A recent study revealed a connection between bacterial blooms of the gut bacteria Ruminococcus … [+]
A recent study by NYU Grossman School of Medicine revealed a correlation between bacterial blooms of the gut bacteria Ruminococcus blautia gnavus and disease flares in women with lupus nephritis, one of the most common and serious disease manifestations occurring in more than 40% of lupus patients. A quarter of those individuals may experience end-stage kidney disease, which may require regular blood dialysis or kidney transplantation.
The study, which lasted four years and included 16 women of different racial backgrounds, found that five women experienced R. blautia gnavus bacterial blooms at the same time as lupus attacks.
Lupus is a systemic autoimmune disease characterized by harmful inflammation that affects various organs, such as the kidneys, joints, skin, and blood vessels, affecting approximately 1.5 million Americans and more than 5 million worldwide. Lupus is more common in women than men, and African-American women are three times more likely to get lupus than white women. Lupus is also more common in Hispanic, Asian, and Native American women.
The study used stool and blood samples from lupus patients treated at NYU Langone, with all participants closely monitored for disease flare-ups. The results were compared to 22 healthy female volunteers of similar age and racial background who did not have lupus.
The findings, published in the Annals of Rheumatic Diseases, identified 34 genes associated with the growth of the bacteria in individuals with inflammation. While the specific causes of lupus remain unknown, one hypothesis is that bacterial imbalances drive inherited genetic factors responsible for the disease.
The study also examined the binding of immune system antibodies to structures in the bacterial wall. These antibodies showed a strong affinity for specific bacterial lipoglycan molecules known to cause inflammation. These lipoglycans were found to be predominant in R. blautia gnavus strains in lupus patients, but not in healthy individuals. Antibodies play an important role in the body damage associated with lupus, and the researchers suggest that this diagnostic antibody response highlights the critical role R. blautia gnavus plays in the autoimmune disease.
Using an antibody biomarker test to detect the newly identified R. blautia gnavus strain-related lipoglycan could potentially aid in the early diagnosis of Lupus nephritis, leading to improved decision making in therapy and targeted treatment of pathobiontic strains.
The researchers believe that understanding the disease’s biological pathways is key to developing new treatments that prevent or treat lupus attacks. In particular, treatments for lupus nephritis could potentially reduce the use of immune-suppressing drugs in favor of less toxic antibacterials, probiotics or nutritional regimens that prevent imbalances such as ruminococcal blooms in the gut microbiome. Previous research by Silverman’s team showed that R. blautia gnavus blooms weaken the intestinal wall barrier, leading to bacterial leaks that trigger inflammatory and overactive immune responses.
The small sample size is a limitation of the single-center observational pilot study. However, the researchers plan to expand their research to include more patients from other medical centers and conduct further experiments with mouse models of lupus. These experiments will investigate how R. blautia gnavus colonization causes lupus and whether it accelerates or influences flare-ups and inflammation in lupus-like mouse models. In addition, the team plans to experiment with different lipoglycan molecules from different R. blautia gnavus strains to determine whether specific structural components are the main triggers for inflammation or whether other lipoglycans trigger immune responses associated with lupus or other intestinal diseases such as gallbladder disease. Crohn’s.