Polysulfated xanthones: multipathway development of a new generation of dual anticoagulant/antiplatelet agents.

A multipathway strategy was used to evaluate the in vitro and in vivo antithrombotic effects of a new synthetic family of sulfated small molecules. Polysulfated xanthonosides showed highly effective anticoagulation effects in vitro, both in plasma (clotting times) and in whole human blood (thromboelastography), as well as in vivo (ip administration, mice). Physicochemical properties were assessed for mangiferin heptasulfate (7), which showed high solubility and stability in water and in human plasma and no putative hepatotoxicity in vivo. Mangiferin heptasulfate (7) was found to be a direct inhibitor of FXa, while persulfated 3,6-(O-ß-glucopyranosyl)xanthone (13) acted as a dual inhibitor of FXa (directly and by antithrombin III activation). By impedance aggregometry, compounds 7 and 13 exhibited the antiplatelet effect by inhibition of both arachidonic acid and ADP-induced platelet aggregation. Dual anticoagulant/antiplatelet agents, such as sulfated xanthonosides 7 and 13, are expected to lead to a new therapeutic approach for the treatment of both venous and arterial thrombosis.

Dual anticoagulant/antiplatelet persulfated small molecules.

A new series of persulfated compounds was synthesized and assayed for in vitro anticoagulant and antiplatelet activities, which may be useful in the treatment of both venous and arterial thrombosis. Persulfation of polyphenolic components of wine, coumarins and other structurally diverse small molecules was achieved with triethylamine-sulphur trioxide adduct. The derivatives were highly effective in increasing the APTT, being trans-resveratrol 3-ß-D-glucopyranoside persulfate (15) the most potent (APTT2=1.5×10(-4) M), and were able to completely block the clotting process at the highest concentration. Compound 15 showed good stability in human plasma and anticoagulation effects in whole blood. trans-Resveratrol 3-ß-D-glucopyranoside persulfate (15) and a series of polysulfated oligoflavonoids (1-4) also exhibited antiplatelet activity by inhibition of arachidonic acid and ADP-induced platelet aggregation.

Flavonoids with an oligopolysulfated moiety: a new class of anticoagulant agents.

Polysulfated (oligo)flavonoids were synthesized and assayed for their in vitro and in vivo anticoagulant activities. The approach was based on molecular hybridization of two classes of anticoagulants, sulfated polysaccharides and sulfated flavonoids. The synthesis was optimized using microwave-assisted sulfation with triethylamine-sulfur trioxide. The obtained polysulfated flavonosides were highly effective in increasing clotting times and able to completely block the clotting process, in contrast to their corresponding aglycones. The thromboelastography proved that polysulfated flavonosides possess good whole blood anticoagulation activity. The following structure-activity relationships were found: 3-O-rutinosides (10, 13) were direct inhibitors of FXa, while 7-O-rutinosides (7, 8) showed inhibition of FXa by ATIII activation. Furthermore, compounds 7 and 13 were stable in plasma and active in vivo and preliminary toxicity studies would lead us to rule out acute side effects. From the overall results, the polysulfated flavonosides showed the potential as new effective and safe agents for anticoagulant therapy.

Detection of HIV-1 subtype G using Cobas Ampliscreen test.

A nucleic acid amplification test for detection of HIV-1 RNA was designed for screening pools of human plasma. This test achieves a similar level of sensitivity for group M subtypes, but few samples of subtype G and none of its CRFs had been tested, which are the most relevant in Portugal. We found that the test is effective in detecting HIV-1 subtypes and has an analytical sensitivity similar to B subtype.

High prevalence of combined thrombophilic abnormalities in patients with inflammatory bowel disease.

INTRODUCTION: A hypercoagulable state has been recognized in patients with inflammatory bowel disease. OBJECTIVE: The aim of this study was to determine the frequency of single and combined thrombophilic abnormalities in patients from northern Portugal with Crohn's disease or ulcerative colitis, without a history of thrombosis. METHODS A cross-sectional study involving 116 patients (42 with ulcerative colitis, 74 with Crohn's disease), and 141 randomly chosen asymptomatic blood donors was carried out. Prothrombotic variables and genetic abnormalities were assessed. RESULTS: The prevalence of single prothrombotic abnormalities (only one alteration) in inflammatory bowel disease patients was higher than in the reference population (26% and 18%, respectively; P < 0.02). The allelic frequency of genetic polymorphisms was higher in Crohn's disease and ulcerative colitis for MTHFR C677T, ACE Del and PAI-1 4G (P < 0.001) than in the reference population. The prevalence of combined thrombophilic abnormalities (at least two alterations) in both Crohn's disease and ulcerative colitis was also higher (22% and 21%, respectively) than in the reference population (9%; P < 0.01). These differences were not related to age or gender; however, in Crohn's disease the frequency of two or more abnormalities was related to disease activity (odds ratio 3.0 [1.3-6.7]). CONCLUSION: Higher prevalences of single and combined thrombophilic defects were found in inflammatory bowel disease patients, factors that could be involved in the disease pathogenesis.