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Raymond J, Morin A, Bradley-Garcia M, Plamondon H. Juvenile/Peripubertal Exposure to Omega-3 and Environmental Enrichment Differentially Affects CORT Secretion and Adulthood Stress Coping, Sociability, and CA3 Glucocorticoid Receptor Expression in Male and Female Rats. Nutrients 2024; 16:2350. [PMID: 39064793 PMCID: PMC11279577 DOI: 10.3390/nu16142350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 07/11/2024] [Accepted: 07/16/2024] [Indexed: 07/28/2024] Open
Abstract
In adult rats, omega-3 supplementation through fish oil (FO) and environmental enrichment (EE) have shown beneficial effects on cognition and stress regulation. This study assessed sex-specific effects of FO and EE during adolescence, a period critical for brain maturation, on adulthood coping mechanisms, sociability, and glucocorticoid regulation. An amount of 64 Wistar rats [n = 32/sex; postnatal day (PND) 23] were assigned to supplementation of control soybean oil (CSO) or menhaden fish oil (FO; 0.3 mL/100 g) from PND28 to 47 and exposed to EE or regular cage (RC) housing from PND28 to 58, with their blood corticosterone (CORT) levels being assessed weekly. As adults, exposure to repeated forced swim tests (FSTs; PND90-91) enabled analysis of coping responses, while socioemotional and memory responses were evaluated using the OFT, EPM, SIT, and Y maze tests (PND92-94). Immunohistochemistry determined hippocampal CA1/CA3 glucocorticoid receptor (GR) expression (PND95). CORT secretion gradually increased as the supplementation period elapsed in female rats, while changes were minimal in males. Coping strategies in the FST differed between sexes, particularly in FO-fed rats, where females and males, respectively, favoured floating and tail support to minimise energy consumption and maintain immobility. In the SIT, FO/EE promoted sociability in females, while a CSO diet favoured social recognition in males. Reduced CA3 GR-ir expression was found in FO/RC and CSO/EE rat groups, supporting stress resilience and memory consolidation. Our findings support environment and dietary conditions to exert a sex-specific impact on biobehavioural responses.
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Affiliation(s)
| | | | | | - Hélène Plamondon
- Behavioural Neuroscience Group, School of Psychology, University of Ottawa, 136 Jean-Jacques Lussier, Ottawa, ON K1N 6N5, Canada; (J.R.); (A.M.); (M.B.-G.)
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Sekundo C, Frese C, Alich N, Langowski E, Awounvo S, Wolff D, Zenthöfer A. Very old age impacts masticatory performance: a study among sexagenarians to centenarians. Clin Oral Investig 2024; 28:349. [PMID: 38822870 PMCID: PMC11144126 DOI: 10.1007/s00784-024-05742-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 05/24/2024] [Indexed: 06/03/2024]
Abstract
OBJECTIVE This cross-sectional pilot study evaluated the impact of age on masticatory performance among individuals aged 65 to 106 years, as part of the Heidelberg Dental Centenarian Study (HD-100Z) conducted in South-Western Germany. MATERIALS AND METHODS A total of 31 centenarians were recruited, alongside 31 individuals each from the age groups 75-99 and 65-74, matched based on sex, prosthetic status, and number of teeth. Masticatory performance was assessed using a two-colored chewing gum test and digital image processing. Multiple linear regression analysis was performed to assess the effect of age, sex, number of teeth, type of prosthesis on the masticatory performance. RESULTS Masticatory performance, as measured by the standard deviation of hue in the chewing gum test, decreased significantly in centenarians compared to individuals aged 75-99 years (-0.112, p = 0.037) and those aged 65-74 years (-0.274, p < 0.001). The effects of sex, number of teeth, and type of prosthesis on masticatory performance were not significant associations (p ≥ 0.135). CONCLUSION The findings suggest that age may have a significant influence on masticatory performance in the studied age groups, challenging previous notions that aging itself has little impact on masticatory ability. The inclusion of centenarians in the study highlights the need for further investigation into masticatory function in age groups reaching up to 100 years or more. CLINICAL RELEVANCE This study contributes to the understanding of how ageing affects oral function, which may guide dental treatment approaches for older individuals, and set the stage for more in-depth investigations in this field in the future.
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Affiliation(s)
- Caroline Sekundo
- Heidelberg University, Department of Conservative Dentistry, University Hospital Heidelberg, Heidelberg, Germany.
| | - Cornelia Frese
- Heidelberg University, Department of Conservative Dentistry, University Hospital Heidelberg, Heidelberg, Germany
| | - Niklas Alich
- Heidelberg University, Department of Conservative Dentistry, University Hospital Heidelberg, Heidelberg, Germany
| | - Eva Langowski
- Heidelberg University, Department of Conservative Dentistry, University Hospital Heidelberg, Heidelberg, Germany
| | - Sinclair Awounvo
- Institute of Medical Biometry, Heidelberg University, Heidelberg, Germany
| | - Diana Wolff
- Heidelberg University, Department of Conservative Dentistry, University Hospital Heidelberg, Heidelberg, Germany
| | - Andreas Zenthöfer
- Heidelberg University, Department of Prosthodontics, University Hospital Heidelberg, Heidelberg, Germany
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Nakamura H, Noguchi-Shinohara M, Ishimiya-Jokaji M, Kobayashi Y, Isa M, Ide K, Kawano T, Kawashiri S, Uchida K, Tatewaki Y, Taki Y, Ohara T, Ninomiya T, Ono K. Brain atrophy in normal older adult links tooth loss and diet changes to future cognitive decline. NPJ AGING 2024; 10:20. [PMID: 38519528 PMCID: PMC10960014 DOI: 10.1038/s41514-024-00146-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Accepted: 03/05/2024] [Indexed: 03/25/2024]
Abstract
Several studies have found associations between poor oral health, particularly tooth loss and cognitive decline. However, the specific brain regions affected by tooth loss and the probable causes remain unclear. We conducted a population-based longitudinal cohort study in Nakajima, Nanao City, Japan. Between 2016 and 2018, 2454 residents aged ≥60 participated, covering 92.9% of the local age demographics. This study used comprehensive approach by combining detailed dental examinations, dietary assessments, magnetic resonance imaging (MRI) analysis, and cognitive evaluations. Tooth loss, even in cognitively normal individuals, is associated with parahippocampal gyrus atrophy and increased WMH volume, both of which are characteristics of dementia. Tooth loss was associated with altered dietary patterns, notably a reduction in plant-based food intake and an increase in fatty, processed food intake. This study highlights a possible preventative pathway where oral health may play a significant role in preventing the early neuropathological shifts associated with dementia.
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Affiliation(s)
- Hiroyuki Nakamura
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan.
| | - Moeko Noguchi-Shinohara
- Department of Neurology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Mai Ishimiya-Jokaji
- Department of Oral and Maxillofacial Surgery, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Yutaka Kobayashi
- Department of Oral and Maxillofacial Surgery, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Mikana Isa
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Kentaro Ide
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Toshihiro Kawano
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Shuichi Kawashiri
- Department of Oral and Maxillofacial Surgery, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Kazuhiro Uchida
- Department of Health Promotion, School of Health and Nutrition Sciences, Nakamura-Gakuen University, Fukuoka, Japan
| | - Yasuko Tatewaki
- Department of Nuclear Medicine and Radiology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Yasuyuki Taki
- Department of Nuclear Medicine and Radiology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Tomoyuki Ohara
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshiharu Ninomiya
- Department of Epidemiology and Public Health, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kenjiro Ono
- Department of Neurology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
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Knijn FV, Verhoeff MC, Bindels KL, Fuh JL, Lin CS, Su N, Lobbezoo F. Are demographic factors, masticatory performance and structural brain signatures associated with cognitive impairment in older people? A pilot study of cross-sectional neuroimaging data. J Oral Rehabil 2024; 51:321-327. [PMID: 37727024 DOI: 10.1111/joor.13591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 08/04/2023] [Accepted: 08/17/2023] [Indexed: 09/21/2023]
Abstract
BACKGROUND The occurrence of cognitive impairment (CI) is expected to increase within an ageing population. CI is associated with tooth loss, which influences masticatory performance. A decrease in masticatory performance may cause functional and morphological changes in the brain. However, whether CI is associated with masticatory performance, demographics, and structural brain signatures has not been studied yet. OBJECTIVES To assess the associations between CI on the one hand, and masticatory performance, demographic factors, and structural brain signatures (i.e. cortical volume and thickness) on the other hand. METHODS In total, 18 older adults with CI (mean ± SD age = 72.2 ± 9.5 years) and 68 older adults without CI (65.7 ± 7.5 years) were included in this study. Masticatory performance was quantified using a colour-changeable chewing gum. A Magnetic Resonance Imaging (MRI) scan was used to map structural brain signatures. To study our aim, a multivariate binary logistic regression analysis with backward selection was performed. RESULTS The cortical volume of the right entorhinal cortex was negatively associated with CI (p < .01). However, demographic factors, masticatory performance, and the other structural brain signatures under investigation were not associated with CI. CONCLUSION A decrease in the volume of the right entorhinal cortex is associated with CI in older people.
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Affiliation(s)
- Fleur V Knijn
- Department of Orofacial pain and Dysfunction, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Merel C Verhoeff
- Department of Orofacial pain and Dysfunction, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Karlijn L Bindels
- Department of Orofacial pain and Dysfunction, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Jong-Ling Fuh
- Division of General Neurology, Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chia-Shu Lin
- Department of Dentistry, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Naichuan Su
- Department of Oral Public Health, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Frank Lobbezoo
- Department of Orofacial pain and Dysfunction, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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Akitomo T, Kusaka S, Usuda M, Kametani M, Kaneki A, Nishimura T, Ogawa M, Mitsuhata C, Nomura R. Fusion of a Tooth with a Supernumerary Tooth: A Case Report and Literature Review of 35 Cases. CHILDREN (BASEL, SWITZERLAND) 2023; 11:6. [PMID: 38275427 PMCID: PMC10814903 DOI: 10.3390/children11010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 12/12/2023] [Accepted: 12/17/2023] [Indexed: 01/27/2024]
Abstract
Tooth fusion is a dental anomaly with a prevalence of 0.1% in permanent dentition. The aim of this paper is to present the occurrence, region of fusion, and prognosis of fused tooth which is a very rare case in the literature. The authors present a very rare case with a maxillary right lateral incisor fused to a supernumerary tooth on the palatal side. The eruption was delayed, but eruption occurred naturally at 9 years and 6 months. However, cone-beam computed tomography at 11 years and 6 months revealed it was diagnosed as a fused tooth. The authors undertook a literature review over the past 10 years and found 30 articles about fused teeth between permanent teeth and supernumerary teeth. It was more common in males than females and there were no differences depending on the occurrence. Mesiodistal fusion was more common in the incisor region, while labiopalatal fusion was more common in the molar region. Most cases required dental treatment with a surgical approach, root canal treatment, or orthodontic treatment. The present study highlights the importance of long-term follow-up and suggests the region of fusion and prognosis of the fused tooth may vary depending on the occurrence.
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Affiliation(s)
- Tatsuya Akitomo
- Department of Pediatric Dentistry, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan; (S.K.); (M.U.); (M.K.); (A.K.); (T.N.); (M.O.); (C.M.); (R.N.)
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6
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Oue H, Hatakeyama R, Ishida E, Yokoi M, Tsuga K. Experimental tooth loss affects spatial learning function and blood-brain barrier of mice. Oral Dis 2023; 29:2907-2916. [PMID: 36114741 DOI: 10.1111/odi.14379] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/28/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVE This study aims to investigate how experimental tooth loss affected learning, memory function, and brain pathophysiology in mice. MATERIALS AND METHODS The mice (C57BL/6 J, 2-month-old, male) were divided into tooth loss and control groups. The behavioral test battery was performed at 6 and 12 months after tooth extraction. The protein levels of the tight junctions in the brains of the mice were analyzed. Hippocampal astrocyte was measured using immunohistochemical staining. RESULTS The results of behavioral tests and biochemical analysis performed during the 6 months observation period did not show significant differences between the groups. However, the escape latency in the tooth loss group was significantly longer than that in the control group at the 12 months after tooth extraction. The level of claudin-5 decreased in the tooth loss group. Additionally, hippocampal astrogliosis was found in the tooth loss group. CONCLUSIONS Experimental tooth loss reduced the level of claudin-5 and caused astrogliosis in the brains of mice, which was accompanied by deterioration of learning functions. This study may provide a new insight about the association between tooth loss and cognitive dysfunction.
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Affiliation(s)
- Hiroshi Oue
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Rie Hatakeyama
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Eri Ishida
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Miyuki Yokoi
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kazuhiro Tsuga
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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Sun W, Okihara H, Ogawa T, Ishidori H, Misawa E, Kato C, Ono T. Pre-Adolescent Diet Normalization Restores Cognitive Function in Young Mice. J Clin Med 2023; 12:jcm12113642. [PMID: 37297836 DOI: 10.3390/jcm12113642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/15/2023] [Accepted: 05/18/2023] [Indexed: 06/12/2023] Open
Abstract
Mastication is a fundamental function critical for human health. Controlled by the central nervous system (CNS), it influences CNS development and function. A poor masticatory performance causes cognitive dysfunction in both older adults and children. Improving mastication may prevent cognitive decline. However, no study has determined the period of masticatory dysfunction that impairs children's later acquisition of cognitive function. Herein, we developed an animal model wherein a soft diet was switched to a normal diet at early and late time points in young mice. We aimed to investigate the impact of restored mastication on learning and memory function. Behavioral studies were conducted to evaluate learning and memory. Micro-CT was used to evaluate orofacial structural differences, while histological and biochemical approaches were employed to assess differences in the hippocampal morphology and function. Correction to a hard-textured diet before adolescence restored mastication and cognitive function through the stimulation of neurogenesis, extracellular signal-regulated kinases, the cyclic adenosine monophosphate-response element-binding protein pathway, and the brain-derived neurotrophic factor, tyrosine receptor B. In contrast, post-adolescent diet normalization failed to rescue full mastication and led to impaired cognitive function, neuronal loss, and decreased hippocampal neurogenesis. These findings revealed a functional linkage between the masticatory and cognitive function in mice during the juvenile to adolescent period, highlighting the need for adequate food texture and early intervention for mastication-related cognitive impairment in children.
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Affiliation(s)
- Wenqian Sun
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 1138510, Japan
| | - Hidemasa Okihara
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 1138510, Japan
| | - Takuya Ogawa
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 1138510, Japan
| | - Hideyuki Ishidori
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 1138510, Japan
- Department of Oral and Maxillofacial Surgery/Orthodontics, Yokohama City University Medical Center, 4-57 Urafune-cho, Minami-ku, Yokohama 2320024, Japan
| | - Eri Misawa
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 1138510, Japan
| | - Chiho Kato
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 1138510, Japan
| | - Takashi Ono
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 1138510, Japan
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Zhang JH, Tasaki T, Tsukamoto M, Wang KY, Kubo KY, Azuma K. Deletion of Wnt10a Is Implicated in Hippocampal Neurodegeneration in Mice. Biomedicines 2022; 10:biomedicines10071500. [PMID: 35884806 PMCID: PMC9313158 DOI: 10.3390/biomedicines10071500] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 11/16/2022] Open
Abstract
The hippocampus plays an important role in maintaining normal cognitive function and is closely associated with the neuropathogenesis of dementia. Wnt signaling is relevant to neuronal development and maturation, synaptic formation, and plasticity. The role of Wnt10a in hippocampus-associated cognition, however, is largely unclear. Here, we examined the morphological and functional alterations in the hippocampus of Wnt10a-knockout (Wnt10a-/-) mice. Neurobehavioral tests revealed that Wnt10a-/- mice exhibited spatial memory impairment and anxiety-like behavior. Immunostaining and Western blot findings showed that the protein expressions of β-catenin, brain-derived neurotrophic factor, and doublecortin were significantly decreased and that the number of activated microglia increased, accompanied by amyloid-β accumulation, synaptic dysfunction, and microglia-associated neuroinflammation in the hippocampi of Wnt10a-/- mice. Our findings revealed that the deletion of Wnt10a decreased neurogenesis, impaired synaptic function, and induced hippocampal neuroinflammation, eventually leading to hippocampal neurodegeneration and memory deficit, possibly through the β-catenin signaling pathway, providing a novel insight into preventive approaches for hippocampus-dependent cognitive impairment.
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Affiliation(s)
- Jia-He Zhang
- Department of Anatomy, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyusyu 807-8555, Fukuoka, Japan;
| | - Takashi Tasaki
- Department of Pathology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Kanagawa, Japan;
| | - Manabu Tsukamoto
- Department of Orthopedic Surgery, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyusyu 807-8555, Fukuoka, Japan;
| | - Ke-Yong Wang
- Shared-Use Research Center, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyusyu 807-8555, Fukuoka, Japan;
| | - Kin-ya Kubo
- Faculty of Human Life and Environmental Science, Nagoya Women’s University, 3-40 Shioji-cho, Mizuho-ku, Nagoya 467-8610, Aichi, Japan;
| | - Kagaku Azuma
- Department of Anatomy, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyusyu 807-8555, Fukuoka, Japan;
- Correspondence: ; Tel.: +81-93-691-7418; Fax: +81-93-691-8544
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de Siqueira Mendes FDCC, de Almeida MNF, Falsoni M, Andrade MLF, Felício APG, da Paixão LTVB, Júnior FLDA, Anthony DC, Brites D, Diniz CWP, Sosthenes MCK. The Sedentary Lifestyle and Masticatory Dysfunction: Time to Review the Contribution to Age-Associated Cognitive Decline and Astrocyte Morphotypes in the Dentate Gyrus. Int J Mol Sci 2022; 23:ijms23116342. [PMID: 35683023 PMCID: PMC9180988 DOI: 10.3390/ijms23116342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/15/2022] [Accepted: 05/16/2022] [Indexed: 02/01/2023] Open
Abstract
As aging and cognitive decline progresses, the impact of a sedentary lifestyle on the appearance of environment-dependent cellular morphologies in the brain becomes more apparent. Sedentary living is also associated with poor oral health, which is known to correlate with the rate of cognitive decline. Here, we will review the evidence for the interplay between mastication and environmental enrichment and assess the impact of each on the structure of the brain. In previous studies, we explored the relationship between behavior and the morphological features of dentate gyrus glial fibrillary acidic protein (GFAP)-positive astrocytes during aging in contrasting environments and in the context of induced masticatory dysfunction. Hierarchical cluster and discriminant analysis of GFAP-positive astrocytes from the dentate gyrus molecular layer revealed that the proportion of AST1 (astrocyte arbors with greater complexity phenotype) and AST2 (lower complexity) are differentially affected by environment, aging and masticatory dysfunction, but the relationship is not straightforward. Here we re-evaluated our previous reconstructions by comparing dorsal and ventral astrocyte morphologies in the dentate gyrus, and we found that morphological complexity was the variable that contributed most to cluster formation across the experimental groups. In general, reducing masticatory activity increases astrocyte morphological complexity, and the effect is most marked in the ventral dentate gyrus, whereas the effect of environment was more marked in the dorsal dentate gyrus. All morphotypes retained their basic structural organization in intact tissue, suggesting that they are subtypes with a non-proliferative astrocyte profile. In summary, the increased complexity of astrocytes in situations where neuronal loss and behavioral deficits are present is counterintuitive, but highlights the need to better understand the role of the astrocyte in these conditions.
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Affiliation(s)
- Fabíola de Carvalho Chaves de Siqueira Mendes
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
- Curso de Medicina, Centro Universitário do Estado do Pará, Belém 66613-903, PA, Brazil
| | - Marina Negrão Frota de Almeida
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - Manoela Falsoni
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - Marcia Lorena Ferreira Andrade
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - André Pinheiro Gurgel Felício
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - Luisa Taynah Vasconcelos Barbosa da Paixão
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - Fábio Leite do Amaral Júnior
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - Daniel Clive Anthony
- Laboratory of Experimental Neuropathology, Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK;
| | - Dora Brites
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-004 Lisbon, Portugal;
- Department of Pharmaceutical Sciences and Medicines, Faculty of Pharmacy, Universidade de Lisboa, 1649-004 Lisbon, Portugal
| | - Cristovam Wanderley Picanço Diniz
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
| | - Marcia Consentino Kronka Sosthenes
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém 66073-005, PA, Brazil; (F.d.C.C.d.S.M.); (M.N.F.d.A.); (M.F.); (M.L.F.A.); (A.P.G.F.); (L.T.V.B.d.P.); (F.L.d.A.J.); (C.W.P.D.)
- Correspondence:
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10
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Jockusch J, Hopfenmüller W, Nitschke I. Chewing function and related parameters as a function of the degree of dementia: Is there a link between the brain and the mouth? J Oral Rehabil 2021; 48:1160-1172. [PMID: 34288029 PMCID: PMC9291087 DOI: 10.1111/joor.13231] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 06/23/2021] [Accepted: 07/06/2021] [Indexed: 02/06/2023]
Abstract
Background To date, no study has investigated the association between chewing function and related parameters as a function of the degree of dementia using a finer subdivision of the values of the Mini‐Mental State Examination (MMSE). Objective This study aimed to investigate the differences in chewing function and related parameters as a function of the degree of dementia. Methods An analysis of cross‐sectional data obtained from the OrBiD (Oral Health, Bite Force, and Dementia) pilot study was performed. The participants were stratified into five groups based on the outcomes of the MMSE (no dementia, MMSE 28–30; mild cognitive impairment, MMSE 25–27; mild dementia, MMSE 18–24; moderate dementia, MMSE 10–17; severe dementia, MMSE <10). The chewing efficiency, maximum occlusal force and related parameters (number of supporting zones, number of teeth, Eichner index, tooth/denture status, denture quality, and dental treatment needs) were recorded. Results The MMSE groups showed significantly different chewing efficiencies (p = .003, Jonckheere‐Terpstra test) and maximum occlusal forces (p = .003, Jonckheere‐Terpstra test), but the number of supporting zones (p = .055, chi‐square test) and the number of natural teeth (p = .126, chi‐square test) were not different. The Eichner index, tooth/denture status, denture quality and dental treatment need showed no significant associations with the degree of dementia. Conclusion An improvement in the usability of the measurement methods for assessing chewing function in people with dementia is needed. Research involving people with dementia is necessary because the nutritional situation often deteriorates rapidly within a multifactorial system, which includes chewing ability and oral health.
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Affiliation(s)
- Julia Jockusch
- University Research Priority Program "Dynamics of Healthy Aging", University of Zurich, Zurich, Switzerland
| | - Werner Hopfenmüller
- Institute of Biometry and Clinical Epidemiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Ina Nitschke
- Clinic of General, Special Care and Geriatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.,Department of Prosthodontics and Materials Science, Gerodontology Section, University of Leipzig, Leipzig, Germany
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11
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Abstract
The global population of 80 years and older is predicted to reach 437
million by 2050. As overall brain structure and function progressively degrades,
older and younger adults show differences in sensorimotor performance and brain
activity in the sensorimotor regions. Oral sensorimotor functions are an
important area of focus in natural aging and Alzheimer’s Disease (AD)
because oral health issues are commonly found in both elderly and AD
populations. While human behavioral studies on changes in oral sensorimotor
functions abound, very little is known about their neuronal correlates in normal
and pathological aging.
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12
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de Siqueira Mendes FDCC, Paixão LTVB, Diniz DG, Anthony DC, Brites D, Diniz CWP, Sosthenes MCK. Sedentary Life and Reduced Mastication Impair Spatial Learning and Memory and Differentially Affect Dentate Gyrus Astrocyte Subtypes in the Aged Mice. Front Neurosci 2021; 15:632216. [PMID: 33935629 PMCID: PMC8081835 DOI: 10.3389/fnins.2021.632216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 03/03/2021] [Indexed: 11/13/2022] Open
Abstract
To explore the impact of reduced mastication and a sedentary lifestyle on spatial learning and memory in the aged mice, as well as on the morphology of astrocytes in the molecular layer of dentate gyrus (MolDG), different masticatory regimens were imposed. Control mice received a pellet-type hard diet, while the reduced masticatory activity group received a pellet diet followed by a powdered diet, and the masticatory rehabilitation group received a pellet diet, followed by powder diet and then a pellet again. To mimic sedentary or active lifestyles, mice were housed in an impoverished environment of standard cages or in an enriched environment. The Morris Water Maze (MWM) test showed that masticatory-deprived group, regardless of environment, was not able to learn and remember the hidden platform location, but masticatory rehabilitation combined with enriched environment recovered such disabilities. Microscopic three-dimensional reconstructions of 1,800 glial fibrillary acidic protein (GFAP)-immunolabeled astrocytes from the external third of the MolDG were generated using a stereological systematic and random sampling approach. Hierarchical cluster analysis allowed the characterization into two main groups of astrocytes with greater and lower morphological complexities, respectively, AST1 and AST2. When compared to compared to the hard diet group subjected to impoverished environment, deprived animals maintained in the same environment for 6 months showed remarkable shrinkage of astrocyte branches. However, the long-term environmental enrichment (18-month-old) applied to the deprived group reversed the shrinkage effect, with significant increase in the morphological complexity of AST1 and AST2, when in an impoverished or enriched environment. During housing under enriched environment, complexity of branches of AST1 and AST2 was reduced by the powder diet (pellet followed by powder regimes) in young but not in old mice, where it was reversed by pellet diet (pellet followed by powder and pellet regime again). The same was not true for mice housed under impoverished environment. Interestingly, we were unable to find any correlation between MWM data and astrocyte morphological changes. Our findings indicate that both young and aged mice subjected to environmental enrichment, and under normal or rehabilitated masticatory activity, preserve spatial learning and memory. Nonetheless, data suggest that an impoverished environment and reduced mastication synergize to aggravate age-related cognitive decline; however, the association with morphological diversity of AST1 and AST2 at the MolDG requires further investigation.
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Affiliation(s)
- Fabíola de Carvalho Chaves de Siqueira Mendes
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém, Brazil.,Curso de Medicina, Centro Universitário do Estado do Pará, Belém, Brazil
| | - Luisa Taynah Vasconcelos Barbosa Paixão
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém, Brazil
| | - Daniel Guerreiro Diniz
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém, Brazil.,Laboratório de Microscopia Eletrônica, Instituto Evandro Chagas, Belém, Brazil
| | - Daniel Clive Anthony
- Laboratory of Experimental Neuropathology, Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Dora Brites
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal.,Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Cristovam Wanderley Picanço Diniz
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém, Brazil
| | - Marcia Consentino Kronka Sosthenes
- Laboratório de Investigações em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém, Brazil
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13
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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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14
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Kubo KY, Ogasawara A, Tsugane H, Iinuma M, Takahashi T, Azuma K. Environmental enrichment improves hypomyelination, synaptic alterations, and memory deficits caused by tooth loss in aged SAMP8 mice. Arch Oral Biol 2021; 123:105039. [PMID: 33454419 DOI: 10.1016/j.archoralbio.2021.105039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/01/2020] [Accepted: 12/29/2020] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Prolonged mild stress due to tooth loss leads to morphologic and functional alterations of the hippocampus, as well as cognitive memory impairments in aged animals. An enriched environment improves stress-induced hippocampus-dependent cognitive impairments. The potential mechanisms underlying the beneficial effects of an enriched environment, however, remain unclear. In the present study, we investigated whether an enriched environment affects morphologic remodeling of the hippocampal myelin, synapses, and spatial learning deficits caused by tooth loss in aged senescence-accelerated mouse strain P8 (SAMP8) mice. DESIGN SAMP8 mice (8 months old) with either teeth intact or teeth extracted were raised in a standard or enriched environment for three weeks. Spatial learning and memory ability was evaluated in a Morris water maze test. The morphologic features of the myelin sheath and synapses in the hippocampus were investigated by electron microscopy. RESULTS Mice with tooth loss had a thinner myelin sheaths and shorter postsynaptic densities in the hippocampal CA1 region, and impaired hippocampus-dependent spatial learning ability. Exposure to an enriched environment ameliorated the hypomyelination and synaptic alterations, and spatial learning and memory impairments induced by tooth loss in aged SAMP8 mice. CONCLUSION Our findings indicate that an enriched environment ameliorates hippocampal hypomyelination and synapse morphologic abnormalities, as well as learning deficits induced by tooth loss in aged SAMP8 mice.
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Affiliation(s)
- Kin-Ya Kubo
- Graduate School of Human Life Science, Nagoya Women's University, 3-40 Shioji-cho, Mizuho-ku, Nagoya, Aichi, 467-8610, Japan.
| | - Akifumi Ogasawara
- Departments of Pediatric Dentistry, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan
| | - Hiroko Tsugane
- Departments of Pediatric Dentistry, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan
| | - Mitsuo Iinuma
- Departments of Pediatric Dentistry, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan
| | - Toru Takahashi
- 10 Sue-machi, Kanazawa City, Ishikawa Prefecture, 920-1392, Faculty of Nutrition, Department of Nutrition, Kanazawa Gakuin University, Japan
| | - Kagaku Azuma
- Department of Anatomy, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyusyu, 807-8555, Japan
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15
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Egashira R, Umezaki Y, Mizutani S, Obata T, Yamaguchi M, Tamai K, Yoshida M, Makino M, Naito T. Relationship between cerebral atrophy and number of present teeth in elderly individuals with cognitive decline. Exp Gerontol 2020; 144:111189. [PMID: 33285222 DOI: 10.1016/j.exger.2020.111189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 11/30/2020] [Accepted: 12/02/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND AIM Recent shifts in the distribution of Japan's population towards older ages, have meant that the chance of encountering patients with dementia in dental clinics is increasing. Many studies have shown that the brain volume decreases along with the progression of dementia. Although previous studies have reported a relationship between tooth loss or periodontitis and the onset of dementia, the pathological mechanisms underlying this association have not been elucidated. In this study, we aimed to examine the relationship between the oral condition and brain atrophy and to discuss how to adequately deal with patients with dementia. PARTICIPANTS AND METHODS This cross-sectional study included 15 participants who underwent brain magnetic resonance imaging (MRI). The participants were 60 years or older and presented with cognitive decline, including Alzheimer's disease (AD) and mild cognitive impairment (MCI), diagnosed by a neurologist. We obtained information on the oral condition, lifestyle, cognitive function, and brain atrophy. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). MR images of each patient were analyzed using the voxel-based specific regional analysis system for Alzheimer's disease (VSRAD) to provide a quantitative measure of the degree of brain atrophy. RESULTS The study population included 4 male and 11 female patients. The mean age and mean number of present teeth were 75.9 years (SD 6.7) and 15.0 (SD 11.1), respectively. The median MMSE score was 25.6 (SD 3.7). The degree of atrophy of the whole brain was significantly correlated with the number of present teeth (ρ = -0.72, p < 0.05) and the presence of a daily exercise habit (ρ = -0.66, p < 0.05). CONCLUSION This study demonstrated that the number of present teeth could be an indicator of the progress of dementia. Preserving the teeth as well as the acquisition of a regular exercise habit might be important for preventing progression of dementia. Further research examining a larger study population and analyzing a greater number of factors is warranted.
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Affiliation(s)
- Rui Egashira
- Section of Geriatric Dentistry, Department of General Dentistry, Fukuoka Dental College, Fukuoka, Japan
| | - Yojiro Umezaki
- Section of Geriatric Dentistry, Department of General Dentistry, Fukuoka Dental College, Fukuoka, Japan.
| | - Shinsuke Mizutani
- Section of Geriatric Dentistry and Perioperative Medicine in Dentistry, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyusyu University, Fukuoka, Japan; OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | | | - Masahiro Yamaguchi
- Section of Geriatric Dentistry, Department of General Dentistry, Fukuoka Dental College, Fukuoka, Japan
| | - Keiko Tamai
- Section of Geriatric Dentistry, Department of General Dentistry, Fukuoka Dental College, Fukuoka, Japan
| | - Mizuki Yoshida
- Section of Geriatric Dentistry, Department of General Dentistry, Fukuoka Dental College, Fukuoka, Japan
| | - Michiko Makino
- The Center for Visiting Dental Service, Fukuoka Dental College, Fukuoka, Japan
| | - Toru Naito
- Section of Geriatric Dentistry, Department of General Dentistry, Fukuoka Dental College, Fukuoka, Japan
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16
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Lopez-Chaichio L, Padial-Molina M, O'Valle F, Gil-Montoya JA, Catena A, Galindo-Moreno P. Oral health and healthy chewing for healthy cognitive ageing: A comprehensive narrative review. Gerodontology 2020; 38:126-135. [PMID: 33179281 DOI: 10.1111/ger.12510] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 09/11/2020] [Accepted: 10/24/2020] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Ageing leads to physiological cognitive decline that it is worsened in people with neurodegenerative diseases such as Alzheimer's disease. Despite the ongoing search for a solution to this cognitive decline, no effective remedies have been established. It has been determined that modifiable external factors, such as oral health and occlusal function, prevent cognitive decline. OBJECTIVE To analyse the primary interactions between occlusal function and cognitive functions. MAIN FINDINGS Masticatory function is related to cognitive functions. In particular, current evidence, from both animal and human studies, suggests that the activation of masticatory muscles and proper mastication, with natural teeth or dental prosthesis, induces the release of several mediators and the activation of specific brain areas. Together, they result in higher neuronal activity, neurotrophic support, blood flow and the prevention of amyloid-beta plaque formation. Thus, all the components of the masticatory system must work together in order to preserve cognitive function. CONCLUSIONS Available evidence suggests that oral and cognitive health are more interconnected than previously thought. Therefore, maintenance and adequate restoration of the whole masticatory system are important for the prevention of cognitive decline. In summary, oral and chewing health lead to healthy cognitive ageing.
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Affiliation(s)
- Lucia Lopez-Chaichio
- Department of Oral Surgery and Implant Dentistry, School of Dentistry, University of Granada, Granada, Spain
| | - Miguel Padial-Molina
- Department of Oral Surgery and Implant Dentistry, School of Dentistry, University of Granada, Granada, Spain
| | - Francisco O'Valle
- Department of Pathology and IBIMER, School of Medicine, University of Granada, Granada, Spain.,Biosanitary Institute of Granada (ibs.Granada), University of Granada, Granada, Spain
| | - Jose Antonio Gil-Montoya
- Biosanitary Institute of Granada (ibs.Granada), University of Granada, Granada, Spain.,Department of Gerodontology, School of Dentistry, University of Granada, Granada, Spain
| | - Andres Catena
- Mind, Brain and Behavior Research Center, University of Granada, Granada, Spain
| | - Pablo Galindo-Moreno
- Department of Oral Surgery and Implant Dentistry, School of Dentistry, University of Granada, Granada, Spain
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17
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Liu YCG, Lan SJ, Hirano H, Lin LM, Hori K, Lin CS, Zwetchkenbaum S, Minakuchi S, Teng AYT. Update and review of the gerodontology prospective for 2020's: Linking the interactions of oral (hypo)-functions to health vs. systemic diseases. J Dent Sci 2020; 16:757-773. [PMID: 33854730 PMCID: PMC8025188 DOI: 10.1016/j.jds.2020.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/03/2020] [Indexed: 02/07/2023] Open
Abstract
New lines of evidence suggest that the oral-systemic medical links and oral hypo-function are progressively transcending beyond the traditional clinical signs and symptoms of oral diseases. Research into the dysbiotic microbiome, host immune/inflammatory regulations and patho-physiologic changes and subsequent adaptations through the oral-systemic measures under ageism points to pathways leading to mastication deficiency, dysphagia, signature brain activities for (neuro)-cognition circuitries, dementia and certain cancers of the digestive system as well. Therefore, the coming era of oral health-linked systemic disorders will likely reshape the future of diagnostics in oral geriatrics, treatment modalities and professional therapies in clinical disciplines. In parallel to these highlights, a recent international symposium was jointly held by the International Association of Gerontology and Geriatrics (IAGG), Japanese Society of Gerodontology (JSG), the representative of USA and Taiwan Academy of Geriatric Dentistry (TAGD) on Oct 25th, 2019. Herein, specific notes are briefly addressed and updated for a summative prospective from this symposium and the recent literature.
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Affiliation(s)
- Yen Chun G. Liu
- Center for Osteoimmunology & Biotechnology Research (COBR) and Dept. of Oral Hygiene, College of Dental Medicine, Kaohsiung Medical University (KMU), Kaohsiung, Taiwan
- Corresponding author. Dept. of Oral Hygiene & COBR, College of Dental Medicine, Kaohsiung Medical University; No. 100, Shih-Chun 1st Rd, Kaohsiung 807, Taiwan. Fax: +886 07 3223141.
| | - Shou-Jen Lan
- Dept. of Healthcare Administration, Asia University, Tai-Chung, Taiwan
| | - Hirohiko Hirano
- Research Team for Promoting Independence & Mental Health, and Dentistry & Oral Surgery, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan
| | - Li-min Lin
- Div. of Oral Pathology & Oral Maxillo-facial Radiology, School of Dentistry, Kaohsiung Medical University & KMU-Hospital, Kaohsiung, Taiwan
| | - Kazuhiro Hori
- Div. of Comprehensive Prosthodontics, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Chia-shu Lin
- Dept. of Dentistry, School of Dentistry, National Yang-Ming University, Taipei, Taiwan
| | - Samuel Zwetchkenbaum
- Rhode Island Dept. of Health, Rhode Island, USA
- School of Public Health, Brown University, Providence, RI, USA
| | - Shunsuke Minakuchi
- Gerodontology & Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Andy Yen-Tung Teng
- Center for Osteoimmunology & Biotechnology Research (COBR) and Dept. of Oral Hygiene, College of Dental Medicine, Kaohsiung Medical University (KMU), Kaohsiung, Taiwan
- Center for Osteoimmunology & Biotechnology Research (COBR) and School of Dentistry, College of Dental Medicine, Kaohsiung Medical University and KMU-Hospital, Kaohsiung, Taiwan
- Corresponding author. Center for Osteoimmunology and Biotechnology Research (COBR), College of Dental Medicine, Kaohsiung Medical University (KMU) & KMU-Hospital, Kaohsiung, Taiwan.
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18
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Memory impairment of chewing-side preference mice is associated with 5-HT-BDNF signal pathway. Mol Cell Biochem 2020; 476:303-310. [PMID: 32989626 DOI: 10.1007/s11010-020-03907-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 09/07/2020] [Indexed: 01/13/2023]
Abstract
Although tooth loss is a known risk factor of cognitive function, whether and how the chewing-side preference (CSP) affects memory impairment still remains unclear. This study evaluates the behavior changes in mice after the loss of teeth on one side and explores the role of serotonin (5-HT) and brain-derived neurotrophic factor (BDNF) signal pathway within these changes. To this end, CSP mouse models with either the removal of left unilateral molars (CSP-L) or right unilateral molars (CSP-R) were established. Morris water maze test and passive avoidance test were performed to evaluate the mice's learning and memory capacity in the 4th and 8th weeks. The correlation between CSP and brain function changes was validated with changes in 5-HT and BDNF levels. CSP mice's cognitive function was found to be decreased, along with a significant decline in 5-HT1A level, especially in CSP-R mice. BDNF and TrkB levels in CSP-R mice were also significantly lowered. These findings suggest that CSP results in memory impairment, which is associated with the 5-HT-BDNF signaling pathway.
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19
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Piancino MG, Tortarolo A, Polimeni A, Bramanti E, Bramanti P. Altered mastication adversely impacts morpho-functional features of the hippocampus: A systematic review on animal studies in three different experimental conditions involving the masticatory function. PLoS One 2020; 15:e0237872. [PMID: 32817680 PMCID: PMC7446800 DOI: 10.1371/journal.pone.0237872] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 08/04/2020] [Indexed: 02/06/2023] Open
Abstract
Recent results have established that masticatory function plays a role not only in the balance of the stomatognathic system and in the central motor control, but also in the trophism of the hippocampus and in the cognitive activity. These implications have been shown in clinical studies and in animal researches as well, by means of histological, biochemical and behavioural techniques. This systematic review describes the effects of three forms of experimentally altered mastication, namely soft-diet feeding, molar extraction and bite-raising, on the trophism and function of the hippocampus in animal models. Through a systematic search of PubMed, Embase, Web of Science, Scopus, OpenGray and GrayMatters, 645 articles were identified, 33 full text articles were assessed for eligibility and 28 articles were included in the review process. The comprehensiveness of reporting was evaluated with the ARRIVE guidelines and the risk of bias with the SYRCLE RoB tool. The literature reviewed agrees that a disturbed mastication is significantly associated with a reduced number of hippocampal pyramidal neurons in Cornu Ammonis (CA)1 and CA3, downregulation of Brain Derived Neurotrophic Factor (BDNF), reduced synaptic activity, reduced neurogenesis in the Dentate Gyrus (DG), glial proliferation, and reduced performances in behavioural tests, indicating memory impairment and reduced spatial orientation. Moreover, while the bite-raised condition, characterized by occlusal instability, is known to be a source of stress, soft-diet feeding and molar extractions were not consistently associated with a stress response. More research is needed to clarify this topic. The emerging role of chewing in the preservation of hippocampal trophism, neurogenesis and synaptic activity is worthy of interest and may contribute to the study of neurodegenerative diseases in new and potentially relevant ways.
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Affiliation(s)
- Maria Grazia Piancino
- Department of Surgical Sciences, Dental School, University of Turin, Turin, Italy
- * E-mail:
| | - Alessandro Tortarolo
- Department of Surgical Sciences, Dental School, University of Turin, Turin, Italy
| | - Antonella Polimeni
- Department of Oral and Maxillo-Facial Science, Sapienza University of Rome, Rome, Italy
| | - Ennio Bramanti
- Department of Biomedical and Dental Sciences, Morphological and Functional Images, University of Messina, Messina, Italy
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20
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Abstract
PURPOSE OF REVIEW This article provides an overview of current literature focused on oral health and cognitive impairment in older adulthood, focusing in particular on whether oral inflammation, tooth loss and masticatory dysfunction might increase the risk of cognitive impairment in this age group. RECENT FINDINGS There is now general acceptance that cognitive impairment contributes to poor oral health, largely through detrimental changes in behaviours related to maintaining good oral hygiene. There is more limited evidence for the reverse causal direction, but at least some studies now suggest that inflammatory mechanisms, tooth loss and masticatory dysfunction each have the potential to contribute to cognitive decline. SUMMARY Poorer oral health significantly correlates with cognitive dysfunction, and at least some studies suggest that there may be a bi-directional causal relationship. Randomized controlled trials assessing cognitive abilities in relation to oral hygiene or oral health interventions, or provision of removable or fixed (implant-supported) dentures, are encouraged.
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Orr ME, Reveles KR, Yeh CK, Young EH, Han X. Can oral health and oral-derived biospecimens predict progression of dementia? Oral Dis 2020; 26:249-258. [PMID: 31541581 PMCID: PMC7031023 DOI: 10.1111/odi.13201] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/09/2019] [Accepted: 08/30/2019] [Indexed: 12/13/2022]
Abstract
Growing evidence indicates that oral health and brain health are interconnected. Declining cognition and dementia coincide with lack of self‐preservation, including oral hygiene. The oral microbiota plays an important role in maintaining oral health. Emerging evidence suggests a link between oral dysbiosis and cognitive decline in patients with Alzheimer's disease. This review showcases the recent advances connecting oral health and cognitive function during aging and the potential utility of oral‐derived biospecimens to inform on brain health. Collectively, experimental findings indicate that the connection between oral health and cognition cannot be underestimated; moreover, oral biospecimens are abundant and readily obtainable without invasive procedures, which may help inform on cognitive health.
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Affiliation(s)
- Miranda E Orr
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio, San Antonio, Texas.,Geriatric Research, Education & Clinical Center and Research Service, South Texas Veterans Health Care System, San Antonio, Texas.,Department of Medicine, UT Health San Antonio, San Antonio, Texas.,Biggs Institute for Alzheimer's and Neurodegenerative Diseases, UT Health San Antonio, San Antonio, Texas.,Gerontology and Geriatric Medicine, Sticht Center for Healthy Aging and Alzheimer's Prevention, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Kelly R Reveles
- College of Pharmacy, The University of Texas at Austin, Austin, Texas.,Pharmacotherapy Education & Research Center, UT Health San Antonio, San Antonio, Texas
| | - Chih-Ko Yeh
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio, San Antonio, Texas.,Geriatric Research, Education & Clinical Center and Research Service, South Texas Veterans Health Care System, San Antonio, Texas.,Comprehensive Dentistry, School of Dentistry, UT Health San Antonio, San Antonio, Texas
| | - Eric H Young
- College of Pharmacy, The University of Texas at Austin, Austin, Texas.,Pharmacotherapy Education & Research Center, UT Health San Antonio, San Antonio, Texas
| | - Xianlin Han
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio, San Antonio, Texas.,Department of Medicine, UT Health San Antonio, San Antonio, Texas
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22
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Katano M, Kajimoto K, Iinuma M, Azuma K, Kubo KY. Tooth loss early in life induces hippocampal morphology remodeling in senescence-accelerated mouse prone 8 (SAMP8) mice. Int J Med Sci 2020; 17:517-524. [PMID: 32174782 PMCID: PMC7053313 DOI: 10.7150/ijms.40241] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/15/2020] [Indexed: 11/05/2022] Open
Abstract
Long-term tooth loss is associated with the suppression of hippocampal neurogenesis and impairment of hippocampus-dependent cognition with aging. The morphologic basis of the hippocampal alterations, however, remains unclear. In the present study, we investigated whether tooth loss early in life affects the hippocampal ultrastructure in senescence-accelerated mouse prone 8 (SAMP8) mice, using transmission electron microscopy. Male SAMP8 mice were randomized into control or tooth-loss groups. All maxillary molar teeth were removed at 1 month of age. Hippocampal morphologic alterations were evaluated at 9 months of age. Tooth loss early in life induced mitochondrial damage and lipofuscin accumulation in the hippocampal neurons. A thinner myelin sheath and decreased postsynaptic density length were also observed. Our results revealed that tooth loss early in life may lead to hippocampal ultrastructure remodeling and subsequent hippocampus-dependent cognitive impairment in SAMP8 mice with aging.
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Affiliation(s)
- Masahisa Katano
- Department of Pediatric Dentistry, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan
| | - Kyoko Kajimoto
- Department of Pediatric Dentistry, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan
| | - Mitsuo Iinuma
- Department of Pediatric Dentistry, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan
| | - Kagaku Azuma
- Department of Anatomy, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, Fukuoka, 807-8555, Japan
| | - Kin-Ya Kubo
- Graduate School of Human Life Science, Nagoya Women's University, 3-40 Shioji-cho, Mizuho-ku, Nagoya, Aichi, 467-8610, Japan
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23
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Systemic inflammation linking chronic periodontitis to cognitive decline. Brain Behav Immun 2019; 81:63-73. [PMID: 31279681 DOI: 10.1016/j.bbi.2019.07.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 07/03/2019] [Accepted: 07/03/2019] [Indexed: 12/25/2022] Open
Abstract
Persistent inflammation in the systemic immune system can impose detrimental effects on the central nervous system (CNS). Neuroinflammation might be a result of this to accelerate the progressive deterioration of neuronal functions during aging. In this regard, controlling inflammation through delaying and/or preventing chronic inflammatory diseases may be a potential strategy to prevent or modify the progression of Alzheimer's Disease (AD). Periodontitis is a chronic inflammatory disease of the oral cavity that is common among the elderly, especially for those who have decline in cognitive functions. While epidemiological findings support the association of chronic periodontitis and cognitive decline, whether they have causal relationship remains unclear. Nonetheless, the possibility that periodontopathogens, systemic immune cells and inflammatory cytokines could reach the CNS should not be overlooked. The impacts of periodontitis on CNS homeostasis and inflammation as a pathophysiological factor concerning the association between periodontitis and AD will be discussed in this review. Future work should elucidate the pathological pathways involved in periodontitis-induced cerebral infections and inflammation, and define the role of the latter in AD progression.
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24
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Tooth loss causes spatial cognitive impairment in rats through decreased cerebral blood flow and increased glutamate. Arch Oral Biol 2019; 102:225-230. [PMID: 31079020 DOI: 10.1016/j.archoralbio.2019.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 05/02/2019] [Accepted: 05/05/2019] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The loss of teeth not only causes damage to oral function but also is associated with cognitive impairment. Previous studies have reported that chewing can increase CBF, and CBF plays an important role in cognitive function. Whether the loss of teeth can lead to cognitive impairment by reducing CBF is unclear. This study aimed to investigate the changes in CBF, glutamate concentration, the expression of neuronal apoptosis-relatedBax/Bcl-2 and Caspase-3 mRNA and pyramidal cells in the hippocampus, as well as behavioral changes after tooth loss in rats. DESIGN Twelve weeks after the extraction of all maxillary molars in rats, their spatial learning and memory were tested by the Morris water maze, the CBF was detected by ASL-MRI and glutamate concentration was detected by HPLC; the expression of neuronal apoptosis-related Bax/Bcl-2 and Caspase-3 mRNA and the number of pyramidal cells in the CA1 region were also measured. RESULTS Rats with tooth loss exhibited spatial cognitive impairment in the Morris water maze, decreased CBF, increased glutamate levels andBax/Bcl-2 and Caspase-3 mRNA expression in the hippocampus; the number of pyramidal cells in the CA1 region were also reduced. CONCLUSIONS These findings suggest that the loss of teeth causes spatial cognitive impairment in rats and that the underlying mechanism might be associated with a decrease in CBF and an increase in the glutamate level in the hippocampus.
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25
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Tsai CY, Lee HP, Chang HM, Wu FC. Masticatory hypofunction effects induced by BTXA injection of hippocampal neurons in developing rats. Arch Oral Biol 2018; 96:122-129. [PMID: 30227358 DOI: 10.1016/j.archoralbio.2018.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/07/2018] [Accepted: 09/09/2018] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND OBJECTIVE In clinical practice, malocclusion is often encountered during the period of growth and development of individuals. In addition to nutritional imbalance, some studies have found that mastication affects learning and memory ability. Tooth loss and masticatory hypofunction have been suggested as risk factors of Alzheimer disease. However, relatively little research has been done in developing animals. The present study evaluated the relationship between masticatory hypofunction and neuropathological changes of the hippocampus in developing rats. DESIGN Four-week-old Wistar rats were randomly divided into saline-injected and botulinum toxin type A (BTXA)-injected groups. After an experiment period of 4 weeks, the rats were sacrificed for evaluation of neuropathological changes in the hippocampus through Nissl staining and phosphorylated cyclic AMP (cAMP) response element binding protein (CREB) immunohistochemistry. RESULTS Nissl staining revealed a significant reduction in the density of neurons in the BTXA-injected rats. The BTXA-injected rats exhibited a decreased level of CREB phosphorylation. The degree of p-CREB immunoreactivity differed significantly between the two groups. CONCLUSION The BTXA-injected rats exhibited a reduction in neuron density and phosphorylated CREB, indicating that mastication might influence the learning and memory ability during the growth period. Therefore, it is strongly suggested that malocclusion be corrected as soon as possible during growth and development.
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Affiliation(s)
- Chi-Yang Tsai
- Department of Orthodontics, Department of Dentistry, Taipei Medical University Hospital, Taipei, Taiwan; Graduate Institute of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan.
| | - Hsin-Ping Lee
- Department of Orthodontics, Department of Dentistry, Taipei Medical University Hospital, Taipei, Taiwan; Graduate Institute of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
| | - Hung-Ming Chang
- Department of Anatomy, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Fang-Chun Wu
- Department of Orthodontics, Department of Dentistry, Taipei Medical University Hospital, Taipei, Taiwan; Graduate Institute of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
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26
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Weijenberg RAF, Delwel S, Ho BV, van der Maarel-Wierink CD, Lobbezoo F. Mind your teeth-The relationship between mastication and cognition. Gerodontology 2018; 36:2-7. [PMID: 30480331 PMCID: PMC7380285 DOI: 10.1111/ger.12380] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 10/08/2018] [Accepted: 10/20/2018] [Indexed: 12/22/2022]
Abstract
This article explores the multifactorial relationship between mastication and cognition, with a focus on dementia. Older persons, especially those with dementia, are at great risk of suffering from oral health problems such as orofacial pain and loss of natural teeth. A possible explanation could be that the cognitive and motor impairments resulting from dementia cause a decrease in self‐care and as such, a worsening of oral health. An alternative explanation is that cognition and oral health influence each other. Animal studies show that a decrease in masticatory activity, for example, due to a soft diet or loss of teeth, causes memory loss and neuronal degeneration. The relationship between mastication and cognition has also been researched in human studies, but a cause‐effect relationship has not been proven. It is likely that multiple factors play a role in this relationship, such as self‐care, nutrition, stress and pain.
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Affiliation(s)
- Roxane A F Weijenberg
- Oral Kinesiology, Academisch Centrum Tandheelkunde Amsterdam, Amsterdam, The Netherlands
| | - Suzanne Delwel
- Oral Kinesiology, Academisch Centrum Tandheelkunde Amsterdam, Amsterdam, The Netherlands.,Clinical Neuropsychology, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Bach Van Ho
- Oral Kinesiology, Academisch Centrum Tandheelkunde Amsterdam, Amsterdam, The Netherlands
| | | | - Frank Lobbezoo
- Oral Kinesiology, Academisch Centrum Tandheelkunde Amsterdam, Amsterdam, The Netherlands
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27
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Shin MS, Shin YJ, Karna S, Kim HD. Rehabilitation of lost teeth related to maintenance of cognitive function. Oral Dis 2018; 25:290-299. [PMID: 30129990 DOI: 10.1111/odi.12960] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/05/2018] [Accepted: 07/30/2018] [Indexed: 11/27/2022]
Abstract
OBJECTIVE As the era of aging comes, cognitive impairment (CI) is increasing. The impact of rehabilitation of lost tooth on CI remains unclear. This study aimed to investigate whether non-rehabilitated lost teeth (NRLT) is associated with CI among Korean elders. METHODS A total of 280 elders comprising of 140 cases and 140 age-sex-matched controls were included in this cross-sectional study. CI was assessed using the Mini-Mental Status Examination (MMSE). NRLT was evaluated using panoramic radiograph and oral examination. NRLT was categorized into low (≤4) and high (≥5). Age, sex, education, drinking, smoking, exercise, obesity, hypertension, subclinical atherosclerosis, glucose, cholesterol, depression, and denture-wearing were considered as confounders. Conditional multivariate logistic regression analysis was applied to assess the adjusted association. RESULTS NRLT was associated with increased CI after controlling for confounders (odds ratio [OR] = 1.06, 95% confidence interval [95% CFI]: 1.00-1.13). However, lost teeth were not associated with CI. Those with high NRLT (≥5) compared to those with low NRLT (≤4) was more likely to have CI by 2.7 times (OR = 2.74, 95% CFI = 1.28-5.86). CONCLUSION Our data showed that NRLT was independently associated with CI. Hence, rehabilitation of the lost teeth could be important for the maintenance of cognitive function.
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Affiliation(s)
- Myung-Seop Shin
- Department of Preventive and Social Dentistry, School of Dentistry, Seoul National University, Seoul, Korea
| | - Yoo Jin Shin
- Department of Preventive and Social Dentistry, School of Dentistry, Seoul National University, Seoul, Korea.,BK21 PLUS Life Science, School of Dentistry, Seoul National University, Seoul, Korea
| | - Sandeep Karna
- Department of Preventive and Social Dentistry, School of Dentistry, Seoul National University, Seoul, Korea.,BK21 PLUS Life Science, School of Dentistry, Seoul National University, Seoul, Korea
| | - Hyun-Duck Kim
- Department of Preventive and Social Dentistry, School of Dentistry, Seoul National University, Seoul, Korea.,Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
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28
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Kubo KY, Kotachi M, Suzuki A, Iinuma M, Azuma K. Chewing during prenatal stress prevents prenatal stress-induced suppression of neurogenesis, anxiety-like behavior and learning deficits in mouse offspring. Int J Med Sci 2018; 15:849-858. [PMID: 30008596 PMCID: PMC6036092 DOI: 10.7150/ijms.25281] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/30/2018] [Indexed: 01/08/2023] Open
Abstract
Prenatal stress (PS) induces learning deficits and anxiety-like behavior in mouse pups by increasing corticosterone levels in the dam. We examined the effects of maternal chewing during PS on arginine vasopressin (AVP) mRNA expression in the dams and on neurogenesis, brain-derived neurotrophic factor (BDNF) mRNA expression, learning deficits and anxiety-like behavior in the offspring. Mice were divided into control, stress and stress/chewing groups. Pregnant mice were exposed to restraint stress beginning on day 12 of pregnancy and continuing until delivery. Mice in the stress/chewing group were given a wooden stick to chew during restraint stress. PS significantly increased AVP mRNA expression in the paraventricular nucleus (PVN) of the hypothalamus in the dams. PS also impaired learning ability, suppressed neurogenesis and BDNF mRNA expression in the hippocampus, and induced anxiety-like behavior in the offspring. Chewing during PS prevented the PS-induced increase in AVP mRNA expression of the PVN in the dams. Chewing during PS significantly attenuated the PS-induced learning deficits, anxiety-like behavior, and suppression of neurogenesis and BDNF mRNA expression in the hippocampus of the offspring. Chewing during PS prevented the increase in plasma corticosterone in the dam by inhibiting the hypothalamic-pituitary-adrenal axis activity, and attenuated the attenuated the PS-induced suppression of neurogenesis and BDNF expression in the hippocampus of the pups, thereby ameliorating the PS-induced learning deficits and anxiety-like behavior. Chewing during PS is an effective stress-coping method for the dam to prevent PS-induced deficits in learning ability and anxiety-like behavior in the offspring.
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Affiliation(s)
- Kin-ya Kubo
- Graduate School of Human Life Science, Nagoya Women's University, 3-40 Shioji-cho, Mizuho-ku, Nagoya, Aichi, 467-8610, Japan
| | - Mika Kotachi
- Departments of 2 Pediatric Dentistry, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan
| | - Ayumi Suzuki
- Departments of 2 Pediatric Dentistry, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan
| | - Mitsuo Iinuma
- Departments of 2 Pediatric Dentistry, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan
| | - Kagaku Azuma
- Department of Anatomy, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyusyu, 807-8555, Japan
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29
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Lin CS. Revisiting the link between cognitive decline and masticatory dysfunction. BMC Geriatr 2018; 18:5. [PMID: 29304748 PMCID: PMC5756393 DOI: 10.1186/s12877-017-0693-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 12/18/2017] [Indexed: 12/17/2022] Open
Abstract
Age-related decline in cognitive functions and dementia are major challenges in geriatric healthcare. Accumulating evidence from clinical, epidemiological and animal research suggests that tooth loss may be a risk factor for the decline of cognitive functions. This issue highlights the role of the brain-stomatognathic axis in geriatric medicine. Whether input from the stomatognathic apparatus can affect the brain remains an open debate. By revisiting the evidence published in the past five years, we argue that the hypothesis regarding the association between cognitive decline and masticatory dysfunction should be carefully interpreted. Most of the available clinical and epidemiological studies present only cross-sectional data. With respect to the prospective studies, important confounding factors, such as nutritional and physical conditions, were not fully controlled for. Animal research has revealed that hippocampal deficits may play key roles in the observed cognitive decline. However, experimental intervention and outcome assessments may not capture the condition of human subjects. Brain neuroimaging research may be suitable for bridging the gap between clinical and animal research, potentially contributing to (a) the clarification of the brain network associated with mastication, (b) the identification of brain imaging markers for exploring the mechanisms underlying long-term changes in masticatory functions, and (c) the elucidation of interactions between mastication and other cognitive-affective processing systems. Three potential models of the brain-stomatognathic axis and relevant hypotheses are summarized, focusing on the sensory feedback mechanisms, the compensation of motor control, and cerebellar deficits. Finally, we highlight four critical aspects of study and experimental design that should be considered in future research: (a) the refinement of the considered behavioral assessments, (b) the inclusion of baseline changes in mental and physical conditions,
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Affiliation(s)
- Chia-Shu Lin
- Department of Dentistry, School of Dentistry, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Taipei, 11221, Taiwan.
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30
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Noguchi T, Utsugi C, Kashiwayanagi M. Soft-diet feeding impairs neural transmission between mitral cells and interneurons in the mouse olfactory bulb. Arch Oral Biol 2017; 83:209-213. [PMID: 28802192 DOI: 10.1016/j.archoralbio.2017.07.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 07/21/2017] [Accepted: 07/23/2017] [Indexed: 11/15/2022]
Abstract
(Objective) The subventricular zone in mice generates a lot of neuroblasts even during adulthood. These neuroblasts migrate to the olfactory bulb and differentiate into inhibitory interneurons such as granule cells and periglomerular cells. Olfactory sensory neurons receive information from various odorants and transmit it to the olfactory bulb. Our previous study showed that soft-diet feeding impairs neurogenesis in the subventricular zone, in turn leading to the reduction of odor-induced behaviors and Fos-immunoreactivities, the latter of which are markers of neural activity, at the olfactory bulb after exposure to odors. Release of GABA from inhibitory interneurons at the olfactory bulb induces inhibitory currents at the mitral cells, which are output neurons from the olfactory bulb. (Design) In the present study, we measured spontaneous inhibitory postsynaptic currents (sIPSCs) at the mitral cells of mice fed a soft diet in order to explore the effects of changes in texture of diets on neural function at the olfactory bulb. (Results) The soft-diet feeding extended the intervals between sIPSCs and reduced their peak amplitudes. (Conclusions) The present results suggest that soft-diet feeding in mice attenuates the neural functions of inhibitory interneurons at the olfactory bulb.
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Affiliation(s)
- Tomohiro Noguchi
- Department of Sensory Physiology, Asahikawa Medical University, 078-8510 Asahikawa, Japan
| | - Chizuru Utsugi
- Dental Asahikawa Association Douhoku Oral Health Center, 070-0029 Asahikawa, Japan
| | - Makoto Kashiwayanagi
- Department of Sensory Physiology, Asahikawa Medical University, 078-8510 Asahikawa, Japan.
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31
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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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32
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Kim D, Chung S, Lee SH, Choi SY, Kim SM, Koo J, Lee JH, Jahng JW. Decreased hippocampal brain-derived neurotrophic factor and impaired cognitive function by hypoglossal nerve transection in rats. J Cell Mol Med 2017; 21:3752-3760. [PMID: 28767193 PMCID: PMC5706565 DOI: 10.1111/jcmm.13284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 05/22/2017] [Indexed: 12/21/2022] Open
Abstract
The hypoglossal nerve controls tongue movements, and damages of it result in difficulty in mastication and food intake. Mastication has been reported to maintain hippocampus‐dependent cognitive function. This study was conducted to examine the effect of tongue motor loss on the hippocampus‐dependent cognitive function and its underlying mechanism. Male Sprague Dawley rats were subjected to the initial training of Morris water maze task before or after the bilateral transection of hypoglossal nerves (Hx). When the initial training was given before the surgery, the target quadrant dwelling time during the probe test performed at a week after the surgery was significantly reduced in Hx rats relative to sham‐operated controls. When the initial training was given after the surgery, Hx affected the initial and reversal trainings and probe tests. Brain‐derived neurotrophic factor (BDNF) expression, cell numbers and long‐term potentiation (LTP) were examined in the hippocampus on the 10th day, and BrdU and doublecortin staining on the 14th day, after the surgery. Hx decreased the hippocampal BDNF and cells in the CA1/CA3 regions and impaired LTP. BrdU and doublecortin staining was decreased in the dentate gyrus of Hx rats. Results suggest that tongue motor loss impairs hippocampus‐dependent cognitive function, and decreased BDNF expression in the hippocampus may be implicated in its underlying molecular mechanism in relation with decreased neurogenesis/proliferation and impaired LTP.
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Affiliation(s)
- Doyun Kim
- Department of Oral and Maxillofacial Surgery, Dental Research Institute, Seoul National University, School of Dentistry, Seoul, Korea.,Department of Brain Science, Daegu Gyeongbuk Institute of Science & Technology, Dae Gu, Korea
| | - Sena Chung
- Department of Oral and Maxillofacial Surgery, Dental Research Institute, Seoul National University, School of Dentistry, Seoul, Korea
| | - Seung-Hyun Lee
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea
| | - Se-Young Choi
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea
| | - Soung-Min Kim
- Department of Oral and Maxillofacial Surgery, Dental Research Institute, Seoul National University, School of Dentistry, Seoul, Korea
| | - JaeHyung Koo
- Department of Brain Science, Daegu Gyeongbuk Institute of Science & Technology, Dae Gu, Korea
| | - Jong-Ho Lee
- Department of Oral and Maxillofacial Surgery, Dental Research Institute, Seoul National University, School of Dentistry, Seoul, Korea
| | - Jeong Won Jahng
- Department of Oral and Maxillofacial Surgery, Dental Research Institute, Seoul National University, School of Dentistry, Seoul, Korea
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33
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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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Pérez-Martín M, Rivera P, Blanco E, Lorefice C, Decara J, Pavón FJ, Serrano A, Rodríguez de Fonseca F, Suárez J. Environmental Enrichment, Age, and PPARα Interact to Regulate Proliferation in Neurogenic Niches. Front Neurosci 2016; 10:89. [PMID: 27013951 PMCID: PMC4783391 DOI: 10.3389/fnins.2016.00089] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/22/2016] [Indexed: 11/13/2022] Open
Abstract
Peroxisome proliferator-activated receptor alpha (PPARα) ligands have been shown to modulate recovery after brain insults such as ischemia and irradiation by enhancing neurogenesis. In the present study, we investigated the effect of the genetic deletion of PPARα receptors on the proliferative rate of neural precursor cells (NPC) in the adult brain. The study was performed in aged Pparα−/− mice exposed to nutritional (treats) and environmental (games) enrichments for 20 days. We performed immunohistochemical analyses of cells containing the replicating cell DNA marker 5-bromo-2′-deoxyuridine (BrdU+) and the immature neuronal marker doublecortin (Dcx+) in the main neurogenic zones of the adult brain: subgranular zone of dentate gyrus (SGZ), subventricular zone of lateral ventricles (SVZ), and/or hypothalamus. Results indicated a reduction in the number of BrdU+ cells in the neurogenic zones analyzed as well as Dcx+ cells in the SGZ during aging (2, 6, and 18 months). Pparα deficiency alleviated the age-related reduction of NPC proliferation (BrdU+ cells) in the SVZ of the 18-months-old mice. While no genotype effect on NPC proliferation was detected in the SGZ during aging, an accentuated reduction in the number of Dcx+ cells was observed in the SGZ of the 6-months-old Pparα−/− mice. Exposing the 18-months-old mice to nutritional and environmental enrichments reversed the Pparα−/−-induced impairment of NPC proliferation in the neurogenic zones analyzed. The enriched environment did not modify the number of SGZ Dcx+ cells in the 18 months old Pparα−/− mice. These results identify PPARα receptors as a potential target to counteract the naturally observed decline in adult NPC proliferation associated with aging and impoverished environments.
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Affiliation(s)
- Margarita Pérez-Martín
- Departamento de Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga Málaga, Spain
| | - Patricia Rivera
- UGC Salud Mental, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga-Hospital Universitario Regional de Málaga Málaga, Spain
| | - Eduardo Blanco
- UGC Salud Mental, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga-Hospital Universitario Regional de MálagaMálaga, Spain; Departament de Pedagogia i Psicologia, Facultat d'Educació, Psicologia i Treball Social, Universitat de LleidaLleida, Spain
| | - Clara Lorefice
- Departamento de Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga, Universidad de MálagaMálaga, Spain; UGC Salud Mental, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga-Hospital Universitario Regional de MálagaMálaga, Spain
| | - Juan Decara
- UGC Salud Mental, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga-Hospital Universitario Regional de Málaga Málaga, Spain
| | - Francisco J Pavón
- UGC Salud Mental, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga-Hospital Universitario Regional de Málaga Málaga, Spain
| | - Antonia Serrano
- UGC Salud Mental, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga-Hospital Universitario Regional de Málaga Málaga, Spain
| | - Fernando Rodríguez de Fonseca
- UGC Salud Mental, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga-Hospital Universitario Regional de Málaga Málaga, Spain
| | - Juan Suárez
- UGC Salud Mental, Instituto de Investigación Biomédica de Málaga, Universidad de Málaga-Hospital Universitario Regional de Málaga Málaga, Spain
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Mori D, Miyake H, Mizutani K, Shimpo K, Sonoda S, Yamamoto T, Fujiwara S, Kubo KY. Effects of occlusal disharmony on the hippocampal dentate gyrus in aged senescence-accelerated mouse prone 8 (SAMP8). Arch Oral Biol 2016; 65:95-101. [PMID: 26874024 DOI: 10.1016/j.archoralbio.2016.01.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/15/2015] [Accepted: 01/25/2016] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND OBJECTIVE Malocclusion induced by raising the bite causes chronic stress. Chronic stress leads to increased plasma corticosterone levels and impaired hippocampal function due to impaired neurogenesis or increased apoptosis in the hippocampus. The present study aimed to clarify the mechanisms underlying the impaired hippocampal function induced by the bite-raised condition in aged senescence-accelerated mouse prone 8 (SAMP8). DESIGN Nine-month-old aged SAMP8 mice were randomly divided into control and bite-raised groups. The vertical dimension of the bite was raised by applying resin to the molars. We evaluated newborn cell proliferation, survival, differentiation, and apoptosis in the hippocampal dentate gyrus (DG). Hippocampal brain-derived neurotrophic factor (BDNF) levels were also measured. RESULTS The bite-raised mice exhibited a significant decrease in proliferation, survival, and differentiation of newborn cells into neurons in the hippocampal DG compared with controls. The number of apoptotic cells in the hippocampal DG was increased at 7 and 14 days after the bite-raising procedure. Expression of BDNF protein and mRNA in the hippocampus was also decreased in the bite-raised mice. CONCLUSION Bite-raised aged SAMP8 mice exhibited decreased neurogenesis, increased apoptosis in the hippocampal DG, and decreased hippocampal BDNF expression, in association with hippocampus-dependent learning and memory deficits.
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Affiliation(s)
- Daisuke Mori
- Department of Prosthodontics, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu 501-0296, Japan
| | - Hidekazu Miyake
- Department of Prosthodontics, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu 501-0296, Japan
| | - Kenmei Mizutani
- Division of Biochemistry, Fujita Memorial Nanakuri Institute, Fujita Health University, 1865 Hisai-isshiki-cho, Tsu, Mie 514-1296, Japan
| | - Kan Shimpo
- Division of Biochemistry, Fujita Memorial Nanakuri Institute, Fujita Health University, 1865 Hisai-isshiki-cho, Tsu, Mie 514-1296, Japan
| | - Shigeru Sonoda
- Division of Biochemistry, Fujita Memorial Nanakuri Institute, Fujita Health University, 1865 Hisai-isshiki-cho, Tsu, Mie 514-1296, Japan
| | - Toshiharu Yamamoto
- Department of Human Biology, Kanagawa Dental College, 82 Inaoka-cho, Yokosuka, Kanagawa 238-8580, Japan
| | - Shuu Fujiwara
- Department of Prosthodontics, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu 501-0296, Japan
| | - Kin-ya Kubo
- Seijoh University Graduate School of Health Care Studies, 2-172, Fukinodai, Tokai, Aichi, 476-8588, Japan.
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