[Study on dental pulp stem cells from patients with hypophosphatasia].
OBJECTIVE
To find out whether the dentin formation of hypophosphatasia children is affected; to study the biological difference of cultured human dental pulp cells from deciduous teeth between hypophosphatasia and normal healthy children.


METHODS
Anterior deciduous teeth were collected from hypophosphatasia (experiment group) and normal healthy children (control group) respectively. Grounding sections of the affected and healthy deciduous teeth were made to observe their roots; the dental pulp cells were separated and cultured. The characteristics of cell proliferation, differentiation and calcification were studied and compared between the two groups of children. MTT assay was performed to study the growth curves of the cells; RT-PCR was performed to evaluate the expression of tissue nonspecific alkaline phosphatase (TNSALP) at different stages; von Kosssa staining was used to test formed calcification nodules after 3 weeks of induction.


RESULTS
From the grounding sections, the root surface of the experiment group was not smooth with absorbed areas, cementum was absent. For proliferation activity and the expression of TNSALP, the dental pulp cells from experiment group was obviously lower than control group. Calcified nodules could be seen in both groups, but the nodules were less and the sizes were smaller in experiment group than in control group.


CONCLUSIONS
In hypophosphatasia patients, not only the cementum but also the dentin were affected. The proliferation, TNSALP expression and calcification capability of the dental pulp cells were influenced in hypophosphatasia patients, and this may be related to the tooth calcification defect.
Li
Jing
J
Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, Beijing 100081, China.
Liu
He
H
Ge
Li-hong
LH
D000469:Alkaline Phosphatase / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D003739:Dental Cementum / Q000378:metabolism; D003782:Dental Pulp / Q000473:pathology*; D003804:Dentin / Q000378:metabolism; D005260:Female; D006801:Humans; D007014:Hypophosphatasia / Q000473:pathology*; D008297:Male; D014074:Tooth Calcification / Q000502:physiology*; D014094:Tooth, Deciduous / Q000473:pathology
D000469:Alkaline Phosphatase