Normal regulation of elevated plasma ghrelin concentrations in dialysis patients

Chronic renal failure is often associated with malnutrition, and malnourished patients are subject to increased morbidity and mortality. Therefore plasma concentrations of the stomach-derived peptide hormone ghrelin, which has been shown to exert potent GH-releasing and appetite-stimulating effects, were determined and correlated with nutritional parameters.

Twenty-four patients (15 male, 9 female) undergoing hemodialysis (HD) were studied. In addition, six patients were studied before and one hour after ingestion of a meal and five were studied immediately before and at the end of the dialysis session.

Chronic renal insufficiency was associated with significantly elevated ghrelin levels (320.1 +/- 57 fmol/mL vs. 75.6 +/- 12.4 fmol/mL in controls; p < 0.007). Plasma ghrelin concentrations were also significantly higher in the 16 normal-weight patients than in the eight overweight or obese patients (399.6 +/- 76.3 fmol/mL vs. 161.1 +/- 41.3 fmol/mL; p < 0.03). Ingestion of food induced a decrease in five out of six patients tested (mean 242.3 +/- 66.5 fmol/mL vs. 186 +/- 30.7 fmol/mL; n.s.). HD also resulted in a significant decrease of elevated ghrelin concentrations: ghrelin was in the normal range at the end of HD in four of the five patients tested. Plasma ghrelin concentrations did not correlate with nutritional parameters except for cholinesterase which was negatively correlated to ghrelin.

Plasma ghrelin concentrations are elevated in HD. The fact that ghrelin concentrations are higher in normal-weight than in overweight or obese HD patients and suppressed after ingestion of a meal suggests that the regulation of ghrelin release is retained in HD patients, albeit shifted to a higher level.