Identification of genes preferentially expressed in periodontal ligament: Specific expression of a novel secreted protein, FDC-SP

Gene expression in human periodontal ligament (PDL) was examined by suppression subtractive hybridization to identify genes that are preferentially expressed in tissue compared to cultured PDL fibroblasts. The most enriched genes in a subtracted cDNA library are primarily genes for extracellular matrix components, types I and III collagen, lumican, periostin, and asporin, among others, whose expression conveys unique mechanical properties to the PDL. Also within this group is the gene for follicular dendritic cell secreted protein (FDC-SP), a small protein like statherin in saliva, not previously found in PDL. FDC-SP's presence in PDL was confirmed by in situ hybridization in mouse which also showed that it was definitely present in the parotid gland, but, surprisingly, not in the other salivary glands: submandibular and sublingual. Since only normal tissue was examined, these findings suggest that FDC-SP plays an important but previously unsuspected role within oral connective tissue.

Diagnostic potential of tear proteomic patterns in Sjögren's syndrome

Histological and functional changes of the lacrimal gland might be reflected in proteomic patterns in tear fluids. In this study, we carried out a determination of the disease biomarkers in tear fluid for Sjögren's syndrome (SS) and a performance of noninvasive diagnostic test based on the proteomic patterns. Thirty-one SS patients and 57 control subjects were enrolled to this study. Their details were 23 cases with primary SS, 8 with secondary SS, 14 with dry eyes, 22 with miscellaneous ocular diseases, and 21 of healthy volunteers. Protein profiling in tear fluids was identified by surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). Multiple protein changes were reproducibly detected in the primary SS group, including 10 potential novel biomarkers. Seven of the biomarkers (2094, 2743, 14191, 14702, 16429, 17453, 17792 m/z) were down-regulated and 3 biomarkers (3483, 4972, 10860 m/z) were up-regulated in primary SS group, comparing to the protein profiles of control subjects. When cutoff value of SS down-score was set less than 0.5, this result yielded 87% sensitivity and 100% specificity. The positive predictive value for this sample set was 100%. There was a significant inverse correlation between SS down-scores and epithelial damages of the ocular surface in primary SS patients. These findings support the potential of proteomic pattern technology in tear fluids as the noninvasive diagnostic test for primary SS.

Treatment of human class II furcation defects using connective tissue grafts, bioabsorbable membrane, and resorbable hydroxylapatite: a comparative study

OBJECTIVE

To evaluate clinical outcomes and assess digital subtraction radiographic changes after using bioabsorbable membrane (polyglycolic acid/polylactic acid--PGA/PLA) or a connective tissue graft (CTG) as a barrier, with or without resorbable hydroxylapatite (HA Resorb) in the treatment of mandibular class II furcations.

METHODS

Fifty furcations in twenty patients with chronic periodontitis were divided into five treatment groups: (I) PGA/PLA; (II) PGA/PLA and resorbable hydroxylapatite; (III) CTG; IV) CTG and resorbable hydroxylapatite; and (V) flap debridement alone (control). Vertical and horizontal probing depths, vertical probing attachment level, gingival recession and standardized periapical radiographs were obtained at baseline and at 3, 6 and 12 months post-operatively. At 12 months, the treated teeth were exposed by re-entry to verify clinical results.

RESULTS

All experimental groups (I, II, III and IV) showed statistically significant improvement in the clinical parameters and bone density as compared to the control group. However, no statistically significant differences were observed among any of the experimental groups. Percentages of complete furcation closure and sites still defined as class II furcations were, respectively, as follows: 40% and 20-30% for groups II and IV; 20% and 40% for groups I and III; 0% and 80% for control. Groups II and IV showed significant radiographic changes in bone gain at both 6 and 12 months, while groups I and III showed significant changes only at 12 months.

CONCLUSIONS

(1) Guided tissue regeneration (GTR) therapy with or without resorbable hydroxylapatite showed significantly favorable results clinically and radiographically compared to flap debridement alone. (2) GTR plus resorbable hydroxylapatite (groups II and IV) showed higher percentages of complete furcation closure and more bone gain than GTR alone (groups I and III). (3) CTG may be used as an alternative to PGA/PLA bioabsorbable membrane with comparable potential. (4) Digital subtraction radiography may give higher accuracy in assessing results of periodontal therapy.

Prostaglandin E2 (PGE2) downregulates interleukin (IL)-1alpha-induced IL-6 production via EP2/EP4 subtypes of PGE2 receptors in human periodontal ligament cells

OBJECTIVES

Prostaglandin E2 (PGE2) exerts its biological actions via EP receptors, which are divided into four subtypes, EP1, EP2, EP3 and EP4. In the present study, we examined whether PGE2 regulated interleukin (IL)-1alpha-induced IL-6 production in human periodontal ligament (PDL) cells and if so, which subtypes of PGE2 receptors were involved.

METHODS

PDL cells were stimulated with vehicle or IL-1alpha in the presence or absence of indomethacin (a cylooxygenase inhibitor), PGE2 or various EP agonists. IL-6 and PGE2 levels were measured by enzyme-linked immunosorbent assay. EP receptor mRNA expression was examined by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Indomethacin significantly enhanced IL-1alpha-induced IL-6 production by PDL cells, although it completely inhibited IL-1alpha-induced PGE2 production. Exogenous PGE2 significantly suppressed IL-1alpha-induced IL-6 production. Butaprost, a selective EP2 agonist, and ONO-AE1-329, a selective EP4 agonist, significantly inhibited IL-1alpha-induced IL-6 production, although 17-phenyl-omega-trinor PGE2, an EP1 agonist, and ONO-AP-324, an EP3 agonist, did not affect it. RT-PCR analysis showed that EP2 and EP4 mRNA was expressed in PDL cells.

CONCLUSIONS

We suggest that PGE2 downregulates IL-1alpha-induced IL-6 production via EP2/EP4 receptors in human PDL cells.

Elevated serum IgG titer and avidity to Actinobacillus actinomycetemcomitans serotype c in Japanese periodontitis patients

AIM

The purpose of this study was to characterize serum antibody responses to different serotypes of Actinobacillus actinomycetemcomitans strains in various forms of periodontitis and to determine whether any specific type of A. actinomycetemcomitans was associated with any specific form of periodontitis in a Japanese population.

METHODS

Sonicated whole cell and autoclaved serotype antigens of A. actinomycetemcomitans were used. Serum IgG titer and avidity to A. actinomycetemcomitans were measured by enzyme-linked immunoabsorbant assay (ELISA) and ammonium thiocyanate-dissociation ELISA, respectively, in 46 aggressive periodontitis patients (8 localized, 38 generalized), 28 chronic periodontitis patients, and 18 periodontally healthy subjects. The presence of A. actinomycetemcomitans in plaque and saliva samples was determined using polymerase chain reaction.

RESULTS

Generalized aggressive and chronic periodontitis patients exhibited significantly higher IgG titers than healthy subjects to both sonicated and autoclaved antigens of serotype c strains, while IgG titer to serotype b (Y4) was significantly higher in localized aggressive periodontitis patients compared to healthy subjects. No A. actinomycetemcomitans was detected in localized aggressive periodontitis patients. A. actinomycetemcomitans-positive patients exhibited significantly higher IgG titer and avidity to serotype c than A. actinomycetemcomitans-negative patients. In A. actinomycetemcomitans-positive patients, a significantly positive correlation was observed between antibody titer and avidity to serotype c. A. actinomycetemcomitans-positive patients with generalized aggressive periodontitis showed lower IgG avidities to serotype c than those with chronic periodontitis, though no statistically significant difference was found.

CONCLUSION

A. actinomycetemcomitans serotype c may play a significant role in chronic and generalized aggressive periodontitis, while A. actinomycetemcomitans serotype b may be associated with localized aggressive periodontitis in a Japanese population.

Prevotella multisaccharivorax sp. nov., isolated from human subgingival plaque

Six bacterial strains isolated from the human oral cavity, PPPA16, PPPA20T, PPPA24, PPPA31, EPPA6 and EPPA7, were characterized by determining phenotypic and biochemical features, cellular fatty acid profiles, menaquinone profiles and phylogenetic position based on 16S rRNA gene sequence analysis. 16S rRNA gene sequence analysis showed that the isolates represented the same species of the genus Prevotella. The strains were related to Prevotella dentalis with about 89 % similarity. In addition, the isolates were related to Prevotella sp. oral clone IDR-CEC-0032, which is a representative of the numerically dominant cluster VI in carious dentine lesions [Nadkarni et al. (2004). J Clin Microbiol 42, 5238–5244], with about 99 % similarity. The strains were obligately anaerobic, non-pigmenting, non-spore-forming, non-motile, Gram-negative rods. The isolates could be differentiated from other Prevotella species by d-mannitol, d-melezitose, d-sorbitol and d-trehalose fermentation in API 20A tests. The cellular fatty acid composition of strains PPPA16, PPPA20T, PPPA24, PPPA31, EPPA6 and EPPA7 was significantly different from that of other Prevotella species. Compared with other Prevotella species, only these six strains contained dimethyl acetals. The major menaquinones of the clinical isolates were MK-12 and MK-13, whereas the major menaquinones of other Prevotella species were MK-10 and MK-11. On the basis of these data, a novel Prevotella species, Prevotella multisaccharivorax sp. nov., is proposed, with PPPA20T (=JCM 12954T=DSM 17128T) as the type strain.

Cyclooxygenase-2-dependent prostaglandin (PG) E2 downregulates matrix metalloproteinase-3 production via EP2/EP4 subtypes of PGE2 receptors in human periodontal ligament cells stimulated with interleukin-1alpha

BACKGROUND

Prostaglandin E2 (PGE2), which exerts its actions via EP receptors (EP1, EP2, EP3, and EP4), is a bioactive metabolite produced by cyclooxygenase (COX)-1 and/or COX-2 from arachidonic acid. In the present study, we investigated whether COX-2-derived PGE2 regulated matrix metalloproteinase (MMP)-3 production in human periodontal ligament (PDL) cells stimulated with interleukin (IL)-1alpha and which EP receptors were involved in PGE2 regulation of IL-1alpha-induced MMP-3 production.

METHODS

Human PDL cells obtained from periodontally healthy subjects were stimulated with vehicle or IL-1alpha in the presence or absence of indomethacin (a COX-1/COX-2 inhibitor), NS-398 (a specific COX- 2 inhibitor), PGE2, EP receptor agonists, dibutyryl cAMP, and forskolin. PGE2 levels were assayed by enzyme-linked immunosorbent assay (ELISA). MMP-3 levels and caseinolytic activities were evaluated by ELISA and casein zymography, respectively.

RESULTS

IL-1alpha enhanced both MMP-3 and PGE2 production. Indomethacin and NS-398 enhanced IL-1alpha-induced MMP-3 production in PDL cells, to the same extent, although both the agents completely inhibited IL-1alpha-induced PGE2 production. Exogenous PGE2 reduced IL-1alpha-induced MMP-3 production in a dose-dependent manner. Butaprost, a selective EP2 agonist, and ONO-AE1-329, a selective EP4 agonist, significantly inhibited IL-1alpha-induced MMP-3 production, although butaprost was less potent than ONO-AE-1-329. Dibutyryl cAMP, a cAMP analog, and forskolin, an adenylate cyclase activator, significantly inhibited IL-1alpha-stimulated MMP-3 production in PDL cells.

CONCLUSIONS

These data suggest that COX-2-dependent PGE2 downregulates IL-1alpha-elicited MMP-3 production by cAMP-dependent pathways via EP2/EP4 receptors in human PDL cells. cAMP-elevating agents such as EP2/EP4 receptor activators may regulate the destruction of extracellular matrix components in periodontal tissue.

Application of periodontal ligament cell sheet for periodontal regeneration: a pilot study in beagle dogs

OBJECTIVE

The ultimate goal of periodontal treatment is to regenerate the damaged periodontal support. Although periodontal ligament (PDL) cells are essential for periodontal regeneration, few studies have reported the transplantation of periodontal ligament cells to periodontal defects. We developed a new method to apply periodontal ligament cells as a sheet to the defect. The aim of this study was to investigate the periodontal healing after application of the periodontal ligament cell sheet in beagle dogs.

METHODS

Autologous periodontal ligament cells were obtained from extracted premolars of each beagle dog. Periodontal ligament cell sheets were fabricated using a temperature-responsive cell culture dish. Dehiscence defects were surgically created on the buccal surface of the mesial roots of bilateral mandibular first molars of each dog. In the experimental group (five defects), periodontal ligament cell sheet with reinforced hyaluronic acid carrier was applied to the defect. Only the hyaluronic acid carrier was applied to the contralateral side as a control (five defects). Eight weeks after surgery, the animals were sacrificed and decalcified specimens were prepared. Healing of the periodontal defects was evaluated histologically and histometrically.

RESULTS

No clinical signs of inflammation or recession of gingiva were observed in both experimental and control groups. In the experimental group, periodontal tissue healing with bone, periodontal ligament and cementum formation was observed in three out of five defects. In the control group, such periodontal tissue formation was not observed except in one defect. Histometric analysis revealed that the formation of new cementum in the experimental group was significantly higher than that in the control group.

CONCLUSION

The periodontal ligament cell sheet has a potential to regenerate periodontal tissue and may become a novel regenerative therapy.

Twist is required for establishment of the mouse coronal suture

Cranial sutures are the growth centres of the skull, enabling expansion of the skull to accommodate rapid growth of the brain. Haploinsufficiency of the human TWIST gene function causes the craniosynostosis syndrome, Saethre-Chotzen syndrome (SCS), in which premature fusion of the coronal suture is a characteristic feature. Previous studies have indicated that Twist is expressed in the coronal suture during development, and therefore that it may play an important role in development and maintenance of the suture. The Twist-null mouse is lethal before the onset of osteogenesis, and the heterozygote exhibits coronal suture synostosis postnatally. In this study we investigated the function of Twist in the development of the mouse coronal suture, by inhibiting Twist synthesis using morpholino antisense oligonucleotides in calvarial organ culture. Decreased Twist production resulted in a narrow sutural space and fusion of bone domains within 48 h after the addition of the morpholino oligonucleotides. Proliferation activity in the sutural cells was decreased, and the expression of osteogenic marker genes such as Runx2 and Fgfr2 was up-regulated in the developing bone domain within 4 h. These results suggest that during establishment of the suture area, Twist is required for the regulation of sutural cell proliferation and osteoblast differentiation.

Intraductal papillary mucinous tumor of the pancreas associated with autosomal dominant polycystic kidney disease

A 43-year-old male with a history of autosomal dominant polycystic kidney disease (ADPKD) was admitted to our center with severe abdominal pain and was diagnosed with acute pancreatitis. CT showed multiple cysts in the liver and both kidneys along with ADPKD and a cystic mass, 4 cm in diameter, in the pancreatic head. The main pancreatic duct was dilated to 1 cm in diameter. The patient was diagnosed with acute pancreatitis due to intraductal papillary mucinous tumor (IPMT), and pancreatoduodenectomy was performed. Histologic examination revealed a multiloculated cystic tumor filled with mucin in the head of the pancreas. Microscopically, the tumor was diagnosed as adenocarcinoma and was found to have invaded the main pancreatic duct. Although, in addition to our case, only seven cases with association between ADPKD and malignant neoplasms have been reported, five of these cases had neoplasms arising from the pancreas. Therefore, we suggest that some genetic interactions may exist between ADPKD and pancreatic carcinogenesis.

Effects of single-visit full-mouth ultrasonic debridement versus quadrant-wise ultrasonic debridement

BACKGROUND

The aim of this randomized controlled clinical trial was to determine the effects of single-visit full-mouth ultrasonic debridement versus quadrant-wise therapy.

MATERIAL AND METHODS

Thirty-six subjects with chronic periodontitis, were randomly allocated to three groups--quadrant-wise ultrasonic debridement, single-visit full-mouth ultrasonic debridement with povidone iodine and single-visit full-mouth ultrasonic debridement with water. Whole-mouth plaque, bleeding on probing (BOP), pocket depth and attachment level were recorded before treatment and 1, 3 and 6 months post-treatment. Plaque and saliva samples were collected for microbiological analysis.

RESULTS

After treatment, all groups showed significant improvement in clinical parameters. Full-mouth treatments resulted in similar improvements in full-mouth mean plaque percentage, probing pocket depth and probing attachment level as conventional therapy. When data were analysed based on pocket depth and tooth type, there was no difference between groups in probing depth reduction or attachment gains. The full-mouth groups demonstrated greater reduction in BOP% and number of pockets > or =5 mm and the total treatment time was significantly shorter. The detection frequencies of periodontal pathogens in plaque and saliva showed slight changes with no difference between groups.

CONCLUSION

Single-visit full-mouth mechanical debridement may have limited additional benefits over quadrant-wise therapy in the treatment of periodontitis, but can be completed in a shorter time.

Oral bacteria in the occluded arteries of patients with Buerger disease

OBJECTIVE

Recent studies have suggested that infectious organisms play a role in vascular diseases. In this study, to explore a possible link between oral infection and Buerger disease, we investigated whether oral (periodontal) bacteria were present in occluded arteries removed from patients with characteristic Buerger disease.

METHODS

Fourteen male patients with a smoking history who had developed characteristics of Buerger disease before the age of 50 years were included in this study. Occluded arteries, including superficial femoral (n = 4), popliteal (n = 2), anterior tibial (n = 4), and posterior tibial (n = 4) arteries, were removed and studied. A periodontist performed a periodontal examination on each patient and collected dental plaque and saliva samples from them at the same time. The polymerase chain reaction method was applied to detect whether seven species of periodontal bacteria--Porphyromonas gingivalis, Tannerella forsythensis, Treponema denticola, Campylobacter rectus, Actinobacillus actinomycetemcomitans, Prevotella intermedia , and Prevotella nigrescens--were present in the occluded arteries and oral samples. In addition, arterial specimens from seven control patients were examined by polymerase chain reaction analysis.

RESULTS

DNA of oral bacteria was detected in 13 of 14 arterial samples and all oral samples of patients with Buerger disease. Treponema denticola was found in 12 arterial and all oral samples. Campylobacter rectus, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythensis, and Prevotella nigrescens were found in 14% to 43% of the arterial samples and 71% to 100% of the oral samples. A pathologic examination revealed that arterial specimens showed the characteristics of an intermediate-chronic-stage or chronic-stage lesion of Buerger disease. All 14 patients with Buerger disease had moderate to severe periodontitis. None of the control arterial samples was positive for periodontal bacteria.

CONCLUSIONS

This is the first study to identify oral microorganisms in the lesions of Buerger disease. Our findings suggest a possible etiologic link between Buerger disease and chronic infections such as oral bacterial infections.

Syndecan-1 Expression During the Formation of Junctional Epithelium

BACKGROUND

Syndecans are cell surface heparan sulfate proteoglycans (PG) which can bind to and modulate the action of growth factors and extracellular matrix components (ECM). Syndecan- 1 has been shown to play important roles during early tooth development and wound healing and repair. Among diverse cells and tissues that comprise the periodontium, the junctional epithelium (JE) constitutes a region of significant anatomic and clinical importance, but the nature of inductive signals and molecules involved in its formation is still unclear. Therefore, this work examines if syndecan-1 is associated with formation of JE, and the distribution of other syndecan family members in the epithelium.

METHODS

In situ hybridization and immunohistochemical techniques were performed using oral tissues from 4-day-old to 10-week-old mice to investigate the expression of syndecan- 1, -2, -3 and -4 mRNAs and their corresponding proteins.

RESULTS

Based on in situ hybridization experiments, all syndecan mRNAs were detected in sulcular epithelium (SE), gingival epithelium (GE), and JE with varying intensity and distribution. Syndecan-1 immunostaining was localized on the cell surface while that of syndecan-2 did not show clear membrane localization. Our experiments in the developing tooth demonstrated that syndecan-1 protein followed characteristic patterns of expression during JE formation and that immunoreactivity for syndecan-1 protein decreased with age when JE cells underwent terminal differentiation.

CONCLUSION

Results of syndecan-1 mRNA and protein expression patterns suggested that this proteoglycan might be an important molecule during the formation of JE.

Down-regulation of interleukin-1alpha-induced matrix metalloproteinase-13 expression via EP1 receptors by prostaglandin E2 in human periodontal ligament cells

In the present study, we investigated the effect of prostaglandin (PG) E2 on matrix metalloproteinase (MMP)-13 production in human periodontal ligament cells stimulated with interleukin (IL)-1alpha. IL-1alpha enhanced both MMP-13 and PGE2 production. Indomethacin, a nonselective cyclooxygenase inhibitor, and NS-398, a specific cyclooxygenase-2 (COX-2) inhibitor, significantly enhanced IL-1alpha-induced MMP-13 production in periodontal ligament cells, although both the agents completely inhibited IL-1alpha-induced PGE2 production. Exogenous PGE2 reduced IL-1alpha-induced MMP-13 mRNA and protein production in a dose-dependent manner. 17-phenyl-omega-trinor PGE2, a selective EP1 receptor agonist, mimicked the inhibitory effect of PGE2 on IL-1alpha-induced MMP-13 mRNA and protein production. On the basis of these data, we suggest that COX-2-dependent PGE2 down-regulates IL-1alpha-elicited MMP-13 production via EP1 receptors in human periodontal ligament cells. PGE2 may be involved in the regulation of destruction of extracellular matrix components in periodontal lesions.

Er:YAG laser irradiation increases prostaglandin E2 production via the induction of cyclooxygenase-2 mRNA in human gingival fibroblasts

BACKGROUND AND OBJECTIVES

It has been reported that both prostaglandin E2 (PGE2) and Er:YAG laser irradiation accelerate wound healing. The stimulatory action of laser seems to occur during the proliferative stage of healing by stimulation of prostaglandin E2 and cyclooxygenase-2 (COX-2), which are crucial early mediators in the natural healing process. We have then investigated the effect of Er:YAG laser irradiation on PGE2 production and COX-2 gene expression in human gingival fibroblast in vitro.

MATERIAL AND METHODS

Cultured fibroblasts were exposed to low-power Er:YAG laser irradiation with an energy density of 3.37 J/cm2. The amount of PGE2 production was measured by enzyme-linked immunosorbent assay (ELISA). COX-2 mRNA level, which is a critical enzyme for PGE2 production, was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Er:YAG laser significantly increased PGE2 production by human gingival fibroblasts. COX-2 mRNA, which was hardly detectable in control, increased dramatically after irradiation. COX-2 inhibitor, NS398, completely inhibited the PGE2 synthesis stimulated by Er:YAG laser irradiation.

CONCLUSION

Our results showed that Er:YAG laser irradiation appears to exert its stimulative action on gingival fibroblasts proliferation through the production of PGE2 via the expression of COX-2. This should be considered as one of the important regulatory pathways to accelerate wound healing after Er:YAG laser irradiation.

Detection and localization of periodontopathic bacteria in abdominal aortic aneurysms

OBJECTIVES

We examined a possible link between periodontal disease and abdominal aortic aneurysm (AAA) by studying resected aneurysmal specimens from AAA patients for the presence of periodontopathic bacteria.

DESIGN

Prospective case control study.

MATERIAL AND METHODS

Thirty-two AAA patients were enrolled in the study. Periodontitis was classified according to the probing depth of periodontal pocket. Thirty-two aneurysmal walls, 16 mural thrombi, 5 atherosclerotic occlusive aorta and 5 control arterial tissue, were examined for 7 periodontal bacteria using polymerase chain reaction (PCR) method. The localization of the bacteria in the aneurysmal/atherosclerotic wall was determined by thromboendarterectomy.

RESULTS

All patients had periodontal disease, and most cases were severe. PCR examination of the aneurysmal specimens showed that 86% were positive for periodontal bacterial DNA. No bacteria were detected in the control specimens. The bacteria were found in both the intimal/medial layer and the adventitial layer of the aneurysmal wall but only in intimal/medial layer of the atherosclerotic occlusive aorta.

CONCLUSION

Periodontopathic bacteria were present in a high percentage of specimens of diseased arteries from AAA patients and were found throughout the whole aneurysmal wall. These bacteria may play a role in the development of AAAs and/or contribute to weakening the aneurysmal wall.

Expression of membrane-bound and soluble receptor activator of NF-kappaB ligand (RANKL) in human T cells

The receptor activator of NF-kappaB ligand (RANKL) and its receptor RANK are critical regulators for immune responses as well as bone remodeling. RANKL is a type II transmembrane protein that has two forms-a membrane-anchored protein and a secreted protein. In this report, we demonstrate for the first time the kinetical expression of two forms of RANKL in human T cells using two monoclonal antibodies (mAbs) against human RANKL, which we newly derived. Freshly isolated T cells rarely expressed mRANKL, while the activation of T cells induced a substantial but minimal level of mRANKL as well as the accumulation of considerable amounts of sRANKL. The addition of the metalloprotease inhibitor KB-R8301 efficiently suppressed the release of sRANKL from activated T cells or RANKL-transfectants, and reciprocally enhanced the mRANKL expression. The membrane form of RANKL was also expressed on the infiltrating T cells in the rheumatoid synovial fluid and in the gingival tissues of patients with periodontitis. Our results demonstrate that the expression of mRANKL on T cells is strictly limited, and the majority of RANKL protein produced by T cells may be active in the soluble form after shedding. The mAbs that were derived in this study may be useful for investigating the regulation and function of RANKL in immune responses and bone remodeling.

A Novel Mutation of the Cathepsin C Gene in a Thai Family With Papillon-Lefèvre Syndrome

BACKGROUND

Papillon-Lefevre syndrome (PLS) is a rare autosomal recessive disorder characterized by palmar- plantar hyperkeratosis and rapid periodontal destruction of both primary and permanent dentitions. It has been shown that the disease is caused by cathepsin C gene (CTSC) mutation leading to the deficiency of cathepsin C enzymatic activity. This study demonstrates the clinical manifestations and CTSC mutational and enzymatic activity analyses in a 5-year-old Thai male PLS patient and his parents.

METHODS

Peripheral blood samples were obtained for genomic DNA isolation. All exons of the CTSC gene were amplified by polymerase chain reaction (PCR) using specific primers. Mutations were identified by DNA sequencing. Verification of the mutation was performed by digestion of PCR products by restriction endonucleases. The cathepsin C enzymatic activity was determined using the synthetic substrate glycyl- L-arginine-7-amino-4-methylcoumarin.

RESULTS

The patient demonstrated classical characteristics of PLS, including hyperkeratotic skin lesions. By the age of 5, all of his primary teeth were extracted due to severe periodontal infection. The parents had no physical abnormalities. The periodontal examination revealed localized mild periodontal destruction. Sequence analysis showed a nucleotide change at position 90 from C >A (c.90C >A) which resulted in a change from cysteine residue to a premature stop codon at the amino acid position 30 in the exon 1. The HpyCH4V digestion revealed that the patient was homozygous, whereas both the father and mother were heterozygous carriers of this mutation. The cathepsin C activity was reduced in the patient's mother, and the activity in the patient was almost completely lost.

CONCLUSIONS

This is the first study to demonstrate a CTSC gene mutation in a Thai family with PLS. The identified mutation is novel and potentially leads to the drastic reduction of the cathepsin C enzymatic activity. This suggests that the mutation is pathogenetic, causing the PLS. Mutational analysis in more members of the family is warranted to identify whether the mutation is inherited from a common ancestor.

Human Periodontal Ligament Cell Sheets Can Regenerate Periodontal Ligament Tissue in an Athymic Rat Model

Conventional periodontal regeneration methods remain insufficient to attain complete and reliable clinical regeneration of periodontal tissues. We have developed a new method of cell transplantation using cell sheet engineering and have applied it to this problem. The purpose of this study was to investigate the characteristics of human periodontal ligament (HPDL) cell sheets retrieved from culture on unique temperature-responsive culture dishes, and to examine whether these cell sheets can regenerate periodontal tissues. The HPDL cell sheets were examined histologically and biochemically, and also were transplanted into a mesial dehiscence model in athymic rats. HPDL cells were harvested from culture dishes as a contiguous cell sheet with abundant extracellular matrix and retained intact integrins that are susceptible to trypsin-EDTA treatment. In the animal study, periodontal ligament-like tissues that include an acellular cementum-like layer and fibrils anchoring into this layer were identified in all the athymic rats transplanted with HPDL cell sheets. This fibril anchoring highly resembles native periodontal ligament fibers; such regeneration was not observed in nontransplanted controls. These results suggest that this technique, based on the concept of cell sheet engineering, can be useful for periodontal tissue regeneration.

Prevotella multiformis sp. nov., isolated from human subgingival plaque

Four bacterial strains isolated from the human oral cavity, PPPA19, PPPA21T, PPPA28 and PPPA30, were characterized by determining phenotypic and biochemical features, cellular fatty acid profiles and the phylogenetic position based on 16S rRNA gene sequence analysis. 16S rRNA gene sequence analysis showed that each of the isolates was a member of the genus Prevotella. These strains were related to Prevotella denticola with about 95 % similarity. The strains were obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-negative rods. However, the cells of these strains were often cocci (coccobacilli), depending on the cultivation time. Colonies of different sizes were detected on Eggerth Gagnon agar plates for these strains. The cells forming large colonies were cocci, whereas those forming small colonies were cocci and rods. However, 16S rRNA gene sequence comparison of colonies of different sizes revealed that only a single organism was present. Although these strains had phenotypic characteristics that were similar to those of P. denticola JCM 8528, they could be differentiated from P. denticola JCM 8528 by aesculin hydrolysis and d-cellobiose fermentation in API 20A tests. DNA–DNA hybridization experiments revealed the genomic distinction of these four strains with respect to P. denticola JCM 8528. On the basis of these data, a novel Prevotella species, Prevotella multiformis sp. nov., is proposed, with PPPA21T (=JCM 12541T=DSM 16608T) as the type strain.

Characterization of the mutant (A115V) tissue-nonspecific alkaline phosphatase gene from adult-type hypophosphatasia

Hypophosphatasia (HOPS) is a clinically heterogeneous heritable disorder characterized by defective skeletal mineralization, deficiency of tissue-nonspecific alkaline phosphatase (TNSALP) activity, and premature loss of deciduous teeth. To date, various mutations in the TNSALP gene have been identified. Especially, A115V located in exon 5 has been detected in a Japanese patient with severe periodontitis and adult-type HOPS. In this study, we have characterized the protein translated from the mutant A115V gene. Wild-type and A115V mutant-type TNSALP cDNA expression vector pcDNA3 have been constructed and transfected to COS-1 cells by lipofectin technique. After 48-h transfection, the cells were subjected to assay ALP activity. In order to identify possible dominant effect of the mutation, we performed co-transfections of wild-type and mutated cDNA, and evaluated the residual activities of each mutation. Detection of TNSALP synthesized by COS-1 cells transfected with the wild- or the mutated-type was also performed by using an immunofluorescent method. ALP activity of cell transfected with the mutant cDNA (A115V) plasmid after 48-h transfection exhibited 0.399+/-0.021 U/mg. As the enzymatic activity of the wild type was taken as 100%, the value of the mutant was estimated as 16.9%. When co-transfected this mutant showed no inhibition of the wild-type enzyme. TNSALP in COS-1 cells with transfected with the mutant exhibited strong fluorescence at the surface of cells as wild-type. This study indicated that the mutant (A115V) TNSALP gene produced the defective ALP enzyme and it could be recessively transmitted and be a disease-causing mutation of the adult-type hypophosphatasia.

Effect of Low-Level Er:YAG Laser Irradiation on Cultured Human Gingival Fibroblasts

BACKGROUND

Low-level laser irradiation has been reported to enhance wound healing. Activation of gingival fibroblasts (GF) has a potential for early wound healing in periodontal treatment. The present study aimed to investigate the direct effect of low-level Er:YAG laser irradiation on gingival fibroblasts proliferation in order to clarify the laser effect on healing.

METHODS

Cultured human gingival fibroblasts (hGF) were exposed to low-power, pulsed Er:YAG laser irradiation with different energy densities ranging from 1.68 to 5.0 J/cm(2). The cultures were analyzed by means of trypan blue staining and counted under a light microscope. The effect of Er:YAG laser on hGF was also evaluated using a transmission electron microscope (TEM).

RESULTS

Cultures irradiated with Er:YAG laser presented faster cell growth when compared with untreated controls. This difference was statistically significant. Transmission electron microscopy revealed rough endoplasmic reticulum, prominent Golgi complexes, and mitochondria after laser irradiation.

CONCLUSIONS

Our results showed that the low-level Er:YAG laser irradiation stimulates the proliferation of cultured gingival fibroblasts. The optimal stimulative energy density was found to be 3.37 J/cm(2). This result suggests that Er:YAG laser irradiation may be of therapeutic benefit for wound healing.