Mechanism-based models in reproductive and developmental toxicology

This chapter discusses the study of the currently available models for testing developmental toxicity (embryotoxicity and teratogenicity). The main alternative models for testing developmental toxicity are described. These models are divided between validated models (whole-embryo culture test (WEC), micromass test (MM) and embryonic stem cell test (EST)) and those that are not currently validated (although have proven scientific validity) as is the case of zebrafish, frog embryo teratogenesis assay (FETAX), in silico models for predicting embryotoxicity, in vitro cellular models different from the EST method, and methods using fragments of embryos. The non-validated alternative models for testing developmental toxicity are also explained here. To date, only three in vitro methods (MM, EST and WEC) have been validated by an international agency (ECVAM) in order to be used for testing the embryotoxicity potential of chemicals, although other models such as FETAX and zebrafish have also proved their validity for this purpose. Methods based on the employment of embryos allow the specific malformation expected after exposure to the chemical to be determined, while methods based on cellular systems are more relevant in order to determine the mechanism underlying the adverse observed effect and still display a wide field for improving their prediction capability

OECD guidelines and validated methods for in vivo testing of reproductive toxicity

This chapter discusses the methods adapted by the OECD and some other protocols, including the general principles of the study, the main aspects of the procedure, the endpoints and the observations, data reporting and criteria for interpreting results, and summarizing the guidelines. OECD 414 provides general information concerning the effects of prenatal exposure on the pregnant test animal and on the developing organism. OECD 415 is designed to provide general information concerning the effects of the tested substance on male and female reproductive performance. OECD 416 test is designed to provide general information concerning the effects of a tested substance on the integrity and performance of the male and female reproductive systems, including gonadal function, the estrus cycle, mating behavior, conception, gestation, parturition, lactation and weaning, and the growth and development of the offspring. The study also provides information about the effects on the first generation (F1) including neonatal morbidity, mortality and preliminary data on prenatal and postnatal developmental toxicity. OECD 421 offers only limited means of detecting postnatal manifestations of prenatal exposure, or effects that may be induced during postnatal exposure. OECD 422 is intended for identification of possible health hazards likely to arise from repeated exposure over a relatively limited period of time. OECD 426 is designed to provide data, including dose–response characterization, on the potential functional and morphological effects on the developing nervous system of the offspring that may arise from exposure in uterus and during early life

Reproductive toxicity: in vivo testing guidelines from OECD

The guidelines for testing the reproductive toxicity in vivo developed and validated by Organisation for Economic Cooperation and Development allow for a systematic and internationally accepted testing and assessment of chemicals. Within reproductive toxicity two main categories of guidelines are usually identified: one dedicated to testing developmental toxicity, starting before the gestation period, while the other guidelines test the reproductive toxicity as a whole, therefore including male and female fertility and development. In this chapter, we summarize the guidelines on in vivo reproductive toxicity, by describing the general principles of the studies, the main aspects of the procedure, the endpoints and the observations, data reporting, and the criteria needed for the interpretation of their results

Chapter 7 - Alternative methods to animal experimentation for testing developmental toxicity

The available alternative methods for testing developmental toxicity comprise either cellular models or whole embryos of rodents, fish, or amphibian. The simplest cellular models consider the use of human or animal embryonic stem cells (embryonic or of induced pluripotency) under differentiation and one of the most widely used endpoints in these methods is the alterations in differentiated beating cardiomyocytes, although determination of other molecular markers is also extended. More complex cellular models consider the use of cocultures or 3D cultures or the so-called organoids. These models mimic the physiological environment in a much better way than the simple monolayer cultures. The use of whole embryos allows the determination of which teratogenic effects are expectable after exposure to developmental toxicants, which is one of the main disadvantages of the cellular methods. The appropriate assessment of chemical safety for development needs of a battery of alternative methods applied. Integrated Approaches to Testing and Assessment (IATA) would allow in the close future to perform safe and reliable assessment of developmental toxicity based on alternative methods

Cell Viability Effects and Antioxidant and Antimicrobial Activities of Tunisian Date Syrup (Rub El Tamer) Polyphenolic Extracts

The aqueous−acetone polyphenolic extract of the traditionally derived date syrup, known as “Rub El Tamer”, was analyzed using RP-HPLC-DAD and ESI-MS. The phenolic content of the extract was 394.53 ± 1.13 mg per 100 g of syrup with caffeoylsinapylquinic acid as the most abundant compound (72.23%). The extract exhibited strong antioxidant activities as evaluated using the ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)), DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) methods. The extract antimicrobial potential against a range of microorganism strains showed that Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus cereus were the most sensitive bacteria with MBC in the range of 0.5−0.05 mg/mL. Furthermore, in the presence of the syrup extract (8.18−131 μg/mL), the Human SH-SY5Y neuroblastoma and the 3T3 fibroblast cell lines showed dissimilar reduction of viability suggesting a higher cytotoxic effect against tumorigenic cells. Our results provide new insights into date syrup characterization which should stimulate further studies of this hot desert resource

Polyphenolic Extract of Barbary-Fig (Opuntia ficus-indica) Syrup: RP–HPLC–ESI–MS Analysis and Determination of Antioxidant, Antimicrobial and Cancer-Cells Cytotoxic Potentials

The traditionally derived syrup of Opuntia ficus-indica fruit is commonly used in homemade confectionery. Herein, the aqueous-acetone extract prepared from the Tunisian O. ficus-indica syrup was investigated. The qualitatively and quantitatively polyphenolic content was analysed using reversed-phase high-performance liquid chromatography–diode array detection (RP-HPLC–DAD) coupled to electrospray ionisation–mass spectrometry (ESI–MS). The extract contained 19.95 ± 2.01 mg phenolics per gram of fresh starting material with isorhamnetin 3-O-robinobioside as the major compound (22.76%). The syrup extract showed strong antioxidant potentials as assessed by both ABTS and DPPH functional methods. It exhibited effective antimicrobial activity, particularly against Staphylococcus aureus and Staphylococcus epidermidis with a minimal bactericide concentration (MBC) of 1.3 mg phenolics/ml. Furthermore, at final concentrations in the range of 41.38–186.25 μg polyphenols/ml, the extract decreased human SH-SY5Y neuroblastoma and 3T3 fibroblast in vitro cell viability in a dose- and time-dependent manner compared to non-treated control cells. The observed effects were significantly (P < 0.05) high against cancer lines. Extract concentrations higher than 106.43 μg/ml reduced cancer cells viability to 50–60% 1–3 h post-treatment. Further in vivo insight studies should emphasise and validate the herein obtained results

Cytotoxic effect against 3T3 fibroblasts cells of saffron floral bio-residues extracts

For every kilogram of saffron spice produced, about 63 kg of floral bio-residues (FB) (tepals, stamens and styles) are thrown away. Extracts of these bio-residues in water (W1), water:HCl (100:1, v/v) (W2), ethanol (E3), ethanol:HCl (100:1, v/v) (E4), dichloromethane (D5) and hexane (H6) were prepared. Their composition in flavonols and anthocyanins, and their effect on cell viability were determined. W1 was the richest in kaempferol 3-sophoroside (30.34 mg/g dry FB) and delphinidin 3,5-diglucoside (15.98 mg/g dry FB). The highest tested concentration (900 μg/ml) of W1, W2, E4, D5 and H6 did not significantly decrease the cell viability. Only E3 at that concentration caused a significant decrease of 38% in the cell viability. Therefore, all extracts studied are not cytotoxic at concentrations lower than 900 μg/ml, and W1 is proposed as the optimal for food applications due to its greater contribution of phenolic compounds

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Chlorpyrifos and its metabolites alter gene expression at non-cytotoxic concentrations in D3 mouse embryonic stem cells under in vitro differentiation: Considerations for embryotoxic risk assessment

The effects of organophosphate insecticide chlorpyrifos (CPF) on development are currently under discussion. CPF and its metabolites, chlorpyrifos-oxon (CPO) and 3,5,6-trichloro-2-pyridinol (TClP), were more cytotoxic for D3 mouse embryonic stem cells than for differentiated fibroblasts 3T3 cells. Exposure to 10 μM CPF and TClP and 100 μM CPO for 12 h significantly altered the in vitro expression of biomarkers of differentiation in D3 cells. Similarly, exposure to 20 μM CPF and 25 μM CPO and TClP for 3 days also altered the expression of the biomarkers in the same model. These exposures caused no significant reduction in D3 viability with mild inhibition of acetylcholinesterase and neuropathy target esterase by CPF and severe inhibition by CPO. We conclude that certain in vivo exposure scenarios are possible, which cause inhibition of acetylcholinesterase but without clinical symptoms that reach high enough systemic CPF concentrations able to alter the expression of genes involved in cellular differentiation with potentially hazard effects on development. Conversely, the risk for embryotoxicity by CPO and TClP was very low because the required exposure would induce severe cholinergic syndrome

International Impact of COVID-19 on the Diagnosis of Heart Disease

Background: The coronavirus disease 2019 (COVID-19) pandemic has adversely affected diagnosis and treatment of noncommunicable diseases. Its effects on delivery of diagnostic care for cardiovascular disease, which remains the leading cause of death worldwide, have not been quantified. Objectives: The study sought to assess COVID-19's impact on global cardiovascular diagnostic procedural volumes and safety practices. Methods: The International Atomic Energy Agency conducted a worldwide survey assessing alterations in cardiovascular procedure volumes and safety practices resulting from COVID-19. Noninvasive and invasive cardiac testing volumes were obtained from participating sites for March and April 2020 and compared with those from March 2019. Availability of personal protective equipment and pandemic-related testing practice changes were ascertained. Results: Surveys were submitted from 909 inpatient and outpatient centers performing cardiac diagnostic procedures, in 108 countries. Procedure volumes decreased 42% from March 2019 to March 2020, and 64% from March 2019 to April 2020. Transthoracic echocardiography decreased by 59%, transesophageal echocardiography 76%, and stress tests 78%, which varied between stress modalities. Coronary angiography (invasive or computed tomography) decreased 55% (p &lt; 0.001 for each procedure). In multivariable regression, significantly greater reduction in procedures occurred for centers in countries with lower gross domestic product. Location in a low-income and lower–middle-income country was associated with an additional 22% reduction in cardiac procedures and less availability of personal protective equipment and telehealth. Conclusions: COVID-19 was associated with a significant and abrupt reduction in cardiovascular diagnostic testing across the globe, especially affecting the world's economically challenged. Further study of cardiovascular outcomes and COVID-19–related changes in care delivery is warranted