System and sequential culture media for in vitro fertilization

Abstract

Instead of immersing human reproductive cells in a single culture medium throughout the various procedures used in IVF, a process is provided by which the reproductive cells may be moved through a sequence of distinct culture media as the various IVF procedures are carried out. In one implementation, the culture media specifically formulated to provide a physical environment similar to that found within the female reproductive tract and conducive to growth and development of human reproductive cells during the various stages of the IVF process. In this regard, specifically formulated culture media can be applied to support the reproductive cells in one or more of the following procedures: oocyte retrieval and handling; oocyte maturation; ordinary fertilization; oocyte, zygote and embryo examination and biopsy; embryonic development to the eight-cell stage; embryonic development to the blastocyst stage; embryo transfer, and cryopreservation.

Description

FIELD OF THE INVENTION The present invention relates generally to human in vitro fertilization (IVF) and, in particular, to a sequential culture media system and process to be used in oocyte retrieval, handling and maturation, sperm preparation, fertilization, embryo development and transfer, and cryopreservation. The invention provides the gametes, zygote and developing embryo with a physical environment adapted to their physiological needs, so supporting their normal growth and development in vitro and increasing the likelihood of successful pregnancy. BACKGROUND OF THE INVENTION In vitro fertilization seeks to duplicate, to a large extent, the conditions and processes normally occurring within the female reproductive system that are necessary to oocyte development, fertilization and early embryonic development. In the clinic and laboratory, IVF involves several discrete procedures, such as collection of the oocytes from the ovary of the mother, preparation of the sperm, fertili...

AI Technical Summary

Benefits of technology

It has been recognized that IVF processes may be improved by providing specific media and media sequences for supporting gametes, zygotes and developing embryos relative to various phases of the IVF process. In certain respects, such media and sequences better reflect in vivo development. Within the female reproductive system, the oocyte is developed within and released from the ovary during ovulation, and proceeds through the oviduct towards the uterus. During this journey, it experiences a dynamic physical environment. The fluid of the oviduct contains a number of components that provide nourishment to the oocyte and its surrounding cumulus cells, and that also appear to interact with the oocyte and its cumulus cells, so stimulating development. Similarly, the fluid of the female reproductive tract provides nourishment to sperm traveling through the oviduct, and also stimulates certain changes in the sperm necessary to fertilization. Once fertilization occurs, the resulting zygote travels down the oviduct and enters the uterus approximately three days later, undergoing internal transformation and experiencing a changing environment.

In view of the foregoing, an important object of the present invention is to further improve and enhance the culture of human reproductive cells in vitro. The invention is intended to promote the health and viability of the gametes, zygote and embryo at various stages of the IVF process, thereby improving the overall efficiency of the IVF process and increasing pregnancy rates.

In general, the present invention involves the application of separate media specifically formulated to meet the physiological needs of the gametes, zygote and / or developing embryo in various stages of their development, and to support the processes necessary to accomplish fertilization and embryonic development in vitro. The present invention also generally contemplates a sequential culture media system, in which the separate media utilized have integrated formulations, intended to minimize trauma to the reproductive cells as they are moved from one medium to another during the IVF process.

According to a further aspect of the invention, different media are used for two different phases of the IVF process, such as oocyte collection and maturation, sperm preparation, fertilization, embryo development and / or embryo transfer. One associated process involves obtaining a gamete from a first medium and introducing the gamete into a second medium different from the first medium, wherein fertilization occurs in the second medium. The step of obtaining a gamete from a first medium may include extracting an oocyte from an oocyte collection medium or oocyte maturation medium as described above. Additionally or alternatively, the step of obtaining may involve extracting sperm from a sperm preparation and fertilization medium as described above which, in turn, may be different from the oocyte medium. The step of introducing the gamete into the second medium may involve introducing the sperm and / or oocyte into a fertilization medium, or injecting sperm into an oocyte contained in the second medium. The various media may have integrated formulations for minimizing trauma to the reproductive cells.

Problems solved by technology

Cleavage stage embryos, like the oocyte, are susceptible to loss of amino acids through their cell membranes when surrounded by an environment having a low concentration of such factors.

Such loss of internal amino acids can have devastating effects.

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