Épidémiologie du syndrome des jambes sans repos

Effects of iron-deficient diet on sleep onset and spinal reflexes in a rodent model of Restless Legs Syndrome

Restless Legs Syndrome (RLS) is a common sensorimotor and a sleep disorder that affects 2.5-10% of the European and North American populations. RLS is also often associated with periodic leg movements during sleep (PLMS). Despite ample evidence of genetic contributions, the underlying mechanisms that elicit the sensory and motor symptoms remain unidentified. Clinically, RLS has been correlated with an altered central iron metabolism, particularly in the brain. While several animal models have been developed to determine the outcome of an altered iron homeostasis on brain function, the potential role of an altered iron homeostasis on sleep and sensorimotor circuits has not yet been investigated. Here, we utilize a mouse model to assess the effects of an iron-deficient (ID) but non-anemic state on sleep time and episodes, and sensorimotor reflexes in male and female mice. We found that animals on the ID diet displayed an increased expression of the transferrin receptor in the spinal cord, confirming the results of previous studies that focused only on the impact of ID in the brain. We also demonstrate that the ID diet reduced hematocrit levels compared to controls but not into the anemic range, and that animals on the ID diet exhibited RLS-like symptoms with regard to sleep onset and spinal cord reflex excitability. Interestingly, the effects on the spinal cord were stronger in females than in males, and the ID diet-induced behaviors were rescued by the return of the animals to the control diet. Taken together, these results demonstrate that diet-induced ID changes to CNS function are both inducible and reversible, and that they mimic the sleep and sensorimotor RLS symptoms experienced in the clinic. We therefore propose replacing the commonly used phrase "brain iron deficiency" (BID) hypothesis in the RLS research field with the term "iron deficiency in the central nervous system" (ID-CNS), to include possible effects of altered iron levels on spinal cord function.

Prevalence of sleep disorders in a large French cohort of aircrew members and risk of in-flight sleepiness

BACKGROUND

/objectives: Sleep disorders are a critical issue for flight safety. Previous studies have shown a high prevalence of sleep disorders and excessive sleepiness in the general population and some aircrews. The objectives of this study are to measure the prevalence of excessive daytime sleepiness and sleep disorders in aircrews, and to determine the risk factors of falling asleep during a flight.

METHODS

this is a monocentric study based on questionnaires, including all professional civilian and military aircrews examined in an aeromedical center between January and May 2021. The questionnaire, created for this study, included information about socio-demographic characteristics, aeronautical experience, lifestyle, sleep habits, an Epworth sleepiness scale, and screening tests for chronic insomnia, sleep apnea syndrome and restless legs syndrome.

RESULTS

749 aircrew members were included (86.2% male, 58.9% civilian, 74.1% pilot, mean age 43.4 ± 9.6 years), 45.9% of the population had at least one sleep disorder (chronic insomnia 39.5%, sleep apnea syndrome 10.5%, restless legs syndrome 4.1%), 15.5% had an excessive daytime sleepiness, and 24.6% reported in-flight sleep while on duty. Chronic insomnia, screen use before bedtime, use of sleeping pills, inadequate recovery time after a flight, female gender and civilian status were found as risk factors of in-flight sleep in the multivariate analysis.

CONCLUSION

this study emphasizes the need to improve the screening and prevention of sleep disorders in this particular population.

Traditional Chinese medicine for restless legs syndrome: A study protocol for a network meta-analysis

BACKGROUND

Restless legs syndrome (RLS) is a sensory motor disorder. It mainly manifests as indescribable pain in the lower limbs at night or at rest, and the symptoms are reduced after activity or beating, which seriously affects the patients sleep. Nowadays, a large number of randomized controlled clinical studies have shown that Chinese medicine has the advantages of good curative effect and high safety in the treatment of RLS. However, due to the various treatment methods of Chinese medicine, its relative effectiveness and safety have not been verified. Therefore, this study will use a network meta-analysis method to verify the effectiveness and safety of different types of TCM therapies in the treatment of RLS.

METHODS

Computer retrieval was conducted in PubMed, Cochrane Library, Web of Science, Embase, SinoMed, CNKI, WanFang-database, VIP. The retrieval period was until September 9, 2020, and all randomized controlled trials of TCM treatment of RLS were collected. To avoid omissions, we will manually search relevant references and conference papers. According to the inclusion and exclusion criteria, we conduct quality assessment and risk assessment of all retrieved documents. Methodological quality assessment and risk of bias will be assessed using Cochrane bias risk tool. All data analysis will use Revman5.3, WinBUGS 1.4.3, and Stata14.2 software.

RESULTS

This study will directly or indirectly compare the effectiveness of different interventions on RLS outcome indicators, and rank the effectiveness. The main outcome indicators include total effective rate (total effective rate = rocovery + obvious effective + effective/total number of cases × 100%), International Restless Legs Syndrome Score Scale, secondary outcome indicators include visual analog scale, Pittsburgh sleep quality indicators and adverse events.

CONCLUSION

Provide a basis for evidence-based medicine, and provide a basis for clinical researchers to choose more effective Chinese medicine treatment of RLS.

Differential Dopamine D1 and D3 Receptor Modulation and Expression in the Spinal Cord of Two Mouse Models of Restless Legs Syndrome

Restless Legs Syndrome (RLS) is often and successfully treated with dopamine receptor agonists that target the inhibitory D3 receptor subtype, however there is no clinical evidence of a D3 receptor dysfunction in RLS patients. In contrast, genome-wide association studies in RLS patients have established that a mutation of the MEIS1 gene is associated with an increased risk in developing RLS, but the effect of MEIS1 dysfunction on sensorimotor function remain unknown. Mouse models for a dysfunctional D3 receptor (D3KO) and Meis1 (Meis1KO) were developed independently, and each animal expresses some features associated with RLS in the clinic, but they have not been compared in their responsiveness to treatment options used in the clinic. We here confirm that D3KO and Meis1KO animals show increased locomotor activities, but that only D3KO show an increased sensory excitability to thermal stimuli. Next we compared the effects of dopaminergics and opioids in both animal models, and we assessed D1 and D3 dopamine receptor expression in the spinal cord, the gateway for sensorimotor processing. We found that Meis1KO share most of the tested behavioral properties with their wild type (WT) controls, including the modulation of the thermal pain withdrawal reflex by morphine, L-DOPA and D3 receptor (D3R) agonists and antagonists. However, Meis1KO and D3KO were behaviorally more similar to each other than to WT when tested with D1 receptor (D1R) agonists and antagonists. Subsequent Western blot analyses of D1R and D3R protein expression in the spinal cord revealed a significant increase in D1R but not D3R expression in Meis1KO and D3KO over WT controls. As the D3R is mostly present in the dorsal spinal cord where it has been shown to modulate sensory pathways, while activation of the D1Rs can activate motoneurons in the ventral spinal cord, we speculate that D3KO and Meis1KO represent two complementary animal models for RLS, in which the mechanisms of sensory (D3R-mediated) and motor (D1R-mediated) dysfunctions can be differentially explored.

The prevalence of restless leg syndrome among pregnant Saudi women

Objectives:

Restless legs syndrome (RLS) is common among pregnant women, but it has not been documented in pregnant Saudi Arabian women. The main purpose of this study was to estimate the extent of the prevalence of RLS and identify both the associated factors and the associated risk factors among pregnant Saudi women.

Methods:

A cross-sectional study was conducted among pregnant women visiting obstetric clinics at King Abdulaziz Medical City in Riyadh (KAMC-Riyadh) over the period from June 1 to November 1, 2014. We interviewed the participants and collected demographic data, number of pregnancies, duration of pregnancy, comorbidities, and symptoms of RLS. The diagnosis of RLS is based on the four criteria designated by the International RLS Study Group.

Results:

The total number of participants enrolled was 517, and the mean age was 30.11 ± 5.42 years. The prevalence of RLS was 21.3% (110/517) (95% confidence interval [CI]: 17.83%-25.06%). RLS symptoms were more common among women in the third trimester (24.1%) compared to the second trimester (14.3%) and first trimester (13.6%), P = 0.043. The stepwise multivariate logistic model identified insomnia (odds ratio [OR]: 3.6, 95% CI: 2.167–6.017, P = 0.001), and poor sleep quality (OR: 4.9, 95% CI: 1.473-16.454, P = 0.010) were associated with RLS.

Conclusion:

RLS occurs in two of ten pregnant women visiting obstetric clinics at KAMC-Riyadh and is strongly associated with insomnia and poor sleep quality. Studies are needed to explore the causality of these associations.

Growing pains: twin family study evidence for genetic susceptibility and a genetic relationship with restless legs syndrome

BACKGROUND

Growing pains (GP) is a prevalent familial childhood disorder of unknown aetiology. Familial occurrence of GP, and individual and familial association of GP with restless legs syndrome (RLS) has been reported.

METHODS

We applied a twin family design to search for evidence of genetic susceptibility to GP, and for a genetic relationship between GP and RLS. The parents of 1843 twin pairs aged 3-16 years were administered a questionnaire, which identified 88 pairs with at least one twin individual fulfilling criteria for GP. Standard questionnaires for history of GP and RLS were completed for these twin pairs, their siblings and parents.

RESULTS

Twenty-five of 34 monozygotic (MZ) pairs were concordant for GP, compared with 12 of the 54 dizygotic (DZ) pairs. The casewise concordance was 0.85 and 0.36 for MZ and DZ pairs, respectively (p < 0.001). The lifetime GP prevalence for relatives of twins with GP was 51% for non-twin siblings, 47% for parents. Twenty-three percent of twin individuals with GP met RLS criteria compared with 8% of twin individuals without GP (p = 0.03). Of the twins with GP concordance, 19% met RLS criteria compared with 2% of twins with GP discordance (p = 0.01). In two MZ pairs, one had GP and the other RLS. The lifetime prevalence of RLS was 40% for mothers, and 24% for fathers and 18% for non-twin siblings.

CONCLUSION

This first twin family study of GP provides evidence for a genetic aetiology and for a genetic relationship to RLS.