Researchers at the University of Winnipeg have demonstrated that short-term caloric restriction, initiated during the active phase of acute colitis, partially reprograms both immune and microbial networks in mice. Published in Genes & Nutrition, the study provides a detailed mechanistic look at how dietary energy reduction interacts with inflammation in the gut. By combining transcriptomic and microbiome analyses, the team identified specific pathways where caloric restriction dampens inflammatory signaling while preserving metabolic resilience. The findings suggest that dietary interventions may serve as a non-pharmacological adjunct in managing inflammatory bowel disease, although the study remains preclinical.
The research focused on the dextran sodium sulfate (DSS) model of colitis, a widely used experimental system that induces acute mucosal injury and systemic immune activation. The study aimed to determine whether caloric restriction, applied concurrently with DSS exposure, could attenuate disease severity and shift host transcriptional responses. The investigators hypothesized that reducing caloric intake would partially reduce DSS-induced inflammation and epithelial disruption. To test this, they examined clinical disease activity, histopathology, and molecular changes in the colon and spleen of male C57BL/6 mice.
The experimental design involved thirty-two male mice assigned to four groups: a control group, a caloric restriction group, a DSS-treated group, and a group receiving both DSS and caloric restriction. The caloric restriction protocol involved a 40% reduction in daily food intake, calculated based on average consumption during an acclimation period. Mice in the DSS groups received 2% dextran sodium sulfate in their drinking water for seven consecutive days. This acute exposure was chosen to capture the peak inflammatory phase and early resolution of colitis. Tissue samples were collected on day 9 to assess both localized mucosal injury and systemic immune activation.
Clinical assessments revealed that while caloric restriction did not prevent weight loss or colon shortening, it significantly improved stool consistency and intestinal bleeding scores compared to mice treated with DSS alone. These improvements were consistent from day 2 onward and reached statistical significance on days 6, 7, and 9. Histological analysis showed that DSS treatment caused marked disruption of colonic tissue architecture, including inflammatory infiltration and epithelial damage. Although caloric restriction was associated with modest trends toward reduced epithelial injury, it did not significantly restore overall mucosal architecture or reduce total histopathology scores relative to the DSS group.
Transcriptomic analysis using RNA sequencing provided deeper insights into the molecular effects of caloric restriction. In the colon, DSS treatment elicited a strong pro-inflammatory transcriptional program, characterized by the enrichment of pathways such as cytokine-cytokine receptor interaction, chemokine signaling, and NF-κB signaling. In mice that received concurrent caloric restriction, these inflammatory pathways remained detectable but showed significantly reduced activation. Gene Set Enrichment Analysis indicated a coordinated shift away from inflammation-dominant activity toward programs supporting epithelial renewal and tissue maintenance, including cell cycle regulation and proteasome function. This suggests that caloric restriction helps sustain controlled epithelial proliferation and repair under inflammatory stress.
Systemic immune responses were also modulated by caloric restriction. Spleen weight and white pulp area, which are indicators of systemic immune activation, were significantly reduced in the caloric restriction group compared to the DSS-only group. Peripheral blood smear analysis further demonstrated that caloric restriction reduced the frequency of hypochromic erythrocytes, a hematological disturbance associated with DSS-induced colitis. These findings indicate that the protective effects of caloric restriction extend beyond the gut to influence systemic immune and hematological parameters.
The study also examined the impact of caloric restriction on the gut microbiota. Stool samples were collected at baseline and after treatment to assess disease-related shifts in microbial composition. Caloric restriction partially mitigated DSS-associated dysbiosis, modestly preserving microbial diversity and functional pathways. While DSS treatment led to the enrichment of taxa associated with inflammatory states, such as Paraprevotella and Lachnospiraceae, the caloric restriction group showed relative increases in potentially beneficial genera like Romboutsia. This preservation of metabolic resilience may contribute to the observed immunomodulatory effects.
To evaluate the translational relevance of these findings, the researchers performed cross-species comparisons with human ulcerative colitis microarray datasets. The analysis confirmed that the DSS mouse model recapitulates the transcriptional signatures of active human ulcerative colitis. Specifically, pathways enriched in DSS-treated mice, such as IL-17 signaling and TNF signaling, were also prominent in active human UC. Importantly, caloric restriction shifted these transcriptional profiles toward a remission-like state, reducing the enrichment of inflammatory pathways. This alignment between mouse and human data strengthens the argument that the molecular changes observed in the DSS model are relevant to human disease.
The study also investigated the INSL5-RXFP4 signaling axis, which has been implicated in colonic energy sensing and fasting responses. The researchers found that INSL5 expression remained unchanged across treatments, while RXFP4 showed only modest down-regulation in active UC. These results suggest that the INSL5-RXFP4 axis is not a major contributor to the acute protective effects of caloric restriction. Instead, the benefits appear to be driven by broader shifts in immune and metabolic pathways. This finding helps narrow down the mechanistic pathways involved in dietary modulation of colitis.
Despite the promising results, the study has several limitations that must be considered. The 40% caloric restriction regimen used in the mice may not be directly translatable to human patients, who often face concerns about unintended weight loss and malnutrition during active disease. The study was conducted exclusively in male mice, which exhibit greater DSS susceptibility than females, and thus the findings may not apply to all sexes. Additionally, the DSS model captures acute mucosal injury but does not fully replicate the chronic, relapsing-remitting course of human ulcerative colitis. The microbiome analyses were based on 16S rRNA sequencing, which provides insights into community structure but not absolute bacterial load.
The authors emphasize that these findings provide mechanistic insight into how dietary constraint influences inflammation-sensitive host and microbial responses. They do not support the immediate clinical implementation of caloric restriction during active disease. Instead, the study highlights the potential of dietary interventions as a non-pharmacological adjunct to modulate intestinal inflammation. Future research should focus on more moderate dietary strategies, such as time-restricted feeding or fasting-mimicking diets, which may offer better feasibility and safety for human patients. Replication in independent cohorts and the inclusion of both sexes will be essential to validate these findings.
This research contributes to the growing body of evidence linking diet and inflammatory bowel disease. By demonstrating that short-term caloric restriction can reprogram immune and microbial networks, the study opens new avenues for exploring dietary therapies. The integration of transcriptomic and microbiome data provides a comprehensive view of how dietary interventions interact with host biology.
The study underscores the complexity of the relationship between diet and inflammation. While caloric restriction showed partial protective effects, it did not completely reverse the damage caused by DSS. The preservation of microbial functional resilience and the shift toward epithelial repair programs highlight the multifaceted nature of dietary modulation. Further translational studies will be needed to determine the optimal timing, duration, and intensity of dietary restriction for clinical benefit.
Subject of Research: The effects of short-term caloric restriction on immune and microbial networks in acute DSS-induced colitis in mice.
Article Title: Short-term caloric restriction partially reprograms immune and microbial networks during acute DSS-induced colitis
Article References: Hechter, D. T. D., Kisselev, I., McNicol, I. J., & Good, S. V. (2026). Short-term caloric restriction partially reprograms immune and microbial networks during acute DSS-induced colitis. Genes & Nutrition, 21(1), Article 6. https://doi.org/10.1186/s12263-026-00798-9
Image Credits: AI Generated
DOI: 10.1186/s12263-026-00798-9
Keywords: caloric restriction, inflammatory bowel disease, colitis, gut microbiota, transcriptomics, immune response, dextran sodium sulfate, metabolic resilience, epithelial repair, preclinical research, Short-term, caloric
News Source: Morgan Morrow. (November 9, 2026). Caloric Restriction Modifies Immune and Microbial Responses in Acute Colitis. Scienmag.
