Armodafinil for sarcoidosis-associated fatigue: a double-blind, placebo-controlled, crossover trial

CONTEXT

Fatigue has been identified in more than one-half of patients with sarcoidosis. Although fatigue is not synonymous with impaired quality of life, most studies of sarcoidosis identify fatigue as a major cause of impaired quality of life.

OBJECTIVES

To test the hypothesis that stimulants may have a role in the treatment of fatigued sarcoidosis patients, even without objective evidence of daytime sleepiness.

METHODS

This was a double-blind, placebo-controlled, crossover study of sarcoidosis patients followed up in one sarcoidosis clinic Sarcoidosis patients with fatigue received either armodafinil or placebo with eight weeks of therapy for each arm and a two week washout period before crossover to the other treatment. Initial armodafinil dose was 150mg and increased to 250mg after four weeks. Patients underwent polysomnography and multiple sleep latency testing (MSLT) the following day. Patients with an apnea/hypopnea index <6/hour received either armodafinil or placebo. Polysomnography with MSLT was repeated after each treatment arm.

RESULTS

Fifteen patients received the study drug. Fatigue was assessed using the Fatigue Assessment Scale (the lower the score, the less the fatigue) and the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) (the higher the score, the less the fatigue). After eight weeks of therapy, there was a significant improvement in the Fatigue Assessment Scale during armodafinil treatment (median -4.5, range -20, 5) compared with placebo treatment (median 3.5, range -9, 14, P<0.05) and for the FACIT-F (armodafinil: median 9, range -12, 26 vs. placebo: median -5, range -17, 11, P<0.005). This improvement in fatigue was seen for both those with and without shortened sleep onset latency time during the MSLT.

CONCLUSION

Armodafinil treatment led to a significant reduction in fatigue in sarcoidosis patients. This effect was seen even in patients who did not have excessive daytime somnolence.

Use of ramelteon for the treatment of secondary REM sleep behavior disorder

We used ramelteon to treat two patients with secondary REM sleep behavior disorder (RBD) complications along with neurodegenerative diseases including multiple system atrophy and Parkinson's disease. These two patients not only improved in terms of their clinical RBD symptoms but also exhibited a decrease in the proportion of REM sleep without atonia (from 8.5% to 3.5% and from 10.9% to 3.9% in the two patients). Although clonazepam is the standard first-line therapy for the treatment of RBD, ramelteon might be an effective treatment alternative in patients with RBD who cannot take clonazepam due to either ineffectiveness or adverse effects.

Genetic basis of apnoea of prematurity and caffeine treatment response: role of adenosine receptor polymorphisms: genetic basis of apnoea of prematurity

AIM

Caffeine treatment reduces the frequency of apnoea of prematurity (AOP) and eliminates the need for mechanical ventilation by acting as a nonspecific inhibitor of adenosine A1 and adenosine 2A receptors. Patients with AOP have demonstrated variant responses to caffeine therapy. We proposed to investigate the role of A1 and 2A polymorphisms in the development of AOP and individual differences in caffeine response. Secondly, we aimed to determine whether these polymorphisms have any effect on bronchopulmonary dysplasia (BPD) development.

METHODS

Cord blood samples were collected from infants born with gestational ages between 24 and 34 weeks. Two groups were defined: patients without apnoea (n = 60) and patients with apnoea (n = 55). Patients with apnoea were divided into two subgroups: a caffeine-responsive group (n = 30) and an unresponsive group (n = 25). Six single-nucleotide polymorphisms were chosen for genotyping.

RESULTS

Patients with apnoea over 28 weeks of gestational age who responded to the caffeine treatment were found to carry the rs16851030 C/C genotype rather than the C/T or T/T genotype. Logistic regression analysis showed a significant correlation between rs35320474-C/T and T/T genotypes and apnoea and BPD development.

CONCLUSION

Our results indicate a role for adenosine receptor gene polymorphisms in susceptibility to AOP and BPD and in interindividual variability to caffeine response.

Melatonin - a somniferous option which does not aggravate sleep-disordered breathing in cardiac risk patients: a Holter ECG based study

BACKGROUND AND AIM

We hypothesised that melatonin may represent a safe somniferous drug for cardiac patients, and assessed the effects of administering 5 mg of melatonin daily before bedtime for 30 days in patients with coronary artery disease (CAD) regarding changes in the nocturnal breathing pattern.

METHODS

Sixty patients with CAD (aged 48-80 years) were randomised to melatonin/placebo treatment in a 2:1 ratio. A Holter ECG-based method (Lifescreen Apnea software) which has been validated as a screening tool for sleep-disordered breathing was used to estimate the apnoea/hypopnoea index (AHI). A 24-h Holter ECG was used to detect nocturnal breathing abnormalities at the beginning and at the end of the observation. The values of estimated AHI (eAHI) ≤ 15 were classified as optimal (Opt) and those 〉 15 - as pathological (Pat). A change of the breathing pattern was classified on the basis of the transition between the initial and final eAHI status (Opt→Opt; Opt→Pat; Pat→Pat, Pat→Opt). The mean initial and final value of eAHI and the percent of Opt and Pat values of eAHI in the initial and final assessment were compared between the melatonin and the placebo groups.

RESULTS

The breathing pattern was not affected by melatonin - the mean initial value of the eAHI in the melatonin group was 18.2 ± 9.4, and in the placebo group 19.6 ± 12.3 (p = 0.64), whereas at the end of the observation in the melatonin group it increased by 1.2 ± 11.3, and in the placebo group - by 1.0 ± 9.0 (p = 0.44).

CONCLUSIONS

Hypnagogic treatment with melatonin did not worsen the eAHI in patients with CAD.

Effects of 5-hydroxytryptamine and 5-hydroxytryptamine 2A/2C agonist on the genioglossus activity and sleep apnea in rats

BACKGROUND

5-Hydroxytryptamine (5-HT) is a common neurotransmitter in the brain which plays an important role in the pathogenesis of sleep apnea. Dysfunction of 5-HT and 5-HT(2) receptors may lead to the collapse of the upper airway and the instability of respiratory control, which in turn produce apnea. Genioglossus (GG) is one of the most important oropharyngeal muscles maintaining the upper airway open. The present study aimed to investigate the effects of 5-HT and 5-HT(2) receptor on GG activity and the sleep apnea in Sprague-Dawley (SD) rats.

METHODS

Microinjection probes were placed within the fourth ventricle of sixteen SD rats. After recovery for a week, the electromyogram (EMG) of GG was recorded in the anesthetized and vagotomized rats. The changes of GG activity before and after the microinjection of 5-HT or 5-HT(2A/2C) agonist -2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI) were observed. Probes were also laid in another eight SD rats. Electroencephalogram (EEG), EMG of neck muscle and respiration were recorded at the same time a week later. The effects of DOI on the occurrence of sleep apnea were explored.

RESULTS

Both 5-HT and DOI significantly enhanced the activity of GG just 3 minutes after the completion of injection. The effect of 5-HT disappeared quickly and the effect of DOI lasted for more than 27 minutes. DOI also significantly decreased the post-sigh apnea index in non-rapid-eye-movement (NREM) and rapid-eye-movement (REM) sleep and decreased the spontaneous apnea index only in NREM sleep (P < 0.05, respectively).

CONCLUSION

5-HT and 5-HT(2A/2C) system correlated closely with the pathogenesis of the sleep apnea syndrome and 5-HT receptors may become the target of the drug treatment.

Comparison of the effects of nebivolol and valsartan on BP reduction and sleep apnoea activity in patients with essential hypertension and OSA

OBJECTIVES

To investigate the effect of nebivolol, a third generation beta-blocker, on blood pressure (BP) reduction and polysomnographic parameters in hypertensive patients with mild-to-moderate obstructive sleep apnoea (OSA).

METHODS

In this double-blind, parallel group study, patients were randomized to nebivolol 5 mg or valsartan 80 mg once daily following a 14-day, placebo run-in period during which any antihypertensive medication were discontinued. BP and heart rate measurements and overnight polysomnography were performed at baseline and after 6 weeks of treatment. Safety and tolerability were assessed.

RESULTS

Thirty-one patients were randomized to nebivolol (n = 16) or valsartan (n = 15). After six weeks both systolic and diastolic BP were effectively reduced by both treatments. Reductions in BP were not statistically significant different between agents, but mean heart rate was significantly decreased with nebivolol (compared with valsartan (p < 0.001). There was no statistically significant difference between both treatments for the change from baseline to treatment end for mean (+/-SD) Apnoea Hypopnoea Index (AHI) (nebivolol: 23.0 +/- 9.2 to 27.9 +/- 21.2 events/h; valsartan: 23.8 +/- 6.6 to 22.5 +/- 18.0 events/h; p = 0.48) or for any other sleep-related parameters. Both agents were well tolerated.

CONCLUSION

Nebivolol has a significant BP reduction effect in patients with OSA that is similar to valsartan and reduces heart rate to a greater extent which may prove beneficial in selected patients.

[Effects of 5-HT2 agonist/antagonist on sleep apnea in Sprague-Dawley rats]

OBJECTIVE

To evaluate the effects of 5-HT2 agonist/antagonist Ketanserin on sleep apnea in Sprague-Dawley (SD) rats.

METHODS

Twenty adult male SD rats were operated for implantation of EEG and EMG electrodes and a microinjection probe was placed within the fourth ventricle. After recovery for a week, rats were monitored for sleep and respiration in three continuous days. There is no intervention on the first day. Before monitoring, 40 microl ACSF were microinjected into the IV ventricle of the rats on the second day. On the third day before monitoring, 40 microl DOI were microinjected into the IV ventricle of ten rats and 40 microl Ketanserin into another ten ones.

RESULTS

Compared with blank control and microinjection of ACSF, DOI significantly reduced the total apnea index (AI) from 18.3 (11.1, 20.3) times/h and 15.2 (11.4, 18.0) times/h to 10.8 (3.1, 14.1) times/h (P=0.005 and 0.005, respectively). Post sign apnea index (PSAI) during non-rapid eye movement (NREM) and rapid eye movement (REM) sleep as well as spontaneous apnea index (SPAI) during NREM sleep were all significantly decreased; (P<0.05, respectively); while it had no effect on SPAI during REM sleep (P>0.05). Neither sleep efficiency (the percent of total sleep time in total monitoring time) nor the time ratio of NREM sleep and REM sleep was significantly changed. In contrast to blank control and microinjection of ACSF, Ketanserin significantly reduced the total apnea index (AI) from 19.2 (13.7, 20.9) times/h and 19.0 (12.9, 21.6) times/h to 13.1 (9.5, 14.9) times/h (P=0.005 and 0.005, respectively). PSAI during NREM and REM sleep were significantly decreased (P<0.05, respectively). SPAI during NREM and REM sleep were changed without statistically significant (P>0.05, respectively). It also had no effects on sleep efficiency and the time ratio of NREM sleep and REM sleep.

CONCLUSION

Both 5-HT2 agonist and antagonist decreased the sleep apnea index and had no effects on sleep structure. It shows that the role of 5-HT2 receptor in the respiratory regulation during sleep is complex. The mechanisms involved remain to be studied in future.

Proof of concept study: does fenofibrate have a role in sleep apnoea syndrome?

OBJECTIVE

To investigate the effect of fenofibrate on sleep apnoea indices.

METHODS

Proof-of-concept study comprising a placebo run-in period (1 week, 5 weeks if fibrate washout was required) and a 4-week randomized, double-blind treatment period. Thirty-four subjects (mean age 55 years, body mass index 34 kg/m 2 , fasting triglycerides 3.5 mmol/L) with diagnosed sleep apnoea syndrome not treated with continuous positive airways pressure were enrolled and randomized to once daily treatment with fenofibrate (145 mg NanoCrystal(R) tablet) or placebo. Overnight polysomnography, computerized attention/vigilance tests and blood sampling for measurement of lipids, insulin, fasting plasma glucose and fibrinogen were performed at the end of each study period.

CLINICAL TRIAL REGISTRATION

NCT00816829.

MAIN OUTCOME MEASURES

As this was an exploratory study, a range of sleep variables were evaluated. The apnoea/hypopnoea index (AHI) and percentage of time spent with arterial oxygen saturation (SpO(2)) <90% were relevant as they have been evaluated in other clinical trials. Other variables included total apnoeas, hypopnoeas and oxygen desaturations, and non-cortical micro-awakenings related to respiratory events per hour.

RESULTS

Fenofibrate treatment significantly reduced the percentage of time with SpO(2) <90% (from 9.0% to 3.5% vs. 10.0% to 11.5% with placebo, p = 0.007), although there was no significant change in the AHI (reduction vs. control 14% (95%CI -47 to 40%, p = 0.533). Treatment reduced obstructive apnoeas (by 44%, from 18.5 at baseline to 15.0 at end of treatment vs. 29.0 to 30.5 on placebo, p = 0.048), and non-cortical micro-awakenings per hour (from 23.5 to 18.0 vs. 24.0 to 25.0 with placebo, p = 0.004). Other sleep variables were not significantly influenced by fenofibrate.

KEY LIMITATIONS

Exploratory study in patients with mild to moderate sleep apnoea, limited treatment duration; concomitant hypnotic treatment (35%); lack of correction for multiplicity of testing.

CONCLUSIONS

The consistent direction of change in sleep indices in this proof-of-concept study may support further investigation of fenofibrate in moderate to severe sleep apnoea syndrome.

Melatonin and sleep-related problems in children with intractable epilepsy

Children with epilepsy have high rates of sleep problems. Melatonin has been advocated in treatment of sleep disorders, and its beneficial effect has been confirmed in insomnia. The aim of this study was to assess melatonin levels in children with intractable epilepsy and its relation to pattern of sleep and characteristics of seizure disorder, as well as the effect of melatonin therapy on those parameters. The study was conducted on 23 children with intractable epilepsy and 14 children with controlled seizures. Patients were evaluated by psychometric sleep assessment and assay of diurnal and nocturnal melatonin levels. Children with intractable epilepsy received oral melatonin before bedtime. They were reassessed after 3 months. Children with intractable epilepsy had higher scores for each category of sleep walking, forcible teeth grinding, and sleep apnea. At the end of therapeutic trial, patients with intractable epilepsy exhibited significant improvement in bedtime resistance, sleep duration, sleep latency, frequent nocturnal arousals, sleep walking, excessive daytime sleepiness, nocturnal enuresis, forcible teeth grinding, sleep apnea, and Epworth sleepiness scores. There was also significant reduction in seizure severity. Thus, use of melatonin in patients with intractable seizures was associated with improvement of both many sleep-related phenomena and the severity of seizures.

[Dopaminergic stimulation in the non-motor symptoms of Parkinson's disease]

INTRODUCTION AND DEVELOPMENT

The non-motor symptoms of Parkinson's disease have a great impact in terms of quality of life. They are frequently underdiagnosed and clinical experience suggests that not only is dopamine therapy ineffective but that in many cases it is also responsible for the appearance of some of these symptoms. Different studies have drawn attention to the involvement of the dopaminergic pathways in the pathogenesis of some non-motor symptoms. It has been observed that they can undergo fluctuations in relation to dopaminergic stimulation, generally in wearing off states, while displaying a significant correlation with motor fluctuations and a clinical response with continuous dopaminergic therapy.

CONCLUSIONS

Although recent reviews offer insufficient evidence for treatment of non-motor symptoms with dopaminergic therapy, involvement of the dopaminergic pathways in the aetiopathogenesis of some of these disorders and the clinical observation that such symptoms undergo fluctuations in relation to pulsatile dopaminergic stimulation may lead us to reconsider the possible role of dopaminergic therapy in the treatment of these symptoms.

Influence of disease control with pegvisomant on sleep apnoea and tongue volume in patients with active acromegaly

OBJECTIVES

Sleep apnoea has been consistently reported to occur in acromegaly. In uncontrolled patients, the severity of sleep apnoea influences physical activity in the daytime. We investigated the influence of disease activity on tongue volume and sleep apnoea treated with the GH receptor antagonist pegvisomant in poorly controlled patients with acromegaly under octreotide.

DESIGN AND METHODS

A total of 12 patients with active acromegaly (six females; six males; mean age 57+/-15 years; body mass index 29.4+/-4.2 kg/m(2); mean+/-S.D.) were treated with pegvisomant (13.5+/-5.0 mg/die) for 6 months. Tongue volume was examined by magnetic resonance imaging, and sleep apnoea was characterized by polysomnography before and after 6 months of treatment with pegvisomant. The mandibular length was determined by lateral X-ray films.

RESULTS

IGF1 levels decreased after 6 months in all patients (407+/-114 to 199+/-23 microg/l; P=0.0001). The tongue volume decreased (105+/-33 to 83+/-33 ml; P=0.007) as well as the apnoea-hypnoea index (23+/-22 to 18+/-18/h; P=0.0066). The mandibular length correlated with the initial tongue volume (r(2)=0.6072, P=0.0028).

CONCLUSION

In conclusion, successful treatment with pegvisomant can decrease tongue volume, which has benefits for coexisting sleep disordered breathing.

Central cholinergic regulation of respiration: nicotinic receptors

Nicotinic acetylcholine receptors (nAChRs) are expressed in brainstem and spinal cord regions involved in the control of breathing. These receptors mediate central cholinergic regulation of respiration and effects of the exogenous ligand nicotine on respiratory pattern. Activation of alpha4* nAChRs in the preBötzinger Complex (preBötC), an essential site for normal respiratory rhythm generation in mammals, modulates excitatory glutamatergic neurotransmission and depolarizes preBötC inspiratory neurons, leading to increases in respiratory frequency. nAChRs are also present in motor nuclei innervating respiratory muscles. Activation of post- and/or extra-synaptic alpha4* nAChRs on hypoglossal (XII) motoneurons depolarizes these neurons, potentiating tonic and respiratory-related rhythmic activity. As perinatal nicotine exposure may contribute to the pathogenesis of sudden infant death syndrome (SIDS), we discuss the effects of perinatal nicotine exposure on development of the cholinergic and other neurotransmitter systems involved in control of breathing. Advances in understanding of the mechanisms underlying central cholinergic/nicotinic modulation of respiration provide a pharmacological basis for exploiting nAChRs as therapeutic targets for neurological disorders related to neural control of breathing such as sleep apnea and SIDS.

[Neurobiology of sleep apnea: implication for therapy?]

An accumulating body of evidence from animal investigations supports the potential importance of vagal afferent pathways in the pathogenesis and/or therapy of SRBD. The neurochemistry and neuropharmacology of this pathway offers numerous possible targets for pharmacologic modulation. Defining the ultimate clinical relevance of these pathways in SRBD pathogenesis and treatment can only be accomplished with significant ongoing clinical and basic investigation.

The 5-min pupillary alertness test is sensitive to modafinil: a placebo controlled study in patients with sleep apnea

RATIONALE

The extent of pupillary miosis during 5 min in darkness is a simple, recently introduced alertness test which may become useful in the clinical assessment of normal and pathological sleepiness.

OBJECTIVES

In this study, we further validated this test by testing its sensitivity to the effects of modafinil, a non-stimulant, alertness-promoting drug.

METHODS

Twelve unmedicated patients recently diagnosed with obstructive sleep apnea (OSA) after polysomnography, received placebo or modafinil (200 mg), according to a double-blind, cross-over design. The patients' resting pupil diameter (RPD) was sampled over 5 min in darkness before (10:00 A.M.) and after treatment (2:00 P.M.), and their light reflexes were elicited and recorded in darkness with an infrared video pupillometer.

RESULTS

We found a circadian miosis at 2:00 P.M. in the placebo treatment condition, which was reversed by modafinil. This effect correlated with modafinil-induced increase in subjective alertness, and it was greater in the most severely affected patients in terms of lowest oxygen saturation, independently of body mass index, age, or apneic episodes during sleep. Modafinil reduced the light reflex amplitude, suggesting an increase in the inhibitory input at the pupilloconstrictor Edinger-Westphal nucleus.

CONCLUSIONS

These effects of modafinil are best explained via an activation of the hypoxia-sensitive nucleus locus coeruleus. The 5-min pupillary alertness test has promising predictive validity, and it holds promise as a fast and sensitive method for the objective assessment of excessive daytime sleepiness, monitoring of disease progression, and response to treatment.

Severe sleep-disordered breathing in a patient with Brown–Vialetto–Van Laere syndrome: Polysomnographic findings

Brown-Vialetto-Van Laere (BVVL) syndrome is a rare disorder with clinical features that include progressive bilateral sensorineural deafness and a variety of cranial nerve impairments. Respiratory compromise has been observed in most familial and sporadic cases; however, few studies have been published regarding sleep-disordered breathing in this syndrome. We report the unique case of a 16-year-old girl with the clinical features of BVVL syndrome who presented with bilateral sensorineural hearing loss and then progressively developed paralysis of the 7th and 9th-12th cranial nerves. More importantly, she presented with the unusual feature of severe sleep-disordered breathing. A polysomnographic study showed evidence of dominant central sleep apnea, and the majority of apneic episodes more likely occurred in stage 2 during NREM sleep. The central sleep apnea was associated with rapid respiratory deterioration and death. This report raises the fact that a patient with BVVL syndrome may present with severe sleep-disordered breathing as a life-threatening condition, which emphasizes the need for greater attention to the early detection of potential sleep-disordered breathing in these afflicted with the BVVL syndrome for optimal clinical management.

Hypothalamic-pituitary-adrenal axis activity in obese men with and without sleep apnea: effects of continuous positive airway pressure therapy

CONTEXT

Previous studies on the association between the hypothalamic-pituitary-adrenal axis activity and sleep apnea (SA) and obesity are inconsistent and/or limited.

OBJECTIVE

In this study, we evaluated the activity of the hypothalamic-pituitary-adrenal axis in nonpsychologically distressed obese subjects with and without SA and examined the impact of continuous positive airway pressure (CPAP) in SA patients.

DESIGN AND PARTICIPANTS

In study I, four-night sleep laboratory recordings and serial 24-h plasma measures of cortisol were obtained in 45 obese men with and without apnea and nonobese controls. Sleep apneic patients were reassessed after 3 months of CPAP use. In study II, 38 obese men with and without sleep apnea and nonobese controls were challenged with ovine CRH administration after four nights in the sleep laboratory.

RESULTS

The sleep patterns were similar between obese and nonobese controls. Twenty-four-hour plasma cortisol levels were highest in nonobese controls, intermediate in obese apneic patients, and lowest in obese controls (8.8 +/- 0.4 vs. 8.1 +/- 0.3 vs. 7.5 +/- 0.3 microg/dl, P < 0.05). CPAP tended to reduce cortisol levels in the apneic patients (difference -0.7 +/- .4 microg/dl, P = 0.1). CRH administration resulted in a higher ACTH response in both obese groups, compared with nonobese controls; the three groups were not different in cortisol response.

CONCLUSIONS

Nonpsychologically distressed, normally sleeping, obese men had low cortisol secretion. The cortisol secretion was slightly activated by SA and returned to low by CPAP use. The low cortisol secretion in obesity through its inferred hyposecretion of hypothalamic CRH might predispose the obese to sleep apnea.

Improvement of anemia with erythropoietin and intravenous iron reduces sleep-related breathing disorders and improves daytime sleepiness in anemic patients with congestive heart failure

BACKGROUND

Central sleep apnea (CSA) (with or without Cheyne-Stokes breathing) or obstructive sleep apnea (OSA) are common in congestive heart failure (CHF). Correction of anemia may improve CHF. We hypothesized that correction of anemia might also improve sleep-related breathing disorders (SRBDs) in CHF.

METHODS

Thirty-eight patients with CHF and anemia (hemoglobin level < 12 g/dL) were treated with erythropoietin and intravenous iron to a target hemoglobin level of 13 g/dL. Home sleep recordings were done before and after 3 months of treatment.

RESULTS

Thirty-seven patients had SRBD (Apnea Hypopnea Index [AHI] of > or = 10). Hemoglobin level increased from 10.4 +/- 0.8 to 12.3 +/- 1.2 g/dL (P < .001). Total AHI values decreased from 35.9 +/- 12.2 to 24.9 +/- 12.2 (P < .001). The AHI of CSA, OSA and Cheyne-Stokes breathing decreased from 26.5 +/- 14.6 to 18.6 +/- 7.7, from 9.4 +/- 10.9 to 6.9 +/- 9.8, and from 13.1 +/- 16.4 to 9.0 +/- 12.2, respectively (all P < .05). Sleep minimal oxygen saturation (SaO2) increased from 62% +/- 12% to 71% +/- 11%; Epworth Sleepiness Scale score improved from 9.4 +/- 6.2 to 6.0 +/- 5.0 and New York Heart Association class improved from 2.9 +/- 0.4 to 1.7 +/- 0.7, all P < .001. Hemoglobin level improvement correlated with improvement in OSA+CSA, CSA, minimal SaO2, Epworth Sleepiness Scale score, and New York Heart Association class (all P < .001).

CONCLUSION

Improvement of anemia in CHF is associated with a reduction in SRBD and an improvement in daytime sleepiness.

Sleep apnea is induced by a high-fat diet and reversed and prevented by metformin in non-obese rats

OBJECTIVE

We assessed the relationship between a high-fat (HF) diet and central apnea during rapid eye movement and non-rapid eye movement sleep stages by recording ventilatory parameters in 28 non-obese rats in which insulin resistance had been induced by an HF diet. We also studied whether metformin (an anti-hyperglycemic drug frequently used to treat insulin resistance) could reverse sleep apnea or prevent its occurrence in this experimental paradigm.

RESEARCH METHODS AND PROCEDURES

Rats were fed with a standard diet (10 rats), an HF diet (8 rats), or an HF diet concomitantly with metformin treatment (10 rats). Each animal was instrumented for electroencephalographic and electromyographic recording. After 3 weeks, ventilatory parameters during sleep were recorded with a body plethysmograph. All rats were treated with metformin for 1 week, after which time the ventilatory measurements were measured again.

RESULTS

Our results showed that the three groups of animals did not differ in terms of body growth over the entire experimental period. The HF diet did not modify sleep structure or minute ventilation in the different sleep stages. A great increase (+266 +/- 48%) in central apnea frequency was observed in insulin-resistant rats. This was explained by an increase in both post-sigh (+195 +/- 35%) and spontaneous apnea (+437 +/- 65%) in the different sleep stages. These increases were suppressed by metformin treatment.

DISCUSSION

Insulin resistance induced by the HF diet could be the promoter of sleep apnea in non-obese rats. Metformin is an efficient curative and preventive treatment for sleep apnea, suggesting that insulin resistance modifies the ventilatory drive independently of obesity.

Does beta-blocker treatment influence central sleep apnoea?

Chronic severe heart failure is frequently associated with disturbances in the central control of breathing. During wakefulness, central breathing disorders could be ameliorated with beta-blocker treatment, but nothing is known about the effects of beta-blockers on the control of breathing during sleep. This study intends to determinate the prevalence and severity of nocturnal apnoeas and hypopnoeas in heart failure patients treated with or without metoprolol or carvedilol. Fifty consecutive patients with dilated cardiomyopathy in NYHA class II-IV with a left ventricular ejection fraction (LVEF) of 35% or below were studied with full polysomnography over one night. The mean Apnoea-Hypopnoea Index of beta-blocker free patients was 19.8+/-14.2 versus 7.4+/-8.5 (p<0.05) and 8.7+/-8.1 (p<0.05) in patients treated with metoprolol or carvedilol, respectively. The arousal index, sleep quality, and daytime sleepiness were improved in similar magnitude.

CONCLUSION

Long-term treatment of patients with advanced chronic heart failure with sufficient doses of metoprolol or carvedilol is associated with a lower prevalence and severity of central sleep apnoea (CSA).

Effects of progesterone on sleep: a possible pharmacological treatment for sleep-breathing disorders?

Progesterone is present in a wide spectrum of biological activity within a variety of tissues. This hormone is also known to affect reproduction, sleep quality, respiration, mood, appetite, learning, memory and sexual activity. Progesterone exerts a sleep induction or hypnotic effect and is a potent respiratory stimulant that has been associated to a decrease in the number of central and obstructive sleep apnea episodes in men. The literature also contains a substantial amount of data on the effect of apnea in women with obesity-hypoventilation during menopause. This review attempts to outline the specific role of progesterone in normal sleep and breathing as well as its possible therapeutic effects in the treatment of sleep-disordered breathing.

Sleep-related breathing disorders in prepubertal children with Prader-Willi syndrome and effects of growth hormone treatment

CONTEXT

Recently, several cases of sudden death in GH-treated and non-GH-treated, mainly young Prader-Willi syndrome (PWS), patients were reported. GH treatment in PWS results in a remarkable growth response and an improvement of body composition and muscle strength. Data concerning effects on respiratory parameters, are however, limited.

OBJECTIVE

The objective of the study was to evaluate effects of GH on respiratory parameters in prepubertal PWS children.

DESIGN

Polysomnography was performed before GH in 53 children and repeated after 6 months of GH treatment in 35 of them.

PATIENTS

Fifty-three prepubertal PWS children (30 boys), with median (interquartile range) age of 5.4 (2.1-7.2) yr and body mass index of +1.0 sd score (-0.1-1.7).

INTERVENTION

Intervention included treatment with GH 1 mg/m2.d.

RESULTS

Apnea hypopnea index (AHI) was 5.1 per hour (2.8-8.7) (normal 0-1 per hour). Of these, 2.8 per hour (1.5-5.4) were central apneas and the rest mainly hypopneas. Duration of apneas was 15.0 sec (13.0-28.0). AHI did not correlate with age and body mass index, but central apneas decreased with age (r = -0.34, P = 0.01). During 6 months of GH treatment, AHI did not significantly change from 4.8 (2.6-7.9) at baseline to 4.0 (2.7-6.2; P = 0.36). One patient died unexpectedly during a mild upper respiratory tract infection, although he had a nearly normal polysomnography.

CONCLUSIONS

PWS children have a high AHI, mainly due to central apneas. Six months of GH treatment does not aggravate the sleep-related breathing disorders in young PWS children. Our study also shows that monitoring during upper respiratory tract infection in PWS children should be considered.