Affiliation: | 1. Instituto de Investigación Biomédica de Salamanca (IBSAL)-Instituto de Estudios de Ciencias de la Salud de Castilla y León (IECSCYL), Salamanca, Spain
Departamento de Fisiología y Farmacología, Universidad de Salamanca, Salamanca, Spain
Instituto Reina Sofía de Investigación Nefrológica, Fundación Iñigo Álvarez de Toledo, Madrid, Spain
Red Nacional de Investigaciones Renales (RedinRen), Instituto de Salud Carlos III, Madrid, Spain;2. Instituto de Investigación Biomédica de Salamanca (IBSAL)-Instituto de Estudios de Ciencias de la Salud de Castilla y León (IECSCYL), Salamanca, Spain;3. Instituto de Investigación Biomédica de Salamanca (IBSAL)-Instituto de Estudios de Ciencias de la Salud de Castilla y León (IECSCYL), Salamanca, Spain
Departamento de Fisiología y Farmacología, Universidad de Salamanca, Salamanca, Spain;4. Instituto de Investigación Biomédica de Salamanca (IBSAL)-Instituto de Estudios de Ciencias de la Salud de Castilla y León (IECSCYL), Salamanca, Spain
Departamento de Fisiología y Farmacología, Universidad de Salamanca, Salamanca, Spain
Instituto Reina Sofía de Investigación Nefrológica, Fundación Iñigo Álvarez de Toledo, Madrid, Spain
Red Nacional de Investigaciones Renales (RedinRen), Instituto de Salud Carlos III, Madrid, Spain
Correspondence: Dr. Francisco J. López-Hernández, Instituto de Investigación Biomédica de Salamanca (IBSAL-IECSCYL), Edificio Departamental, Lab. S-20, Campus Miguel de Unamuno, 37007 Salamanca, Spain E-mail: flopezher@usal.es
Fax: +34 923 294 669 |
Abstract: | Urinary differential proteomics is used to study renal pathophysiological mechanisms, find novel markers of biological processes and renal diseases, and stratify patients according to proteomic profiles. The proteomic procedure determines the pathophysiological meaning and clinical relevance of results. Urine samples for differential proteomic studies are usually normalized by protein content, regardless of its pathophysiological characteristics. In the field of nephrology, this approach translates into the comparison of a different fraction of the total daily urine output between proteinuric and nonproteinuric samples. Accordingly, alterations in the level of specific proteins found by this method reflect the relative presence of individual proteins in the urine; but they do not necessarily show alterations in their daily excretion, which is a key parameter for the understanding of the pathophysiological meaning of urinary components. For renal pathophysiology studies and clinical biomarker identification or determination, an alternative proteomic concept providing complementary information is based on sample normalization by daily urine output, which directly informs on changes in the daily excretion of individual proteins. This is clinically important because daily excretion (rather than absolute or relative concentration) is the only self-normalized way to evaluate the real meaning of urinary parameters, which is also independent of urine concentration. |