Chick Chorioallantoic Membrane Model Research Articles

The CAM Model—Q&A with Experts

The chick chorioallantoic membrane (CAM), as an extraembryonic tissue layer generated by the fusion of the chorion with the vascularized allantoic membrane, is easily accessible for manipulation. Indeed, grafting tumor cells on the CAM lets xenografts/ovografts develop in a few days for further investigations. Thus, the CAM model represents an alternative test system that is a simple, fast, and low-cost tool to study tumor growth, drug response, or angiogenesis in vivo. Recently, a new era for the CAM model in immune-oncology-based drug discovery has been opened up. Although there are many advantages offering extraordinary and unique applications in cancer research, it has also disadvantages and limitations. This review will discuss the pros and cons with experts in the field.

Interventional effect of processing temperature on anti-angiogenesis of Coptis chinensis and screening of active components by UPLC-MS/MS on quail chick chorioallantoic membrane model

Ethnopharmacological relevanceCoptis chinensis Franch. (CC), as a commonly used heat-clearing and toxin-resolving traditional Chinese herbal medicine, has gained increased attention for its anti-tumor activity. However, little is known about the anti-tumor angiogenesis effect of CC and its possible bioactive components. Also, it has been shown that temperature affects the quality of CC, albeit whether and how it affects the anti-angiogenic activity of CC is currently unknown. Aim of the studyTo determine the processing temperatures (40, 60, 80, 120, 140, 150, 160 and 200 °C) at which CC has the strongest anti-angiogenic effect and speculate the possible bioactive components. Materials and methodsThe q-CAM model was constructed to explore the anti-angiogenesis agents of CC. The angiogenesis inhibition effects of CC samples at different processing temperatures and its seven alkaloids were determined based on morphological observation and vascular area proportion analysis. UPLC-MS/MS was employed to screen the potent active components of CC on anti-angiogenesis. ResultsAll the intervention by CC at different processing temperatures and its seven alkaloids could inhibit angiogenesis on q-CAM vessels, as evidenced by a poor vasular development in morphological observation and a low vascular area proportion in vascular quantitative analysis, most evident in CC processed at 40 °C and palmatine. LC-MS revealed that palmatine displayed strongest inhibitory effect on q-CAM vessels with a high absorption due to its stable structure. And the maternal nucleus transformation phenomenon of CC alkaloids was found in the quail embryo metabolism. ConclusionsThe q-CAM models in conjunction with the UPLC-MS/MS technique could be a useful tool for assessing tumor angiogenesis and screening tumor-targeted medicines. Processing temperature can affect the anti-angiogenesis effect of CC because of its function on the content of alkaloids, and palmatine can be considered as a prospective anti-angiogenic drug.

Effects of second-generation H1-antihistamine drugs on angiogenesis in in vivo chick chorioallantoic membrane model

Background Literature on the effects of second-generation H1-antihistamines on angiogenesis is limited. Objectives To investigate the effects of cetirizine, desloratadine, and rupatadine (second-generation H1-antihistamines commonly used in dermatology clinics) on angiogenesis in an in vivo chick chorioallantoic membrane (CAM) model. Methods The study was approved by the local ethics committee on animal experimentation. Forty fertilized specific pathogen free eggs were incubated and kept under appropriate temperature and humidity control. Drug solutions were prepared in identical concentrations by dissolving powders in phosphate-buffered saline (PBS). On the third day of the incubation, a small window was opened on the CAM and 0.1 mL desloratadine (1.5 μg/0.1 mL) in the first group, 0.1 mL cetirizine (1.5 μg/0.1 mL) in the second group, 0.1 mL rupatadine in the third group (1.5 μg/0.1 mL), and PBS (0.1 mL) in the fourth group were administered by injection. On the eighth day of incubation, the vascular structures of the CAMs were macroscopically examined and standard digital photographs were taken. The digital images were analyzed and data including mean vessel density, thickness, and number were compared between groups. p < 0.05 was considered statistically significant. Results Vessel densities were similar in the desloratadine, cetirizine, and control groups, whereas they were significantly less in the rupatadine group (p = 0.01). Furthermore, the rupatadine group had significantly lower vessel thickness and number compared with the other groups (p < 0.05 for both). Conclusions Rupatadine showed anti-angiogenic effects in the chick CAM model, compared with desloratadine and cetirizine. The anti-angiogenic effect of rupatadine could be due to its platelet-activating factor (PAF) receptor inhibition. Thus, rupatadine could be a treatment agent in pathological processes in which angiogenesis is responsible. Further studies with larger series are needed to clarify this potential.

Longitudinal bioluminescence imaging to monitor breast tumor growth and treatment response using the chick chorioallantoic membrane model

The development of successful treatment regimens for breast cancer requires strong pre-clinical data generated in physiologically relevant pre-clinical models. Here we report the development of the chick embryo chorioallantoic membrane (CAM) model to study tumor growth and angiogenesis using breast cancer cell lines. MDA-MB-231 and MCF7 tumor cell lines were engrafted onto the chick embryo CAM to study tumor growth and treatment response. Tumor growth was evaluated through bioluminescence imaging and a significant increase in tumor size and vascularization was found over a 9-day period. We then evaluated the impact of anti-angiogenic drugs, axitinib and bevacizumab, on tumor growth and angiogenesis. Drug treatment significantly reduced tumor vascularization and size. Overall, our findings demonstrate that the chick embryo CAM is a clinically relevant model to monitor therapeutic response in breast cancer and can be used as a platform for drug screening to evaluate not only gross changes in tumor burden but physiological processes such as angiogenesis.

Establishment of a ccRCC patient-derived chick chorioallantoic membrane model for drug testing.

Clear cell renal cell carcinoma (ccRCC) is an aggressive subtype of renal cell carcinoma accounting for the majority of deaths in kidney cancer patients. Advanced ccRCC has a high mortality rate as most patients progress and develop resistance to currently approved targeted therapies, highlighting the ongoing need for adequate drug testing models to develop novel therapies. Current animal models are expensive and time-consuming. In this study, we investigated the use of the chick chorioallantoic membrane (CAM), a rapid and cost-effective model, as a complementary drug testing model for ccRCC. Our results indicated that tumor samples from ccRCC patients can be successfully cultivated on the chick chorioallantoic membrane (CAM) within 7 days while retaining their histopathological characteristics. Furthermore, treatment of ccRCC xenografts with sunitinib, a tyrosine kinase inhibitor used for the treatment of metastatic RCC, allowed us to evaluate differential responses of individual patients. Our results indicate that the CAM model is a complementary in vivo model that allows for rapid and cost-effective evaluation of ccRCC patient response to drug therapy. Therefore, this model has the potential to become a useful platform for preclinical evaluation of new targeted therapies for the treatment of ccRCC.

Application of Laser Speckle Contrast Imaging (LSCI) for the Angiogenesis Measurement of Tumors in the Chorioallantoic Membrane (CAM) Model.

Tumor angiogenesis is one essential aspect for the growth and metastasis of cancer cells, which means that adequate in vivo angiogenesis models are of utmost importance for the investigation of such diseases. The chick chorioallantoic membrane (CAM) model is one established method for this purpose and has already been used for research on multiple cancer types. One important part of the evaluation of tumors grafted onto the CAM is the measurement of tumor-induced angiogenesis. In order to address this central aspect, we utilized the novel PeriCam perfusion speckle imager (PSI) system high resolution (HR) model (Perimed AB, Järfälla, Sweden), which is based on laser speckle contrast imaging (LSCI) for the semiquantitative measurement of blood flow in the CAM model. This method enables a fast and accurate analysis of the angiogenesis of cell line tumors and primary tumors that are grafted onto the CAM. The proposed model can be regarded as a precursor model for personalized cancer therapy.

Atorvastatin inhibits the proliferation of MKN45-derived gastric cancer stem cells in a mevalonate pathway-independent manner.

Gastric cancer stem cells (GCSCs) are a major cause of radioresistance and chemoresistance in gastric cancer (GC). Therefore, targeting GCSCs is regarded as a powerful strategy for the effective treatment of GC. Atorvastatin is a widely prescribed cholesterol-lowering drug that inhibits 3-hydroxy-3-methylglutaryl-coenzyme A reductase, a rate-limiting enzyme in the mevalonate pathway. The anticancer activity of atorvastatin, a repurposed drug, is being investigated; however, its therapeutic effect and molecular mechanism of action against GCSCs remain unknown. In this study, we evaluated the anticancer effects of atorvastatin on MKN45-derived GCSCs. Atorvastatin significantly inhibited the proliferative and tumorsphere-forming abilities of MKN45 GCSCs in a mevalonate pathway-independent manner. Atorvastatin induced cell cycle arrest at the G0/G1 phase and promoted apoptosis by activating the caspase cascade. Furthermore, atorvastatin exerted an antiproliferative effect against MKN45 GCSCs by inhibiting the expression of cancer stemness markers, such as CD133, CD44, integrin α6, aldehyde dehydrogenase 1A1, Oct4, Sox2, and Nanog, through the downregulation of β-catenin, signal transducer and activator of transcription 3, and protein kinase B activities. Additionally, the combined treatment of atorvastatin and sorafenib, a multi-kinase targeted anticancer drug, synergistically suppressed not only the proliferation and tumorsphere formation of MKN45 GCSCs but also the in vivo tumor growth in a chick chorioallantoic membrane model implanted with MKN45 GCSCs. These findings suggest that atorvastatin can therapeutically eliminate GCSCs.

Acute lymphoblastic leukemia necessitates GSH-dependent ferroptosis defenses to overcome FSP1-epigenetic silencing

Ferroptosis is a form of cell death triggered by phospholipid hydroperoxides (PLOOH) generated from the iron-dependent oxidation of polyunsaturated fatty acids (PUFAs). To prevent ferroptosis, cells rely on the antioxidant glutathione (GSH), which serves as cofactor of the glutathione peroxidase 4 (GPX4) for the neutralization of PLOOHs. Some cancer cells can also limit ferroptosis through a GSH-independent axis, centered mainly on the ferroptosis suppressor protein 1 (FSP1). The significance of these two anti-ferroptosis pathways is still poorly understood in cancers from hematopoietic origin. Here, we report that blood-derived cancer cells are selectively sensitive to compounds that block the GSH-dependent anti-ferroptosis axis. In T- and B- acute lymphoblastic leukemia (ALL) cell lines and patient biopsies, the promoter of the gene coding for FSP1 is hypermethylated, silencing the expression of FSP1 and creating a selective dependency on GSH-centered anti-ferroptosis defenses. In-trans expression of FSP1 increases the resistance of leukemic cells to compounds targeting the GSH-dependent anti-ferroptosis pathway. FSP1 over-expression also favors ALL-tumor growth in an in vivo chick chorioallantoic membrane (CAM) model. Hence, our results reveal a metabolic vulnerability of ALL that might be of therapeutic interest.

A Face-To-Face Comparison of Tumor Chicken Chorioallantoic Membrane (TCAM) In Ovo with Murine Models for Early Evaluation of Cancer Therapy and Early Drug Toxicity.

Simple SummaryCancer remains a major health issue, and the development of new drug strategy is still mandatory. Currently, rodent models remain widely used in order to identify the first proof of concept of drug efficacy. Nevertheless, ethical considerations, cost, and time constraints highlight the need to develop alternatives to limit the use of conscious animals. Here, we showed in a face-to-face comparison that tumor-bearing eggs and tumor-bearing mice had a similar chemotherapy response in four different cancer models. We think that the so-called tumor chicken chorioallantoic membrane (TCAM) model may represent a relevant avenue for evaluating cancer treatment according to the 3Rs strategy in “The Principles of Humane Experimental Technique” aiming to reduce, refine, and replace animals to limit their number and suffering in experiments.Ethical considerations, cost, and time constraints have highlighted the need to develop alternatives to rodent in vivo models for evaluating drug candidates for cancer. The tumor chicken chorioallantoic membrane (TCAM) model provides an affordable and fast assay that permits direct visualization of tumor progression. Tumors from multiple species including rodents and human cell lines can be engrafted. In this study, we engrafted several tumor models onto the CAM and demonstrated that the TCAM model is an alternative to mouse models for preliminary cancer drug efficacy testing and toxicity analysis. Tumor cells were deposited onto CAM, and then grown for up to an additional 10 days before chronic treatments were administered. The drug response of anticancer therapies was screened in 12 tumor cell lines including glioblastoma, melanoma, breast, prostate, colorectal, liver, and lung cancer. Tumor-bearing eggs and tumor-bearing mice had a similar chemotherapy response (cisplatin and temozolomide) in four human and mouse tumor models. We also demonstrated that lethality observed in chicken embryos following chemotherapies such as cisplatin and cyclophosphamide were associated with corresponding side-effects in mice with body weight loss. According to our work, TCAM represents a relevant alternative model to mice in early preclinical oncology screening, providing insights for both the efficacy and the toxicity of anticancer drugs.

LB1027 An adipose-derived stem cell-engineered patch represents a promising treatment for chronic wounds

Mesenchymal stem cell (MSC)-based therapies are emerging as promising approach to treat chronic wounds, although uncontrolled/sub-optimal delivery represents a major threat to their wide-spread clinical adoption. Here we report a comprehensive pre-clinical evaluation program on the mechanism of action, efficacy and safety of an easy-to-use patch that concentrates MSC extracted from the human fat (ASCs) in a clinical-grade sponge made of porcine crosslinked-gelatin. ASC were derived from the abdominal/skin fat of four ischemic patients. Microarray data revealed that ASC grown within the patch upregulate the transcription of genes important for wound healing, including VEGF, CXCL12 and FGF7. The patch acted both as a concentrator and a reservoir of ASC-derived factors and sponge-derived fragments having healing capacity. The ASC-patch promoted dermal fibroblast survival, epidermal epithelialization and neovascularization, as shown in a chick chorioallantoic membrane model. No tumor formation was observed in immunodeficient Nude mice subcutaneously transplanted with the ASC-patch. Finally, ASC-patches prepared from syngeneic rats promoted faster healing and re-vascularization of full-thickness skin defects in a pe-clinical rat animal model of ischemic wounds. Together, we provide here compelling pre-clinical evidence that patches concentrating ASCs within crosslinked gelatin may represent a convenient and effective tool for the management of chronic wounds.

The Role of Citrate Homeostasis in Merkel Cell Carcinoma Pathogenesis.

Simple SummaryMerkel cell carcinoma (MCC) is a rare but highly aggressive skin cancer. Despite important progress, overall understanding of the events that drive MCC carcinogenesis remains incomplete. We discovered that the plasma membrane citrate transporter (pmCiC) is upregulated in Merkel cell carcinoma cell lines. Cancer cells import extracellular citrate via pmCiC to support their metabolism, which is critical to support proliferation and metastatic spread. In this study, we show that inhibition of pmCiC can decrease the growth rate of Merkel cell carcinoma cell lines. Targeting pmCiC and thereby the tumor metabolism should be considered further as a potential anti-cancer therapy.Merkel cell carcinoma (MCC) is a rare but highly aggressive tumor of the skin with a poor prognosis. The factors driving this cancer must be better understood in order to discover novel targets for more effective therapies. In the search for targets, we followed our interest in citrate as a central and critical metabolite linked to fatty acid synthesis in cancer development. A key to citrate uptake in cancer cells is the high expression of the plasma membrane citrate transporter (pmCiC), which is upregulated in the different adenocarcinoma types tested so far. In this study, we show that the pmCiC is also highly expressed in Merkel cell carcinoma cell lines by western blot and human tissues by immunohistochemistry staining. In the presence of extracellular citrate, MCC cells show an increased proliferation rate in vitro; a specific pmCiC inhibitor (Na+-gluconate) blocks this citrate-induced proliferation. Furthermore, the 3D in vivo Chick Chorioallantoic Membrane (CAM) model showed that the application of Na+-gluconate also decreases Merkel cell carcinoma growth. Based on our results, we conclude that pmCiC and extracellular citrate uptake should be considered further as a potential novel target for the treatment of Merkel cell carcinoma.

Abstract 3119: Circulating cancer stem cells as a tool for generating patient-derived xenografts on chick chorioallantoic membrane (CAM) in cancer patients

Abstract Background: Circulating cancer stem cells (cCSCs) are a small aggressive subset of circulating tumor cells with cancer stem cells features: resistance to diverse cancer treatments and the capacity for generating new metastases. Patient-derived xenografts (PDX) are an increasingly accepted tool in oncology, providing biologically meaningful models of many cancer types, and potential platforms for the development of precision oncology approaches. Commonly, mouse models are used for the xenotransplant assessment of potential new therapeutic targets in cancers. However, animal models do not necessarily represent the real world scenario and are costly and time consuming. An attractive alternative to such animal experiments is the chicken chorioallantoic membrane (CAM) assay. Methods: In this study, primary cultures from circulating cancer stem cells were established using sphere-forming assays. Subsequently, tumorspheres were transplanted onto the CAM membrane of fertilized chicken eggs to form secondary microtumors. Results: We have developed an innovative reliable in vitro platform for cultivation of CSCs from peripheral blood of cancer patients. The number of tumorspheres increased significantly with tumor progression. Patients with metastatic disease had statistically more tumorspheres as compared to patients without metastasis (30 vs 10/100µl blood, p&amp;lt;0.05). Patients with multiple metastases had more tumorspheres compared to patients with single metastases (60 vs 30/100µl blood, p&amp;lt;0.05). The number of tumorspheres was positively correlated with Ki-67, Her2 status and grade score in primary breast tumors. Tumorspheres showed self-renewal, growth potential, invasion and differentiation in vivo. Tumorspheres could be successfully grafted onto the CAM and grafting positively correlated with aggressiveness and proliferation capacity of the primary tumor. These tumors growing on the CAM pathologically closely resembled the primary tumor. Conclusion: The number of tumorspheres cultured from peripheral blood of cancer patients and the success rate of establishing PDX directly reflect the aggressiveness and proliferation capacity of the primary tumor. Our results support the CAM model using cCSC as a valuable alternative for xenotransplant models. It allows establishing new PDXs and providing a fast, low-cost, easy to use preclinical platform for cancer biology research, new drug development, treatment individualization, and biomarker discovery. Citation Format: Monika Pizon, Dorothea Schott, Ulrich Pachmann, Rainer Schobert, Katharina Pachmann. Circulating cancer stem cells as a tool for generating patient-derived xenografts on chick chorioallantoic membrane (CAM) in cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3119.

PEGylated nanohydrogels delivering anti-MicroRNA-21 suppress ovarian tumor-associated angiogenesis in matrigel and chicken chorioallantoic membrane models.

Introduction: Recently, MicroRNAs have gained increasing popularity as a novel nucleic acid-mediated medicine to regulate cancer-related protein expression. MicroRNA-21 (miR-21) is known as an oncogenic microRNA which is overexpressed in almost all cancers, including ovarian carcinoma that causes cisplatin (cis-Pt) resistance and vascular endothelial growth factor (VEGF) upregulation. So, miRNA-based therapy can be regarded as knocking down miR-21 expression, inducing tumor cell apoptosis, and suppressing tumor-associated angiogenesis. Methods: PEG5k-carboxymethylated polyethyleneimine nanohydrogels (PEG5k-CMPEI) were loaded with AntagomiR-21 (As-21) at different ratios of nitrogen to phosphorus (N/P). Particle size and ζ potential were determined for the As-21 loaded nanohydrogels. In the cellular experiments, miR-21 expression, cytotoxicity, and cis-Pt sensitivity were studied on A2780 ovarian cancer cell lines. Finally, tumor cell apoptosis and tumor cell-associated angiogenesis were explored in vitro and in vivo. Results: The nanohydrogels, featuring homogeneous size distribution and redox-responsiveness, were steadily loaded by As-21 at the optimum N/P ratio of 5 without any aggregation as determined by transmission electron microscopy (TEM). As-21-loaded nanohydrogels caused sequence-specific suppression of miR-21 expression and provoked apoptosis through ROS generation and caspase 3 activation. Cisplatin cytotoxicity was remarkably enhanced in A2780R as compared to A2780S following co-incubation with As-21-loaded nanohydrogels. Interestingly, the condition of the medium derived from As-21 nanohydrogel-treated A2780R cells inhibited VEGF suppression in human umbilical vein endothelial cells (HUVECs) and the formation of tubes in Matrigel. Moreover, the condition medium caused angiogenesis inhibition in the chicken chorioallantoic membrane (CAM) model. Conclusion: These results suggest that nanohydrogel-based delivery of As-21 can be a promising neoadjuvant therapy for treating resistant tumors via apoptosis induction and angiogenesis suppression.

Laser coagulation and hemostasis of large diameter blood vessels: effect of shear stress and flow velocity

Photocoagulation of blood vessels offers unambiguous advantages to current radiofrequency approaches considering the high specificity of blood absorption at available laser wavelengths (e.g., 532 nm and 1.064 µm). Successful treatment of pediatric vascular lesions, such as port-wine stains requiring microvascular hemostasis, has been documented. Although laser treatments have been successful in smaller diameter blood vessels, photocoagulation of larger sized vessels is less effective. The hypothesis for this study is that a primary limitation in laser coagulation of large diameter blood vessels (500–1000 µm) originates from shear stress gradients associated with higher flow velocities along with temperature-dependent viscosity changes. Laser (1.07 µm) coagulation of blood vessels was tested in the chicken chorio-allantoic membrane (CAM). A finite element model is developed that includes hypothetical limitations in laser coagulation during irradiation. A protocol to specify laser dosimetry is derived from OCT imaging and angiography observations as well as finite element model results. Laser dosimetry is applied in the CAM model to test the experimental hypothesis that blood shear stress and flow velocity are important parameters for laser coagulation and hemostasis of large diameter blood vessels (500–1000 µm). Our experimental results suggest that shear stress and flow velocity are fundamental in the coagulation of large diameter blood vessels (500–1000 µm). Laser dosimetry is proposed and demonstrated for successful coagulation and hemostasis of large diameter CAM blood vessels.

The synthetic non pungent capsaicin analog Arvanil displays robust anti‐tumor activity in human small cell lung cancer

The nutritional compound capsaicin is the hot spicy pungent ingredient of chili peppers. Capsaicin is a pain‐relieving agent and is found in several over‐the counter pain medications. However, recent studies have shown that capsaicin has profound anti‐neoplastic effects in several types of human cancers. The applications of capsaicin as a clinically useful drug are limited by its unpleasant side effects, such as gastric irritation, stomach cramps and burning sensation. This has led to extensive research focused on the identification and rational design of second‐generation capsaicin analogs, which possess greater bioactivity than capsaicin. Our laboratory performed an SAR study using a panel of non‐pungent capsaicin analogs and identified Arvanil as the hit compound. Arvanil triggered robust apoptosis in a panel of human small cell lung cancer (SCLC). The growth‐suppressive activity of Arvanil was confirmed in chicken chorioallantoic membrane (CAM) models. Finally, the dietary administration of Arvanil potently decreased the growth rate of human SCLC tumors xenotransplanted in athymic mice. The pro‐apoptotic activity of Arvanil was mediated by the TRPV1 receptor and the calpain pathway. Non‐pungent capsaicin analogs like Arvanil may be promising drug candidates for the management and treatment of human SCLC.

Investigating 3R In Vivo Approaches for Bio-Distribution and Efficacy Evaluation of Nucleic Acid Nanocarriers: Studies on Peptide-Mimicking Ionizable Lipid.

Formulations based on ionizable amino-lipids have been put into focus as nucleic acid delivery systems. Recently, the in vitro efficacy of the lipid formulation OH4:DOPE has been explored. However, in vitro performance of nanomedicines cannot correctly predict in vivo efficacy, thereby considerably limiting pre-clinical translation. This is further exacerbated by limited access to mammalian models. The present work proposes to close this gap by investigating in vivo nucleic acid delivery within simpler models, but which still offers physiologically complex environments and also adheres to the 3Rguidelines (replace/reduce/refine) to improve animal experiments. The efficacy of OH4:DOPE as a delivery system for nucleic acids is demonstrated using in vivo approaches. It is shown that the formulation is able to transfect complex tissues using the chicken chorioallantoic membrane model. The efficacy of DNA and mRNA lipoplexes is tested extensively in the zebra fish (Danio rerio) embryo which allows the screening of biodistribution and transfection efficiency. Effective transfection of blood vessel endothelial cells is seen, especially in the endocardium. Both model systems allow an efficacy screening according to the 3R guidelines bypassing the in vitro-in vivo gap. Pilot studies in mice are performed to correlate the efficacy of in vivo transfection.

The Chick Embryo Chorioallantoic Membrane Model: A Research Approach for Ex Vivo and In Vivo Experiments.

The chick chorioallantoic membrane (CAM) model has attracted a great deal of interest in pharmaceutical and biological research as an alternative or complimentary in vivo assay to animal models. Traditionally, CAM assay has been widely used to perform some toxicological studies, specifically to evaluate the skin, ocular and embryo toxicity of new drugs and formulations, and to perform angiogenesis studies. Due to the possibility to generate the tumors onto the CAM, this model has also become an excellent strategy to evaluate the metastatic potential of different tumours and to test the efficacy of novel anticancer therapies in vivo. Moreover, in the recent years, its use has considerably grown in other research areas, including the evaluation of new anti-infective agents, the development of biodistribution studies and in tissue engineering research. This manuscript provides a critical overview of the use of CAM model in pharmaceutical and biological research, especially to test the toxicity of new drugs and formulations and the biodistribution and the efficacy of novel anticancer and antiinfective therapies, analyzing its advantages and disadvantages in comparison to animal models. The chick chorioallantoic membrane model shows a great utility in several research areas, such as cancer, toxicology, biodistribution studies and anti-infective therapies. In fact, it has become an intermediate stage between in vitro experiments and animal studies, and, in the case of toxicological studies (skin and ocular toxicity), it has even replaced the animal models.

Hydrostatic pressure stimulates the osteogenesis and angiogenesis of MSCs/HUVECs co-culture on porous PLGA scaffolds

In native bone tissue regeneration, blood vessels, providing oxygen and nutrition for tissues, can promote the regeneration of bone and accelerate the repair of a defected area. In this study, Poly(D, L-lactic-co-glycolic acid) (PLGA) inverse opal scaffolds with high pore interconnectivity were fabricated and further modified with vascular endothelial growth factor (VEGF). The rat bone marrow derived mesenchymal stem cells (rMSCs) and human umbilical vein endothelial cells (HUVECs) were co-cultured onto the scaffolds to enhance vascularization for bone tissue regeneration. Cell attachment, viability, proliferation, and morphology were detected by cell counting kit-8 (CCK-8) assay, live and dead staining and scanning electron microscopy (SEM). Hydrostatic pressure with 0–279 KPa and 1 Hz one hour per day for 7 days was applied to tissue engineered bone constructs to investigate whether the loading stimulation can promote osteogenesis and angiogenesis mutually evaluated in parallel by multiple in vitro assays and in an in vivo chicken chorioallantoic membrane (CAM) model. The results indicated that the immobilization of VEGF can improve biocompatibility of PLGA scaffolds and promote cell attachment and proliferation. The cell-scaffold constructs showed higher CD31 expression because of the angiogenic differentiation of rMSCs in hydrostatic loading culture condition in vitro. The in vivo CAM model experiment demonstrated that hydrostatic loading stimulated angiogenic differentiation of rMSCs can accelerate tubulogenesis. Furthermore, the new capillaries formed in cell-scaffold constructs were conducive to calcium deposition in vivo.

The Different Temozolomide Effects on Tumorigenesis Mechanisms of Pediatric Glioblastoma PBT24 and SF8628 Cell Tumor in CAM Model and on Cells In Vitro.

It is necessary to elucidate the individual effects of temozolomide (TMZ) on carcinogenesis and tumor resistance to chemotherapy mechanisms. The study aimed to investigate the TMZ 50 and 100 μM dose effect difference between PBT24 and SF8628 cell line high-grade pediatric glioblastoma (phGBM) xenografts in a chicken chorioallantoic membrane (CAM) model, on PCNA and EZH2 immunohistochemical expression in the tumor and on the expression of NKCC1, KCC2, E- and N-cadherin genes in TMZ-treated and control cell groups in vitro. TMZ at a 100 μg dose reduced the incidence of PBT24 xenograft invasion into the CAM, CAM thickening and the number of blood vessels in the CAM (p < 0.05), but did not affect the SF8628 tumor in the CAM model. The TMZ impact on PBT24 and SF8628 tumor PCNA expression was similarly significantly effective but did not alter EZH2 expression in the studied tumors. The TMZ at 50 μM caused significantly increased RNA expression of the NKCC1 gene in both studied cell types compared with controls (p < 0.05). The expression of the KCC2 gene was increased in PBT24 TMZ-treated cells (p < 0.05), and no TMZ effect was found in SF8628-treated cells. The study supports the suggestion that individual sensitivity to TMZ should be assessed when starting treatment.

In Vivo Vasospasm Induction by Ultrasound Application in the Chicken Chorioallantoic Membrane Model

Cerebral vasospasm is a highly investigated phenomenon in neurovascular research. Experimental vasospasm models are irreplaceable for the evaluation of new antivasospastic drugs. In this study, we assessed the reliability of in vivo vasospasm induction by ultrasound application in the chicken chorioallantoic membrane (CAM) model. After incubation of fertilized chicken eggs for four days, a fenestration was performed to enable examination of the CAM vessels. On the thirteenth day, continuous-wave ultrasound (3 MHz, 1 W/cm2) was applied on the CAM vessels for 60 s. The ultrasound effect on the vessels was recorded by life imaging (5-MP HD-microscope camera, Leica®). The induced vessel diameter changes were evaluated in a defined time interval of 20 min using a Fiji macro. The vessel diameter before and after sonication was measured and the relative diameter reduction was determined. A first reduction of vessel diameter was observed after three minutes with an average vessel-diameter decrease to 77%. The maximum reduction in vessel diameter was reached eight minutes after sonication with an average vessel diameter decrease to 57% (mean relative diameter reduction of 43%, range 44–61%), ANOVA, p = 0.0002. The vasospasm persisted for all 20 recorded minutes post induction. Vasospasm can be reliably induced by short application of 3 MHz-ultrasound to the CAM vessels. This might be a suitable in vivo model for the evaluation of drug effects on vasospasm in an experimental setting as intermediary in the transition process from in vitro to in vivo assessment using animal models.