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González-Márquez C. Neuromodulation and memory: exploring ethical ramifications in memory modification treatment via implantable neurotechnologies. Front Psychol 2023; 14:1282634. [PMID: 38179489 PMCID: PMC10764565 DOI: 10.3389/fpsyg.2023.1282634] [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: 08/24/2023] [Accepted: 11/17/2023] [Indexed: 01/06/2024] Open
Abstract
Invasive implantable neurotechnologies capable of simultaneously altering and recording neural activity are no longer the exclusive province of science fiction but a looming reality that will revolutionize medical practice. These advancements, particularly in their memory-altering capabilities, herald a vast array of opportunities for addressing the complex landscape of neurodegenerative and psychiatric conditions linked to memory impairments. However, the panoply of ethical implications arising from such a novel neurotechnology remains relatively unexplored by the neuroethics literature. This study examines and contrasts the potential ethical implications of memory modification treatment via implantable neurotechnologies. The study contends that undesired side effects resulting from memory modulation can lead to significant identity harms, disrupting the coherence of self-narratives and impinging on our authenticity. To evince the practical impact of this moral argument, the study conducts a practical ethical assessment of how employing implantable neurotechnologies to modulate memory may jeopardize (i) our moral responsiveness to events and core system of values and (ii) the emotional component associated with the altered memory. From a first-person standpoint, changes to the way we reasonably feel and react to past events and future intentions may be deemed ethically problematic as these profound changes can yield significant moral disruptions and negatively impact our personal lives and interpersonal relationships. In addition, the study discusses further ethical conundrums from a third-person perspective as these disruptions can inhibit social activism against structural injustices, thereby hindering societal progress. Thus, taking into account this societal dimension is paramount when evaluating the ethical permissibility of memory modification procedures.
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Chau SC, Chong PS, Jin H, Tsui KC, Khairuddin S, Tse ACK, Lew SY, Tipoe GL, Lee CW, Fung ML, Wong KH, Lim LW. Hericium erinaceus Promotes Anti-Inflammatory Effects and Regulation of Metabolites in an Animal Model of Cerebellar Ataxia. Int J Mol Sci 2023; 24:6089. [PMID: 37047062 PMCID: PMC10094689 DOI: 10.3390/ijms24076089] [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: 03/01/2023] [Revised: 03/18/2023] [Accepted: 03/20/2023] [Indexed: 04/14/2023] Open
Abstract
Cerebellar ataxia is a neurodegenerative disorder with no definitive treatment. Although previous study demonstrated the neuroprotective effects of Hericium erinaceus (H.E.), the mechanisms of H.E. treatment on the neuroinflammatory response, neurotransmission, and related metabolites remain largely unknown. We demonstrated that 3-AP rats treated with 25 mg/kg H.E. extracts had improved motor coordination and balance in the accelerated rotarod and rod tests. We showed that the H.E. treatment upregulated the expression of Tgfb1, Tgfb2, and Smad3 genes to levels comparable to those in the non-3-AP control group. Interestingly, we also observed a significant correlation between Tgfb2 gene expression and rod test performance in the 3-AP saline group, but not in the non-3-AP control or H.E.+3-AP groups, indicating a relationship between Tgfb2 gene expression and motor balance in the 3-AP rat model. Additionally, we also found that the H.E. treatment increased mitochondrial COX-IV protein expression and normalized dopamine-serotonin neurotransmission and metabolite levels in the cerebellum of the H.E.+3-AP group compared to the 3-AP saline group. In conclusion, our findings suggest that the H.E. treatment improved motor function in the 3-AP rat model, which was potentially mediated through neuroprotective mechanisms involving TGFB2-Smad3 signaling via normalization of neurotransmission and metabolic pathways.
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Affiliation(s)
- Sze Chun Chau
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Pit Shan Chong
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Hongkai Jin
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Ka Chun Tsui
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Sharafuddin Khairuddin
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Anna Chung Kwan Tse
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Sze Yuen Lew
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- Department of Anatomy, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - George Lim Tipoe
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Chi Wai Lee
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Man-Lung Fung
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Kah Hui Wong
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- Department of Anatomy, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Lee Wei Lim
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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Poon CH, Liu Y, Pak S, Zhao RC, Aquili L, Tipoe GL, Leung GKK, Chan YS, Yang S, Fung ML, Wu EX, Lim LW. Prelimbic Cortical Stimulation with L-methionine Enhances Cognition through Hippocampal DNA Methylation and Neuroplasticity Mechanisms. Aging Dis 2023; 14:112-135. [PMID: 36818556 PMCID: PMC9937711 DOI: 10.14336/ad.2022.0706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 07/06/2022] [Indexed: 11/18/2022] Open
Abstract
Declining global DNA methylation and cognitive impairment are reported to occur in the normal aging process. It is not known if DNA methylation plays a role in the efficacy of memory-enhancing therapies. In this study, aged animals were administered prelimbic cortical deep brain stimulation (PrL DBS) and/or L-methionine (MET) treatment. We found that PrL DBS and MET (MET-PrL DBS) co-administration resulted in hippocampal-dependent spatial memory enhancements in aged animals. Molecular data suggested MET-PrL DBS induced DNA methyltransferase DNMT3a-dependent methylation, robust synergistic upregulation of neuroplasticity-related genes, and simultaneous inhibition of the memory-suppressing gene calcineurin in the hippocampus. We further found that MET-PrL DBS also activated the PKA-CaMKIIα-BDNF pathway, increased hippocampal neurogenesis, and enhanced dopaminergic and serotonergic neurotransmission. We next inhibited the activity of DNA methyltransferase (DNMT) by RG108 infusion in the hippocampus of young animals to establish a causal relationship between DNMT activity and the effects of PrL DBS. Hippocampal DNMT inhibition in young animals was sufficient to recapitulate the behavioral deficits observed in aged animals and abolished the memory-enhancing and molecular effects of PrL DBS. Our findings implicate hippocampal DNMT as a therapeutic target for PrL DBS and pave way for the potential use of non-invasive neuromodulation modalities against dementia.
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Affiliation(s)
- Chi Him Poon
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Yanzhi Liu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Sojeong Pak
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong, China.
| | | | - Luca Aquili
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.,College of Science, Health, Engineering and Education, Discipline of Psychology, Murdoch University, Perth, Australia.
| | - George Lim Tipoe
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Gilberto Ka-Kit Leung
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Ying-Shing Chan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Sungchil Yang
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong, China.
| | - Man-Lung Fung
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Ed Xuekui Wu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China.
| | - Lee Wei Lim
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.,Correspondence should be addressed to: Dr. Lee Wei LIM, Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China. .
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The Monkey Head Mushroom and Memory Enhancement in Alzheimer’s Disease. Cells 2022; 11:cells11152284. [PMID: 35892581 PMCID: PMC9331832 DOI: 10.3390/cells11152284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 07/15/2022] [Accepted: 07/19/2022] [Indexed: 02/07/2023] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder, and no effective treatments are available to treat this disorder. Therefore, researchers have been investigating Hericium erinaceus, or the monkey head mushroom, an edible medicinal mushroom, as a possible treatment for AD. In this narrative review, we evaluated six preclinical and three clinical studies of the therapeutic effects of Hericium erinaceus on AD. Preclinical trials have successfully demonstrated that extracts and bioactive compounds of Hericium erinaceus have potential beneficial effects in ameliorating cognitive functioning and behavioral deficits in animal models of AD. A limited number of clinical studies have been conducted and several clinical trials are ongoing, which have thus far shown analogous outcomes to the preclinical studies. Nonetheless, future research on Hericium erinaceus needs to focus on elucidating the specific neuroprotective mechanisms and the target sites in AD. Additionally, standardized treatment parameters and universal regulatory systems need to be established to further ensure treatment safety and efficacy. In conclusion, Hericium erinaceus has therapeutic potential and may facilitate memory enhancement in patients with AD.
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Yu WS, Aquili L, Wong KH, Lo ACY, Chan LLH, Chan YS, Lim LW. Transcorneal electrical stimulation enhances cognitive functions in aged and 5XFAD mouse models. Ann N Y Acad Sci 2022; 1515:249-265. [PMID: 35751874 DOI: 10.1111/nyas.14850] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Dementia is a major burden on global health for which there are no effective treatments. The use of noninvasive visual stimulation to ameliorate cognitive deficits is a novel concept that may be applicable for treating dementia. In this study, we investigated the effects of transcorneal electrical stimulation (TES) on memory enhancement using two mouse models, in aged mice and in the 5XFAD model of Alzheimer's disease. After 3 weeks of TES treatment, mice were subjected to Y-maze and Morris water maze tests to assess hippocampal-dependent learning and memory. Immunostaining of the hippocampus of 5XFAD mice was also performed to examine the effects of TES on amyloid plaque pathology. The results showed that TES improved the performance of both aged and 5XFAD mice in memory tests. TES also reduced hippocampal plaque deposition in male, but not female, 5XFAD mice. Moreover, TES significantly reversed the downregulated level of postsynaptic protein 95 in the hippocampus of male 5XFAD mice, suggesting the effects of TES involve a postsynaptic mechanism. Overall, these findings support further investigation of TES as a potential treatment for cognitive dysfunction and mechanistic studies of TES effects in other dementia models.
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Affiliation(s)
- Wing Shan Yu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Luca Aquili
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.,Discipline of Psychology, College of Science, Health, Engineering and Education, Murdoch University, Perth, Western Australia, Australia
| | - Kah Hui Wong
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.,Faculty of Medicine, Department of Anatomy, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Amy Cheuk Yin Lo
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Leanne Lai Hang Chan
- Department of Electrical Engineering, City University of Hong Kong, Hong Kong SAR, China
| | - Ying-Shing Chan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Lee Wei Lim
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
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Roy J, Wong KY, Aquili L, Uddin MS, Heng BC, Tipoe GL, Wong KH, Fung ML, Lim LW. Role of melatonin in Alzheimer's disease: From preclinical studies to novel melatonin-based therapies. Front Neuroendocrinol 2022; 65:100986. [PMID: 35167824 DOI: 10.1016/j.yfrne.2022.100986] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 01/21/2022] [Accepted: 02/07/2022] [Indexed: 12/11/2022]
Abstract
Melatonin and novel melatonin-based therapies such as melatonin-containing hybrid molecules, melatonin analogues, and melatonin derivatives have been investigated as potential therapeutics against Alzheimer's disease (AD) pathogenesis. In this review, we examine the developmental trends of melatonin therapies for AD from 1997 to 2021. We then highlight the neuroprotective mechanisms of melatonin therapy derived from preclinical studies. These mechanisms include the alleviation of amyloid-related burden, neurofibrillary tangle accumulation, oxidative stress, neuroinflammation, apoptosis, mitochondrial dysfunction, and impaired neuroplasticity and neurotransmission. We further illustrate the beneficial effects of melatonin on behavior in animal models of AD. Next, we discuss the clinical effects of melatonin on sleep, cognition, behavior, psychiatric symptoms, electroencephalography findings, and molecular biomarkers in patients with mild cognitive impairment and AD. We then explore the effectiveness of novel melatonin-based therapies. Lastly, we discuss the limitations of current melatonin therapies for AD and suggest two emerging research themes for future study.
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Affiliation(s)
- Jaydeep Roy
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Kan Yin Wong
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Luca Aquili
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China; College of Science, Health, Engineering and Education, Discipline of Psychology, Murdoch University, Perth, Australia
| | - Md Sahab Uddin
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Boon Chin Heng
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China; Peking University School of Stomatology, Beijing, China
| | - George Lim Tipoe
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Kah Hui Wong
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China; Department of Anatomy, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Man Lung Fung
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Lee Wei Lim
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
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Restoring vision using optogenetics without being blind to the risks. Graefes Arch Clin Exp Ophthalmol 2021; 260:41-45. [PMID: 34724112 PMCID: PMC8558540 DOI: 10.1007/s00417-021-05477-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/12/2021] [Accepted: 10/25/2021] [Indexed: 11/25/2022] Open
Abstract
Retinit is pigmentosa is an incurable degenerative disease that causes loss of light-sensitive cells in the retina and leads to severe vision impairment. The development of optogenetics has created great hype around its potential to treat retinitis pigmentosa by the introduction of light-sensitive proteins into other neural cells in the retina. The first-in-human studies of optogenetic treatment for this disease have recently been reported (NCT02556736 and NCT03326336). The treatment involves irreversible gene therapy and requires access to specially designed goggles to deliver light to the treated eye. These highly innovative and high-profile clinical trials raise numerous ethical issues that must be addressed during the early phases of research and clinical testing to ensure trial participants are treated fairly and can provide appropriate informed consent.
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Chan HJ, Yanshree, Roy J, Tipoe GL, Fung ML, Lim LW. Therapeutic Potential of Human Stem Cell Implantation in Alzheimer's Disease. Int J Mol Sci 2021; 22:10151. [PMID: 34576314 PMCID: PMC8471075 DOI: 10.3390/ijms221810151] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/14/2021] [Accepted: 09/15/2021] [Indexed: 12/27/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive debilitating neurodegenerative disease and the most common form of dementia in the older population. At present, there is no definitive effective treatment for AD. Therefore, researchers are now looking at stem cell therapy as a possible treatment for AD, but whether stem cells are safe and effective in humans is still not clear. In this narrative review, we discuss both preclinical studies and clinical trials on the therapeutic potential of human stem cells in AD. Preclinical studies have successfully differentiated stem cells into neurons in vitro, indicating the potential viability of stem cell therapy in neurodegenerative diseases. Preclinical studies have also shown that stem cell therapy is safe and effective in improving cognitive performance in animal models, as demonstrated in the Morris water maze test and novel object recognition test. Although few clinical trials have been completed and many trials are still in phase I and II, the initial results confirm the outcomes of the preclinical studies. However, limitations like rejection, tumorigenicity, and ethical issues are still barriers to the advancement of stem cell therapy. In conclusion, the use of stem cells in the treatment of AD shows promise in terms of effectiveness and safety.
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Affiliation(s)
| | | | | | | | | | - Lee Wei Lim
- School of Biomedical, Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China; (H.J.C.); (Y.); (J.R.); (G.L.T.); (M.-L.F.)
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