title: Current state of the art for enhancing urine biomarker discovery.
abstract: Urine is a highly desirable biospecimen for biomarker analysis because it can be collected recurrently by non-invasive techniques, in relatively large volumes. Urine contains cellular elements, biochemicals, and proteins derived from glomerular filtration of plasma, renal tubule excretion, and urogenital tract secretions that reflect, at a given time point, an individual's metabolic and pathophysiologic state.
  
  
  
  High-resolution mass spectrometry, coupled with state of the art fractionation systems are revealing the plethora of diagnostic/prognostic proteomic information existing within urinary exosomes, glycoproteins, and proteins. Affinity capture pre-processing techniques such as combinatorial peptide ligand libraries and biomarker harvesting hydrogel nanoparticles are enabling measurement/identification of previously undetectable urinary proteins. Expert commentary: Future challenges in the urinary proteomics field include a) defining either single or multiple, universally applicable data normalization methods for comparing results within and between individual patients/data sets, and b) defining expected urinary protein levels in healthy individuals.
authors.affiliation: a Center for Applied Proteomics and Molecular Medicine , George Mason University , Manassas , VA , USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Harpole
authors.affiliation: b Department of Chemistry/Biochemistry , George Mason University , Manassas , VA , USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Davis
authors.affiliation: a Center for Applied Proteomics and Molecular Medicine , George Mason University , Manassas , VA , USA.
authors.forename: Virginia
authors.initials: V
authors.lastname: Espina
mesh_terms: D015415:Biomarkers / Q000032:analysis*; D055354:Exosomes; D006031:Glycosylation; D006801:Humans; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D040901:Proteomics / Q000379:methods*; D016482:Urinalysis / Q000379:methods*; D014556:Urine / Q000737:chemistry*
chemical_list: D015415:Biomarkers
keywords: Biomarker; Lyme Disease; combinatorial peptide ligand libraries; diabetes; glycoprotein; hydrogel nanoparticles; mass spectrometry; protein; proteomics; selected reaction monitoring; urine