[Effect of Cilazapril on endothelial cell function and fibrinolysis system in the canine atrial fibrillation models].

OBJECTIVE: To investigate the effect of cilazapril on endothelial cell function and fibrinolysis system in the canine atrial fibrillation (AF) models. METHODS: All canines were divided into three groups: (1) Control group, without atrial pacing; (2) Atrial pacing group, in which atrial fibrillation was established by rapid atrial pacing at 400 bpm for 6 weeks; (3) Atrial pacing together with cilazapril group, in which cilazapril was given before and after atrial pacing. Nitric oxide (NO) of atrial endocardium was measured with NO-specific microelectrode. The expression of plasminogen activator inhibitor-1 (PAI-1) and tissue-type plasminogen activator (tPA) protein in atrium was determined by Western Blot analysis and immunohistochemical staining. Plasma levels of von Willebrand Factor (vWF), PAI-1 and tPA were analyzed by enzyme-linked immunoadsorbent assay. RESULTS: NO production from atrial endocardium was significantly increased in atrial pacing together with cilazapril group than atrial pacing group [(42.6 +/- 9.9) nmol/L vs (23.4 +/- 5.8) nmol/L, P < 0.05], whereas the plasma levels of vWF were decreased [(75.4 +/- 12.8)% vs (125.9 +/- 20.6)%, P < 0.05]. Compared to controls, the expression of atrium tPA protein in atrial pacing together with cilazapril group was significantly upregulated (4052 +/- 857 vs 1936 +/- 421, P < 0.05) and PAI-1 protein was downregulated (2487 +/- 542 vs 3164 +/- 827, P < 0.05). Cilazapril also significantly increased tPA antigen and decreased PAI-1 antigen in plasma. CONCLUSION: Cilazapril can favorably improve endothelial function and resume the balance of fibrinolysis system in AF, which might be of beneficial to hypercoagulated state in AF.

In vitro effects of helium-neon laser irradiation on human blood: blood viscosity and deformability of erythrocytes.

OBJECTIVE: The purpose of this study was to investigate the in vitro effects of He-Ne laser irradiation on some rheological factors of human blood, such as blood viscosity, erythrocyte deformability, and sedimentation rate. BACKGROUND DATA: The intravascular irradiation of low power laser has been applied in pre-clinical and clinical to treat various pathological processes. However, the mechanism is not fully understood so far. Especially the interaction and related mechanism between the laser and blood are unclear. In this work, by measuring the change of the main rheological factors after laser irradiation, the interaction and mechanism were explored. METHODS: A30-mW He-Ne laser was used for irradiation with a 4-5-mm-diameter beam spot on blood samples, with a fluence rate of about 150 mW/cm.(2) The irradiation time was 60 min, so the total dose of irradiation was 540 J/cm.(2) The pathological samples of blood were obtained from patients (volunteers), and each sample was divided into two tubes for irradiation and control. The blood viscosity, erythrocyte deformability, and sedimentation rate were measured after laser irradiation and compared with un-irradiated control. The blood samples with poor erythrocyte deformability were prepared by adding Ca(2+) to the normal erythrocytes of a healthy person for investigating the laser effect on erythrocyte deformability further. RESULTS: Laser irradiation reduced the erythrocyte sedimentation rate of blood samples, which had a hyper-sedimentation rate originally. The blood viscosity of samples in hyper-values was lowered by laser irradiation in all shear rates measured (10-110 S(-1)), with a relative variation of approximately 10%. The deformability of erythrocytes from pathological samples and Ca(2+)-treated samples was improved after laser irradiation. CONCLUSIONS: The positive effects of laser irradiation on improving the rheological properties of blood were demonstrated in vitro.

Influence of shearing Stress to the Expression of Endothelin by Vascular Endothelial Cells.

Using radioimmunoassay and Northern blot, the differences in endothelin and its mRNA expression were studied for cultured cerebral micro-vascular endothelial cells (from WKY and SHR rats) which exposed to flow shear stress at 0, 0.5, 1, 2 Pa for 24 h. The results showed that the endothelin and its mRNA expression of endothelial cells from both WKY and SHR rats proportionally increased according to the shear stress values at 0, 0.5 and 1 Pa, at 2 Pa, however the endothelin and its mRNA expression did not increase further. When comparing both rat systems, the SHR's levels of endothelin and its mRNA expression were higher than WKY's. The results indicated that the levels of endothelin and its mRNA expression were proportional to shear stress in 0-1 Pa in WKY and SHR rat systems and the levels of endothelin and its mRNA of SHR system were higher than those of WKY's. Our results indicate that the vascular wall in SHR system may be more contractile, less relaxative, with lower remodeling ability and thus more easily to mediate atherosclerosis.