Developmental toxicity and programming alterations of multiple organs in offspring induced by medication during pregnancy

Medication during pregnancy is widespread, but there are few reports on its fetal safety. Recent studies suggest that medication during pregnancy can affect fetal morphological and functional development through multiple pathways, multiple organs, and multiple targets. Its mechanisms involve direct ways such as oxidative stress, epigenetic modification, and metabolic activation, and it may also be indirectly caused by placental dysfunction. Further studies have found that medication during pregnancy may also indirectly lead to multi-organ developmental programming, functional homeostasis changes, and susceptibility to related diseases in offspring by inducing fetal intrauterine exposure to too high or too low levels of maternal-derived glucocorticoids. The organ developmental toxicity and programming alterations caused by medication during pregnancy may also have gender differences and multi-generational genetic effects mediated by abnormal epigenetic modification. Combined with the latest research results of our laboratory, this paper reviews the latest research progress on the developmental toxicity and functional programming alterations of multiple organs in offspring induced by medication during pregnancy, which can provide a theoretical and experimental basis for rational medication during pregnancy and effective prevention and treatment of drug-related multiple fetal-originated diseases.

Chiral Transplacental Pharmacokinetics of Fexofenadine: Impact of P-Glycoprotein Inhibitor Fluoxetine Using the Human Placental Perfusion Model

PURPOSE

Fexofenadine is a well-identified in vivo probe substrate of P-glycoprotein (P-gp) and/or organic anion transporting polypeptide (OATP). This work aimed to investigate the transplacental pharmacokinetics of fexofenadine enantiomers with and without the selective P-gp inhibitor fluoxetine.

METHODS

The chiral transplacental pharmacokinetics of fexofenadine-fluoxetine interaction was determined using the ex vivo human placenta perfusion model (n = 4). In the Control period, racemic fexofenadine (75 ng of each enantiomer/ml) was added in the maternal circuit. In the Interaction period, racemic fluoxetine (50 ng of each enantiomer/mL) and racemic fexofenadine (75 ng of each enantiomer/mL) were added to the maternal circulation. In both periods, maternal and fetal perfusate samples were taken over 90 min.

RESULTS

The (S)-(-)- and (R)-(+)-fexofenadine fetal-to-maternal ratio values in Control and Interaction periods were similar (~0.18). The placental transfer rates were similar between (S)-(-)- and (R)-(+)-fexofenadine in both Control (0.0024 vs 0.0019 min^-1) and Interaction (0.0019 vs 0.0021 min^-1) periods. In both Control and Interaction periods, the enantiomeric fexofenadine ratios [R-(+)/S-(-)] were approximately 1.

CONCLUSIONS

Our study showed a low extent, slow rate of non-enantioselective placental transfer of fexofenadine enantiomers, indicating a limited fetal fexofenadine exposure mediated by placental P-gp and/or OATP2B1. The fluoxetine interaction did not affect the non-enantioselective transplacental transfer of fexofenadine. The ex vivo placental perfusion model accurately predicts in vivo placental transfer of fexofenadine enantiomers with remarkably similar values (~0.17), and thus estimates the limited fetal exposure.

Chiral Discrimination of P-glycoprotein in Parturient Women: Effect of Fluoxetine on Maternal-Fetal Fexofenadine Pharmacokinetics

BACKGROUND AND OBJECTIVE

Fluoxetine, antidepressant widely-used during pregnancy, is a selective inhibitor for P-glycoprotein (P-gp). Fexofenadine, an in vivo P-gp probe, is an antihistamine drug for seasonal allergic rhinitis and chronic urticaria treatment during pregnancy and it is available as a racemic mixture. This study evaluated the chiral discrimination of P-gp investigating the effect of fluoxetine on maternal-fetal pharmacokinetics of fexofenadine.

METHODS

Healthy parturient women received either a single oral dose of 60 mg racemic fexofenadine (Control group; n = 8) or a single oral dose of 40 mg racemic fluoxetine 3 h before a single oral dose of 60 mg racemic fexofenadine (Interaction group; n = 8). Maternal blood and urine samples were collected up to 48 h after fexofenadine administration. At delivery, maternal-placental-fetal blood samples were collected.

RESULTS

The maternal pharmacokinetics of fexofenadine was enantioselective (AUC^0-∞_R-(+)/S-(-) ~ 1.5) in both control and interaction groups. Fluoxetine increased AUC^0-∞ (267.7 vs 376.1 ng.h/mL) and decreased oral total clearance (105.1 vs 74.4 L/h) only of S-(-)-fexofenadine, whereas the renal clearance were reduced for both enantiomers, suggesting that the intestinal P-gp-mediated transport of S-(-)-fexofenadine is influenced by fluoxetine to a greater extent that the R-(+)-fexofenadine. However, the transplacental transfer of fexofenadine is low (~16%), non-enantioselective and non-influenced by fluoxetine.

CONCLUSIONS

A single oral dose of 40 mg fluoxetine inhibited the intestinal P-gp mediated transport of S-(-)-fexofenadine to a greater extent than R-(+)-fexofenadine in parturient women. However, the placental P-gp did not discriminate fexofenadine enantiomers and was not inhibited by fluoxetine.

Survival of a dog with accidental colchicine overdose

OBJECTIVE

To describe the treatment and clinical course of a dog accidentally prescribed 10 times the recommended dose of colchicine (0.3 mg/kg/d instead of 0.03 mg/kg/d).

CASE SUMMARY

After glaucoma surgery, a 1-year-old male neutered Pomeranian weighing 6.8 kg was prescribed 1,000 μg colchicine twice a day per os. The dog presented to the emergency department after the first dose with vomiting and was treated as an outpatient. Two colchicine doses later, the dog represented with vomiting, ocular pain, and increased intraocular pressure. The dog's vital signs were normal, and the dog was admitted for rehydration, analgesia, and revision glaucoma surgery the next day. Two hours after revision surgery, the dog developed vomiting and diarrhea. Postoperatively, the dog was hypothermic (36.3°C), persistently hypertensive (227 mm Hg), and bradycardic (60/min). Biochemistry revealed metabolic acidosis and increased hepatic enzyme activities. Mannitol was administered for presumed cerebral edema. Later, the dog developed bradycardia due to second-degree atrioventricular heart block, which responded to atropine. Total hospitalization was 9 days. Treatment included IV fluids, IV lipid emulsion, N-acetylcysteine, activated charcoal, gastroprotectants, antiemetics, opioids, antimicrobials, and barrier nursing due to transient neutropenia.

NEW OR UNIQUE INFORMATION PROVIDED

This is the first report to describe the successful treatment of a dog with colchicine overdose. The systemic effects were presumed to be secondary to colchicine toxicosis rather than diet, infection, or other drug reaction, and may have been compounded by a second anesthetic episode. Gastrointestinal signs, symptoms of cerebral edema, cardiac arrhythmias, and neutropenia were documented. One other report of colchicine overdose in a dog exists, and that patient was euthanized. This report demonstrates that complete recovery with intensive care is possible; however, the prognosis remains guarded.

Establishment of a cell line for assessing drugs as canine P-glycoprotein substrates: proof of principle

P-glycoprotein (P-gp), encoded by the ABCB1 (MDR1) gene, dramatically impacts drug disposition. P-gp is expressed in the intestines, biliary canaliculi, renal tubules, and brain capillaries where it functions to efflux substrate drugs. In this capacity, P-gp restricts oral absorption, enhances biliary and renal excretion, and inhibits central nervous system entry of substrate drugs. Many drugs commonly used in veterinary medicine are known substrates for canine P-gp (vincristine, loperamide, ivermectin, others). Because these drugs have a narrow therapeutic index, defective P-gp function can cause serious adverse drug reactions due to enhanced brain penetration and/or decreased clearance. P-gp dysfunction in dogs can be intrinsic (dogs harboring ABCB1-1Δ) or acquired (drug interactions between a P-gp inhibitor and P-gp substrate). New human drug candidates are required to undergo assessment for P-gp interactions according to FDA and EMA regulations to avoid adverse drug reactions and drug-drug interactions. Similar information regarding canine P-gp could prevent adverse drug reactions in dogs. Because differences in P-gp substrates have been documented between species, one should not presume that human or murine P-gp substrates are necessarily canine P-gp substrates. Thus, our goal was to develop a cell line for assessing drugs as canine P-gp substrates.

Insights into the regulation of the MXR response in haemocytes of the Mediterranean mussel (Mytilus galloprovincialis)

This study investigated functional and transcriptional modulation of the Multixenobiotic resistance (MXR) system as a cytoprotective mechanism contributing to the physiological chemoresistance of haemocytes in the Mediterranean mussel. Basal transport activity was assessed using the model substrate rhodamine 123 and specific inhibitors for the MXR-related transporters P-glycoprotein (ABCB mRNA) and Multidrug resistance-related protein (ABCC mRNA). Results showed that MXR activity in mussel haemocytes was mainly supported by the Mrp-mediated efflux. In agreement, ABCC was expressed at higher levels than ABCB. Activation of the cyclic-AMP (cAMP) dependent protein kinase A (PKA) resulted in increased rhodamine efflux, which was counteracted by the selective PKA inhibitor H89. Although serotonin, a physiological modulator of cAMP/PKA signaling and ABCB transcription in haemocytes, did not affect basal MXR transport, the environmental pharmaceuticals fluoxetine, propranolol, and carbamazepine, which interact in different ways with the adrenergic and serotoninergic pathways, were showed to act as modulators and substrates of MXR-related transporters and to affect cell viability. While the increased MXR activity may have lowered the cytotoxic effects of propranolol and carbamazepine, the lack of MXR efflux induction by fluoxetine may play a role in the observed cytotoxicity of the compound.

Danio rerio embryos on Prozac - Effects on the detoxification mechanism and embryo development

In the past decade the presence of psychopharmaceuticals, including fluoxetine (FLU), in the aquatic environment has been associated with the increasing trend in human consumption of these substances. Aquatic organisms are usually exposed to chronic low doses and, therefore, risk assessments should evaluate the effects of these compounds in non-target organisms. Teleost fish possess an array of active defence mechanisms to cope with the deleterious effects of xenobiotics. These include ABC transporters, phase I and II of cellular detoxification and oxidative stress enzymes. Hence, the present study aimed at characterising the effect of FLU on embryo development of the model teleost zebrafish (Danio rerio) concomitantly with changes in the detoxification mechanisms during early developmental phases. Embryos were exposed to different concentrations of FLU (0.0015, 0.05, 0.1, 0.5 and 0.8μM) for 80hours post fertilization. Development was screened and the impact in the transcription of key genes, i.e., abcb4, abcc1, abcc2, abcg2, cyp1a, cyp3a65, gst, sod, cat, ahr, pxr, pparα, pparβ, pparγ, rxraa, rxrab, rxrbb, rxrga, rxrgb, raraa, rarab, rarga evaluated. In addition, accumulation assays were performed to measure the activity of ABC proteins and antioxidant enzymes (CAT and Cu/ZnSOD) after exposure to FLU. Embryo development was disrupted at the lowest FLU concentration tested (0.0015μM), which is in the range of concentrations found in WWTP effluents. Embryos exposed to higher concentrations of FLU decreased Cu/Zn SOD, and increased CAT (0.0015 and 0.5μM) enzymatic activity. Exposure to higher concentrations of FLU decreased the expression of most genes belonging to the detoxification system and upregulated cat at 0.0015μM of FLU. Most of the tested concentrations downregulated pparα, pparβ, pparγ, and raraa, rxraa, rxrab, rxrbb rxrgb and ahr gene expression while pxr was significantly up regulated at all tested concentrations. In conclusion, this study shows that FLU can impact zebrafish embryo development, at concentrations found in effluents of WWTPs, concomitantly with changes in antioxidant enzymes, and the transcription of key genes involved in detoxification and development. These finding raises additional concerns supporting the need to monitor the presence of this compound in aquatic reservoirs.