Evaluation of the antithrombotic activity of Zhi-Xiong Capsules, a Traditional Chinese Medicinal formula, via the pathway of anti-coagulation, anti-platelet activation and anti-fibrinolysis.

Zhi-Xiong Capsules (ZXC) involving Hirudo, Ligusticum chuanxiong, Salvia miltiorrhiza, Leonurus artemisia, and Pueraria lobata, is an empirical prescription used in Chinese clinics applied for treating cerebral arteriosclerosis and blood-stasis in clinic. However, the mechanism of its antithrombotic activity has not been investigated until now. The present study was designed to investigate its antithrombotic effects, the mechanism of ZXC on anti-thrombus action and to identify the main chemical composition of ZXC using HPLC-DAD-ESI-IT-TOF-MS. Two animal models were used to evaluate the antithrombotic effect of ZXC, the arterial thrombosis model and a venous thrombosis model. ZXC prolonged the plasma recalcification time (PRT), the activated partial thromboplastin time (APTT), the thrombin time (TT) and the prothrombin time (PT) and clearly reduced the content of fibrinogen (FIB) obviously in the arterial thrombosis model. Furthermore, it markedly suppressed the level of TXB2 and up-regulated the level of 6-keto-PGF1a. In addition, it significantly up-regulated the level of t-PA and down-regulated the level of PAI-1 (p < 0.05). These results revealed that ZXC played a vital role in the prevention of thrombosis through interacting with multiple targets, including inhibition of coagulation and platelet aggregation and increasing thrombolysis. A total of 23 compounds were identified as the main components of ZXC by HPLC-DAD-ESI-IT TOF-MS.

Characterization of 11-dehydro-thromboxane B2 recombinant antibody obtained by phage display technology.

Recombinant monoclonal antibodies specific for 11-dehydro-thromboxane B(2) (11D-TX) were isolated from the combinatorial libraries on a pComb3 phage-display vector using a magnetic cell sorting (MACS) system. The libraries were constructed from repertories of light and heavy-chains derived from the total RNA of 11D-TX conjugated keyhole limpet haemocyanin-immunized mice. Biotinylation of 11D-TX conjugated bovine serum albumin (BSA) was performed through free thiol groups on BSA using 1-biotinamido-4-[4'-(maleimidomethyl) cyclohexanecarboxamido] butane (Biotin-BMCC). Affinity bio-panning was performed to enrich the phage display libraries against biotinylated 11D-TX conjugated BSA with the MACS system. Results indicated that the selected anti-11D-TX Fab fragments expressed by E. coli exhibited a five-fold higher affinity for BSA conjugated 11D-TX compared to BSA alone and little specificity to other related compounds as determined by the binding assay and inhibition enzyme-linked immunosorbent assay (ELISA). This is the first report of an antibody against prostaglandin produced by phage display technology and also determination of the DNA sequence of this antibody. The MACS system was shown to be a simpler and more efficient method of panning than the conventional ELISA procedure. According to our results, we concluded that the phage display technique combined with the MACS system allowed the selection of the antibody with high affinity and some specificity.

Influences of dietary omega-3 polyunsaturated fatty acids on the recovery of cardiac and renal functions after preservation in hyperlipidemic rats.

BACKGROUND: The effects of a soybean oil diet and a high-cholesterol oil (HC) diet, and an HC diet with eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) supplementation, on basal and postpreservative cardiac function of the hearts and on postpreservative renal function of the kidneys from older rats were examined. METHODS: Groups 1 through 4 of 100-week-old rats were fed either soybean oil, HC, HC with EPA, or HC with DHA, respectively, for 12 weeks. Blood was collected for analysis of plasma fatty acids, and the heart and left kidney were removed from the rat. In experiment 1, the heart was perfused on a Langendorff apparatus. After evaluation of the cardiac function of each rat, the heart was stored in histidine-tryptophan-ketoglutarate solution for 8 hr at 4 degrees C. The heart was reperfused and the recovery of cardiac function was evaluated. The coronary perfusate during reperfusion was collected to measure 6-keto prostaglandin F1alpha and thromboxane B2. Coronary flow (CF) perfused with Krebs-Henseleit bicarbonate (KHB) solution containing 5-hydroxytryptamine (5-HT) and nitroglycerin were evaluated in the Langendorff mode with atrial pacing (330 beats/min). In experiment 2, the excised left kidney was immediately flushed and preserved with University of Wisconsin solution for 8 hr at 4 degrees C. The kidney was then reperfused with KHB solution and renal function was evaluated. RESULTS: The plasma and cardiac EPA levels in group 3 were significantly higher than the levels found in the other groups. The plasma and cardiac ratios of EPA to arachidonic acid were significantly higher in groups 3 and 4 than in groups 1 and 2. There were no significant differences in basal cardiac function among any of the diet-fed rats. The percentage values of the recovery of aortic flow, cardiac output (CO), and left ventricular max dp/dt in group 3 and CO in group 4 were significantly higher than in group 2. In addition, the recovery of CF in group 3 tended to be higher than in group 2 (P=0.07). The percentage values of the recovery of aortic flow, CF, CO, and left ventricular max dp/dt in group 1 were significantly lower than in the other dietary groups. CF reperfused with KHB solution containing 5-HT was significantly higher in group 3 than in groups 1 and 2. CF reperfused with KHB solution containing 5-HT was significantly higher in group 4 than in group 1. CF reperfused with KHB solution containing nitroglycerin in group 3 tended to be higher than in groups 1 and 2 (P=0.07). The thromboxame B2 concentrations in the coronary perfusate during reperfusion in groups 3 and 4 were significantly lower than in groups 1 and 2. Fractional sodium reabsorption in group 3 was significantly higher than in group 2. Inulin clearance in groups 3 and 4 was significantly higher than in group 1. The postpreservative urinary flow in group 3 was significantly higher than in groups 1 and 2. The urinary flow was significantly higher in group 4 than in group 1. CONCLUSIONS: These results suggest that EPA administration may attenuate preservation and reperfusion injury and improve the recovery of cardiac and renal functions in hyperlipidemic and older rats. DHA administration may also show beneficial effects on kidney preservation in hyperlipidemic rats.

Arachidonic acid metabolites modulate rat hypothalamic corticotropin-releasing hormone secretion in vitro.

Arachidonic acid metabolites have been shown to modulate the secretion of various hormones, including luteinizing hormone, growth hormone and adrenocorticotropin. In this paper we describe the effect of a series of eicosanoids on hypothalamic secretion of corticotropin-releasing hormone (CRH) in vitro. Explanted rat hypothalami in culture were exposed to prostaglandins (PG) F2 alpha or E2, thromboxane (TX) B2, the TXA2 receptor agonist U-49,619 and leukotrienes (LT) B4, C4 and D4 at concentrations ranging from 10(-15) to 10(-5) M. PGE2, LTD4 and TXB2 did not alter hypothalamic CRH secretion. On the other hand, the remaining eicosanoids tested induced a significant increase of hypothalamic CRH secretion (p less than 0.05). The concentration of 10(-11) M dexamethasone inhibited the effect of stimulatory eicosanoids on CRH secretion. The CRH response to U-49,619 was completely prevented by the TXA2 receptor antagonist SQ-29,548. The latter also inhibited serotonin (5-HT)-, acetylcholine (ACh)- and PGF2 alpha-induced CRH release. Indomethacin was capable of blocking the secretion of CRH induced by 5-HT and ACh. In addition, PGE2 inhibited the increase of CRH secretion induced by PGF2 alpha, 5-HT and ACh. These findings suggest that eicosanoids may be involved in the regulation of hypothalamic CRH secretion, either as autocrine/paracrine or as endocrine factors.

Inhibitory effects of a novel platelet activating factor (PAF) antagonist (BN 52021) on antigen-induced prostaglandin and thromboxane formation by the guinea pig lung.

The effects of a new Platelet-Activating Factor (PAF-acether) antagonist (BN 52021) extracted from Ginkgo biloba leaves have been studied on the release of metabolites of arachidonic acid in IgG-dependent guinea pig pulmonary anaphylaxis in vitro. Prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) were assayed using a novel ELISA technique. The release of PGE2 and TxB2 from anaphylactic lungs reached a maximum 4-5 min following the antigen challenge (about 3.2 and 31.0 ng/ml respectively) and decayed slowly during the following 25 min. BN 52021 (1, 3 and 30 micrograms/ml) produced dose-dependent decreases of the release of PGE2 and TxB2. These results suggest that there are some interactions between the release of icosanoids and PAF-acether in anaphylaxis.

[Inhibition of platelet aggregation and thromboxane formation by the calcium antagonist nisoldipine following a single oral dose of 10 mg. A double-blind study in healthy probands]. / Hemmung der Plättchenaggregation und Thromboxanbildung durch den Calcium-Antagonisten Nisoldipin nach einer oralen Einmaldosis von 10 mg. Eine Doppelblind-Crossover-Studie bei gesunden Probanden.

The influence of the calcium antagonist nisoldipine on collagen-induced platelet aggregation and platelet thromboxane formation was studied ex vivo in healthy male volunteers in a double-blind, placebo-controlled crossover design. Measurements of general haemodynamics, immunoreactive 6-oxo-prostaglandin F1 alpha and thromboxane B2 ex vivo and collagen-induced (0.6 and 2.5 micrograms/ml) platelet aggregation were performed immediately before (time 0), 0.5 h, 1 h and 2 h after ingestion of 10 mg nisoldipine or an identical placebo tablet. Compared with the control response at time 0, administration of nisoldipine resulted in a significant inhibition of both low-collagen-induced platelet aggregation and formation of immunoreactive thromboxane B2 at time 0.5 h. There were no changes in heart rate or systolic blood pressure but a significant decrease in diastolic blood pressure by nisoldipine at 1 h. No such change was obtained with placebo and there were also no alterations with nisoldipine in platelet aggregation and thromboxane formation after stimulation by high-dose collagen at this or any other time of the study. The data demonstrate a platelet-inhibitory potential of nisoldipine in healthy men which is probably related to an increased resistance of the platelet membrane against foreign stimuli.