engleski

Evaluation and pattern of astroglia, microglia-macrophages and oligodendrocytes in diffuse and focal periventricular white matter lesions in human preterm infants.

Focal and diffuse periventricular white matter injuries (PVWMI) are the main histological brain lesions detected in preterm infants. Recent studies shown that children born very preterm were more likely to develop neurological, cognitive and/or behavioral handicaps than children born preterm. Our study analysed different phenotypic expression of glial cells observed in diffuse and focal PVWMI on brain tissue (n=28) obtained from very preterm (24-30 gestational weeks gw) and preterm (31-35gw) infants compared to controls. Different antibodies were used on serial sections by single or double labelings for astrocytes [GFAP, monocarboxylate transporter-1 (MCT1), PS100beta], microglia-macrophages [Iba-1, CD68, CD45, LN3 (MCHII) ], vessels (MCT1) and oligodendrocytes-myelin (Olig2, PS100beta, MBP). 1/ On hemateine eosine staining the different types of PVWMI were identified as focal and/or diffuse lesions. 2/ In the control cases, MCT1 was expressed primarily in vessel walls and at a very low level in astrocytes of very preterm brain. MCT1immunolabeling increased with age in astrocytes in the white matter of preterm brain. 3/ Diffuse lesions displayed a loss in astrocytic cell bodies and processes associated with a microglial-macrophage activation. MCT1 labeling was not present in most vessel walls and in astrocytes in PVWMI in very preterm brain whereas some labelling was present in preterm brain. 4/ Focal lesions displayed a high density of macrophages associated with a strong astroglial activation. 5/ Olig2 labeling of preoligodendrocytes decreased is the PVWMI in most preterm neonates, but it was an inconstant feature as some cases display no decrease. In parallel in PVWMI some PS100beta positive cell bodies displayed an oligodendrocytic phenotype giving rise to myelin sheets in the internal capsule. This study identifies critical differences in glial phenotypic expressions in diffuse compared to focal lesions in PVWMI.

glia; preterm; brain

Publication ref.: 9e Colloque de la Société des Neurosciences, 041.21 , 2009