Toxicologic Pathology最新文献

The pace of technological innovation in the pharmaceutical industry, like in many other sectors, is accelerating rapidly. This is not only reshaping how pharmaceutical Research and Development (R&D) is conducted (e.g., introduction of novel models, endpoints, and instrumentation) but also influencing the types of therapeutic modalities being developed. In addition, societal and regulatory expectations have evolved to emphasize approaches that align with the 4Rs principles (Replacement, Reduction, Refinement, and Responsibility) and to encourage the replacement of animal testing with new approach methods (NAMs) through the FDA Modernization Act 2.0. While innovation, societal changes, and regulatory evolution are not new, what stands out is the unprecedented speed and scale at which these transformations are occurring. This acceleration is fueled predominantly by groundbreaking technological advancements (e.g., artificial intelligence, deep learning, communication tools, and digital pathology) in the context of rapidly changing societal dynamics such as globalization, social networking, and the increase in remote working. Given these potentially disruptive changes, it is essential to consider how toxicologic pathologists need to adapt. More importantly, how can they leverage these advancements to contribute even more significantly to the discovery and development of novel, safe, and effective medicines? In essence, what types of toxicologic pathologists will the pharmaceutical industry require in the future?

The histopathologic evaluation of regulatory toxicity studies using artificial intelligence (AI) has the potential to increase study efficiency. For example, AI could initially identify and exclude all organs without histopathologic lesions, allowing pathologists to focus solely on evaluating organs with identified lesions. In this study, whole slide images (WSIs) of liver sections from 58 different rat toxicity studies were collected, along with their corresponding histopathologic lesion diagnoses. Each WSI was labeled as either "lesion" or "no lesion" based on the presence or absence of reported histopathologic lesions. Multiple instance learning (MIL) approaches, including a transformer variant, were tested to predict lesions within a weakly supervised framework. Both methods achieved acceptable to excellent area under the receiver operating characteristic curve (AUROC) scores. Heatmap overlays were employed to visually assess the MIL model's effectiveness in detecting lesions, confirming the accuracy of targeted areas on the WSIs. In addition, using transfer learning principles, the MIL model initially developed for liver WSIs was adapted to kidney WSIs, demonstrating the model's versatility. This study showcases the application of weakly supervised learning for lesion detection in rat WSIs from toxicity studies, with the potential to significantly enhance the efficiency of the histopathologic evaluation process.

The Cause of Death in Non-Rodents (CODN) Working Group is an initiative under the Scientific and Regulatory Policy Committee (SRPC) of the Society of Toxicologic Pathology (STP), focused on understanding existing practices and expectations among pharmaceutical companies, academic entities, and contract research organizations (CROs) when it comes to identifying and reporting the "Cause of Death" (COD) or moribundity for early or unplanned necropsies in non-rodent animal species (mainly non-human primates [NHP] and dogs) within both GLP (Good Laboratory Practice) and non-GLP toxicity studies. A survey was sent out to STP members to collect data on industry practices for determining COD in animals that underwent unscheduled euthanasia or were found deceased. Other non-rodent animals (such as pigs and rabbits) were also included to evaluate different approaches taken with various species. The insights obtained led to the development of "Points to Consider" for establishing and documenting the COD in large animal toxicity studies. Four key considerations include utilizing information from both control and treated animals in the study, consideration of COD for cohabiting or co-shipped non-study animals, including additional evaluations to help rule-in or rule-out specific causes, and recording the COD consistently in pathology databases or reports as a standard practice.

Two dark and raised foci were observed on the left hemisphere of the brain of a 3-year-old cynomolgus monkey during the routine necropsy procedures of a preclinical toxicity study. Microscopic examination revealed a lesion in the cerebral cortex at the junction of the parietal and occipital lobes, consisting of disorganized, but generally well-circumscribed collections of mixed glial and neuronal cells within a fibrillar stroma. Numerous eosinophilic granular bodies, brown pigment-laden macrophages, and lymphocytic infiltrates were also noted. Immunohistochemical staining for glial fibrillary acidic protein, neurofilament, and Ki-67, as well as histochemical stains Masson's Trichrome and Klüver-Barrera confirmed the presence of both glial and neuronal cells within a collagenous stroma, without significant proliferation. Both histopathological and immuno/histochemical stains were consistent with a glioneuronal hamartoma. This report describes the first case of such a lesion in a nonhuman primate.

Toxicologic pathologists play a crucial role in the evaluation of animal studies for drugs, environmental chemicals, medical devices, and other agents to determine their safety and potential toxic effects. A significant challenge in this domain is the differentiation between incidental or procedural changes and genuine treatment-related effects. Correct identification and interpretation of such findings are essential to ensure that safety assessments are accurate and reliable for subsequent approval for human use. This review presents several cases in which non-test item-related findings were encountered. By examining procedure-related findings and considering spontaneous background pathology, we underscore the need for meticulous pathological evaluation and proper contextual understanding to avoid misinterpretations that could lead to erroneous conclusions about a substance's safety profile. The insights shared in this review aim to enhance the proficiency of toxicologic pathologists in recognizing and managing various interpretative challenges, with the goal of ultimately improving the accuracy of toxicological assessments, thereby contributing to the safe development of new therapeutics and medical devices and sound characterization of potentially hazardous substances in our environment.

Medical devices represent a complex category of medicinal products with varying definitions depending on the regional jurisdiction of regulatory agencies. A common aspect of these definitions is that a medical device is intended to be used for specific medicinal purpose where the primary intended action of the device is not achieved through pharmacologic (or other chemical) means. While regional regulatory frameworks for medical devices are different than for pharmaceutical or biological products, medical device manufacturers are required to evaluate the safety and performance of these products in the context of their intended use. In biological safety evaluation, histopathology plays a relevant role in assessing medical device biocompatibility. This manuscript provides a broad overview of biocompatibility assessment with a deeper look at the role of the toxicologic pathologist in assessing innovative and emerging bone therapies. The content of this manuscript is based on individual presentations delivered at the 2023 International Academy of Toxicologic Pathology (IATP) Satellite Symposium held in conjunction with the Annual Congress of the European Society of Toxicologic Pathology (ESTP) on 26 September, in Basel, Switzerland.

The central (CNS) and peripheral (PNS) nervous systems of vertebrates represent divisions of a continuous, body-wide communication grid based on conserved principles of structural organization. Discrete neuroanatomic regions within this grid are associated with specific neural functions, so distinct patterns of neurological dysfunction ("problems") can provide guidance regarding neural regions to evaluate beyond those in published sampling schemes or institutional standard operating procedures. Each neurological problem or syndrome (i.e., a group of in-life signs indicating that a given neuroanatomic region is damaged) is associated with a particular list of differential diagnoses and causes. Vulnerability of neural cells and tissues is influenced by intrinsic tissue properties (e.g., high metabolic rates of neurons, presence of blood:tissue barriers, degree of collateral vascular supply) and extrinsic factors (bone protuberances and connective tissue partitions impinging on neural surfaces, fluid flow patterns in the cerebroventricular system and meninges, etc.). In the toxicologic pathology setting, expansion (when warranted) of routine neural sampling protocols to collect additional anatomic regions correlated to a specific neurological problem improves the likelihood that a neuropathological evaluation will identify lesions and causes responsible for neurological conditions as well as detect findings related to potential test item-related neurotoxicity.

The first session of the 2025 European Society of Toxicologic Pathology (ESTP) Congress reviewed routine and specialized methods for microscopic evaluation of neural tissues during nonclinical studies. Three longer presentations reviewed brain sampling approaches in safety assessments, including an example to accentuate topographical analysis and integration of toxicology data; specific brain and spinal cord sampling for molecular and protein analyses; and an overview of technical aspects of intraparenchymal drug delivery. Four shorter talks discussed the uses, advantages, disadvantages, and interpretation of several special neurohistological techniques (stains and immunohistochemical markers) for assessing test item-associated responses. Common special methods used (when warranted) for nonclinical studies include Fluoro-Jade or silver stains for detecting neuronal death, Luxol fast blue (LFB) for examining myelin, anti-glial fibrillary acidic protein (GFAP) to demonstrate reactive astrocytes, and anti-ionized calcium-binding adaptor molecule 1 (IBA1) to highlight reactive microglia and macrophages, though alternatives methods were described. The last presentation discussed artificial intelligence as an aid in detecting subtle toxicant-induced lesions during digital pathology analyses (using the Olney lesion [acute neuronal vacuolation and necrosis in the cerebral cortex] as an example). Taken together, talks in this session provided a cohesive overview of traditional and innovative approaches to facilitate microscopic evaluation for potential neurotoxicity in nonclinical studies.

In this case presentation, the speaker and co-authors represented a group of scientists engaged in a cross-institutional precompetitive working group focused on elucidating a novel background change in the basal nuclei of Beagle dogs. The group's ongoing efforts since first publication of the lesion in 2024 enabled further characterization of the lesion and revealed additional incidences in control animals. The characterization, including newly discovered lesion features, and terminology of the condition were outlined and suggestions for interpretation in nonclinical toxicity studies were given.