Serum cholinesterase activity is elevated in female diarrhea-predominant irritable bowel syndrome patients compared to matched controls

Background: Micro-inflammation is involved in the pathogenesis of irritable bowel syndrome (IBS). The parasympathetic nervous system, via acetylcholine (ACh), and its hydrolytic enzymes, plays a role in regulating inflammation. Increased serum cholinesterase activity, named cholinergic Status (CS), is associated with decreased inflammatory inhibition (ie, pro-inflammation). We assessed the association between IBS diarrhea-predominant (IBS-D) symptoms, CS, and inflammatory biomarkers. Methods: Women with IBS-D were prospectively recruited. Serum acetylcholinesterase (AChE), CS, and high-sensitivity C-reactive protein (hs-CRP) levels were analyzed and fecal calprotectin (FC) in a subgroup of patients. The control group included women attending routine health checkups (matched by age and BMI). Key Results: Ninety-four women with IBS-D were compared to matched controls (1:1). Serum CS, AChE, and the AChE/butyrylcholinesterase (BChE) ratios were significantly increased in the IBS-D group compared to matched controls (P = 0.018, P = 0.001, and P = 0.004, respectively). Using a multiple logistic regression model, IBS-D was almost twice as likely in women with high CS compared to women with low CS (adjusted OR=1.84 (95% CI: 1.01-3.33), P = 0.045). Furthermore, IBS-D patients with higher hs-CRP levels demonstrated lower CS and BChE activity and elevated AChE and AChE/BChE ratios compared to patients with lower hs-CRP levels (P = 0.026, P = 0.036, P = 0.002; and P = 0.0007, respectively). CS was not correlated with the IBS symptoms score. Conclusions and Inferences: This is the first study to explore the potential role of serum CS in IBS-D. The findings emphasize the possible role of the autonomic nervous system and its anti-inflammatory properties in IBS.