Abstract
Hooray for Histopathology!
The biologically controlled process of the conversion of ions to mineral and the mechanisms that control the mineral form (tooth or bone, eg) is biomineralization. Various animal models of tooth development have been studied, and mice are common models because their incisors grow continuously. Similarly, zebrafish tooth development is studied; although they lack oral teeth, zebrafish have pharyngeal teeth that are replaced every 11 to 13 days during their lifespan. Dental enamel defects have been reported in both animal models. 2
In this seminal research report and review of biomineralization, Vogel and coauthors present their intricate findings and review biomineralization in mice and humans (“Amelogenesis Imperfecta and Other Biomineralization Defects in Fam20a and Fam20c Null Mice”). They have many techniques at their disposal for phenotyping knockout mice, including beta-galactosidase staining and microcomputed tomography; however, it was application of routine pathology skills that identified notable phenotypes. The Fam20a -/- mice demonstrated chalky, white, pitted teeth at necropsy and showed severe defects in enamel production. Furthermore, these mice also displayed widespread ectopic calcification of muscular arteries in most locations in the body. In contrast, the Fam20c -/- mice revealed enamel defects, an absence of ectopic calcification of arteries, hypophosphatemia, and the presence of thickened growth plates. Vogel and coauthors provide a fascinating review of the subject of biomineralization and its multifactorial causes and remind us that macroscopic and histopathologic evaluation is invaluable to include in high-throughput phenotype screening protocols.
Vaccine-Associated Respiratory Disease: Investigation of Vaccine Versus Natural Exposure
The science of influenza is evolving nearly as rapidly as the virus. This is exemplified by the timely article by Gauger et al in this edition of Veterinary Pathology (“Kinetics of Lung Lesion Development and Pro-inflammatory Cytokine Response in Pigs With Vaccine-Associated Enhanced Respiratory Disease Induced by Challenge With Pandemic (2009) A/H1N1 Influenza Virus”). A former article by this group 4 describes vaccine-associated enhanced respiratory disease, and here the authors investigate the pathogenesis of that enhancement. Antibody-dependent enhancement of infection could have enormous consequences for both veterinary and medical vaccine development and strain selection. This research begs the question of how a pattern of natural exposure to seasonal influenza influences the clinical outcome in subsequent exposures and whether natural or vaccine exposure contributes to future pandemic strains. Two recent outbreaks of influenza punctuate the need for effective antiviral prophylaxis: the emergence of fatal pneumonia in late 2011 affecting 162 New England harbor seals 1 and fatalities associated with new variant swine influenza, H3N2v. In Ohio, 102 of 288 cases of human infection with this new strain have been identified, and most had exposure to pigs. 3
Another First for Primate Pathology
To improve understanding of the causes of morbidity and mortality in nonhuman primates (NHP), proceedings from a special ACVP-sponsored workshop, with 20 case reports accompanied by digitally scanned slides, are published in this issue (“Meeting Report: Spontaneous Lesions and Diseases in Wild, Captive-Bred, and Zoo-Housed Nonhuman Primates and in Nonhuman Primate Species Used in Drug Safety Studies”). The scanned-slide link and case reports will be an invaluable educational resource.
Providing an overview were Drs Linda Lowenstine and Dick Montali, trailblazers in this area and responsible for the popular Primate Pathology Workshops. In 2003, the journal Toxicologic Pathology published several influential articles highlighting background findings and pathology related to the age, source, strain, and disease status of NHPs. 5,6 The 2011 ACVP workshop complemented and updated this work. The authors recognized that some diseases are either specific to the captive situation or exacerbated by it and that learning of these potential confounding pitfalls will enhance the design and interpretation of biomedical studies and aid in the improved management of NHPs in captivity as well as their preservation in the wild.