Skip Navigation
Johns Hopkins Bloomberg School of Public HealthCAAT
 

CAAT Grants Program

Research Grants 2018-2019:

Summaries

  • Dania Movia,Trinity College Dublin, Ireland
    Pre-clinical models for predicting the toxicity, absorption and bio distribution of inhaled nanomaterials in humans
     
  • Mathieu Vinken, Department of In Vitro Toxicology, Faculty of Medicine and Pharmacy, Brussels, Belgium
    Establishment and in vitro testing of an adverse outcome pathway network of cholestatic liver injury

Abstracts

Dania Movia, Trinity College Dublin, Ireland
Pre-clinical models for predicting the toxicity, absorption and bio distribution of inhaled nanomaterials in humans

Nanotechnology research is driven by the promise of significant improvements in everyday life, as well as by the attendant business opportunities that might arise from this emerging market. Nanomaterials find extensive application, for instance, in the pharmaceutical and medical fields, as they are ideal technological platforms to support drug delivery through multiple administration routes, including inhalation. Concern has been raised, however, on the potential toxicity of inhaled nano-enabled therapies once accumulated in the human respiratory tract. In addition to intentional administration of nano pharmaceuticals, human lungs can also be exposed to non-medical nano materials, for example during their manufacturing, use or disposal (consumer/occupational safety)To date, inhalation toxicity studies have been relying mainly on small animal models (rodents), which however do not mimiv the anatomy of the human respiratory tract. The project proposed in this application is focused on the development of an alternative pre-clinical model that can predict the toxicity, absorption and biodistribution of inhaled nanomaterials in human. The pre-clinical model developed within the project will be complemented by in vitro and in silico experimental data. The integration of two different experimental approaches, namely lab-based and computer-based studies, will support the development of ad-hoc Biologically Based Dose-Response (BBDR) models to understand the nanomaterials toxic potential following accumulation in the human respiratory tract. 
Gold nanoparticles are selected as a subject of the project proposed herein, since they fin applications in all areas, ranging from the pharmaceutical/medical field to Information Technology. In vitro tissue-mimetic models cultured at the Air-Liquid Interface (MucilAir-HG and SmallAir-HF, supplied by Epithelix Sarl) will be used for testing the cytotoxic and irritant responses to a gold nanoparticle with specific physics-chemical properties. Studies will focus on integrated processes, such as be carried out. This will have the aim to contribute to the creation of a 3R's compliant pre-clinical model for testing nanomaterials' irritant/toxic potential. Translocation from the airway lumen to the bloodstream through the lung epithelium will also be studied in vitro. Computer mathematical approaches called Physiologically Based PharmacoKinetic (PBPK) models will be used to simulate the distribution in the human body of the gold nanoparticles following translocation. The PBPK modeling gives a complete description of how a chemical compound is absorbed, distributed and eliminated by the human body and is commonly applied to predict the drugs distribution in patients. Computer-based modeling is an invaluable and cost-effective strategy for supporting the development of alternatives to animal-based inhalation studies, as proposed within this application.


Mathieu Vinken, Department of In Vitro Toxicology, Faculty of Medicine and Pharmacy
Establishment and in vitro testing of an adverse outcome pathway network of cholestatic liver injury

Cholestasis denotes the accumulation of noxious bile saltsin liver or in systemic circulation and can be triggered by a plethora of chemicals. Although of high toxicological relevance, cholestasis still remains largely unexplored in the contextof the adverse outcome pathway (AOP) concept. The long-term objectives of this project proposal therefore are (i) to develop an AOP network mechanistically describing all criticalmolecularinitiating and key events driving chemical-induced cholestasis, and (ii) to establish a testing battery of animal-free assays based on the AOP network to predict cholestatic potential of chemicals. The specific aim of this project proposal is to set up a proof-of-concept studythat may serve as the solid basis toachieve thelong-term objectives. As a starting point, focus will be put on the only presently available individual AOP construct from bile salt export pump inhibition leading to cholestatic liver injury. In a firststep,a literature search will be performed to identify new molecular initiating events,including inhibition of additional transporter proteins, deterioration of the microtubular system, cytokeratin intermediate filament networks, tight junction integrity as well as decreases in plasma membrane fluidity and bile canaliculi dynamics. In parallel, establishedkey events,namely bile accumulation, the induction of oxidative stress and inflammation as well as the activation of specificnuclear receptors, will be confirmed in vivo by analyzing available liver samples of human patients sufferingfrom cholestatic disorders. Simultaneously, these samples will be tested for potentially new key events, such as unfolded protein responses and concomitant endoplasmic reticulumstress,necroptosis,autophagy and particular signalling cascades, which will be subsequentlyincluded in the emerging AOP network and assessed in compliancewith guidelinesissuedby the Organizationfor Economic Cooperation and Development. In a second step, 5 drugs well-known to clinicallyinduce cholestasis and 5 non-cholestatic drugs will be tested in an established in vitro model of cholestatic liver injury, namely a tridimensional primary human hepatocyte spheroid system cultured in the presence of the 5 most prominenthuman bileacids.Most importantly, a number of functionality and/or expression analysis assays will be performed to test the aforementionedmolecular initiating and key events. This will ultimately yield a battery of in vitro tests that can be used to predict in vivo cholestasis-inducing potential of chemicals. This actually constitutes the rationale for the third step of the project proposal,whereby the chemical space of the testcompoundswill be broadened. Thus, 5 cosmetic ingredients, food additives, biocides or industrialchemicals with suspected yet poorly documented cholestatic properties will be tested in the human tridimensional spheroid model of cholestasis relyingon the establishedin vitrotest battery. Overall, this project proposal will provide new insight into the mechanisms underlying cholestasis, while actively replacing animal experimentation.