Ghrelin levels and changes in eating behaviour in the early stages of obesity-related chronic kidney disease

Background. Endocrine imbalance leading to impaired glomerular renal function is poorly understood. The role of the orexigenic hormone ghrelin in the development of renal dysfunction remains incompletely clarified. The purpose was to study ghrelin levels, their relation to the metabolic parameters, and changes in eating behaviour characteristics in the early stages of obesity-related chronic kidney disease (CKD). Materials and methods. 300 patients with CKD were examined and divided into 4 groups: the first group consisted of 70 people with the first stage CKD and normal body weight, the second group included 72 patients with the second stage CKD and normal body weight; the third group consisted of 70 people with the first stage CKD and obesity, and the fourth group included 88 patients with the second stage CKD and obesity. The control group consisted of 30 practically healthy individuals. All participants had their body mass index measured, and glomerular filtration rate was calculated using CKD-EPI equations based on creatinine, cystatin C, and their combination (CKD-EPIcysC/cr). The levels of cystatin C and ghrelin in blood serum were determined by enzyme-linked immunosorbent assay. HOMA-IR was calculated as well. Eating behaviour and its types were assessed using the Dutch Eating Behaviour Questionnaire. Results. Ghrelin levels decreased in the third group and increased in the fourth one. In patients with obesity, a significant correlation was observed between the concentration of total ghrelin and body mass index: inverse in the third group (r = –0.46, t = 2.1), and direct in fourth group (r = 0.74, t = 2.5) (p3, 4 < 0.05). Correlation analysis of cystatin C and ghrelin levels showed a direct correlation between an increase in both indicators in patients with the second stage CKD against the background of obesity. A significant direct average correlation was also found between glucose and ghrelin levels (r = 0.68, t = 2.9, p < 0.05), as well as between ghrelin concentration in blood serum and HOMA-IR (r = 0.56, t = 2.05, p < 0.05) in the fourth group. In this group, there was a close correlation between ghrelin levels and emotional type of eating behaviour (r = 0.59, t = 2.5, p < 0.05). Conclusions. As CKD progresses, changes in ghrelin levels correlate with increased cystatin C, HOMA-IR, and emotional type of eating behaviour in patients with the second stage CKD against the background of obesity. These disorders apparently contribute to glomerular damage.