:  The human pineal gland is a neuroendocrine transducer that forms an integral part of the brain. Through the nocturnally elevated synthesis and release of the neurohormone melatonin, the pineal gland encodes and disseminates information on circadian time, thus coupling the outside world to the biochemical and physiological internal demands of the body. Approaches to better understand molecular details behind the rhythmic signalling in the human pineal gland are limited but implicitly warranted, as human chronobiological dysfunctions are often associated with alterations in melatonin synthesis. Current knowledge on melatonin synthesis in the human pineal gland is based on minimally invasive analyses, and by the comparison of signalling events between different vertebrate species, with emphasis put on data acquired in sheep and other primates. Together with investigations using autoptic pineal tissue, a remnant silhouette of premortem dynamics within the hormone’s biosynthesis pathway can be constructed. The detected biochemical scenario behind the generation of dynamics in melatonin synthesis positions the human pineal gland surprisingly isolated. In this neuroendocrine brain structure, protein‐protein interactions and nucleo‐cytoplasmic protein shuttling indicate furthermore a novel twist in the molecular dynamics in the cells of this neuroendocrine brain structure. These findings have to be seen in the light that an impaired melatonin synthesis is observed in elderly and/or demented patients, in individuals affected by Alzheimer’s disease, Smith–Magenis syndrome, autism spectrum disorder and sleep phase disorders. Already, recent advances in understanding signalling dynamics in the human pineal gland have significantly helped to counteract chronobiological dysfunctions through a proper restoration of the nocturnal melatonin surge.

Purpose: Although patients with SARS-CoV-2 infection have several risk factors for ventilator-associated lower respiratory tract infections (VA-LRTI), the reported incidence of hospital-acquired infections is low. We aimed to determine the relationship between SARS-CoV-2 pneumonia, as compared to influenza pneumonia or no viral infection, and the incidence of VA-LRTI.Methods: Multicenter retrospective European cohort performed in 36 ICUs. All adult patients receiving invasive mechanical ventilation > 48 h were eligible if they had: SARS-CoV-2 pneumonia, influenza pneumonia, or no viral infection at ICU admission. VA-LRTI, including ventilator-associated tracheobronchitis (VAT) and ventilator-associated pneumonia (VAP), were diagnosed using clinical, radiological and quantitative microbiological criteria. All VA-LRTI were prospectively identified, and chest-X rays were analyzed by at least two physicians. Cumulative incidence of first episodes of VA-LRTI was estimated using the Kalbfleisch and Prentice method, and compared using Fine-and Gray models.Results: 1576 patients were included (568 in SARS-CoV-2, 482 in influenza, and 526 in no viral infection groups). VA-LRTI incidence was significantly higher in SARS-CoV-2 patients (287, 50.5%), as compared to influenza patients (146, 30.3%, adjusted sub hazard ratio (sHR) 1.60 (95% confidence interval (CI) 1.26 to 2.04)) or patients with no viral infection (133, 25.3%, adjusted sHR 1.7 (95% CI 1.2 to 2.39)). Gram-negative bacilli were responsible for a large proportion (82% to 89.7%) of VA-LRTI, mainly Pseudomonas aeruginosa, Enterobacter spp., and Klebsiella spp.

In species ranging from flies to mammals, parameters of memory processing, like acquisition, consolidation, and retrieval are clearly molded by time of day. However, mechanisms that regulate and adapt these temporal differences are elusive, with an involvement of clock genes and their protein products suggestive. Therefore, we analyzed initially in mouse hippocampus the daytime-dependent dynamics of parameters, known to be important for proper memory formation, like phosphorylation of the "memory molecule" cyclic adenosine monophosphate (cAMP) responsive element binding protein (CREB) and chromatin remodeling. Next, in an effort to characterize the mechanistic role of clock genes within hippocampal molecular dynamics, we compared the results obtained from wildtype (WT) -mice and mice deficient for the archetypical clock gene Period1 (Per1(-/-) -mice). We detected that the circadian rhythm of CREB phosphorylation in the hippocampus of WT mice disappeared completely in mice lacking Per1. Furthermore, we found that the here for the first time described profound endogenous day/night rhythms in histone modifications in the hippocampus of WT-mice are markedly perturbed in Per1(-/-) -mice. Concomitantly, both, in vivo recorded LTP, a cellular correlate for long-term memory, and hippocampal gene expression were significantly altered in the absence of Per1. Notably, these molecular perturbations in Per1(-/-) -mice were accompanied by the loss of daytime-dependent differences in spatial working memory performance. Our data provide a molecular blueprint for a novel role of PER1 in temporally shaping the daytime-dependency of memory performance, likely, by gating CREB signaling, and by coupling to downstream chromatin remodeling.

Antoine, Maladies métaboliques, biliaires et fibroinflammatoire du foie, Institute of Cardiometabolism and Nutrition (ICAN).

Time of day is communicated to the body through rhythmic cues, including pineal gland melatonin synthesis, which is restricted to nighttime. Whereas in most rodents transcriptional regulation of the arylalkylamine N-acetyltransferase (Aanat) gene is essential for rhythmic melatonin synthesis, investigations into nonrodent mammalian species have shown post-transcriptional regulation to be of central importance, with molecular mechanisms still elusive. Therefore, human pineal tissues, taken from routine autopsies were allocated to four time-of-death groups (night/dawn/day/dusk) and analyzed for daytime-dependent changes in phosphorylated AANAT (p31T-AANAT) and in acetyl-serotonin-methyltransferase (ASMT) expression and activity. Protein content, intracellular localization, and colocalization of p31T-AANAT and ASMT were assessed, using immunoblotting, immunofluorescence, and immunoprecipitation techniques. Fresh sheep pineal gland preparations were used for comparative purposes. The amount of p31T-AANAT and ASMT proteins as well as their intracellular localization showed no diurnal variation in autoptic human and fresh sheep pineal glands. Moreover, in human and sheep pineal extracts, AANAT could not be dephosphorylated, which was at variance to data derived from rat pineal extracts. P31T-AANAT and ASMT were often found to colocalize in cellular rod-like structures that were also partly immunoreactive for the pinealocyte process-specific marker S-antigen (arrestin) in both, human and sheep pinealocytes. Protein-protein interaction studies with p31T-AANAT, ASMT, and S-antigen demonstrated a direct association and formation of robust complexes, involving also 14-3-3. This work provides evidence for a regulation principle for AANAT activity in the human pineal gland, which may not be based on a p31T-AANAT phosphorylation/dephosphorylation switch, as described for other mammalian species.

Background Patients with SARS-CoV-2 infection are at higher risk for ventilator-associated pneumonia (VAP). No study has evaluated the relationship between VAP and mortality in this population, or compared this relationship between SARS-CoV-2 patients and other populations. The main objective of our study was to determine the relationship between VAP and mortality in SARS-CoV-2 patients. Methods Planned ancillary analysis of a multicenter retrospective European cohort. VAP was diagnosed using clinical, radiological and quantitative microbiological criteria. Univariable and multivariable marginal Cox’s regression models, with cause-specific hazard for duration of mechanical ventilation and ICU stay, were used to compare outcomes between study groups. Extubation, and ICU discharge alive were considered as events of interest, and mortality as competing event. Findings Of 1576 included patients, 568 were SARS-CoV-2 pneumonia, 482 influenza pneumonia, and 526 no evidence of viral infection at ICU admission. VAP was associated with significantly higher risk for 28-day mortality in SARS-CoV-2 (adjusted HR 1.70 (95% CI 1.16–2.47), p = 0.006), and influenza groups (1.75 (1.03–3.02), p = 0.045), but not in the no viral infection group (1.07 (0.64–1.78), p = 0.79). VAP was associated with significantly longer duration of mechanical ventilation in the SARS-CoV-2 group, but not in the influenza or no viral infection groups. VAP was associated with significantly longer duration of ICU stay in the 3 study groups. No significant difference was found in heterogeneity of outcomes related to VAP between the 3 groups, suggesting that the impact of VAP on mortality was not different between study groups. Interpretation VAP was associated with significantly increased 28-day mortality rate in SARS-CoV-2 patients. However, SARS-CoV-2 pneumonia, as compared to influenza pneumonia or no viral infection, did not significantly modify the relationship between VAP and 28-day mortality. Clinical trial registration The study was registered at ClinicalTrials.gov, number NCT04359693.

Objective : We assessed herpesvirus reactivation in severe SARS-CoV-2 infection. Methods : Retrospective study including consecutive patients admitted to an onco-hematology intensive care unit (ICU) for severe COVID-19. Replication of EBV, CMV, and HSV was evaluated. Competing risk analyses were used to assess the cumulative risk of viral reactivation, and time-dependent Cox and Fine and Gray models to assess risk factors for viral reactivation. Results : Among 100 patients, 38 were immunocompromised. Sixty-three patients presented viral reactivation (12% for HSV, 58% EBV and 19% CMV). Symptomatic patients received treatment. Overall cumulative incidence of viral reactivation was 56.1% [55.9-56.4] at 10 days. After adjustment, a preexisting hematological malignancy (sHR [95%CI]=0.31 [0.11-0.85]) and solid organ transplantation (sHR [95% CI]=2.09 [1.13-3.87]) remained independently associated with viral reactivation. Viral reactivation ( P =0.34) was not associated with mortality. Conclusions : Incidence of herpesvirus reactivation in patients admitted to the ICU for severe COVID-19 was high, but rarely required antiviral treatment.

Background Recent multicenter studies identified COVID-19 as a risk factor for invasive pulmonary aspergillosis (IPA). However, no large multicenter study has compared the incidence of IPA between COVID-19 and influenza patients. Objectives To determine the incidence of putative IPA in critically ill SARS-CoV-2 patients, compared with influenza patients. Methods This study was a planned ancillary analysis of the coVAPid multicenter retrospective European cohort. Consecutive adult patients requiring invasive mechanical ventilation for > 48 h for SARS-CoV-2 pneumonia or influenza pneumonia were included. The 28-day cumulative incidence of putative IPA, based on Blot definition, was the primary outcome. IPA incidence was estimated using the Kalbfleisch and Prentice method, considering extubation (dead or alive) within 28 days as competing event. Results A total of 1047 patients were included (566 in the SARS-CoV-2 group and 481 in the influenza group). The incidence of putative IPA was lower in SARS-CoV-2 pneumonia group (14, 2.5%) than in influenza pneumonia group (29, 6%), adjusted cause-specific hazard ratio (cHR) 3.29 (95% CI 1.53–7.02, p = 0.0006). When putative IPA and Aspergillus respiratory tract colonization were combined, the incidence was also significantly lower in the SARS-CoV-2 group, as compared to influenza group (4.1% vs. 10.2%), adjusted cHR 3.21 (95% CI 1.88–5.46, p < 0.0001). In the whole study population, putative IPA was associated with significant increase in 28-day mortality rate, and length of ICU stay, compared with colonized patients, or those with no IPA or Aspergillus colonization. Conclusions Overall, the incidence of putative IPA was low. Its incidence was significantly lower in patients with SARS-CoV-2 pneumonia than in those with influenza pneumonia. Clinical trial registration The study was registered at ClinicalTrials.gov, number NCT04359693.