of intestinal P-gp. However, the mechanism by which ETP treatment increases the intestinal P-gp expression and decreases oral morphine analgesia remains unclear. RhoA, a small G-protein, and ROCK, an effector of RhoA, pathway has been attracted attention with regard to their involvement in the regulatory mechanism of the expression and activity of P-gp. Interestingly, this pathway is activated in response to various signaling induced by some anticancer drugs. Furthermore, it has been reported that ezrin/radixin/moesin (ERM) play a key role in the plasma membrane localization of P-gp, and that RhoA/ROCK pathway regulates the activation process of ERM. This review article introduces the result of our previous research as well as recent findings on the involvement of ERM via activation of RhoA/ROCK in the increased expression of intestinal P-gp and decreased oral morphine analgesia induced by repeated oral treatment with ETP.

2014 Williams Harvey Lecture: importance of coronary vasomotion abnormalities-from bench to bedside

Coronary vasomotion abnormalities play important roles in the pathogenesis of ischaemic heart disease, in which endothelial dysfunction and coronary artery spasm are substantially involved. Endothelial vasodilator functions are heterogeneous depending on the vessel size, with relatively greater role of nitric oxide (NO) in conduit arteries and predominant role of endothelium-derived hyperpolarizing factor (EDHF) in resistance arteries, where endothelium-derived hydrogen peroxide serves as an important EDHF. The functions of NO synthases in the endothelium are also heterogeneous with multiple mechanisms involved, accounting for the diverse functions of the endothelium in vasomotor as well as metabolic modulations. Cardiovascular abnormalities and metabolic phenotypes become evident when all three NO synthases are deleted, suggesting the importance of both NO and EDHF. Coronary artery spasm plays important roles in the pathogenesis of a wide range of ischaemic heart disease. The central mechanism of the spasm is hypercontraction of vascular smooth muscle cells (VSMCs), but not endothelial dysfunction, where activation of Rho-kinase, a molecular switch of VSMC contraction, plays a major role through inhibition of myosin light-chain phosphatase. The Rho-kinase pathway is also involved in the pathogenesis of a wide range of cardiovascular diseases and new Rho-kinase inhibitors are under development for various indications. The registry study by the Japanese Coronary Spasm Association has demonstrated many important aspects of vasospastic angina. The ongoing international registry study of vasospastic angina in six nations should elucidate the unknown aspects of the disorder. Coronary vasomotion abnormalities appear to be an important therapeutic target in cardiovascular medicine.

Adenosine-induced coronary vasospasm following drug-eluting stent implantation

We present the case of coronary vasospasm during adenosine stress in a patient with a prior drug-eluting stent implantation. The patient had a stent implantation in the left anterior descending coronary artery 3 years ago. Recently, he developed a chest pain and underwent adenosine stress myocardial perfusion single photon emission CT (SPECT). During the adenosine stress, he felt severe chest pain and ST elevation on electrocardiogram. An invasive coronary angiography showed no in-stent restenosis. This phenomenon deemed to be adenosine-induced coronary vasospasm after stent implantation.

Coronary artery spasm: review and update

Coronary artery spasm (CAS), an intense vasoconstriction of coronary arteries that causes total or subtotal vessel occlusion, plays an important role in myocardial ischemic syndromes including stable and unstable angina, acute myocardial infarction, and sudden cardiac death. Coronary angiography and provocative testing usually is required to establish a definitive diagnosis. While the mechanisms underlying the development of CAS are still poorly understood, CAS appears to be a multifactorial disease but is not associated with the traditional risk factors for coronary artery disease. The diagnosis of CAS has important therapeutic implications, as calcium antagonists, not β-blockers, are the cornerstone of medical treatment. The prognosis is generally considered benign; however, recurrent episodes of angina are frequently observed. We provide a review of the literature and summarize the current state of knowledge regarding the pathogenesis of CAS.

Involvement of PtdIns(4,5)P2 in the regulatory mechanism of small intestinal P-glycoprotein expression

Previously, we reported that repeated oral administration of etoposide (ETP) activates the ezrin/radixin/moesin (ERM) scaffold proteins for P-glycoprotein (P-gp) via Ras homolog gene family member A (RhoA)/Rho-associated coiled-coil containing protein kinase (ROCK) signaling, leading to increased ileal P-gp expression. Recent studies indicate that phosphatidyl inositol 4,5-bisphosphate [PtdIns(4,5)P2] regulates the plasma-membrane localization of certain proteins, and its synthase, the type I phosphatidyl inositol 4-phosphate 5-kinase (PI4P5K), is largely controlled by RhoA/ROCK. Here, we examined whether PtdIns(4,5)P2 and PI4P5K are involved in the increased expression of ileal P-gp following the ERM activation by ETP treatment. Male ddY mice (4-week-old) were treated with ETP (10 mg/kg/day, per os, p.o.) for 5 days. Protein-expression levels were measured by either western blot or dot blot analysis and molecular interactions were assessed using immunoprecipitation assays. ETP treatment significantly increased PI4P5K, ERM, and P-gp expression in the ileal membrane. This effect was suppressed following the coadministration of ETP with rosuvastatin (a RhoA inhibitor) or fasudil (a ROCK inhibitor). Notably, the PtdIns(4,5)P2 expression in the ileal membrane, as well as both P-gp and ERM levels coimmunoprecipitated with anti-PtdIns(4,5)P2 antibody, were increased by ETP treatment. PtdIns(4,5)P2 and PI4P5K may contribute to the increase in ileal P-gp expression observed following the ETP treatment, possibly through ERM activation via the RhoA/ROCK pathway.

Coronary artery spasm related to thiol oxidation and senescence marker protein-30 in aging

BACKGROUND

Senescence marker protein-30 (SMP30) decreases with aging, and SMP30 knockout (KO) mice show a short life with increased oxidant stress.

AIMS

We assessed the effect of oxidant stress with SMP30 deficiency in coronary artery spasm and clarify its underlying mechanisms.

RESULTS

We measured vascular responses to acetylcholine (ACh) and sodium nitroprusside (SNP) of isolated coronary arteries from SMP30 KO and wild-type (WT) mice. In SMP30 KO mice, ACh-induced vasoconstriction occurred, which was changed to vasodilation by dithiothreitol (DTT), a thiol-reducing agent. However, Nω-nitro-L-arginine-methyl ester, nitric oxide (NO) synthase inhibitor, or tetrahydrobiopterin did not change the ACh response. In isolated coronary arteries of WT mice, ACh-induced vasodilation occurred. Inhibition of glutathione reductase by 1, 3-bis(2-chloroethyl)-1-nitrosourea decreased ACh-induced vasodilation (n=10, p<0.01), which was restored by DTT. To evaluate the thiol oxidation, we measured the fluorescence of monochlorobimane (MCB) in coronary arteries, which covalently labels the total. The fluorescence level to MCB decreased in SMP30 KO mice, but with DTT treatment restored to a level comparable to that of WT mice. The reduced glutathione and total thiol levels were also low in the aorta of SMP30 KO mice compared with those of WT mice. Administration of ACh into the aortic sinus in vivo of SMP30 KO mice induced coronary artery spasm.

INNOVATION

The thiol redox state is a key regulator of endothelial NO synthase activity, and thiol oxidation was associated with endothelial dysfunction in the SMP30 deficiency model.

CONCLUSION

These results suggest that chronic thiol oxidation by oxidant stress is a trigger of coronary artery spasm, resulting in impaired endothelium-dependent vasodilation.

Acute myocardial infarction with normal coronary arteries associated with subclinical Graves disease

Myocardial infarction occurring with angiographically normal coronary arteries is rare and often described in young people. This report describes a case of myocardial infarction with normal coronary arteries in a young female patient related to coronary thrombosis complicated by left ventricular apical thrombus in the setting of an unknown and subclinical Graves disease.

Age-related oxidant stress with senescence marker protein-30 deficiency plays a pivotal role in coronary artery spasm

OBJECTIVES

We examined the mechanism of coronary artery spasm related to oxidant stress with aging in senescence marker protein-30 (SMP30)-deficient mice because SMP30 decreases with aging and SMP30 knockout (KO) mice show a short life with increased oxidant stress.

METHODS

To examine the effect of SMP30 on coronary artery vasomotor tone, we measured the endothelium-dependent [5-hydroxytryptamine (5-HT)] response of isolated, pressurized coronary arteries from SMP30 KO and wild-type (WT) mice (n=10 each).

RESULTS

In SMP30 KO mice, 5-HT-induced vasoconstriction occurred, which altered vasodilation with dithiothreitol, a thiol-reducing agent. In WT mice, 5-HT-induced vasodilation occurred. Administration of 5-HT from the aortic sinus induced a coronary artery spasm in SMP30 KO mice, which was prevented by the intravenous administration of Y-27632, rho-kinase inhibitor. The fluorescence level of monochlorobimane in coronary arteries, which covalently labels the reduced total thiols, decreased in SMP30 KO mice, but reverted to a level comparable with that of WT mice on treatment with Y-27632. From these results, SMP30 provides protection against coronary artery spasm.

CONCLUSION

Chronic oxidant stress associated with aging plays an important role in coronary artery spasm related to thiol oxidation and rho-kinase signaling.

Higher serum uric acid and lipoprotein(a) are correlated with coronary spasm

It has been reported that a major cause of coronary vasospastic angina (VSA) is endothelial dysfunction of the coronary artery. On the other hand, some studies showed that serum uric acid and lipoprotein(a) are correlated with endothelial dysfunction. Thus, we examined whether uric acid and lipoprotein(a), are correlated with VSA. Four hundred forty-one patients with suspected VSA who underwent a coronary angiogram with acetylcholine provocation (ACh test) during an 8-year period were enrolled. We divided them into a VSA group, who showed coronary spasm by the ACh test, and an atypical chest pain (ACP) group, who showed negative ACh test. We compared serum markers between the two groups, including low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, high-sensitivity C-reactive protein (hs-CRP), lipoprotein(a), fibrinogen, total plasminogen activator inhibitor-1, and uric acid. Uric acid, hs-CRP, and lipoprotein(a) were significantly higher in the VSA group than in the ACP group (all P < 0.05) while there were no significant differences in the other parameters. Multivariate analyses identified uric acid and lipoprotein(a) as significant independent markers for VSA. Uric acid and lipoprotein(a) are correlated with VSA, and medical intervention to decrease uric acid and lipoprotein(a) might be effective in controlling VSA.

A case of Prinzmetal angina diagnosed by Holter monitoring who survived a sudden cardiac death: Case report

A 47-year-old female patient was admitted to our hospital after a syncope. She reported episodes of angina in previous weeks. On admission, there were no electrocardiographic changes but elevated troponin. Coronary angiogram showed minimal arteriosclerosis and normal left ventricle. Holter monitoring showed severe ST-segment changes during an anginal episode.With calcium antagonists, the patient experienced no further episodes of angina or ST changes during telemetry.Six weeks later, calcium antagonist was stopped for unknown reason. After that, the patient experienced a second prolonged syncope with cardiopulmonary resuscitation and defibrillation of ventricular fibrillation.

DISCUSSION

"A variant form of angina pectoris" was first described by Myron Prinzmetal. He postulated coronary vasospasm as the underlying cause, however, after 50 years the exact pathophysiology is still not known.Patients with "variant angina" usually present with "spontaneous" attacks of typical retrosternal anginal pain during rest or normal activities, but not with physical exercise.Sudden cardiac deaths were reported in patients with Prinzmetal angina in only a few case reports.

CONCLUSION

In cases of variant angina accompanied by syncope, a provocation test and an electrophysiological study should be considered.

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.

Clinical implications of provocation tests for coronary artery spasm: safety, arrhythmic complications, and prognostic impact: multicentre registry study of the Japanese Coronary Spasm Association

AIMS

Provocation tests of coronary artery spasm are useful for the diagnosis of vasospastic angina (VSA). However, these tests are thought to have a potential risk of arrhythmic complications, including ventricular tachycardia (VT), ventricular fibrillation (VF), and brady-arrhythmias. We aimed to elucidate the safety and the clinical implications of the spasm provocation tests in the nationwide multicentre registry study by the Japanese Coronary Spasm Association.

METHODS AND RESULTS

A total of 1244 VSA patients (M/F, 938/306; median 66 years) who underwent the spasm provocation tests were enrolled from 47 institutes. The primary endpoint was defined as major adverse cardiac events (MACEs). The provocation tests were performed with either acetylcholine (ACh, 57%) or ergonovine (40%). During the provocation tests, VT/VF and brady-arrhythmias developed at a rate of 3.2 and 2.7%, respectively. Overall incidence of arrhythmic complications was 6.8%, a comparable incidence of those during spontaneous angina attack (7.0%). Multivariable logistic regression analysis demonstrated that diffuse right coronary artery spasm (P < 0.01) and the use of ACh (P < 0.05) had a significant correlation with provocation-related VT/VF. During the median follow-up of 32 months, 69 patients (5.5%) reached the primary endpoint. The multivariable Cox proportional hazard model revealed that mixed (focal plus diffuse) type multivessel spasm had an important association with MACEs (adjusted hazard ratio, 2.84; 95% confidence interval, 1.34-6.03; P < 0.01), whereas provocation-related arrhythmias did not.

CONCLUSION

The spasm provocation tests have an acceptable level of safety and the evaluation of spasm type may provide useful information for the risk prediction of VSA patients.

Rho-associated kinase 2 polymorphism in patients with vasospastic angina

Background and Objectives

Recent studies indicate that in response to vasoconstrictor stimuli, the small GTPase RhoA and its down-stream effector, Rho-associated kinase 2 (ROCK)/Rho-kinase, are associated with hypercontraction of the vascular smooth muscle of coronary arteries through augmentation of myosin light chain phosphorylation and Ca²⁺ sensitization. Expression of ROCK/Rho-kinase mRNA was significantly increased and up-regulated in the spastic coronary artery in a porcine model, and a specific inhibitor of ROCK/Rho-kinase inhibited coronary artery spasm in humans. We therefore explored the role of ROCK2 polymorphisms in the pathogenesis of vasospastic angina (VA).

Subjects and Methods

We studied 106 patients with VA who exhibited spontaneous or provoked coronary spasm during coronary angiography and compared the prevalence of ROCK2 polymorphisms between this group of patients with VA and controls whose angiograms were normal, and in whom the ergonovine test did not cause spasm (n=107). Five single nucleotide polymorphisms (SNPs) of the ROCK2 gene were selected. SNPs were genotyped by high-resolution melting. Linkage disequilibrium and haplotype analyses were performed using the SHEsis program.

Results

The prevalence of genotypes of the 5 interesting SNPs in patients with VA was not different from that in the control group. In haplotype analysis, the haplotype G-T-C-T-G (in order of rs978906, rs2271621, rs2230774, rs1515210, and rs3771106) was significantly associated with a decreased risk of VA (p=0.007).

Conclusion

The haplotype G-T-C-T-G in the ROCK2 gene had a protective effect against VA, suggesting the involvement of ROCK2 in VA pathogenesis.

Long-term administration of fasudil improves cardiomyopathy in streptozotocin-induced diabetic rats

Inhibition of Rho kinase (ROCK) has been shown to improve diabetic-related disorders. In this study, the cardio-protective effects and potential mechanisms of fasudil, a selective ROCK inhibitor, on diabetic cardiomyopathy were investigated in a streptozotocin (STZ)-induced diabetic rat model. Eight weeks after diabetes was induced by a single tail vein injection of 60 mg/kg STZ, rats were administered long-term fasudil or captopril as a control over a four-week period. Similar to the effect of captopril, fasudil treatment significantly protected against STZ-induced hemodynamic, histopathologic changes and decreased serum lactate dehydrogenase and creatine phosphokinase. Moreover, fasudil significantly down-regulated ROCK I mRNA expression and ROCK activity, reduced cardiac collagen deposition, and decreased the incidence of apoptosis and ratio of Bax/Bcl-2 protein expression. Additionally, fasudil potently elevated superoxide dismutase activity and suppressed the extent of lipid peroxidation in sera and hearts of diabetic rats. Our findings indicated that long-term treatment with fasudil could improve cardiac dysfunction, attenuate myocardial injury and prevent pathological changes in a rat model of diabetic cardiomyopathy. These effects could be attributed to regulation of antioxidative activities, suppression of myocardial hypertrophy, apoptosis, fibrosis and subsequent cardiac remodeling. These results may help to expand the clinical application of fasudil for diabetic cardiomyopathy.

Conformational change in coronary artery structure assessed by optical coherence tomography in patients with vasospastic angina

OBJECTIVES

The aim of this study was to investigate the conformational change of arterial structure in the vasospastic lesion with optical coherence tomography.

BACKGROUND

Coronary artery spasm plays an important role in the pathogenesis of ischemic heart diseases. The conformational change of each arterial layer during vasospasm has not been studied in detail.

METHODS

We assessed 19 coronary arteries (10 spasm and 9 nonspasm lesions) with optical coherence tomography during the provocation test for coronary spasm. An intimal bump was defined as 1 or more intimal projections into the lumen that disappeared after the administration of nitroglycerine (NTG). Intimal gathering was defined as a folding/gathering of the intima, resulting in multiple kinks in the luminal contour that resolved after the administration of NTG.

RESULTS

The spasm lesion more frequently showed an intimal bump at baseline and intimal gathering during spasm compared with the nonspasm lesion (spasm 80% vs. nonspasm 0%, p < 0.01, spasm 100% vs. nonspasm 0%, p < 0.01, respectively). The spasm lesion demonstrated a thicker maximum media thickness (spasm 0.24 ± 0.04 mm vs. nonspasm 0.12 ± 0.03 mm, p < 0.01) at baseline, whereas no differences were observed after the administration of NTG (spasm 0.13 ± 0.03 mm vs. nonspasm 0.13 ± 0.02 mm, p = 0.65).

CONCLUSIONS

Our results suggest that medial contraction occurs even in an asymptomatic state and facilitates the formation of an intimal bump in patients with vasospastic angina. Luminal narrowing during spasm is associated with intimal gathering without alteration of intimal area.

Enhanced Rho-kinase activity in circulating neutrophils of patients with vasospastic angina: a possible biomarker for diagnosis and disease activity assessment

OBJECTIVES

The aim of this study was to examine whether Rho-kinase activity is systemically enhanced in patients with vasospastic angina (VSA) and, if so, whether a noninvasive diagnostic method could be developed to improve practice.

BACKGROUND

The activated Rho-kinase pathway plays a central role in the molecular mechanism of coronary vasospasm in animal models and patients with VSA. Recently, it has been reported that Rho-kinase activity in circulating leukocytes is associated with various diseases.

METHODS

Fifty-three consecutive patients with chest pain who underwent acetylcholine provocation testing for coronary spasm were examined. Patients were divided into 2 groups depending on their response to the test: VSA (n = 33) and non-VSA (n = 20) groups. Venous blood samples were collected to measure Rho-kinase activity in circulating neutrophils, determined by the extent of phosphorylation of myosin-binding subunit (MBS), a substrate of Rho-kinase.

RESULTS

Rho-kinase activity was significantly higher in the VSA group than in the non-VSA group (phosphorylated MBS/total MBS ratio 1.33 ± 0.37 vs. 0.95 ± 0.22, p < 0.001). In the VSA group, no correlation was noted between Rho-kinase activity and high-sensitivity C-reactive protein, smoking, or accumulated number of coronary risk factors. After the 3-month medical treatment, Rho-kinase activity in the VSA group was significantly decreased to 1.08 ± 0.31 (p < 0.001). On receiver-operating characteristic curve analysis, a phosphorylated MBS ratio of 1.18 was identified as the best cutoff level to predict the diagnosis of VSA.

CONCLUSIONS

These results indicate that Rho-kinase activity in circulating neutrophils is enhanced in patients with VSA and may be a useful biomarker for diagnosis and disease activity assessment of the vasospastic disorder.