title: Neurogenesis impairment and increased cell death reduce total neuron number in the hippocampal region of fetuses with Down syndrome.
abstract: We previously obtained evidence for reduced cell proliferation in the dentate gyrus (DG) of fetuses with Down syndrome (DS), suggesting that the hippocampal hypoplasia seen in adulthood may be caused by defective early neuron production. The goal of this study was to establish whether DS fetuses (17-21 weeks of gestation) exhibit reduction in total cell number in the DG, hippocampus and parahippocampal gyrus (PHG). Volumes of the cellular layers and cell number were estimated with Cavalieri's principle and the optical fractionator method, respectively. We found that in DS fetuses all investigated structures had a reduced volume and cell number. Analysis of cell phenotype showed that DS fetuses had a higher percentage of cells with astrocytic phenotype but a smaller percentage of cells with neuronal phenotype. Immunohistochemistry for Ki-67, a marker of cycling cells, showed that DS fetuses had less proliferating cells in the germinal zones of the hippocampus and PHG. We additionally found that in the hippocampal region of DS fetuses there was a higher incidence of apoptotic cell death. Results show reduced neuron number in the DS hippocampal region and suggest that this defect is caused by disruption of neurogenesis and apoptosis, two fundamental processes underlying brain building.
authors: Dipartimento di Fisiologia Umana e Generale, Università di Bologna, Bologna, Italy.
authors: Sandra
authors: S
authors: Guidi
authors: Paola
authors: P
authors: Bonasoni
authors: Claudio
authors: C
authors: Ceccarelli
authors: Donatella
authors: D
authors: Santini
authors: Fabio
authors: F
authors: Gualtieri
authors: Elisabetta
authors: E
authors: Ciani
authors: Renata
authors: R
authors: Bartesaghi
mesh_terms: D001835:Body Weight; D016022:Case-Control Studies; D053148:Caspase 3 / Q000378:metabolism; D002452:Cell Count; D016923:Cell Death; D002454:Cell Differentiation; D049109:Cell Proliferation; D004314:Down Syndrome / Q000473:pathology*; D005260:Female; D005333:Fetus / Q000473:pathology*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007223:Infant; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D009474:Neurons / Q000378:metabolism / Q000473:pathology*; D010751:Phosphopyruvate Hydratase / Q000378:metabolism
chemical_list: D005904:Glial Fibrillary Acidic Protein; D019394:Ki-67 Antigen; D053148:Caspase 3; D010751:Phosphopyruvate Hydratase