engleski

Characteristics of glial cells in diffuse versus focal white matter lesions of 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)], microglia-macrophages [Iba-1, CD68, CD45, LN3 (MCHII)], vessels (MCT1) and pre-oligodendrocytes (Olig2). 1/ On hemateine eosine staining the different types of PVWMI were identified as focal and/or diffuse lesions, 2/ In control cases, MCT1 was expressed primarily in vessel walls and at a very low level in astrocytes of very preterm brains. MCT1 labeling 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 astrogliosis. 5/ Olig2 labeling of preoligodendrocytes decreased in most PVWMI, but it was an inconstant feature as some cases display no decrease. In parallel in the internal capsule of some PVWMI, PS100β positive cell bodies displayed an oligodendrocytic phenotype giving rise to myelin sheets. This study identifies critical differences in glial phenotypic expressions in diffuse compared to focal lesions in PVWMI.

glia; preterm; brain

section 14 -Ischemia and hypoxia