Macrophage-related diseases of the gut: a pathologist's perspective

Area of Science:

• Gastrointestinal immunology
• Innate immunity
• Macrophage biology

Background:

• Resident macrophages in the gastrointestinal tract form the largest population in the human body.
• Located in the subepithelial lamina propria, they provide first-line defense against luminal bacteria and antigens.
• In non-inflamed states, they perform microbial phagocytosis without inflammation, but are recruited during epithelial breaches.

Purpose of the Study:

• To review diseases mediated by or affecting resident gut macrophages.
• To highlight the role of these macrophages in both homeostatic and pathological conditions within the gastrointestinal tract.

Main Methods:

• Literature review of diseases involving gastrointestinal macrophages.
• Analysis of macrophage accumulation and function in pathological contexts.

Main Results:

• Gut macrophages are typically inconspicuous in normal mucosa but accumulate in pathological conditions.
• Their accumulation can be due to exogenous particulate material, endogenous substances, or increased numbers.
• Diseases reviewed are those where macrophages are either the cause or affected by the pathology.

Conclusions:

• Resident gut macrophages play a critical role in gastrointestinal health and disease.
• Understanding their involvement is crucial for diagnosing and treating various gut pathologies.
• Further research into macrophage-mediated diseases can lead to novel therapeutic strategies.