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Taslima F, Abdelhamid M, Zhou C, Chen Y, Jung CG, Michikawa M. Tooth Loss Induces Memory Impairment and Glial Activation in Young Wild-Type Mice. J Alzheimers Dis Rep 2022; 6:663-675. [PMID: 36506484 PMCID: PMC9696677 DOI: 10.3233/adr-220053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/08/2022] [Indexed: 11/06/2022] Open
Abstract
Background Tooth loss is closely associated with Alzheimer's disease (AD). Previously, we reported that tooth loss induced memory impairment in amyloid precursor protein knock-in mice by decreasing neuronal activity and synaptic protein levels and increasing glial activation, neuroinflammation, and pyramidal neuronal cell loss without altering amyloid-β levels in the hippocampus. However, the effects of tooth loss in young wild-type mice have not been explored yet. Objective We investigated the effects of tooth loss on memory impairment, neuronal activity, synaptic protein levels, glial activation, and pyramidal neuronal cell loss in young wild-type mice. Methods Two-month-old wild-type mice were randomly divided into control and tooth loss groups. In the tooth loss group, maxillary molar teeth on both sides were extracted, whereas no teeth were extracted in the control group. Two months after tooth extraction, we performed a novel object recognition test to evaluate memory function. Glial activation, neuronal activity, synaptic protein levels, and the number of pyramidal neurons were evaluated using immunofluorescence staining, immunohistochemistry, and western blotting. Results The tooth loss group exhibited memory impairment and decreased neuronal activity and the levels of synaptic proteins in both the hippocampus and cortex. Moreover, tooth loss increased the activation of phosphorylated c-Jun N-terminal kinase (JNK), heat shock protein 90 (HSP90), and glial activation and reduced the number of pyramidal neurons in the hippocampus. Conclusion Tooth loss in the young wild-type mice will attenuate neuronal activity, decrease synaptic protein levels, and induce pyramidal neuronal loss, and eventually lead to memory impairment.
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Affiliation(s)
- Ferdous Taslima
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Mona Abdelhamid
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Chunyu Zhou
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Yuxin Chen
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Cha-Gyun Jung
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan,Correspondence to: Cha-Gyun Jung, PhD and Makoto Michikawa, MD, PhD, Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 Aichi, Japan. Tel.: +81 52 853 8141; Fax: +81 52 841 3480; E-mail: . (Cha-Gyun Jung) and Tel.: +81 52 853 8139; Fax: +81 52 841 3480; E-mail: . (Makoto Michikawa)
| | - Makoto Michikawa
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan,Correspondence to: Cha-Gyun Jung, PhD and Makoto Michikawa, MD, PhD, Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 Aichi, Japan. Tel.: +81 52 853 8141; Fax: +81 52 841 3480; E-mail: . (Cha-Gyun Jung) and Tel.: +81 52 853 8139; Fax: +81 52 841 3480; E-mail: . (Makoto Michikawa)
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Furukawa M, Tada H, Wang J, Yamada M, Kurosawa M, Satoh A, Ogiso N, Shikama Y, Matsushita K. Molar loss induces hypothalamic and hippocampal astrogliosis in aged mice. Sci Rep 2022; 12:6409. [PMID: 35437315 PMCID: PMC9016068 DOI: 10.1038/s41598-022-10321-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 04/05/2022] [Indexed: 11/09/2022] Open
Abstract
Age-related tooth loss impedes mastication. Epidemiological and physiological studies have reported that poor oral hygiene and occlusion are associated with cognitive decline. In the present study, we analyzed the mechanism by which decreased occlusal support following bilateral extraction of the maxillary first molars affects cognitive functions in young and aged mice and examined the expression of brain-function-related genes in the hippocampus and hypothalamus. We observed decreased working memory, enhanced restlessness, and increased nocturnal activity in aged mice with molar extraction compared with that in mice with intact molars. Furthermore, in the hypothalamus and hippocampus of molar-extracted aged mice, the transcript-level expression of Bdnf, Rbfox3, and Fos decreased, while that of Cdkn2a and Aif1 increased. Thus, decreased occlusal support after maxillary first molar extraction may affect cognitive function and activity in mice by influencing aging, neural activity, and neuroinflammation in the hippocampus and hypothalamus.
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Affiliation(s)
- Masae Furukawa
- Department of Oral Disease Research, Geroscience Research Center, National Center for Geriatrics and Gerontology, Obu, Japan.
| | - Hirobumi Tada
- Department of Nutrition, Faculty of Wellness, Shigakkan University, Obu, Japan.,Department of Inflammation and Immunosenescence, Geroscience Research Center, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Jingshu Wang
- Department of Oral Disease Research, Geroscience Research Center, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Mitsuyoshi Yamada
- Department of Oral Disease Research, Geroscience Research Center, National Center for Geriatrics and Gerontology, Obu, Japan.,Department of Operative Dentistry, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Mie Kurosawa
- Department of Oral Disease Research, Geroscience Research Center, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Akiko Satoh
- Department of Integrative Physiology, Geroscience Research Center, National Center for Geriatrics and Gerontology, Obu, Japan.,Department of Integrative Physiology, Institute of Development, Aging, and Cancer, Tohoku University, Sendai, Japan
| | - Noboru Ogiso
- Department of Laboratory of Experimental Animals, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Yosuke Shikama
- Department of Oral Disease Research, Geroscience Research Center, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Kenji Matsushita
- Department of Oral Disease Research, Geroscience Research Center, National Center for Geriatrics and Gerontology, Obu, Japan.
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Murakami A, Hara T, Yamada-Kubota C, Kuwahara M, Ichikawa T, Minagi S. Lack of occlusal support did not impact amyloid β deposition in APP knock-in mice. J Prosthodont Res 2021; 66:161-166. [PMID: 34305086 DOI: 10.2186/jpr.jpr_d_20_00205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
PURPOSE The lack of occlusal support is an epidemiological risk factor linked to Alzheimer's disease. This study sought to assess the relationship between amyloid β (Aβ) deposition and the lack of occlusal support in amyloid precursor protein (APP) knock-in mice. METHODS Sixteen experimental animals were divided into two groups. The upper molars were extracted in the extraction group (group E), and a sham operation was performed in the control group (group C). The Morris water maze test was performed 4 months after the tooth extraction. Aβ immunohistochemical staining and Nissl staining of the hippocampus were performed. Hippocampal plasma corticosterone and Aβ protein levels were measured. RESULTS In the maze task, the escape latency was significantly longer in group E than in group C. In the probe trials, the time elapsed in the target quadrant was significantly shorter in group E than in group C. The number of hippocampal neurons decreased in group E. There was no significant difference in the plasma corticosterone levels between the two groups, indicating that there was no effect of chronic stress on the behavioral results. Hippocampal Aβ40 and Aβ42 protein levels and Aβ deposition areas by immunohistochemical staining were not significantly different between the two groups. CONCLUSIONS Aβ deposition was not increased in the hippocampus of molarless APP knock-in mice. As such, it appears that cognitive impairment due to a lack of occlusal support was not related to Aβ deposition.
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Affiliation(s)
- Asuka Murakami
- Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University
| | - Tetsuya Hara
- Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University
| | - Chie Yamada-Kubota
- Department of Occlusion and Removable Prosthodontics, Okayama University Hospital
| | - Miho Kuwahara
- Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University
| | - Tomoka Ichikawa
- Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University
| | - Shogo Minagi
- Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University
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Patel S, Howard D, Chowdhury N, Derieux C, Wellslager B, Yilmaz Ö, French L. Characterization of Human Genes Modulated by Porphyromonas gingivalis Highlights the Ribosome, Hypothalamus, and Cholinergic Neurons. Front Immunol 2021; 12:646259. [PMID: 34194426 PMCID: PMC8236716 DOI: 10.3389/fimmu.2021.646259] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 05/20/2021] [Indexed: 12/12/2022] Open
Abstract
Porphyromonas gingivalis, a bacterium associated with periodontal disease, is a suspected cause of Alzheimer's disease. This bacterium is reliant on gingipain proteases, which cleave host proteins after arginine and lysine residues. To characterize gingipain susceptibility, we performed enrichment analyses of arginine and lysine proportion proteome-wide. Genes differentially expressed in brain samples with detected P. gingivalis reads were also examined. Genes from these analyses were tested for functional enrichment and specific neuroanatomical expression patterns. Proteins in the SRP-dependent cotranslational protein targeting to membrane pathway were enriched for these residues and previously associated with periodontal and Alzheimer's disease. These ribosomal genes are up-regulated in prefrontal cortex samples with detected P. gingivalis sequences. Other differentially expressed genes have been previously associated with dementia (ITM2B, MAPT, ZNF267, and DHX37). For an anatomical perspective, we characterized the expression of the P. gingivalis associated genes in the mouse and human brain. This analysis highlighted the hypothalamus, cholinergic neurons, and the basal forebrain. Our results suggest markers of neural P. gingivalis infection and link the cholinergic and gingipain hypotheses of Alzheimer's disease.
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Affiliation(s)
- Sejal Patel
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Derek Howard
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Nityananda Chowdhury
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Casey Derieux
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Bridgette Wellslager
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Özlem Yilmaz
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC, United States
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
| | - Leon French
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Institute for Medical Science, University of Toronto, Toronto, ON, Canada
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5
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Taslima F, Jung CG, Zhou C, Abdelhamid M, Abdullah M, Goto T, Saito T, Saido TC, Michikawa M. Tooth Loss Induces Memory Impairment and Gliosis in App Knock-In Mouse Models of Alzheimer's Disease. J Alzheimers Dis 2021; 80:1687-1704. [PMID: 33720883 DOI: 10.3233/jad-201055] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Epidemiological studies have shown that tooth loss is associated with Alzheimer's disease (AD) and dementia. However, the molecular and cellular mechanisms by which tooth loss causes AD remain unclear. OBJECTIVE We investigated the effects of tooth loss on memory impairment and AD pathogenesis in AppNL-G-F mice. METHODS Maxillary molar teeth on both sides were extracted from 2-month-old AppNL-G-F mice, and the mice were reared for 2 months. The short- and long-term memory functions were evaluated using a novel object recognition test and a passive avoidance test. Amyloid plaques, amyloid-β (Aβ) levels, glial activity, and neuronal activity were evaluated by immunohistochemistry, Aβ ELISA, immunofluorescence staining, and western blotting. The mRNA expression levels of neuroinflammatory cytokines were determined by qRT-PCR analysis. RESULTS Tooth loss induced memory impairment via an amyloid-cascade-independent pathway, and decreased the neuronal activity, presynaptic and postsynaptic protein levels in both the cortex and hippocampus. Interestingly, we found that tooth loss induced glial activation, which in turn leads to the upregulation of the mRNA expression levels of the neuroinflammation cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β in the hippocampus. We also found that tooth loss activated a stress-activated protein kinase, c-Jun N-terminal kinase (JNK), and increased heat shock protein 90 (HSP90) levels in the hippocampus, which may lead to a glial activation. CONCLUSION Our findings suggest that taking care of teeth is very important to preserve a healthy oral environment, which may reduce the risk of cognitive dysfunction.
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Affiliation(s)
- Ferdous Taslima
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Cha-Gyun Jung
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Chunyu Zhou
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Mona Abdelhamid
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Mohammad Abdullah
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Tetsuya Goto
- Department of Oral Anatomy & Cell Biology, Graduate School of Medical and Dental Science, Kagoshima University, Kagoshima, Japan
| | - Takashi Saito
- Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako, Japan
| | - Makoto Michikawa
- Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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Barbe AG, Javadian S, Rott T, Scharfenberg I, Deutscher HCD, Noack MJ, Derman SHM. Objective masticatory efficiency and subjective quality of masticatory function among patients with periodontal disease. J Clin Periodontol 2020; 47:1344-1353. [DOI: 10.1111/jcpe.13364] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/11/2020] [Accepted: 08/27/2020] [Indexed: 12/20/2022]
Affiliation(s)
- Anna Greta Barbe
- Department of Operative Dentistry and Periodontology University of Cologne Cologne Germany
| | - Simin Javadian
- Department of Operative Dentistry and Periodontology University of Cologne Cologne Germany
| | - Thea Rott
- Department of Operative Dentistry and Periodontology University of Cologne Cologne Germany
| | - Isabel Scharfenberg
- Department of Operative Dentistry and Periodontology University of Cologne Cologne Germany
| | | | - Michael Johannes Noack
- Department of Operative Dentistry and Periodontology University of Cologne Cologne Germany
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7
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Association of oral health–related quality of life and Alzheimer disease: A systematic review. J Prosthet Dent 2020; 124:168-175. [DOI: 10.1016/j.prosdent.2019.08.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 08/21/2019] [Accepted: 08/21/2019] [Indexed: 01/07/2023]
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8
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Gür E, Duyan YA, Arkan S, Karson A, Balcı F. Interval timing deficits and their neurobiological correlates in aging mice. Neurobiol Aging 2020; 90:33-42. [PMID: 32220513 DOI: 10.1016/j.neurobiolaging.2020.02.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 01/27/2020] [Accepted: 02/22/2020] [Indexed: 11/24/2022]
Abstract
Age-related neurobiological and cognitive alterations suggest that interval timing (as a related function) is also altered in aging, which can, in turn, disrupt timing-dependent functions. We investigated alterations in interval timing with aging and accompanying neurobiological changes. We tested 4-6, 10-12, and 18-20 month-old mice on the dual peak interval procedure. Results revealed a specific deficit in the termination of timed responses (stop-times). The decision processes contributed more to timing variability (vs. clock/memory process) in the aged mice. We observed age-dependent reductions in the number of dopaminergic neurons in the VTA and SNc, cholinergic neurons in the medial septum/diagonal band (MS/DB) complex, and density of dopaminergic axon terminals in the DLS/DMS. Negative correlations were found between the number of dopaminergic neurons in the VTA and stop times, and the number of cholinergic neurons in MS/DB complex and the acquisition of stop times. Our results point at age-dependent changes in the decisional components of interval timing and the role of dopaminergic and cholinergic functions in these behavioral alterations.
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Affiliation(s)
- Ezgi Gür
- Timing and Decision-Making Laboratory, Department of Psychology, Koç University, Istanbul, Turkey; Koç University Research Center for Translational Medicine, Istanbul, Turkey
| | - Yalçın Akın Duyan
- Timing and Decision-Making Laboratory, Department of Psychology, Koç University, Istanbul, Turkey; Koç University Research Center for Translational Medicine, Istanbul, Turkey
| | - Sertan Arkan
- Timing and Decision-Making Laboratory, Department of Psychology, Koç University, Istanbul, Turkey; Koç University Research Center for Translational Medicine, Istanbul, Turkey; Kocaeli University, Physiology Department, Umuttepe Campus, Kocaeli, Turkey
| | - Ayşe Karson
- Kocaeli University, Physiology Department, Umuttepe Campus, Kocaeli, Turkey
| | - Fuat Balcı
- Timing and Decision-Making Laboratory, Department of Psychology, Koç University, Istanbul, Turkey; Koç University Research Center for Translational Medicine, Istanbul, Turkey.
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Pang Q, Wu Q, Hu X, Zhang J, Jiang Q. Tooth loss, cognitive impairment and chronic cerebral ischemia. J Dent Sci 2020; 15:84-91. [PMID: 32257004 PMCID: PMC7109480 DOI: 10.1016/j.jds.2019.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 08/28/2019] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND/PURPOSE Vascular factor is an important risk factor in the process of cognitive impairment or dementia. Tooth loss could cause impairments of spatial learning and memory in mice, and nitric oxide (NO) and its synthase might be involved in the process. The objectives of this study were to investigate and compare the behavioral impairments between the Wistar rats with tooth loss and those with chronic ischemia and to determine the changes in nitric oxide (NO) and its synthases under those two conditions. MATERIALS AND METHODS The Morris water maze was used to test the spatial learning and memory abilities in the Wistar rats 8 weeks after the molar extraction procedure and the occlusion of 2 blood vessels to produce cerebral ischemia. The changes in NO and its synthases were evaluated using the Griess assay, Western blotting, and immunohistochemistry. RESULTS Similar impairments in the spatial learning and memory of Wistar rats were found after tooth loss and the induction of cerebral ischemia. The levels of NO and iNOS in the rat hippocampus increased, and the levels of eNOS decreased. Conclusion: For Wistar rats, the results of cognitive impairments related to tooth loss and those that occur due to chronic cerebral ischemia were statistically not significant and that NO, iNOS and eNOS in the hippocampus are involved in both cases.
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Affiliation(s)
- Qian Pang
- Department of Prosthodontics, Beijing Stomatology Hospital and School of Stomatology, Capital Medical University, Beijing, 100050, China
| | - Qianqian Wu
- Department of Stomatology, People's Hospital of Beijing Daxing District, Capital Medical University, Beijing, 102600, China
| | - Xingxue Hu
- Division of Restorative, Prosthetic and Primary Care Dentistry, College of Dentistry, Ohio State University, OH, 43210, USA
- Dental 28, Lexington, MA, 02420, USA
| | - Jianjun Zhang
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Qingsong Jiang
- Department of Prosthodontics, Beijing Stomatology Hospital and School of Stomatology, Capital Medical University, Beijing, 100050, China
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Impact of Tooth Loss and Other Risk Factors on Cognitive Impairment in Saudi Female Population. NEUROSCIENCE JOURNAL 2019; 2019:6086515. [PMID: 31428623 PMCID: PMC6681579 DOI: 10.1155/2019/6086515] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 05/28/2019] [Accepted: 07/07/2019] [Indexed: 11/17/2022]
Abstract
Introduction It is known that cognitive impairment is linked to aging and neurobiological, psychological, and social factors. Recently, however, mastication and the number of teeth has also attracted attention, with a previous case control study reporting a correlation between the loss of teeth and Alzheimer's disease. Objective To investigate possible relationships between cognitive function and various demographic variables, stress, medical history, and number of natural teeth in a specified female population. Materials & Methods A sample of the Saudi female population, 40-65 years of age, who visited the King Khalid University College of Dentistry (Abha, Saudi Arabia), was studied. Education, occupation, perceived stress, and medical history, along with the number of remaining teeth, were assessed. The Mini-Mental State Examination (MMSE) was used to assess cognitive performance and the results were statistically analyzed. Results Subjects were divided into those with mild, moderate, and severe impairment based on MMSE score; the association between age, education, occupation, medical history, and cognitive function demonstrated statistically significant results. Fifty percent of subjects with 0-16 teeth exhibited severe cognitive impairment. Of the cognitive abilities, attention, recall, and language skills were linked to the number of remaining teeth. When subjects were categorized into only high and low cognitive impairment based on MMSE score, regression analysis did not reveal a significant correlation between any of the studied variables and cognitive impairment. Conclusion Results of the present study add to the recent data and head towards the theory of likely connection between the number of teeth and hippocampus-dependent cognitive functioning. Results of regression analysis revealed an absence of conclusive relation in the latter part of study. Longitudinal analyses including comprehensive clinical dental data with brain-imaging will shed further light on probable causal relationship(s).
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Sessle BJ. Can you be too old for oral implants? An update on ageing and plasticity in the oro‐facial sensorimotor system. J Oral Rehabil 2019; 46:936-951. [DOI: 10.1111/joor.12830] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 05/06/2019] [Accepted: 05/26/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Barry J. Sessle
- Faculty of Dentistry University of Toronto Toronto Ontario Canada
- Department of Physiology, Faculty of Medicine University of Toronto Toronto Ontario Canada
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12
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Kurozumi A, Hara T, Sakamoto S, Araki D, Iida-Tamada S, Kuroda-Ishimine C, Minagi S. Effects of the loss and reconstruction of molar occlusal support on memory retrieval and hippocampal neuron density in rats. J Prosthodont Res 2019; 63:283-287. [PMID: 30686619 DOI: 10.1016/j.jpor.2018.12.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 12/07/2018] [Accepted: 12/19/2018] [Indexed: 11/17/2022]
Abstract
PURPOSE Animal experiments have shown that the loss of occlusal support causes impairments in spatial cognition. Many reports have focused on the memory encoding process, and only few studies have investigated the effect on memory retrieval. This study aimed to examine the effects of both the loss and reconstruction of occlusal support on the memory retrieval process and on the number of hippocampal pyramidal cells. METHODS The experimental animals were divided into a molarless group, in which molars were extracted, a denture-wearing molarless group with experimental dentures inserted after molar extraction, and a control group. Radial maze trials were performed for 20 consecutive days (acquisition phase). The rats were tested on long-term memory retention following the acquisition phase in eight trials every five days, and in an additional trial 20 days later (probe phase). RESULTS The denture-wearing molarless group showed higher levels of spatial learning and memory than the molarless group. There were no significant differences in memory retrieval during the probe phase between the denture-wearing molarless and the control group. The molarless group showed significantly worse spatial learning and memory and had fewer neurons in the hippocampus than the control group. CONCLUSIONS Our results suggest that the loss of occlusal support decreases the number of pyramidal cells in the hippocampus and impairs memory decoding and retrieval. However, this effect is suppressed by the reconstruction of occlusal support.
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Affiliation(s)
- Akimasa Kurozumi
- Occlusion and Removable Prosthodontics, Okayama University Hospital, Okayama, Japan
| | - Tetsuya Hara
- Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
| | - Shunichi Sakamoto
- Occlusion and Removable Prosthodontics, Okayama University Hospital, Okayama, Japan
| | - Daisuke Araki
- Occlusion and Removable Prosthodontics, Okayama University Hospital, Okayama, Japan
| | - Sachiyo Iida-Tamada
- Occlusion and Removable Prosthodontics, Okayama University Hospital, Okayama, Japan
| | | | - Shogo Minagi
- Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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Jou YT. Dental deafferentation and brain damage: A review and a hypothesis. Kaohsiung J Med Sci 2018; 34:231-237. [PMID: 29655412 DOI: 10.1016/j.kjms.2018.01.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 12/07/2017] [Accepted: 01/12/2018] [Indexed: 01/04/2023] Open
Abstract
In the last few decades, neurobiological and human brain imaging research have greatly advanced our understanding of brain mechanisms that support perception and memory, as well as their function in daily activities. Knowledge of the neurobiological mechanisms behind the deafferentation of stomatognathic systems has also expanded greatly in recent decades. In particular, current studies reveal that the peripheral deafferentations of stomatognathic systems may be projected globally into the central nervous system (CNS) and become an associated critical factor in triggering and aggravating neurodegenerative diseases. This review explores basic neurobiological mechanisms associated with the deafferentation of stomatognathic systems. Further included is a discussion on tooth loss and other dental deafferentation (DD) mechanisms, with a focus on dental and masticatory apparatuses associated with brain functions and which may underlie the changes observed in the aging brain. A new hypothesis is presented where DD and changes in the functionality of teeth and the masticatory apparatus may cause brain damage as a result of altered cerebral circulation and dysfunctional homeostasis. Furthermore, multiple recurrent reorganizations of the brain may be a triggering or contributing risk factor in the onset and progression of neurodegenerative conditions such as Alzheimer's disease (AD). A growing understanding of the association between DD and brain aging may lead to solutions in treating and preventing cognitive decline and neurodegenerative diseases.
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Affiliation(s)
- Yi-Tai Jou
- Department of Endodontics School of Dental Medicine University of Pennsylvania Philadelphia, Pennsylvania, USA.
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14
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Kumar A, Kothari M, Grigoriadis A, Trulsson M, Svensson P. Bite or brain: Implication of sensorimotor regulation and neuroplasticity in oral rehabilitation procedures. J Oral Rehabil 2018; 45:323-333. [DOI: 10.1111/joor.12603] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2017] [Indexed: 02/04/2023]
Affiliation(s)
- A. Kumar
- Division of Oral Diagnostics and Rehabilitation; Department of Dental Medicine; Karolinska Institutet; Huddinge Sweden
- Scandinavian Center for Orofacial Neurosciences (SCON); Huddinge Sweden
| | - M. Kothari
- Hammel Neurorehabilitation Centre and University Research Clinic; Aarhus University; Hammel Denmark
| | - A. Grigoriadis
- Division of Oral Diagnostics and Rehabilitation; Department of Dental Medicine; Karolinska Institutet; Huddinge Sweden
- Scandinavian Center for Orofacial Neurosciences (SCON); Huddinge Sweden
| | - M. Trulsson
- Division of Oral Diagnostics and Rehabilitation; Department of Dental Medicine; Karolinska Institutet; Huddinge Sweden
- Scandinavian Center for Orofacial Neurosciences (SCON); Huddinge Sweden
| | - P. Svensson
- Division of Oral Diagnostics and Rehabilitation; Department of Dental Medicine; Karolinska Institutet; Huddinge Sweden
- Scandinavian Center for Orofacial Neurosciences (SCON); Huddinge Sweden
- Section of Orofacial Pain and Jaw Function; Institute for Odontology and Oral Health; Aarhus University; Aarhus Denmark
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15
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The Effect of Number of Teeth and Chewing Ability on Cognitive Function of Elderly in UAE: A Pilot Study. Int J Dent 2017; 2017:5732748. [PMID: 29348749 PMCID: PMC5734010 DOI: 10.1155/2017/5732748] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/16/2017] [Accepted: 09/24/2017] [Indexed: 12/31/2022] Open
Abstract
Cognitive decline is one of the major causes of disability among the aging population. The aim of this study was to explore the relationship between oral health parameters (number of teeth, chewing ability, and presence of a denture) and cognitive function in the elderly across the UAE. Fifty persons (age ≥ 60; 71.26 ± 10.23) were enrolled in the study. Cognitive status was assessed using the standardized mini-mental state examination (SMMSE) and accordingly, cognitively normal subjects scoring ≥24 were considered as the control group and cognitively impaired individuals scoring ≤23 were considered as the low scoring group. Chewing ability was examined, number of teeth was noted, and demographical data was collected. The results of this pilot study showed that individuals with low SMMSE scores were significantly less educated (P < 0.01) and had fewer number of remaining teeth (P < 0.05) and impaired chewing ability (P < 0.05). These results demonstrate a significant link between the number of teeth, chewing ability, and cognitive function. However, this pilot study had its limitations and was the first of its kind in the UAE and Gulf region; therefore, future research addressing the limitations is needed to further explore this association.
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16
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Association between Mastication, the Hippocampus, and the HPA Axis: A Comprehensive Review. Int J Mol Sci 2017; 18:ijms18081687. [PMID: 28771175 PMCID: PMC5578077 DOI: 10.3390/ijms18081687] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 07/31/2017] [Accepted: 08/01/2017] [Indexed: 12/29/2022] Open
Abstract
Mastication is mainly involved in food intake and nutrient digestion with the aid of teeth. Mastication is also important for preserving and promoting general health, including hippocampus-dependent cognition. Both animal and human studies indicate that mastication influences hippocampal functions through the end product of the hypothalamic-pituitary-adrenal (HPA) axis, glucocorticoid (GC). Epidemiologic studies suggest that masticatory dysfunction in aged individuals, such as that resulting from tooth loss and periodontitis, acting as a source of chronic stress, activates the HPA axis, leading to increases in circulating GCs and eventually inducing various physical and psychological diseases, such as cognitive impairment, cardiovascular disorders, and osteoporosis. Recent studies demonstrated that masticatory stimulation or chewing during stressful conditions suppresses the hyperactivity of the HPA axis via GCs and GC receptors within the hippocampus, and ameliorates chronic stress-induced hippocampus-dependent cognitive deficits. Here, we provide a comprehensive overview of current research regarding the association between mastication, the hippocampus, and HPA axis activity. We also discuss several potential molecular mechanisms involved in the interactions between mastication, hippocampal function, and HPA axis activity.
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17
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Kubo KY, Murabayashi C, Kotachi M, Suzuki A, Mori D, Sato Y, Onozuka M, Azuma K, Iinuma M. Tooth loss early in life suppresses neurogenesis and synaptophysin expression in the hippocampus and impairs learning in mice. Arch Oral Biol 2017; 74:21-27. [DOI: 10.1016/j.archoralbio.2016.11.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 11/01/2016] [Accepted: 11/03/2016] [Indexed: 11/25/2022]
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18
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Cerutti-Kopplin D, Feine J, Padilha D, de Souza R, Ahmadi M, Rompré P, Booij L, Emami E. Tooth Loss Increases the Risk of Diminished Cognitive Function. JDR Clin Trans Res 2016; 1:10-19. [DOI: 10.1177/2380084416633102] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Emerging evidence suggests that oral health is associated with cognitive function. This review aims to systematically assess this association in adult populations via prospective cohort study designs. Eligible study reports were identified by searching the MEDLINE (via Ovoid), EMBASE, PsycoINFO, and Cochrane Library databases. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated with a random effects model. From 1,251 identified articles, 10 were included in the systematic review and 8 in the meta-analysis. Random effects analysis showed, with statistically low heterogeneity, that individuals with suboptimal dentition (<20 teeth) were at a 20% higher risk for developing cognitive decline (HR = 1.26, 95% CI = 1.14 to 1.40) and dementia (HR = 1.22, 95% CI = 1.04 to 1.43) than those with optimal dentition (≥20 teeth). Studies on the association between periodontal disease and cognitive status showed conflicting results. Within the limits of the quality of published evidence, this meta-analysis lends further support to the hypothesis that tooth loss is associated with an increased risk of cognitive impairment and dementia. Knowledge Transfer Statement: Based on the published literature, the results of this study show that the risk for cognitive impairment and dementia increases with loss of teeth. This information adds to the evidence showing links between oral and general health and suggests that oral health strategies aimed to preserve teeth may be important in reducing risk of systemic disease.
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Affiliation(s)
- D. Cerutti-Kopplin
- Department of Dental Public Health, Faculty of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - J. Feine
- Oral Health Society Research Unit, Faculty of Dentistry, McGill University, Montreal, Canada
| | - D.M. Padilha
- Department of Dental Public Health, Faculty of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - R.F. de Souza
- Department of Dental Materials and Prosthetic Dentistry, Faculty of Dentistry of Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - M. Ahmadi
- Department of Restorative Dentistry, Faculty of Dentistry, Université de Montréal, Montréal, Canada
| | - P. Rompré
- Department of Restorative Dentistry, Faculty of Dentistry, Université de Montréal, Montréal, Canada
| | - L. Booij
- Department of Psychology, Queen’s University, Kingston, Canada
| | - E. Emami
- Department of Restorative Dentistry, Faculty of Dentistry, Université de Montréal, Montréal, Canada
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19
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Chronic Powder Diet After Weaning Induces Sleep, Behavioral, Neuroanatomical, and Neurophysiological Changes in Mice. PLoS One 2015; 10:e0143909. [PMID: 26630494 PMCID: PMC4668096 DOI: 10.1371/journal.pone.0143909] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/11/2015] [Indexed: 12/23/2022] Open
Abstract
The purpose of this study is to clarify the effects of chronic powder diet feeding on sleep patterns and other physiological/anatomical changes in mice. C57BL/6 male mice were divided into two groups from weaning: a group fed with solid food (SD) and a group fed with powder food (PD), and sleep and physiological and anatomical changes were compared between the groups. PD exhibited less cranial bone structure development and a significant weight gain. Furthermore, these PD mice showed reduced number of neurogenesis in the hippocampus. Sleep analysis showed that PD induced attenuated diurnal sleep/wake rhythm, characterized by increased sleep during active period and decreased sleep during rest period. With food deprivation (FD), PD showed less enhancement of wake/locomotor activity compared to SD, indicating reduced food-seeking behavior during FD. These results suggest that powder feeding in mice results in a cluster of detrimental symptoms caused by abnormal energy metabolism and anatomical/neurological changes.
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20
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Iwasaki M, Kimura Y, Yoshihara A, Ogawa H, Yamaga T, Sato M, Wada T, Sakamoto R, Ishimoto Y, Fukutomi E, Chen W, Imai H, Fujisawa M, Okumiya K, Taylor GW, Ansai T, Miyazaki H, Matsubayashi K. Oral health status in relation to cognitive function among older Japanese. Clin Exp Dent Res 2015; 1:3-9. [PMID: 29744134 PMCID: PMC5839238 DOI: 10.1002/cre2.2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 03/31/2015] [Accepted: 04/01/2015] [Indexed: 12/25/2022] Open
Abstract
Epidemiologic data examining the relationship between oral health status and cognitive status are sparse, especially in Asian populations. This study aimed to assess whether periodontal disease and tooth loss were related to cognitive impairment among older Japanese. Study participants were 291 Japanese (101 men and 190 women, average age: 80.9 years), classified into three groups based on a clinical examination of oral health status: no periodontal disease, periodontal disease, and edentulous. Periodontal disease was defined using criteria recommended in the consensus report of the European Workshop in Periodontology with a modification. Cognitive impairment was defined using the results of the Mini-mental State Examination (MMSE) and Hasegawa Dementia Scale-Revised (HDS-R) scores. Multivariable logistic regression analyses assessed the relationship of the three-category oral health status variable (reference category = no periodontal disease) with low MMSE score (≤23) and low HDS-R score (≤20). Age, gender, years of education, body mass index, smoking status, drinking behavior, and history of cardiovascular disease were tested as potential confounders in the multivariable models. Periodontal disease and edentulous were significantly associated with greater odds of low cognitive performance after controlling for potential confounders. The multivariable adjusted odds ratios (ORs) (95% confidence intervals [CIs]) for low MMSE score associated with periodontal disease and edentulous were 2.21 (1.01-4.84) and 2.28 (1.06-4.90), respectively. The multivariable adjusted ORs (95% CIs) for low HDS-R score associated with periodontal disease and edentulous were 4.85 (1.29-18.15) and 3.86 (1.05-14.20), respectively. Poor oral health status was significantly associated with cognitive impairment among community-dwelling older Japanese. Additional well-controlled longitudinal studies are needed to elucidate whether there may be a possible cause-and-effect relationship between oral health status and cognitive function.
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Affiliation(s)
- Masanori Iwasaki
- Division of Preventive Dentistry, Department of Oral Health ScienceNiigata University Graduate School of Medical and Dental SciencesNiigataJapan
- Division of Community Oral Health DevelopmentKyushu Dental UniversityKitakyushuJapan
| | - Yumi Kimura
- Center for Southeast Asian StudiesKyoto UniversityKyotoJapan
| | - Akihiro Yoshihara
- Division of Oral Science for Health Promotion, Department of Oral Health and WelfareNiigata University Graduate School of Medical and Dental SciencesNiigataJapan
| | - Hiroshi Ogawa
- Division of Preventive Dentistry, Department of Oral Health ScienceNiigata University Graduate School of Medical and Dental SciencesNiigataJapan
| | - Takayuki Yamaga
- Division of Preventive Dentistry, Department of Oral Health ScienceNiigata University Graduate School of Medical and Dental SciencesNiigataJapan
| | - Misuzu Sato
- Division of Preventive Dentistry, Department of Oral Health ScienceNiigata University Graduate School of Medical and Dental SciencesNiigataJapan
| | - Taizo Wada
- Center for Southeast Asian StudiesKyoto UniversityKyotoJapan
| | - Ryota Sakamoto
- Center for Southeast Asian StudiesKyoto UniversityKyotoJapan
| | - Yasuko Ishimoto
- Center for Southeast Asian StudiesKyoto UniversityKyotoJapan
| | - Eriko Fukutomi
- Center for Southeast Asian StudiesKyoto UniversityKyotoJapan
| | - Wenling Chen
- Department of Field Medicine, School of Public HealthKyoto UniversityKyotoJapan
| | - Hissei Imai
- Department of Field Medicine, School of Public HealthKyoto UniversityKyotoJapan
| | | | | | - George W. Taylor
- Department of Preventive and Restorative Dental SciencesUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Toshihiro Ansai
- Division of Community Oral Health DevelopmentKyushu Dental UniversityKitakyushuJapan
| | - Hideo Miyazaki
- Division of Preventive Dentistry, Department of Oral Health ScienceNiigata University Graduate School of Medical and Dental SciencesNiigataJapan
| | - Kozo Matsubayashi
- Center for Southeast Asian StudiesKyoto UniversityKyotoJapan
- Department of Field Medicine, School of Public HealthKyoto UniversityKyotoJapan
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21
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He Y, Zhu J, Huang F, Qin L, Fan W, He H. Age-dependent loss of cholinergic neurons in learning and memory-related brain regions and impaired learning in SAMP8 mice with trigeminal nerve damage. Neural Regen Res 2015; 9:1985-94. [PMID: 25598781 PMCID: PMC4283282 DOI: 10.4103/1673-5374.145380] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2014] [Indexed: 11/04/2022] Open
Abstract
The tooth belongs to the trigeminal sensory pathway. Dental damage has been associated with impairments in the central nervous system that may be mediated by injury to the trigeminal nerve. In the present study, we investigated the effects of damage to the inferior alveolar nerve, an important peripheral nerve in the trigeminal sensory pathway, on learning and memory behaviors and structural changes in related brain regions, in a mouse model of Alzheimer's disease. Inferior alveolar nerve transection or sham surgery was performed in middle-aged (4-month-old) or elderly (7-month-old) senescence-accelerated mouse prone 8 (SAMP8) mice. When the middle-aged mice reached 8 months (middle-aged group 1) or 11 months (middle-aged group 2), and the elderly group reached 11 months, step-down passive avoidance and Y-maze tests of learning and memory were performed, and the cholinergic system was examined in the hippocampus (Nissl staining and acetylcholinesterase histochemistry) and basal forebrain (choline acetyltransferase immunohistochemistry). In the elderly group, animals that underwent nerve transection had fewer pyramidal neurons in the hippocampal CA1 and CA3 regions, fewer cholinergic fibers in the CA1 and dentate gyrus, and fewer cholinergic neurons in the medial septal nucleus and vertical limb of the diagonal band, compared with sham-operated animals, as well as showing impairments in learning and memory. Conversely, no significant differences in histology or behavior were observed between middle-aged group 1 or group 2 transected mice and age-matched sham-operated mice. The present findings suggest that trigeminal nerve damage in old age, but not middle age, can induce degeneration of the septal-hippocampal cholinergic system and loss of hippocampal pyramidal neurons, and ultimately impair learning ability. Our results highlight the importance of active treatment of trigeminal nerve damage in elderly patients and those with Alzheimer's disease, and indicate that tooth extraction should be avoided in these populations.
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Affiliation(s)
- Yifan He
- Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong Province, China
| | - Jihong Zhu
- Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong Province, China ; Huaihe Hospital, Henan University, Kaifeng, Henan Province, China
| | - Fang Huang
- Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong Province, China
| | - Liu Qin
- Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong Province, China
| | - Wenguo Fan
- Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong Province, China
| | - Hongwen He
- Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong Province, China
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Chen H, Iinuma M, Onozuka M, Kubo KY. Chewing Maintains Hippocampus-Dependent Cognitive Function. Int J Med Sci 2015; 12:502-9. [PMID: 26078711 PMCID: PMC4466515 DOI: 10.7150/ijms.11911] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/25/2015] [Indexed: 02/07/2023] Open
Abstract
Mastication (chewing) is important not only for food intake, but also for preserving and promoting the general health. Recent studies have showed that mastication helps to maintain cognitive functions in the hippocampus, a central nervous system region vital for spatial memory and learning. The purpose of this paper is to review the recent progress of the association between mastication and the hippocampus-dependent cognitive function. There are multiple neural circuits connecting the masticatory organs and the hippocampus. Both animal and human studies indicated that cognitive functioning is influenced by mastication. Masticatory dysfunction is associated with the hippocampal morphological impairments and the hippocampus-dependent spatial memory deficits, especially in elderly. Mastication is an effective behavior for maintaining the hippocampus-dependent cognitive performance, which deteriorates with aging. Therefore, chewing may represent a useful approach in preserving and promoting the hippocampus-dependent cognitive function in older people. We also discussed several possible mechanisms involved in the interaction between mastication and the hippocampal neurogenesis and the future directions for this unique fascinating research.
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Affiliation(s)
- Huayue Chen
- 1. Department of Anatomy Gifu University Graduate School of Medicine, Gifu, 501-1194, Gifu, Japan
| | - Mitsuo Iinuma
- 2. Department of Pediatric Dentistry, Division of Oral Structure, Function and Development, Asahi University, School of Dentistry, Mizuho, 501-0296, Gifu, Japan
| | - Minoru Onozuka
- 3. Department of Judo Therapy and Medical Science, Faculty of Medical Science, Nippon Sport Science University, Yokohama 227-0033, Kanagawa, Japan
| | - Kin-Ya Kubo
- 4. Seijoh University Graduate School of Health Care Studies, Tokai, 476-8588, Aichi, Japan
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23
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Pang Q, Hu X, Li X, Zhang J, Jiang Q. Behavioral impairments and changes of nitric oxide and inducible nitric oxide synthase in the brains of molarless KM mice. Behav Brain Res 2014; 278:411-6. [PMID: 25447296 DOI: 10.1016/j.bbr.2014.10.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 10/14/2014] [Accepted: 10/17/2014] [Indexed: 01/24/2023]
Abstract
More studies showed that as a common disorder in senior population, loss of teeth could adversely affect human cognitive function, and nitric oxide (NO) might play an important role in the cognitive function. However, the underlying mechanism has not yet been well-established. The objectives of this study are to evaluate behavior changes of KM mice after loss of molars, and levels of NO and inducible nitric oxide synthase (iNOS) in the brain in molarless condition. It is hypothesized that loss of molars of the mice tested results in the cognitive impairments and that the process is mediated by NO in the brain through the signaling pathways. Morris water maze is used to test the behavioral changes after 8 weeks of the surgery. The changes of NO and iNOS are evaluated by using Griess assay, western blot, and immunohistochemistry method. The results show that 8 weeks after loss of molars, the spatial learning and memory of KM mice impair and the levels of NO and iNOS in mice hippocampus increase. These findings suggest that molar extraction is associated with the behavioral impairment, and that the changes of NO and iNOS in the hippocampus may be involved in the behavioral changes in the molarless condition.
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Affiliation(s)
- Qian Pang
- Department of Prosthodontics, Beijing Stomatology Hospital and School of Stomatology, Capital Medical University, Beijing 100050, China
| | - Xingxue Hu
- Advanced Standing Program, Boston University Henry M. Goldman School of Dental Medicine, 100 East Newton Street, Boston, MA 02118, USA
| | - Xinya Li
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Jianjun Zhang
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Qingsong Jiang
- Department of Prosthodontics, Beijing Stomatology Hospital and School of Stomatology, Capital Medical University, Beijing 100050, China.
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24
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Sakamoto S, Hara T, Kurozumi A, Oka M, Kuroda-Ishimine C, Araki D, Iida S, Minagi S. Effect of occlusal rehabilitation on spatial memory and hippocampal neurons after long-term loss of molars in rats. J Oral Rehabil 2014; 41:715-22. [PMID: 24909970 DOI: 10.1111/joor.12198] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2014] [Indexed: 11/28/2022]
Abstract
Experimental loss of occlusal support caused by the extraction or grinding of molar teeth has been reported to foment the impairment of learning and memory in laboratory animals. The purpose of this study was to examine the effect of occlusal reconstruction after long-term loss of molars on spatial memory by using 8-arm radial maze and by assessing histopathological changes of neuron density in the hippocampus. Experimental dentures were inserted into the oral cavities of molarless rats to recover the occlusal support. Age-matched groups of control, molarless and denture-wearing rats were trained to perform the maze tasks. The difference of the error incidence in the maze task was evaluated between three groups. The difference of neuron density between three groups was also evaluated at the end of the maze task. Serum corticosterone levels were also measured to estimate the chronic stress, which could be caused by extraction, insertion of the experimental denture or any experimental procedure. The error incidence in the denture-wearing group was significantly higher than that of the control group, but significantly lower than that of the molarless group. Significant differences of neuron density were observed between three groups in each of the hippocampal CA1, CA3 and DG subfields. No significant difference of the serum corticosterone levels between three groups could be observed. From the results of this study, it was suggested that the recovery of occlusal support would bring amelioration of cognitive impairment concomitant with long period loss of molars in rats.
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Affiliation(s)
- S Sakamoto
- Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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25
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Teixeira FB, Pereira Fernandes LDM, Noronha PAT, dos Santos MAR, Gomes-Leal W, Ferraz Maia CDS, Lima RR. Masticatory deficiency as a risk factor for cognitive dysfunction. Int J Med Sci 2014; 11:209-14. [PMID: 24465167 PMCID: PMC3894406 DOI: 10.7150/ijms.6801] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 11/25/2013] [Indexed: 11/13/2022] Open
Abstract
Several studies have demonstrated that chewing helps to maintain cognitive functions in brain regions including the hippocampus, a central nervous system (CNS) region vital for memory and learning. Epidemiological studies suggest that masticatory deficiency is associated with development of dementia, which is related to spatial memory deficits especially in older animals. The purpose of this paper is to review recent work on the effects of masticatory impairment on cognitive functions both in experimental animals and humans. We show that several mechanisms may be involved in the cognitive deficits associated with masticatory deficiency. The epidemiological data suggest a positive correlation between masticatory deficit and Alzheimer's disease. It may be concluded that chewing has important implications for the mechanisms underlying certain cognitive abilities.
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Affiliation(s)
- Francisco Bruno Teixeira
- 1. Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, 66075-900, Belém-Pará, Brazil
| | - Luanna de Melo Pereira Fernandes
- 1. Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, 66075-900, Belém-Pará, Brazil; ; 2. Laboratory Pharmacology of Inflammation and Behavior, Institute of Health Sciences, Federal University of Pará, 66075-900, Belém-Pará, Brazil
| | - Patrycy Assis Tavares Noronha
- 3. Laboratory of Experimental Neuroprotection and Neuroregeneration, Institute of Biological Sciences, Federal University of Pará, 66075-900, Belém-Pará, Brazil
| | - Marcio Antonio Raiol dos Santos
- 1. Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, 66075-900, Belém-Pará, Brazil
| | - Walace Gomes-Leal
- 3. Laboratory of Experimental Neuroprotection and Neuroregeneration, Institute of Biological Sciences, Federal University of Pará, 66075-900, Belém-Pará, Brazil
| | - Cristiane do Socorro Ferraz Maia
- 2. Laboratory Pharmacology of Inflammation and Behavior, Institute of Health Sciences, Federal University of Pará, 66075-900, Belém-Pará, Brazil
| | - Rafael Rodrigues Lima
- 1. Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, 66075-900, Belém-Pará, Brazil
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26
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Elsig F, Schimmel M, Duvernay E, Giannelli SV, Graf CE, Carlier S, Herrmann FR, Michel JP, Gold G, Zekry D, Müller F. Tooth loss, chewing efficiency and cognitive impairment in geriatric patients. Gerodontology 2013; 32:149-56. [PMID: 24128078 DOI: 10.1111/ger.12079] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2013] [Indexed: 11/26/2022]
Abstract
BACKGROUND Patients with dementia have poorer oral health and fewer teeth than their peers without cognitive impairment. OBJECTIVE The hypothesis of this study is that the number of natural teeth and the chewing efficiency are associated with cognitive functioning. METHODS This cross-sectional study included 29 patients diagnosed with dementia aged 75 years or older and 22 controls who were either cognitively normal (n = 19) or with mild cognitive impairment (n = 3). Neuropsychological, nutritional and dental assessments were performed. The chewing efficiency was evaluated with a two-colour mixing test. RESULTS Demented patients and controls presented with a mean of 4.9 and 6.5 teeth, respectively (n.s.). The number of natural teeth was not associated with dementia (p = 0.553). Same results were found for age (p = 0.746) and sex (p = 0.901). The chewing efficiency by visual inspection proved worse in participants with dementia than in the controls (p < 0.011) and explained 9.3% of the variance in the diagnosis of dementia. Neither dental state nor chewing efficiency was related to the nutritional state. CONCLUSION Chewing efficiency seems stronger associated with cognitive impairment than the number of teeth. Hence, in a more holistic approach for the geriatric assessment, the dental examination may be complemented by a chewing efficiency test.
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Affiliation(s)
- Fanny Elsig
- Division of Gerodontology and Removable Prosthodontics, University of Geneva Dental School, Geneva, Switzerland
| | - Martin Schimmel
- Division of Gerodontology and Removable Prosthodontics, University of Geneva Dental School, Geneva, Switzerland
| | - Elena Duvernay
- Division of Gerodontology and Removable Prosthodontics, University of Geneva Dental School, Geneva, Switzerland
| | - Sandra V Giannelli
- Department of Internal Medicine, Rehabilitation and Geriatrics, University Hospitals Geneva, Thônex, Switzerland
| | - Christoph E Graf
- Department of Internal Medicine, Rehabilitation and Geriatrics, University Hospitals Geneva, Thônex, Switzerland
| | - Sabrina Carlier
- Department of Internal Medicine, Rehabilitation and Geriatrics, University Hospitals Geneva, Thônex, Switzerland
| | - François R Herrmann
- Department of Internal Medicine, Rehabilitation and Geriatrics, University Hospitals Geneva, Thônex, Switzerland
| | - Jean-Pierre Michel
- Department of Internal Medicine, Rehabilitation and Geriatrics, University Hospitals Geneva, Thônex, Switzerland
| | - Gabriel Gold
- Department of Internal Medicine, Rehabilitation and Geriatrics, University Hospitals Geneva, Thônex, Switzerland
| | - Dina Zekry
- Department of Internal Medicine, Rehabilitation and Geriatrics, University Hospitals Geneva, Thônex, Switzerland
| | - Frauke Müller
- Division of Gerodontology and Removable Prosthodontics, University of Geneva Dental School, Geneva, Switzerland.,Department of Internal Medicine, Rehabilitation and Geriatrics, University Hospitals Geneva, Thônex, Switzerland
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27
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Hansson P, Sunnegårdh-Grönberg K, Bergdahl J, Bergdahl M, Nyberg L, Nilsson LG. Relationship between natural teeth and memory in a healthy elderly population. Eur J Oral Sci 2013; 121:333-40. [DOI: 10.1111/eos.12060] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/24/2013] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | - Maud Bergdahl
- Institute of Clinical Dentistry; University of Tromsø; Tromsø; Norway
| | - Lars Nyberg
- Departments of Radiation Sciences and Integrative Medical Biology; Umeå Center for Functional Brain Imaging; Umeå University; Umeå; Sweden
| | - Lars-Göran Nilsson
- Department of Psychology; Stockholm University, and Stockholm Brain Institute; Stockholm; Sweden
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De Cicco V. Cerebro-afferent vessel and pupillary basal diameter variation induced by stomatognathic trigeminal proprioception: a case report. J Med Case Rep 2012; 6:275. [PMID: 22943461 PMCID: PMC3477066 DOI: 10.1186/1752-1947-6-275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Accepted: 03/07/2012] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION A patient affected by asymmetric hemodynamics of cerebro-afferent vessels underwent duplex color scanner investigations in occlusal proprioceptive un- and rebalance conditions. Pupillometric video-oculographic examinations were performed in order to spot connected trigeminal proprioceptive motor patterns able to interfere on sympathetic autonomic activity. The aim of this case report is to verify if involuntary jaw closing during swallowing, executed in unbalance and rebalance myoelectric activity, would be able to modify cerebral hemodynamics. CASE PRESENTATION A 56-year-old Caucasian Italian woman affected by asymmetric blood flow of cerebro-afferent vessels underwent an electromyographic investigation of her occlusal muscles in order to assess their occlusal functional balance. The extreme asymmetry of myoelectric activity in dental occlusion evidenced by electromyographic values suggested the rebalancing of the functions of occlusal muscles through concurrent transcutaneous stimulation of the trigeminal nerve supra- and submandibular motor branches. The above-mentioned method allowed the detection of a symmetric craniomandibular muscular relation that can be kept constant through the use of a cusp bite modeled on the inferior dental arch: called orthotic-syntropic bite for its peculiar use of electrostimulation. A few days later, the patient underwent a duplex color scanner investigation and pupillometric video-oculographic examinations in occlusal unbalance and rebalance conditions. CONCLUSIONS A comparative data analysis showed that an unbalanced dental occlusal function may represent an interferential pattern on cerebral hemodynamics velocity and pupillometric evaluations have proved useful both in the analysis of locus coeruleus functional modalities and as a diagnostic tool in the assessment of pathologies involving locus coeruleus and autonomic systems. The inclusion of myoelectric masseter examinations can be useful in patients with asymmetric hemodynamics of cerebro-afferent vessels and dental occlusal proprioceptive rebalance can integrate the complex therapy of patients with increased chronic sympathetic activity.
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Affiliation(s)
- Vincenzo De Cicco
- Department of Oral Science, University "G, d'Annunzio", via dei Vestini 31, Chieti, 66100, Italy.
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Central syntropic effects elicited by trigeminal proprioceptive equilibrium in Alzheimer's disease: a case report. J Med Case Rep 2012; 6:161. [PMID: 22734831 PMCID: PMC3411437 DOI: 10.1186/1752-1947-6-161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 06/26/2012] [Indexed: 11/13/2022] Open
Abstract
Introduction The presented patient, affected by Alzheimer’s disease, underwent neuropsychological evaluation and functional magnetic resonance imaging investigation under occlusal proprioceptive un-balance and re-balance conditions. Saccadic and pupillometric video-oculographic examinations were performed in order to detect connected trigeminal proprioceptive motor patterns able to interfere with reticular formation cerebellum functions linked to visual and procedural processes prematurely altered in Alzheimer’s disease. Case presentation A 66-year-old Caucasian man, affected by Alzheimer’s disease and with a neuropsychological evaluation issued by the Alzheimer’s Evaluation Unit, underwent an electromyographic investigation of the masseter muscles in order to assess their functional balance. The patient showed a bilateral lack of all inferior molars. The extreme myoelectric asymmetry in dental occlusion suggested the rebalancing of masseter muscular functions through concurrent transcutaneous stimulation of the trigeminal nerve supramandibular and submandibular motor branches. The above-mentioned method allows detection of symmetric craniomandibular muscular relation that can be kept constant through the use of a cusp bite modeled on the inferior dental arch, called orthotic-syntropic bite. A few days later, the patient underwent a new neuropsychological investigation, together with a functional magnetic resonance imaging study, and saccadic, pupillometric video-oculographic examinations in occlusal un-balance and re-balance conditions. Conclusions Comparative data analysis has shown that a re-balanced occlusal condition can improve a patient’s cognitive-attentive functions. Moreover, the saccadic and pupillometric video-oculographic investigations have proven useful both in analyzing reticulo-cerebellar subcortical systems, prematurely altered in Alzheimer’s disease, and in implementing neurological evaluations.
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Takuma K, Mizoguchi H, Funatsu Y, Hoshina Y, Himeno Y, Fukuzaki E, Kitahara Y, Arai S, Ibi D, Kamei H, Matsuda T, Koike K, Inoue M, Nagai T, Yamada K. Combination of chronic stress and ovariectomy causes conditioned fear memory deficits and hippocampal cholinergic neuronal loss in mice. Neuroscience 2012; 207:261-73. [DOI: 10.1016/j.neuroscience.2012.01.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 12/28/2011] [Accepted: 01/17/2012] [Indexed: 11/28/2022]
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31
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Frota de Almeida MN, de Siqueira Mendes FDCC, Gurgel Felício AP, Falsoni M, Ferreira de Andrade ML, Bento-Torres J, da Costa Vasconcelos PF, Perry VH, Picanço-Diniz CW, Kronka Sosthenes MC. Spatial memory decline after masticatory deprivation and aging is associated with altered laminar distribution of CA1 astrocytes. BMC Neurosci 2012; 13:23. [PMID: 22376223 PMCID: PMC3355053 DOI: 10.1186/1471-2202-13-23] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 02/29/2012] [Indexed: 01/27/2023] Open
Abstract
Background Chewing imbalances are associated with neurodegeneration and are risk factors for senile dementia in humans and memory deficits in experimental animals. We investigated the impact of long-term reduced mastication on spatial memory in young, mature and aged female albino Swiss mice by stereological analysis of the laminar distribution of CA1 astrocytes. A soft diet (SD) was used to reduce mastication in the experimental group, whereas the control group was fed a hard diet (HD). Assays were performed in 3-, 6- and 18-month-old SD and HD mice. Results Eating a SD variably affected the number of astrocytes in the CA1 hippocampal field, and SD mice performed worse on water maze memory tests than HD mice. Three-month-old mice in both groups could remember/find a hidden platform in the water maze. However, 6-month-old SD mice, but not HD mice, exhibited significant spatial memory dysfunction. Both SD and HD 18-month-old mice showed spatial memory decline. Older SD mice had astrocyte hyperplasia in the strata pyramidale and oriens compared to 6-month-old mice. Aging induced astrocyte hypoplasia at 18 months in the lacunosum-moleculare layer of HD mice. Conclusions Taken together, these results suggest that the impaired spatial learning and memory induced by masticatory deprivation and aging may be associated with altered astrocyte laminar distribution and number in the CA1 hippocampal field. The underlying molecular mechanisms are unknown and merit further investigation.
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Affiliation(s)
- Marina Negrão Frota de Almeida
- Universidade Federal do Pará-UFPA, Instituto de Ciências Biológicas, Laboratório de Investigações em Neurodegeneração e Infecção, Hospital Universitário João de Barros Barreto, Belém, PA, Brazil
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Ohno A, Yoshino F, Yoshida A, Hori N, Ono Y, Kimoto K, Onozuka M, Lee MCI. Soft-food diet induces oxidative stress in the rat brain. Neurosci Lett 2012; 508:42-6. [DOI: 10.1016/j.neulet.2011.12.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 11/30/2011] [Accepted: 12/12/2011] [Indexed: 10/14/2022]
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Kurata C, Ichihashi Y, Onishi M, Iinuma M, Tamura Y, Mori D, Kubo KY. Early toothless condition suppresses cell proliferation in the hippocampal dentate gyrus of SAMP8 mice. PEDIATRIC DENTAL JOURNAL 2012. [DOI: 10.1016/s0917-2394(12)70261-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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del Valle J, Duran-Vilaregut J, Manich G, Pallàs M, Camins A, Vilaplana J, Pelegrí C. Cerebral amyloid angiopathy, blood-brain barrier disruption and amyloid accumulation in SAMP8 mice. NEURODEGENER DIS 2011; 8:421-9. [PMID: 21411981 DOI: 10.1159/000324757] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 02/01/2011] [Indexed: 01/09/2023] Open
Abstract
Cerebrovascular dysfunction and β-amyloid peptide deposition on the walls of cerebral blood vessels might be an early event in the development of Alzheimer's disease. Here we studied the time course of amyloid deposition in blood vessels and blood-brain barrier (BBB) disruption in the CA1 subzone of the hippocampus of SAMP8 mice and the association between these two variables. We also studied the association between the amyloid deposition in blood vessels and the recently described amyloid clusters in the parenchyma, as well as the association of these clusters with vessels in which the BBB is disrupted. SAMP8 mice showed greater amyloid deposition in blood vessels than age-matched ICR-CD1 control mice. Moreover, at 12 months of age the number of vessels with a disrupted BBB had increased in both strains, especially SAMP8 animals. At this age, all the vessels with amyloid deposition showed BBB disruption, but several capillaries with an altered BBB showed no amyloid on their walls. Moreover, amyloid clusters showed no spatial association with vessels with amyloid deposition, nor with vessels in which the BBB had been disrupted. Finally, we can conclude that vascular amyloid deposition seems to induce BBB alterations, but BBB disruption may also be due to other factors.
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Affiliation(s)
- Jaume del Valle
- Departament de Fisiologia, Facultat de Farmàcia, Barcelona, Spain
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Cheng XR, Yang Y, Zhou WX, Zhang YX. Expression of VGLUTs contributes to degeneration and acquisition of learning and memory. Neurobiol Learn Mem 2011; 95:361-75. [PMID: 21295146 DOI: 10.1016/j.nlm.2011.01.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 01/16/2011] [Accepted: 01/25/2011] [Indexed: 12/27/2022]
Abstract
Vesicular glutamate transporters (VGLUTs), which include VGLUT1, VGLUT2 and VGLUT3, are responsible for the uploading of L-glutamate into synaptic vesicles. The expression pattern of VGLUTs determines the level of synaptic vesicle filling (i.e., glutamate quantal size) and directly influences glutamate receptors and glutamatergic synaptic transmission; thus, VGLUTs may play a key role in learning and memory in the central nervous system. To determine whether VGLUTs contribute to the degeneration or acquisition of learning and memory, we used an animal model for the age-related impairment of learning and memory, senescence-accelerated mouse/prone 8 (SAMP8). KM mice were divided into groups based on their learning and memory performance in a shuttle-box test. The expression of VGLUTs and synaptophysin (Syp) mRNA and protein in the cerebral cortex and hippocampus were investigated with real-time fluorescence quantitative PCR and western blot, respectively. Our results demonstrate that, in the cerebral cortex, protein expression of VGLUT1, VGLUT2, VGLUT3 and Syp was decreased in SAMP8 with age and increased in KM mice, which displayed an enhanced capacity for learning and memory. The protein expression of VGLUT2 and Syp was decreased in the hippocampus of SAMP8 with aging. The expression level of VGLUT1 and VGLUT2 proteins were highest in KM mouse group with a 76-100% avoidance score in the shuttle-box test. These data demonstrate that protein expression of VGLUT1, VGLUT2 and Syp decreases age-dependently in SAMP8 and increases in a learning- and memory-dependent manner in KM mice. Correlation analysis indicated the protein expression of VGLUT1, VGLUT2 and Syp has a positive correlation with the capacity of learning and memory.
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Affiliation(s)
- Xiao-Rui Cheng
- Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China
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Urine formaldehyde level is inversely correlated to mini mental state examination scores in senile dementia. Neurobiol Aging 2011; 32:31-41. [DOI: 10.1016/j.neurobiolaging.2009.07.013] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 07/09/2009] [Accepted: 07/26/2009] [Indexed: 02/02/2023]
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Weijenberg R, Scherder E, Lobbezoo F. Mastication for the mind—The relationship between mastication and cognition in ageing and dementia. Neurosci Biobehav Rev 2011; 35:483-97. [DOI: 10.1016/j.neubiorev.2010.06.002] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 06/05/2010] [Accepted: 06/08/2010] [Indexed: 01/14/2023]
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Kubo KY, Ichihashi Y, Kurata C, Iinuma M, Mori D, Katayama T, Miyake H, Fujiwara S, Tamura Y. Masticatory function and cognitive function. Okajimas Folia Anat Jpn 2010; 87:135-140. [PMID: 21174943 DOI: 10.2535/ofaj.87.135] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Recent studies have suggest that masticatory (chewing) function is useful for maintaining neurocognitive function in the elderly. For example, a reduced ability to masticate, such as that resulting from toothlessness or soft-diet feeding, causes learning and memory deficits in aged animals and pathologic changes in the hippocampus. In addition, occlusal disharmony impairs hippocampal memory processes via chronic stress, and induces similar hippocampal pathology. Chewing, however, rescues stress-induced suppression of long-term potentiation in the hippocampus and the stress-induced impairment of hippocampal-dependent learning. These findings strongly suggest a link between mastication and neurocognitive function.
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Affiliation(s)
- Kin-Ya Kubo
- Seijoh University Graduate School of Health Care Studies, 2-172 Fukinodai, Tokai, Aichi 476-8588, Japan.
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Ono Y, Yamamoto T, Kubo KY, Onozuka M. Occlusion and brain function: mastication as a prevention of cognitive dysfunction. J Oral Rehabil 2010; 37:624-40. [PMID: 20236235 DOI: 10.1111/j.1365-2842.2010.02079.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Research in animals and humans has shown that mastication maintains cognitive function in the hippocampus, a brain area important for learning and memory. Reduced mastication, an epidemiological risk factor for the development of dementia in humans, attenuates spatial memory and causes hippocampal neurons to deteriorate morphologically and functionally, especially in aged animals. Active mastication rescues the stress-attenuated hippocampal memory process in animals and attenuates the perception of stress in humans by suppressing endocrinological and autonomic stress responses. Active mastication further improves the performance of sustained cognitive tasks by increasing the activation of the hippocampus and the prefrontal cortex, the brain regions that are essential for cognitive processing. Abnormal mastication caused by experimental occlusal disharmony in animals produces chronic stress, which in turn suppresses spatial learning ability. The negative correlation between mastication and corticosteroids has raised the hypothesis that the suppression of the hypothalamic-pituitary-adrenal (HPA) axis by masticatory stimulation contributes, in part, to preserving cognitive functions associated with mastication. In the present review, we examine research pertaining to the mastication-induced amelioration of deficits in cognitive function, its possible relationship with the HPA axis, and the neuronal mechanisms that may be involved in this process in the hippocampus.
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Affiliation(s)
- Y Ono
- Department of Physiology and Neuroscience, Kanagawa Dental College, Yokosuka, Japan.
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40
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Kojo A, Yamada K, Kubo KY, Yamashita A, Yamamoto T. Occlusal Disharmony in Mice Transiently Activates Microglia in Hippocampal CA1 Region but Not in Dentate Gyrus. TOHOKU J EXP MED 2010; 221:237-43. [DOI: 10.1620/tjem.221.237] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Akiko Kojo
- Department of Physiology and Neuroscience, Kanagawa Dental College
- Research Center of Brain and Oral Science, Kanagawa Dental College
| | - Kentaro Yamada
- Department of Physiology and Neuroscience, Kanagawa Dental College
- Research Center of Brain and Oral Science, Kanagawa Dental College
| | - Kin-Ya Kubo
- Department of Oral Anatomy, Division of Oral Structure, Function and Development, Asahi University School of Dentistry
| | - Anzu Yamashita
- Research Center of Brain and Oral Science, Kanagawa Dental College
- Department of Human Biology, Kanagawa Dental College
| | - Toshiharu Yamamoto
- Research Center of Brain and Oral Science, Kanagawa Dental College
- Department of Human Biology, Kanagawa Dental College
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Molarless condition suppresses proliferation but not differentiation rates into neurons in the rat dentate gyrus. Neurosci Lett 2009; 469:44-8. [PMID: 19931591 DOI: 10.1016/j.neulet.2009.11.041] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 11/03/2009] [Accepted: 11/17/2009] [Indexed: 11/23/2022]
Abstract
The dentate gyrus (DG) of the hippocampal complex is one of the few areas of the rodent brain where neurogenesis continues throughout adulthood. We investigated the effects of the molarless condition on cell proliferation, rate of differentiation into neurons in the subgranular zone of the DG, and plasma corticosterone levels. The molarless condition decreased cell proliferation in the DG and increased plasma corticosterone levels. Approximately 80% of newly generated cells differentiated into neurons and the remaining 20% of the cells differentiated into astrocytes. These ratios were not significantly different between control and molarless rats. In conclusion, the rates of neurogenesis and gliogenesis in the DG are suppressed by the molarless condition, and this suppression might be associated with the increased corticosteroid levels in molarless subjects.
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Del Valle J, Duran-Vilaregut J, Manich G, Camins A, Pallàs M, Vilaplana J, Pelegrí C. Time-course of blood-brain barrier disruption in senescence-accelerated mouse prone 8 (SAMP8) mice. Int J Dev Neurosci 2008; 27:47-52. [PMID: 18992318 DOI: 10.1016/j.ijdevneu.2008.10.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 09/29/2008] [Accepted: 10/08/2008] [Indexed: 12/16/2022] Open
Abstract
Senescence of the cerebrovascular system and an abnormal function of the blood-brain barrier have been related with Alzheimer's disease. We studied here the time-course of blood-brain barrier disruption in senescence-accelerated mouse prone 8 (SAMP8) mice, which is a murine model of senescence and is also considered a model of Alzheimer's disease. We used a previously described method that allows evaluating blood-brain barrier integrity by observing Evans blue extravasation from brain blood vessels. Three brain regions (cortex, hippocampus and hippocampal fissure) of SAMP8 brains were analyzed at 3, 6, 9, 12 and 15 months of age. Moreover, genetically related senescence-accelerated mouse resistant 1 (SAMR1) and ICR-CD1 mice were studied. Results indicate that Evans blue permeability in SAMP8 and SAMR1 increases from 6 to 15 months in the three studied regions. At 15 months of age, SAMP8 and SAMR1 mice showed higher Evans blue extravasation in CA1 and Fissure than ICR-CD1 mice. Further studies are required to understand the senescence process in SAMR1 mice, as blood-brain barrier alterations in old age have unexpectedly been observed. On the other hand, as blood-brain barrier permeability in SAMP8 mice increases with age, blood-brain barrier alterations may contribute to the cerebral pathology observed in this strain.
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Affiliation(s)
- Jaume Del Valle
- Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n., 08028 Barcelona, Spain
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Oral health and cognitive function in the Third National Health and Nutrition Examination Survey (NHANES III). Psychosom Med 2008; 70:936-41. [PMID: 18842752 DOI: 10.1097/psy.0b013e3181870aec] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVES To investigate the association between oral health and cognitive function in early-, mid-, and late-adult life. METHODS A secondary analysis was carried out of a large, well-characterized community sample (NHANES III). Analyzed variables included three measures of oral health (gingival bleeding, loss of periodontal attachment, loss of teeth) and three measures of cognitive function: the Symbol Digit Substitution Test (SDST), the Serial Digit Learning Test (SDLT) (both in 5138 participants aged 20-59 years), and a Story Recall test (in 1555 participants aged >or=70 years). Other covariates in linear regression models included age, gender, ethnicity, education and poverty, and cardiovascular risk factors. RESULTS Worse scores on all three measures of oral health status were significantly associated with poorer performance on all three measures of cognitive function after adjustment for age. Education was an important confounding factor. However, after full adjustment for all other covariates, gingival bleeding (%) and loss of periodontal attachment (%) remained associated with relative impairment on SDST score (B coefficients both = 0.003), and gingival bleeding was associated with relative impairment on SDLT (B = 0.017). No effect modification by age was observed. CONCLUSIONS Poor oral health is associated with worse cognitive function throughout adult life. This may, in part, be accounted for by early life education and social status. However, the possibility of direct causal pathways requires further investigation.
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Kushida S, Kimoto K, Hori N, Toyoda M, Karasawa N, Yamamoto T, Kojo A, Onozuka M. Soft-diet feeding decreases dopamine release and impairs aversion learning in Alzheimer model rats. Neurosci Lett 2008; 439:208-11. [DOI: 10.1016/j.neulet.2008.05.017] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 05/05/2008] [Accepted: 05/07/2008] [Indexed: 11/26/2022]
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BERGDAHL MAUD, HABIB REZA, BERGDAHL JAN, NYBERG LARS, NILSSON LARSGÖRAN. Natural teeth and cognitive function in humans. Scand J Psychol 2007; 48:557-65. [DOI: 10.1111/j.1467-9450.2007.00610.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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46
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Tsutsui K, Kaku M, Motokawa M, Tohma Y, Kawata T, Fujita T, Kohno S, Ohtani J, Tenjoh K, Nakano M, Kamada H, Tanne K. Influences of reduced masticatory sensory input from soft-diet feeding upon spatial memory/learning ability in mice. ACTA ACUST UNITED AC 2007; 28:1-7. [PMID: 17379951 DOI: 10.2220/biomedres.28.1] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
It has been reported that reduction of masticatory afferent stimulation might influence learning and memory function. In order to clarify the influences of reduced masticatory sensory input on spatial memory/learning ability and neuropathological changes, we conducted the Morris water maze experiment and investigated the number of hippocampal neurons in association with the differences in masticatory afferent stimuli from hard- and soft-diet feeding in mice. The water maze experiment showed no significant difference in learning ability between 180-day-old solid- and powderdiet groups. Meanwhile, the ability was significantly reduced in the 360-day-old powder-diet group as compared with the age-matched solid-diet group. The total number of pyramidal cells in the hippocampal CA1 and CA3 regions was significantly smaller in 360-day-old powder-diet group than in the remaining groups. These results demonstrate that reduction of masticatory afferent stimuli due to long-term soft-diet feeding may induce neuron loss in the hippocampus and reduced memory/learning ability.
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Affiliation(s)
- Keisuke Tsutsui
- Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
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Aoki H, Kimoto K, Hori N, Toyoda M. Cell Proliferation in the Dentate Gyrus of Rat Hippocampus Is Inhibited by Soft Diet Feeding. Gerontology 2005; 51:369-74. [PMID: 16299417 DOI: 10.1159/000088700] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2005] [Accepted: 07/06/2005] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Recently it has become well accepted that neurogenesis occurs in the dentate gyrus of the hippocampus, a region important to memory and learning function in rodents and humans. Reports show that neurogenesis in the hippocampus is regulated by certain factors, such as exposure to an enriched environment, physical activity, aging and stress. The relationship between the change in the task of chewing as one oral environmental factor, and the mechanisms of hippocampal neuron generation are unclear. OBJECTIVE We examined whether cell proliferation varies by chewing tasks with different food textures in the dentate gyrus of the rat hippocampus. METHODS Wistar rats were divided into two groups, one was fed a solid diet, known as the hard-diet feeding group, and the soft-diet feeding group, which was fed a powder diet containing the same components as the solid one for 3, 7, 16 and 24 weeks. Thymidine analog 5-bromo-2'-deoxyuridine (BrdU) was used as a marker of cell proliferation within the dentate gyrus of the hippocampus and olfactory bulb. RESULTS The results of this study indicated that the total number of BrdU-positive cells in the hippocampal dentate gyrus significantly decreased with aging and were significantly fewer in the soft-diet feeding group than in hard-diet feeding group in 7-, 16- and 24-week-old rats after the BrdU injection. The change of BrdU-positive cell expression between soft and hard diets in 3- and 24-week-old rats was not observed in the olfactory bulb. CONCLUSION It has been suggested that cell proliferation in the dentate gyrus of the rat hippocampus is characteristically suppressed by soft diet feeding.
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Affiliation(s)
- Hiromichi Aoki
- Department of Oral and Maxillofacial Rehabilitation, Kanagawa Dental College, Yokosuka, Kanagawa, Japan
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Kubo KY, Iwaku F, Watanabe K, Fujita M, Onozuka M. Molarless-induced changes of spines in hippocampal region of SAMP8 mice. Brain Res 2005; 1057:191-5. [PMID: 16112090 DOI: 10.1016/j.brainres.2005.07.038] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Revised: 07/15/2005] [Accepted: 07/18/2005] [Indexed: 10/25/2022]
Abstract
We examined the effect of the molarless condition on the dendritic spines of hippocampal pyramidal cells in SAMP8 mice in comparison to its effect on learning ability in a maze test. The molarless condition caused a decrease in the number of the spines of CA1 pyramidal cells only in the aged mice showing a reduced learning ability. The results suggest the involvement of the molarless condition in an attenuation of input activities in the hippocampal synapses.
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Affiliation(s)
- Kin-Ya Kubo
- Department of Oral Anatomy, Division of Oral Structure, Function and Development, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu 501-0296, Japan.
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Mitome M, Hasegawa T, Shirakawa T. Mastication influences the survival of newly generated cells in mouse dentate gyrus. Neuroreport 2005; 16:249-52. [PMID: 15706229 DOI: 10.1097/00001756-200502280-00009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We examined the effects of soft food and tooth loss on neurogenesis in the adult dentate gyrus. Four-week-old mice were subjected to a powder diet for 10 weeks with or without removal of molars. They received a daily injection of bromodeoxyuridine (BrdU) at 14 weeks of age for 12 consecutive days. The number of BrdU-positive cells in the dentate gyrus of these mice did not differ from that of control at 1 day after the last BrdU injection. However, the BrdU-positive cells in these mice showed a larger reduction in number than in control at 5 weeks after the BrdU injection and the ratio of neurons to BrdU-positive cells decreased in the molarless mice. These results suggest that mastication influences the survival of newly generated cells in the adult dentate gyrus.
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Affiliation(s)
- Masato Mitome
- Oral Functional Science, Hokkaido University Graduate School of Dental Medicine, N13W7 Kita-ku, Sapporo 060-8586, Japan.
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