Plasma endothelin-1 levels in patients with angina pectoris and normal coronary angiograms.
ABSTRACT Some patients with typical angina and electrocardiographic evidence of ischemia have normal coronary angiograms. These patients have a reduced coronary flow reserve and abnormal endothelium-dependent vasodilator responses; this syndrome is known as microvascular angina. Among endothelium-derived peptides, endothelin-1 (ET-1) is a potent vasoconstrictor and an important modulator of microvascular function.
Plasma ET-1 was measured in 13 patients with typical angina, instrumental evidence of ischemia, and normal arteriograms and in 20 normal control subjects.
Mean concentration of ET-1 was 2.89+/-1.24 pmol/L in patients with angina and normal angiograms and 1.99+/-0.81 pmol/L in normal control subjects (p < 0.02). Plasma levels of ET-1 values were significantly higher in patients with angina, positive exercise test results for ischemia, and normal coronary arteriograms compared with the group of patients with no clinical or instrumental evidence of ischemia.
This is consistent with the hypothesis that in patients with microvascular angina, an endothelial dysfunction in the coronary vascular area caused by impaired endothelium-derived ET-1 could play an active role in the disease process.
[show abstract] [hide abstract]
ABSTRACT: 1. Chuanxiong is a Chinese herb that has been used widely in China to treat vascular disorders. 2,3,5,6-Tetramethylpyrazine (TMP) is one of the major components purified from chuanxiong. Many studies have demonstrated that TMP is effective in the treatment of cardiovascular diseases. However, the mechanism of action by which TMP exerts relaxation in vascular vessels remains unclear. 2. Endothelin (ET)-1 is a potent vasopressor synthesised by endothelial cells both in culture and in vivo. The aims of the present study were to test the hypothesis that TMP may alter strain-induced ET-1 secretion and to identify the putative underlying signalling pathways in endothelial cells. 3. We showed that TMP inhibits strain-induced ET-1 secretion. 2,3,5,6-Tetramethylpyrazine also inhibits the strain-induced formation of reactive oxygen species (ROS) and phosphorylation of extracellular signal-regulated kinases (ERK) 1/2. Furthermore, pretreating cells with TMP or the anti-oxidant N-acetyl-cysteine decreased strain-induced increases in ET-1 secretion and ERK1/2 phosphorylation. Using a reporter gene assay, TMP and N-acetyl-cysteine were demonstrated to also attenuate the strain-induced activity of the activator protein-1 reporter. 4. In summary, we have demonstrated, for the first time, that TMP inhibits strain-induced ET-1 gene expression, in part by interfering with the ERK1/2 pathway via attenuation of ROS formation. Thus, the present study provides important new insights into the molecular pathways that may contribute to the proposed beneficial effects of TMP in the vascular system.Clinical and Experimental Pharmacology and Physiology 08/2005; 32(7):536-40. · 1.85 Impact Factor
[show abstract] [hide abstract]
ABSTRACT: Angina in the absence of obstructive coronary artery disease, sometimes referred to as cardiac syndrome X (CSX), is a debilitating condition that disproportionately affects women. More than 50% of women evaluated for angina have non-obstructive disease by cardiac catheterization, although the total numbers of women affected by CSX are unknown. Varying clinical definitions and the lack of large scale epidemiologic studies focusing on this illness have resulted in limited knowledge about its risk factors, although there appears to be an association with black race, estrogen deficiency, and insulin resistance. Contrary to prior beliefs about the benign nature of this entity, these women suffer considerable morbidity with costly economic implications that approach the lifetime costs of healthcare utilization for those with obstructive coronary disease. Two prevailing hypotheses have emerged to explain CSX: the ischemic hypothesis detailing abnormal coronary microvascular function and the non-ischemic hypothesis describing altered pain perception and myocardial hypersensitivity. Treatment strategies have focused on both of these pathways with the main goal of improving symptoms. Beta blockers provide the most convincing evidence for benefit, with other antianginals having secondary roles. Other promising pharmacologic therapies include xanthine derivatives, estrogen replacement therapy, ACE inhibitors, and statin medications, among other emerging treatment options. Neurostimulation and lifestyle factors including exercise can also be beneficial in reducing symptoms. However, managing patients with CSX can be frustrating for both patients and physicians, as there is a lack of data regarding an optimal treatment algorithm including few large-scale randomized controlled trials to clarify effective therapies.Current Cardiology Reviews 02/2010; 6(1):71-81.
Article: Role of the vascular endothelium in patients with angina pectoris or acute myocardial infarction with normal coronary arteries.[show abstract] [hide abstract]
ABSTRACT: Chest pain with normal coronary angiograms is a relatively common syndrome. The mode of presentation of this syndrome includes patients with syndrome X and patients with an acute myocardial infarction and angiographically normal coronary arteries. Different mechanisms have been proposed to elucidate the exact cause and to explain the various clinical presentations in these patients. Abnormalities of pain perception and the presence of oesophageal dysmotility have all been reported in patients with syndrome X. In situ thrombosis or embolization with subsequent clot lysis and recanalization, coronary artery spasm, cocaine abuse, and viral myocarditis have been described as potential mechanisms responsible for an acute myocardial infarction in patients with angiographically normal coronary arteries. Recent data suggest that both microvascular and epicardial endothelial dysfunction may play an important role in the pathophysiological mechanism of the syndrome of stable angina or acute myocardial infarction with normal coronary arteries.Postgraduate Medical Journal 02/2000; 76(891):16-21. · 1.94 Impact Factor