Hyperlipidemia compromises homing efficiency of systemically transplanted BMSCs and inhibits bone regeneration.

PURPOSE: Mesenchymal stem cells (MSCs) can selectively home to bone defects and play an essential role in promoting bone regeneration. As an adverse effect factor for bone metabolism, hyperlipidemia significantly impairs bone regeneration. In this study, bone marrow stromal cells (BMSCs) were systemically transplanted into a hyperlipidemic mouse model to explore the effect of hyperlipidemia on stem cell recruitment and bone regeneration. METHODS: Hyperlipidemia was established in ApoE-/- mice (on C57BL/6J background) fed with a high fat diet (HFD) for five weeks. C57BL/6 mice fed with the same diet served as controls. BMSCs labeled with the green fluorescent protein (GFP) were then injected via the tail vein and bone defects were created in the mandibles. The animals were sacrificed at weeks 1, 2 and 4 after surgery, and the fate of the transplanted BMSCs was monitored with a fluorescence microscope and immunohistochemical analysis. After hematoxylin and eosin (HE) staining and Masson's Trichrome (MT) staining, histomorphometric analysis was performed to evaluate bone regeneration. RESULTS: In both groups transplanted with BMSCs, the number of GFP-positive BMSCs detected in the bone defects reached its peak at 1 week after surgery and was decreased thereafter. However, at all time points, less GFP+ cells were detected in the ApoE-/- mice than in the corresponding control mice. BMSCs transplantation significantly enhanced new bone formation, but to a lesser degree in the ApoE-/- mice when compared with the control mice. CONCLUSIONS: Hyperlipidemia compromises homing efficiency of systemically transplanted BMSCs and inhibits bone regeneration.

Osteopromotive activity of a novel pyrazole carboxamide derivative.

AIMS: To investigate the effect of 1-(4-(tert-butyl)benzyl)-N-(4-methoxyphenyl)-3-phenyl-1H-pyrazole-5-carboxamide (Pyr-C) on the proliferation and osteogenic differentiation of MC3T3-E1 cells. MATERIALS & METHODS: MTT and BrdU incorporation assay were used to determine cell survival and proliferation. The gene expression levels of osteogenic markers were determined using real-time PCR and ALP activity was detected. Western-blot analysis was used to determine the protein expression of BSP and OPN. The long-term effect of Pyr-C on mineralization deposition was measured by Alizarin Red Staining. RESULTS: Pyr-C inhibited cell proliferation and increased ALP activity. Gene expression of ALP, BSP, OCN, Runx2, and Osterix was up-regulated in Pyr-C-induced group. Pyr-C increased the protein expression of BSP at day 7, 14 and 21, and OPN at day 14, 21 and 28. Meanwhile, Pyr-C enhanced the mineral deposition. CONCLUSION: Pyr-C inhibits proliferation and stimulates osteogenic differentiation of MC3T3-E1 cells.

[Biological effects of phenytoin on cultured human periodontal ligament fibroblasts in vitro].

OBJECTIVE: To study the biological effects of phenytoin (PHT) on cultured human periodontal ligament fibroblasts (hPDLF), and explore the possibility of its accelerating periodontal regeneration. METHODS: Increasing concentrations of PHT (1, 5, 20, 100, 500, 2 500 mg/L) were added into the medium of the fourth passage of cultured hPDLF, respectively. After co-incubated for 3 days, cell proliferation activity, the total amount of protein and alkaline phosphatase (ALP) activity were detected. Mineralized sodium and PHT (20, 100, 500 mg/L) were added into the medium of the fourth passage hPDLF. After co-incubated, the mineralized nodules formation were detected by Von Kossa staining. The third passage hPDLF were stimulated by PHT (20, 100 mg/L), bone morphogenetic protein-2 (BMP-2) concentration was analyzed by enzyme linked immunosorbent sandwich assay (ELISA). RESULTS: At the concentration of 20 or 100 mg/L, PHT significantly enhanced the proliferating activity and ALP activity of hPDLF (P<0.01). PHT at 100 mg/L could increase protein synthesis of hPDLF (P<0.05). The capability of mineralization and BMP-2 expression of hPDLF were increased significantly (P<0.01) in 100 mg/L group when compared with that in the control group. However, higher concentration (2 500 mg/L) not only changed cell morphology, but also significantly inhibited cell activity. CONCLUSION: The results suggested that proper doses of PHT could promote proliferation and biosynthesis and also enhance osteogenesis by increasing the differentiation, mineralization and BMP-2 expression of hPDLF while higher concentrations of PHT had cytotoxic effect.