Intergenotypic Variation of Endothelial Dysfunction and Inflammatory Markers in Eclampsia

Influence of storage conditions and extraction methods on the quantity and quality of circulating cell-free DNA (ccfDNA): the SPIDIA-DNAplas External Quality Assessment experience

BACKGROUND

Circulating cell-free DNA (ccfDNA) has been confirmed as a useful biomarker in cancer and pre-natal clinical practice. One of the main critical points in using ccfDNA is a lack of standardisation for sample processing methods, storage conditions, procedures for extraction, and quantification that can affect ccfDNA quality and quantity. We report the results obtained from the SPIDIA-DNAplas, one of the EU SPIDIA (Standardisation and improvement of generic pre-analytical tools and procedures for in vitro diagnostics) subprojects based on the implementation of an External Quality Assessment scheme for the evaluation of the influence of the pre-analytical phase on ccfDNA. This is the first reported quality control scheme targeting ccfDNA for pre-analytical phase studies.

METHODS

Fifty-six laboratories throughout Europe were recruited. The participating laboratories received the same plasma sample and extracted ccfDNA by using their own procedures, at defined plasma storage conditions, and sent the isolated ccfDNA to the SPIDIA facility for analyses. Laboratory performance was evaluated by using specific quality parameters such as ccfDNA integrity (by multiplex PCR) and yield (by qPCR).

RESULTS

The analysis of the ccfDNA extracted by the laboratories showed that most of them (53 of 56) were able to recover ccfDNA but only 12.5% recovered non-fragmented ccfDNA. Extraction methods specifically designed for ccfDNA preserved the integrity profile.

CONCLUSIONS

The evidence-based results of the SPIDIA-DNAplas EQA have been proposed as a basis for the development of a Technical Specification by the European Committee for standardisation (CEN).

Associations between nitric oxide synthase 3 gene polymorphisms and preeclampsia risk: a meta-analysis

Previous studies have examined the role of three NOS3 gene polymorphisms [G894T, T-786C, and the variable number of tandem repeats 4b/a (VNTR 4b/a)] in the susceptibility to preeclampsia with inconclusive findings. We therefore conducted an updated meta-analysis by including more studies. The most appropriate genetic model was chosen for each polymorphism by using a well-established method. Pooled results indicated that, compared with the GT + GG genotype, the TT genotype of G894T was associated with an increased risk of preeclampsia (odds ratio (OR) = 1.46; 95% confidence interval (CI) = 1.21–1.77, P < 0.001; I² = 40.2%). The CC genotype of T-786C was also associated with a higher risk of preeclampsia (OR = 1.30; 95% CI = 1.07–1.58, P = 0.034; I² = 46.9%) than the CT + TT genotype. No association was found for VNTR 4b/a. Stratified analysis indicated that the increased risk was evident for high-quality studies both for G894T and T-786C, and for studies conducted among Caucasians and Africans for T-786C. However, the increased risk for T-786C among Africans needs further confirmation due to the high probability of false-positive reports. Our results suggested that G894T and T-786C polymorphisms, but not VNTR 4b/a, were associated with an increased risk of preeclampsia.

Is the serum l-arginine level during early pregnancy a predictor of pregnancy-induced hypertension?

The objective of this study was to determine the concentration of serum l-arginine in healthy pregnant women and infant cord blood and to compare them with those in patients with pregnancy-induced hypertension (PIH). The serum concentration of l-arginine in normal pregnant women at early gestation (n = 186) was determined and analyzed based on maternal factors such as the age, pre-pregnancy body mass index (BMI), smoking and alcohol habits before pregnancy. Similarly, the concentration of cord blood of the newborns (n = 142) was also analyzed. These values were compared with those in the PIH group (n = 21). The potential risk factors for PIH were also estimated. The serum concentration of l-arginine at early gestation in normal pregnant women (88.65 ± 19.96 µM) was not affected by the maternal age and BMI before pregnancy. A lower l-arginine concentration at early gestation (<70 µM) significantly elevated PIH risk [adjusted odds ratio (OR) = 4.26, 95% CI 1.29-14.50]. In addition, either women with large body mass before pregnancy (BMI>25 kg/m(2)) or primipara women also showed a significant association with PIH risk [adjusted OR = 10.55 (2.95-40.68); 5.25 (1.72-19.15), respectively]. In conclusion, a lower l-arginine concentration at early gestation, overweight before pregnancy (BMI>25 kg/m(2)) and primipara could predict to the development of PIH.