Crohn's Disease-Associated Pathogenic Mutation in the Manganese Transporter ZIP8 Shifts the Ileal and Rectal Mucosal Microbiota Implicating Aberrant Bile Acid Metabolism

BACKGROUND

A pathogenic mutation in the manganese transporter ZIP8 (A391T; rs13107325) increases the risk of Crohn's disease. ZIP8 regulates manganese homeostasis and given the shared need for metals between the host and resident microbes, there has been significant interest in alterations of the microbiome in carriers of ZIP8 A391T. Prior studies have not examined the ileal microbiome despite associations between ileal disease and ZIP8 A391T.

METHODS

Here, we used the Pediatric Risk Stratification Study (RISK)  cohort to perform a secondary analysis of 16S ribosomal RNA gene sequencing data obtained from ileal and rectal mucosa to study associations between ZIP8 A391T carrier status and microbiota composition.

RESULTS

We found sequence variants mapping to Veillonella were decreased in the ileal mucosa of ZIP8 A391T carriers. Prior human studies have demonstrated the sensitivity of Veillonella to bile acid abundance. We therefore hypothesized that bile acid homeostasis is differentially regulated in carriers of ZIP8 A391T. Using a mouse model of ZIP8 A391T, we demonstrate an increase in total bile acids in the liver and stool and decreased fibroblast growth factor 15 (Fgf15) signaling, consistent with our hypothesis. We confirmed dysregulation of FGF19 in the 1000IBD cohort, finding that plasma FGF19 levels are lower in ZIP8 A391T carriers with ileocolonic Crohn's disease.

CONCLUSIONS

In the search for genotype-specific therapeutic paradigms for patients with Crohn's disease, these data suggest targeting the FGF19 pathway in ZIP8 A391T carriers. Aberrant bile acid metabolism may precede development of Crohn's disease and prioritize study of the interactions between manganese homeostasis, bile acid metabolism and signaling, and complicated ileal Crohn's disease.

Evaluating the implementation of a dynamic digital application to enable community-based decentralisation of rheumatic heart disease case management in Uganda: protocol for a hybrid type III effectiveness-implementation study

INTRODUCTION

Rheumatic heart disease (RHD) affects over 39 million people worldwide, the majority in low-income and middle-income countries. Secondary antibiotic prophylaxis (SAP), given every 3-4 weeks can improve outcomes, provided more than 80% of doses are received. Poor adherence is strongly correlated with the distance travelled to receive prophylaxis. Decentralising RHD care has the potential to bridge these gaps and at least maintain or potentially increase RHD prophylaxis uptake. A package of implementation strategies was developed with the aim of reducing barriers to optimum SAP uptake.

METHODS AND ANALYSIS

A hybrid implementation-effectiveness study type III was designed to evaluate the effectiveness of a package of implementation strategies including a digital, cloud-based application to support decentralised RHD care, integrated into the public healthcare system in Uganda. Our overarching hypothesis is that secondary prophylaxis adherence can be maintained or improved via a decentralisation strategy, compared with the centralised delivery strategy, by increasing retention in care. To evaluate this, eligible patients with RHD irrespective of their age enrolled at Lira and Gulu hospital registry sites will be consented for decentralised care at their nearest participating health centre. We estimated a sample size of 150-200 registrants. The primary outcome will be adherence to secondary prophylaxis while detailed implementation measures will be collected to understand barriers and facilitators to decentralisation, digital application tool adoption and ultimately its use and scale-up in the public healthcare system.

ETHICS AND DISSEMINATION

This study was approved by the Institutional Review Board (IRB) at Cincinnati Children's Hospital Medical Center (IRB 2021-0160) and Makerere University School of Medicine Research Ethics Committee (Mak-SOMREC-2021-61). Participation will be voluntary and informed consent or assent (>8 but <18) will be obtained prior to participation. At completion, study findings will be communicated to the public, key stakeholders and submitted for publication.

Worldwide Exploration of Renal Replacement Outcomes Collaborative in Kidney Disease (WE-ROCK)

Introduction

Continuous renal replacement therapy (CRRT) is used for the symptomatic management of acute kidney injury (AKI) and fluid overload (FO). Contemporary reports on pediatric CRRT are small and single center in design. Large international studies evaluating CRRT practice and outcomes are lacking. Herein, we describe the design of a multinational collaborative.

Methods

The Worldwide Exploration of Renal Replacement Outcomes Collaborative in Kidney Disease (WE-ROCK) is an international collaborative of pediatric specialists whose mission is to improve short- and long-term outcomes of children treated with CRRT. The aims of this multicenter retrospective study are to describe the epidemiology, liberation patterns, association of fluid balance and timing of CRRT initiation, and CRRT prescription with outcomes.

Results

We included children (n = 996, 0-25 years) admitted to an intensive care unit (ICU) and treated with CRRT for AKI or FO at 32 centers (in 7 countries) from 2018 to 2021. Demographics and clinical characteristics before CRRT initiation, during the first 7 days of both CRRT, and liberation were collected. Outcomes include the following: (i) major adverse kidney events at 90 days (mortality, dialysis dependence, and persistent kidney dysfunction), and (ii) functional outcomes (functional stats scale).

Conclusion

The retrospective WE-ROCK study represents the largest international registry of children receiving CRRT for AKI or FO. It will serve as a broad and invaluable resource for the field of pediatric critical care nephrology that will improve our understanding of practice heterogeneity and the association of CRRT with clinical and patient-centered outcomes. This will generate preliminary data for future interventional trials in this area.

Early triage echocardiography to predict outcomes in patients admitted with COVID-19: a multicenter study

INTRODUCTION

Cardiac involvement seems to impact prognosis of COVID-19, especially in critically ill patients. We aimed to assess the prognostic value of right ventricular (RV) and left ventricular (LV) dysfunction, evaluated by bedside triage echocardiography (echo), in patients admitted to emergency departments (ED) in the US with COVID-19. We also assessed the feasibility of using cloud imaging for sharing and interpreting echocardiograms.

METHODS

Patients admitted to three reference EDs with confirmed COVID-19 underwent triage echo within 72 h of symptom onset with remote interpretation. Clinical and laboratory data, as well as COVID-19 symptoms, were collected. The association between echo variables, demographics and clinical data with all-cause hospital mortality and intensive care unit (ICU) admission was assessed using logistic regression.

RESULTS

Three hundred ninety-nine patients were enrolled, 41% women, with a mean age of 62±16 years. Mean oxygen saturation on presentation was 92.3± 9.2%. Compared to in-hospital survivors, non-survivors were older, had lower oxygen saturation on presentation, were more likely to have a chronic condition and had lower LV ejection fraction (50.3±19.7% vs. 58.0±13.6%) (P < .05). In the cohort, 101 (25%) patients had moderate/severe LV dysfunction, 131 (33%) had moderate/severe RV dysfunction. Advanced age and lower oxygen saturation were independently associated with death and ICU admission. LV and RV function, or other echo variables, were not independent predictors of outcomes.

CONCLUSION

In patients admitted with COVID-19 undergoing early echo triage, the independent predictors of death and ICU admission were age and oxygen saturation. The inclusion of echo variables did not improve prediction of unfavorable outcomes.

Metagenomic analysis of the fecal microbiome in patients with colorectal cancer compared to healthy controls as a function of age

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Background: Colorectal cancer (CRC) incidence is increasing in young patients ( < 50 years old) without a clear etiology. Emerging data has implicated the fecal microbiome in CRC carcinogenesis. However, its impact on young onset CRC (YO-CRC) is poorly defined. Colibactin producing E. Coli and fadA producing Fusobacterium nucleatum can drive CRC carcinogenesis, however their effects across the age spectrum are unknown. Methods: We performed a meta-analysis of fecal metagenomics sequencing from n = 692 patients with CRC and n = 602 healthy controls from eleven studies to evaluate species and known microbial derived factors (colibactin and FadA) associated with CRC as a function of age. Generalized linear mixed effects regression was used to model the predicted prevalence of gene families and taxa as a non-linear function of age. Two-stage individual patient data meta-analysis (IPDMA) with adjustment for gender, CRC status, and body mass index was also used to estimate summary odds ratios for colibactin, F. nucleatum, and E. Coli. Interaction ORs were obtained to assess the difference in the effect of each gene or taxa on CRC case status in YO-CRC. Shannon Diversity index and metabolic pathway differences in the fecal metagenome for YO-CRC patients were assessed using phyloseq and MetaCyc respectively using an IPDMA approach. Results: Summary odds ratios (OR) for CRC were increased relative to controls with the presence of colibactin (OR 1.92 95%CI 1.08-3.38), fadA (OR 4.57 95%CI 1.63-12.85), and F. nucleatum (OR 6.93 95%CI 3.01-15.96) in models of all patients adjusted for age, gender, and body mass index. The OR for CRC for the presence of E.coli was 2.02 (0.92-4.45). An increase in the prevalence of F. nucleatum (OR = 1.40 [1.18; 1.65] and Escherichia coli (OR = 1.14 [1.02; 1.28]) per 10-year increase in age was observed in models including samples from both CRC and healthy controls. No difference was observed for Shannon Diversity (OR 1.36 95%CI 0.68-2.72) or MetaCyc pathways in YO-CRC patients. Species relative abundance was differentially enriched in YO-CRC relative to old CRC patients and controls for five species- Intestinimonas butyriciproducens, Holdemania filiformis, Firimicutues bacterium CAG 83, Bilophilia wadsworthia, and Alistipes putredinis. Conclusions: Strong associations with CRC status were observed for colibactin, fadA, and F. nucleatum with increased F. nucleatum in older patients. Several species were enriched in YO-CRC patients including B. wadsworthia which can produce carcinogenic sulfur metabolites and is increased with adherence to a sulfur microbial diet-low in vegetables and legumes. A sulfur microbial diet has also been associated with higher incidence of YO-CRC in population studies (Nguyen Gastroenterology 2021). Additional study is warranted to understand causal mechanisms of enriched species observed in YO-CRC patients.

Clinical outcomes of children with rheumatic heart disease

OBJECTIVE

To evaluate the long-term clinical outcomes of children with rheumatic heart disease (RHD) in Uganda, and determine characteristics that predict adverse outcomes.

METHODS

This retrospective cohort study evaluated the risk of death in Ugandan children with clinical RHD from 2010 to 2018; enrolling children aged 5-18 years old from an existing registry. Demographic data and clinical data (baseline complications, RHD severity, cardiac interventions) were collected. The primary outcome was survival. Univariable and multivariable hazard ratios (HR) were obtained from Cox proportional hazards regression. Survival probabilities were developed using Kaplan-Meier curves; log-rank tests compared survival based on cardiac interventions, disease severity and time of enrolment.

RESULTS

612 cases met inclusion criteria; median age 12.8 years (IQR 5.3), 37% were male. Thirty-one per cent (187 of 612) died during the study period; median time to death 7.8 months (IQR 18.3). In univariable analysis, older age (HR 1.26, 95% CI=1.0 to 1.58), presence of baseline complications (HR 2.06, 95% CI=1.53 to 2.78) and severe RHD (HR 5.21, 95% CI=2.15 to 12.65) were associated with mortality. Cardiac intervention was associated with a lower risk of mortality (HR 0.06, 95% CI=0.02 to 0.24). In multivariable models, baseline complications (HR 1.78, 95% CI=1.31 to 2.41), severe RHD (HR 4.58, 95% CI=1.87 to 11.23) and having an intervention (HR 0.05, 95% CI=0.01 to 0.21) remained statistically significant. Kaplan-Meier survival curves demonstrated >25% mortality in the first 30 months, with significant differences in mortality based on intervention status and severity of disease.

CONCLUSIONS

The mortality rate of children with clinical RHD in Uganda exceeds 30%, over an 8-year time frame, despite in-country access to cardiac interventions. Children at highest risk were those with cardiac complications at baseline and severe RHD.

Modelling study of the ability to diagnose acute rheumatic fever at different levels of the Ugandan healthcare system

OBJECTIVE

To determine the ability to accurately diagnose acute rheumatic fever (ARF) given the resources available at three levels of the Ugandan healthcare system.

METHODS

Using data obtained from a large epidemiological database on ARF conducted in three districts of Uganda, we selected variables that might positively or negatively predict rheumatic fever based on diagnostic capacity at three levels/tiers of the Ugandan healthcare system. Variables were put into three statistical models that were built sequentially. Multiple logistic regression was used to estimate ORs and 95% CI of predictors of ARF. Performance of the models was determined using Akaike information criterion, adjusted R2, concordance C statistic, Brier score and adequacy index.

RESULTS

A model with clinical predictor variables available at a lower-level health centre (tier 1) predicted ARF with an optimism corrected area under the curve (AUC) (c-statistic) of 0.69. Adding tests available at the district level (tier 2, ECG, complete blood count and malaria testing) increased the AUC to 0.76. A model that additionally included diagnostic tests available at the national referral hospital (tier 3, echocardiography, anti-streptolysin O titres, erythrocyte sedimentation rate/C-reactive protein) had the best performance with an AUC of 0.91.

CONCLUSIONS

Reducing the burden of rheumatic heart disease in low and middle-income countries requires overcoming challenges of ARF diagnosis. Ensuring that possible cases can be evaluated using electrocardiography and relatively simple blood tests will improve diagnostic accuracy somewhat, but access to echocardiography and tests to confirm recent streptococcal infection will have the greatest impact.

Bleeding and thrombotic risk in pregnant women with Fontan physiology

BACKGROUND/OBJECTIVES

Pregnancy may potentiate the inherent hypercoagulability of the Fontan circulation, thereby amplifying adverse events. This study sought to evaluate thrombosis and bleeding risk in pregnant women with a Fontan.

METHODS

We performed a retrospective observational cohort study across 13 international centres and recorded data on thrombotic and bleeding events, antithrombotic therapies and pre-pregnancy thrombotic risk factors.

RESULTS

We analysed 84 women with Fontan physiology undergoing 108 pregnancies, average gestation 33±5 weeks. The most common antithrombotic therapy in pregnancy was aspirin (ASA, 47 pregnancies (43.5%)). Heparin (unfractionated (UFH) or low molecular weight (LMWH)) was prescribed in 32 pregnancies (30%) and vitamin K antagonist (VKA) in 10 pregnancies (9%). Three pregnancies were complicated by thrombotic events (2.8%). Thirty-eight pregnancies (35%) were complicated by bleeding, of which 5 (13%) were severe. Most bleeds were obstetric, occurring antepartum (45%) and postpartum (42%). The use of therapeutic heparin (OR 15.6, 95% CI 1.88 to 129, p=0.006), VKA (OR 11.7, 95% CI 1.06 to 130, p=0.032) or any combination of anticoagulation medication (OR 13.0, 95% CI 1.13 to 150, p=0.032) were significantly associated with bleeding events, while ASA (OR 5.41, 95% CI 0.73 to 40.4, p=0.067) and prophylactic heparin were not (OR 4.68, 95% CI 0.488 to 44.9, p=0.096).

CONCLUSIONS

Current antithrombotic strategies appear effective at attenuating thrombotic risk in pregnant women with a Fontan. However, this comes with high (>30%) bleeding risk, of which 13% are life threatening. Achieving haemostatic balance is challenging in pregnant women with a Fontan, necessitating individualised risk-adjusted counselling and therapeutic approaches that are monitored during the course of pregnancy.

Rheumatic Heart Disease in the United States: Forgotten But Not Gone: Results of a 10 Year Multicenter Review

Background

Recent evaluation of rheumatic heart disease (RHD) mortality demonstrates disproportionate disease burden within the United States. However, there are few contemporary data on US children living with acute rheumatic fever (ARF) and RHD.

Methods and Results

Twenty‐two US pediatric institutions participated in a 10‐year review (2008–2018) of electronic medical records and echocardiographic databases of children 4 to 17 years diagnosed with ARF/RHD to determine demographics, diagnosis, and management. Geocoding was used to determine a census tract‐based socioeconomic deprivation index. Descriptive statistics of patient characteristics and regression analysis of RHD classification, disease severity, and initial antibiotic prescription according to community deprivation were obtained. Data for 947 cases showed median age at diagnosis of 9 years; 51% and 56% identified as male and non‐White, respectively. Most (89%) had health insurance and were first diagnosed in the United States (82%). Only 13% reported travel to an endemic region before diagnosis. Although 96% of patients were prescribed secondary prophylaxis, only 58% were prescribed intramuscular benzathine penicillin G. Higher deprivation was associated with increasing disease severity (odds ratio, 1.25; 95% CI, 1.08–1.46).

Conclusions

The majority of recent US cases of ARF and RHD are endemic rather than the result of foreign exposure. Children who live in more deprived communities are at risk for more severe disease. This study demonstrates a need to improve guideline‐based treatment for ARF/RHD with respect to secondary prophylaxis and to increase research efforts to better understand ARF and RHD in the United States.

Peripheral venous pressure changes during exercise are associated with adverse Fontan outcomes

OBJECTIVE

Elevated central venous pressure (CVP) plays an important role in the development of adverse Fontan outcomes. Peripheral venous pressure (PVP) has been validated as a surrogate for CVP in Fontan patients. We hypothesised that PVP in response to exercise will be associated with a greater prevalence of Fontan morbidity.

METHODS

Adult Fontan patients had cardiopulmonary exercise testing (CPET) with PVP monitoring in the upper extremity between 2015 and 2018. PVP at rest, during unloaded cycling and at peak exercise was compared between those with and without adverse Fontan outcomes including arrhythmia, unscheduled hospital admissions, heart failure requiring diuretics, need for reintervention and a composite outcome of the above morbidities, heart transplantation and death.

RESULTS

Forty-six patients with a mean age at CPET of 26.9±9.5 years. During exercise, PVP increased from 13.6±3.5 mm Hg at rest, to 16.5±3.9 mm Hg during unloaded cycling, to 23.0±5.5 mm Hg at peak exercise. Unloaded and peak PVP were more strongly associated than resting PVP with all adverse outcomes, except reintervention (composite outcome: resting PVP: OR 2.8, p=0.023; unloaded PVP: OR 6.1, p=0.001; peak PVP: OR 4.0, p<0.001). Cut-offs determined using ROC curve analysis had high specificity for the composite outcome (88% unloaded PVP ≥18 mm Hg; 89% peak PVP ≥25 mm Hg).

CONCLUSION

Higher PVP at unloaded and peak exercise was strongly associated with a higher prevalence of adverse Fontan outcomes. Minimally invasive PVP monitoring during CPET may serve as a useful tool for risk stratifying individuals with a Fontan.

Gut Microbiome Differences in Infants at High vs. Low Risk of Early Obesity

Objectives

Fifty % of infants above the BMI 85th percentile will develop overweight or obesity by age 6. This study aimed to evaluate differences in the gut microbial ecology of infants at high- and low-risk of developing overweight or obesity.

Methods

Infants enrolled at age 6 months were classified into high-risk or low-risk based on BMI ≥85th or &lt;85th percentile; stool samples were collected from the diaper and microbial DNA extracted. Metagenomic shotgun sequencing was performed on the Illumina HiSeq at an average depth of 15 million paired-end reads per sample. Taxonomic profiling was performed using Kraken against a custom genome database. Multiple linear regression was used to test for group differences in observed species richness and Shannon diversity, adjusted for age, delivery type, breast feeding, and introduction of solid food. Beta-diversity ordinations assessed group clustering according to species community composition. Moderated negative binomial regression using DESeq2 was used to identify differentially abundant species. Functional profiling of microbial pathways was conducted using HUMAnN2, and group differences assessed using ALDEx2.

Results

Sixty-one infants (46% male, 69% black) were enrolled; 13 (21%) were high-risk. Low-risk and high-risk infants differed by race (mixed race more common in high-risk, P = 0.02), and marginally by parent marital status and number of older children in the household (both P = 0.06). Number of observed species were marginally higher in the high-risk group (P = 0.09), with no group differences in beta-diversity ordinations. Several Streptococcus, Enterobacter, Bacteroides and Lactobacillus species were more abundant in high-risk infants, while Haemophilus, Bifidobacterium and Prevotella species were more abundant in low-risk infants. High-risk infants had a more “mature” microbiome characterized by increased abundance of Ruminococcus, Blautia, and Lachnospiraceae. The PWY.5676 Acetyl-CoA fermentation to butyrate pathway was also significantly enriched in high-risk infants.

Conclusions

Infants at high risk for obesity are characterized by a microbiome more abundant in species seen in older children, and with a greater functional capacity to harvest energy from complex carbohydrates.

Funding Sources

Digestive Health Center Pilot Grant.

Does Exposure to Type 1 Diabetes In Utero Increase the Risk of Metabolic Syndrome, Especially Abdominal Obesity, in Young Adults?

Objectives

Metabolic syndrome (MetS) is a clustering of metabolic abnormalities including abdominal obesity that can lead to cardiovascular disease, diabetes, and stroke. Exposure to maternal diabetes in utero increases MetS risk in offspring. Consuming a healthy diet may reduce the risk. The MetS severity z-score (MetS-z) is a sex- and race-specific score developed by Gurka et al. to indicate MetS risk or severity on a continuous scale. We sought to examine if offspring of mothers with Type 1 Diabetes (T1D) have greater risk or severity of MetS, particularly with respect to abdominal obesity, compared to subjects from the National Health and Nutrition Examination Survey (NHANES).

Methods

The Transgenerational Effects of Adult Morbidity (TEAM) study is a prospective cohort study investigating the impact of gestational exposure to maternal T1D on metabolic health of offspring. To date, 100 young adult (24–42 y) offspring of mothers with T1D have been enrolled. TEAM participants were compared to a population sample of ∼1:2 age-, sex- and race-matched controls from NHANES 2015–2016. Abdominal obesity was assessed by sagittal abdominal diameter (SAD), an indicator of abdominal visceral fat. Usual diet was estimated by averaging intake from multiple 24-hour diet recall interviews. MetS-z was calculated with equations specific for sex, age, and race, and diet quality was assessed by the Healthy Eating Index (HEI)-2015 score. Descriptive and regression analyses were employed to compare TEAM and NHANES participants on MetS-z and SAD. HEI score was examined as a covariate and a potential moderator.

Results

SAD was higher in TEAM than NHANES participants (23.4 vs 21.8 cm, P = 0.005). No material differences in MetS-z (–0.02 vs −0.17, P = 0.18) or HEI score (51.3 vs 48.9, P = 0.26) were observed. SAD and MetS-z were highly correlated (r = 0.72, P &lt; 0.001). HEI score exhibited a weak inverse correlation with both SAD and MetS-z (r = −0.19 and r = −0.17). HEI was not found to modify the association between cohort membership and MetS-z or SAD.

Conclusions

We observed higher SAD in offspring of mothers with T1D compared to NHANES participants and this effect persisted after controlling for HEI. SAD is associated with increased risk for MetS, yet no material difference in MetS z-score was observed between the groups.

Funding Sources

NIH, NIDDK R01DK109956; 5UL1TR001425–04.

Anatomical predictors of conduction damage after transcatheter implantation of the aortic valve

Objective

Conduction damage following transcatheter aortic valve implantation (TAVI) remains common. Anatomical risk factors remain elusive. We assessed the impact of variability in the dimensions of the membranous septum and position of the aortic root on the occurrence of conduction damage following TAVI.

Methods

The dimensions of the membranous septum, the rotational position of the aortic root correlating to variability in the central fibrous body width, and wedging of the aortic root were assessed on pre-TAVI CT datasets. The depth of implantation was measured from the final aortic angiogram. The variables were compared with the occurrence of both permanent pacemaker insertion (PPI) and left bundle branch block (LBBB) following TAVI.

Results

Of 200 patients who met inclusion criteria (mean age = 81 years ± 7.7, 49% men), 20.5 % underwent PPI after TAVI. New LBBB occurred in 23.5%, 21.3 % of whom required PPI. Preprocedural right bundle branch block (OR = 7.00; CI 3.13 to 15.64), valve type (OR=2.35; CI 1.13 to 4.87), depth of implantation (OR=1.62; CI 1.01 to 2.61) and the difference between depth of implantation and the distance from the virtual basal ring to the inferior margin of the membranous septum (OR=0.61; CI 0.38 to 0.99) were all associated with PPI, with similar associations with LBBB. No gross anatomical variable alone was associated with conduction damage.

Conclusions

Gross anatomical variation of the aortic root and its underlying support, including the membranous septum, were not associated with the occurrence of either PPI or new LBBB. Procedural characteristics associated with these adverse outcomes suggest that the depth of implantation and radial force of the bioprosthesis, regardless of gross anatomical variability, increase the risk for conduction damage.