Pier Paolo Gazzaniga

Serum metalloproteinase 9 levels in patients with coronary artery disease: a novel marker of inflammation.

Background The finding that expression of metalloproteinases (MMPs) is induced in atherosclerotic plaques prone to rupture suggests the possibility that patients with atherosclerotic diseases would show enhanced blood levels of MMPs and that MMPs might represent a potential inflammatory risk factor for atherosclerosis. Therefore, the present study was aimed at verifying whether MMPs may represent sensitive markers of inflammation in patients with coronary artery disease. Methods MMP-2, MMP-9, interleukin (IL)-6, C-reactive protein (CRP), and fibrinogen levels were measured in blood samples obtained from 66 cases with previous acute myocardial infarction and 66 control subjects similar for age, sex, and major atherosclerotic risk factors but without history or evidence of atherothrombotic diseases. Results Biohumoral markers of inflammation and MMP-9 levels were significantly elevated in cases compared with controls (median values 40.6 versus 9.8 ng/mL; p < .0001), whereas MMP-2 levels did not differ between the two groups (median values 839 versus 873 ng/mL; p = .53). A direct correlation was found among MMP-9, CRP, IL-6, and fibrinogen levels. Conditional logistic regression analysis showed that MMP-9 is related to myocardial infarction (p = .006) even after adjusting for cardiovascular medications and CRP. Conclusion These findings suggest that measurement of serum MMP-9 levels may represent a novel marker of inflammation in patients with known coronary artery disease and might provide an index of plaque activity in this clinical setting.

Vitamin E inhibits collagen-induced platelet activation by blunting hydrogen peroxide.

In this study, we investigated whether vitamin E at concentrations achievable in blood after supplementation inhibits platelet function in humans. Gel-filtered platelets were incubated 30 minutes with scalar concentrations (50 to 250 mmol/L) of vitamin E and then stimulated with collagen. Compared with controls, vitamin E inhibited collagen-induced platelet aggregation and thromboxane A2 formation in a dose-dependent manner. Furthermore, vitamin E inhibited, in a dose-dependent manner, Ca(2+) mobilization and formation of inositol 1,4,5-triphosphate. Because it was previously shown that hydrogen peroxide formation mediates arachidonic acid metabolism and phospholipase C activation in collagen-induced platelet activation, we investigated whether vitamin E was able to blunt hydrogen peroxide. In experiments performed in unstimulated platelets supplemented with hydrogen peroxide and in collagen-stimulated platelets, vitamin E was able to blunt hydrogen peroxide. In 6 healthy subjects given vitamin E for 2 weeks (600 mg/d), we found a significant decrease of collagen-induced H(2)O(2) formation, platelet aggregation, and calcium mobilization. This study demonstrated in vitro and ex vivo that vitamin E inhibits collagen-induced platelet activation by blunting hydrogen peroxide formation.

Vascular endothelial growth factor (VEGF-A) plasma levels in non-small cell lung cancer: Relationship with coagulation and platelet activation markers

Platelet activation, commonly found in lung cancer patients, may cause the release of angiogenic factors, such as vascular endothelial growth factor (VEGF-A). The present study was designed to investigate whether plasma VEGF-A levels were associated to different stages of non-small cell lung cancer (NSCLC). Moreover, sP-selectin, prothrombin fragment 1+2 (F1+2), thrombin-antithrombin III complex (TATc) and D-dimer levels were measured to test the hypothesis of an involvement of platelet and coagulation activation in tumor angiogenesis. VEGF-A, sP-selectin, F1+2, TATc and D-dimer levels were elevated in 65 patients with NSCLC, particularly in metastatic patients. sP-selectin (p <0.003) and F1+2 (p <0.005) levels were independently associated to VEGF-A. In addition, patients with positive levels of both sP-selectin and F1+2 had the highest levels of VEGF-A. In conclusion, our findings support the hypothesis that thrombin generation might induce platelet activation and VEGF-A release in NSCLC.

Enhanced Interleukin-1β in Hypercholesterolemia Effects of Simvastatin and Low-Dose Aspirin

Background—This study was aimed at verifying whether activation of platelets might represent a source of interleukin (IL)-1&bgr; levels in hypercholesterolemia. To this purpose, we compared the effects of a short-term treatment with simvastatin or low-dose aspirin on circulating levels of this cytokine. Methods and Results—Fifty patients with hypercholesterolemia were randomly allocated to receive an 8-week therapeutic course of simvastatin 20 mg daily (n=25) or aspirin 100 mg daily (n=25). Baseline soluble (s) P-selectin directly correlated with IL-1&bgr; (P <0.0001) and C-reactive protein (CRP) (P <0.05) but not with von Willebrand factor, total cholesterol, or LDL cholesterol levels. Furthermore, sP-selectin (P <0.02) and IL-1&bgr; (P <0.0001) levels were independently related to CRP by multiple regression analysis. Both drugs were associated with comparable, significant reductions in IL-1&bgr; and sP-selectin. Simvastatin, but not aspirin treatment, significantly lowered CRP levels (P <0.05). The change in IL-1&bgr; levels correlated with the change in sP-selectin in patients randomized to either simvastatin (Rho, 0.42; P <0.05) or aspirin (Rho, 0.42; P <0.05). In contrast, the simvastatin-induced change in IL-1&bgr; did not correlate with the change in CRP levels. Conclusions—This study suggests that platelets might contribute to IL-1&bgr; production in hypercholesterolemia, thus providing an additional link between inflammation and the prothrombotic state in this setting.

Evidence for separate effects of U73122 on phospholipase C and calcium channels in human platelets

U73122 ((1-[6-(( 17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)exyl]-1H-p yrrole-2,5-dione)) is generally used as a selective inhibitor of phospholipase C (PLC) and the related rise in cytosolic Ca2+. Recently, by using hepatocytes, it was suggested that its action sites are different for PLC activation and increase in Ca2+ concentration. To verify whether U73122 has different sites for inhibiting PLC activation and calcium responses in human platelets, aggregation, Mn2+ influx, cytosolic Ca2+ increase and PLC activation were studied in response to thrombin and the synthetic agonist of the thromboxane receptor U46619 (9,11-dideoxy-9alpha,11alpha-methanoepoxyprostaglandin F2alpha). With both agonists, U73122 inhibited aggregation, Mn2+ influx and the enhancement of cytosolic calcium at concentrations of 2 microM or lower, while 10 microM was necessary to inhibit PLC activation. Our results suggested that U73122 is much more active in antagonizing Ca2+ channels, both the intracellular ones, which are activated by formation of inositol 1,4,5 P3 and those present on plasma membrane, than in reducing the activation of PLC.

Lipoprotein(a) serum levels in patients affected by chronic obstructive pulmonary disease

A recent study has suggested that symptoms of chronic bronchitis predict the risk of coronary disease independently of the known major cardiovascular risk factors. High serum levels of lipoprotein(a) (Lp(a)) have also been considered as an independent risk factor for coronary heart disease. Therefore, the aim of the present study was to investigate the behaviour of Lp(a) in patients affected by chronic obstructive pulmonary disease (COPD). Serum levels of total-cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglycerides, apolipoprotein (Apo) B-100, and Lp(a) were measured in 90 COPD patients and in 90 normal subjects matched for age, sex and smoking habit. COPD patients showed lower serum levels of Apo B-100 (P<0.0001) and Lp(a) (P<0.003) compared to controls. Conversely, TC, HDL-C, LDL-C and triglycerides were similar between patients and controls. No significant differences were found in Apo B-100 and Lp(a) levels of patients either undergoing different therapeutic regimens, or with different smoking habits. A significant correlation between Apo B-100 and Lp(a) (rho=0.433, P<0. 0001) was also observed. In conclusion, COPD patients do not show an atherogenetic lipid pattern and their increased risk of coronary disease could be attributable to different factors, such as the ongoing hypercoagulability state often associated with COPD.

Soluble P-Selectin and Proinflammatory Cytokines in Patients with Polygenic Type IIa Hypercholesterolemia

Plasma soluble P-selectin (sP-selectin), β-thromboglobulin (β-TG), von Willebrand Factor (vWF), prothrombin factor 1+2 (F1+2), IL-6 and IL-1β levels were analyzed in 35 consecutive patients with polygenic type IIa hypercholesterolemia (HC) and 35 age- and sex-matched healthy subjects. sP-selectin (p < 0.005), β-TG (p < 0.05) and IL-1β (p < 0.02) levels were higher in HC patients than healthy subjects whereas no significant difference was observed for vWF. sP-selectin directly correlated with β-TG (p < 0.05) and IL-1β levels (p < 0.005), but not with the other variables analyzed. A direct correlation was observed between F1+2 and IL-6 (p < 0.05), total cholesterol (p < 0.05) or LDL cholesterol (p < 0.05). We conclude that HC is associated with an increase of plasma sP-selectin levels, and that sP-selectin may be considered as a marker of in vivo platelet activation in type IIa polygenic HC. The correlations observed among the variables analyzed in the study suggest that proinflammatory cytokines might play a role in the prothrombotic state often associated with HC.

Protein kinase C activation is not a key step in ADP-mediated exposure of fibrinogen receptors on human platelets

A selective inhibitor of protein kinase C (PKC), Ro 31‐8220, blocks pleckstrin (P47) phosphorylation in platelets activated with either ADP, ADP plus synthetic thromboxane agonist U46619 and ADP plus U46619 plus epinephrine, while inducing a weak inhibition of platelet aggregation, and no significant effect on the fibrinogen binding. In platelets activated by U46619 alone, P47 phosphorylation, platelet aggregation, fibrinogen binding and serotonin release are all inhibited by Ro 318220. In the presence of an ADP scavenger system, U46619 induces pleckstrin phosphorylation, serotonin release and calcium mobilization but not platelet aggregation and fibrinogen binding, unless epinephrine is added. In conclusion: (1) PKC activation is required for ADP secretion; (2) ADP or epinephrine are essential for fibrinogen receptor exposure induced by U46619; (3) fibrinogen receptor exposure induced by ADP is independent of activation of PKC.

Blood Leukotrienes in Headache: Correlation With Platelet Activity

SYNOPSIS

Platelet Hyperactivity in Hypertensive Older Patients Is Controlled by Lowering Blood Pressure

Patients with hypertension tend to have a high prevalence of atherothrombotic accidents. Platelet hyperactivity is frequently associated with hypertension. Because the vascular disease associated with hypertension evolves over the years, we investigated platelet activity parameters in a population of older hypertensive patients with no other risk factors for cardiovascular disease.