The potential effect of leptin co-administration on photodynamic damage using quail chorioallantoic membrane model

BACKGROUND

The chorioallantoic membrane (CAM) of the Japanese quail is an excellent model for studying photodynamic therapy (PDT) due to its rich vascularization. PDT is used not only in oncological treatment but also in infectious diseases, or psoriasis, where it yields significant advantages. This treatment also has its limitations, such as burning, itching, erythema, redness, swelling, and delayed wound healing. The aim of this study was to analyse the potentially protective properties of the tissue hormone leptin during PDT.

METHODS

Japanese quail embryos incubated ex ovo were used in this experiment. On the 9th day of embryonic development, leptin (5 μg) and photosensitiser hypericin (79 μM) were topically applied, followed by irradiation. The effect of leptin co-administration was evaluated from CAM images and histological structure analysis, histological samples, and qPCR, where the expression of genes involved in angiogenesis, apoptosis, and oxidative stress was monitored.

RESULTS

We observed vascular damage in all experimental groups, the highest damage was found after the application of hypericin without leptin coadministration. Histological analysis confirmed the protective effect of leptin. qPCR analysis presented differences in FREK gene expression, but also in genes involved in oxidative stress like SOD, NRF-1, NRF-2, and GPX7. The application of leptin significantly reduced the expression of apoptosis regulatory proteins CASP3, cytochrome C, and APAF1.

CONCLUSIONS

Our results in the CAM model suggest a possible protective effect of leptin to prevent PDT damage and aid in the subsequent regeneration of target tissues after antimicrobial PDT.

Chemotherapy-triggered changes in stromal compartment drive tumor invasiveness and progression of breast cancer

Background

Chemotherapy remains a standard treatment option for breast cancer despite its toxic effects to normal tissues. However, the long-lasting effects of chemotherapy on non-malignant cells may influence tumor cell behavior and response to treatment. Here, we have analyzed the effects of doxorubicin (DOX) and paclitaxel (PAC), commonly used chemotherapeutic agents, on the survival and cellular functions of mesenchymal stromal cells (MSC), which comprise an important part of breast tumor microenvironment.

Methods

Chemotherapy-exposed MSC (DOX-MSC, PAC-MSC) were co-cultured with three breast cancer cell (BCC) lines differing in molecular characteristics to study chemotherapy-triggered changes in stromal compartment of the breast tissue and its relevance to tumor progression in vitro and in vivo. Conditioned media from co-cultured cells were used to determine the cytokine content. Mixture of BCC and exposed or unexposed MSC were subcutaneously injected into the immunodeficient SCID/Beige mice to analyze invasion into the surrounding tissue and possible metastases. The same mixtures of cells were applied on the chorioallantoic membrane to study angiogenic potential.

Results

Therapy-educated MSC differed in cytokine production compared to un-exposed MSC and influenced proliferation and secretory phenotype of tumor cells in co-culture. Histochemical tumor xenograft analysis revealed increased invasive potential of tumor cells co-injected with DOX-MSC or PAC-MSC and also the presence of nerve fiber infiltration in tumors. Chemotherapy-exposed MSC have also influenced angiogenic potential in the model of chorioallantoic membrane.

Conclusions

Data presented in this study suggest that neoadjuvant chemotherapy could possibly alter otherwise healthy stroma in breast tissue into a hostile tumor-promoting and metastasis favoring niche. Understanding of the tumor microenvironment and its complex net of signals brings us closer to the ability to recognize the mechanisms that prevent failure of standard therapy and accomplish the curative purpose.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02087-2.

Chorioallantoic Membrane Models of Various Avian Species: Differences and Applications

The chorioallantoic membrane model (CAM) of an avian embryo is used as an experimental model in various fields of research, including angiogenesis research and drug testing, xenografting and cancer research, and other scientific and commercial disciplines in microbiology, biochemistry, cosmetics, etc. It is a low-cost, low-maintenance, and well-available in vivo animal model that is non-sentient and can be used as an alternative for other mammal experimental models. It respects the principles of the "3R" rule (Replacement, Reduction, and Refinement)-conditions set out for scientific community providing an essential framework for conducting a more human animal research, which is also in line with constantly raising public awareness of welfare and the ethics related to the use of animal experimental models. In this review, we describe the chorioallantoic membrane of an avian embryo, focusing on its properties and development, its advantages and disadvantages as an experimental model, and the possibilities of its application in various fields of biological research. Since the most common chicken CAM model is already well known and described in many publications, we are particularly focusing on the advantages and application of less known avian species that are used for the CAM model-quail, turkey, and duck.

Modulation of angiogenesis by topical application of leptin and high and low molecular heparin using the Japanese quail chorioallantoic membrane model

Pathological angiogenesis characterized by uncontrollable vessel growth is an accompanying feature of many diseases. The avian embryo chorioallantoic membrane (CAM) is an excellent model for angiogenesis research. In our study we used a less common Japanese quail CAM model for the testing of angiogenic potential of leptin, high-molecular (heparin sodium) andlow-molecular (nadroparin calcium) heparins. Heparins play a significant role in vascular endothelial cell function, and they are able to modulate the activities of angiogenic growth factors. On embryonic day 7 leptin (5 μg per CAM), heparin sodium (75 IU per CAM) and nadroparin calcium (47.5 IU per CAM) in 500 μl PBS were applied on the CAM surface. After 24 h the fractal dimension (Df) of the vasculature was evaluated. Samples from each group were histologically analyzed and VEGF-A and Quek1 expression were detected by qPCR. Df was significantly increased in the leptin group. A moderate stimulatory effect of heparin sodium and an inhibitory effect of nadroparin calcium were observed. Both leptin and heparin sodium caused a noticeable increase in the CAM thickness compared to the control and nadroparin calcium groups. We observed an increased number of blood vessels and accumulation of fibroblasts. There was no significant impact on gene expression of VEGF-A and Quek1 24 h after treatment, however, trends similar to the changes in Df and CAM thickness were present. The resulting effect of nadroparin administration on Quek1 levels was exactly the opposite to that of leptin (p < 0.05).

In ovo administration of human recombinant leptin shows dose dependent angiogenic effect on chicken chorioallantoic membrane

Background

Leptin, the cytokine produced by white adipose tissue is known to regulate food energy homeostasis through its hypothalamic receptor. In vitro studies have demonstrated that leptin plays a major role in angiogenesis through binding to the receptor Ob-R present on ECs by stimulating and initiating new capillary like structures from ECs. Various in vivo studies indicate that leptin has diverse effect on angiogenesis. A few reports have showed that leptin exerts pro angiogenic effects while some suggested that it has antiangiogenic potential. It is theoretically highly important to understand the effect of leptin on angiogenesis to use as a therapeutic molecule in various angiogenesis related pathological conditions. Chicken chorio allantoic membrane (CAM) on 9th day of incubation was incubated with 1, 3 and 5 μg concentration of HRL for 72 h using gelatin sponge. Images where taken after every 24 h of incubation and analysed with Angioguant software. The treated area was observed under microscope and histological evaluation was performed for the same. Tissue thickness was calculated morphometrically from haematoxylin and eosin stained cross sections. Reverse transcriptase PCR and immunohistochemistry were also performed to study the gene and protein level expression of angiogenic molecules.

Results

HRL has the ability to induce new vessel formation at the treated area and growth of the newly formed vessels and cellular morphological changes occur in a dose dependent manner. Increase in the tissue thickness at the treated area is suggestive of initiation of new capillary like structures. Elevated mRNA and protein level expression of VEGF165 and MMP2 along with the activation of ECs as demonstrated by the presence of CD34 expression supports the neovascularization potential of HRL.

Conclusion

Angiogenic potential of HRL depends on the concentration and time of incubation and is involved in the activation of ECs along with the major interaction of VEGF 165 and MMP2. It is also observed that 3 μg of HRL exhibits maximum angiogenic potential at 72 h of incubation. Thus our data suggest that dose dependent angiogenic potential HRL could provide a novel role in angiogenic dependent therapeutics such as ischemia and wound healing conditions.

Fractal analysis of extra-embryonic vascularization in Japanese quail embryos exposed to extremely low frequency magnetic fields

Magnetic fields (MF) can alter the dynamic behavior of vascular tissue and may have a stimulatory or inhibitory effect on blood vessel growth. Fractal geometry has been used in several studies as a tool to describe the development of blood vascular networks. Due to its self-similarity, irregularity, fractional dimension, and dependence on the scale of vessel dimensions, vascular networks can be taken as fractal objects. In this work, we calculated the fractal dimension by the methods of box counting (D(bc)) and information dimension (D(inf)) to evaluate the development of blood vessels of the yolk sac membrane (YSM) from quail embryos exposed to MF with a magnetic flux density of 1 mT and a frequency of 60 Hz. The obtained results showed that when the MF was applied to embryos aged between 48 and 72 h, in sessions of 2 h (6 h/day) and 3 h (9 h/day) with exposure intervals between 6 and 5 h, respectively, blood vascular formation was inhibited. Exposure sessions shorter than 2 h or longer than 3 h had no observable change on the vascular process. In contrast, the magnetic field had no observable change on the YSM vascular network for embryos aged between 72 and 96 h, irrespective of the exposure time. In conclusion, these results show a "window effect" regarding exposure time.

In ovo leptin administration inhibits chorioallantoic membrane angiogenesis in female chicken embryos through the STAT3-mediated vascular endothelial growth factor (VEGF) pathway

Previous studies indicate that leptin regulates placental angiogenesis and fetal growth in mammals and that in ovo leptin administration affects embryonic development and hatch weight in the chicken. To test the hypothesis that leptin affects embryonic growth through modifying chorioallantoic membrane (CAM) angiogenesis, we injected 0.5 μg of recombinant murine leptin into the albumen of fertilized eggs before incubation. On embryonic day 12 (E12), the number and the total area of blood vessels on CAM were measured, and expression of genes involved in angiogenesis was quantitated to show the possible mechanisms. Leptin in ovo administration decreased (P < 0.05) both the total area of blood vessels and the number of small-sized capillaries on CAM of E12 female chicken embryos, which coincided with significantly decreased (P < 0.05) embryo weight on E12 and BW at hatching. Vascular endothelial growth factor (VEGF) and inducible and endothelial nitric oxide synthases (iNOS and eNOS) were all downregulated (P < 0.05) in CAM both at the mRNA and protein/activity levels with reduced (P < 0.05) nitric oxide (NO) concentration in chorioallantoic fluid of female embryos. Furthermore, signal transducer and activator of transcription-3 (STAT3) was found to be diminished (P < 0.05) both at the mRNA and protein levels and associated with decreased (P < 0.05) binding of STAT3 to VEGF promotor in the CAM of leptin-treated E12 female embryos. These data suggest that in ovo leptin administration affects CAM angiogenesis and embryo growth in female chicken embryos, probably through STAT3-mediated VEGF/NO pathways.