Macular degeneration is a progressive eye disease that affects the central part of the retina called the macula. It leads to loss of central vision, making it difficult to read, drive and recognize faces.
A new study from Canada published in a prestigious journal chemistryshed light on the potential molecular causes of age-related macular degeneration (AMD).
A study conducted at the Hôpital Maisonneuve-Rosemont in Montreal reveals that everyday life stressors, such as obesity, can alter the immune system and harm the eyes as we age.
“We wanted to know why some people with a genetic predisposition develop AMD while others are not affected,” said Przemyslaw (Mike) Sapieha, professor of ophthalmology at the University of Montreal. says.
“Although considerable effort has been made to understand the genes that cause AMD, mutations and mutations in susceptibility genes only increase the risk of developing the disease, they do not cause it,” Sapieha said. explained Mr.
“This observation suggests that we need to better understand how other factors, such as environment and lifestyle, contribute to disease development.
AMD is the leading cause of irreversible blindness worldwide, affecting approximately 196 million people in 2020. AMD has two forms of him.
- Dry AMD is characterized by the accumulation of fatty deposits behind the eyes and the death of nerve cells in the eye.
- Exudative AMD is characterized by diseased blood vessels that occur in the most sensitive part of the vision-producing tissue called the macula.
contact with pathogens
It is already known that the immune system in the eyes of people with AMD becomes dysregulated and aggressive.Immune cells normally keep the eyes healthy, but contact with pathogens such as bacteria and viruses can damage the eyes. function may be impaired.
At the same time, immune cells are also activated when the body is exposed to stressors such as excess fat from obesity, making obesity the number one non-genetic risk factor for developing AMD after smoking.
In their study, Sapieha and Hatha used obesity as a model to accelerate and exaggerate the stressors experienced by the body throughout life.
They found that transient obesity or a history of obesity led to lasting changes.[{” attribute=””>DNA architecture within immune cells, making them more susceptible to producing inflammatory molecules.
“Our findings provide important information about the biology of the immune cells that cause AMD and will allow for the development of more tailored treatments in the future,” said Hata, now an ophthalmology professor at Kyoto University, in Japan.
The researchers hope their discovery will lead other scientists to broaden their interest beyond obesity-related diseases to other diseases characterized by increased neuroinflammation, including Alzheimer’s disease and multiple sclerosis.
Reference: “Past history of obesity triggers persistent epigenetic changes in innate immunity and exacerbates neuroinflammation” by Masayuki Hata, Elisabeth M. M. A. Andriessen, Maki Hata, Roberto Diaz-Marin, Frédérik Fournier, Sergio Crespo-Garcia, Guillaume Blot, Rachel Juneau, Frédérique Pilon, Agnieszka Dejda, Vera Guber, Emilie Heckel, Caroline Daneault, Virginie Calderon, Christine Des Rosiers, Heather J. Melichar, Thomas Langmann, Jean-Sebastien Joyal, Ariel M. Wilson and Przemyslaw Sapieha, 5 January 2023, Science.
DOI: 10.1126/science.abj8894
