RESUMO
Multiple sclerosis (MS) is an idiopathic demyelinating disease in which meningeal inflammation correlates with accelerated disease progression. The study of meningeal inflammation in MS has been limited because of constrained access to MS brain/spinal cord specimens and the lack of experimental models recapitulating progressive MS. Unlike induced models, a spontaneously occurring model would offer a unique opportunity to understand MS immunopathogenesis and provide a compelling framework for translational research. We propose granulomatous meningoencephalomyelitis (GME) as a natural model to study neuropathological aspects of MS. GME is an idiopathic, progressive neuroinflammatory disease of young dogs with a female bias. In the GME cases examined in this study, the meninges displayed focal and disseminated leptomeningeal enhancement on magnetic resonance imaging, which correlated with heavy leptomeningeal lymphocytic infiltration. These leptomeningeal infiltrates resembled tertiary lymphoid organs containing large B cell clusters that included few proliferating Ki67+ cells, plasma cells, follicular dendritic/reticular cells, and germinal center B cell-like cells. These B cell collections were confined in a specialized network of collagen fibers associated with the expression of the lympho-organogenic chemokines CXCL13 and CCL21. Although neuroparenchymal perivascular infiltrates contained B cells, they lacked the immune signature of aggregates in the meningeal compartment. Finally, meningeal B cell accumulation correlated significantly with cortical demyelination reflecting neuropathological similarities to MS. Hence, during chronic neuroinflammation, the meningeal microenvironment sustains B cell accumulation that is accompanied by underlying neuroparenchymal injury, indicating GME as a novel, naturally occurring model to study compartmentalized neuroinflammation and the associated pathology thought to contribute to progressive MS.
Assuntos
Linfócitos B/imunologia , Modelos Animais de Doenças , Meninges/imunologia , Esclerose Múltipla Crônica Progressiva/imunologia , Animais , Linfócitos B/patologia , Cães , Meninges/patologia , Esclerose Múltipla Crônica Progressiva/patologiaRESUMO
In this retrospective descriptive study, we characterized the clinical, histologic, and immunohistochemical features of 13 cases of canine gallbladder neuroendocrine carcinoma (GB-NEC). Immunohistochemical stains for neuroendocrine (neuron-specific enolase [NSE], chromogranin A, synaptophysin) and gastrin markers were evaluated, and clinicopathologic and follow-up data were obtained for all cases. The average age at diagnosis was 8.9 y, and breeds included 6 Boston Terriers, 2 Bichon Frise, 1 Poodle, 1 English Bulldog, 1 French Bulldog, and 2 mixed-breed dogs. Boston Terriers were overrepresented in this cohort, and therefore a breed predilection is possible. Most dogs were presented with emesis and elevated liver enzyme activities: 13 of 13 had elevated alanine aminotransferase and alkaline phosphatase activities; 8 of 13 had elevated aspartate aminotransferase activity; 7 of 13 had elevated gamma-glutamyl transferase activity. Abdominal ultrasound and/or exploratory surgery revealed a gallbladder mass. All neoplasms had similar histologic features and positive immunoreactivity for NSE, chromogranin A, synaptophysin, and gastrin. Vascular invasion was noted in 8 of 13 neoplasms, and metastasis was present in 6 of 13 cases (4 hepatic and 2 pulmonary metastases). The median survival time was 3.7 y in patients who died; 5 of 8 deaths were directly attributed to the GB-NEC, 3 of which had metastatic spread. GB-NECs have the potential to metastasize; however, surgical excision may be curative in a subset of dogs.