The Complementary Effects of Dabigatran Etexilate and Exercise Training on the Development and Stability of the Atherosclerotic Lesions in Diabetic ApoE Knockout Mice

Aim: To determine the complementary effects of dabigatran etexilate (DE), exercise training (ET), and combination (DE + ET) on the development and stability of the atherosclerotic lesions in diabetic apoE knockout (apoE-/-) mice. Methods: In 48 male apoE-/- diabetic mice, streptozotocin (STZ) was induced for 5 consecutive days. Mice received a high-fat diet (HFD) for 8 weeks and then were randomized into four groups (1. Control/CG, 2. DEG: HFD with DE, 3. ETG: ET on treadmill, 4. DE + ETG: combination DE and ET treatment). At the end of the eighth week, all mice were euthanatized and morphometry of the aortic lesions at the level of aortic valve was obtained. Collagen, elastin, MCP-1, TNF-a, matrix metalloproteinases (MMP-2,-3,-9), and TIMP-1 concentrations within plaques at the aortic valve were determined. Results: All active groups had significantly smaller aorta stenosis (DEG:7.9 ± 2.2%, ETG:17.3 ± 5.3%, DE + ETG:7.1 ± 2.7%) compared to CG (23.3 ± 5.5% p < 0.05), reduced the relative intra-plaque content of MCP-1, macrophages, MMP-3, and MMP-9, and considerably increased collagen, elastin, and TIMP-1 (p < 0.05). Group 4 showed the most pronounced results (p < 0.05). Both DEG and DE + ETG significantly reduced MMP-2 and TNF-a concentrations compared to ETG and CG (p < 0.010). Conclusion: DE and ET treatment of diabetic apoE-/- mice resulted in complementary amelioration of atherosclerotic lesions development and stability, mediated by the anti-inflammatory modulation of both DE and ET.

Sources of performance variability in deep learning-based polyp detection

PURPOSE

Validation metrics are a key prerequisite for the reliable tracking of scientific progress and for deciding on the potential clinical translation of methods. While recent initiatives aim to develop comprehensive theoretical frameworks for understanding metric-related pitfalls in image analysis problems, there is a lack of experimental evidence on the concrete effects of common and rare pitfalls on specific applications. We address this gap in the literature in the context of colon cancer screening.

METHODS

Our contribution is twofold. Firstly, we present the winning solution of the Endoscopy Computer Vision Challenge on colon cancer detection, conducted in conjunction with the IEEE International Symposium on Biomedical Imaging 2022. Secondly, we demonstrate the sensitivity of commonly used metrics to a range of hyperparameters as well as the consequences of poor metric choices.

RESULTS

Based on comprehensive validation studies performed with patient data from six clinical centers, we found all commonly applied object detection metrics to be subject to high inter-center variability. Furthermore, our results clearly demonstrate that the adaptation of standard hyperparameters used in the computer vision community does not generally lead to the clinically most plausible results. Finally, we present localization criteria that correspond well to clinical relevance.

CONCLUSION

We conclude from our study that (1) performance results in polyp detection are highly sensitive to various design choices, (2) common metric configurations do not reflect the clinical need and rely on suboptimal hyperparameters and (3) comparison of performance across datasets can be largely misleading. Our work could be a first step towards reconsidering common validation strategies in deep learning-based colonoscopy and beyond.

Abstract 3322: Diagnosis and monitoring of pediatric cancer patients using low-pass whole genome and targeted sequencing of cell-free DNA

Cell-free DNA (cfDNA) assays are transforming cancer care by enabling minimally invasive diagnosis, minimal residual disease (MRD) monitoring and by guiding risk stratification and therapy. However, progress in pediatric cancers is limited due to a) limited amounts of cfDNA b) differences in the cancer driver landscape - higher prevalence of copy number alterations (CNA) and fusions with few point mutations and c) small sample sizes.

Here, we addressed some of these challenges by performing low-pass whole genome (LPWGS) and/or targeted sequencing (TS) of cfDNA on a cohort of 125 pediatric solid (n=78) and brain (n=47) tumor patients enrolled either at diagnosis, after therapy or relapse. Plasma was collected from patients with sarcoma, renal, hepatic and germ-cell tumors; cerebrospinal fluid (CSF) during surgery from children with low and high grade gliomas, ependymomas, craniopharyngiomas and embryonal tumors; and aqueous humor for retinoblastoma. WGS libraries were constructed with the xGen Prism DNA Library Kit using 5ng of input cfDNA and sequenced (Illumina NextSeq 500) to a mean coverage of 4.1x. CNAs were evaluated using ichorCNA and compared with clinical microarray results from primary tumors. Selected cases with previously clinically reported BRAF, EWSR1 and FOXO1 canonical gene fusions and driver mutations from our OncoKids assay were analyzed using TS (Twist Bioscience) sequenced to a mean coverage of 582x.

In treatment naive cases that had an aberration detected in the primary tumor, we observed an overall positivity rate in 67% (72/107) of cases using cfDNA. For a subset of 45 cases with at least 10% circulating-tumor (ct) DNA, we compared LPWGS results with microarray data from the primary tumor and identified 88/92 (96%) of the clinically reported events suggesting its utility as a diagnostic tool. In adult cancers, proportion of short (&lt;150bp) to long fragments (S/L ratio) using LPWGS was shown to correlate with ctDNA concentration and consequently detectability. Therefore, we categorized tumor types as low-burden if the median S/L ratio was below the median value across all tumor types and as high-burden otherwise. Interestingly, ctDNA detectability rates were significantly higher in high-burden tumors (27/52 vs 28/37, Fisher’s exact P-value = 0.03) suggesting that S/L ratios could define ctDNA detectability. Though anecdotal in evidence, LPWGS demonstrated CNAs distinctly present in primary and metastatic lesions and in at least one case, revealed ctDNA in plasma, 9 months prior to relapse. These findings suggest cfDNA may be more representative of tumor clonal composition and utilized for MRD detection.

These findings affirm the clinical utility of liquid biopsy assays to diagnose and monitor a variety of pediatric solid and brain tumors. Clinical trials and larger cohorts are necessary for ctDNA guided risk and therapeutic stratification of pediatric cancers.

Citation Format: Venkata Yellapantula, Eirini Christodoulou, Katrina O’Hollaran, Jianling Ji, Liya Xu, Jesse L. Berry, Anya Zdanowicz, Leo Mascarenhas, James Amatruda, Dejerianne Ostrow, Nicholas Chapman, Jason Chu, Mark Krieger, Peter Chiarelli, Pan Yachen, Moiz Bootwalla, Xiaowu Gai, Fariba Navid, Jaclyn A. Biegel. Diagnosis and monitoring of pediatric cancer patients using low-pass whole genome and targeted sequencing of cell-free DNA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3322.

Low-pass whole-genome and targeted sequencing of cell-free DNA from cerebrospinal fluid in pediatric patients with central nervous system tumors

Background

Central nervous system tumors are the most common pediatric solid tumors and the most frequent cause of cancer-related morbidity in childhood. Significant advances in understanding the molecular features of these tumors have facilitated the development of liquid biopsy assays that may aid in diagnosis and monitoring response to therapy. In this report, we describe our comprehensive liquid biopsy platform for detection of genome-wide copy number aberrations, sequence variants, and gene fusions using cerebrospinal fluid (CSF) from pediatric patients with brain, spinal cord, and peripheral nervous system tumors.

Methods

Cell-free DNA was isolated from the CSF from 55 patients, including 47 patients with tumors and 8 controls.

Results

Abnormalities in cell-free DNA were detected in 24 (51%) patients including 11 with copy number alterations, 9 with sequence variants, and 7 with KIAA1549::BRAF fusions. Positive findings were obtained in patients spanning histologic subtypes, tumor grades, and anatomic locations.

Conclusions

This study demonstrates the feasibility of employing this platform in routine clinical care in upfront diagnostic and monitoring settings. Future studies are required to determine the utility of this approach for assessing response to therapy and long-term surveillance.

Development and Pharmacokinetics of a Novel Acetylsalicylic Acid Dry Powder for Pulmonary Administration

Aspirin is an historic blockbuster product, and it has been proposed in a wide range of formulas. Due to exacerbation risks, the pulmonary route has been seldom considered as an alternative to conventional treatments. Only recently, owing to overt advantages, inhalable acetylsalicylic acid dry powders (ASA DPI) began to be considered as an option. In this work, we developed a novel highly performing inhalable ASA DPI using a nano spray-drying technique and leucine as an excipient and evaluated its pharmacokinetics compared with oral administration. The formulation obtained showed remarkable respirability and quality features. Serum and lung ASA DPI profiles showed faster presentation in blood and higher retention compared with oral administration. The dry powder was superior to the DPI suspension. The relative bioavailability in serum and lungs claimed superiority of ASA DPI over oral administration, notwithstanding a fourfold lower pulmonary dose. The obtained ASA DPI formulation shows promising features for the treatment of inflammatory and infectious lung pathologies.

Microenvironmental changes co-occur with mosaic somatic clonal expansions in normal skin and esophagus tissues

The presence of somatic mutations, previously identified in cancers, are being increasingly recognized in normal tissues. While the role of microenvironment (ME) in tumor progression is well understood, the changes that occur in the microenvironment of normal tissues that harbor somatic mutations has not been systematically studied. Here, using normal RNA-Seq data accrued from 6544 samples across 27 tissue types from Genotype-Tissue Expression (GTEx) project, we studied the association of microenvironmental changes in the presence of somatic clonal expansions of previously implicated cancer genes. We focused our analysis on skin and esophagus since they have the highest number of samples and mutation burden together. We observed changes in microenvironmental cell-types previously implicated in tumor progression including endothelial cells, epithelial cells, pericytes, fibroblasts, chondrocytes, among others. The Epithelial-Mesenchymal-Transition (EMT) pathway is dysregulated in both skin and esophagus, along with increased hypoxia scores in samples with clonal expansions. These results suggest that microenvironmental changes play an important role in clonal expansions and potentially the initiating stages of cancer progression. Studying these changes may provide new avenues for early intervention of cancer, for targeted therapies, or enhance activities of conventional therapies.

Pharmacokinetic Characteristics of Nebulized Colistimethate Sodium Using Two Different Types of Nebulizers in Critically Ill Patients with Ventilator-Associated Respiratory Infections

Background: Rising antimicrobial resistance has led to a revived interest in inhaled colistin treatment in the critically ill patient with ventilator-associated respiratory infection (VARI). Nebulization via vibrating mesh nebulizers (VMNs) is considered the current standard-of-care, yet the use of generic jet nebulizers (JNs) is more widespread. Few data exist on the intrapulmonary pharmacokinetics of colistin when administered through VMNs, while there is a complete paucity regarding the use of JNs. Methods: In this study, 18 VARI patients who received 2 million international units of inhaled colistimethate sodium (CMS) through a VMN were pharmacokinetically compared with six VARI patients who received the same drug dose through a JN, in the absence of systemic CMS administration. Results: Surprisingly, VMN and JN led to comparable formed colistin exposures in the epithelial lining fluid (ELF) (median (IQR) AUC0-24: 86.2 (46.0-185.9) mg/L∙h with VMN and 91.5 (78.1-110.3) mg/L∙h with JN). The maximum ELF concentration was 10.4 (4.7-22.6) mg/L and 7.4 (6.2-10.3) mg/L, respectively. Conclusions: Based on our results, JN might be considered a viable alternative to the theoretically superior VMN. Therapeutic drug monitoring in the ELF can be advised due to the observed low exposure, high variability, and appreciable systemic absorption.

Abstract 3851: Microenvironmental alterations co-occur with mosaic somatic clonal expansions in normal tissues

Clonal hematopoiesis confers an increased risk for myeloid neoplasia, but progression to cancer requires additional alterations. Recently described clonal expansion (CE) of mutant skin and esophagus suggests CE is pervasive across tissues. Immune evasion and angiogenesis, reliant on the microenvironment (ME), are cancer hallmarks, yet ME changes in the setting of CE have not been systematically studied. Using GTEX RNA-Seq data (25 normal tissues, n = 6,511), previously reported somatic variants (Yizhak K, Science 2019) and normalized gene expression values were downloaded. Samples were grouped by the presence of: non-synonymous mutation (NSM) in a COSMIC Cancer Gene Census gene (CGC-m), NSM in a non-cancer gene or no NSM (non-m). ME scores, i.e. stromal and immune cell abundances for all samples, were estimated using Xcell and CIBERSORTx. Our analyses focused on tissues with at least 10 CGC-m, especially skin and esophagus which had the most CGC-m cases (77/600, 12% and 166/512, 32% respectively; median :4.6%). We also compared ME scores from skin and esophagus with corresponding cancer data from TCGA. Differential gene expression (DEG) testing between CGC-m and non-m samples, Gene Set Enrichment Analysis (GSEA), and hypoxia scores (Bhandari V, Nature Comm 2020) based on findings (below) were generated. ME scores significantly differed in the CGC-m vs. non-m cohorts, with increased epithelial and lymphatic endothelial cells (skin, esophagus), megakaryocytes (skin, prostate) and neutrophils (prostate, lung) (Wilcoxon FDR p-value &lt; 0.01). Skin showed reduced fibroblasts and esophagus, increased endothelial cells and melanocytes and lower pericytes and erythrocytes. Comparing TCGA and GTEX data, melanoma showed similar but more marked epithelial cell increase and fibroblast reduction. Esophageal carcinoma showed similar but more pronounced reductions in pericytes and erythrocytes. DEG testing between CGC-m and non-m identified: in esophagus, overexpression of genes aberrant in carcinomas (ERBB2, CDH1, SOX2 and TP63; p-adjusted &lt; 0.01), downregulation of pro-angiogenic factors and those involved in pericyte recruitment (FGF2, ANGPT1 and PDGFB); in skin, extracellular matrix protein, ELN was overexpressed. GSEA analysis of differentially expressed genes identified dysregulation of mesenchymal-epithelial transition and myogenesis pathways in both tissues and angiogenesis-related pathway in esophagus. Hypoxia scores were markedly higher in CGC-m vs. non-m esophagus samples (Wilcoxon FDR p-value &lt; 0.01). These results suggest ME alterations participate in initial stages of cancer progression and are tissue-specific. High hypoxia scores support a hypothesis of its early initiating role in CE-related angiogenesis in esophagus. Studying these changes may reveal novel avenues for early cancer intervention, immune or other targeted therapies and enhancement of conventional therapies.

Citation Format: Chetan Munugala, Jieting Hu, Eirini Christodoulou, Venkata Yellapantula. Microenvironmental alterations co-occur with mosaic somatic clonal expansions in normal tissues [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3851.

Abstract 541: Evaluation of low-pass whole genome sequencing for the diagnosis and monitoring of patients with pediatric solid tumors

Liquid biopsy assays based on sequence analysis of cell-free circulating tumor DNA (cfDNA) have the potential to transform patient care. Recent advances, however, have primarily focused on adult patients with solid tumors from whom access to sufficient volumes of blood, urine or other bodily fluids is not a barrier to testing. For pediatric cancer patients, noninvasive procedures are of paramount importance for early diagnosis as well as effective monitoring of disease, but clinical diagnostic tests need to be optimized for low volumes of blood. Furthermore, most childhood solid tumors have a limited number of driver mutations that can be interrogated by targeted next generation sequencing (NGS) panels. We evaluated analysis of liquid biopsy using Low-Pass Whole Genome Sequencing (LP-WGS) of plasma cfDNA as a potential approach for diagnosing and monitoring pediatric solid tumors. We profiled samples from 42 patients with a variety of solid tumors including sarcoma (n = 28), germ-cell (n = 4), and renal tumors ( n = 10). cfDNA was extracted with the MagMax cell-free total nucleic acid extraction kit from 4-6ml peripheral blood collected in EDTA tubes at the time of diagnosis (if available), during and after chemotherapy, and when available, at relapse. Whole-genome sequencing libraries were constructed with the xGen Prism DNA Library Prep Kit using 5ng of cfDNA and paired-end sequenced on an Illumina NextSeq 500 at an average of 1x depth of coverage. Data was analyzed using iChor software. The LP-WGS data from the cfDNA samples was compared with copy number alteration (CNA) profiles of the primary tumors generated from clinical chromosomal microarray analysis (CMA) (CytoScanHD or OncoScan). The CNA profiles detected in plasma using LP-WGS were very similar to those of the primary tumors observed by CMA. Of 42 patients analyzed to date, 19 had non-informative profiles either at diagnosis or relapse. The loss of 9p and 17p, including CDKN2A and TP53 respectively, were the most common pathogenic CNAs detected in the abnormal cases. One patient’s germ cell tumor profiled with our OncoKids NGS panel had a confirmed KRAS mutation and 12p amplification that were also detected by LP-WGS in the liquid biopsy. Marked genomic instability characteristic of osteosarcoma was readily detectable by LP-WGS and an indication of response to therapy was mirrored by the absence of CNAs in the liquid biopsy specimen after treatment. Combined, these data suggest that liquid biopsy with LP-WGS may be used to monitor pediatric patients with solid tumors, from diagnosis through treatment and recurrence.

Citation Format: Eirini Christodoulou, Dejerianne Ostrow, Anya Zdanowicz, Venkata Yellapantula, Cameron O'Connell, Moiz Bootwalla, Pan Yachen, Jennifer Cotter, James Amatruda, Leo Mascarenhas, Fariba Navid, Gai Xiaowu, Jaclyn Biegel. Evaluation of low-pass whole genome sequencing for the diagnosis and monitoring of patients with pediatric solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 541.

OTHR-23. Development of a cerebrospinal fluid liquid biopsy platform in pediatric patients with central nervous system tumors

Pediatric central nervous system (CNS) tumors carry high morbidity and mortality. The advent of targeted agents is aiming to change that through individualized, less invasive, and real-time molecular profiling. We successfully developed a cerebrospinal fluid (CSF) liquid biopsy (LB) platform combining low-pass whole genome sequencing (WGS) and targeted mutation and gene fusion analysis of cell-free (cf) DNA. WGS libraries were constructed with the xGen Prism DNA Library Prep Kit using 5ng of input cfDNA and paired-end sequenced (Illumina NextSeq 500) for an average 0.5x coverage across the genome. Copy number (CN) profiles were analyzed using the ichorCNA R package and compared with CN abnormalities of the primary tumors detected with CytoScanHD or Oncoscan arrays. Selected cases were analyzed for mutations or gene fusions using a custom glioma hybrid capture-based panel (Twist Bioscience) sequenced to 500-1000x across targeted regions. Mutations identified in LBs were compared with primary tumor OncoKids NGS panel results. CSF LBs from 44 tumor cases and 15 non-tumor controls were analyzed. Sixteen primary tumors had copy number changes, 10 had cfDNA detected in the LB across various primary tumor diagnoses (AT/RT, diffuse midline glioma, ependymoma, high-grade glioma, medulloblastoma, pilocytic astrocytoma). Four primary tumors had sequence alterations from the custom panel, two with detectable cfDNA (diffuse midline glioma H3K27M variant allele frequency (VAF) 49% and low-grade glioma BRAFV600E VAF 1.7%). Three patients had TP53 variants detected, all ultimately germline. Controls were negative across WGS and hybrid gene capture. Tumor DNA is detectable by both WGS and hybrid gene capture. Various histologic subtypes are detectable including embryonal and glioneuronal. CSF seems more enriched for cfDNA in high grade versus low grade tumors. These data suggest that NGS-based LB assays may be used to monitor pediatric patients with a variety of CNS tumors, from diagnosis through treatment and recurrence.

m.3685T>C is a Novel Mitochondrial DNA Variant That Causes Leigh Syndrome

Variants in the mitochondrial genome can result in dysfunction of Complex I within the electron transport chain, thus causing disruptions in oxidative phosphorylation. Pathogenic variants in the MT-ND1 (NADH:ubiquinone oxidoreductase core subunit 1) gene that result in Complex I dysfunction are a known cause of Leigh syndrome. The patient is a 4-yr-old female who initially presented with generalized tonic–clonic seizures, with other symptoms of Leigh syndrome becoming apparent after the seizures. A three-generation pedigree revealed no family history of mitochondrial disorders. Laboratory studies were remarkable for elevated blood lactate, alanine, and GDF15. T₂-weighted magnetic resonance imaging (MRI) revealed bilateral asymmetric signal hyperintensities in the basal ganglia, specifically in the bilateral putamen and right caudate. Magnetic resonance spectroscopy showed regionally elevated glucose and lactate. Mitochondrial respiratory chain enzyme analysis on skin fibroblasts demonstrated slightly reduced Complex I function. A 16-gene dystonia panel and chromosomal microarray analysis did not identify any disease-causing variants. Combined exome and mitochondrial genome sequencing identified the m.3685T > C (MT-ND1 p.Tyr127His) variant with 62.3% heteroplasmy with no alternative cause for the patient's condition. Mitochondrial genome sequencing of the mother demonstrated that the m.3685T > C variant occurred de novo. The m.3685T > C variant is absent from population databases. The tyrosine 127 residue is highly conserved, and several nearby pathogenic variants in the MT-ND1 gene have been previously associated with Leigh syndrome. We propose that the m.3685T > C variant is a novel mitochondrial DNA variant that causes Leigh syndrome, and we classify this variant as likely pathogenic based on currently available information.

Nasal powders of quercetin-β-cyclodextrin derivatives complexes with mannitol/lecithin microparticles for Nose-to-Brain delivery: In vitro and ex vivo evaluation

Quercetin, a flavonoid with possible neuroprotective action has been recently suggested for the early-stage treatment of Alzheimer's disease. The low solubility and extended first pass effect render quercetin unsuitable for oral administration. Alternatively, brain targeting is more feasible with nasal delivery, by-passing, non-invasively, Blood-Brain Barrier and ensuring rapid onset of action. Aiming to increase quercetin's disposition into brain, nasal powders consisting of quercetin-cyclodextrins (methyl-β-cyclodextrin and hydroxypropyl-β-cyclodextrin) lyophilizates blended with spray-dried microparticles of mannitol/lecithin were prepared. Quercetin's solubility at 37 °C and pH 7.4 was increased 19-35 times when complexed with cyclodextrins. Blending lyophilizates in various ratios with mannitol/lecithin microparticles, results in powders with improved morphological characteristics as observed by X-ray Diffraction and Scanning Electron Microscopy analysis. In vitro characterization of these powders using Franz cells, revealed rapid dissolution and permeation 17 (methyl-β-cyclodextrin) to 48 (hydroxypropyl-β-cyclodextrin) times higher than that of pure quercetin. Ex vivo powders' transport across rabbit nasal mucosa was found more efficient in comparison with the pure Que. The overall better performance of quercetin-hydroxypropyl-β-cyclodextrin powders is confirmed by ex vivo experiments revealing amount of quercetin permeated ranging from 0.03 ± 0.01 to 0.22 ± 0.05 μg/cm² for hydroxypropyl-β-cyclodextrin and 0.022 ± 0.01 to 0.17 ± 0.04 μg/cm² for methyl-β-cyclodextrin powders, while the permeation of pure quercetin was negligible.

The cardiovascular-protective properties of saffron and its potential pharmaceutical applications: A critical appraisal of the literature

Saffron, the dried stigma of Crocus sativus L., is used in traditional medicine for its healing properties and the treatment of various pathological conditions. The present literature review aimed to summarize and evaluate the preclinical and clinical data regarding the protective effects and mechanisms of saffron and its main components (crocin, crocetin, safranal) on cardiovascular risk factors and diseases. Many in vitro and animal studies have been conducted implicating antioxidant, hypolipidemic, anti-diabetic, and antiinflammatory impact of saffron and its constituents. Notably, there is evidence of direct atherosclerosis regression and stabilization in valid atherosclerosis-prone animal models. However, current clinical trials have shown mostly weak effects of saffron and its constituents on cardiovascular risk factors: (a) Modest lowering of fasting blood glucose, without significant reduction of HbA1c in type 2 diabetic patients, (b) moderate/controversial hypolipidemic effects, (c) negligible hypotensive effect, and (d) inconsistent modification of metabolic syndrome parameters. There are important drawbacks in clinical trial design, including the absence of pharmacokinetic/pharmacodynamic tests, the wide variance of doses and cohorts' characteristics, the small number of patients, the short duration. Therefore, large, properly designed, high-quality clinical trials, focusing on specific conditions are required to evaluate the biological/pharmacological activities and firmly establish the clinical efficacy of saffron and its possible therapeutic uses in cardiovascular diseases.

Molecular Dynamics Protocols for the Study of Cyclodextrin Drug Delivery Systems

Hypertension treatment is a current therapeutic priority as there is a constantly increasing part of the population that suffers from this risk factor, which may lead to cardiovascular and encephalic episodes and eventually to death. A number of marketed medicines consist of active ingredients that may be relatively potent; however, there is plenty of room to enhance their pharmacological profile and therapeutic index by improving specific physicochemical properties. In this work, we focus on a class of blood pressure regulators, called sartans, and we present the computational scheme for the pharmacological improvement of irbesartan (IRB) as a representative example. IRB has been shown to exert increased pharmacological action compared with other sartans, but it appears to be highly lipophilic and violates Lipinski rule (MLogP >4.15). To circumvent this drawback, proper hydrophilic molecules, such as cyclodextrins, can be used as drug carriers. This chapter describes the combinatory use of computational methods, namely molecular docking, quantum mechanics, molecular dynamics, and free energy calculations, to study the interactions and the energetic contributions that govern the IRB:cyclodextrin association. We provide a detailed computational protocol, which aims to assist the improvement of the pharmacological properties of sartans. This protocol can also be applied to any other drug molecule with diminished hydrophilic character.

Analysis of CRISPR-Cas9 screens identifies genetic dependencies in melanoma

Targeting the MAPK signaling pathway has transformed the treatment of metastatic melanoma. CRISPR-Cas9 genetic screens provide a genome-wide approach to uncover novel genetic dependencies that might serve as therapeutic targets. Here, we analyzed recently reported CRISPR-Cas9 screens comparing data from 28 melanoma cell lines and 313 cell lines of other tumor types in order to identify fitness genes related to melanoma. We found an average of 1,494 fitness genes in each melanoma cell line. We identified 33 genes, inactivation of which specifically reduced the fitness of melanoma. This set of tumor type-specific genes includes established melanoma fitness genes as well as many genes that have not previously been associated with melanoma growth. Several genes encode proteins that can be targeted using available inhibitors. We verified that genetic inactivation of DUSP4 and PPP2R2A reduces the proliferation of melanoma cells. DUSP4 encodes an inhibitor of ERK, suggesting that further activation of MAPK signaling activity through its loss is selectively deleterious to melanoma cells. Collectively, these data present a resource of genetic dependencies in melanoma that may be explored as potential therapeutic targets.

External validation of models to predict the outcome of pregnancies of unknown location: a multicentre cohort study

Objective

To validate externally five approaches to predict ectopic pregnancy (EP) in pregnancies of unknown location (PUL): the M6P and M6NP risk models, the two‐step triage strategy (2ST, which incorporates M6P), the M4 risk model, and beta human chorionic gonadotropin ratio cut‐offs (BhCG‐RC).

Design

Secondary analysis of a prospective cohort study.

Setting

Eight UK early pregnancy assessment units.

Population

Women presenting with a PUL and BhCG >25 IU/l.

Methods

Women were managed using the 2ST protocol: PUL were classified as low risk of EP if presenting progesterone ≤2 nmol/l; the remaining cases returned 2 days later for triage based on M6P. EP risk ≥5% was used to classify PUL as high risk. Missing values were imputed, and predictions for the five approaches were calculated post hoc. We meta‐analysed centre‐specific results.

Main outcome measures

Discrimination, calibration and clinical utility (decision curve analysis) for predicting EP.

Results

Of 2899 eligible women, the primary analysis excluded 297 (10%) women who were lost to follow up. The area under the ROC curve for EP was 0.89 (95% CI 0.86–0.91) for M6P, 0.88 (0.86–0.90) for 2ST, 0.86 (0.83–0.88) for M6NP and 0.82 (0.78–0.85) for M4. Sensitivities for EP were 96% (M6P), 94% (2ST), 92% (N6NP), 80% (M4) and 58% (BhCG‐RC); false‐positive rates were 35%, 33%, 39%, 24% and 13%. M6P and 2ST had the best clinical utility and good overall calibration, with modest variability between centres.

Conclusions

2ST and M6P performed best for prediction and triage in PUL.

Tweetable abstract

The M6 model, as part of a two‐step triage strategy, is the best approach to characterise and triage PULs.

The M6 model, as part of a two‐step triage strategy, is the best approach to characterise and triage PULs.

Antihypertensive activity and molecular interactions of irbesartan in complex with 2-hydroxypropyl-β-cyclodextrin

Irbesartan (IRB) exerts beneficial effects either alone or in combination with other drugs on numerous diseases, such as cancer, diabetes, and hypertension. However, due to its high lipophilicity, IRB does not possess the optimum pharmacological efficiency. To circumvent this problem, a drug delivery system with 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD) was explored. The 1:1 complex between IRB and 2-HP-β-CD was identified through ESI QTF HRMS. Dissolution studies showed a higher dissolution rate of the lyophilized IRB-2-HP-β-CD complex than the tablet containing IRB at pH = 1.2. DSC results revealed the differences of the thermal properties between the complex and various mixtures consisting of the two components, namely IRB and 2-HP-β-CD. Interestingly, depending on the way the mixture preparation was conducted, different association between the two components was observed. Molecular dynamics (MD) simulations predicted the favorable formation of the above complex and identified the dominant interactions between IRB and 2-HP-β-CD. In vitro pharmacological results verified that the inclusion complex not only preserves the binding affinity of IRB for AT1R receptor, but also it slightly increases it. As the complex formulation lacks the problems of the tablet, our approach is a promising new way to improve the efficiency of IRB.

Charting the structural and thermodynamic determinants in phenolic acid natural product - cyclodextrin encapsulations

Cyclodextrins are pliable platforms that have served to optimize the pharmaceutic profile of numerous compounds and to enhance the stability of natural food additives. Caffeic and rosmarinic acid are natural products with proven health benefits, though their full therapeutic potential has not been exploited. To enhance their pharmaceutic profile, we developed cyclodextrin-based formulates and unveiled their thermodynamic and structural principles. The complexes' stoichiometry was determined by ESI-MS. Solid-state and liquid NMR spectroscopy revealed the interactions and the topographical location of the caffeic and rosmarinic acid inside the cyclodextrin cavity. The theoretically analyzed HP-β-CD's degree of substitution (DS) of caffeic and rosmarinic acids can explain the intensities obtained by 2D NOESY experiments. The thermodynamics and the affinity of the complexes were evaluated through isothermal titration calorimetry. In addition, the rosmarinic and caffeic acids as, also, their complexes showed considerable antimicrobial activity against common food spoilage and pathogenic bacteria. The generated data could provide the basis to understand the structural and thermodynamic determinants implicated in natural products - CD recognition and to develop platforms for the optimization of their pharmaceutical and stability profiles in order to be utilized as safe and stable natural antimicrobial food additives.Communicated by Ramaswamy H. Sarma.

Triaging women with pregnancy of unknown location using two-step protocol including M6 model: clinical implementation study

OBJECTIVE

The M6 risk-prediction model was published as part of a two-step protocol using an initial progesterone level of ≤ 2 nmol/L to identify probable failing pregnancies (Step 1) followed by the M6 model (Step 2). The M6 model has been shown to have good triage performance for stratifying women with a pregnancy of unknown location (PUL) as being at low or high risk of harboring an ectopic pregnancy (EP). This study validated the triage performance of the two-step protocol in clinical practice by evaluating the number of protocol-related adverse events and how effectively patients were triaged.

METHODS

This was a prospective multicenter interventional study of 3272 women with a PUL, carried out between January 2015 and January 2017 in four district general hospitals and four university teaching hospitals in the UK. The final pregnancy outcome was defined as: a failed PUL (FPUL), an intrauterine pregnancy (IUP) or an EP (including persistent PUL (PPUL)). FPUL and IUP were grouped as low-risk and EP/PPUL as high-risk PUL. Serum progesterone and human chorionic gonadotropin (hCG) levels were measured at presentation in all patients. If the initial progesterone level was ≤ 2 nmol/L, patients were discharged and were asked to have a follow-up urine pregnancy test in 2 weeks to confirm a negative result. If the progesterone level was > 2 nmol/L or a measurement had not been taken, hCG level was measured again at 48 h and results were entered into the M6 model. Patients were managed according to the outcome predicted by the protocol. Those classified as 'low risk, probable FPUL' were advised to perform a urine pregnancy test in 2 weeks and those classified as 'low risk, probable IUP' were invited for a scan a week later. When a woman with a PUL was classified as high risk (i.e. risk of EP ≥ 5%) she was reviewed clinically within 48 h. One center used a progesterone cut-off of ≤ 10 nmol/L and its data were analyzed separately. If the recommended management protocol was not adhered to, this was recorded as a protocol deviation and classified as: unscheduled visit for clinician reason, unscheduled visit for patient reason or incorrect timing of blood test or ultrasound scan. The classifications outlined in the UK Good Clinical Practice (GCP) guidelines were used to evaluate the incidence of adverse events. Data were analyzed using descriptive statistics.

RESULTS

Of the 3272 women with a PUL, 2625 were included in the final analysis (317 met the exclusion criteria or were lost to follow-up, while 330 were evaluated using a progesterone cut-off of ≤ 10 nmol/L). Initial progesterone results were available for 2392 (91.1%) patients. In Step 1, 407 (15.5%) patients were classified as low risk (progesterone ≤ 2 nmol/L), of whom seven (1.7%) were ultimately diagnosed with an EP. In 279 of the remaining 2218 women with a PUL, the M6 model was not applied owing to protocol deviation or because the outcome was already known (usually on the basis of an ultrasound scan) before a second hCG reading was taken; of these patients, 30 were diagnosed with an EP. In Step 2, 1038 women with a PUL were classified as low risk, of whom eight (0.8%) had a final outcome of EP. Of 901 women classified as high risk at Step 2, 275 (30.5%) had an EP. Therefore, 275/320 (85.9%) EPs were correctly classified as high risk. Overall, 1445/2625 PUL (55.0%) were classified as low risk, of which 15 (1.0%) were EP. None of these cases resulted in a ruptured EP or significant clinical harm. Sixty-two women participating in the study had an adverse event, but no woman had a serious adverse event as defined in the UK GCP guidelines.

CONCLUSIONS

This study has shown that the two-step protocol incorporating the M6 model effectively triaged the majority of women with a PUL as being at low risk of an EP, minimizing the follow-up required for these patients after just two visits. There were few misclassified EPs and none of these women came to significant clinical harm or suffered a serious adverse clinical event. The two-step protocol incorporating the M6 model is an effective and clinically safe way of rationalizing the management of women with a PUL. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

NEK11 as a candidate high-penetrance melanoma susceptibility gene

BACKGROUND

A proportion of patients diagnosed with cutaneous melanoma reports a positive family history. Inherited variants in CDKN2A and several other genes have been shown to predispose to melanoma; however, the genetic basis of familial melanoma remains unknown in most cases. The objective of this study was to provide insight into the genetic basis of familial melanoma.

METHODS

In order to identify novel melanoma susceptibility genes, whole exome sequencing (WES) analysis was applied in a Dutch family with melanoma. The causality of a candidate variant was characterised by performing cosegregation analysis in five affected family members using patient-derived tissues and digital droplet PCR analysis to accurately quantify mutant allele frequency. Functional in-vitro studies were performed to assess the pathogenicity of the candidate variant.

RESULTS

Application of WES identified a rare, nonsense variant in the NEK11 gene (c.1120C>T, p.Arg374Ter), cosegregating in all five affected members of a Dutch family. NEK11 (NIMA-related Kinase 11) is involved in the DNA damage response, enforcing the G2/M cell cycle checkpoint. In a melanoma from a variant carrier, somatic loss of the wildtype allele of this putative tumour suppressor gene was demonstrated. Functional analyses showed that the NEK11 p.Arg374Ter mutation results in strongly reduced expression of the truncated protein caused by proteasomal degradation.

CONCLUSION

The NEK11 p.Arg374Ter variant identified in this family leads to loss-of-function through protein instability. Collectively, these findings support NEK11 as a melanoma susceptibility gene.

Assessing a single SNP located at TERT/CLPTM1L multi-cancer risk region as a genetic modifier for risk of pancreatic cancer and melanoma in Dutch CDKN2A mutation carriers

Carriers of pathogenic variants in CDKN2A have a 70% life-time risk of developing melanoma and 15–20% risk of developing pancreatic cancer (PC). In the Netherlands, a 19-bp deletion in exon 2 of CDKN2A (p16-Leiden mutation) accounts for most hereditary melanoma cases. Clinical experience suggests variability in occurrence of melanoma and PC in p16-Leiden families. Thereby, the risk of developing cancer could be modified by both environmental and genetic contributors, suggesting that identification of genetic modifiers could improve patients’ surveillance. In a recent genome-wide association study (GWAS), rs36115365-C was found to significantly modify risk of PC and melanoma in the European population. This SNP is located on chr5p15.33 and has allele-specific regulatory activities on TERT expression. Herein, we investigated the modifying capacities of rs36115365-C on PC and melanoma in a cohort of 283 p16-Leiden carriers including 29 diagnosed with PC, 171 diagnosed with melanoma, 21 diagnosed with both PC and melanoma and 62 with neither PC nor melanoma. In contrast to previously reported findings, we did not find a significant association of PC risk with risk variant presence as determined by Generalized Estimating Equations (GEE) modelling. Interestingly, carrier-ship of the risk variant had a significant protective effect for melanoma (OR − 0.703 [95% CI − 1.201 to − 0.205], p = 0.006); however, the observed association was no longer significant after exclusion of probands to assess possible influence of ascertainment. Collectively, genetic modifiers for the prediction of PC and melanoma risk in p16-Leiden carriers remain to be determined.

Host-Guest Interactions between Candesartan and Its Prodrug Candesartan Cilexetil in Complex with 2-Hydroxypropyl-β-cyclodextrin: On the Biological Potency for Angiotensin II Antagonism

Renin-angiotensin aldosterone system inhibitors are for a long time extensively used for the treatment of cardiovascular and renal diseases. AT1 receptor blockers (ARBs or sartans) act as antihypertensive drugs by blocking the octapeptide hormone Angiotensin II to stimulate AT1 receptors. The antihypertensive drug candesartan (CAN) is the active metabolite of candesartan cilexetil (Atacand, CC). Complexes of candesartan and candesartan cilexetil with 2-hydroxylpropyl-β-cyclodextrin (2-HP-β-CD) were characterized using high-resolution electrospray ionization mass spectrometry and solid state ¹³C cross-polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR) spectroscopy. The ¹³C CP/MAS results showed broad peaks especially in the aromatic region, thus confirming the strong interactions between cyclodextrin and drugs. This experimental evidence was in accordance with molecular dynamics simulations and quantum mechanical calculations. The synthesized and characterized complexes were evaluated biologically in vitro. It was shown that as a result of CAN's complexation, CAN exerts higher antagonistic activity than CC. Therefore, a formulation of CC with 2-HP-β-CD is not indicated, while the formulation with CAN is promising and needs further investigation. This intriguing result is justified by the binding free energy calculations, which predicted efficient CC binding to 2-HP-β-CD, and thus, the molecule's availability for release and action on the target is diminished. In contrast, CAN binding was not favored, and this may allow easy release for the drug to exert its bioactivity.

Preparation, chemical characterization and determination of crocetin's pharmacokinetics after oral and intravenous administration of saffron (Crocus sativus L.) aqueous extract to C57/BL6J mice

OBJECTIVES

To prepare a lyophilized saffron aqueous extract (SFE) and determine its chemical profile and serum and tissue pharmacokinetics after intravenous and oral administration to C57/Bl6J mice.

METHODS

Lyophilized SFE was prepared, characterized using semi-preparative HPLC and NMR analysis, and stability studies at room temperature, and was quantified for crocin content with an HPLC-PDA method. After intravenous and oral administration of SFE (60 mg/kg, reconstituted with water for injection) to C57/Bl6J mice, crocetin (derived from in vivo crocin hydrolysis) serum and tissue levels (unconjugated and total) were measured with an HPLC-PDA method and subjected to compartmental and non-compartmental PK analysis.

KEY FINDINGS

Saffron aqueous extract was rich in all-trans-crocin (27.8 ± 0.1% w/w) and stable for more than 15 months. One-compartment PK model described crocetin's (unconjugated) kinetics after intravenous administration of SFE, while a first-order kinetic parameter described the rate of crocetin biotransformation to crocetin metabolite (conjugated). Α οne-compartment PK model with first-order absorption described crocetin and crocetin's metabolite kinetics after SFE oral administration. Relative oral bioavailability was calculated at 1.17 for total crocetin. Tissue NCA PK analysis revealed extensive crocetin distribution to liver and kidneys.

CONCLUSIONS

SFE is a stable lyophilized extract rich in all-trans-crocin. The PK study allowed the estimation of basic PK parameters and the bioavailability of SFE's main bioactive component, crocetin, after peros administration.

Silibinin Improves TNF-α and M30 Expression and Histological Parameters in Rat Kidneys After Hepatic Ischemia/Reperfusion

BACKGROUND

Remote kidney damage is a sequel of hepatic ischemia-reperfusion (I/R) injury. Silibinin is the main ingredient of the milk thistle plant seed extract with known antioxidant and hepatoprotective activity. Our study investigates the nephroprotective potential of intravenously administered silibinin, as a lyophilized SLB-hydoxypropyl-beta-cyclodextrin product, in hepatic I/R injury.

MATERIAL AND METHODS

63 Wistar rats were divided into three groups: Sham (virtual intervention); Control (45 min ischemia and reperfusion); and Silibinin (200 μL intravenous silibinin administration after 45 min of ischemia). Kidney tissues were collected to determine TNF-α, M30 and histopathological changes at predetermined time intervals.

RESULTS

Comparing Sham vs. Control groups, proved that hepatic I/R injury increased renal TNF-α and M30 expression. Deterioration was observed in hyperemia/filtration of renal parenchyma and tubules, cortical filtration, tubular necrosis and edema (tissue swelling index). Intravenous silibinin administration and comparison of the Control vs. Silibinin groups showed a statistically significant decrease in TNF-α levels at 240 min following I/R (p < 0.0001), and in M30 at 180 min (p = 0.03) and 240 min (p < 0.0001). Renal parameters have significantly decreased in: hyperemia/filtration of renal parenchyma at 120 min (p = 0.003), 180 min (p = 0.0001) and 240 min (p = 0.0002); hyperemia/filtration of renal tubules at 120 min (p = 0.02), 180 min (p = 0.0001) and 240 min (p = 0.0005); cortical filtration (240 min - p = 0.005); tubular necrosis (240 min - p = 0.021); and edema (240 min - p = 0.001).

CONCLUSION

Our study confirms that hepatic I/R injury causes remote renal damage while the intravenous administration of silibinin leads to statistically significant nephroprotective action.

Saffron (Crocus sativus) intake provides nutritional preconditioning against myocardial ischemia-reperfusion injury in Wild Type and ApoE(-/-) mice: Involvement of Nrf2 activation

BACKGROUND AND AIMS

Saffron is an antioxidant herbal derivative; however, its efficacy as a nutritional cardioprotective agent has not been fully elucidated. We investigated the cardioprotective properties of a standardized saffron aqueous extract (SFE) against ischemia/reperfusion (I/R) injury in Wild-Type (WT) and ApoE^(-/-) mice and the underlying molecular mechanisms.

METHODS AND RESULTS

WT and ApoE^(-/-) mice were subjected to 30 min I and 2 h R, with the following per os interventions for 4 weeks: 1) WT Control Group, receiving Water for Injection (WFI); 2) WT Crocus Group, receiving SFE at a dose of 60 mg/kg/day; 3) WT Crocus + Wort group, receiving SFE as described above and wortmannin at a dose of 60 μg/kg bolus 15 min before R; 4) ApoE^(-/-) Control Group, receiving WFI; 5) ApoE^(-/-) Crocus Group, receiving SFE at a dose of 60 mg/kg/day and 6) ApoE^(-/-) Crocus + Wort: receiving SFE as described above and wortmannin at a dose of 60 μg/kg bolus, 15 min before R. Ischemic area/area at risk (I/R%) ratio was measured. Blood samples and ischemic myocardial tissue were collected at the 10th min of reperfusion for assessment of troponin I, malondialdehyde (MDA), nitrotyrosine (NT), p-eNOS, eNOS, p-Akt, Akt, p-p42/p-p44, p-GSK3β, GSK3β, IL-6, Nrf2, HO-1 and MnSOD expression. The effect of SFE on Nrf2 expression was also evaluated in vitro. SFE reduced infarct size in WT (16.15 ± 3.7% vs 41.57 ± 2.48%, ***p < 0.001) and in ApoE^(-/-) mice (16.14 ± 1.47% vs 45.57 ± 1.73%, ***p < 0.001). The administration of wortmannin resulted in partial inhibition of the infarct size limitation efficacy of SFE (in both WT and Apo-E^(-/-) mice). Mice receiving SFE showed increased levels of eNOS, p-Akt, p-ERK1/2, p-44/p-42 and p-GSK3β-Ser9 and reduced expression of IL-6 and iNOS; furthermore, SFE reduced the levels of MDA and NT. SFE induced Nrf2 expression and its downstream targets, HO-1 and MnSOD in the myocardium of the treated animals, and induced Nrf2 expression in vitro in a dose-dependent manner.

CONCLUSIONS

SFE limits myocardial infarction in Wild-Type and ApoE^(-/-) mice in a multifaceted manner including activation of Akt/eNOS/ERK1/2/GSK3-β and through Nrf2 pathway, bestowing antioxidant protection against I/R.

Exploring the interactions of irbesartan and irbesartan-2-hydroxypropyl-β-cyclodextrin complex with model membranes

The interactions of irbesartan (IRB) and irbesartan-2-hydroxypropyl-β-cyclodextrin (HP-β-CD) complex with dipalmitoyl phosphatidylcholine (DPPC) bilayers have been explored utilizing an array of biophysical techniques ranging from differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), ESI mass spectrometry (ESI-MS) and solid state nuclear magnetic resonance (ssNMR). Molecular dynamics (MD) calculations have been also conducted to complement the experimental results. Irbesartan was found to be embedded in the lipid membrane core and to affect the phase transition properties of the DPPC bilayers. SAXS studies revealed that irbesartan alone does not display perfect solvation since some coexisting irbesartan crystallites are present. In its complexed form IRB gets fully solvated in the membranes showing that encapsulation of IRB in HP-β-CD may have beneficial effects in the ADME properties of this drug. MD experiments revealed the topological and orientational integration of irbesartan into the phospholipid bilayer being placed at about 1nm from the membrane centre.

Saffron: a natural product with potential pharmaceutical applications

OBJECTIVES

Recently, a great deal of interest has been developed to isolate and investigate novel bioactive components from natural resources with health beneficial effects. Saffron is the dried stigma of Crocus sativus L. and has been used for centuries in traditional medicine mainly for its healing properties, as well as for the treatment of various pathological conditions. Objectives of the present review are to unravel its therapeutic properties and investigate the potential applications of saffron in contemporary therapy of a wide spectrum of diseases and summarize previous and current evidence regarding the biological/pharmacological activities of saffron and its active ingredients and their possible therapeutic uses.

KEY FINDINGS

Recent phytochemistry and pharmacological experiments have indicated that crocin and safranal, the major active ingredients of saffron, exert important actions, such as antioxidant, anti-tumor, anti-diabetic, anti-inflammatory and anti-atherosclerotic. Unfortunately, the vast majority of those data derive from in vitro studies, whereas a limited number of in vivo experiments support the aforementioned effects. In addition to studies with mechanistic implications, very few clinical trials provide preliminary evidence of saffron potentiality to alleviate depression and increase cognitive function in patients with Alzheimer's disease.

SUMMARY

The history and structural features of saffron constituents are given in the first part of the review, followed by a comprehensive and critical presentation of the published preclinical and clinical studies and review papers on the pharmacology and possible therapeutic uses of saffron and its main active components crocin and safranal.

Serum and tissue pharmacokinetics of silibinin after per os and i.v. administration to mice as a HP-β-CD lyophilized product

Silibinin, the main active component of Silybum marianum is a hepatoprotective and antioxidant agent with antitumor effect, exhibiting very low aqueous solubility and oral bioavailability limiting its use in therapeutics. We characterized serum and tissue pharmacokinetics of SLB, calculated its absolute bioavailability and developed an open loop physiologically based pharmacokinetic (PBPK) model, after oral (per os, p.o) and intravenous (i.v.) administration in mice as water-soluble silibinin-hydroxypropyl-beta-cyclodextrin (SLB-HP-β-CD) lyophilized product. 60 C57Bl/6J mice were divided into groups of 5, each group representing one sampling time point. SLB-HP-β-CD lyophilized product was administered orally (50mg/kg) and i.v. (20mg/kg) after reconstitution with water for injection. Blood and tissue samples were collected at selected time points after animal sacrificed, properly treated and analyzed with HPLC-PDA for non-metabolized and total SLB. NONMEM pharmacokinetic analysis revealed a 2-compartment PK model to describe serum SLB pharmacokinetics, with zero order absorption after oral administration and was applied as forcing function to an open loop PBPK model incorporating heart, liver, kidneys and lungs. Tissue/plasma Kp values were estimated using i.v. data and can be used to predict tissue SLB distribution after oral administration. Absolute oral bioavailability of SLB from the lyophilized SLB-HP-β-CD product was 10 times higher than after administration of pure SLB.

Raise the bar and lower the dose: current and future strategies for radiation dose reduction in head and neck imaging

SUMMARY

Technologic advances in CT have generated a dramatic increase in the number of CT studies, with a resultant increase in the radiation dose related to CT scanning. Such increase in radiation dose is becoming a concern for the radiology community, especially with increasing public awareness of the dose burden related to examinations. To cope with the increase in CT-related radiation exposure, it is becoming necessary to optimize CT imaging protocols and apply radiation dose reduction techniques to ensure the best imaging with the lowest radiation dose.

Quaternary structure of the human Cdt1-Geminin complex regulates DNA replication licensing

All organisms need to ensure that no DNA segments are rereplicated in a single cell cycle. Eukaryotes achieve this through a process called origin licensing, which involves tight spatiotemporal control of the assembly of prereplicative complexes (pre-RCs) onto chromatin. Cdt1 is a key component and crucial regulator of pre-RC assembly. In higher eukaryotes, timely inhibition of Cdt1 by Geminin is essential to prevent DNA rereplication. Here, we address the mechanism of DNA licensing inhibition by Geminin, by combining X-ray crystallography, small-angle X-ray scattering, and functional studies in Xenopus and mammalian cells. Our findings show that the Cdt1:Geminin complex can exist in two distinct forms, a "permissive" heterotrimer and an "inhibitory" heterohexamer. Specific Cdt1 residues, buried in the heterohexamer, are important for licensing. We postulate that the transition between the heterotrimer and the heterohexamer represents a molecular switch between licensing-competent and licensing-defective states.

Neuropeptide urocortin 1 and its receptors are expressed in the human liver

The corticotropin-releasing hormone (CRH) system, consisting of CRH, urocortins (Ucns), their receptors CRH(1) and CRH(2), and CRH-binding protein, holds the principal role in mediating the response to stress stimuli. Besides their expression in the brain, CRH neuropeptides and receptors have been found in multiple peripheral sites. We investigated the expression of the CRH system in the human liver, using RT-PCR and immunohistochemistry. Ucn 1 gene transcripts were amplified in all the human liver biopsies examined. Ucn 1 immunoreactivity was localized in hepatocytes. CRH(1) and CRH(2(alpha)) receptor gene expression was also found, and receptor protein had a similar distribution to Ucn 1. Finally, Ucn 1 and CRH receptor expression was demonstrated in hepatic biopsies from a variety of liver pathologies, including primary or metastatic liver carcinoma and cirrhosis. We conclude that the CRH system is expressed by human liver under normal and pathological conditions, Ucn 1 being the major ligand. Further study is required to unfold the biological role of these effectors in liver physiology and pathogenesis, as they may act in an autocrine manner through activation of the CRH receptors expressed locally.