title: Cholecystokinin and leptin: their influence upon the eating behaviour and nutrient intake of dialysis patients.
abstract: BACKGROUND
  We have used serial visual analogue scores to demonstrate disturbances of the appetite profile in dialysis patients. This is potentially important as dialysis patients are prone to malnutrition yet have a lower nutrient intake than controls. Appetite disturbance may be influenced by accumulation of appetite inhibitors such as leptin and cholecystokinin (CCK) in dialysis patients.
  
  
  METHODS
  Fasting blood samples were drawn from 43 controls, 50 haemodialysis (HD) and 39 peritoneal dialysis (PD) patients to measure leptin and CCK. Hunger and fullness scores were derived from profiles compiled using hourly visual analogue scores. Nutrient intake was derived from 3 day dietary records.
  
  
  RESULTS
  Fasting CCK was elevated for PD (6.73 +/- 4.42 ng/l vs control 4.99 +/- 2.23 ng/l, P < 0.05; vs HD 4.43 +/- 2.15 ng/l, P < 0.01). Fasting CCK correlated with the variability of the hunger (r = 0.426, P = 0.01) and fullness (r = 0.52, P = 0.002) scores for PD. There was a notable relationship with the increase in fullness after lunch for PD (r = 0.455, P = 0.006). When well nourished PD patients were compared with their malnourished counterparts, CCK was higher in the malnourished group (P = 0.004). Leptin levels were higher for the dialysis patients than controls (HD and PD, P < 0.001) with pronounced hyperleptinaemia evident in some PD patients. Control leptin levels demonstrated correlation with fullness scores (e.g. peak fullness, r = 0.45, P = 0.007) but the dialysis patients did not. PD nutrient intake (energy and protein intake, r = -0.56, P < 0.0001) demonstrated significant negative correlation with leptin.
  
  
  CONCLUSIONS
  Increased CCK levels appear to influence fullness and hunger perception in PD patients and thus may contribute to malnutrition. Leptin does not appear to affect perceived appetite in dialysis patients but it may influence nutrient intake in PD patients via central feeding centres.
authors.affiliation: Renal Unit, Leeds General Infirmary, Great George Street, Leeds LS1 3EX, England, UK. mark.wright@leedsth.nhs.uk
authors.forename: Mark
authors.initials: M
authors.lastname: Wright
authors.forename: Graham
authors.initials: G
authors.lastname: Woodrow
authors.forename: Siobahn
authors.initials: S
authors.lastname: O'Brien
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Armstrong
authors.forename: Neil
authors.initials: N
authors.lastname: King
authors.forename: Louise
authors.initials: L
authors.lastname: Dye
authors.forename: John
authors.initials: J
authors.lastname: Blundell
authors.forename: Aleck
authors.initials: A
authors.lastname: Brownjohn
authors.forename: John
authors.initials: J
authors.lastname: Turney
mesh_terms: D000328:Adult; D000368:Aged; D001066:Appetite / Q000502:physiology; D001069:Appetite Regulation / Q000502:physiology*; D002766:Cholecystokinin / Q000502:physiology*; D003956:Dialysis; D015930:Diet Records; D004435:Eating / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D006801:Humans; D006815:Hunger / Q000502:physiology; D007676:Kidney Failure, Chronic / Q000503:physiopathology / Q000628:therapy; D020738:Leptin / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D012527:Satiation / Q000502:physiology
chemical_list: D020738:Leptin; D002766:Cholecystokinin