The concentrations of osteocalcin and degradation products of type I collagen in pregnant women with pre-eclampsia

Pregnancy history, coronary artery calcification and bone mineral density in menopausal women

OBJECTIVE

This study examined relationships, by pregnancy histories, between bone mineral density (BMD) and coronary artery calcification (CAC) in postmenopausal women.

METHODS

Forty women identified from their medical record as having pre-eclampsia (PE) were age/parity-matched with 40 women having a normotensive pregnancy (NP). Vertebral (T4-9) BMD and CAC were assessed by quantitative computed tomography in 73 (37 with PE and 36 with NP) of the 80 women. Analyses included linear regression using generalized estimating equations.

RESULTS

Women averaged 59 years of age and 35 years from the index pregnancy. There were no significant differences in cortical, trabecular or central BMD between groups. CAC was significantly greater in the PE group (p = 0.026). In multivariable analysis, CAC was positively associated with cortical BMD (p = 0.001) and negatively associated with central BMD (p = 0.036). There was a borderline difference in the association between CAC and central BMD by pregnancy history (interaction, p = 0.057).

CONCLUSIONS

Although CAC was greater in women with a history of PE, vertebral BMD did not differ between groups. However, both cortical and central BMD were associated with CAC. The central BMD association was marginally different by pregnancy history, suggesting perhaps differences in underlying mechanisms of soft tissue calcification.

Maternal circulating osteoprotegerin and soluble RANKL in pre-eclamptic women

OBJECTIVE

To evaluate alterations in the concentrations of osteoprotegerin (OPG), RANKL and the OPG/RANKL ratio in pre-eclamptic women during the puerperium.

STUDY DESIGN

This cross-sectional study was performed in the maternity ward of Aretaieio Hospital in Athens, Greece. Fifteen pregnant women with severe pre-eclampsia and 15 matched controls with premature rupture of the membranes were recruited. Fasting blood samples were obtained antepartum, immediately after diagnosing pre-eclampsia (median: 32nd gestational week), and during the 3rd-6th day postpartum, to estimate levels of circulating OPG and RANKL as well as the OPG/RANKL ratio. The anthropometric parameters evaluated included body mass index and blood pressure.

RESULTS

Mean circulating OPG levels decreased significantly in both groups in the postpartum period (controls: 43.7 ± 19.1 ng/ml vs 22.9 ± 9.1 ng/ml, p = 0.008; pre-eclamptic group: 72.3 ± 49.9 vs 49.7 ± 40.9 ng/ml, p = 0.002). The antepartum OPG/RANKL ratio was elevated in hypertensive pregnancies (2.41 ± 1.72) compared to normotensive pregnancies (1.45 ± 0.63), but the difference did not reach statistical significance (p = 0.1). The OPG/RANKL ratio decreased in the control group (0.76 ± 0.30, NS) following delivery, while it remained unchanged in the pre-eclamptic women (1.63 ± 1.40, p = 0.13). Consequently, the postpartum OPG/RANKL ratio was significantly higher in the pre-eclamptic women compared to control women (1.63 ± 1.40 vs 0.76 ± 0.30, p = 0.01). Levels of RANKL demonstrated no significant alterations during puerperium in both cases.

CONCLUSION

Pregnancies complicated with pre-eclampsia exhibit higher OPG levels and OPG/RANKL ratios, compared to control pregnancies, which might be compatible with lower bone turnover. The significance of this finding with respect to bone metabolism remains to be elucidated in larger studies.

Candidate-gene association study of mothers with pre-eclampsia, and their infants, analyzing 775 SNPs in 190 genes

Pre-eclampsia (PE) affects 5-7% of pregnancies in the US, and is a leading cause of maternal death and perinatal morbidity and mortality worldwide. To identify genes with a role in PE, we conducted a large-scale association study evaluating 775 SNPs in 190 candidate genes selected for a potential role in obstetrical complications. SNP discovery was performed by DNA sequencing, and genotyping was carried out in a high-throughput facility using the MassARRAY(TM) System. Women with PE (n = 394) and their offspring (n = 324) were compared with control women (n = 602) and their offspring (n = 631) from the same hospital-based population. Haplotypes were estimated for each gene using the EM algorithm, and empirical p values were obtained for a logistic regression-based score test, adjusted for significant covariates. An interaction model between maternal and offspring genotypes was also evaluated. The most significant findings for association with PE were COL1A1 (p = 0.0011) and IL1A (p = 0.0014) for the maternal genotype, and PLAUR (p = 0.0008) for the offspring genotype. Common candidate genes for PE, including MTHFR and NOS3, were not significantly associated with PE. For the interaction model, SNPs within IGF1 (p = 0.0035) and IL4R (p = 0.0036) gave the most significant results. This study is one of the most comprehensive genetic association studies of PE to date, including an evaluation of offspring genotypes that have rarely been considered in previous studies. Although we did not identify statistically significant evidence of association for any of the candidate loci evaluated here after adjusting for multiple testing using the false discovery rate, additional compelling evidence exists, including multiple SNPs with nominally significant p values in COL1A1 and the IL1A region, and previous reports of association for IL1A, to support continued interest in these genes as candidates for PE. Identification of the genetic regulators of PE may have broader implications, since women with PE are at increased risk of death from cardiovascular diseases later in life.