Evaluation of the reproductive and developmental risks of caffeine

Developmental consequences of fetal exposure to drugs: what we know and what we still must learn

Most drugs of abuse easily cross the placenta and can affect fetal brain development. In utero exposures to drugs thus can have long-lasting implications for brain structure and function. These effects on the developing nervous system, before homeostatic regulatory mechanisms are properly calibrated, often differ from their effects on mature systems. In this review, we describe current knowledge on how alcohol, nicotine, cocaine, amphetamine, Ecstasy, and opiates (among other drugs) produce alterations in neurodevelopmental trajectory. We focus both on animal models and available clinical and imaging data from cross-sectional and longitudinal human studies. Early studies of fetal exposures focused on classic teratological methods that are insufficient for revealing more subtle effects that are nevertheless very behaviorally relevant. Modern mechanistic approaches have informed us greatly as to how to potentially ameliorate the induced deficits in brain formation and function, but conclude that better delineation of sensitive periods, dose-response relationships, and long-term longitudinal studies assessing future risk of offspring to exhibit learning disabilities, mental health disorders, and limited neural adaptations are crucial to limit the societal impact of these exposures.

Effect of Caffeine Chronically Consumed During Pregnancy on Adenosine A1 and A2A Receptors Signaling in Both Maternal and Fetal Heart from Wistar Rats

Background: Caffeine is the most widely consumed psychoactive substance in the world, even during pregnancy. Its stimulatory effects are mainly due to antagonism of adenosine actions by blocking adenosine A₁ and A_2A receptors. Previous studies have shown that caffeine can cross the placenta and therefore modulate these receptors not only in the fetal brain but also in the heart. Methods: In the present work, the effect of caffeine chronically consumed during pregnancy on A₁ and A_2A receptors in Wistar rat heart, from both mothers and their fetuses, were studied using radioligand binding, Western-blotting, and adenylyl cyclase activity assays, as well as reverse transcription polymerase chain reaction. Results: Caffeine did not significantly alter A₁R neither at protein nor at gene expression level in both the maternal and fetal heart. On the contrary, A_2AR significantly decreased in the maternal heart, although mRNA was not affected. Gi and Gs proteins were also preserved. Finally, A₁R-mediated inhibition of adenylyl cyclase activity did not change in the maternal heart, but A_2AR mediated stimulation of this enzymatic activity significantly decreased according to the detected loss of this receptor. Conclusions: Opposite to the downregulation and desensitization of the A₁R/AC pathway previously reported in the brain, these results show that this pathway is not affected in rat heart after caffeine exposure during pregnancy. In addition, A_2AR is downregulated and desensitized in the maternal heart, suggesting a differential modulation of these receptor-mediated pathways by caffeine.

Maternal caffeine intake during pregnancy is associated with risk of low birth weight: a systematic review and dose-response meta-analysis

BACKGROUND

Considerable controversy exists regarding the relation between maternal caffeine intake during pregnancy and risk of low birth weight (birth weight <2,500 g). We aim to assess this association using a systematic review and dose-response meta-analysis of prospective studies.

METHODS

Potential articles were identified by searching MEDLINE and SCOPUS databases through 17 July 2013. Two authors independently extracted information on study design, participant characteristics and estimates of associations. Random-effects models were used to derive the summary relative risks (RRs) and corresponding 95% confidence intervals (CIs). Dose-response relationships were assessed using generalized least-squares trend estimation.

RESULTS

In our meta-analysis, we included 13 prospective studies: 9 with low birth weight as a binary outcome variable (90,747 participants and 6,303 cases) and 6 with birth weight as a continuous outcome variable (10,015 participants; 2 studies reported both types of outcomes). Compared with the reference category with no or very low caffeine intake, the RR (95% CI) of low birth weight was 1.13 (1.06 to 1.21; I 2 0.0%) for low intake (50 to 149 mg/day), 1.38 (1.18 to 1.62; I 2 31.9%) for moderate intake (150 to 349 mg/day), and 1.60 (1.24 to 2.08; I 2 65.8%) for high intake (≥350 mg/day). In the dose-response analysis, each 100-mg/day increment in maternal caffeine intake (around one cup of coffee) was associated with 13% (RR 1.13, 1.06 to 1.21) higher risk of low birth weight. The association persisted in strata defined according to various study characteristics. Moderate (-33 g, 95% CI -63 to -4; I 2 0.3%) and high (-69 g, 95% CI -102 to -35; I 2 0.0%) caffeine intakes were also associated with a significantly lower birth weight as compared with the reference category.

CONCLUSIONS

Higher maternal caffeine intake during pregnancy was associated with a higher risk of delivering low birth weight infants. These findings support recommendations to restrict caffeine intake during pregnancy to low levels.

Counseling women and men regarding exposures to reproductive and developmental toxicants before conception or women during pregnancy

It should be apparent that determining the reproductive risks of an exposure during pregnancy or the cause of a child's congenital malformations is not a simple process. It involves a careful analysis of the medical and scientific literature pertaining to the reproductive toxic effects of exogenous agents in humans and animals, as well as an evaluation of the exposure and the biological plausibility of the concern of an increased risk or a causal connection between the exposure and a child's congenital malformations. It also involves having available a detailed physical examination of the malformed infant or child and a review of the scientific literature pertaining to genetic and environmental causes of the malformations in question. Abridged counseling on the basis of superficial and incomplete analyses is a disservice to the family. Experienced counselors understand that their primary task is to educate the pregnant women or family members concerning the risk of an environmental exposure. The counselor should advise them on the options available, but not on which option to select.

Developmental toxicity assay using high content screening of zebrafish embryos

Typically, time-consuming standard toxicological assays using the zebrafish (Danio rerio) embryo model evaluate mortality and teratogenicity after exposure during the first 2 days post-fertilization. Here we describe an automated image-based high content screening (HCS) assay to identify the teratogenic/embryotoxic potential of compounds in zebrafish embryos in vivo. Automated image acquisition was performed using a high content microscope system. Further automated analysis of embryo length, as a statistically quantifiable endpoint of toxicity, was performed on images post-acquisition. The biological effects of ethanol, nicotine, ketamine, caffeine, dimethyl sulfoxide and temperature on zebrafish embryos were assessed. This automated developmental toxicity assay, based on a growth-retardation endpoint should be suitable for evaluating the effects of potential teratogens and developmental toxicants in a high throughput manner. This approach can significantly expedite the screening of potential teratogens and developmental toxicants, thereby improving the current risk assessment process by decreasing analysis time and required resources.

Prenatal caffeine intake differently affects synaptic proteins during fetal brain development

Caffeine is the psychostimulant most consumed worldwide. However, little is known about its effects during fetal brain development. In this study, adult female Wistar rats received caffeine in drinking water (0.1, 0.3 and 1.0 g/L) during the active cycle in weekdays, two weeks before mating and throughout pregnancy. Cerebral cortex and hippocampus from embryonic stages 18 or 20 (E18 or E20, respectively) were collected for immunodetection of the following synaptic proteins: brain-derived neurotrophic factor (BDNF), TrkB receptor, Sonic Hedgehog (Shh), Growth Associated Protein 43 (GAP-43) and Synaptosomal-associated Protein 25 (SNAP-25). Besides, the estimation of NeuN-stained nuclei (mature neurons) and non-neuronal nuclei was verified in both brain regions and embryonic periods. Caffeine (1.0 g/L) decreased the body weight of embryos at E20. Cortical BDNF at E18 was decreased by caffeine (1.0 g/L), while it increased at E20, with no major effects on TrkB receptors. In the hippocampus, caffeine decreased TrkB receptor only at E18, with no effects on BDNF. Moderate and high doses of caffeine promoted an increase in Shh in both brain regions at E18, and in the hippocampus at E20. Caffeine (0.3g/L) decreased GAP-43 only in the hippocampus at E18. The NeuN-stained nuclei increased in the cortex at E20 by lower dose and in the hippocampus at E18 by moderate dose. Our data revealed that caffeine transitorily affect synaptic proteins during fetal brain development. The increased number of NeuN-stained nuclei by prenatal caffeine suggests a possible acceleration of the telencephalon maturation. Although some modifications in the synaptic proteins were transient, our data suggest that caffeine even in lower doses may alter the fetal brain development.

Embryonic caffeine exposure acts via A1 adenosine receptors to alter adult cardiac function and DNA methylation in mice

Evidence indicates that disruption of normal prenatal development influences an individual's risk of developing obesity and cardiovascular disease as an adult. Thus, understanding how in utero exposure to chemical agents leads to increased susceptibility to adult diseases is a critical health related issue. Our aim was to determine whether adenosine A1 receptors (A1ARs) mediate the long-term effects of in utero caffeine exposure on cardiac function and whether these long-term effects are the result of changes in DNA methylation patterns in adult hearts. Pregnant A1AR knockout mice were treated with caffeine (20 mg/kg) or vehicle (0.09% NaCl) i.p. at embryonic day 8.5. This caffeine treatment results in serum levels equivalent to the consumption of 2–4 cups of coffee in humans. After dams gave birth, offspring were examined at 8–10 weeks of age. A1AR+/+ offspring treated in utero with caffeine were 10% heavier than vehicle controls. Using echocardiography, we observed altered cardiac function and morphology in adult mice exposed to caffeine in utero. Caffeine treatment decreased cardiac output by 11% and increased left ventricular wall thickness by 29% during diastole. Using DNA methylation arrays, we identified altered DNA methylation patterns in A1AR+/+ caffeine treated hearts, including 7719 differentially methylated regions (DMRs) within the genome and an overall decrease in DNA methylation of 26%. Analysis of genes associated with DMRs revealed that many are associated with cardiac hypertrophy. These data demonstrate that A1ARs mediate in utero caffeine effects on cardiac function and growth and that caffeine exposure leads to changes in DNA methylation.

[Caffeine in analgesics--myth or medicine?]

Caffeine as an analgesic adiuvant has been discussed for many years. In a recent Cochrane review based on 19 studies with a total of 7238 patients, caffeine enhanced the efficacy of paracetamol, ibuprofen or aspirin with a number needed to treat (NNT) of about 16, comparable to the effect of doubling the dose of the primary analgesic, reported by other authors. Analgesia by caffeine is best explained by antagonism at adenosine receptors. Recent studies confirmed a favourable tolerability profile of caffeine when consumed in "normal" quantities (e.g. 300 mg or about 3 cups of coffee per day), including possible cardiovascular risks, effects on bone density, and exposure in pregnancy. Beneficial effects are known,e.g.,in Parkinson's disease and liver cirrhosis and fibrosis. Caffeine remains an analgesic adiuvant with a favourable risk-benefit balance.

The Janus face of caffeine

Caffeine is certainly the psychostimulant substance most consumed worldwide. Over the past years, chronic consumption of caffeine has been associated with prevention of cognitive decline associated to aging and mnemonic deficits of brain disorders. While its preventive effects have been reported extensively, the cognitive enhancer properties of caffeine are relatively under debate. Surprisingly, there are scarce detailed ontogenetic studies focusing on neurochemical parameters related to the effects of caffeine during prenatal and earlier postnatal periods. Furthermore, despite the large number of epidemiological studies, it remains unclear how safe is caffeine consumption during pregnancy and brain development. Thus, the purpose of this article is to review what is currently known about the actions of caffeine intake on neurobehavioral and adenosinergic system during brain development. We also reviewed other neurochemical systems affected by caffeine, but not only during brain development. Besides, some recent epidemiological studies were also outlined with the control of "pregnancy signal" as confounding variable. The idea is to tease out how studies on the impact of caffeine consumption during brain development deserve more attention and further investigation.

Is caffeine consumption safe during pregnancy?

QUESTION

I have a pregnant patient who experienced a miscarriage in the past and who has asked me whether her consumption of 2 cups of coffee per day could have caused it. What should I tell her?

ANSWER

There are conflicting data on the fetal safety of dietary caffeine consumption during pregnancy, particularly at levels of 300 mg/d or greater. Although it is difficult to assess the risk of spontaneous abortion with caffeine consumption, most of the data do not suggest an increased risk of adverse pregnancy, fertility, or neurodevelopmental outcomes with caffeine consumption of 300 mg/d or less from all sources. Therefore, consumption of 1 to 2 cups of coffee a day is not expected to be a concern.

Maternal caffeine consumption has irreversible effects on reproductive parameters and fertility in male offspring rats

OBJECTIVE

Concerns are growing about the decrease in male reproductive health. Caffeine is one of the popular nutrients that has been implicated as a risk factor for infertility. In the present study, we examined whether in utero and lactational exposure to caffeine affects the reproductive function of the offspring of rats.

METHODS

Pregnant rats received caffeine via drinking water during gestation (26 and 45 mg/kg) and lactation (25 and 35 mg/kg). Body and reproductive organ weight, seminiferous tubule diameter, germinal epithelium height, sperm parameters, fertility rate, number of implantations, and testosterone level of the offspring were assessed from birth to adulthood.

RESULTS

Significant dose-related decreases were observed in the body and reproductive organ weight, seminiferous tubule diameter, and germinal epithelium height of the offspring. Sperm density had declined significantly in offspring of the low-dose and high-dose groups, by 8.81% and 19.97%, respectively, by postnatal day 150. The number of viable fetuses had decreased significantly in females mated with male offspring of the high-dose group at postnatal days 60, 90, 120, and 150. There were also significant reductions in testosterone levels of high-dose group offspring from birth to postnatal day 150.

CONCLUSION

It is concluded that maternal caffeine consumption impairs gonadal development and has long-term adverse effects on the reproductive efficiency of male offspring rats.

Health risks of energy drinks: what nurses and consumers need to know

Energy drinks have become very popular, yet they present health concerns and workplace safety issues related to mental and physical effects of the drinks, which are mainly related to the central nervous system and include heightened alertness, altered sleep patterns, arrhythmias and, rarely, seizures. In the workplace, any pharmacologic agent or substance, such as energy drinks, may present a risk to the delivery of health care, and the use energy drinks during pregnancy and lactation are a concern and patient education is warranted.

Caffeine-induced fetal rat over-exposure to maternal glucocorticoid and histone methylation of liver IGF-1 might cause skeletal growth retardation

Several epidemiological investigations, including previous work by our laboratory, indicate that maternal caffeine consumption is associated with intrauterine growth retardation and impaired fetal length growth. Skeletal development is critical for length growth. In the present study, our goals were to determine the effects of prenatal caffeine exposures on fetal skeletal growth and to investigate the mechanisms associated with such effects. Pregnant Wistar rats were injected intragastrically with 120mg/kg of caffeine intragastrically each day from gestational days 11-20. Maternal prenatal caffeine exposure was associated with decreased fetal femur lengths and inhibited of synthesis of extracellular matrices in fetal growth plates Moreover, caffeine exposure significantly increased the levels of fetal blood corticosterone and decreased IGF-1mRNA expression levels in the liver and growth plate. The expression levels of IGF-1 signaling pathway components (IGF-1R, IRS-1, AKT1/2 and Col2A1) were also reduced. In addition, the results of chromatin immunoprecipitation assays indicated that caffeine exposure down-regulated histone methylation of fetal IGF-1 in the liver. These results suggest that prenatal caffeine exposure may inhibit fetal skeletal growth through a mechanism that is associated with increased fetal exposure to maternal glucocorticoids and results in lower IGF-1 signaling pathway activity. Taken together, these results raise important concerns regarding the skeletal growth toxicity of caffeine and potentially indicate the intrauterine origins of adult osteoporosis and osteoarthritis.

Caffeine inhibits EGF-stimulated trophoblast cell motility through the inhibition of mTORC2 and Akt

Impaired trophoblast invasion is associated with pregnancy disorders such as early pregnancy loss and preeclampsia. There is evidence to suggest that the consumption of caffeine during pregnancy may increase the risk of pregnancy loss; however, little is known about the direct effect of caffeine on normal trophoblast biology. Our objectives were to examine the effect of caffeine on trophoblast migration and motility after stimulation with epidermal growth factor (EGF) and to investigate the intracellular signaling pathways involved in this process. Primary first-trimester extravillous trophoblasts (EVT) and the EVT-derived cell line SGHPL-4 were used to study the effect of caffeine on EGF-stimulated cellular motility using time-lapse microscopy. SGHPL-4 cells were further used to study the effect of caffeine and cAMP on EGF-stimulated invasion of fibrin gels. The influence of caffeine and cAMP on EGF-stimulated intracellular signaling pathways leading to the activation of Akt were investigated by Western blot analysis. Caffeine inhibits both EGF-stimulated primary EVT and SGHPL-4 cell motility. EGF stimulation activates phosphatidylinositol 3-kinase, and Akt and caffeine inhibit this activation. Although cAMP inhibits both motility and invasion, it does not inhibit the activation of Akt, indicating that the effects of caffeine seen in this study are independent of cAMP. Further investigation indicated a role for mammalian target of rapamycin complex 2 (mTORC2) as a target for the inhibitory effect of caffeine. In conclusion, we demonstrate that caffeine inhibits EGF-stimulated trophoblast invasion and motility in vitro and so could adversely influence trophoblast biology in vivo.

A hypothalamic-pituitary-adrenal axis-associated neuroendocrine metabolic programmed alteration in offspring rats of IUGR induced by prenatal caffeine ingestion

Caffeine is a definite factor of intrauterine growth retardation (IUGR). Previously, we have confirmed that prenatal caffeine ingestion inhibits the development of hypothalamic-pituitary-adrenal (HPA) axis, and alters the glucose and lipid metabolism in IUGR fetal rats. In this study, we aimed to verify a programmed alteration of neuroendocrine metabolism in prenatal caffeine ingested-offspring rats. The results showed that prenatal caffeine (120 mg/kg.day) ingestion caused low body weight and high IUGR rate of pups; the concentrations of blood adrenocorticotropic hormone (ACTH) and corticosterone in caffeine group were significantly increased in the early postnatal period followed by falling in late stage; the level of blood glucose was unchanged, while blood total cholesterol (TCH) and triglyceride (TG) were markedly enhanced in adult. After chronic stress, the concentrations and the gain rates of blood ACTH and corticosterone were obviously increased, meanwhile, the blood glucose increased while the TCH and TG decreased in caffeine group. Further, the hippocampal mineralocorticoid receptor (MR) expression in caffeine group was initially decreased and subsequently increased after birth. After chronic stress, the 11β-hydroxysteroid dehydrogenase-1, glucocorticoid receptor (GR), MR as well as the MR/GR ratio were all significantly decreased. These results suggested that prenatal caffeine ingestion induced the dysfunction of HPA axis and associated neuroendocrine metabolic programmed alteration in IUGR offspring rats, which might be related with the functional injury of hippocampus. These observations provide a valuable experimental basis for explaining the susceptibility of IUGR offspring to metabolic syndrome and associated diseases.

Maternal caffeine consumption and risk of congenital limb deficiencies

BACKGROUND

Animal studies have shown that high doses of caffeine might cause congenital limb deficiencies (LDs); however, no epidemiologic studies have explored this relation.

METHODS

This case-control study assessed associations between maternal dietary caffeine and congenital LDs using data from the National Birth Defects Prevention Study (NBDPS), with 844 LD cases and 8069 controls from 1997 to 2007. Caffeine intakes from beverages (coffee, tea, and soda) and chocolate combined and by beverage type were examined. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated for subtypes of isolated LDs (no additional major anomalies) and LDs with other major anomalies separately, comparing the odds of 10 to <100, 100 to <200, 200 to <300, and 300+ mg/day total caffeine intake to 0 to <10 mg/day.

RESULTS

All total dietary caffeine intake categories of 10 mg/day and above were marginally associated with odds of all isolated LDs combined (aOR, 1.4-1.7), isolated longitudinal LDs (aOR, 1.2-1.6), and isolated transverse LDs (aOR, 1.3-1.8) compared to the lowest intake category. A dose-response pattern for total dietary caffeine intake was not observed.

CONCLUSIONS

A weak increased risk of congenital LDs associated with maternal dietary caffeine consumption was observed in this study; however, risk did not vary by amount of caffeine consumed.

Caffeine intake during pregnancy and risk of problem behavior in 5- to 6-year-old children

BACKGROUND AND OBJECTIVE

Human studies that have investigated the association between caffeine intake during pregnancy and offspring's behavioral outcomes are scant and inconclusive. We prospectively investigated the association between maternal caffeine intake during pregnancy and children's problem behavior at age 5 to 6 years. Mediation by fetal growth restriction and gestational age as well as effect modification by the child's gender and maternal smoking was tested.

METHODS

In a community based multiethnic birth cohort, dietary caffeine intake (coffee, caffeinated tea, and cola) was measured (maternal self-report, n = 8202) around the 16th week of gestation. At age 5, children's overall problem behavior, emotional problems, conduct problems, hyperactivity/inattention problems, peer relationship problems, and prosocial behavior were rated by both mother and teacher (n = 3439) with the Strengths and Difficulties Questionnaire. Analyses were adjusted for maternal age, ethnicity, cohabitant status, education, smoking and alcohol consumption during pregnancy, child's gender, family size, and prenatal maternal anxiety.

RESULTS

Caffeine intake was not associated with a higher risk for behavior problems or with suboptimal prosocial behavior. No evidence was found for mediation by fetal growth restriction or gestational age, nor for effect modification by the child's gender.

CONCLUSIONS

Results did not provide evidence for developmental programming influences of intrauterine exposure to caffeine on offspring's problem behavior at age 5. Present results give no indication to advise pregnant women to reduce their caffeine intake to prevent behavior problems in their children.

Caffeine reduces 11β-hydroxysteroid dehydrogenase type 2 expression in human trophoblast cells through the adenosine A(2B) receptor

Maternal caffeine consumption is associated with reduced fetal growth, but the underlying molecular mechanisms are unknown. Since there is evidence that decreased placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) is linked to fetal growth restriction, we hypothesized that caffeine may inhibit fetal growth partly through down regulating placental 11β-HSD2. As a first step in examining this hypothesis, we studied the effects of caffeine on placental 11β-HSD2 activity and expression using our established primary human trophoblast cells as an in vitro model system. Given that maternal serum concentrations of paraxanthine (the primary metabolite of caffeine) were greater in women who gave birth to small-for-gestational age infants than to appropriately grown infants, we also studied the effects of paraxanthine. Our main findings were: (1) both caffeine and paraxanthine decreased placental 11β-HSD2 activity, protein and mRNA in a concentration-dependent manner; (2) this inhibitory effect was mediated by the adenosine A(2B) receptor, since siRNA-mediated knockdown of this receptor prevented caffeine- and paraxanthine-induced inhibition of placental 11β-HSD2; and (3) forskolin (an activator of adenyl cyclase and a known stimulator of 11β-HSD2) abrogated the inhibitory effects of both caffeine and paraxanthine, which provides evidence for a functional link between exposure to caffeine and paraxanthine, decreased intracellular levels of cAMP and reduced placental 11β-HSD2. Taken together, these findings reveal that placental 11β-HSD2 is a novel molecular target through which caffeine may adversely affect fetal growth. They also uncover a previously unappreciated role for the adenosine A(2B) receptor signaling in regulating placental 11β-HSD2, and consequently fetal development.

Fetal rat metabonome alteration by prenatal caffeine ingestion probably due to the increased circulatory glucocorticoid level and altered peripheral glucose and lipid metabolic pathways

The aims of this study were to clarify the metabonome alteration in fetal rats after prenatal caffeine ingestion and to explore the underlying mechanism pertaining to the increased fetal circulatory glucocorticoid (GC). Pregnant Wistar rats were daily intragastrically administered with different doses of caffeine (0, 20, 60 and 180 mg/kg) from gestational days (GD) 11 to 20. Metabonome of fetal plasma and amniotic fluid on GD20 were analyzed by ¹H nuclear magnetic resonance-based metabonomics. Gene and protein expressions involved in the GC metabolism, glucose and lipid metabolic pathways in fetal liver and gastrocnemius were measured by real-time RT-PCR and immunohistochemistry. Fetal plasma metabonome were significantly altered by caffeine, which presents as the elevated α- and β-glucose, reduced multiple lipid contents, varied apolipoprotein contents and increased levels of a number of amino acids. The metabonome of amniotic fluids showed a similar change as that in fetal plasma. Furthermore, the expressions of 11β-hydroxysteroid dehydrogenase 2 (11β-HSD-2) were decreased, while the level of blood GC and the expressions of 11β-HSD-1 and glucocorticoid receptor (GR) were increased in fetal liver and gastrocnemius. Meanwhile, the expressions of insulin-like growth factor 1 (IGF-1), IGF-1 receptor and insulin receptor were decreased, while the expressions of adiponectin receptor 2, leptin receptors and AMP-activated protein kinase α2 were increased after caffeine treatment. Prenatal caffeine ingestion characteristically change the fetal metabonome, which is probably attributed to the alterations of glucose and lipid metabolic pathways induced by increased circulatory GC, activated GC metabolism and enhanced GR expression in peripheral metabolic tissues.

Maternal caffeine consumption and infant nighttime waking: prospective cohort study

OBJECTIVE

Coffee and other caffeinated beverages are commonly consumed in pregnancy. In adults, caffeine may interfere with sleep onset and have a dose-response effect similar to those seen during insomnia. In infancy, nighttime waking is a common event. With this study, we aimed to investigate if maternal caffeine consumption during pregnancy and lactation leads to frequent nocturnal awakening among infants at 3 months of age.

METHODS

All children born in the city of Pelotas, Brazil, during 2004 were enrolled on a cohort study. Mothers were interviewed at delivery and after 3 months to obtain information on caffeine drinking consumption, sociodemographic, reproductive, and behavioral characteristics. Infant sleeping pattern in the previous 15 days was obtained from a subsample. Night waking was defined as an episode of infant arousal that woke the parents during nighttime. Multivariable analysis was performed by using Poisson regression.

RESULTS

The subsample included 885 of the 4231 infants born in 2004. All but 1 mother consumed caffeine in pregnancy. Nearly 20% were heavy consumers (≥300 mg/day) during pregnancy and 14.3% at 3 months postpartum. Prevalence of frequent nighttime awakeners (>3 episodes per night) was 13.8% (95% confidence interval: 11.5%-16.0%). The highest prevalence ratio was observed among breastfed infants from mothers consuming ≥300 mg/day during the whole pregnancy and in the postpartum period (1.65; 95% confidence interval: 0.86-3.17) but at a nonsignificant level.

CONCLUSIONS

Caffeine consumption during pregnancy and by nursing mothers seems not to have consequences on sleep of infants at the age of 3 months.

Caffeine treatment disturbs the angiogenesis of zebrafish embryos

Caffeine is a widely consumed substance that occurs in numerous dietary sources, but teratogenic effects of caffeine intake during embryonic development are still not clear. In the present study, we used the zebrafish as a model to assess caffeine-induced toxicity on embryonic vascular development. A green fluorescent vascular endothelium transgenic line, Tg(fli1:egfp), was utilized for the sensitive detection of vascular development, including vasculo- and angiogenesis. Caffeine-treated embryos showed no defects in vasculogenesis, but revealed dose-dependent (250-350 ppm) developmental defects in intersegmental vessels, dorsal longitudinal anastomotic vessels, and subintestinal vein sprouting. Further, real-time polymerase chain reaction analysis of caffeine-treated embryos showed an upregulation of nrp1a along with a downregulation of sema3aa and sema3c. In conclusion, caffeine treatment induces defects of angiogenesis in zebrafish embryos.

Caffeinated beverage intake and reproductive hormones among premenopausal women in the BioCycle Study

BACKGROUND

Caffeinated beverages are widely consumed among women of reproductive age, but their association with reproductive hormones, and whether race modifies any such associations, is not well understood.

OBJECTIVE

We assessed the relation between caffeine and caffeinated beverage intake and reproductive hormones in healthy premenopausal women and evaluated the potential effect modification by race.

DESIGN

Participants (n = 259) were followed for up to 2 menstrual cycles and provided fasting blood specimens for hormonal assessment at up to 8 visits per cycle and four 24-h dietary recalls per cycle. Weighted linear mixed models and nonlinear mixed models with harmonic terms were used to estimate associations between caffeine and hormone concentrations, adjusted for age, adiposity, physical activity, energy and alcohol intakes, and perceived stress. On the basis of a priori assumptions, an interaction between race and caffeine was tested, and stratified results are presented.

RESULTS

Caffeine intake ≥200 mg/d was inversely associated with free estradiol concentrations among white women (β = -0.15; 95% CI: -0.26, -0.05) and positively associated among Asian women (β = 0.61; 95% CI: 0.31, 0.92). Caffeinated soda intake and green tea intake ≥1 cup/d (1 cup = 240 mL) were positively associated with free estradiol concentrations among all races: β = 0.14 (95% CI: 0.06, 0.22) and β = 0.26 (95% CI: 0.07, 0.45), respectively.

CONCLUSIONS

Moderate consumption of caffeine was associated with reduced estradiol concentrations among white women, whereas caffeinated soda and green tea intakes were associated with increased estradiol concentrations among all races. Further research is warranted on the association between caffeine and caffeinated beverages and reproductive hormones and whether these relations differ by race.