Presented at the Neonatal Society 2003 Spring Meeting.
Kennea NL, Fisk NM, Edwards AD, Mehmet H
Division of Paediatrics, Obstetrics and Gynaecology, Imperial College London,
Hammersmith Hospital, Du Cane Road, London, UK.
Introduction: The aetiology of neonatal brain injury remains incompletely understood although both hypoxia-ischaemia and inflammation are implicated as causes. The brain, unlike many tissues, has limited capacity for self-repair and so there has been great interest in the possibility of transplanting cells to replace those lost through injury. Although the immature, developing brain may provide a particularly favourable environment for functional transplant integration, little research has considered specific strategies for brain repair in the newborn infant. Recently a population of circulating mesenchymal stem cells (MSC) has been isolated from human first trimester fetal blood. These cells are mesodermal in origin and have a phenotype similar to bone marrow-derived MSC (CD45-, CD34-, CD68-, vWF-, CD14-, HLA-DR-, SH2/3/4+, CD105+, Fibronectin+, Vimentin+, Laminin+) (1). They have considerable proliferative capacity and can differentiate into osteogenic, chrondrogenic and adipogenic lineages.
Aims of the project: The aim of this project is to determine whether MSC can differentiate into neurons and oligodendrocytes, and ultimately whether they can integrate into the damaged central nervous system and functionally improve outcome in relevant models of injury to the developing brain.
Methods: We examined the growth kinetics of MSC in medium with serum. In time-course and dose-response experiments we examined the effects of serum withdrawal, and whether the addition of retinoids, growth factors including basic fibroblastic growth factor and platelet-derived growth factor support survival and/or promote differentiation into specific neural lineages. Finally, conditioned medium from neural cell lines was applied to MSC to determine if neural cell-derived soluble factors could influence differentiation. Neural cell phenotypes were characterised on the basis of cell morphology combined with immunocytochemistry and RT-PCR analysis of lineage specific markers.
Results and Conclusions: MSC proliferated for more than 20 passages with no change in doubling time and no apparent phenotypic change. Serum withdrawal alone did not promote neural differentiation but rather triggered apoptosis. Chemical induction promoted MSC differentiation towards a neuronal phenotype, while experiments using conditioned media from neural cell lines demonstrated dramatic morphological and phenotypic differentiation of >50% MSC along the oligodendrocyte lineage.
References
1. Campagnoli C, Roberts IA, Kumar S, Bennett PR, Bellantuono I, Fisk NM. Blood 2001; 98(8): 2396-402.