High cholesterol leads to long-term scarring of the liver and immune cell dysfunction

The link between a high-fat, high-sugar diet and fatty liver has a long history, which can lead to life-threatening diseases

The lab study, published in Frontiers in Immunology, is the first to look at how different levels of cholesterol in high-fat and high-sugar diets affect the progression of fatty liver disease

Corresponding author Dr Ana Maretti-Mira said: "We found that you may have a diet high in fat and sugar, but when you add high cholesterol to it, it accelerates the process

High cholesterol can aggravate fatty liver

The researchers fed the mice high-fat, high-sugar foods that would cause a late-stage fatty liver disease similar to a human disease

The mice were divided into three groups and received different levels of food cholesterol

After 20 weeks, fat accumulation occurred in the livers of all three groups of mice, a benign feature of fatty liver disease, but the livers of the high-cholesterol group showed more severe lesions, increased inflammation and scar tissue

Over the next 10 weeks, three groups of mice consumed low cholesterol

The body's multi-purpose cells of first line of defense undergo destructive changes

Maretti-Mira and her colleagues also delve into changes in macrophages, which are important for innate immune responses and are the first line of the body's natural defenses

Macrophages are linked to fatty liver disease, but in a paradoxical way: They seem to help promote damage, but without them, the damage doesn't heal

The researchers used RNA sequencing to compare the expression

However, in the macrophages of the initial high-cholesterol group, the gene that causes scarring remains active

The advice for your diet is: everything should be balanced

The high-fat, high-sugar diet given to mice in the study bears an unfortunate resemblance to the typical Western diet of humans

Mareti-Mira said: "We have a lot of carbohydrates in our daily diet, such as sugary drinks, bread, rice and pasta

Still, she stresses that her team's findings don't suggest that people should completely reduce cholesterol

Instead, moderation is key

"Everything is a balance," Maretti-Mira said