Glioblastoma Multiforme in Three Baboons (Papio spp.)

Nanomedicine for brain cancer

CNS tumors remain among the deadliest forms of cancer, resisting conventional and new treatment approaches, with mortality rates staying practically unchanged over the past 30 years. One of the primary hurdles for treating these cancers is delivering drugs to the brain tumor site in therapeutic concentration, evading the blood-brain (tumor) barrier (BBB/BBTB). Supramolecular nanomedicines (NMs) are increasingly demonstrating noteworthy prospects for addressing these challenges utilizing their unique characteristics, such as improving the bioavailability of the payloadsviacontrolled pharmacokinetics and pharmacodynamics, BBB/BBTB crossing functions, superior distribution in the brain tumor site, and tumor-specific drug activation profiles. Here, we review NM-based brain tumor targeting approaches to demonstrate their applicability and translation potential from different perspectives. To this end, we provide a general overview of brain tumor and their treatments, the incidence of the BBB and BBTB, and their role on NM targeting, as well as the potential of NMs for promoting superior therapeutic effects. Additionally, we discuss critical issues of NMs and their clinical trials, aiming to bolster the potential clinical applications of NMs in treating these life-threatening diseases.

Research Relevant Conditions and Pathology in Nonhuman Primates

Biomedical research involving animal models continues to provide important insights into disease pathogenesis and treatment of diseases that impact human health. In particular, nonhuman primates (NHPs) have been used extensively in translational research due to their phylogenetic proximity to humans and similarities to disease pathogenesis and treatment responses as assessed in clinical trials. Microscopic changes in tissues remain a significant endpoint in studies involving these models. Spontaneous, expected (ie, incidental or background) histopathologic changes are commonly encountered and influenced by species, genetic variations, age, and geographical origin of animals, including exposure to infectious or parasitic agents. Often, the background findings confound study-related changes, because numbers of NHPs used in research are limited by animal welfare and other considerations. Moreover, background findings in NHPs can be exacerbated by experimental conditions such as treatment with xenobiotics (eg, infectious morphological changes related to immunosuppressive therapy). This review and summary of research-relevant conditions and pathology in rhesus and cynomolgus macaques, baboons, African green monkeys, common marmosets, tamarins, and squirrel and owl monkeys aims to improve the interpretation and validity of NHP studies.

Neoplasia in Three Aye-Ayes (Daubentonia madagascariensis)

Tumours diagnosed in three aged captive aye-ayes (Daubentonia madagascariensis), held in two different institutions, are described. A cerebral glioblastoma was diagnosed based on histological and immunohistochemical findings in one of the animals following initial presentation with bilateral mydriasis, absent pupillary reflex, head tilt and ataxia. A second animal was humanely destroyed due to impaired locomotion associated with spondylosis and a post-mortem diagnosis of cholangiocarcinoma was made based on histology with further confirmation with immunohistochemical labelling for cytokeratin 7. A third aye-aye suffering from dental disease was diagnosed with an oral squamous cell carcinoma following an excisional biopsy from a non-healing wound in the lip. Due to progression of the neoplasia the animal was humanely destroyed and post-mortem examination revealed the presence on an additional unilateral phaeochromocytoma.

Mortality in captive baboons (Papio spp.): a-23-year study

BACKGROUND

We report the causes of mortality for 4350 captive baboons that died or were euthanized due to natural causes during a 23 year period at the Southwest National Primate Research Center.

METHODS

Necropsy records were retrieved and reviewed to determine a primary cause of death or indication for euthanasia. Data was evaluated for morphological diagnosis, organ system, and etiology.

RESULTS

The 20 most common morphologic diagnoses accounted for 76% of the cases, including stillborn (10.8%); colitis (8.6%); hemorrhage (8.4%); ulcer (5.2%); seizures (4.7%); pneumonia (4.2%); inanition (4.1%); dermatitis (3.8%); spondylosis (3.3%); and amyloidosis (3.0%). The digestive system was most frequently involved (21.3%), followed by the urogenital (20.3%), cardiovascular (12.2%), and multisystem disease (10.3%). An etiology was not identified in approximately one-third of cases. The most common etiologies were trauma (14.8%), degenerative (9.5%), viral (8.7%), and neoplastic/proliferative (7.0%).

CONCLUSION

This information should be useful for individuals working with baboons.

Intracranial meningioma in a baboon (Papio spp.)

Meningioma is the most common intracranial non-glial tumour of cats, dogs and man. Few spontaneously arising brain tumours have been reported in non-human primates. This report describes a meningioma in a captive baboon. Clinical signs exhibited by the animal included head pressing, visual impairment and vestibular disease. The tumour arose from the ventral aspect of the cranial cavity and compressed the overlying left side of the cerebellum and brainstem. Microscopically, the mass was characterized by pleomorphic spindle-shaped to polygonal cells arranged in sheaths, vague whorls and occasional papillary structures on vascular cores. Nuclear cytoplasmic invagination, syncytial-like cells and areas of mineralization were also evident. Immunohistochemically, the neoplastic cells expressed vimentin and S-100 protein, but not pancytokeratin, glial fibrillary acidic protein or epithelial membrane antigen. The features of this tumour are similar to those of meningiomas in other species.

Natural pathology of the Baboon (Papio spp.)

BACKGROUND

Baboons are useful animal models for biomedical research, but the natural pathology of the baboon is not as well defined as other non-human primates.

METHODS

A computer search for all morphologic diagnoses from baboon necropsies at the Southwest National Primate Research Center was performed and included all the natural deaths and animals euthanized for natural causes.

RESULTS

A total of 10,883 macroscopic or microscopic morphologic diagnoses in 4297 baboons were documented and are presented by total incidence, relative incidence by sex and age-group, and mean age of occurrence. The most common diagnoses in descending order of occurrence were hemorrhage, stillborn, amyloidosis, colitis, spondylosis, and pneumonia. The systems with the most diagnoses were the digestive, urogenital, musculoskeletal, and respiratory.

CONCLUSION

This extensive evaluation of the natural pathology of the baboon should be an invaluable biomedical research resource.

A review of spontaneous neoplasia in baboons (Papio spp.)

The baboon has become an increasingly important animal model and accurate information on baboon neoplasia is frequently required for biomedical research. To satisfy this demand, a complete literature search was carried out. Two hundred and four spontaneous neoplasms were found in published literature: 53 cases were male (26%), 76 were female (37%); sex was not reported in 75 cases (37%). Ages ranged from 3 months to 31 years (mean 14.1 years) in the 93 cases that reported them. Spontaneous neoplasms have been documented in Papio cynocephalus and Papio hamadryas as well as in most subspecies and hybrid combinations. The organ systems affected in descending order of number of neoplasms were hematopoietic (n = 53, 26%), alimentary (n = 52, 25%), urogenital (n = 35, 17%), integumentary (n = 26, 13%), endocrine (n = 14, 7%), nervous (n = 12, 5%), musculoskeletal (n = 4, 2%) and respiratory (n = 3, 1%). There were five miscellaneous neoplasms (2%) that could not be classified by system. Lymphosarcoma was the most common neoplasm (n = 51, 25%), and adenocarcinomas were second (n = 23, 11%), followed by squamous cell carcinomas (n = 10, 5%). Malignant cases numbered 114 (56%); 87 cases were (43%) benign. The malignancy of three cases (1%) was unreported.