Fluoxetine-induced perinatal morbidity in a sheep model

Progress in the study of the effects of selective serotonin reuptake inhibitors (SSRIs) on the reproductive system

In recent years, the increasing number of infertility cases has led to a greater research focus on the reproductive toxicity of drugs due to the fact that some classes of pharmacotherapeutic agents have been found to exert deleterious effects on the reproductive system. Depressive disorders are a class of common mental illnesses that seriously damage human health. The variety of antidepressant drugs is large and the incidence of adverse effects is high. Selective serotonin reuptake inhibitors (SSRIs), as the first-line drugs for the treatment of depression, have remarkable efficacy, but at the same time there is a widespread abuse of them, which not only creates an unfavorable impact on one's own reproductive system, but also may cause reproductive damage to other non-target populations through pathways, such as the water column. The review provides an introduction to the reproductive toxicity of SSRIs from the aspects of male and female germ cell genesis, embryonic development, reproductive system maturation, and environmental contamination, and it briefly describes the potential mechanisms underlying SSRI-induced reproductive toxicity.

Prenatal treatment with the antidepressant fluoxetine on maternal and neonatal behavior in sheep

BACKGROUND

Fluoxetine is commonly prescribed to treat depression during pregnancy. We aimed to evaluate the effects of prenatal fluoxetine exposure on maternal-offspring behavior in a non-depressed sheep model.

METHODS

On day 119 ± 1 of a 151-day expected gestation, Hampshire ewes were randomly assigned to receive intravenous fluoxetine (10 mg/kg for the first 2 days and 5 mg/kg daily thereafter until parturition) or a control vehicle. Video was recorded of 8 fluoxetine-treated ewes and 10 control ewes for 2 h before and after parturition.

RESULTS

Fluoxetine did not alter dam behavior during the peripartum period, including time spent lying before the first birth, lying bout duration, probability of needing birth assistance, duration of birth assistance when provided, and time spent touching her lambs. However, in utero exposure impaired neonatal vigor as lambs spent less time standing and tended to spend less time nursing compared to unexposed lambs.

CONCLUSION

Neonatal behavioral impairments are consistent with those associated with fluoxetine exposure during human gestation. This effect appears to be independent of maternal behavior, which was unaffected by antidepressant use.

IMPACT

Lambs exposed to SSRI in utero spent less time standing and tended to spend less time nursing than control lambs, consistent with neonatal behavioral outcomes encountered in clinical practice. The reduced neonatal vigor was likely unrelated to maternal behavior, which was not altered by SSRI treatment. Non-depressed sheep models can help to elucidate the behavioral effects of antidepressant use during pregnancy to enhance health outcomes and patient care.

The antidepressant fluoxetine (Prozac®) modulates serotonin signaling to alter maternal peripartum calcium homeostasis

Antidepressant use is two-fold greater in women compared to men; however, most studies have been performed in male subjects. We aimed to understand the impact of selective serotonin reuptake inhibitors (SSRI, most used antidepressants) on calcium homeostasis and steroid metabolism during the peripartum period. Pregnant sheep (n = 10/group) were treated with vehicle or fluoxetine (most common SSRI) during the last month of gestation. Fluoxetine treatment decreased circulating calcium prior to parturition (8.7 ± 0.1 mg/dL vs 8.2 ± 0.1 mg/dL; P = 0.07). In the control group, total calcium decreased after parturition corresponding to the onset of lactogenesis followed by increase in calcium by day 2 postpartum. Interestingly, this normal transient decrease in circulating calcium was absent in fluoxetine-treated ewes. The steroids cortisol and progesterone were not altered by fluoxetine treatment whereas estradiol was decreased after the onset of treatment (12.4 ± 1.3 vs 9.1 ± 1.2 pg/mL, P = 0.05) and prior to parturition (38.1 ± 8.1 vs 22.3 ± 4.2 pg/mL, P = 0.03). Our hypothesis was supported that fluoxetine treatment alters circulating concentrations of calcium in the peripartum period; however, we surprisingly observed a decrease in estradiol concentrations contrary to reports in in vitro studies.

A Review of Serotonin in the Developing Lung and Neonatal Pulmonary Hypertension

Serotonin (5-HT) is a bioamine that has been implicated in the pathogenesis of pulmonary hypertension (PH). The lung serves as an important site of 5-HT synthesis, uptake, and metabolism with signaling primarily regulated by tryptophan hydroxylase (TPH), the 5-HT transporter (SERT), and numerous unique 5-HT receptors. The 5-HT hypothesis of PH was first proposed in the 1960s and, since that time, preclinical and clinical studies have worked to elucidate the role of 5-HT in adult PH. Over the past several decades, accumulating evidence from both clinical and preclinical studies has suggested that the 5-HT signaling pathway may play an important role in neonatal cardiopulmonary transition and the development of PH in newborns. The expression of TPH, SERT, and the 5-HT receptors is developmentally regulated, with alterations resulting in pulmonary vasoconstriction and pulmonary vascular remodeling. However, much remains unknown about the role of 5-HT in the developing and newborn lung. The purpose of this review is to discuss the implications of 5-HT on fetal and neonatal pulmonary circulation and summarize the existing preclinical and clinical literature on 5-HT in neonatal PH.

Maternal serotonin: implications for the use of selective serotonin reuptake inhibitors during gestation†

Maternal use of antidepressants has increased throughout the last decades; selective serotonin reuptake inhibitors (SSRI) are the most prescribed antidepressants. Despite the widespread use of SSRI by women during reproductive age and pregnant women, an increasing amount of research warns of possible detrimental effects of maternal use of SSRI during pregnancy including low birthweight/small for gestational age and preterm birth. In this review, we revisited the impact of maternal use of SSRI during pregnancy, its impact on serotonin homeostasis in the maternal and fetal circulation and the placenta, and its impact on pregnancy outcomes-particularly intrauterine growth restriction and preterm birth. Maternal use of SSRI increases maternal and fetal serotonin. The increase in maternal circulating serotonin and serotonin signaling likely promotes vasoconstriction of the uterine and placental vascular beds decreasing blood perfusion to the uterus and consequently to the placenta and fetus with potential impact on placental function and fetal development. Several adverse pregnancy outcomes are similar between women, sheep, and rodents (decreased placental size, decreased birthweight, shorter gestation length/preterm birth, neonatal morbidity, and mortality) highlighting the importance of animal studies to assess the impacts of SSRI. Herein, we address the complex interactions between maternal SSRI use during gestation, circulating serotonin, and the regulation of blood perfusion to the uterus and fetoplacental unit, fetal growth, and pregnancy complications.