title: Change of the melanocortin system caused by bilateral subthalamic nucleus stimulation in Parkinson's disease.
abstract: OBJECTIVES - Determine whether bilateral subthalamic nucleus stimulation (STN-DBS) in Parkinson's disease (PD) is associated with an increase in neuropeptide Y (NPY) and/or resistance to inhibition by leptin in relation to post-surgery weight gain. MATERIALS AND METHODS - This prospective study included 20 patients who underwent bilateral STN-DBS and 17 who refused surgery. Data were obtained at baseline, 3 and 6 months on neurological and nutritional status, including determination of body mass index (BMI) and serum NPY and leptin levels. RESULTS -  NPY and leptin levels changed over time, with a distinct pattern. The BMI increase at 6 months was greater in the surgical group (5.5 ± 6.3% vs 0.5 ± 3.5%; P = 0.035). Medical group exhibited a reduction in leptin level (-2.0 ± 4.3 ng/ml) and a consequent increase in NPY level (72.4 ± 58.7 pmol/ml). However, STN-DBS patients showed an increase in leptin (3.1 ± 5.0 ng/ml; P = 0.001 vs medical group) and also in NPY (12.1 ± 53.6 pmol/ml; P = 0.022 vs medical group) levels, which suggests resistance to inhibition by leptin. Rise in NPY level correlated with higher stimulation voltages. CONCLUSIONS -  Bilateral STN-DBS causes disruption of the melanocortin system, probably related to diffusion of the electric current to the hypothalamus. This mechanism may in part explain the weight gain of patients with PD after surgery.
authors.affiliation: Departments of Neurology             Neurosurgery             Endocrinology             Nuclear Medicine, 'Virgen de las Nieves' University Hospital, Granada, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Escamilla-Sevilla
authors.forename: M J
authors.initials: MJ
authors.lastname: Pérez-Navarro
authors.forename: M
authors.initials: M
authors.lastname: Muñoz-Pasadas
authors.forename: C
authors.initials: C
authors.lastname: Sáez-Zea
authors.forename: M
authors.initials: M
authors.lastname: Jouma-Katati
authors.forename: G
authors.initials: G
authors.lastname: Piédrola-Maroto
authors.forename: A
authors.initials: A
authors.lastname: Ramírez-Navarro
authors.forename: A
authors.initials: A
authors.lastname: Mínguez-Castellanos
mesh_terms: D000368:Aged; D015992:Body Mass Index; D004599:Electric Stimulation Therapy / Q000009:adverse effects*; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D053486:Melanocortins / Q000378:metabolism; D008875:Middle Aged; D009478:Neuropeptide Y / Q000097:blood*; D010300:Parkinson Disease / Q000628:therapy*; D011446:Prospective Studies; D020531:Subthalamic Nucleus / Q000502:physiology*; D016896:Treatment Outcome; D015430:Weight Gain / Q000502:physiology*
chemical_list: D020738:Leptin; D053486:Melanocortins; D009478:Neuropeptide Y