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Kidney Week

Abstract: TH-PO849

KITGAG: A New Method for Urine and Liquid Biopsy Diagnostics: From Proteoglycan Urinary Fingerprint to Extracellular Like Vesicles (EVLs) Isolation

Session Information

Category: Genetic Diseases of the Kidneys

  • 1001 Genetic Diseases of the Kidneys: Cystic

Authors

  • Vizoso, Marta, Health Research Institute of Santiago de Compostela (IDIS)., Santiago de Compostela, Spain
  • Alvarez, Victor, Health Research Institute of Santiago de Compostela (IDIS)., Santiago de Compostela, Spain
  • Lamas-Gonzalez, Olaya, Health Research Institute of Santiago de Compostela (IDIS)., Santiago de Compostela, Spain
  • Bravo, Susana, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
  • Colon, Cristobal, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
  • Garcia-Gonzalez, Miguel A., Health Research Institute of Santiago de Compostela (IDIS)., Santiago de Compostela, Spain
Background

Glycosaminoglycans (GAG) are large polysaccharides formed by repeated sequences of disaccharides. These molecules are secreted and interact through glycosidic bonds with other molecules, such as proteins and lipids, forming the cellular matrix. GAGs are also part of the structures that cells use for endocrine or paracrine communication, like extracellular vesicles or exosomes; or interact with different secreted proteins.
Glycosylation status of secreted glycoproteins/lipids can be altered in different pathologies, as cancer or kidney diseases.
Current techniques are not able to predict the evolution of kidney diseases. So there is a need of a new methodology that can be used as an indicator of early phases of the disease or prognosis of their evolution.
A new method (KITGAG) has been developed for the separation of free GAGs and the fraction bound to them: based on "Dimethylmethylene blue" (DMB) dye property of specifically binding and precipitating sulfated GAGs in any type of biological sample (urine, serum, tissues...). After the obtaining of this fraction, proteins or lipids profiles can be analyzed by quantitatively or qualitatively methods (proteomics, lipidomics, image techniques...).

Methods

Urine samples have been collected from patients with polycystic kidney disease type I and type II in different stages of disease. Using KITGAG, GAG fraction has been isolated and characterized by different techniques; like Western Blot, mass spectrometry, and electron microscopy.

Results

We have identified markers in the urine from renal patients that appear to be altered in comparison to the healthy population. Likewise, several complexes formed by extracellular vesicles (ELVs), glycoproteins (uromodulin, albumin, IgA or IgG) and GAGs have also been discovered in urine samples, their function may be modulating the dialogue between different nephron segments and it can be altered in renal patients.

Conclusion

Analysis of GAGs fraction in urine samples lead to identification of new prognostic/diagnostic biomarkers of kidney diseases and other different pathologies; or for discovering and monitoring the effect of a therapy. Beside, we have discovered its potential as an isolation method for EVLs for its use in the study of new cellular communication pathways.