Spontaneous Malignant T-cell Lymphoma in a Young Adult Crl:CD (SD) Rat

EFSA Panel on Genetically Modified Organisms (GMO), Mullins E, Bresson J, Dalmay T, Dewhurst IC, Epstein MM, Firbank LG, Guerche P, Hejatko J, Moreno FJ, Naegeli H, Nogué F, Rostoks N, Sánchez Serrano JJ, Savoini G, Veromann E, Veronesi F, Ardizzone M, Camargo AM, De Sanctis G, Federici S, Fernandez A, Gennaro A, Gómez Ruiz JÁ, Goumperis T, Grammatikou P, Kagkli DM, Lenzi P, Neri FM, Papadopoulou N, Raffaello T. Assessment of genetically modified maize DP202216 for food and feed uses, under Regulation (EC) No 1829/2003 (application EFSA-GMO-NL-2019-159)

Genetically modified maize DP202216 was developed to confer tolerance to glufosinate-ammonium-containing herbicides and to provide an opportunity for yield enhancement under field conditions. These properties were achieved by introducing the mo-pat and zmm28 expression cassettes. The molecular characterisation data and bioinformatic analyses do not identify issues requiring food/feed safety assessment. None of the identified differences in the agronomic/phenotypic and compositional characteristics tested between maize DP202216 and its comparator needs further assessment, except for the levels of stearic acid (C18:0), which do not raise nutritional and safety concerns. The GMO Panel does not identify safety concerns regarding the toxicity and allergenicity of the PAT and ZMM28 proteins as expressed in maize DP202216, and finds no evidence that the genetic modification would change the overall allergenicity of maize DP202216. In the context of this application, the consumption of food and feed from maize DP202216 does not represent a nutritional concern in humans and animals. The GMO Panel concludes that maize DP202216 is as safe as the comparator and non-GM reference varieties tested, and no post-market monitoring of food/feed is considered necessary. In the case of accidental release of viable maize DP202216 grains into the environment, this would not raise environmental safety concerns. The post-market environmental monitoring plan and reporting intervals are in line with the intended uses of maize DP202216. The GMO Panel concludes that maize DP202216 is as safe as its comparator and the tested non-GM reference varieties with respect to potential effects on human and animal health and the environment.

Differences in Types and Incidence of Neoplasms in Wistar Han and Sprague-Dawley Rats

A substantial quantity of data on Sprague-Dawley (SD) and Hannover Wistar rats strains have been published concerning their source, diet, and housing conditions, as well as the incidences of nonneoplastic lesions and neoplasms observed in different laboratories. Differences between the commonly used rat strains provided by different breeders (i.e., CD (SD) vs. Harlan Sprague-Dawley strain or Crl: WI(Han) vs. Wistar Hannover (Han)-derived strain, continued breeding by RCC Ltd., Switzerland, thereafter continued breeding by Harlan) may include, but are not limited to, body weight, incidence, and onset of major nonneoplastic lesions and neoplasms, and these can impact the development of a nonclinical safety program. Fisher 344 (F344) and SD rat strains generally have the highest tumor incidences, exceeding that in Wistar rats. Certain tumors are more commonly observed in one strain, and for some, the difference in incidence may be so significant that the tumor may even be considered characteristic for a specific strain (e.g., thymoma in Wistar and amphophilic renal adenoma in SD).

COMPARISON BETWEEN THORACIC RADIOGRAPHIC FINDINGS AND POSTMORTEM DIAGNOSIS OF THORACIC DISEASES IN DYSPNEIC COMPANION RATS (RATTUS NORVEGICUS)

Companion rats are often presented to veterinarians for respiratory difficulties. Dyspnea in rats is most commonly due to infectious pneumonia, and thoracic neoplasia can go undiagnosed ante mortem due to a mistaken interpretation of pneumonia. In domestic carnivores, pulmonary nodular patterns have been shown to correlate with lung neoplastic diseases and infectious diseases. The main objective of this retrospective case series study was to determine whether certain radiographic criteria could be correlated with the presence of thoracic infectious disease and neoplastic disease in companion rats. A secondary objective was to determine whether the patient's sex and age were different between rats diagnosed with infectious versus neoplastic disease. Medical records and thoracic radiographs of dyspneic companion rats presented to the University of California at Davis, William R. Pritchard Veterinary Medical Teaching Hospital during the time period from January 2000 to December 2014 were reviewed. Rats with postmortem confirmation of thoracic lesions were included in the study. Thoracic radiographs were evaluated for positioning, lesion distribution, lung lobe involved, pulmonary pattern, mediastinal and pleural lesions by three observers blinded to diagnosis. Thirty rats were included in the study, including 23 rats with an infectious disease and seven with neoplasia. Mediastinal lesions were significantly more prevalent in the group diagnosed with thoracic neoplasia (P = 0.031), in particular cranially (P = 0.048). Although there was an overlap between the two groups, findings indicated that the presence of cranial mediastinal lesions may be helpful for differentiating neoplastic from infectious disease in rats.

Spontaneously occurring lymphohematopoietic tumors in three young Sprague Dawley rats

To assess the toxicological and pharmacological effects of chemicals, it is important to know what kinds of neoplasms naturally occur in the early life of laboratory animals. In the present study, we identified three spontaneous hematopoietic tumors in three of 52 young female Sprague-Dawley rats used in a pharmacological study. These cases included two rats (Case 1 and 2) from a sesame oil-treated group and one rat (Case 3) from a chemical-treated group in the same single gavage study. Case 1 rapidly lost body weight at 13 weeks of age without any clinical signs and died. Round lymphoid tumor cells were found in the spleen, liver, bone marrow, and pancreas. The tumor cells were immunohistochemically positive for CD3 and PCNA, which is suggestive of malignant T-cell lymphoma. Cases 2 and 3 had rapid body weight loss at 14 and 16 weeks of age, respectively, exhibited severe anemia, hypolocomotion, and decreased body temperature, and were euthanized due to a poor prognosis based on severe clinical signs. Pleomorphic large tumor cells were found in the spleen, liver, bone marrow, lymph nodes, heart, kidneys, lung, pancreas, adrenal glands, pituitary gland, ovaries, Harderian gland, and/or eyes. The tumor cells were immunoreactive for CD34, lysozyme, and PCNA, which is suggestive of myeloid leukemia. These cases might provide useful historical control information for rat toxicity studies.