Rationale: Myocardial infarction and stroke are leading causes of morbidity/mortality. The typical underlying pathology is the formation of thrombi/emboli and subsequent vessel occlusion. Systemically administered fibrinolytic drugs are the most effective pharmacological therapy. However, bleeding complications are relatively common and this risk as such limits their broader use. Furthermore, a rapid non-invasive imaging technology is not available. Thereby, many thrombotic events are missed or only diagnosed when ischemic damage has already occurred.Objective: Design and preclinical testing of a novel 'theranostic' technology for the rapid non-invasive diagnosis and effective, bleeding-free treatment of thrombosis.Methods and Results: A newly created, innovative theranostic microbubble combines a recombinant fibrinolytic drug, an echo-enhancing microbubble and a recombinant thrombus-targeting device in form of an activated-platelet-specific single-chain antibody. After initial in vitro proof of functionality, we tested this theranostic microbubble both in ultrasound imaging and thrombolytic therapy using a mouse model of ferric-chloride-induced thrombosis in the carotid artery. We demonstrate the reliable highly sensitive detection of in vivo thrombi and the ability to monitor their size changes in real time. Furthermore, these theranostic microbubbles proofed to be as effective in thrombolysis as commercial urokinase but without the prolongation of bleeding time as seen with urokinase.Conclusions: We describe a novel theranostic technology enabling simultaneous diagnosis and treatment of thrombosis, as well as monitoring of success or failure of thrombolysis. This technology holds promise for major progress in rapid diagnosis and bleeding-free thrombolysis thereby potentially preventing the often devastating consequences of thrombotic disease in many patients.

Rationale: Fibrinolysis is a valuable alternative for the treatment of myocardial infarction when percutaneous coronary intervention is not available in a timely fashion. For acute ischemic stroke, fibrinolysis is the only treatment option with a very narrow therapeutic window. Clinically approved thrombolytics have significant drawbacks, including bleeding complications. Thus their use is highly restricted, leaving many patients untreated. Objective: We developed a novel targeted fibrinolytic drug that is directed against activated platelets. Methods and Results: We fused single-chain urokinase plasminogen activator (scuPA) to a small recombinant antibody (scFv SCE5 ), which targets the activated form of the platelet–integrin glycoprotein IIb/IIIa. Antibody binding and scuPA activity of this recombinant fusion protein were on par with the parent molecules. Prophylactic in vivo administration of scFv SCE5 –scuPA (75 U/g body weight) prevented carotid artery occlusion after ferric chloride injury in a plasminogen-dependent process compared with saline ( P <0.001), and blood flow recovery was similar to high-dose nontargeted urokinase (500 U/g body weight). Tail bleeding time was significantly prolonged with this high dose of nontargeted urokinase, but not with equally effective targeted scFv SCE5 –scuPA at 75 U/g body weight. Real-time in vivo molecular ultrasound imaging demonstrates significant therapeutic reduction of thrombus size after administration of 75 U/g body weight scFv SCE5 –scuPA as compared with the same dose of a mutated, nontargeting scFv–scuPA or vehicle. The ability of scFv SCE5 –scuPA to lyse thrombi was lost in plasminogen-deficient mice, but could be restored by intravenous injection of plasminogen. Conclusions: Targeting of scuPA to activated glycoprotein IIb/IIIa allows effective thrombolysis and the potential novel use as a fibrinolytic agent for thromboprophylaxis without bleeding complications.

Zusammenfassung Hintergrund Therapierefraktäre Arthritiden sind ein häufiges Problem im rheumatologischen Alltag und können eine differentialdiagnostische Herausforderung darstellen. Chronische Infektionen durch Tropheryma whipplei (T. whipplei) sollten in diesen Fällen bedacht werden. Ziel der Arbeit Anhand von 5 klinischen Fällen werden in dieser fallbasierten Übersichtsarbeit die diagnostischen und therapeutischen Prinzipien im Management der chronischen T.-whipplei-Infektion erläutert. Ergebnis Der Morbus Whipple ist eine infektiöse Multisystemerkrankung, die durch das Bakterium T. whipplei ausgelöst wird. Typischerweise manifestiert sich die Erkrankung mit Arthralgien, Gewichtsverlust und Diarrhoen. Die Gelenkmanifestationen gehen den gastrointestinalen Krankheitserscheinungen häufig mehrere Jahre voraus. Neben systemischen Manifestationen (Morbus Whipple) kann T. whipplei auch zu lokalisierten Infektionen der Gelenke ohne gastrointestinale Beteiligung führen. Die Gelenkmanifestationen systemischer und lokalisierter T.-whipplei-Infektionen werden fälschlicherweise häufig als Zeichen verschiedener autoimmunologischer Arthritiden gedeutet. Diskussion Bei der Abklärung therapierefraktärer Arthritiden sollte an einen Morbus Whipple und lokalisierte Gelenkinfektionen durch T. whipplei gedacht werden. Diagnostisch wegweisend ist die Untersuchung des Gelenkpunktates auf T. whipplei mittels Polymerasekettenreaktion.

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Molecular ultrasound imaging is an attractive non-invasive technology widely available for rapid clinical diagnosis. We hypothesized that thrombolytic drugs loaded microbubbles (MBs), which are selectively targeted to activated platelets, will allow high-resolution, real-time imaging of thrombosis, and at the same time offer potent thrombolytic efficacy without bleeding complications, and enable the immediate monitoring of success or failure of thrombolysis. Our therapeutic agents/imaging particles, targeted theranostic microbubbles (TT-MB), consist of a fusion construct that combines the fibrinolytic drug urokinase, echo-enhancing microbubbles for visualization by ultrasonography, and an activated-platelet-specific single-chain antibody for targeting specifically to thrombi. In the ferric-chloride induced carotid artery thrombosis mouse model, treatment with TT-MB significantly reduced thrombus size after 45 min, while no significant difference was observed in the MB that were targeted but without urokinase (37.09 ± 5.6 vs. 97.16 ± 4.3, mean % change ± SEM, normalized to baseline thrombus size, p<0.001). The same degree of efficient thrombolysis was only achievable using a high dose of urokinase (NS). We also show that the targeting and thus clot-enrichment effect of TT-MBs results in a highly potent fibrinolysis that could only be matched using high doses of non-targeted urokinase. However, the latter is associated with a highly prolonged bleeding time (79.25 ± 6.5 vs. 1079.25 ± 260.7, seconds ± SEM, p<0.001). In contrast, TT-MB does not prolong bleeding time (NS). In conclusion, activated platelet targeted microbubbles conjugated with recombinant urokinase represent a novel and unique theranostic approach to simultaneously diagnose and treat thrombosis as well as to immediately monitor success or failure of thrombolysis. This unique technology holds promise for major progress towards rapid diagnosis and bleeding-free, potent therapy of the vast number of patients suffering from thrombotic diseases.

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S353useful in the management of trauma patients with suspected BCI.http://dx.

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