Bashir A. Lwaleed

Tissue factor pathway inhibitor: structure, biology and involvement in disease

Tissue factor (TF)‐initiated coagulation plays a significant role in the pathophysiology of many diseases, including cancer and inflammation. Tissue factor pathway inhibitor (TFPI) is a plasma Kunitz‐type serine protease inhibitor, which modulates initiations of coagulation induced by TF. In a factor (F) Xa‐dependent feedback system, TFPI binds directly and inhibits the TF–FVII/FVIIa complex. Normally, TFPI exists in plasma both as a full‐length molecule and as variably carboxy‐terminal truncated forms. TFPI also circulates in complex with plasma lipoproteins. The levels and the dual inhibitor effect of TFPI on FXa and TF–FVII/FVIIa complex offers insight into the mechanisms of various pathological conditions triggered by TF. The use of selective pharmacological inhibitors has become an indispensable tool in experimental haemostasis and thrombosis research. In vivo administration of recombinant TFPI (rTFPI) in an experimental animal model prevents thrombosis (and re‐thrombosis after thrombolysis), reduces mortality from E. coli‐induced‐septic shock, prevents fibrin deposition on subendothelial human matrix and protects against disseminated intravascular coagulation (DIC). Thus, TFPI may play an important role in modulating TF‐induced thrombogenesis and it may also provide a unique therapeutic approach for prophylaxis and/or treatment of various diseases. In this review, we consider structural and biochemical aspects of the TFPI molecule and detail its inhibitory mechanisms and therapeutic implications in various disease conditions. Copyright

Pre-eclampsia: Relationship between coagulation, fibrinolysis and inflammation

Pre-eclampsia (PE) is a multi-system disorder of human pregnancy, characterised by hypertension and proteinuria. Although the pathogenesis of PE is not fully understood, predisposition to endothelial dysfunction is thought to play a crucial part. Despite intensive research there is no reliable test for screening purposes or to inform decision making towards effective treatment for PE. Understanding the link between PE, abnormal haemostatic activation and inflammation may help to elucidate some of the patho-physiology of the disease; primary preventative measures and targeted therapies at an early stage of the disease could then be considered. In the present paper we discuss potential causal links between PE, haemostasis and inflammation. The potential implications of such interaction on the pathogenesis of PE are also addressed.

New anticoagulants: how to deal with treatment failure and bleeding complications

Conventional anticoagulants have proven efficacy in the management of thromboembolism. Their adverse effects and a narrow therapeutic window, necessitating regular need for monitoring, however, have long been an incentive for the development of safer anticoagulants without compromising efficacy. Over the last decade or so several new parenteral and oral anticoagulants have been launched with efficacy comparable with conventional agents. From fondaparinux to its long acting derivative idraparinux, and the factor Xa inhibitor rivaroxaban to the direct thrombin inhibitor dabigatran, the advent of new anticoagulants is radically changing anticoagulation. For conventional anticoagulants, despite their shortcomings, effective methods of reversing their anticoagulant effects exist. Moreover, strategies to deal with the occurrence of fresh thrombotic events in the face of therapeutic anticoagulation with the conventional agents have also been addressed. Nevertheless, for the new anticoagulants, the optimal management of these complications remains unknown. This review explores these issues in the light of current evidence.

The biology and tumour-related properties of monocyte tissue factor.

Tissue factor (TF, coagulation factor III, CD142) is not only the main physiological initiator of normal blood coagulation, but is also important in the natural history of solid malignancies in that it potentiates metastasis and angiogenesis and mediates outside–in signalling. TF is expressed constitutively by many tissues which are not in contact with blood and by other cells upon injury or activation; the latter include endothelial cells, tissue macrophages, and peripheral blood monocytes. It can exist encrypted and unavailable functionally in the plasma membrane and the appearance of functional TF may be due to synthesis and/or de‐encryption. Inflammatory cells often express TF and act to induce its production or de‐encryption by other cells locally and, apparently, at remote sites. Inappropriate expression of TF by endothelial cells, macrophages or monocytes is thought to be an important trigger of coagulation in various pathological conditions. Several studies have shown that measurements of monocyte TF (mTF) may provide clinically significant information, particularly in patients with malignant and inflammatory diseases. Copyright

The effects of dietary lycopene supplementation on human seminal plasma

To investigate whether lycopene levels in blood and seminal plasma increase after dietary supplementation with a natural source of the compound, and whether any potential increase of lycopene levels in semen translates into increased free‐radical trapping capacity in the seminal plasma.

Current Drug Therapy for Prostate Cancer: An Overview

Prostate cancer is the most common cancer amongst men in the USA and the second most common malignant cause of male death worldwide after lung cancer. The life time risk of having microscopic evidence of prostate cancer for a 50 year old man is 42%. Prostate cancer is thus becoming an increasingly significant global health problem in terms of mortality, morbidity, as well as economically. This review, discusses current medical therapeutic options for prostate cancer including traditional treatments using luteinising hormone releasing analogues (LHRH), anti-androgens and estrogen treatments, and the use of novel drugs directed against molecular targets considered important in oncogenesis and metastasis. Prostate cancer chemoprevention using 5alpha-reductase inhibitors and the role of gene therapy are also considered.

Epirubicin and meglumine ?-linolenic acid: a logical choice of combination therapy for patients with superficial bladder carcinoma

BACKGROUND Anthracyclines have been established as first-line drugs for intravesical use in the treatment of patients with superficial bladder carcinoma, although they result only in a modest reduction in tumor recurrence rates. The essential fatty acid γ-linolenic acid (GLA) also is an effective cytotoxic agent against superficial bladder carcinoma when it is applied topically. The objective of this study was to assess the efficacy of combined epirubicin and GLA with the purpose of developing a suitable model for modification of existing intravesical regimens. METHODS The human urothelial carcinoma cell lines MGH-U1 and RT112 were used in standard cytotoxicity assays and were exposed to meglumine GLA (MeGLA) and epirubicin in two-dimensional concentration matrices. A thiozolyl blue (methyl-thiazoldiphenyl tetrazolium) assay was used to determine residual cell biomass. Drug interaction was quantified by median-effect analysis software (CalcuSyn®), and the evaluation of drug uptake utilized fluorescence confocal microscopy (FCM) and flow cytometry. RESULTS MeGLA caused a significant enhancement of anthracycline uptake, viewed by FCM, from 92 fluorescence units to 222 fluorescence units (P < 0.001). Flow cytometry confirmed the increased drug uptake and showed that the mean epirubicin content per cell increased from 23 to 57 units and from 8 to 24 units for MGH-U1 and RT112 cells, respectively (99% confidence interval < 0.3). This resulted in improved cytotoxicity, and it was shown that the drugs acted synergistically with all but the highest MeGLA concentrations. CONCLUSIONS The efficacy of epirubicin was enhanced significantly when it was used in combination with most concentrations of MeGLA (< 300 μg/mL), and the two agents acted synergistically. There was a corresponding increase in epirubicin uptake by cells under these conditions. At high MeGLA concentrations, however, anthracycline solubility was compromised, and drug synergy was lost. Cancer 2003;97:71–8.

Tissue Factor: A Critical Role in Inflammation and Cancer:

A series of coordinated enzymatic reactions takes place in the body whenever blood clots. The major physiological initiator of these reactions is a membrane-bound glycoprotein known as tissue factor (TF), which is normally separated from the bloodstream by the vascular endothelium. Bleeding, caused by injury or tissue damage, activates a complex enzyme cascade as TF becomes exposed to the bloodstream. In disease states, leukocytes or the vascular endothelium may abnormally express TF to cause intravascular coagulation. The blood-coagulation cascade is also relevant to diseases such as hemophilia, in which patients are deficient in blood proteins necessary for clotting, and is linked to vascular diseases such as heart attack and stroke, in which clotting can lead to the occlusion of blood vessels. Coagulation is also activated in inflammation and cancer. In this article, we discuss characteristics of TF and review its role in inflammation and cancer.

Platelet function in pre-eclampsia

Pronounced hemostatic changes occur during pregnancy, and the balance shifts markedly in favor of hypercoagulability. Although primarily a result of a marked rise in the levels of several procoagulants and a fall in some natural anticoagulants, platelet activation also contributes to this prothrombotic tendency. Several studies have confirmed the accentuation of platelet activation in pre-eclampsia (P-EC), which remains an important obstetric complication affecting ~2 to 4% of pregnancies. Although there is still a long way to go, significant inroads have been made in the understanding of this enigmatic condition. Whereas the pathogenesis of P-EC is protean and involves a complex interplay of placental and maternal tissues, platelet activation is likely to contribute to several clinical features. Several techniques have been used to assess platelet activation in P-EC. Detection of aberrations of platelet function and activation appear to have predictive value for its diagnosis. The findings also lend support to the use of antiplatelet agents as prophylaxis in those women with a high risk of developing the condition.

Urinary tissue factor levels in patients with breast and colorectal cancer

Activation of blood coagulation is a common complication of cancer in man and experimental animals. The causes of such activation may be multifactorial, but increased production of tissue factor (TF) by the host mononuclear cells may be involved. TF is not only produced by human monocytes (mTF) and tumour cells, but is also found in urine (uTF), where measurements might be clinically important. Using a highly reproducible (intra‐assay CV 2·3 per cent and inter‐assay CV 8·1 per cent) one‐stage kinetic chromogenic assay (KCA) developed by this group, uTF levels were measured in controls [healthy volunteers (n = 57), patients with renal stones and a normal ESR (n = 30)] and in patients with benign and malignant diseases of the breast (n = 94) and large bowel (n = 62). Each benign disease group was sub‐divided into inflammatory and non‐inflammatory categories. There were no significant differences between the controls and the benign non‐inflammatory groups, so they were unified for further analysis. Malignant groups, irrespective of tumour types, showed significantly higher uTF levels than controls (p < 0·001 for breast and p < 0·01 for large bowel). Similarly, breast and colorectal benign inflammatory groups showed significant increases over controls (p < 0·01 and p < 0·001, respectively). Patients with malignant disease showed uTF activity above the upper quartile range of the normal control group for breast, 77·3 per cent, and large bowel, 73 per cent. uTF levels were related to histological tumour grading and were higher in non‐surviving patients. In conclusion, uTF levels are raised in malignant and inflammatory disease compared with controls and patients with non‐inflammatory conditions. uTF levels may reflect tumour progression. Copyright