Measurement by a Novel LC-MS/MS Methodology Reveals Similar Serum Concentrations of Vitamin D-Binding Protein in Blacks and Whites

Overview

Journal Clin Chem

Publisher Oxford University Press

Specialty Biochemistry

Date 2015 Oct 11

PMID 26453697

Citations 72

Authors

Clark M Henderson

Pamela L Lutsey

Jeffrey R Misialek

Thomas J Laha

Elizabeth Selvin

John H Eckfeldt

Andrew N Hoofnagle

Affiliations

Soon will be listed here.

Abstract

Background: Vitamin D deficiency is associated with poor bone health and other adverse health outcomes; however, the associations are greatly attenuated in black vs white individuals. One possible explanation for this attenuation is different concentrations of bioavailable vitamin D metabolites in plasma, which are estimated with equations that include the total concentration of vitamin D binding globulin (VDBG) and haplotype-specific dissociation constants.

Methods: We developed a method to quantify VDBG with LC-MS/MS that could also identify the haplotypes/isoforms of VDBG present. We validated the method according to recent recommendations for publications of biomarker studies. We determined serum VDBG concentrations in samples from the Atherosclerosis Risk in Communities cohort and compared the results with a widely used monoclonal immunoassay.

Results: With 10 μL of serum or plasma, the lower limit of quantification for the assay (<20% CV) was 71 μg/mL. The assay was linear from 62 to 434 μg/mL, with total imprecision of 7.3-9.0% CV at approximately 250 μg/mL. Significant hemolysis interfered with quantification. The identification of isoforms was 97% concordant with genotyping (κ coefficient). Method comparison with immunoassay revealed significant isoform-specific effects in the immunoassay. Mean concentrations (SD) of VDBG by mass spectrometry were similar in whites and blacks [262 (25) vs 266 (35) μg/mL, respectively; P = 0.43].

Conclusions: Validated mass spectrometric methods for the quantification of proteins in human samples can provide additional information beyond immunoassay. Counter to prior observations by immunoassay, VDBG concentrations did not vary by race.

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References

White P, Cooke N . The multifunctional properties and characteristics of vitamin D-binding protein. Trends Endocrinol Metab. 2000; 11(8):320-7. DOI: 10.1016/s1043-2760(00)00317-9. View

Lauridsen A, Vestergaard P, Nexo E . Mean serum concentration of vitamin D-binding protein (Gc globulin) is related to the Gc phenotype in women. Clin Chem. 2001; 47(4):753-6. View

Gomme P, Bertolini J . Therapeutic potential of vitamin D-binding protein. Trends Biotechnol. 2004; 22(7):340-5. DOI: 10.1016/j.tibtech.2004.05.001. View

Bouillon R, Van Baelen H, DE MOOR P . Comparative study of the affinity of the serum vitamin D-binding protein. J Steroid Biochem. 1980; 13(9):1029-34. DOI: 10.1016/0022-4731(80)90133-8. View

Yang F, Brune J, Naylor S, Cupples R, Naberhaus K, BOWMAN B . Human group-specific component (Gc) is a member of the albumin family. Proc Natl Acad Sci U S A. 1985; 82(23):7994-8. PMC: 391428. DOI: 10.1073/pnas.82.23.7994. View

Cooke N, David E . Serum vitamin D-binding protein is a third member of the albumin and alpha fetoprotein gene family. J Clin Invest. 1985; 76(6):2420-4. PMC: 424397. DOI: 10.1172/JCI112256. View

Koszelak S, McPherson A, Bouillon R, Van Baelen H . Crystallization and preliminary X-ray analysis of the vitamin D-binding protein from human serum. J Steroid Biochem. 1985; 23(6A):1077-8. DOI: 10.1016/0022-4731(85)90070-6. View

Kamboh M, Ferrell R . Ethnic variation in vitamin D-binding protein (GC): a review of isoelectric focusing studies in human populations. Hum Genet. 1986; 72(4):281-93. DOI: 10.1007/BF00290950. View

Bikle D, Gee E, Halloran B, Kowalski M, Ryzen E, Haddad J . Assessment of the free fraction of 25-hydroxyvitamin D in serum and its regulation by albumin and the vitamin D-binding protein. J Clin Endocrinol Metab. 1986; 63(4):954-9. DOI: 10.1210/jcem-63-4-954. View

10.

Dunn J . Computer simulation of vitamin D transport. Ann N Y Acad Sci. 1988; 538:69-76. DOI: 10.1111/j.1749-6632.1988.tb48851.x. View

11.

Arnaud J, Constans J . Affinity differences for vitamin D metabolites associated with the genetic isoforms of the human serum carrier protein (DBP). Hum Genet. 1993; 92(2):183-8. DOI: 10.1007/BF00219689. View

12.

Rifai N, Gillette M, Carr S . Protein biomarker discovery and validation: the long and uncertain path to clinical utility. Nat Biotechnol. 2006; 24(8):971-83. DOI: 10.1038/nbt1235. View

13.

Holick M . Vitamin D deficiency. N Engl J Med. 2007; 357(3):266-81. DOI: 10.1056/NEJMra070553. View

14.

Aloia J . African Americans, 25-hydroxyvitamin D, and osteoporosis: a paradox. Am J Clin Nutr. 2008; 88(2):545S-550S. PMC: 2777641. DOI: 10.1093/ajcn/88.2.545S. View

15.

Melamed M, Michos E, Post W, Astor B . 25-hydroxyvitamin D levels and the risk of mortality in the general population. Arch Intern Med. 2008; 168(15):1629-37. PMC: 2677029. DOI: 10.1001/archinte.168.15.1629. View

16.

Borges C, Jarvis J, Oran P, Nelson R . Population studies of Vitamin D Binding Protein microheterogeneity by mass spectrometry lead to characterization of its genotype-dependent O-glycosylation patterns. J Proteome Res. 2008; 7(9):4143-53. DOI: 10.1021/pr8002936. View

17.

Huang L, Li Y, Singleton A, Hardy J, Abecasis G, Rosenberg N . Genotype-imputation accuracy across worldwide human populations. Am J Hum Genet. 2009; 84(2):235-50. PMC: 2668016. DOI: 10.1016/j.ajhg.2009.01.013. View

18.

Hoofnagle A, Wener M . The fundamental flaws of immunoassays and potential solutions using tandem mass spectrometry. J Immunol Methods. 2009; 347(1-2):3-11. PMC: 2720067. DOI: 10.1016/j.jim.2009.06.003. View

19.

MacLean B, Tomazela D, Shulman N, Chambers M, Finney G, Frewen B . Skyline: an open source document editor for creating and analyzing targeted proteomics experiments. Bioinformatics. 2010; 26(7):966-8. PMC: 2844992. DOI: 10.1093/bioinformatics/btq054. View

20.

Musunuru K, Lettre G, Young T, Farlow D, Pirruccello J, Ejebe K . Candidate gene association resource (CARe): design, methods, and proof of concept. Circ Cardiovasc Genet. 2010; 3(3):267-75. PMC: 3048024. DOI: 10.1161/CIRCGENETICS.109.882696. View