Ten-year variation in semen parameters and sperm deoxyribonucleic acid integrity in a healthy fertile man

Bacteriospermia in men among infertile couples in the Nepalese population

Infection of the male urogenital tract or male accessory glands is considered one of the important causes of male infertility, and results in the presence of bacteria in semen affecting the fertility potential of men. This study aims to understand the rate of seminal infection in infertile men, and its association with semen parameters related to fertility potential. The study was carried out from June 2021 to July 2022, in which 217 semen samples were collected from male partners of couples consulting for fertility complaints in a fertility center in Nepal. Analysis of semen parameters was done following the WHO guidelines for human semen analysis, 2021. Microbiological assessment of semen by culture-based approach showed bacteriospermia among 25.3% of samples. Staphylococcus aureus was the predominant isolate in semen. The volume of semen was reduced (p = 0.001 at 95% confidence interval) with bacteriospermia. The concentration, total motility, morphology, and vitality of spermatozoa in the samples tended to be negatively impacted due to bacteriospermia, however, the associations were insignificant at 95% CI. Our study indicates impairment of semen parameters is partially associated with bacterial infection, and hence bacteriospermia may be an important cause of male infertility. Our data represent a baseline for future in-depth studies on bacterial infection in the semen of infertile men in Nepal.

High sperm DNA fragmentation delays human embryo kinetics when oocytes from young and healthy donors are microinjected

BACKGROUND

Time-lapse monitoring (TLM) technology has been implemented in the clinical setting for the culture and selection of human embryos. Many studies have assessed the association between sperm DNA fragmentation (sDNAf) and clinical outcomes after ART, but little is known about the influence of sDNA on embryo morphokinetics.

OBJECTIVES

The objective of this retrospective study, which includes 971 embryos from 135 consecutive ICSI cycles (56 cases with own oocytes, 79 with oocytes from young and healthy donors), was to assess if sDNAf has an impact on embryo morphokinetics.

MATERIALS AND METHODS

Samples used to perform ICSI were analyzed by the flow cytometry TUNEL assay, and embryo development was assessed through an EmbyoScope^® system. The association between sDNAf and the timings of cell cleavage was analyzed by categorizing the first variable into quartiles: ≤6.50%; 6.51-10.70%; 10.71-20.15%; >20.15%.

RESULTS

In cases where sDNAf was above 20.15% (the upper quartile), embryos derived from donated oocytes (n = 644) showed significantly slower divisions. Such association was not observed in embryos obtained from the patients' own oocytes (n = 327). The embryo cleavage pattern (either normal, direct from 1 to 3 blastomeres, direct from 1 to 4 blastomeres, incomplete, reversed or asynchronous) was independent of the sDNAf level. Blastocyst arrival rate was 63.0% and the rate of good quality embryos (transferred and frozen embryos divided by the number of zygotes) was 45.49%. Neither parameter was related to the levels of sDNAf.

DISCUSSION

According to our results, the association between high sDNAf and donated oocytes led to delayed cell division. To our knowledge, this is the first study suggesting that sDNAf can delay human embryo cleavage timings when oocytes from donors are inseminated.

CONCLUSIONS

This finding may indicate that, in the presence of increased DNA damage, time is needed before the first embryonic cell division for the activation of the optimal DNA repairing machinery in higher quality oocytes.

Sperm DNA fragmentation after radioiodine treatment for differentiated thyroid cancer

Background

Treatment of differentiated thyroid cancer usually consists of a total thyroidectomy followed by one or several courses of radioiodine (¹³¹I). ¹³¹I is known to have deleterious effects on radiation sensitive tissues and irradiation to the testes has been shown after its administration. We investigated effects of such treatment on sperm DNA in a patient with differentiated thyroid carcinoma.

Methods

The patient, a 32-year-old male with differentiated thyroid carcinoma treated by total thyroidectomy and radioiodine therapy, performed 6 semen samples in total, 3 for sperm banking and 3 for semen exploration, that were analysed for classic semen parameters. DNA integrity was analysed by flow cytometry: sperm DNA fragmentation index (DFI) and high DNA stainability (HDS) were analyzed by sperm chromatin structure assay, DNA fragmentation was analyzed by terminal deoxynucleotidyl transferase dUTP nick end labeling assay.

Results

Moderate oligozoospermia was observed as early as 3 months after a first dose of ¹³¹I and became severe at 5 months. Total sperm count was reduced up to 12 months after the second dose of ¹³¹I. Sperm DFI was increased 3.25 months after the first dose of ¹³¹I. All parameters returned to normal values 28 months after the second ¹³¹I dose.

Conclusions

Treatment with ¹³¹I induces alterations in sperm chromatin as well as in sperm parameters a short time (3 months) after a first dose of ¹³¹I with persistence of sperm alterations until 12 months after a second dose. Sperm banking should be recommended before treatment.

Effect of sperm DNA fragmentation on pregnancy outcome depends on oocyte quality

OBJECTIVE

To quantify the effect of sperm DNA fragmentation (SDF) on reproductive outcome by evaluating the most statistically significant bias factors using logistic regression.

DESIGN

Prospective blind observational cohort study.

SETTING

University affiliated private IVF unit.

PATIENT(S)

Two hundred ten male partners of couples undergoing in vitro fertilization (IVF) or first intracytoplasmic sperm injection (ICSI) cycles with fresh or thawed sperm with the women's own or donated oocytes.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

SDF determined before and after swim-up (n=420), odds ratio calculated of the effect of an increase of one unit of SDF on pregnancy, and stratified regression analysis performed to evaluate the confusion effect of oocyte quality, sperm origin, and the fertilization procedure.

RESULT(S)

The effect of SDF on pregnancy was not affected by sperm origin (fresh or thawed) or fertilization procedure when measured both before and after swim-up. When oocytes from infertile patients were employed, SDF had a statistically significant negative impact on chance of pregnancy. For every 10% increase in SDF, the probability of not achieving pregnancy increased by 1.31. When donated oocytes were employed, SDF did not have a statistically significant effect.

CONCLUSION(S)

The effect of SDF on the probability of pregnancy can be calculated independent of the fertilization procedure or sperm origin. Oocyte quality conditions the extent of the negative impact of SDF on pregnancy; this can be overcome when good quality oocytes are employed.

Comparing flow cytometry and fluorescence microscopy for analyzing human sperm DNA fragmentation by TUNEL labeling

Conflicting results are reported by recent studies comparing flow cytometry (FCM) and fluorescence microscopy (FM) for detecting sperm DNA fragmentation by TUNEL assay. Each of the two technologies has specific peculiarities and limitations, but whereas the limitations of FM observation are well known, the biases due to the inability of FCM to recognize morphologically analyzed cells are less explored. In particular, so far, FCM analysis of sperm DNA fragmentation have included in the analyses M540 bodies, round semen structures exhibiting FSC/SSC properties similar to sperm. Semen M540 bodies, altogether with the occurrence of two sperm populations with different nuclear staining, concur to an underestimation of values of sperm DNA fragmentation by FCM. However, even considering such bias, the observed discrepancies between the performance of FM and FCM are not fully explained. We discuss here the possible variables that may affect the results of each of the two technologies and the necessary efforts to be taken to address this issue.

High risk of temporary alteration of semen parameters after recent acute febrile illness

OBJECTIVE

To report parameters in semen samples and sperm deoxyribonucleic acid integrity in a fertile volunteer presenting a 2-day fever of 39 degrees -40 degrees C.

DESIGN

Case report.

SETTING

University-affiliated teaching hospital.

INTERVENTION(S)

None.

PATIENT(S)

Semen samples from a fertile volunteer of proven fertility were obtained and analyzed before the febrile illness episode and at days 15, 37, 58, 79, and >180 after the fever.

MAIN OUTCOME MEASURE(S)

Semen parameters (total sperm count, motility a+b, and vitality), sperm protamination state, measured by sperm chromatin structure assay (SCSA) and apoptotic activities, measured by terminal uridine nick-end labeling (TUNEL) assay.

RESULTS

Total sperm count significantly decreased at days 15, 37, and 58 after the fever and returned to normal by day 79 after the fever. The percentage of motility significantly decreased at days 15 and 37 after the fever and returned to normal by day 58. Vitality score also showed a slight, although not statistically significant, decrease after the fever. The DNA fragmentation index (DFI, a SCSA parameter), which defines abnormal chromatin structure, significantly increased by 24% and 36% at days 15 and 37 after the fever, respectively, and decreased to 15% and 8% when reaching days 58 and 79 after the fever. High DNA stainability (HDS, a SCSA parameter) also significantly increased at day 37 after the fever. On the other hand, sperm DNA fragmentation, as measured by TUNEL assay, increased up to 23% by day 15 after the fever but this was not statistically significant.

CONCLUSION(S)

This report demonstrates that a febrile episode can have marked effects on semen parameters and sperm DNA integrity. These results are particularly important for the counseling of infertile couples and in relation to assisted reproductive techniques (ART).