Open Access Research article

Calcium-deficiency assessment and biomarker identification by an integrated urinary metabonomics analysis

Maoqing Wang1, Xue Yang1, Fan Wang2, Ran Li3, Hua Ning1, Lixin Na1, Yifan Huang1, Yue Song1, Liyan Liu1, Hongzhi Pan1, Qiuju Zhang4, Lijun Fan4, Ying Li1* and Changhao Sun1*

Author Affiliations

1 Department of Nutrition and Food Hygiene, School of Public Health, Harbin Medical University, 157 Baojian Road, Nangang District, Harbin, 150081, P. R. China

2 Department of Epidemiology, School of Public Health, Harbin Medical University, 157 Baojian Road, Nangang District, Harbin, 150081, P. R. China

3 Department of Public Health Surveillance, Harbin Center for Disease Control and Prevention, 30 Weixing Road, Daowai District, 150056, Harbin, P. R. China

4 Department of Epidemiology and Biostatistics, School of Public Health, Harbin Medical University, 157 Baojian Road, Nangang District, Harbin, 150081, P. R. China

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BMC Medicine 2013, 11:86  doi:10.1186/1741-7015-11-86

Published: 28 March 2013

Additional files

Additional file 1:

Ingredients of diet for the rats in animal experiments.

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Additional file 2:

Results of the calcium metabolic-balance study between the normal-calcium group (NCG) and the low-calcium group (LCG). (A) urine calcium excretion; (B) fecal calcium excretion; (C) calcium intake; (D) calcium retention; (E) apparent absorptivity of calcium.

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Additional file 3:

Two-dimensional principal component analysis (PCA) score plots of urine samples (circle) and quality control (QC) samples (red cross) at weeks 1 to 12 in electrospray ionization (ESI) negative ion mode. Comp, component; t[1], component 1; t[2], component 2.

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Additional file 4:

Permutation test result of the partial least-squares discriminant analysis (PLS-DA) model. The R2Y value represents the goodness of fit of the model, and the Q2 value represents the predictability of the models.

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Additional file 5:

List of discriminating variables between the low-calcium group and normal-calcium group in animal experiment I. RT, retention time.

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Additional file 6:

Urinary metabolic-profiling analysis of experiment II (repeated low-calcium diet experiment). (A) Principal component analysis (PCA) score plots of the low-calcium group (LCG; black triangles) and normal-calcium group (NCG; red circles) rats. (n = 24, week 1 to 12). Each data point represents one subject. (B) Partial least-squares discriminant analysis (PLS-DA) score plot between LCG (black triangles) and NCG (red circles). (n = 24, week 1 to 12). Each data point represents one subject. (C) Permutation test result of PLS-DA model. The R2Y value represents the goodness of fit of the model, and the Q2 value represents the predictability of the models. (D) Batch PLS score plot of urine samples mapped against time (n = 24, week 1 to 12). Dashed horizontal lines show two and three standard deviations for the dataset. LCG rats are shown as black lines and NCG rats as red lines. (E) PCA scores plots of LCG (black squares) and NCG (red triangles) rats. (A-C) Week 2, n = 24 (for two components R2Y = 48.8%, Q2 = 20.7%); week 4, n = 24 (for three components R2Y = 55.1%, Q2 = 26.4%) and week 9, n = 24 (for three components R2Y = 59.1%, Q2 = 28.7%). Each data point represents one subject. (F) Metabolic trajectory scores plots by PCA model derived from the urine of LCG rats (n = 12) from weeks 1 to 12. Black triangle: weeks 1 to 3; red star: weeks 4 to 8; blue circle: weeks 9 to 12. Comp, component. t[1], component 1; t[2], component 2.

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Additional file 7:

List of discriminating variables between the low-calcium diet group and normal-calcium diet group in animal experiment II (repeated low-calcium diet experiment). RT, retnation time.

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Additional file 8:

Detailed identifying experiments using the quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF MS/MS) and authentic standards to elucidate the elemental composition of cAMP.

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Additional file 9:

Identification data of eight biomarkers.

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