Science: Obesity is really not to be taken lightly! The latest research shows that obesity reprograms immune cells and damages the eyes

A Canadian study published in the journal Science elucidates a new molecular mechanism
that may lead to age-related macular degeneration (AMD).

Research by the University of Montreal's Maisonneuve-Rosement Hospital shows that life stressors such as obesity reprogram immune system cells and cause damage
to the eyes as they age.

Przemyslaw (Mike) Sapieha, a professor of ophthalmology at the University of Montreal, said: "We wanted to know why some people with a genetic predisposition develop AMD and others do not
.
" His postdoctoral researcher, Dr.
Masayuki Hata, was also involved in the study
.

Sapieha explains: "Although scientists have put considerable effort into understanding the genes that cause AMD, variations and mutations in susceptibility genes only increase the risk of developing this disease, not cause it
.
"

"This observation suggests that we must better understand how other factors, such as environment and lifestyle, contribute to the development of
the disease.
"

AMD macular degeneration is the leading cause of irreversible blindness worldwide, affecting
approximately 196 million people by 2020.
It comes in two forms:

• dry macular degeneration, characterized by fat accumulation at the back of the eye and death of nerve cells within the eye,

• Wet macular degeneration, characterized by the most sensitive part of the tissues that produce vision, the macula – is the blood vessels
  that cause lesions.
  

Contact with pathogens

The immune system in the eyes of AMD patients is known to become dysfunctional and aggressive
.
Normally, immune cells keep eyes healthy, but contact with pathogens such as bacteria and viruses can make them go wrong
.

At the same time, immune cells are also activated when the body is exposed to stressors, such as excess fat in obesity, making overweight the number one non-genetic risk factor for AMD, second only to smoking
.

In the latest study, Sapieha and Hata used obesity as a model to accelerate and exaggerate the stress
the body experiences over a lifetime.
They found that transient obesity, or a history of obesity, led to persistent changes in the structure of DNA within immune cells, making them more susceptible to inflammatory molecules
.

"Our findings provide important information about the immune cell biology that causes AMD and will allow for the development of more targeted therapies in the future," Hata said
.

The researchers hope their findings will lead other scientists to expand their interest beyond obesity-related diseases to other diseases characterized by increased neuroinflammation, including Alzheimer's disease and multiple sclerosis
.