Toshiya Morozumi

Bio: Toshiya Morozumi is an academic researcher from Kanagawa Dental College. The author has contributed to research in topics: Periodontitis & Chronic periodontitis. The author has an hindex of 16, co-authored 44 publications receiving 704 citations. Previous affiliations of Toshiya Morozumi include University at Buffalo & Niigata University.

Smoking cessation increases gingival blood flow and gingival crevicular fluid

Abstract: Objectives: The purpose of the present study was to determine the effect of smoking cessation on gingival blood flow (GBF) and gingival crevicular fluid (GCF). Material and Methods: Sixteen male smokers (aged 22–39 (25.3±4.0) years), with no clinical signs of periodontal and systemic diseases, were recruited. The experiment was performed before (baseline) and at 1, 3 and 5 days, and at 1, 2, 4 and 8 weeks after smoking cessation. The status of smoking and smoking cessation was verified by exhaled carbon monoxide (CO) concentration, and by serum nicotine and cotinine concentrations. A laser Doppler flowmeter was used to record relative blood flow continuously, on three gingival sites of the left maxillary central incisor (mid-labial aspect of the gingival margin and bilateral interdental papillae). The GCF was collected at the mesio- and disto-labial aspects of the left maxillary central incisor and the volume was calculated by the Periotron 6000® system. The same measurements except for the GBF were performed on 11 non-smoking controls (four females and seven males), aged 23–27 (24.4±1.2) years. Results: Eleven of 16 smokers successfully completed smoking cessation for 8 weeks. At 1 day after smoking cessation, there was a significantly lower CO concentration than at baseline (p<0.01). Also, nicotine and cotinine concentrations markedly decreased at the second measurement. The GBF rate of smokers was significantly higher at 3 days after smoking cessation compared to the baseline (p<0.01). While the GCF volume was significantly increased at 5 days after smoking cessation compared to the baseline (p<0.01), it was significantly lower than that of non-smokers until 2 weeks after smoking cessation (p<0.01). Conclusion: The results show that the gingival microcirculation recovers to normal in the early stages of smoking cessation, which could activate the gingival tissues metabolism/remodeling, and contribute to periodontal health.

Altered gene expression levels of matrix metalloproteinases and their inhibitors in periodontitis-affected gingival tissue.

Abstract: Background: The balance between the degradation and synthesis of extracellular matrix determines periodontal attachment levels and alveolar bone matrix concentration in periodontal diseases. Matrix metalloproteinases (MMPs) are known to degrade periodontal ligamental attachment and bone matrix proteins. The purpose of this study was to examine the effect of different expression levels of MMPs and their inhibitors, the tissue inhibitors of matrix metalloproteinases (TIMPs), in periodontitis. Methods: Sixteen inflamed gingival tissue samples from subjects with generalized chronic periodontitis and 14 control tissue samples from systemically and periodontally healthy subjects were evaluated. The total RNA was extracted, and the transcript levels for MMP-1, -3, -9, and -13 and TIMP-1, -2, -3, and -4 relative to b-actin were determined by quantitative real-time reverse transcription-polymerase chain reaction. Results: Gene transcript levels for MMP-1 and TIMP-4 were significantly higher in periodontitis-affected gingival tissues (P <0.05). MMP-3, -9, and -13 and TIMP-1 mRNAs also were elevated in periodontitis; however, the difference was not statistically significant. TIMP-2 and -3 mRNA levels were similar in healthy and diseased gingivae. The ratios of MMP-1/TIMP-2 (P <0.01), MMP-3/TIMP-2 (P <0.05), MMP-9/TIMP-2 (P <0.05), and MMP-1/TIMP-3 (P <0.01) from periodontitis lesions were significantly higher than those in the control tissues. Conclusions: Upregulated MMP expression and an increased MMP/TIMP ratio indicate that a potential imbalance between degradation and synthesis of extracellular matrix persists in periodontitis-affected gingival tissues. This process may be responsible for increased tissue breakdown in periodontitis. J Periodontol 2008;79:166-173.

Matrix metalloproteinase-1 and -3 gene promoter polymorphisms in Japanese patients with periodontitis.

Abstract: Background/aims: Matrix metalloproteinase (MMP)-1 and MMP-3 have important roles in the connective tissue remodelling and destruction processes in periodontitis. MMP-1 1G/2G (−1607) and MMP-3 5A/6A (−1171) polymorphisms have been identified and appear to influence the transcription of the genes. The aim of this study was to investigate whether these gene promoter polymorphisms were associated with the susceptibility to periodontitis. Material and Methods: Genomic DNA was obtained from 37 generalised aggressive, 205 slight-to-severe generalised chronic-periodontitis patients and 142 healthy subjects. All subjects were non-smoking Japanese. We genotyped by using TaqMan® PCR assay. The statistics were analysed by χ2-test. Results: We found no significant differences in genotype distributions, allele frequencies, carriage rates and haplotype frequencies in the MMP-1 and the MMP-3 gene promoter polymorphisms among all groups. The distributions of MMP-1 and MMP-3 genotypes in our study were different from those of previously reported in Caucasians or Brazilians, but consistent with previously reported in Japanese. Conclusion: Our data did not support the hypothesis that MMP-1 and/or MMP-3 gene promoter polymorphisms influenced the susceptibility to periodontitis in Japanese patients, indicating MMP-1 and MMP-3 expressions were regulated by complex processes such as cytokine network in periodontal disease rather than gene polymorphisms.

Effects of Irrigation With an Antiseptic and Oral Administration of Azithromycin on Bacteremia Caused by Scaling and Root Planing

Abstract: Background: Transient bacteremia frequently occur secondary to several periodontal procedures. The purpose of the present study is to investigate the effects of irrigation with an essential oil–containing antiseptic (EO) and oral administration of azithromycin (AZM) on bacteremia caused by scaling and root planing (SRP). Methods: Thirty patients with chronic periodontitis were randomly assigned to three groups (control, EO, and AZM). The EO group received quadrant subgingival irrigation with EO, and mouthrinsing was continued at home for 1 week. Oral administration of AZM was started 3 days before SRP in the AZM group. No adjunctive treatment was performed before SRP in the control group. Peripheral blood and subgingival plaque were collected at baseline and after 1 week. The second blood sample was taken 6 minutes after the initiation of quadrant SRP. The blood samples were cultured and analyzed for bacteremia. Quantitative analysis of periodontopathic bacteria in the sulcus was performed using the polymerase chain reaction Invader method. Results: Bacteremia incidence rates were 90%, 70%, and 20% for the control, EO, and AZM groups, respectively. Significant reduction of the incidence of bacteremia was shown in the AZM group only (P <0.01). Subgingival bacterial counts significantly decreased in both the EO and AZM groups (P <0.01). Conclusions: Quadrant SRP frequently induced bacteremia. Although AZM was effective in reducing bacteremia incidence, EO showed less effectiveness. J Periodontol 2010;81:1555-1563.

Altered gene expression in leukocyte transendothelial migration and cell communication pathways in periodontitis-affected gingival tissues.

Abstract: Abe D, Kubota T, Morozumi T, Shimizu T, Nakasone N, Itagaki M, Yoshie H. Altered gene expression in leukocyte transendothelial migration and cell communication pathways in periodontitis-affected gingival tissues. J Periodont Res 2011; 46: 345–353. © 2011 John Wiley & Sons A/S Background and Objective: Gene expression is related to the pathogenesis of periodontitis and plays a crucial role in local tissue destruction and disease susceptibility. The aims of the present study were to identify the expression of specific genes and biological pathways in periodontitis-affected gingival tissue using microarray and quantitative real-time RT-PCR analyses. Material and Methods: Healthy and periodontitis-affected gingival tissues were taken from three patients with severe chronic periodontitis. Total RNAs from six gingival tissue samples were used for microarray analyses. Data-mining analyses, such as comparisons, gene ontology and pathway analyses, were performed and biological pathways with a significant role in periodontitis were identified. In addition, quantitative real-time RT-PCR analysis was performed on samples obtained from 14 patients with chronic periodontitis and from 14 healthy individuals in order to confirm the results of the pathway analysis. Results: Comparison analyses found 15 up-regulated and 13 down-regulated genes (all of which showed a change of more than twofold in expression levels) in periodontitis-affected gingival tissues. Pathway analysis identified 15 up-regulated biological pathways, including leukocyte transendothelial migration, and five down-regulated pathways, including cell communication. Quantitative real-time RT-PCR verified that five genes in the leukocyte transendothelial migration pathway were significantly up-regulated, and four genes in the cell communication pathway were significantly down-regulated, which was consistent with pathway analysis. Conclusion: We identified up-regulated genes (ITGB-2, MMP-2, CXCL-12, CXCR-4 and Rac-2) and down-regulated genes (connexin, DSG-1, DSC-1 and nestin) in periodontitis-affected gingival tissues; these genes may be related to the stimulation of leukocyte transendothelial migration and to the the impairment of cell-to-cell communication in periodontitis.

Risk factors for periodontal disease.

Abstract: Risk factors play an important role in an individual's response to periodontal infection. Identification of these risk factors helps to target patients for prevention and treatment, with modification of risk factors critical to the control of periodontal disease. Shifts in our understanding of periodontal disease prevalence, and advances in scientific methodology and statistical analysis in the last few decades, have allowed identification of several major systemic risk factors for periodontal disease. The first change in our thinking was the understanding that periodontal disease is not universal, but that severe forms are found only in a portion of the adult population who show abnormal susceptibility. Analysis of risk factors and the ability to statistically adjust and stratify populations to eliminate the effects of confounding factors have allowed identification of independent risk factors. These independent but modifiable, risk factors for periodontal disease include lifestyle factors, such as smoking and alcohol consumption. They also include diseases and unhealthy conditions such as diabetes mellitus, obesity, metabolic syndrome, osteoporosis, and low dietary calcium and vitamin D. These risk factors are modifiable and their management is a major component of the contemporary care of many periodontal patients. Genetic factors also play a role in periodontal disease and allow one to target individuals for prevention and early detection. The role of genetic factors in aggressive periodontitis is clear. However, although genetic factors (i.e., specific genes) are strongly suspected to have an association with chronic adult periodontitis, there is as yet no clear evidence for this in the general population. It is important to pursue efforts to identify genetic factors associated with chronic periodontitis because such factors have potential in identifying patients who have a high susceptibility for development of this disease. Many of the systemic risk factors for periodontal disease, such as smoking, diabetes and obesity, and osteoporosis in postmenopausal women, are relatively common and can be expected to affect most patients with periodontal disease seen in clinics and dental practices. Hence, risk factor identification and management has become a key component of care for periodontal patients.

Matrix metalloproteinases: contribution to pathogenesis, diagnosis and treatment of periodontal inflammation.

Abstract: Matrix metalloproteinases (MMPs) form a family of enzymes that mediate multiple functions both in the tissue destruction and immune responses related to periodontal inflammation. The expression and activity of MMPs in non-inflamed periodontium is low but is drastically enhanced to pathologically elevated levels due to the dental plaque and infection-induced periodontal inflammation. Soft and hard tissue destruction during periodontitis and peri-implantitis are thought to reflect a cascade of events involving bacterial virulence factors/enzymes, pro-inflammatory cytokines, reactive oxygen species and MMPs. However, recent studies suggest that MMPs can also exert anti-inflammatory effects in defence of the host by processing anti-inflammatory cytokines and chemokines, as well as by regulating apoptotic and immune responses. MMP-inhibitor (MMPI)-drugs, such as doxycycline, can be used as adjunctive medication to augment both the scaling and root planing-treatment of periodontitis locally and to reduce inflammation systematically. Furthermore, MMPs present in oral fluids (gingival crevicular fluid (GCF), peri-implant sulcular fluid (PISF), mouth-rinses and saliva) can be utilized to develop new non-invasive, chair/bed-side, point-of-care diagnostics for periodontitis and dental peri-implantitis.

Mapping the Pathogenesis of Periodontitis: A New Look

Abstract: Chronic adult periodontitis is a bacterially induced chronic inflammatory disease that destroys the connective tissue and bone that support teeth. Concepts of the specific mechanisms involved in the disease have evolved with new technologies and knowledge. Histopathologic observations of diseased human tissues were used previously to speculate on the causes of periodontitis and to describe models of pathogenesis. Experimental evidence later emerged to implicate bacterial plaque deposits as the primary factor initiating periodontitis. At the same time, specific bacteria and immunoinflammatory mechanisms were differentially implicated in the disease. In the mid-1990s, early insights about complex diseases, such as periodontitis, led to new conceptual models of the pathogenesis of periodontitis. Those models included the bacterial activation of immunoinflammatory mechanisms, some of which targeted control of the bacterial challenge and others that had adverse effects on bone and connective tissue remodeling. Such models also acknowledged that different environmental and genetic factors modified the clinical phenotype of periodontal disease. However, the models did not capture the dynamic nature of the biochemical processes, i.e., that innate differences among individuals and changes in environmental factors may accelerate biochemical changes or dampen that shift. With emerging genomic, proteomic, and metabolomic data and systems biology tools for interpreting data, it is now possible to begin describing the basic elements of a new model of pathogenesis. Such a model incorporates gene, protein, and metabolite data into dynamic biologic networks that include disease-initiating and -resolving mechanisms. This type of model has a multilevel framework in which the biochemical networks that are regulated by innate and environmental factors can be described and the interrelatedness of networks can be captured. New models in the next few years will be merely frameworks for integrating key knowledge as it becomes available from the "-omics" technologies. However, it is possible to describe some of the key elements of the new models and discuss distinctions between the new and older models. It is hoped that improved conceptual models of pathogenesis will assist in focusing new research and speed the translation of new data into practical applications.

Mechanisms of action of environmental factors – tobacco smoking

Abstract: Aim: To review the potential biological mechanisms underlying the effects of tobacco smoking on periodontitis. Main findings: Smoking has major effects on the host response, but there are also a number of studies that show some microbiological differences between smokers and non-smokers. Smoking has a long-term chronic effect on many important aspects of the inflammatory and immune responses. Histological studies have shown alterations in the vasculature of the periodontal tissues in smokers. Smoking induces a significant systemic neutrophilia, but neutrophil transmigration across the periodontal microvasculature is impeded. The suppression of neutrophil cell spreading, chemokinesis, chemotaxis and phagocytosis have been described. Protease release from neutrophils may be an important mechanism in tissue destruction. Tobacco smoke has been found to affect both cell-mediated immunity and humoral immunity. Research on gingival crevicular fluid has demonstrated that there are lower levels of cytokines, enzymes and possibly polymorphonuclear cells in smokers. In vitro studies have shown detrimental effects of nicotine and some other tobacco compounds on fibroblast function, including fibroblast proliferation, adhesion to root surfaces and cytotoxicity. Conclusion: Tobacco smoking has widespread systemic effects, many of which may provide mechanisms for the increased susceptibility to periodontitis and the poorer response to treatment.