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Abstract
Mitochondrial disease is maternally inherited and refractory to treatment, but assisted reproduction methods can result in unaffected pregnancies. The authors provide estimates of the number of affected pregnancies per year in the United Kingdom and the United States.
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Nau JY. [Mitochondrial transfer: British genetic high risk bet]. REVUE MEDICALE SUISSE 2015; 11:426-427. [PMID: 25895227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
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31
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32
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Wise J. Mitochondrial donation could benefit 150 UK women a year, study says. BMJ 2015; 350:h536. [PMID: 25644022 DOI: 10.1136/bmj.h536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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33
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Legge M, Fitzgerald RP. Ethics of mitochondrial therapy for deafness. THE NEW ZEALAND MEDICAL JOURNAL 2014; 127:78-81. [PMID: 25399045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Mitochondrial therapy may provide the relief to many families with inherited mitochondrial diseases. However, it also has the potential for use in non-fatal disorders such as inherited mitochondrial deafness, providing an option for correction of the deafness using assisted reproductive technology. In this paper we discuss the potential for use in correcting mitochondrial deafness and consider some of the issues for the deaf community.
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O'Dowd A. UK will be groundbreaker if proposed regulations for mitochondrial donation are adopted, MPs hear. BMJ 2014; 349:g6431. [PMID: 25341875 DOI: 10.1136/bmj.g6431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Preble JM, Pacak CA, Kondo H, MacKay AA, Cowan DB, McCully JD. Rapid isolation and purification of mitochondria for transplantation by tissue dissociation and differential filtration. J Vis Exp 2014:e51682. [PMID: 25225817 PMCID: PMC4828055 DOI: 10.3791/51682] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Previously described mitochondrial isolation methods using differential centrifugation and/or Ficoll gradient centrifugation require 60 to 100 min to complete. We describe a method for the rapid isolation of mitochondria from mammalian biopsies using a commercial tissue dissociator and differential filtration. In this protocol, manual homogenization is replaced with the tissue dissociator's standardized homogenization cycle. This allows for uniform and consistent homogenization of tissue that is not easily achieved with manual homogenization. Following tissue dissociation, the homogenate is filtered through nylon mesh filters, which eliminate repetitive centrifugation steps. As a result, mitochondrial isolation can be performed in less than 30 min. This isolation protocol yields approximately 2 x 10(10) viable and respiration competent mitochondria from 0.18 ± 0.04 g (wet weight) tissue sample.
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Wise J. Mitochondrial donation is "not unsafe," review confirms. BMJ 2014; 348:g3723. [PMID: 24899669 DOI: 10.1136/bmj.g3723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Abstract
After the development of induced pluripotent stem cells (IPSCs) in 2007, the pressure to commercialize women's eggs for stem cell research could have been expected to lessen. However, the pressure to harvest human eggs in large quantities for research has not diminished; rather, it has taken different directions, for example in germline mitochondrial research. Yet there has been little acknowledgement of these technologies' need for human eggs, the possible risks to women and the ethical issues concerning potential exploitation. Rather, there has been a renewed campaign to legalize payment for eggs in research, although the actual scientific advances are at best modest. This article shows why a market in women's eggs is ethically problematic in terms of the doctor's duty to do no harm and the limitations of 'informed' consent.
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Abstract
This article outlines some of the main ethical considerations specifically relating to legalisation of mitochondrial donation. Safety requirements, were the technique to be legalised, are then discussed, followed by an exploration of parenthood in the context of mitochondrial donation. It is concluded that there are no ethical objections specifically relating to the legalisation of mitochondrial donation, but that various safety precautions must be established prior to its use, including the availability of relevant medical information about the mitochondrial donors to any resultant children. It is also found that introduction of this technique would not necessitate modifications to current British legal definitions of parenthood. However, it is clear that societal attitudes in this area are changing, and it is recommended that this opportunity be taken to review concepts of parenthood, particularly the number of parents a child may have at one time.
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Wise J. Draft UK regulations for mitochondrial donation are published. BMJ 2014; 348:g1846. [PMID: 24585821 DOI: 10.1136/bmj.g1846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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41
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Public asked about ethics of creating three-parent babies to prevent disease. THE PRACTISING MIDWIFE 2012; 15:6. [PMID: 23252063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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Szego MJ. Organelle transplantation should be legalized in Canada. JOURNAL OF OBSTETRICS AND GYNAECOLOGY CANADA 2011; 33:329. [PMID: 21851763 DOI: 10.1016/s1701-2163(16)34849-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Nagai S, Mabuchi T, Hirata S, Shoda T, Kasai T, Yokota S, Shitara H, Yonekawa H, Hoshi K. Oocyte Mitochondria: Strategies to Improve Embrbryogenesis. Hum Cell 2008; 17:195-201. [PMID: 16035504 DOI: 10.1111/j.1749-0774.2004.tb00043.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mitochondria play a central role to provide ATP for fertilization and preimplantation embryo development in the ooplasm. The mitochondrial dysfunction of oocyte has been proposed as one of the causes of high levels of developmental retardation and arrest that occur in preimplantation embryos generated using Assisted Reproductive Technology. Cytoplasmic transfer (CT) from a donor to a recipient oocyte has been applied to infertility due to dysfunctional ooplasm, with resulting pregnancies and births. However, neither the efficacy nor safety of this procedure has been appropriately investigated. In order to improve embryogenesis, we observed the mitochondrial distribution in ooplasma under the several conditions using mitochondrial GFP-transgenic mice (mtGFP-tg mice) in which the mitochondria are visualized by GFP. In this report, we will present our research about the mitochondrial distribution in ooplasm during early embryogenesis and the fate of injected donor mitochondria after CT using mtGFP-tg mice. The mitochondria in ooplasm from the germinal vesicle stage to the morula stage were accumulated in the perinuclear region. The mitochondria of the mtGFP-tg mouse oocyte transferred into the wild type mouse embryo could be observed until the blastocysts stage, suggesting that the mtGFP-tg mice oocyte is very useful for visual observation of the mitochondrial distribution in the oocyte, and that the aberrant early developmental competences due to the oocyte mitochondrial dysfunction may be overcome by transferring the "normal" mitochondria.
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Brenner CA, Kubisch HM, Pierce KE. Role of the mitochondrial genome in assisted reproductive technologies and embryonic stem cell-based therapeutic cloning. Reprod Fertil Dev 2007; 16:743-51. [PMID: 15740697 DOI: 10.1071/rd04107] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Accepted: 10/19/2004] [Indexed: 11/23/2022] Open
Abstract
Mitochondria play a pivotal role in cellular metabolism and are important determinants of embryonic development. Mitochondrial function and biogenesis rely on an intricate coordination of regulation and expression of nuclear and mitochondrial genes. For example, several nucleus-derived transcription factors, such as mitochondrial transcription factor A, are required for mitochondrial DNA replication. Mitochondrial inheritance is strictly maternal while paternally-derived mitochondria are selectively eliminated during early embryonic cell divisions. However, there are reports from animals as well as human patients that paternal mitochondria can occasionally escape elimination, which in some cases has led to severe pathologies. The resulting existence of different mitochondrial genomes within the same cell has been termed mitochondrial heteroplasmy. The increasing use of invasive techniques in assisted reproduction in humans has raised concerns that one of the outcomes of such techniques is an increase in the incidence of mitochondrial heteroplasmy. Indeed, there is evidence that heteroplasmy is a direct consequence of ooplasm transfer, a technique that was used to 'rescue' oocytes from older women by injecting ooplasm from young oocytes. Mitochondria from donor and recipient were found in varying proportions in resulting children. Heteroplasmy is also a byproduct of nuclear transfer, as has been shown in studies on cloned sheep, cattle and monkeys. As therapeutic cloning will depend on nuclear transfer into oocytes and the subsequent generation of embryonic stem cells from resulting blastocysts, the prospect of mitochondrial heteroplasmy and its potential problems necessitate further studies in this area.
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Yi YC, Chen MJ, Ho JYP, Guu HF, Ho ESC. Mitochondria transfer can enhance the murine embryo development. J Assist Reprod Genet 2007; 24:445-9. [PMID: 17726643 PMCID: PMC3455080 DOI: 10.1007/s10815-007-9161-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Accepted: 07/05/2007] [Indexed: 10/22/2022] Open
Abstract
PURPOSE To evaluate the effect of mitochondrial transfer on embryonic development. MATERIALS AND METHODS Mitochondria concentrates were collected from murine hepatocytes and fertilized murine zygotes from young and older mice in the 2PN stage were subjected to mitochondrial transfer and cultured in vitro to evaluate the embryonic development. RESULTS After extended in vitro culture, 37.65% and 20.91% embryos from the young mice developed to the blastocyst stage in the injected and control groups respectively, which is statistically significant. There was no difference in terms of hatching rates (1.76% and 1.82% respectively). Zygotes from the older mice (>20 weeks old) that received mitochondrial transfer also had a better developmental outcome than the control group (54.35% and 18.92% developed to morula stage, 43.48% and 8.11% developed to the blastocyst stage respectively), which is statistically significant. CONCLUSIONS Our results for the murine model provide direct scientific evidence that mitochondrial transfer improves embryonic development. However, potential risks such as mitochondrial heteroplasmy, nuclear-mitochondrial interaction and epigenetic aspects all deserve further evaluation before mitochondrial transfer is applied clinically.
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Hua S, Zhang Y, Li XC, Ma LB, Cao JW, Dai JP, Li R. Effects of Granulosa Cell Mitochondria Transfer on the Early Development of Bovine Embryos In Vitro. CLONING AND STEM CELLS 2007; 9:237-46. [PMID: 17579556 DOI: 10.1089/clo.2006.0020] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The objective of this study was to determine the effect of exogenous mitochondria obtained from granulosa cells on the development of bovine embryos in vitro. We classified cumulus oocyte complexes (COCs) as good (G)- and poor (P)-quality oocytes based on cytoplasmic appearance and cumulus characteristics, and assessed mtDNA copy numbers in the G and P oocytes with real-time polymerase chain reaction (PCR). The mitochondria were isolated by fractionation and suspended in mitochondria injection buffer (MIB). Part one of the experiment consisted of the following treatments: (1) G-oocytes + sperm, (2) P-oocytes + mitochondria + MIB + sperm, (3) P-oocytes + MIB + sperm, and (4) P-oocytes + sperm. In part 2, oocytes were parthenogenetically activated. The treatments were: (1) G-oocytes, (2) P-oocytes + mitochondria + MIB, (3) P-oocytes + MIB, and (4) P-oocytes alone. The results indicated a significant difference in mtDNA copy number between G (361 113 +/- 147 114) and P (198 293 +/- 174 178) oocytes (p < 0.01). The rates of morula, blastocyst, and hatched blastocysts derived from P-oocytes + mitochondria were similar to those of G-oocytes, but significantly higher than P-oocytes without exogenous mitochondria in both the ICSI and parthenogenetic activation experiments. We found no difference in blastomere numbers between G-oocytes and P-oocytes + mitochondria in either experiment, but blastomere numbers in these two groups were significantly higher than in P-oocyte groups without exogenous mitochondria. These data suggest that mtDNA content is very important for early embryo development. Furthermore, the transfer of mitochondria from the same breed may improve embryo quality during preimplantation development.
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Pinkert CA, Trounce IA. Generation of Transmitochondrial Mice: Development of Xenomitochondrial Mice to Model Neurodegenerative Diseases. Methods Cell Biol 2007; 80:549-69. [PMID: 17445713 DOI: 10.1016/s0091-679x(06)80027-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Bonnefoy N, Remacle C, Fox TD. Genetic transformation of Saccharomyces cerevisiae and Chlamydomonas reinhardtii mitochondria. Methods Cell Biol 2007; 80:525-48. [PMID: 17445712 DOI: 10.1016/s0091-679x(06)80026-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Bongaerts GPA. How to prevent 'half-bastard' progeny? or An alternative for three-parent babies: two-parent babies through transplantation of sperm mitochondria. Med Hypotheses 2006; 67:1266-9. [PMID: 16797857 DOI: 10.1016/j.mehy.2006.04.053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 04/11/2006] [Accepted: 04/12/2006] [Indexed: 11/15/2022]
Abstract
Body development and activity depend on the level of internal energy generation. Therefore, unaffected, optimally active mitochondria are indispensable in a healthy and vital body. A mutation in the DNA of the semi-autonomous mitochondria (mtDNA) may cause an inheritable insufficiency that is due to decreased energy generation needed for adequate development. Sperm mitochondria will not enter the egg cell during fusion of male and female gametocytes. Since women with mutated mtDNA will increasingly know and realize the effect of such mutation in their own body, they will more often ask for treatment to stop the effect of such inconvenient mutation in their progeny. Thus far, solutions for this problem were thought to be: (i) nucleus transplantation just after fertilization into a nucleus-free egg cell of a second healthy woman and later (ii) transplantation of healthy mitochondria from a second woman into the egg cell before fertilization. Although both transplantations create babies with three, instead of two-parents that have contributed to the genetic content, in case of the newer mitochondria transplantation technique the part of the second woman is somewhat more reduced, but still clearly present. Thus, assisted-reproduction techniques that mix egg cell mitochondria from two women may create not only 'three-parents' babies, but also fears for 'three-parents' babies, since this handling may create non-scientific problems, especially regarding emotional, ethical, religious and juridical aspects of life. Transplantation of healthy sperm mitochondria of the partner into the egg cell with insufficient mitochondria is thought to be the best solution for this problem, since it may create a 'two-parents' instead of a 'three-parents' baby. This only implies that at the moment of (successful) transplantation the biological dogma is broken that mitochondria are maternally inherited: the mitochondria of the maternal line of the woman will have been substituted by the mitochondria of the maternal line of the man.
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