BRAIN-GUT DYSFUNCTION IN OBESE SUBJECTS AND EFFECTS OF LAPAROSCOPIC SLEEVE GASTRECTOMY ON GASTRIC PACE-MAKING ACTIVITY
Payam Gharibani*1, Alimujiang Maisiyiti1, Yan Dong1, Jiafei Cheng1, Jiande Chen1, Alisa Coker2
1The Johns Hopkins School of Medicine, Division of Gastroenterology and Hepatology, Baltimore, MD; 2The Johns Hopkins School of Medicine, Department of Surgery, Baltimore, MD
Background and Aims: Alterations in the microbiome brain-gut axis have been well documented in obesity; however, little is known whether the autonomic function that communicates between the brain and the gut is also altered, especially in response to food intake. While the laparoscopic sleeve gastrectomy (LSG) is the most common bariatric surgery performed for obesity, it is unclear whether LSG alters the autonomic functions and gastric pace-making activity. The aims of this study were therefore 1) to investigate alterations in autonomic and gastric functions in obesity and 2) to study the effects of LSG on these functions in obese patients.
Method: Twenty morbidly obese subjects (BMI > 35) participated in this study. The autonomic functions and gastric pace-making activities in the fasting and postprandial state before and 3 months after LSG were assessed via the spectral analysis of heart rate variability (HRV) derived from the ECG and the electrogastrogram (EGG), respectively, and compared with those from 39 healthy controls (HC).
Results: 1) Alterations in autonomic functions in obese: Spectral analysis of HRV showed a significant increase in sympathovagal balance (LF/HF) after food intake in HC (fed=3.58±2.53 vs. fast=2.41±1.83, p=0.02), which was completely absent in obese subjects both before and after LSG, suggesting an impaired gut-brain interaction. 2) Alterations in gastric pace-making function in obese: Compared with HC, obese subjects showed a reduced % of normal gastric slow-wave (GSW) in the fasting state (79.79±14.75 vs. 64.48±21.21; p=0.01) and altered gastric region-related postprandial responses in the power and percentage of normal GSW. 3) LSG did not alter autonomic functions. 4) LSG reduced the % of normal GSW in the antrum in the fasting state (86.64±14.47 vs. 80.73±18.39; p=0.02) but not in the postprandial state; LSG also reduced the frequency of the GSW in the antrum (2.76±0.53 Vs. 2.24±0.17, p=0.001). 5. As expected, the gastric accommodation was reduced significantly after LSG by -58.2% (p<0.001) in obese subjects. Meanwhile, although LSG caused no change in GERD symptoms, the gastroparesis cardinal symptom index score was increased by double fold, showing the impact of LSG on fullness/early satiety as well as bloating/distention following food consumption.
Conclusion: Obese subjects exhibit altered postprandial responses in both autonomic functions and gastric pace-making activity. LSG that removes a large portion of the stomach reduces the frequency and normality of pace-making activity in the antrum; however, the effects are noted only in the fasting state, suggesting preservation of antral pace-making activity in the postprandial state. The weight loss effect of LSG is associated with reduced gastric accommodation and postprandial dyspeptic symptoms.
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