RESUMO
OBJECTIVE: To identify cells with neural crest properties in mesenchymal populations isolated from human periodontal ligament. BACKGROUND: Evidence from tracing experiments on animal embryos revealed proof that dental tissues are among the homing sites of craniofacial neural crest migratory cells. In humans, similar migratory cells were found in early embryos, but whether these cells are progeny of oral multipotent stem cells needs to be confirmed. Searching for the cells with neural crest characteristics in periodontal ligament mesenchymal populations can lead to a solution to the problem. MATERIAL AND METHODS: Populations from the human periodontal ligament were cultured in media supplemented with various concentrations of fetal bovine serum (FBS); assays were performed to evaluate the expression of neural crest, mesenchymal and multipotency genes. RESULTS: In periodontal ligament populations cultured in the standard expansion medium containing minimal amounts of FBS (0.5% or 1%) or lacking FBS, growing numbers of epithelial-like cells emerged, co-expressing neural crest-specific (p75, HNK-1, SOX10), the epithelialization (E-cadherin) and mesenchymal (CD73 and CD105) markers. CONCLUSION: The human periodontal ligament contains a subpopulation of dormant neural crest-like cells, which can be highlighted by culturing at FBS concentrations below 2% or in a serum-free medium.
Assuntos
Crista Neural/citologia , Ligamento Periodontal/citologia , Adolescente , Antígenos CD57/metabolismo , Células Cultivadas , Feminino , Citometria de Fluxo , Imunofluorescência , Humanos , Masculino , Proteínas do Tecido Nervoso/metabolismo , Crista Neural/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Receptores de Fator de Crescimento Neural/metabolismo , Adulto JovemRESUMO
Human adult dental pulp stem cells (DPSCs) are self-renewing stem cells that originate from the neural crest during development and remain within the dental pulp niche through adulthood. Due to their multi-lineage differentiation potential and their relative ease of access they represent an exciting alternative for autologous stem cell-based therapies in neurodegenerative diseases. In animal models, DPSCs transplanted into the brain differentiate into functional neurons or astrocytes in response to local environmental cues that appear to influence the fate of the surviving cells. Here we tested the hypothesis that DPSCs might be able to respond to factors present in the retina enabling the regenerative potential of these cells. We evaluated the response of DPSCs to conditioned media from organotypic explants from control and chemically damaged rat retinas. To evaluate cell differentiation, we analyzed the expression of glial fibrillary acidic protein (GFAP), early neuronal and retinal markers (polysialic acid-neural cell adhesion molecule (PSA-NCAM); Pax6; Ascl1; NeuroD1) and the late photoreceptor marker rhodopsin, by immunofluorescence and reverse transcription polymerase chain reaction (RT-PCR). Exposure of DPSC cultures to conditioned media from control retinas induced a 39% reduction on the number of DPSCs that expressed GFAP; the expression of Pax6, Ascl1, PSA-NCAM or NeuroD1 was undetectable or did not change significantly. Expression of rhodopsin was not detectable in control or after exposure of the cultures with retinal conditioned media. By contrast, 44% of DPSCs exposed to conditioned media from damaged retinas were immunopositive to this protein. This response could not be reproduced when conditioned media from Müller-enriched primary cultures was used. Finally, quantitative RT-PCR was performed to compare the relative expression of glial cell-derived neurotrophic factor (GDNF), nerve growth factor (NGF), ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) in DPSC co-cultured with retinal organotypic explants, where BDNF mRNA expression was significantly upregulated in retinal-exposed cultures. Our data demonstrate that DPSC cultures respond to cues from the rat retina and differentiate to express retinal neuronal markers.
Assuntos
Células-Tronco Adultas/fisiologia , Diferenciação Celular/fisiologia , Polpa Dentária/fisiologia , Retina/metabolismo , Rodopsina/metabolismo , Adulto , Células-Tronco Adultas/citologia , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Técnicas de Cultura de Células , Técnicas de Cocultura , Meios de Cultivo Condicionados , Polpa Dentária/citologia , Células Ependimogliais/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Humanos , Fatores de Crescimento Neural/metabolismo , Molécula L1 de Adesão de Célula Nervosa/metabolismo , RNA Mensageiro/metabolismo , Ratos Long-Evans , Retina/lesões , Ácidos Siálicos/metabolismo , Técnicas de Cultura de Tecidos , Adulto JovemRESUMO
The authors study the possible involvement of retrovirus in Sjögren's syndrome. They report a preliminary study of 20 French and 13 Ecuadorian patients with a primary Sjögren syndrome. A previous epidemiologic study showed a HTLV1 seroprevalence going from 0.04 to 6% on different regions of Ecuador. The results of this study show the presence of anti-HTLV1 antibodies only in 2 Ecuadorian patients and does not allow a final conclusion of the role of HTLV1 virus. Nevertheless other studies continue on the serie using minor salivary gland specimens obtained by biopsy. Recent publications and the notion of an "endogen" retrovirus will may be lighten a new day in this research.
Assuntos
Vírus Linfotrópico T Tipo 1 Humano , Síndrome de Sjogren/virologia , Equador , França , Anticorpos Anti-HTLV-I/sangue , Vírus Linfotrópico T Tipo 1 Humano/imunologia , Vírus Linfotrópico T Tipo 1 Humano/isolamento & purificação , Humanos , Síndrome de Sjogren/epidemiologiaRESUMO
The prevalence of HHV-6 IgG was studied in 11 different countries across several continents: Morocco, Burkina-Faso, Congo, Ivory Coast, Mali, Niger, Senegal, Togo, Ecuador, Martinique, and France. The study group consisted of 550 pregnant women, representative of the general adult population in each country. Antibodies were detected by immunofluorescence assay on HSB-2 cells infected with HHV-6. Each serum was tested at nine dilutions (1:20 to 1:5,120), sera greater than or equal to 20 being considered positive. For the negative antigen control, we used mock-infected HSB-2 cells. Great differences were seen between separate areas: Morocco showed both low prevalence (20%) and a low geometric mean titer (12), whereas sub-Saharan Africa displayed high prevalences (60% to 90%) and variable geometric mean titers (34 to 229). This study revealed a prevalence of 92% for Ecuador, significantly higher than the prevalence for Martinique (50%), yet both countries had very low antibody titers compared with those found in Africa. The prevalence in France (76%) was similar to previous results from other European countries.