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Levy G, Levin B, Engelhardt E. Advancing the Genetics of Lewy Body Disorders with Disease-Modifying Treatments in Mind. ADVANCED GENETICS (HOBOKEN, N.J.) 2022; 3:2200011. [PMID: 36911298 PMCID: PMC9993470 DOI: 10.1002/ggn2.202200011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 07/13/2022] [Indexed: 11/06/2022]
Abstract
In this article, a caveat for advancing the genetics of Lewy body disorders is raised, given the nosological controversy about whether to consider dementia with Lewy bodies (DLB) and Parkinson's disease (PD) as one entity or two separate entities. Using the framework of the sufficient and component causes model of causation, as further developed into an evolution-based model of causation, it is proposed that a disease of complex etiology is defined as having a relatively high degree of sharing of the component causes (a genetic or environmental factor), that is, a low degree of heterogeneity of the sufficient causes. Based on this definition, only if the sharing of component causes within each of two diseases is similar to their combined sharing can lumping be warranted. However, it is not known whether the separate and combined sharing are similar before conducting the etiologic studies. This means that lumping DLB and PD can be counterproductive as it can decrease the ability to detect component causes despite the potential benefit of conducting studies with larger sample sizes. In turn, this is relevant to the development of disease-modifying treatments, because non-overlapping causal genetic factors may result in distinct pathogenetic pathways providing promising targets for interventions.
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Affiliation(s)
| | - Bruce Levin
- Department of BiostatisticsMailman School of Public HealthColumbia UniversityNew York10032USA
| | - Eliasz Engelhardt
- Instituto de Neurologia Deolindo Couto and Instituto de PsiquiatriaUniversidade Federal do Rio de JaneiroRio de Janeiro22290‐140Brazil
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Wang K, Zhang C, Zhang B, Li G, Shi G, Cai Q, Huang M. Gut dysfunction may be the source of pathological aggregation of alpha-synuclein in the central nervous system through Paraquat exposure in mice. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 246:114152. [PMID: 36201918 DOI: 10.1016/j.ecoenv.2022.114152] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 09/29/2022] [Accepted: 10/02/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND One of the most common types of neurodegenerative diseases (NDDs) is Lewy body disease (LBD), which is characterized by excessive accumulation of α-synuclein (α-syn) in the neurons and affects around 6 million individuals globally. In recent years, due to the environmental factors that can affect the development of this condition, such as exposure to herbicides and pesticides, so it has become a younger disease. Currently, the vast majority of studies on the neurotoxic effects of paraquat (PQ) focus on the late mechanisms of neuronal-glial network regulation, and little is known about the early origins of this environmental factor leading to LBD. OBJECTIVE To observe the effect of PQ exposure on intestinal function and to explore the key components of communicating the gut-brain axis by establishing a mouse model. METHODS AND RESULTS In this study, C57BL/6J mice were treated by intraperitoneal injection of 15 mg/kg PQ to construct an LBD time-series model, and confirmed by neurobehavioral testing and pathological examination. After PQ exposure, on the one hand, we found that fecal particle counts and moisture content were abnormal. on the other hand, we found that the expression levels of colonic tight junction proteins decreased, the expression levels of inflammatory markers increased, and the diversity and abundance of gut microbiota altered. In addition, pathological aggregation of α-syn was consistent in the colon and midbrain, and the metabolism and utilization of short-chain fatty acids (SCFAs) were also markedly altered. This suggests that pathological α-syn and SCFAs form the gut may be key components of the communicating gut-brain axis. CONCLUSION In this PQ-induced mouse model, gut microbiota disruption, intestinal epithelial barrier damage, and inflammatory responses may be the main causes of gut dysfunction, and pathological α-syn and SCFAs in the gut may be key components of the communicating gut-brain axis.
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Affiliation(s)
- Kaidong Wang
- School of Public Health and Management, Ningxia Medical University, Yinchuan, Ningxia, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, Shengli Street, Xingqing District, Yinchuan, Ningxia, China
| | - Chunhui Zhang
- School of Public Health and Management, Ningxia Medical University, Yinchuan, Ningxia, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, Shengli Street, Xingqing District, Yinchuan, Ningxia, China
| | - Baofu Zhang
- School of Public Health and Management, Ningxia Medical University, Yinchuan, Ningxia, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, Shengli Street, Xingqing District, Yinchuan, Ningxia, China
| | - Guoliang Li
- School of Public Health and Management, Ningxia Medical University, Yinchuan, Ningxia, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, Shengli Street, Xingqing District, Yinchuan, Ningxia, China
| | - Ge Shi
- School of Public Health and Management, Ningxia Medical University, Yinchuan, Ningxia, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, Shengli Street, Xingqing District, Yinchuan, Ningxia, China
| | - Qian Cai
- School of Public Health and Management, Ningxia Medical University, Yinchuan, Ningxia, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, Shengli Street, Xingqing District, Yinchuan, Ningxia, China.
| | - Min Huang
- School of Public Health and Management, Ningxia Medical University, Yinchuan, Ningxia, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, Shengli Street, Xingqing District, Yinchuan, Ningxia, China.
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Levy G, Levin B, Engelhardt E. Echoes of William Gowers's concept of abiotrophy. JOURNAL OF THE HISTORY OF THE NEUROSCIENCES 2022; 31:425-449. [PMID: 34905460 DOI: 10.1080/0964704x.2021.1989649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Among William Gowers's many contributions to neurology, the concept of abiotrophy ("an essential failure of vitality") has been relatively overlooked. In this article, we review the echoes of Gowers's concept in neurology, ophthalmology, and aging research. We also argue that abiotrophy is broader than both heredodegeneration and neurodegeneration. Unlike the common view that it simply means premature aging, abiotrophy currently can be understood as a progressive degenerative process of a mature specialized tissue, which is nonsynchronous with normal aging and may affect organs or systems early in life, resulting from the age-dependent effects of genetic mutations or variants, even if environmental factors may also causally contribute to the process. Although the term has largely fallen out of use, there are likely to be everlasting echoes of Gowers's concept, through which he is to be considered a source of the modern thinking about the etiology and nosology of neurological diseases.
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Affiliation(s)
| | - Bruce Levin
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, New York, USA
| | - Eliasz Engelhardt
- Instituto de Neurologia Deolindo Couto and Instituto de Psiquiatria, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Levy G, Levin B. An Evolution-Based Model of Causation for Aging-Related Diseases and Intrinsic Mortality: Explanatory Properties and Implications for Healthy Aging. Front Public Health 2022; 10:774668. [PMID: 35252084 PMCID: PMC8894190 DOI: 10.3389/fpubh.2022.774668] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 01/10/2022] [Indexed: 01/07/2023] Open
Abstract
Aging-related diseases are the most prevalent diseases in advanced countries nowadays, accounting for a substantial proportion of mortality. We describe the explanatory properties of an evolution-based model of causation (EBMC) applicable to aging-related diseases and intrinsic mortality. The EBMC takes the sufficient and component causes model of causation as a starting point and develops it using evolutionary and statistical theories. Genetic component causes are classified as “early-onset” or “late-onset” and environmental component causes as “evolutionarily conserved” or “evolutionarily recent.” Genetic and environmental component causes are considered to occur as random events following time-to-event distributions, and sufficient causes are classified according to whether or not their time-to-event distributions are “molded” by the declining force of natural selection with increasing age. We obtain for each of these two groups different time-to-event distributions for disease incidence or intrinsic mortality asymptotically (i.e., for a large number of sufficient causes). The EBMC provides explanations for observations about aging-related diseases concerning the penetrance of genetic risk variants, the age of onset of monogenic vs. sporadic forms, the meaning of “age as a risk factor,” the relation between frequency and age of onset, and the emergence of diseases associated with the modern Western lifestyle. The EBMC also provides an explanation of the Gompertz mortality model at the fundamental level of genetic causes and involving evolutionary biology. Implications for healthy aging are examined under the scenarios of health promotion and postponed aging. Most importantly from a public health standpoint, the EBMC implies that primary prevention through changes in lifestyle and reduction of environmental exposures is paramount in promoting healthy aging.
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Affiliation(s)
- Gilberto Levy
- Independent Researcher, Rio de Janeiro, Brazil
- *Correspondence: Gilberto Levy
| | - Bruce Levin
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY, United States
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Simon C, Soga T, Okano HJ, Parhar I. α-Synuclein-mediated neurodegeneration in Dementia with Lewy bodies: the pathobiology of a paradox. Cell Biosci 2021; 11:196. [PMID: 34798911 PMCID: PMC8605528 DOI: 10.1186/s13578-021-00709-y] [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: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 11/16/2022] Open
Abstract
Dementia with Lewy bodies (DLB) is epitomized by the pathognomonic manifestation of α-synuclein-laden Lewy bodies within selectively vulnerable neurons in the brain. By virtue of prion-like inheritance, the α-synuclein protein inexorably undergoes extensive conformational metamorphoses and culminate in the form of fibrillar polymorphs, instigating calamitous damage to the brain's neuropsychological networks. This epiphenomenon is nebulous, however, by lingering uncertainty over the quasi "pathogenic" behavior of α-synuclein conformers in DLB pathobiology. Despite numerous attempts, a monolithic "α-synuclein" paradigm that is able to untangle the enigma enshrouding the clinicopathological spectrum of DLB has failed to emanate. In this article, we review conceptual frameworks of α-synuclein dependent cell-autonomous and non-autonomous mechanisms that are likely to facilitate the transneuronal spread of degeneration through the neuraxis. In particular, we describe how the progressive demise of susceptible neurons may evolve from cellular derangements perpetrated by α-synuclein misfolding and aggregation. Where pertinent, we show how these bona fide mechanisms may mutually accentuate α-synuclein-mediated neurodegeneration in the DLB brain.
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Affiliation(s)
- Christopher Simon
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
| | - Tomoko Soga
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
| | - Hirotaka James Okano
- Division of Regenerative Medicine, Research Center for Medical Sciences, The Jikei University School of Medicine, Tokyo, Japan
| | - Ishwar Parhar
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
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