- Researchers studied how obesity affects the risk of age-related macular degeneration (AMD) in mouse models.
- They found that a history of obesity increased the risk of developing AMD, even though the mice lost weight and were no longer obese.
- More research is needed to see if these results translate to humans.
Age-related macular degeneration (AMD) is a
After smoking, obesity is the most important
Although there is a lot of research on genetic risk factors for AMD, there is little research on how environment and lifestyle influence disease risk.
Further research into how life and environmental factors affect AMD could explain why some people with genes associated with AMD never develop the disease. It can also inform treatment and prevention strategies.
Recently, researchers investigated how changes in body fat affect the risk of developing AMD in mice.
The study suggests that diet-induced obesity early in life alters the immune system […] Who can then [increase risk for] “AMD,” said Dr. Radwan Ajlan, an ophthalmologist with the University of Kansas Health System, who was not involved in the study. Medical news today.
The study appears in the journal Science.
What the researchers did
For the study, the researchers fed male rats a high-fat diet for 11 weeks to induce obesity. Then they put the mice on a regular diet for 9 weeks to reduce their weight. Control mice received a regular diet over the same 20-week period.
The researchers noted that after 11 weeks, the mice on the high-fat diet gained three times as much weight as the mice on a normal diet. However, after 6 weeks of a normal diet, their weight decreased to match that of the control mice.
They noted that metabolic measures such as insulin and glucose tolerance also matched those of the control mice at the end of the 20-week study period.
After the 20-week dietary study period, the researchers induced choroidal neovascularization (CNV) in the mice. CNV describes the growth of new blood vessels in the eye and is a major cause of vision loss. It is also present in more than 80% of cases of AMD.
Two weeks later, the researchers then measured the level of CNV in the two groups of mice.
They found that mice fed a high-fat diet followed by a normal diet had 40% more copy number variations than those fed exclusively a normal diet.
Then the researchers ran tests on the fat tissue of the mice. Although measurements of metabolism in previously obese mice matched those in mice with no history of obesity, they found that their adipose tissue retained characteristics that increase the risk of AMD.
“This study indicates that excess body fat causes changes in hormonal and cellular signaling in the rest of the body,” said Dr. Benjamin Burt, MD, an ophthalmologist at Memorial Care Orange Coast Medical Center in Fountain Valley, California. dtm.
In particular, the researchers hypothesize that an increase in waist circumference, that is, an increase in adipose tissue in the abdomen, increases these effects. In this study, they hypothesize that an increase in adipose tissue results in permanent changes in the way adipose tissue sends signals to other parts of the body. body, even after losing weight.
Obesity and macular degeneration
When asked whether obesity is related to AMD via mechanisms other than those in the study, Dr. Howard R. Krause, a neurologist and ophthalmologist and director of the Eye, Ear, and Cranial Center at the Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, said, California dtm:
There may be dietary factors involved [those with obesity], with a consequent excess of toxic substances or deficiency of essential nutrients, which have a direct effect on the retina independently of immune pathways. It is known that nutrition can affect macular degeneration.
Because obesity may be related to diet, these patients may not be consuming the nutrients needed to help slow the progression of macular degeneration. He noted that obesity may also be linked to other metabolic conditions such as diabetes and high blood pressure, which may also increase the risk of other retinal diseases.
Dr Burt noted that because the study was conducted on a mouse model, it remains to be seen if the results translate to humans. He also noted that the mice studied did not have AMD.
These mice placed a laser on their retinas to cause a type of damage similar to that caused by macular degeneration. However, the damage caused by the laser […] It is a different type of trauma to the retina and may not behave in the same way as macular degeneration.”
In conclusion, animal studies with more accurate models of AMD are needed along with human studies to see to what extent these findings apply to humans.
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