Role of platelets in tissue factor expression by monocytes in normal and hypercholesterolemic subjects. In vitro effect of cerivastatin

Platelet lipidome: Dismantling the "Trojan horse" in the bloodstream

The platelet-lipid chapter in the story of atherothrombosis is an old one, recapitulated and revised in many contexts. For decades several stimulating facets have been added to it, both unraveling and increasing the perplexity of platelet-lipid interplay and its pathophysiological consequences. The recent paradigm shift in our perspective has evolved with lipidomic analysis of the intraplatelet compartment and platelet releasate. These investigations have disclosed that platelets are in constant interaction with circulatory lipids, often reflected in their lipid repertoire. In addition, they offer a shielded intracellular space for oxidative lipid metabolism generating "toxic" metabolites that escape degradation by plasma lipases and antioxidant defense, circulate undetected by conventional plasma lipid profile, and deposited at atherosclerotic lesions or thrombus. Lipidomics divulges this silent invader in platelet vehicles, thereby providing potential biomarkers of pathologic manifestations and therapeutic targets to be exploited, which is surmised in this review.

Association Between Air Temperature and the Incidence of Acute Coronary Heart Disease in Northeast China

Aim

The aim of this study was to examine the association between air temperature and incidence of acute coronary heart disease in Northeast China.

Methods

We obtained coronary heart disease (CHD) daily hospitalization data from January 2017 to June 2019, and collected meteorological data including average daily air temperature, air pressure, relative humidity, wind velocity, sunshine duration and water vapor pressure, for the same period. Totally, This study included data from 6775 patients with CHD.

Results

After adjusting for confounding factors, low air temperature was inversely associated with CHD. Additionally, in the warm season (April–September), the number of daily hospital admissions for CHD was higher (≥24.2°C) if the average daily air temperature was low (≤15.4°C).

Conclusion

Low air temperature might be a risk factor for CHD among the elderly, especially in the warm season.

Effect of Simvastatin on Thrombopoiesis in Porcine Bone Marrow

Introduction

Statins are pharmacological agents commonly used to lower serum cholesterol level. The aim of the experiment was to investigate the effect of the statin simvastatin on thrombopoiesis in the porcine model because it is the closest to the human one regarding physiological and genetic similarities.

Material and Methods

The study was conducted on a group of 32 pigs randomly divided into two equal groups: control and experimental. The pigs were treated for 28 and 56 days with simvastatin in a dose of 40 mg per day per animal. Cytological evaluation of bone marrow smears was performed to assess the average number of all types of cells during thrombopoiesis as was analysis of haematological parameters to assess PLT and MPV.

Results

During the course of the experiment statistically significant changes in the number of promegakaryocytes were observed. Other parameters also showed some fluctuations during the study. However, these changes were not statistically significant.

Conclusion

The obtained results clearly indicate a toxic influence of simvastatin on the process of thrombopoiesis and prove that statins reduce mean platelet volume, thus affecting the process of clot formation through the period of administration in a duration-dependent manner.

Simvastatin-induced Changes in the Leukocytic System of Porcine Bone Marrow

Introduction

Simvastatin is a substance which is commonly used as a medicine to reduce cholesterol level. Unfortunately, it shows numerous side effects. Simvastatin affects various internal organs, and among other detriments to health may cause persistent muscle weakness, osteolytic processes, headaches, and rashes. Until now knowledge of the influence of simvastatin on bone marrow cells has been rather scant and fragmentary.

Material and Methods

During this experiment the numbers of all types of cells in the leukocytic system of porcine bone marrow were evaluated after 28 and 56 days of oral administration of simvastatin at a dose of 40 mg/day/animal.

Results

Simvastatin caused an increase in the number of all types of cells in the leukocytic system, and the most visible fluctuations concerned promyelocytes.

Conclusion

Observations obtained during the present study indicated that the results of the action of simvastatin on porcine bone marrow differ from those observed in other mammal species, including human. This may be due to various metabolic pathways within the bone marrow in the particular species, but the exact mechanisms of these actions are unknown at the present time.

Amaranth peptides decreased the activity and expression of cellular tissue factor on LPS activated THP-1 human monocytes

The immunomodulatory activity of amaranth peptides is linked for the first time with their antithrombotic activity. Inhibition of tissue factor expression and the NF-κB pathway was observed after treatment with the peptides.

Hyperlipidemia, tissue factor, coagulation, and simvastatin

Hyperlipidemia affects millions of people worldwide and is a major risk factor for cardiovascular disease. People with hyperlipidemia have elevated levels of serum cholesterol and an increased risk of thrombosis. Studies have suggested that oxidized lipoproteins, such as oxidized low-density lipoprotein (oxLDL), contribute to the development of a pro-thrombotic state. In this review, we discuss our recent studies demonstrating a role for hematopoietic cell-derived tissue factor (TF) expression in the activation of coagulation and increased thrombosis associated with hyperlipidemia. In addition, we investigated the effect of simvastatin on TF expression and coagulation. We found that simvastatin reduced leukocyte TF expression, TF⁺ microparticles, and coagulation. These results and earlier studies suggest that the anti-coagulant activity of statins is due, in part, to their ability to reduce monocyte TF expression in patients with cardiovascular disease.

Monocyte tissue factor-dependent activation of coagulation in hypercholesterolemic mice and monkeys is inhibited by simvastatin

Hypercholesterolemia is a major risk factor for atherosclerosis. It also is associated with platelet hyperactivity, which increases morbidity and mortality from cardiovascular disease. However, the mechanisms by which hypercholesterolemia produces a procoagulant state remain undefined. Atherosclerosis is associated with accumulation of oxidized lipoproteins within atherosclerotic lesions. Small quantities of oxidized lipoproteins are also present in the circulation of patients with coronary artery disease. We therefore hypothesized that hypercholesterolemia leads to elevated levels of oxidized LDL (oxLDL) in plasma and that this induces expression of the procoagulant protein tissue factor (TF) in monocytes. In support of this hypothesis, we report here that oxLDL induced TF expression in human monocytic cells and monocytes. In addition, patients with familial hypercholesterolemia had elevated levels of plasma microparticle (MP) TF activity. Furthermore, a high-fat diet induced a time-dependent increase in plasma MP TF activity and activation of coagulation in both LDL receptor-deficient mice and African green monkeys. Genetic deficiency of TF in bone marrow cells reduced coagulation in hypercholesterolemic mice, consistent with a major role for monocyte-derived TF in the activation of coagulation. Similarly, a deficiency of either TLR4 or TLR6 reduced levels of MP TF activity. Simvastatin treatment of hypercholesterolemic mice and monkeys reduced oxLDL, monocyte TF expression, MP TF activity, activation of coagulation, and inflammation, without affecting total cholesterol levels. Our results suggest that the prothrombotic state associated with hypercholesterolemia is caused by oxLDL-mediated induction of TF expression in monocytes via engagement of a TLR4/TLR6 complex.

Pharmacological actions of statins: a critical appraisal in the management of cancer

Statins, among the most commonly prescribed drugs worldwide, are cholesterol-lowering agents used to manage and prevent cardiovascular and coronary heart diseases. Recently, a multifaceted action in different physiological and pathological conditions has been also proposed for statins, beyond anti-inflammation and neuroprotection. Statins have been shown to act through cholesterol-dependent and -independent mechanisms and are able to affect several tissue functions and modulate specific signal transduction pathways that could account for statin pleiotropic effects. Typically, statins are prescribed in middle-aged or elderly patients in a therapeutic regimen covering a long life span during which metabolic processes, aging, and concomitant novel diseases, including cancer, could occur. In this context, safety, toxicity, interaction with other drugs, and the state of health have to be taken into account in subjects treated with statins. Some evidence has shown a dichotomous effect of statins with either cancer-inhibiting or -promoting effects. To date, clinical trials failed to demonstrate a reduced cancer occurrence in statin users and no sufficient data are available to define the long-term effects of statin use over a period of 10 years. Moreover, results from clinical trials performed to evaluate the therapeutic efficacy of statins in cancer did not suggest statin use as chemotherapeutic or adjuvant agents. Here, we reviewed the pharmacology of the statins, providing a comprehensive update of the current knowledge of their effects on tissues, biological processes, and pathological conditions, and we dissected the disappointing evidence on the possible future use of statin-based drugs in cancer therapy.

Macrovascular thrombosis is driven by tissue factor derived primarily from the blood vessel wall

Leukocytes and leukocyte-derived microparticles contain low levels of tissue factor (TF) and incorporate into forming thrombi. Although this circulating pool of TF has been proposed to play a key role in thrombosis, its functional significance relative to that of vascular wall TF is poorly defined. We tested the hypothesis that leukocyte-derived TF contributes to thrombus formation in vivo. Compared to wild-type mice, mice with severe TF deficiency (ie, TF–/–, hTF-Tg+, or “low-TF”) demonstrated markedly impaired thrombus formation after carotid artery injury or inferior vena cava ligation. A bone marrow transplantation strategy was used to modulate levels of leukocyte-derived TF. Transplantation of low-TF marrow into wild-type mice did not suppress arterial or venous thrombus formation. Similarly, transplantation of wild-type marrow into low-TF mice did not accelerate thrombosis. In vitro analyses revealed that TF activity in the blood was very low and was markedly exceeded by that present in the vessel wall. Therefore, our results suggest that thrombus formation in the arterial and venous macrovasculature is driven primarily by TF derived from the blood vessel wall as opposed to leukocytes.

Effects of HMG-CoA reductase inhibitors on coagulation and fibrinolysis processes

Recent large clinical trials have demonstrated that HMG-CoA reductase inhibitors, or statins, markedly reduce morbidity and mortality when used in the primary and secondary prevention of cardiovascular disease. It has been established that the benefits of statin therapy in cardiovascular disease can be explained not only by the lipid-lowering potential of statins but also by nonlipid-related mechanisms (so-called "pleiotropic effects") that contribute to the positive effect of statins on the incidence of cardiovascular events. The coagulation and fibrinolytic systems are two separate but reciprocally linked enzyme cascades that regulate the formation and breakdown of fibrin. Numerous studies have demonstrated that disturbances of coagulation and fibrinolysis contribute to the development and progression of atherosclerosis, and that they affect the incidence of atherosclerosis-related clinical events. High plasma levels or activities of fibrinogen, factor VII, factor VIII, von Willebrand factor (vWF), soluble thrombomodulin, tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) are thought to be associated with increased morbidity and mortality related to cardiovascular disease. Experimental studies and many clinical studies have recently shown that statins produce favourable effects on haemostatic parameters, including those that are risk factors for cardiovascular disease. Statins diminish procoagulant activity, which is observed at different stages of the coagulation cascade, including tissue factor (TF) activity, conversion of prothrombin to thrombin and thrombin activity. In some studies, statins also reduced fibrinogen levels. By altering the levels and activities of tPA and PAI-1, statins seem to stimulate fibrinolysis. The data on the effects of combined treatment with statins and other drugs on haemostasis are rather limited. They suggest that statins combined with fibric acid derivatives, omega-3 fatty acids and 17beta-estradiol are superior to statins alone. The only two clinical studies performed in patients with acute coronary syndromes showed a relatively weak effect of statins on haemostasis in those patients. Although various statins may produce different effects on individual variables, there are no convincing data showing that differences in their physicochemical and pharmacokinetic properties significantly alter their net effect on excessive procoagulant activity. Apart from the lipid-lowering effect, statins suppress the synthesis of several important nonsterol isoprenoids derived from the mevalonate pathway, especially farnesyl and geranylgeranyl pyrophosphates, which via enhanced protein prenylation, are involved in the regulation of many cellular processes. It is presumed that the inhibitory effect of statins on the mevalonate pathway is involved in the regulation of some key steps of coagulation and fibrinolysis processes. In this way they probably regulate the synthesis of TF, tPA and PAI-1, and perhaps they also control the generation and activity of thrombin. The beneficial effects of statins on coagulation and fibrinolysis may be responsible for their ability to decrease the number of cardiovascular events. The lipid-independent effects of statins on haemostasis may contribute to the marked decrease in the incidence rates of mortality, hospitalisation and revascularisation in patients treated with these drugs.

Simvastatin inhibits expression of tissue factor in advanced atherosclerotic lesions of apolipoprotein E deficient mice independently of lipid lowering: potential role of simvastatin-mediated inhibition of Egr-1 expression and activation

Recent studies suggest that the beneficial effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (statins) in reducing cardiovascular events may in part, be independent of their capacity to lower plasma lipids. To test this hypothesis, simvastatin (50 mg/kg/d) was administered to 30-week-old apolipoprotein E deficient mice (apo E-/-) for 12, 18 and 24 weeks. In contrast to other experimental models and humans, simvastatin treatment increases plasma cholesterol levels in apo E-/- mice. Quantitative real-time polymerase chain reaction was used to quantify expression of tissue factor (TF) and monocyte chemoattractant protein-1 (MCP-1) in the aorta of each mouse. Expression of TF was reduced to 34, 24, and 13% of control levels at 12, 18 and 24 weeks, respectively, of simvastatin administration. Advanced lesions in the innominate arteries of the simvastatin treated mice had reduced levels of TF, fewer macrophages and reduced expression of early growth response-1 (Egr-1). In vitro studies in mouse macrophages demonstrated decreased lipopolysaccharide induced binding of nuclear proteins to the Egr-1 consensus DNA sequence following pretreatment with simvastatin. RNA levels for MCP-1 were reduced to 30% of control values following 24 weeks of simvastatin treatment. In conclusion, these data suggest that chronic administration of simvastatin to older apo E-/- mice can inhibit the expression of pro-thrombotic/pro-inflammatory genes within established atherosclerotic lesions via mechanisms that are independent of reductions in plasma lipids.

Role of risk factors in the modulation of tissue factor activity and blood thrombogenicity

BACKGROUND

Several studies suggest a role for an increased circulating pool of tissue factor (TF) in atherothrombotic diseases. Furthermore, certain cardiovascular risk factors, such as diabetes, hyperlipemia, and smoking, are associated with a higher incidence of thrombotic complications. We hypothesized that the observed increased blood thrombogenicity (BT) observed in patients with type 2 diabetes mellitus may be mediated via an increased circulating tissue factor activity. We have extended our study to smokers and hyperlipidemic subjects.

METHODS AND RESULTS

Poorly controlled patients with type 2 diabetes mellitus (n=36), smokers (n=10), and untreated hyperlipidemic subjects (n=10) were studied. Circulating TF was immunocaptured from plasma, relipidated, and quantified by factor Xa (FXa) generation in the presence of factor VIIa. BT was assessed as thrombus formation on the Badimon perfusion chamber. Patients with improvement in glycemic control showed a reduction in circulating TF (362+/-135 versus 243+/-74 pmol/L per min FXa, P=0.0001). A similar effect was observed in BT (15 445+/-1130 versus 12 072+/-596 microm/mm2, P=0.01). Two hours after smoking 2 cigarettes, TF was increased (217+/-72 versus 283+/-106 pmol/L per min FXa, P=0.003). Hyperlipidemic subjects showed higher TF (237+/-63 versus 195+/-44 pmol/L per min FXa, P=0.035) than healthy volunteers.

CONCLUSIONS

These findings suggest that high levels of circulating TF may be the mechanism of action responsible for the increased thrombotic complications associated with the presence of these cardiovascular risk factors. These observations strongly emphasize the usefulness of the management of the patients based on their global risk assessment.

Papel de los factores de riesgo en la trombogenicidad sanguínea y los síndromes coronarios agudos

Recent advances in basic science have linked some systemic risk factors to endothelial dysfunction which gives rise to atherosclerotic disease and triggers the progression of thrombotic complications. Superficial erosion of the stenotic plaque can be observed in one-third of acute coronary syndromes (ACS). In these cases the presence of classic risk factors such as diabetes mellitus, hypercholesterolemia and smoking favor a state of "vulnerable blood" or high risk. Increased thrombogenicity can exacerbate thrombus formation and is able to trigger an ACS. The vessel endothelium regulates contractile, mitogenic and thrombotic activities of the vessel wall. Risk factors impair both homeostasis and hemostasis of the vessel wall and promote inflammatory signals. Platelet and monocyte activation favors the expression of tissue factor (TF), thus triggering the coagulation cascade with thrombin generation and clot formation. Increased blood thrombogenicity linked to classic risk factors may be associated with circulating TF levels which are much higher than those observed in healthy subjects without risk factors. These observations not only emphasize the usefulness of aggressive management of risk factors but open a new avenue for future studies to devise therapeutic strategies to treat ACS by inhibiting TF expression.

Early statin therapy for acute coronary syndromes

OBJECTIVE

To review the clinical benefit of statins in the early management of acute coronary syndromes (ACSs) and their possible mechanisms of benefit.

DATA SOURCES

A MEDLINE search (1966-September 2001) was conducted using the following terms: pravastatin, lovastatin, simvastatin, atorvastatin, cerivastatin, fluvastatin, statins, hydroxymethylglutaryl coenzyme A reductase inhibitor, acute coronary syndromes, unstable angina, and myocardial infarction. Pertinent articles referenced in these publications were also reviewed.

STUDY SELECTION AND DATA EXTRACTION

French- and English-language human and animal studies were selected and analyzed.

DATA SYNTHESIS

In addition to their lipid-lowering properties, statins produce several nonlipid-related properties. These pleiotropic properties include improved endothelial function, reduction of inflammation at the site of the atherosclerotic plaque, inhibition of platelet aggregation, and anticoagulant effects, all of which may result in clinical benefit during ACSs. Preliminary studies and retrospective analyses of large clinical trials support the hypothesis that statins may be of benefit in ACSs. A recently published randomized, double-blind, multicenter trial evaluated the clinical impact of high-dose atorvastatin in patients with ACSs. Use of atorvastatin resulted in a decrease in a combined endpoint of cardiovascular events. Furthermore, initiation of statin therapy during hospitalization improves long-term compliance and may significantly improve clinical outcome.

CONCLUSIONS

Early use of statins in ACSs appears to decrease cardiovascular events. We believe statin therapy should be initiated early (at the latest before hospital discharge) in all patients who have been hospitalized for ACSs. Ongoing studies will clarify the benefit of these agents in ACSs, the importance of their nonlipid-lowering properties, and the optimal cholesterol-target concentrations.

Anti-thrombotic effects of atorvastatin--an effect unrelated to lipid lowering

Statins (3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) have been shown to reduce clinical events in excess of what can be explained by altering lipid profile. Statins have been shown to possess modest antioxidant and antiplatelet aggregatory effect. We postulated that statins may accordingly inhibit arterial thrombus formation. To assess the antithrombotic effects of atorvastatin, a commonly used statin, in response to an oxidant stimulus, we fed Sprague-Dawley rats either regular chow, or chow mixed with atorvastatin (1.25 mg/kg) for 10 days (n = 16 in each group). Eight rats in each group were also given oxidized low-density lipoprotein intravenously prior to the induction of thrombus. An occlusive thrombus was created in the abdominal aorta by application of Whatman paper soaked in 35% FeCl3. The time to occlusive thrombus formation was not altered by administration of oxidized low-density lipoprotein in the rats fed regular chow or chow mixed with atorvastatin. However, time to thrombosis was increased in the group given chow mixed with atorvastatin (26 +/- 4 minutes vs. 20 +/- 5 minutes, P < 0.02). To determine the mechanism of atorvastatin's antithrombotic effect, we measured the expression of endothelial constitutive nitric oxide synthase (cNOS) in rat aortas by Western analysis. The cNOS protein expression was enhanced 75% in rats fed chow with atorvastatin (P < 0.01 vs. rats fed regular chow). Plasma levels of total cholesterol and low-density lipoprotein-cholesterol were similar in all groups. This study shows that atorvastatin delays thrombus formation in arterial channels exposed to oxidant stress. This effect of atorvastatin appears to be related to increased expression of cNOS, which is known to inhibit platelet aggregation and induce vasodilatation. The effects of atorvastatin are independent of its effects on plasma cholesterol levels.

Statins reduce inflammation in atheroma of nonhuman primates independent of effects on serum cholesterol

OBJECTIVE

Some of the statin-induced reduction in cardiac events in patients with atherosclerosis may be derived from mechanisms independent of lipid lowering. This study tested in nonhuman primates whether statins can influence inflammation (indicated by vascular cell adhesion molecule-1, interleukin-1beta, tissue factor, and macrophages) and features of plaque stability (indicated by collagen and smooth muscle cells) independent of their effect on plasma cholesterol level.

METHODS AND RESULTS

Adult male cynomolgus monkeys (n=12 per group) consumed an atherogenic diet for 12 months while receiving (1) no treatment (control), (2) pravastatin (Prava, 40 mg/kg per day), or (3) simvastatin (Simva, 20 mg/kg per day). Dietary cholesterol was adjusted to equalize plasma cholesterol levels among groups. Although the intima/media ratio in the abdominal aorta did not differ among groups, drug treatment reduced inflammation and features of plaque vulnerability. Macrophage content in the lesions of statin-treated animals was lowered (2.4-fold with Prava and 1.3-fold with Simva; both P<0.001 versus control). Furthermore, lesions had approximately 2-fold less vascular cell adhesion molecule-1, interleukin-1beta, and tissue factor expression in statin-treated versus control animals (P<0.005). Lesional smooth muscle cell and collagen content was 2.1-fold greater in the Prava-treated group (P<0.001) and 1.5-fold greater in the Simva-treated group (P<0.005) than in the control group.

CONCLUSIONS

In primates, these results provide further support for the beneficial effect of statins on plaque inflammation and stability in addition to cholesterol lowering.

Rho-GTPase-dependent platelet-neutrophil interaction affected by HMG-CoA reductase inhibition with altered adenosine nucleotide release and function

Platelet activation and aggregation is considered a crucial step in the initiation and aggravation of arterial thrombosis. ADP from activated platelets is recognized as major factor in thrombus formation and is a potent stimulator of oxygen-free radical release from neutrophils. The aim of the present investigation was to determine in vitro the direct effects of statins on ATP and ADP secretion by platelets and its impact on subsequent oxidative burst activity in neutrophils. Human neutrophils and platelets were isolated from peripheral blood. Levels of platelet-derived ATP and ADP were measured by high-performance liquid chromatography, oxygen-free radical release of neutrophils was measured fluorometrically, and chemotaxis experiments were performed. Rho-GTPases were studied by Western blot analysis. Thrombin-activated platelets primed neutrophils for enhanced oxygen-free radical release on triggering with formyl-Met-Leu-Phe, reduced by cerivastatin and simvastatin treatment of platelets. The two statins decreased the amount of adenosine-derivative release in these cells. Rho-GTPases, required for the thrombin signaling in platelets and neutrophils, were decreased after coincubation with statins. Data demonstrate that inhibition of Rho-GTPases by statins inhibit platelet ADP and ATP release and the consecutive augmentation of neutrophil oxygen-free radical release. Statins affect platelet-neutrophil interactions by altering Rho-GTPase-dependent adenosine nucleotide function.

Evolving role of tissue factor and its pathway inhibitor

OBJECTIVE

To review the experimental and clinical evidence of the emerging role of tissue factor in intravascular thrombosis and to examine evidence supporting the potential use of tissue factor pathway inhibitor as an antithrombotic therapeutic agent.

DATA SOURCES AND STUDY SELECTION

A PubMed search was conducted encompassing articles in the English language relating to tissue factor and tissue factor pathway inhibitor in intravascular coagulation.

CONCLUSIONS

Tissue factor, a membrane-bound procoagulant glycoprotein, is the initiator of the extrinsic clotting cascade, which is the predominant coagulation pathway in vivo. The traditional view localizes tissue factor to extravascular sites, where it remains sequestered from circulating factor VII until vascular integrity is disrupted or until tissue factor expression is induced in endothelial cells or monocytes. This perspective has been challenged since the discovery of tissue factor antigen in plasma, on circulating microparticles, and on leukocytes in whole blood. Recently, the apparent role of tissue factor has expanded with the demonstration that this molecule also functions as a signaling receptor. Recombinant tissue factor pathway inhibitor, an analogue of the physiologic inhibitor of tissue factor, is a potent inhibitor of thrombus formation in experimental models. In summary, the tissue factor pathway initiates thrombosis in vivo. In addition to its classic tissue-bound distribution, recently discovered blood-borne tissue factor may have an important procoagulant function. Despite showing promise in early human studies, a recently completed phase 3 trial of recombinant tissue factor pathway inhibitor in severe sepsis failed to show a reduction in the primary end point of 28-day all-cause mortality. Tissue factor pathway inhibitor, however, remains a plausible therapeutic agent in other conditions of increased thrombogenicity, such as acute coronary syndromes, and further studies to examine this potential are warranted.

Improved fibrinolysis after 1-year treatment with HMG CoA reductase inhibitors in patients with coronary heart disease

The study was aimed to investigate the effect of two different statins on the levels of haemostatic variables reflecting procoagulant and fibrinolytic activity in patients with coronary heart disease (CHD), with the hypothesis that statins might beneficially modify these levels. Fifty-eight patients were randomized to treatment with atorvastatin (n=28) or simvastatin (n=30) for 1 year. The starting dose in both groups was 20 mg/day. Fasting blood samples were collected before and after 12-month treatment for determinations of fibrinogen, prothrombin fragment 1+2 (F1+2), plasma D-dimer, soluble tissue factor, tissue plasminogen activator (tPA) antigen, tPA activity, plasminogen activator inhibitor type-1 activity (PAI-1 activity) and serum D-dimer as a global test of fibrinolytic activity. In the total population, improved fibrinolytic activity was observed after 1 year with increased levels of serum D-dimer (P=.001) and tPA activity (P=.024) and a reduction in tPA antigen (P=.048). No statistically significant changes were observed in any of the measured coagulation variables. Separately examined, an improved fibrinolytic profile was seen in the atorvastatin group with a significant increase in serum D-dimer (P=.005), a borderline increase in tPA activity (P=.083) and a borderline reduction in tPA antigen (P=.069). Within the simvastatin group, a reduction in prothrombin F1+2 was observed (P=.038). The differences in changes between the groups were statistically significant only for global fibrinolysis (serum D-dimer, P=.046). In conclusion, an improved fibrinolytic profile was observed after statin treatment, most pronounced with atorvastatin. The results indicate that the drugs promote a profibrinolytic profile, and may in part explain the benefit of statin treatment rendered in the prevention of CHD.

Value or desirability of hemorheological-hemostatic parameter changes as endpoints in blood lipid-regulating trials

High levels of plasma lipids have been recognized as a major risk factor in the development and progression of atherosclerosis, and to influence hemorheological factors that may predispose to thrombotic complications. Lipid-lowering interventions have been associated with a significant reduction of morbidity and mortality. Several mechanisms have been postulated for the observed clinical effect. Serum lipid-regulating therapies may reduce cardiovascular risk not only by altering the arterial wall, improving disturbed endothelial function, atherogenesis and plaque stability, but also through their antithrombogenic effects and influence on blood flow properties associated with hyperlipidemia. In this article, we will review the recent literature and discuss the value of hemorheological-hemostatic findings as surrogate endpoints for clinical trials in dyslipidemic patients.