Researchers isolate high-quality sperm using acoustic waves

Researchers isolate high-quality sperm using acoustic waves

Monash University researchers have combined acoustic waves and fluid dynamics to create a new approach for separating high-quality sperm in assisted reproduction – opening new windows for infertile couples to have a family of their own.

This rapid and automated acoustofluidic process, developed by a team from Monash University’s Department of Mechanical and Aerospace Engineering, can isolate sperm with normal head morphology and high DNA integrity from raw semen samples.

The device can process roughly 140 sperm per second and select more than 60,000 high-quality sperm in under 50 minutes – a clinically-relevant number of sperm to perform IVF (In Vitro Fertilisation) and ICSI (Intracytoplasmic Sperm Injection).

This life-changing research, published in the leading microfluidic journal Lab on a Chip, was led by second-year Ph.D. student Ms Junyang Gai. The work has been supervised by Dr Reza Nosrati and Professor Adrian Neild – experts in microfluidics from the Department of Mechanical and Aerospace Engineering.

The approach isolates sperm from raw semen by applying an acoustic field at a 30° angle to the flow direction. The acoustic forces direct and push high-quality sperm out of the mainstream, across the microchannel and isolates them in a separate outlet, leaving the general population of sperm in the raw sample.”

With the application of SSAW (standing surface acoustic waves) at 19.28 MHz and 1-2W, the acoustic radiation force was large enough to overcome the drag and guide the motile sperm to swim across the microchannel width, while other sperm and debris followed the mainstream flow to be collected from the discarded outlet.

This enabled a continuous, high-throughput, and size-dependent selection process for isolating high-quality sperm.

“Our results demonstrate that the selected sperm population exhibit a considerably higher percentage of progressively motile sperm (83 per cent), than both the initial raw sample (52 per cent) and the discarded subpopulation of sperm (36 per cent),” Ms Gai said.

The result is the selection of sperm with over 60 per cent improvement in progressive motility (the ability for sperm to move independently), while providing a clinically-relevant sample for IVF and ICSI. Sperm selected from this approach also show a near 40 per cent improvement in DNA integrity.

Dr Nosrati says the success rate depends on many different parameters, but ultimately, it is down to the quality of sperm and egg.

“Our process aims to select better sperm within a faster time frame, so hopefully this can lead to improved outcomes in assisted reproduction. When fully tested and implemented, this method could open new windows and opportunities for infertile couples to have a baby,” Dr Nosrati said.

“We hope that with further testing, our acoustofluidic sperm selection process can provide new opportunities and be of benefit to the assisted reproduction industry, and help remove the fear, anxiety and negative stereotypes associated with infertility.”

The infertility rate has increased over the past 50 years, with one in six couples experiencing infertility. Male infertility is responsible for about 30 per cent of cases, with a combination of male and female factors contributing to about half of cases, worldwide.

“Male infertility is a global reproductive issue and several clinical approaches have been developed to tackle it. However, their effectiveness is limited by the labour-intensive and time-consuming sperm selection procedures used,” Dr Nosrati said.

Sperm preparation or selection is a key step in assisted reproduction being performed right before fertilising the egg.

The current clinical process involves multiple washing and centrifugation steps and a manual selection step, and takes up to three hours to complete, which can also be harmful to sperm.”

Professor Neild says the method of sperm selection hasn’t changed much over the past 30 years, selecting sperm mainly based on motility, and as a result, the success rate of assisted reproduction cycles has plateaued at about 33 per cent.

“Our approach also considers sperm size and morphology during the selection process, in addition to sperm motility. With further research, hopefully our approach can improve the outcomes of assisted reproduction and reduce the costs associated with the treatment cycle,” Professor Neild said.

Professor Neild is a world expert in acoustofluidics with many important contributions to the field over the past 15 years. Dr Nosrati is a pioneer in microfluidics for assisted reproduction and has developed technologies for sperm selection and analysis over the past six years.

Read more: https://pubs.rsc.org/en/content/articlelanding/2020/LC/D0LC00457J#!divAbstract

Frozen IVF embryos do not increase chance of pregnancy

Frozen IVF embryos do not increase chance of pregnancy

The use of frozen rather than fresh embryos in IVF does not increase the chance of a successful pregnancy, newly published data shows.

The findings discourage the ‘freeze-all’ strategy adopted by some fertility clinics in recent years. They thought that using frozen embryos rather than immediately transferring fresh embryos to the uterus allows patients’ bodies more time to recover from disruptive hormonal treatment required in IVF and intracytoplasmic sperm injection (ICSI) cycles.

Preliminary results of the randomised, multi-centre trial were reported last year at the European Society for Human Reproduction and Embryology’s annual meeting. Speaking at the meeting, lead author Dr Sacha Stormlund from Hvidovre University Hospital in Copenhagen, Denmark, remarked: ‘I think we can now reasonably say, based on our results and those from other recent trials, that in normally ovulating patients there is no apparent benefit from a freeze-all strategy in IVF.

The study, recently published in the British Medical Journal, analysed 460 IVF and ICSI patients across Denmark, Sweden and Spain.

Participants were aged between 18 and 39, and receiving their first, second or third treatment cycle. Half of participants underwent frozen embryo transfer one month after initial egg harvest, whereas the other half received fresh embryo transfer a few days after harvest.

The researchers found that there was no significant difference between the percentage of women who fell pregnant in each treatment group, 27.8 percent for women who froze their embryos compared with 29.6 percent who underwent fresh embryo transfer. In addition, there was no significant difference between the live birth rates, 27.4 and 28.7 percent for frozen and fresh embryo transfer, respectively.

The study also reported a slightly increased risk of preterm birth in the fresh embryo transfer group. However, time to pregnancy was significantly longer in the frozen embryo transfer cohort, leading the authors to conclude that ‘fresh embryo transfer should be used as the gold standard’.

The findings could influence best practice in fertility clinics and are especially relevant given the enormous rise in frozen embryo transfer cycles in recent years – the Human Fertilisation and Embryology Authority’s (HFEAs) latest figures reported a 93 percent increase between 2013 and 2018.

The authors noted that fresh embryo transfer may not be appropriate for all patients, specifically those at a higher risk of the serious side effect of ovarian hyperstimulation syndrome (OHSS). In these patients, frozen embryo transfer can reduce the risk of OHSS.

Dr Stormlund’s team concluded by recommending that: ‘The findings warrant caution in the indiscriminate application of a freeze-all strategy when no apparent risk of ovarian hyperstimulation syndrome is present.’

Source: https://www.bionews.org.uk/page_151306

High-resolution 4D imaging of sperm cells moving at top speed could improve IVF treatments

High-resolution 4D imaging of sperm cells moving at top speed could improve IVF treatments

Tel Aviv University (TAU) researchers have developed a safe and accurate 4D imaging method to identify sperm cells moving at a high speed.

The new technology could provide doctors with the ability to select the highest-quality sperm for injection into an egg during IVF treatment, potentially increasing a woman’s chance of becoming pregnant and giving birth to a healthy baby.

“The most common type of IVF today is intra-cytoplasmic sperm injection (ICSI), which involves sperm selection by a clinical embryologist and injection into the woman’s egg. To that end, an effort is made to select the sperm cell that is most likely to create a healthy embryo.”, said the head researcher Prof. Shaked.

Under natural fertilization in the woman’s body, the fastest sperm to reach an egg is supposed to bear high-quality genetic material. Progressive movement allows this “best” sperm to overcome the veritable obstacle course of a woman’s reproductive system.

“But this ‘natural selection’ is not available to the embryologist, who selects a sperm and injects it into the egg,” Prof. Shaked says.

“Sperm cells not only move fast, but they are also mostly transparent under regular light microscopy, and cell staining is not allowed in human IVF. Existing imaging technology that can examine the quality of the sperm’s genetic material may cause embryonic damage, so that too is prohibited. In the absence of more precise criteria, sperm cells are selected primarily according to external characteristics and their motility while swimming in water in a dish, which is very different from the natural environment of a woman’s body”.

“In our study, we sought to develop an entirely new type of imaging technology that would provide as much information as possible about individual sperm cells, does not require cell staining to enhance contrast, and has the potential for enabling the selection of optimal sperm in fertilization treatments.”

The researchers chose light computed tomography (CT) technology for the unique task of sperm cell imaging.

“In a standard medical CT scan, the device rotates around the subject and sends out X-rays that produce multiple projections, ultimately creating a 3D image of the body,” says Prof. Shaked. “In the case of the sperm, instead of rotating the device around this tiny subject, we relied on a natural feature of the sperm itself: Its head is constantly rotating during the forward movement. We used weak light (and not X-rays), which does not damage the cell. We recorded a hologram of the sperm cell during ultrafast movement and identified various internal components according to their refractive index. This creates an accurate, highly dynamic 3D map of its contents without using cell staining.”

Using this technique, the researchers obtained a clear and accurate CT image of the sperm at very high resolution in four dimensions: three dimensions in the space at resolution of less than half a micron (one micron equals one millionth of a meter) and the exact time (motion) dimension of the second sub-millisecond.

“Our new development provides a comprehensive solution to many known problems of sperm imaging,” Prof. Shaked says. “We were able to create high-resolution imaging of the sperm head while it was moving fast, without the need for stains that could harm the embryo. The new technology can greatly improve the selection of sperm cells in vitro, potentially increasing the chance of pregnancy and the birth of a healthy baby.

“To help diagnose male fertility problems, we intend to use our new technique to shed light on the relationship between the 3D movement, structure and contents of sperm and its ability to fertilize an egg and produce a viable pregnancy,” Prof. Shaked concludes. “We believe that such imaging capabilities will contribute to other medical applications, such as developing efficient biomimetic micro-robots to carry drugs within the body.”

Read more: http://www.eng.tau.ac.il/~omni/ScienceAdvances2020.pdf


Οι κύστεις στις ωοθήκες υπογόνιμων γυναικών με ενδομητρίωση επηρεάζουν αρνητικά τον αριθμό των ωαρίων και την ποιότητά τους

Οι κύστεις στις ωοθήκες υπογόνιμων γυναικών με ενδομητρίωση επηρεάζουν αρνητικά τον αριθμό των ωαρίων και την ποιότητά τους

Ο πόνος και η υπογονιμότητα είναι τα δύο βασικά συμπτώματα της ενδομητρίωσης. Εκτιμάται ότι οι γυναίκες που πάσχουν από ενδομητρίωση είναι 30-50% πιο πιθανό να είναι υπογόνιμες.

Οι μηχανισμοί της υπογονιμότητας που σχετίζεται με την ενδομητρίωση είναι ακόμα άγνωστοι. Μπορεί να οφείλονται στις εστίες ενδομητρίωσης στις ωοθήκες, στη διαταραχή της ανατομίας της πυέλου, σε ορμονική ανισορροπία ή στη χειρότερη ποιότητα των ωαρίων που παράγουν οι γυναίκες με ενδομητρίωση.

Οι ερευνητές αξιολόγησαν την ποιότητα των ωαρίων σε γυναίκες με υπογονιμότητα που συνδέεται με την ενδομητρίωση και διαπίστωσαν ότι ο αριθμός και η ποιότητα των ωαρίων που παράγουν επηρεάζονται αρνητικά από τις κύστεις των ωοθηκών.

Η ποιότητα των ωαρίων μιας γυναίκας επηρεάζεται ιδιαίτερα όταν μια μεγάλη κύστη των ωοθηκών (ενδομητρίωμα), που μερικές φορές ονομάζεται σοκολατοειδής κύστη, έχει διάμετρο μεγαλύτερη από 3 εκατοστά.

Η χειρουργική αφαίρεση των κύστεων των ωοθηκών δεν αποκαθιστά την ικανότητα των ωοθηκών να παράγουν ωάρια, σύμφωνα με τα αποτελέσματα της μελέτης. “Τα ενδομητριώματα επηρεάζουν αρνητικά τον αριθμό των ωαρίων στην ωοθήκη. Ακόμα και μετά την κυστεκτομή τα ενδομητριώματα έχουν συνεχιζόμενη επιβλαβή επίπτωση στο ωοθηκικό απόθεμα” σύμφωνα με τους ερευνητές.

Γυναίκες αναπαραγωγικής ηλικίας, 29-40 ετών, που υποβλήθηκαν σε εξωσωματική γονιμοποίηση (IVF) ή μικρογονιμοποίση ωαρίων (ICSI) συμμετείχαν στη μελέτη που διεξήχθη μεταξύ 2018 και 2019 από επιστήμονες του Ιατρικού Ινστιτούτου του Πανεπιστημίου RUDN και της Nova Clinic, ενός κέντρου αναπαραγωγής και γενετικής στη Ρωσία.

Οι γυναίκες χωρίστηκαν σε τρεις ομάδες. Η ομάδα 1 περιελάμβανε 50 ασθενείς με επαναλαμβανόμενα ενδομητριώματα. Η ομάδα 2 περιελάμβανε 50 γυναίκες που είχαν υποβληθεί σε χειρουργική αφαίρεση ενδομητριωμάτων. Η ομάδα 3, ομάδα ελέγχου, περιλάμβανε 30 ασθενείς χωρίς ενδομητρίωση, που είχαν υπογονιμότητα σαλπιγγικού παράγοντα.

Η ποιότητα των ωαρίων προσδιορίστηκε σε όλους τους κύκλους IVF / ICSI. Οι ερευνητές αξιολόγησαν τον αριθμό των καταβολών ωαρίων και τα καταμέτρησαν υπερηχογραφικά (antral follicle count AFC). Στη συνέχεια κατέγραψαν τον αριθμό των ωαρίων που συλλέχθηκαν από κάθε γυναίκα και αξιολόγησαν τα κύρια μορφολογικά χαρακτηριστικά τους.

Τα αποτελέσματα της μελέτης έδειξαν ότι και οι δύο ομάδες γυναικών με υπογονιμότητα που σχετίζεται με την ενδομητρίωση είχαν λιγότερες καταβολές ωαρίων, γεγονός που υποδηλώνει ότι οι ωοθήκες έχουν μειωμένη ικανότητα να παράγουν ωάρια σε σύγκριση με την ομάδα ελέγχου. Από τις ωοθήκες των ασθενών με ενδομητρίωση ελήφθησαν συγκριτικά λιγότερα ωάρια.

Η μορφολογική ανάλυση έδειξε ότι οι ασθενείς με ενδομητρίωση παρήγαγαν πιο ανώριμα ωάρια, σε πρώιμα στάδια ανάπτυξης που ονομάζονται μετάφαση Ι ή στο στάδιο βλαστικού κυστιδίου. Αυτές οι γυναίκες παρήγαγαν επίσης λιγότερα καλής ποιότητας ωάρια μετάφασης II, τα οποία είναι ώριμα και έτοιμα για γονιμοποίηση. Το γεγονός αυτό δείχνει μειωμένη ποιότητα ωαρίων. Αυτό παρατηρήθηκε σε γυναίκες με ωοθήκες που είχαν ενδομητριώματα με διάμετρο μεγαλύτερη από 3 εκατοστά.

Η έρευνα έδειξε επίσης ότι 25% των ωαρίων που ελήφθησαν από ωοθήκη η οποία είχε σοκολατοειδή κύστη είχαν δομικές αλλαγές και σημάδια εκφυλιστικών αλλαγών.

Φάνηκε επίσης ότι τα ωάρια που ελήφθησαν από ασθενείς με ενδομητρίωση ήταν πιο δύσκολο να φθάσουν σε στάδιο που να είναι έτοιμα για γονιμοποίηση.

Η μελέτη δημοσιεύθηκε στην επιστημονική επιθεώρηση Gynecological Endocrinology.

Ovarian cysts negatively affect number and quality of eggs in women with endometriosis-associated infertility

Ovarian cysts negatively affect number and quality of eggs in women with endometriosis-associated infertility

Pain and infertility are two main symptoms of endometriosis. It is estimated that women who suffer from endometriosis are 30-50% more likely to be infertile.

The mechanisms of endometriosis-associated infertility are still unknown. It may be caused by the formation of endometrial lesions on ovaries, anatomical distortions in the pelvis, hormonal imbalance or the inferior quality of the eggs.

Researchers assessed the quality of oocytes (eggs) in women with infertility associated with endometriosis and found that the number and quality of eggs they produce are negatively affected by ovarian cysts, thus also affecting the outcomes of assisted reproduction.

The quality of a woman’s eggs is particularly affected when a large ovarian cyst (endometrioma) sometimes called chocolate cyst has a diameter larger than 3 cm.

Surgical removal of ovarian cysts does not restore the ovaries’ capacity to produce eggs, the study suggests. “Endometriomas negatively affect the quality of oocyte and ovarian reserve, whereas endometriomas after cystectomy, have a deleterious and sustained effect on ovarian reserve” according to the researchers.

Infertile reproductive-aged women, between 29 and 40 years who underwent IVF and ICSI procedures participated in the study, conducted between 2018 and 2019 by scientists at the Medical Institute of the RUDN University and Nova Clinic, a center for reproduction and genetics, in Russia.

The women were divided into three groups. Group 1 included 50 patients with recurrent endometriomas, the ovarian cysts related to endometriosis. Group 2 included 50 women who had undergone surgical removal of endometriomas. Group 3, the control group included 30 patients without endometriosis, but who had tubal factor infertility.

Oocyte quality was determined across all IVF / ICSI cycles. The researchers assessed the number of antral follicles (ovarian follicles with the potential to release an oocyte) which were counted by ultrasound. They counted the number of oocytes collected from each woman and evaluated the main morphological characteristics of the oocytes.

The results showed that both groups of women with endometriosis-associated infertility had fewer antral follicles, indicating a lesser ability by the ovaries to produce oocytes, in comparison with the control group. Fewer oocytes were recovered from the ovaries of endometriosis patients.

The morphological analysis further revealed that endometriosis patients produced more immature oocytes -ones at early stages of development called metaphase I or germinal vesicle stage. These women also produced less high-quality oocytes, those in metaphase II, which are ready for fertilization. This indicated a decline in the quality of the oocytes. Such deterioration was observed from ovaries containing larger endometriomas of more than 3 cm in diameter.

Individual analyses demonstrated that 25% of the oocytes extracted from an ovary containing an endometrial cyst had structural changes and various signs of degenerative changes.

At the same time, it was more difficult to induce the maturation of oocytes in the lab to a stage they are ready for fertilization when they were collected from endometriosis patients.

The study, “Oocyte quality in women with infertility associated endometriosis” was published in the journal Gynecological Endocrinology.


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