Commissioning of a solid tank design for fan-beam optical CT based 3D radiation dosimetry

Objective.Optical computed tomography (CT) is one of the leading modalities for imaging gel dosimeters used in the verification of complex radiotherapy treatments. In previous work, a novel fan-beam optical CT scanner design was proposed that could significantly reduce the volume of the refractive index baths that are commonly found in optical CT systems. Here, the proposed scanner has been manufactured and commissioned.Approach.Image reconstruction is performed through algebraic reconstruction technique and iterated using the fast iterative shrinkage-thresholding algorithm (FISTA) algorithm. Ray tracing for algebraic reconstruction was performed using an in-house developed ray tracing simulator. A set of Sylgard® 184 phantoms were created to commission spatial resolution, geometric deformity, contrast-to-noise ratio (CNR), and scan settings.Main Results.The scanner is capable of a 0.929 mm-1spatial resolution, observed at 200 iterations, although the spatial resolution is highly dependent on the number of iterations. The geometric distortion, measured by scanning a needle phantom with the prototype scanner as well as a conventional x-ray CT was found to be within <0.25 mm. The CNR was found to peak between 65 and 190 occurring between 50 and 100 iterations and was highly dependent on the region chosen for background noise calculation. The proposed scanner is capable of scanning and reading out slices in less than 1 min per slice.Significance.This work displays the viability of a fan-beam optical CT scanner with minimal index matching using ray-traced algebraic reconstruction.

Researching COVID to Enhance Recovery (RECOVER) adult study protocol: Rationale, objectives, and design

IMPORTANCE

SARS-CoV-2 infection can result in ongoing, relapsing, or new symptoms or other health effects after the acute phase of infection; termed post-acute sequelae of SARS-CoV-2 infection (PASC), or long COVID. The characteristics, prevalence, trajectory and mechanisms of PASC are ill-defined. The objectives of the Researching COVID to Enhance Recovery (RECOVER) Multi-site Observational Study of PASC in Adults (RECOVER-Adult) are to: (1) characterize PASC prevalence; (2) characterize the symptoms, organ dysfunction, natural history, and distinct phenotypes of PASC; (3) identify demographic, social and clinical risk factors for PASC onset and recovery; and (4) define the biological mechanisms underlying PASC pathogenesis.

METHODS

RECOVER-Adult is a combined prospective/retrospective cohort currently planned to enroll 14,880 adults aged ≥18 years. Eligible participants either must meet WHO criteria for suspected, probable, or confirmed infection; or must have evidence of no prior infection. Recruitment occurs at 86 sites in 33 U.S. states, Washington, DC and Puerto Rico, via facility- and community-based outreach. Participants complete quarterly questionnaires about symptoms, social determinants, vaccination status, and interim SARS-CoV-2 infections. In addition, participants contribute biospecimens and undergo physical and laboratory examinations at approximately 0, 90 and 180 days from infection or negative test date, and yearly thereafter. Some participants undergo additional testing based on specific criteria or random sampling. Patient representatives provide input on all study processes. The primary study outcome is onset of PASC, measured by signs and symptoms. A paradigm for identifying PASC cases will be defined and updated using supervised and unsupervised learning approaches with cross-validation. Logistic regression and proportional hazards regression will be conducted to investigate associations between risk factors, onset, and resolution of PASC symptoms.

DISCUSSION

RECOVER-Adult is the first national, prospective, longitudinal cohort of PASC among US adults. Results of this study are intended to inform public health, spur clinical trials, and expand treatment options.

REGISTRATION

NCT05172024.

Trajectories of Antiretroviral Therapy Adherence and Virologic Failure in Women With HIV in the United States

BACKGROUND

Women with HIV (WHIV) in the United States face many challenges with adherence to antiretroviral therapy (ART), and suboptimal adherence often leads to virologic failure. This study aimed to determine the association between ART adherence trajectories and the risk of virologic failure.

METHODS

We included WHIV (aged 18 years or older) enrolled in the Women's Interagency HIV Study in the United States from April 2014 to September 2019 who had at least 2 consecutive measurements of HIV RNA and ≥3 measurements of self-reported adherence. Group-based trajectory modeling was used to identify adherence trajectories. Cox proportional hazard ratios were used to measure the association.

MAIN OUTCOME MEASURE

Virologic failure was defined as HIV RNA ≥200 copies/mL at 2 consecutive visits.

RESULTS

We included 1437 WHIV (median age 49 years). Of all women, 173 (12.0%) experienced virologic failure. Four adherence trajectories were identified, namely "consistently high" (26.3%), "moderate increasing" (9.5%), "moderate decreasing" (30.6%), and "consistently low" (33.5%). Women in the consistently low adherence group consumed alcohol and experienced depression more than other groups. Compared with the "consistently high" trajectory, the risk of virologic failure was higher among women with "consistently low" [adjusted hazard ratio (aHR) 2.8; 95% confidence interval (CI): 1.6 to 4.9; P < 0.001] and "moderate decreasing" adherence trajectories (aHR 1.8; 95% CI: 1.0 to 3.2; P = 0.04), but it was similar to those with "moderate increasing" adherence trajectory (aHR 1.0; 95% CI: 0.4 to 2.5; P = 0.94).

CONCLUSIONS

Adherence to ART remains a challenge among WHIV. Multilevel behavioral interventions to address poor adherence, alcohol consumption, and depression are needed.

Dual trajectories of antiretroviral therapy adherence and polypharmacy in women with HIV in the United States

BACKGROUND

Polypharmacy, using five or more medications, may increase the risk of nonadherence to prescribed treatment. We aimed to identify the interrelationship between trajectories of adherence to antiretroviral therapy (ART) and polypharmacy.

METHODS

We included women with HIV (aged ≥ 18) enrolled in the Women's Interagency HIV Study in the United States from 2014 to 2019. We used group-based trajectory modeling (GBTM) to identify trajectories of adherence to ART and polypharmacy and the dual GBTM to identify the interrelationship between adherence and polypharmacy.

RESULTS

Overall, 1,538 were eligible (median age of 49 years). GBTM analysis revealed five latent trajectories of adherence with 42% of women grouped in the consistently moderate trajectory. GBTM identified four polypharmacy trajectories with 45% categorized in the consistently low group.

CONCLUSIONS

The joint model did not reveal any interrelationship between ART adherence and polypharmacy trajectories. Future research should consider examining the interrelationship between both variables using objective measures of adherence.

A266 DIET-BASED THERAPIES FOR INTESTINAL DYSFUNCTION INDUCED BY CLOSTRIDIOIDES DIFFICILE INFECTION

Background

Chronic gut dysfunction occurs in up to 25% of patients following antibiotic-treated C. difficile infection (CDI). We developed a humanized mouse model in which germ free mice colonized with microbiota from patients with severe constipation post-CDI developed slow colonic transit, as a result of damage to the Interstitial Cells of Cajal (ICC) network by pro-inflammatory macrophages. Colonic transit, immune activation and the ICC network normalized after fecal microbiota transplantation using samples from healthy mice, as well after treatment with psyllium fiber. Here we explored the long-term effects of psyllium and evaluated the therapeutic potential of pectin and quercetin in this model.

Purpose

1) To investigate the time course of the beneficial effect of psyllium on colonic motility.

2) To explore possible therapeutic properties of flavonoids and pectin.

Method

Germ-free mice were colonized with microbiota from the post-CDI (PCDI) patient or healthy controls (HC). After 3 weeks, the mice were fed for 4-5 weeks with a control diet or diets with 15% psyllium (PSY), 10% pectin (PCT) or 0.05% quercetin (QCT). To evaluate time course of PSY on motility, control diet was administered for 3-weeks following PSY treatment. The bead expulsion test was used to assess colonic motility. Stool samples were collected for microbial profiling, and short and branched-chain fatty acids (SCFA/BCFA) analysis. Macrophages morphology and counts, and ICC network structure were evaluated by immunohistochemistry.

Result(s)

Compared to HC microbiota, colonization with post-CDI microbiota induced slow colonic transit in recipient mice, and this was normalized by PSY (n=13; p=0.02). The benefit of PSY was transient as colonic transit slowed following discontinuation of PSY (p=0.001). The changes in colonic transit were paralleled by switch in macrophages phenotype and damage to the ICC network. Additionally, discontinuation of PSY resulted in a return of microbial diversity (p< 0.001), SCFA/BCFA levels (acetic and propionic acid/ iso-butyric and valeric acid) and specific bacterial species abundances, to values seen in untreated mice colonized with post-CDI microbiota. Microbial analysis predicted potential pathways involved in macrophage polarization, including the synthesis of SCFA/BCFA, degradation of inositol and production of acetylglucosamine.

PCT also normalized slow intestinal transit in mice colonized with post-CDI microbiota (p=0.003), restored phenotype of infiltrating macrophages, and improved the structural integrity of the ICC network. In contrast, QCT failed to improve gut dysfunction in PCDI mice.

Conclusion(s)

Our results suggest that the beneficial effects of psyllium in this model are transient. Dietary pectin, but not quercetin, may also serve as a novel treatment strategy to restore colonic motility and immune homeostasis in humans with severe constipation post-CDI.

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Other

Please indicate your source of funding;

W. Garfield Weston Foundation

Disclosure of Interest

None Declared

A30 EPITHELIAL FUNCTION OF THE CIRCADIAN CLOCK GENE, BMAL1, IS NECESSARY FOR COLONIC REGENERATION

Background

The circadian clock is a self-sustained molecular oscillator which drives 24-hour physiological rhythms. It consists of the genes Bmal1 and Clock that positively regulate Cry and Per, their negative regulators, resulting in a 24-hour transcription/translation feedback loop. Shift work, which causes disruptions to 24-hour physiological rhythms, has been shown to lead to an increased incidence of inflammatory bowel disease (IBD). We have previously established that mice lacking the non-redundant circadian regulator, Bmal1, exhibit more severe colitis compared to controls.

Purpose

This study aims to investigate the epithelial function of Bmal1 in colonic regeneration during colitis.

Method

In order to assess the cell-specific role of the clock, we tested the regenerative effects of Bmal1 in intestinal epithelial tissue using Vil^+/+;Bmal1^flox/flox (control) and Vil^Cre/+;Bmal1^flox/flox (conditional mutant) mice. Dextran Sulfate Sodium (DSS) was applied to induce acute colitis. Disease progression was evaluated during colitis and during recovery upon removal of DSS treatment. We hypothesized that the absence of a functional circadian clock disrupts effective proliferation and regeneration of intestinal epithelial cells during colitis remission.

Result(s)

Vil^+/+;Bmal1^flox/flox control and Vil^Cre/+;Bmal1^flox/flox conditional mutant mice exhibit no significant differences in disease severity or tissue histopathology during colitis. However, after the removal of DSS, Vil^Cre/+;Bmal1^flox/flox conditional mutants show increased total lesions and overall inflammation, decreased crypt density as well as a higher propensity of hyperplastic crypts in the tissue. Regenerative ability of the colon is decreased in conditional mutants: phosphorylated-histone H3 and Ki67 show persistent increases in mitosis and overall proliferation near ulcerated lesions. This suggests that, while controls complete the regenerative response, conditional mutants fail to recover from colitis and show inefficient regeneration when Bmal1 is disrupted in intestinal epithelial cells.

Conclusion(s)

Our results support a critical role for Bmal1 in intestinal epithelial cells during post-colitis regeneration and recovery.

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CIHR, Other

Please indicate your source of funding;

OGS, Crohn's & Colitis Canada

Disclosure of Interest

None Declared

A62 IDENTIFICATION OF SPECIFIC COLONIC DEEP MUSCLE LAYER MACROPHAGES SUBSETS BY THE CD64 (FCΓRI) MARKER

Background

Although intestinal muscle layer macrophages have been suggested to play an important role in the colonic transit by interacting with the myenteric plexus neurons, they have not been fully characterized. CD64 (FcγRI) is one of the most generally used markers for intestinal macrophages, but several studies suggested existence of a subpopulation of macrophages that lack CD64. In addition, the muscle layer macrophage subsets currently identified are considered to be same in the small intestine and colon, although this has not been formally tested.

Purpose

In this study, we aim to identify and characterize the subsets of muscle layer macrophages by CD64 marker. We hypothesize that colon specific CD64-macrophages have a different role from CD64+ conventional macrophages.

Method

The muscle layers of small intestine (ileum) and colon were separated from SPF mice and cells from each muscle layer were analyzed by flow cytometry and fluorescent staining. The muscle layer macrophages were gated withCD45+, F4/80+, CD11b+ and Ly6c-, and analyzed with CD64 and MHCⅡmarkers by flow cytometry. In additional experiments, fluorescent staining with CD64 and F4/80 was assessed in whole-mount tissue of the separated muscle layer.

Result(s)

Within the macrophage population from the colon muscle layer, we found not only CD64+ cells, a conventional marker of macrophage, but also CD64- cell population (CD45+, F4/80+, CD11b+, Ly6c-). However, in the small intestine, this CD64- cell population was barely detectable. In addition, colonic CD64+ cells had mostly high expression of MHCⅡ marker, while CD64- cells had low expression of MHCⅡ. A similar pattern was found when we examined intestinal and colonic tissues by immunofluorescent staining.

Conclusion(s)

We identified a colon-specific CD64- subset of macrophage in muscle layer. Additional experiments are needed to characterize their immunomodulatory properties.

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None

Disclosure of Interest

None Declared

CLIINICAL PRACTICE

A45 FIBER-FREE DIET REDUCES BACTEROIDES ABUNDANCE AND PREVENTS MUCUS DEGRADATION IN MICE COLONIZED WITH MICROBIOTA FROM PATIENTS WITH GENERALIZED ANXIETY DISORDER

Background

Generalized anxiety disorder (GAD) is a debilitating condition with a lifetime prevalence of 4-7% worldwide. We have previously found that compared to healthy controls, GAD patients had lower reported fiber intake, increased gastrointestinal symptoms; and enrichment of Bacteroides genus as well as carbohydrate metabolism pathways (as determined by PICRUSt2, correlated to Bacteroides abundance). Bacteroides are known for its ability to degrade a wide variety of host polysaccharides, such as the intestinal mucus, which could lead to local and systemic inflammation. In this regard, GAD patients had higher C-reactive protein (CRP) compared to healthy controls (p=0.049).

Purpose

To investigate whether a fiber-free diet could decrease Bacteroides abundance and prevent damage of the mucus layer reducing anxiety-behavior in mice with GAD microbiota.

Method

Two germ-free NIH Swiss mouse breeding pairs were colonized with GAD microbiota using patients’ stool samples and kept on either fiber-free or 10 % inulin (fiber) diet. Offspring were weaned at week 3 and psychometric tests were performed at 10 weeks of age. After sacrifice, samples for histology (mucus layer thickness determination), blood (CRP ELISA determination) and stool (Illumina 16S rRNA gene sequencing) were collected. The microbiota data was analyzed following the pipelines of dada2 and by mean comparisons, correlation, AncomBC using R software (v.1.2.1335). Multiple comparison results were corrected allowing 5% of FDR.

Result(s)

Beta diversity analysis showed that parent and offspring’s (n=24 fiber-supplemented and n=14 fiber-free groups) microbiota was similar to the GAD donor. The most differentially abundant bacterial taxon was Bacteroides uniformis, which was decreased in the fiber-free group (p.adj= 0.003). Furthermore, fiber-free diet reduced the overall Bacteroides abundance by half compared to the donor and fiber-supplemented mice group. This led to a thickening (p.adj=0.027) of the mucus layer, increasing from 30 µm (fiber-supplemented diet) to 60 µm in the fiber-free diet group. B. uniformis was negatively correlated to the mucus layer thickness (R= -0.81; p.adj=0.26), although not statistically significant, likely due to a low n number (n=4). We only found a statistical trend for higher CRP levels and anxiety-like behavior in the fiber-supplemented group. This might be because fiber supplementation has several beneficial effects that can counteract the proposed increase in anxiety-like behavior fromBacteroides. Despite that, we found a significant correlation between B. uniformis and time mice spent in the dark (indicative of anxiety-like behavior) in the light preference test.

Conclusion(s)

Our data suggests that Bacteroides abundance, specifically Bacteroides uniformis, contributes to the degradation of the mucus layer and potentially triggers low grade gut inflammation and anxiety-like behavior.

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CIHR

Disclosure of Interest

None Declared

A19 INVESTIGATING MECHANISMS THAT DRIVE SYMPTOMS IN IRRITABLE BOWEL SYNDROME PATIENTS WITH PERCEIVED GLUTEN SENSITIVITY

Background

Patients with irritable bowel syndrome (IBS) often report gastrointestinal symptoms after consuming wheat and gluten-containing foods. It is, however, unclear whether gluten is the main driver of symptoms, as other immunogenic peptides, such as amylase trypsin inhibitors (ATI), poorly digestible fiber (inulin, part of FODMAP) or even the nocebo effect may contribute to symptom generation.

Purpose

To evaluate whether whole wheat containing ATIs and/or purified gluten trigger gastrointestinal symptoms compared to nocebo in patients with IBS adopting a gluten-free diet (GFD).

Method

We conducted a double-blind, randomized, nocebo-controlled crossover study in adult IBS patients (Rome IV criteria) who previously perceived improvement of symptoms while on a GFD. The study was approved by the Hamilton Research Ethics Board (HiREB #4367). Participants were challenged for 7 days with whole wheat, purified gluten, and nocebo (gluten-free flour) added to low FODMAP cereal bars. Each challenge was followed by a 2-week washout. Patients remained on a GFD throughout the study, diet adherence was assessed by a dietitian and stool gluten immunogenic peptides (GIP; Biomedal). Gastrointestinal symptoms were assessed by IBS Symptom Severity Score (IBS-SSS); increases >50 points were considered a significant worsening. Blood samples were collected to assess immune markers and celiac (HLA DQ2, DQ8 and DQ7) genotype. Statistical comparisons used Friedman rank sum tests and paired Wilcoxon signed rank tests.

Result(s)

Twenty-nine IBS patients (27 female, mean age=42, SD=14.4 years) were enrolled in the study; 1 dropped. Similar proportions of patients reacted symptomatically to wheat (11/28, 39.3%), gluten (10/28, 35.7%) and nocebo (8/28, 28.6%). However, there was an overall significant increase in IBS symptoms after wheat (+39.5 on IBS-SSS; p=0.030) but not after gluten (+27.5; p=0.051) or nocebo (+5.5; p=0.236) challenges (Figure 1). Ten participants experienced IBS-SSS symptoms >175 during baseline and did not worsen further during the challenges. TNF-α trended from 1.35 pg/mL after nocebo, 1.47 pg/mL after gluten, to 1.57 pg/mL after wheat; however, this was not significant. Baseline adherence to a GFD was rated excellent in 19 (68%), good in 6 (21%), and fair in 3 (11%) participants. Median GIP levels were 0.584 µg/g after wheat, 0.432 µg/g after gluten, and 0.095 µg/g after nocebo; p<0.0001. Celiac predisposition genes were present in 19/24 participants (10/24 had DQ2, 2/24 had DQ8, and 9/24 had DQ7).

Image

Conclusion(s)

IBS patients self-reporting wheat or gluten sensitivity had worse symptoms after whole wheat, but not purified gluten or nocebo challenge. However, similar proportions of IBS patients reacted to each intervention, suggesting that central mechanisms play an important role in symptom genesis. Furthermore, one third of patients had high symptoms during a GFD and did not react to wheat or gluten challenges, suggesting that other mechanisms are driving their IBS symptoms.

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CIHR, Other

Please indicate your source of funding;

Society for the Study of Celiac Disease (Nestle); Canadian Digestive Health Foundation

Disclosure of Interest

None Declared

A265 TEMPORAL DYNAMICS OF SYMPTOMS AND GUT MICROBIOTA IN EPISODES OF IRRITABLE BOWEL SYNDROME

Background

Irritable bowel syndrome (IBS) is a disorder of gut-brain axis that manifests with chronic abdominal pain, altered bowel habits, and frequent psychiatric comorbidities. Despite mounting evidence showing gut microbiota composition and associated metabolites being altered in IBS, the mechanisms by which they drive the symptoms are unclear. We have previously shown that several IBS symptoms co-occur, that their severity vary among IBS subtypes (10.1093/jcag/gwab049.050), and that several bacterial taxa are differentially modulated during periods of symptom flares and remission. Here we investigate whether the changes in gut microbiome and bacterial metabolites are linked to symptom occurrence and severity.

Purpose

To investigate temporal associations of IBS symptoms with gut microbiota profiles and metabolites.

Method

16S rRNA gene sequencing was performed on stool samples of 28 IBS patients (IBS-D n=20, IBS-C n=8) and 10 healthy controls (HC), collected weekly over a period of 25 weeks, during which gut and mood symptoms were recorded (total of 950 samples). Correlations between principal ordinates obtained from symptom scores and microbiota beta diversity were studied using Procrustes analysis in R. Metabolomics was performed by Mass Spectrometry and analysed using MetaboAnalyst 5.0. Statistical significance was set at p<0.05.

Result(s)

Significant correlation was found between the symptom scores and microbiota beta diversity ordinates over time in 7 patients (5 IBS-D and 2 IBS-C subjects) out of 28 IBS patients. Metabolomics performed on samples selected based on Procrustes analysis and symptom severity scores of individual subjects showed that several pathways are altered in IBS patients (both subtypes) compared to HC, including primary bile acid biosynthesis, beta alanine metabolism, pyrimidine and histidine metabolism. Furthermore, during symptom flares, ornithine, citrulline and gluconic acid vary in IBS-D, while amino acids cysteine, methionine, threonine, and glycine vary in IBS-C subjects.

Conclusion(s)

Our results suggest that IBS symptoms and changes in gut microbiota composition and metabolites must be studied in conjunction, in order to understand the mechanisms underlying IBS pathophysiology. We found that same pathways are altered in IBS subjects irrespective of their subtype, suggestive of a basal metabolic shift in IBS patients. This shift may make them sensitive to further gut microbial modulation of carbohydrate and protein metabolism in IBS-D and IBS-C subjects, respectively, leading to symptom flares. Further analyses are needed to investigate these metabolites and associated bacteria, as they can help identifying subsets of patients with specific disease mechanisms. This will be a steppingstone in moving away from symptom-based subtyping towards mechanism-based grouping and developing effective treatment strategies accordingly.

Disclosure of Interest

None Declared

A53 FECAL BIOACTIVE PHOSPHOLIPIDS AS TRIGGERS OF INTESTINAL HYPERSENSITIVITY IN IRRITABLE BOWEL SYNDROME

Background

Chronic abdominal pain is the most common complaint of patients with gastrointestinal disorders. Its treatment is of limited efficacy as the pathophysiology is poorly understood. The gut microbiome has been shown to affect host physiology, including the neural system function, and growing evidence suggests that it plays an important role in pain perception. Gut microbiota produces a large variety of molecules that can regulate pain perception, such as histamine or bioactive lipids. Phospholipid mediators (PLM) are signaling molecules linked to neurogenic pain as by-products of inflammatory processes in mammals. But it is unknown whether bacteria can produce PLM and whether they play any role in visceral hyperalgesia.

Purpose

To investigate whether PLM are present in stool of patients with chronic abdominal pain, and whether they have potential to induce visceral hypersensitivity.

Method

Stool samples from 27 patients with irritable bowel syndrome (IBS) were collected both during periods of severe and minimal/no pain. The fecal concentration of two PLM (lipid A and lipid B) was determined by ELISA. The passage of lipid A and lipid B through the intestinal barrier was determined ex vivo using Ussing chambers and in vivo by their intracolonic instillation, and their levels assessed in the serosal compartment and the serum, respectively, by ELISA. We used primary cultures of sensory neurons from the dorsal root ganglia (DRG) of conventional mice (SPF) to study the neuronal activation in vitro. Calcium mobilization in DRG sensory neurons was measured by an inverted fluorescence microscope using a fluorescent probe Fluo-4 (1mM) after stimulation with different concentration of lipid A or lipid B. Visceral sensitivity in vivo after intracolonic instillation of combined lipids A and B was evaluated by colorectal distension.

Result(s)

The concentration of lipid A (p=0.001) and lipid B (p=0.002) in stool was significantly higher in IBS patients when experiencing severe abdominal pain compared to periods of minimal pain. The concentration of lipid A (p=0.03; p=0.07) and lipid B (p=0.018; p=0.018) in the serosal compartment and in the serum, respectively, was higher compared to the control condition. The percentage of neurons responding to lipid A or lipid B was significantly higher compared to the control condition, at all tested concentrations. Finally, combined lipid A and lipid B induced visceral hypersensitivity within 10 minutes (p=0.0433) and 90 minutes (p=0.0020) after intracolonic instillation.

Conclusion(s)

Our data suggest that PLM can be found in stool of patients with abdominal pain, that they cross the colonic barrier and increase visceral sensitivity. Further studies are needed to ascertain whether gut bacteria produce these PLM and investigate the precise mechanisms by which PLM induce hyperalgesia.

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CIHR, Other

Please indicate your source of funding;

Weston Family Foundation

Disclosure of Interest

None Declared

Dual Trajectories of Antiretroviral Therapy Adherence and Polypharmacy in Women with HIV in the United States

Background Polypharmacy, using five or more medications, may increase the risk of nonadherence to prescribed treatment. We aimed to identify the interrelationship between trajectories of adherence to antiretroviral therapy (ART) and polypharmacy. Methods We included women with HIV (aged ≥ 18) enrolled in the Women's Interagency HIV Study in the United States from 2014 to 2019. We used group-based trajectory modeling (GBTM) to identify trajectories of adherence to ART and polypharmacy and the dual GBTM to identify the interrelationship between adherence and polypharmacy. Results Overall, 1,538 were eligible (median age of 49 years). GBTM analysis revealed five latent trajectories of adherence with 42% of women grouped in the consistently moderate trajectory. GBTM identified four polypharmacy trajectories with 45% categorized in the consistently low group. Conclusions The joint model did not reveal any interrelationship between ART adherence and polypharmacy trajectories. Future research should consider examining the interrelationship between both variables using objective measures of adherence.

Cohort profile: the ESC EURObservational Research Programme Non-ST-segment elevation myocardial infraction (NSTEMI) Registry

AIMS

The European Society of Cardiology (ESC) EURObservational Research Programme (EORP) Non-ST-segment elevation myocardial infarction (NSTEMI) Registry aims to identify international patterns in NSTEMI management in clinical practice and outcomes against the 2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without ST-segment-elevation.

METHODS AND RESULTS

Consecutively hospitalised adult NSTEMI patients (n = 3620) were enrolled between 11 March 2019 and 6 March 2021, and individual patient data prospectively collected at 287 centres in 59 participating countries during a two-week enrolment period per centre. The registry collected data relating to baseline characteristics, major outcomes (in-hospital death, acute heart failure, cardiogenic shock, bleeding, stroke/transient ischaemic attack, and 30-day mortality) and guideline-recommended NSTEMI care interventions: electrocardiogram pre- or in-hospital, pre-hospitalization receipt of aspirin, echocardiography, coronary angiography, referral to cardiac rehabilitation, smoking cessation advice, dietary advice, and prescription on discharge of aspirin, P2Y12 inhibition, angiotensin converting enzyme inhibitor (ACEi)/angiotensin receptor blocker (ARB), beta-blocker, and statin.

CONCLUSION

The EORP NSTEMI Registry is an international, prospective registry of care and outcomes of patients treated for NSTEMI, which will provide unique insights into the contemporary management of hospitalised NSTEMI patients, compliance with ESC 2015 NSTEMI Guidelines, and identify potential barriers to optimal management of this common clinical presentation associated with significant morbidity and mortality.

325 Candidate Plasma Biomarkers Associated with Residual Feed Intake in Beef Steers

We applied chemical group-based metabolomics to identify blood metabolic signatures associated with residual feed intake in beef cattle. A group of 56 crossbred growing beef steers (average BW = 261 ± 18.5 kg) were adapted to a high-forage total mixed ration in a confinement dry lot equipped with GrowSafe intake nodes for period of 49 d to determine their residual feed intake (RFI) classification. After RFI determination, weekly blood samples were collected three times from beef steers with the least RFI [most efficient (HFE); n = 8; RFI = - 1.93 kg/d] and greatest RFI [least efficient (LFE); n = 8; 2.01 kg/d]. Plasma was prepared by centrifugation and composited for each steer. Metabolome analysis was conducted using a chemical isotope labeling (CIL)/liquid chromatography–mass spectrometry. Analyzed metabolites included those containing amine/phenol-, carboxylic acid-, and carbonyl-chemical groups, which are metabolites associated with metabolism of amino acids, fatty acids, and carbohydrates, respectively. A total number of 495 amine/phenol-containing metabolites were detected and identified; pathway analysis of all these metabolites showed that arginine biosynthesis and histidine metabolism were enriched (P &lt; 0.10) in HFE, relative to LFE steers. Biomarker analysis of the amine/phenol-metabolome identified methionine, 5-aminopentanoic acid, 2-aminohexanedioic acid, and 4-chlorolysine as candidate biomarkers of RFI [false discovery rate ≤ 0.05; Area Under the Curve (AUC) &gt; 0.90]. A total of 118 and 330 metabolites containing carbonyl- and carboxylic acid-chemical groups, respectively, were detected and identified; no metabolic pathways associated with these metabolites were altered and only one candidate biomarker (methionine sulfoxide) was identified. These results identified five candidate metabolite biomarkers of RFI in beef cattle which are mostly associated with amino acid metabolism. Further validation using a larger cohort of beef cattle of different genetic pedigree is required to confirm these findings.

Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.