Effect on Sperm DNA Quality Following Sperm Selection for ART: New Insights

Risk of embryo aneuploidy is affected by the increase in sperm DNA damage in recurrent implantation failure patients under ICSI-CGH array cycles

This study investigates the relationship between sperm DNA damage in recurrent implantation failure (RIF) patients treated with comparative genomic hybridisation array-intracytoplasmic sperm injection (CGH array-ICSI) cycles and embryo aneuploidy screening. Forty-two RIF couples were selected. Sperm DFI was measured using TUNEL by flow cytometry. Two groups were defined as follows: (i) sperm with high DFI (> 20%); and (ii) low DFI (< 20%). Semen parameters, total antioxidant capacity (TAC), and malondialdehyde formation (MDA) were also measured in both groups. Following oocyte retrieval and ICSI procedure, blastomere biopsy was performed at the 4th day of development and evaluated with CGH-array. The high DFI group had a significant (p = 0.04) increase in the number of aneuploid embryos compared to the low one. According to Poisson regression results, the risk of aneuploidy embryos in the high DFI group was 55% higher than the low DFI group (RR = 1.55; 95% CI = 1.358-1.772). Moreover, chromosomal analysis showed an elevation of aneuploidy in chromosomes number 16 and 20 in the high DFI group compared to the low DFI group (p < 0.05). The high DFI in RIF patients may significantly affect the risk of aneuploidy embryos. Therefore, embryo selection by CGH-array should be considered for couples with high levels of sperm DNA fragmentation.

Selection of healthy sperm based on positive rheotaxis using a microfluidic device

For conception, sperm cells travel towards the oocyte. This journey is accomplished by only a few sperm cells, following various guidance mechanisms. Of these mechanisms, rheotaxis plays a significant role in guiding the sperm over a long distance. By taking advantage of this natural rheotaxis behavior of sperm, we have developed a microfluidic chip that isolates healthy sperm cells. The developed chip consists of different chambers separated by microchannels that facilitate separation of motile sperm cells from unprocessed semen samples with the help of fluid flow. The sperm cells are subjected to different velocities in different parts of the chip that direct functional sperm towards the collection chamber utilizing positive rheotaxis. The results from the developed microfluidic chip (with 0.5 μL min^-1 flow rate) have shown almost 100% motility, a significantly higher percentage of morphologically normal sperm cells with lesser sperm DNA fragmentation than the control (no-flow) and raw semen sample. This chip satisfies the need of a clinical setting as it is low-cost, easy to operate and uses a small semen volume for sperm sorting.

Beyond conventional sperm parameters: the role of sperm DNA fragmentation in male infertility

Infertility is a condition that widely affects the couples all over the world. In this regard, sperm DNA fragmentation can lead to harmful reproductive consequences, including male infertility and poor outcomes after assisted reproductive techniques. The investigation of SDF in male infertility diagnostics has constantly increased over time, becoming more common in clinical practice with the recent publication of several guidelines regarding its testing. This narrative review aims to provide a comprehensive overview of the pathogenesis and causes of sperm DNA fragmentation, as well as the assays which are more commonly performed for testing. Moreover, we discussed the most recently published evidence regarding the use of SDF testing in clinical practice, highlighting the implications of high sperm DNA fragmentation rate on human reproduction, and the therapeutic approaches for the clinical management of infertile patients. Our review confirms a significant harmful impact of sperm DNA fragmentation on reproduction, and points out several interventions which can be applied in clinics to reduce sperm DNA fragmentation and improve reproductive outcomes. Sperm DNA fragmentation has been shown to adversely impact male fertility potential. As high sperm DNA fragmentation levels have been associated with poor reproductive outcomes, its testing may significantly help clinicians in defining the best therapeutic strategy for infertile patients.

Cross flow coupled with inertial focusing for separation of human sperm cells from semen and simulated TESE samples

A triplet spiral channel coupled with cross-flow filtration has been designed and fabricated in an effort to separate sperm cells from either semen or simulated testicular sperm extraction (TESE) samples. This device separates a fraction of cells from the sample by taking advantage of inertial focusing combined with hydrodynamic filtration in multiple micro-slits. Compared to the conventional swim-up technique, the proposed microfluidic device is capable of efficiently separating sperm cells without any tedious semen sample processing and centrifugation steps with a lower level of reactive oxygen species and DNA fragmentation. The device processing capability on the simulated TESE samples confirmed its proficiency in retrieving sperm cells from the samples with an approximate yield of 76%. Conclusively, the introduced microfluidic device can pave the path to proficiently separate sperm cells in assisted reproductive treatment cycles.

Effect of epigallocatechin-3-gallate (EGCG) on embryos inseminated with oxidative stress-induced DNA damage sperm

Cryopreservation can induce damage in human spermatozoa through reactive oxygen species (ROS) generation. To reduce the potential risk of oxidative stress-induced sperm DNA damage, addition of different epigallocatechin-3-gallate (EGCG) concentrations were performed to determine the optimum concentration which was beneficial for IVF outcome for both fresh and frozen-thawed sperm. Next, the mouse sperm model exhibiting oxidative stress-induced DNA damage by exogenously treating with H₂O₂ but overcoming the low fertilization rate of frozen-thawed sperm was used to investigate the effect of EGCG on the embryonic development and the potential EGCG-mediated effects on ataxia telangiectasia mutated (ATM) pSer-1981 in zygotes, the latter was known for leading to the activation of major kinases involved in the DNA repair pathway and the cell cycle checkpoint pathway. We found the fertilization and embryonic development of embryos inseminated with frozen-thawed sperm was impaired compared to fresh sperm. EGCG promoted the development of embryos inseminated with both types of sperm at optimum concentration. In embryos inseminated with the H₂O₂ sperm, fertilization, embryonic development, and the time at which the cleavage rate of one-cell embryos reached ≥95% were not affected by EGCG treatment. However, the EGCG-treated group required less time to achieve 50% cleavage rate of one-cell embryos, and the EGCG-treated zygotes showed enhanced expression of ATM (pSer-1981) than the untreated group. EGCG at optimum concentrations may exert beneficial effects by modulating the ATM activation and moving up the time to enter into mitotic (M) phase.

ABBREVIATIONS

ROS: reactive oxygen species; EGCG: epigallocatechin-3-gallate; ATM: ataxia telangiectasia mutated; M: mitotic.