PGP9.5-immunoreactive nerve fibers in a deciduous second molar and succeeding permanent second molar in a 5-month-old cat (a).

<p>b-e: Higher magnification views of boxed areas in a. b: In the periodontal ligament under the resorbing root of deciduous second molar, PGP9.5-immunoreactive thick nerve fibers are detected as having a dot-like appearance. c: Many PGP9.5-immunoreactive nerve fibers are randomly distributed in the cervical area of the periodontal ligament of the permanent premolar. d: At the apical part of the distal side of the periodontal ligament of the distal root of the permanent second premolar, thick nerve fibers and thin varicose nerve fibers are running coronally. e: In the furcation area of the permanent premolar, PGP9.5-immunopositive thick nerve fibers (arrowheads) and thin nerve fibers with varicosity (arrows) are found. AB: alveolar bone, D1: dentin of primary teeth, D2: dentin in permanent teeth, P: pulp. Scale bars: 200 μm in a, and 50 μm in b, which is applicable to c-e.</p

PGP9.5-immunoreactivities in the periodontal ligament of the lower second deciduous molar of the 2-month-old cat.

<p>a; Low-powered image of the root apex. A few nerve fibers are found in the periodontal ligament (PDL). C; cementum, AB; alveolar bone. b; High-powered image of the boxed area in a. Thick nerve fibers run along the periodontal ligament. They are less ramified and do not terminate in the cementum. c-e: Double-labeling for PGP9.5 (c) and S100 (d), and merged image (e) in the periodontal ligament in a 2-month-old lower second deciduous molar. Rounded S100-positive cells (arrowheads in d, e) are associated with PGP9.5-immunoreactive nerve fibers. Scale bars: 100 μm in a, 50 μm in b, 20 μm in e (also applied for c and d)</p

PGP9.5 immunoreactivity in the periodontal ligament of the permanent premolar (a) and molar (b) in a 12-month-old cat.

<p>Many thick PGP9.5-immunoreactive thick nerve terminals are observed. They are less expanded. C: cementum Scale bars: 50 μm</p

Double-labeling images for PGP9.5 (a, d) and S100 (b) or S100β(e), and merged images (c, f) in the apical periodontal ligament of deciduous second molar of 2-month-old cat (2mo; a-c) and cervical portion of erupting permanent second premolar of 5-month-old cat (5mo; d-f).

<p>a-c: PGP 9.5-immunoreactive nerve fibers (a, c) accompanying S-100 immunoreactive structures (b, c) are observed without interruption in the ligament of 2-month-old-cat. d-f: PGP9.5-immunoreactive nerve fibers show a dot-like appearance (d, f), while continuity of S100 structures is recognized (e, f) in 5-month-old cat. Scale bar: 50 μm.</p

Radiographic images of the mandibles in 2-month-old (a), 5-month-old (b), and 12-month-old (c) cats.

<p>m1: first deciduous molar, m2: second deciduous molar, M1: first permanent molar, P1: first permanent premolar, P2: second permanent premolar. Scale bar = 5 mm</p

Schematic drawing for quantitative analysis.

<p>The percentage of PGP 9.5 immunoreactive areas was measured in the cervical (C), middle (M) and apical (A) portions of distal side of distal root of deciduous second molar (m₂) of the 2-month-old cat and permanent second premolar (P₂) of the 5-month-old cat, and mesial side of mesial root of permanent first molar (M₁) of the 5- and 12-month-old cats at the length of 800 μm (dotted area).</p

TGF-Beta Negatively Regulates the BMP2-Dependent Early Commitment of Periodontal Ligament Cells into Hard Tissue Forming Cells

<div><p>Transforming growth factor beta (TGF-β) is a multi-functional growth factor expressed in many tissues and organs. Genetic animal models have revealed the critical functions of TGF-β in craniofacial development, including the teeth and periodontal tissue. However, the physiological function of TGF-β in the periodontal ligament (PDL) has not been fully elucidated. In this study, we examined the roles of TGF-β in the cytodifferentiation of PDL cells using a TGF-β receptor kinase inhibitor, SB431542. Mouse PDL cell clones (MPDL22) were cultured in calcification-inducing medium with or without SB431542 in the presence or absence of various growth factors, such as bone morphogenetic protein (BMP)-2, TGF-β and fibroblast growth factor (FGF)-2. SB431542 dramatically enhanced the BMP-2-dependent calcification of MPDL22 cells and accelerated the expression of ossification genes <i>alkaline phosphatase</i> (<i>ALPase</i>) and <i>Runt-related transcription factor</i> (<i>Runx</i>) <i>2</i> during early osteoblastic differentiation. SB431542 did not promote MPDL22 calcification without BMP-2 stimulation. The cell growth rate and collagen synthesis during the late stage of MPDL22 culture were retarded by SB431542. Quantitative reverse transcription polymerase chain reaction analysis revealed that the expressions of <i>Smurf1</i> and <i>Smad6</i>, which are negative feedback components in the TGF-β/BMP signaling pathway, were downregulated in MPDL22 cells with SB431542 treatment. These results suggest that an endogenous signal from TGF-β negatively regulates the early commitment and cytodifferentiation of PDL cells into hard tissue-forming cells. A synthetic drug that regulates endogenous TGF-β signals may be efficacious for developing periodontal regenerative therapies.</p></div

Examination of the Relationship between Oral Health and Arterial Sclerosis without Genetic Confounding through the Study of Older Japanese Twins

<div><p>Objective</p><p>Although researchers have recently demonstrated a relationship between oral health and arterial sclerosis, the genetic contribution to this relationship has been ignored even though genetic factors are expected to have some effect on various diseases. The aim of this study was to evaluate oral health as a significant risk factor related to arterial sclerosis after eliminating genetic confounding through study of older Japanese twins.</p><p>Subjects and Methods</p><p>Medical and dental surveys were conducted individually for 106 Japanese twin pairs over the age of 50 years. Maximal carotid intima-media thickness (IMT-Cmax) was measured as a surrogate marker of arterial sclerosis. IMT-Cmax > 1.0 mm was diagnosed as arterial sclerosis. All of the twins were examined for the number of remaining teeth, masticatory performance, and periodontal status. We evaluated each measurement related with IMT-Cmax and arterial sclerosis using generalized estimating equations analysis adjusted for potential risk factors. For non-smoking monozygotic twins, a regression analysis using a “between within” model was conducted to evaluate the relationship between IMT-Cmax and the number of teeth as the environmental factor controlling genetic and familial confounding.</p><p>Results</p><p>We examined 91 monozygotic and 15 dizygotic twin pairs (males: 42, females: 64) with a mean (± standard deviation) age of 67.4 ± 10.0 years. Out of all of the oral health-related measurements collected, only the number of teeth was significantly related to arterial sclerosis (odds ratio: 0.72, 95% confidence interval: 0.52-0.99 per five teeth). Regression analysis showed a significant association between the IMT-Cmax and the number of teeth as an environmental factor (<i>p</i> = 0.037).</p><p>Conclusions</p><p>Analysis of monozygotic twins older than 50 years of age showed that having fewer teeth could be a significant environmental factor related to arterial sclerosis, even after controlling for genetic and familial confounding.</p></div

Schematic illustration of the measurement of the distance between the cemento-enamel junction (CEJ) and the alveolar bone crest (ABC).

<p>Distance from the CEJ to the ABC was measured at four points indicated on the first molar to the third molar.</p

SB431542 treatment on ALP activity and expression of osteoblastic differentiation-related genes in MPDL22 cells.

<p>(A) MPDL22 cells were cultured in mineralization-inducing medium in the presence or absence of BMP-2 (50 ng/mL), TGF-β (4 ng/mL) and SB431542 (10 μM). MPDL22 cells were harvested at the indicated time points. ALPase activity was determined as described in the methods section. Activity in U/mg protein for the cell lysates is shown. **: p<0.01 vs BMP-2. (-): control; B: BMP-2; T: TGF-β; SB: SB431542. (B) Relative quantification of <i>ALP</i>, <i>Runx2</i>, <i>Osterix</i> and <i>BSP</i> mRNA expression levels was performed after 4 and 6 days of MPDL22 cell culture in the mineralization inducing medium with or without BMP-2 (50 ng/mL) and SB431542 (10 μM). D: AA plus β-GP; B: BMP-2; SB: SB431542.**: p<0.01 vs BMP-2; *: p<0.05 vs BMP-2.</p