title: Functional dyspepsia patients have lower mucosal cholecystokinin concentrations in response to duodenal lipid.
abstract: 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.
  
  
  OBJECTIVE
  To investigate the hypothesis that fat-induced release of CCK and apolipoprotein A-IV (apoA-IV) is enhanced in the duodenum of FD patients.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: 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.
authors.forename: Ofke S
authors.initials: OS
authors.lastname: van Boxel
authors.forename: José J M
authors.initials: JJ
authors.lastname: ter Linde
authors.forename: Jac
authors.initials: J
authors.lastname: Oors
authors.forename: Bärbel
authors.initials: B
authors.lastname: Otto
authors.forename: Bas L A M
authors.initials: BL
authors.lastname: Weusten
authors.forename: Christine
authors.initials: C
authors.lastname: Feinle-Bisset
authors.forename: André J P M
authors.initials: AJ
authors.lastname: Smout
authors.forename: Peter D
authors.initials: PD
authors.lastname: Siersema
mesh_terms: D000328:Adult; D001054:Apolipoproteins A / Q000378:metabolism; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D001706:Biopsy; D016022:Case-Control Studies; D002766:Cholecystokinin / Q000097:blood / Q000378:metabolism*; D015536:Down-Regulation; D004386:Duodenum / Q000378:metabolism*; D004415:Dyspepsia / Q000097:blood / Q000175:diagnosis* / Q000378:metabolism; D004655:Emulsions / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D010743:Phospholipids / Q000008:administration & dosage; D011237:Predictive Value of Tests; D013024:Soybean Oil / Q000008:administration & dosage; D013997:Time Factors
chemical_list: D001054:Apolipoproteins A; D015415:Biomarkers; D004655:Emulsions; D010743:Phospholipids; C022205:apolipoprotein A-IV; C545823:soybean oil, phospholipid emulsion; D013024:Soybean Oil; D002766:Cholecystokinin