Micro-inflammation in functional dyspepsia: A systematic review and meta-analysis.

Area of Science:

• Gastroenterology
• Immunology
• Pathophysiology

Background:

• Functional dyspepsia (FD) is a common gastrointestinal disorder with unclear causes.
• While micro-inflammation is suspected, previous studies on immune activation in FD have yielded inconsistent results.

Purpose of the Study:

• To systematically review and meta-analyze immune cell counts and cytokine levels in individuals with FD compared to healthy controls.
• To investigate the role of immune activation in the pathogenesis of functional dyspepsia.

Main Methods:

• A systematic literature search was conducted across PubMed, Embase, and the Cochrane library.
• Data on immunologic cell counts and cytokine levels were extracted and compared using standard mean differences (SMD).
• Thirty-seven studies were included in the meta-analysis.

Main Results:

• Individuals with FD showed significantly increased mast cell and eosinophil counts in both the stomach and duodenum compared to controls.
• Elevated duodenal eosinophil counts were noted in both post-prandial distress syndrome and epigastric pain syndrome subtypes of FD.
• No significant differences were found in mucosal lymphocytes, enterochromaffin cells, neutrophils, or peripheral IL-6 and IL-10 levels.

Conclusions:

• Micro-inflammation, characterized by increased mast cells and eosinophils in the gastric and duodenal mucosa, is a significant feature in the pathogenesis of functional dyspepsia.
• These findings highlight local immune cell infiltration as a critical factor in FD development.