Identification of PCSK9 as a novel serum biomarker for the prenatal diagnosis of neural tube defects using iTRAQ quantitative proteomics.

To identify candidate serum molecule biomarkers for the non-invasive early prenatal diagnosis of neural tube defects (NTDs), we employed an iTRAQ-based quantitative proteomic approach to analyze the proteomic changes in serum samples from embryonic day (E) 11 and E13 pregnant rats with spina bifida aperta (SBA) induced by all-trans retinoic acid. Among the 390 proteins identified, 40 proteins at E11 and 26 proteins at E13 displayed significant differential expression in the SBA groups. We confirmed 5 candidate proteins by ELISA. We observed the space-time expression changes of proprotein convertase subtilisin/kexin type 9 (PCSK9) at different stages of fetal development, including a marked decrease in the sera of NTD pregnancies and gradual increase in the sera of normal pregnancies with embryonic development. PCSK9 demonstrated the diagnostic efficacy of potential NTD biomarkers [with an area under the receiver operating characteristic curve of 0.763, 95% CI: 065-0.88]. Additionally, PCSK9 expression in the spinal cords and placentas of SBA rat fetuses was markedly decreased. PCSK9 could serve as a novel molecular biomarker for the non-invasive prenatal screening of NTDs and may be involved in the pathogenesis of NTDs at critical periods of fetal development.

Serological differences in folate/vitamin B12 in pregnancies affected by neural tube defects.

BACKGROUND: Laboratory evidence is presented of significant associations between reduced maternal serum folate and vitamin B12 levels and neural tube birth defects (NTD) compared to referents. METHODS: This was an incident case-control study. Cases of neural tube defects (including anencephaly and open spina bifida) diagnosed in residents within 100 miles of the US-Mexico border from January 1993 to October 2000 were eligible. Most cases were diagnosed in utero upon visits to clinics, obstetrical or genetic expert offices. Cases identified upon hospital admission or at delivery were also eligible. Cases identified after discharge were not. Controls were matched on geographic region, maternal age, race/ethnicity, gestational age, and type of health insurance (including none). RESULTS: Three hundred eighty-two border area residents (107 cases and 275 individually matched controls) provided biological specimens. Median folate concentrations for case mothers were 36% lower than controls (9.8 ng/mL vs. 15 ng/mL). Maternal serum folate concentrations in quartiles above 9.5 ng/mL indicated significantly reduced risk (OR = 0.4, OR = 0.3, and OR = 0.2). Likewise, the risk for NTD decreased (OR = 0.4, OR = 0.3, and OR = 0.2) in quartiles of sera B12 concentrations above 246 pg/mL. CONCLUSIONS: Physician attention is invited to significantly lower concentrations of serum folate and vitamin B12 in women with NTD-affected pregnancies. This study assayed sera samples from women while still pregnant or immediately after delivery. The confounding effect of reduced folate and B12 levels with other biological and chemical exposures will be addressed in subsequent communications.

GDNF plasma levels in spina bifida: correlation with severity of spinal damage and motor function.

Glial-derived neurotrophic factor (GDNF) is one of several powerful survival factors for spinal motoneurons that play a key role in sprouting, synaptic plasticity, and reorganization after spinal cord damage. The aim of this study was to investigate the expression of GDNF in plasma of children with spina bifida (SB) and to determine its correlation with both the severity of spinal cord damage and the motor function of these patients. To measure the GDNF expression, we collected plasma samples from 152 children with SB and in 149 matched controls. Endogenous GDNF levels were quantified using a two-site immuno-enzymatic assay. The statistical analysis was performed using the Mann-Whitney two-tailed two-sample test. In children with SB the mean levels of GDNF (131.2 +/- 69.6 pg/mL) were significantly higher (p < 0.001) with respect to the mean levels of the control group (102.7 +/- 6.8 pg/mL). Moreover, in open SB, the GDNF levels (139.2 +/- 81.1 pg/mL) were significantly higher (p < 0.05) with respect to closed SB (117.2 +/- 41.3 pg/mL). In terms of the motor function of patients, we found that in children with poorer motor function, the GDNF levels (134.5 +/- 67.4 pg/mL) were higher, but not statistically significant (p < 0.1), than in patients with better motor outcome (122.3 +/- 72.2 pg/mL). Our study demonstrates GDNF over-expression in children with SB. This upregulation is significantly associated with the severity of spinal cord damage in SB patients and appears to correlate with poor motor function of children, representing an important biochemical marker of the severity of spine injury.

[Noninvasive serum test for prenatal detection of Down syndrome, other chromosome abnormalities and open neural tube defects--a prospective study]. / Nichtinvasiver Serum-Test (NIS) zur pränatalen Erfassung von Morbus Down, anderen chromosomalen Anomalien und offenen Neuralrohrdefekten--Eine prospektive Studie.

Between September 1st 1990 and Juli 31st 1993, 5071 pregnant women were screened prospectively by the "triple-test", including maternal serum alpha-fetoprotein, human chorionic gonadotropin and unconjugated oestriol in order to detect chromosomal anomalies and open neural tube defects. The serum samples were collected in collaboration with the obstetricians of the region of West-Mecklenburg and North-West-Brandenburg. Laboratory testing using radioimmunoassays was performed between weeks 15 and 20 of gestation, all serum specimens being investigated in only one institution. The original alpha-software from Wald et al. was the basis for calculating the statistical risk for Down's syndrome. Pregnant women with a high risk for Down's syndrome (cutoff > or = 1:250) were taken care of in a special outpatient clinic including procedures like amniocentesis and fetal blood sampling. Amongst 5071 pregnant women, 21 fetal anomalies were seen. Five cases of Down's syndrome, three of trisomy 18, one trisomy 13, two cases of triploidy and four cases of open neural tube defects, one 46 xy/45 x mosaic karyotype and one case of gastroschisis could be diagnosed correctly. One case of trisomy 21, one case of trisomy 18 and two open neural tube defects showed false negative results. Using the cutoff of 1:250 for prenatal detection of Down's syndrome and performing ultrasound routinely to determine gestational age, the sensitivity of the "triple-test" was 83.33% having a specificity of 92.68%. The predictive value of a positive test for prenatal diagnosis of Down's syndrome was 1.33%.(ABSTRACT TRUNCATED AT 250 WORDS)