What are Macrophages(Stool)?

Intestinal macrophages constitute the largest pool of macrophages in the body and have emerged as crucial sentinels for pathogen recognition and elimination. The source and development of intestinal macrophages, as well as their distinct properties, have been well documented. Intestinal macrophages exert their functions in the maintenance of intestinal homeostasis by shaping host-microbiota symbiosis, managing gut inflammation, crosstalking with T cells, and facilitating wound repair. Recently, nutritional regulation of intestinal macrophages has attracted substantial attention and is becoming a promising approach to disease prevention and control. Understanding the mechanisms employed by intestinal macrophages in mediating intestinal immune homeostasis and inflammation, as well as the mode of action of dietary nutrients in the modulating functions of intestinal macrophages, represents an opportunity to prevent and control inflammatory bowel diseases.

The gastrointestinal tract mucosa is continually exposed to a high load of antigens, ranging from dietary proteins and commensal microbiota to clinically important pathogens, viruses, and toxins. A single layer of intestinal epithelial cells forms a barrier between the lamina propria and the luminal contents of the intestine. Intestinal macrophages that reside in the subepithelial lamina propria (LP) represent the most abundant mononuclear phagocytes in the body and have emerged as crucial sentinels for the maintenance of intestinal homeostasis. As the first phagocytic cells of the innate immune system, intestinal macrophages engulf and clear pathogens, cellular debris, and bacterial products, constantly maintaining a balance between immunity against foreign pathogens and tolerance to commensals. Nonetheless, the cellular and molecular mechanisms by which this critical balance is achieved remain relatively unknown. Due to the crucial role of macrophages in the initiation and development of intestinal immunity, therapeutically manipulating macrophages are becoming an attractive way for disease prevention and treatment. In this review, we focus our attention on intestinal macrophages, describing the recent insights into the role of intestinal macrophages in maintaining gut homeostasis and managing gut inflammation. Finally, we will discuss the nutritional modulation of intestinal macrophage function and the potential of nutritional strategies aimed at manipulating intestinal macrophages to ameliorate inflammatory bowel disorders.