Cell Surface Accumulation of Intracellular Leucine Proline-Enriched Proteoglycan 1 Enhances Odontogenic Potential of Human Dental Pulp Stem Cells.

Primary dental pulp cells can be differentiated into odontoblast-like cells, which are responsible for dentin formation and mineralization. Successful differentiation of primary dental pulp cells can be verified using a few markers. However, odontoblast-specific cell surface markers have not been fully studied yet. LEucine PRoline-Enriched Proteoglycan 1 (LEPRE1) is a basement membrane-associated proteoglycan. LEPRE1 protein levels are increased during odontoblastic differentiation of human dental pulp cells (hDPCs). Intracellular and cell surface accumulation of this protein completely disappeared during dentin maturation and mineralization. Cell surface binding of an anti-LEPRE1 monoclonal antibody that could recognize an extracellular region was gradually increased in the odontoblastic stage. Overexpression and knockdown experiments showed that accumulation of intracellular LEPRE1 could lead to inefficient odontoblastic differentiation and that the movement of LEPRE1 from intracellular region to the cell surface was required for odontoblastic differentiation. Indeed, when LEPRE1 already located on the cell surface was blocked by the anti-LEPRE1 monoclonal antibody, odontoblastic differentiation of hDPCs was inhibited. In this study, we looked at other aspects of LEPRE1 function as a cell surface molecule rather than its known intracellular hydroxylase activity. Our results indicate that this protein has potential as a specific cell surface marker in odontoblastic differentiation.

3D Spheroid Formation Using BMP-Loaded Microparticles Enhances Odontoblastic Differentiation of Human Dental Pulp Stem Cells.

Human dental pulp stem cells (hDPSCs) are the primary cells responsible for dentin regeneration. Typically, in order to allow for odontoblastic differentiation, hDPSCs are cultured over weeks with differentiation-inducing factors in a typical monolayered culture. However, monolayered cultures have significant drawbacks including inconsistent differentiation efficiency, require a higher BMP concentration than should be necessary, and require periodic treatment with BMPs for weeks to see results. To solve these problems, we developed a 3D-cell spheroid culture system for odontoblastic differentiation using microparticles with leaf-stacked structure (LSS), which allow for the sustained release of BMPs and adequate supply of oxygen in cell spheroids. BMPs were continuously released and maintained an effective concentration over 37 days. hDPSCs in the spheroid maintained their viability for 5 weeks, and the odontoblastic differentiation efficiency was increased significantly compared to monolayered cells. Finally, dentin-related features were detected in the spheroids containing BMPs-loaded microparticles after 5 weeks, suggesting that these hDPSC-LSS spheroids might be useful for dentin tissue regeneration.

Correlation Between Mechanography and Clinical Parameters at Six Months After Hip Fracture Surgery.

OBJECTIVE: To investigate the correlation between mechanography and clinical parameters in older people at 3 and 6 months after hip fracture surgery. METHODS: A longitudinal follow-up study was conducted in university hospitals with 38 patients at 3 months and 29 patients at 6 months after hip fracture surgery. Subjects 65 years and older completed measurements on the Berg Balance Scale (BBS), Functional Ambulation Category (FAC), walking ability by Koval, Korean version of the fatigue, resistance, ambulation, illnesses, and loss of weight (K-FRAIL) scale, and hand grip strength. The Romberg test with center of foot pressure (COP), chair rise test (CRT), and maximal power (W/kg) were conducted using the Leonardo Mechanograph. RESULTS: COP area and pathway length were correlated with BBS at 3 and 6 months. Change in BBS was correlated with change in COP area, but not with change in COP length. COP area and pathway length were correlated with K-FRAIL at 3 months after hip fracture surgery. The same COP variables showed correlations with FAC and walking ability by Koval at 6 months after surgery. Maximal power during CRT had correlation with chair rise time but not with other clinical parameters. CONCLUSION: The study revealed correlations between mechanography and clinical parameters in older people at 3 and 6 months after hip fracture surgery. Both the clinical assessment and objective test with mechanography may be required for the quantitative and sensitive measurement of postural balance and lower limb muscle power.

Association Between Walking and Low Back Pain in the Korean Population: A Cross-Sectional Study.

OBJECTIVE: To investigate if walking is independently associated with low back pain (LBP) in the general population. METHODS: This cross-sectional study used public data from the Fourth and Fifth Korean National Health and Nutrition Examination Survey. Subjects included 5,982 community-dwelling adults aged ≥50 years. Presence of current LBP was defined as LBP for 1 month or more in the past 3 months. Walking was measured as total walking duration for the past week and subjects were divided into four quartiles. Independent effect of walking on LBP was determined using odds ratios (OR) adjusted for age, sex, osteoporosis, depression or anxiety, and radiographic lumbar spondylosis. RESULTS: Prevalence of LBP was 26.4% in this population. Older people and women had higher prevalence of current LBP. Prevalence of obesity and osteoporosis was higher in subjects with current LBP and quality of life was poorer in subjects with current LBP. Adjusted logistic regression model revealed that older age (OR, 1.655; p=0.018), female sex (OR, 2.578; p<0.001), radiographic lumbar spondylosis (OR, 2.728; p<0.001), depression or anxiety (OR, 5.409; p<0.001), and presence of osteoporosis (OR, 1.467; p=0.002) were positively associated with current LBP. Walking decreased prevalence of current LBP proportionally (2nd quartile OR, 0.795; 3rd quartile OR, 0.770; and 4th quartile OR, 0.686 compared with the 1st quartile of walking). CONCLUSION: Walking was negatively associated with LBP. Further studies are needed to reveal causal relationship of this phenomenon.