NTU-Led Study Identifies Stool Biomarker Angptl4 as Early Indicator of Gut Barrier Dysfunction in Fatty Liver Disease
Key Insights
An international team led by NTU Singapore has identified faecal Angptl4 as a potential stool biomarker for gut barrier dysfunction, an early contributor to metabolic dysfunction-associated steatotic liver disease (search) (MASLD).
The study, published in Nature Communications, used mouse models and clinical data from three Asian patient cohorts in Thailand, China, and India to validate the findings across diverse populations.
Researchers found that faecal Angptl4 levels rise alongside gut microbial imbalance and metabolic dysfunction, offering a simpler, non-invasive monitoring method compared to blood markers.
A research team led by Nanyang Technological University, Singapore (NTU Singapore) has identified a stool-based protein biomarker that could enable earlier detection of gut barrier dysfunction—a poorly understood precursor to metabolic liver disease. The findings, published in Nature Communications on 22 May, center on angiopoietin-like 4 (search) (Angptl4), a protein found in the gut that appears to connect diet, gut microbes, and a weakened intestinal barrier in metabolic dysfunction-associated steatotic liver disease (search) (MASLD).
The study was led by Associate Professor Andrew Tan Nguan Soon, Vice-Dean (Innovation and Enterprise) and Provost's Chair in Metabolic Disorders at the Lee Kong Chian School of Medicine (LKCMedicine). "We know what we eat changes the bacteria in the gut, so we intentionally picked these three countries that are very different in their dietary intakes... and, hopefully, similar to that of Singapore. We took faecal samples from patients in the different disease states to measure the protein levels. It turned out to be a very good marker for gut health, unlike blood markers," said Assoc Prof Tan.
A New Perspective on the Gut-Liver Axis
The research challenges the traditional clinical view that fatty liver disease originates primarily in the liver itself. LKCMedicine PhD student Damien Chua, the principal investigator of the research, explained: "Doctors used to think fatty liver primarily affects the liver itself, but actually the damage starts early on in the gut." He added that conventional serum markers from blood samples "do not actually align properly, so they were not as robust as we thought they were. With our biomarkers from faecal samples, we are also able to look at a different aspect of what constitutes a leaky gut."
The mechanism involves Angptl4 contributing to a "leaky gut"—a condition in which the intestinal barrier becomes overly porous, allowing bacteria to travel directly to the liver, where they can trigger inflammation and fat accumulation. The study found that faecal Angptl4 levels increased alongside gut microbial imbalance and metabolic dysfunction.
Multi-Cohort Validation Across Asian Populations
The researchers employed both experimental mouse models and clinical data from three patient cohorts spanning Thailand, China, and India. This cross-population design allowed the team to examine the biological mechanism while assessing whether the findings held across different Asian populations with distinct dietary patterns. The international collaboration included clinicians from Tan Tock Seng Hospital (search) in Singapore and King Chulalongkorn Memorial Hospital in Thailand, with the entire effort spanning three to four years.
Growing Disease Burden in Singapore
The findings carry particular relevance for Singapore, where fatty liver disease represents a mounting public health challenge. According to Annals, the official journal of the Academy of Medicine in Singapore, the local disease burden for non-alcoholic fatty liver disease—the previous term for MASLD—was projected to rise from approximately 1.49 million people in 2019 to 1.80 million by 2030. The condition is frequently under-recognised because many patients remain asymptomatic and do not present with abnormal liver enzyme readings.
Assoc Prof Tan noted the scale of the problem: "Just imagine that 30 per cent or 40 per cent of Singaporeans are developing fatty liver disease—the number is huge and the cost is going to be very high for medical intervention. Looking at stools is an easier way for monitoring patients."
Path Toward Clinical Implementation
The team is now working to streamline the stool test for routine clinical use. Because Angptl4 can already be detected using polymerase chain reaction (PCR) machines commonly found in clinical laboratories, Assoc Prof Tan said the biomarker test could be incorporated into existing diagnostic workflows with relative ease after further validation.
The researchers are also collaborating with partners in China and Thailand to assess how the biomarker changes before and after treatment, while simultaneously working with NTU engineering faculty to develop a microfluidic version of the test. "This could make the test easier to use and more suitable for wider deployment in time," Tan added.
Looking ahead, the team sees potential for integration with Singapore's Healthier SG initiative, which shifts the national healthcare focus from reactive treatment to proactive preventive care. Under existing Healthier SG screening protocols, doctors already collect stool samples using faecal immunochemical test kits for colorectal cancer screening. "We should leverage the test because it is already collecting stool samples and integrating one more test would make it accessible... There is actually a lot more information from faecal material that could be tested," said Assoc Prof Tan.
The findings could help researchers better understand early changes along the gut-liver axis before more serious liver disease develops. Increased gut permeability has also been linked in earlier research to metabolic disorders, autoimmune diseases, and allergies, suggesting broader potential applications for gut barrier assessment.