Blood biomarkers for occupational hand-arm vibration exposure.

Hand-arm vibration is a common occupational exposure that causes neurological impairment, myalgia, and vibration-induced Raynaud's phenomena or vibration white fingers (VWF). The pathological mechanism is largely unknown, though several mechanisms have been proposed, involving both immunological vascular damage and defective neural responses. The aim of this study was to test whether the substances interleukin-33 (IL-33), macrophage-derived chemokine (MDC), interleukin-10 (IL-10), endothelin-1 (ET-1), C-C motif chemokine ligand 20 (CCL20), calcitonin, and thromboxane (TXA2) changed before and after occupational hand-arm vibration exposure. 38 full-time shift workers exposed to hand-arm vibration were recruited. All the participants underwent medical examinations regarding symptoms of Raynaud's phenomena. In 29 of the participants, the concentration of IL-33, MDC, IL-10, ET-1, CCL20, calcitonin, and TXA2 was measured before and after a workday. There was a significant increase in ET-1 and calcitonin concentration and a decrease in the CCL20 concentration after the work shift in all participants. In the group suffering from VWF, but not in the non-VWF group, MDC was statistically significantly lower before the work shift (p = .023). The VWF group also showed a significant increase in MDC after the work shift. Exposure to occupational hand-arm vibration is associated with changes in ET-1, calcitonin, and MDC concentration in subjects suffering from vibration white fingers, suggesting a role of these biomarkers in the pathophysiology of this condition.

Correlation of platelet-derived growth factor and thromboxane A2 expression with platelet parameters and coagulation indices in chronic altitude sickness patients.

NEW FINDINGS: What is the central question of this study? Is the expression of platelet-derived growth factor (PDGF) and thromboxane A2 (TXA2) elevated in chronic altitude patients, and are they related to thrombosis in chronic mountain sickness? What is the main finding and its importance? The expression of PDGF and TXA2 in both the bone marrow and the peripheral blood of patients with chronic mountain sickness is elevated, and they are considered to be correlated in the mechanism of thrombosis in the chronic mountain sickness. ABSTRACT: The purpose of this study was to evaluate the expression of platelet-derived growth factor (PDGF) and thromboxane A2 (TXA2) along with platelet parameters and coagulation indices in chronic mountain sickness (CMS) patients and healthy individuals on the Qinghai-Tibet Plateau. The levels of PDGF and TXA2 were examined in 22 CMS patients (age, 52.77 ± 9.92 years, haemoglobin, 219 ± 13 g/l) and 25 healthy individuals (age, 47.80 ± 9.78 years, haemoglobin, 146 ± 18 g/l), and the association between platelet parameters and coagulation indices was investigated. Mean platelet volume and fibrinogen degradation product were higher in the CMS compared to the control group (10.58 ± 0.83 vs. 8.92 ± 1.61, 7.50 ± 2.15 vs. 4.40 ± 2.51), platelet count and plateletcrit were lower in the CMS compared to the control group (0.13 (0.80, 0.16) vs. 0.23 (0.18, 0.24), 109 ± 46 vs. 204 ± 86). The levels of PDGF and TXA2 in the bone marrow and peripheral blood of CMS patients were higher (P < 0.01) in comparison to the control group. The two factors had no statistically significant relationship with platelet parameters or coagulation indices (P > 0.159). According to the current findings, platelets in CMS patients were activated, resulting in aberrant coagulation and PDGF and TXA2 expression, which could be due to physiological adjustments to the plateau's high altitude. To summarize, PDGF and TXA2 levels in CMS patients were not correlated with coagulation or platelet parameters, implying that the mechanism behind their increased expression warrants additional investigation.

Effect of Berberine on Cardiovascular Disease Risk Factors: A Mechanistic Randomized Controlled Trial.

Cardiovascular disease (CVD) is a major contributor to the global burden of disease. Berberine, a long-standing, widely used, traditional Chinese medicine, is thought to have beneficial effects on CVD risk factors and in women with polycystic ovary syndrome. The mechanisms and effects, specifically in men, possibly via testosterone, have not been examined previously. To assess the effect of berberine on CVD risk factors and any potential pathway via testosterone in men, we conducted a randomized, double-blind, placebo-controlled, parallel trial in Hong Kong. In total, 84 eligible Chinese men with hyperlipidemia were randomized to berberine (500 mg orally, twice a day) or placebo for 12 weeks. CVD risk factors (lipids, thromboxane A2, blood pressure, body mass index and waist-hip ratio) and testosterone were assessed at baseline, and 8 and 12 weeks after intervention. We compared changes in CVD risk factors and testosterone after 12 weeks of intervention using analysis of variance, and after 8 and 12 weeks using generalized estimating equations (GEE). Of the 84 men randomized, 80 men completed the trial. Men randomized to berberine had larger reductions in total cholesterol (-0.39 mmol/L, 95% confidence interval (CI) -0.70 to -0.08) and high-density lipoprotein cholesterol (-0.07 mmol/L, 95% CI -0.13 to -0.01) after 12 weeks. Considering changes after 8 and 12 weeks together, berberine lowered total cholesterol and possibly low-density lipoprotein-cholesterol (LDL-c), and possibly increased testosterone. Changes in triglycerides, thromboxane A2, blood pressure, body mass index and waist-hip ratio after the intervention did not differ between the berberine and placebo groups. No serious adverse event was reported. Berberine is a promising treatment for lowering cholesterol. Berberine did not lower testosterone but instead may increase testosterone in men, suggesting sex-specific effects of berberine. Exploring other pathways and assessing sex differences would be worthwhile, with relevance to drug repositioning and healthcare.

Low-dose Aspirin prevents hypertension and cardiac fibrosis when thromboxane A2 is unrestrained.

Enhanced platelet activation has been reported in patients with essential hypertension and heart failure. The possible contribution of platelet-derived thromboxane (TX)A2 in their pathophysiology remains unclear. We investigated the systemic TXA2 biosynthesis in vivo and gene expression of its receptor TP in 22 essential hypertension patients and a mouse model of salt-sensitive hypertension. The contribution of platelet TXA2 biosynthesis on enhanced blood pressure (BP) and overload-induced cardiac fibrosis was explored in mice by treating with low-dose Aspirin, resulting in selective inhibition of platelet cyclooxygenase (COX)-1-dependent TXA2 generation. In essential hypertensive patients, systemic biosynthesis of TXA2 [assessed by measuring its urinary metabolites (TXM) reflecting predominant platelet source] was enhanced together with higher gene expression of circulating leukocyte TP and TGF-ß, vs. normotensive controls. Similarly, in hypertensive mice with prostacyclin (PGI2) receptor (IP) deletion (IPKO) fed with a high-salt diet, enhanced urinary TXM, and left ventricular TP overexpression were detected vs. normotensive wildtype (WT) mice. Increased cardiac collagen deposition and profibrotic gene expression (including TGF-ß) was found. Low-dose Aspirin administration caused a selective inhibition of platelet TXA2 biosynthesis and mitigated enhanced blood pressure, cardiac fibrosis, and left ventricular profibrotic gene expression in IPKO but not WT mice. Moreover, the number of myofibroblasts and extravasated platelets in the heart was reduced. In cocultures of human platelets and myofibroblasts, platelet TXA2 induced profibrotic gene expression, including TGF-ß1. In conclusion, our results support tailoring low-dose Aspirin treatment in hypertensive patients with unconstrained TXA2/TP pathway to reduce blood pressure and prevent early cardiac fibrosis.

The Protective Effect of Aspirin against Myocardial Hypertrophy in Rats.

The protective effect of aspirin against myocardial hypertrophy (MH) was studied. Model rats of pressure overload MH were prepared by abdominal aortic coarctation. Rats were randomly divided into the sham group (n = 9), MH model group (n = 9), and MH+aspirin group (n = 9), which was, respectively, divided into the 4-week group and 8-week group according to the time of intragastric administration. Arterial blood pressure and left ventricular mass index (LVMI) were measured. Changes in myocardial tissue structure were observed by HE staining, Masson staining, and reticular fiber staining. Cardiomyocyte apoptosis was detected by TUNEL assay. The levels of TNF-α, IL-10, TXA2, and PGI2 in myocardium and plasma were detected by ELISA. The arterial blood pressure in the MH model group was significantly higher than that in the 4- and 8-week sham groups, but that in the MH+aspirin group was significantly lower than that in the MH model group. At 4 and 8 weeks, the LVWI in the MH model group was significantly higher than that in the sham group, but it was significantly reduced after aspirin treatment. The myocardial cell hypertrophy was obvious, collagen fibers were proliferated, and reticular fibers were reduced in the 4- and 8-week MH model groups. Compared with the MH model groups, myocardial cells in the MH+aspirin groups were significantly reduced, the collagen fiber content was significantly reduced, and the reticular fiber content was increased. The apoptotic cardiomyocytes in the 4- and 8-week MH model groups were obviously increased. The apoptosis of myocardial cells in the MH+aspirin groups was obviously decreased. The TNF-α levels in the myocardial tissue of the 4- and 8-week MH model groups were significantly increased, while those of the MH+aspirin groups were significantly decreased. There was no significant change in the IL-10 level or PGI2 level at 4 weeks. At 8 weeks, the PGI2 level was significantly decreased in the MH model group while significantly increased in the MH+aspirin group. The TXA2 levels were significantly increased in the 4- and 8-week MH model groups and those in the 4- and 8-week MH+aspirin groups were significantly lower. Aspirin has an anti-inflammatory effect, can effectively reduce the expression of inflammatory factors, inhibit myocardial apoptosis, and has a certain protective effect against MH.

Persistent long-term platelet activation and endothelial perturbation in women with Takotsubo syndrome.

BACKGROUND: Takotsubo (TTS) syndrome is an acute cardiac condition characterized by transient and reversible left ventricle dysfunction that mainly affects postmenopausal women. Catecholamine burst is the most accredited mechanism underpinning TTS onset and leading to endothelial dysfunction and platelet activation. Even if the use of low dose acetylsalycilic acid (ASA) in this clinical setting is based on both clinical presentation and unfavorable long-term prognosis, its efficacy has been recently challenged. AIM: This study was designed to assess endothelial function, residual thromboxane formation and platelet aggregation in TTS women on low-dose ASA treatment at long-term follow-up. METHODS: Twenty-eight females with previously diagnosis of TTS syndrome were enrolled. Data were compared to those obtained from 23 coronary artery disease (CAD) women with a history of acute myocardial infarction, and 26 control subjects with no TTS or clinically evident CAD. Psychological and clinical profile were assessed in all study groups at the enrollment. Main metabolites involved in L-arginine/nitric oxide pathway, urinary prostacyclin, serum and urine thromboxane metabolites were measured by LCMS/MS methods. Thrombomodulin levels were quantified using an ELISA kit, and platelet aggregation, carried out on platelet rich-plasma, was induced by ADP or by epinephrine (EPI), norepinephrine (NORE) and TRAP-6, alone or in association with ADP and evaluated by Born's method. RESULTS: In TTS women an endothelial derangement, characterized by reduced citrulline production and increased thrombomodulin concentration, with no perturbation in prostacyclin levels, was evidenced. In addition, despite ASA treatment, TTS displayed a higher residual thromboxane formation, in parallel with an enhanced platelet response to compared to CAD. CONCLUSIONS: Our study highlighted the presence of endothelial perturbation in TTS patients even at long-term from the index event. The residual thromboxane production and platelet aggregation still leave open the question about the use of low dose ASA in this clinical setting.

Blood biomarkers for vibration-induced white fingers. A case-comparison study.

BACKGROUND: Vibration induced white fingers (VWF) is one form of secondary Raynaud's phenomenon (RP). METHODS: Vibration exposed workers with RP and vibration exposed controls without RP participated. Blood samples were collected before and after cold challenge exposure (COP). The concentration of von Willebrand factor (vonWf), thrombomodulin (TM), serotonin (SER), endothelin-1 (ET1 ), calcitonin gene-related peptide, or thromboxane A2 was calculated. The diagnostic usefulness of the substances for ruling in the diagnosis of Raynaud's was evaluated. RESULTS: The cases showed a significant lower concentration of vonWf before and after COP, a significant increase of ET1  and a decrease of TM after COP. The diagnostic usefulness of vonWf showed a likelihood of defining a true case by 35%. CONCLUSIONS: vonWf, TM, SER, or ET1 are suggested biomarkers for VWF. Diagnostic evaluation of vonWf showed a likelihood of defining a true case by 35% in the diagnosis of RP related to vibration.

NAADP/SERCA3-Dependent Ca2+ Stores Pathway Specifically Controls Early Autocrine ADP Secretion Potentiating Platelet Activation.

RATIONALE: Ca2+ signaling is a key and ubiquitous actor of cell organization and its modulation controls many cellular responses. SERCAs (sarco-endoplasmic reticulum Ca2+-ATPases) pump Ca2+ into internal stores that play a major role in the cytosolic Ca2+ concentration rise upon cell activation. Platelets exhibit 2 types of SERCAs, SERCA2b and SERCA3 (SERCA3 deficient mice), which may exert specific roles, yet ill-defined. We have recently shown that Ca2+ mobilization from SERCA3-dependent stores was required for full platelet activation in weak stimulation conditions. OBJECTIVE: To uncover the signaling mechanisms associated with Ca2+ mobilization from SERCA3-dependent stores leading to ADP secretion. METHODS AND RESULTS: Using platelets from wild-type or Serca3-deficient mice, we demonstrated that an early (within 5-10 s following stimulation) secretion of ADP specifically dependent on SERCA3 stored Ca2+ is exclusively mobilized by nicotinic acid adenosine dinucleotide-phosphate (NAADP): both Ca2+ mobilization from SERCA3-dependent stores and primary ADP secretion are blocked by the NAADP receptor antagonist Ned-19, and reciprocally both are stimulated by permeant NAADP. In contrast, Ca2+ mobilization from SERCA3-dependent stores and primary ADP secretion were unaffected by inhibition of the production of IP3 (inositol-1,4,5-trisphosphate) by phospholipase-C and accordingly were not stimulated by permeant IP3. CONCLUSIONS: Upon activation, an NAADP/SERCA3 Ca2+ mobilization pathway initiates an early ADP secretion, potentiating platelet activation, and a secondary wave of ADP secretion driven by both an IP3/SERCA2b-dependent Ca2+ stores pathway and the NAADP/SERCA3 pathway. This does not exclude that Ca2+ mobilized from SERCA3 stores may also enhance platelet global reactivity to agonists. Because of its modulating effect on platelet activation, this NAADP-SERCA3 pathway may be a relevant target for anti-thrombotic therapy. Graphic Abstract: A graphic abstract is available for this article.

Protective Effect of Saponins-Enriched Fraction of Gynostemma pentaphyllum against High Choline-Induced Vascular Endothelial Dysfunction and Hepatic Damage in Mice.

Choline as a quaternary amine nutrient is metabolized to trimethylamine by gut microbiota and subsequently oxidized to circulating trimethylamine-N-oxide (TMAO), a gut-derived metabolite associated with liver toxicity and cardiovascular disease. The study was to probe the possible vasoprotective and hepatoprotective effects of total saponins of Gynostemma pentaphyllum (TSGP) in 3% high-choline water-feeding mice. The purified TSGP was obtained with content of 83.0% saponins, and its antioxidant activities were evaluated in vitro. Furthermore, the mice fed with high choline for 8 weeks significantly expressed vascular endothelial dysfunction and liver oxidative stress (p < 0.01 vs. Normal). Administration of TSGP at 400 and 800 mg/kg·body weight (b.w.) significantly lowered the serum total cholesterol (TC), triglyceride (TG), low density lipoprotein-cholesterol (LDL-C), endothelin-1 (ET-1) and thromboxane A2 (TXA2) levels, as well as hepatic malondialdehyde (MDA) formation, but effectively elevated the serum nitric oxide (NO), endothelial nitric oxide synthase (eNOS) and prostaglandin I2 (PGI2) levels, as well as alanine aminotransferase (ALT), aspartate aminotransferase (AST), T-superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in high choline-fed mice. Hematoxylin-eosin (H&E) and oil red O staining also suggested that TSGP could exert the significant protection against endothelial dysfunction and liver injury in high choline-treated mice. These findings suggest that TSGP is of the saponins-enriched extract, and is a good candidate of dietary supplement and therapeutic application in vascular and hepatic oxidative injury.

Weight as an assay-independent predictor of poor response to enteric aspirin in cardiovascular patients.

Aspirin non-response is associated with poor outcome but there is no agreement between the different methods to asses it. Weight has been shown to be a predictor of poor response but only using one method. In this study, we determine the effects of weight on different assays of platelet function. The response to aspirin was determined in 138 cardiology patients using serum thromboxane, arachidonic acid-induced platelet aggregation and VerifyNow©. Twenty-five percent of patients showed an inadequate response to aspirin in at least one assay on the initial test. After ensuring patient compliance only 5% of patients were considered to be non-responders. Only 9% of non-responders were non-responsive in all three assays. When switched to plain aspirin, only 2% of patients were non-responsive. All patients responded adequately to 150 mg aspirin. The non-responders were significantly heavier than responders (78.5 kg ± 14.0 (SD); BMI: 28.4 kg/m2± 4.4 v's 102.6 kg ± 20.6, P = .0016; BMI: 38.3 kg/m2 ± 7.6, P= .0015). A rule-based approach of using plain aspirin in patients over 90 kg or BMI 32 along with patient education to ensure compliance will ensure that all patients respond to their aspirin without the need for testing.

Targeting the COX1/2-Driven thromboxane A2 pathway suppresses Barrett's esophagus and esophageal adenocarcinoma development.

BACKGROUND: Barrett's esophagus (BE), a complication of gastroesophageal reflux disease (GERD), predisposes patients to esophageal adenocarcinoma (EAC). Reliable biomarkers for early detection and discovery of potential drug targets are urgently needed for improved BE and EAC patient outcomes. METHODS: Patient biopsy samples were evaluated for COX1/2, and thromboxane A2 synthase (TBXAS) expression. Circulating prostaglandins biosynthesis was determined using enzyme immunoassay kits. Anchorage-independent cell growth assay, crystal violet staining assay, and xenograft experiments were conducted to assess BE and EAC cell growth. A surgical mouse model of reflux (i.e., esophagoduodenostomy) was established and samples were analyzed using an enzyme immunoassay kit, immunohistochemistry, immunoblotting, or RT-PCR. Esophageal biopsy samples (pre- and post-intervention) were obtained from a randomized clinical trial in which participants were administered esomeprazole (40 mg) twice daily in combination with an acetylsalicylic acid (ASA) placebo or 81 or 325 mg ASA for 28 days. Esophageal biopsy specimens before and after the intervention period were analyzed. FINDINGS: COX2 and TBXAS are highly expressed in BE and EAC patients accompanied by a pronounced elevation of circulating TXA2 levels. ASA suppressed BE and EAC growth by targeting the TXA2 pathway. Additionally, biopsies from 49 patients (with similar baseline characteristics) showed that ASA substantially decreased serum TXA2 levels, resulting in reduced inflammation. INTERPRETATION: This study establishes the importance of the COX1/2-driven TXA2 pathway in BE and EAC pathophysiology and lays the groundwork for introducing a TXA2-targeting strategy for EAC prevention and early detection. FUNDING: Hormel Foundation, Exact Sciences, Pentax Medical, Intromedic and National Cancer.

Stability of thromboxane in blood samples.

Introduction: Conventional venous blood collection requires a puncture with a needle through the endothelium of a vessel. The endothelial injury causes activation of circulating platelets and the release of thromboxane A2. The aim of the study was to investigate if platelets continue to form thromboxane A2 in the blood tube after sample collection, but such synthesis would give false information about the actual circulating thromboxane A2 value. Methods: Thromboxane B2 is a biologically inactive but stable metabolite of thromboxane A2 and can be measured in blood samples by a standard enzyme immunoassay. Thromboxane B2 measurements reflect thromboxane A2 concentration. Blood samples were collected in 3.2% sodium citrate vials and EDTA vials from ten individuals and centrifuged and frozen at different time points (0, 30, and 120 minutes). Plasma aliquots were transferred to and frozen in 1.8 mL polypropylene tubes and the citrate samples were also transferred to and frozen in propylene tubes containing indomethacin. Results: Concentrations of thromboxane B2 in plasma samples collected in citrate vials and stored in propylene tubes increased very rapidly as the samples were left for longer after sampling and allowed to stand at room temperature. After 120 minutes, the amount of thromboxane B2 was 400% higher than in the reference sample at time zero. In comparison, thromboxane B2 concentration was about 200% higher in the 120-minute samples compared to the reference in samples collected in citrate vials but stored in indomethacin tubes. In samples collected in EDTA vials, a 10% reduction in thromboxane B2 concentration in the 120-minute samples was observed. Conclusion: Storage conditions, type of sampling vial and time from sampling until sample processing (centrifuging) has a major impact on thromboxane B2 stability.

UPLC-Q-TOF/MS-Based Plasma Metabolomics to Evaluate the Effects of Aspirin Eugenol Ester on Blood Stasis in Rats.

Aspirin eugenol ester (AEE) is a novel compound that is formed from the esterification of aspirin (acetylsalicylic acid (ASA)) and eugenol. This study aimed to investigate the effects of AEE on blood stasis in rats and to characterize the underlying mechanisms using a plasma metabolomic study. The results indicate that AEE and ASA could modulate whole blood viscosity (WBV), plasma viscosity (PV), blood coagulation parameters, platelet count, platelet aggregation, lactate dehydrogenase (LDH), creatinine (CR) and the levels of thromboxane A2 (TXA2) and 6-keto prostaglandin F1α (6-keto-PGF1α). The metabolic profiles of the plasma samples from all groups were clearly separated in the score plots. Nineteen potential metabolites were selected and identified, and disordered levels of these metabolites could be regulated by AEE and ASA. Pathway analysis showed that the mechanism of action of AEE on blood stasis might be principally related to the metabolism of amino acid, fatty acid, energy and glycerophospholipid. The above results indicate that AEE protected the rats against blood stasis, and that this effect might have been caused by the anticoagulation activity of AEE and its abilities to maintain a balance between TXA2 and PGI2, reduce blood viscosity, inhibit platelet aggregation and normalize the plasma metabolic profile.

Methanolic root extract of Codonopsis clematidea prevents hypoxia induced procoagulant state by inhibition of GPIb receptor regulated Lyn kinase activation.

BACKGROUND: The prevalence of procoagulant state under prolonged hypoxic exposures and the complications and lack of specificity associated with use of existing anti-thrombotic agents have necessitated the search for safer and natural therapeutics. Codonopsis, a widely studied medicinal herb, has been reported to decrease whole blood viscosity but the bioactive ingredients involved, and their mechanism of action therein however remain to be investigated. PURPOSE: The present study aimed at evaluating the efficacy of C. clematidea root extract and mechanism of action of its bioactive constituent flavonoid, Kaempferol, in ameliorating hypobaric hypoxia induced procoagulant state. METHODS: Fingerprinting analysis of methanolic extract of C. clematidea root was performed by RP-HPLC. In vitro toxicity study was conducted using HUVEC cell line and in vivo acute and sub-acute toxicity were done according to OECD guidelines (section-4, number-420 and 407 respectively). Adult male Sprague-Dawley rats weighing 230-250 g were exposed to global hypoxia simulating an altitude of 7600 m (282 mmHg), in animal decompression chamber for 3, 7, 14 and 21 days for in vivo studies. Dose optimisation of the extract was done by quantification of Thromboxane A2 in the serum of hypoxic rats. C. clematidea root extract was also evaluated for its in vitro and in vivo antioxidant properties. Procoagulant changes were studied by biochemical plasma coagulation assays and expression analysis of the signalling molecules of the platelet activation cascade like vWF, platelet activation marker CD41, GpIb-IX-V (CD42), Lyn kinase, p-PI3K, p-ERK and p-PLCγ were conducted to investigate C. clematidea mediated signalling mechanisms. RESULTS: Methanolic extract of C. clematidea root showed improved antioxidant status and improvement in bleeding time and in vitro coagulation assays like pT, aPTT, INR. Decreased concentrations of D-Dimers along with that of platelet activation marker CD41 and serum concentration of Thromboxane A2 were observed in C. clematidea root extract supplemented hypoxic animals. Phosphorylation of Lyn kinase, was reduced despite increase in concentration of activating ligand vWF. CONCLUSION: C. clematidea root extract was effective in preventing hypoxia induced platelet activation and resultant procoagulant state by inhibiting Lyn kinase, a serine threonine kinase effector of vWF signalling cascade.

Effects of three-month streptozotocin-induced diabetes in mice on blood platelet reactivity, COX-1 expression and adhesion potential.

Diabetes is associated with an increased risk of cardiovascular disease. This is partially attributed to an altered activation status of blood platelets in this disease. Previously, alterations have been shown in COX-1 and protease activated receptor (PAR)-3 receptor expression in platelets in two animal models of diabetes, there have not been studies which address expression of these proteins in mice with long-term streptozotocin (STZ)-induced diabetes. We have also addressed the effect of diabetes on platelet adhesion under flow conditions. With the use of flow cytometry, we have shown that certain markers of platelet basal activation, such as active form of αIIb ß3 and of CD40L were increased in STZ-induced diabetic mice. Platelets from STZ-induced diabetic mice were also more reactive when stimulated with PAR-4 activating peptide as revealed by higher expression of active form of αIIb ß3 , membrane-bound on vWillebrand Factor and binding of exogenous fluorescein isothyanate-labelled fibrinogen. Expression of COX-1 and production of thromboxane A2 in platelets of STZ-induced diabetic mice were higher than in control animals. We observed no effect of diabetes on ability of platelets to form stable adhesions with fibrinogen in flow conditions. We conclude that although certain similarities exist between patterns of activation of platelets in animal models of diabetes, the differences should also be taken into account.

Protective Effects of Baicalin on Experimental Myocardial Infarction in Rats.

OBJECTIVE: This study aimed to investigate the protective effects of baicalin on myocardial infarction in rats and explore the related mechanisms. METHODS: Fifty Sprague Dawley rats were randomly divided into the control, model, and low-, medium- and high-dose baicalin groups. The latter 3 groups were intraperitoneally injected with baicalin, with a dose of 12.5, 25 and 50 mg/kg, respectively. Then, the myocardial infarction model was established. The hemodynamic of rats was tested, the serum lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB), prostacyclin (PGI2) and thromboxane A2 (TXA2) were determined, the myocardial superoxide dismutase (SOD) and malondialdehyde (MDA) levels were detected, and the myocardial B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X (Bax) protein expressions were determined. RESULTS: Compared with the model group, in the high-dose baicalin group the ST segment height and LVEDP were significantly decreased (P<0.05), the LVSP was significantly increased (P<0.05), the serum LDH, CK-MB and TXA2 levels were significantly decreased (P<0.05), the PGI2 level was significantly increased (P<0.05), the myocardial SOD level was significantly increased (P<0.05), and the myocardial MDA level was significantly decreased (P<0.05); the myocardial Bcl-2 protein level was significantly increased, and the Bax protein level was significantly decreased (P<0.05). CONCLUSION: Baicalin has protective effects on myocardial infarction in rats. The possible mechanisms may be related to its resistance to oxidative stress, and up-regulation of Bcl-2 protein expression and down-regulation of Bax protein expression in myocardial tissue.

The effects of inhaled NO on plasma vasoactive factor and CTnI level in rabbits with acute massive pulmonary embolism1.

PURPOSE: To investigate changes in the plasma concentrations of cardiac troponin I (CTnI), thromboxane A2 (TXA2), prostaglandin I2 (PGI2) and endothelin-1 (ET-1) in rabbits with massive pulmonary embolism (AMPE) and the impact of nitric oxide inhalation (NOI) on these indices. METHODS: A total of 30 Japanese rabbits were used to construct an MPE model and were divided into 3 groups equally (n=10), including an EXP group (undergoing modeling alone), an NOI group (receiving NOI 2 h post-modeling) and a CON group (receiving intravenous physiological saline). RESULTS: In the model group, plasma concentration of CTnI peaked at 16 h following modeling (0.46±0.10 µg/ml) and significantly decreased following NOI. Plasma levels of TXB2, PGI2 and ET-1 peaked at 12, 16 and 8 h following modeling, respectively, and significantly decreased at different time points (0, 2, 4, 8, 12, 16, 20 and 24 h) following NOI. A significant correlation was observed between the peak plasma CTnI concentration and peak TXB2, 6-keto prostaglandin F1α and ET-1 concentrations in the model and NOI groups. CONCLUSION: Increases in plasma TXA2, PGI2 and ET-1 levels causes myocardial damage in a rabbit model of AMPE; however, NOI effectively down regulates the plasma concentration of these molecules to produce a myocardial-protective effect.

Protective effects of baicalin on experimental myocardial infarction in rats

Abstract Objective: This study aimed to investigate the protective effects of baicalin on myocardial infarction in rats and explore the related mechanisms. Methods: Fifty Sprague Dawley rats were randomly divided into the control, model, and low-, medium- and high-dose baicalin groups. The latter 3 groups were intraperitoneally injected with baicalin, with a dose of 12.5, 25 and 50 mg/kg, respectively. Then, the myocardial infarction model was established. The hemodynamic of rats was tested, the serum lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB), prostacyclin (PGI2) and thromboxane A2 (TXA2) were determined, the myocardial superoxide dismutase (SOD) and malondialdehyde (MDA) levels were detected, and the myocardial B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X (Bax) protein expressions were determined. Results: Compared with the model group, in the high-dose baicalin group the ST segment height and LVEDP were significantly decreased (P<0.05), the LVSP was significantly increased (P<0.05), the serum LDH, CK-MB and TXA2 levels were significantly decreased (P<0.05), the PGI2 level was significantly increased (P<0.05), the myocardial SOD level was significantly increased (P<0.05), and the myocardial MDA level was significantly decreased (P<0.05); the myocardial Bcl-2 protein level was significantly increased, and the Bax protein level was significantly decreased (P<0.05). Conclusion: Baicalin has protective effects on myocardial infarction in rats. The possible mechanisms may be related to its resistance to oxidative stress, and up-regulation of Bcl-2 protein expression and down-regulation of Bax protein expression in myocardial tissue.

The effects of inhaled NO on plasma vasoactive factor and CTnI level in rabbits with acute massive pulmonary embolism

Abstract Purpose: To investigate changes in the plasma concentrations of cardiac troponin I (CTnI), thromboxane A2 (TXA2), prostaglandin I2 (PGI2) and endothelin-1 (ET-1) in rabbits with massive pulmonary embolism (AMPE) and the impact of nitric oxide inhalation (NOI) on these indices. Methods: A total of 30 Japanese rabbits were used to construct an MPE model and were divided into 3 groups equally (n=10), including an EXP group (undergoing modeling alone), an NOI group (receiving NOI 2 h post-modeling) and a CON group (receiving intravenous physiological saline). Results: In the model group, plasma concentration of CTnI peaked at 16 h following modeling (0.46±0.10 µg/ml) and significantly decreased following NOI. Plasma levels of TXB2, PGI2 and ET-1 peaked at 12, 16 and 8 h following modeling, respectively, and significantly decreased at different time points (0, 2, 4, 8, 12, 16, 20 and 24 h) following NOI. A significant correlation was observed between the peak plasma CTnI concentration and peak TXB2, 6-keto prostaglandin F1α and ET-1 concentrations in the model and NOI groups. Conclusion: Increases in plasma TXA2, PGI2 and ET-1 levels causes myocardial damage in a rabbit model of AMPE; however, NOI effectively down regulates the plasma concentration of these molecules to produce a myocardial-protective effect.