Limiting calorie intake prevents asthma symptoms caused by inflammation

Researchers at the University School of Medicine experimented with mice and reported that low-calorie feeds can prevent asthma symptoms in mice, even if the feed contains fat and sugar. The researchers also said they found that obesity caused by high-calorie diets caused inflammation in the lungs of the mice, which caused asthma symptoms, and a drug that prevented inflammation could alleviate these symptoms.

In an experimental report published in the Science Report, the researchers said that their experimental results provide more evidence that there is a link between obesity, inflammation and asthma, and that anti-inflammatory drugs are characteristic asthma in the treatment of obesity in humans. It has value in terms of symptoms. Scientists and clinicians have known for decades that fat people are more likely to have certain types of asthma than normal weight, or asthma symptoms may worsen. According to the US Centers for Disease Control and Prevention, 38.8% of adults with asthma are obese, a much higher proportion than adults without asthma (26.8%). However, the biological mechanisms and risks behind obesity-related asthma symptoms remain unclear.

Dr. Vsevolod Polotsky, professor of pulmonary and intensive care medicine at Johns Hopkins University School of Medicine and senior author of the report, said: Previous studies have shown that high-fat or high-sugar ingredients in the diet that causes obesity contribute to inflammation of the lungs and cause Asthma. However, our study shows that obesity can lead to inflammation-related asthma symptoms regardless of diet, and limiting calorie intake by any means may prevent or treat asthma by reducing inflammation.

Asthma is a common chronic lung disease caused by inflammation of the lungs that causes airway narrowing, resulting in asthma, cough, shortness of breath and chest tightness.

Polotsky said his team conducts animal experiments to identify the link between obesity, asthma, diet and inflammation, and develop new treatment options, especially since traditional therapies such as steroid sprays do not work well for obese asthma patients.

In this study, the researchers fed normal male mice with one of four feeds: low-calorie feed; high-calorie feed per gram of calories and fat; higher fat per gram and added sugar High-calorie feed; and high-calorie, high-trans fat feed with added sugar. In addition, a single group of mice were fed a high-calorie diet, but their daily intake was limited, matching the caloric value of mice fed a low-calorie diet.

After eight weeks, mice fed any high-calorie diet without limiting their food intake gained at least 7 grams more than those fed low-calorie feed or high-calorie feed but limited in food intake. The researchers continued to assess the lung function of the mice and examined whether they developed asthma symptoms by measuring the narrowing of the lung airways when the rats inhaled different doses of methacholine, a drug that causes airway contraction. When inhaling a dose of 30 mg per milligram of methacholine, the airway contraction of mice fed a variety of high-calorie diets without limiting the amount of food was at least 6.3 times the baseline, while feeding low-calorie feeds or feeding high-calorie feeds and limiting The airway contraction of the rats in the food intake was 4.7 times the maximum. The results of these tests (similar to the tests used to screen or diagnose human asthma) showed that asthmatic symptoms and obesity were observed in mice fed high-calorie diets.

In a previous study, Polotsky and his team demonstrated an increase in IL-1 beta (interleukin) levels in mice fed a high-calorie diet for two weeks. The appearance of this protein indicates an inflamed condition in the mouse.

In the new experiment, the researchers first fed rats with eight weeks of high-fat diets to seek to further determine the link between obesity, inflammation, and asthma. Then, in the last two weeks, they injected a group of mice with a drug called anakinra every day to block the activity of IL-? protein and prevent inflammation by preventing it from reaching the target.

At the end of the eight weeks, when the airway responsiveness was measured using a 30 mg dose of methacholine per ml, the airway contraction of anakinra-injected obese mice was 2.9 times the baseline, lower than no injection. The drug was 5.1 times more than the obese mice.

The researchers said the results showed that preventing inflammation in mice seemed to prevent the airway from overreacting to asthma triggers and might restore normal lung responses in obese mice. Polotsky said: The drugs we use are commercially available and can be tested as potential therapies for obese asthma patients because their disease is resistant to standard therapies. Researchers say they need to copy the experiment to a female mouse to see how it works before continuing with clinical trials.