We have previously reported that repeated treatment of human periodontal ligament cells and murine pre-osteoblast MC3T3-E1 cells with transforming growth factor-beta 1 (TGF-β1) inhibited their ...osteoblastic differentiation because of decreased insulin-like growth factor-1 (IGF-1) secretion. We also found that IGF-1/PI3K signaling plays an important role in osteoblast differentiation induced by TGF-β1 treatment; however, the downstream signaling controlling this remains unknown. The aim of this current study is to investigate whether Akt activation is required for osteoblast differentiation.
MC3T3-E1 cells were cultured in osteoblast differentiation medium (OBM) with or without 0.1 ng/mL TGF-β1. OBM containing TGF-β1 was changed every 12 h to provide repeated TGF-β1 administration. MC3T3-E1 cells were infected with retroviral vectors expressing constitutively active (CA) or dominant-negative (DN)-Akt. Alkaline phosphatase (ALP) activity and osteoblastic marker mRNA levels were substantially decreased by repeated TGF-β1 treatment compared with a single TGF-β1 treatment. However, expression of CA-Akt restored ALP activity following TGF-β1 treatment. Surprisingly, ALP activity increased following multiple TGF-β1 treatments as the number of administrations of TGF-β1 increased. Activation of Akt significantly enhanced expression of osteocalcin, but TGF-β1 treatment inhibited this. Mineralization of MC3T3-E1 cells was markedly enhanced by CA-Akt expression under all medium conditions. Exogenous IGF-1 restored the down-regulation of osteoblast-related gene expression by repeated TGF-β1 administration. However, in cells expressing DN-Akt, these levels remained inhibited regardless of IGF-1 treatment. These findings indicate that Akt activation is required for the early phase of osteoblast differentiation of MC3T3-E1 cells induced by TGF-β1. However, Akt activation is insufficient to reverse the inhibitory effects of TGF-β1 in the late stages of osteoblast differentiation.
TGF-β1 could be an inducer or an inhibitor of osteoblastic differentiation of MC3T3-E1 cells depending on the state of Akt phosphorylation. Our results indicate that Akt is the molecular switch for TGF-β1-induced osteoblastic differentiation of MC3T3-E1 cells.
Cleidocranial dysplasia (CCD) is a hereditary disorder associated with skeletal dysplasia and dental abnormalities. CCD arises from heterozygous loss of function mutations in the Runt-related ...transcription factor 2 (RUNX2) gene. Osteoporosis is often observed in CCD patients and conventional vitamin D supplementation is recommended. However, sufficient evidences have not been presented yet. This study investigated the role of RUNX2 in osteoblastic differentiation and sought to identify potential target genes for the treatment of osteoporosis associated with CCD, using induced pluripotent stem cell (iPSC) technology. We successfully established
Runx2
−/−
, Runx2
+/−
and wild-type miPSCs from litter-matched mice and found poor
Vdr
expression in
Runx2
−/−
cells. Significant down-regulation of osteoblastic differentiation in
Runx2
−/−
miPSCs was observed. Gene expression array revealed unexpected results such as remarkable increase of
Rankl
expression and decrease of
Vdr
in
Runx2
−/−
cells. Insufficient response to vitamin D in
Runx2
−/−
cells was also observed. Our results suggest that RUNX2 functions as a regulator of
Rankl
and
Vdr
and thereby controls bone density. These findings also suggest that conventional vitamin D supplementation may not be as effective as previously expected, in the treatment of osteoporosis associated with CCD, and that inhibiting RANKL function might be worth considering as an alternative treatment strategy.
The aim of this study was to evaluate longitudinal outcomes of recombinant human fibroblast growth factor (rhFGF)-2 plus deproteinized bovine bone mineral (DBBM) therapy in comparison with rhFGF-2 ...alone for treating periodontal intrabony defects. This study describes 4-year follow-up outcomes of the original randomized controlled trial. Intrabony defects in periodontitis patients were treated with rhFGF-2 (control) or rhFGF-2 plus DBBM (test). Clinical, radiographic, and patient-reported outcome (PRO) measures were used to evaluate the outcomes. Thirty-two sites were able to be followed up. At 4 years postoperatively, clinical attachment level (CAL) gains in the test and control groups were 3.5 ± 1.4 mm and 2.7 ± 1.4 mm, respectively, showing significant improvement from preoperative values but no difference between groups. Both groups showed an increase in radiographic bone fill (RBF) over time. At 4 years, the mean value for RBF in the test group (62%) was significantly greater than that in the control group (42%). In 1–2-wall defects, the test treatment yielded significantly greater RBF than the control treatment. No significant difference in PRO scores was noted between the groups. Although no significant difference in CAL gain was found between the groups at the 4-year follow-up, the combination treatment significantly enhanced RBF. Favorable clinical, radiographic outcomes, and PRO in both groups can be maintained for at least 4 years.
To date, enamel matrix derivative (EMD) has been considered to be one of the few biomaterials for clinical use capable of demonstrating true periodontal regeneration. The aim of this two-center ...prospective clinical study was to evaluate 2-year outcome of periodontal regenerative therapy using EMD in the treatment of intrabony defects, performed as an 'advanced medical treatment' under the national healthcare system in Japan.
Patients with chronic periodontitis who have completed initial periodontal therapy at either of the two dental school clinics were enrolled. Each contributed at least one intrabony defect of ≥3 mm in depth. During surgery, EMD was applied to the defect following debridement. Twenty-two participants (mean age 55.2 years old, 9 men and 13 women) completed 2-year reevaluation, and a total of 42 defects were subjected to data analysis. Mean gains in clinical attachment level (CAL) at 1 and 2 years were 2.9 mm (38% of baseline CAL) and 3.1 mm (41%), respectively, both showing a significant improvement from baseline. There was also a significant reduction in probing depth (PD): mean reductions at 1 and 2 years were 3.2 and 3.3 mm, respectively. There was a progressive improvement in the mean percentages of bone fill from 26% at 1 year to 36% at 2 years. No significant difference in CAL gain at 2 years was found between 3-wall bone defects and other defect types combined. In multiple regression analysis, the baseline PD was significantly associated with CAL gain at 2 years. In this population of patients, the treatment of intrabony defects with EMD yielded clinically favorable outcomes, as assessed by periodontal and radiographical parameters, over a period of 2 years.
This report describes a case of generalized chronic periodontitis requiring periodontal treatment including surgery. The patient was a 64-year-old man who visited the Tokyo Dental College Suidobashi ...Hospital with the chief complaint of pain in tooth #27. An initial examination revealed a probing depth (PD) of ≥4 mm at 38.2% of sites and bleeding on probing at 26.5% of sites. Radiographic examination revealed vertical bone resorption in # 27, 34, and 47, and horizontal resorption in other areas. Based on a clinical diagnosis of severe chronic periodontitis, initial periodontal therapy consisting of plaque control, scaling and root planing was performed. Both #27 and #47 were extracted due to bone resorption extending as far as the root apex. After initial periodontal therapy, sites with a PD of ≥4 mm were observed at 16.7% of sites. Furcation involvement was observed in #16, 17, 36, and 37. The need and options for periodontal surgery based on these findings were explained to the patient. Open flap debridement was implemented for #16, 17, 31, 34, 36, and 37 to reduce periodontal pockets. After reevaluation, the patient was placed on supportive periodontal therapy. The results of the periodontal examination at first visit revealed a periodontal pocket depth of 6 mm and 7 mm in #16 and 17, respectively, and class II furcation involvement in both. Periodontal therapy with open flap debridement resulted in an improvement in horizontal bone resorption where there was class II furcation involvement. This improvement has been adequately maintained over a 4-year period.
We report a case of generalized chronic periodontitis requiring periodontal regenerative therapy. The patient was a 53-year-old woman who presented with the chief complaint of gingival swelling. An ...initial examination revealed 31.5% of sites with a probing depth of ≥4 mm and 46.3% with bleeding on probing. Radiographic examination showed vertical bone resorption in tooth #33. Horizontal adsorption was also observed in other areas. Based on a clinical diagnosis of severe generalized chronic periodontitis, initial periodontal therapy consisting of plaque control, scaling and root planing, occlusal adjustment, caries treatment, and splint placement was performed. After re-evaluation, surgical periodontal treatment was performed at selected sites. Periodontal regeneration therapy with recombinant human fibroblast growth factor (rhFGF)-2 was performed at #33. Two other sites (#14, 15), which had residual periodontal pockets, were treated by open-flap debridement. After re-evaluation, the patient was placed on a maintenance program. Periodontal regenerative therapy with rhFGF-2 resulted in an improvement in angular bone resorption, which has been properly maintained for 2 years. Continued care is needed to maintain stable periodontal conditions.
Background/Objectives
PTH plays an important role in bone remodeling, and different actions have been reported depending on its administration method. iPSCs are promising as a cell source for ...regeneration of periodontal tissue due to their ability of proliferation and pluripotency. However, the effects of PTH on iPSCs remain mostly unknown. The purpose of this study was to investigate in vitro effects of parathyroid hormone (PTH) on osteoblastic differentiation of induced pluripotent stem cells (iPSCs) in a 3D culture model.
Materials and Methods
Following embryoid body (EB) induction from mouse iPSCs (miPSCs), dissociated cells (miPS‐EB‐derived cells) were seeded onto atelocollagen sponge (ACS) in osteoblast differentiation medium (OBM). Cell‐ACS constructs were divided into three groups: continuous treatment with human recombinant PTH (1‐34) (PTH‐C), intermittent PTH treatment (PTH‐I) or OBM control. To confirm the expression of PTH receptor‐1(PTH1R), the expression of Pth1r and cAMP production over time were assessed. Real‐time PCR was used to assess the expression of genes encoding osterix (Sp7), runt‐related transcription factor 2 (Runx2), collagen type 1 (Col1a1), and osteocalcin (Bglap) at different time points. Mineralization was assessed by von Kossa staining. Histochemical staining was used to analyze alkaline phosphatase (ALP) activity, and immunolocalization of SP7 and BGLAP was analyzed by confocal laser scanning microscopy (CLSM).
Results
On days 7 and 14, expression of the Pth1r in miPS‐EB‐derived cells was increased in all groups. Production of cAMP, the second messenger of the PTH1R, tended to increase in the PTH‐I group compared with PTH‐C group on day 14. Expression of Col1a1 in the PTH‐I group on day 14 was significantly higher than other groups. There was a time‐dependent increase in the expression of Sp7 in all groups. On day 14, the expression level of Sp7 in the PTH‐I group was significantly higher than other groups. In von Kossa staining, the PTH‐I group showed higher level of staining compared with other groups on day 14, whereas the level was slightly attenuated in the PTH‐C group. In histochemical staining, ALP‐positive cells were significantly increased in the PTH‐I group compared with other groups on day 14. In CLSM analysis, the numbers of SP7‐ and BGLAP‐positive cells showed a gradual increase over time, and on day 14, a significantly greater SP7 expression was observed in the PTH‐I group than other groups.
Conclusion
These results suggested that the intermittent PTH treatment promotes osteoblastic differentiation and mineralization of miPSCs in the ACS scaffold.
Here, we report a case of chronic periodontitis requiring periodontal regenerative therapy. The patient was a 73-year-old man who visited Tokyo Dental College Suidobashi Hospital with the chief ...complaint of gingival swelling and mobile tooth in the mandibular incisor region. An initial examination revealed that 33% of sites had a probing depth (PD) of≥4 mm and 27% bleeding on probing. Radiographic examination revealed bone resorption extending as far as the root apex in #32 and 47, vertical bone resorption in #37, and horizontal resorption in other regions. Based on a clinical diagnosis of moderate chronic periodontitis, initial periodontal therapy was carried out followed by periodontal surgery. The patient's oral health-related quality of life was also assessed at the time of each periodontal assessment. Surgical periodontal therapy was subsequently performed at selected sites. Periodontal regenerative therapy using enamel matrix derivative was performed on #37. Other sites with a PD of ≥4 mm were treated with open flap debridement, and scaling and root planing. Following reevaluation, the patient was placed on supportive periodontal therapy. The patient's periodontal condition has remained stable over a 3-year 6-month period. The patient's oral health-related quality of life showed a marked improvement after periodontal therapy.
Aim
To compare outcomes of rhFGF‐2 + DBBM therapy with rhFGF‐2 alone in the treatment of intrabony defects. This study provides 2‐year follow‐up results from the previous randomized controlled trial.
...Materials and Methods
Defects were randomly allocated to receive rhFGF‐2 + DBBM (test) or rhFGF‐2 (control). Treated sites were re‐evaluated at 2 years postoperatively, using original clinical and patient‐centred measures.
Results
Thirty‐eight sites were available for re‐evaluation. At 2 years, both groups showed a significant improvement in clinical attachment level (CAL) from baseline. A gain in CAL of 3.4 ± 1.3 mm in the test group and 3.1 ± 1.5 mm in the control group was found. No significant inter‐group difference was noted. Both groups showed a progressive increase in radiographic bone fill (RBF). The test treatment yielded greater RBF (56%) compared with the control group (41%). The control treatment performed better in contained defects in terms of CAL and RBF. There was no significant difference in patient‐reported outcomes between groups.
Conclusions
At 2‐year follow‐up, the test and cotrol treatments were similarly effective in improving CAL, whereas the test treatment achieved a significantly greater RBF. In both treatments, favourable clinical, radiographic, and patient‐reported outcomes can be sustained for at least 2 years.
Trial registration
The University Hospital Medical Information Network‐Clinical Trials Registry (UMIN‐CTR) 000025257.
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