Systematic Evaluation of Pharmacokinetic Models for Model-Informed Precision Dosing of Meropenem in Critically Ill Patients Undergoing Continuous Renal Replacement Therapy

The altered pharmacokinetics of renally cleared drugs such as meropenem in critically ill patients receiving continuous renal replacement therapy (CRRT) might impact target attainment. Model-informed precision dosing (MIPD) is applied to individualize meropenem dosing. However, most population pharmacokinetic (PopPK) models developed to date have not yet been evaluated for MIPD. Eight PopPK models based on adult CRRT patients were identified in a systematic literature research and encoded in NONMEM 7.4. A data set of 73 CRRT patients from two different study centers was used to evaluate the predictive performance of the models using simulation and prediction-based diagnostics for i) a priori dosing based on patient characteristics only and ii) Bayesian dosing by including the first measured trough concentration. Median prediction error (MPE) for accuracy within |20%| (95% confidence intervals including zero) and median absolute prediction error (MAPE) for precision ≤ 30% were considered clinically acceptable. For a priori dosing, most models (n = 5) showed accuracy and precision MPE within |20%| and MAPE <35%. The integration of the first measured meropenem concentration improved the predictive performance of all models (median MAPE decreased from 35.4 to 25.0%; median MPE decreased from 21.8 to 4.6%). The best predictive performance for intermittent infusion was observed for the O’Jeanson model, including residual diuresis as covariate (a priori and Bayesian dosing MPE within |2%|, MAPE <30%). Our study revealed the O′Jeanson model as the best-predicting model for intermittent infusion. However, most of the selected PopPK models are suitable for MIPD in CRRT patients when one therapeutic drug monitoring sample is available

Relationship between Lipoprotein (a) and cognitive function – Results from the Berlin Aging Study II

It has been suggested that an age-related loss of cognitive function might be driven by atherosclerotic effects associated with altered lipid patterns. However, the relationship between Lipoprotein (a) [Lp(a)] and healthy cognitive aging has not yet been sufficiently investigated. For the current analysis we used the cross-sectional data of 1,380 Berlin Aging Study II (BASE-II) participants aged 60 years and older (52.2% women, mean age 68 ± 4 years). We employed the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD)-Plus test battery to establish latent factors representing continuous measures of domain specific cognitive functions. Regression models adjusted for APOE genotypes, lipid parameters and other risk factors for cognitive impairment were applied to assess the association between Lp(a) and performance in specific cognitive domains. Men within the lowest Lp(a)-quintile showed better cognitive performance in the cognitive domain executive functions and processing speed (p = 0.027). No significant results were observed in women. The results of the current analysis of predominantly healthy BASE-II participants point towards an association between low Lp(a) concentrations and better cognitive performance. However, evidence for this relationship resulting from the current analysis and the employment of a differentiated cognitive assessment is rather weak

High-Throughput miRNA and mRNA Sequencing of Paired Colorectal Normal, Tumor and Metastasis Tissues and Bioinformatic Modeling of miRNA-1 Therapeutic Applications

MiRNAs are discussed as diagnostic and therapeutic molecules. However, effective miRNA drug treatments with miRNAs are, so far, hampered by the complexity of the miRNA networks. To identify potential miRNA drugs in colorectal cancer, we profiled miRNA and mRNA expression in matching normal, tumor and metastasis tissues of eight patients by Illumina sequencing. We validated six miRNAs in a large tissue screen containing 16 additional tumor entities and identified miRNA-1, miRNA-129, miRNA-497 and miRNA-215 as constantly de-regulated within the majority of cancers. Of these, we investigated miRNA-1 as representative in a systems-biology simulation of cellular cancer models implemented in PyBioS and assessed the effects of depletion as well as overexpression in terms of miRNA-1 as a potential treatment option. In this system, miRNA-1 treatment reverted the disease phenotype with different effectiveness among the patients. Scoring the gene expression changes obtained through mRNA-Seq from the same patients we show that the combination of deep sequencing and systems biological modeling can help to identify patient-specific responses to miRNA treatments. We present this data as guideline for future pre-clinical assessments of new and personalized therapeutic options

Analyse regulatorischer Mechanismen und Identifizierung von microRNAs als Biomarker im kolorektalen Karzinom

Colorectal cancer (CRC) is the third most common malignant neoplasm and a major cause of cancer mortality worldwide. It is known that microRNAs play a critical role in oncogenic signaling pathways, including oncogenesis, progression, invasion, metastasis and angiogenesis. Previous studies of microRNA expression patterns in CRC elucidated a strong association between expression levels of microRNAs and the tumor stage as well as the survival prognosis for cancer patients. To investigate the microRNA expression patterns in a global scale we performed microRNA expression analyses with Illumina next generation sequencing technologies. We sequenced smallRNAs of eight colon cancer patients, each with matching normal, tumor and metastasis tissues from the same patient and analyzed in addition the microRNA expression in colon cancer cell lines SW480 and their corresponding metastasis cell line SW620. We found new and already known microRNAs, and validated different expression patterns using TaqMan assay technologies. We found that an identified signature of two microRNAs, miR-1 and miR-135b, suffice in combination to completely discriminate tumor from normal colorectal mucosa. We extended our screen to 330 additional tumor and normal tissue samples and were able to confirm these microRNAs as potential biomarkers in tumors. The most promising candidate we identified, miR-1, showed a significantly reduced expression in primary colon tumor and metastasis and was constantly down-regulated over 16 additional tumor entities. This microRNA is reported to target and inhibit c-Met (met proto-oncogene (hepatocyte growth factor receptor)) in rhabdomyosarcoma and it is also known as down-regulated in primary lung cancer tissues and cell lines. Based on these findings and on the results of our expression analyses we could demonstrate an effect of miR-1 overexpression on cell viability and on wound healing behavior in colon cancer cells. The functional analyses showed a tumor suppressive activity of miR-1 in the advancement of CRC. Using target prediction algorithms, such as TargetScan and PicTar, we identified PTPLAD1 (protein tyrosine phosphatase-like A domain containing 1) as target and showed a direct regulation through miR-1 through GFP reporter assay. Additionally, the influence on the chemosensitivity of CRC cells towards camptothecin in response to a miR-1 overexpression was investigated, and a synergistic effect was shown in colon cancer cell lines. Within further studies we used PyBioS, a systems-biology simulation of cellular cancer models, to examine miR-1 function and the effects of a miR-1 depletion as well as overexpression as a potential therapeutic option. For our colon cancer patients we showed that a combination of deep sequencing data and a systems biological modeling of microRNA drug treatment could be a promising tool to realize new strategies for personalized cancer therapy, where a patient-specific prognosis could be possible. In this study not only known microRNAs were analyzed using next generation sequencing. In addition, we were able to identify and validate not yet annotated microRNAs. Using Northern Blot analyses we proofed the existence of a novel microRNA localized on chromosome 17 (chr17:70256349-70256434) with a predicted secondary structure that underlines the integrity of this novel microRNA. As an additional characteristic for colon cancer progression we investigated mutations in microRNA regions, whereas the identified unknown variations localized in miR- 663b and miR-1324 were determined as somatic mutations. Based on the whole exome re-sequencing data we analyzed mutation rates in microsatellite instable (MSI) and stable (MSS) colon cancer patients. Applying two different re- sequencing technologies, microarray-based-genomic selection technology and a multiplex exon capturing approach, we observed a higher mutation rate in MSI colon cancer patients. In conclusion, this work emphasized the critical role of microRNAs in the pathogenesis of colorectal cancer and underlines the significance of microRNAs in the development of new strategies for individualized cancer treatment. This approach could facilitate the identification of novel diagnostic and prognostic biomarkers, but also for the design of new therapeutic molecules.Kolorektale Karzinome gehören zu den dritthäufigsten malignen Neoplasmen und zählen weltweit zu der häufigsten Todesursache. Es ist bekannt, dass microRNAs eine entscheidende Rolle in Signalwegen, wie der Onkogenese, Tumorprogression und -invasion, sowie der Metastasierung und Angiogenese spielen. Frühere Studien von microRNA-Expressionsmustern im kolorektalen Karzinom zeigten einen engen Zusammenhang zwischen den Expressionsintesitäten von microRNAs und dem Tumorstadium sowie der Überlebensprognose von Krebspatienten. Um microRNA- Expressionsmuster im globalen Maßstab zu untersuchen, führten wir microRNA- Expressionsanalysen unter Anwendung der Illumina „Next-Generation“ Sequenzierungstechnologie (NGS) durch. Wir sequenzierten die „smallRNA“ Fraktion von acht Darmkrebspatienten, dabei von jedem Patienten jeweils Normal-, Tumor- und Metastasengewebe. Zusätzlich wurde die microRNA-Expression in der Darmkrebszelllinie SW480 und ihrer entsprechenden Metastasenzelllinie SW620 von uns analysiert. Hierbei fanden wir neue als auch bereits bekannte microRNAs und validierten verschiedene Expressionsmuster unter Verwendung der „TaqMan Assay“ Technologie. Eine von uns identifizierte Expressionssignatur von zwei microRNAs, miR-1 und miR-135b, genügte, um eine vollständige Auftrennung des Tumorgewebes von der normalen kolorektalen Schleimhaut zu erreichen. Wir erweiterten unsere Untersuchungen auf 330 zusätzliche Tumor- und Normalgewebeproben und waren in der Lage, die erwähnten microRNAs als potentielle Biomarker für Tumore zu bestätigen. Der vielversprechendste von uns identifizierte Kandidat, miR-1, zeigte eine signifikant reduzierte Expression im primären Darmkarzinom und in Metastasen, ebenso war miR-1 in 16 zusätzlichen Tumorentitäten konstant herunterreguliert. Diese microRNA interagiert und inhibiert das Onkogen c-Met (met proto-oncogene (hepatocyte growth factor receptor)) im Rhabdomyosarkom, und ist ebenfalls im primären Lungenkarzinomgewebe als auch in Lungenkarzinomzelllinien herunterreguliert. Basierend auf diesen Forschungsergebnissen und anhand der von uns aus Expressionsanalysen erhaltenen Resultate, konnten wir einen Effekt auf die Zellviabilität und das Wundheilungsverhalten von miR-1-überexpremierenden Darmkarzinomzellen demonstrieren. Funktionelle Analysen zeigten eine tumorsuppressive Aktivität von miR-1 im Hinblick auf die fortschreitende Entwicklung eines kolorektalen Karzinoms. Unter Anwendung von Vorhersagealgorithmen, wie TargetScan und PicTar, identifizierten wir verschiedene miR-1 Targetgene und selektionierten PTPLAD1 (protein tyrosine phosphatase-like A domain containing 1), VEGFA (vascular endothelial growth factor A), PDGFA (platelet-derived growth factor alpha polypeptide) und HIF1A (hypoxia inducible factor 1, alpha subunit (basic helix-loop-helix transcription factor)) für weiterführende GFP-Reporterassays, in deren Verlauf wir eine direkte Regulation von PTPLAD1 durch miR-1 beweisen konnten. Darüber hinaus untersuchten wir den Einfluss auf die Chemosensitivität in kolorektalen Karzinomzellen gegenüber Champtothecin als Antwort auf eine miR-1 Überexpression und konnten einen synergistischen Effekt in Darmkrebszelllinien nachweisen. In weiterführenden Analysen verwendeten wir PyBioS, ein systembiologisches Simulationsprogramm, das auf zellulären Krebsmodellen basiert, um miR-1 als mögliche Therapieoption zu untersuchen. Für die von uns untersuchten Darmkrebspatienten konnten wir zeigen, dass eine Kombination von Sequenzierungsdaten und einer systembiologischen Modellierung der microRNA- bezogenen Arzneimitteltherapie ein vielversprechendes Hilfsmittel darstellt, um neue Strategien in der personalisierten Krebstherapie zu realisieren. Die Erstellung patientenspezifischer Prognosen könnte dadurch erreicht werden. In dieser Studie konnten nicht nur bereits bekannte microRNAs mit Hilfe der Next- Generation-Sequenzierungstechnologie analysiert, sondern auch unbekannte microRNAs identifiziert und validiert werden. Unter Anwendung von Northern Blot Analysen war es möglich, die Existenz einer neuen microRNA zu beweisen, die auf Chromosom 17 (chr17:70256349-70256434) lokalisiert ist und deren prognostizierte Sekundär-Struktur ebenfalls die Integrität der neu identifizierten microRNA unterstreicht. Als eine weitere mögliche Ursache der Darmkrebsentwicklung untersuchten wir Mutationen in microRNA-Regionen, wobei die identifizierten und noch nicht annotierten Variationen, lokalisiert in miR-663b und miR-1324, als somatische Mutationen bestimmt wurden. Im Rahmen der Mutationsanalysen konnten wir auch zeigen, dass die Mutationsrate in mikrosatelliten-instabilen (MSI) Darmtumoren im Gegensatz zu mikrosatelliten- stabilen (MSS) signifikant erhöht sind. Zusammenfassend lässt sich sagen, dass die vorliegende Arbeit die entscheidende Rolle von microRNAs in der Pathogenese des kolorektalen Karzinoms hervorhebt, und die Signifikanz von microRNAs in der Entwicklung neuer Strategien für die individualisierte Krebstherapie unterstreicht, in der microRNAs sowohl als neue diagnostische und prognostische, aber auch als potentielle neue therapeutische Wirkstoffe fungieren können

Supplement to hdl:10013/epic.31930, doi:10.1594/PANGAEA.758728

This data set provides a detailed inventory of lakes in the Lena Delta, northern Siberia, with respect to the lakes' association with one of the three geomorphological main terraces of the Lena Delta. The inventory is based on Landsat-7 ETM+ image data and spatial analysis in a Geographical Information System (GIS). Several morphometric lake attributes were determined from the resulting dataset and statistically analyzed. Significant differences in the morphometric lake characteristics allowed the distinction of a mean lake type for each main terrace. The lake types reflect the special lithological and cryolithological conditions and geomorphological processes prevailing on each terrace. In Morgenstern et al. (2008), special focus was laid on the investigation of lake orientation and the discussion of possible mechanisms for the evolution of the second terrace's oriented lakes

Validation and Application of an HPLC-UV Method for Routine Therapeutic Drug Monitoring of Cefiderocol

Cefiderocol is a new siderophore cephalosporin approved for the treatment of multidrug resistant bacteria including activity against carbapenem-resistant Enterobacterales and Pseudomonas aeruginosa. As cephalosporins are known for their high pharmacokinetic variability in critically ill patients, cefiderocol therapeutic drug monitoring might become a valuable tool. Therefore, we aimed to develop and validate a simple, rapid, cost-effective high performance liquid chromatography (HPLC) method for the quantification of cefiderocol in serum. Samples were treated for protein precipitation followed by chromatographic separation on a reverse phase column (HPLC C-18) with gradient elution of the mobile phase. Cefiderocol was detected via UV absorption and quantification was performed with the internal standard (metronidazole) method. The calibration range showed linearity from 4 to 160 mg/L. The intra and interday precision was less than 10% with a recovery rate of 81%. The method was successfully used for the analysis of subsequent serum samples of critically ill patients and showed good performance in monitoring serum levels and optimizing antibiotic therapy

Cefiderocol in Critically Ill Patients with Multi-Drug Resistant Pathogens: Real-Life Data on Pharmacokinetics and Microbiological Surveillance

Cefiderocol is a new siderophore-cephalosporin for the treatment of multi-drug resistant Gram-negative pathogens. As a reserve agent, it will and should be used primarily in critically ill patients in the upcoming years. Due to the novelty of the substance little data on the pharmacokinetics in critically ill patients with septic shock and renal failure (including continuous renal replacement therapy and cytokine adsorber therapy) is available. We performed therapeutic drug monitoring in a cohort of five patients treated with cefiderocol, to improve the knowledge on pharmacokinetics in this vulnerable patient population. As expected for a cephalosporin with predominantly renal elimination the maintenance dose could be reduced in patients with renal impairment or on continuous renal replacement therapy. The manufacturer’s dosing instructions were sufficient to achieve a drug level well above the MIC. However, the addition of a cytokine adsorber might reduce serum levels substantially, so that in this context therapeutic drug monitoring and dose adjustment are recommended

In vitro removal of anti-infective agents by a novel cytokine adsorbent system

The aim of this study is to describe the in vitro adsorption of anti-infective drugs onto an extracorporeal cytokine adsorber.Various anti-infective drugs (β-lactams, quinolones, aminoglycosides, glycopeptides, azole antimycotics) were prepared in normal saline 0.9% and human albumin 5%, and pumped through a cytokine cartridge (CytoSorb; CytoSorbents Corporation, Monmouth Junction, NJ, USA) at a flow rate of 1.2 L/h for 1.5 h. In addition, meropenem and ciprofloxacin were dissolved in reconstituted blood and run through a CytoSorb cartridge, which was integrated into a continuous renal replacement therapy circuit with a flow rate of 2 L/h for 18 h. Samples from the solution, pre- and post-filter, were quantified by high-performance liquid chromatography with ultraviolet detection and fluorescence polarisation immunoassay.Observed mean clearance of the drugs in normal saline was 1.22 ± 0.07 L/h. In human albumin, clearance was 1.29 ± 0.08 L/h. In reconstituted blood, clearance of meropenem decreased from 5.4 to 1.4 L/h and for ciprofloxacin from 6.3 to 4.3 L/h within the first 1.5 h because of early drug adsorption. Continuous renal replacement therapy clearance measured without CytoSorb was stable at 2 and 1.7 L/h, respectively. Approximately 400 mg of meropenem and 300 mg of ciprofloxacin had been adsorbed by CytoSorb, suggesting that these amounts are the maximum adsorptive capacity for these drugs.In these settings, all tested drugs were adsorbed by the cartridge in relevant amounts. The identified maximum adsorptive capacity and the rapid decline in concentration during the first 1.5 h of CytoSorb use suggest that the administration of an additional dose within the first hours of CytoSorb treatment may be reasonable. In addition, early therapeutic drug monitoring should be considered

TLR2 has a detrimental role in mouse transient focal cerebral ischemia

A significant up-regulation of Toll-like-receptor (TLR) mRNAs between 3 and 48 h reperfusion time after induction of transient focal cerebral ischemia for 1 h was revealed by applying global gene expression profiling in postischemic mouse brains. Compared to TLR4 and TLR9, TLR2 proved to be the most significantly up-regulated TLR in the ipsilateral brain hemisphere. TLR2-protein was found to be expressed mainly in microglia in the postischemic brain tissue, but also in selected endothelial cells, neurons, and astrocytes. Additionally, TLR2-related genes with pro-inflammatory and pro-apoptotic capabilities were induced. Therefore we hypothesized that TLR2-signaling could exacerbate the primary brain damage after ischemia. Two days after induction of transient focal cerebral ischemia (1 h), we found a significant decrease of the infarct volume in TLR2 deficient mice compared to wild type mice (75 ± 5 vs. 42 ± 7 mm3). We conclude that TLR2 up-regulation and TLR2-signaling are important events in focal cerebral ischemia and contribute to the deterioration of ischemic damage

The association of the 5-HTTLPR polymorphism and the response to different stressors in healthy males

The experience of stress is related to individual wellbeing and vulnerability to psychopathology. Therefore, understanding the determinants of individual differences in stress reactivity is of great concern from a clinical perspective. The functional promotor polymorphism of the serotonin transporter gene (5-HTTLPR/rs25531) is such a factor, which has been linked to the acute stress response as well as the adverse effect of life stressors. In the present study, we compared the impact of two different stress induction protocols (Maastricht Acute Stress Test and ScanSTRESS) and the respective control conditions on affective ratings, salivary cortisol levels and cognitive performance. To this end, 156 healthy young males were tested and genotyped for the 5-HTTLPR/rs25531 polymorphism. While combined physiological and psychological stress in the MAST led to a greater cortisol increase compared to control conditions as well as the psychosocial ScanSTRESS, subjective stress ratings were highest in the ScanSTRESS condition. Stress induction in general affected working memory capacity but not response inhibition. Subjective stress was also influenced by 5-HTTLPR/rs25531 genotype with the high expression group showing lower stress ratings than lower expression groups. In line with previous research, we identified the low expression variant of the serotonin transporter gene as a risk factor for increased stress reactivity. While some dimensions of the human stress response may be stressor specific, cognitive outcomes such as working memory performance are influenced by stress in general. Different pathways of stress processing and possible underlying mechanisms are discussed