Maternal exposure to prescription and non-prescription pharmaceuticals or drugs of abuse and risk of craniosynostosis

High-dose retinoic acid modulates rat calvarial osteoblast biology

Retinoic acid has been shown to adversely affect craniofacial development. Cleft palate and craniosynostosis are two examples of craniofacial defects associated with prenatal exposure to this agent. Although the effects of retinoic acid on cephalic neural crest-derived tissues have previously been studied, the specific effects of retinoic acid on the cellular biology of osteoblasts remain unclear. The purpose of this study was to analyze in detail the effects of pharmacologic doses of retinoic acid on the differentiation and proliferation of osteoblasts derived from an intramembranous source. Primary rat calvarial osteoblasts were established in culture and treated with 1 or 10 microM all-trans-retinoic acid. Retinoic acid treatment markedly increased expression of osteopontin up to 48 h after stimulation. Consistent with this early stage of differentiation, both mRNA and protein analysis of FGF receptor isoforms demonstrated a switch in predominance from fibroblast growth factor receptor 2 (fgfr2) to fgfr1. Analysis of PCNA protein confirmed inhibition of proliferation by retinoic acid. To determine whether these alterations in osteoblast biology would lead to increased differentiation, we examined short term [alkaline phosphatase (AP) activity] and long term (von Kossa staining) surrogates of bone formation in vitro. These assays confirmed that retinoic acid increased osteogenesis, with a 4-fold increase in bone nodule formation in cells treated with 10 microM retinoic acid after 28 days. Overall, our results demonstrated that pharmacologic doses of all-trans-retinoic acid decreased osteoblast proliferation and increased differentiation, suggesting that retinoic acid may effect craniofacial development by pathologically enhancing osteogenesis.

Common craniofacial anomalies: facial clefts and encephaloceles

The wide variety of craniofacial malformations makes classification difficult. A simple classification system allows an overview of the current understanding of the causes, assessments, and treatments of the most frequently encountered craniofacial anomalies. Facial clefts and encephaloceles are reviewed with respect to their diverse causes, pathogenesis, anatomical features, and treatments. Approaches to the surgical treatment of these conditions are reviewed.

A study of drug use during pregnancy in a teaching hospital in western Nepal

Information on the use of drugs during pregnancy is scarce and rather anecdotal. Careful consideration of the benefit to the mother and the risk to the fetus is required when prescribing drugs during pregnancy. The aim of this study was to gain knowledge on this issue in western Nepal. 2156 prescriptions of pregnant women were collected at random from the antenatal care (ANC) in obstetrics out-patient department (OPD) at Manipal Teaching Hospital (MTH), Nepal and analyzed for this study. The mean maternal age and hemoglobin concentration were 25 years and 12.21 g/dl, respectively. Twenty-three percent women attended obstetric OPD due to maternal disorders other than routine ANC (77%). Problem oriented drug use was due to nausea/vomiting (4.7%), dyspepsia (3.1%), and per vaginal spotting/bleeding (3.4%), mainly. Most of the women got 2-3 drugs and commonly included nutritional supplementation and tetanus toxoid. The average number of drugs/prescription was 2.00, 15.37% and 64.8% drugs were prescribed by generic name and as fixed dose combinations, respectively. The most commonly prescribed drugs were nutritional supplements like iron, folate, calcium, vitamins (72.8%), followed by tetanus toxoid (12.4%), gastrointestinals (5%), antimicrobials (4.6%), etc. Though, the selection of drugs was rational in most of the cases, some anomalies were observed and discussed with the clinicians. Our data reflect the general extent and prescribing pattern for those Nepalese pregnant women attending hospital in western Nepal.

New insights into craniosynostosis

Craniosynostosis is a congenital developmental disorder involving premature fusion of cranial sutures, often associated with multiple neurological manifestations. The perspective of this group of disorders has changed dramatically in the new era of molecular genetics. In the last decade a large literature with new concepts in craniosynostosis has appeared. More than 100 syndromes associated with craniosynostosis have been described, and in about a dozen, the molecular defect has been identified. Pediatric neurologists are less aware than geneticists, neurosurgeons, and craniofacial surgeons of these changes. General concepts about craniosynostosis are here presented with updates of clinical and genetic aspects of well-defined syndromes such as Apert, Crouzon, Pfeiffer, Saethre-Chotzen. Evidence of their relationship with fibroblast growth factor receptors (FGFRs) 1, 2, and 3, and with causative genes such as TWIST has been documented. New and other less common syndromes also are discussed. The differences between positional and synostotic plagiocephaly are important, as well as the cause of nonsyndromic craniosynostosis. The prognosis and neurological outcome of patients, including "benign" forms of craniosynostosis, are other important aspects. Major advances have occurred in understanding pathogenesis, diagnosis, and treatment of craniosynostosis. The role of local dura mater and apoptosis; modalities of imaging such as prenatal ultrasound and three-dimensional and spiral CT have improved the accuracy in diagnosis, and the new approaches in surgical treatment involving efficient and less invasive methods, are evidence of these advances.

Genetic and environmental risk factors for sagittal craniosynostosis

The authors investigated whether genetic and environmental factors influence risk for sagittal craniosynostosis. Cases were ascertained from craniofacial clinics in the Baltimore-Washington metropolitan region. Controls were recruited from the Johns Hopkins newborn nursery and a large pediatric practice in Baltimore County. Forty-two probands with isolated, nonsyndromic sagittal craniosynostosis born in the mid-Atlantic region were included in this analysis. Controls are infants born in Maryland without any known birth defects (n = 182). Odds ratios (OR) and corresponding 95% confidence intervals (CI) were calculated. Cases were genotyped at several loci implicated in malformation syndromes including craniosynostosis. There were no elevated risks for craniosynostosis related to maternal or paternal smoking or maternal vitamin usage. Case mothers consumed less alcohol (OR = 0.38, 95% CI = 0.17-0.85) and had less education than control mothers ( < 0.001). All cases that were sequenced were negative for mutations at the following genes: exon IIIa 755C->G, (exons IIIa and IIIc,), exon IIIa, and exon 1. These findings suggest that whereas TWIST and the genes are important for syndromic craniosynostosis, they are unlikely to be involved in isolated sagittal craniosynostosis. Parental education and alcohol consumption were associated with sagittal craniosynostosis in this study.

Update on new developments in the study of human teratogens

BACKGROUND AND METHODS

The purpose of this annual article is to highlight and briefly review new and significant information on agents that may be teratogenic in pregnant women. Various sources of on-line and printed information are given.

RESULTS

The following topics have been discussed: 1) lithium medication: decreased estimate of risk; 2) cigarette smoking and genotype as contributors to oral-facial clefts and clubfoot; 3) trimethoprim; 4) methimazole syndrome?; 5) glucocorticoids and oral-facial clefts; 6) binge drinking; 7) fetal valproate syndrome; and 8) carbamazepine.

CONCLUSIONS

We have highlighted several maternal exposures during pregnancy that are associated with small but increased rates of birth defects, generally only a few cases per 1,000 infants. These exposures include cigarette smoking, and treatment with lithium, trimethoprim, methimazole, or corticosteroids. This weak teratogenic effect was usually identified by the linkage of an uncommon treatment with an unusual birth defect outcome. The use of modern epidemiologic techniques, especially prospective multicenter studies that provide increased numbers, has helped to strengthen the evidence for these associations. We discuss how teratogenic risks that are small in comparison to the background risk can be presented to at-risk women and their doctors. We have briefly listed some elements that might be used in prioritizing further studies of suspected teratogenic exposures. Various existing methods for expressing the strength of evidence for human teratogenicity are also given.

[Metopic craniosynostosis, probable effect of intrauterine exposure to maternal valproate treatment]

Metopic craniosynostosis may be an adverse effect of valproic acid exposed fetus.

CASES

We report two infants with metopic craniosynostosis, born to mothers who were treated with valproic acid. In one case, a prenatal diagnosis was made. In the other case, only the male dizygotic twin was affected.

CONCLUSION

Trigonocephaly may be a symptom of valproate embryofoetopathy detectable by antenatal ultrasound examination.

Craniosynostosis and fetal exposure to sodium valproate

OBJECT

Fetal valproate syndrome affects one in 10 children born to mothers who ingest sodium valproate regularly during pregnancy. It has been described as producing a combination of typical dysmorphic features and major organ system anomalies. Trigonocephaly is caused by premature fusion of the metopic suture and has not previously been described as a typical feature of the syndrome. The authors reviewed the cases of 2,220 children with craniosynostosis to examine the effect of maternal sodium valproate use on the fetus.

METHODS

Case files of all 2,220 children were reviewed. The type and severity of each patient's craniosynostosis was assessed. Information about maternal health and medication use was obtained, and family interviews were conducted. Children underwent mental development assessment performed using standard tests both pre- and postoperatively. Detailed maternal health information was obtained in 1,676 cases. Of these, 17 mothers were found to have undergone regular treatment with sodium valproate monotherapy at the time of their pregnancies. No other antiepileptic medical regimen was found. All 17 children exhibited trigonocephaly. These patients' intelligence quotients (JQs) at the time of the most recent follow-up examination ranged from 45 to 100, with a mean of 75; IQs were significantly higher in patients who underwent surgery before reaching 6 months of age.

CONCLUSIONS

Ideally any pregnancy in a woman being treated for epilepsy should be planned, and both an obstetrician and a neurologist should be consulted. In children born with fetal valproate syndrome, it is important to be aware of the possibility of metopic suture synostosis, which we believe should be considered part of the syndrome, because early surgical intervention may improve cognitive outcome.

Cranioestenose da sutura metópica: efeito teratogênico do valproato de sódio. Relato de caso

OBJETIVO: alertar que o uso de valproato de sódio durante a gravidez pode determinar cranioestenose no recém-nascido, em especial a trigonocefalia. MÉTODO: relato de um caso de trigonocefalia em menina de 6 meses, filha de pais jovens, não fumantes e cuja mãe fez uso de fenobarbital 100 mg/dia e valproato de sódio 500 mg duas vezes/dia durante toda a gravidez. Foi realizada revisão bibliográfica sobre o assunto. RESULTADO: no ato cirúrgico pôde-se confirmar a presença de esclerose óssea sobre a sutura metópica. A revisão bibliográfica permitiu o encontro de relatos prévios sobre a teratogenicidade do valproato de sódio, que determina principalmente cranioestenose da sutura metópica. CONCLUSÃO: o uso de valproato de sódio durante a gravidez pode determinar como ação teratogênica a cranioestenose, especialmente a trigonocefalia (fechamento precoce da sutura metópica).

Proteomic comparison of human and great ape blood plasma reveals conserved glycosylation and differences in thyroid hormone metabolism

Most blood plasma proteins are glycosylated. These glycoproteins typically carry sialic acid-bearing sugar chains, which can modify the observed molecular weights and isoelectric points of those proteins during electrophoretic analyses. To explore changes in protein expression and glycosylation that occurred during great ape and human evolution, we subjected multiple blood plasma samples from all these species to high-resolution proteomic analysis. We found very few species-specific differences, indicating a remarkable degree of conservation of plasma protein expression and glycosylation during approximately 12 million years of evolution. A few lineage-specific differences in protein migration were noted among the great apes. The only obvious differences between humans and all great apes were an apparent decrease in transthyretin (prealbumin) and a change in haptoglobin isoforms (the latter was predictable from prior genetic studies). Quantitative studies of transthyretin in samples of blood plasma (synthesized primarily by the liver) and of cerebrospinal fluid (synthesized locally by the choroid plexus of the brain) confirmed approximately 2-fold higher levels in chimpanzees compared to humans. Since transthyretin binds thyroid hormones, we next compared plasma thyroid hormone parameters between humans and chimpanzees. The results indicate significant differences in the status of thyroid hormone metabolism, which represent the first known endocrine difference between these species. Notably, thyroid hormones are known to play major roles in the development, differentiation, and metabolism of many organs and tissues, including the brain and the cranium. Also, transthyretin is known to be the major carrier of thyroid hormone in the cerebrospinal fluid, likely regulating delivery of this hormone to the brain. A potential secondary difference in retinoid (vitamin A) metabolism is also noted. The implications of these findings for explaining unique features of human evolution are discussed.