Browsing by Author "Oliva-Hemker, Maria"

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    Association of Baseline Luminal Narrowing With Ileal Microbial Shifts and Gene Expression Programs and Subsequent Transmural Healing in Pediatric Crohn Disease
    (Oxford University Press, 2021) Ta, Allison D.; Ollberding, Nicholas J.; Karns, Rebekah; Haberman, Yael; Alazraki, Adina L.; Hercules, David; Baldassano, Robert; Markowitz, James; Heyman, Melvin B.; Kim, Sandra; Kirschner, Barbara; Shapiro, Jason M.; Noe, Joshua; Oliva-Hemker, Maria; Otley, Anthony; Pfefferkorn, Marian; Kellermayer, Richard; Snapper, Scott; Rabizadeh, Shervin; Xavier, Ramnik; Dubinsky, Marla; Hyams, Jeffrey; Kugathasan, Subra; Jegga, Anil G.; Dillman, Jonathan R.; Denson, Lee A.; Pediatrics, School of Medicine
    Background: Transmural healing (TH) is associated with better long-term outcomes in Crohn disease (CD), whereas pretreatment ileal gene signatures encoding myeloid inflammatory responses and extracellular matrix production are associated with stricturing. We aimed to develop a predictive model for ileal TH and to identify ileal genes and microbes associated with baseline luminal narrowing (LN), a precursor to strictures. Materials and methods: Baseline small bowel imaging obtained in the RISK pediatric CD cohort study was graded for LN. Ileal gene expression was determined by RNASeq, and the ileal microbial community composition was characterized using 16S rRNA amplicon sequencing. Clinical, demographic, radiologic, and genomic variables were tested for association with baseline LN and future TH. Results: After controlling for ileal location, baseline ileal LN (odds ratio [OR], 0.3; 95% confidence interval [CI], 0.1-0.8), increasing serum albumin (OR, 4; 95% CI, 1.3-12.3), and anti-Saccharomyces cerevisiae antibodies IgG serology (OR, 0.97; 95% CI, 0.95-1) were associated with subsequent TH. A multivariable regression model including these factors had excellent discriminant power for TH (area under the curve, 0.86; positive predictive value, 80%; negative predictive value, 87%). Patients with baseline LN exhibited increased Enterobacteriaceae and inflammatory and extracellular matrix gene signatures, coupled with reduced levels of butyrate-producing commensals and a respiratory electron transport gene signature. Taxa including Lachnospiraceae and the genus Roseburia were associated with increased respiratory and decreased inflammatory gene signatures, and Aggregatibacter and Blautia bacteria were associated with reduced extracellular matrix gene expression. Conclusions: Pediatric patients with CD with LN at diagnosis are less likely to achieve TH. The association between specific microbiota, wound healing gene programs, and LN may suggest future therapeutic targets.
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    Compositional and Temporal Changes in the Gut Microbiome of Pediatric Ulcerative Colitis Patients Are Linked to Disease Course
    (Elsevier, 2018-10-10) Schirmer, Melanie; Denson, Lee; Vlamakis, Hera; Franzosa, Eric A.; Thomas, Sonia; Gotman, Nathan M.; Rufo, Paul; Baker, Susan S.; Sauer, Cary; Markowitz, James; Pfefferkorn, Marian; Oliva-Hemker, Maria; Rosh, Joel; Otley, Anthony; Boyle, Brendan; Mack, David; Baldassano, Robert; Keljo, David; LeLeiko, Neal; Heyman, Melvin; Griffiths, Anne; Patel, Ashish S.; Noe, Joshua; Kugathasan, Subra; Walters, Thomas; Huttenhower, Curtis; Hyams, Jeffrey; Xavier, Ramnik J.; Medicine, School of Medicine
    Evaluating progression risk and determining optimal therapy for ulcerative colitis (UC) is challenging as many patients exhibit incomplete responses to treatment. As part of the PROTECT (Predicting Response to Standardized Colitis Therapy) Study, we evaluated the role of the gut microbiome in disease course for 405 pediatric, new-onset, treatment-naive UC patients. Patients were monitored for 1 year upon treatment initiation, and microbial taxonomic composition was analyzed from fecal samples and rectal biopsies. Depletion of core gut microbes and expansion of bacteria typical of the oral cavity were associated with baseline disease severity. Remission and refractory disease were linked to species-specific temporal changes that may be implicative of therapy efficacy, and a pronounced increase in microbiome variability was observed prior to colectomy. Finally, microbial associations with disease-associated serological markers suggest host-microbial interactions in UC. These insights will help improve existing treatments and develop therapeutic approaches guiding optimal medical care