The chorioallantoic membrane (CAM) can be used as a valuable research tool to examine tumors. The CAM can be used to investigate processes such as migration, invasion, and angiogenesis and to assess novel antitumor drugs. The CAM can be used to establish tumors in a straightforward, rapid, and cost-effective manner via xenotransplantation of cells or tumor tissues with reproducible results; furthermore, the use of the CAM adheres to the three “R” principle, i.e., replace, reduce, and refine. To achieve successful tumor establishment and survival, several technical aspects should be taken into consideration. The complexity and heterogeneity of diseases including neuroblastoma and cancers in general and their impact on human health highlight the importance of preclinical models that help us describe tumor-specific biological processes. These models will not only help in understanding tumor biology, but also allow clinicians to explore therapeutic alternatives that will improve current treatment strategies. In this review, we summarize the technical characteristics as well as the main findings regarding the use of this model to study neuroblastoma for angiogenesis, metastasis, drug sensitivity, and drug resistance.

Despite the extensive information available on the different genetic, epigenetic, and molecular features of cardiogenesis, the origin of congenital heart defects remains unknown. Most genetic and molecular studies have been conducted outside the context of the progressive anatomical and histological changes in the embryonic heart, which is one of the reasons for the limited knowledge of the origins of congenital heart diseases. We integrated the findings of descriptive studies on human embryos and experimental studies on chick, rat, and mouse embryos. This research is based on the new dynamic concept of heart development and the existence of two heart fields. The first field corresponds to the straight heart tube, into which splanchnic mesodermal cells from the second heart field are gradually recruited. The overall aim was to create a new vision for the analysis, diagnosis, and regionalized classification of congenital defects of the heart and great arteries. In addition to highlighting the importance of genetic factors in the development of congenital heart disease, this study provides new insights into the composition of the straight heart tube, the processes of twisting and folding, and the fate of the conus in the development of the right ventricle and its outflow tract. The new vision, based on in vivo labeling and cell tracking and enhanced by models such as gastruloids and organoids, has contributed to a better understanding of important errors in cardiac morphogenesis, which may lead to several congenital heart diseases.

Hyperglycemia during gestation can disrupt fetal heart development and increase postnatal cardiovascular disease risk. It is therefore imperative to identify early biomarkers of hyperglycemia during gestation-induced fetal heart damage and elucidate the underlying molecular pathomechanisms. Clinical investigations of diabetic adults with heart dysfunction and transgenic mouse studies have revealed that overexpression or increased expression of TNNI3K, a heart-specific kinase that binds troponin cardiac I, may contribute to abnormal cardiac remodeling, ventricular hypertrophy, and heart failure. Optimal heart function also depends on the precise organization of contractile and excitable tissues conferred by intercellular occlusive, adherent, and communicating junctions. The current study evaluated changes in embryonic heart development and the expression levels of sarcomeric proteins (troponin I, desmin, and TNNI3K), junctional proteins, glucose transporter-1, and Ki-67 under fetal hyperglycemia. Stage 22HH Gallus domesticus embryos were randomly divided into two groups: a hyperglycemia (HG) group, in which individual embryos were injected with 30 mmol/L glucose solution every 24 h for 10 days, and a no-treatment (NT) control group, in which individual embryos were injected with physiological saline every 24 h for 10 days (stage 36HH). Embryonic blood glucose, height, and weight, as well as heart size, were measured periodically during treatment, followed by histopathological analysis and estimation of sarcomeric and junctional protein expression by western blotting and immunostaining. Hyperglycemic embryos demonstrated delayed heart maturation, with histopathological analysis revealing reduced left and right ventricular wall thickness (−39% and −35% vs. NT). Immunoexpression levels of TNNI3K and troponin 1 increased (by 37% and 39%, respectively), and desmin immunofluorescence reduced (by 23%). Embryo-fetal hyperglycemia may trigger an increase in the expression levels of TNNI3K and troponin I, as well as dysfunction of occlusive and adherent junctions, ultimately inducing abnormal cardiac remodeling.

Learning alterations in the child population may be linked to gestational diabetes as a causal factor, though this remains an open and highly controversial question. In that sense, it has been reported that maternal hyperglycemia generates a threatening condition that affects hippocampal development in offspring. The pyramidal cells of the CA3 subfield, a key structure in learning and memory processes, are particularly important in cognitive deficiencies. We evaluate the effect of the hyperglycemic intrauterine environment on hippocampal histomorphometry in offspring, correlating it with spatial learning and memory, as well as the morphology of dendrites and spines in 30-day-old pups (P30). The maternal hyperglycemia affected the body weight, height, and brain size of fetuses at 21 days of gestation (F21), newborn pups (P0) and P30 pups from diabetic rats, which were smaller compared to the control group. Consequently, this resulted in a decrease in hippocampal size, lower neuronal density and cytoarchitectural disorganization in the CA3 region of the hippocampus in the offspring at the three ages studied. The behavioral tests performed showed a direct relationship between morpho-histological alterations and deficiencies in learning and memory, as well as alterations in the morphology of the dendrites and spines. Therefore, knowing the harmful effects caused by gestational diabetes can be of great help to establish therapeutic and educational strategies that can help to improve learning and memory in children.

Neural crest cells (NCCs) play a significant role in the development of ventricular outflow tracts (OFTs), and cardiac neural crest cells (cNCCs) are involved in the development of the embryonic conus, suggesting that these cell lineages may be a teratogenic target for the development of cardiopathies in offspring conceived under a hyperglycemic environment. We evaluate the effect of the hyperglycemic intrauterine environment on the morphological and anatomical changes in the conal ridges along with the alterations in the spatiotemporal expression of AP2α in offspring hearts at 13, 15, and 17 DPC. The anatomical and histological analysis of the hearts in the experimental group presented smaller dimensions compared to the control group in the offspring at the three ages studied. Consequently, this resulted in a hyperglycemic environment that altered the immunostaining of AP2α in the hearts of the offspring at the three ages studied. Thus, the hyperglycemic intrauterine environment in offspring caused important morphological alterations in the development of conal ridges and promoted the generation of conotruncal heart defects in which the double outlet of the right ventricle, the atrioventricular (AV) canal, predominated. Therefore, knowing that exposing the offspring to more glucose potentially can lead to complications during organogenesis of the circulatory and central nervous systems.

Cervical cancer (CC) remains a significant public health problem. Despite the availability of standard treatment strategies, chemotherapy-resistant tumors persist, highlighting the need to explore new therapeutic approaches or adjuvant strategies. This underscores the importance of preclinical in vivo models. Conventional models, such as murine xenografts, patient-derived xenografts (PDXs), and patient-derived organoids (PDOs), provide valuable biological relevance but are often time-consuming, costly, and resource-intensive. In this context, the chick embryo chorioallantoic membrane (CAM) assay represents a rapid, low-cost, and technically accessible in vivo platform. The CAM is a non-innervated, highly vascularized extraembryonic structure that provides a suitable environment for tumor generation from xenografts. However, despite the broad use of the CAM assay for tumor xenografts, standardized and comparative methodological optimizations specifically addressing technical variables for cervical cancer tumor induction remain limited. Therefore, the aim of this study was to optimize the CAM assay for tumor generation using the HeLa and SiHa cell lines. The generated tumors are vascularized and exhibit Ki-67 expression. The CAM assay is an excellent short-term exploratory model based on developing chicken embryos for studying the developmental biology of cervical tumors, which would accelerate the preclinical investigation of new therapeutic molecules.