Fertility News

Light from devices at night affects sperm quality

Light from devices at night affects sperm quality

Men might want to think twice before reaching for their smartphone at night. A new study found correlations between electronic media use at night and poor sperm quality.

Preliminary results show that greater self-reported exposure to light-emitting media devices in the evening and after bedtime is associated with a decline in sperm quality.

Sperm concentration, motility and progressive motility — the ability of sperm to “swim” properly — were all lower, and the percentage of immotile sperm that are unable to swim was higher, in men who reported more smartphone and tablet usage at night.

Smartphone and tablet use in the evening and after bedtime was correlated with decline in sperm quality. Furthermore, smartphone use in the evening, tablet use after bedtime, and television use in the evening were all correlated with the decline of sperm concentration,” said principal investigator Amit Green, PhD, head of research and development at the Sleep and Fatigue Institute at the Assuta Medical Center in Tel-Aviv, Israel.

“To the best of our knowledge, this is the first study to report these types of correlations between sperm quality and exposure time to short-wavelength light emitted from digital media, especially smartphones and tablets, in the evening and after bedtime.”

The researchers obtained semen samples from 116 men between the ages of 21 and 59 years who were undergoing fertility evaluation. Participants completed questionnaires about their sleep habits and use of electronic devices.

The study also found a correlation between longer sleep duration and higher sperm total and greater progressive motility. In contrast, greater sleepiness was associated with poorer sperm quality.

The research abstract was published recently in an online supplement of the journal Sleep for Virtual SLEEP 2020. SLEEP is the annual meeting of the Associated Professional Sleep Societies, a joint venture of the American Academy of Sleep Medicine and the Sleep Research Society.

Read more: https://academic.oup.com/sleep/article-abstract/43/Supplement_1/A12/5847498?redirectedFrom=fulltext

Partner selection ultimately happens in the woman’s reproductive tract

Partner selection ultimately happens in the woman’s reproductive tract

The female reproductive tract has the final say in human mate choice, according to new research from the University of Eastern Finland.

Achieving pregnancy has been shown to be more likely between partners who carry dissimilar human leucocyte antigen (HLA) immune genes.

Accordingly, humans are expected to choose HLA dissimilar reproductive partners.

Earlier studies have demonstrated that HLA dissimilarity preferences are mediated either by body odours or facial preferences.

However, it has been unclear whether HLA-based mating preferences could occur after sexual intercourse in the female reproductive tract. Researchers at the University of Eastern Finland have now shown that the women’s reproductive tract is capable of mediating post-mating sexual selection (known as the “cryptic female choice”) towards the sperm of HLA dissimilar men.

This indicates that the ultimate mating bias towards genetically compatible partners occurs only after mating, at the gamete level.

The researchers conducted two experiments, where they activated sperm from multiple men with follicular fluid (the oocyte surrounding bioactive liquid) or cervical mucus from several different women.

Then they examined sperm motility and other functionally important physiological changes of sperm in all possible male-female combinations. All the participants were also genotyped for their Human Leucocyte Antigen (HLA) class I and II alleles.

In both studies, the results showed that the fertilisation capability and viability of sperm are strongly dependent on the male-female combination.

In other words, women’s reproductive secretions had a stronger effect on the performance of some males than others. Both datasets also showed that the sperm performance was better in HLA dissimilar male-female combinations than in HLA similar males and females.

Together, the results indicate that the fertilisation capability of sperm is dependent on the immunogenetic compatibility of the reproductive partners and that the fusion of the gametes may be a highly selective process.

“These findings can have important implications for a deeper understanding of sexual selection and the fertilisation process in humans and other mammals,” Associate Professor Jukka Kekäläinen from the University of Eastern Finland says.

“Since the gametes of some partners may be immunologically more compatible than others, our results may also open up novel possibilities for the development of more accurate infertility diagnostics,” Annalaura Jokiniemi, MSc, adds.

Source: https://www.sciencedaily.com/releases/2020/08/200819094748.htm

Read more: https://royalsocietypublishing.org/doi/10.1098/rspb.2020.1682

https://www.nature.com/articles/s41437-020-0350-8

New male fertility test offers clarity for couples struggling to conceive

New male fertility test offers clarity for couples struggling to conceive

Infertility affects 10% to 15% of couples globally, and while often viewed as a women’s health problem, men contribute to around half of the cases.

A new male fertility test based on Cornell research could help predict which men might need treatment and which couples might have success with different forms of assisted reproduction.

“The ‘Cap-Score test is designed to provide information on the man’s fertility that they never had before,” said Dr. Alexander Travis, professor of reproductive biology at the Baker Institute for Animal Health and the test’s inventor.

“Now, doctors can discuss these results with the couple, and help them choose the personalized treatment pathway that is right for them to try to get pregnant, including how to improve the man’s fertility.”

The research was published in Reproductive BioMedicine Online. Travis is senior author.

The Cap-Score is a diagnostic test approved for use by medical doctors in all 50 states; the technology has been licensed to Androvia LifeSciences, LLC, a fertility research company co-founded by Travis, its chief science officer, in 2015. Travis holds equity in the company.

Cap-Score quantifies the ability of sperm to undergo a process called “capacitation,” which enables the sperm to fertilize an egg. Only sperm that capacitate are capable of fertilizing. By contrast, traditional male fertility exams rely primarily on semen analysis, which counts sperm and assesses whether they swim and look normal.

“Fertility exists in degrees; as long as a man produces some sperm that swim, he has some level of fertility,” Travis said. “But it is the functional ability of those sperm to fertilize an egg that influences the odds that a couple will become pregnant.”

The new research included prospective clinical pregnancy outcomes data from six fertility clinics. Prospective tests are important when evaluating a new diagnostic procedure because they show the ability to predict what will happen for patients.

Travis said Cap-Score‘s predictive ability “held true across different age ranges for the female partner.” This is important because there are many well-known impacts of maternal age on a couple’s fertility. The new data shows that the man’s fertility plays a key role in whether a couple will be able to conceive, even if they might have delayed having children and are older.

The researchers also compared Cap-Score results from more than 2,000 men having fertility exams at 22 clinics against results from a control group of fertile men with a pregnant partner or young baby. Cap-Scores from the fertile men showed an expected bell-shaped curve. In contrast, the vast majority of men questioning their fertility had scores below the mean of the fertile population.

Additionally, the researchers examined the relationship between traditional semen analysis results and impaired capacitation. “Men are often assumed to be fertile if they have enough normal-looking sperm that swim,” Travis said, “but we found that almost two-thirds of the men who had low Cap-Scores passed the traditional semen analysis.”

Infertility and most male infertility cases remain unexplained due to a lack of diagnostic testing. Not only does this place the onus of expensive and often invasive testing on women, it also may prompt couples to try expensive procedures that might be inappropriate for their situation. The Cap-Score can now provide crucial missing information to help guide their choices.

“Couples and doctors have had to make important decisions about their fertility without all the information they needed. This has caused a lot of anxiety and pain — physically, financially and emotionally,” Travis said.

Using the Cap-Score, doctors and couples can make informed decisions about whether to try to conceive unassisted or choose one of several medical approaches. The results can also be used to identify which men might benefit from treatment to improve their fertility, including changes in lifestyle, nutritional supplements or surgery.

Read more: https://www.rbmojournal.com/article/S1472-6483(20)30162-0/pdf

Coronavirus transmitted to newborn through mother’s placenta

Coronavirus transmitted to newborn through mother’s placenta

Pregnant women infected with COVID-19 may pass on the disease-causing virus to their baby through the placenta, researchers in France suggest.

In their study, published in Nature Communications, the authors describe the case of a newborn child which presented with SARS-CoV-2 infection shortly after birth and subsequently suffered neurological conditions consistent with symptoms seen in adults with COVID-19.

Through analysis of the blood of mother and child as well as placenta and amniotic fluid, they give strong evidence for the virus to have been transmitted by the infected mother through the placenta. Scientists hope that taken together with other case reports, this could give indications for the risk and impact of COVID-19 infections during pregnancy.

‘This case study is indeed an important addition to the existing literature,’ commented Dr Ela Chakkarapani from the University of Bristol, who was not involved in the study. ‘Data to date has been suggesting in utero transmission may be occurring and this study adds data to further support that.’

In March 2020, the pregnant woman was hospitalised in Paris with symptoms of COVID-19 and tested positive for the virus. Despite immediate isolation after being born by caesarean section, the newborn boy developed neurological symptoms quickly – including distress and muscle spasms – which mirrored COVID-19-related effects in adults. With his health improving soon after, the baby and his mother recovered and were discharged from the hospital.

The authors conclude that based on their analysis of blood, amniotic fluid and placenta, transmission of the virus via the placenta was very likely in the reported case. This adds fire to the ongoing medical debate over the likelihood of an elevated risk of coronavirus infection for expectant mothers and their children, especially in the context of placenta-transmitted disease. According to the CDC, the major source of transmission to babies is contact with respiratory droplets from mothers or other caregivers immediately after birth.

‘It remains rare for babies to become infected; in 244 live-born babies of infected mothers in the UK, 95 percent had no sign of the virus, and outcomes are similar to non-infected babies,’ commented Professor Andrew Shennan from King’s College London. ‘This report adds knowledge to a possible mechanism of transfer to the baby, i.e, via the placenta while pregnant, but women can remain reassured that pregnancy is not a significant risk factor for them or their babies with COVID-19.’

Read more: https://www.nature.com/articles/s41467-020-17436-6

Bioengineering repairs uterus resulting in live births in rabbits

Bioengineering repairs uterus resulting in live births in rabbits

Researchers looking for an alternative to uterus transplants successfully restored uterine structure and function in rabbits using bioengineered uterine tissue.

The research, published in Nature Biotechnology, showed that the engineered tissue developed native tissue-like structures and was able to support pregnancies leading to live births.

‘The study shows that engineered uterine tissue is able to support normal pregnancies, and fetal development was normal,’ said author Professor Anthony Atala from the Wake Forest Institute for Regenerative Medicine in North Carolina. ‘With further development, this approach may provide a pathway to pregnancy for women with an abnormal uterus‘.

In the study, 78 rabbits were randomly assigned to four different groups: groups one to three had most of their uterine tissue removed. Group four was a normal control group, where animals underwent a sham surgery but no tissue was removed.

In group one the excision was repaired with a synthetic polymer scaffold containing cells collected from the tissue that was removed; group two underwent repair with the polymer scaffold only; in group three no extra material was added and the remaining edges were stitched together.

The polymer scaffolds degraded after three months. At six months the group that had repair with the scaffold only developed a thin uterine wall, but the group that received the scaffold seeded with cells had developed native tissue-like structures including distinct endometrium and myometrium tissue layers, and were expressing progesterone and oestrogen hormone receptors. The excision-only group formed scar tissue.

The rabbits were mated naturally with fertile males six months after the procedures. Four out of ten rabbits from the tissue-engineered group had normal PREand gave birth to healthy offspring with normal body weights. No fetal development occurred in the scaffold-only or excision-only groups.

‘This is a highly significant finding with great potential for future human application. For women who suffer infertility due to a severely damaged uterus or because of a hysterectomy then adaptations of this approach may well find clinical application,’ said Professor Darren Griffin from the University of Kent, who was not involved in the study.

Uterus transplantation became a viable treatment following the first successful transplant which led to a live birth in 2014. However, this treatment is associated with a range of issues including lack of donors, transplant rejection and the risk of disease transmission. Bioengineered uteri could be an alternative treatment method for women with uterine infertility; however, more preclinical studies need to be carried out before clinical trials can be performed in humans.

Read more: https://www.nature.com/articles/s41587-020-0547-7

Response to stimulation in IVF may predict longer term health risks

Response to stimulation in IVF may predict longer term health risks

Low ovarian reserve with few eggs collected associated with a higher risk of chronic disease.

A follow-up study of almost 20,000 young women who had a first cycle of IVF in Denmark between 1995 and 2014 indicates that those who responded poorly to treatment, with few eggs collected, are at a significantly increased risk of later age-related diseases.

The findings, according to investigator Mette Wulf Christensen from Aarhus University in Denmark, suggest an “association with early ovarian ageing and an accelerated ageing process in general.”

The results, she explains, are consistent with what we know so far about early menopause, which has been shown in several studies to be associated with an increased risk of cardiovascular diseases, osteoporosis and mortality.

Identifying women at risk of early menopause may thus allow early preventive health initiatives in terms of a healthy lifestyle,” says Christensen.

This is the first time that the yield of eggs in IVF as a measure of ovarian ageing — and thus as a risk predictor of age-related ill-health and mortality — has been investigated in a large-scale cohort study. The results were presented online by Ms Christensen, a PhD student, at the virtual Annual Meeting of ESHRE.

The study was based on the national registries of Denmark in which each individual has their own identifying number, thus allowing cross-linkage between various registries of health outcomes and treatments.

In this case women below the age of 37 who had a first cycle of IVF or ICSI in Denmark between 1995 and 2014 were divided into one of two groups according to their response to ovarian stimulation: those who had produced five or fewer eggs for collection, defined as “early ovarian ageing“; and those who responded normally with at least eight eggs. The number of eggs harvested was thus used as a marker of ovarian reserve. There were 1,234 women in the former group, and 18,614 in the latter.

During the six-year average period of follow-up, the incidence of chronic disease in the two groups was analysed from the cross-linked registry data, providing a real-life estimate of risk for cardiovascular disease, osteoporosis, type-2 diabetes, cancer, and all-cause mortality.

Results showed that women in the early ovarian ageing group had an increased overall risk (by 26%) of all-cause disease when compared to those with a normal ovarian response. This higher risk was statistically significant, and evident in cardiovascular diseases (39% higher) and osteoporosis (more than double).

The two groups were also cross-checked with the “early retirement benefit” register, in which the early ovarian ageing group were also more likely to be listed.

The risk of cancer, other age-related diseases and all-cause death was not significantly different.

Commenting on the implications of the results, Ms Christensen said that, although the common biological mechanisms behind ovarian and general ageing are “somewhat obscure,” the data from this study demonstrate that young women with early ovarian ageing — defined as low oocyte output after FSH stimulation — have an increased risk of age-related morbidity and possibly mortality, “and strongly support the hypothesis that low ovarian reserve may be a useful marker of later health problems.”

Counseling this group of patients at fertility clinics, she added, “may, therefore, be important for introducing preventive measures such as lifestyle changes or the use of HRT to reduce the adverse health risks which follow an earlier menopause.”

Source: European Society of Human Reproduction and Embryology.

Fertility preservation is effective in female cancer patients

Fertility preservation is effective in female cancer patients

The largest study looking at long-term outcomes of fertility preservation in female cancer patients has demonstrated how successful it can be, in particular for breast cancer patients.

The research, presented at the virtual meeting of the European Society of Human Reproduction and Embryology 2020 followed 879 young female patients (mean age 33.8) over a period of 19 years (2000-2019) – the longest reported follow-up of fertility preservation in cancer patients.

‘Currently, there is limited long-term outcome data [on fertility preservation] and this makes it difficult to counsel patients about the likelihood of success.’ said study author Dr Dalia Khalife from Guy’s and St Thomas’ Hospital, London. ‘Our study offers the largest cohort and longest follow-up of fertility preservation in female cancer patients… Around one in six of those who stored their gametes had a good outcome.’

However, she noted that there is a need for longer follow-up of patients and that early referral for fertility treatment is vital.

After counselling, 373 patients (42 percent) chose to have fertility preservation using one of three fertility preservation techniques: egg freezing (53 percent), embryo freezing (41 percent) and ovarian tissue cryopreservation (1%); with 5% using both egg and embryo freezing.

A total of 61 patients (16.4 percent) returned to use their eggs and 44 of them were successful following fertility treatment (live birth rate 72.1 percent).

Women diagnosed with breast cancer were the most likely to return for treatment and also had the highest live birth rate (70 percent versus 30 percent for lymphoma patients).

‘A fertility preservation service must be integral to a modern cancer care pathway. Fertility preservation with eggs and embryos has been beyond experimental for some time. And it’s important that clinicians across the world continue to collect and share data on long-term outcome for all methods, including ovarian tissue preservation, to provide patients with robust information’ said Dr Khalife.

Commenting on the study, Dr Melanie Davies, consultant obstetrician and gynaecologist at University College London Hospitals NHS trust and chair of Fertility Preservation UK, :

‘This is fantastic news – proof positive that fertility preservation is effective and worthwhile. It gives excellent outcomes for those women who return to use frozen eggs/embryos, as 44 of 61 achieved successful pregnancies and births. The proportion of patients who came back to the fertility clinic to use their frozen eggs/embryos (16 percent) is notably higher than for men who store sperm. More will return as the years pass. These results confirm that young women with a new diagnosis of cancer should be offered fertility preservation as part of their treatment pathway as long as they are well enough and time allows.’

Read more: https://www.eshre.eu/ESHRE2020/Media/2020-Press-releases/Khalife

Female hormone in hair could predict response to ovarian stimulation for IVF

Female hormone in hair could predict response to ovarian stimulation for IVF

The prospect of a non-invasive test of ovarian reserve is a little closer following results from a study showing that measurement of a fertility hormone can be accurately taken from a sample of human hair.

Anti-Mullerian hormone — or AMH — has become a key marker in the assessment of how women may respond to fertility treatment.

The hormone is produced by small cells surrounding each egg as it develops in the ovary, and is thus seen as a measure of ovarian reserve. Although studies have not correlated AMH levels to a reliable chance of live birth (nor to forecasting the time of menopause), AMH measurement has become an intrinsic marker in assessing how a patient will respond to ovarian stimulation for IVF — as a normal responder, poor responder (with few eggs), or over-responder (with many eggs and a risk of ovarian hyperstimulation syndrome, OHSS).

AMH is presently measured in serum taken from a blood sample drawn intravenously. The readings represent a measurement at a short moment in time and are relatively invasive to complete.

Now, a new study presented at the online Annual Meeting of ESHRE has tested the quantification of AMH from human hair and found it to be a less invasive and a “more appropriate representation of hormone levels” than from an “acute” source like serum.

The results are presented this week in a poster from PhD student Sarthak Sawarkar, working in the laboratory of Professor Manel Lopez-Bejar in Barcelona, with collaborators from MedAnswers Inc in the USA.

The study, which still continues, now reports results from 152 women from whom hair and blood samples were routinely collected during hospital visits. AMH measured in serum from the same subjects was used to provide a control, as was an ultrasound count of developing follicles in the ovary (AFC) as a further measure of ovarian reserve.

“Biologically relevant” AMH levels were successfully detected in the hair samples, with levels declining with patient age, as expected. As ovarian reserve declines with age, so do AMH levels. The AMH levels from hair strongly correlated with both serum levels and AFC.

It was also seen that the hair test was able to detect a wide range of AMH levels within individuals from a similar age cohort, suggesting a greater accuracy than from a single blood sample.

Hormones accumulate in hair shafts over a period of months, while hormone levels in serum can change over the course of hours.

“So hair,” explain the authors, “is a medium that can accumulate biomarkers over several weeks, while serum is an acute matrix representing only current levels. While hormone levels in blood can fluctuate rapidly in response to stimuli, hormone levels measured in hair would represent an accumulation over several weeks. A measurement using a hair sample is more likely to reflect the average hormone levels in an individual.”

Among the other advantages of a hair test, the authors note that hormone levels are assessed non-invasively, which reduces testing stress and offers a less expensive assay. Testing can be done without visiting a clinic, and thus makes this type of test available to a broader range of women.

“Finally,” explains Mr Sawarkar, “as hair offers a look at the long-term accumulation of hormones, this measurement may allow a better understanding of an individual’s hormone levels — unlike blood-based assays, which can only measure the hormone at the moment of the testing.”

AMH has so far had an important — though sometimes controversial — role in reproductive medicine. Thus, while its role as a measure of ovarian reserve in predicting response to ovarian stimulation for IVF now seems beyond question, there has been doubt over its broader application as a measure of female fertility in the general population.

Commenting on the biology of the test, Mr Sawarkar explains that hormones are incorporated into the matrix of hair before the growing hair reaches the skin surface, thereby allowing an accumulating measurement of hormone concentration.

Story Source: European Society of Human Reproduction and Embryology

Embryo vitrification is safe but longer storage reduces chances of pregnancy success

Embryo vitrification is safe but longer storage reduces chances of pregnancy success

Freezing and storing embryos during fertility treatment using a technique called vitrification is safe, although women are less likely to become pregnant and have a live birth the longer the embryos are stored, according to new research published in Human Reproduction, one of the world’s leading reproductive medicine journals.

There have been concerns that vitrification technology could be unsafe for the embryo, leading to complications at the time of birth and later, including preterm birth, low or high birthweight and birth defects.

Until now, it was also unclear whether storage time after vitrification affected embryo viability, pregnancy outcomes or neonatal outcomes. The study, which is the largest to investigate these questions, found that the chances of becoming pregnant and giving birth to a live baby significantly decreased with longer storage time.

The researchers from the Shanghai Ninth People’s Hospital (Shanghai, China) analysed outcomes from 24,698 patients who had vitrified embryos transferred for the first time between January 2011 and December 2017.

They compared patients who had vitrified embryos stored for up to three months (group one) with patients whose embryos were stored for 3-6 months (group two), 6-12 months (group three) and 12-24 months (group four). They found that the implantation rate fell from 40% in group one to 26% in group four; the clinical pregnancy rate fell from 56% in group one to 26% in group four; and the live birth rate fell from 47% in group one to 26% in group four.

This means that among women who had embryos stored for less than three months, 47 out every 100 women would achieve a live birth. Whereas among women who had embryos stored for between 12-24 months, 34 out of every 100 women would achieve a live birth.

The rate of miscarriages and ectopic pregnancies also increased with longer storage time. However, these associations were not statistically significant after taking into account factors that could affect the results such as the mother’s age, mother’s body mass index, the cause of infertility, parity and embryo quality and stage of development. There was no evidence that storage time affected neonatal outcomes.

Groups three and four had a greater proportion of older women or patients with a poor prognosis due to smaller numbers of available eggs than groups one and two; so the researchers carried out a second analysis to investigate whether it could be the women’s ages and the amount of viable eggs they had in their ovaries at the time of vitrification and embryo transfer that led to the lower pregnancy and birth rates.

They analysed a subset of 7,270 women who were younger than 36 years and whose infertility was caused by blocked or damaged fallopian tubes. This produced similar results; there was a 50% live birth rate among women in group one, compared to a 38% live birth rate in group four.

Dr Qianqian Zhu is a research assistant who led the study. She said: “We think the results from this sub-analysis support our main results about the relationship between the duration of storage with pregnancy and neonatal outcomes.”

Co-author, Professor Qifeng Lyu is deputy director of the department of assisted reproduction at the hospital. He said: “Our study suggests that although the storage time of vitrified embryos negatively affected pregnancy outcomes, including clinical pregnancy and live birth rates, it did not affect neonatal outcomes. Concerns have arisen over the safety of prolonged storage time of vitrified embryos worldwide following the wide application of vitrification, and neonatal health is related to growth, development and health in childhood, adolescence and adulthood. Our study demonstrated the safety of using long-stored embryos after vitrification on neonatal health.

This is reassuring news for couples seeking fertility treatment. The reduction in live birth rates can be overcome through additional embryo transfer cycles. If we had found that neonatal health was adversely affected by vitrification, it would impose a heavy burden on individuals, family and society.”

The study is unable to show the effect of storing embryos for longer than 24 months, and the researchers did not undertake long-term follow-up of babies, so do not have information about their growth and development. As the study was retrospective, the researchers say that prospective studies with long-term follow-up are needed to investigate the safety of vitrification for longer periods of time.

Dr Zhu said: “Our results suggest that clinicians should consider the effect of storage duration before making decisions about the numbers of embryos to freeze and store. This is especially important for cancer patients, who may have their ovaries destroyed by cancer therapies and who have to delay fertility treatment until they have recovered from their disease.”

Vitrification involves placing embryos briefly in a solution to dehydrate them before they are rapidly frozen into a glass-like state. Chemicals called cryoprotectants are used during this process to prevent ice crystals forming, which could damage the embryos. Then the embryos are immediately exposed to liquid nitrogen to freeze them rapidly, ready for storage. When needed, this process is reversed to thaw and warm the embryos quickly. Vitrification is a simple, fast and inexpensive technique, which has become a fundamental tool in fertility treatments in recent years because of its higher embryo survival rates and better clinical outcomes.

Read more: https://academic.oup.com/DocumentLibrary/humrep/PR_Papers/deaa136.pdf

Sperm alterations caused by obesity are not detected in traditional tests

Sperm alterations caused by obesity are not detected in traditional tests

An analysis of sperm from men who were part of a couple whose partner was undergoing in-vitro fertilization (IVF) identified differences in samples between obese vs nonobese men. Specifically, there were differences in the levels of 27 proteins contained in the sperm.

Importantly, all 10 men in these infertile couples (5 obese men and 5 nonobese men) had clinically normal semen, lead study author Taylor Pini, PhD, a postdoctoral scientist at the Colorado Center for Reproductive Medicine, Lone Tree, Colorado said.

That is, the men all had normal sperm concentration, motility, morphology, and DNA fragmentation, which indicates that “these changes in obese men with no overt andrological diagnosis…suggest that traditional clinical semen assessments fail to detect important biochemical changes in spermatozoa which may compromise fertility,” the authors write.

The researchers identified 2034 sperm proteins, of which 24 were significantly less abundant and 3 were more abundant in the obese men than in the men with a healthy weight (P < .05 for both).

The sperm proteins that were less plentiful in the obese men are involved in oxidative stress, inflammation, protein translation, DNA damage repair, and sperm function, and those that were more plentiful are involved in oxidative stress.

“These results suggest that oxidative stress and inflammation are closely tied to reproductive dysfunction in obese men,” the researchers concluded.

These processes likely impact protein translation and folding during spermatogenesis, leading to poor sperm function and subfertility.

Pini noted that “a lot more emphasis has been placed on female as opposed to male obesity” in couples going for infertility work-up, “but I think it is worth considering on the male side as well.”

“It would be worth counseling patients, especially in the very early stages of trying to conceive, that overall health and particularly things like obesity are really worth considering prior to conception,” she emphasized.

The study was published online in the Journal of Assisted Reproduction and Genetics.

An estimated 38% of men of reproductive age (20 to 59 years) in the United States have obesity (body mass index [BMI] ≥30 kg/m2), Pini and colleagues note.

However, it is unclear how obesity may affect male fertility on a molecular level.

Previous studies of sperm proteins in obese men either used a less sensitive method (two-dimensional difference gel electrophoresis), or the more sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) but with a very small sample (3 men) including men with diabetes or smokers.

Pini and colleagues identified 5 obese men (BMI ≥ 30 kg/m2) and 5 non-obese men (BMI ≤ 25 kg/m2) seen at their reproductive medicine center who had clinically normal semen and did not smoke or have diabetes.

They collected semen samples from the men on the day of the oocyte retrieval in the men’s partners, and they used LC-MS/MS to determine the protein content of the sperm.

The control patients had a mean BMI of 24, and the obese patients had a mean BMI of 33. On average, the men in each group were 39 years old (range 33 to 46).

Obese and nonobese men had similar rates of average sperm concentration (88 x 106), total motility (62%), normal morphology (2.9%), and DNA fragmentation (3.3%).

Among the 27 proteins with altered abundance in obese vs normal-weight men, some were involved in oxidative stress (5), inflammation (2), protein translation (3), DNA damage repair (1), and sperm function (3).

The LC-MS/MS findings were confirmed for several proteins by qualitative immunofluorescence and a quantitative protein immunoassay.

“We have shown that obesity significantly impacts the human sperm proteome, potentially to the detriment of important spermatogenic processes and the function of mature spermatozoa,” the researchers report.

“These changes may be both symptoms of, and contributors to, the inflammation and oxidative stress associated with obesity, and may help to explain why obese men may have altered semen parameters, potentially leading to altered fertility.”

“While some of the problems created by paternal obesity may be overcome by assisted reproduction techniques, the swath of implications following fertilization remains to be rigorously investigated,” they note.

The authors conclude the study by writing that efforts should be directed toward the implementation of treatments to correct or limit the observed changes “when weight loss prior to conception is neither practical nor realistic.”

Read more: https://link.springer.com/article/10.1007/s10815-020-01707-8

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