BACKGROUND: Obstructive sleep apnea (OSA) is one of the risk factors for diabetes mellitus type 2 (DM2). As OSA is associated with the disruption of the circadian rhythm, it affects circadian clock proteins, including neuronal PAS domain protein 2 (NPAS2) and nuclear receptor subfamily 1 group D member 1 (Rev-Erb-α). These proteins have been shown to be related to metabolic abnormalities, i.a., insulin resistance.
OBJECTIVE: The present pilot study aimed to investigate the NPAS2 and Rev-Erb-α protein serum levels in the groups of patients with severe OSA and severe OSA+DM2 in comparison with healthy controls, taking into account correlations with polysomnography (PSG) parameters (e.g., oxygen saturation (SpO2) variables).
METHODS: A total of 40 participants were included in the study. They were split into 3 groups as follows: the OSA group (n = 17; apnea-hypopnea index (AHI) >30, no DM2); the OSA+DM2 group (n = 7; AHI > 30 and DM2); and the control group (n = 16; AHI < 5, no DM2). All participants underwent a nocturnal PSG examination and had their blood collected the following morning. The serum levels of NPAS2 and Rev-Erb-α proteins were assessed using the enzyme-linked immunosorbent assay (ELISA).
RESULTS: The mean NPAS2 protein level was significantly lower in the OSA group as compared to healthy individuals (p = 0.017). Additionally, the OSA group presented with lower NPAS2 protein levels as compared to the OSA+DM2 group, but only a tendency was observed (p = 0.094). No differences in the Rev-Erb-α protein concentration were noticed. Furthermore, a negative correlation between AHI during rapid eye movement (REM) sleep and the NPAS2 protein serum level was observed (r = -0.478; p = 0.002).
CONCLUSIONS: Serum NPAS2 protein might be involved in metabolic dysregulation present among OSA patients, while the mechanism itself may be associated with REM sleep.

For several decades, it has been known that a substantial number of genes within human DNA exhibit overlap; however, the biological and evolutionary significance of these overlaps remain poorly understood. This study focused on investigating specific instances of overlap where the overlapping DNA region encompasses the coding DNA sequences (CDSs) of protein-coding genes. The results revealed that proteins encoded by overlapping CDSs exhibit greater disorder than those from nonoverlapping CDSs. Additionally, these DNA regions were identified as GC-rich. This could be partially attributed to the absence of stop codons from two distinct reading frames rather than one. Furthermore, these regions were found to harbour fewer single-nucleotide polymorphism (SNP) sites, possibly due to constraints arising from the overlapping state where mutations could affect two genes simultaneously.While elucidating these properties, the NR1D1-THRA gene pair emerged as an exceptional case with highly structured proteins and a distinctly conserved sequence across eutherian mammals. Both NR1D1 and THRA are nuclear receptors lacking a ligand-binding domain at their C-terminus, which is the region where these gene pairs overlap. The NR1D1 gene is involved in the regulation of circadian rhythm, while the THRA gene encodes a thyroid hormone receptor, and both play crucial roles in various physiological processes. This study suggests that, in addition to their well-established functions, the specifically overlapping CDS regions of these genes may encode protein segments with additional, yet undiscovered, biological roles.

OBJECTIVE: To detect premature gluco-metabolic defects among night shift workers with disturbances in circadian rhythms.
METHODS: We performed a hypothesis-generating, cross-sectional analysis of anthropometric, metabolic, lipid, and inflammation parameters, comparing active (a-NSW, n = 111) and former (f-NSW, n = 98) rotating night shift workers with diurnal workers (controls, n = 69). All participants were hospital nurses. We also evaluated the Pittsburgh Sleep Quality Index (PSQI) and assessed expression of transcription factors REV-ERBα and BMAL1 in peripheral blood mononuclear cells (PBMCs), as indicators of the molecular clock.
RESULTS: Both a-NSW and f-NSW participants had significantly higher glycated hemoglobin (HbA1c) and white blood cell counts (WBC) (p < 0.001 for both), PSQI global score (p = 0.001) and diastolic blood pressure levels (p = 0.024) compared with controls. Expression of REV-ERBα/BMAL1 RNA in PBMC was significantly higher in a-NSW (p = 0.05) than in f-NSW or control participants. Multivariate regression analysis showed that working status and PSQI were independent determinants of higher HbA1c levels (p < 0.001).
CONCLUSIONS: We demonstrated that young, healthy night shift workers show subclinical abnormalities in HbA1c and changes in peripheral clock gene expression.

On-pump cardiac surgery provokes a predictable perioperative myocardial ischaemia-reperfusion injury which is associated with poor clinical outcomes. We determined the occurrence of time-of-the-day variation in perioperative myocardial injury in patients undergoing aortic valve replacement and its molecular mechanisms.
We studied the incidence of major adverse cardiac events in a prospective observational single-centre cohort study of patients with severe aortic stenosis and preserved left ventricular ejection fraction (>50%) who were referred to our cardiovascular surgery department at Lille University Hospital (Lille, France) for aortic valve replacement and underwent surgery in the morning or afternoon. Patients were matched into pairs by propensity score. We also did a randomised study, in which we evaluated perioperative myocardial injury and myocardial samples of patients randomly assigned (1:1) via permuted block randomisation (block size of eight) to undergo isolated aortic valve replacement surgery either in the morning or afternoon. We also evaluated human and rodent myocardium in ex-vivo hypoxia-reoxygenation models and did a transcriptomic analysis in myocardial samples from the randomised patients to identify the signalling pathway(s) involved. The primary objective of the study was to assess whether myocardial tolerance of ischaemia-reperfusion differed depending on the timing of aortic valve replacement surgery (morning vs afternoon), as measured by the occurrence of major adverse cardiovascular events (cardiovascular death, myocardial infarction, and admission to hospital for acute heart failure). The randomised study is registered with ClinicalTrials.gov, number NCT02812901.
In the cohort study (n=596 patients in matched pairs who underwent either morning surgery [n=298] or afternoon surgery [n=298]), during the 500 days following aortic valve replacement, the incidence of major adverse cardiac events was lower in the afternoon surgery group than in the morning group: hazard ratio 0·50 (95% CI 0·32-0·77; p=0·0021). In the randomised study, 88 patients were randomly assigned to undergo surgery in the morning (n=44) or afternoon (n=44); perioperative myocardial injury assessed with the geometric mean of perioperative cardiac troponin T release was significantly lower in the afternoon group than in the morning group (estimated ratio of geometric means for afternoon to morning of 0·79 [95% CI 0·68-0·93; p=0·0045]). Ex-vivo analysis of human myocardium revealed an intrinsic morning-afternoon variation in hypoxia-reoxygenation tolerance, concomitant with transcriptional alterations in circadian gene expression with the nuclear receptor Rev-Erbα being highest in the morning. In a mouse Langendorff model of hypoxia-reoxygenation myocardial injury, Rev-Erbα gene deletion or antagonist treatment reduced injury at the time of sleep-to-wake transition, through an increase in the expression of the ischaemia-reperfusion injury modulator CDKN1a/p21.
Perioperative myocardial injury is transcriptionally orchestrated by the circadian clock in patients undergoing aortic valve replacement, and Rev-Erbα antagonism seems to be a pharmacological strategy for cardioprotection. Afternoon surgery might provide perioperative myocardial protection and lead to improved patient outcomes compared with morning surgery.
Fondation de France, Fédération Française de Cardiologie, EU-FP7-Eurhythdia, Agence Nationale pour la Recherche ANR-10-LABX-46, and CPER-Centre Transdisciplinaire de Recherche sur la Longévité.

OBJECTIVE: The aim of our study was to investigate the association between REV-ERBalpha gene (NR1D1) single nucleotide polymorphisms (SNPs) and bipolar disorder (BP) in a case-control sample of Sardinian ancestry and evaluate its effect on age at onset (AAO) of BP.
METHODS: We genotyped SNPs rs12941497 (SNP1) and rs939347 (SNP2), located, respectively, in the first intron and in the 5\'UTR region of the gene, in a sample comprised of 300 bipolar patients and 300 healthy controls of Sardinian ancestry. We also studied AAO by means of admixture analysis, obtaining a cutoff point of age 22 and then carrying out association analysis between the two AAO groups.
RESULTS: In the case-control comparison, single marker analysis showed no association for any of the SNPs tested. Haplotype analysis showed a nominally significant association for two haplotypes of SNPs 1-2. Comparing the early- and later-onset groups, nominal association was found for SNP1. Haplotype analysis showed that one haplotype was nominally associated with the later-onset group.
CONCLUSIONS: Our results, indicating a nominal association of the REV-ERBalpha gene with BP, suggest a possible role of REV-ERBalpha in the pathogenesis of BP. Further investigation of larger independent samples and different populations is warranted.