Thalamocortical dynamics during Rapid Eye Movement Sleep in the Mouse Somatosensory Pathway.

Rapid eye movement sleep (REM), also referred to as paradoxical sleep for the striking resemblance of its electroencephalogram (EEG) to the one observed in wakefulness, is characterized by the occurrence of transient events such as limb twitches or facial and rapid eye movements. Here, we investigated the local activity of the primary somatosensory or barrel cortex (S1) in naturally sleeping head-fixed male mice during REM. Through local field potential (LFP) recordings, we uncovered local appearances of spindle waves in the barrel cortex during REM concomitant with strong delta power, challenging the view of a wakefulness-like activity in REM. We further performed extra- and intracellular recordings of thalamic cells in head-fixed mice. Our data show high frequency thalamic bursts of spikes and subthreshold spindle oscillations in about half of the neurons of the ventral posterior medial nucleus which further confirmed the thalamic origin of local cortical spindles in S1 in REM. Cortical spindle oscillations were suppressed, while thalamus spike firing increased, associated with rapid mouse whisker movements and S1 cortical activity transitioned to an activated state. During REM, sensory thalamus and barrel cortex therefore alternate between high (wake-like) and low (non-REM sleep-like) activation states, potentially providing a neuronal substrate for mnemonic processes occurring during this paradoxical sleep stage.Significance Statement Mammalian sleep includes slow wave sleep, or non-rapid eye movement sleep (NREM), and the subsequent REM sleep (REM). At the EEG global level, cortical activity during REM sleep has long been believed to share some similarities with awake cortical activity. The well-defined mouse whisker system offers the unique opportunity to precisely investigate cortical and thalamic dynamics during wakefulness and REM. Combining local field potential (LFP) recordings in primary somatosensory cortex, with single-unit neuronal recordings in its associated thalamic nucleus, we found that during REM, sensory thalamus and barrel cortex alternate between high (wake-like) and low (non-REM sleep-like) activation states, potentially providing a neuronal substrate for mnemonic processes occurring during this paradoxical sleep stage.

Investigation of anti-neuronal antibodies and disparity in central hypersomnias.

STUDY OBJECTIVES: Microbial antigens can elicit an immune response leading to the production of autoantibodies cross-reacting with autoantigens. Still, their clinical significance in human sera in the context of brain diseases is unclear. Therefore, assessment of natural autoantibodies reacting with their neuropeptides may elucidate the autoimmune etiology of central hypersomnias. The study aims to determine whether serum autoantibody levels differ in patients with different types of central hypersomnias (narcolepsy type 1 and 2, NT1 and NT2; idiopathic hypersomnia, IH) and healthy controls and if the differences could suggest the participation of autoantibodies in disease pathogenesis. METHODS: Sera from 91 patients with NT1, 27 with NT2, 46 with IH, and 50 healthy controls were examined for autoantibodies against assorted neuropeptides. Participants were screened using questionnaires related to sleep disorders, quality of life, and mental health conditions. In addition, serum biochemical parameters and biomarkers of microbial penetration through the intestinal wall were determined. RESULTS: A higher prevalence of autoantibodies against neuropeptides was observed only for alpha-melanocytes-stimulating hormone (α-MSH) and neuropeptide glutamic acid-isoleucine (NEI), which differed slightly among diagnoses. Patients with both types of narcolepsy exhibited signs of microbial translocation through the gut barrier. According to the questionnaires, patients diagnosed with NT2 or IH had subjectively worse life quality than patients with NT1. Patients displayed significantly lower levels of bilirubin and creatinine and slightly higher alkaline phosphatase values than healthy controls. CONCLUSIONS: Overall, serum anti-neuronal antibodies prevalence is rare, suggesting that their participation in the pathophysiology of concerned sleep disorders is insignificant. Moreover, their levels vary slightly between diagnoses indicating no major diagnostic significance.

Guardians of Rest? Investigating the gut microbiota in central hypersomnolence disorders.

In recent years, there has been an increased interest in elucidating the influence of the gut microbiota on sleep physiology. The gut microbiota affects the central nervous system by modulating neuronal pathways through the neuroendocrine and immune system, the hypothalamus-pituitary-adrenal axis, and various metabolic pathways. The gut microbiota can also influence circadian rhythms. In this study, we observed the gut microbiota composition of patients suffering from narcolepsy type 1, narcolepsy type 2, and idiopathic hypersomnia. We did not observe any changes in the alpha diversity of the gut microbiota among patient groups and healthy controls. We observed changes in beta diversity in accordance with Jaccard dissimilarities between the control group and groups of patients suffering from narcolepsy type 1 and idiopathic hypersomnia. Our results indicate that both these patient groups differ from controls relative to the presence of rare bacterial taxa. However, after adjustment for various confounding factors such as BMI, age, and gender, there were no statistical differences among the groups. This indicates that the divergence in beta diversity in the narcolepsy type 1 and idiopathic hypersomnia groups did not arise due to sleep disturbances. This study implies that using metabolomics and proteomics approaches to study the role of microbiota in sleep disorders might prove beneficial.

Sleep disorders after COVID-19 in Czech population: Post-lockdown national online survey.

Objective: This study aimed to determine the frequency, type, and correlates of a broad spectrum of sleep disorders in adults with COVID-19 up to 32 months after infection. Methods: We conducted a national online survey (Jun 2021-Dec 2022), gathering information on COVID-19 diagnosis, acute disease course, and the subsequent development of sleep disorders from 1507 respondents (mean age 44.5 ± 13.1 years, 64.1% women). Results: 81.3% (1223) reported at least one sleep difficulty that either worsened or first appeared with COVID-19. Females reported a higher number of symptoms (2.03 ± 1.44 versus 1.72 ± 1.43 in men, p < 0.0001). Most common were insomnia symptoms (59.4%), followed by night sweats (38.4%), hypersomnolence (33.3%), vivid dreams or nightmares (26.4%), restless leg syndrome (RLS) (22.8%), and sleep-related breathing disorders (11.1%). All symptoms were associated with a more severe acute disease. A mild decreasing trend in the persistence of sleep symptoms with a longer latency since infection was observed, with 66.7% reporting at least half of their symptoms present at 3-5 months after acute infection, compared to 64.9% at 6-8 months, and 62.4% at 9-11 months (p = 0.0427). However, among those after 12 or more months, over half of the symptoms persisted in 69.5%. The frequency of vivid dreams and nightmares increased in association with COVID-19 in 32.9% (p < 0.001). 9.4% (141) reported new-onset or increased parasomnic manifestations after the infection. Conclusions: Our research shows that sleep disturbances are a common and persistent manifestation of COVID-19 that affects a large proportion of the population and deserves careful monitoring.

Metformin improves cancer immunotherapy by directly rescuing tumor-infiltrating CD8 T lymphocytes from hypoxia-induced immunosuppression.

BACKGROUND: Despite their revolutionary success in cancer treatment over the last decades, immunotherapies encounter limitations in certain tumor types and patients. The efficacy of immunotherapies depends on tumor antigen-specific CD8 T-cell viability and functionality within the immunosuppressive tumor microenvironment, where oxygen levels are often low. Hypoxia can reduce CD8 T-cell fitness in several ways and CD8 T cells are mostly excluded from hypoxic tumor regions. Given the challenges to achieve durable reduction of hypoxia in the clinic, ameliorating CD8 T-cell survival and effector function in hypoxic condition could improve tumor response to immunotherapies. METHODS: Activated CD8 T cells were exposed to hypoxia and metformin and analyzed by fluorescence-activated cell sorting for cell proliferation, apoptosis and phenotype. In vivo, metformin was administered to mice bearing hypoxic tumors and receiving either adoptive cell therapy with tumor-specific CD8 T cells, or immune checkpoint inhibitors; tumor growth was followed over time and CD8 T-cell infiltration, survival and localization in normoxic or hypoxic tumor regions were assessed by flow cytometry and immunofluorescence. Tumor oxygenation and hypoxia were measured by electron paramagnetic resonance and pimonidazole staining, respectively. RESULTS: We found that the antidiabetic drug metformin directly improved CD8 T-cell fitness in hypoxia, both in vitro and in vivo. Metformin rescued murine and human CD8 T cells from hypoxia-induced apoptosis and increased their proliferation and cytokine production, while blunting the upregulation of programmed cell death protein 1 and lymphocyte-activation gene 3. This appeared to result from a reduced production of reactive oxygen species, due to the inhibition of mitochondrial complex I. Differently from what others reported, metformin did not reduce tumor hypoxia, but rather increased CD8 T-cell infiltration and survival in hypoxic tumor areas, and synergized with cyclophosphamide to enhance tumor response to adoptive cell therapy or immune checkpoint blockade in different tumor models. CONCLUSIONS: This study describes a novel mechanism of action of metformin and presents a promising strategy to achieve immune rejection in hypoxic and immunosuppressive tumors, which would otherwise be resistant to immunotherapy.

Parasomnias in Pregnancy.

OBJECTIVES: Pregnancy is often associated with reduced sleep quality and an increase in sleep disorders, such as restless leg syndrome, obstructive sleep apnea, and insomnia. There are few studies investigating the prevalence of parasomnias in pregnancy, although they may be expected to be a significant problem, as disturbed sleep in this time period in addition to these sleep disorders may trigger parasomnia episodes. METHODS: We conducted a survey using an online questionnaire focusing on a comparison of the prevalence of parasomnias in three time periods: 3 months before pregnancy, during pregnancy, and 3 months after delivery. We also inquired about psychiatric and neurological comorbidities, current anxiety and depression symptoms, and pregnancy complications. RESULTS: A total of 325 women (mean age 30.3 ± 5.3 years) participated in the online survey. The overall number of reported parasomnias increased during pregnancy compared to the 3 months before pregnancy (p < 0.001) and decreased after childbirth (p < 0.001). Specifically, we found a significant increase in sleepwalking (p = 0.02) and night terrors (p < 0.001), as well as in vivid dreams (p < 0.001) and nightmares (p < 0.001) during pregnancy. A similar significant increase during pregnancy was reported for head explosion (p < 0.011). In contrast, the number of episodes of sleep paralysis increased after delivery (p = 0.008). At the individual level, an increase in the severity/frequency of individual parasomnia episodes was also observed during pregnancy. Participants whose vivid dreams/nightmares persisted after delivery had higher BDI-II and STAI-T scores. Our data also suggest a significant impact of migraines and other chronic pain, as well as complications during pregnancy, on the presence of parasomnia episodes in our cohort. CONCLUSIONS: We have shown that the prevalence of parasomnias increases during pregnancy and needs to be targeted, especially by non-pharmacological approaches. At the same time, it is necessary to inquire about psychiatric and neurological comorbidities and keep in mind that more sleep disorders may be experienced by mothers who have medical complications during pregnancy.

Tryptophan 2,3-Dioxygenase Expression Identified in Murine Decidual Stromal Cells Is Not Essential for Feto-Maternal Tolerance.

Indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase (TDO) catalyze the rate-limiting step of tryptophan catabolism along the kynurenine pathway, which has important immuno suppressive properties, particularly in tumor cells and dendritic cells. The prominent expression of IDO1 in the placenta also suggested a role in preventing immune rejection of fetal tissues, and pharmacological inhibition of IDO1 induced abortion of allogeneic fetuses in mice. However, this was later challenged by the lack of rejection of allogeneic fetuses in IDO1-KO mice, suggesting that other mechanisms may compensate for IDO1 deficiency. Here we investigated whether TDO could contribute to feto-maternal tolerance and compensate for IDO1 deficiency in IDO1-KO mice. Expression of TDO mRNA was previously detected in placental tissues. We developed a new chimeric rabbit anti-TDO antibody to confirm TDO expression at the protein level and identify the positive cell type by immunohistochemistry in murine placenta. We observed massive TDO expression in decidual stromal cells, starting at day E3.5, peaking at day E6.5 then declining rapidly while remaining detectable until gestation end. IDO1 was also induced in decidual stromal cells, but only at a later stage of gestation when TDO expression declined. To determine whether TDO contributed to feto-maternal tolerance, we mated TDO-KO and double IDO1-TDO-KO females with allogeneic males. However, we did not observe reduced fertility. These results suggest that, despite its expression in decidual stromal cells, TDO is not a dominant mechanism of feto-maternal tolerance able to compensate for the absence of IDO1. Redundant additional mechanisms of immunosuppression likely take over in these KO mice. The massive expression of TDO during decidualization might suggest a role of TDO in angiogenesis or vessel tonicity, as previously described for IDO1.

Tryptophan 2,3-Dioxygenase Expression Identified in Human Hepatocellular Carcinoma Cells and in Intratumoral Pericytes of Most Cancers.

Tryptophan catabolism is used by tumors to resist immune attack. It can be catalyzed by indoleamine 2,3-dioxygenase (IDO1) and tryptophan 2,3-dioxygenase (TDO). IDO1 is frequently expressed in tumors and has been widely studied as a potential therapeutic target to reduce resistance to cancer immunotherapy. In contrast, TDO expression in tumors is not well characterized. Several human tumor cell lines constitutively express enzymatically active TDO. In human tumor samples, TDO expression has previously been detected by transcriptomics, but the lack of validated antibodies has precluded detection of the TDO protein and identification of TDO-expressing cells. Here, we developed novel TDO-specific monoclonal antibodies and confirmed by immunohistochemistry the expression of TDO in the majority of human cancers. In all hepatocarcinomas (10/10), TDO was expressed by most tumor cells. Some glioblastomas (10/39) and kidney carcinomas (1/10) also expressed TDO in tumor cells themselves but only in focal tumor areas. In addition, all cancers tested contained foci of nontumoral TDO-expressing cells, which were identified as pericytes by their expression of PDGFRß and their location in vascular structures. These TDO-expressing pericytes belonged to morphologically abnormal tumor vessels and were found in high-grade tumors in the vicinity of necrotic or hemorrhagic areas, which were characterized by neoangiogenesis. We observed similar TDO-expressing pericytes in inflammatory pulmonary lesions containing granulation tissue, and in chorionic villi, two tissue types that also feature neoangiogenesis. Our results confirm TDO as a relevant immunotherapeutic target in hepatocellular carcinoma and suggest a proangiogenic role of TDO in other cancer types.See article by Schramme et al., p. 32.

Effect of repeated therapeutic horse riding sessions on the trunk movement of the rider.

OBJECTIVE: To assess the rider's movement during walking the horse in repeated therapeutic horse riding sessions and to determine the relationship between movements of the horse's back and the rider's trunk. METHOD: A total of 12 healthy females (age: 23.3±2.8 years; height: 167.3±4.2 cm; weight: 59.2±5.3 kg) participated in 10 therapeutic horse riding sessions. Two English Thoroughbreds with similar body constitution (aged 19 and 14 years) were used in the experiment. Nine markers were placed on the rider's body and the horse's back, and four video cameras with a 25 Hz frequency were used. Collected data were processed with APAS software. RESULTS: The mediolateral displacements of C7, Th12, and L5 were gradually decreasing in each of the first three sessions. Statistically significant differences (p<0.05) were found between individual sessions in the displacement of C7, Th12 and L5 in the mediolateral and vertical directions as well as in the shoulder and pelvic lateral tilt and rotation. These differences did not show any general tendencies regarding the riders' increasing experiences with riding. The relationships between the displacement of C7, Th12, and L5 and the sacral tuber on the horse's back in the vertical direction were statistically significant (p<0.01) during all sessions. CONCLUSIONS: The displacement of C7, Th12 and L5 in the mediolateral direction decreased during riding sessions. A significant relationship was found between the vertical movement of the horse's back and the rider's trunk. These relationships differed between the horses.

An assessment of the pressure distribution exerted by a rider on the back of a horse during hippotherapy.

Hippotherapy employs locomotion impulses that are emitted from the back of a horse while the horse is walking. These impulses stimulate the rider's postural reflex mechanisms, resulting in training of balance and coordination. The aim of the present study was to assess the changes in magnitude and distribution of the contact pressure between the rider and the horse during a series of hippotherapy lessons. The monitored group, consisting of four healthy women (mean age 22.75 years, mean body weight 59.75 kg, mean height 167.25 cm) without any previous horse riding experience, received five 20 minute-lessons lessons in a three-week period. Hippotherapy was given on a 15-year-old thoroughbred mare. An elastic pad (Novel Pliance System, 30 Hz, 224 sensors) was used for pressure magnitude evaluation. The maximum pressure value was increased (p<.05) in the event of a second measurement (5th lesson). The pressure exerted on the rider upon contact of the rear limbs was higher than upon contact of the front limbs (p<.01). The size of the center of pressure (COP) deviations in the anteroposterior direction reduced (p<.05) with the number of lessons received. With the growing experience of the participant, an increase in pressure occurred on contact of her body and the horse's back as well as in the stability of the COP movement.