title: Protease profiling of different biofluids in type 1 diabetes mellitus.
abstract: OBJECTIVE
  We aimed to disclose the proteolytic events underlying type 1 diabetes and related complication through protease profiling in the bodily fluids serum, urine and saliva.
  
  
  METHODS
  Zymography followed by LC-MS/MS was performed for protease identification and quantitative comparison of proteolytic activity between healthy, type 1 diabetic patients with no complications and with retinopathy and nephropathy. Western blotting was also accomplished for MMP-9 and MMP-2 identification and expression analysis.
  
  
  RESULTS
  Only MMP-2 and MMP-9 were observed in serum with significantly increased levels and activity observed in diabetic patients. In urine and saliva other proteases besides MMPs were identified by MS and presented disease-dependent activity variations. Among these are complex MMP-9/Neutrophil gelatinase-associated lipocalin, aminopeptidase N, azurocidin and kallikrein 1 with more activity noticed in type 1 diabetes patients with nephropathy and/or retinopathy.
  
  
  CONCLUSIONS
  Our data highlight the usefulness of urine and saliva for the monitoring of type-1 diabetes-related proteolytic events, where aminopeptidase N, azurocidin and kallikrein 1 appear as promising screening targets for type 1 diabetes-related complications.
authors.affiliation: QOPNA, Mass Spectrometry Center, Department of Chemistry, University of Aveiro, Aveiro, Portugal.
authors.forename: Armando
authors.initials: A
authors.lastname: Caseiro
authors.forename: Rita
authors.initials: R
authors.lastname: Ferreira
authors.forename: Cláudio
authors.initials: C
authors.lastname: Quintaneiro
authors.forename: Amélia
authors.initials: A
authors.lastname: Pereira
authors.forename: Rosário
authors.initials: R
authors.lastname: Marinheiro
authors.forename: Rui
authors.initials: R
authors.lastname: Vitorino
authors.forename: Francisco
authors.initials: F
authors.lastname: Amado
mesh_terms: D015153:Blotting, Western; D001826:Body Fluids / Q000201:enzymology*; D016022:Case-Control Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000201:enzymology* / Q000652:urine; D003928:Diabetic Nephropathies; D003930:Diabetic Retinopathy / Q000097:blood / Q000201:enzymology / Q000652:urine; D006801:Humans; D013058:Mass Spectrometry; D020778:Matrix Metalloproteinase 2 / Q000652:urine; D020780:Matrix Metalloproteinase 9 / Q000652:urine; D010447:Peptide Hydrolases / Q000097:blood / Q000378:metabolism* / Q000652:urine; D059748:Proteolysis; D040901:Proteomics; D012463:Saliva / Q000201:enzymology
chemical_list: D010447:Peptide Hydrolases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9