A Brief Review of Infrequent Spontaneous Findings, Peculiar Anatomical Microscopic Features, and Potential Artifacts in Göttingen Minipigs

Abstract

Minipigs are now used in greater numbers in contract research organizations (CROs) as well as in the pharmaceutical industry. Most CROs or pharmaceutical companies use the Gö ttingen minipig, which displays a number of important background lesions. This review will discuss some of the more infrequent minipig background changes. Porcine stress syndrome is an autosomal recessive pharmacogenetic disorder in minipigs causing malignant hyperthermia and muscle necrosis. Possible triggers, clinical pathology as well as heart, muscle, liver, lung, and kidney histopathology are discussed. Additional spontaneous changes, background findings, and peculiar anatomical and histological features include thrombocytopenic purpura syndrome, spontaneous glomerulonephritis, osteochondritis, ellipsoids, or Schweigger-Seidel sheaths in the spleen, as well as the presence of a perimesenteric plexus adjacent to mesenteric lymph nodes, squamous epithelial metaplasia of the salivary gland, and cupping of the optic disk in the minipig eye. In order to maximize the data gained from minipig studies, the interpretation of pathology findings requires the input of experienced pathologists who understand the significance of artifacts and spontaneous, background lesions in minipigs and can distinguish these from induced lesions.

Renal Papillary Rarefaction: An Artifact Mimicking Papillary Necrosis

“…In summary, we are describing an uncommon renal artifact that can be very subtle and its interpretation requires the knowledge of experienced pathologists who understand the spectrum of variation seen in processed renal tissues and who are able to distinguish artifactual alterations from treatment induced lesions. 15 Pathology texts often do not contain discussions or illustrations of unusual tissue artifacts. Therefore, it is important to bring difficult diagnostic observations like the described rat renal papillary rarefaction to the attention of veterinary pathologists, reading or reviewing nonclinical rodent studies.…”

International Harmonization of Nomenclature and Diagnostic Criteria (INHAND): Nonproliferative and Proliferative Lesions of the Minipig

“…The red pulp contains pale eosinophilic, contractile, phagocytic structures surrounding splenic capillaries, which are known as periarteriolar macrophage sheaths, splenic ellipsoids, or Schweigger-Seidel sheaths, which can be quite prominent. 29,71 Their function is clearance of blood-borne particles. Extramedullary hematopoiesis may be seen in juveniles up to 6 weeks old or as a response to systemic disease such as hemorrhagic syndrome.…”

“…Extramedullary hematopoiesis may be seen in juveniles up to 6 weeks old or as a response to systemic disease such as hemorrhagic syndrome. 7,29 Accessory spleens may be found in the gastrosplenic ligament. 71 A cross-section through the thickest part of the spleen should be examined histologically (Figures 6.4 and 6.5).…”

“…In addition, the mesenteric lymph nodes are supplied by a prominent perimesenteric plexus. 29 This lymph node should be sampled in all studies as it can reflect the inflammatory state of the gastrointestinal tract. 69 It is common practice for the mandibular lymph node to be examined as a representative peripheral lymph node.…”

A new technique for minimal invasive complete spinal cord injury in minipigs

“…In addition, surgical and analytical instrumentations for interventions, as well as therapeutic devices such as electrodes and pacemakers in large animals such as minipigs are similar or even equal to the ones used in humans. Of particular interest for preclinical research and development is the Göttingen minipig strain, due to its gentle disposition and good training success rates, and due to the tolerance of even severe neurological deficits [ 15 ]. In the present study, we describe a new, minimal invasive, computed tomography (CT)-guided and controlled balloon compression technique for Göttingen minipigs.…”