Caffeine, selected metabolic gene variants, and risk for neural tube defects

Exome sequencing of family trios from the National Birth Defects Prevention Study: Tapping into a rich resource of genetic and environmental data

BACKGROUND

The National Birth Defects Prevention Study (NBDPS) is a multisite, population-based, case-control study of genetic and nongenetic risk factors for major structural birth defects. Eligible women had a pregnancy affected by a birth defect or a liveborn child without a birth defect between 1997 and 2011. They were invited to complete a telephone interview to collect pregnancy exposure data and were mailed buccal cell collection kits to collect specimens from themselves, their child (if living), and their child's father. Over 23,000 families representing more than 30 major structural birth defects provided DNA specimens.

METHODS

To evaluate their utility for exome sequencing (ES), specimens from 20 children with colonic atresia were studied. Evaluations were conducted on specimens collected using cytobrushes stored and transported in open versus closed packaging, on native genomic DNA (gDNA) versus whole genome amplified (WGA) products and on a library preparation protocol adapted to low amounts of DNA.

RESULTS

The DNA extracted from brushes in open packaging yielded higher quality sequence data than DNA from brushes in closed packaging. Quality metrics of sequenced gDNA were consistently higher than metrics from corresponding WGA products and were consistently high when using a low input protocol.

CONCLUSIONS

This proof-of-principle study established conditions under which ES can be applied to NBDPS specimens. Successful sequencing of exomes from well-characterized NBDPS families indicated that this unique collection can be used to investigate the roles of genetic variation and gene-environment interaction effects in birth defect etiologies, providing a valuable resource for birth defect researchers.

Interaction between maternal caffeine intake during pregnancy and CYP1A2 C164A polymorphism affects infant birth size in the Hokkaido study

BackgroundCaffeine, 1,3,7-trimethylxanthine, is widely consumed by women of reproductive age. Although caffeine has been proposed to inhibit fetal growth, previous studies on the effects of caffeine on infant birth size have yielded inconsistent findings. This inconsistency may result from failure to account for individual differences in caffeine metabolism related to polymorphisms in the gene for CYP1A2, the major caffeine-metabolizing enzyme.MethodsFive hundred fourteen Japanese women participated in a prospective cohort study in Sapporo, Japan, from 2002 to 2005, and 476 mother-child pairs were included for final analysis.ResultsCaffeine intake was not significantly associated with mean infant birth size. When caffeine intake and CYP1A2 C164A genotype were considered together, women with the AA genotype and caffeine intake of ≥300 mg per day had a mean reduction in infant birth head circumference of 0.8 cm relative to the reference group after adjusting for confounding factors. In a subgroup analysis, only nonsmokers with the AA genotype and caffeine intake of ≥300 mg per day had infants with decreased birth weight (mean reduction, 277 g) and birth head circumference (mean reduction, 1.0 cm).ConclusionNonsmokers who rapidly metabolize caffeine may be at increased risk for having infants with decreased birth size when consuming ≥300 mg of caffeine per day.

Intake of Caffeinated Soft Drinks before and during Pregnancy, but Not Total Caffeine Intake, Is Associated with Increased Cerebral Palsy Risk in the Norwegian Mother and Child Cohort Study

BACKGROUND

Postnatal administration of caffeine may reduce the risk of cerebral palsy (CP) in vulnerable low-birth-weight neonates. The effect of antenatal caffeine exposure remains unknown.

OBJECTIVE

We investigated the association of intake of caffeine by pregnant women and risk of CP in their children.

METHODS

The study was based on The Norwegian Mother and Child Cohort Study, comprising >100,000 live-born children, of whom 222 were subsequently diagnosed with CP. Mothers reported their caffeine consumption in questionnaires completed around pregnancy week 17 (102,986 mother-child pairs), week 22 (87,987 mother-child pairs), and week 30 (94,372 mother-child pairs). At week 17, participants were asked about present and prepregnancy consumption. We used Cox regression models to estimate associations between exposure [daily servings (1 serving = 125 mL) of caffeinated coffee, tea, and soft drinks and total caffeine consumption] and CP in children, with nonconsumers as the reference group. Models included adjustment for maternal age and education, medically assisted reproduction, and smoking, and for each source of caffeine, adjustments were made for the other sources.

RESULTS

Total daily caffeine intake before and during pregnancy was not associated with CP risk. High consumption (≥6 servings/d) of caffeinated soft drinks before pregnancy was associated with an increased CP risk (HR: 1.9; 95% CI: 1.2, 3.1), and children of women consuming 3-5 daily servings of caffeinated soft drinks during pregnancy weeks 13-30 also had an increased CP risk (HR: 1.7; 95% CI: 1.1, 2.8). A mean daily consumption of 51-100 mg caffeine from soft drinks during the first half of pregnancy was associated with a 1.9-fold increased risk of CP in children (HR: 1.9; 95% CI: 1.1, 3.6).

CONCLUSIONS

Maternal total daily caffeine consumption before and during pregnancy was not associated with CP risk in children. The observed increased risk with caffeinated soft drinks warrants further investigation.

Pregnancy and pharmacogenomics in the context of drug metabolism and response

It is well-known that profound physiological and biochemical changes occur throughout the course of pregnancy. At the same time, the role of pharmacogenomics in modulating the metabolism and response profile to numerous medications has been elucidated. Yet, the clinical impact of pharmacogenomics during pregnancy is less well understood. We present an overview of factors modulating the pharmacokinetics and pharmacodynamics of medications throughout the time span of pregnancy while providing insights on how pharmacogenomics may contribute to interindividual variability in drug metabolism and response amongst pregnant women.

Exploring the caffeine-induced teratogenicity on neurodevelopment using early chick embryo

Caffeine consumption is worldwide. It has been part of our diet for many centuries; indwelled in our foods, drinks, and medicines. It is often perceived as a "legal drug", and though it is known to have detrimental effects on our health, more specifically, disrupt the normal fetal development following excessive maternal intake, much ambiguity still surrounds the precise mechanisms and consequences of caffeine-induced toxicity. Here, we employed early chick embryos as a developmental model to assess the effects of caffeine on the development of the fetal nervous system. We found that administration of caffeine led to defective neural tube closures and expression of several abnormal morphological phenotypes, which included thickening of the cephalic mesenchymal tissues and scattering of somites. Immunocytochemistry of caffeine-treated embryos using neural crest cell markers also demonstrated uncharacteristic features; HNK1 labeled migratory crest cells exhibited an incontinuous dorsal-ventral migration trajectory, though Pax7 positive cells of the caffeine-treated groups were comparatively similar to the control. Furthermore, the number of neurons expressing neurofilament and the degree of neuronal branching were both significantly reduced following caffeine administration. The extent of these effects was dose-dependent. In conclusion, caffeine exposure can result in malformations of the neural tube and induce other teratogenic effects on neurodevelopment, although the exact mechanism of these effects requires further investigation.

Digitization of clinical and epidemiological data from the Kyoto Collection of Human Embryos: maternal risk factors and embryonic malformations

Understanding the causes of congenital anomalies is of prime importance to develop management and/or prevention strategies. It is widely accepted that the occurrence of congenital malformations in fetuses and neonates is heavily correlated with maternal genetic makeup and lifestyle. However, very few epidemiologic analyses have been conducted on the embryonic developmental period because of the rarity of data available. Instigated in 1961, the Kyoto Collection of Human Embryos comprises approximately 45,000 specimens of embryos and fetuses. The collection's most unique feature is that most specimens were added to the collection along with epidemiologic information on the respective mothers. This is the first report on the digitization of data from the collection. A total of 22,262 embryonic specimens were selected on the basis of data integrity. Data related to the embryos were then classified according to the following criteria: developmental stage, sampling period, geographical area, maternal determinant, and external malformation. Results indicate that 7.8% of the embryos exhibit external anomalies and 92.2% are without anomalies. The three most common anomalies were nuchal bleb, holoprosencephaly and spina bifida. A special emphasis was placed on the potential association between maternal determinants and embryonic external anomalies, allowing for statistical analyses. The present study provides further evidence that this collection represents a unique source of information to conduct epidemiological analyses, not only to further the understanding of congenital anomalies but also to help establish preventive health guidelines for pregnant women.

Caffeine increases tear volume depending on polymorphisms within the adenosine A2a receptor gene and cytochrome P450 1A2

PURPOSE

The primary aim of the present study was to examine the effect of caffeine on tear volume. The secondary aim was to investigate the relation between caffeine-induced changes in tear volume and polymorphisms in ADORA2A and CYP1A2.

DESIGN

Double-masked, placebo-controlled, crossover study.

PARTICIPANTS

Seventy-eight healthy volunteers were recruited for the study.

METHODS

Subjects participated in 2 sessions in which they received capsules containing either placebo or caffeine. The caffeine capsules were given to the subjects to keep the caffeine volume per body weight within 5 to 7 mg/kg. After caffeine intake, tear meniscus height (TMH) was measured. Subjects provided a blood sample for genotyping.

MAIN OUTCOME MEASURES

Tear meniscus height, single nucleotide polymorphism.

RESULTS

The tear volume increased after caffeine consumption. The net increase in TMH was 0.08 mm (95% confidence interval, 0.05-0.10) greater when participants were given caffeine than when given placebo (P<0.0001). In ADORA2A, the difference in the net increase in TMH for participants who were heterozygous at rs5751876 and rs2298383 was 0.07 mm (P = 0.001) and who were minor homozygous was 0.08 mm (P = 0.007). In CYP1A2, the net increase in TMH for participants who were minor homozygous at rs2472304 was lower than for those who were major homozygous; the difference was 0.06 mm (P = 0.039).

CONCLUSIONS

Caffeine intake increases tear volume and polymorphisms within ADORA2A, and CYP1A2 is associated with the tear increase after caffeine intake. Genetic polymorphisms had a significant effect on tear meniscus that was of limited clinical significance.