Cerebrospinal fluid ghrelin is negatively associated with body mass index.

Ghrelin is a 28 amino acid peptide hormone, predominantly expressed in the gastric epithelium and, at a lower level, in the hypothalamus. Although several lines of evidence indicate that ghrelin has a role in appetite regulation, nevertheless the regulation and role of central ghrelin levels remain unclear. To further characterize the role of ghrelin in the regulation of body adiposity, we investigated the association between fasting cerebrospinal fluid (CSF) ghrelin levels and body mass index (BMI) in humans. We consecutively enrolled 19 adults (aged 21-76 yr, 15 females and 4 males), including 4 obese, 7 overweight and 8 lean subjects, who underwent spinal anesthesia during surgery for non-malignant conditions. We found a negative association between fasting CSF ghrelin levels and BMI (r = -0.48, p = 0.035) and a trend towards lower (by 16%) fasting CSF ghrelin levels in the obese (p = 0.06 for the difference between lean and obese subjects). In conclusion, we found a negative association between fasting CSF ghrelin levels and BMI in humans. Our data suggest that central ghrelin may have a role in the regulation of body adiposity in humans, which requires further study to be fully elucidated.