Gut microbe molecule butyrate proposed as shield for children’s sepsis kidney injury

Sepsis-associated acute kidney injury is one of the most feared complications in critically ill children. Those who develop it spend longer stretches in the pediatric intensive care unit and face higher mortality than children whose kidneys escape damage, and pediatric acute kidney injury may raise the later risk of chronic kidney disease and hypertension. In an editorial published in World Journal of Pediatrics, a team of researchers argues that a molecule made by gut bacteria—butyrate—deserves systematic attention as a possible protective mediator linking the intestine to the kidney, while conceding that direct evidence in children remains extremely limited.

The authors, led by Xing-Ting Zhang, Ke-Xin Zhang, Yan-Jun Wu, Xing Gao, Tong Lin, Felix W. Leung, Yong-Yan Shi and Hao Chen, frame their argument around a stubborn therapeutic gap. Despite advances in pediatric sepsis care, no specific therapy directly prevents or reverses kidney injury in patients with sepsis-associated acute kidney injury. The reason, they contend, is the sheer complexity of the condition, which involves dysregulated inflammation, immune dysfunction, endothelial injury, microcirculatory disturbance, metabolic reprogramming, mitochondrial stress and maladaptive repair. These mechanisms suggest that kidney injury during sepsis may be driven by upstream and systemic processes beyond the kidney itself—an opening, they argue, for interventions aimed at the gut.

The gut–kidney axis offers one such upstream perspective. Critical illness, sepsis, antibiotic exposure, fasting and impaired enteral nutrition can disrupt the gut microbiome and the intestinal barrier, particularly in infants and young children, whose gut microbiota undergo substantial maturation during the first years of life. In this context, butyrate is biologically plausible: as a microbiome-derived short-chain fatty acid, it links microbial metabolic function with epithelial barrier maintenance, immune regulation and tissue repair. The editorial proposes that butyrate deserves attention as a testable microbiome-derived mediator of the gut–kidney axis in pediatric patients with sepsis-associated acute kidney injury.

The starting point is dysbiosis. In pediatric sepsis, gut microbial imbalance may arise from critical illness, shock, intestinal hypoperfusion, broad-spectrum antibiotics, fasting and impaired enteral nutrition. These factors can reduce microbial diversity, deplete beneficial anaerobic commensals, promote pathobiont expansion and alter microbial metabolic capacity. Pediatric studies have reported intestinal dysbiosis early in sepsis, with reduced microbial diversity over time and significant alterations in the gut microbiota and metabolome in children with sepsis or septic shock. The authors argue that dysbiosis in this setting should not be viewed merely as a secondary consequence of critical illness but as a potential contributor to host-response dysregulation.

How might intestinal changes reach the kidney? Once the intestinal barrier is weakened, endotoxins, bacterial products and other microbe-associated molecular patterns may be translocated into the circulation, contributing to endothelial injury, microcirculatory dysfunction, oxidative stress and renal tubular injury. The key issue, the editorial stresses, is not microbial taxonomy alone but whether the loss of microbial metabolites that normally support barrier integrity and immune homeostasis creates a mechanistic bridge between intestinal disruption and kidney injury. Butyrate is of particular interest because it reflects microbial metabolic function and acts on epithelial and immune pathways relevant to the condition.

Butyrate is a major short-chain fatty acid produced by anaerobic gut bacteria through the fermentation of non-digestible dietary fibers, and its abundance depends on substrate availability and the metabolic activity of butyrate-producing bacteria. It serves as an energy substrate for colonocytes, supports mucus and tight junction integrity, and influences inflammatory signaling through histone deacetylase inhibition and the activity of short-chain fatty acid receptors, including GPR41, GPR43 and GPR109A. Evidence from kidney injury models supports the broader concept: in ischemia–reperfusion-induced acute kidney injury, gut bacteria-derived products and short-chain fatty acids reduce renal dysfunction, inflammation and tubular injury, and fiber-derived microbial metabolites have been reported to protect against acute kidney injury through G protein-coupled receptors and histone deacetylase inhibition. Recent preclinical work has begun to link reduced butyrate levels with sepsis-related kidney injury and to suggest that butyrate supplementation may attenuate renal damage, though its relevance to critically ill children still needs to be established.

The editorial lays out three potential protective mechanisms. The first acts at the intestinal barrier: experimental studies have shown that butyrate enhances epithelial barrier function through AMP-activated protein kinase activation and upregulation of tight junction proteins such as claudin-1. In a cecal ligation and puncture model of sepsis, sodium butyrate alleviated intestinal mucosal injury, reduced intestinal permeability, restored claudin-1 and ZO-1 expression and improved survival. Protecting gut barrier function, the authors suggest, may be an important upstream strategy for reducing kidney injury in pediatric patients, although direct pediatric evidence is still needed.

The second mechanism concerns immune rebalancing rather than simple anti-inflammatory suppression. During sepsis, excessive activation of innate immune cells, cytokine release, endothelial injury, complement activation and leukocyte recruitment can converge on the kidney, promoting renal microvascular dysfunction and tubular epithelial injury. Butyrate can act as a histone deacetylase inhibitor and as a ligand for short-chain fatty acid receptors: experimental studies show it promotes colonic regulatory T cell differentiation and supports the Treg pool, while related work suggests microbial metabolites can facilitate peripheral Treg generation through histone deacetylase inhibition. Activation of GPR109A by butyrate promotes anti-inflammatory properties in macrophages and dendritic cells and induces Tregs and interleukin-10-producing T cells. At the signaling level, sodium butyrate suppresses lipopolysaccharide-induced macrophage inflammation by inhibiting nuclear factor-κB and NLRP3 inflammasome pathways and alleviates LPS-induced kidney injury through inhibition of Toll-like receptor 2/4-related signaling. These data suggest butyrate may attenuate the condition by limiting uncontrolled inflammatory amplification while preserving immune regulatory pathways, though age-specific testing in children is needed.

The third mechanism targets local tubular injury. Renal tubular epithelial cells are highly energy-demanding and vulnerable to sepsis-induced metabolic stress: during sepsis they may undergo impaired fatty acid oxidation and oxidative phosphorylation, ATP depletion, reactive oxygen species accumulation and defective mitochondrial quality control. Human data also suggest sepsis-associated acute kidney injury is associated with mitochondrial DNA damage and reduced mitochondrial mass in the kidney. In experimental kidney injury models, butyrate or sodium butyrate has been associated with reduced inflammation, oxidative stress, apoptosis and structural renal damage, and sodium butyrate has been reported to alleviate renal ischemia–reperfusion injury through the HES1/PPARα pathway and to improve mitochondrial dysfunction through activation of renal mitochondrial AMPK/PGC-1α signaling in diabetic kidney disease models. More directly, in an LPS-induced sepsis-associated acute kidney injury model and in LPS-treated HK-2 cells, butyrate attenuated kidney injury, reduced NLRP3, STING and gasdermin D expression, and mitigated tubular cell pyroptosis through the STING–GSDMD axis. Whether butyrate directly modulates ferroptosis, another regulated cell death pathway implicated in the condition, remains unknown.

The authors are careful about what their hypothesis cannot yet claim. Butyrate is not an established therapy for pediatric sepsis-associated acute kidney injury, and most supportive findings come from experimental sepsis or non-septic renal injury models. Extrapolation to children is uncertain because the gut microbiome and its metabolic output develop with age and are further altered by critical illness and treatment. They call for prospective pediatric studies collecting serial stool and blood samples from early sepsis patients through acute kidney injury onset and recovery, assessing butyrate and other short-chain fatty acids alongside the microbiome, inflammatory responses, renal injury markers and kidney function, while accounting for disease severity, hemodynamic status and treatment exposure—since hospitalization, antimicrobial therapy, fasting and enteral nutrition can independently reshape the intestinal environment. Such work may determine whether butyrate depletion precedes acute kidney injury or merely reflects greater illness severity.

Clinical translation also faces delivery and safety hurdles. Most colonic butyrate is metabolized by the intestinal mucosa and liver, and only about 2% reached the systemic circulation in a stable isotope study in humans. Adult studies have used microencapsulated sodium butyrate and the prodrug tributyrin to improve oral delivery, but tributyrin shows substantial pharmacokinetic variability and may require a high capsule burden, while evidence for microencapsulated sodium butyrate comes mainly from stable adults. Delivery may be less predictable in critically ill children because of delayed gastric emptying and interrupted enteral feeding. Safety must also be established: high luminal concentrations cause intestinal injury in newborn rats, butyrate exposure has been associated with necroptotic injury in immature intestinal models, and its anti-inflammatory effects may be stage dependent because sepsis can involve both hyperinflammation and immune suppression. The editorial concludes that butyrate-directed interventions should proceed only after a safe dose range, appropriate treatment window, feasible delivery strategy and clear temporal relationship with pediatric sepsis-associated acute kidney injury have been established.

Subject of Research: A hypothesis that butyrate, a microbiome-derived short-chain fatty acid, may protect children's kidneys in sepsis-associated acute kidney injury through the gut–kidney axis.

Article Title: Butyrate in pediatric sepsis-associated acute kidney injury: hypothesized protection through the gut–kidney axis

Article References: Zhang, X.-T., Zhang, K.-X., Wu, Y.-J., Gao, X., Lin, T., Leung, F. W., Shi, Y.-Y., & Chen, H. (2026). Butyrate in pediatric sepsis-associated acute kidney injury: hypothesized protection through the gut–kidney axis. World Journal of Pediatrics. https://doi.org/10.1007/s12519-026-01115-5

Image Credits: AI Generated

DOI: 10.1007/s12519-026-01115-5

Keywords: butyrate, pediatric sepsis, acute kidney injury, gut-kidney axis, gut microbiome, short-chain fatty acids, intestinal barrier, inflammation, mitochondrial dysfunction, pyroptosis, clinical translation, World Journal of Pediatrics