Faecal Inflammatory Biomarkers and Gastrointestinal Symptoms after Bariatric Surgery: A Longitudinal Study.

BACKGROUND: Bariatric surgery induces various gastrointestinal (GI) modifications. We performed the first study longitudinally assessing the effect of bariatric surgery on faecal inflammatory biomarker levels and its relation with GI complaints. METHOD: Faecal calprotectin, lactoferrin, and calgranulin-C levels were determined in 41 patients (34 Roux-en-Y [RYGB], 7 sleeves) before and at 6-16 weeks, 6 months, and 1 year after surgery. Changes in biomarker levels and percentage of patients above reference value were determined. Gastrointestinal symptom rating scale (GSRS) was used to assess GI complaints at corresponding time points. The postoperative relation between GSRS score and biomarker levels above reference value was investigated. RESULTS: After RYGB, median calprotectin levels are significantly higher (>188, 104-415 µg/g) than before surgery (40, 19-78 µg/g; p < 0.001), and over 90% of patients have levels above reference value 1 year after surgery. Median lactoferrin was 0.4 (0.2-1.6) µg/g before, and >5.9 (1.8-13.6) µg/g after surgery (p < 0.001). Median calgranulin-C levels remained far below the reference value and were 0.13 (0.05-0.24) µg/g before and <0.23 (0.06-0.33) µg/g after surgery. Similar results were found after sleeve gastrectomy. No difference was seen in GSRS score for patients with calprotectin and lactoferrin levels above reference values. CONCLUSION: Faecal inflammatory biomarkers calprotectin and lactoferrin, but not calgranulin-C, rise above reference values shortly after bariatric surgery and remain elevated in the majority of patients. The discrepancy between calprotectin and calgranulin-C levels suggests no GI inflammation. Furthermore, patients after RYGB with biomarkers above the population reference value do not seem to have more GI complaints.

Gastrointestinal symptoms before and after laparoscopic Roux-en-Y gastric bypass: a longitudinal assessment.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) is an effective treatment for morbid obesity, but many patients have increased gastrointestinal symptoms. OBJECTIVES: To evaluate gastrointestinal symptoms and food intolerance before and after RYGB over time in a large cohort of morbidly obese patients. SETTING: A high-volume bariatric center of excellence. METHODS: A prospective cohort study was performed in patients who underwent RYGB between September 2014 and July 2015, with 2-year follow-up. Consecutive patients screened for bariatric surgery answered the Gastrointestinal Symptom Rating Scale (GSRS) and a food intolerance questionnaire before RYGB and 2 years after surgery. The prevalence of gastrointestinal symptoms before and after surgery and the association between patient characteristics and postoperative gastrointestinal symptoms were assessed. RESULTS: Follow-up was 86.2% (n = 168) for patients undergoing primary RYGB and 93.3% (n = 28) for revisional RYGB. The total mean GSRS score increased from 1.69 to 2.31 after surgery (P < .001), as did 13 of 16 of the individual scores. Preoperative GSRS score is associated with postoperative symptom severity (B = .343, P < .001). Food intolerance was present in 16.1% of patients before primary RYGB, increasing to 69.6% after surgery (P < .001). Patients who underwent revisional RYGB had a symptom severity and prevalence of food intolerance comparable with that among patients with primary RYGB, even though they had more symptoms before revisional surgery. CONCLUSIONS: Two years after surgery, patients who underwent primary RYGB have increased gastrointestinal symptoms and food intolerance compared with the preoperative state. It is important that clinicians are aware of this and inform patients before surgery.

Fecal Calprotectin, Elastase, and Alpha-1-Antitrypsin Levels After Roux-en-Y Gastric Bypass; Calprotectin Is Significantly Elevated in the Majority of Patients.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) causes several alterations in gastrointestinal function. We hypothesized that levels of three commonly used fecal tests change after RYGB. METHODS: Fecal levels of calprotectin, elastase, and alpha-1-antitrypsin were determined in 122 patients without signs of gastrointestinal disease 1 to 2 years after RYGB. Medians, distribution of values, and the percentage of patients with levels above or below reference values were determined. RESULTS: Median fecal calprotectin level was 163.5 (<30-1587) µg/g; in 87 % of patients, it was above the reference value (<50 µg/g). Median fecal elastase level was 444 (<15-647) µg/g; 13 % was below the reference value (>200 µg/g). Median fecal alpha-1-antitrypsin level was 0.51 (<0.20-2.20) mg/g, comparable to the reference values. CONCLUSIONS: Fecal calprotectin levels are significantly higher than the reference value in most patients after RYGB. Fecal elastase is significantly lower. This might indicate that the validity of fecal calprotectin testing is impaired after RYGB and the specificity for fecal elastase is decreased. Clinical awareness of altered fecal markers after RYGB is essential to prevent unnecessary diagnostic tests, such as colonoscopy. Fecal alpha-1-antitrypsin is not influenced by RYGB.