Gut Microbes Not Essential in Liver Regeneration

After partial hepatectomy, the liver does not need an environment rich in microbes and microbial products to regenerate, a Swiss team reports.

In an abstract presented April 24 at the 2015 International Liver Congress in Vienna, Austria, Thomas Malinka and colleagues at Bern University in Bern, Switzerland report on a mouse study of liver regeneration after such surgery—a “very complex process that involves a variety of different liver cell types,” via cytokine- and growth-factor-mediated pathways.”

It had previously been thought that a liver will not regenerate unless the gut microbiota is present.

“Bacterial products and LPS circulate in the portal blood stream directly through the hepatic sinusoids and have been proposed to initiate liver regeneration by activation of parenchymal ad non-parenchymal cells in the liver after partial hepatectomy,” Malinka wrote.

To test that suppositions, the team performed liver surgery on germ-free mice and a set of mice colonized with altered schaedler flora.

The surgery was done in sterile conditions and the researchers removed 2/3 of the animals’ livers.

They found that liver injury and survival did not significantly differ in the 2 groups. Liver regeneration rates also showed no significant difference.

They concluded that “liver regeneration after partial hepatectomy is not impaired in the absence of microbes and microbial products” a finding that contrasts with previous studies. “The gut microbiota is not an essential for the priming or maintenance of live regeneration,“ they wrote.