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

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

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

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

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

Data mining analyses for precision medicine in acromegaly: a proof of concept

Predicting which acromegaly patients could benefit from somatostatin receptor ligands (SRL) is a must for personalized medicine. Although many biomarkers linked to SRL response have been identified, there is no consensus criterion on how to assign this pharmacologic treatment according to biomarker levels. Our aim is to provide better predictive tools for an accurate acromegaly patient stratification regarding the ability to respond to SRL. We took advantage of a multicenter study of 71 acromegaly patients and we used advanced mathematical modelling to predict SRL response combining molecular and clinical information. Different models of patient stratification were obtained, with a much higher accuracy when the studied cohort is fragmented according to relevant clinical characteristics. Considering all the models, a patient stratification based on the extrasellar growth of the tumor, sex, age and the expression of E-cadherin, GHRL, IN1-GHRL, DRD2, SSTR5 and PEBP1 is proposed, with accuracies that stand between 71 to 95%. In conclusion, the use of data mining could be very useful for implementation of personalized medicine in acromegaly through an interdisciplinary work between computer science, mathematics, biology and medicine. This new methodology opens a door to more precise and personalized medicine for acromegaly patients

Revisiting the usefulness of the short acute octreotide test to predict treatment outcomes in acromegaly

Introduction: We previously described that a short version of the acute octreotide test (sAOT) can predict the response to first-generation somatostatin receptor ligands (SRLs) in patients with acromegaly. We have prospectively reassessed the sAOT in patients from the ACROFAST study using current ultra-sensitive GH assays. We also studied the correlation of sAOT with tumor expression of E-cadherin and somatostatin receptor 2 (SSTR2) .Methods: A total of 47 patients treated with SRLs for 6 months were evaluated with the sAOT at diagnosis and correlated with SRLs' response. Those patients whose IGF1 decreased to = 3SDS, were considered non-responders. The 2 hours GH value (GH2h) after s.c. administration of 100 mcg of octreotide was used to define predictive cutoffs. E-cadherin and SSTR2 immunostaining in somatotropinoma tissue were investigated in 24/47 and 18/47 patients, respectively.Results: In all, 30 patients were responders and 17 were non-responders. GH(2h) was 0.68 (0.25-1.98) ng/mL in responders vs 2.35 (1.59-9.37) ng/mL in non-responders (p<0.001). GH(2h) = 1.4ng/mL showed the highest ability to identify responders (accuracy of 81%, sensitivity of 73.3%, and specificity of 94.1%). GH(2h) = 4.3ng/mL was the best cutoff for non-response prediction (accuracy of 74%, sensitivity of 35.3%, and specificity of 96.7%). Patients with E-cadherin-positive tumors showed a lower GH(2h) than those with E-cadherin-negative tumors [0.9 (0.3-2.1) vs 3.3 (1.5-12.1) ng/mL; p<0.01], and patients with positive E-cadherin presented a higher score of SSTR2 (7.5 +/- 4.2 vs 3.3 +/- 2.1; p=0.01).Conclusion: The sAOT is a good predictor tool for assessing response to SRLs and correlates with tumor E-cadherin and SSTR2 expression. Thus, it can be useful in clinical practice for therapeutic decision-making in patients with acromegaly

Revisiting the usefulness of the short acute octreotide test to predict treatment outcomes in acromegaly

IntroductionWe previously described that a short version of the acute octreotide test (sAOT) can predict the response to first-generation somatostatin receptor ligands (SRLs) in patients with acromegaly. We have prospectively reassessed the sAOT in patients from the ACROFAST study using current ultra-sensitive GH assays. We also studied the correlation of sAOT with tumor expression of E-cadherin and somatostatin receptor 2 (SSTR2) .MethodsA total of 47 patients treated with SRLs for 6 months were evaluated with the sAOT at diagnosis and correlated with SRLs’ response. Those patients whose IGF1 decreased to &lt;3SDS from normal value were considered responders and those whose IGF1 was ≥3SDS, were considered non-responders. The 2 hours GH value (GH2h) after s.c. administration of 100 mcg of octreotide was used to define predictive cutoffs. E-cadherin and SSTR2 immunostaining in somatotropinoma tissue were investigated in 24/47 and 18/47 patients, respectively.ResultsIn all, 30 patients were responders and 17 were non-responders. GH2h was 0.68 (0.25-1.98) ng/mL in responders vs 2.35 (1.59-9.37) ng/mL in non-responders (p&lt;0.001). GH2h = 1.4ng/mL showed the highest ability to identify responders (accuracy of 81%, sensitivity of 73.3%, and specificity of 94.1%). GH2h = 4.3ng/mL was the best cutoff for non-response prediction (accuracy of 74%, sensitivity of 35.3%, and specificity of 96.7%). Patients with E-cadherin-positive tumors showed a lower GH2h than those with E-cadherin-negative tumors [0.9 (0.3-2.1) vs 3.3 (1.5-12.1) ng/mL; p&lt;0.01], and patients with positive E-cadherin presented a higher score of SSTR2 (7.5 ± 4.2 vs 3.3 ± 2.1; p=0.01).ConclusionThe sAOT is a good predictor tool for assessing response to SRLs and correlates with tumor E-cadherin and SSTR2 expression. Thus, it can be useful in clinical practice for therapeutic decision-making in patients with acromegaly