Research Article

Mass spectrometric quantification of AcSDKP-NH2 in human plasma and urine and comparison with an immunoassay

  1. Cédric Mesmin1,
  2. Sophie Cholet1,
  3. Anne Blanchard2,3,4,
  4. Yann Chambon2,3,
  5. Michel Azizi2,3,4,
  6. Eric Ezan1,*

Article first published online: 8 DEC 2011

DOI: 10.1002/rcm.5326

Issue

Rapid Communications in Mass Spectrometry

Rapid Communications in Mass Spectrometry

Volume 26, Issue 2, pages 163–172, 30 January 2012

Additional Information

How to Cite

Mesmin, C., Cholet, S., Blanchard, A., Chambon, Y., Azizi, M. and Ezan, E. (2012), Mass spectrometric quantification of AcSDKP-NH2 in human plasma and urine and comparison with an immunoassay. Rapid Commun. Mass Spectrom., 26: 163–172. doi: 10.1002/rcm.5326

Author Information

  1. 1

    CEA, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, laboratoire d'étude du métabolisme des médicaments, Gif-sur-Yvette Cedex, France

  2. 2

    Université Paris Descartes, Paris-Sorbonne Cité, Paris, France

  3. 3

    Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France

  4. 4

    INSERM, Clinical Investigation Center 9201, Paris, France

*E. Ezan, CEA, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, 911191 Gif-sur-Yvette, France.
E-mail: eric.ezan@cea.fr

Publication History

  1. Issue published online: 5 DEC 2011
  2. Article first published online: 8 DEC 2011
  3. Manuscript Accepted: 8 NOV 2011
  4. Manuscript Revised: 7 NOV 2011
  5. Manuscript Received: 5 OCT 2011

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RATIONALE

Precise assessment of renal glomerular filtration rate (GFR) is essential for the early detection of chronic kidney disease. AcSDKP-NH2, an analogue of the endogenous tetrapeptide AcSDKP, is not degraded in vivo and is freely filtered by the kidney and eliminated in urine; for that reason this analogue is an ideal candidate marker for the assessment of GRF after administration to humans. Proof-of-concept demonstration and lack of toxicity in animals have allowed an ongoing clinical study in which AcSDKP-NH2 was administered intravenously at a dose of 100 µg and compared with currently available GFR markers. The use of the AcSDKP analogue in clinical practice requires that this novel marker be associated with an analytical method that combines specificity, robustness and high accuracy. We have developed a liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay and compared it with an existing enzyme immunoassay (EIA) for AcSDKP-NH2.

METHODS

Human urine and plasma samples from the clinical study were analyzed by EIA and LC/MS/MS. Before LC/MS/MS assessment, AcSDKP-NH2 was extracted using mixed-mode cation-exchange solid-phase extraction cartridges. Chromatographic separation was performed by hydrophilic interaction liquid chromatography (HILIC), before analysis with an electrospray ionization triple quadrupole mass spectrometer.

RESULTS

Mass spectrometry, through the use of an internal standard, tailored sample preparation and chromatographic separation, has better intra- and inter-assay precision (accuracies between 95 and 101% with CVs < 8% for LC/MS/MS vs. accuracies between 90 and 115% with CVs <18% for EIA) and allows greater steadiness in intra-subject concentrations during the infusion (4.4% for LC/MS/MS vs. 8.6% for EIA). Moreover, the LC/MS/MS assay circumvents matrix effects observed in certain instances for the EIA and which may reduce its accuracy.

CONCLUSIONS

Although the EIA can provide sufficient information in most subjects, the LC/MS/MS assay associated with this new marker should be the reference method. Copyright © 2011 John Wiley & Sons, Ltd.

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