The role of ghrelin, neuropeptide Y and leptin peptides in weight gain after deep brain stimulation for Parkinson's disease.

BACKGROUND The exact mechanism of weight gain (WG) after deep brain stimulation (DBS) of the subthalamic nucleus (STN) in patients with idiopathic Parkinson's disease remains unknown. OBJECTIVES To investigate a possible involvement of ghrelin, neuropeptide Y (NPY) and leptin in WG after DBS. METHODS Twenty-three Parkinson patients were submitted for body composition measurements and blood sampling 3 days before, and 3 and 6 months after STN DBS. Peripheral concentrations of ghrelin, NPY, and leptin were determined, as well as the L-dopa equivalent daily dose. Patients were clinically evaluated using the Unified Parkinson's Disease Rating Scale. RESULTS Three months after surgery, a significant WG was observed (3.09 ± 5.00 kg; p = 0.007) with no further increase at 6 months. Three months postoperatively, NPY circulating levels increased significantly (p = 0.05), while the increase of ghrelin levels reached statistical significance at 6 months (p = 0.001). WG was significantly associated with changes of ghrelin and leptin levels at 3 and 6 months, respectively. CONCLUSIONS STN DBS seems to temporarily dysregulate the hypothalamic secretion of NPY and ghrelin. The variation of weight may be attributed to an increased production of ghrelin and leptin. A possible neuroprotective role of DBS, exerted through the increase of ghrelin levels, should be further studied.