Hemodialysis-induced chronodisruption and chronotype distribution in patients with chronic kidney disease.

Changes in circadian rhythms have been observed in patients with chronic kidney disease (CKD), and evidence suggests that these changes can have a negative impact on health. This study aimed to investigate the existence of hemodialysis-induced chronodisruption, the chronotype distribution, and their association with sleep quality and quality of life (QoL). This was a cross-sectional study that enrolled 165 patients (mean age: 51.1 ± 12.5 y, 60.6% male) undergoing hemodialysis from three local units. The following instruments were used: the Morning-Eveningness Questionnaire (MEQ); a modified version of the Munich Chronotype Questionnaire (MCQT) to estimate hemodialysis-induced chronodisruption (HIC); the Kidney Disease QoL Short Form (KDQOL-SF); the Epworth Sleepiness Scale (ESS); the Pittsburgh Sleep Quality Index (PSQI) and the 10-Cognitive Screener (10-CS). HIC was present in 40.6% of CKD patients. Morning chronotype was prevalent in CKD patients (69%) compared to evening-type (17.1%) and significantly different from a paired sample from the general population (p < 0.001). HIC and chronotype were associated with different domains of QoL but not with sleep quality. This study suggests that there is a HIC and that morning chronotype is associated with CKD patients undergoing hemodialysis, with implications for QoL.

Practice recommendations for the role of physiotherapy in the management of sleep disorders: the 2022 Brazilian Sleep Association Guidelines.

This clinical guideline supported by the Brazilian Sleep Association comprises a brief history of the development of Brazilian sleep physiotherapy, outlines the role of the physiotherapist as part of a sleep health team, and describes the clinical guidelines in respect of the management of some sleep disorders by the physiotherapist (including sleep breathing disorders, i.e., obstructive sleep apnea, central sleep apnea, upper airway resistance syndrome, hypoventilation syndromes and overlap syndrome, and pediatric sleep breathing disorders; sleep bruxism; circadian rhythms disturbances; insomnia; and Willis-Ekbom disease/periodic limb movement disorder. This clinical practice guideline reflects the state of the art at the time of publication and will be reviewed and updated as new information becomes available.

Potential biomarkers of major depression diagnosis and chronicity.

BACKGROUND: Molecular biomarkers are promising tools to be routinely used in clinical psychiatry. Among psychiatric diseases, major depression disorder (MDD) has gotten attention due to its growing prevalence and morbidity. METHODS: We tested some peripheral molecular parameters such as serum mature Brain-Derived Neurotrophic Factor (mBDNF), plasma C-Reactive Protein (CRP), serum cortisol (SC), and the salivary Cortisol Awakening Response (CAR), as well as the Pittsburgh sleep quality inventory (PSQI), as part of a multibiomarker panel for potential use in MDD diagnosis and evaluation of disease's chronicity using regression models, and ROC curve. RESULTS: For diagnosis model, two groups were analyzed: patients in the first episode of major depression (MD: n = 30) and a healthy control (CG: n = 32). None of those diagnosis models tested had greater power than Hamilton Depression Rating Scale-6. For MDD chronicity, a group of patients with treatment-resistant major depression (TRD: n = 28) was tested across the MD group. The best chronicity model (p < 0.05) that discriminated between MD and TRD included four parameters, namely PSQI, CAR, SC, and mBDNF (AUC ROC = 0.99), with 96% of sensitivity and 93% of specificity. CONCLUSION: These results indicate that changes in specific biomarkers (CAR, SC, mBDNF and PSQI) have potential on the evaluation of MDD chronicity, but not for its diagnosis. Therefore, these findings can contribute for further studies aiming the development of a stronger model to be commercially available and used in psychiatry clinical practice.

Pathophysiology of Major Depression by Clinical Stages.

The comprehension of the pathophysiology of the major depressive disorder (MDD) is essential to the strengthening of precision psychiatry. In order to determine the relationship between the pathophysiology of the MDD and its clinical progression, analyzed by severity of the depressive symptoms and sleep quality, we conducted a study assessing different peripheral molecular biomarkers, including the levels of plasma C-reactive protein (CRP), serum mature brain-derived neurotrophic factor (mBDNF), serum cortisol (SC), and salivary cortisol awakening response (CAR), of patients with MDD (n = 58) and a control group of healthy volunteers (n = 62). Patients with the first episode of MDD (n = 30) had significantly higher levels of CAR and SC than controls (n = 32) and similar levels of mBDNF of controls. Patients with treatment-resistant depression (TRD, n = 28) presented significantly lower levels of SC and CAR, and higher levels of mBDNF and CRP than controls (n = 30). An increased severity of depressive symptoms and worse sleep quality were correlated with levels low of SC and CAR, and with high levels of mBDNF. These results point out a strong relationship between the stages clinical of MDD and changes in a range of relevant biological markers. This can assist in the development of precision psychiatry and future research on the biological tests for depression.

La Variabilidad de la Frecuencia Cardíaca (VFC) como medida Objetiva de la Atención Sostenida en el Salón de Clase / The Variability of Heart Rate (HRV) as an Objective Measurement of Sustained Attention in the Classroom

El objetivo que se propone en el presente informe es probar la hipótesis teórica de que el tiempo de atención sostenida en los estudiantes en el salón de clase puede ser medida por la respuesta autonómica de la VFC. 10 sujetos participaron del experimento. La VFC fue observada por medio del análisis de series temporales en segmentos de cinco (5) minutos hasta completar la ventana de observación para medias móviles simples de 60 minutos. Se analizaron las series RR en los dominios de tiempo, de frecuencia e índices no lineares.

The objective proposed in this report is to test the theoretical hypothesis that the time of attention sustained by students in the classroom can be measured by the autonomic response of the VFC. 10 subjects participated in the experiment. HRV was observed by means of the analysis of time series in segments of five (5) minutes until completing the observation window for simple moving averages of 60 minutes. The RR series were analyzed in the time, frequency and non-linear index domains.

PER3 gene regulation of sleep-wake behavior as a function of latitude.

OBJECTIVES: We searched for interactions between PER3 gene VNTR polymorphism, latitude, sleep duration, diurnal sleepiness, and social jetlag. DESIGN: We selected samples from 3 distinct cities along the latitudinal range of Brazil and comprising the same time zone. SETTING: Undergraduate universities located in 3 major cities of Brazil. PARTICIPANTS: A total of 980 undergraduate students: 276 from Maceio (latitude 9°), 358 from Campinas (latitude 22°), and 346 from Porto Alegre (latitude 30°). MEASUREMENTS: PER3 variable number of tandem repeats genotyping, diurnal sleepiness, sleep duration (weekdays and weekend), chronotype, and social jetlag. RESULTS: Latitude is associated with a differential expression of circadian and sleep profiles. We observed a shift toward eveningness with increased latitude and increased social jetlag and diurnal sleepiness at latitude 30°. Moreover, our results suggest that the PER3 variable number of tandem repeats polymorphism has a modulatory effect on these circadian and sleep profiles: the variant PER34/4 is associated with a smaller difference in the sleep duration on weekdays among different latitudes and is associated with longer sleep duration on weekends just at latitude 30°, even when compared to both other genotypes at the same latitude. On the other hand, irrespective of the genotype, volunteers from latitude 30° expressed increased social jetlag and diurnal sleepiness. CONCLUSIONS: The seasonal variation in the light/dark cycle, tied to latitude, together with the tight social time constraints that young adults are subjected to during weekdays, generates differences in the sleep phenotypes. Volunteers with the PER34/4 variant who live farther from the equator have a greater increase in their weekend sleep duration.

Latitudinal cline of chronotype.

The rotation of the Earth around its own axis and around the sun determines the characteristics of the light/dark cycle, the most stable and ancient 24 h temporal cue for all organisms. Due to the tilt in the earth's axis in relation to the plane of the earth's orbit around the sun, sunlight reaches the Earth differentially depending on the latitude. The timing of circadian rhythms varies among individuals of a given population and biological and environmental factors underlie this variability. In the present study, we tested the hypothesis that latitude is associated to the regulation of circadian rhythm in humans. We have studied chronotype profiles across latitudinal cline from around 0° to 32° South in Brazil in a sample of 12,884 volunteers living in the same time zone. The analysis of the results revealed that humans are sensitive to the different sunlight signals tied to differences in latitude, resulting in a morning to evening latitudinal cline of chronotypes towards higher latitudes.

Self-reported discomfort associated with Daylight Saving Time in Brazilian tropical and subtropical zones.

BACKGROUND: Daylight Saving Time (DST) annually moves clocks 1 hour forward, when daytime is longer than night. Previous studies from medium and high latitude locations have pointed to a disruptive effect of DST on human circadian rhythms. Since Brazil is an equatorial country implementing DST, a different relationship between photic and social synchronisers may interfere with DST effects. AIM: To explore the prevalence and duration of self-reported discomfort related to DST among Brazilian residents (latitude 12-33° S, longditude 39-57° W). It was hypothesised that an elevated prevalence of self-reported discomfort would be found in Brazil, due to the pronounced uncoupling between social and geophysical synchronisers. SUBJECTS AND METHODS: In total, 12 467 volunteers completed a web-based, Brazilian version of Horne-Östberg Morningness-Eveningness Questionnaire, provided demographic information, and answered questions related to DST complaints (discomfort, duration of discomfort). RESULTS: Of the total sample, 45.43% reported no discomfort related to DST, with meaningful proportions for all chronotypes. However, eveningness was most associated with discomfort. About one fourth of the total sample reported discomfort over the whole DST period. Gender interaction is largely supported by these results. CONCLUSIONS: DST at low latitude locations may be disruptive for circadian rhythms, since seasonality of sunrise near the equator is negligible or very mild.