Volume 106, Issue 7, Pages 1778-1786

Authors:

Jane Alrø Bøtkjær, M.Sc., Tanni Borgbo, Ph.D., Søren Kløverpris, Ph.D., Pernille Rimmer Noer, M.Sc., Claus Oxvig, Ph.D., Claus Yding Andersen, D.M.Sc.

Abstract:

Objective

To reveal a possible relationship between two single nucleotide polymorphisms (SNPs) in PAPP-A—1224 (rs7020782) and 327 (rs12375498)—and the level and activity of PAPP-A in follicular fluid (FF) of human small antral follicles, and to analyze the intrafollicular hormone levels.

Design

Laboratory investigation.

Setting

University hospital.

Patient(s)

Fifty volunteer women who contributed a total of 210 samples of FF from normal small antral follicles.

Intervention(s)

Genotyping and measurement of antigen levels of steroids, PAPP-A, stanniocalcin-2 (STC2), and antimüllerian hormone (AMH) plus activity of PAPP-A toward insulin-like growth factor binding protein 4 (IGFBP-4).

Main Outcome Measure(s)

Measurement of PAPP-A levels and hormones with enzyme-linked immunosorbent assay (ELISA) and PAPP-A activity toward radiolabeled IGFBP-4.

Result(s)

Women homozygous for the minor C allele of the 1224 SNP showed a statistically significantly lower level of PAPP-A protein and activity in FF compared with women carrying the major A allele. These women also displayed nonsignificant reduced levels of estradiol and increased levels of AMH and androgen. A statistically significant correlation between FF levels of PAPP-A activity and the molar ratio of PAPP-A/STC2 was obtained. The 327 SNP did not show statistically significant associations.

Conclusion(s)

This study presents a statistically significant effect of the 1224 SNP on the level and activity of PAPP-A in human follicles, suggesting that the FF level of bioactive insulin-like growth factor depends on the genotype. We observed STC2 to be an important regulator of PAPP-A in human FF. The 1224 SNP has previously been associated with recurrent pregnancy loss, so further evaluation of an underlying mechanism including aberrant control of insulin-like growth factor activity is warranted.

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