Clinical implications of mitochondrial DNA quantification on pregnancy outcomes: a blinded prospective non-selection study
Clinical implications of mitochondrial DNA quantification on pregnancy outcomes: a blinded prospective non-selection study
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DOI：
10.1093/humrep/dex292
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发表时间：
2017-11-01
影响因子：
6.1
通讯作者：
Wells, Dagan
中科院分区：
文献类型：
--
作者：
Fragouli, Elpida;McCaffrey, Caroline;Wells, Dagan
研究问题：定量测定滋养外胚层(TE)活检样本中的线粒体DNA(MtDNA)能否提供有关胚泡存活的信息，潜在地增强胚胎选择和改善体外受精治疗结果？摘要回答：这项研究表明，形态良好但mtDNA水平高的整倍体胚泡着床潜力大大降低。已知：有必要采用更好的胚胎选择方法来改善体外受精结局，因为移植高形态级别的染色体正常胚胎不能保证持续妊娠。胚胎细胞中线粒体DNA的数量被认为是一种新的活性生物标志物--更高水平的线粒体DNA与着床潜力降低相关。研究设计、大小、持续时间：对199个胚泡的线粒体DNA进行了量化，这些胚泡之前被活检，并通过植入前非整倍体遗传学测试(PGT-A)证明是染色体正常的。这些是由174对夫妇(平均女性年龄37.06岁)产生的。所有患者均在同一诊所接受体外受精。这项研究是以盲目、非选择的方式进行的--即单胚胎移植时mtDNA的数量尚不清楚。随后将移植的胚胎的命运与测量的mtDNA水平进行比较。PARTICIPANS/材料、背景、方法：胚胎在囊胚阶段进行活检。获得的TE样本进行全基因组扩增，然后通过下一代测序进行全面的染色体分析。同样的活检标本也用定量聚合酶链式反应进行了检测，从而实现了高精度的线粒体DNA定量。在胚泡移植后，用于致盲的密码被破译，并进行分析以揭示mtDNA的数量是否与胚胎植入有关。MAIN结果和偶然性的作用：对199个囊胚的mtDNA分析显示，9个(5%)含有异常高水平的mtDNA。所有胚胎移植都涉及单个染色体正常、形态良好的囊胚。其中121例(60%)导致持续妊娠，11例(6%)导致生化妊娠，10例(5%)自然流产。所有这些囊胚(100%)的mtDNA水平都被认为是正常/低的。其余57枚(29%)胚泡着床失败。在这些不能存活的胚胎中，有9个(16%)的mtDNA水平异常高。这意味着形态良好、整倍体囊胚、线粒体DNA正常/低水平的持续妊娠率为%(121/190)。相比之下，同类型胚胎的持续妊娠率为0/9(0%)，但线粒体DNA水平升高。这一差异在统计学上具有高度显着性(P<；0.0001)。有限的谨慎理由：为了确定任何临床益处的真实程度，必须进行随机临床试验。需要研究来提高对线粒体DNA扩增生物学的理解。研究结果的广泛意义：这是第一次以前瞻性盲法评估线粒体DNA扩增的临床影响的研究。结果证实，mtDNA升高的胚胎很少植入，支持将其用作生存能力生物标记物。线粒体DNA正常/低的整倍体囊胚的植入比例为%，而队列整体的植入比例为60%。研究资金/竞争兴趣(S)：本研究得到了机构资金的支持(英国生殖遗传学和生殖遗传学)。DW得到了国家卫生研究所(NIHR)牛津生物医学研究中心计划的支持。两位作者都没有任何相互竞争的兴趣。
STUDY QUESTION: Can quantification of mitochondrial DNA (mtDNA) in trophectoderm (TE) biopsy samples provide information concerning the viability of a blastocyst, potentially enhancing embryo selection and improving IVF treatment outcomes?SUMMARY ANSWER: This study demonstrated that euploid blastocysts of good morphology, but with high mtDNA levels had a greatly reduced implantation potential.WHAT IS KNOWN ALREADY: Better methods of embryo selection leading to IVF outcome improvement are necessary, as the transfer of chromosomally normal embryos of high morphological grade cannot guarantee the establishment of an ongoing pregnancy. The quantity of mtDNA in embryonic cells has been proposed as a new biomarker of viability-higher levels of mtDNA associated with reduced implantation potential.STUDY DESIGN, SIZE, DURATION: mtDNA was quantified in 199 blastocysts, previously biopsied and shown to be chromosomally normal using preimplantation genetic testing for aneuploidy (PGT-A). These were generated by 174 couples (average female age 37.06 years). All patients underwent IVF in a single clinic. The study took place in a blinded, non-selection manner-i.e. mtDNA quantity was not known at the time of single embryo transfer. The fate of the embryos transferred was subsequently compared to the mtDNA levels measured.PARTICIPANTS/MATERIALS, SETTING, METHODS: Embryos were biopsied at the blastocyst stage. The TE samples obtained were subjected to whole genome amplification followed by comprehensive chromosome analysis via next generation sequencing. The same biopsy specimens were also tested using quantitative PCR, allowing highly accurate mtDNA quantification. After blastocyst transfer, the code used for blinding was broken and analysis undertaken to reveal whether the amount of mtDNA had any association with embryo implantation.MAIN RESULTS AND THE ROLE OF CHANCE: mtDNA analysis of the 199 blastocysts revealed that 9 (5%) contained unusually high levels of mtDNA. All embryo transfers involved a single chromosomally normal blastocyst of good morphology. Of these, 121 (60%) led to ongoing pregnancies, 11(6%) led to biochemical pregnancies, and 10 (5%) spontaneously miscarried. All (100%) of these blastocysts had mtDNA levels considered to be normal/low. The remaining 57 (29%) blastocysts failed to implant. Among these non-viable embryos there were 9 (16%)with unusually high levels of mtDNA. This meant that the ongoing pregnancy rate for morphologically good, euploid blastocysts, with normal/low levels of mtDNA was 64% (121/190). In contrast, the ongoing pregnancy rate for the same type of embryos, but with elevated mtDNA levels, was 0/9 (0%). This difference was highly statistically significant (P < 0.0001).LIMITATIONS REASONS FOR CAUTION: To determine the true extent of any clinical benefits a randomized clinical trial will be necessary. Research is needed to improve understanding of the biology of mtDNA expansion.WIDER IMPLICATIONS OF THE FINDINGS: This is the first investigation to evaluate the clinical impact of increased mtDNA in a prospective blinded manner. Results confirm that embryos with elevated mtDNA rarely implant, supporting its use as a viability biomarker. A total of 64% of euploid blastocysts with normal/low mtDNA implanted versus 60% for the cohort as a whole.STUDY FUNDING/COMPETING INTEREST(S): This study was supported by institutional funding (Reprogenetics UK and Reprogenetics). DW is supported by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre Programme. None of the authors have any competing interests.