Genetic Characterization and Influence on Inflammatory Bowel Disease Expression in a Diverse Hispanic South Florida Cohort

Early Life and Childhood Environmental Exposures, More Than Genetic Predisposition, Influence Age of Diagnosis in a Diverse Cohort of 2952 Patients With IBD

BACKGROUND AND AIMS

Inflammatory bowel disease (IBD) develops from a combination of genetic and environmental factors. The aim of this study was to determine the contribution of established environmental risk factors and genetic risk on age of IBD diagnosis in a diverse cohort.

METHODS

IBD patients in clinic completed detailed questionnaires. Blood was drawn for genetic analysis. Environmental risk factors and age of diagnosis were analyzed by ethnicity (Hispanic/Latinx or non-Hispanic White [NHW] individuals) and IBD subtype (ulcerative colitis or Crohn's disease [CD]). Weighted genetic risk scores and environmental risk scores were developed. We examined the relationship between environmental risk scores, genetic risk scores, and age of diagnosis.

RESULTS

A total of 2952 patients were included: 58.9% had CD. A total of 46.83% were of Hispanic background. Early life exposures like cesarean delivery and being born in a developed country were associated with a younger age of IBD diagnosis. Childhood exposures such as frequent plastic water bottle use and having more than 1 bathroom at home were associated with a younger age of IBD. Hispanic and NHW individuals shared similar susceptibilities to environmental exposures. Environmental factors explained 21% of the variance in age of CD diagnosis and 39% in ulcerative colitis. In models incorporating genetic risk score and environmental risk score, the environment was the only significant factor associated with younger age of IBD diagnosis in all groups.

CONCLUSIONS

Early life and childhood exposures impact IBD diagnosis and influence Hispanic and NHW individuals similarly. A cumulative environmental risk score contributes more to age of IBD diagnosis than genetic risk.

Effectiveness and Safety of Biologic Therapy in Hispanic Vs Non-Hispanic Patients With Inflammatory Bowel Diseases: A CA-IBD Cohort Study

BACKGROUND & AIMS

There are limited data on outcomes of biologic therapy in Hispanic patients with inflammatory bowel diseases (IBDs). We compared risk of hospitalization, surgery, and serious infections in Hispanic vs non-Hispanic patients with IBD in a multicenter, electronic health record-based cohort of biologic-treated patients.

METHODS

We identified adult patients with IBD who were new users of biologic agents (tumor necrosis factor α [TNF-α] antagonists, ustekinumab, vedolizumab) from 5 academic institutions in California between 2010 and 2017. We compared the risk of all-cause hospitalization, IBD-related surgery, and serious infections in Hispanic vs non-Hispanic patients using 1:4 propensity score matching and survival analysis.

RESULTS

We compared 240 Hispanic patients (53% male; 45% with ulcerative colitis; 73% TNF-α antagonist-treated; 20% with prior biologic exposure) with 960 non-Hispanic patients (51% male; 44% with ulcerative colitis; 67% TNF-α antagonist-treated; 27% with prior biologic exposure). After propensity score matching, Hispanic patients were younger (37 ± 15 vs 40 ± 16 y; P = .02) and had a higher burden of comorbidities (Elixhauser index, >0; 37% vs 26%; P < .01), without any differences in patterns of medication use, burden of inflammation, and hospitalizations. Within 1 year of biologic initiation, Hispanic patients had higher rates of hospitalizations (31% vs 23%; adjusted hazard ratio [aHR], 1.32; 95% CI, 1.01-1.74) and IBD-related surgery (7.1% vs 4.6%; aHR, 2.00; 95% CI, 1.07-3.72), with a trend toward higher risk of serious infections (8.8% vs 4.9%; aHR, 1.74; 95% CI, 0.99-3.05).

CONCLUSIONS

In a multicenter, propensity score-matched cohort of biologic-treated patients with IBD, Hispanic patients experienced higher rates of hospitalization, surgery, and serious infections. Future studies are needed to investigate the biological, social, and environmental drivers of these differences.

Social Determinants of Health Mediate COVID-19 Disparities in South Florida

BACKGROUND

There are several reports of health disparities related to COVID-19. Understanding social determinants of health (SDoH) could help develop mitigation strategies to prevent further COVID-19 spread. Our aim is to evaluate self-reported and census-based SDoH as a mediator of health disparities in COVID-19.

METHODS

We conducted a cross-sectional ecological study and included all COVID-19 cases report by the COVID-19 Florida dashboard as the dependent variable. The independent variables were census-based median household income, population and household size, and self-reported SDoH using a validated survey. We calculated the incidence rate ratio (IRR) of COVID-19 by zip code using Poisson regression and structured equation modelling to evaluate the mediation effect of income and SDoH on COVID-19 cases.

RESULTS

We included 97,594 COVID-19 positive cases across 79 Miami-Dade ZIP codes with a median age of 43 years; females represented 50.7% of the cases. The highest IRR (4.44) were for ZIP code 33125 (income $21,106, 6% Black, 93% Hispanic), while the lowest IRR (0.86) was for ZIP code 33146 (median household incomes $96,609, 3% Black and 53% Hispanic). In structured equation models, the indirect coefficient of income in the relationship between race/ethnicity and COVID-19 were only significant for Blacks and not Hispanics.

CONCLUSIONS

This ecological analysis using ZIP code and aggregate individual-level SDoH shows that in Miami-Dade county, COVID infection is associated with economic disadvantage in a particular geographical area and not with racial/ethnic distribution.

Effects of Race and Ethnicity on Diagnosis and Management of Inflammatory Bowel Diseases

Although Crohn's disease (CD) and ulcerative colitis (UC) have been considered as disorders that affect individuals of European ancestry, the epidemiology of the inflammatory bowel diseases (IBDs) is changing. Coupled with the increasing incidence of IBD in previously low-incidence areas, the population demographics of IBD in the United States are also changing, with increases among non-White races and ethnicities. It is therefore important to fully understand the epidemiology and progression of IBD in different racial and ethnic groups, and the effects of race and ethnicity on access to care, use of resources, and disease-related outcomes. We review differences in IBD development and progression among patients of different races and ethnicities, discussing the effects of factors such as access to care, delays in diagnosis, and health and disease perception on disparities in IBD care and outcomes. We identify research priorities for improving health equity among minority patients with IBD.

Epigenome-metabolome-microbiome axis in health and IBD

Environmental triggers in the context of genetic susceptibility drive phenotypes of complex immune disorders such as Inflammatory bowel disease (IBD). One such trigger of IBD is perturbations in enteric commensal bacteria, fungi or viruses that shape both immune and neuronal state. The epigenome acts as an interface between microbiota and context-specific gene expression and is thus emerging as a third key contributor to IBD. Here we review evidence that the host epigenome plays a significant role in orchestrating the bidirectional crosstalk between mammals and their commensal microorganisms. We discuss disruption of chromatin regulatory regions and epigenetic enzyme mutants as a causative factor in IBD patients and mouse models of intestinal inflammation and consider the possible translation of this knowledge. Furthermore, we present emerging insights into the intricate connection between the microbiome and epigenetic enzyme activity via host or bacterial metabolites and how these interactions fine-tune the microorganism-host relationship.

Mucosal Microbiome Profiles Polygenic Irritable Bowel Syndrome in Mestizo Individuals

Irritable bowel syndrome (IBS) is the most frequent functional gastrointestinal disorder, worldwide, with a high prevalence among Mestizo Latin Americans. Because several inflammatory disorders appear to affect this population, a further understanding of host genomic background variants, in conjunction with colonic mucosa dysbiosis, is necessary to determine IBS physiopathology and the effects of environmental pressures. Using a simple polygenic model, host single nucleotide polymorphisms (SNPs) and the taxonomic compositions of microbiota were compared between IBS patients and healthy subjects. As proof of concept, five IBS-Rome III patients and five healthy controls (HCs) were systematically studied. The human and bacterial intestinal metagenome of each subject was taxonomically annotated and screened for previously annotated IBS, ulcerative colitis, and Crohn's disease-associated SNPs or taxon abundance. Dietary data and fecal markers were collected and associated with the intestinal microbiome. However, more than 1,000 variants were found, and at least 76 SNPs differentiated IBS patients from HCs, as did associations with 4 phyla and 10 bacterial genera. In this study, we found elements supporting a polygenic background, with frequent variants, among the Mestizo population, and the colonic mucosal enrichment of Bacteroides, Alteromonas, Neisseria, Streptococcus, and Microbacterium, may serve as a hallmark for IBS.

Identification of functional missense single-nucleotide polymorphisms in TNFAIP3 in a predominantly Hispanic population

Background:

Tumor necrosis factor alpha-induced protein 3 (TNFAIP3) is a multifunctional ubiquitin binding and editing enzyme that regulates inflammation. Genetic studies have implicated polymorphisms within the TNFAIP3 locus to the development of numerous immune-related diseases. This study evaluated the frequencies of single-nucleotide polymorphism (SNPs) within the exonic regions of the TNFAIP3 gene and an associated point mutation from the Illumina array among a predominantly Hispanic cohort.

Methods:

Genomic DNA was obtained from 721 participants and sequencing of all TNFAIP3 exons and an intergenic point mutation (rs6920220) was performed. In-vitro functional assessment was performed by transfecting mutated TNFAIP3 constructs into TNFAIP3 knockout cells containing the NF-kB luciferase reporter and stimulating with TNFα. Comparative statistics were performed with Student’s t-test for continuous variables and chi-squared test for categorical variables.

Results:

Sequencing revealed two missense SNPs, rs146534657:A>G and rs2230926:T>G, both within exon 3 of TNFAIP3, which encodes the protein’s deubiquitinating enzymatic domain. Frequencies of all three point mutations differed significantly across racial groups (χ²-test, P = 0.014 to P < 0.001). Compared to Caucasians, rs146534657:A>G was overrepresented among Hispanics (odds ratio (OR) [95% CI] 4.05 [1.24−13.18]), and rs2230926:T>G was more prevalent among African-Americans (OR [95% CI] 3.65 [1.58−8.43]). In-vitro assays confirm rs146534657:A>G and rs2230926:T>G decrease the ability of TNFAIP3 to abrogate NF-κB activation by 2-fold (P < 0.01) and 1.7-fold (P < 0.01), respectively.

Conclusions:

This study reports the frequency of rs146534657:A>G among Hispanics and is the first to evaluate its potential physiologic impact, establishing a basis for future research as a potential biomarker among this population.

Exposure of the Host-Associated Microbiome to Nutrient-Rich Conditions May Lead to Dysbiosis and Disease Development-an Evolutionary Perspective

Inflammatory diseases, such as inflammatory bowel diseases, are dramatically increasing worldwide, but an understanding of the underlying factors is lacking. We here present an ecoevolutionary perspective on the emergence of inflammatory diseases.

Inflammatory diseases, such as inflammatory bowel diseases, are dramatically increasing worldwide, but an understanding of the underlying factors is lacking. We here present an ecoevolutionary perspective on the emergence of inflammatory diseases. We propose that adaptation has led to fine-tuned host-microbe interactions, which are maintained by secreted host metabolites nourishing the associated microbes. A constant elevation of nutrients in the gut environment leads to an increased activity and changed functionality of the microbiota, thus severely disturbing host-microbe interactions and leading to dysbiosis and disease development. In the past, starvation and pathogen infections, causing diarrhea, were common incidences that reset the gut bacterial community to its “human-specific-baseline.” However, these natural clearing mechanisms have been virtually eradicated in developed countries, allowing a constant uncontrolled growth of bacteria. This leads to an increase of bacterial products that stimulate the immune system and ultimately might initiate inflammatory reactions.

Hispanics Coming to the US Adopt US Cultural Behaviors and Eat Less Healthy: Implications for Development of Inflammatory Bowel Disease

INTRODUCTION

The incidence of inflammatory bowel disease (IBD) among US Hispanics is rising. Adoption of an American diet and/or US acculturation may help explain this rise.

AIMS

To measure changes in diet occurring with immigration to the USA in IBD patients and controls, and to compare US acculturation between Hispanics with versus without IBD. Last, we examine the current diet of Hispanics with IBD compared to the diet of Hispanic controls.

METHODS

This was a cross-sectional study of Hispanic immigrants with and without IBD. Participants were recruited from a university-based GI clinic. All participants completed an abbreviated version of the Stephenson Multi-Group Acculturation Scale and a 24-h diet recall (the ASA-24). Diet quality was calculated using the Healthy Eating Index (HEI-2010).

RESULTS

We included 58 participants: 29 controls and 29 IBD patients. Most participants were Cuban or Colombian. Most participants, particularly those with IBD, reported changing their diet after immigration (72% of IBD and 57% of controls). IBD participants and controls scored similarly on US and Hispanic acculturation measures. IBD patients and controls scored equally poorly on the HEI-2010, although they differed on specific measures of poor intake. IBD patients reported a higher intake of refined grains and lower consumption of fruits, whereas controls reported higher intake of empty calories (derived from fat and alcohol).

CONCLUSION

The majority of Hispanics change their diet upon immigration to the USA and eat poorly irrespective of the presence of IBD. Future studies should examine gene-diet interactions to better understand underlying causes of IBD in Hispanics.