Eye stimulation promises ‘remarkable’ treatment for depression and dementia

According to new research, electrical stimulation of the surface of the eye can alleviate depression-like symptoms and improve cognitive function in animal models.

Researchers discover noninvasive eye stimulation for depression and dementia.

Scientists have found that electrical stimulation of the surface of the eye can alleviate depression-like symptoms and improve cognitive function in animal models. These important findings from a joint research team of LKS Faculty of Medicine, University of Hong Kong (HKUMed) and City University of Hong Kong (CityU) were recently published in brain stimulation and the Annals of the New York Academy of Sciences.

Background

Major depression is the most common serious psychiatric disorder in the world. Recently, the World Health Organization (WHO) reported that the COVID-19 pandemic has triggered a massive increase in the number of people suffering from depression and anxiety. About 25% of patients do not respond adequately to currently available treatments.

In 2015, Dr. Lim Lee Wei, assistant professor at the School of Biomedical Sciences, HKUMed, and former researcher Lee Kuan Yew in Singapore, reported that deep brain stimulation of the prefrontal cortex in animal brains could alleviate depressive symptoms. and improve memory function. These therapeutic effects have been attributed to the growth of brain cells in the hippocampus, a region of the brain known to be involved in learning and memory functions. However, this technique, also known as deep brain stimulation, is invasive and requires surgery to implant electrodes inside the brain, which can lead to significant side effects such as infections and other complications. postoperative.

Noninvasive eye stimulation for depression and dementia

A joint research team from LKS Faculty of Medicine, University of Hong Kong (HKUMed) and City University of Hong Kong (CityU) has found that electrical stimulation of the surface of the eye can alleviate depression-like symptoms and improve cognitive function in animals. models. Members of the research team include (from left to right): Professor Chan Ying-shing, Dexter HC Man Family Professor of Medical Sciences, Professor of the School of Biomedical Sciences, Associate Dean (Development and Infrastructure), HKUMed and the Director of the Neuroscience Research Center, HKU; Dr. Leanne Chan Lai-hang, associate professor in the Department of Electrical Engineering, CityU; Yu Wing-shan, PhD student, School of Biomedical Sciences, HKUMed and Dr. Lim Lee Wei, Assistant Professor, School of Biomedical Sciences, HKUMed.

Search Results and Meaning

A team of researchers from Hong Kong has been looking for alternative ways to treat neuropsychiatric illnesses. They found that noninvasive stimulation of the corneal surface of the eye (known as transcorneal electrical stimulation, or TES) that activates brain pathways, resulted in remarkable antidepressant effects and reduced stress hormones in an animal model. of depression. Moreover, this technique also induces the expression of genes involved in the development and growth of brain cells in the hippocampus. This team of researchers is led by Dr. Lim Lee Wei; Dr. Leanne Chan Lai-hang, associate professor in the Department of Electrical Engineering, CityU; Professor Chan Ying-shing, Dexter HC Man Family Professor of Medical Sciences, Professor in the School of Biomedical Sciences, Associate Dean (Development and Infrastructure), HKUMed and Director of the Center for Neuroscience Research, HKU.

In related experiments, doctoral student Yu Wing-shan and other research members from the School of Biomedical Sciences, HKUMed, investigated whether this approach could be used to treat Alzheimer’s disease, a common type of dementia with no definitive cure. They found that this noninvasive stimulation in mice significantly improved memory performance and reduced beta-amyloid deposits in the hippocampus, which is one of the hallmarks of Alzheimer’s disease.

Dr. Leanne Chan Lai-hang, an expert in electrical stimulation of visual and non-visual brain targets, described the research: “Transcorneal electrical stimulation is a non-invasive method originally developed to treat eye disease, and it would be a major breakthrough. scientific breakthrough if it could be applied to treat neuropsychiatric diseases.

“These research results pave the way for new therapeutic opportunities to develop a new treatment for patients suffering from treatment-resistant depression and dementia. Nevertheless, clinical trials need to be conducted to validate the efficacy and safety,” Professor Chan Ying-shing remarked.

About the research team

The research was led by Dr. Lim Lee Wei, Assistant Professor in the School of Biomedical Sciences, HKUMed and former Lee Kuan Yew Research Fellow in Singapore; Dr. Leanne Chan Lai-hang, associate professor in the Department of Electrical Engineering, CityU; Professor Chan Ying-shing, Dexter HC Man Family Professor of Medical Sciences, Professor in the School of Biomedical Sciences, Associate Dean (Development and Infrastructure), HKUMed and Director of Center for Neuroscience Research, HKU; and conducted at HKU’s Neuromodulation Lab in collaboration with CityU at the Neural Interface Research Lab. Yu Wing-shan was the lead researcher. She is the recipient of a prestigious Hong Kong PhD scholarship, awarded by the Hong Kong Research Grants Council.

Thanks

This scientific work was supported by the General Research Fund of the Hong Kong Research Grants Council (No. 17119420 and No. 11208218), the Fund for Basic Research (No. 201811159133 and No. 201910159163) and for Research Translational and Applied, No. 201910160010); and the CityU Strategic Research Fund (#7005632).

References:

“Antidepressant-Like Effects of Transcorneal Electrical Stimulation in Rat Models” by Wing Shan Yu, Anna Chung-Kwan Tse, Li Guan, Jennifer Lok Yu Chiu, Shawn Zheng Kai Tan, Sharafuddin Khairuddin, Stephen Kugbere Agadagba, Amy Cheuk Yin Lo, Man-Lung Fung, Ying-Shing Chan, Leanne Lai Hang Chan and Lee Wei Lim, May 27, 2022, brain stimulation.
DOI: 10.1016/j.brs.2022.05.018

“Transcorneal Electrical Stimulation Enhances Cognitive Function in Aged and 5XFAD Mouse Models” by Wing Shan Yu, Luca Aquili, Kah Hui Wong, Amy Cheuk Yin Lo, Leanne Lai Hang Chan, Ying-Shing Chan, and Lee Wei Lim, 25 June 2022, New York Academy of Sciences.
DOI: 10.1111/nyas.14850

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