Topiramate reduces nocturnal eating in sleep-related eating disorder.

STUDY OBJECTIVES: Sleep-related eating disorder (SRED) is a parasomnia characterized by partial arousals from sleep with compulsive consumption of food with impaired level of awareness and memory for the event. Small case series' have demonstrated efficacy of topiramate in SRED. We conducted a placebo-controlled randomized clinical trial of topiramate to assess efficacy in SRED. METHODS: Thirty-four participants with an ICSD-2/ICSD-3 diagnosis of SRED with >6 months of symptoms and ≥3 sleep-related eating episodes per week were randomized to placebo or topiramate with flexible dosing to a maximum dosage of 300 mg for 13 weeks. Primary outcomes were percentage of nights with eating and Clinician Global Impression-Improvement (CGI-I). Intention-to-treat last observation carried forward (ITT LOCF) analysis was conducted. RESULTS: Mean age was 39.5 years, 74% were female, with mean duration of sleep-related eating of 13.7 years. SRED symptoms were significantly reduced with topiramate (74.7% to 33.2% nights/week; n = 15) compared to placebo (77.0% to 57.4%; n = 17) (p = 0.035). There were significantly more CGI-I responders on topiramate (71%) than placebo (27%) (p = 0.016). Level of wakefulness (r = -0.49) and memory for nighttime eating (r = -0.58) at baseline predicted topiramate response. The topiramate group lost significantly more weight than the placebo group (-8.5 lbs vs. +1.0 lbs, p = 0.001). The most common side effects were paresthesias and cognitive dysfunction. CONCLUSIONS: This first randomized controlled trial demonstrating efficacy for treatment of SRED supports preliminary data on the use of topiramate for SRED. Side effects were prominent for topiramate. Limitations include a small sample size and a high drop-out rate in both study groups. CLINICAL TRIAL INFORMATION: NCT00606411.

1H MRS Measurement of Cortical GABA and Glutamate in Primary Insomnia and Major Depressive Disorder: Relationship to Sleep Quality and Depression Severity.

BACKGROUND: Both Major Depressive Disorder (MDD) and Primary Insomnia (PI) have been linked to deficiencies in cortical γ-aminobutyric acid (GABA) and glutamate (Glu) thus suggesting a shared neurobiological link between these two conditions. The extent to which comorbid insomnia contributes to GABAergic or glutamatergic deficiencies in MDD remains unclear. METHODS: We used single-voxel proton magnetic resonance spectroscopy (1H MRS) at 4 Tesla to examine GABA+ and Glu relative to creatine (Cr) in the dorsal anterior cingulate cortex (dACC) and in the parieto-occipital cortex (POC) of 51 non-medicated adults with MDD, 24 adults with Primary Insomnia (PI), and 25 age- and sex-matched good sleeper controls (HC). Measures of depression severity and subjective and objective sleep quality were compared with 1H MRS metabolite measures. RESULTS: MDD subjects exhibited a 15% decrease in Glu/Cr in the dACC compared to HC. Within the MDD group, there was a trend inverse correlation between dACC Glu/Cr and anhedonia ratings. We observed no significant association between measures of sleep quality with dACC Glu/Cr in those with MDD. LIMITATIONS: The protocol and data interpretation would have been enhanced by the recruitment of MDD subjects with a broader range of affect severity and a more comprehensive assessment of clinical features. CONCLUSIONS: These findings support the role of cortical glutamatergic mechanisms in the pathophysiology of MDD. Insomnia severity did not further contribute to the relative deficiency of glutamatergic measures in MDD.

Identification of a bone morphogenetic protein type 2 receptor neutralizing antibody.

OBJECTIVE: The bone morphogenetic protein (BMP) signaling pathway comprises the largest subdivision of the transforming growth factor (TGFß) superfamily. BMP signaling plays essential roles in both embryonic development and postnatal tissue homeostasis. Dysregulated BMP signaling underlies human pathologies ranging from pulmonary arterial hypertension to heterotopic ossification. Thus, understanding the basic mechanisms and regulation of BMP signaling may yield translational opportunities. Unfortunately, limited tools are available to evaluate this pathway, and genetic approaches are frequently confounded by developmental requirements or ability of pathway components to compensate for one another. Specific inhibitors for type 2 receptors are poorly represented. Thus, we sought to identify and validate an antibody that neutralizes the ligand-binding function of BMP receptor type 2 (BMPR2) extracellular domain (ECD). RESULTS: Using a modified, cell-free immunoprecipitation assay, we examined the neutralizing ability of the mouse monoclonal antibody 3F6 and found a dose-dependent inhibition of BMPR2-ECD ligand-binding. Consistent with this, 3F6 blocks endogenous BMPR2 function in the BMP-responsive cell line HEK293T. The specificity of 3F6 action was confirmed by demonstrating that this antibody has no effect on BMP-responsiveness in HEK293T cells in which BMPR2 expression is knocked-down. Our results provide important proof-of-concept data for future studies interrogating BMPR2 function.

Impact of Restless Legs Syndrome on Cardiovascular Autonomic Control.

STUDY OBJECTIVES: To examine whether patients with restless legs syndrome demonstrate specific alterations in cardiovascular autonomic control. METHODS: Patients with moderate-severe restless legs syndrome (n = 20, 80% female) and controls (n = 20) matched for age, sex, body mass index, and free of hypertension and cardiovascular disease were enrolled. We assessed cardiovagal baroreflex gain via the modified Oxford technique, sympathetically mediated vascular responses to isometric exercise to fatigue, bradycardiac response to Valsalva maneuver, and respiratory sinus arrhythmia during paced breathing. Standard electrocardiography, beat-by-beat arterial pressure, respiration, and popliteal blood flow velocity were recorded continuously. RESULTS: Resting blood pressure and heart rate were similar between groups. However, baroreflex gain averaged 14.3 ± 1.4 msec/mm Hg in restless legs syndrome and was lower than in controls (22.6 ± 3.5 msec/mm Hg, P = 0.04). Hemodynamic responses to isometric exercise were similar between groups, though participants with restless legs syndrome had lower leg blood flow (P < 0.001), with greater leg vascular resistance (P < 0.0001), before and during isometric exercise. Respiratory sinus arrhythmia and Valsalva ratios were similar between groups. Neither baroreflex gain nor vascular resistance was correlated with sleep duration, sleep quality, or symptom duration. CONCLUSION: Patients with restless legs syndrome demonstrate compromised cardiovagal control, specific to the arterial baroreflex, with greater peripheral vascular resistance, potentially due to heightened sympathetic outflow. These autonomic alterations may directly relate to the higher prevalence of cardiovascular disease in restless legs syndrome.

A method to switch from oral dopamine agonists to rotigotine in patients with restless legs syndrome and mild augmentation.

BACKGROUND: We examined the short- and long-term efficacy and tolerability of a cross-titration algorithm from oral dopamine agonists to the rotigotine transdermal patch in patients dissatisfied with their restless legs syndrome (RLS) treatment, predominantly with mild augmentation. METHODS: Patients with RLS (n = 20) were recruited at a single site. The cross-titration consisted of decreasing oral dopaminergic agents (ropinirole by 1 mg or pramipexole by 0.25 mg) and increasing rotigotine by 1 mg every two days. Efficacy and adverse events (AEs) were assessed at one, three, six and 12 months after the switch. RESULTS: Patients had moderate-severe RLS symptoms at the baseline (mean international restless legs syndrome (IRLS) score 19.4 ± 5.5); 85% had augmentation and 45% reported afternoon RLS symptoms. The baseline mean pramipexole equivalent dose was 0.6 ± 0.3 mg. At Week 5, 85% (17/20) had successfully switched from their oral dopamine agonist to rotigotine (mean dose 2.5 ± 0.6 mg; change in IRLS score: -6.7 ± 8.4, p = 0.002); 14 patients were CGI-I responders (much or very much improved). Three patients withdrew due to lack of efficacy. Twelve months after cross-titration, 10 patients continued on rotigotine, of whom four required either higher doses of rotigotine or supplemental RLS medication compared with their optimal Week 5 dose; five patients withdrew due to AEs and two due to lack of efficacy. CONCLUSION: A cross-titration to rotigotine was efficacious after five weeks in 70% of patients dissatisfied with RLS treatment, most of whom had mild augmentation. At one year following the medication switch, 50% had discontinued rotigotine due to lack of continued efficacy or side effects.

Restless legs syndrome and central nervous system gamma-aminobutyric acid: preliminary associations with periodic limb movements in sleep and restless leg syndrome symptom severity.

BACKGROUND: Previous research has demonstrated abnormalities in glutamate and N-acetyl aspartate (NAA) in the thalamus in individuals with restless legs syndrome (RLS) compared with healthy matched controls. However, levels of these transmitters in other RLS-related brain areas and levels of the most common inhibitory neurotransmitter, gamma-aminobutyric acid (GABA), have not been assessed. METHODS: This study examined GABA, glutamate, and NAA levels in the dorsal anterior cingulate cortex (ACC), thalamus and cerebellum with the use of proton magnetic resonance spectroscopy ((1)H-MRS) at 4 tesla (4 T) and Megapress difference-editing in 18 subjects with RLS and a matched control group without RLS. Actigraphy was performed on the nights before scans to assess periodic limb movements of sleep (PLMS). RESULTS: Levels of GABA, glutamate, and NAA were no different between RLS and control subjects in any of the three voxels of interest. However, GABA levels were positively correlated with both PLM indices and RLS severity in the thalamus and negatively with both of these measures in the cerebellum in RLS subjects. In addition, NAA levels were higher in the ACC in RLS than in controls. CONCLUSION: Our preliminary data suggest that known cerebellar-thalamic interactions may modulate the intensity of RLS sensory and motor symptoms. In addition, anterior cingulate cortex may be associated with the affective components of the painful symptoms in this disorder.

Increased Rostral Anterior Cingulate Cortex Volume in Chronic Primary Insomnia.

BACKGROUND: Recent studies document alterations in cortical and subcortical volumes in patients with chronic primary insomnia (PI) in comparison with normal sleepers. We sought to confirm this observation in two previously studied PI cohorts. METHODS: Two separate and independent groups of unmedicated patients who met Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition (DSM-IV) criteria for PI were compared with two separate, healthy control groups (Study 1: PI = 20, controls = 15; Study 2: PI = 21, controls = 20). Both studies included 2 weeks of sleep diaries supplemented by wrist actigraphy. The 3.0 T MRI-derived rostral anterior cingulate cortex (rACC) volumes were measured with FreeSurfer image analysis suite (version 5.0) and results normalized to total intracranial volume (ICV). Unpaired t-tests (two-tailed) were used to compare rACC volumes between groups. Post hoc correlations of rACC volumes to insomnia severity measures were performed (uncorrected for multiplicity). RESULTS: Both studies demonstrated increases in normalized rACC volume in PI compared with control patients (Study 1: right side P = 0.05, left side P = 0.03; Study 2: right side P = 0.03, left side P = 0.02). In PI patients from Study 1, right rACC volume was correlated with sleep onset latency (SOL) by both diary (r = 0.51, P = 0.02) and actigraphy (r = 0.50, P = 0.03), and with sleep efficiency by actigraphy (r = -0.57, P = 0.01); left rACC volume was correlated with SOL by diary (r = 0.48, P = 0.04), and wake after sleep onset (WASO) (r = 0.49, P = 0.03) and sleep efficiency (r = -0.49, P = 0.03) by actigraphy. In Study 2, right rACC volume was correlated with SOL by diary (r = 0.44, P = 0.05) in PI patients. CONCLUSIONS: Rostral ACC volumes are larger in patients with PI compared with control patients. Clinical severity measures in PI correlate with rACC volumes. These data may reflect a compensatory brain response to chronic insomnia and may represent a marker of resilience to depressive illness. CITATION: Winkelman JW; Plante DT; Schoerning L; Benson K; Buxton OM; O'Connor SP; Jensen JE; Renshaw PF; Gonenc A. Increased rostral anterior cingulate cortex volume in chronic primary insomnia. SLEEP 2013;36(7):991-998.

Reduced γ-aminobutyric acid in occipital and anterior cingulate cortices in primary insomnia: a link to major depressive disorder?

Insomnia is closely related to major depressive disorder (MDD) both cross-sectionally and longitudinally, and as such, offers potential opportunities to refine our understanding of the neurobiology of both sleep and mood disorders. Clinical and basic science data suggest a role for reduced γ-aminobutyric acid (GABA) in both MDD and primary insomnia (PI). Here, we have utilized single-voxel proton magnetic spectroscopy (1H-MRS) at 4 Tesla to examine GABA relative to total creatine (GABA/Cr) in the occipital cortex (OC), anterior cingulate cortex (ACC), and thalamus in 20 non-medicated adults with PI (12 women) and 20 age- and sex-matched healthy sleeper comparison subjects. PI subjects had significantly lower GABA/Cr in the OC (p=0.0005) and ACC (p=0.03) compared with healthy sleepers. There was no significant difference in thalamic GABA/Cr between groups. After correction for multiple comparisons, GABA/Cr did not correlate significantly with insomnia severity measures among PI subjects. This study is the first to demonstrate regional reductions of GABA in PI in the OC and ACC. Reductions in GABA in similar brain regions in MDD using 1H-MRS suggest a common reduction in cortical GABA among PI and mood disorders.