A study by ibs.GRANADA identifies new clues in the urinary microbiota to diagnose renal lupus
The study, published in the journal Biomarker Research, analyzes the urinary microbiota of nearly 600 people and identifies two bacterial genes with potential as biomarkers for lupus nephritis.
Researchers from the Granada Institute for Biomedical Research (ibs.GRANADA), in collaboration with the University of Granada, the Andalusian Public Foundation for Progress and Health (FPS), and the University of Almería, have discovered that certain signals present in urine bacteria could help detect kidney damage associated with lupus. These findings suggest the possibility of developing new, simpler, and non-invasive diagnostic strategies for this disease.
Lupus is a complex autoimmune disease in which the body's immune system mistakenly attacks various organs, causing inflammation and, over time, impaired function, including the kidneys. When it affects the kidneys, it is called lupus nephritis, one of the most serious complications and a leading cause of death in these patients. Currently, the diagnosis of this kidney involvement relies on clinical tests that are not always specific and, above all, on performing a kidney biopsy, a highly complex and invasive procedure.
Although urine from healthy individuals has traditionally been considered sterile, recent studies have shown that a small community of bacteria naturally coexists in the bladder. Based on this evidence, the research team studied the urinary microbiota of nearly 600 people, comparing samples from healthy individuals, lupus patients without kidney involvement, and patients with renal lupus. Using advanced genetic sequencing techniques, they identified changes in the composition of these bacteria in those with kidney involvement. Furthermore, using artificial intelligence tools, they detected two bacterial genes with significant potential as biomarkers for renal lupus. Taken together, these findings could lay the groundwork for developing a faster and less invasive diagnostic test in the future.
The study also shows differences in the activity of bacteria present in urine depending on the type of lupus. In patients without kidney involvement, an increase in bacterial amino acid metabolism was observed—that is, in the way these bacteria process certain building blocks of proteins. This increased metabolism is associated with a lower availability of pro-inflammatory amino acids, such as leucine and valine. However, this pattern was not detected in patients with renal lupus, where the higher levels of these amino acids could contribute to maintaining the persistent inflammation of the urinary tract that characterizes this complication.
According to Virginia Pérez Carrasco, a predoctoral researcher in the group E16 – Emerging and Translational Microbiology of the ibs.GRANADA And the study's first author, "identifying biomarkers in urine represents a step towards more personalized medicine in lupus. Our goal is to contribute to the development of tools that allow for earlier diagnosis and more precise monitoring of kidney involvement, reducing the burden of biopsies for patients."
This study was conducted at ibs.GRANADA and the Pfizer-University of Granada-Andalusian Regional Government Center for Genomics and Oncological Research (GENYO) by the group of Dr. José Antonio García Salcedo. The work is part of the international PRECISESADS project and forms part of the doctoral thesis of researcher Virginia Pérez Carrasco.
Bibliographic reference:
Pérez-Carrasco, V., Soriano-Lerma, A., Guzzi, C., García-Martín, ML, Tello, MJ, Linde-Rodríguez, Á., Sánchez-Martín, V., Ortiz-González, M., PRECISESADS Clinical Consortium, Gutiérrez-Fernández, J., Alarcón-Riquelme, ME, Soriano, M., Marañón, C., & García-Salcedo, JA (2025). Identification of urinary bacterial genes as biomarkers for non-invasive diagnosis of renal lupus. Biomarker research, 13(1), 117. https://doi.org/10.1186/s40364-025-00828-5
Contact:
Jose Antonio Garcia Salcedo (joseantonio.garcia@genyo.es). Principal Investigator of ibs.GRANADA, at the Pfizer-University of Granada-Andalusian Regional Government Centre for Genomics and Oncological Research (GENYO).
Virginia Pérez Carrasco (virginia.perez@genyo.es). Predoctoral researcher at ibs.GRANADA, at the Pfizer-University of Granada-Andalusian Regional Government Center for Genomics and Oncological Research (GENYO).
About the group:
El grupo E16 – Emerging and Translational Microbiology The Granada Institute for Biomedical Research (ibs.GRANADA) focuses its activity on the study of microorganisms that pose a growing threat to public health, addressing everything from emerging infections to antimicrobial resistance. Its research combines clinical microbiology, molecular biology, and epidemiology with a distinctly translational approach, meaning it is geared towards translating laboratory findings into clinical practice. This work improves the diagnosis, treatment, and prevention of infectious diseases, contributing to a more effective response to new pathogens and a more rational use of antibiotics. Through close collaboration with hospitals and universities, the group promotes high-impact biomedical research that directly benefits public health.
More information: https://www.ibsgranada.es/grupos-de-investigacion/e16-microbiologia-emergente-y-traslacional/
