Featured Research

from universities, journals, and other organizations

Mouth bacteria invade gut in liver cirrhosis patients

Date:
July 24, 2014
Source:
INRA-France
Summary:
Gut microbiota of individuals with liver cirrhosis differ notably from healthy individuals’, research shows, showing a high proportion of oral bacteria. This discovery has allowed researchers to build a non-invasive test for liver cirrhosis, accurate to over 90%. This scientific breakthrough could have applications for other chronic diseases and represents an important step in the research for therapies.

Scientists from INRA in collaboration with a Chinese team found that the gut microbiota of individuals with liver cirrhosis differ notably from healthy individuals', showing a high proportion of oral bacteria. This discovery, published in Nature on 23 June 2014, allowed researchers to build a non-invasive test for liver cirrhosis, accurate to over 90%. This scientific breakthrough could have applications for other chronic diseases and represents an important step in the research for therapies.

Related Articles


Liver cirrhosis is a worldwide prevalent disease. Its main causes are obesity, viral infections (hepatitis) and alcohol. It can lead to cancer, or liver failure, requiring transplantation. It is diagnosed mainly by a liver biopsy, an invasive method, which requires hospitalization and is often contraindicated.

Specific bacterial communities

Scientists from INRA in Jouy-en-Josas joined with a Chinese team to characterize intestinal bacterial communities (gut microbiota) in liver cirrhosis patients. To do so, they analyzed the microbiome (collective genome of gut bacteria) of some 250 individuals, half of which with cirrhosis. By comparing the 2.7 million genes they found in these individuals with previously established gene catalogs, researchers identified 800,000 genes hitherto unknown. Refining their analyses, they determined that 75,000 genes were very differently spread between cirrhotic patients and healthy ones. In terms of bacterial populations, 28 species were more abundant in cirrhotic patients, against 38 species in healthy individuals.

Mouth bacteria in the gut

In cirrhotic patients, researchers found that up to 40% of the intestinal microbiota can be comprised of bacteria that are rare in healthy people; a majority of them were actually usual residents of the mouth. S. Dusko Ehrlich, who led the study at INRA, comments: "A possible explanation is that a deficiency of bile synthesis in liver cirrhosis allows an invasion of the gut by the mouth bacteria."

A reliable non-invasive diagnosis

Scientists created a simple test, based on stool analysis, to identify liver cirrhosis patients by the abundance of only 7 bacterial species. This diagnostic tool is quite promising since it's non-invasive highly accurate (over 90%). Moreover, results show a correlation between the proportion of the gut invaders and the severity of the disease. S. Dusko Ehrlich says: "It could be possible to not only diagnose liver cirrhosis but also determine the stage of its advancement."

Similar microbiota in Chinese and Europeans

As the study was based on a Chinese cohort, scientists also sought to test whether Chinese intestinal microbiota were similar to Europeans'. Thanks to bacterial gene catalogs, they confirmed that healthy Chinese and Europeans harbor microbiota that were largely similar, albeit not identical. Further analyses are needed to confirm that alterations are also similar in liver cirrhosis patients from both populations.

Future studies will be needed to understand the role of the bacteria invading the gut of patients in liver cirrhosis. Preliminary observations indicate that certain bacteria overproduce molecules that are implicated in hepatic encephalopathy, a common complication of liver cirrhosis. A therapeutic strategy would be to inhibit these bacteria; another could target the malfunction of the bile in order to prevent the migration from the mouth to the gut.

The novel findings on gut bacteria changes in liver cirrhosis could provide useful leads for other chronic diseases. Oral bacteria have already been observed to be more abundant in patients with colorectal cancer or with Crohn's disease than in healthy individuals. Controlling and fighting this invasion of the gut from the mouth could prove helpful in treating these serious diseases.


Story Source:

The above story is based on materials provided by INRA-France. Note: Materials may be edited for content and length.


Journal Reference:

  1. Nan Qin, Fengling Yang, Ang Li, Edi Prifti, Yanfei Chen, Li Shao, Jing Guo, Emmanuelle Le Chatelier, Jian Yao, Lingjiao Wu, Jiawei Zhou, Shujun Ni, Lin Liu, Nicolas Pons, Jean Michel Batto, Sean P. Kennedy, Pierre Leonard, Chunhui Yuan, Wenchao Ding, Yuanting Chen, Xinjun Hu, Beiwen Zheng, Guirong Qian, Wei Xu, S. Dusko Ehrlich, Shusen Zheng, Lanjuan Li. Alterations of the human gut microbiome in liver cirrhosis. Nature, 2014; DOI: 10.1038/nature13568

Cite This Page:

INRA-France. "Mouth bacteria invade gut in liver cirrhosis patients." ScienceDaily. ScienceDaily, 24 July 2014. <www.sciencedaily.com/releases/2014/07/140724093708.htm>.
INRA-France. (2014, July 24). Mouth bacteria invade gut in liver cirrhosis patients. ScienceDaily. Retrieved January 26, 2015 from www.sciencedaily.com/releases/2014/07/140724093708.htm
INRA-France. "Mouth bacteria invade gut in liver cirrhosis patients." ScienceDaily. www.sciencedaily.com/releases/2014/07/140724093708.htm (accessed January 26, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, January 26, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Mistakes Should Serve a Lesson Says WHO

Ebola Mistakes Should Serve a Lesson Says WHO

AFP (Jan. 25, 2015) The World Health Organization&apos;s chief on Sunday admitted the UN agency had been caught napping on Ebola, saying it should serve a lesson to avoid similar mistakes in future. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com
Disneyland Measles Outbreak Spreads To 5 States

Disneyland Measles Outbreak Spreads To 5 States

Newsy (Jan. 24, 2015) Much of the Disneyland measles outbreak is being blamed on the anti-vaccination movement. The CDC encourages just about everyone get immunized. Video provided by Newsy
Powered by NewsLook.com
Growing Measles Outbreak Worries Calif. Parents

Growing Measles Outbreak Worries Calif. Parents

AP (Jan. 23, 2015) Public health officials are rushing to contain a measles outbreak that has sickened 70 people across 6 states and Mexico. The AP&apos;s Raquel Maria Dillon has more. (Jan. 23) Video provided by AP
Powered by NewsLook.com
Smart Wristband to Shock Away Bad Habits

Smart Wristband to Shock Away Bad Habits

Reuters - Innovations Video Online (Jan. 23, 2015) A Boston start-up is developing a wristband they say will help users break bad habits by jolting them with an electric shock. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins