Guillermo Aldama

Markers of inflammation and multiple complex stenoses (pancoronary plaque vulnerability) in patients with non-ST segment elevation acute coronary syndromes

Objective: To assess the relation between markers of inflammation and the presence of multiple vulnerable plaques in patients with non-ST segment elevation acute coronary syndromes. Design: Prospective cohort study of 55 patients with non-ST segment elevation acute coronary syndromes and angiographically documented coronary disease. Blood samples were obtained at study entry for the assessment of high sensitivity C reactive protein (CRP), neopterin, and neutrophil count. Coronary stenoses were assessed by quantitative computerised angiography and classified as “complex” (irregular borders, ulceration, or filling defects) or “smooth” (absence of complex features). Extent of disease was also assessed by a validated angiographic score. Results: Neutrophil count (r  =  0.36, p  =  0.007), CRP concentration (r  =  0.33, p  =  0.02), and neopterin concentration (r  =  0.45, p < 0.001) correlated with the number of complex stenoses. Patients with multiple (three or more) complex stenoses, but not patients with multiple smooth lesions, had a higher neutrophil count (5.9 (1.4) × 109/l v 4.8 (1.4) × 109/l, p  =  0.02), CRP concentration (log transformed) (1.08 (0.63) v 0.6 (0.6), p  =  0.03), and neopterin concentration (log transformed) (0.94 (0.18) v 0.79 (0.15), p  =  0.002). Multiple regression analysis showed that neopterin concentration (B  =  4.8, 95% confidence interval (CI) 1.9 to 7.7, p  =  0.002) and extent of coronary artery disease (B  =  0.6, 95% CI 0.03 to 1.2, p  =  0.04) were independently associated with the number of complex stenoses. Conclusions: Acute inflammatory markers such as high neutrophil count, CRP concentration, and neopterin concentration correlate with the presence of multiple angiographically complex coronary stenoses. Neopterin concentration was a stronger predictor of multiple complex plaques than were neutrophil count and CRP concentration. These findings suggest that a relation exists between inflammation and pancoronary plaque vulnerability.

Cardiac Syndrome X

Patients with cardiac syndrome X (typical chest pain and normal coronary arteriograms) represent a heterogeneous syndrome, which encompasses different pathogenic mechanisms. Although symptoms in most patients with cardiac syndrome X are non-cardiac, a sizable proportion of them have angina pectoris due to transient myocardial ischemia. Thus radionuclide myocardial perfusion defects, coronary sinus oxygen saturation abnormalities and pH changes, myocardial lactate production and stress-induced alterations of cardiac high energy phosphate suggest an ischemic origin of symptoms in at least a proportion of patients with cardiac syndrome X. Microvascular abnormalities, caused by endothelial dysfunction, appear to be responsible for myocardial ischemia in patients with cardiac syndrome X. Endothelial dysfunction is likely to be multifactorial in these patients and it is conceivable that risk factors such as hypertension, hypercholesterolemia, diabetes mellitus and smoking can contribute to its development. Most patients with cardiac syndrome X are postmenopausal women and estrogen deficiency has been therefore proposed as a pathogenic factor in female patients. Additional factors such as abnormal pain perception may contribute to the pathogenesis of chest pain in patients with angina pectoris and normal coronary angiograms. Although prognosis is good regarding survival, patients with cardiac syndrome X have an impaired quality of life. Management of this syndrome represents a major challenge to the treating physician. Understanding the mechanism underlying the condition is of vital importance for patient management. Thus diagnostic tests should aim at identifying the cause of the symptoms in the individual patient, i.e. myocardial ischemia, increased pain perception, abnormalities of adrenergic tone, non-cardiac mechanisms, etc. Moreover, it is important to bear in mind that treatment of cardiac syndrome X should be mainly directed towards improving quality of life, as prognosis is usually good in these patients. Conventional antianginal agents such nitrates, calcium channel antagonists, β-adrenoceptor antagonists and nicorandil are effective particularly in patients in whom chest pain and ECG changes are clearly suggestive of myocardial ischemia and in those with objective documentation of ischemia. Angiotensin-converting enzyme inhibitors have been shown to be useful in syndrome X patients with increased adrenergic tone, borderline systemic hypertension, and those with documented endothelial dysfunction. Analgesic interventions of different sorts have been proposed based on the hypothesis that somatic and visceral perception of pain is altered in cardiac syndrome X patients. Pharmacological agents such as imipramine and aminophylline, and neural electrical stimulation techniques have been assessed in recent years with encouraging results. Psychological treatment, particularly cognitive therapy, appears to be useful in defined patient subsets. Relaxation techniques such as transcendental meditation have been successfully used in small studies and shown to improve not only chest pain but also exercise-induced ST segment changes. Reports indicate that these techniques improve quality of life.

Analysis of Different Routes of Administration of Heterologous 5-Azacytidine-Treated Mesenchymal Stem Cells in a Porcine Model of Myocardial Infarction

Stem cell therapy constitutes an exciting, powerful therapy to repair the heart. Nevertheless, there are numerous doubts about the best route of stem cell administration to achieve implantation into the injured myocardium. Development of a preclinical, large animal model may be useful to obtain a better approach to clinical situations. The aim of this work was to study the effectiveness of various routes of heterologous bone marrow mesenchymal stem cell (MSCs) administration in a porcine model of myocardial infarction. MSC treated with 5-azacytidine were stained with a fluorescent compound (DiO) before their administration to previously infarcted pigs via 3 routes: intracoronary (IC), intramyocardial (IM), or endocardial (EC; n = 5 each group). Healthy, noninfarcted animals were used as a control group. At 30 days after delivery, hearts were divided into 12 parts: infarcted zone (1-6), right-left atria, interatrial and interventricular septa, and right-left ventricles. In each zone we looked for and quantified, injected fluorescence-stained cells. In the animals in which presence of DiO-stained cells was detected, cells were located preferentially in the infarcted zone and not in the atria, ventricles, or septa. Comparing various administration routes, the mean number of engrafted cells within the infarct zone was significantly greater after IC infusion than either IM or EC injection. Fluorescent cells were not observed in healthy zones of the myocardium or in healthy animals.

A MicroRNA-Transcription Factor Blueprint for Early Atrial Arrhythmogenic Remodeling

Spontaneous self-terminating atrial fibrillation (AF) is one of the most common heart rhythm disorders, yet the regulatory molecular mechanisms underlying this syndrome are rather unclear. MicroRNA (miRNA) transcriptome and expression of candidate transcription factors (TFs) with potential roles in arrhythmogenesis, such as Pitx2, Tbx5, and myocardin (Myocd), were analyzed by microarray, qRT-PCR, and Western blotting in left atrial (LA) samples from pigs with transitory AF established by right atrial tachypacing. Induced ectopic tachyarrhythmia caused rapid and substantial miRNA remodeling associated with a marked downregulation of Pitx2, Tbx5, and Myocd expression in atrial myocardium. The downregulation of Pitx2, Tbx5, and Myocd was inversely correlated with upregulation of the corresponding targeting miRNAs (miR-21, miR-10a/10b, and miR-1, resp.) in the LA of paced animals. Through in vitro transient transfections of HL-1 atrial myocytes, we further showed that upregulation of miR-21 did result in downregulation of Pitx2 in cardiomyocyte background. The results suggest that immediate-early miRNA remodeling coupled with deregulation of TF expression underlies the onset of AF.

Gene expression profiles following intracoronary injection of mesenchymal stromal cells using a porcine model of chronic myocardial infarction

BACKGROUND AIMS We evaluated the therapeutic potential of injection of in vitro differentiated bone marrow mesenchymal stromal cells (MSC) using a swine model. METHODS AND RESULTS Myocardial infarction was induced by coronary occlusion. Three groups (n = 5 each) were analyzed: one group received an injection of 17.8 ± 9.3 × 10(6) 5-azacytidine-treated allogeneic MSC 1 month after infarction; a placebo group received an injection of medium; and controls were kept untreated. After 4 weeks, heart samples were taken from three infarcted areas, interventricular septa, ventricles and atria. Gene expression profiles of genes related to contractility (Serca2a), fibrosis (Col1a1), cardiomyogenesis (Mef2c, Gata4 and Nkx2.5) and mobilization of stem cells (Sdf1, Cxcr4 and c-kit) were compared by quantitative real-time PCR (qRT-PCR). Gene expression profiles varied in different heart areas. Thus Serca2a expression was reduced in infarcted groups in all heart regions except for the left ventricles, where Col1a1 was overexpressed. The expression of genes related to cardiomyogenesis decreased in the infarcted zones and left atria compared with healthy hearts. Interestingly, increased expression of Cxcr4 was detected in infarcted regions of MSC-treated pigs compared with the placebo group. CONCLUSIONS Infarction induced changes in expression of genes involved in various biologic processes. Genes involved in cardiomyogenesis were downregulated in the left atrium. The intracoronary injection of MSC resulted in localized changes in the expression of Cxcr4.

Comparison of Gene Expression Profiles in a Porcine Infarct Model After Intracoronary, Transthoracic, or Transendocardiac Injection of Heterologous Bone Marrow Mesenchymal Cells

An in vivo porcine model of myocardial infarction was developed with the aim of comparing the effectiveness for cardiac repair of intracoronary, transthoracic, or transendocardial delivery strategies for bone marrow mesenchymal stem cells (BMMSC) using an analysis of expression levels of transcripts related to various cellular processes at 8 heart regions using quantitative reverse transcriptase polymerase chain reaction. We observed significant rises in cardiomyogenic markers Mef2C, Gata4 and Nkx2.5, and contractibility marker Serca2A at infarcted regions for cell-treated pigs. We also observed differences in Sdf1 expression related to the organ stress response between delivery strategies. Unexpectedly, increased expression of Col1A1 was detected in 2 cell-treated groups at various heart regions. Our results suggest improvements in both contractility and cardiomyogenic capability of damaged tissue after BMMSC injection, but also warned us about the relevance of the chosen delivery strategy and potential undesired effects like increasing fibrosis after treatment.

Coronary-subclavian steal syndrome.

A58-year-old man was admitted with exertional angina. Two years previously, he underwent myocardial revascularization consisting of a left internal mammary artery (LIMA) graft to the left anterior descending coronary artery, and a right internal mammary artery graft from the LIMA to the ramus intermedius and to a left posterolateral branch. His physical examination was remarkable for the presence of a left supraclavicular bruit, and weak left radial and brachial pulses, with a significant discrepancy in blood pressure between the right (120/80 mmHg) and left (80/45 mmHg) arms. Contrast injection into the left main coronary artery (Figure 1) showed no evidence of progression of native coronary atherosclerotic disease, but did demonstrate a striking retrograde flow from the coronary tree through the grafts, which were all patent. A left subclavian artery angiography was subsequently performed, revealing a high-grade subclavian stenosis proximal to the origin of the LIMA (Figure 2A). The patient was successfully treated with subclavian balloon angioplasty and stent placement (Figure 2B), and has remained asymptomatic after a two-year follow-up. Figure 1) Left coronary angiography showing retrograde flow from the coronary tree through the mammary artery bypass grafts. LIMA Left internal mammary artery; RIMA Right internal mammary artery Figure 2) Subclavian artery angiography before (A) and after (B) stent placement. LIMA Left internal mammary artery In patients with mammary-coronary bypass grafts, the presence of a subclavian artery stenosis proximal to the internal mammary artery may result in a condition termed ‘coronary-subclavian steal syndrome’, which may cause a reversal of flow through the grafts from the coronary to the subclavian circulation, resulting in myocardial ischemia (1,2). Surgical therapy (carotid-subclavian or carotid-axillary bypass) was considered to be the procedure of choice in the past, but presently, percutaneous angioplasty and stenting of the subclavian artery is the most widely recommended therapeutic option.