Background Pathological Changes in Minipigs

Abstract

Swine, especially the miniature swine or minipigs, are increasingly being used in preclinical safety assessment of small molecules, biopharmaceutical agents, and medical devices as an alternate nonrodent species. Although swine have been used extensively in biomedical research, there is a paucity of information in the current literature detailing the incidence of background lesions and differences in incidence between commonly used breeds. This article is a collaborative effort between multiple organizations to define and document lesions found in the common breeds of minipigs used for toxicological risk assessment in North America (NA) and the European Union (EU). We retrospectively assessed 10 years of historical control data from several institutions located in NA and EU, covering the period of 2004-2015. Here we report the background lesions with consideration of breed and geographical location. To our knowledge, this is the first report documenting spontaneous background lesions in commonly used breeds of swine in both NA and EU. This report serves as a resource to pathologists and will aid in interpretation of findings and differentiation of background from test article-related changes.

Pigs in Toxicology

“…In Yucatans less than 2 months of age, syncytial alveolar cells and pigmented macrophages were common, which were not reported in animals greater than 6 months old. Inflammatory cell infiltrate increased with age in the Yucatan breed (Helke et al 2015).…”

“…Göttingens also displayed mesothelial hyperplasia and hypertrophy more commonly in animals >6 months of age (Helke et al 2015). Hemorrhage and cardiomyofiber degeneration were common in North American Göttingen minipigs (Helke et al 2015).…”

“…Both Göttingens and Yucatans had inflammatory cell infiltrate of the tongue (Helke et al 2015;Jeppesen and Skydsgaard 2015). Göttingens also had lingual inflammation and myocyte degeneration and necrosis which were more commonly seen in males (Helke et al 2015;Jeppesen and Skydsgaard 2015).…”

“…Pulmonary mineralization, pleural adhesions, and associated fibrosis were seen in Göttingen minipigs (Helke et al 2015;Jeppesen and Skydsgaard 2015). The Hanford breed commonly displayed granulomatous inflammation or granulomas and inflammatory cell infiltrate (Helke et al 2015). Yucatan minipigs also had pulmonary granulomatous inflammation or granulomas but also displayed acute, subacute, and chronic inflammation.…”

“…Pulmonary hemorrhage, inflammatory cell infiltrate, and inflammation (Figure 3), specifically granulomatous and granulomas, were also common in Göttingens. Pulmonary mineralization, pleural adhesions, and associated fibrosis were seen in Göttingen minipigs (Helke et al 2015;Jeppesen and Skydsgaard 2015). The Hanford breed commonly displayed granulomatous inflammation or granulomas and inflammatory cell infiltrate (Helke et al 2015).…”