The research, published in BMC’s open access journal Microbiome, follows on from previous research found mice with lupus had lower levels of the Lactobacillus family of bacteria in their microbiome make-up. Now the same team have reported that several strains of Lactobacillus found in yoghurt and other dairy could reduce lupus severity and prevent certain complications associated with the condition by altering gut bacteria.
"In our 2014 paper, we found that mice with lupus had decreased amounts of Lactobacillus, which led to our hypothesis that adding this bacteria could ameliorate disease symptoms," said Dr Xin Luo from Virginia Tech.
Luo added that in the previous work she and her colleagues also found that the mice had a ‘leaky gut’ – a condition that affects the intestinal lining and can lead to inflammation and inflammatory conditions.
"Probiotics, such as Lactobacillus, work by patching up and reversing the leaky gut,” she said – noting that the new study demonstrates the mechanisms behind the previously identified association between lupus and Lactobacillus.
Lupus and the microbiome
Lupus is an autoimmune disease that can cause chronic fatigue, joint pain, rash, fever, renal failure.
The new study focuses specifically on lupus nephritis, or inflammation of the kidney that is caused by lupus.
According to the US National Resource Center on Lupus, lupus nephritis usually develops within the first five years after symptoms start, and as many as 40% of all people with lupus, and up to two-thirds of children with the disease, will develop kidney complications.
“Using a classical model of lupus nephritis, MRL/lpr, we found a marked depletion of Lactobacillales in the gut microbiota,” wrote the team. “Increasing Lactobacillales in the gut improved renal function of these mice and prolonged their survival.”
They used a mixture of 5 Lactobacillus strains (Lactobacillus oris, Lactobacillus rhamnosus, Lactobacillus reuteri, Lactobacillus johnsonii, and Lactobacillus gasseri), however it was found that “L. reuteri and an uncultured Lactobacillus sp. accounted for most of the observed effects.”
Lactobacillus treatment contributed to an anti-inflammatory environment by decreasing IL-6 and increasing IL-10 production in the gut, the team added.
Luo added that the Lactobacillus was only found to affect female mice and not males – noting that lupus is 10 times more prevalent in females than in males.
"We think that testosterone is suppressing the effect of the healthy bacteria. Before our study, researchers had never looked at male hormones suppressing the probiotic effect before,” she said.
Although the research was limited to mice with lupus and kidney inflammation, and more work would need to be done to determine whether Lactobacillus has the same effect in humans, Luo emphasized that yogurt and probiotic supplements are considered safe.
"If a lupus patient is female and also has kidney inflammation, there would be no harm in adding yogurt or a probiotic supplement to the diet," she said.
Furthermore, now the researchers have identified the ‘good’ bacteria that affects the severity of lupus, they hope to turn their attention to other areas of research.
"The next question is, 'Are there bad bacteria that can be detrimental to the disease?' " Luo asked. "If that can be found, we can target the bad bacteria and remove them to ameliorate disease symptoms."
Published online, Open Access, doi: 10.1186/s40168-017-0300-8
“Control of lupus nephritis by changes of gut microbiota”
Authors: Qinghui Mu, et al