iloprost and Thrombophilia

More than a decade has gone by since the detailed clinical description of the Antiphospholipid (Hughes) Syndrome. Because of the wide spectrum of manifestations, virtually any physician may encounter patients with this potentially treatable condition. Because of limited controlled, prospective data, current therapy remains empirical and directed at coagulation mechanisms, immune mechanisms, or both. There is now good evidence that patients with antiphospholipid-associated thrombosis will be subject to recurrences and require prophylactic therapy. Although most authorities agree about the efficacy of warfarin alone or warfarin plus low-dose aspirin in preventing recurrences of venous and arterial thrombosis, there is still doubt regarding the intensity and duration of warfarin therapy. Steroids and immunosuppressive drugs have not provided long-term benefit. Controlled clinical trials of the treatment of pregnant women with antiphospholipid antibody demonstrated that prednisolone is ineffective, and possibly detrimental, in treatment of recurrent pregnancy loss and that heparin plus low-dose aspirin is beneficial.

Topics: Abortion, Habitual; Antibodies, Antiphospholipid; Anticoagulants; Antiphospholipid Syndrome; Aspirin; Autoimmune Diseases; Contraindications; Drug Therapy, Combination; Female; Heparin; Humans; Iloprost; Immunoglobulins, Intravenous; Immunosuppressive Agents; Male; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Prospective Studies; Recurrence; Thrombophilia; Thrombosis; Warfarin

Vasodilator-stimulated phosphoprotein (VASP) is phosphorylated and dephosphorylated consequent to increases and decreases in cyclic nucleotide levels. Monitoring changes in VASP phosphorylation is an established method for indirect measurement of cyclic nucleotides. Here we describe the use of an innovative cocktail, VASPFix, which allows sensitive and reproducible measurement of phosphorylated VASP (VASP-P) in a simple, single-step procedure using cytometric bead technology. Frozen VASPFix-treated samples are stable for at least six months prior to analysis. We successfully used VASPFix to measure VASP-P in platelets in both platelet-rich plasma and blood in response to compounds that increase (dibutyryl cAMP, adenosine, iloprost, PGE1) and decrease (ADP, PGE1) cAMP, and to determine the effects of certain receptor antagonists on the results obtained. The change in VASP-P brought about by adding ADP to PGE1-stimulated platelets is a combination of the effect of ADP at the P2Y12 receptor and of PGE1 at both IP and EP3 receptors. For iloprost-stimulated platelets EP3 receptors are not involved. A procedure in which iloprost, ADP and VASPFix were used to determine effectiveness of clopidogrel and prasugrel in patients was compared with an established commercial procedure that uses PGE1 and ADP; the latter produced higher platelet reactivity values that were the result of PGE1 interacting with platelet EP3 receptors. We conclude that VASPFix can be used both as a research tool and for clinical investigations and provides better specificity for P2Y12 receptor inhibition. The latter confers a distinct advantage over existing methods used to monitor effects of P2Y12 antagonists on platelet function.

Topics: Adenosine; Adenosine Diphosphate; Alprostadil; Biomarkers, Pharmacological; Blood Platelets; Bucladesine; Cell Adhesion Molecules; Cells, Cultured; Clopidogrel; Cyclic AMP; Humans; Iloprost; Microfilament Proteins; Phosphoproteins; Phosphorylation; Piperazines; Platelet Aggregation; Platelet Function Tests; Prasugrel Hydrochloride; Purinergic P2Y Receptor Antagonists; Reproducibility of Results; Sensitivity and Specificity; Thiophenes; Thrombophilia; Ticlopidine

There is concern that cyclooxygenase (COX)-2 inhibitors may promote atherothrombosis by inhibiting vascular formation of prostacyclin (PGI2) and an increased thrombotic risk of COX-2 inhibitors has been reported. It is widely accepted that the prothrombotic effects of COX-2 inhibitors can be explained by the removal of platelet-inhibitory PGI2. Using microarray chip technology, we have previously demonstrated that thrombomodulin (TM) mRNA is upregulated in cultured human coronary artery smooth muscle cells by the stable prostacyclin mimetic iloprost. This study is the first to demonstrate a stimulation of the expression of functionally active thrombomodulin in human smooth muscle cells by prostaglandins, endogenously formed via the COX-2 pathway. Because TM is an important inhibitor of blood coagulation, these findings provide a novel platelet-independent mechanism to explain the prothrombotic effects of COX-2 inhibitors. The full text of this article is available online at http://circres.ahajournals.org.

Topics: Alprostadil; Blood Coagulation; Bucladesine; Carotid Artery Diseases; Carotid Artery, Internal; Cells, Cultured; Colforsin; Coronary Vessels; Culture Media, Serum-Free; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Diclofenac; Dinoprostone; Epoprostenol; Etoricoxib; Gene Expression Profiling; Gene Expression Regulation; Humans; Iloprost; Isoquinolines; Mammary Arteries; Membrane Proteins; Models, Biological; Myocytes, Smooth Muscle; Oligonucleotide Array Sequence Analysis; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Pyridines; Receptors, Prostaglandin; Receptors, Prostaglandin E; Receptors, Prostaglandin E, EP3 Subtype; RNA, Messenger; Saphenous Vein; Second Messenger Systems; Sulfonamides; Sulfones; Tetradecanoylphorbol Acetate; Thrombomodulin; Thrombophilia; Vasodilator Agents

Selective inhibitors of cyclooxygenase-2 (Cox-2) are reported to cause cardiovascular side effects in patients at risk. However, direct proof of prothrombotic effects of these drugs is lacking. We investigated in the microcirculation in vivo whether selective inhibition of Cox-2 induces platelet activation.. The behavior of fluorescence-labeled human platelets was studied in hamster arterioles (dorsal skinfold chamber) by intravital microscopy. Transient platelet-vessel wall interactions (PVWIs), firm platelet adhesion to the vessel wall, and vessel occlusion after FeCl3-induced wall injury were analyzed as platelet activation parameters. In vitro experiments in human umbilical vein endothelial cells (HUVECs) were performed to assess specific effects of Cox-2 inhibition on platelet adhesion under shear stress (16 dyn/cm2) and on endothelial release of 6-ketoprostaglandin (PG) F(1alpha). Selective inhibition of Cox-2 (NS-398, 0.5 mg/kg) increased platelet adhesion to the vessel wall in vivo (11.9+/-3.9 platelets/mm2; controls, 1.4+/-1.4 platelets/mm2, P<0.05) and platelet adhesion after ADP stimulation in vitro. PVWIs were significantly enhanced in NS-398-treated animals, which were reduced by platelet pretreatment with aspirin (5 mg/kg) or iloprost (1 nmol/L). Inhibition of Cox-2 reduced levels of 6-keto-PGF1alpha in vivo and in HUVEC supernatants. Time to occlusion after vessel wall injury was significantly shortened by NS-398 (125.4+/-13.6 seconds in NS-398-treated animals versus 270.8+/-46 seconds in controls; P<0.01).. Selective inhibition of Cox-2 reduces 6-keto-PGF(1alpha) endothelial release, increases PVWIs, and increases firm platelet adhesion in hamster arterioles. Moreover, it leads to faster occlusion of damaged microvessels. Thus, selective inhibition of Cox-2 may trigger thrombotic events by diminishing the antiplatelet properties of the endothelium.

Topics: 6-Ketoprostaglandin F1 alpha; Adenosine Diphosphate; Animals; Arterioles; Aspirin; Cells, Cultured; Cricetinae; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Endothelial Cells; Endothelium, Vascular; Humans; Iloprost; Membrane Proteins; Mesocricetus; Nitrobenzenes; Platelet Activation; Platelet Adhesiveness; Platelet Aggregation Inhibitors; Prostaglandin-Endoperoxide Synthases; Skin Window Technique; Sulfonamides; Thrombophilia; Umbilical Veins

Livedoid vasculopathy is characterized by early, focal painful purpuric lesions of the lower skin extremities without histologic finding of small vessel vasculitis.. A 38-year-old man was seen in our unit for painful purpuric lesions of both feet localized on toes and external sides. Skin biopsy showed dermic vessel thrombosis and endothelial cell proliferation. Lupus anticogulant antibody was positive in association with a heterozygous factor V (Leiden) gene mutation (G1691A). Anticoagulation failed to relieve pain and cutaneous lesions. Intravenous iloprost, a prostacylcin analogous (Ilomedine) was dramatically and rapidly effective in our patient.. Livedoid vasculopathy is a cutaneous affection related to vascular thrombotic events in which thrombophilia plays a central role. Iloprost might be an interesting alternative treatment of painful purpuric lesions when anticoagulant treatments are ineffective.

Topics: Adult; Anticoagulants; Foot; Humans; Iloprost; Infusions, Intravenous; Male; Pain; Skin Diseases, Vascular; Thrombophilia; Treatment Outcome; Vasodilator Agents

Buerger's disease or thromboangiitis obliterans is a disorder of unknown etiology which affects young heavy smokers, mainly of male sex; it is not clear why this disease afflicts only a little number of heavy smokers. Studies about genetic predisposition, autoimmune phenomena and platelet function have been performed in order to search additional etiologic factors without finding significant alterations. Recently some cases of Buerger's disease in association with hypercoagulable states have been described. The authors reported ten subjects affected by Buerger's disease, who have undergone to a clotting process evaluation. We have found 3 cases with fasting hyperhomocysteinemia in association with low level of plasma folate, 3 cases with high value of lipoprotein(a) (in 1 subject in association with IgG anticardiolipin antibody positivity), 1 case with IgM anticardiolipin antibody positivity. These findings, along with literature data, induce to hypothesize that hypercoagulable states may favour the clinical expression of Buerger's disease.

Topics: Adjuvants, Immunologic; Adult; Angiography; Aspirin; Female; Humans; Hyperhomocysteinemia; Iloprost; Male; Platelet Aggregation Inhibitors; Prognosis; Randomized Controlled Trials as Topic; Risk Factors; Smoking Cessation; Thromboangiitis Obliterans; Thrombophilia; Vasodilator Agents