Background and Objectives: Chronic periodontitis can lead to alveolar bone resorption and eventually tooth loss. Stem cells from exfoliated deciduous teeth (SHED) are appropriate bone regeneration seed cells. To track the survival, migration, and differentiation of the transplanted SHED, we used super paramagnetic iron oxide particles (SPIO) Molday ION Rhodamine-B (MIRB) to label and monitor the transplanted cells while repairing periodontal bone defects. Methods: and Results: We determined an appropriate dose of MIRB for labeling SHED by examining the growth and osteogenic differentiation of labeled SHED. Finally, SHED was labeled with 25 μg Fe/ml MIRB before being transplanted into rats. Magnetic resonance imaging was used to track SHED survival and migration in vivo due to a low-intensity signal artifact caused by MIRB. HE and immunohistochemical analyses revealed that both MIRB-labeled and unlabeled SHED could promote periodontal bone regeneration. The colocalization of hNUC and MIRB demonstrated that SHED transplanted into rats could survive in vivo. Furthermore, some MIRB-positive cells expressed the osteoblast and osteocyte markers OCN and DMP1, respectively. Enzyme-linked immunosorbent assay revealed that SHED could secrete protein factors, such as IGF-1, OCN, ALP, IL-4, VEGF, and bFGF, which promote bone regeneration. Immunofluorescence staining revealed that the transplanted SHED was surrounded by a large number of host-derived Runx2- and Col II-positive cells that played important roles in the bone healing process. Conclusions SHED could promote periodontal bone regeneration in rats, and the survival of SHED could be tracked in vivo by labeling them with MIRB. SHED are likely to promote bone healing through both direct differentiation and paracrine mechanisms.

OBJECTIVETo explore the role of sphingomyedlin phosphodiesterase 1 (SMPD1) gene mutations in the pathogenesis of Parkinson's disease (PD).

METHODSFor 110 Chinese patients with PD, all exons of the SMPD1 gene were sequenced, and the results were compared with reference sequence from GenBank to identify possible mutations.

RESULTSA novel heterozygous mutation Ex2:c.677C>A/p.P226Q (likely pathogenic) was identified in a patient, which resulted in substitution of Glutamic acid by Proline at position 226. In addition, two known single nucleotide polymorphisms (SNPs) Ex1:c.107T>C/p.V36A (benign) and Ex6:c.1522G>A/p.G508R (benign), and three previously reported SMPD1 mutations Ex2:c.T371T>G/p.L124R (uncertain significance), Ex2:c.636T>C/P.(=)(benign) and Ex6:c.1598C>T/p.P533L (uncertain significance) were identified. The novel p.P226Q mutation and p.P533L mutation were predicted to have a possibly damaging effect on the structure and function of SMPD1 protein, which in turn may lead to PD.

CONCLUSIONThe mutation rate of the SMPD1 gene was 3.64% among Chinese PD patients. Genetic variants of SMPD1 may increase the risk of PD.