Strukturanalyse der spezifischen Inaktivierung des Toll-ähnlichen Rezeptors 2

Toll-like receptors (TLRs) are critical receptors for pathogen detection following microbial infections. In addition, they participate in responding to a variety of tissue damage-derived endogenous molecules. In both processes, binding of a ligand induces the dimerization of two TLRs and stimulates cellular immune responses. Occasionally, however, the activation of TLRs can also result in chronic inflammation diseases. This happens in situations where control over the release of pro-inflammatory cytokines is lost. Possible treatments include the usage of antagonistic drugs that inhibit the TLR-based immune response. The monoclonal antibody OPN-305, an efficient inhibitor of TLR2, has successfully been used to treat septic shock and rheumatoid arthritis in mice and ischemia/reperfusion injury in humans. However, whereas the efficacy of the antibody was well established, its molecular mechanism remained unexplained. In this thesis, the complex between the extracellular domain of murine TLR2 and the fragment antigen-binding domain of OPN-305 was generated and purified. A first structural description of this complex was achieved by negative stain electron microscopy (EM) at a resolution of ~22 Å. The three-dimensional reconstruction reveals that the antibody binds laterally within the TLR1/TLR6 dimerization interface. The results indicate that the leucine rich repeats 11 to 14 are involved in the protein-protein interaction allowing ten amino acids on the surface of TLR2 to be identified as constituting the probable, highly discontinuous epitope. These results immediately suggest the mechanism of TLR2 inhibition and the antagonistic property of OPN-305 to derive from its ability to block the heterodimerization of TLR2 resulting in silencing of downstream signaling cascades.Die Toll-ähnlichen Rezeptoren (TLRs) sind entscheidende Rezeptoren bei der Erregererkennung nach mikrobiellen Infektionen. Darüber hinaus sind sie in der Reaktion auf eine Vielzahl durch Gewebeschäden freigesetzter endogener Moleküle beteiligt. In beiden Prozessen induziert die Bindung eines Liganden die Dimerisierung zweier TLRs und stimuliert zelluläre Immunantworten. Gelegentlich kann jedoch eine Überaktivierung von TLRs chronische Entzündungen hervorrufen. Dies geschieht in Situationen, in denen die Kontrolle über die Freisetzung pro-inflammatorischer Zytokine verloren geht. Eine mögliche Behandlung ist der Einsatz antagonistischer Medikamente, die die TLR-induzierte Immunantwort hemmen. Der monoklonale Antikörper OPN-305, ein effizienter Inhibitor von humanem TLR2, wurde erfolgreich zur Behandlung von septischem Schock und rheumatoider Arthritis bei Mäusen sowie Ischämie-Reperfusionsschäden beim Menschen getestet. Während jedoch die Wirksamkeit des Antikörpers etabliert ist, blieb der molekulare Mechanismus ungeklärt. In dieser Arbeit wurde der Komplex zwischen der extrazellulären Domäne von TLR2 und des Antigen-bindenden Fragments von OPN-305 erzeugt und gereinigt. Eine erste strukturelle Beschreibung dieses Komplexes gelang durch Negativfärbung-Elektronenmikroskopie bei einer Auflösung von 22 Å. Die dreidimensionale Rekonstruktion des Komplexes zeigt eine Bindung des Antikörpers an TLR2 lateral im Bereich der TLR1/TLR6 Dimerisierungsfläche. Dabei sind die Leucin-reichen Wiederholungen 11 bis 14 an der Protein-Protein-Wechselwirkung beteiligt. Zehn Aminosäuren auf der Oberfläche von TLR2 konnten als wahrscheinlicher Bestandteil des stark diskontinuierlichen Epitops identifiziert werden. Die Ergebnisse deuten darauf hin, dass der Mechanismus der TLR2-Inhibierung und die antagonistische Eigenschaft des OPN-305 auf dessen Fähigkeit beruht, die Heterodimerisierung von TLR2 zu blockieren und so nachgeschaltete Signalkaskaden auszuschalten

Outcome after intracranial hemorrhage under dabigatran and reversal with idarucizumab versus under vitamin-K-antagonists – the RIC-ICH study

BackgroundIntracranial hemorrhage (ICH) is a rare but serious side effect associated with the use of oral anticoagulants, such as dabigatran. The specific reversal agent for dabigatran, idarucizumab, is available for the management of individuals with ICH. The aim of this study was to provide real-world evidence on patients with ICH and effective treatment with dabigatran and reversal with idarucizumab in clinical routine compared to those under effective treatment with vitamin-K-antagonist (VKA).MethodsRegistration of Idarucizumab for Patients with IntraCranial Hemorrhage (RIC-ICH) is a non-interventional study conducted in 22 German stroke units that prospectively enrolled dabigatran patients treated with idarucizumab. Retrospective data from VKA patients served as reference population. Main objective was in-hospital mortality. Further objectives included change in bleeding volume, stroke severity, and functional status.ResultIn-hospital mortality was 26.7% in 15 dabigatran and 27.3% in 88 VKA patients (hazard ratio 1.00, 95% CI 0.29–2.60). In patients with bleeding volume > 60 ml, mortality was lower in the dabigatran group (N = 6, 33%) compared to the VKA group (N = 15, 67%; HR 0.24, 95% CI 0.04–0.96). No differences were observed in secondary endpoints between dabigatran and VKA patients.ConclusionThese results, based on data from routine clinical practice, suggest that in-hospital mortality after idarucizumab treatment is comparable to that in patients pretreated with VKA. Due to the low precision of estimates, the results must be interpreted with caution

Lenalidomide in combination with dexamethasone at first relapse in comparison with its use as later salvage therapy in relapsed or refractory multiple myeloma

This subset analysis of data from two phase III studies in patients with relapsed or refractory multiple myeloma (MM) evaluated the benefit of initiating lenalidomide plus dexamethasone at first relapse. Multivariate analysis showed that fewer prior therapies, along with β2-microglobulin (≤2.5 mg/L), predicted a better time to progression (TTP; study end-point) with lenalidomide plus dexamethasone treatment. Patients with one prior therapy showed a significant improvement in benefit after first relapse compared with those who received two or more therapies. Patients with one prior therapy had significantly prolonged median TTP (17.1 vs. 10.6 months; P=0.026) and progression-free survival (14.1 vs. 9.5 months, P=0.047) compared with patients treated in later lines. Overall response rates were higher (66.9% vs. 56.8%, P=0.06), and the complete response plus very good partial response rate was significantly higher in first relapse (39.8% vs. 27.7%, P=0.025). Importantly, overall survival was significantly prolonged for patients treated with lenalidomide plus dexamethasone with one prior therapy, compared with patients treated later in salvage (median of 42.0 vs. 35.8 months, P=0.041), with no differences in toxicity, dose reductions, or discontinuations despite longer treatment. Therefore, lenalidomide plus dexamethasone is both effective and tolerable for second-line MM therapy and the data suggest that the greatest benefit occurs with earlier use

Adverse drug events in German hospital routine data: A validation of International Classification of Diseases, 10th revision (ICD-10) diagnostic codes

<div><p>Objective</p><p>Adverse drug events (ADEs) during hospital stays are a significant problem of healthcare systems. Established monitoring systems lack completeness or are cost intensive. Routinely assigned International Statistical Classification of Diseases and Related Health Problems (ICD) codes could complement existing systems for ADE identification. To analyze the potential of using routine data for ADE detection, the validity of a set of ICD codes was determined focusing on hospital-acquired events.</p><p>Material and methods</p><p>The study utilized routine data from four German hospitals covering the years 2014 and 2015. A set of ICD, 10^th Revision, German Modification (ICD-10-GM) diagnoses coded most frequently in the routine data and identified as codes indicating ADEs was analyzed. Data from psychiatric and psychotherapeutic departments were excluded. Retrospective chart review was performed to calculate positive predictive values (PPV) and sensitivity.</p><p>Results</p><p>Of 807 reviewed ADE codes, 91.2% (95%-confidence interval: 89.0, 93.1) were identified as disease in the medical records and 65.1% (61.7, 68.3) were confirmed as ADE. For code groups being predominantly hospital-acquired, 78.5% (73.7, 82.9) were confirmed as ADE, ranging from 68.5% to 94.4% dependent on the ICD code. However, sensitivity of inpatient ADEs was relatively low. 49.7% (45.2, 54.2) of 495 identified hospital-acquired ADEs were coded as disease in the routine data, from which a subgroup of 12.1% (9.4, 15.3) was coded as drug-associated disease.</p><p>Conclusions</p><p>ICD codes from routine data can provide an important contribution to the development and improvement of ADE monitoring systems. Documentation quality is crucial to further increase the PPV, and actions against under-reporting of ADEs in routine data need to be taken.</p></div

Overall positive predictive value of ICD-10-GM by proportion of hospital-acquired events.

<p>Overall positive predictive value of ICD-10-GM by proportion of hospital-acquired events.</p

Positive predictive value of ICD-10-GM by code group, and number of inpatient events.

<p>Positive predictive value of ICD-10-GM by code group, and number of inpatient events.</p

Controlled oxygenated rewarming as novel end‐ischemic therapy for cold stored liver grafts. A randomized controlled trial

Abstract Abrupt return to normothermia has been shown a genuine factor contributing to graft dysfunction after transplantation. This study tested the concept to mitigate reperfusion injury of liver grafts by gentle warming‐up using ex vivo machine perfusion prior to reperfusion. In a single center randomized controlled study, livers were assigned to conventional static cold storage (SCS) alone or to SCS followed by 90 min of ex vivo machine perfusion including controlled oxygenated rewarming (COR) by gentle and protracted elevation of the perfusate temperature from 10°C to 20°C. Primary outcome mean peak aspartate aminotransferase (AST) was 1371 U/L (SD 2871) after SCS versus 767 U/L (SD 1157) after COR (p = 0.273). Liver function test (LiMAx) on postoperative day 1 yielded 187 μg/kg/h (SD 121) after SCS, but rose to 294 μg/kg/h (SD 106) after COR (p = 0.006). Likewise, hepatic synthesis of coagulation factor V was significantly accelerated in the COR group immediately after transplantation (103% [SD 34] vs. 66% [SD 26]; p = 0.001). Fewer severe complications (Clavien‐Dindo grade ≥3b) were reported in the COR group (8) than in the SCS group (15). Rewarming/reperfusion injury of liver grafts can be safely and effectively mitigated by controlling of the rewarming kinetics prior to blood reperfusion using end‐ischemic ex vivo machine perfusion after cold storage