Influenza Infection Can Be Exacerbated by High Dietary Cholesterol

Influenza Infection Can Be Exacerbated by High Dietary Cholesterol ...

High levels of dietary cholesterol, according to a new research from the University of Illinois, make mice sicker when they infect with influenza. The first study to investigate cholesterol in the diet is the possibility of an exacerbation of a viral infection.

High-fat diets and increased blood cholesterol have previously linked increased susceptibility to infection and decreased immune responses. For example, obesity is a well-known risk factor for severe COVID and influenza. However, few studies have separated out the contribution of cholesterol in these infections, and none have delineated the effect of diet cholesterol.

We knew that high serum cholesterol levels might lead to a higher risk of sepsis in influenza infections, and that statins cholesterol-lowering drugs might improve survival during influenza pneumonia, SARS-CoV-2 infection, and sepsis. However, it wasn''t clear whether or how dietary cholesterol was involved, according to Allison Louie, the leading author of theJournal of Immunology, and a doctoral student from theNeuroscience Programat Illinois.

Cholesterol is essential in the body. Its key ingredient in our cells membranes, assists us in constructing hormones and vitamin D, and helps to maintain proper immune cell function. It is important that our bodies provide it for us, without having to use artificial foods to assess our cholesterol levels. This fact is, therefore, cholesterol levels do not affect circulating cholesterol levels, nor increase cardiovascular disease risk. In addition, cholesterol levels were removed from the Dietary Guidelines for Americans in 2015.

Although it comes to infectious disease in mice, a Louies study suggests that elevated cholesterol may be a major difference, even without increasing your dietary fat.

Louie, along with their co-authorsAndrew SteelmanandJoseph Tingling, fed mice a standard rodent chow or an identical diet with 2% cholesterol. After five weeks on the diets, mice were infected with a mouse-adapted influenza A virus. The research team also tracked serum cholesterol levels and immune responses and measured viral load in the lungs at various times during the infection.

The cholesterol-fed mice showed greater morbidity across four groups, according to Louie. They showed greater weight loss and sickness behavior.

There was a possibility that the high-cholesterol diet would boost viral load in the lungs, which isn''t what researchers predicted.

According to Tingling, a postdoctoral researcher at Illinois, the plaque assay did not show a significant difference in viral load in the two groups of mice. It''s very important to think about not only the infectious agent, but the host immune system.

mice fed a high-cholesterol diet were sicker because their immune systems went awry. Fat can have an immunosuppressive effect, which is detrimental during the course of an infection, according to the researchers. Instead, cholesterol increased the number of cytokine-producing immune cells in the lungs.

Extreme inflammation is causing the host to develop a so-called cytokine storm during severe illness. Several studies have shown that more cytokine-producing cells had infiltrated the lungs of mice fed cholesterol, which might have contributed to them being sicker. It''s a double-edged sword. You want to have an effective immune response, but excessive inflammation is causing a strain.

Despite the fact that mice had never consumed a high cholesterol diet, the effects of dietary cholesterol on influenza morbidity lasted long after they got sick. Using mice who received a high cholesterol regimen then gave them a normal treatment for five weeks. When these mice were exposed to influenza, they became sicker.

We were thinking this dietary component was a quite virtuous factor. It may, however, have a transient effect. Yet, we concluded that five weeks on a normal diet was inadequate time to fully reverse the harmful effects of cholesterol.

Even before they were infected with influenza, inflammatory changes in the lungs were discovered.

Adding to that, some changes in the immune function of the lungs were already observed before infection. It might be interesting to see precisely how dietary cholesterol increased inflammation prior to infection, according to the corresponding author. Steelman, an associate professor at the Department of Animal Sciences, the Neuroscience Program, and the Department of Nutritional Sciencesat Illinois.

Nevertheless, our findings suggest that dietary cholesterol increased morbidity in influenza-infected mice. This appeared to be the result of an aberrant immune response in the lungs rather than an effect of the virus itself. These findings demonstrate the need to consider the host factors to determine the outcome of the disease.

According to the authors of the June 2022 issue, Dietary cholesterol causes inflammation and increases morbidity in mice who have influenza A virus. NIFA Hatch funding, a National Multiple Sclerosis Society grant, and a Margin of Excellence Award from the Division of Nutritional Sciences at Illinois have helped the research.

The Department of Animal Sciences and the Division of Nutritional Sciences are located in the University of Illinois Urbana-Champaign, a municipality located in the United Illinois State.

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