Scientists seem to have accomplished a great feat in diagnosing liver disease. A team of scientists have created a novel microbiome-based diagnostic tool that identifies liver fibrosis and cirrhosis over 90 per cent of the time in human patients.
The non-invasive method, with the accuracy of the best physicians, quickly and inexpensively, developed by a collaborative team of Salk Institute and UC San Diego scientists could lead to improved patient care and treatment outcomes for liver disease.
The method, as detailed in Cell Metabolism, relies on an algorithm to analyse patient stool samples that contains traces of what lives in the gut."The microbiome is a dynamic living sensor of small changes in health and disease in the body, and as such, it provides an accurate readout of body health," says Salk Professor Ronald Evans, co-corresponding author and holder of the March of Dimes Chair.
"Because this diagnostic is fast and low-cost, it could be something that becomes widely used, especially in the many areas that lack speciality clinics and physicians. Simply said, it could be a real game changer, with world-wide implications."
Chronic liver disease represents a major global public health problem affecting an estimated 844 million people, according to the World Health Organization. It is among the top causes of mortality in Australia, the UK and the United States. At the same time, it is both difficult to manage and there is no FDA-approved anti-fibrotic liver therapy. The microbiome—a complex collection of microbes that inhabit the gut—may be an unexpected indicator of health.
Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease globally and can progress to liver fibrosis and cirrhosis and potentially cancer, as the liver starts to experience scarring and cell death. But diagnostic tools for liver fibrosis and cirrhosis are lacking. Biopsies are invasive and can miss injured regions of the liver, and MRIs are expensive and are often not available in rural areas. To address these challenges, the research team explored the microbiome as a way to meet the urgent need for a new test to identify patients at risk.
"We sought to develop a universal, non-invasive test for liver fibrosis and cirrhosis based on a 'microbiome signature' of the disease," says Michael Downes, a Salk senior staff scientist and co-author of the study.
Using data from microbiome genetic profiling and from metabolites from the stool samples, the researchers discovered a microbiome signature that was associated with a cirrhosis diagnosis with 94 percent accuracy. The microbiome signature could also determine the stage of liver fibrosis, which could allow doctors to grade patients based on their stage of the disease and improve treatment strategies.
"These findings demonstrate that it is possible to use machine learning to identify a universal signature that can be used for accurate diagnosis of a disease, such as liver cirrhosis," says Tae Gyu Oh, first author of the paper and a postdoctoral researcher in the Evans lab.
The researchers then applied their microbiome signature to two independent populations of patients from China and Italy. The team's signature could accurately identify cirrhosis in over 90 percent of patients, which validates the power and accuracy of the algorithm across different genetics and diets.
"I think the power of using the microbiome as a diagnostic tool is only starting to be realised," says Rohit Loomba, co-corresponding author and director of the NAFLD Research Center at the UC San Diego School of Medicine
In the future, the scientists will examine the causal link between the microbiome and liver disease by testing whether restoring parts of the microbiome leads to regression of the disease or removing certain bacteria makes it worse. The team also hopes this approach can be used to characterise additional diseases, such as inflammatory bowel disease, colon cancer, Alzheimer's and other diseases shown to be likely affected by a dysregulated.
