Role of Gut Hormones in Acutely Ill Patients

Abstract

The nutritional status in patients in ITU appears to decline not only during their stay in ITU but long after discharge from ITU. The deterioration in nutritional status during and after ITU management is not fully understood. Re-establishing normal spontaneous feeding after critical illness is a vital component in the recuperative process. Gut released peptides, such as ghrelin and peptide YY (PYY) that regulate the initiation and termination of meals (Cummings et al. 2002, Batterham et al. 2002), could play a role in the altered eating behaviour patients. The aim of this study was to assess the pattern of ghrelin and PYY during the stay of ITU patients in hospital. 16 patients aged 60± 4.7yrs, BMI 28.1± 1.7kg/m2 (mean± SEM) admitted to ITU underwent fasting blood sample collections every second day throughout the first week on ITU and once a week thereafter until day 28 or discharge home. Changes in appetite, biochemical and anthropometric markers of nutritional status were recorded. Three fasting blood samples at least three days apart were collected from the 36 matched age and BMI healthy volunteers 54.3±2.9yrs, p=0.3 BMI 25.8±0.8kg/m2 P=0.2. As compared with healthy subjects, ITU patients exhibited a significantly lower level of ghrelin (day one 297±76.3 v. 919.8±88.3 pmol/l P<0.001) during their stay in ITU and afterwards with a trend to rise to the normal level during the last three weeks of stay. Conversely ITU patients showed a significantly higher level of PYY (day one 31.5±9.6 v. 11.2±1.6 pmol/l P<0.05) throught their stay in ITU with a downward trend to the normal level during the last three weeks of their stay however it did not reach the healthy subjects’ level. There was a negative correlation between percentage increase in ghrelin and percentage decrease in PYY (r=0.4 P>0.05). Column chromatography showed the ghrelin and PYY in the right place as standard and confirmed endogenous ghrelin/PYY like immumoreactivity. Our observations suggest that Ghrelin may be one mechanism involved in appetite regulation and PYY might be one mechanism involved in inhibiting appetite in these sick patients.