1
|
Schubert CR, Paulsen AJ, Alex Pinto A, Chappell RJ, Chen Y, Ferrucci L, Hancock LM, Cruickshanks KJ, Merten N. Effect of Neurotoxin Exposure on Blood Biomarkers of Neurodegeneration and Alzheimer Disease. Alzheimer Dis Assoc Disord 2023; 37:310-314. [PMID: 37698523 PMCID: PMC10841324 DOI: 10.1097/wad.0000000000000579] [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: 12/19/2022] [Accepted: 07/25/2023] [Indexed: 09/13/2023]
Abstract
AIM To determine whether exposure to neurotoxins in midlife is associated with changes in blood-based biomarkers of neurodegeneration and Alzheimer disease pathology. METHODS Blood cadmium, lead, neurofilament light (NfL) chain, total tau (TTau), and amyloid beta (Aβ) 40 and Aβ42 concentrations were measured in 1516 participants in the Beaver Dam Offspring Study. Linear mixed-effect models were used to determine associations between baseline cadmium and lead levels and baseline NfL, TTau, and Aβ42/Aβ40, and 10-year change in concentrations using repeated measures of these biomarkers as the outcome. RESULTS In women, higher cadmium and lead levels were associated with higher baseline TTau concentrations. A higher baseline cadmium level was associated with lower baseline Aβ42/Aβ40 in both men and women. In age-sex-adjusted models, a doubling in baseline cadmium level was associated with a 0.2% (95% CI: 0.0, 0.3) higher increase per year in NfL concentrations. In men, a doubling of baseline lead level was associated with a 0.9% (95% CI: 0.1, 1.7) higher increase per year in TTau concentration. CONCLUSIONS Participants with relatively higher levels of cadmium and lead had blood biomarker concentrations consistent with more neuronal damage and Alzheimer disease pathology. Environmental exposure to neurotoxins may contribute to neurodegeneration.
Collapse
Affiliation(s)
- Carla R. Schubert
- Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, USA
| | - Adam J. Paulsen
- Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, USA
| | - A. Alex Pinto
- Department of Biostatistics and Medical Informatics, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, USA
| | - Richard J. Chappell
- Department of Biostatistics and Medical Informatics, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, USA
- Department of Statistics, School of Computer, Data & Information Sciences, University of Wisconsin - Madison, Madison, WI, USA
| | - Yanjun Chen
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, USA
| | - Luigi Ferrucci
- Longitudinal Study Section, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Laura M. Hancock
- Department of Neurology, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, USA
- William S. Middleton Memorial VA Medical Center, Madison, WI, USA
| | - Karen J. Cruickshanks
- Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, USA
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, USA
| | - Natascha Merten
- Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, USA
- Department of Medicine - Division of Geriatrics and Adult Development, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, USA
- Wisconsin Alzheimer’s Disease Research Center, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, USA
| |
Collapse
|
2
|
Shrestha S, Zhu X, Kamath V, Sullivan KJ, Deal JA, Sharrett AR, Schneider ALC, Palta P, Gottesman RF, Windham BG, Mosley TH, Griswold ME, Chen H. Factors Associated with Poor Olfaction and Olfactory Decline in Older Adults in the ARIC Neurocognitive Study. Nutrients 2023; 15:3641. [PMID: 37630831 PMCID: PMC10459162 DOI: 10.3390/nu15163641] [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: 07/17/2023] [Revised: 08/13/2023] [Accepted: 08/18/2023] [Indexed: 08/27/2023] Open
Abstract
Olfactory function has significant implications for human health, but few risk factors for olfactory decline have been identified. We examined the factors associated with olfactory status and decline over five years in the Atherosclerosis Risk in Communities (ARIC) Neurocognitive Study. A 12-item odor identification test was used to assess olfaction in 6053 participants in 2011-2013 (ARIC visit 5, mean age: 75.6, 41% male, 23% Black race) and in 3235 participants in 2016-2017 (visit 6). We used Poisson regression models to examine cross-sectional associations of a range of potential factors with the total odor identification errors (mean errors: 2.8 ± 2.4) in visit 5 participants. We used mixed-effect Poisson regression to examine associations with olfactory decline between visits 5 and 6. We also examined associations with visit 5 anosmia prevalence (847 cases, 14%) and incident anosmia between the two visits (510 cases, 16%) using Poisson models. Older age, male sex, lower education, Black race, APOE ε4 alleles, and diabetes were associated with higher odor identification errors and higher anosmia prevalence, and greater physical activity and hypertension with better olfaction. Age, male sex, lower education, Black race, APOE ε4 allele, and vitamin B12 levels were associated with incident anosmia over 5 years. Older age was associated with faster olfactory decline. Future studies with longer follow-ups are warranted.
Collapse
Affiliation(s)
- Srishti Shrestha
- The Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Xiaoqian Zhu
- The Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Vidyulata Kamath
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kevin J. Sullivan
- The Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Jennifer A. Deal
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - A. Richey Sharrett
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Andrea L. C. Schneider
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Priya Palta
- Department of Neurology, University of North Carolina Chapel Hill, Chapel Hill, NC 27599, USA
| | - Rebecca F. Gottesman
- Stroke Branch, National Institute of Neurological Disorders and Stroke Intramural Research Program, Bethesda, MD 20892, USA
| | - B. Gwen Windham
- The Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Thomas H. Mosley
- The Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Michael E. Griswold
- The Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Honglei Chen
- Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI 48824, USA
| |
Collapse
|
3
|
Schubert CR, Fischer ME, Pinto AA, Paulsen AJ, Chen Y, Huang GH, Klein BEK, Tsai MY, Merten N, Cruickshanks KJ. Inflammation, metabolic dysregulation and environmental neurotoxins and risk of cognitive decline and impairment in midlife. Neurol Sci 2023; 44:149-157. [PMID: 36114981 PMCID: PMC9825629 DOI: 10.1007/s10072-022-06386-0] [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: 05/25/2022] [Accepted: 09/03/2022] [Indexed: 01/11/2023]
Abstract
BACKGROUND Age-related declines in cognitive function may begin in midlife. PURPOSE To determine whether blood-based biomarkers of inflammation, metabolic dysregulation and neurotoxins are associated with risk of cognitive decline and impairment. METHODS Baseline blood samples from the longitudinal Beaver Dam Offspring Study (2005-2008) were assayed for markers of inflammation, metabolic dysregulation, and environmental neurotoxins. Cognitive function was measured at baseline, 5-year (2010-2013) and 10-year (2015-2017) examinations. Participants without cognitive impairment at baseline and with cognitive data from at least one follow-up were included. Cox proportional hazards models were used to evaluate associations between baseline blood biomarkers and the 10-year cumulative incidence of cognitive impairment. Poisson models were used to estimate the relative risk (RR) of 5-year decline in cognitive function by baseline blood biomarkers. Models were adjusted for age, sex, education, and cardiovascular related risk factors. RESULTS Participants (N = 2421) were a mean age of 49 years and 55% were women. Soluble vascular cell adhesion molecule-1 (sVCAM-1Tertile(T)3 vs T1-2 hazard ratio (HR) = 1.72, 95% confidence interval (CI) = 1.05,2.82) and hemoglobin A1C (HR = 1.75, 95% CI = 1.18,2.59, per 1% in women) were associated with the 10-year cumulative incidence of cognitive impairment. sVCAM-1 (RRT3 vs T1-2 = 1.45, 95% CI = 1.06,1.99) and white blood cell count (RR = 1.10, 95% CI = 1.02,1.19, per 103/μL) were associated with 5-year cognitive decline. CONCLUSIONS Biomarkers related to inflammation and metabolic dysregulation were associated with an increased risk of developing cognitive decline and impairment. These results extend previous research in cognitive aging to early markers of cognitive decline in midlife, a time when intervention methods may be more efficacious.
Collapse
Affiliation(s)
- Carla R Schubert
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Rm 1087 WARF, 610 Walnut Street, Madison, WI, 53726, USA.
| | - Mary E Fischer
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Rm 1087 WARF, 610 Walnut Street, Madison, WI, 53726, USA
| | - A Alex Pinto
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Rm 1087 WARF, 610 Walnut Street, Madison, WI, 53726, USA
| | - Adam J Paulsen
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Rm 1087 WARF, 610 Walnut Street, Madison, WI, 53726, USA
| | - Yanjun Chen
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Rm 1087 WARF, 610 Walnut Street, Madison, WI, 53726, USA
| | - Guan-Hua Huang
- Institute of Statistics, National Yang Ming Chiao Tung University, 1001 University Road, Hsinchu, 30010, Taiwan
| | - Barbara E K Klein
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Rm 1087 WARF, 610 Walnut Street, Madison, WI, 53726, USA
| | - Michael Y Tsai
- Department of Laboratory Medicine and Pathology, University of Minnesota, 420 Delaware Street S.E, Minneapolis, MN, 55455, USA
| | - Natascha Merten
- Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, 610 Walnut Street, Madison, WI, 53726, USA
- Division of Geriatrics and Gerontology, Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Alzheimer's Disease Research Center, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Karen J Cruickshanks
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Rm 1087 WARF, 610 Walnut Street, Madison, WI, 53726, USA
- Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, 610 Walnut Street, Madison, WI, 53726, USA
| |
Collapse
|
4
|
Paulsen AJ, Schubert CR, Pinto AA, Chappell RJ, Chen Y, Cruickshanks KJ, Engelman CD, Ferrucci L, Hancock LM, Johnson SC, Merten N. Associations of sensory and motor function with blood-based biomarkers of neurodegeneration and Alzheimer's disease in midlife. Neurobiol Aging 2022; 120:177-188. [PMID: 36209638 PMCID: PMC9613601 DOI: 10.1016/j.neurobiolaging.2022.08.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 08/12/2022] [Accepted: 08/17/2022] [Indexed: 10/15/2022]
Abstract
Pathological biomarkers of dementia and Alzheimer's disease (AD) change decades before clinical symptoms. Common sensory and motor changes in aging adults may be early markers of neurodegeneration. We investigated if midlife sensory and motor functions in Beaver Dam Offspring Study (BOSS) participants (N = 1529) were associated with longitudinal changes in blood-based biomarkers of neurodegeneration (neurofilament light chain (NfL); total tau (TTau)) and AD (amyloid beta (Aβ)). Mixed-effects models with baseline sensory and motor function as determinants and 10-year biomarker change as outcome were used. Participants with hearing impairment and worse motor function (among women) showed faster increases in NfL level over time (0.8% per year; 0.3% per year, respectively). There were no significant associations with TTau or Aβ. We found consistent relationships between worse baseline hearing and motor function with a faster increase in neurodegeneration, specifically serum NfL level. Future studies with longer follow-up should determine if sensory and motor changes are more reflective of general neurodegeneration than AD-specific pathology and whether sensory and motor tests may be useful screening tools for neurodegeneration risk.
Collapse
Affiliation(s)
- Adam J Paulsen
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA.
| | - Carla R Schubert
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Alex A Pinto
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Richard J Chappell
- Department of Biostatistics and Medical Informatics and Department of Statistics, University of Wisconsin, Madison, WI, USA
| | - Yanjun Chen
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Karen J Cruickshanks
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA; Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Corinne D Engelman
- Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Luigi Ferrucci
- Longitudinal Study Section, Intramural Research Program, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Laura M Hancock
- Department of Neurology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Sterling C Johnson
- Alzheimer's Disease Research Center and Wisconsin Alzheimer's Institute, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA; Geriatric Research Education and Clinical Center of the William S. Middleton Memorial Veterans Hospital, Madison, WI, USA
| | - Natascha Merten
- Department of Geriatrics and Adult Development, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| |
Collapse
|
5
|
Liu C, Zhang R, Yang L, Ji T, Zhu C, Liu B, Zhang H, Xu C, Zhang N, Huang S, Chen L. Neuroprotection of resveratrol against cadmium-poisoning acts through dual inhibition of mTORC1/2 signaling. Neuropharmacology 2022; 219:109236. [PMID: 36049535 PMCID: PMC9524506 DOI: 10.1016/j.neuropharm.2022.109236] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 08/07/2022] [Accepted: 08/22/2022] [Indexed: 11/29/2022]
Abstract
Resveratrol is a natural polyphenol with neuroprotective function. The underlying mechanism is not well understood. Our previous studies have identified that resveratrol antagonizes cadmium (Cd) neurotoxicity via targeting PP2A/PP5-mediated Erk1/2 and JNK pathways. Here we show that resveratrol protected against Cd-poisoning also by blocking Cd-induced activation of mTORC1 and mTORC2 pathways in PC12 cells and murine primary neurons. Co-treatment with inhibitors of mTORC1 (rapamycin), mTORC1/2 (PP242), Erk1/2 (U0126) and/or JNK (SP600125), knockdown of mTOR, or disruption of mTORC1 and/or mTORC2 by silencing raptor, rictor or raptor/rictor, respectively, markedly potentiated the inhibitory effects of resveratrol on Cd-induced phosphorylation of S6K1/4E-BP1 (mTORC1 substrates), Akt (mTORC2 substrate), Erk1/2 and/or JNK/c-Jun, cleavage of caspase-3 and cell death in PC12 cells and/or primary neurons. Knockdown of S6K1 or 4E-BP1, or ectopic expression of constitutively hypophosphorylated 4E-BP1 (4E-BP1-5A) reinforced the resveratrol's inhibition on Cd-evoked cell death, whereas ectopic expression of constitutively active S6K1 or knockdown of 4E-BP1 attenuated the resveratrol's inhibition on Cd-induced cell death. Co-treatment with Akt inhibitor or overexpression of dominant negative Akt (dn-Akt) strengthened the resveratrol's suppression on Cd-induced ROS, Erk1/2 activation and apoptosis, whereas overexpression of constitutively active Akt (myr-Akt) conferred high resistance to the resveratrol's inhibitory effects in the neuronal cells. Taken together, the results indicate that resveratrol attenuates Cd-induced neuronal apoptosis partly through inhibition of mTORC1/2 pathways. Our studies highlight that resveratrol can be exploited for the prevention of Cd toxicity related to neurodegenerative diseases.
Collapse
Affiliation(s)
- Chunxiao Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, PR China; Department of Medical Technology, Suzhou Vocational Health College, Suzhou, 215009, PR China
| | - Ruijie Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, PR China; College of Life Sciences, Anhui Medical University, Anhui, 230032, PR China
| | - Liu Yang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, PR China
| | - Tong Ji
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, PR China
| | - Cuilan Zhu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, PR China
| | - Beibei Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, PR China
| | - Hai Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, PR China
| | - Chong Xu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, PR China
| | - Nana Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, PR China
| | - Shile Huang
- Department of Biochemistry and Molecular Biology, Shreveport, LA, 71130-3932, USA; Department of Hematology and Oncology, Shreveport, LA, 71130-3932, USA; Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, 71130-3932, USA.
| | - Long Chen
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, PR China.
| |
Collapse
|
6
|
The pupil constriction to light is associated with cognitive measures in middle-aged and older adults. Aging Clin Exp Res 2022; 34:1655-1662. [PMID: 35267180 DOI: 10.1007/s40520-022-02097-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/16/2022] [Indexed: 11/01/2022]
Abstract
AIMS The evidence relating the pupil light reflex (PLR) and cognition have been inconsistent. In this cross-sectional study, we evaluated the association between the PLR and cognition in community-dwelling middle-aged and older individuals. METHODS Pupil reactivity was recorded in a subgroup of 403 participants (mean age 60.7 years, 57.3% females) in an epidemiologic study of aging. Ten pupil parameters were calculated to describe pupil constriction to light stimuli. A principal component analysis (PCA) score was used to calculate an overall performance over four cognitive testings. Linear regression was used to assess the association between pupil parameters and PCA scores, adjusting for age, sex, education, medications, health-related quality of life questionnaire, and systemic and ocular comorbidities. RESULTS The PCA scores decreased by 0.039 [95% CI (- 0.050, - 0.028)] per year increase in age and were lower in males than females by 0.76 [95% CI (- 0.96, - 0.55)] (p < 0.001). Pupil constriction amplitude in millimeters and the duration from stimulus onset to maximal constriction velocity were significantly associated with cognition after adjusting for (1) age and sex and (2) age, sex, and multiple covariates (p < 0.05). CONCLUSIONS In this study, we provided moderate evidence suggesting the association between PLR and neuropsychological cognitive measures. The findings suggest the potential of pupil reactivity to serve as a biomarker of brain aging and warrant further longitudinal study to assess if changes in the PLR can predict cognitive decline over time.
Collapse
|
7
|
Chen H, Wang K, Scheperjans F, Killinger B. Environmental triggers of Parkinson's disease - Implications of the Braak and dual-hit hypotheses. Neurobiol Dis 2022; 163:105601. [PMID: 34954321 PMCID: PMC9525101 DOI: 10.1016/j.nbd.2021.105601] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/05/2021] [Accepted: 12/22/2021] [Indexed: 11/22/2022] Open
Abstract
Idiopathic Parkinson's disease (PD) may take decades to develop, during which many risk or protective factors may come into play to initiate the pathogenesis or modify its progression to clinical PD. The lack of understanding of this prodromal phase of PD and the factors involved has been a major hurdle in the study of PD etiology and preventive strategies. Although still controversial, the Braak and dual-hit hypotheses that PD may start peripherally in the olfactory structures and/or the gut provides a theoretical platform to identify the triggers and modifiers of PD prodromal development and progression. This is particularly true for the search of environmental causes of PD as the olfactory structures and gut are the major human mucosal interfaces with the environment. In this review, we lay out our personal views about how the Braak and dual-hit hypotheses may help us search for the environmental triggers and modifiers for PD, summarize available experimental and epidemiological evidence, and discuss research gaps and strategies.
Collapse
Affiliation(s)
- Honglei Chen
- Epidemiology and Biostatistics, College of Human Medicine, Michigan State University, East Lansing, MI 48824, USA.
| | - Keran Wang
- Epidemiology and Biostatistics, College of Human Medicine, Michigan State University, East Lansing, MI 48824, USA
| | - Filip Scheperjans
- Department of Neurology, Helsinki University Hospital, and Clinicum, University of Helsinki, Haartmaninkatu 4, 00290 Helsinki, Finland
| | - Bryan Killinger
- Graduate College, Rush University Medical Center, Chicago, IL 60612, USA
| |
Collapse
|
8
|
AlMatrouk A, Lemons K, Ogura T, Lin W. Modification of the Peripheral Olfactory System by Electronic Cigarettes. Compr Physiol 2021; 11:2621-2644. [PMID: 34661289 DOI: 10.1002/cphy.c210007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Electronic cigarettes (e-cigs) are used by millions of adolescents and adults worldwide. Commercial e-liquids typically contain flavorants, propylene glycol, and vegetable glycerin with or without nicotine. These chemical constituents are detected and evaluated by chemosensory systems to guide and modulate vaping behavior and product choices of e-cig users. The flavorants in e-liquids are marketing tools. They evoke sensory percepts of appealing flavors through activation of chemical sensory systems to promote the initiation and sustained use of e-cigs. The vast majority of flavorants in e-liquids are volatile odorants, and as such, the olfactory system plays a dominant role in perceiving these molecules that enter the nasal cavity either orthonasally or retronasally during vaping. In addition to flavorants, e-cig aerosol contains a variety of by-products generated through heating the e-liquids, including odorous irritants, toxicants, and heavy metals. These harmful substances can directly and adversely impact the main olfactory epithelium (MOE). In this article, we first discuss the olfactory contribution to e-cig flavor perception. We then provide information on MOE cell types and their major functions in olfaction and epithelial maintenance. Olfactory detection of flavorants, nicotine, and odorous irritants and toxicants are also discussed. Finally, we discuss the cumulated data on modification of the MOE by flavorant exposure and toxicological impacts of formaldehyde, acrolein, and heavy metals. Together, the information presented in this overview may provide insight into how e-cig exposure may modify the olfactory system and adversely impact human health through the alteration of the chemosensory factor driving e-cig use behavior and product selections. © 2021 American Physiological Society. Compr Physiol 11:2621-2644, 2021.
Collapse
Affiliation(s)
- Abdullah AlMatrouk
- General Department of Criminal Evidence, Forensic Laboratories, Ministry of Interior, Farwaniyah, Kuwait.,Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Kayla Lemons
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, North Carolina, USA.,Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Tatsuya Ogura
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Weihong Lin
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, USA
| |
Collapse
|