Abstract 2794: Consumption of dietary fiber correlates with a significant increase in a-diversity in the intestinal Microbiome of allo-HCT recipients and with lower GVHD-lethality in pre-clinical models
Authors: Paredes Jenny , Dai Anqi , Ramos Ruben J. Faustino , Adintori Peter , Fei Teng , Nguyen Chi , Elias Harold , Victor Kristen , Ghale Romina , Pohl Charlotte , Gradissimo Ana , Cross Justin , Miltiadous Oriana , Peled Jonathan , da Silva Marina Burgos , van den Brink Marcel RM 
Published: March 2024

Abstract
Background: Graft-versus-host disease (GVHD) is associated with a decrease in intestinal microbiota and beneficial short-chain fatty acids (SCFAs). Dietary fiber can modulate the intestinal microbiome and SCFA production which effect intestinal epithelium health and immunity. Therefore, we hypothesized that a high-fiber diet in recipients of an allogeneic hematopoietic cell transplantation (allo-HCT) could result in an increase of beneficial commensals, concentrations of SCFAs, and decreased risk of GVHD.
Methods: We evaluated dietary data and fecal samples of allo-HCT patients receiving unmodified grafts (n=95) at MSKCC (day -10 to day +30 relative to allo-HCT) and correlated microbial α-diversity (16s rRNA, n=568 samples) with fiber intake and acute GVHD in No-GVHD (n=30), Non-LGI-GVHD (GVHD except lower gastrointestinal tract, n=41), and LGI-GVHD patients (lower gastrointestinal tract GVHD, n=24).We tested concentrations of cellulose fiber (0%, 6%, 12% and 40%) in a GVHD mouse model (C57BL/6J into BALB/c) to assess survival, microbial composition (shotgun sequencing n=180; n=30 per group), cecal SCFAs concentrations (GC-MS n=24, n=8 per group), and lastly, T cell subsets (Th1/Th17/Tregs) and colonic epithelial MHC-II expression (flow cytometry n=54, n=18 per group).
Results: In allo-HCT patients, fiber intake correlated positively with microbial α-diversity (R=0.3, p=0.04), especially in the LGI-GVHD group (p=0.007). Additionally, patients with high fiber intake had higher microbial α-diversity compared to the low fiber cohort (p&lt;0.0001).GVHD mice receiving a fiber-rich diet (12%), compared to 0% and 6%, had a higher microbial α-diversity (p=0.01); reduced GVHD lethality (p=0.02); and a decrease in the Enterococcus sp. (p=0.004) and Akkermansia sp. (p=0.01) abundance; taxa which are associated with worse overall survival and increased risk of lethal GVHD. In contrast, compared to 12%, the 40% fiber diet resulted in worse survival (p=0.002), lower α-diversity (p=0.05) and a higher abundance of Bifidobacterium sp. (p&lt;0.0001).Cecal butyrate in GVHD mice was higher in response to the 12% vs. the 0% (p=0.01) and 6% (p=0.05) fiber diets. Mice treated with12% fiber displayed higher number of Tregs (CD4+CD25+FOXP3+), than those with 0% (p=0.001) and 6% (p=0.02); and a lower expression of MHC-II in epithelial cells (EpCAM+CD45-) vs. 0% fiber (p=0.02).
Conclusions: We demonstrated that a higher fiber intake in allo-HCT patients is associated with an increase in α-diversity; especially in LGI-GVHD patients. In a pre-clinical GVHD-model, optimal fiber consumption (12% cellulose) leads to an increase in α-diversity, a decrease in pathogen relative abundance, increased T-regulatory cells, and a decrease in GVHD lethality. These results suggest that dietary fiber could be utilized to prevent GVHD.
Citation Format: Jenny Paredes, Anqi Dai, Ruben J. Faustino Ramos, Peter Adintori, Teng Fei, Chi Nguyen, Harold Elias, Kristen Victor, Romina Ghale, Charlotte Pohl, Ana Gradissimo, Justin Cross, Oriana Miltiadous, Jonathan Peled, Marina Burgos da Silva, Marcel RM van den Brink. Consumption of dietary fiber correlates with a significant increase in a-diversity in the intestinal Microbiome of allo-HCT recipients and with lower GVHD-lethality in pre-clinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2794.