Inflammatory bowel disease (IBD) is an intensively investigated disorder because the incidence of IBD is continuously increasing. The advance of biologics has improved the outcome of treatment in IBD patients, resulting in an increased number of IBD patients in remission. Interestingly, approximately 30% of the remitted IBD patients have irritable bowel syndrome (IBS)-like symptoms such as abdominal pain and/or diarrhoea, and their quality of life is lessened. It is also interesting that IBS and/or functional dyspepsia frequently occurs in subjects who have suffered from infectious colitis. In this context, much attention has been paid to the hypothesis that the gastrointestinal minimal inflammation remaining after colitis plays a pivotal role in the development of functional gastrointestinal disorders (FGIDs).

The gut microbiome is a topic to clarify the pathophysiology of various diseases such as FGIDs, non-alcoholic steatohepatitis (NASH), obesity, diabetes, or mental diseases. Indeed, the imbalance of the gut microbiome profile is significantly involved in the pathophysiology of those diseases although their responsible mechanisms have not yet been elucidated. Accumulating evidence has suggested that antibiotics, psychological stress, and an imbalanced diet cause not only an abnormal profile of the gut microbiome but also gastrointestinal minimal inflammation. Therefore, it is very likely that gastrointestinal minimal inflammation related to those factors plays a crucial role in the pathophysiology of FGIDs and metabolic diseases.

This Special Issue therefore aims to collect original research and review articles providing new insights into gastrointestinal minimal inflammation in the pathophysiology of FGIDs and liver metabolism, especially focusing on the gut microbiome and the gastrointestinal immune system.

Potential topics include but are not limited to the following:

• Investigation of interrelationships among gastrointestinal minimal inflammation, gut microbiome, gastrointestinal immune system, gastrointestinal function in FGIDs, and liver dysfunction
• Breakthroughs in the current understanding of gastrointestinal minimal inflammation caused by gut microbiome-associated factors including infection, antibiotics, probiotics, psychological stress, diet, and others in FGIDs and liver dysfunction
• Relationship between gastrointestinal minimal inflammation and active pathophysiological processes such as autophagy, ferroptosis, pyroptosis, and oxidative response
• The involvement of inflammasome in the pathogenesis of gastrointestinal minimal inflammation in FGIDs and metabolic liver dysfunction
• The role of the innate immune system in dysbiosis in the pathophysiology of FGIDs and liver metabolism
• Potential therapeutic strategies targeting gastrointestinal minimal inflammatory reactions
• Biomarkers for minimal inflammation in the gastrointestinal tract
• The role of the intestinal mucosal barrier in the pathogenesis of gastrointestinal minimal inflammation in FGIDs and liver metabolism