Comparison of Genetically Engineered Immunodeficient Animal Models for Nonclinical Testing of Stem Cell Therapies

Synergistic Promoting Effects of X-Linked Inhibitor of Apoptosis Protein and Matrix on the In Vitro Follicular Maturation of Marmoset Follicles

BACKGROUND

In vitro follicular maturation (IVFM) of ovarian follicles is an emerging option for fertility preservation. Many paracrine factors and two-dimensional or three-dimensional (3D) environments have been used for optimization. However, since most studies were conducted using the murine model, the physiological differences between mice and humans limit the interpretation and adaptation of the results. Marmoset monkey is a non-human primate (NHPs) with more similar reproductive physiology to humans. In this study, we attempted to establish a 3D matrix (Matrtigel)-based IVFM condition for marmoset ovarian follicles in combination with anti-apoptotic factor, X-linked inhibitor of apoptosis protein (XIAP).

METHODS

Marmoset follicles were isolated as individual follicles and cultured in a single drop with the addition of 0, 10, and 100 μg/mL of XIAP molecules. Matured oocytes and granulosa cells from mature follicles were collected and analyzed. The average number of isolated follicles was less than 100, and primordial and antral follicles were abundant in the ovaries.

RESULTS

IVFM of marmoset follicles in 3D matrix conditions with XIAP increased the rates of survival and in vitro follicle development. Furthermore, oocytes from the 3D cultures were successfully fertilized and developed in vitro. The addition of XIAP increased the secretion of estradiol and aromatase. Furthermore, expression of granulosa-specific genes, such as bone morphogenetic protein 15, Oct4, and follicle-stimulating hormone receptor were upregulated in the in vitro-matured follicles than in normal, well-grown, and atretic follicles. Apoptosis-related B-cell lymphoma-2 was highly expressed in the atretic follicles than in the XIAP-treated follicles, and higher caspase-3 was localized in the XIAP-treated follicles.

CONCLUSION

In this study, we attempted to establish a 3D-matrix-based marmoset IVFM condition and demonstrated the synergistic effects of XIAP. The use of a 3D matrix may be applied as an optimal culture condition for marmoset ovarian follicles.

Animal Models in Allogenic Solid Organ Transplantation

Animal models provide the link between in vitro research and the first in-man application during clinical trials. They provide substantial information in preclinical studies for the assessment of new therapeutic interventions in advance of human clinical trials. However, each model has its advantages and limitations in the ability to imitate specific pathomechanisms. Therefore, the selection of an animal model for the evaluation of a specific research question or evaluation of a novel therapeutic strategy requires a precise analysis. Transplantation research is a discipline that largely benefits from the use of animal models with mouse and pig models being the most frequently used models in organ transplantation research. A suitable animal model should reflect best the situation in humans, and the researcher should be aware of the similarities as well as the limitations of the chosen model. Small animal models with rats and mice are contributing to the majority of animal experiments with the obvious advantages of these models being easy handling, low costs, and high reproductive rates. However, unfortunately, they often do not translate to clinical use. Large animal models, especially in transplantation medicine, are an important element for establishing preclinical models that do often translate to the clinic. Nevertheless, they can be costly, present increased regulatory requirements, and often are of high ethical concern. Therefore, it is crucial to select the right animal model from which extrapolations and valid conclusions can be obtained and translated into the human situation. This review provides an overview in the models frequently used in organ transplantation research.