Mitochondrial Replacement Techniques – Maternal Spindle Transfer
Mitochondrial replacement techniques (MRT) in general are designed to prevent the transmission of mitochondrial DNA (mtDNA) diseases from mother to child. These diseases vary in presentation and severity, but common symptoms include developmental delays, seizures, weakness and fatigue, muscle weakness, vision loss, and heart problems, leading to morbidity and in some cases premature death.
The spindle transfer (ST) technique is based on the transfer of the nuclear genome from the oocyte of an affected woman into an oocyte from a healthy donor that has had its own nuclear genome removed. After years of research, different groups have agreed on that the use of ST in human oocytes may represent a powerful technology to prevent the transmission of mitochondrial diseases from affected women into their children, or for the treatment of infertility caused by cytoplasmic-associated defects in oocytes. To establish clinical models for this new therapeutic approach, different research studies have been published demonstrating that the meiotic spindle can indeed be successfully replaced both in animal and human oocytes. As a matter of fact, due to this technique two healthy babies have been already born. At the moment, while the prevalence of patients with mtDNA diseases is not so common, one of the main causes of repeated IVF failure, e.g., implantation failure, in assisted reproduction techniques (ART) has been attributed to defects affecting the cytoplasm of the oocyte rather than nuclear DNA deficiencies. For these cases of infertility caused by ooplasmic defects, the transfer of the spindle-chromosome complex into a donor oocyte could thus represent a very valuable strategy to overcome this problem. Moreover, this ST technique would permit infertile women to have their own biological children, avoiding such couples to go through an egg donation cycle, that would result in a baby not genetically related to the mother.
Currently our clinic has been licensed from the National Medically Assisted Reproduction Authority to validate the ST technology in human oocytes, performing a series of clinical trials on donor eggs and explore its feasibility in the treatment of infertility problems attributed to cytoplasmic defects in the oocyte.