Improved kinetics of rIX-FP, a recombinant fusion protein linking factor IX with albumin, in cynomolgus monkeys and hemophilia B dogs: Improved kinetics of rIX-FP

Prophylaxis of hemophilia B, at present, requires multiple infusions of human factor IX (FIX) concentrates per week. A FIX molecule with a prolonged half-life has the potential to greatly improve convenience of, and adherence to, prophylaxis

A randomized, controlled, prospective trial to evaluate the haemostatic effect of Lyostypt versus Surgicel in arterial bypass anastomosis: "COBBANA" trial

<p>Abstract</p> <p>Background</p> <p>The development of suture hole bleeding at peripheral arterial bypass anastomoses using PTFE graft prostheses is a common problem in peripheral vascular surgery. Traditionally the problem is managed by compression with surgical swabs and reversal heparin or by using several haemostatic device (e.g. different forms of collagen, oxidized cellulose, gelatine sponge, ethylcyanoacrylate glue or fibrin) with various success. Preclinical data suggest that the haemostatic effect of collagen is stronger than that of oxidized cellulose, but no direct clinical comparison of their hemostatic performance has been published so far.</p> <p>Design</p> <p>This randomized, controlled, prospective trial evaluates the haemostatic effect of Lyostypt versus Surgicel in arterial bypass anastomosis. 28 patients undergoing an elective peripheral vascular reconstruction due to peripheral vascular disease will be included. Suture hole bleeding occurring at the arterial bypass anastomosis using a PTFE prostheses will be stopped by the application of Lyostypt and/or Surgicel. The proximal anastomoses will be randomized intraoperatively. The patients will be allocated into 4 different treatment groups. Group1 Lyostypt distal/Surgicel proximal; Group 2: Lyostypt proximal/Surgicel distal; Group 3: Surgicel distal and proximal; Group 4: Lyostypt distal and proximal. Primary endpoint of the study is time to haemostasis. Secondary endpoints are the number of intraoperatively used haemostatic devices, postoperative mortality within 30 days as well as the intraoperative efficacy rating of the two devices evaluated by the surgeon. As a safety secondary parameter, the local and general complication occurring till 30 ± 10 days postoperatively will also be analysed. After hospital discharge the investigator will examine the enrolled patients again at 30 days after surgery.</p> <p>Discussion</p> <p>The COBBANA trial aims to assess, whether the haemostatic effect of Lyostypt is superior to Surgicel in suture hole bleedings of arterial bypass anastomoses.</p> <p>Trial registration</p> <p>NCT00837954</p

Prolastin, a pharmaceutical preparation of purified human α1-antitrypsin, blocks endotoxin-mediated cytokine release

BACKGROUND: α1-antitrypsin (AAT) serves primarily as an inhibitor of the elastin degrading proteases, neutrophil elastase and proteinase 3. There is ample clinical evidence that inherited severe AAT deficiency predisposes to chronic obstructive pulmonary disease. Augmentation therapy for AAT deficiency has been available for many years, but to date no sufficient data exist to demonstrate its efficacy. There is increasing evidence that AAT is able to exert effects other than protease inhibition. We investigated whether Prolastin, a preparation of purified pooled human AAT used for augmentation therapy, exhibits anti-bacterial effects. METHODS: Human monocytes and neutrophils were isolated from buffy coats or whole peripheral blood by the Ficoll-Hypaque procedure. Cells were stimulated with lipopolysaccharide (LPS) or zymosan, either alone or in combination with Prolastin, native AAT or polymerised AAT for 18 h, and analysed to determine the release of TNFα, IL-1β and IL-8. At 2-week intervals, seven subjects were submitted to a nasal challenge with sterile saline, LPS (25 μg) and LPS-Prolastin combination. The concentration of IL-8 was analysed in nasal lavages performed before, and 2, 6 and 24 h after the challenge. RESULTS: In vitro, Prolastin showed a concentration-dependent (0.5 to 16 mg/ml) inhibition of endotoxin-stimulated TNFα and IL-1β release from monocytes and IL-8 release from neutrophils. At 8 and 16 mg/ml the inhibitory effects of Prolastin appeared to be maximal for neutrophil IL-8 release (5.3-fold, p < 0.001 compared to zymosan treated cells) and monocyte TNFα and IL-1β release (10.7- and 7.3-fold, p < 0.001, respectively, compared to LPS treated cells). Furthermore, Prolastin (2.5 mg per nostril) significantly inhibited nasal IL-8 release in response to pure LPS challenge. CONCLUSION: Our data demonstrate for the first time that Prolastin inhibits bacterial endotoxin-induced pro-inflammatory responses in vitro and in vivo, and provide scientific bases to explore new Prolastin-based therapies for individuals with inherited AAT deficiency, but also for other clinical conditions

Listeria pathogenesis and molecular virulence determinants

The gram-positive bacterium Listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. Pregnant women, neonates, the elderly, and debilitated or immunocompromised patients in general are predominantly affected, although the disease can also develop in normal individuals. Clinical manifestations of invasive listeriosis are usually severe and include abortion, sepsis, and meningoencephalitis. Listeriosis can also manifest as a febrile gastroenteritis syndrome. In addition to humans, L. monocytogenes affects many vertebrate species, including birds. Listeria ivanovii, a second pathogenic species of the genus, is specific for ruminants. Our current view of the pathophysiology of listeriosis derives largely from studies with the mouse infection model. Pathogenic listeriae enter the host primarily through the intestine. The liver is thought to be their first target organ after intestinal translocation. In the liver, listeriae actively multiply until the infection is controlled by a cell-mediated immune response. This initial, subclinical step of listeriosis is thought to be common due to the frequent presence of pathogenic L. monocytogenes in food. In normal indivuals, the continual exposure to listerial antigens probably contributes to the maintenance of anti-Listeria memory T cells. However, in debilitated and immunocompromised patients, the unrestricted proliferation of listeriae in the liver may result in prolonged low-level bacteremia, leading to invasion of the preferred secondary target organs (the brain and the gravid uterus) and to overt clinical disease. L. monocytogenes and L. ivanovii are facultative intracellular parasites able to survive in macrophages and to invade a variety of normally nonphagocytic cells, such as epithelial cells, hepatocytes, and endothelial cells. In all these cell types, pathogenic listeriae go through an intracellular life cycle involving early escape from the phagocytic vacuole, rapid intracytoplasmic multiplication, bacterially induced actin-based motility, and direct spread to neighboring cells, in which they reinitiate the cycle. In this way, listeriae disseminate in host tissues sheltered from the humoral arm of the immune system. Over the last 15 years, a number of virulence factors involved in key steps of this intracellular life cycle have been identified. This review describes in detail the molecular determinants of Listeria virulence and their mechanism of action and summarizes the current knowledge on the pathophysiology of listeriosis and the cell biology and host cell responses to Listeria infection. This article provides an updated perspective of the development of our understanding of Listeria pathogenesis from the first molecular genetic analyses of virulence mechanisms reported in 1985 until the start of the genomic era of Listeria research

Untersuchungen zur pharmakologischen Charakterisierung von Gerinnungsfaktor XIIa-Inhibitoren

Unter physiologischen Bedingungen limitiert die Hämostase nach einer Gefäßverletzung den Blutverlust. Dagegen fördern eine Plättchen-Aktivierung und die Blutgerinnung unter pathologischen Bedingungen die Entstehung einer Thrombose. Hierbei bewirkt der Kontakt zwischen Blut und Fremdoberflächen die Einleitung des intrinsischen Gerinnungsweges über eine FXII-Aktivierung. Dies ist beispielsweise eine Komplikation bei der Anwendung einer extrakorporalen Membranoxygenierung (ECMO). Folglich benötigen Patienten eine stabile antikoagulative Medikation, die jedoch mit einem erhöhten Blutungsrisiko einhergeht. Aus aktuellen Studien in verschiedenen Thrombosemodellen in Nagern und Primaten ging hervor, dass eine Defizienz oder Hemmung von FXII(a) eine verlässliche antithrombotische Wirksamkeit bietet. Beachtenswert war dabei die uneingeschränkte hämostatische Kapazität in den behandelten Tieren. Daher war die erste Fragestellung der vorliegenden Arbeit die antithrombotische Wirksamkeit von zwei spezifischen FXIIa-Inhibitoren zu untersuchen. Diese waren ein voll humaner, gegen FXIIa gerichteter monoklonaler Antikörper (anti-FXIIa MAb 3F7) und das rekombinante Protein rHA-Infestin-4, welches aus einer Raubwanze stammt. Beide Substanzen zeigten in verschiedenen Thrombosemodellen einen stabilen antithrombotischen Effekt, z. B. bei dem Fremdoberflächen-induzierten Thrombosemodells des arteriovenösen Shunt-Modells in den Spezies Maus und Kaninchen. Der zweite Schwerpunkt der vorliegenden Arbeit war zu untersuchen, inwiefern eine FXIIa-Hemmung im murinen Schlaganfallmodell zu einer Neuroprotektion beiträgt. Aus aktuellen Studien im Schlaganfallmodell ist bekannt, dass FXII-defiziente Mäuse und prophylaktisch mit rHA-Infestin-4 behandelte reduzierte klinische Defizite und ein reduzierte Infarktvolumen aufwiesen. Dies ist vermutlich auf verringerte Reperfusionsschäden zurück zu führen. Daher wurde für die vorliegende Arbeit die prophylaktische Applikation von anti-FXIIa MAb 3F7 im gleichen Modell untersucht. In einer zusätzlichen Studie wurde rHA-Infestin-4 therapeutisch verabreicht. Der beste neuroprotektive Effekt zeigte sich in der prophylaktischen Substanz-Applikation, denn hier wurde eine Reduzierung von Inflammation, Mikrothrombose und Mortalität beobachtet, ohne eine erhöhte Blutungsneigung hervorzurufen. Die Resultate dieser Arbeit deuten also darauf hin, dass eine FXIIa-Inhibition bei Thrombosen unterschiedlicher Entstehungsarten einen verlässlichen antithrombotischen Schutz bietet, ohne die physiologische Hämostase zu beeinträchtigen. Weiterhin konnte die prophylaktische Behandlung mit FXIIa- Inhibitoren die klinischen Defizite im murinen Schlaganfallmodell signifikant verbessern