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Interview with Prof Laura Rienzi by Dr Jacques Cohen at COGI Amsterdam 2016
Q. Hello, I am Jacques Cohen. We are here in Amsterdam on a lovely, grey day; it is not raining. We are at the COGI meeting. We just finished a very interesting quality control QCQM session in the embryology session of this meeting this morning, and I have with me Laura Rienzi, who gave two terrific talks. There is a lot of response from the audience. What I would like to do is give us the highlights. The first talk was on how to improve the quality in IVF lab. You said a lot of very good things. Give us the highlights.
A. Embryo culture is really a very important part of our job. The success rate is strongly related to the quality of the culture, so it was a very important topic to discuss herewith colleagues. We know that we cannot really improve the quality of the embryo that we generate in our laboratory, but we can make many things that potentially can affect the quality. My talk was taking under consideration the most important factors that can reducethe quality of our embryos during manipulation and culture and that we should minimise stress and how much the embryo is able to react to stress and to compensate to stress. I think that standardization of the culture is necessary to ensure the quality of everywhere.
Q. One thing that was striking for me is you demonstrated with a recent example, a 2016 paper from the Maastricht group, and I am sorry, I just forgot the first author’s last name, but it is the Dumoulin team, comparing one medium that is a sequential system that has been improved over the years, the G5 system, with an old medium,based on the back to nature philosophy called HTF, which has created a lot of babies, but a long time ago. Those are two extreme systems. What is striking to meis that the clinical findings were very different from your conclusions. Can you explain that?
A. When we looked at randomized controlled trials, the high level of evidence is only related to the primary outcome issue. The secondary outcome issue, as in this case,may be affected by different distribution of patients. In this case, because the number of women having a live birth was different in the two groups, and then there was also a different distribution in single and twins, the quality of the evidence related to obstetrical outcomes was very low and under powered, so I don’t think we can conclude with that study about obstetrical outcomes, but it is, of course, interesting to see that the culture system from the beginning of life can have a long term effect on the live birth.
Q. There are so many confounders in all of the studies we do; there is not much we cando about it. Certainly, in this case, sample size becomes important because oftenyou get subgroups, you have no choice in your analysis and so evaluations becomevery complicated and conclusions even more complicated. That was a very good message. Also, it shows that you can’t just read a paper by looking over an abstract, you really have to read the paper. You could come to conclusions that one mediumwas better than the other, and it is not that simple. I think that was beautifully demonstrated. Your second talk follows the same critical line and was, to me, a major event here this morning because, in the second talk, you go into the importance of selecting sperm during ICSI, particularly emphasised IMSI work. What are your conclusion sabout IMSI and selecting sperm, based on morphological criteria?
A. My conclusion about sperm selection is that, to date, we don’t have any validated technology that can improve sperm selection prior to ICSI. More than what was reported in 1992, on the first paper, published by Gianpiero Palermo in the Lancet, but we need a normal appearing motile sperm. We have a lot of evidence that motility and normal appearance is necessary because abnormal one – you cannot find a normal appearing sperm in the ejaculate which reflects also the quality of the spermatogenesis itself, not only the quality of the sperm; this may affect fertilization rates. This was reported by a group of Brussels in 1992. Other than this there is, after 15 years, we don’t have clear evidence, level 1 evidence, in the literature that any technology is helping to improving implantation rate of a deriving embryo and the live birth rate. The take home message that I want to give is that an embryo is a big puzzle. There are many pieces of the puzzle that has a different width and we know that female ageand chromosomal abnormality is a bit piece of the puzzle and female age is the most predictive characteristic of the embryo. The sperm probably is a small piece; I don’t know how small, but it is a small piece. This is why it is very difficult to find evidence by changing the sperm which completely changes the picture. Morphology for sperm, that is true also for oocyte and embryo, is fairly predictive of the intrinsic quality of the cell.
Q. You also, very rightly, pointed out that the emphasis has not just been on morphology but on what we call vacuoles, which you pointed out are vacuole like; maybe you can describe, because this is important and your pictures are very convincing. It is important to describe what are these structures.
A. This is really funny, but in the literature for 15 years we were calling a structure, but itis, in fact, not the real term. I just took a picture from the studies; it is not even my own picture. Studies that are describing nuclear vacuoles in the sperm in fact, if you just look, you don’t even need to read the paper, just look at the pictures, you will see that these kinds of structure are mainly related to the acrosomal region. There are different studies with different microscopy approaches showing that it is invaginationof a membrane. My key message here was first we have to understand what we are looking at. First, we have to have a strong biological background behind the technology and then start obtaining an application. I don’t know if invagination of a membrane is reflecting the quality of the sperm; I am not saying that it is not; it is possible, but it is not a vacuole. It is not related.
Q. It is important; there is little to no cytoplasm in the sperm and the little bit there is in the midpiece. I do think that midpieces are underestimated. I think, particularly the quality of the centriole, which we may not be able to judge based on morphology because it is so tiny and elusive, that probably has an effect on some forms of mosaicism. These recurrent high levels of chaotic mosaicism that you see in the occasional patient and then doing a parallel insemination with donor sperm; I mean there have been some case reports that show that there can be differences there. I do think it has a contribution, but it is very poorly understood.
A. We know that the meiotic contribution of aneuploid sperm is low. We don’t really know what the mechanism related to mitotic aneuploidy was, but generate mosaicism but we know that the impact is quite low in human embryos, but which at this stage;we just have published a paper about the real impact of mosaicism on embryos and I am sure it is a combination of more than one factor in this case, not only the oocyte,but the repairing capacity of the oocyte. It can happen also at two cell stage, four cell stage; I don’t know how much it is still of sperm origin, but nature is very complicated and it is probably a combination of many different factors.
Q. The frequency has always been high, even in the very poor methods, 15/20 years ago. All the publications show the high frequency of mosaicism, it is not now,recently, that it becomes more worrying because of this increased resolution that we have.
A. It also depends on the stage of development where you assess mosaicism, because there is a rate of self-selection when you get to blastocyst very probably.Q. Absolutely yes. In conclusion, your talks clearly indicate that there is so much more when you look over literature, that part of our duty as embryology scientists is to read the literature and do this not in a superficial manner. You showed that very clearly in your talks. There is a lot behind it. Authors have to publish an abstract, they have to;they have to get a capsule message out, but it is very hard to do. You are missin gmajor points sometimes as an author; you want to present it, but you submit the paper and you get the cut off like your 40 words, or 120 words or 300 words over –you have to cut it down to what the electronic system tells you to do, so it is important to look at papers and the minimum at tables and figures and maybe read the discussion.
A. Share the results and discuss like we are doing today. Today I think is really very important.
Q. Very good talking to you.
A. Thank you.
Q. A pleasure.