Shift work can disturb circadian homeostasis and result in fatigue, excessive sleepiness, and reduced quality of life. Light therapy has been shown to impart positive effects in night shift workers. ...We sought to determine whether or not prolonged exposure to bright light during a night shift reduces sleepiness and enhances psychomotor performance among ICU nurses.
This is a single-center randomized, crossover clinical trial at a surgical trauma ICU. ICU nurses working a night shift were exposed to a 10-h period of high illuminance (1500-2000 lx) white light compared to standard ambient fluorescent lighting of the hospital. They then completed the Stanford Sleepiness Scale and the Psychomotor Vigilance Test. The primary and secondary endpoints were analyzed using the paired t test. A p value <0.05 was considered significant.
A total of 43 matched pairs completed both lighting exposures and were analyzed. When exposed to high illuminance lighting subjects experienced reduced sleepiness scores on the Stanford Sleepiness Scale than when exposed to standard hospital lighting: mean (sem) 2.6 (0.2) vs. 3.0 (0.2), p = 0.03. However, they committed more psychomotor errors: 2.3 (0.2) vs. 1.7 (0.2), p = 0.03.
A bright lighting environment for ICU nurses working the night shift reduces sleepiness but increases the number of psychomotor errors.
ClinicalTrials.gov, NCT03331822 . Retrospectively registered on 6 November 2017.
Liver ischemia-reperfusion (I/R) injury occurs through induction of oxidative stress and release of damage-associated molecular patterns (DAMPs), including cytosolic DNA released from dysfunctional ...mitochondria or from the nucleus. Cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) synthase (cGAS) is a cytosolic DNA sensor known to trigger stimulator of interferon genes (STING) and downstream type 1 interferon (IFN-I) pathways, which are pivotal innate immune system responses to pathogen. However, little is known about the role of cGAS/STING in liver I/R injury. We subjected C57BL/6 (WT), cGAS knockout (cGAS
), and STING-deficient (STING
) mice to warm liver I/R injury and that found cGAS
mice had significantly increased liver injury compared with WT or STING
mice, suggesting a protective effect of cGAS independent of STING. Liver I/R upregulated cGAS in vivo and also in vitro in hepatocytes subjected to anoxia/reoxygenation (A/R). We confirmed a previously published finding that hepatocytes do not express STING under normoxic conditions or after A/R. Hepatocytes and liver from cGAS
mice had increased cell death and reduced induction of autophagy under hypoxic conditions as well as increased apoptosis. Protection could be restored in cGAS
hepatocytes by overexpression of cGAS or by pretreatment of mice with autophagy inducer rapamycin. Our findings indicate a novel protective role for cGAS in the regulation of autophagy during liver I/R injury that occurs independently of STING. NEW & NOTEWORTHY Our studies are the first to document the important role of cGAS in the acute setting of sterile injury induced by I/R. Specifically, we provide evidence that cGAS protects liver from I/R injury in a STING-independent manner.
Internal hernias are difficult to diagnose clinically, and normal cross-sectional imaging has been documented in many patients. Transmesenteric hernias from congenital defects or prior abdominal ...surgery are most common. A 46-year-old previously healthy female presented to the emergency department with acute onset nausea and vomiting eight years after a right ureteral transection during a laparoscopic hysterectomy, with a delayed ureterolysis and reimplantation into the bladder. Rectal contrast CT scan demonstrated a partial large bowel obstruction that was unclear if it was due to an underlying mass, stricture, or internal herniation. The patient was taken for exploratory laparotomy which demonstrated redundant transverse colon herniated under the mobile right ureter; an extended right hemicolectomy was performed. This report describes alteration of retroperitoneal anatomy creating a potential space for colonic herniation and emphasizes that clinical suspicion must remain high for patients presenting with obstructive or partially obstructive symptoms.
Clinical and biologic phenotypes of sepsis are proposed in human studies, yet it is unknown whether prognostic or drug response phenotypes are present in animal models of sepsis. Using a ...biotelemetry-enhanced, murine cecal ligation and puncture (CLP) model, we determined phenotypes of polymicrobial sepsis prior to physiologic deterioration, and the association between phenotypes and outcome in a randomized trial of prompt or delayed antibiotics and fluids.
We performed a secondary analysis of male C57BL/6J mice in two observational cohorts and two randomized, laboratory animal experimental trials. In cohort 1, mice (n = 118) underwent biotelemetry-enhanced CLP, and we applied latent class mixed models to determine optimal number of phenotypes using clinical data collected between injury and physiologic deterioration. In cohort 2 (N = 73 mice), inflammatory cytokines measured at 24 h after deterioration were explored by phenotype. In a subset of 46 mice enrolled in two trials from cohort 1, we tested the association of phenotypes with the response to immediate (0 h) vs. delayed (2 to 4 h) antibiotics or fluids initiated after physiologic deterioration.
Latent class mixture modeling derived a two-class model in cohort 1. Class 2 (N = 97) demonstrated a shorter time to deterioration (mean SD 7.3 (0.9) vs. 9.7 (3.2) h, p < 0.001) and lower heart rate at 7 h after injury (mean (SD) 564 (55) vs. 626 (35) beats per minute, p < 0.001). Overall mortality was similar between phenotypes (p = 0.75). In cohort 2 used for biomarker measurement, class 2 mice had greater plasma concentrations of IL6 and IL10 at 24 h after CLP (p = 0.05). In pilot randomized trials, the effects of sepsis treatment (immediate vs. delayed antibiotics) differed by phenotype (p = 0.03), with immediate treatment associated with greater survival in class 2 mice only. Similar differential treatment effect by class was observed in the trial of immediate vs. delayed fluids (p = 0.02).
We identified two sepsis phenotypes in a murine cecal ligation and puncture model, one of which is characterized by faster deterioration and more severe inflammation. Response to treatment in a randomized trial of immediate versus delayed antibiotics and fluids differed on the basis of phenotype.
OBJECTIVES:Sepsis, the acute organ dysfunction caused by a dysregulated host response to infection, poses a serious public health burden. Current management includes early detection, initiation of ...antibiotics and fluids, and source control as necessary. Although observational data suggest that delays of even a few hours in the initiation of antibiotics or IV fluids is associated with survival, these findings are controversial. There are no randomized data in humans, and prior animal studies studied time from experimental manipulation, not from the onset of clinical features of sepsis. Using a recently developed murine cecal ligation and puncture model that precisely monitors physiologic deterioration, we hypothesize that incremental hourly delays in the first dose of antibiotics, in the first bolus of fluid resuscitation, or a combination of the two at a clinically relevant point of physiologic deterioration during polymicrobial sepsis will shorten survival.
DESIGN:Randomized laboratory animal experimental trial.
SETTING:University basic science laboratory.
SUBJECTS:Male C57BL/6J, female C57BL/6J, aged (40–50 wk old) male C57BL/6J, and BALB/C mice.
INTERVENTIONS:Mice (n = 200) underwent biotelemetry-enhanced cecal ligation and puncture and were randomized after meeting validated criteria for acute physiologic deterioration. Treatment groups consisted of a single dose of imipenem/cilastatin, a single bolus of 30 mL/kg fluid resuscitation, or a combination of the two. Mice were allocated to receive treatment at the time of meeting deterioration criteria, after a 2-hour delay or after a 4-hour delay.
MEASUREMENTS AND MAIN RESULTS:Hourly delays in the initiation of antibiotic therapy led to progressively shortened survival in our model (p < 0.001). The addition of fluid resuscitation was unable to rescue animals, which received treatment 4 hours after meeting enrollment criteria. Systemic inflammation was increased, and host physiology was increasingly deranged with hourly delays to antibiotics.
CONCLUSIONS:We conclude that antibiotic therapy is highly time sensitive, and efforts should be made to deliver this critical therapy as early as possible in sepsis, perhaps extending into the first point of medical contact outside the hospital.
The wavelength of light is a critical determinant of light's capacity to entrain adaptive biological mechanisms, such as enhanced immune surveillance, that precede and prepare us for the active ...circadian day, a time when the risk of encountering pathogen is highest. Light rich in the shorter wavelength visible blue spectrum maximally entrains these circadian rhythms. We hypothesized that exposure to blue light during sepsis will augment immunity and improve outcome. Using a clinically relevant Klebsiella pneumoniae acute lower respiratory tract infection model, we show that blue spectrum light shifts autonomic tone toward parasympathetic predominance and enhances immune competence, as characterized by accelerated pathogen clearance that is accompanied by reduced alveolar neutrophil influx, inflammation, and improved survival. Blue light functioned through an optic‐cholinergic pathway and expansion of splenic Ccr2+ monocytes to increase control of the infection and improve survival. The “keystone” mediating these effects is the circadian clock protein Rev‐Erbα, and biochemical activation with Rev‐Erbα agonist SR9009 enhanced mononuclear cell phagocytosis in vitro and recapitulated the enhanced pathogen elimination in vivo observed with blue light. These findings underscore the potential therapeutic value of blue light and modulating Rev‐Erbα to enhance host immunity against infection.
Blue light enhances immune competence during pneumonia, facilitating elimination of the offending pathogen and improving survival, while reducing neutrophil influx, regional cytokine production and inflammation.
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•An important role for bioenergetic dysfunction in the development of multiple organ dysfunction has been identified.•During sepsis, CaMKIV links mitochondrial stress with adaptive ...mechanisms of mitochondrial fission, fusion and mitophagy.•CaMKIV funtions as a direct PINK1-kinase to induce Parkin-dependent mitophagy and slow oxidative metabolism.•CaMKIV shifts the balance away from fusion and towards fission, which correlates with reduced toxic protein oxidation.
Sepsis and shock states impose mitochondrial stress, and in response, adaptive mechanisms such as fission, fusion and mitophagy are induced to eliminate damaged portions of or entire dysfunctional mitochondria. The mechanisms underlying these events are being elucidated; yet a direct link between loss of mitochondrial membrane potential ΔΨm and the initiation of fission, fusion and mitophagy remains to be well characterized. The direct association between the magnitude of the ΔΨm and the capacity for mitochondria to buffer Ca2+ renders Ca2+ uniquely suited as the signal engaging these mechanisms in circumstances of mitochondrial stress that lower the ΔΨm. Herein, we show that the calcium/calmodulin-dependent protein kinase (CaMK) IV mediates an adaptive slowing in oxidative respiration that minimizes oxidative stress in the kidneys of mice subjected to either cecal ligation and puncture (CLP) sepsis or endotoxemia. CaMKIV shifts the balance towards mitochondrial fission and away from fusion by 1) directly phosphorylating an activating Serine616 on the fission protein DRP1 and 2) reducing the expression of the fusion proteins Mfn1/2 and OPA-1. CaMKIV, through its function as a direct PINK1 kinase and regulator of Parkin expression, also enables mitophagy. These data support that CaMKIV serves as a keystone linking mitochondrial stress with the adaptive mechanisms of mitochondrial fission, fusion and mitophagy that mitigate oxidative stress in the kidneys of mice responding to sepsis.
OBJECTIVES:The physiology of nearly all mammalian organisms are entrained by light and exhibit circadian rhythm. The data derived from animal studies show that light influences immunity, and these ...neurophysiologic pathways are maximally entrained by the blue spectrum. Here, we hypothesize that bright blue light reduces acute kidney injury by comparison with either bright red or standard, white fluorescent light in mice subjected to sepsis. To further translational relevance, we performed a pilot clinical trial of blue light therapy in human subjects with appendicitis.
DESIGN:Laboratory animal research, pilot human feasibility trial.
SETTING:University basic science laboratory and tertiary care hospital.
SUBJECTS:Male C57BL/6J mice, adult (> 17 yr) patients with acute appendicitis.
INTERVENTIONS:Mice underwent cecal ligation and puncture and were randomly assigned to a 24-hour photoperiod of bright blue, bright red, or ambient white fluorescent light. Subjects with appendicitis were randomized to receive postoperatively standard care or standard care plus high-illuminance blue light.
MEASUREMENTS AND MAIN RESULTS:Exposure to bright blue light enhanced bacterial clearance from the peritoneum, reduced bacteremia and systemic inflammation, and attenuated the degree of acute kidney injury. The mechanism involved an elevation in cholinergic tone that augmented tissue expression of the nuclear orphan receptor REV-ERBα and occurred independent of alterations in melatonin or corticosterone concentrations. Clinically, exposure to blue light after appendectomy was feasible and reduced serum interleukin-6 and interleukin-10 concentrations.
CONCLUSIONS:Modifying the spectrum of light may offer therapeutic utility in sepsis.
Circadian rhythms regulate adaptive alterations in mammalian physiology and are maximally entrained by the short wavelength blue spectrum; cataracts block the transmission of light, particularly blue ...light. Cataract surgery is performed with two types of intraocular lenses (IOL): (1) conventional IOL that transmit the entire visible spectrum and (2) blue-light-filtering (BF) IOL that block the short wavelength blue spectrum. We hypothesized that the transmission properties of IOL are associated with long-term survival. This retrospective cohort study of a 15-hospital healthcare system identified 9,108 participants who underwent bilateral cataract surgery; 3,087 were implanted with conventional IOL and 6,021 received BF-IOL. Multivariable Cox proportional hazards models that included several a priori determined subgroup and sensitivity analyses yielded estimates supporting that conventional IOL compared with BF-IOL may be associated with significantly reduced risk of long-term death. Confirming these differences and identifying any potential causal mechanisms await the conduct of appropriately controlled prospective translational trials.
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•Risk of all-cause mortality in 9,108 patients after bilateral cataract surgery•Comparison of conventional intraocular lenses to blue-light-filtering intraocular lenses•Conventional lenses that transmit the entire visible spectrum may improve survival•Glaucoma patients particularly may benefit from conventional intraocular lenses
Medicine; Ophthalmology; Biological Sciences; Neuroscience
Sepsis and shock states impose mitochondrial stress, and in response, adaptive mechanisms such as fission, fusion and mitophagy are induced to eliminate damaged portions of or entire dysfunctional ...mitochondria. The mechanisms underlying these events are being elucidated; yet a direct link between loss of mitochondrial membrane potential ΔΨm and the initiation of fission, fusion and mitophagy remains to be well characterized. The direct association between the magnitude of the ΔΨm and the capacity for mitochondria to buffer Ca
2+
renders Ca
2+
uniquely suited as the signal engaging these mechanisms in circumstances of mitochondrial stress that lower the ΔΨm. Herein, we show that the calcium/calmodulin-dependent protein kinase (CaMK) IV mediates an adaptive slowing in oxidative respiration that minimizes oxidative stress in the kidneys of mice subjected to either cecal ligation and puncture (CLP) sepsis or endotoxemia. CaMKIV shifts the balance towards mitochondrial fission and away from fusion by 1) directly phosphorylating an activating Serine616 on the fission protein DRP1 and 2) reducing the expression of the fusion proteins Mfn1/2 and OPA-1. CaMKIV, through its function as a direct PINK1 kinase and regulator of Parkin expression, also enables mitophagy. These data support that CaMKIV serves as a keystone linking mitochondrial stress with the adaptive mechanisms of mitochondrial fission, fusion and mitophagy that mitigate oxidative stress in the kidneys of mice responding to sepsis.
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