Background: Dyspeptic symptoms are frequently induced, or exacerbated, by fatty food ingestion. Excessive release of, and/or hypersensitivity to, cholecystokinin (CCK) may explain the exaggerated response to lipid in patients with functional dyspepsia (FD). Thus far, plasma CCK response has been evaluated. However, stimulation of CCK1 receptors on duodenal vagal afferents occurs in a paracrine manner, suggesting that mucosal CCK concentrations are relevant to quantify. Apolipoprotein A-IV stimulates mucosal CCK release.
Aim: To investigate the hypothesis that fat-induced release of CCK and apolipoprotein A-IV (apoA-IV) is enhanced in the duodenum of FD patients.
Patients and methods: Sixteen symptomatic FD patients and 10 healthy volunteers (HV) underwent duodenal perfusion with intralipid 20%, 2 kcal/min, for 60 min. Symptoms were scored and blood samples were collected every 15 min during lipid perfusion and 15 min after discontinuation when duodenal biopsies were taken. Plasma and mucosal concentrations of CCK and apoA-IV were quantified.
Results: Abdominal discomfort (P=0.001), nausea (P=0.05), and fullness (P=0.005) in response to duodenal lipid increased significantly only in FD patients. Following lipid infusion, the mean mucosal CCK concentration was lower in FD patients compared with HV (P<0.0001). Fasting concentrations and plasma response of CCK were comparable in FD patients and HV. Plasma apoA-IV response appeared to differ between patients and HV, whereas mucosal apoA-IV concentrations were similar.
Conclusion: Our results suggest excessive local release of CCK in response to duodenal lipid in FD. This likely causes exaggerated stimulation of duodenal vagal afferents, explaining dyspeptic symptom generation. The mechanisms underlying elevated mucosal CCK release warrant further investigation.
aDepartment of Gastroenterology and Hepatology, University Medical Centre Utrecht, Utrecht
bDepartment of Gastroenterology, Saint Antonius Hospital, Nieuwegein, The Netherlands
cMedical Department IV, Campus Innenstadt, LMU University Clinic Munich, Munich, Germany
dDiscipline of Medicine, Royal Adelaide Hospital, University of Adelaide, Adelaide, Australia
Correspondence to Ofke S. van Boxel, MD, PhD, Department of Gastroenterology and Hepatology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands Tel: +31 88 7551378; fax: +31 88 7555533; e-mail: firstname.lastname@example.org
Received June 27, 2013
Accepted September 12, 2013