The study, published in Microbiology, produced Lactobacillus probiotics that were specially designed to express a CLA producing enzyme from other bacteria. The researchers said that their findings could lead to specialised probiotics that have a role in the prevention or treatment of weight management issues.
“These data demonstrate that a single gene (encoding CLA isomerase) expressed in an intestinal microbe can influence the fatty acid composition of host fat,” said the researchers, from the Alimentary Pharmabiotic Centre (APC), Cork, Ireland.
The scientists successfully cloned and overexpressed a gene known to produce CLA from Propionibacterium acnes in Lactococcus lactis bacteria, resulting in a probiotic strain that achieved conversion rates of more than 50 percent of linoleic acid to t10, c12 CLA – a specific type of CLA known to be beneficial in fat tissues.
“To our knowledge the first report to demonstrate that oral administration of a genetically modified t10, c12 CLA-producing strain (containing the single gene for t10, c12 CLA production) results in modulation of the fatty acid composition of the host, including significantly higher concentrations of t10, c12 CLA in adipose tissue, which is directly attributable to the presence of the t10, c12 CLA isomerase gene,” said the researchers.
The authors noted that evidence is emerging to support the concept that the microbiota can have “profound effects on human health and disease, involving complex host–bacteria interactions that are as yet poorly understood.”
They noted that the gut microbiota is important to the host with regard to metabolic functions, providing nutrients and may offer some resistance to bacterial infections. In addition, the microbiota has been shown to have an effect on disease processes outside the gut.
“CLA has already been shown to alleviate non-alcoholic fatty liver disease that often accompanies obesity. Therefore, increasing levels of CLA in the liver by ingestion of a probiotic strain is of therapeutic relevance," said Dr Catherine Stanton one of the lead authors of the study.
"Furthermore, fat is not an inert layer around our bodies, it is active and pro-inflammatory and is a risk factor for many diseases, including cancers. The work shows that there is potential to influence this through diet-microbe-host interactions in the gut," she explained.
The researchers investigated whether the recombinant Lactobacillus, expressing CLA isomerase from Propionibacterium acnes could influence the fatty acid composition of bodily tissues in a mouse model.
Linoleic-acid-supplemented diets were fed in combination with either a recombinant t10, c12 CLA-producing Lactobacillus or a control strain, to mice for 8 weeks.
Stanton and colleagues reported that ingestion of the strain expressing the CLA isomerase was associated with a 4-fold increase in t10, c12 CLA in the fat tissues of mice when compared with mice that received the non-CLA-producing strain.
“This study demonstrates that t10, c12 CLA production occurred in vivo when a recombinant
Lactobacillus strain harbouring the gene encoding t10, c12 CLA isomerase was administered to mice,” they said.
"We need to further investigate the effects of CLA-producing bacteria on human metabolism, but our work so far certainly opens up new possibilities for the use of probiotics for improvement of human health," added Dr Stanton.
"It is possible that a CLA-producing probiotic may also be able to keep colon cancer cells in check. All our findings to date demonstrate that the metabolism of gut bacteria can modulate host cell activity in ways that are beneficial to the host," she said.
Published online ahead of print, doi:10.1099/mic.0.043406-0
“Recombinant lactobacilli expressing linoleic acid isomerase can modulate the fatty acid composition of host adipose tissue in mice”
Authors: E. Rosberg-Cody, C. Stanton, L. O’Mahony, R. Wall, F. Shanahan, E.M. Quigley, G.F. Fitzgerald, R.P. Ross