The teratogenic effects of imatinib mesylate on rat fetuses

Human ABL1 deficiency syndrome (HADS) is a recognizable syndrome distinct from ABL1-related congenital heart defects and skeletal malformations syndrome

Germline gain of function variants in the oncogene ABL1 cause congenital heart defects and skeletal malformations (CHDSKM) syndrome. Whether a corresponding ABL1 deficiency disorder exists in humans remains unknown although developmental defects in mice deficient for Abl1 support this notion. Here, we describe two multiplex consanguineous families, each segregating a different homozygous likely loss of function variant in ABL1. The associated phenotype is multiple congenital malformations and distinctive facial dysmorphism that are opposite in many ways to CHDSKM. We suggest that a tight balance of ABL1 activity is required during embryonic development and that both germline gain of function and loss of function variants result in distinctively different allelic congenital malformation disorders.

Pregnancy and long-term outcomes of female patients with chronic myeloid leukemia on tyrosine kinase inhibitors who experienced unplanned pregnancies

PURPOSE

Despite the general recommendation to avoid Tyrosine Kinase Inhibitors (TKIs) for Chronic Myeloid Leukemia (CML) during pregnancy, unplanned pregnancies still occur, particularly among female patients residing in low- and middle-income countries (LMICs). We aimed to investigate the outcomes of pregnancy, foetal development, and disease progression among female CML patients in chronic phase (CML-CP) undergoing TKI therapy who encountered unplanned pregnancies in a tertiary care hospital in northern India.

METHODS

We conducted a retrospective analysis of all pregnancies in female CML-CP between January 2002 and December 2022 at our hospital. Patients were included if they had a confirmed diagnosis of CML-CP, were receiving TKI therapy during conception, and had available medical records. We analysed the data on pregnancy outcomes, foetal development, and disease progression through a review of medical records.

RESULTS

We identified 36 pregnancies in female CML-CP patients on TKI therapy during the study period, with 33 (91.7%) being unplanned. Sixteen pregnancies (48.5%) were conceived at less than major molecular remission (MMR) status. Twelve pregnancies (36.4%) were electively terminated, 4 (12.1%) had miscarriages, and, 17 (51.5%) pregnancies resulted in childbirth. Out of the 17 childbirths, 10 were full-term deliveries, and 7 were preterm deliveries. Twin pregnancies had a high incidence (18.2%). Among the 21 pregnancies that were not electively terminated, TKI was stopped at the first pregnancy detection in 14 pregnancies, while imatinib was continued throughout 7 pregnancies. Patients who discontinued TKI had a higher but statistically non-significant incidence of adverse pregnancy outcomes compared to those who continued imatinib throughout pregnancy (64.2% vs. 28.6%, p = 0.18). Additionally, the risk of long-term disease progression among patients who discontinued TKI during pregnancy and those who continued imatinib throughout pregnancy was 21.4% and 16.7% (p = 0.9), respectively. The risk of long-term disease progression was significantly increased in those persistently at less than MMR pre- and post-gestation (p = 0.0002).

CONCLUSION

Our findings suggest that continuing imatinib therapy during pregnancy, may be a reasonable option for CML patients residing in low- and middle-income countries to reduce the risk of disease progression and adverse pregnancy outcomes. Patients persistently at less than MMR levels pre- and post-gestation should be closely monitored for the risk of long-term disease progression. Further studies with larger sample sizes are needed to confirm these results.

Diagnosis and management of high risk gastrointestinal stromal tumor in first trimester pregnancy: A case report and review of the literature

Objective

There are less than 20 reported cases of gastrointestinal stromal tumors in pregnancy. Of these reported cases, there are only two that detail GIST in the first trimester. We report our experience with the third known GIST diagnosis in the first trimester of pregnancy. Notably, our case report highlights the earliest known gestational age at time of GIST diagnosis.

Methods

We conducted a literature review of GIST diagnosis in pregnancy via PUBMED, using a combination of the following terms: (pregnancy or gestation) and (GIST). We utilized Epic for chart review of our patient's case report.

Results

A 24 year old G3P1011 presented to the Emergency Department at 4w6d by last menstrual period (LMP) with worsening abdominal cramping, bloating, and associated nausea. Physical exam revealed a large, mobile, nontender mass palpated in the right lower abdomen. Transvagianl ultrasound noted the presence of a large pelvic mass of unknown etiology. Pelvic magnetic resonance imaging (MRI) was obtained for further characterization, revealing a 7.3× 12.4 × 12.2 cm mass with multiple fluid levels, centered in the anterior mesentery. Exploratory laparotomy was performed with en bloc resection of small bowel and pelvic mass, with pathology demonstrating a 12.8 cm spindle cell neoplasm compatible with GIST and notable for a mitotic rate of 40 mitoses/50 high power field (HPF). Next generation sequencing (NGS) was pursued in order to predict tumor responsiveness to Imatinib, which revealed a mutation at KIT exon 11, suggesting a response to tyrosine kinase inhibitor therapy. The patient's multidisciplinary treatment team, consisting of medical oncologists, surgical oncologists, and maternal fetal medicine specialists, made the recommendation for adjuvant Imatinib therapy. The patient was offered termination of pregnancy with immediate initiation of Imatinib, as well as continuation of pregnancy with either immediate or delayed treatment. Interdisciplinary counseling focused on both the maternal and fetal implications of each proposed management plan. She ultimately elected termination of pregnancy, and underwent an uncomplicated dilation and evacuation.

Conclusions

GIST diagnosis in pregnancy is exceedingly rare. Patients with high-grade disease encounter a multitude of decision-making dilemmas, often with competing maternal and fetal interests. As additional cases of GIST in pregnancy are added to the literature, clinicians will be able to implement evidence-based options counseling for their patients. Shared decision-making is contingent upon patient understanding of diagnosis, risk of recurrence, available treatment options, and the treatment-related implications on maternal and fetal outcomes. A multidisciplinary approach is crucial for optimization of patient-centered care.

Safe and Effective Use of Imatinib to Treat Philadelphia Chromosome Positive Acute Lymphoblastic Leukemia During Pregnancy

Philadelphia chromosome positive (Ph+) B cell acute lymphoblastic leukemia (ALL) is extremely rare in pregnancy. Although the use of tyrosine kinase inhibitors (TKIs) has significantly improved outcomes of patients with Ph+ ALL, its use during pregnancy is not recommended due to the risk of fetal malformations. There are limited data on the use of TKIs during pregnancy and its long-term effects on the fetus. Within this context, we present a case of a 25-year-old woman diagnosed with Ph+ ALL during the third trimester and the safe and effective use of imatinib as treatment after failure of conventional chemotherapy.

Outcomes of the Pregnancies with Chronic Myeloid Leukemia in the Tyrosine Kinase Inhibitor Era and Literature Review

Chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasm (MPN) that accounts for 10% of pregnancy-associated leukemias. The Philadelphia chromosome balanced translocation, t (9:22) (q34; q11.2), is the classic mutation seen in CML. The BCR-ABL oncoprotein encoded by this mutation is a constitutively active tyrosine kinase. Tyrosine kinase inhibitor (TKI) therapy is considered a first-line treatment for CML. However, the literature has revealed risks of teratogenicity with TKI therapy during pregnancy. Understanding the risks and benefits of TKI therapy and alternative therapies such as interferon-alpha (IFN-α) will help clinicians and pregnant patients develop a personalized CML treatment plan. This manuscript presents a case series detailing the management of five pregnancies in two pregnant patients with CML and a literature review of CML management in pregnancy.

Integrated fibroblast growth factor signal disruptions in human iPS cells for prediction of teratogenic toxicity of chemicals

The number of man-made chemicals has increased rapidly in recent decades, with certain chemicals potentially causing malformations in fetuses. Although the toxicities of chemicals have been tested in animals, chemicals that are not teratogenic in rodents can cause severe malformations in humans, owing to the differences in the susceptibility to the teratogenicity of chemicals among species. One possible cause of such species differences, other than pharmacokinetics, could be the difference in sensitivity to such chemicals at the cellular level. Therefore, a human cell-based high-throughput assay system is needed for detecting potential teratogenic chemicals. In this study, we proposed a signal reporter assay using human induced pluripotent stem cells (iPSCs). Because developmental processes are governed by highly intricate and precisely programmed signaling pathways, external chemical-induced disruption of these pathways often triggers developmental toxicities. The reporter assay using hiPSCs was used to detect changes in the fibroblast growth factor (FGF) signaling pathway, a pathway essential for limb morphogenesis. The method was based on monitoring and time-accumulation of the signal disruption over time, rather than the classical endpoint detection of the signal disruption. This approach was useful for detecting signal disruptions caused by the malformation chemicals listed in the ICH S5 guideline, including thalidomide. The human iPSC-based signal disruption assay could be a promising tool for the initial screening of developmental toxicants.

Developmental toxicity of lead in rats after gestational exposure and the protective role of taurine

The present study was conducted to investigate the potential adverse effect of Pb on pregnant Sprague-Dawley rats and their fetuses after maternal exposure, on gestational days (GD) 7-16. The possible protective role of taurine (TA), administered throughout the gestation period (GD 1-20) against Pb toxicity, was also evaluated. Pregnant rats were divided into four groups: Group 1 (control) was given distilled water; Group 2 was exposed to Pb (250 ppm) in drinking water (GD 7-16), whereas Group 3 received TA (50 mg/kg/day) by oral gavage (GD 1-20); Group 4 was exposed to Pb (GD 7-16), whereas pretreated with TA from GD 1 till the end of the gestation period. After termination on GD 20, maternal and embryo-fetal outcomes were evaluated. Blood samples were collected for hematological and biochemical parameters assessment. The results showed that, Pb induced a significant reduction in the maternal body weight, weight gain, uterine and placental weight, in addition to a high incidence of abortion and fetal resorption. Meanwhile, fetuses demonstrated decreased body weight and length, with a high rate of mortality as well as external and skeletal abnormalities. Additionally, Pb induced severe hematological and biochemical alterations in both dams and fetuses. The toxicity of Pb was further emphasized by placental histopathological examination and hepatic DNA fragmentation. Pretreatment with TA greatly attenuated the impact of Pb on both maternal and fetal parameters. Moreover, TA alleviated the incidence of placental damage and hepatic DNA fragmentation. The results highlight the potential prophylaxis role of TA against maternal and developmental Pb toxicity.

Chemical-Induced Cleft Palate Is Caused and Rescued by Pharmacological Modulation of the Canonical Wnt Signaling Pathway in a Zebrafish Model

Cleft palate is one of the most frequent birth defects worldwide. It causes severe problems regarding eating and speaking and requires long-term treatment. Effective prenatal treatment would contribute to reducing the risk of cleft palate. The canonical Wnt signaling pathway is critically involved in palatogenesis, and genetic or chemical disturbance of this signaling pathway leads to cleft palate. Presently, preventative treatment for cleft palate during prenatal development has limited efficacy, but we expect that zebrafish will provide a useful high-throughput chemical screening model for effective prevention. To achieve this, the zebrafish model should recapitulate cleft palate development and its rescue by chemical modulation of the Wnt pathway. Here, we provide proof of concept for a zebrafish chemical screening model. Zebrafish embryos were treated with 12 chemical reagents known to induce cleft palate in mammals, and all 12 chemicals induced cleft palate characterized by decreased proliferation and increased apoptosis of palatal cells. The cleft phenotype was enhanced by combinatorial treatment with Wnt inhibitor and teratogens. Furthermore, the expression of tcf7 and lef1 as a readout of the pathway was decreased. Conversely, cleft palate was prevented by Wnt agonist and the cellular defects were also prevented. In conclusion, we provide evidence that chemical-induced cleft palate is caused by inhibition of the canonical Wnt pathway. Our results indicate that this zebrafish model is promising for chemical screening for prevention of cleft palate as well as modulation of the Wnt pathway as a therapeutic target.

The effect of imatinib administered in the prenatal period on testis development in rats

BACKGROUND

The purpose of this study was to examine the effects of exposure to imatinib in the prenatal period on testis development in rats.

METHODS

Although all the study groups received intraperitoneal imatinib on prenatal days 1-8, no pregnancy occurred in the Imatinib-80 group. Immunohistochemical analysis, TUNEL, c-kit and PDGF staining revealed no difference between the groups in terms of positivity scoring.

RESULTS

A significant decrease was detected in total sperm counts in the Imatinib-20 group compared to the control group, but the sperm count was higher in the Imatinib-60 group than in the Imatinib-20 group. At biochemical measurements, the drug increased oxidative stress in the testis and serum in the Imatinib-20 group, but caused a decrease in tissue in the Imatinib-60 group. Thiol measurements revealed a decrease in the testis and serum in the Imatinib-60 group, while an increase in serum measurements was observed in the Imatinib-40 group. Analysis revealed no difference between the groups in terms of protamine and histone gene expression levels in testis tissue exposed to imatinib.

CONCLUSION

Our findings show that prenatal exposure to imatinib can lead to histopathological and biochemical changes in testis tissue, but that no adverse effect occurs in nuclear maturation of germ cells during spermiogenesis.

Morphometric analysis of developing zebrafish embryos allows predicting teratogenicity modes of action in higher vertebrates

The early identification of teratogens in humans and animals is mandatory for drug discovery and development. Zebrafish has emerged as an alternative model to traditional preclinical models for predicting teratogenicity and other potential chemical-induced toxicity hazards. To prove its predictivity, we exposed zebrafish embryos from 0 to 96 h post fertilization to a battery of 31 compounds classified as teratogens or non-teratogens in mammals. The teratogenicity score was based on the measurement of 16 phenotypical parameters, namely heart edema, pigmentation, body length, eye size, yolk size, yolk sac edema, otic vesicle defects, otoliths defects, body axis defects, developmental delay, tail bending, scoliosis, lateral fins absence, hatching ratio, lower jaw malformations and tissue necrosis. Among the 31 compounds, 20 were detected as teratogens and 11 as non-teratogens, resulting in 94.44 % sensitivity, 90.91 % specificity and 87.10 % accuracy compared to rodents. These percentages decreased slightly when referred to humans, with 87.50 % sensitivity, 81.82 % specificity and 74.19 % accuracy, but allowed an increase in the prediction levels reported by rodents for the same compounds. Positive compounds showed a high correlation among teratogenic parameters, pointing out at general developmental delay as major cause to explain the physiological/morphological malformations. A more detailed analysis based on deviations from main trends revealed potential specific modes of action for some compounds such as retinoic acid, DEAB, ochratoxin A, haloperidol, warfarin, valproic acid, acetaminophen, dasatinib, imatinib, dexamethasone, 6-aminonicotinamide and bisphenol A. The high degree of predictivity and the possibility of applying mechanistic approaches makes zebrafish a powerful model for screening teratogenicity.

Chemical-induced craniofacial anomalies caused by disruption of neural crest cell development in a zebrafish model

Background

Craniofacial anomalies are among the most frequent birth defects worldwide, and are thought to be caused by gene‐environment interactions. Genetically manipulated zebrafish simulate human diseases and provide great advantages for investigating the etiology and pathology of craniofacial anomalies. Although substantial advances have been made in understanding genetic factors causing craniofacial disorders, limited information about the etiology by which environmental factors, such as teratogens, induce craniofacial anomalies is available in zebrafish.

Results

Zebrafish embryos displayed craniofacial malformations after teratogen treatments. Further observations revealed characteristic disruption of chondrocyte number, shape and stacking. These findings suggested aberrant development of cranial neural crest (CNC) cells, which was confirmed by gene expression analysis of the CNC. Notably, these observations suggested conserved etiological pathways between zebrafish and mammals including human. Furthermore, several of these chemicals caused malformations of the eyes, otic vesicle, and/or heart, representing a phenocopy of neurocristopathy, and these chemicals altered the expression levels of the responsible genes.

Conclusions

Our results demonstrate that chemical‐induced craniofacial malformation is caused by aberrant development of neural crest. This study indicates that zebrafish provide a platform for investigating contributions of environmental factors as causative agents of craniofacial anomalies and neurocristopathy.

Imatinib treatments have long-term impact on placentation and embryo survival

Imatinib is an oral chemotherapeutic used primarily to treat chronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GIST). The potential effects of cancer treatments on a patient’s future fertility  are a major concern affecting the quality of life for cancer survivors. The effects of imatinib on future fertility are unknown. It is teratogenic. Therefore, patients are advised to stop treatment before pregnancy. Unfortunately, CML and GIST have high rates of recurrence in the absence of the drug, therefore halting imatinib during pregnancy endangers the mother. Possible long-term (post-treatment) effects of imatinib on reproduction have not been studied. We have used a mouse model to examine the effects of imatinib on the placenta and implantation after long-term imatinib exposure. We found significant changes in epigenetic markers of key imprinted genes in the placenta. There was a significant decrease in the labyrinth zone and vasculature of the placenta, which could impact fetal growth later in pregnancy. These effects on placental growth occurred even when imatinib was stopped prior to pregnancy. These results indicate potential long-term effects of imatinib on pregnancy and implantation. A prolonged wash-out period prior to pregnancy or extra monitoring for possible placental insufficiency may be advisable.

Teratogenic effects of five anticancer drugs on Xenopus laevis embryos

In recent years, the environmental presence of pharmaceuticals - including anticancer drugs - is an emerging issue. Because of the lack of appropriate critical studies about anticancer drug effects in frogs, the aim of the present study was to investigate lethal and teratogenic effects of five anticancer drugs widely used in large quantities, i.e. 5-flourouracil, capecitabine, cisplatin, etoposide, and imatinib, in the embryos of the South African clawed frog, Xenopus laevis, using FETAX - Frog Embryo Teratogenesis Assay in Xenopus. None of the studied anticancer drugs induced statistically significant mortality within the concentrations tested (0.01-50mg/L, depending on the studied compound), and no growth inhibition of embryos after a 96-h exposure was observed. Except for cisplatin, the other pharmaceuticals induced an increase of developmental malformations such as abdominal edema, axial flexure, head, eyes, gut and heart malformations with statistically significant effects observed at the highest concentrations tested (50mg/L for 5-flourouracil; 30mg/L for etoposide and 20mg/L for capecitabine and imatinib). The results indicate that anticancer drugs can affect embryogenesis mechanisms.

Safe handling of oral antineoplastic medications: Focus on targeted therapeutics in the home setting

Introduction With the growing number of oral targeted therapies being approved for use in cancer therapy, the potential for long-term administration of these drugs to cancer patients is expanding. The use of these drugs in the home setting has the potential to expose family members and caregivers to them either through direct contact with the drugs or indirectly by exposure to the parent compounds and/or their active metabolites in contaminated patients' waste. Methods A systematic literature review was performed and the known adverse health effect of 32 oral targeted therapeutics is summarized. In particular, the carcinogenicity, genotoxicity, and embryo-fetal toxicity, along with the route of excretion were evaluated. Results Carcinogenicity testing has not been performed on most of the oral targeted therapeutics and the genotoxicity data are mixed. However, the majority of these drugs exhibit adverse reproductive effects, some of which are severe. Currently, available data does not permit the possibility of a health hazard from inappropriate handling of drugs and contaminated patients waste to be ignored, especially in a long-term home setting. Further research is needed to understand these issues. Conclusions With the expanding use of targeted therapies in the home setting, family members and caregivers, especially those of reproductive risk age, are, potentially at risk. Overall basic education and related precautions should be taken to protect family members and caregivers from indirect or direct exposure from these drugs. Further investigations and discussion on this subject are warranted.