Altered activities of CYP1A1 and CYP19A1 enzymes in women using SSRI medication during pregnancy

INTRODUCTION

Selective serotonin reuptake inhibitors (SSRIs) are commonly used medication for the treatment of depression during pregnancy. Their use may affect various biological molecules such as enzymes which regulate placental hormonal production and xenobiotic metabolism. Our aim was to investigate the effect of maternal SSRI use on activities of three placental enzymes.

METHODS

We analyzed activities of xenobiotic metabolism enzymes cytochrome P450 1A1 (CYP1A1), aromatase (CYP19A1), and glutathione-S-transferase (GST) from placental microsomal and cytosolic subcellular fractions. Term placentas were collected from 47 SSRI users and 49 control women participating Kuopio Birth cohort (KuBiCo) during the years 2013-2015. Among SSRI users, escitalopram was the most widely used SSRI medication.

RESULTS

The mean enzyme activities of all studied enzymes were lower in SSRI users compared to controls. A statistically significant difference was observed in the enzyme activities of CYP19A1 (p = 0.001) and CYP1A1 (p = 0.002) between the study groups after adjusting for use of additional medication, gestational diabetes, sex of the newborn and gestational weeks at delivery. SSRI use had no significant effect on placental GST enzyme activity.

DISCUSSION

Our results indicate that SSRI medication alters placental enzyme activities. This may lead disturbances in maternal steroid hormone balance as well as in xenobiotic metabolism and may provide risk for both developing fetus and pregnant women.

A comprehensive review on non-clinical methods to study transfer of medication into breast milk - A contribution from the ConcePTION project

Breastfeeding plays a major role in the health and wellbeing of mother and infant. However, information on the safety of maternal medication during breastfeeding is lacking for most medications. This leads to discontinuation of either breastfeeding or maternal therapy, although many medications are likely to be safe. Since human lactation studies are costly and challenging, validated non-clinical methods would offer an attractive alternative. This review gives an extensive overview of the non-clinical methods (in vitro, in vivo and in silico) to study the transfer of maternal medication into the human breast milk, and subsequent neonatal systemic exposure. Several in vitro models are available, but model characterization, including quantitative medication transport data across the in vitro blood-milk barrier, remains rather limited. Furthermore, animal in vivo models have been used successfully in the past. However, these models don't always mimic human physiology due to species-specific differences. Several efforts have been made to predict medication transfer into the milk based on physicochemical characteristics. However, the role of transporter proteins and several physiological factors (e.g., variable milk lipid content) are not accounted for by these methods. Physiologically-based pharmacokinetic (PBPK) modelling offers a mechanism-oriented strategy with bio-relevance. Recently, lactation PBPK models have been reported for some medications, showing at least the feasibility and value of PBPK modelling to predict transfer of medication into the human milk. However, reliable data as input for PBPK models is often missing. The iterative development of in vitro, animal in vivo and PBPK modelling methods seems to be a promising approach. Human in vitro models will deliver essential data on the transepithelial transport of medication, whereas the combination of animal in vitro and in vivo methods will deliver information to establish accurate in vitro/in vivo extrapolation (IVIVE) algorithms and mechanistic insights. Such a non-clinical platform will be developed and thoroughly evaluated by the Innovative Medicines Initiative ConcePTION.