Fat, long dismissed as merely a passive storage depot for excess calories, has undergone a radical reevaluation in the scientific community. Once seen simply as biological padding, adipose tissue is now understood as a highly active endocrine organ, intricately involved in hormonal regulation, nervous system communication, and immune system modulation. This evolving understanding has recently been propelled even further by groundbreaking research from Stanford Medicine, revealing yet another surprising dimension of fat’s biological influence—its direct role in the debilitating intestinal scarring characteristic of Crohn’s disease.
In a compelling study published in Cell on September 17, 2025, Stanford researchers have shifted the spotlight to an abnormal type of fat, colloquially termed “creeping fat,” which aggressively envelops the intestines in Crohn’s patients. Unlike benign adiposity, this pathological fat contributes directly to the formation of intestinal fibrosis, a scarring process that stiffens and narrows the bowel in what are known clinically as strictures. This insight reframes creeping fat from a mere symptom of disease to an active player exacerbating the progression of Crohn’s, offering novel molecular targets for intervention that were previously unconsidered.
Crohn’s disease, a perplexing and chronic inflammatory condition of the gastrointestinal tract, generally emerges in adolescence or early adulthood. Patients suffer from a cascade of symptoms—including relentless abdominal pain, diarrhea, malnutrition, and profound fatigue—that deeply impact quality of life. While anti-inflammatory treatments can sometimes achieve remission, a significant subset of patients inevitably progress to develop strictures, a severely fibrotic thickening that impairs intestinal function. Surgical excision remains the primary recourse for strictures; however, this approach is far from ideal, given its invasive nature and the high rate of recurrence.
The challenge in managing strictures lies not only in their physical toll but in their biological complexity. Prior investigations noted the consistent presence of creeping fat adjacent to these scarred intestinal segments, but the mechanistic links remained elusive. This new study, led by pediatric surgeon Jeong Hyun and surgeon-scientist Michael Longaker, probes these mechanisms with unprecedented rigor, combining human tissue analysis and sophisticated animal modeling. Their work reveals that creeping fat houses specialized fibroblasts that are highly responsive to mechanical stress—a factor previously underappreciated in Crohn’s pathogenesis.
Detailed genetic and molecular profiling of fibroblasts within creeping fat tissue discloses a fascinating mechanosensitivity: these cells detect and respond to mechanical strain emanating from the tense, inflamed intestine. This response includes the production of extracellular matrix components, the fundamental constituents of fibrotic scar tissue. Crucially, these activated fibroblasts concentrate at the interface where fat meets intestine, suggesting a localized, dynamic interplay that intensifies tissue stiffening. This insight overturns the conventional mucosa-centric view of Crohn’s, which has historically focused on immune-driven inflammation within the innermost bowel layers.
Equally groundbreaking is the development of an animal model that faithfully recapitulates the human Crohn’s phenotype, including hallmark creeping fat and stricture formation. In this model, mechanical tension of the intestine synergizes with chronic inflammation to activate the fibroblasts in adjacent fat, thereby fueling fibrosis. Such a paradigm foregrounds the role of biomechanical forces alongside immune dysregulation—an integrative perspective that better explains the complex progression of the disease.
The molecular pathways elucidated in this process include the highly conserved YAP/TAZ signaling cascade, known to mediate cellular responses to mechanical stimuli across diverse tissues. Longaker’s laboratory, previously engaged in exploring scar formation in skin, identified that inhibiting YAP/TAZ signaling in fat-resident fibroblasts drastically reduces the fibrotic response in the intestines of diseased mice. This discovery not only implicates a specific, druggable target but also aligns intestinal fibrosis with broader principles of mechanically induced scarring, revealing a potential therapeutic avenue previously untapped in Crohn’s management.
These insights carry profound clinical implications. Current anti-inflammatory regimens address only one facet of Crohn’s pathophysiology—immune activation—while ignoring the potent feedback loop established by creeping fat and mechanosensitive fibrosis. Patients who experience escalating fibrosis despite medication highlight this gap in treatment strategies. The identification of fat-derived fibroblasts as drivers of strictures points toward therapies that could intercept scarring processes before surgery becomes necessary, potentially transforming patient outcomes.
The emotional and physical burden borne by Crohn’s patients is immense. Jeong Hyun, who regularly performs surgeries to excise fibrotic strictures, describes the experience of his patients as one marked by unpredictability and chronic suffering. The inability to control symptom flare-ups or disease progression inflicts a dual hardship—bodily and psychological. This research not only illuminates a path forward scientifically but also holds promise for ameliorating a disease that, until now, offered limited avenues beyond invasive interventions.
Furthermore, the notion of “outside-in” signaling introduced by this study—that inflammation and mechanical forces permeate the full thickness of the bowel wall and the surrounding fat—is a significant conceptual advance. It challenges the prevailing “inside-out” dogma, which confined pathogenetic considerations to layers closest to the intestinal lumen. Recognizing the mesentery and creeping fat as bioactive sites reshapes the therapeutic landscape and necessitates a broader approach to drug development.
This finely detailed exploration also underscores the power of multidisciplinary collaboration. Contributions from institutions beyond Stanford, including Case Western Reserve University and the Icahn School of Medicine at Mt. Sinai, as well as support from a spectrum of funding agencies, illustrate the collective effort required to tackle complex diseases like Crohn’s. Such synergy between surgical insight, molecular biology, and translational research is key to accelerating progress in difficult clinical arenas.
In conclusion, the Stanford-led study reinvents our understanding of fat’s role in Crohn’s disease, transforming creeping fat from a passive marker of disease into a mechanosensitive culprit driving fibrosis. The revelation that biomechanical forces and associated signaling pathways contribute crucially to intestinal scarring underscores the urgency of developing targeted anti-fibrotic therapies. If successful, these could revolutionize care, reducing the need for repeated surgeries and profoundly improving the lives of millions affected by this relentless disease.
Subject of Research: Animals
Article Title: Creeping fat-derived mechanosensitive fibroblasts drive intestinal fibrosis in Crohn’s disease strictures
News Publication Date: 17-Sep-2025
Web References: https://profiles.stanford.edu/jeong-hyun, https://profiles.stanford.edu/michael-longaker, https://profiles.stanford.edu/khristian-bauer-rowe-ramos, https://med.stanford.edu/
References: Study published in Cell, September 17, 2025
Keywords: Crohn disease, inflammatory bowel diseases, intestinal fibrosis, creeping fat, fibroblasts, mechanosensitive signaling, YAP/TAZ pathway, intestinal strictures
