Endothelin-1-induced impairment of endothelium-dependent relaxation in aortas isolated from controls and diabetic rats

An accumulating body of evidence indicates that an increased endothelin-1 level is related to endothelial dysfunction in cardiovascular diseases. In this study, we tested whether prolonged treatment of aortas with endothelin-1 induces endothelial dysfunction. When isolated aortas from control rats were cultured with endothelin-1, at levels above the plasma concentration, the acetylcholine-induced endothelium-dependent relaxation was significantly decreased (as compared with endothelin-1-nontreatment). This endothelin-1-induced endothelial dysfunction was more marked in aortas obtained from rats with streptozotocin-induced diabetes than in those from the controls. The endothelin-1- induced attenuation was very strongly suppressed by co-incubation with J-104132, endothelin receptor A/B antagonist, or polyethylene-glycolated superoxide dismutase, a cell-permeant superoxide anion scavenger or LY294002, phosphoinositide 3-kinase inhibitor. These results indicate that endothelin-1 can induce endothelial dysfunction, and that this may be related to superoxide generation and to PI3-kinase activity.     

Review of arrythmias related to acute myocardial infarction and its treatment

Because reperfusion therapy for AMI has been widely performed, complicated fatal ventricular arrythmias related to AMI has been dramatically decreased. However, there still remain the incidence of fetal arrhythmias such as ventricular fibrillation(VF), ventricular tachycardia(VT) at the early phase in occurrence of AMI. Besides spreading bolus intravenous administration of mutant-tPA, Bystander CPR, Public access defibrillation (PAD), and setting of automated external defibrillators(AED) in the public facilities are actually required to reduce the mortality of AMI. In this article, we reviewed that arrhythmias associated with AMI and strategy for treatments of complicated arrhythmias in the clinical settings.     

Involvement of inflammation in acute coronary syndromes assessed by levels of high-sensitivity C-reactive protein, matrix metalloproteinase-9 and soluble vascular-cell adhesion molecule-1

OBJECTIVES: Inflammation is important in the development of atherosclerosis. Matrix metalloproteinases (MMPs) and interferon-gamma which participate in collagen degradation are pathological factors in plaque vulnerability as an important mechanism underlying acute coronary syndrome. This study investigated whether inflammation is related to the onset of acute coronary syndrome. METHODS: This study included 56 patients with acute coronary syndrome (ACS group), 104 patients with chronic coronary artery disease (S group), and 38 control subjects with no evidence of ischemic heart disease (C group). High-sensitivity C-reactive protein (hs-CRP), MMP-9, and interferon-gamma were measured in peripheral blood samples. Soluble adhesion molecules (VCAM-1, ICAM-1) were also measured as inflammatory markers. RESULTS: The hs-CRP level was significantly higher in the ACS group (44.5 mg/l) than in the S group (2.1 mg/l) and the C group (0.6 mg/l) (p < 0.0001). The MMP-9 level was also significantly higher in the ACS group (333.8 ng/ml) than in the S group (110.8 ng/ml) and the C group (72.0 ng/ml) (p < 0.0001). The VCAM-1 level was significantly higher in the ACS group (506.5 ng/ml) than in the C group (448.8 ng/ml) (p < 0.05). The ICAM-1 level and the interferon-gamma level did not differ between the groups. There was a significant positive correlation between the level of hs-CRP and the level of the collagen degradation product MMP-9 (r = 0.52) in all subjects. CONCLUSIONS: These results suggest that plaque destabilized by MMP-9 produced in response to inflammation participates in the mechanism of acute coronary syndrome.     

Study of active substances involved in skin dysfunction induced by crowding stress. I. Effect of crowding and isolation on some physiological variables,skin function and skin blood perfusion in hairless mice

The effects of five levels of population density on various organs, the neuroendocrine system, skin function, skin blood perfusion, and blood parameters were studied in the hairless mouse. Skin barrier recovery was evaluated by measuring transepidermal water loss after tape stripping. Blood perfusion was measured by means of a laser Doppler imaging technique. The effect of a parasympathetic nerve stimulator, carpronium chloride, on skin function in the crowded animal model was also examined. A 7 d crowding (10, 15, 20 mice/cage) significantly increased the levels of corticosterone, catecholamines (norepinephrine, epinephrine and dopamine), glucose and serum lactate dehydrogenase activity in circulating blood, induced atrophy of kidney, ovary and thymus and hypertrophy of adrenal glands, and decreased body weight gain in comparison with the control (5 mice/cage). Crowding also increased epidermal thickness and epidermal proliferative activity, and decreased corneocyte size, rate of barrier recovery and skin blood perfusion. Most of these changes became more marked with increasing population density and/or longer exposure to a crowded environment. Isolation (1 mouse/cage) increased the level of norepinephrine and rate of skin blood perfusion, and significantly delayed barrier recovery. Repeated topical applications of carpronium chloride for 7 d improved the changes in skin blood perfusion, barrier recovery, kidney and ovary, and epidermal morphology induced by crowding. The crowded animal model could be useful for quantifying objectively the influence of crowded environment-induced stress on cutaneous function and blood perfusion.     

Effects of antisense peptide nucleic acid to platelet-derived growth factor A-chain on growth of vascular smooth muscle cells

To investigate antisense peptide nucleic acid (PNA) as a gene therapy for the arterial proliferative diseases, the authors designed and examined the effects of an antisense PNA targeting platelet-derived growth factor (PDGF) A-chain on expression of PDGF A-chain and growth of vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats. A 15-mer antisense PNA complementary to the initiation codon of rat and human PDGF A-chain mRNA was synthesized and purified by high-performance liquid chromatography. Gel-shift assay and biomolecular interaction analysis (BIAcore) revealed that the antisense PNA bound weakly to the target RNA, whereas it bound strongly to the target DNA. Fluorescein-isothiocyanate-labeled antisense PNA to PDGF A-chain was taken up slowly and maintained in VSMCs for a prolonged period of time. Antisense PNA inhibited expression of PDGF A-chain mRNA and protein as well as DNA synthesis in VSMCs in a dose-independent manner. Inhibition of DNA synthesis by the antisense PNA was greater than that by the antisense DNA at a low concentration (0.5 micromol/L). These results suggest that antisense PNA to PDGF A-chain will be used as a gene therapy for vascular proliferative diseases such as hypertensive vascular diseases, restenosis of coronary arteries after angioplasty, and atherosclerosis.