Cervical sympathectomy causes alveolar bone loss in an experimental rat model.

BACKGROUND AND OBJECTIVE: Periodontal disease, a pathological destructive inflammatory condition, is characterized by alveolar bone loss. Recent studies have suggested a correlation between the sympathetic nervous system and bone remodeling. To confirm the importance of the sympathetic nervous system in bone resorption, we investigated the effects of superior cervical ganglionectomy and oral challenge with Porphyromonas gingivalis on alveolar bone loss in rats. MATERIAL AND METHODS: Rats were divided into three groups: group A underwent a sham operation as the control group; group B underwent superior cervical ganglionectomy; and group C underwent a sham operation and oral challenge with P. gingivalis. Horizontal alveolar bone loss was evaluated by measuring the distance between the cemento-enamel junction and the alveolar bone crest. Cytokine gene expression in the gingival tissues was assessed using reverse transcription-polymerase chain reaction analyses. The furcation areas of the mandibular molars were examined histologically. RESULTS: Both superior cervical ganglionectomy and oral challenge with P. gingivalis resulted in accelerated alveolar bone loss. Gingival tissues in the superior cervical ganglionectomy group showed increased expression of the cytokines interleukin-1 alpha, tumor necrosis factor-alpha and interleukin-6. The density of neuropeptide Y-immunoreactive fibers was decreased following superior cervical ganglionectomy. Osteoclasts were observed in the superior cervical ganglionectomy and P. gingivalis-challenged groups. CONCLUSION: Both superior cervical ganglionectomy and oral challenge with P. gingivalis induced alveolar bone loss. These results provide new information on the occurrence of alveolar bone loss, in that both oral challenge with P. gingivalis and superior cervical ganglionectomy are important accelerating factors for alveolar bone loss. Thus, we suggest that the sympathetic nervous system is linked with the prevention of alveolar bone loss.

p63(TP63) elicits strong trans-activation of the MFG-E8/lactadherin/BA46 gene through interactions between the TA and DeltaN isoforms.

We report here that human MFGE8 encoding milk fat globule-EGF factor 8 protein (MFG-E8), also termed 46 kDa breast epithelial antigen and lactadherin, is transcriptionally activated by p63, or TP63, a p53 (TP53) family protein frequently overexpressed in head-and-neck squamous cell carcinomas, mammary carcinomas and so on. Despite that human MFG-E8 was originally identified as a breast cancer marker, and has recently been reported to provide peptides for cancer immunotherapy, its transcriptional control remains an open question. Observations in immunohistochemical analyses, a tetracycline-induced p63 expression system and keratinocyte cultures suggested a physiological link between p63 and MFGE8. By reporter assays with immediately upstream regions of MFGE8, we determined that the trans-activator (TA) isoforms of p63 activate MFGE8 transcription though a p53/p63 motif at -370, which was confirmed by a chromatin immunoprecipitation experiment. Upon siRNA-mediated p63 silencing in a squamous cell carcinoma line, MFG-E8 production decreased to diminish Saos-2 cell adhesion. Interestingly, the DeltaN-p63 isoform lacking the TA domain enhanced the MFGE8-activating function of TA-p63, if DeltaN-p63 was dominant over TA-p63 as typically observed in undifferentiated keratinocytes and squamous cell carcinomas, implying a self-regulatory mechanism of p63 by the TA:DeltaN association. MFG-E8 may provide a novel pathway of epithelial-nonepithelial cell interactions inducible by p63, probably in pathological processes.

In vivo experimental model of human gingival mucosa using immunodeficient mice.

BACKGROUND AND OBJECTIVE: To establish an in vivo experimental model for examining human periodontal tissue, the present study examined several transplant techniques that maintain the structure and characteristics of human gingival mucosa. MATERIAL AND METHODS: Human oral mucosal tissue samples were collected from the gingiva (n = 11), palate (n = 1), and tongue (n = 3). These mucosal grafts were transplanted onto BALB/c nu/scid mice with double-mutant immunodeficiency. Murine skin, twice the size of the graft, was cut open in an ' square superset'-shape. Next, the connective tissue side of the graft was placed onto the murine connective tissue. Immunohistochemical analysis was also performed, using polyclonal rabbit antibody to involucrin, monoclonal antibody to vimentin, monoclonal antibody to CD34, and monoclonal antibody to Ki-67, to determine whether the characteristics of human oral mucosa were maintained. RESULTS: When the connective tissue side of the graft was placed on the murine fascial membrane, the histological structure of the graft was maintained for 60 d. These grafts were examined for human characteristics using human-specific antibodies. Immunohistochemically, the expression patterns of involucrin, vimentin, and Ki-67 indicated that transplanted mucosa revealed normal human characteristics, including differentiation and proliferation up to 80 d. CD34 was not detected in the graft endothelial cells. CONCLUSION: The present study revealed that the novel technique of transplantation of human gingival mucosa in nu/scid mice may serve as an in vivo experimental model of periodontal disease.

Submandibular glands contribute to increases in plasma BDNF levels.

Brain-derived neurotrophic factor (BDNF) promotes survival and differentiation of neural cells in the central and peripheral nervous systems. BDNF has been detected in plasma, but its source has not yet been established. Expression of BDNF mRNA has been identified in the submandibular glands when male rats are exposed to acute immobilization stress. In the present study, we investigated whether plasma BDNF is influenced by the submandibular glands in this model. Acute immobilization stress for 60 min significantly increased the level of plasma BDNF. However, plasma BDNF elevation was markedly suppressed in bilaterally sialoadenectomized rats. There were no significant differences between stressed (60 min) and non-stressed rats with respect to the BDNF mRNA expression in the hippocampus, heart, lung, liver, pancreas, or spleen, as determined by real-time polymerase chain-reaction. These findings suggest that the submandibular glands may be the primary source of plasma BDNF in conditions of acute immobilization stress.

Restraint stress enhances alveolar bone loss in an experimental rat model.

BACKGROUND AND OBJECTIVE: The purpose of the present study was to examine the effects of restraint stress on periodontal breakdown resulting from Porphyromonas gingivalis-challenged periodontitis in rats. MATERIAL AND METHODS: To examine the influence of restraint stress on periodontal breakdown, rats were orally challenged with the periodontal pathogen P. gingivalis. Twenty male, specific pathogen-free (SPF) 3-wk-old, Sprague-Dawley rats were divided into four groups: group A (controls), group B (exposed to restraint stress for 12 h/d for 22 d), group C (orally challenged with P. gingivalis), and group D (exposed to restraint stress for 12 h/d for 22 d and orally challenged with P. gingivalis). After 22 d, all animals were killed. The distance from the alveolar bone crest to the cemento-enamel junction was determined, concentrations of adrenocorticotropic hormone were measured as stress markers, and atrophy of the thymus and spleen were assessed. In addition, the furcation area of the maxillary molars was examined histologically, while gingival cytokine gene expression was assessed by mRNA using reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: In the restrained group, all stress markers were elevated, and the thymus and spleen were atrophied. Combined restraint stress and oral challenge with P. gingivalis resulted in significantly higher bone loss, and osteoclasts were observed. RT-PCR analysis revealed low cytokine gene expression in the restrained groups. CONCLUSION: These results suggest that the presence of restraint stress significantly enhances the progression of P. gingivalis-challenged periodontitis in rats.

Immobilization stress induces BDNF in rat submandibular glands.

Brain-derived neurotrophic factor (BDNF) promotes survival and differentiation of the cells of the central and peripheral nervous systems. BDNF has been identified in non-neural tissue, including the heart, lung, platelets, lymphocytes, and lacrimal glands. Immobilization stress modifies BDNF mRNA expression in some organs. The present study examines the effect of immobilization stress on BDNF, and its receptor TrkB, in male rat submandibular glands. Increased BDNF mRNA and protein expression were observed in duct cells as a result of immobilization stress, as demonstrated by real-time PCR, Western blot, immunohistochemistry, and analysis by microdissection. TrkB mRNA was not detected in salivary gland tissue, or oral or esophageal mucosa, by RT-PCR. Rat submandibular gland was thus identified as an organ which expresses BDNF. Furthermore, the results of this study suggest that increased salivary BDNF expression occurs following immobilization stress.

Growth of human squamous cell carcinoma xenografts in mice is inhibited by local angiostatin gene therapy.

The possibility of inhibiting tumor growth by blocking the formation of new tumor vessels has recently received attention. Antiangiogenic tumor therapies have recently attracted intense interest because of their direct endothelial targeting and the absence of drug resistance. Local antiangiogenic gene therapy for cancer offers a potential way to achieve sustained therapeutic release of antiangiogenic substances. As a step toward this goal, we used liposomes complexed to angiostatin cDNA and targeted to human squamous cell carcinoma cell lines in vivo. Tumor cells expressing angiostatin after local gene transfer showed markedly reduced vascularity and contained many apoptotic tumor cells. These results demonstrate the potential utility of liposome-derived angiostatin for adjuvant therapy of oral cancer in humans.

Immunohistochemical heterogeneity of type 1 blood group antigen expressions in testicular germ cell tumors.

The immunohistochemical expression of type 1 blood group antigens (type 1 BGAs) was analyzed for 30 cases of testicular germ cell tumors (TGCTs), using monoclonal antibodies against DU-PAN-2, CA19-9, Lewis(a) (Le(a)), and Lewis(b) (Le(b)). DU-PAN-2 was expressed very frequently in all of the embryonal carcinomas (ECs). CA19-9 expression was demonstrated in 53% of ECs, but the number of positive cells was generally smaller than that for DU-PAN-2. CA19-9-negative ECs tended to show a higher number of DU-PAN-2-positive cells compared to CA19-9-positive ECs, and ECs in which DU-PAN-2 was more strongly expressed showed a relatively frequent expression of CA19-9. In 36% of seminomas and 56% of yolk sac tumors (YSTs), DU-PAN-2 was weakly expressed, and the positive cells were few in number. Little or no expression of CA19-9 was demonstrated in seminomas and YSTs. Regarding Le(a) and Le(b), the expressions were found to be limited to teratomas at a frequency of 57% and 86%, respectively, with the exception of one EC positive for Lea and one YST positive for Leb. Eighty-six percent of teratomas showed expressions of DU-PAN-2 and CA19-9. DU-PAN-2 was also seen in some intratubular malignant germ cells. The antibodies used were all negative for choriocarcinomas, syncytiotrophoblastic giant cells, and normal testicular tissues. The antigen expressions were predominantly observed on the surface of tumor cells developing luminal structures. In conclusion, although CA19-9 was relatively specific for ECs, it should be emphasized that ECs were rather characteristic of extensive DU-PAN-2 expression. Particularly in CA19-9-negative ECs, a combined analysis of DU-PAN-2 and CA19-9 would be helpful in confirming the histopathologic diagnosis of TGCTs. The clinical significance of DU-PAN-2 in ECs as a tumor marker remains to be clarified. Le(a) and Le(b) expressions were thought to be related to the differentiation or maturation rather than to the malignant transformation in TGCTs.

Acinic cell carcinoma of the sublingual gland accompanied by bone formation.

A rare case of acinic cell carcinoma of the sublingual gland accompanied by bone formation is reported. The patient is a 79-year-old male who was referred to Yokohama Minami Kyosai Hospital with sublingual swelling. A tumor mass, 20 x 10 mm in diameter, was detected on the right side of the floor of the mouth. Computed tomography (CT) revealed a mass lesion with calcification in the sublingual gland. The patient underwent total sialadenectomy of the sublingual gland with conservation of the lingual nerve. Histologically, the lesion showed amylase-positive atypical cells with thyroid gland-like arrangement, and mature bone tissue in the stroma. Based on these findings, the tumor was diagnosed as acinic cell carcinoma accompanied by bone formation. Postoperative recovery was uneventful, and two years after surgery, there are no signs of distant metastases or recurrence.

Telomerase activity in oral cancer.

Telomerase activity can be detected in most human cancers. This is consistent with the telomere hypothesis, which predicts upregulation of telomerase expression after a number of mitotic divisions to prevent the progressive and catastrophic loss of telomeres. However, telomerase has not been fully analyzed in oral cancers. In this report, telomerase activity was analyzed in 31 human oral malignant tumors, 11 leukoplakias, three pleomorphic adenomas, and 40 samples taken from normal tissues of the oral cavity, using a polymerase chain reaction (PCR)-based telomeric repeat amplification protocol assay. Telomerase activity was detected in most oral cancers [squamous cell carcinoma (SCC), non-Hodgkin's lymphoma, adenoid cystic carcinomas, mucoepidermoid carcinoma, osteosarcoma, acinic cell carcinoma, rhabdomyosarcoma]. None of the normal tissues or pleomorphic adenomas displayed telomerase activity. In leukoplakia, telomerase activity was seen in moderate or severe dysplastic tissue and carcinoma in situ. Mild dysplasia did not reveal telomerase activity. In SCC, there was no clear association between relative telomerase activity and grade or stage. These results suggest that detection of telomerase activity in oral tissues could be used to differentiate malignant from benign or normal tissues.

Histopathological assessment of localized proliferation in cases of Bowen's disease using immunostaining and a laser cytometer.

In order to evaluate the localized proliferative activity of intratumor cells in Bowen's disease using tissue sections, skin specimens from ten patients were compared with skin samples from seven normal individuals for their expression of proliferating cell nuclear antigen (PCNA), Ki-67 immunostaining and intranuclear DNA contents, quantitated with a laser cytometer (LCM). In normal epidermis, the largest proportion of PCNA- and Ki-67-positive cells was observed in the basal cell layer, with the amounts decreasing through the suprabasal cell layer towards the prickle cell layer. Examination by LCM also revealed the highest average fluorescence intensity of individual nuclei in the basal cell layer and, as with the immunohistological parameters, reducing towards the upper layer of the epidermis. In the Bowen's disease tissue sections, the largest proportion of PCNA- and Ki-67-positive cells was found in contact with the basement membrane (base of the tumor), with lower amounts in the center of the tumor nest and in the marginal epidermis. The average fluorescence intensities of individual nuclei were in line with these results. These results show that tumor cells distributed in Bowen's disease tumor nests have different proliferative activities depending on their location.

A case of central carcinoma of the mandible arising from a recurrent odontogenic keratocyst: delineation of surgical margins and reconstruction with bilateral rectus abdominis myocutaneous free flaps.

A case of central carcinoma of the mandible arising from a recurrent odontogenic keratocyst is reported. A 38-year-old man was admitted to the Tokai University Hospital due to postoperative infection of a recurrent odontogenic keratocyst of the left mandible. He had had a cystectomy for an odontogenic keratocyst 4 years ago. The lesion revealed bony destruction of the mandible with worm-eating shaped margins with extension to the facial skin. A biopsy specimen revealed squamous cell carcinoma. The mandible was resected with facial skin and the sublingual space was dissected to preserve the lingual nerve. The oral and the facial resections were reconstructed with a titanium plate and bilateral rectus abdominis myocutaneous free flaps. The plate was removed due to infection around the margins and readjustment of the flaps was conducted 5 months after the surgery. He has not had a local relapse, metastasis, or incisional hernia for 8 months following surgery. Good occlusion has been attained by the residual mandible, and he is able to eat without any problems.