In vitro models for non-alcoholic fatty liver disease: Emerging platforms and their applications

Non-alcoholic fatty liver disease (NAFLD) represents a global healthcare challenge, affecting 1 in 4 adults, and death rates are predicted to rise inexorably. The progressive form of NAFLD, non-alcoholic steatohepatitis (NASH), can lead to fibrosis, cirrhosis, and hepatocellular carcinoma. However, no medical treatments are licensed for NAFLD-NASH. Identifying efficacious therapies has been hindered by the complexity of disease pathogenesis, a paucity of predictive preclinical models and inadequate validation of pharmacological targets in humans. The development of clinically relevant in vitro models of the disease will pave the way to overcome these challenges. Currently, the combined application of emerging technologies (e.g., organ-on-a-chip/microphysiological systems) and control engineering approaches promises to unravel NAFLD biology and deliver tractable treatment candidates. In this review, we will describe advances in preclinical models for NAFLD-NASH, the recent introduction of novel technologies in this space, and their importance for drug discovery endeavors in the future

Face Coverings and Respiratory Tract Droplet Dispersion

Abstract Respiratory droplets are the primary transmission route for SARS-CoV-2, a principle which drives social distancing guidelines. Evidence suggests that virus transmission can be reduced by face coverings, but robust evidence for how mask usage might affect safe distancing parameters is lacking. Accordingly, we set out to quantify the effects of face coverings on respiratory tract droplet deposition. We tested an anatomically realistic manikin head which ejected fluorescent droplets of water and human volunteers, in speaking and coughing conditions without a face covering, or with a surgical mask or a single-layer cotton face covering. We quantified the number of droplets in flight using laser sheet illumination and UV-light for those that had landed at table height at up to 2 m. For human volunteers, expiratory droplets were caught on a microscope slide 5 cm from the mouth. Whether manikin or human, wearing a face covering decreased the number of projected droplets by less than 1000-fold. We estimated that a person standing 2 m from someone coughing without a mask is exposed to over 10 000 times more respiratory droplets than from someone standing 0.5 m away wearing a basic single-layer mask. Our results indicate that face coverings show consistent efficacy at blocking respiratory droplets and thus provide an opportunity to moderate social distancing policies. However, the methodologies we employed mostly detect larger (non-aerosol) sized droplets. If the aerosol transmission is later determined to be a significant driver of infection, then our findings may overestimate the effectiveness of face coverings

On-line optimal input design increases the efficiency and accuracy of the modelling of an inducible synthetic promoter

Synthetic biology seeks to design biological parts and circuits that implement new functions in cells. Major accomplishments have been reported in this field, yet predicting a priori the in vivo behaviour of synthetic gene circuits is major a challenge. Mathematical models offer a means to address this bottleneck. However, in biology, modelling is perceived as an expensive, time-consuming task. Indeed, the quality of predictions depends on the accuracy of parameters, which are traditionally inferred from poorly informative data. How much can parameter accuracy be improved by using model-based optimal experimental design (MBOED)? To tackle this question, we considered an inducible promoter in the yeast S. cerevisiae. Using in vivo data, we re-fit a dynamic model for this component and then compared the performance of standard (e.g., step inputs) and optimally designed experiments for parameter inference. We found that MBOED improves the quality of model calibration by ∼60%. Results further improve up to 84% when considering on-line optimal experimental design (OED). Our in silico results suggest that MBOED provides a significant advantage in the identification of models of biological parts and should thus be integrated into their characterisation.This research was partially supported by EC funding H2020 FET OPEN 766840-COSY-BIO and a Royal Society of Edinburgh-MoST grant (to F.M.), EPSRC funding EP/P017134/1-CONDSYC (to L.B.) and Spanish MINECO, grant ref. AGL2015-67504-C3-2-R (to E.B.-C.).Peer reviewe

Physiological adaptations affecting drug pharmacokinetics in space: what do we really know? A critical review of the literature

As human spaceflight progresses with extended mission durations, the demand for effective and safe drugs will necessarily increase. To date, the accepted medications used during missions (for space motion sickness, sleep disturbances, allergies, pain, and sinus congestion) are administered under the assumption that they act as safely and efficaciously as on Earth. However, physiological changes have been documented in human subjects in spaceflight involving fluid shifts, muscle and bone loss, immune system dysregulation, and adjustments in the gastrointestinal tract and metabolism. These alterations may change the pharmacokinetics (PK) and pharmacodynamics of commonly used medications. Frustratingly, the information gained from bed rest studies and from in‐flight observations is incomplete and also demonstrates a high variability in drug PK. Therefore, the objectives of this review are to report (i) the impact of the space environmental stressors on human physiology in relation to PK; (ii) the state‐of‐the‐art on experimental data in space and/or in ground‐based models; (iii) the validation of ground‐based models for PK studies; and (iv) the identification of research gaps

Morphological findings in malformed fetuses with normal karyotype

In our Department morphological findings on fetuses from therapeutic interruption of pregnancy or spontaneous abortion are performed since ten years in order to correlate the ultrasound and/or chromosomic diagnosis with a real presence of malformations. The fetopathologic examination generally agrees with the chromosomal diagnosis, while in several cases it is possible to find malformations also in presence of a normal karyotype (Gitz, 2011). In our experience over the past 5 years we have found that 17 fetuses with a normal karyotype showed different heterogeneous ultrasound malformations. Only in 2 cases the fetuses died in uterus (17th and 22nd weeks of gestation), the other cases, aged between 14th and 23rd weeks of gestation, went from voluntary abortions. In 7 cases the karyotype was defined by amniocentesis while in the remaining 10 was determined by fetal fibroblasts culture; in only 30% of the observed cases the couple had carried out a genetic evaluation. External malformations were present in 16 fetuses, often related to the face (such as micrognathia, low-set of ears, flattened nasal bridge, cleft lip) or limb (short, curved, stubby) of spine (spina bifida) or genitalia (hypospadias). Malformations of internal organs were present in 10 cases, often affecting the cardiovascular system (complex heart defects and abnormal origin of the greath vessels), and nervous system (meningocele, agenesia of the corpus callosum, ventricular dilatation and Arnold-Chiari malformation); less frequent were malformations of other systems (digestive, respiratory and urinary). There was a single case of situs viscerum inversus associated with complex cardiac malformations and atresia of the bucco-pharyngeal membrane. These results indicate that the fetal morphological study is useful not only to confirm but often to supplement and complete the ultrasound data. Moreover genetic evaluation, utilizing fetopatholgical study, may have an important role in defining the diagnostic and clinical procedure, especially in relapses with malformed fetus and normal karyotype

Impact of safety-related dose reductions or discontinuations on sustained virologic response in HCV-infected patients: Results from the GUARD-C Cohort

BACKGROUND: Despite the introduction of direct-acting antiviral agents for chronic hepatitis C virus (HCV) infection, peginterferon alfa/ribavirin remains relevant in many resource-constrained settings. The non-randomized GUARD-C cohort investigated baseline predictors of safety-related dose reductions or discontinuations (sr-RD) and their impact on sustained virologic response (SVR) in patients receiving peginterferon alfa/ribavirin in routine practice. METHODS: A total of 3181 HCV-mono-infected treatment-naive patients were assigned to 24 or 48 weeks of peginterferon alfa/ribavirin by their physician. Patients were categorized by time-to-first sr-RD (Week 4/12). Detailed analyses of the impact of sr-RD on SVR24 (HCV RNA <50 IU/mL) were conducted in 951 Caucasian, noncirrhotic genotype (G)1 patients assigned to peginterferon alfa-2a/ribavirin for 48 weeks. The probability of SVR24 was identified by a baseline scoring system (range: 0-9 points) on which scores of 5 to 9 and <5 represent high and low probability of SVR24, respectively. RESULTS: SVR24 rates were 46.1% (754/1634), 77.1% (279/362), 68.0% (514/756), and 51.3% (203/396), respectively, in G1, 2, 3, and 4 patients. Overall, 16.9% and 21.8% patients experienced 651 sr-RD for peginterferon alfa and ribavirin, respectively. Among Caucasian noncirrhotic G1 patients: female sex, lower body mass index, pre-existing cardiovascular/pulmonary disease, and low hematological indices were prognostic factors of sr-RD; SVR24 was lower in patients with 651 vs. no sr-RD by Week 4 (37.9% vs. 54.4%; P = 0.0046) and Week 12 (41.7% vs. 55.3%; P = 0.0016); sr-RD by Week 4/12 significantly reduced SVR24 in patients with scores <5 but not 655. CONCLUSIONS: In conclusion, sr-RD to peginterferon alfa-2a/ribavirin significantly impacts on SVR24 rates in treatment-naive G1 noncirrhotic Caucasian patients. Baseline characteristics can help select patients with a high probability of SVR24 and a low probability of sr-RD with peginterferon alfa-2a/ribavirin

SteatoSITE: an Integrated Gene-to-Outcome Data Commons for Precision Medicine Research in NAFLD

Nonalcoholic fatty liver disease (NAFLD) is the commonest cause of chronic liver disease worldwide and a growing healthcare burden. The pathobiology of NAFLD is complex, disease progression is variable and unpredictable, and there are no qualified prognostic biomarkers or licensed pharmacotherapies that can improve clinical outcomes; it represents an unmet precision medicine challenge. We established a retrospective multicentre national cohort of 940 patients, across the complete NAFLD spectrum, integrating quantitative digital pathology, hepatic RNA-sequencing and 5.67 million days of longitudinal electronic health record follow-up into a secure, searchable, open resource (SteatoSITE) to inform rational biomarker and drug development and facilitate personalised medicine approaches for NAFLD. A complementary web-based gene browser was also developed. Here, our initial analysis uncovers disease stage-specific gene expression signatures, pathogenic hepatic cell subpopulations and master regulator networks associated with disease progression in NAFLD. Additionally, we construct novel transcriptional risk prediction tools for the development of future hepatic decompensation events