Concerns about pathology expertise and data quality

Reproducibility of in vivo research using the mouse as a model organism depends on many factors, including experimental design, strain or stock, experimental protocols, and methods of data evaluation. Gross and histopathology are often the endpoints of such research and there is increasing concern about the accuracy and reproducibility of diagnoses in the literature. To reproduce histopathological results, the pathology protocol, including necropsy methods and slide preparation, should be followed by interpretation of the slides by a pathologist familiar with reading mouse slides and familiar with the consensus medical nomenclature used in mouse pathology. Likewise, it is important that pathologists are consulted as reviewers of manuscripts where histopathology is a key part of the investigation. The absence of pathology expertise in planning, executing and reviewing in vivo research using mice leads to questionable pathology-based findings and conclusions from studies, even in high-impact journals. We discuss the various aspects of this problem, give some examples from the literature and suggest solutions.

Animal models are essential research tools in modern biomedical research, but there are concerns about their lack of reproducibility and the failure of animal data to translate into advances in human medical therapy. A major factor in improving experimental reproducibility is thorough communication of research methodologies. The recently published ARRIVE guidelines outline basic information that should be provided when reporting animal studies. This paper builds on ARRIVE by providing the minimum information needed in reports to allow proper assessment of pathology data gathered from animal tissues. This guidance covers aspects of experimental design, technical procedures, data gathering, analysis, and presentation that are potential sources of variation when creating morphological, immunohistochemical (IHC) or in situ hybridization (ISH) datasets. This reporting framework will maximize the likelihood that pathology data derived from animal experiments can be reproduced by ensuring that sufficient information is available to allow for replication of the methods and facilitate inter-study comparison by identifying potential interpretative confounders.

Agencies responsible for environmental protection are tasked with developing regulatory guidance that is based on the best available scientific evidence. Histopathology is a common endpoint in toxicologic bioassays; however, because of the subjective nature of this endpoint, and the advanced level of specialized training required for its effective utilization, the reliability of histopathology data can be inconsistent. Consequently, mechanisms for evaluating such data on a case-by-case basis are needed. The purposes of the present review are to describe a methodology that can be used to evaluate the credibility of histopathology findings and to discuss the results of such assessments as applied to real-world data collected from the scientific literature. A key outcome of these efforts was the finding that only 54% of the studies examined contained histopathology data that were considered to be either highly credible or credible, whereas data in 46% of those studies were of equivocal, dubious, or no credibility. In addition, the results indicated that the quality of the data examined tended to decline during the past 15 yr. The ultimate goals of the present review are to draw attention to reliability issues that can affect histopathology results, provide recommendations to improve the quality of this endpoint, and suggest an approach for the expeditious and judicious use of histopathology data in the weight-of-evidence determinations required for hazard and/or risk assessment. This exercise was conducted initially as part of a SETAC Pellston Workshop™ entitled "Environmental Hazard and Risk Assessment Approaches for Endocrine-Active Chemicals (EHRA): Developing Technical Guidance Based on Case Studies to Support Decision Making" that was held in Pensacola, Florida (USA) from 31 January to 5 February 2016. Environ Toxicol Chem 2017;36:601-611. © 2016 SETAC.