The complement cascade not only provides protection from infection but can also mediate destructive inflammation. Complement is also involved in elimination of neuronal synapses which is essential ...for proper development, but can be detrimental during aging and disease. C1q, required for several of these complement-mediated activities, is present in the neuropil, microglia, and a subset of interneurons in the brain.
To identify the source(s) of C1q in the brain, the C1qa gene was selectively inactivated in the microglia or Thy-1
neurons in both wild type mice and a mouse model of Alzheimer's disease (AD), and C1q synthesis assessed by immunohistochemistry, QPCR, and western blot analysis.
While C1q expression in the brain was unaffected after inactivation of C1qa in Thy-1
neurons, the brains of C1qa
:Cx3cr1
mice in which C1qa was ablated in microglia were devoid of C1q with the exception of limited C1q in subsets of interneurons. Surprisingly, this loss of C1q occurred even in the absence of tamoxifen by 1 month of age, demonstrating that Cre activity is tamoxifen-independent in microglia in Cx3cr1
mice. C1q expression in C1qa
: Cx3cr1
mice continued to decline and remained almost completely absent through aging and in AD model mice. No difference in C1q was detected in the liver or kidney from C1qa
: Cx3cr1
mice relative to controls, and C1qa
: Cx3cr1
mice had minimal, if any, reduction in plasma C1q.
Thus, microglia, but not neurons or peripheral sources, are the dominant source of C1q in the brain. While demonstrating that the Cx3cr1
deleter cannot be used for adult-induced deletion of genes in microglia, the model described here enables further investigation of physiological roles of C1q in the brain and identification of therapeutic targets for the selective control of complement-mediated activities contributing to neurodegenerative disorders.
Pharmacologic inhibition of C5aR1, a receptor for the complement activation proinflammatory fragment, C5a, suppressed pathology and cognitive deficits in Alzheimer's disease (AD) mouse models. To ...validate that the effect of the antagonist was specifically via C5aR1 inhibition, mice lacking C5aR1 were generated and compared in behavior and pathology. In addition, since C5aR1 is primarily expressed on cells of the myeloid lineage, and only to a lesser extent on endothelial cells and neurons in brain, gene expression in microglia isolated from adult brain at multiple ages was compared across all genotypes.
C5aR1 knock out mice were crossed to the Arctic AD mouse model, and characterized for pathology and for behavior performance in a hippocampal dependent memory task. CX3CR1
and CCR2
reporter mice were bred to C5aR1 sufficient and knockout wild type and Arctic mice to enable sorting of microglia (GFP-positive, RFP-negative) isolated from adult brain at 2, 5, 7 and 10 months of age followed by RNA-seq analysis.
A lack of C5aR1 prevented behavior deficits at 10 months, although amyloid plaque load was not altered. Immunohistochemical analysis showed no CCR2
monocytes/macrophages near the plaques in the Arctic brain with or without C5aR1. Microglia were sorted from infiltrating monocytes (GFP and RFP-positive) for transcriptome analysis. RNA-seq analysis identified inflammation related genes as differentially expressed, with increased expression in the Arctic mice relative to wild type and decreased expression in the Arctic/C5aR1KO relative to Arctic. In addition, phagosomal-lysosomal gene expression was increased in the Arctic mice relative to wild type but further increased in the Arctic/C5aR1KO mice. A decrease in neuronal complexity was seen in hippocampus of 10 month old Arctic mice at the time that correlates with the behavior deficit, both of which were rescued in the Arctic/C5aR1KO.
These data are consistent with microglial polarization in the absence of C5aR1 signaling reflecting decreased induction of inflammatory genes and enhancement of degradation/clearance pathways, which is accompanied by preservation of CA1 neuronal complexity and hippocampal dependent cognitive function. These results provide links between microglial responses and loss of cognitive performance and, combined with the previous pharmacological approach to inhibit C5aR1 signaling, support the potential of this receptor as a novel therapeutic target for AD in humans.
MEK inhibitors (MEKi) have shown efficacy in pediatric low-grade glioma as well as plexiform neurofibroma. MEKi have been associated with acute cardiac dysfunction in adults. Cardiac consequences in ...children are unknown. We performed a single center retrospective cohort study evaluating cardiac function by echocardiography (echo) in children and young adults < 21 years receiving MEKi between October 2013 and May 2018. Blinded assessment of left ventricular function by fractional shortening (FS) and ejection fraction (EF) was performed on all available echocardiograms performed before, during, and following therapy, as well as after re-initiation of therapy. Twenty-six patients underwent MEKi therapy with echo follow-up during the study period. Twenty-four of these had complete echo data. Median follow-up was 12 months. Borderline EF (EF 53–57.9%) occurred in 12 (50%) patients; and 3 (12.5%) progressed to abnormal EF (EF < 53%). Cardiac dysfunction, when it occurred, was mild (lowest documented EF was 45%, and lowest FS was 24.4%). EF abnormalities typically fluctuated during therapy, resolved off therapy, and recurred with MEKi re-initiation. No clinical or demographic differences were detected between those who maintained normal cardiac function and those who developed borderline or overt cardiac dysfunction. Symptomatic heart failure did not occur. In this cohort of children and young adults, MEKi use was associated with a high (50%) incidence of borderline or mildly decreased left ventricular function. There was no evidence of permanent cardiac dysfunction. Further evaluation in larger prospective trials is needed.
To understand the changes in gene expression that occur as a result of age, which might create a permissive or causal environment for age-related diseases, we produce a multi-time point age-related ...gene expression signature (AGES) from liver, kidney, skeletal muscle, and hippocampus of rats, comparing 6-, 9-, 12-, 18-, 21-, 24-, and 27-month-old animals. We focus on genes that changed in one direction throughout the lifespan of the animal, either early in life (early logistic changes), at mid-age (mid-logistic), late in life (late-logistic), or linearly, throughout the lifespan of the animal. The pathways perturbed because of chronological age demonstrate organ-specific and more-global effects of aging and point to mechanisms that could potentially be counter-regulated pharmacologically to treat age-associated diseases. A small number of genes are regulated by aging in the same manner in every tissue, suggesting they may be more-universal markers of aging.
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•A multi-tissue age-related gene expression signature (AGES) is constructed•Linear, early, middle-, and late-life expression changes are discovered•AGES points to potential mechanisms inducing age-related disorders•Gene changes in multiple tissues include upregulation of interferon signaling
Shavlakadze et al. studied gene expression changes occurring because of aging throughout the lifespan of rats, examining liver, skeletal muscle, kidney, and the hippocampus. The study should serve as a valuable resource for the discovery of biomarkers and mediators of age-related disorders.
High concentrations of adrenocorticotropic hormone (ACTH) are used as an indicator of pituitary pars intermedia dysfunction (PPID), but other factors that may influence ACTH need to be understood, if ...diagnostic reference ranges for ACTH are to be used with confidence. Insulin dysregulation (ID) could be one such factor, as insulin affects pituitary hormones in other species.
To test the hypothesis that a relationship exists between high insulin and high ACTH in aged (>15-year-old) animals with no clinical signs of PPID.
A cohort study.
Thirteen horses and eleven ponies (17-25 years-old; mares and geldings) were clinically examined for signs of PPID in the spring (November 2020) and autumn (April 2021). On the same day, blood samples were taken before and 2 h after an oral glucose test (OGT). Concentrations of insulin, glucose, ACTH and cortisol were measured.
There was no association between ACTH and cortisol. However, there was a positive linear correlation between ACTH and post-OGT (insulin in the autumn (r = 0.427, p = 0.04). Two horses and six ponies had ACTH above the cut-off value for PPID diagnosis, and of these eight animals, six also had insulin concentrations above the cut-off value for ID.
The cohort was small and thyrotropin-releasing hormone (TRH) stimulation tests were not performed.
In autumn, high ACTH was associated with ID, when no clinical signs of PPID were present. Because ACTH is used in PPID diagnosis, further work is required to understand this interaction.
Patterns of genetic and genomic variance are informative in inferring population history for human, model species and endangered populations.
Here the genome sequence of wild-born African cheetahs ...reveals extreme genomic depletion in SNV incidence, SNV density, SNVs of coding genes, MHC class I and II genes, and mitochondrial DNA SNVs. Cheetah genomes are on average 95 % homozygous compared to the genomes of the outbred domestic cat (24.08 % homozygous), Virunga Mountain Gorilla (78.12 %), inbred Abyssinian cat (62.63 %), Tasmanian devil, domestic dog and other mammalian species. Demographic estimators impute two ancestral population bottlenecks: one >100,000 years ago coincident with cheetah migrations out of the Americas and into Eurasia and Africa, and a second 11,084-12,589 years ago in Africa coincident with late Pleistocene large mammal extinctions. MHC class I gene loss and dramatic reduction in functional diversity of MHC genes would explain why cheetahs ablate skin graft rejection among unrelated individuals. Significant excess of non-synonymous mutations in AKAP4 (p<0.02), a gene mediating spermatozoon development, indicates cheetah fixation of five function-damaging amino acid variants distinct from AKAP4 homologues of other Felidae or mammals; AKAP4 dysfunction may cause the cheetah's extremely high (>80 %) pleiomorphic sperm.
The study provides an unprecedented genomic perspective for the rare cheetah, with potential relevance to the species' natural history, physiological adaptations and unique reproductive disposition.
Background Despite the benefits of targeted temperature management (TTM) for out-of-hospital cardiac arrest), implementation within the United States remains low. The objective of this study was to ...evaluate the prevalence and factors associated with TTM use in a large, urban-suburban regional system of care. Methods and Results This was a retrospective analysis from the Los Angeles County regional cardiac system of care serving a population of >10 million residents. All adult patients aged ≥18 years with non-traumatic out-of-hospital cardiac arrest transported to a cardiac arrest center from April 2011 to August 2017 were included. Patients awake and alert in the emergency department and patients who died in the emergency department before consideration for TTM were excluded. The primary outcome measure was prevalence of TTM use. The secondary analysis were annual trends in TTM use over the study period and factors associated with TTM use. The study population included 8072 patients; 4154 patients (51.5%) received TTM and 3767 patients (46.7%) did not receive TTM. Median age was 67 years, 4780 patients (59.2%) were men, 4645 patients (57.5%) were non-White, and the most common arrest location was personal residence in 4841 patients (60.0%). In the adjusted analysis, younger age, male sex, an initial shockable rhythm, witnessed arrest, and receiving coronary angiography were associated with receiving TTM. Conclusions Within this regional system of care, use of TTM was higher than previously reported in the literature at just over 50%. Use of integrated systems of care may be a novel method to increase TTM use within the United States.
IntroductionPostoperative delirium (POD) is a common serious postoperative complication especially in older people and is associated with increased mortality, morbidity and healthcare costs. There is ...no clear consensus which anaesthesia is associated with less incidence of POD for older patients. We aim to assess whether regional anaesthesia results in lower incidence of POD comparing with general anaesthesia (GA) among older patients undergoing hip fracture surgery.Methods and analysisRAGA-delirium is a pragmatic, multicentre, prospective, parallel grouped, randomised controlled clinical trial comparing RA or GA for hip fracture surgery. A total of 1000 patients who are 65 years or over and who are having planned hip fracture surgery in nine clinical trial centres of China will be randomised in a 1:1 ratio to receive either anaesthesia for the surgery. The primary endpoint will be the incidence of POD at day 7. The secondary endpoints will be the subtype, severity and duration of delirium, postoperative acute pain score, incidence of other postoperative non-delirium complications, quality of life and cost-effective outcomes. Randomisation will be performed at the patient level using computer-generated assignment. Outcome assessors will be blinded from intervention assignment. Assessments will be conducted before surgery, intraoperatively, postoperatively, during the hospital stay, at 30-day, 6-month and 1-year postoperative intervals.Potential impact of studyThis study will provide clinical evidence with a more robust methodology to help anaesthetists in selecting appropriate anaesthesia for older patients with high risk for POD. At the era of increasing emphasis on delirium prevention, this trial has the potential to inform the future national guideline to reduce POD.Ethics and disseminationEthical approved by the local institutional review board. Trial results will be presented at national and international academic conferences, and published in peer-reviewed journals.Trial registration numberClinicalTrials.gov (NCT02213380); pre-results.
Malassezia globosa is abundant and prevalent on sebaceous areas of the human skin. Genome annotation reveals that M. globosa possesses a repertoire of secreted hydrolytic enzymes relevant for lipid ...and protein metabolism. However, the functional significance of these enzymes is uncertain and presence of these genes in the genome does not always translate to expression at the cutaneous surface. In this study we utilized targeted RNA sequencing from samples isolated directly from the skin to quantify gene expression of M. globosa secreted proteases, lipases, phospholipases and sphingomyelinases. Our findings indicate that the expression of these enzymes is dynamically regulated by the environment in which the fungus resides, as different growth phases of the planktonic culture of M. globosa show distinct expression levels. Furthermore, we observed significant differences in the expression of these enzymes in culture compared to healthy sebaceous skin sites. By examining the in situ gene expression of M. globosa's secreted hydrolases, we identified a predicted aspartyl protease, MGL_3331, which is highly expressed on both healthy and disease-affected dermatological sites. However, molecular modeling and biochemical studies revealed that this protein has a non-canonical active site motif and lacks measurable proteolytic activity. This pseudoprotease MGL_3331 elicits a heightened IgE-reactivity in blood plasma isolated from patients with atopic dermatitis compared to healthy individuals and invokes a pro-inflammatory response in peripheral blood mononuclear cells. Overall, our study highlights the importance of studying fungal proteins expressed in physiologically relevant environments and underscores the notion that secreted inactive enzymes may have important functions in influencing host immunity.
Patient and staff experiences are strongly influenced by attitudes and behaviours, and provide important insights into care quality. Patient and staff feedback could be used more effectively to ...enhance behaviours and improve care through systematic integration with techniques for reflective learning. We aim to develop a reflective learning framework and toolkit for healthcare staff to improve patient, family and staff experience.
Local project teams including staff and patients from the acute medical units (AMUs) and intensive care units (ICUs) of three National Health Service trusts will implement two experience surveys derived from existing instruments: a continuous patient and relative survey and an annual staff survey. Survey data will be supplemented by ethnographic interviews and observations in the workplace to evaluate barriers to and facilitators of reflective learning. Using facilitated iterative co-design, local project teams will supplement survey data with their experiences of healthcare to identify events, actions, activities and interventions which promote personal insight and empathy through reflective learning. Outputs will be collated by the central project team to develop a reflective learning framework and toolkit which will be fed back to the local groups for review, refinement and piloting. The development process will be mapped to a conceptual theory of reflective learning which combines psychological and pedagogical theories of learning, alongside theories of behaviour change based on capability, opportunity and motivation influencing behaviour. The output will be a locally-adaptable workplace-based toolkit providing guidance on using reflective learning to incorporate patient and staff experience in routine clinical activities.
The PEARL project has received ethics approval from the London Brent Research Ethics Committee (REC Ref 16/LO/224). We propose a national cluster randomised step-wedge trial of the toolkit developed for large-scale evaluation of impact on patient outcomes.
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