Estimation of brain receptor occupancy for trazodone immediate release and once a day formulations

Trazodone is approved for the treatment of major depressive disorders, marketed as immediate release (IR), prolonged release, and once a day (OAD) formulation. The different formulations allow different administration schedules and may be useful to facilitate patients’ compliance to the antidepressant treatment. A previously verified physiologically‐based pharmacokinetic model based on in vitro and in vivo information on trazodone pharmacokinetics was applied, aiming at predicting brain receptor occupancy (RO) after single and repeated dosing of the IR formulation and repeated dosing of the OAD formulation in healthy subjects. Receptors included in the simulations were selected using static calculations of RO based on the maximum unbound brain concentration (C_max,brain,u) of trazodone for each formulation and dosing scheme, resulting in 16 receptors being simulated. Seven receptors were simulated for the IR low dose formulation (30 mg), with similar t _onset and duration of coverage (range: 0.09–0.25 h and 2.1–>24 h, respectively) as well as RO (range: 0.64–0.92) predicted between day 1 and day 7 of dosing. The 16 receptors evaluated for the OAD formulation (300 mg) showed high RO (range: 0.97–0.84 for the receptors also covered by the IR formulation and 0.73–0.48 for the remaining) correlating with affinity and similar duration of time above the target threshold to the IR formulation (range: 2–>24 h). The dose‐dependent receptor coverage supports the multimodal activity of trazodone, which may further contribute to its fast antidepressant action and effectiveness in controlling different symptoms in depressed patients.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

The antidepressant efficacy of trazodone has been shown to be significantly correlated to its steady‐state plasma levels, and previous work has shown some understanding of trazodone range of affinity for different receptors, at different doses, but without considering the different available formulations. Trazodone is commonly available as: immediate release (IR), prolonged release (PR), and once a day (OAD) tablets. The IR formulation has a rapid onset and short duration of action, whereas the PR formulation is characterized by an absorption boost as soon as it is administered and has a comparatively delayed maximum concentration (C_max). Conversely, the OAD formulation provides a controlled release of trazodone over 24 h without the early high peak plasma concentration seen with the IR and PR formulations.

• WHAT QUESTION DID THIS STUDY ADDRESS?

This work aims to identify the brain receptors reaching a threshold occupancy of 50% through static predictions and determine the occupancy versus time profile for those of interest following administration of short‐ and long‐acting trazodone formulations.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Brain receptor occupancy (RO) for key targets were predicted based on free drug concentrations, allowing for a physiologically relevant assessment of the different pathways affected by each formulation and dose.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

The presented physiologically‐based pharmacokinetic approach to assess RO can be used to guide formulation selection and dosing in clinical studies.     

A predictive microfluidic model of human glioblastoma to assess trafficking of blood–brain barrier-penetrant nanoparticles

The blood–brain barrier represents a significant challenge for the treatment of high-grade gliomas, and our understanding of drug transport across this critical biointerface remains limited. To advance preclinical therapeutic development for gliomas, there is an urgent need for predictive in vitro models with realistic blood–brain-barrier vasculature. Here, we report a vascularized human glioblastoma multiforme (GBM) model in a microfluidic device that accurately recapitulates brain tumor vasculature with self-assembled endothelial cells, astrocytes, and pericytes to investigate the transport of targeted nanotherapeutics across the blood–brain barrier and into GBM cells. Using modular layer-by-layer assembly, we functionalized the surface of nanoparticles with GBM-targeting motifs to improve trafficking to tumors. We directly compared nanoparticle transport in our in vitro platform with transport across mouse brain capillaries using intravital imaging, validating the ability of the platform to model in vivo blood–brain-barrier transport. We investigated the therapeutic potential of functionalized nanoparticles by encapsulating cisplatin and showed improved efficacy of these GBM-targeted nanoparticles both in vitro and in an in vivo orthotopic xenograft model. Our vascularized GBM model represents a significant biomaterials advance, enabling in-depth investigation of brain tumor vasculature and accelerating the development of targeted nanotherapeutics.

High-grade gliomas are the most common primary malignant brain tumors in adults (1). These include grade IV astrocytomas, commonly known as glioblastoma multiforme (GBM), which account for more than 50% of all primary brain cancers and have dismal prognoses, with a 5-y survival rate of less than 5% (2). Due to their infiltrative growth into the healthy brain tissue, surgery often fails to eradicate all tumor cells (3). While chemotherapy and radiation modestly improve median survival (4), most patients ultimately succumb to their tumors. This is primarily due to the presence of a highly selective and regulated endothelium between blood and brain parenchyma known as the blood–brain barrier (BBB) (5), which limits the entry of therapeutics into the brain tissue where tumors are located. The BBB, characterized by a unique cellular architecture of endothelial cells (ECs), pericytes (PCs), and astrocytes (ACs) (6, 7), displays up-regulated expression of junctional proteins and reduced paracellular and transcellular transports compared to other endothelia (8). While this barrier protects the brain from toxins and pathogens, it also severely restricts the transport of many therapeutics, as evidenced by the low cerebrospinal fluid (CSF)-to-plasma ratio of most chemotherapeutic agents (9). There is thus an important need to develop new delivery strategies to cross the BBB and target tumors, enabling sufficient drug exposure (10).Despite rigorous research efforts to develop effective therapies for high-grade gliomas, the majority of trialed therapeutics have failed to improve outcomes in the clinic, even though the agents in question are effective against tumor cells in preclinical models (11). This highlights the inability of current preclinical models to accurately predict the performance of therapeutics in human patients. To address these limitations, we developed an in vitro microfluidic model of vascularized GBM tumors embedded in a realistic human BBB vasculature. This BBB-GBM platform features brain microvascular networks (MVNs) in close contact with a GBM spheroid, recapitulating the infiltrative properties of gliomas observed in the clinic (12) and those of the brain tumor vasculature, with low permeability, small vessel diameter, and increased expression of relevant junctional and receptor proteins (7). This platform is well suited for quantifying vascular permeability of therapeutics and simultaneously investigating modes of transport across the BBB and into GBM tumor cells.There is strong rationale for developing therapeutic nanoparticles (NPs) for GBM and other brain tumors, as they can be used to deliver a diverse range of therapeutic agents and, with appropriate functionalization, can be designed to exploit active transport mechanisms across the BBB (13, 14). Liposomal NPs have been employed in the oncology clinic to improve drug half-life and decrease systemic toxicity (15), but, to date, no nanomedicines have been approved for therapeutic indications in brain tumors. We hypothesize that a realistic BBB-GBM model composed entirely of human cells can accelerate preclinical development of therapeutic NPs. Using our BBB-GBM model, we investigated the trafficking of layer-by-layer NPs (LbL-NPs) and ultimately designed a GBM-targeted NP. The LbL approach leverages electrostatic assembly to generate modular NP libraries with highly controlled architecture. We have used LbL-NPs to deliver a range of therapeutic cargos in preclinical tumor models (16, 17) and have recently demonstrated that liposomes functionalized with BBB-penetrating ligands improved drug delivery across the BBB to GBM tumors (18). Consistent with clinical data (19), we observed that the low-density lipoprotein receptor-related protein 1 (LRP1) was up-regulated in the vasculature near GBM spheroids in the BBB-GBM model and leveraged this information to design and iteratively test a library of NPs. We show that the incorporation of angiopep-2 (AP2) peptide moieties on the surface of LbL-NPs leads to increased BBB permeability near GBM tumors through LRP1-mediated transcytosis. With intravital imaging, we compared the vascular permeabilities of dextran and LbL-NPs in the BBB-GBM platform to those in mouse brain capillaries and validated the predictive potential of our in vitro model. Finally, we show the capability of the BBB-GBM platform to screen therapeutic NPs and predict in vivo efficacy, demonstrating improved efficacy of cisplatin (CDDP) when encapsulated in GBM-targeting LbL-NPs both in vitro and in vivo.     

Vaccine coverage in children born to migrant mothers in Australia: A population-based cohort study

BackgroundOverall, infant immunisation coverage is currently >90% in Australia, but there are pockets of under-immunised children including children from migrant backgrounds. This study aimed to examine whether on-time vaccination coverage of diphtheria-tetanus-pertussis dose 3 (DTP3) for children born in Australia differed by mother’s region of birth and if so, what factors were associated with these differences.MethodsWe conducted a population-based cohort study using linked data on perinatal, immunisation and birth records for 2 million children born in Western Australia and New South Wales between 1996 and 2012. We assessed on-time coverage of DTP3 (vaccination from 2 weeks prior to, and up until 30 days after, the due date) in children with mothers born overseas. Logistic regression models were developed to determine factors associated with on-time coverage for each maternal region of birth and all regions combined, adjusting for a range of demographic factors. Adjusted estimates of coverage were calculated for the different regions of birth.ResultsOn-time DTP3 coverage was 76.2% in children of Australian born mothers, lower in children of mothers from Oceania (66.7%) and North America (68%), and higher in children born to mothers from South-East Asia (79.9%) and Southern Asia (79.3%). While most variables were consistently associated with lower coverage in all regions of birth, higher socioeconomic status and jurisdiction of birth showed varied results. Adjusted estimates of DTP3 coverage increased in children born to mothers from Australia (78.3%), Oceania (70.5%), Northern Africa (81.5%) and the Middle East (79.6%). DTP3 coverage decreased in children born to mothers from Europe and former USSR (74.6%), North-east Asia (75.2%), Southern Asia (76.7%), North America (65.5) and South/Central America and the Caribbean (73.2%).ConclusionsOn-time vaccination rates differed by mother’s region of birth. More research is needed to determine the main reasons for these remaining differences to improve vaccine uptake and also help guide policy and practice.     

Pathogenesis of West Nile Virus Lineage 2 in Domestic Geese after Experimental Infection

West Nile virus (WNV) is an emerging infectious pathogen circulating between mosquitoes and birds but also infecting mammals. WNV has become autochthonous in Germany, causing striking mortality rates in avifauna and occasional diseases in humans and horses. We therefore wanted to assess the possible role of free-ranging poultry in the WNV transmission cycle and infected 15 goslings with WNV lineage 2 (German isolate). The geese were monitored daily and sampled regularly to determine viremia, viral shedding, and antibody development by molecular and serological methods. Geese were euthanized at various time points post-infection (pi). All infected geese developed variable degrees of viremia from day 1 to day 10 (maximum) and actively shed virus from days 2 to 7 post-infection. Depending on the time of death, the WN viral genome was detected in all examined tissue samples in at least one individual by RT-qPCR and viable virus was even re-isolated, except for in the liver. Pathomorphological lesions as well as immunohistochemically detectable viral antigens were found mainly in the brain. Furthermore, all of the geese seroconverted 6 days pi at the latest. In conclusion, geese are presumably not functioning as important amplifying hosts but are suitable sentinel animals for WNV surveillance.     

Gradual domestication of root traits in the earliest maize from Tehuacán

Efforts to understand the phenotypic transition that gave rise to maize from teosinte have mainly focused on the analysis of aerial organs, with little insights into possible domestication traits affecting the root system. Archeological excavations in San Marcos cave (Tehuacán, Mexico) yielded two well-preserved 5,300 to 4,970 calibrated y B.P. specimens (SM3 and SM11) corresponding to root stalks composed of at least five nodes with multiple nodal roots and, in case, a complete embryonic root system. To characterize in detail their architecture and anatomy, we used laser ablation tomography to reconstruct a three-dimensional segment of their nodal roots and a scutellar node, revealing exquisite preservation of the inner tissue and cell organization and providing reliable morphometric parameters for cellular characteristics of the stele and cortex. Whereas SM3 showed multiple cortical sclerenchyma typical of extant maize, the scutellar node of the SM11 embryonic root system completely lacked seminal roots, an attribute found in extant teosinte and in two specific maize mutants: root with undetectable meristem1 (rum1) and rootless concerning crown and seminal roots (rtcs). Ancient DNA sequences of SM10—a third San Marcos specimen of equivalent age to SM3 and SM11—revealed the presence of mutations in the transcribed sequence of both genes, offering the possibility for some of these mutations to be involved in the lack of seminal roots of the ancient specimens. Our results indicate that the root system of the earliest maize from Tehuacán resembled teosinte in traits important for maize drought adaptation.

Genetic evidence indicates that maize (Zea mays ssp. mays) populations arose from Balsas teosinte (Zea mays ssp. parviglumis, also named teosinte parviglumis) close to 9,000 y ago (1). This evolutionary transition caused important phenotypic changes in the aerial portion of the plant, including the partial suppression of lateral branching, a decrease in the number of male and female inflorescences per individual, the exposure of the kernel by absence of a cupulate fruitcase, and the transformation of a distichous female inflorescence that disarticulates naturally into a polystichous (3- to 12-ranked) cob with attached grains that require human intervention for dispersal (1–3). A close association has been established between some of these traits and the genes that underlie their developmental control (4, 5), or genomic regions that have lost genetic diversity as a consequence of progressive domestication (6–8). In some cases, paleogenomic analysis of millenary specimens dating to the earliest stages of Mesoamerican cultivation has allowed the establishment of reference time frame for the progression of their genetic diversity and stages of domestication (9–11).By contrast, and despite their importance for supplying water and nutrients during all stages of growth and development, the influence of domestication on the evolution of root architecture and anatomy has received little attention. A phenotypic analysis and comparison of maize landraces and teosintes concluded that their range of root architectural and anatomical traits was similar, however, a few specific traits permitted some distinction between both subspecies (12). In general, teosintes showed less variation for architectural traits such as root system dry weight, longest nodal root length, nodal system diameter, number of root tips, and number of seminal roots. They also showed smaller mean stele and xylem areas, shorter nodal roots, less frequent lateral root branching, and significantly fewer seminal roots than landraces (12), suggesting they could be important traits affected during domestication. Comparisons of physiological responses to limited nitrogen availability indicates that teosinte parviglumis shows an increase of the shoot:root biomass ratio as compared to maize, as well as an increase in the length of nodal and lateral roots, but also reduced nodal root number (13). A functional decrease in major domestication genes such as Teosinte Branched1 (Tb1) results in an increase of both lateral and nodal roots, although it remains unclear if the effect is direct or indirect (14).Root architecture is crucial for productivity by determining the temporal and spatial distribution of soil exploration and hence resource capture. Maize root architecture is comprised of embryonic and postembryonic components (15). After seed germination, the emergence of the radicle and the coleoptile is followed by the elongation of the mesocotyl. While the primary root develops from the radicle, the scutellar node gives rise to seminal roots located in a protuberance formed by the remnants of the pericarp and endosperm, located between the mesocotyl and the primary root. Seminal and primary roots are considered components of the embryonic root system. The first node forms the first nodal roots between the mesocotyl and the coleoptile. Subsequent elongation of the main vertical axis of the mesocotyl results in additional subterranean and root nodes (SI Appendix, Fig. S1). Aerial nodes will give rise to whorls of brace roots.The anatomy of a root transversal section is characterized by the presence of two concentric cellular cylinders: the stele and the cortex. In maize, the central region of the differentiated stele contains xylem vessels responsible for axial transport of water and nutrients. At the periphery of each late metaxylem bundle are the smaller early metaxylem bundles. Phloem vessels, necessary for photosynthate transport, are composed of smaller cells located between late metaxylem bundles. The intersection of the cortex and the stele is composed of two concentric cell files: the pericycle and the endodermis. The cortex is composed of the root epidermis and 6 to 19 files of outer, mid, and inner cortical cells (16, 17). Cortical aerenchyma can be formed via programmed cell death. In some cases, the outer cortex exhibits multiseriate cortical sclerenchyma (MCS) with thick lignified walls, a phenotype recently reported to improve root penetration ability as an adaptation to growth in hard soils (18). Interestingly, the MCS phenotype is present in some modern maize inbreds but not in accessions of teosinte parviglumis and Z. mays ssp. mexicana [teosinte mexicana; (18)], suggesting it might represent an adaptation acquired during domestication.Two maize genes have been shown to be important for development of seminal roots during the establishment of the embryonic root system. Mutations in ROOT WITH UNDETECTABLE MERISTEM1 (RUM1) result in the absence of seminal and postembryonic lateral roots on the primary root (19–21). RUM1 encodes a monocot specific AUX/IAA protein that can be induced by auxin. Similarly, mutants defective in ROOTLESS CONCERNING CROWN AND SEMINAL ROOTS (RTCS) completely lack seminal roots and the postembryonic shoot-borne root system (21). RTCS encodes a Lateral Organ Boundaries (LOB) domain protein preferentially expressed in roots. Two major quantitative loci contributing to 66% of seminal root number variation comapped with RUM1 and RTCS, suggesting both genes play key regulatory functions in the development of the embryonic root system (22).Pioneering excavations conducted in rock shelters of the Tehuacán Valley uncovered maize paleobotanical specimens dating back to the earliest stages of agriculture in Mesoamerica (23, 24), including hundreds of cob specimens, but only a few root crowns. Subsequent explorations of San Marcos cave yielded new nonmanipulated specimens dating to a similar age of 5,300 to 4,970 calibrated y B.P., including SM3, a well-preserved root crown that represents the earliest maize root specimen found to date (10). A paleogenomic analysis of SM3 and other specimens of equivalent age showed that the earliest maize from San Marcos genetically diverged from fully domesticated landraces and contained allelic variants absent from extant maize populations (10). Some domestication loci (teosinte branched1, brittle endosperm2) showed reduced nucleotide variability as compared to teosinte parviglumis, but others (teosinte glume architecture1, sugary1) showed conserved levels of nucleotide variability that are absent from extant maize. These temporally similar samples also showed unexpected levels of homozygosity and inbreeding, opening the possibility for Tehuacán maize cultivation evolving from reduced founder populations (10).To characterize in detail the architecture and anatomy of the earliest maize roots found to date, we conducted laser ablation tomography (LAT) of two paleobotanic specimens (SM3 and SM11) from San Marcos cave, dating at a similar age of 5,280 to 4,956 y B.P. We generated a three-dimensional (3D) reconstruction of a second node root segment for both specimens, confirming the exquisite preservation of their inner cellular organization, and comparing multiple anatomical parameters to extant maize and teosinte accessions. SM3 exhibited MCS proposed to be exclusive to domesticated maize. By contrast, the 3D reconstruction of the scutellar node of SM11 demonstrated the absence of seminal roots, a trait only reported in extant teosintes and two specific maize mutants. Partial sequencing of RUM1 and RTCS alleles present in the genome of SM10—a San Marcos specimen of equivalent age to SM3 and SM11—revealed mutations that could relate to the absence of seminal roots. Our overall results indicate that some of the most important root traits that distinguish extant maize landraces from teosinte were not fully present in the earliest maize from San Marcos.     

Spatial expression of IKK-alpha is associated with a differential mutational landscape and survival in primary colorectal cancer

Background To understand the relationship between key non-canonical NF-κB kinase IKK-alpha(α), tumour mutational profile and survival in primary colorectal cancer.Methods Immunohistochemical expression of IKKα was assessed in a cohort of 1030 patients who had undergone surgery for colorectal cancer using immunohistochemistry. Mutational tumour profile was examined using a customised gene panel. Immunofluorescence was used to identify the cellular location of punctate IKKα expression.Results Two patterns of IKKα expression were observed; firstly, in the tumour cell cytoplasm and secondly as discrete ‘punctate’ areas in a juxtanuclear position. Although cytoplasmic expression of IKKα was not associated with survival, high ‘punctate’ IKKα expression was associated with significantly reduced cancer-specific survival on multivariate analysis. High punctate expression of IKKα was associated with mutations in KRAS and PDGFRA. Dual immunofluorescence suggested punctate IKKα expression was co-located with the Golgi apparatus.Conclusions These results suggest the spatial expression of IKKα is a potential biomarker in colorectal cancer. This is associated with a differential mutational profile highlighting possible distinct signalling roles for IKKα in the context of colorectal cancer as well as potential implications for future treatment strategies using IKKα inhibitors.Subject terms: Prognostic markers, Colorectal cancer     

Family mealtime emotions and food parenting practices among mothers of young children: Development of the Mealtime Emotions Measure for Parents (MEM‐P)

Family mealtimes can be important for supporting children''s healthy development, yet the emotional context of mealtimes can vary considerably, likely impacting their overall success and enjoyment. Yet, despite having an important role, little is known about how parents emotionally experience mealtimes with their family. The first aim of the current study was to assess the factor structure of a novel self‐report measure to assess parents’ emotional responses experienced during family mealtimes (Mealtime Emotions Measure for Parents; MEM‐P). The second aim was to examine relationships between maternal mealtime emotions and their food parenting practices. Mothers of children aged between 1.5 and 6 years participated in this study. Mothers were invited to complete an online questionnaire measuring family mealtime emotions, anxiety, depression and food parenting practices. Exploratory factor analysis produced a three‐factor solution comprising both positive and negative emotion subscales: MEM‐P Efficacy; MEM‐P Anxiety; MEM‐P Stress and Anger. Mothers'' positive mealtime emotions (mealtime efficacy) were related to greater use of practices promoting autonomy, providing a healthy home food environment, and modelling healthy eating. Higher anxiety about mealtimes was related to greater reports of child control over eating, and mealtime stress and anger was associated with greater use of food to regulate emotions. These findings highlight novel relationships between how mothers emotionally experience family mealtimes and the food parenting practices they use with their children. It is important to develop resources to help promote positive maternal experiences of family mealtimes and food‐based interactions.     

Surveillance of γδ T Cells Predicts Cytomegalovirus Infection Resolution in Kidney Transplants

Cytomegalovirus (CMV) infection in solid-organ transplantation is associated with increased morbidity and mortality, particularly if a CMV mutant strain with antiviral resistance emerges. Monitoring CMV–specific T cell response could provide relevant information for patient care. We and others have shown the involvement of Vδ2^neg γδ T cells in controlling CMV infection. Here, we assessed if Vδ2^neg γδ T cell kinetics in peripheral blood predict CMV infection resolution and emergence of a mutant strain in high–risk recipients of kidney transplants, including 168 seronegative recipients receiving organs from seropositive donors (D+R−) and 104 seropositive recipients receiving antithymocyte globulins (R+/ATG). Vδ2^neg γδ T cell percentages were serially determined in patients grafted between 2003 and 2011. The growing phase of Vδ2^neg γδ T cells was monitored in each infected patient, and the expansion rate during this phase was estimated individually by a linear mixed model. A Vδ2^neg γδ T cell expansion rate of ˃0.06% per day predicted the growing phase. The time after infection at which an expansion rate of 0.06% per day occurred was correlated with the resolution of CMV DNAemia (r=0.91; P<0.001). At 49 days of antiviral treatment, Vδ2^neg γδ T cell expansion onset was associated with recovery, whereas absence of expansion was associated with recurrent disease and DNAemia. The appearance of antiviral–resistant mutant CMV strains was associated with delayed Vδ2^neg γδ T cell expansion (P<0.001). In conclusion, longitudinal surveillance of Vδ2^neg γδ T cells in recipients of kidney transplants may predict CMV infection resolution and antiviral drug resistance.     

Supratentorial CAPNON associated with WHO grade II meningioma: A case report

Calcifying pseudoneoplasm of the neuraxis (CAPNON) is a rare benign tumor of uncertain etiology, arising in the craniospinal axis. CAPNON typically arises in isolation, with only two prior reports of a concurrent second neoplasm. Here, we report the case of a male 17‐year‐old who presented with new‐onset seizures. MRIs revealed a 2 cm extra‐axial solid‐cystic mass, arising at the left temporo‐occipital junction and abutting the dura with marked surrounding parenchymal vasogenic edema. The solid components demonstrated dense calcification and avid enhancement. Gross total surgical resection was performed. Histopathological examination revealed central regions showing characteristic features of CAPNON. Toward the periphery, the CAPNON was intimately associated with and sharply demarcated from a meningioma, which showed up to five mitoses per 10 high‐power fields and had invasion into the adjacent brain parenchyma, warranting a WHO grade II designation. This is the first report of CAPNON arising in association with a meningioma. The coexistence of these two tumors raises the possibility of a reactive/dysplastic etiology for CAPNON.