Saliva may be able to predict severity of cirrhosis

Cirrhosis is a disease of the liver in which healthy liver tissue is replaced with scar tissue, preventing the liver from properly functioning. Scientists at Virginia Commonwealth University found that changes in the microbiome of saliva were found in cirrhosis patients in comparison to individuals without the disease.

The scientists analyzed the bacterial contents of both stool samples and salivary samples from patients with varying degrees of cirrhosis as well as healthy controls.  Previous studies had shown that cirrhosis patients had altered fecal microbiomes and in this study, they found that patients also had altered salivary microbiomes. 102 individuals with cirrhosis were studied including 43 of them who previously had hepatic encephalopathy (HE), a severe result of liver disease that results in confusion, coma, and can even lead to death.

Patients who previously had HE saw a decrease in bacteria in their saliva that were normally in the body and an increase in bacteria that were pathogenic, including Enterobacteriaceae and Enterococcaceae, Similar results were found in their stool samples. Of the 102 patients, 38 of them were hospitalized within 90 days of the study.  Those 38 individuals had greater salivary dysbiosis than those who were not hospitalized.

They also looked at an additional 43 individuals without cirrhosis and 43 with cirrhosis and looked at the inflammatory profile in the saliva. They found that the cirrhosis patients had immune deficiencies that were similar to that in the gut.

This study showed that the salivary microbiome was similar to the fecal microbiome in patients with cirrhosis. This provides evidence that you may be able to use saliva to predict the disease severity of patients with the disease as well as providing a tool for testing treatment options for patients with the disease. 

Microbiome link between cystic fibrosis and liver disease

Scientists have discovered a possible link between the microbiome and liver disease in individuals with cystic fibrosis.  Cystic fibrosis (CF) is a genetic disease that can be fatal and affects 30,000 people in the United States with another 1,000 diagnosed every year. While pulmonary disease is the most common cause of death in patients with CF, liver disease results in 2.5% of deaths and occurs in up to 72% of patients with the disease.  Approximately 5-7% of  these liver diseased CF patients have cirrhosis, a disease marked by the replacement of healthy liver tissue with scar tissue, preventing the liver from properly functioning.

A team of scientists from University of Colorado Medical Center recently published a study pertaining to CF patients with liver disease  in PLoS One. They studied 11 adolescents with CF and cirrhosis as well as 19 age-matched adolescents with CF without liver disease. They found that the two groups of patients had different gut microbiomes, leading the researchers to believe that there is communication between the gut bacteria and the liver, specifically in CF patients.

Patients with CF and cirrhosis had more severe lesions in their intestines than those without liver disease. Also, specific bacteria were less abundant in cirrhosis patients (e.g. Bacteroidetes) and others more abundant (e.g. Firmicutes) compared to CF patients without liver disease.    Similar ratios have been seen in other studies of liver disease and obesity.  However, we must remember that in complex diseases like CF, the microbiome is only one component of a very dynamic ailment, and at least one other disease study has measured the opposite Bacteroidetes/Firmicutes abundances.

Despite differences in previous studies and the lack of a mechanism relating the microbiome to cirrhosis, this identification of bacterial differences between CF patients with and without liver diseases is promising. The authors of the study point out that the sample size was small and this was only meant to be a pilot study but further longitudinal studies may now be warranted to investigate the development of cirrhosis in cystic fibrosis patients.