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

Abstract

BackgroundCalcium deficiency is a global public-health problem. Although the initial stage of calcium deficiency can lead to metabolic alterations or potential pathological changes, calcium deficiency is difficult to diagnose accurately. Moreover, the details of the molecular mechanism of calcium deficiency remain somewhat elusive. To accurately assess and provide appropriate nutritional intervention, we carried out a global analysis of metabolic alterations in response to calcium deficiency.MethodsThe metabolic alterations associated with calcium deficiency were first investigated in a rat model, using urinary metabonomics based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry and multivariate statistical analysis. Correlations between dietary calcium intake and the biomarkers identified from the rat model were further analyzed to confirm the potential application of these biomarkers in humans.ResultsUrinary metabolic-profiling analysis could preliminarily distinguish between calcium-deficient and non-deficient rats after a 2-week low-calcium diet. We established an integrated metabonomics strategy for identifying reliable biomarkers of calcium deficiency using a time-course analysis of discriminating metabolites in a low-calcium diet experiment, repeating the low-calcium diet experiment and performing a calcium-supplement experiment. In total, 27 biomarkers were identified, including glycine, oxoglutaric acid, pyrophosphoric acid, sebacic acid, pseudouridine, indoxyl sulfate, taurine, and phenylacetylglycine. The integrated urinary metabonomics analysis, which combined biomarkers with regular trends of change (types A, B, and C), could accurately assess calcium-deficient rats at different stages and clarify the dynamic pathophysiological changes and molecular mechanism of calcium deficiency in detail. Significant correlations between calcium intake and two biomarkers, pseudouridine (Pearson correlation, r = 0.53, P = 0.0001) and citrate (Pearson correlation, r = -0.43, P = 0.001), were further confirmed in 70 women.ConclusionsTo our knowledge, this is the first report of reliable biomarkers of calcium deficiency, which were identified using an integrated strategy. The identified biomarkers give new insights into the pathophysiological changes and molecular mechanisms of calcium deficiency. The correlations between calcium intake and two of the biomarkers provide a rationale or potential for further assessment and elucidation of the metabolic responses of calcium deficiency in humans.

Zinc deficiency decreases bone mineral density of rat by calmodulin-induced change in calcium metabolism

“…In the second experiment, due to the relatively young age of the rats and a longer feeding period, the low zinc diet affected bone development and decreased femur length. In our previous study, we found that a low calcium diet (12 weeks) decreased rat BMD [28]. However, in the present study, we found that a low zinc diet (four weeks) decreased BMD and femur length of LZG (Figure 2).…”

Vitamin D-Enhanced Duodenal Calcium Transport

“…Up until now, clinicians often use plasma levels of calcium, inorganic phosphate, PTH, 25(OH)D 3 , 1,25(OH) 2 D 3 , and bone turnover markers (e.g., C-telopeptide of type I collagen) to represent body calcium status. Other promising candidates as indicators of calcium deficiency and calcium intake in humans include urinary concentrations of pseudouridine and citrate as revealed by a metabonomics analysis (Wang et al, 2013).…”

Potential serum biomarkers from a metabolomics study of autism

“…This method has been widely used to investigate subtle metabolite alterations in complex mixtures. [29][30][31][32][33] Here, we report a serum metabolomic analysis of a cohort of patients with autism and healthy individuals in the Han Chinese population using ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF MS/MS) to identify metabolites and potential serum biomarkers associated with autism. We validated the potential biomarkers using an independent autism case-control cohort.…”