Efficacy of Filgotinib in Patients with Ulcerative Colitis by Line of Therapy in the Phase 2b/3 SELECTION Trial

BACKGROUND AND AIMS

The efficacy of new therapies for ulcerative colitis [UC] is usually influenced by previous biologic use. These post hoc analyses of SELECTION, a placebo-controlled phase 2b/3 trial in patients with moderately to severely active UC, evaluated the efficacy of filgotinib, an oral Janus 1 kinase preferential inhibitor, with respect to prior biologic failure.

METHODS

The effect of filgotinib 200 mg (FIL200) relative to placebo was compared in biologic-naïve and biologic-failed patient groups, and in further subgroups by number of failed biologics [1 or >1], biologic mechanism of action [MoA] classes [1 or 2] and tumour necrosis factor [TNF] antagonists [1 or >1]. Odds ratios [ORs] for clinical remission at week 10 [induction] and hazard ratios [HRs] for protocol-specific disease worsening [PSDW] from week 11 to week 58 [maintenance] were calculated.

RESULTS

At week 10, FIL200-treated patients were more likely to achieve clinical remission than placebo-treated patients in the biologic-naïve (OR [95% confidence interval, CI]: 1.98 [1.14-3.44]) and biologic-failed (3.91 [1.33-11.48]) groups. During maintenance, FIL200-treated patients had a reduced risk of PSDW in the biologic-naïve (HR [95% CI]: 0.22 [0.11-0.44]) and biologic-failed (0.22 [0.12-0.40]) groups, and in all biologic-failed subgroups (except >1 TNF antagonist failure). The data suggest that the likelihood of PSDW at week 58 increased with increasing numbers of failed biologics.

CONCLUSIONS

FIL200 induced and maintained benefits relative to placebo regardless of previous biologic use; however, the estimated therapeutic benefit was greatest in biologic-naïve patients and patients previously treated with one biologic or biologic MoA class. [ClinicalTrials.gov: NCT02914522].

GLPG1205 for idiopathic pulmonary fibrosis: a phase 2 randomised placebo-controlled trial

BACKGROUND

GLPG1205 is a selective functional antagonist of G-protein-coupled receptor 84, which plays an important role in fibrotic processes. This study assessed the efficacy, safety and tolerability of GLPG1205 for treatment of idiopathic pulmonary fibrosis (IPF).

METHODS

PINTA (ClinicalTrials.gov: NCT03725852) was a phase 2, randomised, double-blind, placebo-controlled, proof-of-concept trial. Patients with IPF were randomised 2:1 to once-daily oral GLPG1205 100 mg or placebo for 26 weeks and stratified to receive GLPG1205 alone or with local standard of care (nintedanib or pirfenidone). The primary end-point was change from baseline in forced vital capacity (FVC); other end-points were safety and tolerability, and lung volumes measured by imaging (high-resolution computed tomography). The study was not powered for statistical significance.

RESULTS

In total, 68 patients received study medication. Least squares mean change from baseline in FVC at week 26 was -33.68 (95% CI -112.0-44.68) mL with GLPG1205 and -76.00 (95% CI -170.7-18.71) mL with placebo (least squares mean difference 42.33 (95% CI -81.84-166.5) mL; p=0.50). Lung volumes by imaging declined -58.30 versus -262.72 mL (whole lung) and -33.68 versus -135.48 mL (lower lobes) with GLPG1205 versus placebo, respectively. Treatment with GLPG1205 versus placebo resulted in higher proportions of serious and severe treatment-emergent adverse events and treatment-emergent discontinuations, most apparent with nintedanib.

CONCLUSIONS

Treatment with GLPG1205 did not result in a significant difference in FVC decline versus placebo. GLPG1205 demonstrated a poorer safety and tolerability profile than placebo.

Modelling the early phase of the Belgian COVID-19 epidemic using a stochastic compartmental model and studying its implied future trajectories

Following the onset of the ongoing COVID-19 pandemic throughout the world, a large fraction of the global population is or has been under strict measures of physical distancing and quarantine, with many countries being in partial or full lockdown. These measures are imposed in order to reduce the spread of the disease and to lift the pressure on healthcare systems. Estimating the impact of such interventions as well as monitoring the gradual relaxing of these stringent measures is quintessential to understand how resurgence of the COVID-19 epidemic can be controlled for in the future. In this paper we use a stochastic age-structured discrete time compartmental model to describe the transmission of COVID-19 in Belgium. Our model explicitly accounts for age-structure by integrating data on social contacts to (i) assess the impact of the lockdown as implemented on March 13, 2020 on the number of new hospitalizations in Belgium; (ii) conduct a scenario analysis estimating the impact of possible exit strategies on potential future COVID-19 waves. More specifically, the aforementioned model is fitted to hospital admission data, data on the daily number of COVID-19 deaths and serial serological survey data informing the (sero)prevalence of the disease in the population while relying on a Bayesian MCMC approach. Our age-structured stochastic model describes the observed outbreak data well, both in terms of hospitalizations as well as COVID-19 related deaths in the Belgian population. Despite an extensive exploration of various projections for the future course of the epidemic, based on the impact of adherence to measures of physical distancing and a potential increase in contacts as a result of the relaxation of the stringent lockdown measures, a lot of uncertainty remains about the evolution of the epidemic in the next months.

GLPG1205, a GPR84 Modulator: Safety, Pharmacokinetics, and Pharmacodynamics in Healthy Subjects

GLPG1205 is a modulator of GPR84, a G‐protein–coupled receptor reported to be associated with several diseases. Safety, tolerability, pharmacokinetics, and pharmacodynamics of GLPG1205 in healthy subjects were evaluated in 2 randomized, double‐blind, placebo‐controlled, single‐site, phase 1 studies. In study 1, 16 (aged 21‐48 years) and 24 (24‐50 years) healthy men received single doses of GLPG1205 10 to 800 mg, and GLPG1205 50, 100, or 200 mg once daily for 14 days, respectively, or placebo. Study 2 evaluated the effect of aging on GLPG1205 pharmacokinetics: 24 healthy men (aged 37–83 years), weight‐matched into 3 age cohorts (65‐74, ≥75, and 18‐50 years), received GLPG1205 50 mg or placebo once daily for 14 days; an open‐label part of this study evaluated a GLPG1205 250‐mg loading dose followed by 50 mg once daily for 13 days in 8 healthy men (aged 68‐74 years). Single (up to 800 mg) and multiple (maximum tolerated dose 100 mg once daily) GLPG1205 doses had favorable safety and tolerability profiles. After single administration of GLPG1205, median time to occurrence of maximum observed plasma concentration and arithmetic mean apparent terminal half‐life ranged from 2.0 to 4.0 and from 30.1 to 140 hours, respectively. Age did not affect GLPG1205 exposure. GPR84 receptor occupancy with GLPG1205 vs placebo confirmed target engagement. These results support further clinical development of GLPG1205.

Modelling Forced Vital Capacity in Idiopathic Pulmonary Fibrosis: Optimising Trial Design

Introduction

Forced vital capacity is the only registrational endpoint in idiopathic pulmonary fibrosis clinical trials. As most new treatments will be administered on top of standard of care, estimating treatment response will become more challenging. We developed a simulation model to quantify variability associated with forced vital capacity decline.

Methods

The model is based on publicly available clinical trial summary and home spirometry data. A single, illustrative trial setting is reported. Model assumptions are 400 subjects randomised 1:1 to investigational drug or placebo over 52 weeks, 50% of each group receiving standard of care (all-comer population), and a 90-mL treatment difference in annual forced vital capacity decline. Longitudinal profiles were simulated and the impact of varying clinical scenarios evaluated.

Results

Power to detect a significant treatment difference was 87–97%, depending on the analysis method. Repeated measures analysis generally outperformed analysis of covariance and mixed linear models, particularly with missing data (as simulated data were non-linear). A 15% yearly random dropout rate led to 0.6–5% power loss. Forced vital capacity decline-related dropout introduced greater power loss (up to 12%), as did subjects starting/stopping standard of care or investigational drug. Power was substantially lower for a 26-week trial due to the smaller assumed treatment effect at week 26 (sample size would need doubling to reach a power similar to that of a 52-week trial).

Conclusions

Our model quantifies forced vital capacity decline and associated variability, with all the caveats of background therapy, permitting robust power calculations to inform future idiopathic pulmonary fibrosis clinical trial design.

Funding

Galapagos NV (Mechelen, Belgium).

Electronic supplementary material

The online version of this article (10.1007/s12325-019-01093-3) contains supplementary material, which is available to authorized users.

Household members do not contact each other at random: implications for infectious disease modelling

Airborne infectious diseases such as influenza are primarily transmitted from human to human by means of social contacts, and thus easily spread within households. Epidemic models, used to gain insight into infectious disease spread and control, typically rely on the assumption of random mixing within households. Until now, there has been no direct empirical evidence to support this assumption. Here, we present the first social contact survey specifically designed to study contact networks within households. The survey was conducted in Belgium (Flanders and Brussels) from 2010 to 2011. We analysed data from 318 households totalling 1266 individuals with household sizes ranging from two to seven members. Exponential-family random graph models (ERGMs) were fitted to the within-household contact networks to reveal the processes driving contact between household members, both on weekdays and weekends. The ERGMs showed a high degree of clustering and, specifically on weekdays, decreasing connectedness with increasing household size. Furthermore, we found that the odds of a contact between older siblings and between father and child are smaller than for any other pair. The epidemic simulation results suggest that within-household contact density is the main driver of differences in epidemic spread between complete and empirical-based household contact networks. The homogeneous mixing assumption may therefore be an adequate characterization of the within-household contact structure for the purpose of epidemic simulations. However, ignoring the contact density when inferring based on an epidemic model will result in biased estimates of within-household transmission rates. Further research regarding the implementation of within-household contact networks in epidemic models is necessary.

Overcoming the challenges of iris scanning to identify minors (1-4 years) in the real-world setting

Objective

Biometric identification techniques for pediatric use are limited. This investigation studied iris scanning in minors aged 1–4 in two exploratory studies in Belgium (n = 197) and Sierra Leone (n = 230), and in a subsequent clinical study in Sierra Leone (n = 635). Images of participants’ irises were captured using a camera, while a survey assessed the ease of use with children.

Results

The image capture success rate per individual was high; 86.0% of the participants had ≥ 2 successful captures. Iris scan quality and surface were similar in all age groups and in the matching population database. When including feasibility in the analysis of minors aged 3–4, sensitivity and specificity were non-inferior compared to using the biometric of a guardian. However, the quality of iris scanning in minors aged 1–4 was worse than the iris scanning reference quality in adults. A mean total usability score of 1.55 ± 0.27 was calculated; a usability threshold of 1.45 is required for routine use. Overall, this technique is feasible in minors aged 3–4, replacing the use of guardian biometrics. Additional work is ongoing to improve this technique further, striving for uniformity from the age of 1.

Electronic supplementary material

The online version of this article (10.1186/s13104-019-4485-8) contains supplementary material, which is available to authorized users.

Abundant expression of TIM-3, LAG-3, PD-1 and PD-L1 as immunotherapy checkpoint targets in effusions of mesothelioma patients

Malignant pleural mesothelioma (MPM) is an aggressive cancer with an increasing incidence, poor prognosis and limited effective treatment options. Hence, new treatment strategies are warranted which include immune checkpoint blockade approaches with encouraging preliminary data. Research on the immunological aspects of the easily accessible mesothelioma microenvironment could identify prognostic and/or predictive biomarkers and provide useful insights for developing effective immunotherapy. In this context, we investigated the immune cell composition of effusions (pleural and ascites fluids) from 11 different chemotherapy-treated MPM patients. We used multicolor flow cytometry to describe different subsets of immune cells and their expression of immune checkpoint molecules TIM-3, LAG-3, PD-1 and PD-L1. We demonstrate a patient-dependent inter- and intraspecific variation comparing pleural and ascites fluids in immune cell composition and immune checkpoint expression. We found CD4⁺ and CD8⁺ T cells, B cells, macrophages, natural killer cells, dendritic cells and tumor cells in the fluids. To the best of our knowledge, we are the first to report TIM-3 and LAG-3 expression and we confirm PD-1 and PD-L1 expression on different MPM effusion-resident immune cells. Moreover, we identified two MPM effusion-related factors with clinical value: CD4+ T cells were significantly correlated with better response to chemotherapy, while the percentage of PD-L1⁺ podoplanin (PDPN)⁺ tumor cells is a significant prognostic factor for worse outcome. Our data provide a basis for more elaborate research on MPM effusion material in the context of treatment follow-up and prognostic biomarkers and the development of immune checkpoint-targeted immunotherapy.

Structural differences in mixing behavior informing the role of asymptomatic infection and testing symptom heritability

Most infectious disease data is obtained from disease surveillance which is based on observations of symptomatic cases only. However, many infectious diseases are transmitted before the onset of symptoms or without developing symptoms at all throughout the entire disease course, referred to as asymptomatic transmission. Fraser and colleagues [1] showed that this type of transmission plays a key role in assessing the feasibility of intervention measures in controlling an epidemic outbreak. To account for asymptomatic transmission in epidemic models, methods often rely on assumptions that cannot be verified given the data at hand. The present study aims at assessing the contribution of social contact data from asymptomatic and symptomatic individuals in quantifying the contribution of (a)symptomatic infections. We use a mathematical model based on ordinary differential equations (ODE) and a likelihood-based approach followed by Markov Chain Monte Carlo (MCMC) to estimate the model parameters and their uncertainty. Incidence data on influenza-like illness in the initial phase of the 2009 A/H1N1pdm epidemic is used to illustrate that it is possible to estimate either the proportion of asymptomatic infections or the relative infectiousness of symptomatic versus asymptomatic infectives. Further, we introduce a model in which the chance of developing symptoms depends on the disease state of the person that transmitted the infection. In conclusion, incorporating social contact data from both asymptomatic and symptomatic individuals allows inferring on parameters associated with asymptomatic infection based on disease data from symptomatic cases only.

Prognostic and predictive aspects of the tumor immune microenvironment and immune checkpoints in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive cancer with a poor prognosis and an increasing incidence, for which novel therapeutic strategies are urgently required. Since the immune system has been described to play a presumed role in the protection against MPM, characterization of its tumor immune microenvironment (TME) and immune checkpoints can identify new immunotherapeutic targets and their predictive and/or prognostic value. To characterize the TME and the immune checkpoint expression profile, we performed immunohistochemistry (IHC) on formalin-fixed paraffin embedded (FFPE) tissue sections from 54 MPM patients (40 at time of diagnosis; 14 treated with chemotherapy). We stained for PD-1, PD-L1, TIM-3, LAG-3, CD4, CD8, CD45RO, granzyme B, FoxP3 and CD68. Furthermore, we analyzed the relationship between the immunological parameters and survival, as well as response to chemotherapy. We found that TIM-3, PD-1 and PD-L1 were expressed on both immune and tumor cells. Strikingly, PD-1 and PD-L1 expression on tumor cells was only seen in unpretreated samples. No LAG-3 expression was observed. CD45RO expression in the stroma was an independent negative predictive factor for response on chemotherapy, while CD4 and TIM-3 expression in lymphoid aggregates were independent prognostic factors for better outcome. Our data propose TIM-3 as a promising new target in mesothelioma. Chemotherapy influences the expression of immune checkpoints and therefore further research on the best combination treatment schedule is required.

Intracerebral transplantation of interleukin 13-producing mesenchymal stem cells limits microgliosis, oligodendrocyte loss and demyelination in the cuprizone mouse model

Background

Promoting the neuroprotective and repair-inducing effector functions of microglia and macrophages, by means of M2 polarisation or alternative activation, is expected to become a new therapeutic approach for central nervous system (CNS) disorders in which detrimental pro-inflammatory microglia and/or macrophages display a major contribution to the neuropathology. In this study, we present a novel in vivo approach using intracerebral grafting of mesenchymal stem cells (MSC) genetically engineered to secrete interleukin 13 (IL13-MSC).

Methods

In the first experimental setup, control MSC and IL13-MSC were grafted in the CNS of eGFP⁺ bone marrow chimaeric C57BL/6 mice to histologically evaluate IL13-mediated expression of several markers associated with alternative activation, including arginase1 and Ym1, on MSC graft-recognising microglia and MSC graft-infiltrating macrophages. In the second experimental setup, IL13-MSC were grafted on the right side (or on both the right and left sides) of the splenium of the corpus callosum in wild-type C57BL/6 mice and in C57BL/6 CX₃CR1^eGFP/+CCR2^RFP/+ transgenic mice. Next, CNS inflammation and demyelination was induced by means of a cuprizone-supplemented diet. The influence of IL13-MSC grafting on neuropathological alterations was monitored by non-invasive T₂-weighted magnetic resonance imaging (MRI) and quantitative histological analyses, as compared to cuprizone-treated mice with control MSC grafts and/or cuprizone-treated mice without MSC injection.

Results

In the first part of this study, we demonstrate that MSC graft-associated microglia and MSC graft-infiltrating macrophages are forced into alternative activation upon grafting of IL13-MSC, but not upon grafting of control MSC. In the second part of this study, we demonstrate that grafting of IL13-MSC, in addition to the recruitment of M2 polarised macrophages, limits cuprizone-induced microgliosis, oligodendrocyte death and demyelination. Furthermore, we here demonstrate that injection of IL13-MSC at both sides of the splenium leads to a superior protective effect as compared to a single injection at one side of the splenium.

Conclusions

Controlled and localised production of IL13 by means of intracerebral MSC grafting has the potential to modulate cell graft- and pathology-associated microglial/macrophage responses, and to interfere with oligodendrocyte death and demyelinating events in the cuprizone mouse model.

Interleukin-13 immune gene therapy prevents CNS inflammation and demyelination via alternative activation of microglia and macrophages

Detrimental inflammatory responses in the central nervous system are a hallmark of various brain injuries and diseases. With this study we provide evidence that lentiviral vector-mediated expression of the immune-modulating cytokine interleukin 13 (IL-13) induces an alternative activation program in both microglia and macrophages conferring protection against severe oligodendrocyte loss and demyelination in the cuprizone mouse model for multiple sclerosis (MS). First, IL-13 mediated modulation of cuprizone induced lesions was monitored using T₂ -weighted magnetic resonance imaging and magnetization transfer imaging, and further correlated with quantitative histological analyses for inflammatory cell influx, oligodendrocyte death, and demyelination. Second, following IL-13 immune gene therapy in cuprizone-treated eGFP⁺ bone marrow chimeric mice, we provide evidence that IL-13 directs the polarization of both brain-resident microglia and infiltrating macrophages towards an alternatively activated phenotype, thereby promoting the conversion of a pro-inflammatory environment toward an anti-inflammatory environment, as further evidenced by gene expression analyses. Finally, we show that IL-13 immune gene therapy is also able to limit lesion severity in a pre-existing inflammatory environment. In conclusion, these results highlight the potential of IL-13 to modulate microglia/macrophage responses and to improve disease outcome in a mouse model for MS. GLIA 2016;64:2181-2200.

Spatiotemporal Evolution of Ebola Virus Disease at Sub-National Level during the 2014 West Africa Epidemic: Model Scrutiny and Data Meagreness

BACKGROUND

The Ebola outbreak in West Africa has infected at least 27,443 individuals and killed 11,207, based on data until 24 June, 2015, released by the World Health Organization (WHO). This outbreak has been characterised by extensive geographic spread across the affected countries Guinea, Liberia and Sierra Leone, and by localized hotspots within these countries. The rapid recognition and quantitative assessment of localised areas of higher transmission can inform the optimal deployment of public health resources.

METHODS

A variety of mathematical models have been used to estimate the evolution of this epidemic, and some have pointed out the importance of the spatial heterogeneity apparent from incidence maps. However, little is known about the district-level transmission. Given that many response decisions are taken at sub-national level, the current study aimed to investigate the spatial heterogeneity by using a different modelling framework, built on publicly available data at district level. Furthermore, we assessed whether this model could quantify the effect of intervention measures and provide predictions at a local level to guide public health action. We used a two-stage modelling approach: a) a flexible spatiotemporal growth model across all affected districts and b) a deterministic SEIR compartmental model per district whenever deemed appropriate.

FINDINGS

Our estimates show substantial differences in the evolution of the outbreak in the various regions of Guinea, Liberia and Sierra Leone, illustrating the importance of monitoring the outbreak at district level. We also provide an estimate of the time-dependent district-specific effective reproduction number, as a quantitative measure to compare transmission between different districts and give input for informed decisions on control measures and resource allocation. Prediction and assessing the impact of control measures proved to be difficult without more accurate data. In conclusion, this study provides us a useful tool at district level for public health, and illustrates the importance of collecting and sharing data.

Early Inflammatory Responses following Cell Grafting in the CNS Trigger Activation of the Subventricular Zone: A Proposed Model of Sequential Cellular Events

While multiple rodent preclinical studies, and to a lesser extent human clinical trials, claim the feasibility, safety, and potential clinical benefit of cell grafting in the central nervous system (CNS), currently only little convincing knowledge exists regarding the actual fate of the grafted cells and their effect on the surrounding environment (or vice versa). Our preceding studies already indicated that only a minor fraction of the initially grafted cell population survives the grafting process, while the surviving cell population becomes invaded by highly activated microglia/macrophages and surrounded by reactive astrogliosis. In the current study, we further elaborate on early cellular and inflammatory events following syngeneic grafting of eGFP mouse embryonic fibroblasts (mEFs) in the CNS of immunocompetent mice. Based on obtained quantitative histological data, we here propose a detailed mathematically derived working model that sequentially comprises hypoxia-induced apoptosis of grafted mEFs, neutrophil invasion, neoangiogenesis, microglia/macrophage recruitment, astrogliosis, and eventually survival of a limited number of grafted mEFs. Simultaneously, we observed that the cellular events following mEF grafting activates the subventricular zone neural stem and progenitor cell compartment. This proposed model therefore further contributes to our understanding of cell graft-induced cellular responses and will eventually allow for successful manipulation of this intervention.

Cuprizone-induced demyelination and demyelination-associated inflammation result in different proton magnetic resonance metabolite spectra

Conventional MRI is frequently used during the diagnosis of multiple sclerosis but provides only little additional pathological information. Proton MRS ((1) H-MRS), however, provides biochemical information on the lesion pathology by visualization of a spectrum of metabolites. In this study we aimed to better understand the changes in metabolite concentrations following demyelination of the white matter. Therefore, we used the cuprizone model, a well-established mouse model to mimic type III human multiple sclerosis demyelinating lesions. First, we identified CX3 CL1/CX3 CR1 signaling as a major regulator of microglial activity in the cuprizone mouse model. Compared with control groups (heterozygous CX3 CR1(+/-) C57BL/6 mice and wild type CX3 CR1(+/+) C57BL/6 mice), microgliosis, astrogliosis, oligodendrocyte cell death and demyelination were shown to be highly reduced or absent in CX3 CR1(-/-) C57BL/6 mice. Second, we show that (1) H-MRS metabolite spectra are different when comparing cuprizone-treated CX3 CR1(-/-) mice showing mild demyelination with cuprizone-treated CX3 CR1(+/+) mice showing severe demyelination and demyelination-associated inflammation. Following cuprizone treatment, CX3 CR1(+/+) mice show a decrease in the Glu, tCho and tNAA concentrations as well as an increased Tau concentration. In contrast, following cuprizone treatment CX3 CR1(-/-) mice only showed a decrease in tCho and tNAA concentrations. Therefore, (1) H-MRS might possibly allow us to discriminate demyelination from demyelination-associated inflammation via changes in Tau and Glu concentration. In addition, the observed decrease in tCho concentration in cuprizone-induced demyelinating lesions should be further explored as a possible diagnostic tool for the early identification of human MS type III lesions.

Distinct In Vitro Properties of Embryonic and Extraembryonic Fibroblast-Like Cells are Reflected in their in Vivo Behavior following Grafting in the Adult Mouse Brain

Although intracerebral transplantation of various fibroblast(-like) cell populations has been shown feasible, little is known about the actual in vivo remodeling of these cellular grafts and their environment. In this study, we aimed to compare the in vitro and in vivo behavior of two phenotypically similar—but developmentally distinct—fibroblast-like cell populations, namely, mouse embryonic fibroblasts (mEFs) and mouse fetal membrane-derived stromal cells (mFMSCs). While both mEFs and mFMSCs are readily able to reduce TNF-α secretion by LPS/IFN-γ-activated BV-2 microglia, mFMSCs and mEFs display strikingly opposite behavior with regard to VEGF production under normal and inflammatory conditions. Whereas mFMSCs downregulate VEGF production upon coculture with LPS/IFN-γ-activated BV-2 microglia, mEFs upregulate VEGF production in the presence of LPS/IFN-γ-activated BV-2 microglia. Subsequently, in vivo grafting of mFMSCs and mEFs revealed no difference in microglial and astroglial responses toward the cellular grafts. However, mFMSC grafts displayed a lower degree of neoangiogenesis compared to mEF grafts, thereby potentially explaining the lower cell number able to survive in mFMSC grafts. In summary, our results suggest that physiological differences between fibroblast-like cell populations might lie at the basis of variations in histopathological and/or clinical outcome following cell grafting in mouse brain.

The social contact hypothesis under the assumption of endemic equilibrium: Elucidating the transmission potential of VZV in Europe

The basic reproduction number R0 and the effective reproduction number R are pivotal parameters in infectious disease epidemiology, quantifying the transmission potential of an infection in a population. We estimate both parameters from 13 pre-vaccination serological data sets on varicella zoster virus (VZV) in 12 European countries and from population-based social contact surveys under the commonly made assumptions of endemic and demographic equilibrium. The fit to the serology is evaluated using the inferred effective reproduction number R as a model eligibility criterion combined with AIC as a model selection criterion. For only 2 out of 12 countries, the common choice of a constant proportionality factor is sufficient to provide a good fit to the seroprevalence data. For the other countries, an age-specific proportionality factor provides a better fit, assuming physical contacts lasting longer than 15 min are a good proxy for potential varicella transmission events. In all countries, primary infection with VZV most often occurs in early childhood, but there is substantial variation in transmission potential with R0 ranging from 2.8 in England and Wales to 7.6 in The Netherlands. Two non-parametric methods, the maximal information coefficient (MIC) and a random forest approach, are used to explain these differences in R0 in terms of relevant country-specific characteristics. Our results suggest an association with three general factors: inequality in wealth, infant vaccination coverage and child care attendance. This illustrates the need to consider fundamental differences between European countries when formulating and parameterizing infectious disease models.

Assessing the risk of measles resurgence in a highly vaccinated population: Belgium anno 2013

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Histological characterization and quantification of cellular events following neural and fibroblast(-like) stem cell grafting in healthy and demyelinated CNS tissue

Preclinical animal studies involving intracerebral (stem) cell grafting are gaining popularity in many laboratories due to the reported beneficial effects of cell grafting on various diseases or traumata of the central nervous system (CNS). In this chapter, we describe a histological workflow to characterize and quantify cellular events following neural and fibroblast(-like) stem cell grafting in healthy and demyelinated CNS tissue. First, we provide standardized protocols to isolate and culture eGFP(+) neural and fibroblast(-like) stem cells from embryonic mouse tissue. Second, we describe flow cytometric procedures to determine cell viability, eGFP transgene expression, and the expression of different stem cell lineage markers. Third, we explain how to induce reproducible demyelination in the CNS of mice by means of cuprizone administration, a validated mouse model for human multiple sclerosis. Fourth, the technical procedures for cell grafting in the CNS are explained in detail. Finally, an optimized and validated workflow for the quantitative histological analysis of cell graft survival and endogenous astroglial and microglial responses is provided.