Body Weight Regulation in Patients With Narcolepsy
Body Weight Regulation in Patients With Narcolepsy
This study will measure energy expenditure (the rate at which the body burns calories),
 physical activity and caloric intake in people with narcolepsy to learn more about how the
 risk of becoming overweight or diabetic may be affected.

 Healthy control subjects and people with narcolepsy between 18 and 55 years of age may be
 eligible for this study. Participants are withdrawn from their narcolepsy medication and
 undergo the following tests and procedures over 5 weeks before resuming medications.

 -  Blood draw for genetic studies.

 -  Collection of a cerebrospinal fluid sample.

 -  Diet to keep subjects' weight constant.

 -  Activity watch, using a device worn on the wrist to measure amount of movement, and an
 activity monitor worn at the waist to measure physical activity and caloric expenditure.

 -  Questionnaires about sleepiness, symptoms, food intake, exercise and mood.

 -  24-hour urine collection and 24-hour blood draw to measure hormones.

 -  Glucose tolerance test. The subject drinks a sugar solution and blood samples are
 collected through a catheter before drinking the solution and 30 minutes, 1, 2 and 3
 hours after drinking it.

 -  Startle reflex test. Subjects hear a loud noise through headphones and are asked to look
 at pictures.

 -  Sleep study to evaluate sleep-related breathing disturbances and record information
 about sleep stages.

 -  Indirect calorimetry test to measure how fast the body uses calories. A plastic canopy
 is placed over the face for several minutes to capture the air exhaled to analyze oxygen
 use. To measure the energy associated with meals, the same measurements are taken after
 the subject eats lunch.

 -  CT scan of the abdomen to see how much fat is deposited in the abdomen, and DEXA scan of
 the whole body to see the percentage of fat and muscle.

 -  Plethysmography. Participants sit in an enclosed chamber while the mass and volume of
 the body are measured by changes in air pressure.

 -  Neuropsychological testing to assess thought processes.

 -  Continuous 24-hour heart rate measurement.

 -  Metabolic chamber. Subjects spend 24 hours in a small room to measure the amount of
 oxygen inhaled and carbon dioxide exhaled.

 -  Walking/running test to assess level of physical conditioning.

 -  Dexamethasone CRH (corticotropin-releasing hormone) suppression test and CRH stimulation
 test. Subjects receive eight doses of 0.5 mg dexamethasone every 6 hours for a day and a
 half. After the last dose, two blood samples are drawn, then a dose of CRH is injected,
 and then six more blood samples are drawn over the next 3 hours.

 -  TRH (thyrotropin-releasing hormone) stimulation test. Subjects are given TRH through a
 vein, and several blood samples are then drawn over the next 3 hours.

 -  Doubly labeled water test. Subjects drink a dose of "heavy" water. Urine samples are
 collected at 2, 3 and 5 hours after drinking and again for two 4-hour collections a week
 later.
BACKGROUND: Several cross-sectional studies have suggested that subjects with narcolepsy have
 increased body mass index (BMI) and insulin resistance. These subjects exhibit a decrease in
 cerebrospinal fluid (CSF) orexin levels, which has been causally linked to the clinical
 manifestations of this disease. Orexins are peptides expressed in a brain region, the lateral
 hypothalamic area, which stimulate appetite and modulate sleep. Low CSF orexin levels provoke
 narcolepsy-like behavior, such as excessive daytime sleepiness and a sudden loss of muscle
 tone known as cataplexy.

 OBJECTIVES: The primary objective of this study is to determine whether subjects with
 narcolepsy have lower energy expenditure compared to healthy matched controls. In addition,
 we will assess food intake, physical activity, and other relevant parameters.

 STUDY POPULATION: 18 to 55 year old men and premenopausal women with narcolepsy and healthy
 matched controls

 DESIGN: This is a cross-sectional, case-controlled study of subjects with narcolepsy matched
 on a one-to-one basis with healthy, non-narcoleptic control subjects.

 OUTCOME PARAMETERS: We will assess metabolic, hormonal, and energy expenditure parameters in
 subjects with narcolepsy. Outcomes: energy expenditure by various methods (indirect
 calorimetry, metabolic chamber, doubly-labeled water method); leptin circadian levels
 (frequent 24h sampling); physical activity, characterization of the main endocrine axes, and
 other relevant parameters.
-  INCLUSION CRITERIA:

 Patients

 -18 to 55 year old men and pre-menopausal women with current narcolepsy, otherwise healthy.

 Controls

 -18 to 55 year old healthy men and pre-menopausal women.

 SUBJECTS WITH NARCOLEPSY INCLUSION:

 -  Having a current diagnosis of narcolepsy with moderate or severe daytime sleepiness
 for at least 6 months, according to the International Classification of Sleep Disorder
 (ICSD).

 -  Both new and previously diagnosed patients are eligible.

 -  Females of childbearing potential must have a negative serum pregnancy test.

 -  A valid barrier contraception method is required over the duration of the study.

 -  Patients must agree to refrain from operating a motor vehicle and from being involved
 in any other potentially hazardous activity during the tapering off and the drug-free
 periods.

 SUBJECTS WITH NARCOLEPSY EXCLUSION:

 -  Pregnancy and lactation (women only)

 -  Use of birth control pills

 -  Menopause, defined as 6 consecutive months without mensis

 -  Clinical diagnosis of polycystic ovary disease, chronic history of anovulatory cycles
 or other alterations of the menstrual cycle (for women only)

 -  Use of any experimental drug or current participation in another research protocol

 -  Chronic amphetamines in the last 2 months and any drug known to influence the
 autonomic nervous system including appetite suppressants

 -  Excessive daytime sleepiness (EDS) related to:

 -  Sleep apnea

 -  Periodic limb movements

 -  Substance disorder or alcohol consumption

 -  Any concurrent psychiatric, neurological, neoplastic, endocrinologic, or infectious
 disease that may contribute to EDS

 -  Insufficient sleep (less than 6 hours/night) or any other known cause inducing
 sleepiness

 -  Working in an occupational environment that requires variable or routine night shifts

 -  History of head trauma or history of seizure

 -  Agitated state or severe anxiety, moderate or severe psychosis or dementia

 -  Current major depression (Hamilton score greater than 18), subjects currently
 receiving pharmacological treatment for depression (even if their Hamilton score is
 lower than 18), anyone who has or had suicidal ideation

 -  Dyskinesia or other neurological conditions

 -  Use of any medications that may influence sleep or contribute to EDS, except for
 anticataplectic medications, including:

 Hypnotic, anxiolytic, chronic amphetamine use, antidepressants, antihistamine, clonidine,
 anticonvulsants

 -  Hyperthyroidism or hypothyroidism

 -  Symptomatic cardiac disease

 -  For those subjects consenting to the exercise test (Cooper test)

 Any medical contraindication to exercise of moderate intensity and short duration including
 cardiovascular or respiratory conditions, morbid obesity, and severe osteoarthritis of the
 lower extremities

 -  Chronic illicit drug use

 -  Use of antipsychotic drugs

 -  Narcoleptic subjects with coexistent significant sleep apnea or respiratory
 disturbances are excluded

 -  Major cardiac rhythm disturbances, respiratory rate alterations, or any other major
 organ disease that would make the interpretation of HRV data arduous

 -  Fever

 EXCLUSION RELATED TO THE METABOLIC STATUS:

 -  Weight fluctuations defined as increase or decrease in body weight greater than 5%
 over the last 3 months

 -  Unstable physical activity in the 3 months prior to study entry

 -  Any secondary cause of obesity, including:

 -  Cushing syndrome, hypothyroidism, GH and testosterone deficiency, polycystic ovarian
 syndrome, insulinoma, hypothalamic lesions, and genetic obesity syndromes such as
 Prader-Willy and other genetic syndromes

 -  Obesity-related medical conditions requiring pharmacological treatment

 -  Insulin-dependent diabetes mellitus

 -  Uncontrolled hypertension

 -  Uncontrolled hyperlipidemia

 -  Current smoking, defined as more than 2 cigarettes/day

 -  Strict vegetarian diet, defined as lack of milk, eggs, and diary products

 HEALTHY CONTROL SUBJECT INCLUSION/EXCLUSION:

 -In addition to the criteria specified above, healthy controls must be in good physical
 health and not on chronic medications.