The endothelial nitric oxide synthase T-786c mutation, a treatable etiology of Prinzmetal's angina.

We assessed to what degree the endothelial nitric oxide synthase (eNOS) T-786C polymorphism, leading to reduced nitric oxide (NO) production-coronary artery spasm, was reversibly associated with Prinzmetal's variant angina (PVA). ENOS T-786C PCR analyses were done in 19 women, 8 men, 26 Caucasian, 1 African-American, median age 53, with well-documented PVA and in 72 healthy controls who did not differ by race or gender. Of the 27 cases, 7 (26%) were homozygous for wild-type normal eNOS (CC), 13 (48%) were T-786C heterozygotes (CT), and 7 (26%) were T-786C homozygotes (TT) vs controls, 44 (61%) CC, 27 (38%) TC, and 1 (1%) TT, P < 0.0001. The mutant eNOS T-786C allele frequency in PVA patients was 27/54 (50%) vs 29/144 (20%) in controls, P < 0.0001. On oral L-arginine (9.2 g/d) to increase production of NO for a median of 4.7 months in 16 PVA patients with symptomatic angina despite conventional nitrate-calcium channel blockers, using the Seattle Angina Questionnaire, satisfaction with symptom remission rose (median) from 50% to 100% (P = 0.004), satisfaction with angina frequency reduction rose from 65% to 80% (P = 0.02), satisfaction with treatment for symptoms rose from 38% to 88% (P = 0.001), and perception of overall life status rose from 25 to 71% (P = 0.0002). On L-arginine (median 4.7 months), in 20 patients, none had worsening of angina, and of 7 patients whose angina totally resolved, eNOS T-786C homozygosity was over-represented, P = 0 .04. The eNOS T-786C mutation appears to be a reversible etiology of PVA in patients whose angina may be ameliorated by L-arginine.

Vasospastic angina and microvascular angina are differentially influenced by PON1 A632G polymorphism in the Japanese.

BACKGROUND: Ethnicity and smoking are well-known risk factors for the pathogenesis of coronary vasospasm. Oxidative stress induced by smoking plays a crucial role in coronary vasospasm, but is not enough to account for the pathogenesis of coronary vasospasm, indicating that genetic factors are strongly involved. METHODS AND RESULTS: The study group comprised 162 vasospastic angina patients (VSAs), 61 microvascular angina patients (MVAs) and 61 non-responders (NRs) diagnosed by acetylcholine provocation test. Four polymorphisms of the oxidative stress related genes, cytochrome b-245, alpha polypeptide gene (CYBA) C242T and A640G, paraoxonase 1 gene (PON1) A632G, phospholipase A2 group VII gene (PLA2G7) G994T were genotyped. Allele frequency of PON1 632-G was significantly higher in both the VSA with dominant fashion and the MVA with recessive fashion compared with NR. This association was strongly influenced by gender in the MVA only. There were no significant associations between the other polymorphisms and coronary vasospasm. In addition, the allele frequency of PON1 632-G in the Japanese was higher than in Caucasians. CONCLUSIONS: There was a significant association between PON1 A632G polymorphism and MVA as well as VSA, but the impact of this on VSA and MVA is different in the Japanese.

Intracellular neutrophil myeloperoxidase is reduced in unstable angina and acute myocardial infarction, but its reduction is not related to ischemia.

OBJECTIVES: This study sought to assess neutrophil activation in acute coronary syndromes and its relation to ischemic episodes. BACKGROUND: Neutrophil activation has been reported in unstable angina and acute myocardial infarction; however, it is not clear whether it is related exclusively to ischemia-reperfusion injury. METHODS: We measured the index of intracellular myeloperoxidase in 1) patients with unstable angina, myocardial infarction, variant angina and chronic stable angina and in normal subjects (protocol A); and 2) in patients with unstable angina and acute myocardial infarction during the first 4 days of the hospital period (protocol B). To assess whether neutrophil activation was triggered by ischemia, the myeloperoxidase intracellular index was analyzed before and after spontaneous ischemic episodes and before and after ischemia induced by an exercise stress test in 10 patients with chronic stable angina. In 11 patients with unstable angina, we also compared values of the myeloperoxidase intracellular index at entry with those after waning of symptoms. RESULTS: In protocol A, the myeloperoxidase intracellular index was significantly reduced in patients with unstable angina and acute myocardial infarction compared with patients with stable and variant angina and normal subjects (p < 0.01). In protocol B, the myeloperoxidase intracellular index did not change over time in patients with unstable angina and myocardial infarction. However, in 11 patients with waning symptoms, the myeloperoxidase intracellular index was significantly higher afer symptoms had waned (p < 0.05). In patients with unstable angina, 23 ischemic episodes were studied; no changes in the myeloperoxidase intracellular index were observed. In 10 patients with chronic stable angina and positive exercise stress test results, no significant differences in the myeloperoxidase intracellular index were observed after stress-induced ischemia. CONCLUSIONS: Our study confirms that neutrophils are activated in acute coronary syndromes but suggests that their activation may not be only secondary to ischemia-reperfusion injury.

Circulating cardiac myosin light chains in patients with angina at rest: identification of a high risk subgroup.

To detect myocardial cell damage, serum samples of 42 consecutive patients with angina at rest were screened for cardiac myosin light chains, which were detected in 22 patients (52%). In 17 of these patients there was a persistent release of myosin light chains lasting until the 4th hospital day, whereas in 7 patients myosin light chains were only detectable during the initial 24 h after admission. The presence of myosin light chains correlated with signs of ischemia in the electrocardiogram (ECG) (p less than 0.05) and with the extent of coronary artery narrowing (p less than 0.05). Cardiac myosin light chains were elevated in serum only if there was a greater than or equal to 75% diameter narrowing in at least one major vessel. In all five patients who developed transmural myocardial infarction during the course of their hospital stay, myosin light chains were detectable greater than or equal to 28 h before the diagnosis of myocardial infarction could be established by ECG criteria and conventional serum enzymes. Thus the detection of circulating cardiac myosin light chains enables one to identify a subgroup of patients with angina at rest having more severe coronary artery disease with a worse outcome.

Selective thromboxane A2 synthetase inhibition in vasospastic angina pectoris.

To investigate whether thromboxane A2 is responsible for the initiation of vasospastic angina pectoris, thromboxane B2 levels were measured in the great cardiac vein and the arterial blood of 12 patients with clinically and angiographically proved vasospastic angina and therapeutic trials were performed with selective thromboxane A2 synthetase inhibitor OKY-046, an imidazole derivative. During ergonovine-provoked (11 cases) and spontaneous (1 case) anginal attacks, great cardiac vein thromboxane B2 increased from 121 +/- 27 to 430 +/- 382 pg/ml (p less than 0.05, n = 12), arterial thromboxane B2 increased from 93 +/- 18 to 122 +/- 33 pg/ml (NS, n = 12) and thromboxane B2 production increased from 3.18 +/- 1.88 to 25.16 +/- 22.32 ng/min (p less than 0.05, n = 6). Subsequently, OKY-046, 400 mg/day orally, was administered to 7 of the 12 patients, while a continuous electrocardiogram was recorded on a dual channel Holter monitor during a 3 day placebo period and the 3 day OKY-046 regimen. Although peripheral plasma thromboxane B2 levels decreased significantly from 98 +/- 15 to 12 +/- 8 and 28 +/- 10 pg/ml (1 and 6 hours after ingestion, respectively) (p less than 0.05 for both), 6-keto-prostaglandin F1 alpha production in serum increased significantly from 0.48 +/- 0.22 to 2.3 +/- 0.72 (1 hour) and 1.8 +/- 0.46 ng/ml (6 hours) (p less than 0.05 for both) during OKY-046 administration.(ABSTRACT TRUNCATED AT 250 WORDS)