Muzaffer Demir

Survival of Heparins, Oral Anticoagulants, and Aspirin after the Year 2010

The conventional management of thrombotic and cardiovascular disorders is based on the use of heparin, oral anticoagulants, and aspirin. Despite remarkable progress in life sciences, these drugs still remain a challenge and a mystery to us, and their use is far from optimized. The development of low-molecular-weight heparins and the synthesis of heparinomimetics, such as the chemically synthesized pentasaccharide, represent a refined use of heparin. Additional drugs from this knowledge will continue to develop; however, none of these drugs will ever match the polypharmacology of heparin. Aspirin still remains the leading drug in the management of thrombotic and cardiovascular disorders. The newer antiplatelet drugs such as adenosine diphosphate receptor inhibitors, glycoprotein IIb/IIIa inhibitors, and other specific inhibitors have limited effects and have been tested in patients who have already been treated with aspirin. Warfarin provides a convenient and affordable approach in the long-term outpatient management of thrombotic disorders. The optimized use of these drugs still remains as the approach of choice to manage thrombotic disorders. The new anticoagulant targets, including specific sites in the hemostatic network such as tissue factor, individual clotting factors (IIa, VIIa, IXa, Xa, XIIa, and XIIIa), recombinant forms of serpins (antithrombin, heparin cofactor II, and tissue factor pathway inhibitors), recombinant activated protein C, thrombomodulin, and site-specific serine protease inhibitor complexes have also been developed. There is a major thrust on the development of orally bioavailable anticoagulant drugs (anti-Xa and anti-IIa agents), which are slated to replace oral anticoagulants. Both the anti-factor Xa and antithrombin agents have been developed for oral use and have provided impressive clinical outcomes in sponsor trials for the postsurgical prophylaxis of venous thrombosis; however, safety concerns related to liver enzyme elevations and thrombosis rebound have been reported with their use. For these reasons, the U.S. Food and Drug Administration did not approve the orally active antithrombin agent ximelagatran for several indications. The synthetic pentasaccharide (fondaparinux) has undergone an aggressive clinical development. Unexpectedly, fondaparinux also produced major bleeding problems at minimal dosages. Fondaparinux represents only one of the multiple pharmacologic effects of heparins. Thus, its therapeutic index will be proportionately narrower. The newer antiplatelet drugs have added a new dimension in the management of thrombotic disorders. The favorable clinical outcomes with aspirin and clopidogrel have validated cyclooxygenase (COX)-1 and P2Y (12) receptors as targets for new drug development. Prasugrel, a novel thienopyridine, cangrelor, and AZD 6140 represent newer P2Y (12) antagonists. Cangrelor and AZD 6140 are direct inhibitors, whereas prasugrel requires metabolic activation. Though clinically effective, recent results have prompted a closure of a large clinical trial with prasugrel due to bleeding. The newer anticoagulant and antiplatelet drugs are attractive for several reasons; however, none of these are expected to replace the conventional drugs in polytherapeutic approaches. Heparins, warfarin, and aspirin will continue to play a major role in the management of thrombotic and cardiovascular disorders beyond 2010.

Inflammatory pseudotumor of the spleen with EBV positivity: report of a case

Inflammatory pseudotumor (IPT) of the spleen is a rare benign tumor with unknown etiology. It causes problems in the diagnosis because of mimicking some hematopoetic malignancies. Here we report the case of a 36‐yr‐old woman complaining of nausea and insomnia. Laboratory investigations were limited to increase of leukocyte and thrombocyte count. Ultrasonography and magnetic resonance (MR) imaging showed circumscribed solid lobulated mass, measuring about 6.5 cm in diameter, located in the dorsal region of the spleen. Splenectomy was performed with the differential diagnosis including hamartoma and lymphoma of the spleen. Histological examination of the sharply demarcated splenic mass consisted of myofibroblasts and admixture of inflammatory cells. Immunohistochemistry and in situ hybridization were performed. IPT of the spleen was diagnosed. Epstein–Barr virus (EBV) was detected in the tumor by in situ hybridization. This rare entity is presented because of its clinical, radiological and pathological difficulties in the differential diagnosis.

Increased platelet activation markers in rheumatoid arthritis: Are they related with subclinical atherosclerosis?

Atherosclerotic cardiovascular mortality is increased in rheumatoid arthritis (RA) patients. We evaluated the association of inflammatory response with platelet, endothelial, coagulation activation parameters; and subclinical atherosclerosis in RA patients. We included 27 RA patients (21 female; six male) and 19 healthy subjects (14 female; five male). Disease activity score (DAS28) in RA patients was calculated; and patients were divided into two groups as active and inactive. Flow cytometry was used to determine platelet CD62P expression, platelet microparticles (PMP), platelet-monocyte (PMC) and platelet-neutrophil complexes (PNC). Plasma E-selectin, thrombin-antithrombin (TAT) complex, and serum sCD40L levels were determined by ELISA. The intima-media thickness (IMT) of carotid arteries was determined by B-mode ultrasonography. In RA patients, platelet CD62P expression (p < 0.001), PMC (p = 0.037) and sCD40L (p < 0.001) levels were increased when compared to the control group. PNC (p = 0.07) and TAT levels (p = 0.1) were non-significantly higher, and PMP level (p = 0.075) was nonsignificantly lower in RA patients. Soluble E-selectin level was significantly higher in the active RA group than in the inactive RA group (p = 0.009). There was no correlation between carotid IMT and activity markers, the evaluated parameters (p > 0.05).The increase in markers of active platelets, CD62P and sCD40L, and PMC levels might be associated with the increased cardiovascular mortality in RA. Nevertheless, none of these parameters were associated with carotid IMT: this suggests that one cross-sectional value might not be a good marker for atherosclerosis.

Low Leptin Levels in Migraine: A Case Control Study

Background.— Obesity has been shown to be a risk factor for transformation of episodic migraine to chronic form, and adipocytokines have been implicated to modulate some of the cytokins such as interleukin‐6 and tumor necrosis factor, which also act in the neurogenic inflammation in migraine. The aim of the study was to assess leptin levels, one of the adipocytokines, in headache‐free period of migraine patients and investigate its relation to vascular risk factors.

Factor V Leiden Mutation and Other Thrombophilia Markers in Childhood Ischemic Stroke

The aim of this study was to evaluate the association between ischemic childhood stroke and thrombophilia. The prevalence of thrombophilia risk factors in 30 unrelated children with ischemic stroke were compared with 33 age-matched control subjects. Patients and control group were tested for the presence of activated protein C (APC) resistance, antiphospholipid antibodies (APLA), increased factor VIII levels, and for the deficiency of protein C (PC), protein S (PS), and antithrombin. When APCR was detected in patients or in controls, factor V Leiden (FVL) mutation was also tested. Seventeen of 30 patients (56.6%) had at least one thrombophilia marker compared with only 5 of 33 control subjects (15.1%). Three children with ischemic stroke (10%) were affected with a combination of two or more thrombophilia markers whereas none of the children in the control group had a combination of risk factors. Seven of 30 children with ischemic stroke (23.3%) and one of 33 control subjects (3.03%) had APC resistance and in all of them FVL mutation were found. The prevalence of FVL mutation was higher among pediatric stroke patients than among control subjects (p < 0.05). None of the patients but one child from the control group (3.03%) had PS deficiency. Antithrombin and PC deficiencies and the presence of APLA and increased factor VIII levels were more frequent in the pediatric stroke patients than in controls but the difference was not statistically significant (p > 0.05). These data confirm that stroke in children is commonly associated with a combination of multiple risk factors and especially the prevalence of FVL mutation is increased in children with ischemic stroke compared with control subjects.

Anticoagulant and antiprotease profiles of a novel natural heparinomimetic mannopentaose phosphate sulfate (PI-88).

Heparinomimetic mannopentaose phosphate sulfate (PI-88) (Progen Industries Ltd. Brisbane, Australia), currently developed as an anticoagulant and antiproliferative agent, mainly is composed of a pentomannan. However, tetrasaccharide and disaccharide components are also present. The molecular profile and the anticoagulant potency of PI-88 are investigated in this study. Gel permeation chromatography and polyacrylamide gel electrophoresis analyses were carried out to determine the molecular profile and separation of components of PI-88, respectively. Potentiation of antithrombin III (ATIII) and heparin cofactor-II (HC-11) activity were measured using chromogenic substrate assay. In order to determine anticoagulant and antiprcatease effects of PI-88, various global anticoagulant tests, such as the prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), Hep-test@ (Haemachem Inc., St. Louis), ecarin clotting time (ECT), activated clotting time (ACT), and thromboelastography (TEG) were used. Anti-Xa and anti-IIa activities also were measured. The effect of PI-88 on the release of tissue factor pathway inhibitor (TFPI) was performed in nonhuman primates who received PI-88 and in endothelial cell culture systems. The relative susceptibility of PI-88 to heparinase 1, protamine sulfate (PS), and platelet factor 4 (PF4) also was evaluated. The high-performance liquid chromatography profiles of PI-88 showed that its average molecular weight is approximately 2300 Da. Separation and gradient electrophoretic . patterns of PI-88 showed that it is composed of five different fractions. This agent activates HC-II through inhibiting the thrombin generation but not inhibiting ATIII. Although PI-88 produced a concentration-dependent prolongation of all of the clotting tests, ECT gave the best correlation in the dose-response curve (ECT, r2 = 0.94; TT, r2 = 0.84; APTT, r2 = 0.69). Heparinomimetic mannopentaose phosphate sulfate (PI-88) exhibited marked inhibition of FIIa, but not of FXa. Heparinase I failed to produce significant neutralization of PI-88 in all the assays used, whereas PS and PF4 partially neutralized the effects of this compound. Heparinomimetic mannopentaose phosphate sulfate (PI-88) produced fivefold increase in the TFPI levels at 15 minutes after intravenous (IV) injection to primates. The incubation of PI-88 in endothelial cell culture system also showed a strong effect on TFPI release. These results suggest that PI-88 exhibited strong antithrombotic and anticoagulant activity in addition to its known antiproliferative properties. Because of the molecular characteristics and the dual nature of the pharmacokgic action of PI-88., this agent represents an attractive pharmacotogic agent for the control of thrombotic and proliflerative disorders.

17p Deletion is associated with resistance of B-cell chronic lymphocytic leukemia cells to in vitro fludarabine-induced apoptosis

We explored the relationship between the cytogenetic/biologic characteristics of B-chronic lymphocytic leukemia (B-CLL) cells and their tendency to undergo spontaneous or fludarabine-induced apoptosis in vitro. B cells from 36 B-CLL patients were incubated with or without fludarabine for 48 h. Apoptosis was determined by two assays: annexin V staining and DNA staining. Fluorescence in situ hybridization was used for detection of trisomy 12, 11q deletion, and 17p deletion. Bcl-2 and CD38 expressions were determined by flow cytometry. Five patients had 17p deletion, 6 had trisomy 12, and another 6 had 11q deletion. B-CLL cells with 17p deletion had significant resistance to apoptosis induced by fludarabine and a slight spontaneous resistance to apoptosis. Bcl-2 and CD38 were not associated with in vitro spontaneous and fludarabine-induced apoptosis. In conclusion, 17p deletion, which causes loss of p53 gene, is associated with resistance to fludarabine-induced apoptosis in vitro. New treatment modalities should be tried in B-CLL patients with 17p deletion.

Increased circulating platelet-leucocyte complexes in patients with primary Raynaud's phenomenon and Raynaud's phenomenon secondary to systemic sclerosis : a comparative study

Platelet activation and circulating platelet–leucocyte complexes increase in vascular ischemic events and autoimmune inflammatory diseases. Platelet activation markers and platelet–leucocyte complexes were evaluated in primary Raynauds phenomenon (RP) and in RP secondary to systemic sclerosis (SSc). Whole-blood flow cytometry was utilized to quantify CD62P, platelet microparticles (PMP), platelet–monocyte complexes (PMC) and platelet–neutrophil complexes (PNC) in primary RP and in SSc patients with secondary RP. SSc patients with secondary RP had significantly higher platelet CD62P expression than primary RP patients and controls (P = 0.017 and 0.004, respectively). Primary and secondary RP patients had higher mean PMC and PNC levels than controls (all P ≤ 0.001). PMP level in SSc patients with pulmonary hypertension was significantly higher than in others (P = 0.048). All parameters were similar in SSc patients with and without digital ulcers, aspirin-users and nonusers (P > 0.05). CD62P level decreased significantly after iloprost administration in four patients with digital ulcers (16.1 ± 17.4 vs 7.4 ± 3.8%, P = 0.03). Our results suggest there is platelet–leucocyte complex formation in RP, and, despite antithrombotic therapy, platelet activation and platelet–leucocyte interaction are ongoing in SSc. This is important as it might have potential therapeutic implications with respect to using antiplatelet drugs in SSc.

Insulin resistance and high sensitivity C-reactive protein in migraine.

BACKGROUND A relationship between migraine and vascular disorders such as hypertension, stroke, and coronary ischemia has been recently reported. Insulin resistance and endothelial dysfunction, which commonly underlies these disorders, have not been widely investigated in migraine patients. In this study, we aimed to investigate the existence of insulin resistance and endothelial dysfunction, and their relationship to vascular risk factors in patients with migraine. METHODS We evaluated insulin resistance and high-sensitivity C-reactive protein (hs-CRP), a marker of endothelial dysfunction, in 60 migraine patients and 25 healthy control subjects. Multiple analysis of covariance test was used to adjust for known confounding factors that can influence insulin metabolism and endothelial function, such as obesity, blood pressure, and lipid parameters. RESULTS Insulin resistance, as measured homeostasis model assessment (HOMA)-R levels, was significantly higher in the migraine group (p<0.001). After adjustment for confounding variables, the relationship between migraine and the HOMA-R levels remained significant (p<0.001). The hs-CRP levels did not differ between the migraine and control groups. CONCLUSIONS Our data show that insulin resistance is present in migraine patients. Endothelial dysfunction is not found during the headache-free period. Further studies are needed to explain the role of insulin resistance in migraine pathogenesis.

Primary angiosarcoma of the spleen: In vivo and in vitro MRI findings

Primary splenic angiosarcomas are extremely rare tumors with very poor prognosis. These tumors, highly aggressive and lethal, present with widespread metastatic disease or splenic ruptures. The possibility to lengthen the survival by splenectomy before the development of splenic rupture makes an early radiological diagnosis a necessity. Multimodality imaging findings of a patient with splenic angiosarcoma is presented. In vivo and in vitro magnetic resonance imaging (MRI) features of the spleen are compared to macro- and micropathological findings.