1. Volume 85, Issue 1, Pages 103-111 (January 2014)
Identification of a urine metabolomic signature in patients with advanced-stage chronic kidney disease 
Maria Posada-Ayala, Irene Zubiri, Marta Martin-Lorenzo, Aroa Sanz-Maroto, Dolores Molero, Laura Gonzalez-Calero, Beatriz Fernandez-Fernandez, Fernando de la Cuesta, Carlos M. Laborde, Maria G. Barderas, Alberto Ortiz, Fernando Vivanco, Gloria Alvarez- Llamas 
Kidney International 
Volume 85, Issue 1, Pages (January 2014)
DOI: /ki
Copyright © 2014 International Society of Nephrology Terms and Conditions

2. Figure 1
Overview of study design and flow of results. Urine samples in each phase and in each of the two validation studies were obtained from independent patient and control cohorts. The discovery phase was approached by nuclear magnetic resonance (NMR); the validation phase was carried out by Selected Reaction Monitoring (SRM) liquid chromatography-mass spectrometry (LC-MS) and the urine metabolome from 12 new individuals was analyzed by NMR, and grouping in the principal component analysis (PCA) graph was inspected. QQQ, triple quadrupole.
Kidney International  , DOI: ( /ki )
Copyright © 2014 International Society of Nephrology Terms and Conditions

3. Figure 2
Principal component analysis (PCA) and partial least square analysis (PLS) of nuclear magnetic resonance (NMR) data (discovery phase). Black dots: control individuals; gray dots: chronic kidney disease (CKD) patients.
Kidney International  , DOI: ( /ki )
Copyright © 2014 International Society of Nephrology Terms and Conditions

4. Figure 3
Representative 1H nuclear magnetic resonance (NMR) spectra. *Myoinositol, *Threitol, 3Citrate, 4Isobutyrate, *Taurine, 6Homocysteine, 7,*Acetylglutamine, *Serine, *Guanidoacetate, *Dimethylglycine, 11,*α-Phenylacetylglutamine, 12,*Tyrosine, *TMANO, 14,*Hippurate, 15O-Cresylsulfate, 16Creatinine, *Betaine, 18,*Malate, 195-Oxoproline, 20,*Prolibetaine, 21,*Leucine, *Threonine, 23,*Alanine, *Glycine, 25,*Histamine, 26,*Phenylalanine, *Arginine, 28Urea. Metabolites identified in overlapping areas were confirmed by two-dimensional (2D) NMR experiments.
Kidney International  , DOI: ( /ki )
Copyright © 2014 International Society of Nephrology Terms and Conditions

5. Figure 4
Metabolites found significantly altered in chronic kidney disease (CKD) by Selected Reaction Monitoring (SRM; validation stage). Graphs show SRM-corrected areas for healthy individuals (control) and CKD patients. Only significantly different (CKD vs. control) metabolites are shown.
Kidney International  , DOI: ( /ki )
Copyright © 2014 International Society of Nephrology Terms and Conditions

6. Figure 5
Principal component analysis (PCA) showing 1H nuclear magnetic resonance (NMR) data from 12 new individuals (controls and chronic kidney disease (CKD) patients) represented as dots within squares in addition to the 30 individuals analyzed in the discovery phase represented as dots without squares. Black dots: healthy subjects; gray dots: CKD patients.
Kidney International  , DOI: ( /ki )
Copyright © 2014 International Society of Nephrology Terms and Conditions