Publicação
Mechanisms and effects of cell density of embryos in culture in in vitro fertilization processes in embryonary development
| Resumo: | Background and Objectives: The objective of achieving higher pregnancy rates in the area of human reproduction has promoted the search for new insights that could lead to a better embryonic development. The culture of embryos in groups aims to promote embryotrophic interaction, mediated by the secretion of paracrine and autocrine factors that induce mutual embryonic development, being crucial to evaluate the presence of factors that lead this evolution to fully understand the process. The present study aimed to explore what crucial knowledge could be obtained for the medically assisted reproduction area through the use of mid-infrared spectroscopy in the analysis of culture media spent by murine embryos and to evaluate retrospectively ovodonation cycle data for evaluation of the benefit of group human embryo culture (CG) versus individual culture (IC). In this way, it would be possible to take a position regarding the theory of the benefit of group culture and to understand whether the FTIR spectroscopy tool would be useful in evaluating the spectral profile of media spent by embryos. Methods: This thesis is divided in three distinct methodological chapters: I) the analysis and comparison of the FTIR spectral profile of different commercial human embryo culture media. In order to increase the accuracy of this tool, pre-processing methods were carried out as atmospheric and baseline correction, normalizations and derivatives that minimize distortions and resolve overlapping bands. II) the analysis of the spectral profile of spent culture media of grouped murine embryos: the molecular profile of 47 culture media spent by murine embryos up to the state of two cells was studied, with a density variation between 3 to 114 embryos per drop were evaluated before and after fertilization. III) the retrospective analysis to assessthe impact of group culture on human embryonic development rates using data from Ginemed’s IVF unit: An analysis was performed on each ovodonation cycle to compare the results of individually culture embryos and those culture in groups. Results: In chapter I), it was observed through the pattern recognition method of Principal Component Analysis (PCA) and the pre-processing methods applied that FTIR spectroscopy is sensitive enough to recognize different molecular profiles between culture media, highlighting differences at aminoacids (aa) and lipids molecules. In chapter II), The analysis of culture media spent of murine embryos showed different spectral profiles between media analyzed individually, without being able to establish any link between variables (species, number of embryos, pre/post fertilization). In chapter III), the retrospective comparison of culture of human embryos in individual and groups, revealed similar developmental rates to the blastocyst stage between both strategies; i.e. it was not detected a positive effect of group culture. Conclusions: The FTIR spectroscopy enables to acquire the molecular profile of human embryo culture media. Despite this, it was not possible to acquire by PCA of spectral data of spent media from the murine embryos patterns associated to species, number of embryos, etc. In the human embryo population and conditions evaluated it was not possible to observe advantages of culture the embryos in group in relation to culture embryos individually. It is proposed as future work, to evaluate other spectral processing techniques and increase the dimension of the human embryos evaluated. |
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| Autores principais: | Ribeiro, Inês Barradas |
| Assunto: | Embryos Culture media Group embryo culture Human embryonic pre-implantation in vitro fertilization Embriões Meios de cultura Cultura de embriões em grupo Pré-implantação embrionária humana Fertilização in vitro |
| Ano: | 2021 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Instituto Politécnico de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório Científico do Instituto Politécnico de Lisboa |
| Resumo: | Background and Objectives: The objective of achieving higher pregnancy rates in the area of human reproduction has promoted the search for new insights that could lead to a better embryonic development. The culture of embryos in groups aims to promote embryotrophic interaction, mediated by the secretion of paracrine and autocrine factors that induce mutual embryonic development, being crucial to evaluate the presence of factors that lead this evolution to fully understand the process. The present study aimed to explore what crucial knowledge could be obtained for the medically assisted reproduction area through the use of mid-infrared spectroscopy in the analysis of culture media spent by murine embryos and to evaluate retrospectively ovodonation cycle data for evaluation of the benefit of group human embryo culture (CG) versus individual culture (IC). In this way, it would be possible to take a position regarding the theory of the benefit of group culture and to understand whether the FTIR spectroscopy tool would be useful in evaluating the spectral profile of media spent by embryos. Methods: This thesis is divided in three distinct methodological chapters: I) the analysis and comparison of the FTIR spectral profile of different commercial human embryo culture media. In order to increase the accuracy of this tool, pre-processing methods were carried out as atmospheric and baseline correction, normalizations and derivatives that minimize distortions and resolve overlapping bands. II) the analysis of the spectral profile of spent culture media of grouped murine embryos: the molecular profile of 47 culture media spent by murine embryos up to the state of two cells was studied, with a density variation between 3 to 114 embryos per drop were evaluated before and after fertilization. III) the retrospective analysis to assessthe impact of group culture on human embryonic development rates using data from Ginemed’s IVF unit: An analysis was performed on each ovodonation cycle to compare the results of individually culture embryos and those culture in groups. Results: In chapter I), it was observed through the pattern recognition method of Principal Component Analysis (PCA) and the pre-processing methods applied that FTIR spectroscopy is sensitive enough to recognize different molecular profiles between culture media, highlighting differences at aminoacids (aa) and lipids molecules. In chapter II), The analysis of culture media spent of murine embryos showed different spectral profiles between media analyzed individually, without being able to establish any link between variables (species, number of embryos, pre/post fertilization). In chapter III), the retrospective comparison of culture of human embryos in individual and groups, revealed similar developmental rates to the blastocyst stage between both strategies; i.e. it was not detected a positive effect of group culture. Conclusions: The FTIR spectroscopy enables to acquire the molecular profile of human embryo culture media. Despite this, it was not possible to acquire by PCA of spectral data of spent media from the murine embryos patterns associated to species, number of embryos, etc. In the human embryo population and conditions evaluated it was not possible to observe advantages of culture the embryos in group in relation to culture embryos individually. It is proposed as future work, to evaluate other spectral processing techniques and increase the dimension of the human embryos evaluated. |
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