Individual hippocampal subfield assessment indicates that matrix macromolecules and gliosis are key elements for the increased T2 relaxation time seen in temporal lobe epilepsy

Autor(es)

Peixoto-Santos, Jose Eduardo ; Kandratavicius, Ludmyla ; Velasco, Tonicarlo Rodrigues ; Assirati, Joao Alberto ; Carlotti, Carlos Gilberto ; Scandiuzzi, Renata Caldo ; Garrido Salmon, Carlos Ernesto ; dos Santos, Antonio Carlos ; Leite, Joao Pereira

• Tipo de documento: Artigo Científico
• Fonte: Epilepsia; v. 58, n. 1, p. 149-159, JAN 2017.
• Citações Web of Science: 8

Resumo

ObjectiveIncreased T2 relaxation time is often seen in temporal lobe epilepsy (TLE) with hippocampal sclerosis. Water content directly affects the effective T2 in a voxel. Our aim was to evaluate the relation between T2 values and two molecules associated with brain water homeostasis aquaporin 4 (AQP4) and chondroitin sulfate proteoglycan (CSPG), as well as cellular populations in the hippocampal region of patients with TLE. MethodsHippocampal T2 imaging and diffusion tensor imaging (DTI) were obtained from 42 drug-resistant patients with TLE and 20 healthy volunteers (radiologic controls, RCs). A similar protocol (exvivo) was applied to hippocampal sections from the same TLE cases and 14 autopsy control hippocampi (histologic and radiologic controls, HRCs), and each hippocampal subfield was evaluated. Hippocampal sections from TLE cases and HRC controls were submitted to immunohistochemistry for neurons (neuron nuclei {[}NeuN]), reactive astrocytes (glial fibrillary acidic protein {[}GFAP]), activated microglia (human leukocyte antigen-D-related {[}HLA-DR]), polarized AQP4, and CSPG. ResultsPatients with TLE had higher invivo and exvivo hippocampal T2 relaxation time. Hippocampi from epilepsy cases had lower neuron density, higher gliosis, decreased AQP4 polarization, and increased CSPG immunoreactive area. In vivo relaxation correlated with astrogliosis in the subiculum and extracellular CSPG in the hilus. Ex vivo T2 relaxation time correlated with astrogliosis in the hilus, CA4, and subiculum, and with microgliosis in CA1. The difference between invivo and exvivo relaxation ratio correlated with mean diffusivity and with the immunopositive area for CSPG in the hilus. SignificanceOur data indicate that astrogliosis, microgliosis, and CSPG expression correlate with the increased T2 relaxation time seen in the hippocampi of patients with TLE. (AU)

• Processo FAPESP: 15/20840-9 - Correlatos histológicos de imagens por ressonância magnética em pacientes com epilepsias farmacorresistentes
• Beneficiário: José Eduardo Peixoto Santos
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 16/17882-4 - Epilepsias farmacorresistentes: desafios diagnósticos, estudo das comorbidades associadas e novas abordagens experimentais
• Beneficiário: João Pereira Leite
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 10/51515-2 - Estudo das relacoes entre populacoes celulares, expressao de aquaporina-4 e sulfato de condroitina com o tempo de relaxamento e taxa de transferencia de magnetizacao no hipocampo de pacientes com...
• Beneficiário: José Eduardo Peixoto Santos
• Modalidade de apoio: Bolsas no Brasil - Doutorado