bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative genome analyses suggest a hemibiotrophic lifestyle and virulence differences for the beech bark disease fungal pathogens Neonectria faginata and Neonectria coccinea
Authors: Salgado-Salazar Catalina , Skaltsas Demetra N , Phipps Tunesha , Castlebury Lisa A
Published: March 2021

Neonectria faginata and Neonectria coccinea are the causal agents of the insect-fungus disease complex known as beech bark disease (BBD), known to cause mortality in beech forest stands in North America and Europe. These fungal species have been the focus of extensive ecological and disease management studies, yet less progress has been made toward generating genomic resources for both micro- and macro-evolutionary studies. Here, we report a 42.1 and 42.7 mb highly contiguous genome assemblies of N. faginata and N. coccinea, respectively, obtained using Illumina technology. These species share similar gene number counts (12,941 and 12,991) and percentages of predicted genes with assigned functional categories (64 and 65%). Approximately 32% of the predicted proteomes of both species are homologous to proteins involved in pathogenicity, yet N. coccinea shows a higher number of predicted mitogen-activated protein kinase genes, virulence determinants possibly contributing to differences in disease severity between N. faginata and N. coccinea. A wide range of genes encoding for carbohydrate-active enzymes capable of degradation of complex plant polysaccharides and a small number of predicted secretory effector proteins, secondary metabolite biosynthesis clusters and cytochrome oxidase P450 genes were also found. This arsenal of enzymes and effectors correlates with, and reflects, the hemibiotrophic lifestyle of these two fungal pathogens. Phylogenomic analysis and timetree estimations indicated that the N. faginata and N. coccinea species divergence may have occurred at ∼4.1 million years ago. Differences were also observed in the annotated mitochondrial genomes as they were found to be 81.7 kb (N. faginata) and 43.2 kb (N. coccinea) in size. The mitochondrial DNA expansion observed in N. faginata is attributed to the invasion of introns into diverse intra- and intergenic locations. These first draft genomes of N. faginata and N. coccinea serve as valuable tools to increase our understanding of basic genetics, evolutionary mechanisms and molecular physiology of these two nectriaceous plant pathogenic species.
Transcriptome Expression of Biomineralization Genes inLittoraria flavaGastropod in Brazilian Rocky Shore Reveals Evidence of Local Adaptation
Authors: Santos Camilla A , Sonoda Gabriel G , Cortez Thainá , Coutinho Luiz L , Andrade Sónia C S
Published: March 2021

Understanding how selection shapes population differentiation and local adaptation in marine species remains one of the greatest challenges in the field of evolutionary biology. The selection of genes in response to environment-specific factors and microenvironmental variation often results in chaotic genetic patchiness, which is commonly observed in rocky shore organisms. To identify these genes, the expression profile of the marine gastropod Littoraria flava collected from four Southeast Brazilian locations in ten rocky shore sites was analyzed. In this first L. flava transcriptome, 250,641 unigenes were generated, and 24% returned hits after functional annotation. Independent paired comparisons between 1) transects, 2) sites within transects, and 3) sites from different transects were performed for differential expression, detecting 8,622 unique differentially expressed genes. Araçá (AR) and São João (SJ) transect comparisons showed the most divergent gene products. For local adaptation, fitness-related differentially expressed genes were chosen for selection tests. Nine and 24 genes under adaptative and purifying selection, respectively, were most related to biomineralization in AR and chaperones in SJ. The biomineralization-genes perlucin and gigasin-6 were positively selected exclusively in the site toward the open ocean in AR, with sequence variants leading to pronounced protein structure changes. Despite an intense gene flow among L. flava populations due to its planktonic larva, gene expression patterns within transects may be the result of selective pressures. Our findings represent the first step in understanding how microenvironmental genetic variation is maintained in rocky shore populations and the mechanisms underlying local adaptation in marine species.
Transcriptional Control of the Production of Aspergillus fumigatus Conidia-Borne Secondary Metabolite Fumiquinazoline C Important for Phagocytosis Protection
Authors: Rocha Marina Campos , Fabri João Henrique Tadini Marilhano , Silva Lilian Pereira , Angolini Célio Fernando Figueiredo , Bertolini Maria Célia , da Cunha Anderson Ferreira , Valiante Vito , Goldman Gustavo Henrique , Fill Taicia Pacheco , Malavazi Iran
Published: March 2021

Aspergillus fumigatus produces diverse secondary metabolites whose biological functions and regulation remain to be understood. Despite the importance of the conidia for this fungus, the role of the conidia-born metabolite fumiquinazoline C (FqC) is unclear. Here, we describe a dual function of the cell-wall integrity pathway in regulating FqC biosynthesis dictated by the MAPK kinase MpkA, which phosphorylates one of the nonribosomal peptide synthetases enzymes of the cluster (FmqC), and the transcription factor RlmA, which directly regulates the expression of fmq genes. Another level of crosstalk between the FqC regulation and the cell physiology is described since the deletion of the stress-responsive transcription factor sebA provokes derepression of the fmq cluster and overproduction of FqC. Thus, we describe a mechanism by which A. fumigatus controls FqC biosynthesis orchestrated by MpkA-RlmA and SebA and hence enabling survival and adaptation to the environmental niche, given that FqC is a deterrent of ameba predation.
Detecting de novo mitochondrial mutations in angiosperms with highly divergent evolutionary rates
Authors: Broz Amanda K , Waneka Gus , Wu Zhiqiang , Fernandes Gyorfy Matheus , Sloan Daniel B
Published: March 2021

Although plant mitochondrial genomes typically show low rates of sequence evolution, levels of divergence in certain angiosperm lineages suggest anomalously high mitochondrial mutation rates. However, de novo mutations have never been directly analyzed in such lineages. Recent advances in high-fidelity DNA sequencing technologies have enabled detection of mitochondrial mutations when still present at low heteroplasmic frequencies. To date, these approaches have only been performed on a single plant species (Arabidopsis thaliana). Here, we apply a high-fidelity technique (Duplex Sequencing) to multiple angiosperms from the genus Silene, which exhibits extreme heterogeneity in rates of mitochondrial sequence evolution among close relatives. Consistent with phylogenetic evidence, we found that Silene latifolia maintains low mitochondrial variant frequencies that are comparable with previous measurements in Arabidopsis. Silene noctiflora also exhibited low variant frequencies despite high levels of historical sequence divergence, which supports other lines of evidence that this species has reverted to lower mitochondrial mutation rates after a past episode of acceleration. In contrast, S. conica showed much higher variant frequencies in mitochondrial (but not in plastid) DNA, consistent with an ongoing bout of elevated mitochondrial mutation rates. Moreover, we found an altered mutational spectrum in S. conica heavily biased towards AT→GC transitions. We also observed an unusually low number of mitochondrial genome copies per cell in S. conica, potentially pointing to reduced opportunities for homologous recombination to accurately repair mismatches in this species. Overall, these results suggest that historical fluctuations in mutation rates are driving extreme variation in rates of plant mitochondrial sequence evolution.
Aging Changes in Bladder Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels Are Associated With Increasing Heterogeneity of Adrenergic/Mucosal Influence on Detrusor Control in the Mouse
Authors: Hardy Cara C , Al-Naggar Iman M , Kuo Chia-Ling , Kuchel George A , Smith Phillip P
Published: March 2021

A geroscience-informed approach to the increasing prevalence of bladder control problems in older adults requires understanding the impact of aging on dynamic mechanisms that ensure resilience in response to stressors challenging asymptomatic voluntary control over urine storage and voiding. Bladder control is predicated on sensory neural information about bladder volume. Modulation of volume-induced bladder wall tensions by autonomic and mucosal factors controls neural sensitivity to bladder volume. We hypothesized that hyperpolarization-activated cyclic nucleotide-gated (HCN) channels integrate these factors and thereby mediate adrenergic detrusor tension control. Furthermore, loss of HCN expression compromises that integration and could result in loss of precision of detrusor control. Using a life-span mouse model, reverse transcription quantitative real-time PCR and pharmacologic studies in pretensioned intact and mucosa-denuded bladder strips were made. The dominant hcn1 expression declines with maturation and aging; however, aging is also associated with increased variance around mean values. In strips from Mature animals, isoproterenol had less effect in denuded muscle strips than in intact strips, and HCN blockade diminished isoproterenol responsiveness. With aging, variances about mean response values significantly increased, paralleling hcn1 expression. Our findings support a role for HCN in providing neuroendocrine/paracrine integration and suggest an association of increased heterogeneity of HCN expression in aging with reductions in response precision to neuroendocrine control. The functional implication is an increased risk of dysfunction of brainstem/bladder regulation of neuronal sensitivity to bladder volume. This supports the clinical model of the aging bladder phenotype as an expression of loss of resilience, and not as emerging bladder pathology with aging.
Constructing time in foreign policy-making: Brexit's timing entrepreneurs, malcontemps and apparatchiks
Authors: Hom Andrew , Beasley Ryan
Published: March 2021

Temporal considerations play a role in many models of foreign policy analysis, particularly those focused on decision-making processes. While time features prominently as a background feature against which sequence, cadence and psychological consequence are measured, little attention has been given to how foreign policy agents actively construct their temporal environments. We propose that different foreign policy-making actors develop distinct relationships with time, and that variations in these relationships can help account for the ways in which ‘events’ are transformed into routine practices, change opportunities or full-blown foreign policy crises. We advance a novel conception of time in foreign policy-making through our development of timing theory and the linguistic constructions of ‘time’ by foreign policy actors. We propose a typology of timing agency, which highlights the impact of these orientations on decision-making processes as well as the characteristics of foreign policy behaviours. Using the case of Brexit, we elaborate differences in actors' temporal orientations and show how such differences impact the making of foreign policy.
Far-right populism and foreign policy identity: Jair Bolsonaro's ultra-conservatism and the new politics of alignment
Authors: De Sá Guimarães Feliciano , De Oliveira E Silva Irma Dutra
Published: March 2021

In the last two decades, far-right populists have formed governments all over the world. However, systematic analyses on how far-right leaders recreate their countries' foreign policy identity are still underdeveloped. In this article, we analyse how far-right populist leaders use their conservative identity-set to align with other right-wing governments and how they use the same conservative repertoire to deal with ideological rivals. More precisely, we argue that these leaders tend to overemphasize a deep conservative identity-set towards other far-right populist governments, something we call ‘thick conservative identity’. This profoundly conservative identity-set is composed of three national role conceptions: anti-globalism, nationalism and anti-foe. However, they do not repeat this identity-set towards ideological rivals, preferring to use a more nuanced and contradictory one, something we call ‘thin conservative identity’. The trigger of such difference is the anticipated mutual expectation of conservatism between Ego and Alter, in which Ego mimics Alter's deep conservatism. We use Jair Bolsonaro's alignment with Donald Trump and Bolsonaro's relationship with China as illustrative cases. We use the main concepts of role theory to understand both how conservative alignments are created and how far-right governments deal with ideological rivals.
A Single Educational Intervention Improves Pregnancy-Related Knowledge and Emotional Health Among Women With IBD Who Are Pregnant or Wish to Conceive
Authors: Flanagan Emma , Wright Emily K , Sparrow Miles P , Moore Gregory T , Connell William R , De Cruz Peter , Christensen Britt , Shelton Edward , Kamm Michael A , Ward Mark G , Dowling Damian , Brown Steven , Kashkooli Soleiman , Thompson Alexander J , Ross Alyson L , Kiburg Katerina V , Bell Sally J
Published: March 2021

Background

There is considerable interest in improving the education and care of women with inflammatory bowel disease (IBD) to improve pregnancy outcomes. Despite increased awareness, not all women with IBD have access to pregnancy-related education and the quality of counseling is variable. We aimed to assess the effectiveness of a simple educational intervention for improving pregnancy-related knowledge and to evaluate the effect of education on patient outcomes including anxiety, depression, and quality of life in women with IBD.

Methods

This prospective study of women with IBD who were pregnant or planning a pregnancy evaluated the effectiveness of a single gastroenterologist-led educational intervention in improving pregnancy-related knowledge, measured using the Crohn’s and Colitis Pregnancy Knowledge score 1 month postintervention. Secondary outcomes included the effect on anxiety and depression, quality of life, medication adherence, and patient satisfaction.

Results

One hundred women with IBD were recruited. Fifty percent were pregnant at the time of the intervention. Baseline knowledge scores were similar independent of the patients’ pregnancy status or whether they had previously received counseling from their gastroenterologist. Median Crohn’s and Colitis Pregnancy Knowledge scores postintervention (n = 82) were higher than preintervention scores (14/17 vs 10/17; P < 0.001). In addition, 32% of patients had poor knowledge at baseline (score ≤7/17), compared to only 5% after the intervention (P < 0.001). There was a significant improvement in total anxiety and depression and quality of life scores postintervention. Medication adherence and patient satisfaction were excellent.

Conclusions

Uptake of this gastroenterologist-led educational intervention has the potential to improve pregnancy knowledge, promote medication adherence, and enhance quality of life for women with IBD globally.
The association between perceived electronic health record usability and professional burnout among US nurses
Authors: Melnick Edward R , West Colin P , Nath Bidisha , Cipriano Pamela F , Peterson Cheryl , Satele Daniel V , Shanafelt Tait , Dyrbye Liselotte N
Published: March 2021

Objectives

To measure nurse-perceived electronic health records (EHR) usability with a standardized metric of technology usability and evaluate its association with professional burnout.

Methods

A cross-sectional survey of a random sample of US nurses was conducted in November 2017. EHR usability was measured with the System Usability Scale (SUS; range 0–100) and burnout with the Maslach Burnout Inventory.

Results

Among the 86 858 nurses who were invited, 8638 (9.9%) completed the survey. The mean nurse-rated EHR SUS score was 57.6 (SD 16.3). A score of 57.6 is in the bottom 24% of scores across previous studies and categorized with a grade of “F.” On multivariable analysis adjusting for age, gender, race, ethnicity, relationship status, children, highest nursing-related degree, mean hours worked per week, years of nursing experience, advanced certification, and practice setting, nurse-rated EHR usability was associated with burnout with each 1 point more favorable SUS score and associated with a 2% lower odds of burnout (OR 0.98; 95% CI, 0.97–0.99; P < .001).

Conclusions

Nurses rated the usability of their current EHR in the low marginal range of acceptability using a standardized metric of technology usability. EHR usability and the odds of burnout were strongly associated with a dose-response relationship.
Bacterial community analysis of purulent material from liver abscesses of crossbred cattle and Holstein steers fed finishing diets with or without tylosin
Authors: Amachawadi Raghavendra G , Tom Wesley A , Hays Michael P , Fernando Samodha C , Hardwidge Philip R , Nagaraja T G
Published: March 2021

Liver abscesses in feedlot cattle are polymicrobial infections. Culture-based studies have identified Fusobacterium necrophorum as the primary causative agent, but a number of other bacterial species are frequently isolated. The incidence of liver abscesses is highly variable and is affected by a number of factors, including cattle type. Holstein steers raised for beef production have a higher incidence than crossbred feedlot cattle. Tylosin is the commonly used antimicrobial feed additive to reduce the incidence of liver abscesses. The objective of this study was to utilize 16S ribosomal RNA amplicon sequence analyses to analyze the bacterial community composition of purulent material of liver abscesses of crossbred cattle (n = 24) and Holstein steers (n = 24), each fed finishing diet with or without tylosin. DNA was extracted and the V3 and V4 regions of the 16S rRNA gene were amplified, sequenced, and analyzed. The minimum, mean, and maximum sequence reads per sample were 996, 177,070, and 877,770, respectively, across all the liver abscess samples. Sequence analyses identified 5 phyla, 14 families, 98 genera, and 102 amplicon sequence variants (ASV) in the 4 treatment groups. The dominant phyla identified were Fusobacteria (52% of total reads) and Proteobacteria (33%). Of the top 25 genera identified, 17 genera were Gram negative and 8 were Gram positive. The top 3 genera, which accounted for 75% of the total reads, in the order of abundance, were Fusobacterium, Pseudomonas, and Bacteroides. The relative abundance, expressed as percent of total reads, of phyla, family, and genera did not differ (P > 0.05) between the 4 treatment groups. Generic richness and evenness, determined by Shannon–Weiner and Simpson’s diversity indices, respectively, did not differ between the groups. The UniFrac distance matrices data revealed no clustering of the ASV indicating variance between the samples within each treatment group. Co-occurrence network analysis at the genus level indicated a strong association of Fusobacterium with 15 other genera, and not all of them have been previously isolated from liver abscesses. In conclusion, the culture-independent method identified the bacterial composition of liver abscesses as predominantly Gram negative and Fusobacterium as the dominant genus, followed by Pseudomonas. The bacterial community composition did not differ between crossbred and Holstein steers fed finishing diets with or without tylosin.
Safety, Pharmacokinetics and Pharmacodynamics of Spectrum Yellow Oil in Healthy Participants
Authors: Peters Erica N , Mosesova Irina , MacNair Laura , Vandrey Ryan , Land M Hunter , Ware Mark A , Turcotte Cynthia , Bonn-Miller Marcel O
Published: March 2021

Due to a lack of published pharmacokinetic (PK) and/or pharmacodynamic (PD) data, decision-making surrounding appropriate dosing of cannabis used for medical purposes is limited. This multiple-dose study evaluated the safety, tolerability, PK and PD of Spectrum Yellow oil [20 mg/mL cannabidiol (CBD)/<1 mg/mL ∆9-tetrahydrocannabinol (THC)]. Participants (n = 43) were randomized to one of five groups: 120 mg CBD and 5.4 mg THC daily, 240 mg CBD and 10.8 mg THC daily, 360 mg CBD and 16.2 mg THC daily, 480 mg CBD and 21.6 mg THC daily or placebo. Study medication was administered every 12 h for 7 consecutive days. Treatment-emergent adverse events (TEAEs); plasma and urine concentrations of THC, CBD and metabolites; and self-reported subjective effects were collected. Nearly all TEAEs (44/45) were of mild or moderate severity; none was serious. The highest incidence of TEAEs (67%) was in the two higher-dose treatment groups. The highest number of TEAEs (17/45) occurred on the first treatment day. Steady-state plasma CBD concentrations were reached by Day 7. On Day 7, CBD exposure showed dose proportionality (AUC0–t slope = 1.03 [0.70, 1.36], Cmax slope = 0.92 [0.53, 1.31]). Most plasma THC concentrations were below the limit of quantification. Across Days 1 and 7, there were no consistent differences in subjective effects between placebo and active study medication. A prudent approach to improve tolerability with Spectrum Yellow oil might involve initial doses no higher than 240 mg total CBD and 10.8 mg total THC daily in divided doses, with titration upward over time as needed based on tolerability.
Investigation of a QuEChERS-Based Method for Determination of Polycyclic Aromatic Hydrocarbons in Rat Plasma by GC–MS
Authors: El Azab Noha F , Hotar Said F , Trabik Yossra A
Published: March 2021

Owing to the toxic effects of polycyclic aromatic hydrocarbons (PAHs) on humans and the environment, their sensitive biomonitoring is essential and significant. In this work, a sensitive, simple and rapid bioanalytical method was established for the simultaneous determination of 13 PAHs in rat plasma depending on QuEChERS (Quick, easy, cheap, effective and rugged method) as a preliminary step and gas chromatography–mass spectrometry (GC–MS) for identification. QuEChERS procedure was optimized where acetonitrile was employed for plasma samples extraction, which was further cleaned using primary secondary amine as the sorbent material. Optimization of GC–MS conditions was performed to produce optimum selectivity of the proposed method. The method was fully validated for rat plasma samples where recoveries, matrix effects, limit of quantitation (LOQ), linearity and precision were evaluated. Linearity range was 5–100 ng/mL for most of the 13 analytes. Average recoveries of the 13 PAHs ranged between 85.57% and 109.64% in fortified rat plasma with standard deviations <8.91 except for anthracene that showed 19.24. The limits of detection and LOQs for the 13 compounds ranged from 0.045 to 0.372 ppb and from 0.137 to 1.128 ppb, respectively. The established method was successfully implemented to perform a minor toxicokinetic study in intraperitoneally dosed rats (0.25 and 2 mg/kg in vegetable oil). The 13 PAHs were tracked in rat plasma samples for 6 h after administration, and most of the target compounds were recognized in plasma samples only at the higher dose.
Factors Associated With Pediatric Burn Clinic Follow-up After Emergency Department Discharge
Authors: Seegan Paige L , Tangella Kavya , Seivert Nicholas P , Reynolds Elizabeth , Young Andrea S , Ziegfeld Susan , Garcia Alejandro V , Hodgman Erica , Parrish Carisa
Published: March 2021

Attrition between emergency department discharge and outpatient follow-up is well documented across a variety of pediatric ailments. Given the importance of outpatient medical care and the lack of related research in pediatric burn populations, we examined sociodemographic factors and burn characteristics associated with outpatient follow-up adherence among pediatric burn patients. A retrospective review of medical records was conducted on patient data extracted from a burn registry database at an urban academic children’s hospital over a 2-year period (January 2018–December 2019). All patients were treated in the emergency department and discharged with instructions to follow-up in an outpatient burn clinic within 1 week. A total of 196 patients (Mage = 5.5 years; 54% male) were included in analyses. Average % TBSA was 1.9 (SD = 1.5%). One third of pediatric burn patients (33%) did not attend outpatient follow-up as instructed. Older patients (odds ratio [OR] = 1.00; 95% confidence interval [CI]: [0.99–1.00], P = .045), patients with superficial burns (OR = 9.37; 95% CI: [2.50–35.16], P = .001), patients with smaller % TBSA (OR = 1.37; 95% CI: [1.07–1.76], P = .014), and patients with Medicaid insurance (OR = 0.22; 95% CI: [0.09–0.57], P = .002) or uninsured/unknown insurance (OR = 0.07; 95% CI: [0.02–0.26], P = .000) were less likely to follow up, respectively. Patient gender, race, ethnicity, and distance to clinic were not associated with follow-up. Follow-up attrition in our sample suggests a need for additional research identifying factors associated with adherence to follow-up care. Identifying factors associated with follow-up adherence is an essential step in developing targeted interventions to improve health outcomes in this at-risk population.
A2
KRT15+ TUMOR CELLS AS PUTATIVE CANCER STEM CELLS IN ESOPHAGEAL CANCER.
Authors: Douchin J , Giroux V
Published: March 2021

Background

Esophageal cancer is a particularly deadly cancer with a 5-year survival rate of only 14% in Canada. Treatment resistance ascribed for at least 30% of the death. The acquisition of resistance to radio- and chemotherapy is mostly attributed to the presence of cancer stem cells (CSCs) and their persistence following classical treatments. CSCs are a subpopulation of tumor cells with high self-renewal and multipotent capacity which amongst others contribute to tumor heterogeneity. Our previous work identified Krt15+ esophageal cells as a rare and long-lived subpopulation of basal cells with higher self-renewal and multipotent capacities than other basal cells. Furthermore, preliminary observations suggest that Krt15+ cells could act as the cell-of-origin for ESCC, the most prevalent type of esophageal cancer worldwide. Though, we still ignore the role of Krt15+ cells in later stages of esophageal cancer such as treatment resistance and if therefore, they could act as CSC.

Aims

Determine if Krt15+ cells act as CSCs in ESCC patients and if they could contribute to treatment resistance.

Methods

To do so, we used Krt15-CrePR1;R26mT/mG mice treated with the carcinogen 4 Nitroquinoline-1-oxide (4NQO) in their drinking water for 16 weeks to induce ESCC. Twelve weeks following the beginning of 4NQO treatment, we induced Cre recombination with RU486, a PR1 agonist, leading to GFP expression specifically in Krt15+ cells. Following 4NQO treatment, mice were put back on normal water for 8 to 12 weeks allowing tumors to grow. At euthanasia, esophageal tumor cells were FACS sorted to isolate Krt15+ (GFP+) and Krt15- (GFP-) cells, which were then grown as tumoroids.

Results

We first validated that 4NQO successfully induced the formation of esophageal lesions in our model, which comprises Krt15+ and Krt15- tumor cells. Tumoroids were then successfully derived from these FACS-sorted cell populations. We demonstrated the increase of CSC-like cells within Krt15+ tumoroids compared to Krt15- tumoroids by measuring the presence of CD44highCD24high cells, two well-known CSC markers, by flow cytometry. Interestingly, Krt15+ and Krt15- tumoroids are histologically distinct. As observed for normal cells, Krt15+ tumoroids appeared as more multipotent and heterogenous than Krt15- tumoroids. Furthermore, Krt15+ tumoroids display higher hyperplasia than Krt15- tumoroids suggesting that Krt15+ tumor cells are functionally distinct from Krt15- tumor cells.

Conclusions

Krt15+ tumoroids display higher CSC content and hyperplastic capacity suggesting their potential role in esophageal cancer. With this project, we aim to highlight the role of Krt15+ cells in treatment resistance and put forward new targets to overcome this deadly issue in ESCC patients.

Funding Agencies

CAGCanada research chair TIER 2
A5 GM-CSF AUTOANTIBODIES: PREDICTORS OF CROHN’S DISEASE DEVELOPMENT AND A NOVEL THERAPEUTIC APPROACH
Authors: Tai S , Remark R , Laface I , Del Valle D M , Torres J , Rahman A , Laird R M , Porter C , Riddle M , Murray J a , Choung R , Sato T , Plevy S , Merad M , Colombel J , Gnjatic S , Mortha A
Published: March 2021

Background

Crohn’s disease (CD) is a heterogenous, chronic inflammatory disorder driven by a combination of genetic, environmental, and microbiota-dependent risk factors. Mononuclear phagocytes (MNP) are crucial cells that maintain intestinal homeostasis. An important cytokine for MNP survival and function is granulocyte-macrophage colony stimulating factor (GM-CSF). Interestingly, several studies reported CD-associated genetic risk variants within the GM-CSF receptor and its downstream signaling components. Furthermore, high titers of autoantibodies specific to GM-CSF can be detected in CD patients. Taken together, this data suggests an important role for GM-CSF in abrogation of CD development in a subgroup of patients.

Aims

This study sought to investigate the function of GM-CSF autoantibodies in CD.

Methods

We retrospectively quantified and characterized GM-CSF autoantibodies in sera of 220 CD, 200 ulcerative colitis (UC) patients, and 220 healthy controls (HC) sampled at 3 time points prior to disease diagnosis and one time point after diagnosis. ELISA was used to determine GM-CSF autoantibody titers and isotypes followed by in vitro multiplexed mass cytometry (CyTOF) neutralization assays on peripheral blood mononuclear cells. Flow cytometry and CyTOF were used to map the profile of immune cells isolated from inflamed and non-inflamed CD mucosa.

Results

Our data demonstrates that GM-CSF autoantibodies are specific to CD, significantly elevated up to 7 years prior to diagnosis of disease, and correlate with disease location, severity, and complications at the time of diagnosis. Moreover, in contrast to GM-CSF autoantibodies in pulmonary alveolar proteinosis patients, CD-associated autoantibodies neutralize GM-CSF via specific recognition of post-translational modifications (PTM), affecting MNP function. Removal of PTM enabled GM-CSF to escape autoantibody binding and restored MNP response to GM-CSF in the presence of neutralizing antibodies, indicating a potential therapeutic avenue. Furthermore, we identified group 3 innate lymphoid cells (ILC3) as a major source of GM-CSF in the healthy intestinal tract, suggesting intriguing crosstalk of MNP and ILC3 across the GM-CSF-GM-CSFR axis.

Conclusions

Our results identify GM-CSF autoantibodies as predictive serological biomarker for CD in a subgroup of patients presenting with severe and complicated form of disease at the time of diagnosis. The presence of GM-CSF autoantibodies precedes the onset of CD by several years and likely abrogates homeostatic immune cell crosstalk involving ILC3 and MNP, suggesting the development of a pre-diseased state in CD patients.

Funding Agencies

CIHRDr. Edward Ketchum Graduate Scholarship
A7 AN INULIN-TYPE FRUCTAN ENRICHED EXCLUSIVE ENTERAL NUTRITION FORMULA MODULATES THE GUT MICROBIOME AND PROMOTES EXPANSION OF ANTI-INFLAMMATORY T CELL SUBSETS TO SUPPRESS COLITIS
Authors: Healey G R , Tsai K , Lisko D , Vallance B , Jacobson K
Published: March 2021

Background

Exclusive enteral nutrition (EEN), a nutritionally complete fiber-free enteral formula, is the gold standard therapy for newly diagnosed children with Crohn’s disease (CD) but this therapy is not routinely used in pediatric ulcerative colitis patients due to lower efficacy in this subgroup. EEN therapy leads to high remission rates, however it also leads to a dysbiotic gut microbiota profile and disease relapse occurs in 60–80% of CD patients within 12 months of EEN discontinuation. Little is known about the mechanisms underlying the actions of EEN. Notably, previous studies have demonstrated that prebiotics, such as inulin-type fructans (IN), can beneficially modulate the gut microbiome, increase butyrate production and reduce inflammation by leading to anti-inflammatory T cell (i.e. FOXP3+IL10+ CD4+) expansion. To date, the effects of an IN enriched EEN (EEN IN) have not been studied.

Aims

To examine the effects of EEN vs EEN IN on colitis development, the gut microbiome and CD4+ T cell subsets using an adoptive T cell transfer model of colitis.

Methods

Mice were split into four groups: 1) Control – normal chow + PBS (n=13; negative control), 2) Chow – normal chow + naive T cell transfer (n=13; positive control), 3) EEN – Ensure Plus® + naive T cell transfer (n=13) and 4) EEN IN – Ensure Plus® with 3% IN + naive T cell transfer (n=13). Naïve T cells (or PBS) were transferred into TCR-b deficient mice and each group was started on their subsequent diets. The naïve T cells will expand into anti- or pro-inflammatory T cells subsets to either cause or suppress colitis in a gut microbiome dependent manner. Body weight and disease activity were monitored for 5-weeks. At the end of the experiment, spleen weights and colon lengths were recorded. Spleen and mesenteric/colonic lymph nodes (MLN) were collected for T cell subset analysis using flow cytometry. Gut microbiota differences were assessed using ddPCR. Short-chain fatty acid levels were analyzed using gas chromatography. The histopathology of the distal colon was scored.

Results

Mice fed EEN IN showed a reduction in colonic shortening (p<0.001) and histology scores (p=0.0088) compared to EEN mice, and reduced disease activity (p=0.0046) compared to Chow mice. Moreover, EEN IN mice showed a higher expansion of FOXP3+IL10+ CD4+ T cells in the MLN (p=0.0424) and spleen (p=0.0088). EEN IN also led to higher butyrate, Bifidobacterium and Bacteroides concentrations compared to EEN (p=0.0113, p=0.0063, p=0.0224; respectively) and Chow (p=0.0252, p=0.0042, p=0.0416; respectively).

Conclusions

EEN IN lead to superior outcomes compared to EEN and Chow. These results provide evidence to support undertaking a clinical trial utilizing EEN IN in pediatric inflammatory bowel disease patients.

Funding Agencies

Michael Smith Foundation for Health Research
A8 DIETARY TRYPTOPHAN MODULATES KYNURENINE AND INDOLE PRODUCTION IN HEALTHY INDIVIDUALS
Authors: Rueda G H , Causada-Calo N , Borojevic R , Nardelli A , Constante M , Loonen L , Wells J , Sokol H , Verdu E , Bercik P
Published: March 2021

Background

Tryptophan is an essential amino acid that is transformed by host and gut microbial enzymes into multiple bioactive metabolites that regulate immunity, mood and circadian rhythms. In particular, indoles, produced by gut bacterial metabolism of tryptophan, have recently gained central attention. Indoles are activators of the aryl hydrocarbon receptor (AhR), which is crucial for the maintenance of intestinal homeostasis and immunity. Tryptophan supplementation in fortified foods have been advocated to prevent chronic inflammatory conditions, from autism to chronic inflammation. However, whether dietary tryptophan supplementation affects immune function, tryptophan metabolic pathways and gastrointestinal symptoms in healthy subjects, is unknown.

Aims

To assess whether tryptophan supplementation, in healthy subjects on a low tryptophan diet, induces changes in microbiota-derived metabolites (indoles), host cytokine production or gut symptoms.

Methods

We performed a randomized, double blind, placebo-controlled, crossover study in 20 healthy individuals, between 18 and 75 years old, following a regular diet. Subjects were instructed to start a standardized low tryptophan diet and were randomly assigned to a 3-week tryptophan supplement (3gr/day) or placebo. After a 2-week washout period, subjects were crossed over to the opposite 3-week intervention arm. Self-administered questionnaires (GSRS, DASS21 and HADS) were used to assess gastrointestinal symptoms and mood/anxiety/stress. Stool, urine and blood samples were collected to measure tryptophan metabolites (kynurenine pathway and indoles) and cytokines.

Results

Supplementation of tryptophan was well tolerated and no changes in gastrointestinal symptoms or mood/anxiety were found. Compared with placebo, tryptophan supplementation increased urinary and plasma levels of indoleamine 2,3-dioxygenase (p= 0.002 and p= 0.02, respectively), a key enzyme in the kynurenine pathway, and of several indoles (p= 0.0008 and p= 0.01, respectively), suggestive of activation of microbial and host metabolic pathways. However, there were no measurable changes in the host cytokine production. There was a positive correlation between fecal kynurenine levels and anxiety and depression scores, suggesting that microbial metabolites may impact host behavior in humans.

Conclusions

Dietary tryptophan supplementation in healthy individuals was safe and had a measurable effect on microbial and host metabolism, mainly kynurenine and indole pathways, with known immunomodulatory properties. Although no effects on cytokine production were found, further studies are warranted to investigate tryptophan supplementation in disorders with altered AhR pathway, such as inflammatory bowel disease, metabolic syndrome and celiac disease.

Funding Agencies

None
A32 EMPAGLIFOZIN IMPROVES GASTROINTESTINAL INFLAMMATION IN A MOUSE MODEL OF COLITIS
Authors: Madsen K , Dang H , Hotte N , Mocanu V , Ferdaoussi M , Thiesen A , Dyck J
Published: March 2021

Background

Empagliflozin (EMPA) is a highly selective sodium glucose cotransporter-2 (SGLT2) inhibitor and is increasingly being utilized as an antihyperglycemic agent in the management of type 2 diabetes. Interestingly, it has been demonstrated in human trials that EMPA treatment exerts potent cardioprotective effects by reducing cardiac inflammation independently of glycemic control. Further, EMPA has also been shown to suppress LPS-induced renal and systemic inflammation in an animal model. Based on these findings, we hypothesized that EMPA treatment may also be effective in reducing gut inflammation.

Aims

The aim of this study was to examine the effects of treatment with EMPA on gastrointestinal inflammation in an animal model of inflammatory bowel disease and to determine mechanistic insights regarding its direct effects on gut cytokine secretion.

Methods

Adult male and female IL-10-/- mice with established colitis were treated with a daily gavage of EMPA (10mg/kg; n=10) or vehicle (n=10) for 14 days. Disease activity was assessed by measurement of mouse weight, colonic weight and length, histological score, cytokine levels in colonic homogenate and lipocalin-2 levels in stool. To examine for possible direct effects of EMPA, colonic explants from wild-type (n=8) and IL-10-/- (n=8) mice were incubated with increasing doses of EMPA (0.1–5 µM) ± LPS (10µg/ml) for 2 hours and tissue levels of IL-1β and TNFα protein measured by ELISA.

Results

After 14 days EMPA treated IL-10-/- mice had a significant improvement in colonic inflammation as evidenced by decreased colonic weight to length ratio (p=0.019), decreased fecal lipocalin-2 (p=0.03), as well as decreased enterocyte injury (p=0.01), decreased lamina propria neutrophils (p=0.01) and decreased total histological score (p=0.006). EMPA treated mice also maintained their weight over the 14 days while untreated mice continued to lose weight (p=0.04). There were no significant differences in colonic homogenate levels of TNFα, IL-1β, or IL-6 or in blood glucose levels between EMPA-treated mice and controls. In addition, EMPA did not suppress levels of basal or LPS-induced TNFα and IL-1β in colonic explants from either wild-type or IL-10-/- mice suggesting that the beneficial effects in IL-10-/- mice were not due to direct effects of EMPA on colonic TNFα or IL-1β cytokine levels.

Conclusions

EMPA treatment dramatically improved histologic and fecal inflammatory markers and maintained body weight in adult IL-10-/- mice with established colitis. These findings suggest further investigations into the effects of EMPA in treating gut inflammation are warranted.

Funding Agencies

CAG, CIHR
A34 ANTIBIOTIC TREATMENT AND ORAL IRON SUPPLEMENTATION SHAPE THE COMPOSITION, RECOVERY AND FUNCTION OF THE GUT MICROBIOTA
Authors: Cuisiniere T , Oliero M , Hajjar R , Calve A , Fragoso G , Santos M M
Published: March 2021

Background

Colorectal cancer (CRC) induces anemia in a large proportion of patients and is usually treated with oral iron supplementation. Surgery, the main treatment for CRC, is routinely accompanied by prophylactic antibiotics to avoid infection. However, the combined effect of antibiotics and luminal iron in the gut on the microbiota and intestinal homeostasis remains unknown.

Aims

We aim to characterize the dynamics of gut microbiota composition and recovery from antibiotic exposure under iron-sufficient and iron-supplemented diets in mice. We will investigate how microbial shifts induced by antibiotics and iron influence the function of the gut microbiota and metabolites in the gut.

Methods

Mice were subjected to antibiotic treatment with different concentrations of dietary iron. The composition of the gut microbiota and its recovery after these interventions were assessed in stool samples by 16S rRNA sequencing before and after antibiotic exposure and during the recovery period. Gut microbiota functions were inferred by using the PICRUSt2 prediction tool, and short chain fatty acid (SCFA) concentration in feces were assessed by liquid-chromatography mass spectrometry.

Results

Recovery from antibiotics under high luminal iron concentration shifted the gut microbiota toward a Bacteroidetes phylum-dominant composition. Four bacterial species characterized as CRC markers and/or CRC initiators were significantly more abundant, and nitrogen and pentose phosphate metabolism were higher after recovery under oral iron supplementation. Antibiotic exposure induced a long-term increase in SCFAs linked to gut inflammation, propionate and succinate, and was independent of luminal iron concentration. For mice recovering from antibiotics under high luminal iron concentration, they showed a lack of recovery in baseline levels of butyrate, a SCFA that inhibits cancer cell proliferation in the gut.

Conclusions

Gut microbiota recovery from antibiotic exposure under oral iron supplementation is frequent in CRC patients, but is also common in the general population. This study identifies possible deleterious effects of the concomitance of these two disruptive agents of the gut microbiota and may lead to modifications in the management of anemia in patients with CRC.

Funding Agencies

CIHR Bourse de Mérite Rougier-Armandie en recherche médicale de la Faculté de médecine
A42 INULIN PROMOTES POLYPS DEVELOPMENT IN APC
MIN/+ MOUSE COLONIZED BY ESCHERICHIA COLI NC101
Authors: Oliero M , Cuisiniere T , Hajjar R , Fragoso G , Calve A , Santos M M
Published: March 2021

Background

Colibactin is a genotoxin that induces double-strand DNA breaks and is produced by Escherichia coli strains harboring the pks island. Human and animal studies have shown that colibactin-producing gut bacteria promote carcinogenesis and facilitate the progression of colorectal cancer through cellular senescence and chromosomal abnormalities.

Aims

In this study, we investigated the impact of inulin, a prebiotic able to modulate bacterial metabolism, in a colorectal cancer model, ApcMin/+mice, colonized by colibactin-producing E. coli strain NC101.

Material & methods

Apc Min/+ mice were subjected to oral gavage with PBS (control) or 108 cfu of E. coli NC101 after a week of receiving a 2% dextran sulfate sodium solution in drinking water. Mice were fed a diet supplemented with 10% cellulose (control) or 10% inulin for 4 weeks. During necropsy, the number of polyps in the duodenum, jejunum, ileum, and colon was counted. Tumors in the colon were graded and the erythroid parameters were measured.

Results

We showed that the inulin diet increased the number of polyps in the ileum compared to cellulose. Moreover, mice colonized with E. coli NC101 and on the inulin diet presented severe anemia associated with an increasing number of polyps in the duodenum, jejunum, and ileum compared to mice supplemented with cellulose.

Conclusions

Our results suggest that, in vivo, inulin promotes polyp development in the small intestine of ApcMin/+ mice colonized by pks+ E. coli strain NC101.

Funding Agencies

CIHRNSERC
A65 ENDOSCOPIST-TARGETED INTERVENTIONS TO OPTIMIZE ADENOMA DETECTION RATE - A SYSTEMATIC REVIEW AND META-ANALYSIS
Authors: Arora A , McDonald C , Iansavitchene A , Brahmania M , Sey M
Published: March 2021

Background

Adenoma detection rate (ADR) has emerged as the strongest quality assurance metric that has consistently been shown to be inversely associated with the development of colorectal cancer after colonoscopy. Unfortunately, marked variability in ADR exists among endoscopists. A multitude of interventions targeted at endoscopists to optimize their ADR have been reported, including but not limited to withdrawal time, in room observers, physician report cards, and quality improvement and training programs. However, it is unclear which of them are truly effective.

Aims

We performed a systematic review and meta-analysis of the literature to evaluate the effectiveness of endoscopist-targeted interventions to improve adenoma detection rate (ADR) or polyp detection rate (PDR).

Methods

Systematic searches of major databases were conducted through to March 2018 to identify potentially relevant studies. Both randomized controlled trials and observational studies were included. Data for ADR and PDR were analyzed on the log-odds scale using a random-effects meta-analysis model using restricted maximum likelihood (with Mantel-Haenszel fixed-effect meta-analysis used for fewer than 4 studies). Statistical effect-size heterogeneity was assessed using a Chi2 test and quantifying the relative proportion of variation using the I2 statistic. Publication bias was assessed by the Harbord regression test.

Results

From 4299 initial studies, 24 were included in the systematic review and 13 were included in the meta-analysis representing a total of 55,090 colonoscopies. Physician report card interventions (7 studies) and withdrawal time focused interventions (6 studies) were meta-analyzed. The pooled odds ratio for ADR for report card interventions was 1.31 (95% CI: 1.15, 1.50; p<0.0001), favoring report cards to detect more adenomas. Statistical heterogeneity was detected with substantial relative effect-size variability (Chi2, p<0.0001; I2=80.1%). No statistical evidence of publication bias was found. 6 studies reported data for PDR using withdrawal time focused interventions, with 3 of these reporting data on ADR. The pooled odds ratio for ADR was 1.02 (95% CI: 0.86, 1.22; p=0.81) and for PDR was 1.07 (95% CI: 0.88, 1.31; p=0.51) which were not statistically significant. Statistical heterogeneity was detected in both groups (Chi2, p<0.001; I2=82.2% for ADR and I2=89.4% for PDR) and there was statistical evidence of publication bias. Figures 1 and 2 represent Forest plots for the effect of pre-and post-report card and withdrawal time focused interventions on ADR.

Conclusions

Our study provides evidence that the distribution of colonoscopy quality report cards to physicians significantly improves overall ADR and should strongly be considered as part of quality improvement programs aimed at optimizing colonoscopy performance.

Funding Agencies

None