Complex In Vitro Model Characterization for Context of Use in Toxicologic Pathology: Use Cases by Collaborative Teams of Biologists, Bioengineers, and Pathologists.

Complex in vitro models (CIVMs) offer the potential to increase the clinical relevance of preclinical efficacy and toxicity assessments and reduce the reliance on animals in drug development. The European Society of Toxicologic Pathology (ESTP) and Society for Toxicologic Pathology (STP) are collaborating to highlight the role of pathologists in the development and use of CIVM. Pathologists are trained in comparative animal medicine which enhances their understanding of mechanisms of human and animal diseases, thus allowing them to bridge between animal models and humans.

Toxicologic Pathology Forum: Opinion on Not Euthanizing Control Animals in the Recovery Phase of Non-Rodent Toxicology Studies.

Nonclinical toxicology studies that are required to support human clinical trials of new drug candidates are generally conducted in a rodent and a non-rodent species. These studies typically contain a vehicle control group and low, intermediate, and high dose test article groups. In addition, a dosing-free recovery phase is sometimes included to determine reversibility of potential toxicities observed during the dosing phase and may include additional animals in the vehicle control and one or more dose groups.

Determination of proton dissociation constants (pK) of hydroxyl groups of 2,5-dihydroxy-1,4-benzoquinone (DHBQ) by UV-Vis, fluorescence and ATR-FTIR spectroscopy.

The dissociation constant is an important physicochemical parameter of amolecule. The protonation state of a molecule reflects its reactivity, solubility or ability to chemically interact with other molecules. In the present study, dissociation constants (pK) values of 2,5-dihydroxy-1,4-benzoquinone (DHBQ) were determined by UV-Vis, fluorescence and ATR-FTIR spectroscopy at 25 °C.

Perspectives on the evaluation and adoption of complex in vitro models in drug development: Workshop with the FDA and the pharmaceutical industry (IQ MPS Affiliate).

Complex in vitro models (CIVM) offer the potential to improve pharmaceutical clinical drug attrition due to safety and/ or efficacy concerns. For this technology to have an impact, the establishment of robust characterization and qualifi­cation plans constructed around specific contexts of use (COU) is required. This article covers the output from a workshop between the Food and Drug Administration (FDA) and Innovation and Quality Microphysiological Systems (IQ MPS) Affiliate.

Opinion on the Use of Animal Models in Nonclinical Safety Assessment: Pros and Cons.

Nonclinical evaluation of human safety risks for new chemical entities (NCEs) is primarily conducted in conventional healthy animals (CHAs); however, in certain instances, animal models of diseases (AMDs) can play a critical role in the understanding of human health risks. Animal models of diseases may be especially important when there is a need to understand how disease conditions associated with the intended indication might impact risk assessment of NCEs or when CHAs lack the human-specific target of interest (receptor, etc). Although AMDs have potential benefits over CHAs, they also have limitations.

Publication Categories in .

is the official journal of the Society of Toxicologic Pathology (STP), the British Society of Toxicological Pathology, and the European STP (ESTP). publishes articles related to topics in various aspects of toxicologic pathology such as anatomic pathology, clinical pathology, experimental pathology, and biomarker research. Publications include society-endorsed Best Practice/Position and Points to Consider publications and ESTP Expert Workshop articles that are relevant to toxicologic pathology and scientific regulatory processes, Opinion articles under the banner of the STP Toxicologic Pathology Forum, Original Articles, Review Articles (unsolicited/contributed, mini, and invited), Brief Communications, Letters to the Editor, Meeting Reports, and Book Reviews.

Cardiovascular microphysiological systems (CVMPS) for safety studies - a pharma perspective.

The integrative responses of the cardiovascular (CV) system are essential for maintaining blood flow to provide oxygenation, nutrients, and waste removal for the entire body. Progress has been made in independently developing simple in vitro models of two primary components of the CV system, namely the heart (using induced pluripotent stem-cell derived cardiomyocytes) and the vasculature (using endothelial cells and smooth muscle cells). These two in vitro biomimics are often described as immature and simplistic, and typically lack the structural complexity of native tissues.

Microphysiological Systems: A Pathologist's Perspective.

High-throughput in vitro models lack human-relevant complexity, which undermines their ability to accurately mimic in vivo biologic and pathologic responses. The emergence of microphysiological systems (MPS) presents an opportunity to revolutionize in vitro modeling for both basic biomedical research and applied drug discovery. The MPS platform has been an area of interdisciplinary collaboration to develop new, predictive, and reliable in vitro methods for regulatory acceptance.

Developing in vitro assays to transform gastrointestinal safety assessment: potential for microphysiological systems.

Drug-induced gastrointestinal toxicities (DI-GITs) are among the most common adverse events in clinical trials. High prevalence of DI-GIT has persisted among new drugs due in part to the lack of robust experimental tools to allow early detection or to guide optimization of safer molecules. Developing in vitro assays for the leading GI toxicities (nausea, vomiting, diarrhoea, constipation, and abdominal pain) will likely involve recapitulating complex physiological properties that require contributions from diverse cell/tissue types including epithelial, immune, microbiome, nerve, and muscle.

A pharmaceutical industry perspective on microphysiological kidney systems for evaluation of safety for new therapies.

The human kidney contains approximately one million nephrons. As the functional unit of the kidney, the nephron affords an opportunity to approximate the kidney at a microphysiological scale. Recent emergence of physiologically accurate human tissue models has radically advanced the possibilities of mimicking organ biology and multi-organ combinations in vitro.

Liver microphysiological systems development guidelines for safety risk assessment in the pharmaceutical industry.

The liver is critical to consider during drug development because of its central role in the handling of xenobiotics, a process which often leads to localized and/or downstream tissue injury. Our ability to predict human clinical safety outcomes with animal testing is limited due to species differences in drug metabolism and disposition, while traditional human in vitro liver models often lack the necessary in vivo physiological fidelity. To address this, increasing numbers of liver microphysiological systems (MPS) are being developed, however the inconsistency in their optimization and characterization often leads to models that do not possess critical levels of baseline performance that is required for many pharmaceutical industry applications.

Drug-induced skin toxicity: gaps in preclinical testing cascade as opportunities for complex in vitro models and assays.

Skin is the largest organ of the body and serves as the principle barrier to the environment. Composed of multiple cell types arranged in stratified layers with highly specialized appendages, it serves sensory and immune surveillance roles in addition to its primary mechanical function. Several complex in vitro models of skin (i.

Evaluation of the safety of a genetically modified DAS-444Ø6-6 soybean meal and hulls in a 90-day dietary toxicity study in rats.

A 90-day sub chronic toxicity study was conducted in rats to evaluate the safety of genetically modified DAS-444Ø6-6 soybeans expressing herbicide tolerant proteins when compared with its conventional comparators (non-transgenic near isoline control soybean and three commercially available non-transgenic line control soybeans). Rats were given diets formulated with either 10% or 20% w/w of soybean meal and 1% or 2% hulls of DAS-444Ø6-6 soybean with an equivalent amount of hulls from an isoline non-transgenic control soybean for at least 90 days. In addition, three separate 20% w/w non-transgenic commercially available soybean varieties were also given to groups of rats to serve as reference controls.

Navigating tissue chips from development to dissemination: A pharmaceutical industry perspective.

Tissue chips are poised to deliver a paradigm shift in drug discovery. By emulating human physiology, these chips have the potential to increase the predictive power of preclinical modeling, which in turn will move the pharmaceutical industry closer to its aspiration of clinically relevant and ultimately animal-free drug discovery. Despite the tremendous science and innovation invested in these tissue chips, significant challenges remain to be addressed to enable their routine adoption into the industrial laboratory.

Dose-response analysis of epigenetic, metabolic, and apical endpoints after short-term exposure to experimental hepatotoxicants.

Identification of sensitive and novel biomarkers or endpoints associated with toxicity and carcinogenesis is of a high priority. There is increasing interest in the incorporation of epigenetic and metabolic biomarkers to complement apical data; however, a number of questions, including the tissue specificity, dose-response patterns, early detection of those endpoints, and the added value need to be addressed. In this study, we investigated the dose-response relationship between apical, epigenetic, and metabolomics endpoints following short-term exposure to experimental hepatotoxicants, clofibrate (CF) and phenobarbital (PB).

Scientific and Regulatory Policy Committee (SRPC) Review: Interpretation and Use of Cell Proliferation Data in Cancer Risk Assessment.

Increased cell proliferation is a central key event in the mode of action for many non-genotoxic carcinogens, and quantitative cell proliferation data play an important role in the cancer risk assessment of many pharmaceutical and environmental compounds. Currently, there is limited unified information on assay standards, reference values, targeted applications, study design issues, and quality control considerations for proliferation data. Here, we review issues in measuring cell proliferation indices, considerations for targeted studies, and applications within current risk assessment frameworks.

A critical assessment of the methodologies to investigate the role of inhibition of apoptosis in rodent hepatocarcinogenesis.

Non-genotoxic carcinogens act by promoting the clonal expansion of preneoplastic cells by directly or indirectly stimulating cell division or inhibiting cell loss in the target organ. The specific mode-of-action (MoA) by which some non-genotoxic carcinogens ultimately cause cancer is not completely understood. To date, there are several proposed MoAs for non-genotoxic carcinogens, and some of these propose inhibition of apoptosis as one of the key events.

Characterization of nuclear receptor-mediated murine hepatocarcinogenesis of the herbicide pronamide and its human relevance.

The key events responsible for mouse liver tumors induced by a pesticide (viz., pronamide) were investigated in a series of studies employing molecular, biochemical, cellular, and apical endpoints. Based on these studies, it was demonstrated that the liver tumors were mediated by a mode of action (MoA) involving nuclear receptors (NRs) through the following key events: (1) CAR and PPAR-α receptor activation, (2) increased hepatocellular proliferation, eventually leading to (3) hepatocellular tumors.

Concurrent evaluation of general, immune, and genetic toxicity endpoints as part of an integrated testing strategy.

Integrated testing strategies involve the assessment of multiple endpoints within a single toxicity study and represent an important approach for reducing animal use and streamlining testing. The present study evaluated the ability to combine general, immune, and genetic toxicity endpoints into a single study. Specifically, this study evaluated the impact of sheep red blood cell (SRBC) immunization, as part of the T-cell dependent antibody response (TDAR) assay, on organ weights, micronuclei (MN) formation (bone marrow and peripheral blood), and the Comet assay response in the liver of female F344/DuCrl rats treated with cyclophosphamide (CP) a known immunosuppressive chemical and genotoxicant.

Dose-response modeling of early molecular and cellular key events in the CAR-mediated hepatocarcinogenesis pathway.

Low-dose extrapolation and dose-related transitions are paramount in the ongoing debate regarding the quantification of cancer risks for nongenotoxic carcinogens. Phenobarbital (PB) is a prototypical nongenotoxic carcinogen that activates the constitutive androstane receptor (CAR) resulting in rodent liver tumors. In this study, male and female CD-1 mice administered dietary PB at 0, 0.

Studies of styrene, styrene oxide and 4-hydroxystyrene toxicity in CYP2F2 knockout and CYP2F1 humanized mice support lack of human relevance for mouse lung tumors.

Styrene (S) is lung tumorigenic in mice but not in rats. S and its alkene-oxidized metabolite styrene oxide (SO) were not lung toxic in CYP2F2(-/-) [knockout] mice, indicating S-induced mouse lung tumors are mediated through mouse-specific CYP2F2-generated ring-oxidized metabolite(s) in lung bronchioles. The human relevance of the CYP2F MOA was assessed by insertion of a human CYP2F1, 2A13, 2B6 transgene into CYP2F2(-/-) mice; CYP2F1 expression and activity were confirmed in the transgenic (TG) mice.

Lymphatics, tertiary lymphoid organs and the granulomas of Crohn's disease: an immunohistochemical study.

Background: Case studies in the past repeatedly suggested that the fundamental alteration in Crohn's disease occurs in the regional lymphatics of the intestine.

Aim: To evaluate the lymphatic inflammation in Crohn's disease, and to characterise lymphoid aggregates and granulomas in and surrounding lymphatics and blood vasculature.

Methods: Forty-eight tissue blocks from 24 Crohn's disease patients and 23 tissue blocks from 23 control patients were selected.

Neoplasia and granulomas surrounding microchip transponders in Damaraland mole rats (Cryptomys damarensis).

Damaraland mole rats (Cryptomys damarensis) are among the longest-living rodents, with a maximum longevity of approximately 16 years. As one of the few mammals termed eusocial, these animals have been used in behavioral, genetic, metabolic, and physiologic research at the University of Connecticut since 1997. For individual identification at 3 to 4 months of age, mole rats were subcutaneously implanted with microchip transponders (11 mm in length) in the dorsal cervical region.

Cerebral and renal phaeohyphomycosis in a dog infected with Bipolaris species.

Mycotic meningoencephalitis in dogs may manifest as a primary disease of the central nervous system or as a part of disseminated infection. Fungi belonging to the genus Bipolaris are saprophytic plant pathogens and can cause disease in humans. The authors report a case of Bipolaris infection in a dog with granulomatous meningoencephalitis, nephritis, and vasculitis.