Duodenal lipid-induced symptom generation in gastroesophageal reflux disease: role of apolipoprotein A-IV and cholecystokinin.
BACKGROUND
Duodenal lipid intensifies the perception of esophageal acid perfusion. Recently, we showed that genes implicated in lipid absorption were upregulated in the duodenum of fasting gastro-esophageal reflux disease (GERD) patients. This suggests that chylomicron production and secretion may be enhanced and, consequently, the release of apolipoprotein A-IV (apoA-IV), a chylomicron-derived signaling protein. ApoA-IV may stimulate release of cholecystokinin (CCK), an activator of vagal afferents. This study evaluated putative involvement of abnormal apoA-IV and CCK responses to lipid in GERD.


METHODS
Ten GERD patients and 10 healthy volunteers (HV) underwent duodenal perfusion with Intralipid 20%, 2 kcal min(-1) , for 60 min. Symptoms were scored, blood samples collected every 15 min during lipid perfusion and 15 min after discontinuation when duodenal biopsies were taken. Plasma and mucosal concentrations of apoA-IV and CCK and transcript levels of 21 genes implicated in lipid absorption, differentially expressed under fasting conditions, were quantified.


RESULTS
Heartburn (P = 0.003), abdominal discomfort (P = 0.037) and nausea (P = 0.008) only increased significantly during lipid infusion in GERD patients. Following lipid infusion mean mucosal apoA-IV concentration was lower in GERD patients compared with HV (P = 0.023), whereas plasma concentration tended to be elevated (P = 0.068). Mean mucosal CCK concentration was also lower in GERD patients (P = 0.009). Two genes, HIBADH and JTB, were upregulated in GERD patients (P = 0.008 and P = 0.038, respectively).


CONCLUSIONS
Our results suggest excessive duodenal lipid-induced release of apoA-IV and CCK in GERD. We postulate that the resulting heightened activation of duodenal vagal afferents may underlie central sensitization, thereby increasing the perception of reflux events.
Department of Gastroenterology and Hepatology, University Medical Centre, Utrecht, the Netherlands. o.s.vanboxel@umcutrecht.nl
O S
OS
van Boxel
J J M
JJ
ter Linde
J
J
Oors
B
B
Otto
C
C
Feinle-Bisset
A J P M
AJ
Smout
P D
PD
Siersema
D000328:Adult; D000368:Aged; D001054:Apolipoproteins A / Q000096:biosynthesis*; D059333:Central Nervous System Sensitization / Q000502:physiology; D002766:Cholecystokinin / Q000096:biosynthesis*; D004386:Duodenum / Q000378:metabolism*; D004655:Emulsions / Q000494:pharmacology; D005260:Female; D005764:Gastroesophageal Reflux / Q000209:etiology / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D006801:Humans; D050356:Lipid Metabolism / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010743:Phospholipids / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D013024:Soybean Oil / Q000494:pharmacology
D001054:Apolipoproteins A; D004655:Emulsions; D010743:Phospholipids; C022205:apolipoprotein A-IV; C545823:soybean oil, phospholipid emulsion; D013024:Soybean Oil; D002766:Cholecystokinin