PARC Projects

Shift away from animal testing
Biodiversity protection
New approaches to assess organ toxicity without animal testing
NGRA
Human health
Health effects
Time span
-
Potential impacts
  • Delivery of an IATA focusing on liver fibrosis
  • Development of a quantitative AOP for liver fibrosis
  • Demonstration of the practical applicability of the established IATA through case studies
Partners involved
AUTH (GR)
IISPV (ES)
INSERM (FR)
IRFMN (IT)
ISS (IT)
MU (CZ)
STAMI (NO)
UGent (BE)
WR (NL)
WU-TOX (NL)
Contacts
Bob van de Water (UL-LACDR)
b.water [at] lacdr.leidenuniv.nl
Joost Beltman (UL-LACDR)
j.b.beltman [at] lacdr.leidenuniv.nl
Key messages
  • An Integrated Approaches to Testing and Assessment (IATA ↗) for liver fibrosis is in development based on assays that incorporate multiple cell types involved in liver fibrosis.
  • Various liver cell types are investigated for their suitability for liver fibrosis-related Adverse Outcome Pathways (AOPs ↗).
  • Liver fibrosis-related AOPs are being quantified.
Overview

Within PARC, this project aims to deliver Integrated Approaches to Testing and Assessment (IATA) for selected health effects, primarily focusing on human health. These approaches are developed collaboratively with ECHA ↗ and EFSA ↗ and evaluated through dedicated case studies.  

The project prioritises liver toxicity, particularly liver fibrosis, due to its complicated nature with multiple cell types involved and the availability of supporting data from published animal studies. 

To achieve this, the project will implement scientifically advanced in vitro methods, in which multiple cell types that occur in the liver are combined. This will reduce reliance on traditional animal testing.  

Currently, there is no IATA for liver fibrosis. This project aims to fill that gap by providing stakeholders with a scientifically robust, non-animal testing strategy for liver fibrosis, with potential applications in safety testing. Beyond being an essential first step, this approach will contribute to fulfilling regulatory requirements for STOT (Single and Repeated Exposure) classification under REACH ↗. Moreover, it will provide a quantitative assessment of the involved assays, enhancing their relevance to adverse outcomes. 

Achievements & Results

In this project, inventories of existing AOPs related to liver fibrosis, as well as NAMs ↗ relevant to key events (KEs) within these AOPs, were created. New assays incorporating multiple liver cell types involved in fibrosis were developed. In parallel, chemicals known to trigger relevant AOPs — based on existing animal data — were selected.

To determine the most suitable liver cell type for inclusion in the IATA, four liver cell test systems were exposed to the selected chemicals. Data were generated to assess their sensitivity and the resulting gene expression changes. Preliminary analysis indicates that responses from primary hepatocytes are the most representative.

Additionally, a framework for the development of mathematical models describing AOPs was published, and initial steps were taken to apply this framework to existing animal data.

Policy relevance

The successful development of an IATA for liver fibrosis will provide confidence in the assessment of complex in vivo STOT end-points that involve multiple cell types. This confidence building will be essential for policy development for animal-free methods for STOT assessment.

Related Publications

Developing quantitative Adverse Outcome Pathways: An ordinary differential equation-based computational framework
Developing quantitative Adverse Outcome Pathways: An ordinary differential equation-based computational framework copied to clipboard
Authors
Di Tillio Filippo, Beltman Joost
Journal
Computational Toxicology
Vol. 32
100330
Keywords
Ordinary differential equations (ODEs), Quantitative Adverse Outcome Pathway (qAOP), Key event relationships (KERs), Adverse outcome (AO), Response–response modeling, Predictive toxicology, Markov chain Monte Carlo (MCMC), Population variability
Date of publication
copied to clipboard
1/3

Ordinary differential equation (ODE)-based quantitative adverse outcome pathway (qAOP) framework allows for population level adverse outcome prediction.

2/3

The framework provides model selection and updating.

3/3

The framework outperforms response–response modeling.

1/1

The quantitative adverse outcome pathway (qAOP) framework provides data-driven tools to refine chemical safety thresholds, ensuring evidence-based updates to REACH and other EU regulations.

The Adverse Outcome Pathway (AOP) biological framework was introduced in 2012, yet defining a mathematical/computational framework for quantitative AOP (qAOP) development remains an open problem. In order to properly unravel the intricate biological mechanisms described by AOPs and provide quantitative predictions to support risk assessment, a computational model should provide a clear time-course prediction of key events (KEs), as well as describe the key event relationships (KERs) linking a molecular initiating event (MIE) to an adverse outcome (AO). Ultimately, the mathematical description of those links entails the possibility of quantitatively predicting adverse effects based on early events.
 
Here, we propose an ordinary differential equation (ODE) - based qAOP framework, as ODEs provide a time-course description of KEs and KERs. We illustrate how the application of computational techniques, such as Bayesian inference and Leave-one-out cross-validation (LOO-CV), can assist AOP development, introducing concepts of qAOP model selection and qAOP updating. Furthermore, we compare ODE and response–response based qAOP models, showing that ODE-based qAOPs can avoid erroneous predictions potentially resulting from response–response qAOPs. Finally, we show how ODE parameter variability can be linked to AO variability across a population. Overall, this framework serves as a valuable mathematical and computational tool for the development of qAOP models, enhancing our comprehension of intricate biological pathways associated with adverse outcomes.
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Environment
Health effects
Human health
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NGRA
Mixtures
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Workers
Streamlining data processing methods for suspect and non-target screening
Streamlining data processing methods for suspect and non-target screening

New approaches to assess organ toxicity without animal testing

Time span
-
Potential impacts
  • Delivery of an IATA focusing on liver fibrosis
  • Development of a quantitative AOP for liver fibrosis
  • Demonstration of the practical applicability of the established IATA through case studies
AUTH (GR)
IISPV (ES)
INSERM (FR)
IRFMN (IT)
ISS (IT)
MU (CZ)
STAMI (NO)
UGent (BE)
WR (NL)
WU-TOX (NL)
Key messages
  • An Integrated Approaches to Testing and Assessment (IATA ↗) for liver fibrosis is in development based on assays that incorporate multiple cell types involved in liver fibrosis.
  • Various liver cell types are investigated for their suitability for liver fibrosis-related Adverse Outcome Pathways (AOPs ↗).
  • Liver fibrosis-related AOPs are being quantified.
Overview

Within PARC, this project aims to deliver Integrated Approaches to Testing and Assessment (IATA) for selected health effects, primarily focusing on human health. These approaches are developed collaboratively with ECHA ↗ and EFSA ↗ and evaluated through dedicated case studies.  

The project prioritises liver toxicity, particularly liver fibrosis, due to its complicated nature with multiple cell types involved and the availability of supporting data from published animal studies. 

To achieve this, the project will implement scientifically advanced in vitro methods, in which multiple cell types that occur in the liver are combined. This will reduce reliance on traditional animal testing.  

Currently, there is no IATA for liver fibrosis. This project aims to fill that gap by providing stakeholders with a scientifically robust, non-animal testing strategy for liver fibrosis, with potential applications in safety testing. Beyond being an essential first step, this approach will contribute to fulfilling regulatory requirements for STOT (Single and Repeated Exposure) classification under REACH ↗. Moreover, it will provide a quantitative assessment of the involved assays, enhancing their relevance to adverse outcomes. 

Achievements & Results

In this project, inventories of existing AOPs related to liver fibrosis, as well as NAMs ↗ relevant to key events (KEs) within these AOPs, were created. New assays incorporating multiple liver cell types involved in fibrosis were developed. In parallel, chemicals known to trigger relevant AOPs — based on existing animal data — were selected.

To determine the most suitable liver cell type for inclusion in the IATA, four liver cell test systems were exposed to the selected chemicals. Data were generated to assess their sensitivity and the resulting gene expression changes. Preliminary analysis indicates that responses from primary hepatocytes are the most representative.

Additionally, a framework for the development of mathematical models describing AOPs was published, and initial steps were taken to apply this framework to existing animal data.

Policy relevance

The successful development of an IATA for liver fibrosis will provide confidence in the assessment of complex in vivo STOT end-points that involve multiple cell types. This confidence building will be essential for policy development for animal-free methods for STOT assessment.

Contacts
Bob van de Water (UL-LACDR)
b.water [at] lacdr.leidenuniv.nl
Joost Beltman (UL-LACDR)
j.b.beltman [at] lacdr.leidenuniv.nl
Topics
Shift away from animal testing
Biodiversity protection
Keywords
NGRA
Human health
Health effects

Related Projects

Rethinking genotoxicity testing: A non-animal approach
Harmonised workflow for human relevance assessment of Adverse Outcome Pathways (AOPs) and New Approach Methodologies (NAMs)
Advancing endocrine disruptor assessment