Modified Oocyte Nuclear Transfer for IVF Success
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Solution Overview
Problem
Current methods for in vitro fertilization (IVF) face challenges such as decreased oocyte quality and fertility with advancing maternal age, leading to low success rates and increased miscarriage, as well as the transmission of mitochondrial DNA mutations, which can cause life-threatening disorders.
Innovation Solution
The development of modified oocytes with a nuclear genome derived from a developmentally incompetent oocyte and cytoplasm from a developmentally competent oocyte, using improved nuclear transfer methods that involve specific phases of the meiotic cycle and spindle states to enhance developmental competence and prevent mitochondrial DNA mutation transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional IVF methods are used with oocytes from older females, then the procedure is simpler and less invasive, but the developmental potential of oocytes decreases and success rates fall below 5%
Solution Approach 1:
The oocyte is segmented into two functional components: the nuclear genome (containing maternal genetic material) and the cytoplasm (containing mitochondria and developmental factors). The nuclear genome is transferred to a recipient oocyte cytoplast, separating the genetic identity from the cytoplasmic environment. This segmentation allows the nuclear genome from an older oocyte to be placed in a younger, developmentally competent cytoplasmic environment.
Solution Approach 2:
The nuclear genome is extracted from the donor oocyte and the recipient oocyte is enucleated (having its nucleus removed). This extraction allows the nuclear genome to be transferred while the recipient oocyte provides a fresh cytoplasmic environment free from age-related deterioration, thereby improving developmental potential without requiring complex external interventions.
2Reliability
If nuclear transfer is performed to improve developmental competence, then oocyte quality improves, but the procedure becomes more complex and time-consuming
Solution Approach 1:
Both the donor and recipient oocytes are prepared in advance: the donor oocyte's nuclear genome is isolated and the recipient oocyte is enucleated before fusion. This preliminary preparation ensures that when the nuclear transfer occurs, both components are ready for immediate fusion, reducing procedural complexity and time requirements while maintaining high developmental competence.
Solution Approach 2:
An intermediary fusion process is used to combine the nuclear genome with the recipient cytoplast. This intermediary mechanism facilitates the merging of nuclear and cytoplasmic components in a controlled manner, simplifying the overall procedure by providing a standardized method for nuclear transfer that reduces operational difficulty.
3Quantity of substance
If oocytes are cultured for prolonged periods to maximize retrieval, then more oocytes are obtained, but developmental defects increase due to abnormal chromosome segregation
Solution Approach 1:
The nuclear genome is extracted from the donor oocyte and transferred to a fresh recipient cytoplast. This extraction removes the nuclear genome from the deteriorating cytoplasmic environment that causes chromosome segregation errors during prolonged culture. The transferred nucleus is placed in a young, healthy cytoplasmic environment that maintains proper chromosome segregation and developmental competence.
Solution Approach 2:
The nuclear genome is copied or transferred to a new cytoplasmic environment rather than attempting to rescue or repair the original oocyte. This copying approach creates a new developmental system with the same genetic material but in a rejuvenated cytoplasmic context, avoiding the chromosome segregation problems associated with prolonged culture of aged oocytes.
4Stability of the object's composition
If mitochondrial DNA mutations are present in the oocyte, then maternal inheritance is maintained, but life-threatening disorders are transmitted to offspring
Solution Approach 1:
The genetic material is segmented into nuclear DNA (maternal genome) and mitochondrial DNA (cytoplasmic genome). By transferring only the nuclear genome to a recipient cytoplast from a donor without mitochondrial mutations, the procedure maintains maternal nuclear genetic inheritance while replacing the harmful mitochondrial DNA with healthy mitochondria from the recipient donor.
Solution Approach 2:
The mitochondrial DNA is effectively extracted or replaced by using a recipient oocyte cytoplast that lacks the harmful mitochondrial mutations. The nuclear genome is transferred to this mutation-free cytoplasmic environment, thereby eliminating the transmission of life-threatening mitochondrial disorders while preserving maternal nuclear genetic identity.
Data Source
AI summary
The present invention provides modified oocytes having a nuclear genome derived from a first oocyte and cytoplasm derived from a second oocyte from a different subject, and methods for making and using such modified oocytes. The methods and compositions of the present invention can be useful in a variety of settings including, but not limited to, in in vitro fertilization (“IVF”) procedures.