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Kondo K, Kikuta S, Ueha R, Suzukawa K, Yamasoba T. Age-Related Olfactory Dysfunction: Epidemiology, Pathophysiology, and Clinical Management. Front Aging Neurosci 2020; 12:208. [PMID: 32733233 PMCID: PMC7358644 DOI: 10.3389/fnagi.2020.00208] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/12/2020] [Indexed: 12/21/2022] Open
Abstract
Like other sensory systems, olfactory function deteriorates with age. Epidemiological studies have revealed that the incidence of olfactory dysfunction increases at the age of 60 and older and males are more affected than females. Moreover, smoking, heavy alcohol use, sinonasal diseases, and Down’s syndrome are associated with an increased incidence of olfactory dysfunction. Although the pathophysiology of olfactory dysfunction in humans remains largely unknown, studies in laboratory animals have demonstrated that both the peripheral and central olfactory nervous systems are affected by aging. Aged olfactory neuroepithelium in the nasal cavity shows the loss of mature olfactory neurons, replacement of olfactory neuroepithelium by respiratory epithelium, and a decrease in basal cell proliferation both in the normal state and after injury. In the central olfactory pathway, a decrease in the turnover of interneurons in the olfactory bulb (OB) and reduced activity in the olfactory cortex under olfactory stimulation is observed. Recently, the association between olfactory impairment and neurodegenerative diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD), has gained attention. Evidence-based pharmacotherapy to suppress or improve age-related olfactory dysfunction has not yet been established, but preliminary results suggest that olfactory training using odorants may be useful to improve some aspects of age-related olfactory impairment.
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Affiliation(s)
- Kenji Kondo
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shu Kikuta
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Rumi Ueha
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Keigo Suzukawa
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tatsuya Yamasoba
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
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Lee TK, Chen BH, Lee JC, Shin MC, Cho JH, Lee HA, Choi JH, Hwang IK, Kang IJ, Ahn JH, Park JH, Choi SY, Won MH. Age‑dependent decreases in insulin‑like growth factor‑I and its receptor expressions in the gerbil olfactory bulb. Mol Med Rep 2018; 17:8161-8166. [PMID: 29658594 PMCID: PMC5983990 DOI: 10.3892/mmr.2018.8886] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 04/06/2018] [Indexed: 12/23/2022] Open
Abstract
Insulin-like growth factor-I (IGF-I) is a multifunctional protein present in the central nervous system. A number of previous studies have revealed alterations in IGF-I and its receptor (IGF-IR) expression in various regions of the brain. However, there are few reports on age-dependent alterations in IGF-I and IGF-IR expressions in the olfactory bulb, which contains the secondary neurons of the olfactory system. The present study examined the cellular morphology in the olfactory bulb by using cresyl violet (CV) staining at postnatal month (PM) 3 in the young group, PM 6 in the adult group and PM 24 in the aged group in gerbils. In addition, detailed examinations were performed of the protein levels and immunoreactivities of IGF-I and IGF-IR in the olfactory bulb in each group. There were no significant changes in the cellular morphology between the three groups. The protein levels and immunoreactivities of the IGF-I and IGF-IR were the highest in the young group and they decreased with age. He protein levels and immunoreactivities of the IGF-I and IGF-IR were the lowest in the aged group. In brief, our results indicate that IGF-I and IGF-IR expressions are strong in young olfactory bulbs and significantly reduced in aged olfactory bulbs. In conclusion, subsequent decreases in IGF-I and IGF-IR expression with age may be associated with olfactory decline. Further studies are required to investigate the roles of IFG-I and IGF-IR in disorders of the olfactory system.
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Affiliation(s)
- Tae-Kyeong Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Bai Hui Chen
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Jae-Chul Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Myoung Cheol Shin
- Department of Emergency Medicine, School of Medicine, Chuncheon, Gangwon 24341, Republic of Korea
| | - Jun Hwi Cho
- Department of Emergency Medicine, School of Medicine, Chuncheon, Gangwon 24341, Republic of Korea
| | - Hyang-Ah Lee
- Department of Obstetrics and Gynecology, School of Medicine, Chuncheon, Gangwon 24341, Republic of Korea
| | - Jung Hoon Choi
- Department of Anatomy, College of Veterinary Medicine, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Il Jun Kang
- Department of Food Science and Nutrition, Hallym University, Chuncheon, Gangwon 24252, Republic of Korea
| | - Ji Hyeon Ahn
- Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Gangwon 24252, Republic of Korea
| | - Joon Ha Park
- Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Gangwon 24252, Republic of Korea
| | - Soo Young Choi
- Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Gangwon 24252, Republic of Korea
| | - Moo-Ho Won
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
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Nam SM, Choi JH, Yoo DY, Kim W, Jung HY, Kim JW, Yoo M, Lee S, Kim CJ, Yoon YS, Hwang IK. Effects of curcumin (Curcuma longa) on learning and spatial memory as well as cell proliferation and neuroblast differentiation in adult and aged mice by upregulating brain-derived neurotrophic factor and CREB signaling. J Med Food 2014; 17:641-9. [PMID: 24712702 DOI: 10.1089/jmf.2013.2965] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Aging is a progressive process, and it may lead to the initiation of neurological diseases. In this study, we investigated the effects of wild Indian Curcuma longa using a Morris water maze paradigm on learning and spatial memory in adult and D-galactose-induced aged mice. In addition, the effects on cell proliferation and neuroblast differentiation were assessed by immunohistochemistry for Ki67 and doublecortin (DCX) respectively. The aging model in mice was induced through the subcutaneous administration of D-galactose (100 mg/kg) for 10 weeks. C. longa (300 mg/kg) or its vehicle (physiological saline) was administered orally to adult and D-galactose-treated mice for the last three weeks before sacrifice. The administration of C. longa significantly shortened the escape latency in both adult and D-galactose-induced aged mice and significantly ameliorated D-galactose-induced reduction of cell proliferation and neuroblast differentiation in the subgranular zone of hippocampal dentate gyrus. In addition, the administration of C. longa significantly increased the levels of phosphorylated CREB and brain-derived neurotrophic factor in the subgranular zone of dentate gyrus. These results indicate that C. longa mitigates D-galactose-induced cognitive impairment, associated with decreased cell proliferation and neuroblast differentiation, by activating CREB signaling in the hippocampal dentate gyrus.
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Affiliation(s)
- Sung Min Nam
- 1 Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University , Seoul, South Korea
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