engleski

“Spatio-temporal glial features in non cystic white matter lesions of preterm infants“

Non cystic periventricular white matter injuries (PWMI) are the main histological brain lesions currently observed in preterm infants. Recent studies have 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 non-cystic PWMI on brain tissue (n=20) obtained from very preterm (24-29 gestational weeks gw) and preterm (30-35gw) infants compared to controls (n=6). Different antibodies were used on serial sections by single or double immunolabelings for astrocytes [GFAP, monocarboxylate transporter-1 (MCT1) ], microglia-macrophages [Iba-1, CD68, CD45, LN3 (MCHII) ], vessels (MCT1-CD34), pre-oligodendrocytes (Olig2) and axonal neurofilaments (SMI311) 1) In very preterm brains, hemateine eosine and immunostaining showed different types of PWMI identified at the level of crossroads in the white matter: at the level of semi-oval center (C2 according to Judas and Kostovic, 2003), spongiosis and at the level the junction internal capsule-external capsule (C1), necrosis whereas in preterm brains, PWMI were more dispersed within the white matter. These injured areas displayed an intense microglial-macrophage activation (Iba-1+, CD68+, CD45+, LN3-) associated with rather non reactive GFAP+astrocytes expressing a low level of MCT1 compared to normal cases. In parallel, SMI311+ axonal degenerative spheroids were detected. 2) In preterm brains, necrotic areas were not restricted to crossroads but were dispersed in the white matter and displays large GFAP+ astrocytes (geminocytes) and a restricted microglial reaction. 3) Olig2 labeling of preoligodendrocytes decreased in most PWMI, but it was an inconstant feature as some cases display no decrease. This study identifies critical differences in glial phenotypic expressions in non cystic lesions PWMI of very preterm brain compared to preterm brain.

preterm; glia; non-cystic injury; preterm

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