Pharmacogenetics of drug-induced birth defects: what is known so far?

Valproic acid promotes SOD2 acetylation: A potential mechanism of valproic acid-induced oxidative stress in developing systems

Valproic acid (VPA) is an antiepileptic, bipolar and migraine medication, which is associated with embryonic dysmorphology, more specifically neural tube defects (NTDs), if taken while pregnant. One mechanism by which VPA may cause NTDs is through oxidative stress that cause disruption of cell signaling. However, mechanisms of VPA-induced oxidative stress are not fully understood. Since VPA is a deacetylase inhibitor, we propose that VPA promotes mitochondrial superoxide dismutase-2 (SOD2) acetylation, decreasing SOD2 activity and increasing oxidant levels. Using the pluripotent embryonal carcinoma cell line, P19, VPA effects were evaluated in undifferentiated and neurodifferentiated cells. VPA treatments increased oxidant levels, oxidized the glutathione (GSH)/glutathione disulfide (GSSG) redox couple, and decreased total SOD and SOD2 activity in undifferentiated P19 cells but not in differentiated P19 cells. VPA caused a specific increase in mitochondrial oxidants in undifferentiated P19 cells, VPA did not alter respirometry measurements. Immunoblot analyses demonstrated that VPA increased acetylation of SOD2 at lysine⁶⁸ (AcK68 SOD2) in undifferentiated P19 cells but not in differentiated P19 cells. Pretreatments with the Nrf2 inducer, dithiol-3-thione (D3T), in undifferentiated P19 cells prevented increased oxidant levels, GSH/GSSG redox oxidation and restored total SOD and SOD2 activity, correlating with a decrease in AcK68 SOD2 levels. In embryos, VPA decreased total SOD and SOD2 activity and increased levels of AcK68 SOD2, and D3T pretreatments prevented VPA effects, increasing total SOD and SOD2 activity and lowering levels of AcK68 SOD2. These data demonstrate a potential, contributing oxidizing mechanism by which VPA incites teratogenesis in developing systems. Moreover, these data also suggest that Nrf2 interventions may serve as a means to protect developmental signaling and inhibit VPA-induced malformations.

Selective Serotonin Reuptake Inhibitor (SSRI) Antidepressants in Pregnancy and Congenital Anomalies: Analysis of Linked Databases in Wales, Norway and Funen, Denmark

Background

Hypothesised associations between in utero exposure to selective serotonin reuptake inhibitors (SSRIs) and congenital anomalies, particularly congenital heart defects (CHD), remain controversial. We investigated the putative teratogenicity of SSRI prescription in the 91 days either side of first day of last menstrual period (LMP).

Methods and Findings

Three population-based EUROCAT congenital anomaly registries- Norway (2004–2010), Wales (2000–2010) and Funen, Denmark (2000–2010)—were linked to the electronic healthcare databases holding prospectively collected prescription information for all pregnancies in the timeframes available. We included 519,117 deliveries, including foetuses terminated for congenital anomalies, with data covering pregnancy and the preceding quarter, including 462,641 with data covering pregnancy and one year either side. For SSRI exposures 91 days either side of LMP, separately and together, odds ratios with 95% confidence intervals (ORs, 95%CI) for all major anomalies were estimated. We also explored: pausing or discontinuing SSRIs preconception, confounding, high dose regimens, and, in Wales, diagnosis of depression. Results were combined in meta-analyses. SSRI prescription 91 days either side of LMP was associated with increased prevalence of severe congenital heart defects (CHD) (as defined by EUROCAT guide 1.3, 2005) (34/12,962 [0.26%] vs. 865/506,155 [0.17%] OR 1.50, 1.06–2.11), and the composite adverse outcome of 'anomaly or stillbirth' (473/12962, 3.65% vs. 15829/506,155, 3.13%, OR 1.13, 1.03–1.24). The increased prevalence of all major anomalies combined did not reach statistical significance (3.09% [400/12,962] vs. 2.67% [13,536/506,155] OR 1.09, 0.99–1.21). Adjusting for socio-economic status left ORs largely unchanged. The prevalence of anomalies and severe CHD was reduced when SSRI prescriptions were stopped or paused preconception, and increased when >1 prescription was recorded, but differences were not statistically significant. The dose-response relationship between severe CHD and SSRI dose (meta-regression OR 1.49, 1.12–1.97) was consistent with SSRI-exposure related risk. Analyses in Wales suggested no associations between anomalies and diagnosed depression.

Conclusion

The additional absolute risk of teratogenesis associated with SSRIs, if causal, is small. However, the high prevalence of SSRI use augments its public health importance, justifying modifications to preconception care.

Pharmacogenomics of preterm birth prevention and treatment

Pharmacogenomics and personalised medicine incorporate genetic factors, historical data, and environmental exposures to predict individual variation in response to medications. The study of pharmacology and pharmacogenomics is challenging in obstetrics, and our knowledge in this area lags behind other disciplines of medicine. Some preliminary data, however, suggest that some of the interindividual variation seen in response to medications given for the prevention (progesterone) and the treatment (nifedipine, terbutaline, and others) of preterm labour may be caused by pharmacogenomic effects. A comprehensive approach, integrating clinical data, environmental factors, including concomitant medications and genotype, to optimise the prevention and treatment strategies for preterm birth, is urgently needed.

TWEETABLE ABSTRACT

Some of the variation to meds for prematurity prevention/treatment may arise from pharmacogenomic effects.

Treatment of acute abdominal pain in the emergency room: a systematic review of the literature

Appropriate pain therapy prior to diagnosis in patients with acute abdominal pain remains controversial. Several recent studies have demonstrated that pain therapy does not negatively influence either the diagnosis or subsequent treatment of these patients; however, current practice patterns continue to favour withholding pain medication prior to diagnosis and surgical treatment decision. A systematic review of PubMed, Web-of-Science and The-Cochrane-Library from 1929 to 2011 was carried out using the key words of 'acute', 'abdomen', 'pain', 'emergency' as well as different pain drugs in use, revealed 84 papers. The results of the literature review were incorporated into six sections to describe management of acute abdominal pain: (1) Physiology of Pain; (2) Common Aetiologies of Abdominal Pain; (3) Pre-diagnostic Analgesia; (4) Pain Therapy for Acute Abdominal Pain; (5) Analgesia for Acute Abdominal Pain in Special Patient Populations; and (6) Ethical and Medico-legal Considerations in Current Analgesia Practices. A comprehensive algorithm for analgesia for acute abdominal pain in the general adult population was developed. A review of the literature of common aetiologies and management of acute abdominal pain in the general adult population and special patient populations seen in the emergency room revealed that intravenous administration of paracetamol, dipyrone or piritramide are currently the analgesics of choice in this clinical setting. Combinations of non-opioids and opioids should be administered in patients with moderate, severe or extreme pain, adjusting the treatment on the basis of repeated pain assessment, which improves overall pain management.

Genetic susceptibility to teratogens: state of the art

There is evidence that the susceptibility to the teratogenic effect of drugs within human populations varies extremely from one individual to another, even after identical exposures. One of the factors that may explain these interindividual differences is the genetic makeup in the pharmacokinetics and pharmacodynamics of the respective drugs. In fact, both maternal and embryonic/fetal genotypes can affect placental transport, absorption, metabolism, distribution and receptor binding of an agent, influencing its teratogenicity. We have reviewed the literature and commented on the reported correlations between genetic factors and drug-induced birth defects. There is still a clear lack of knowledge regarding this issue and the available data are often conflicting. However, the identification of specific polymorphisms associated with predisposition to teratogenesis may allow in the future the development of personalized non-teratogenic therapies for pregnant women.