Kidney transplantation is the best treatment option for loss of kidney function. Since there are not enough donors available for the large number of patients with kidney disease, it is very important to maintain optimal organ function after transplantation. Understanding the molecular processes in the kidney after transplantation is crucial for this. However, studies on cell biology in transplantation are only possible to a limited extent. Urine is an optimal biomaterial that is easily available for scientific characterization and diagnosis of kidney diseases but due to lack of suitable methods, it has been insufficiently used so far. Markers (e.g. in urine), which allow the prediction of renal function after transplantation, are lacking. The current gold standard are kidney biopsies, but these - as an invasive procedure – come with potential risks.
An interdisciplinary team of scientists working in the field of nephrology, the Cluster of Excellence for Aging Research CECAD, the Center for Molecular Medicine Cologne (CMMC) and the Transplantation Medicine Department of the University Hospital of Cologne have now succeeded in making significant progress in this area. With the help of modern techniques (mass spectrometry), the protein composition of small urinary extracellular vesicles (suEVs)‘, which are produced by all cells of the kidney and excreted in the urine, was examined. For the first time, two cohorts of 22 kidney donors and 22 kidney recipients each have now been tested for suEVs in the context of living donor kidneytransplantation.
The result: a unique atlas of the composition of suEVs, which is now available online. This atlas maps the temporal pattern of the suEV protein signature and the associated cellular processes involved in both early response and longer-term graft adaptation. In addition, these analyses identified a possible biomarker that could provide early information on kidney allograft outcome. A validation in a larger cohort is pending.
'Importantly, the data obtained are not only an excellent basis for a better understanding of the adaptation of the transplant, but also a source of biomarkers for predicting renal function after transplantation,‘ reports study leader Prof. Roman-Ulrich Müller, Clinic II for Internal Medicine.
The study was recently published in the renowned Journal of Extracellular Vesicles: onlinelibrary.wiley.com/doi/10.1002/jev2.12026